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Compilation Systems Volume 1 (Tools)

1. 0 0 eee ee ee 24 20 Mod le Entries 2 22 22 ernennen 24 22 Subroutine and Entry Point Entries 0 00 0 0000 24 23 General Subroutine and Entry Point Information 24 23 Subroutine and Entry Point Return Types esee 24 23 Subroutine and Entry Point Locations 0000000085 24 24 xviii Contents Declarations Owned by Subroutines and Entry Points 24 24 Low Level Information seseeeeeeeee ene ee 24 24 Types Thrown by Exceptions 0 0 00 cece eee eee ee 24 25 Function Template Instantiations 00 0 0 eee eee 24 26 Inline Subroutines eee Ry m 24 26 Abstract Instances see Ru eee ee Pe cea 24 27 Concrete Inlined Instances llle 24 27 Out of Line Instances of Inline Subroutines 24 28 Lexical Block Entries 0 ers ee Kine 24 29 Eabel Entries 2s a e ete etude ae ee 24 29 With Statement Entries lesse 24 30 Try and Catch Block Entries 2 222202 eneneeeeneereren eee 24 30 Data Object and Object List Entries 0 0 0 eee ee eee 24 31 Data Object Entries cui ad 24 31 Common Block Entries ooo cooococoooocoococ ees 24 33 Imported Declaration Entries 0 0 eee 24 33 Namelist Entries eot ERE e RR eed 24 33 Type Entries es tete eee ee e d de RA e CARA dad 24 34 Base Type Entries ec 00 er ea es DR RURSUS pn 24 34 Type Modifier Entries riea E E ERU E ERE
2. 0 00 0 eee eee eee ee 4 24 Mapfile Structure and Syntax 0 eee eee 4 24 Segment Declarations 0 0 00 0c eee eee 4 25 Mapping Directives 0 eect e 4 27 Extended Mapping Directives 0 00 0 000 2 e eee 4 28 Size Symbol Declarations 0 0 0 0c eee eee ee 4 28 Mapping Example 0 0 eee eee 4 29 Mapfile Option Defaults 0 0 ee eee 4 30 Internal Map Structure 2 2 ees 4 31 Error Messa pes cimil ple dee ee et nenn 4 34 Quick Reference Guide 0 00 cc eet nes 4 35 Compilation Systems Volume 1 Tools Introduction Link Editor and Linking 4 Link Editor and Linking Linking is the process of combining object files to produce an executable or another object file Linking may be done statically or dynamically The 1d command is the static linker often referred to as the link editor The inputs to 1d are relocatable object files produced by a compiler by the assembler or by a previous invocation of the link editor The link editor combines these object files to form either a relocatable or an absolute in other words executable object file There is no system command which performs dynamic linking Dynamic linking is performed by user code during the execution of a program The link editor supports a command language that allows you to control the 1d process with great flexibility and precision Most users however do not re
3. The next step is to add the define for the new symbol MAXSIZE Because the header file in which the define is to appear is not among the files whose lines are displayed you must escape to the shell by typing The shell prompt will appear at the bottom of the screen Then enter the editor and add the define Text string 100 File Line err c 19 p total 100 0 get percentage Hind tel aka CIAO OA AE d ehar SOON ene A tio a a tale lt lt ROON EFE tead ci Ta te o ss 000 Find this C symbol Find this global definition Find functions called by this function Find functions calling this function Find this text string Change this text string Find this egrep pattern Find this file Find files including this file vi defs h Screen 9 14 Escaping from cscope to the Shell To resume the cscope session quit the editor and press Ctrl d to exit the shell Adding an Argument to a Function Adding an argument to a function involves two steps editing the function itself and adding the new argument to every place in the code where the function is called cscope makes that easy First edit the function by using the second menu item Find this global definition Next find out where the function is called Use the fourth menu item Find functions calling this function to get a list of all the functions that call it With this list you can either invoke the editor for each line found by entering the
4. 0 reenen p enoet etae e eh 2 5 Comments e ecd We a ect en t bnt 2 5 Identifiers eed cree E DRESD RERO ns Da sehe 2 5 Predefined Symbols ua 25084358 meni De etr een 2 6 User Defined SymbolS o oooocccocococooo es 2 8 Constant aii eee hee pe RR eie ciel ne 2 8 Integer Const nts ss seses iler l e nee RR 2 8 Floating Point Constants o ooooocococoro eh 2 8 Character Constants sores e HR YE RE e 2 9 ERPFESSIONS ln gts EE Le e eee eec ee ede 2 9 Expression Operators ooooocoocooooo onen enen nenn 2 10 Operator Precedence ette et meet De eet seed 2 10 Expression TY P68 ru RARE RES UNDE ERES se OSEE es 2 11 Expression Values ie e nem o ph Rcgc e SCR gne 2 11 Assembler Directives resser e ee e AE mee 2 12 Location Counter Control 2 0 00 0 eee eee eee 2 12 Section Switching eR E ee oes ee eR 2 13 Data Initialization oa a beaches eate 2 14 Symbol Definitions llle e 2 16 ELE Symbol Attributes ieee kee LLL adea Sealy sets In 2 17 Miscellaneous Operations 0 0 0 0 eee eee ete ee 2 18 Summary of Directives Mnemonics 00 0000 c eee eee 2 19 Example ii cee tah ng DE Der RET Ae i ee 2 20 Position Independent Code o ooooooocoococr eee 2 21 Assembly Syntax wc eec RR e IU E EY RR RE 2 21 Example 15 e ese e teer e as fe nactus 2 22 Compilation Systems Volume 1 Tools 2 Assembler and Assembly Language Introduction Concurrent Computer Corporation s as
5. 10 4 warning logical expression always true op 6 warning logical expression always true op 7 warning logical expression always true op 10 26 Analyzing Your Code with lint malformed format string Format Compound En in the list of directives in Usage on A fs printf or fs scanf control string was formed incorrectly See also PRINTFLIKEn and SCANFLIK page 10 6 include stdio h main malformed format string printf test c 4 may be indistinguishable due to truncation or case Format Compound External names in a program may be indistinguishable when it is ported to another machine due to implementation defined restrictions as to length or case The message is issued only when lint is invoked with Xc or p Under Xc external names are truncated to the first 6 characters with one case in accordance with the ANSI C lower bound under p to the first 8 characters with one case file 1 c 1 int foobarl 2 int FooBarl2 file 2 c 1 int foobar2 2 int FOOBAR12 under p may be indistinguishable due to truncation or Case FooBarl2 El eZ FOOBAR12 2 c 2 under Xc may be indistinguishable due to truncation or case foobarl fe 1 FooBarl2 fl c 2 foobarl fl c 1 foobar2 E201 foobarl fl c l FOOBAR12 EZ 202 name declared but never used or defined Format Compound A non static external variable or function was declare
6. The user list to determine if the login name or group ID of the person executing get is present The login name or group ID must be present for the user to be allowed to make deltas See The admin Command on page 14 19 for a discussion of making user lists The release number R of the version being retrieved to determine if the release being accessed is a protected release That is the release number must satisfy the relation floor is less than or equal to R which is less than or equal to ceiling floor and ceiling are flags in the SCCS file representing start and end of the range of valid releases Ris not locked against editing The lock is a flag in the SCCS file e Whether multiple concurrent edits are allowed for the SCCS file by the j flag in the SCCS file A failure of any of the first three conditions causes the processing of the corresponding SCCS file to terminate If the above checks succeed get e causes the creation of a g file in the current directory with mode 644 readable by everyone writable only by the owner that is owned by the real user If a writable g file already exists get terminates with an error Any ID keywords appearing in the g file are not replaced by get e because the generated g file is subsequently used to create another delta In addition get e causes the creation or updating of the p file that is used to pass information to the de1ta command The following get e s
7. 4 11 Specifying Directories to Be Searched by the Link Editor 4 13 Specifying Directories to Be Searched by the Dynamic Linker 4 15 Checking for Run Time Compatibility ooooooocoocoococcococo oo 4 16 Dynamic Linking Programming Interface 0 0 0 eee ee eee eee 4 17 Implementation A as 4 17 Guidelines for Building Shared Objects 000 00 e eee ee 4 18 Multiply Defined Symbols 0 0 0 4 22 Mapfiles nasse Bae IS S ioe ee PES 4 23 Using the Mapfile Option 00 0 eee 4 24 Mapfile Structure and Syntax 0 eee eee 4 24 Segment Declarations irose aner uE E eee 4 25 Mapping Directives 20 0 eee cette eens 4 27 Extended Mapping Directives 000 002 eese 4 28 Size Symbol Declarations 0 00 0 e cece eee 4 28 Mapping Example 2 ta u E T eee 4 29 Mapfile Option Defaults 00 0 4 30 Internal Map Structure 4 31 Error MesSagES eiii ct m is tete iate art an 4 34 Quick Reference Guide 0 0 ccc cette nenn 4 35 Chapter 5 m4 Macro Processor viii Introduction A NCBI Remb e ee M a RAS 5 1 TIN M CEOS eee ee E B oa ds 5 2 Defining Macros 2 dee oe ee a 5 2 Quoting i does reside eto ttes des ae cte ee dette Ros 5 3 ATSUMENIS e xe ie Sc ee DURO EE US as Ne EHE Re MERE 5 5 Arithmetic Built Ins 2 0 00 er ha 5 7 File melusion us a wr 5 7 DIVeESIODS s 4 cee ses e et d oet
8. 6 Lexical Analysis with lex Introduction 35 5 o es eG gn ds Generating a Lexical Analyzer Program 0 2 0 0 ec ee eee ee Writing lex So rce ce an are DERE Ee aad tote ae tes EA re The Fundamentals of lex Rules 00 cece cece ee ee Regular Expressions 2 2 2222 0 cece cee eee eee nee eens Operators idee pola dit ee ACUONS e RR CAU EN ROUES MA RO Eee Advanced lex Usage iii er eer Le ER Cte a Some Special Features 0 0 cee ee res lex ROUTINES s a ete t vc CRUS cra Definition 3 nee A UR b FRATRE NA ene Start Conditions coa CELL V Up De eene eeu ser ROUtINES 5400 0 rnm 502 a NOE Using lex with yace acia ee en ea ie de Gl athens Miscellaneous annant eti RERUMS EN EIER EAT YER ACER Summary of Source Format e sooo esee ee sura ea a e e eee eee Compilation Systems Volume 1 Tools Introduction 6 Lexical Analysis with lex lex is a software tool that lets you solve a wide class of problems drawn from text processing code enciphering compiler writing and other areas In text processing you might check the spelling of words for errors in code enciphering you might translate certain patterns of characters into others and in compiler writing you might determine what the tokens are in the program to be compiled The task common to all these problems is lexical analysis recognizing different strings of characters that satisfy certain characteristics Hence the name lex You don t
9. Diverted text is normally output at the end of processing in numerical order Diversions can be brought back at any time by appending the new diversion to the current diversion Output diverted to a stream other than 0 through 9 is discarded The built in undivert brings back all diversions in numerical order undivert with arguments brings back the selected diversions in the order given Undiverting discards the diverted text as does diverting into a diversion whose number is not between 0 and 9 inclusive The value of undivert is not the diverted text Furthermore the diverted material is not rescanned for macros The built in divnum returns the number of the currently active diversion The current output stream is 0 during normal processing System Command Conditionals 5 8 Any program can be run by using the syscmd built in syscmd date invokes the UNIX operating system date command Normally syscmd would be used to create a file for a subsequent include To make it easy to name files uniquely the built in maketemp replaces a string of XXXXX in the argument with the process ID of the current process Arbitrary conditional testing is performed with the built in ifelse In its simplest form ifelse a b c d m4 Macro Processor compares the two strings a and b If a and b are identical ifelse returns the string c Otherwise string d is returned Thus a macro called compare can b
10. 1 void fun 2 3 TNE ap Dr Gp 23 4 a 5 a 5 6 r 7 while x 10 8 a b amp amp c a 9 a b amp amp c a 10 a b 11 statement has null effect 4 5 9 statement not reached Format Compound A function contained a statement that cannot be reached Preceding an unreached state ment with NOTREACHED suppresses the message for that statement invoking lint with b suppresses it for every unreached break and empty statement Note that this message is also issued by the compiler but cannot be suppressed 10 33 Compilation Systems Volume 1 Tools static unused 1 void fun a 2 3 switch a 4 case 1 5 return 6 break 7 case 2 8 return 9 NOTREACHED 10 break 11 12 statement not reached 6 Format Compound A variable or function was defined or declared static in a file but not used in that file Doing so is probably a programming error because the object cannot be used outside the file 1 static 2 static 3 static 4 static int x int main static unused 4 y 3 foo 2 main 1 x suspicious comparison of char with value op 0p 10 34 Format Simple A comparison was performed on a variable of type plain char that implied it may have a negative value lt 0 lt 0 gt 0 gt 0 Whether a plain char is treated as signed or non negative is implementatio
11. 3 VREG vexp vreg 1 3 GIOI yyerrok Parsing with yacc 7 35 Compilation Systems Volume I Tools 1o Sosa 4 ae dere oa void YYERROR vexp dexp vexp dexp vexp dexp vexp aise dexp alse 7 36 Roch E AR le hi mes loue hi lo hi Rae Lou UE OE VELS EG Vx vmul 1 ufr dcheck 3 va o elo yu dcheck 3 vdiv 1 vexp printf interval out of order n Slane puke vexp S s SO vexp SIENI 93 7 vexp 1 3 vexp YYERROR l hi 3 vexp YYERROR 1 3 Parsing with yacc Soh S210 SS LOS Zi his o vexp S beginning of subroutines section define BSZ 50 buffer size for floating point number lexical analysis int yylex register int c skip over blanks while c getchar 2 F if isupper c yylval ival return VREG islower c yylval ival return DREG gobble up digits points exponents ES mg A E chorsbULLBSZE AA E COSI Ute int dot 0 exp 0 LOLAS BS ZA CAOS CASI e ODIO ME Caso Bre abe o0 continue Stine ence berg rf dot exp Te Ud peau will cause syntax error continue 7 37 Compilation Systems Volume I Tools exp return e will cause syntax error continue end of n
12. Delta Numbering 2 peck ns ee ee tbh ee tee bees 14 5 SCCS Command Conventions 0 0 000 een 14 7 AE ad ZE Rr me 14 8 Error Messages asiaa ree atit A red a atus MUR 14 8 SCGS Commands eor UE ACER ace dye URB E SER dg 14 8 The get Command ee ee ege a ee eere eee 14 9 ID Keywords eene eR eich Da SS rn CER 14 10 Retrieval of Different Versions nnan 0 0 ees 14 10 To Update Source cte REIR EE DR en en 14 12 Undoing d get e isk eo Le ee ent E Eg 14 13 Additional get Options 0 0 eee ee e 14 13 Concurrent Edits of Different SID o o ooooooooooooooo ooo 14 13 Concurrent Edits of Same SID 0 ene 14 15 Key letters that Affect Output llle 14 16 The delta Commands eoe REM E ea er Rs 14 17 The admin Command 0 0 0 cee een 14 19 Creation of SCES FIES t 14 19 Inserting Commentary for the Initial Delta o o o ooooo 14 20 Initialization and Modification of SCCS File Parameters 14 20 The prs Command run seen ERR E RUE 14 21 Th sact Command 2 o2 a SEED ARP ne Pw ad Dea 14 23 The help Command sipe ni ipon etiani ee en athe 14 23 Thie rmdel Command ui it ERE ARR ne RN 14 23 The cdc Command 6 cence nee enes 14 24 The what Command 2 2 2 as 14 24 The sccsdiff Command 0 0 0 0 00 cee nets 14 25 The comb Command 0 0 ccc eee 14 25 The val Command LL fe rere Re Uem 14 26 SCGS BIleSsa a Nee eren ESAE nn EEE ive de ebb
13. Examples TOKEN LEFT RIGHT NONASSOC TIRE empty union tag is optional Vo ED E Nae Reels nmno nlist nmno se oo IDENTIFIER Note literal invalid with type IDENTIFIER NUMBER Note invalid with type 7 PATAS section 7 rules C_IDENTIFIER rbody prec rules rule C_IDENTIFIER rbody prec rbody prec empty rbody IDENTIFIER rbody act C Copy action translate etc nye empty PREC IDENTIFIER PREC IDENTIFIER act rece 1 A Simple Example 7 30 This example gives the complete yacc applications for a small desk calculator the calculator has 26 registers labeled a through z and accepts arithmetic expressions made up of the operators and the assignment operators If an expression at the top level is an assignment only the assignment is done otherwise the expression is printed As in the C language an integer that begins with 0 is assumed to be octal otherwise it is assumed to be decimal Parsing with yacc As an example of a yace specification the desk calculator does a reasonable job of showing how precedence and ambiguities are used and demonstrates simple recovery The major oversimplifications are that the lexical analyzer is much simpler than for most appli cations and the output is produced immediately line by line Note the way that decimal and octal integers are read in by grammar rules This job is probably better done by
14. Move From Thermal 1 750 only Supervisor Level Same as mfspr rT 1021 Move From Thermal 1 750 only Supervisor Level Same as mfspr rT 1022 Move From User Mask Register 0 750 only Same as mfspr rT 936 Move From User Mask Register 1 750 only Same as mfspr rT 940 Move From User Performance Monitor Counter 1 750 only Same as mfspr rT 937 Move From User Performance Monitor Counter 2 750 only Same as mfspr rT 938 Move From User Performance Monitor Counter 4 750 only Same as mfspr rT 941 Move From User Performance Monitor Counter 4 750 only Same as mfspr rT 942 Move From User Sampled Instruction Address Register 750 only Same as mfspr rT 939 Move From Fixed Point Exception Register Same as mfspr rT 1 Move Register Same as or rT rA rA Move To Address Space Register Supervisor Level Same as mtspr 280 rS Move To Block Address Translation Lower n 601 only Supervisor Level Same as mtspr 529 2n rS Move To Block Address Translation Upper n 601 only Supervisor Level Same as mtspr 528 2n rS Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC Mnemonic Syntax of Operands RS 6000 Description POWER Mnemonic mtbuscr mtcr mtcrf mtctr mtdabr mtdar mtdbatl mtdbatu mtdec mtdsisr mtear mtesasrr mtfpecr mtfsbO IS IS FXM rS IS IS IS n rS n rS IS IS IS IS
15. O option r file Print summary statistics for each routine to file s routine Subtract a routine from the list to be analyzed It pairs with the A option much like N and a team up only inverted v Annotate the disassembly listing with the details about which instructions are using which machine resources at each cycle w Suppress the output of warning messages Z keyword Pass a keyword option to analyze The keywords recognized on the Z option are PPC604 Disassemble instructions as they would be interpreted on a Pow erPC 604 system By default instructions are disassembled as they would be interpreted relative to a PowerPC 604 system It also causes C to emulate the cache behavior of the PowerPC 604 system PPC601 Disassemble instructions as they would be interpreted on a Pow erPC 601 system By default instructions are disassembled as they would be interpreted relative to a PowerPC 601 system It also causes C to emulate the cache behavior of the PowerPC 601 system break name Tell analyze the name of the global variable used to contain the break address This variable is used by the brk and sbrk routines to track the next available heap address When using the P option the initial value of this variable must be patched The default name is curbrk exclude register Exclude the named register from the list of registers used to optimize out lis instruction It may be used multiple times
16. fT fB Floating Convert to Integer Word fctiwz fT fB Floating Convert to Integer Word with round toward Zero fdiv s fT fA fB Floating Divide double precision not on 602 fd fmadd s fT fA fB fC Floating Multiply Add double precision not on 602 fma fmr fT fB Floating Move Register y 3 7 Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC RS 6000 Syntax of Operands Description POWER Mnemonic Mnemonic fmsub s fT fA fB fC Floating Multiply Subtract double precision not on fms 602 fmul s fT fA fC Floating Multiply double precision not on 602 fm fnabs fT fB Floating Negate Absolute Value A fneg fT fB Floating Negate E fnmadd s fT fA fB fC Floating Negate Multiply Add double precision not on fnma 602 fnmsub s fT fA fB fC Floating Negate Multiply Subtract double precision fnms not on 602 fres fT fB Floating Reciprocal Estimate Single optional not on 601 frspl fT fB Floating Round to Single Precision double precision not on 602 frsqrte fT fB Floating Reciprocal Square Root Estimate optional not on 601 fsel fT fA fC fB Floating Select optional not on 601 fsqrt s fT fB Floating Square Root optional Not on 601 602 fsqrt 603 e 604 e RS 6000 POWER2 only fsub s I fT fA fB Floating Subtract double precision not on 602 fs icbi rA rB Instruction Cache Block Invalidate inslwi rA r
17. hand specify all SCCS files admin h s filel s file2 or admin h directory directory2 If the new checksum of any file is not equal to the checksum in the first line of that file the message corrupted file co6 is produced for that file The process continues until all specified files have been examined When examining directories as in the second example above the checksum process will not detect missing files A simple way to learn whether files are missing from a directory is to execute the 1s command periodically and compare the outputs Any file whose name appeared in a previous output but not in the current one no longer exists When a file has been corrupted the way to restore it depends on the extent of the corruption If damage is extensive the best solution is to contact the local UNIX system operations group and request that the file be restored from a backup copy If the damage is minor repair through editing may be possible After such a repair the admin command must be executed Tracking Versions with SCCS admin z s file The purpose of this is to recompute the checksum and bring it into agreement with the contents of the file After this command is executed any corruption that existed in the file will no longer be detectable 14 29 Compilation Systems Volume 1 Tools 14 30 Symbols pragma 4 23 align directive 2 12 ascil directive 2 16 asciiz directive 2 16 bss directive 2 17
18. 1 struct u 2 unsigned v 1 3 int webs 4 char x 9 5 long y 8 6 short z 8 7 3 warning nonportable bit field type 4 warning nonportable bit field type 5 warning nonportable bit field type 6 warning nonportable bit field type nonportable character constant Format Simple A multi character character constant in the program may not be portable The message is issued only when lint is invoked with Xc 1 warning nonportable character constant only 0 or 2 parameters allowed main Format Simple 10 29 Compilation Systems Volume 1 Tools The function main in your program was defined with only one parameter or more than two parameters in violation of the ANSI C requirement The message is issued only when lint is invoked with Xc 1 main int argc char argv char envp 2 0 2 warning only 0 or 2 parameters allowed main pointer cast may result in improper alignment Format Compound A pointer to one object type was cast to a pointer to an object type with stricter alignment requirements Doing so may result in a value that is invalid for the second pointer type The warning is suppressed when lint is invoked with h 1 void fun 2 3 short s 4 int 1 5 i int s 6 pointer cast may result in improper alignment 5 pointer casts may be troublesome 10 30 Format Compound A pointer to one object type was cast to a pointer to a different object type The me
19. 6 i i amp 055 7 Jue yr 1530225 8 9 warning bitwise operation on signed value nonportable 6 7 10 15 Compilation Systems Volume 1 Tools constant in conditional context Format Simple The controlling expression of an if while or for statement was a constant Preceding the statement with CONSTCOND suppresses the message void fun if 1 return while 1 foo for 1 for CONSTCOND while 1 O00 1o001 00 PK FE 3 warning constant in conditional context 4 warning constant in conditional context 5 warning constant in conditional context constant operand to op Format Simple The operand of the NOT operator was a constant Preceding the statement with CONSTCOND suppresses the message for that statement invoking lint with h suppresses it for every statement 1 void fun 2 3 if 0 return 4 CONSTCOND 5 if 0 return 6 3 warning constant operand to op constant truncated by assignment Format Simple An integral constant expression was assigned or returned to an object of an integral type that cannot hold the value without truncation 10 16 Analyzing Your Code with lint 1 unsigned char f 2 3 unsigned char i 4 i 255 5 i 256 6 return 256 7 5 warning constant truncated by assignment 6 warning constant truncated by assignment conversion of pointer loses bits Format
20. BT FLM fB BFT U IS IS IS n rS n rS IS IS IS IS IS IS Move To FPSRC Bita 1 e Move To FPSCR Fields Move To FPSCR Field Immediate Move To Hardware Implementation Dependent 0 601 602 603 e 604 e 620 only Supervisor Level Same as mtspr 1008 rS Move to Hardware Implementation Dependent 1 601 602 603e 604e only Supervisor Level Same as mtspr 1009 rS Move To Instruction Address Breakpoint Register 601 602 603 e 604 e 620 only Supervisor Level Same as mtspr 1010 rS Move To Instruction Block Address Translation Lower n not on 601 Supervisor Level Same as mtspr 529 2n rS Move to Instruction Block Address Translation Upper n not on 601 Supervisor Level Same as mtspr 52842n rS Move To Interrupt Base Register 602 only Supervisor Level Same as mtspr 986 rS Move To Instruction Cache Throttling Control Register 750 only Move To L2 Status Register 620 only Supervisor Level Same as mtspr 1018 rS Move To Link Register Same as mtspr 8 rS Move To Integer Tag Register 602 only Supervisor Level Same as mfspr 1022 1S Move To Mask Register 0 604 e 620 only Supervisor Level Same as mtspr 952 rS Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont RS 6000 Syntax of Operands Description POWER Mnemonic PowerPC Mnemonic mimmcrl IS Move To Mask Register 1 604e only Supervisor Level Same as
21. IS BT Move To Bus Control amp Status Register 620 only Supervisor Level Same as mtspr 1016 18 Move To Condition Register Same as mtcrf Oxff rS Move To Condition Register Fields Move To Count Register Same as mtspr 9 rS Move To Data Address Breakpoint Register 601 604 e 620 only Supervisor Level Same as mtspr 1013 rS Move To Data Address Register Supervisor Level Same as mtspr 19 rS Move To Data Block Address Translation Lower n not on 601 Supervisor Level Same as mtspr 53742n rS Move To Data Block Address Translation Upper n not on 601 Supervisor Level Same as mtspr 536 2n rS Move To Decrementer Supervisor Level Same as mtspr 22 rS Move To Data Storage Interrupt Status Register Supervisor Level Same as mtspr 18 rS Move To External Access Register optional Supervisor Level Same as mtspr 282 18 Move To Enable Supervisor Access Save and Restore Register 602 only Supervisor Level Same as mtspr 987 rS Move To Floating Point Exception Cause Register optional not on 601 602 603 e 604 e Supervisor Level Same as mtspr 1022 18 Move To FPSRC Bita 0 3 16 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC Mnemonic Syntax of Operands RS 6000 Description POWER Mnemonic mtfsb1 mtfsf mtfsfi mthidO mthidl mtiabr mtibatl mtibatu mtibr mtictc mtl2sr mtlr mtlt mtmmcrO
22. Move From FPSCR i Move From Primary Hash Address 602 603 e only Supervisor Level Same as mfspr rT 978 Move From Secondary Hash Address 602 603 e only Supervisor Level Same as mfspr rT 979 Move From Hardware Implementation Dependent 0 601 602 603 e 604 e 620 only Supervisor Level Same as mfspr rT 1008 Move From Hardware Implementation Dependent 1 601 602 603e 604e only Supervisor Level Same as mfspr rT 1009 Move From Instruction Address Breakpoint Register 601 602 603 e 604 e 620 only Supervisor Level Same as mfspr rT 1010 Move From Instruction Block Address Translation Lower n not on 601 Supervisor Level Same as mfspr rT 52942n Move From Instruction Block Address Translation Upper n not on 601 Supervisor Level Same as mfspr rT 52842n Move From Interrupt Base Register 602 only Supervisor Level Same as mfspr rT 986 Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC Mnemonic Syntax of Operands RS 6000 Description POWER Mnemonic mficmp mfictc mfimiss mfl2cr mfl2sr mflr mflt mfmmcrO mfmmcrOrd mfmmerl mfmq mfmsr mfpir IT IT IT IT IT IT IT IT IT rT 1T IT IT Move From Instruction TLB Compare 602 603 e only Supervisor Level Same as mfspr rT 981 Move From Instruction Cache Throttling Control Regis ter 750 only Supervisor Le
23. Small mnemonics Signify instructions defined for 64 bit implementations only Signify extended mnemonics added by Concurrent Com puter Corporation that are not present in IBM or Motorola documentation Signify IBM RS 6000 POWER instructions that are provided on the PowerPC 601 systems for compatibility purposes In all columns except the Syntax of Operands column the following codes that represent variations of the instructions appear o 1 a s u Cause the SO and OV bits to be set in the fixed point exception register For integer instructions cause crf0 to be set as though the result were compared to zero for floating point instructions cause crfl to be set with the high order four bits of the floating point status and control register Cause link register to be set to the return address Cause the displacement to be taken as an absolute address Cause the floating point result to be rounded to single precision Cause rA to be updated with the effective address of the load or store In the Syntax of Operands column operand Signify an operand the assembler allows you to omit This feature is not documented in the IBM documentation but is a carry over from the Rios assembly language 3 1 Compilation Systems Volume 1 Tools In the Description column operand defaults to value optional optional not on xxx xxx only xxx e Signifies the default value for
24. conditional preprocessing 5 8 5 9 m4 1 defining macros 5 2 5 5 m4 1 file manipulation 5 7 5 8 m4 1 quoting 5 3 5 5 m4 1 string handling 5 9 5 10 Machine language 2 1 Macro preprocessor 1 5 make 1 13 1 13 24 make 1 command line 13 16 13 18 make 1 environment variables 13 18 13 19 make 1 how to write source 13 2 13 8 make 1 macros 13 3 13 8 13 10 13 12 make 1 maintaining libraries 13 11 13 12 make 1 makefile convention 13 1 make 1 sample output 13 4 13 5 make 1 source format 13 6 make 1 suffix transformation rules 13 9 13 11 13 19 13 24 make 1 usage example 13 4 13 5 make 1 use with SCCS 13 13 13 14 MAKEFLAGS environment variable 13 18 Manipulator 1 5 mapfiles 4 35 defaults 4 30 error messages 4 34 example 4 29 map structure 4 31 mapping directives 4 27 segment declarations 4 25 size symbol declarations 4 28 structure 4 24 syntax 4 24 usage 4 24 Math library 16 2 math library linking with linking with 4 11 Mathematic and numeric functions 16 36 Mathematic functions 16 38 mcs 1 1 5 Memory Allocation 16 29 16 30 Memory allocation functions 16 29 Memory control functions 16 30 Memory functions 16 28 Memory Manipulation Functions 16 28 Memory manipulation functions 16 28 Message catalog functions 16 36 Message queue functions 16 32 Index 7 Compilation Systems Volume 1 Tools Messages About copy variables 20 15 About forward branch into loop 20 19 About loop exits 20 22 About loop
25. defined as define bump 1 1 1 is equivalent to x x 1 for bump x A macro can have as many arguments as you want but only the first nine are accessible individually 1 through 9 0 refers to the macro name itself Arguments that are not supplied are replaced by null strings so a macro can be defined that simply concatenates its arguments define cat 1 2 3 4 55 6 7 8 9 cat x y Z is equivalent to xyz Arguments 4 through 9 are null because no corresponding arguments were provided Leading unquoted blanks tabs or new lines that occur during argument collection are discarded All other white space is retained so define a b c defines a to be b Es Compilation Systems Volume 1 Tools 5 6 Arguments are separated by commas A comma protected by parentheses does not terminate an argument define a b c has two arguments a and b c You can specify a comma or parenthesis as an argument by quoting it 1s replaced by a list of the arguments given to the macro in a subsequent invocation The listed arguments are separated by commas define a 1 define b 2 define star star a b gives the result 1 2 staran 2b gives the same result because m4 strips the quotes from a and b as it collects the arguments of star then expands a and b when it evaluates star is identical to except that each argument in the subsequent invocation is quoted define a
26. lt gt and amp Labels may be preceded by zero or more blanks They are terminated by a which does not become part of the label name One or more blanks may precede the colon The assembler does not prefix or suffix additional underscores to the label as some compilers do If a version 03 00 ora version 02 00 directive discussed in ELF Symbol Attributes on page 2 17 does not exist in the assembly file the assembler removes a leading underscore if one exists from label names If a version 03 00 ora version 02 00 directive does exist in the assembly file the assembler does not remove a leading underscore from labels Alphanumeric labels have a maximum length of 1 024 characters For example _labell PCB flag Assembler and Assembly Language An alphanumeric label assigns the current value and type of the location counter to the named symbol In the text section the location counter is the program counter in that section In other sections the location counter is the address of the next data byte in that section Numeric Local Labels Comments Identifiers A numeric label consists of a digit 0 9 followed by a colon It defines a temporary symbol of the form nb or nf where n is the digit of the label and b or indicates a back ward or forward reference respectively A numeric label assigns the current value and type of the location counter to the temporary symbol For example the operand 3b refers to th
27. 0 inserted 1 deleted 6 unchanged Deltas can now be created in release 2 deltas 2 2 2 3 etc or another new release can be created in a similar manner A delta can still be made to the old release 1 This will be explained later in the chapter Tracking Versions with SCCS The help Command If the command get lang is now executed the following message will be output ERROR lang not an SCCS file col The code co1 can be used with help to print a fuller explanation of the message help col This gives the following explanation of why get lang produced an error message col not an SCCS file A file that you think is an SCCS file does not begin with the characters s help is useful whenever there is doubt about the meaning of almost any SCCS message Delta Numbering Think of deltas as the nodes of a tree in which the root node is the original version of the file The root node is normally named 1 1 and deltas nodes are named 1 2 1 3 etc The components of these SIDs are called release and level numbers respectively Thus normal naming of new deltas proceeds by incrementing the level number This is done automati cally by SCCS whenever a delta is made Because the user may change the release number to indicate a major change the release number then applies to all new deltas unless specifically changed again Thus the evolution of a particular file could be represented by Figure 14 1
28. 00 10 15 constant in conditional context 0 0 eee eee ee eee 10 16 constant operand to op Ud Loco 10 16 constant truncated by assignment 0 0 esee 10 16 conversion of pointer loses bits lees 10 17 conversion to larger integral type may sign extend incorrectly 10 17 Contents declaration unused in block 2 0 eee eee 10 18 declared global could be static 0 2 ee eee 10 18 equality operator found where was expected 10 18 evaluation order undefined name 0 0 00 10 19 fallthrough on case statement llle eee 10 19 function argument number declared inconsistently 10 20 function argument number used inconsistently llle esee 10 20 function argument type inconsistent with format 00 10 21 function called with variable number of arguments 10 21 function declared with variable number of arguments 10 22 function falls off bottom without returning value 0 0 10 23 function must return int main 1 2 eens 10 23 function returns pointer to automatic parameter 00 0 10 24 function returns value that is always ignored 0 0005 10 24 function returns value that is sometimes ignored 000 10 25 function value is used but none returned 0 0 0 0 0c cece eee 10 25 log
29. 10 17 declaration unused in block 2 eee 10 18 declared global could be static ee eee 10 18 equality operator found where was expected 10 18 evaluation order undefined name 0 0 0 e eee eee eee 10 19 fallthrough on case statement 10 19 function argument number declared inconsistently 10 20 function argument number used inconsistently 0 0 10 20 function argument type inconsistent with format esse 10 21 function called with variable number of arguments 22222000 10 21 function declared with variable number of arguments 10 22 function falls off bottom without returning value 10 23 function must return int MaiINQ 2 6 ce eens 10 23 function returns pointer to automatic parameter 000 10 24 function returns value that is always ignored 0 000 10 24 function returns value that is sometimes ignored 00 10 25 function value is used but none returned 0 0 0 0 cece 10 25 logical expression always false op amp amp 2 0 ee eee 10 26 logical expression always true op 7II 2 ee eee 10 26 malformed format Stings iseia eee eee 10 27 may be indistinguishable due to truncation or case lise ooo 10 27 name declared but never used or defined 0 000000005 10 27 name defined but
30. Declare segments and specify values for segment attributes such as segment type permissions addresses length and alignment Control mapping of input sections to segments by specifying the attribute values necessary in a section to map to a specific segment the attributes are section name section type and permissions and by specifying which object file s the input sections should be taken from if necessary Declare a global absolute symbol that is assigned a value equal to the size of a specified segment by the link editor and that can be referenced from object files 4 23 Compilation Systems Volume 1 Tools NOTE The major purpose of the mapfile option is to allow users of ifiles an option previously available to 1d that used link editor command language directives to convert to mapfiles All other facilities previously available for ifiles other than those mentioned above are not available with the mapfile option When using the mapfile option be aware that you can easily create a out files that do not execute Therefore the use of the mapfile option is strongly discouraged 1d knows how to produce a correct a out without the use of the mapfile option The mapfile option is intended for system programming use not application programming use This subsection describes the structure and syntax of a mapfile and the use of the M option to the 1d command Using the Mapfile Option To use the mapfile option you m
31. Initially the machine is in state 0 the stack contains only state 0 and no lookahead token has been read The machine has only four actions available shift reduce accept and error A step of the parser is done as follows 1 Based on its current state the parser decides if it needs a look ahead token to choose the action to be taken If it needs one and does not have one it calls yylex to obtain the next token 2 Using the current state and the lookahead token if needed the parser decides on its next action and carries it out This may result in states being pushed onto the stack or popped off of the stack and in the lookahead token being processed or left alone The shift action is the most common action the parser takes Whenever a shift action is taken there is always a lookahead token For example in state 56 there may be an action IF shift 34 which says in state 56 if the lookahead token is IF the current state 56 is pushed down on the stack and state 34 becomes the current state on the top of the stack The lookahead token is cleared The reduce action keeps the stack from growing without bounds reduce actions are appropriate when the parser has seen the right hand side of a grammar rule and is prepared to announce that it has seen an instance of the rule replacing the right hand side by the left hand side It may be necessary to consult the lookahead token to decide whether or not to reduce In fact the de
32. Recursive Makefiles 3 4 2220 82 er een een 13 8 Suffixes and Transformation Rules 0 0 00 eee eee 13 9 Implicit Rules 2 0 2 e RR Dee ee eee 13 9 Archive Libraries 2 00 0c ha 13 11 Source Code Control System File Names 0 00 00 00 o 13 13 The NUS Ei A N D AE det eterne a id 13 13 Included Files 2 22 u aa Es Weegee AUR ROS 13 14 SCCSoMakefiless 22 88 2 oa ti aai oat ete ts 13 14 Dynamic Dependency Parameters 0 0 0 cece ee esee 13 14 Vi wpaths VPATH s ee ne ect adds man 13 15 Command Usage eei 2 lel RID e tees 13 16 The make Command 0 0 0 ccc ce eee e 13 16 Environment Variables 0 0 0 000 llle 13 18 Suggestions and Wamings 0 0 cece cece ee 13 19 Internal Rules REDE a IAE E dues e er 13 19 Compilation Systems Volume 1 Tools Introduction 13 Managing File Interactions with make The trend toward increased modularity of programs means that a project may have to cope with a large assortment of individual files There may also be a wide range of generation procedures needed to turn the assortment of individual files into the final executable product make provides a method for maintaining up to date versions of programs that consist of a number of files that may be generated in a variety of ways An individual programmer can easily forget File to file dependencies Files that were modified and the impact that has on other files The ex
33. This is most often used in a pipeline with grep 1 For example to find all lines that match a given pattern in the latest version of each SCCS file in a directory the following may be executed get p n s directory grep pattern If both m and n are specified each line of the g file is preceded by the value of the M ID keyword and a tab this is the effect of n and is followed by the line in the format produced by m Because use of m and or n causes the contents of the g file to be modified such a g file must not be used for creating a delta Therefore neither m nor n may be specified together with get e See the get 1 page The delta Command The delta command is used to incorporate changes made to a g file into the corresponding SCCS file that is to create a delta and therefore a new version of the file The delta command requires the existence of p file created by get e It examines p file to verify the presence of an entry containing the user s login name If none is found an error message results The delta command performs the same permission checks that get e performs If all checks are successful delta determines what has been changed in the g file by comparing it with its own temporary copy of the g file as it was before editing This temporary copy is called d file and is obtained by performing an internal get on the SID specified in the p file entry The required p file e
34. This new representation can be an assembly language representation of the higher level source code making it necessary to run an assembler to produce a machine level representation of the code Sometimes a compiler will translate the high level language directly into the machine level representation A compiler analyzes the source code both syntactically and semantically A good compiler detects as many errors as it can locate enabling the programmer to correct them before they occur during execution of the program A good compiler can also optimize the program Optimization transforms the program allowing it to run faster and more efficiently Some languages are processed by an interpreter Whereas a compiler produces output that must be further processed and then executed an interpreter performs on the fly translation and execution of the program Assembly language is processed by an assembler Assemblers are usually less sophisticated than compilers and interpreters An assembler often does nothing more than convert the specified assembly language instructions and directives into machine instruc tions Introduction to SDEs Compilers and assemblers are used to produce relocatable object files Each of these files cannot be executed individually for they require further processing An executable program consists of one or more relocatable object files It is produced by a link editor One relocatable object file may reference routin
35. and link them with each other to create an executable program These object files are called relocatable object files because they contain references to symbols that have not yet been connected with their definitions have not yet been assigned addresses in memory We also suggested that this command line would arrange for the standard C library functions that you have called in your program to be linked with your executable automatically The standard C library is in this default arrangement a shared object called libc so which means that the functions you have called will be linked with your program at run time There are some exceptions A number of C library functions have been left out of Libc so by design If you use one of these functions in your program the code for the function will be incorporated in your executable at link time That is the function will still be automatically linked with your program only statically rather than dynamically The standard C library contains the system calls described in Section 2 man pages and the C language functions described in Section 3 Subsections 3C and 3S man pages Now let s look at the formal basis for this arrangement 1 By convention shared objects or dynamically linked libraries are designated by the prefix 1ib and the suffix so archives or statically linked libraries are designated by the prefix 1ib and the suffix a libc so then is the shared object version of the standa
36. being processed by analyze none of the reports will be able to include accurate file names or line numbers Generally the file name will be the null string and the line num bers will be 0 if the information was not present in the object file 3 Project Control Replace with Part 3 tab Compilation Systems Volume 1 Tools Part 3 Project Control Part 3 Project Control Part 3 Project Control Chapter 12 Introduction to Project Control ooocncninnnncnocnononncnnconocncnnccnncnns 12 1 Chapter 13 Managing File Interactions with make esse 13 1 Chapter 14 Tracking Versions with SCCS sess 14 1 Compilation Systems Volume 1 Tools 12 Introduction to Project Control Trtroduction n Oe IG A SMR SR Re ee 12 1 Compilation Systems Volume 1 Tools Introduction Introduction to Project Control 12 Introduction to Project Control A software project consists of one or more products Each product consists of one or more files including the following Program files for example source object and executables for one or more platforms Documentation files for example design and functional specifications release notes man pages user and reference manuals and reference cards Training files for example student guides instructor guides and example source files Testing files for example third party and internally developed test suites and programs supplied wi
37. but it presumes that all Fortran common blocks are strictly standard conforming Unexpected results could be obtained if this option is used and nonstandard Fortran common block extensions are present Qsymbolic Same as Bsymbolic Qwarn mult init Warns if a Fortran common block is multiply initialized If a particular byte in the common block is multiply initialized the last initialized value of the byte is selected Without this option no warning is produced and all initialization values of the byte are OR ed together OQ y n Same as d yIn V Output a message giving information about the version of 1d being used X Do not look in alternate search paths for libraries An error message will be generated if the libraries cannot be located in the specified search path s YP dirlist Change the default directories used for finding libraries dirlist is a colon separated path list The environment variable LD_LIBRARY_PATH may be used to specify library search directories In the most general case it will contain two directory lists separated by a semicolon dirlist1 dirlist2 If 1d is called with any number of occurrences of L as in ld Lpathl Lpathn then the search path ordering is dirlistl pathl pathn dirlist2 LIBPATH LD LIBRARY PATH is also used to specify library search directories to the dynamic linker at run time That is if LD_LIBRARY_PATH exists in the environment the dynamic linker wil
38. can be used to simulate parsers with multiple end markers or context sensitive syntax checking Accessing Values in Enclosing Rules An action may refer to values returned by actions to the left of the current rule The mechanism is simply the same as with ordinary actions followed by a digit 7 26 Parsing with yacc adj noun verb adj noun look at the sentence THE YOUNG YOUNG DOG DOG CRONE if 0 YOUNG void printf what n CRONE In this case the digit may be 0 or negative In the action following the word CRONE a check is made that the preceding token shifted was not YOUNG Obviously this is only possible when a great deal is known about what might precede the symbol noun in the input Nevertheless at times this mechanism prevents a great deal of trouble especially when a few combinations are to be excluded from an otherwise regular structure Support for Arbitrary Value Types By default the values returned by actions and the lexical analyzer are integers yacc can also support values of other types including structures In addition yace keeps track of the types and inserts appropriate union member names so that the resulting parser is strictly type checked The yacc value stack is declared to be a union of the various types of values desired You declare the union and associate union member names with each token and non terminal symbol having a va
39. causing state 20 to be pushed onto the stack and become the current state In effect the reduce action turns back the clock in the parse popping the states off the stack to go back to the state where the right hand side of the rule was first seen The parser then behaves as if it had seen the left side at that time If the right hand side of the rule is empty no states are popped off the stacks The uncovered state is in fact the current state The reduce action is also important in the treatment of user supplied actions and values When a rule is reduced the code supplied with the rule is executed before the stack is adjusted In addition to the stack holding the states another stack running in parallel with it holds the values returned from the lexical analyzer and the actions When a shift takes place the external variable yy 1val is copied onto the value stack After the return from the user code the reduction is carried out When the goto action is done the external variable yyval is copied onto the value stack The pseudo variables 1 2 and so on refer to the value stack The other two parser actions are conceptually much simpler The accept action indicates that the entire input has been seen and that it matches the specification This action appears only when the lookahead token is the end marker and indicates that the parser has successfully done its job The error action on the other hand represents a place where the parser can
40. consider stat IF cond stat IF cond stat ELSE stat which is a fragment from a programming language involving an if then else state ment In these rules IF and ELSE are tokens cond is a non terminal symbol describing conditional logical expressions and stat is a non terminal symbol describing state ments The first rule will be called the simple if rule and the second the if else rule These two rules form an ambiguous construction because input of the form TE GA GCI xpo SERS 3G CZ ge Side ELSE 32 can be structured according to these rules in two ways IF C1 IF C2 S1 ELSE S2 or IF Cl IF C2 S1 ELSE 82 where the second interpretation is the one given in most programming languages having this construct each ELSE is associated with the last preceding un ELSE d IF In this example consider the situation where the parser has seen LBS UC Cl Dp EBS C 2 ST and is looking at the ELSE It can immediately reduce by the simple if rule to get IF Cl stat and then read the remaining input Parsing with yacc ELSE S2 and reduce IF ET stat ELSE S2 by the if else rule This leads to the first of the above groupings of the input On the other hand the ELSE may be shifted S2 read and then the right hand portion of IF Cl IF C2
41. dozi rTrA SI Difference or Zero Immediate 601 only PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC RS 6000 i Syntax of Operands Description POWER Mnemonic Mnemonic dsa Disable Supervisor Access 602 only eciwx 1T rA rB External Control In Word Indexed optional not on 602 ecowx IS rA rB External Control Out Word Indexed optional not on 602 eieio Enforce In order Execution of I O eqv rA rS rB Equivalent esa Enable Supervisor Access 602 only extldi rA rS n b Extract and Left Justify Doubleword Immediate Same as rldicr rA rS b n 1 extlwi rA rS n b Extract and Left Justify Word Immediate Same as rlwinm rA rS b 0 n 1 extrdi rA rS n b Extract and Right Justify Doubleword Immediate Same as rldicl rA rS b n 64 n extrwil rA rS n b Extract and Right Justify Word Immediate Same as rlwinm rA rS b n 32 n 31 extsb rA rS Extend Sign Byte extsh rA rS Extend Sign Halfword exts extsw rA rS Extend Sign Word fabs fT fB Floating Absolute Value fadd s fT fA fB Floating Add double precision not on 602 fa fcfid fT fB Floating Convert From Integer Doubleword fempo crf T fA fB Floating Compare Ordered 7 crfT defaults to crfO fcmpu crf T fA fB Floating Compare Unordered crfT defaults to crfO fctid fT fB Floating Convert to Integer Doubleword fctidz fT fB Floating Convert to Integer Doubleword with round toward Zero fctiw
42. fp_spec_exec The following C function could be assembled to the assembly source code shown below Assembly source that is accepted by the assembler is used in this example sub i qu AA OA printf the value of i d An i version 02 00 fil exampl c data align 3 lit_lab string text align global sub type size addi mflr stw Sub sub line 3 cmpwi ble line 4 lis ori bl L6 lwz mtlr addi blr Sub sub end QL12 section word word word word word word Position Independent Code Assembly Syntax Assembler and Assembly Language the value of i d n 000 sub sub function sub sub sub end sub FT EL 80 r13 return address r13 88 r1 mr r4 r3 crf1 r4 0 crfl1 L6 r3 uhil6 lit lab r3 r3 lol6 lit lab printf r13 88 r1 r13 r1 r1 80 Edesa x 0x42 0x1 sub_sub_ L12 0x10000021 0x50 0x8 Oxfffffff0 The assembly language is extended to support position independent code which is used in dynamic linking See Chapter 4 Link Editor and Linking for information on dynamic linking and shared object files The following expressions are explained and some of these extensions are used in the example that follows The assembler requires that Q be used in these expressions e g s got The is used in the explanations that follow 2 21 Compilation Systems Volume 1 Tools Example 2 22 S got p
43. get s abc which normally retrieves the latest version of s abc from the SCCS file tree trunk and produces for example on the standard output 12 3 67 lines No id keywords cm7 meaning version 1 3 of s abc was retrieved assuming 1 3 is the latest trunk delta it has 67 lines of text and no ID keywords were substituted in the file The g file namely file abc is given access permission mode 444 read only for owner group and other This particular way of using get is intended to produce g files only for inspection compilation or copying for example It is not intended for editing making deltas When several files are specified the same information is output for each one For exam ple 14 9 Compilation Systems Volume 1 Tools ID Keywords get s abc s xyz produces s abc 123 67 lines No id keywords cm S XyZ 1 257 85 lines No id keywords cm In generating a g file for compilation it is useful to record the date and time of creation the version retrieved the module s name and so on in the g file itself This information appears in a load module when one is eventually created SCCS provides a convenient mechanism for doing this automatically Identification ID keywords appearing any where in the g file are replaced by appropriate values according to the definitions of those ID keywords The format of an ID keyword is an uppercase letter enclosed by percent signs For example oe
44. in the code labeled normal processing The function yyless n lets you specify the number of matched characters on which an action is to be performed only the first n characters of the expression are retained in yytext Subsequent processing resumes at the nth 1 character Suppose you are again in the code deciphering business and the idea is to work with only half the characters in a sequence that ends with a certain one say upper or lowercase Z The code you want might be a yA Y Zz yyless yyleng 2 process first half of string Finally the function REJECT lets you more easily process strings of characters even when they overlap or contain one another as parts REJECT does this by immediately jumping to the next rule and its specification without changing the contents of yytext If you want to count the number of occurrences both of the regular expression snapdragon and of its subexpression dragon in an input text the following will do 6 11 Compilation Systems Volume 1 Tools Definitions 6 12 snapdragon countflowers REJECT dragon countmonsters As an example of one pattern overlapping another the following counts the number of occurrences of the expressions comedian and diana even where the input text has sequences such as comediana comedian comiccount REJECT diana princesscount Note that the actions here may be co
45. link editor by a definition of a global symbol That is if a defined global symbol exists the appearance of a weak symbol with the same name will not cause an error To illustrate this let s look at our own implementation of the standard C library This library provides services that users are allowed to redefine and replace At the same time however ANSI C defines standard services that must be present on the system and cannot be replaced in a strictly conforming program fread for example is an ANSI C library function the system function read is not So a conforming program may redefine read and still use fread in a predictable way Mapfiles Link Editor and Linking The problem with this is that read underlies the read implementation in the standard C library A program that redefines read could confuse the fread implementation To guard against this ANSI C states that an implementation cannot use a name that is not reserved to it That s why we use read note the leading under score to implement fread in the standard C library Now suppose that a program you have written calls read If your program is going to work a definition for read does exist in the C library It is identical to the definition for read and contained in the same object file Suppose further that another program you have written redefines read as it has every right to do under ANSI C this same program calls fr
46. list number of the line individually or invoke the editor for all the lines automatically by pressing Ctrl e Using cscope to make this type of change assures that none of the functions you need to edit will be overlooked 9 17 Compilation Systems Volume 1 Tools Changing the Value of a Variable The value of cscope as a browser becomes apparent when you want to see how a proposed change will affect your code If you want to change the value of a variable or preprocessor symbol use the first menu item Find this C symbol to obtain a list of references that will be affected Then use the editor to examine each one This will help you predict the overall effects of your proposed change You can also use this menu to ver ify that your changes have been made Technical Tips This section describes certain problems that may arise when you use escope and how to avoid them Unknown Terminal Type You may see the error message Sorry I don t know anything about your term terminal If this message appears your terminal may not be listed in the Terminal Information Utilities terminfo database that is currently loaded Make sure you have assigned the correct value to TERM If the message reappears try reloading the Terminal Information Utilities You may also see Sorry I need to know a more specific terminal type than unknown If this message appears set and export the TERM as described in Step 1 Set Up the Envi ro
47. o O number r R number os T file W Performance Analysis Generate a profiling report showing the number of cache misses due to data accesses loads and stores The report is sorted in decreasing order of secondary cache misses Limit the number of data access cache statistics printed Use of N implies n This option acts much like the B option above Generate a profiling report showing the number of cache misses due to instruction fetches The report is sorted in decreasing order of secondary cache misses Limit the number of instruction access cache statistics printed Use of O implies o This option acts much like the B option above Generate a profiling report showing the time spent in each routine This report is generated by adding up all the time in the individual basic blocks Restrict the routine report to only the first number routines This option acts much like the B option above and will accept an absolute number or a percentage Use of R implies r Print the header information from each profile data set This may be used by itself to determine how many sets of data are in a profile data file in order to determine which sets to examine with the d option Total all the data sets and print the total statistics in any of the reports requested Normally this option suppresses the generation of any reports on individual data sets and only the totals are printed The a
48. the command sequence for the rule r o is used If a command is generated by using one of these suffixing rules the macro is given the value of the stem everything but the suffix of the name of the file to be made and the macro lt is the full name of the dependent that caused the action The order of the suffix list is significant since the list is scanned from left to right The first name formed that has both a file and a rule associated with it is used If new names are to be appended the user can add an entry for SUFFIXES in the description file The dependents are added to the usual list A SUFF IXES line without any dependents deletes the current list It is necessary to clear the current list if the order of names is to be changed make uses a table of suffixes and a set of transformation rules to supply default dependency information and implied commands The default suffix list in order is as fol lows o Object file c C source file c SCCS C source file y yacc C source grammar y SCCS yacc C source grammar 1 lex C source grammar 1 SCCS lex C source grammar s Assembler source file S SCCS assembler source file sh Shell file 13 9 Compilation Systems Volume 1 Tools 13 10 sh SCCS shell file h Header file hr SCCS header file f Fortran source file r SCCS Fortran source file C C source file C SCCS C source file Y yacc C source grammar Y SCCS yacc C so
49. unget 1 Undoes the effect of a get e prior to the file being deltaed delta 1 Applies deltas changes to SCCS files and creates new versions Tracking Versions with SCCS admin 1 Initializes SCCS files manipulates their descriptive text and controls delta creation rights prs 1 Prints portions of an SCCS file in user specified format sact 1 Prints information about files that are currently out for editing help 1 Gives explanations of error messages rmdel 1 Removes a delta from an SCCS file allows removal of deltas created by mistake cdc 1 Changes the commentary associated with a delta what 1 Searches any UNIX system file s for all occurrences of a special pattern and prints out what follows it useful in finding identifying information inserted by the get command sccsdiff 1 Shows differences between any two versions of an SCCS file comb 1 Combines consecutive deltas into one to reduce the size of an SCCS file val 1 Validates an SCCS file The get Command The get command creates a file that contains a specified version of an SCCS file The version is retrieved by beginning with the initial version and then applying deltas in order until the desired version is obtained The resulting file called a g file for gotten is created in the current directory and is owned by the real user The mode assigned to the g file depends on how the get command is used The most common use of get is
50. 1 define b 2 define at at va vb gives the result a b because the quotes are put back on the arguments when at is evaluated is replaced by the number of arguments in the subsequent invocation define sharp S sharp 1 2 3 gives the result 3 sharp gives the result 1 and sharp gives the result 0 The built in shift returns all but its first argument The other arguments are quoted and pushed back onto the input with commas in between The simplest case shift 1 2 3 gives 2 3 As with you can delay the expansion of the arguments by quoting them so m4 Macro Processor define a 100 define b 200 shift a b gives the result b because the quotes are put back on the arguments when shift is evaluated Arithmetic Built Ins File Inclusion m4 provides three built in macros for doing integer arithmetic incr increments its numeric argument by 1 decr decrements by 1 To handle the common programming situation in which a variable is to be defined as one more than N you would use define N 100 define N1 incr N N1 is defined as one more than the current value of N The more general mechanism for arithmetic is a built in called eval which is capable of arbitrary arithmetic on integers Its operators in decreasing order of precedence are unary x me ES gt gt ES amp amp amp Parenthese
51. 2 In a reduce reduce conflict the default is to reduce by the earlier grammar rule in the yace specification Rule 1 implies that reductions are deferred in favor of shifts when there is a choice Rule 2 gives the user rather crude control over the behavior of the parser in this situation but reduce reduce conflicts should be avoided when possible Conflicts may arise because of mistakes in input or logic or because the grammar rules while consistent require a more complex parser than yace can construct The use of actions within rules can also cause conflicts if the action must be done before the parser can be sure which rule is being recognized In these cases the application of disambiguating rules is inappropriate and leads to an incorrect parser For this reason 7 13 Compilation Systems Volume I Tools 7 14 yacc always reports the number of shift reduce and reduce reduce conflicts resolved by rules and 2 above In general whenever it is possible to apply disambiguating rules to produce a correct parser it is also possible to rewrite the grammar rules so that the same inputs are read but there are no conflicts For this reason most previous parser generators have considered conflicts to be fatal errors Our experience has suggested that this rewriting is somewhat unnatural and produces slower parsers Thus yace will produce parsers even in the presence of conflicts As an example of the power of disambiguating rules
52. 2 8 2 16 double 2 16 extern 2 16 file 2 8 2 18 float 2 15 gloabl 2 16 half 2 14 ident 2 18 2 19 local 2 17 previous 2 14 sbyte 2 14 section 2 13 set 2 16 shalf 2 15 short 2 14 size 2 18 string 2 16 text 2 13 type 2 18 uahalf 2 15 uaword 2 15 ubyte 2 14 uhalf 2 15 vbyte 2 14 version 2 4 2 6 2 7 2 18 weak 2 17 zero 2 12 directive bss 2 17 word 2 15 Directory tmp 2 2 var tmp 2 2 Directory functions 16 7 Directory Use Functions 16 7 Diretive Index 3 Compilation Systems Volume 1 Tools assembler 2 6 dis 1 1 5 Disassembler 1 5 double directive 2 16 dump 1 1 5 Dumper 1 5 Duplicating loop exit tests 20 18 20 22 Duplicating partially constant conditional branches 20 11 20 12 DWARE 1 5 1 6 DWARF Access Library 22 61 DWARF address ranges tables 22 16 DWARF debugging 22 16 DWARF line number information 22 16 DWARF name lookup tables 22 17 DWARF version 2 draft 5 specification 22 61 Dwarf base encoding 22 62 dwarf dealloc 22 62 Dwarf Error error 22 62 Dwarf Half tagbuf 22 62 dwarf isbasetype 22 62 Dwarf Signed dwarf modtags 22 62 Dwarf Type 22 62 Dwarf Type typ 22 62 Dynamic link 1 6 dynamic linking 4 8 implementation 4 17 4 18 22 27 22 45 EDITOR environment variable 9 2 9 18 ELF 1 5 1 6 2 1 ELF see also object files 22 1 ELF file functions 16 17 16 18 ELFlibrary 16 3 Eliminating unreachable code 20 10 20 11 Encryption functions 16 52 Environment variable EDITOR 9 2 9 18 LD
53. 25 1 Purpose and Scope conocerme e le te ms 25 1 XX Illustrations Screens Contents Definitions u ee ee EE a Bact 25 2 OYEIVIEW cid in shes dda peak As Aric 25 2 Type Definitions cele sh res 25 2 General Description tal ee et De eet ses 25 2 Scalar Types css eem ee ee bead pac 25 3 Aggregate Types ido 25 3 Location Record veis cee cee 2530 ce e en 25 4 Location Description 0 0 eee cece eee 25 4 Element Listes 2 30 eee ds eR 25 4 Subscript Bounds Information 0 0 0 0 02 cee ee eee ee 25 5 Data Block er tocea Seed Se a e Be see 25 5 Opaque Ty DOS ir ee en e tie Seale eet esu 25 5 Erot Handling oeei aned mee RR REVUE UR DER a HORAE 25 6 Memory Management 0 cee her 25 8 Read only Properties ooooooocooooooccoo eh 25 8 Storage Deallocation 0 56 eee eee e RR a 25 8 Functional Interface u Re ERR UE RR ead 25 9 Initialization Operations leleleeeeeee Ie 25 9 Debugging Information Entry Delivery Operations 25 10 Debugging Information Entry Query Operations lesse esee 25 12 Array Subscript Query Operations llle eee 25 15 Type Information Query Operations 00 0 0 een 25 16 Attribute Form Queries 0 00 0 n eens 25 16 Line Number Operations 0 0 c eee cece eh 25 18 Global Name Space Operations 00 0 cee eee ee eee 25 20 Utility Operations 4i di ie hd REP RR Det ee 25
54. 4 Compressor 1 5 const 4 20 Constant propagation 20 11 Control functions 16 46 Control level functions 16 51 Controlling compiler optimizations 20 3 20 8 Copy propagation 20 12 20 14 20 15 20 16 Expression 20 14 Copy propagation Constant Constant 20 14 Copy propagation Variable Variable 20 14 Copy variables 20 12 20 15 20 16 cpp 1 1 4 cprs 1 1 5 Cross reference 1 5 cscope 1 1 5 9 1 9 19 cscope 1 command line 9 2 9 10 9 13 cscope 1 environment setup 9 2 9 18 9 19 cscope 1 environment variable 9 13 cscope 1 usage examples 9 1 9 10 9 14 9 18 ctrace 1 1 4 cxref 1 1 5 D data directive 2 11 2 13 data representation 22 2 data segment see also object files 4 17 4 18 4 19 4 20 4 21 Data structures functions 16 31 Date and time functions 16 34 Dead code elimination 20 12 20 13 20 14 Debugger object 1 4 symbolic 1 3 1 4 Debugging optimized code 20 32 20 33 20 34 20 35 Debugging with arbitrary record format 1 5 1 6 def directive 2 8 2 16 Delimeter comment 2 5 delta 1 14 3 14 8 14 17 14 19 DES Algorithm Access 16 41 16 52 Devices functions 16 12 Directive 2 1 lign 2 12 ascii 2 16 asciiz 2 16 bss 2 17 byte 2 14 comm 2 17 data 2 13 def 2 16 Index double 2 16 extern 2 16 file 2 18 float 2 15 globl 2 16 Aint 2 15 long 2 15 org 2 12 Set 2 16 short 2 14 space 2 12 text 2 13 vbyte 2 14 word 2 14 align 2 12 2 17 byte 2 14 comm 2 17 data 2 11 2 13 def
55. 6 1 Compilation Systems Volume I Tools 6 2 lex lex 1 where lex 1 is the file containing your lex specification The name lex 1 is the favored convention but you may use whatever name you want Keep in mind though that the 1 suffix is a convention recognized by other UNIX system tools in particular make The source code is written to an output file called lex yy c by default That file contains the definition of a function called yylex that returns 1 whenever an expression you have specified is found in the input text 0 when end of file is encountered Each call to yylex parses one token When yylex is called again it picks up where it left off Note that running lex on a specification that is spread across several files lex lexl 1 lex2 1 lex3 1 produces one lex yy c Invoking lex with the t option causes it to write its output to stdout rather than lex yy c so that it can be redirected lex t lex 1 gt lex c Options to lex must appear between the command name and the file name argument The lexical analyzer code stored in lex yy c or the c file to which it was redirected must be compiled to generate the executable object program or scanner that performs the lexical analysis of an input text The lex library 1ib1 a supplies a default main that calls the function yylex so you need not supply your own main The library is accessed by specifying 1ib1 with the 1 option to ce cc lex yy
56. 991 Move From Sampled Instruction Address Register 604 e 620 only Supervisor Level Same as mfspr rT 955 Move From Single Precision Tag Register 602 only Supervisor Level Same as mfspr rT 1021 Move From Special Purpose Register Supervisor Level if SPR 0 Move From Special Purpose Register General n Supervisor Level Same as mfspr rT 272 n Move From Segment Register Supervisor Level Move From Segment Register Indirect mfsri Supervisor Level Move From Save Restore Register 0 Supervisor Level Same as mfspr rT 26 Move From Save Restore Register 1 Supervisor Level Same as mfspr rT 27 Move From Time Base lower not on 601 Note that 64 bit implementations get all 64 bits with this one instruction Same as mftb rT 268 Move From Time Base Lower not on 601 64 bit Same as mftb rT 268 Move From Time Base Upper not on 601 64 bit Same as mftb rT 269 Move From Time Control Register 602 only Supervisor Level Same as mfspr rT 984 Move From Thermal 1 750 only Supervisor Level Same as mfspr rT 1020 3 14 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC Mnemonic Syntax of Operands RS 6000 Description POWER Mnemonic mfthrm2 mfthrm3 mfummcrO mfummcr1 mfupmcl mfupmc2 mfupmc3 mfupmc4 mfusia mfxer mtasr mtbatl mtbatu IT IT IT IT IT IT IT IT IT IT T rA IS n rS n rS
57. AA BEGIN BB BEGIN CC n BEGIN 0 lt AA gt magic prunt5irst BB magic printf second CC magic pam Behr You may want to use your own routines in lex for much the same reason that you do so in other programming languages Action code that is to be used for several rules can be written once and called when needed As with definitions this can simplify the writing and reading of programs The function put in tabl to be discussed in Using lex with yacc on page 6 15 is a good candidate for the user routines section of a lex specification Another reason to place a routine in this section is to highlight some code of interest or to simplify the rules section even if the code is to be used for one rule only As an example consider the following routine to ignore comments in a language like C where comments occur between and Lexical Analysis with lex 2 static skipcmnts ol Skipcmnts io rest f rules Sta Skipcmnts for while input NUCA Ake Uy unput yytext yyleng 1 else return There are three points of interest in this example First the unput c macro putting back the last character read is necessary to avoid missing the final if the comment ends with a In this case eventually having read a the scanner finds that the next character is not the terminal and must read some more Second the expression yytext yyleng 1 pic
58. Api tidie Are 5 8 System Command de 5 8 Conditionals a ia 5 8 String Manipulation 0 2 0 0 0 ee eee eee 5 9 PHONE 0253 teu E Vane lal ea ne Saale AS Bes 5 10 Compilation Systems Volume 1 Tools 5 m4 Macro Processor Introduction m4 is a general purpose macro processor that can be used to preprocess C and assembly language programs among other things Besides the straightforward replacement of one string of text by another m4 lets you perform nteger arithmetic Fileinclusion Conditional macro expansion String and substring manipulation You can use built in macros to perform these tasks or define your own macros Built in and user defined macros work exactly the same way except that some of the built in macros have side effects on the state of the process A list of built in macros appears on the m4 1 page The basic operation of m4 is to read every legal token string of ASCII letters and digits and possibly supplementary characters and determine if the token is the name of a macro The name of the macro is replaced by its defining text and the resulting string is pushed back onto the input to be rescanned Macros may be called with arguments The arguments are collected and substituted into the right places in the defining text before the defining text is rescanned Macro calls have the general form name argl arg2 argn If a macro name is not immediately followed by a left parenthesis it is a
59. BIND NOW 4 16 22 47 22 55 LD LIBRARY PATH 4 7 4 14 4 36 22 52 LD RUN PATH 4 7 4 15 4 36 MAKEFLAGS 13 18 PARALLEL 13 5 13 17 STATIC LINK 4 8 TERM 9 2 TMPDIR 2 2 9 13 VIEWER 9 2 VPATH 9 2 9 13 exceptions 22 61 Executable and linking format 1 5 1 6 2 1 executable files 22 1 Index 4 Executable program 1 3 Expression optimizations 20 10 20 16 20 17 Expressions Optimizing 20 16 Propagating 20 14 Simplifying 20 16 extensions 22 61 extern directive 2 16 f77 1 1 4 File var adm utmpx 16 16 File etc group 16 15 etc mnttab 16 14 etc passwd 16 14 etc shadow 16 15 etc vfstab 16 13 var adm utmp 16 16 var adm wtmp 16 16 var adm wtmpx 16 16 common object format 1 5 object 1 5 relocatable object 1 3 2 1 2 2 File Access Functions 16 5 16 11 16 12 File and I O status functions 16 6 file directive 2 8 2 18 File functions 16 7 File Status Functions 16 6 File systems tables file functions 16 13 File tree functions 16 32 float directive 2 15 Floating point 1 7 Floating point functions 16 41 Floating point operations 17 1 17 12 compares 17 12 control bits 17 7 data representation 17 1 17 6 data types and formats 17 2 denormalized numbers 17 3 double extended 17 11 double precision 17 2 exception handling 17 7 17 9 exceptions 17 7 floating point to integer conversion 17 11 IEEE requirements 17 11 infinities 17 5 infinities I O 17 12 language mappings 17 3 maximum and minimum values 17 4 NaNs 17 5 N
60. C library The cc command will automatically direct the link editor to search 1ibc a if you turn off the dynamic linking default with the Zlink static option cc Zlink static filel c file2 c file3 c Copies of the object files in 1ibc a that resolve still unresolved external references in your program will be incorporated in your executable at link time If you need to point the link editor to standard libraries that are not searched automatically you specify the 1 option explicitly on the cc command line As we have seen 1x directs the link editor to search the shared object 1ibx so or the archive library libx a So if Link Editor and Linking your program calls the function sin for example in the standard math library 1ibm the command cc filel c file2 c file3 c lm will direct the link editor to search for usr lib libm so and if it does not find it lib libm a to satisfy references to sin in your program Because the compilation system supplies shared object versions only of libc and libdl the above command will direct the link editor to search libm a unless you have installed a shared object version of 1ibm in the standard place Note that because we did not turn off the dynamic linking default with the Zlink static option the above command will direct the link editor to search libc so rather than 1ibc a You would use the same command with the Zlink static option to link your program statically with libm a and li
61. Care must be taken to make sure that all token numbers are distinct For historical reasons the end marker must have token number 0 or be negative You can not redefine this token number Thus all lexical analyzers should be prepared to return 0 or a negative number as a token upon reaching the end of their input As noted in Chapter 6 Lexical Analysis with lex lexical analyzers produced by lex are designed to work in close harmony with yacc parsers The specifications for these lexical analyzers use regular expressions instead of grammar rules lex can be used to produce quite complicated lexical analyzers but there remain some languages that do not fit any theoretical framework and whose lexical analyzers must be crafted by hand Parsing with yacc Parser Operation yacc turns the specification file into a C language procedure which parses the input according to the specification given The algorithm used to go from the specification to the parser is complex and will not be discussed here The parser itself though is relatively simple and understanding its usage will make treatment of error recovery and ambiguities easier The parser produced by yacc consists of a finite state machine with a stack The parser is also capable of reading and remembering the next input token called the lookahead token The current state is always the one on the top of the stack The states of the finite state machine are given small integer labels
62. File Interactions with make Your make file for the program might look like this filel 1 c filel m4 m4 DV ER 1 filel m4 gt filel l c filel 2 c filel m4 m4 DV ER 2 filel m4 gt filel 2 c You can use the U option to undefine VER If filel m4 contains if V if V 1 Bo a do_something do something f ifndef VER do_something then your makefile would contain file0 0 c filel m4 m4 UV ER filel m4 gt filel 0 c filel 1 c filel m4 m4 DV ER 1 filel m4 gt filel l c filel 2 c filel m4 m4 m4 Macros Defining Macros DV ER 2 filel m4 gt filel 2 c The primary built in m4 macro is define which is used to define new macros The following input 5 2 Quoting m4 Macro Processor define name stuff causes the string name to be defined as stuff All subsequent occurrences of name will be replaced by stuff The defined string must contain only ASCII alphanumeric or printable supplementary characters and must begin with a letter or printable supplementary character underscore counts as a letter The defining string is any text that contains balanced parentheses it may stretch over multiple lines As a typical example define N 100 if i gt N defines N to be 100 and uses the symbolic constant N in a later if statement As noted the left parenthesis must immediately follow the word define to signal
63. R L mB 1 1 successor R L B S Branch successor R L B S R L mB 1 1 Concurrent Edits of Same SID Under normal conditions more than one get e for the same SID is not permitted That is delta must be executed before a subsequent get e is executed on the same SID Multiple concurrent edits are allowed if the 3 flag is set in the SCCS file Thus get e s abc dd new delta 1 2 5 lines may be immediately followed by 14 15 Compilation Systems Volume 1 Tools get e s abc Ll new delta 1 1 1 1 5 lines without an intervening delta In this case a delta after the first get will produce delta 1 2 assuming 1 1 is the most recent trunk delta and a delta after the second get will produce delta 1 1 1 1 Key letters that Affect Output 14 16 get p causes the retrieved text to be written to the standard output rather than to a g file In addition all output normally directed to the standard output such as the SID of the version retrieved and the number of lines retrieved is directed instead to the standard error get p is used for example to create a g file with an arbitrary name as in get p s abc gt arbitrary file name get s suppresses output normally directed to the standard output such as the SID of the retrieved version and the number of lines retrieved but it does not affect messages nor mally directed to the standard error get s is used to prevent non diagnostic messages from appearing o
64. Res 16 12 File Systems Table File lees 16 13 File Systems Mount Table File 0 000000 e eee ee 16 14 P ssword Eile e eet vd aet C C RC 16 14 Shadow Password File 2 2 0 0 cee eee ee 16 15 Gro p Eil 3 2 ee ee ne 16 15 User and Accounting Information Files oooooooooooooooo o 16 16 ELF Elles een A te a 16 17 DWARF Debugging Information eese 16 18 Shared Objects 2i eee ee eee eno tr otras 16 22 Temporary Files eres eve en DR ae 16 22 Stringsand Characters usce ek e e es 16 22 String Manipulati0N o ooooocooococcoco eee eee 16 23 Wide String Manipulation 0 0 0 0 eee 16 24 Character Test 5 2 e A I RR 16 25 Wide Character Test eked wae eS oie e tes 16 26 Character Translation llle ee 16 26 Multibyte and Wide Characters 0 0 0 cece eene 16 27 Regular Expression and Pattern Matching 005 16 27 MEMORY hts aa ede ep ar aret atto di m a PR Ar Rh 16 28 Memory Manipulation 0 0 0 eee eee 16 28 Memory Allocation 16 29 Memory Control icon 2 3 2 Se ee ee eee a ee REY ee 16 30 Shared Memory es eer eto eec a SOA ey SEA ne ts 16 30 Data Structures ic ee oe ee a ds ee 16 31 Tables 22 ie et eee etn derer ett ee ee 16 31 Hash Tables ai en Pu Ie des ae EUR 16 31 File Trees ie cp aei eat nee en 16 32 Binary Trees uel M oe hates ook HR ea REED Es 16 32 Message Qu amp ues uie e eer dp ac oca e Se
65. SI ELSE S2 can be reduced by the if else rule to get IF Cl stat which can be reduced by the simple if rule This leads to the second of the above groupings of the input which is usually the one desired Once again the parser can do two valid things there is a shift reduce conflict The application of disambiguating rule 1 tells the parser to shift in this case which leads to the desired grouping This shift reduce conflict arises only when there is a particular current input symbol ELSE and particular inputs such as TPS CC x1 EE iy EZ e 54 have already been seen In general there may be many conflicts and each one will be associated with an input symbol and a set of previously read inputs The previously read inputs are characterized by the state of the parser The conflict messages of yacc are best understood by examining the v output For example the output corresponding to the above conflict state might be 23 shift reduce conflict shift 45 reduce 18 on ELSE state 23 Siecle 8 COn Es oa 18 Stat ser DE nE eos F Stat ELEC stat ELSE shitt 45 reduce 18 where the first line describes the conflict giving the state and the input symbol The ordinary state description gives the grammar rules active in the state and the parser actions Recall that the underscore marks the portion of the grammar rules that has been seen Thus in the example in state 23 the parser has seen in
66. SIDs automatically Creating an SCCS File with admin Suppose you have a file called lang that is simply a list of five programming language names Custody of your lang file can be given to SCCS using the admin for administer command The following creates an SCCS file from the lang file admin ilang s lang All SCCS files must have names that begin with s hence s lang The i key letter together with its value lang means admin is to create an SCCS file and initialize it with the contents of the file lang The admin command replies No id keywords cm7 This is a warning message that may also be issued by other SCCS commands Ignore it for now Its significance is described later under the get command in SCCS Commands on page 14 8 In the following examples this warning message is not shown although it may be issued Remove the lang file It is no longer needed because it exists now under SCCS as s lang rm lang Retrieving a File with get 14 2 The command get s lang retrieves the latest version of s lang and prints Eh 5 lines This tells you that get retrieved version 1 1 of the file which is made up of five lines of text Tracking Versions with SCCS The retrieved text is placed in a new file called lang That is if you list the contents of your directory you will see both lang and s lang The get s lang command creates lang a file meant for viewing read only not for making changes
67. Section FP Speculative Execution Use fp spec exec 22 22 String Table pe sun ee HERE pare ed etches 22 22 String Table Indexes lesse 22 22 Symbol Binding ELF32 ST BIND 0 00 20 22 24 Symbol Types ELF32 ST TYPE 0004 22 25 Symbol Table Entry Index 0 eese 22 26 Relocation Types iub t he Roe e RR Re tp aces 22 32 Segment Types p type 0 0 et o e nennen 22 37 Segment Flag Bits p flags 0 00 0 0c eee eee 22 39 Segment Permissions lees 22 39 Text Segment soit O EE en 22 40 Data Segment eco 2 8 D ye eae Se tote a 22 40 Note Information idad Ma ete Ce e 22 41 Example Note Segment 00 0 c eee eee eee 22 42 Executable File zs eich tte ee bier os 22 43 Program Header Segments 0 0 00 c cee eee eee ee 22 43 Process Image Segments 0 0 cece eee eee 22 44 Example Shared Object Segment Addresses 22 45 Dynamic Array Tags d tag 22 48 GOTP Binding Entry Stack Frame 005 22 56 GOTP Binding Entiy u 2 2 828 et dente in 22 56 GOTP Binding Helper 0 00 cece eee ee eee 22 57 PEF ENUY tido a c e een ee eh 22 59 SYMBOL io 2 eeuebne em meter te ren 22 60 Tag Names e E tete ee e PCR tac 24 4 Attribute Names ool Rec n RR ee 24 5 Accessibility Codes 2 ege eR ek en 24 16 Visibility Codes seem ey Dey eg e Re oe 24 16 Virtuality Codes ascii UR rata e
68. Simple A pointer was assigned to an object of an integral type that is smaller than the pointer 1 void fun 2 3 char c 4 Inte 17 5 c i 6 5 warning conversion of pointer loses bits conversion to larger integral type may sign extend incorrectly Format Compound A variable of type plain char was assigned to a variable of a larger integral type Whether a plain char is treated as signed or unsigned is implementation defined The message is issued only when lint is invoked with p and is suppressed when it is invoked with a 1 void fun 2 3 char c 0 4 short s 0 E long 1 6 l c it l s 8 conversion to larger integral type may sign extend incorrectly 6 10 17 Compilation Systems Volume 1 Tools declaration unused in block Format Compound An external variable or function was declared but not used in an inner block 1 int fun 2 3 int foo 4 int bar 5 return foo 6 declaration unused in block 4 bar declared global could be static Format Compound An external variable or function was declared global instead of static but was referenced only in the file in which it was defined The message is suppressed when lint is invoked with m file 1 c 1 int i 2 int foo return i 3 int fun return i 4 static int stfun return fun file 2 c 1 main 2 3 nt a 4 a foo 5 declared global could be st
69. Types 2 0 cc cece cece ee rhe hmm heme 2 11 Expression Valuesz ER MA Moet eae ks Ae ds RUE RATIS 2 11 Assembler Directives 0 0 0 0 ccc cence enn her 2 12 Location Counter Control lessen 2 12 Section Switching llle n 2 13 Data Initialization oce rer eS ECCL RUE RAO CP ORA ee 2 14 Symbol Definitions llle 2 16 ELF Symbol Attributes eh 2 17 Miscellaneous Operations oooococococooo eh 2 18 Summary of Directives Mnemonics leeeeeee eee eee eee 2 19 vii Compilation Systems Volume 1 Tools Example ee e a es 2 20 Position Independent Code 0 0 cee cee eens 2 21 Assembly Syntax 2 eee we DTE DR a ee en 2 21 Example 5x5 CABS ALAS be eite ato eR A A e n qe 2 22 Chapter 3 PowerPC Instruction Set Summary PowerPC Instruction Set 0 0 a E A Ea E eee 3 2 Condition Codes n ete RUE UI EU 3 25 Trap Operand slides er ees eem ei e pe Pe a 3 26 Operand Abbreviations ssseleeee e 3 26 Special Purpose Registers ens a E e 3 28 Time Base Registers scole see DR a a es 3 31 Implementation Specific and Optional Instructions 0 3 31 Chapter 4 Link Editor and Linking Intr ducti n ia A A A A He 4 1 Using the Link Edit ur da pi 4 1 Basics ot Linking ori dr as e 4 8 Default Arrangement o oocooccoococ eens 4 9 Linking with Standard Libraries 02 0 0 0 eee 4 10 Creating and Linking with Archive and Shared Object Libraries
70. a eet e 24 17 Example Address Class Codes 00 0002 nennen 24 18 Language Names 0 0 00 eee cee en 24 20 Identifier Case Codes 24 21 Inline Codes rete e e e eee 24 26 Encoding Attribute Values oooooooocoococcoccococo oo 24 34 Type Modifier Tags 0 0 0 eee eee 24 35 Array Ordering od ie bk ew ete eM Re e 24 37 Discriminant Descriptor Values eese 24 43 Tag Encodings Part 1 o oooooccccccococorc ees 24 68 Tag Encodings Part 2 0 0 ee eee 24 69 Child Determination Encodings 00000000000 24 70 Attribute Encodings Part 1 0 eee ee eee 24 70 Attribute Encodings Part 2 0 0 eee eee 24 72 Attribute Form Encodings 00 0 0c cece eens 24 73 Examples of unsigned LEB128 Encodings 24 74 Examples of signed LEB128 Encodings 24 75 Location Operation Encodings Part 1 000 24 75 Location Operation Encodings Part 2 0005 24 76 Contents Table 24 24 Base Type Encoding Values 0 00 00 0c eee eee ee 24 78 Table 24 25 Accessibility Encodings 0 0 0 cece eee eee ee 24 78 Table 24 26 Visibility Encodings 0 0 0 e cece eee 24 78 Table 24 27 Virtuality Encodings 0 e eee eee 24 79 Table 24 28 Language Encodings esee 24 79 Table 24 29 Identifier Case Encodings 00 0 24 80 Table 24 30 Calling Con
71. a file containing nulls cannot be handled because a value of O returned by input is taken to be end of file There are a number of lex routines that let you handle sequences of characters to be processed in more than one way These include yymore yyless n and REJECT Recall that the text that matches a given specification is stored in the array yytext In general once the action is performed for the specification the characters in yytext are overwritten with succeeding characters in the input stream to form the next match The function yymore by contrast ensures that the succeeding characters recognized are appended to those already in yytext This lets you do one thing and then another when one string of characters is significant and a longer one including the first is significant as well Consider a language that defines a string as a set of characters between double quotation marks and specifies that to include a double quotation mark in a string it must be preceded by a backslash The regular expression matching that is somewhat confusing so it might be preferable to write re if yytext yyleng 1 yymore else normal processing When faced with the string abc def the scanner will first match the characters abc whereupon the call to yymore will cause the next part of the string def to be tacked on the end The double quotation mark terminating the string should be picked up
72. a successful search you have several options You may want to change the lines or examine the code surrounding it in the editor Or if cscope has found so many lines that a list of them will not fit on the screen at once you may want to look at the next part of the list You can even filter out unwanted lines from the list cscope has found The following table shows the commands available after cscope has found the specified text Table 9 2 Commands for Use after Initial Search 1 9 space bar Ctrl v Ctrl e gt gt gt edit the file referenced by this line the number you type corresponds to an item in the list of lines printed by cscope display next set of matching lines display next set of matching lines display next set of matching lines display previous set of matching lines edit displayed files in order write the list of lines being displayed to a file append the list of lines being displayed to a file read lines from a file filter all lines through a shell command replacing the lines originally found with the output of the shell command pipe all lines to a shell command displaying the output of the shell command without changing the list of lines found 9 5 Compilation Systems Volume 1 Tools 9 6 If the first character of the text for which you are searching matches one of these commands you can escape the command by entering a backslash before the character Now examine the code around the
73. a window with too few lines it will not simply fail with the vague error message out of storage Instead it will check the window size and generate a more significant error message before exiting Command Line Options 9 10 As noted cscope builds a symbol cross reference table for the C lex and yace source files in the current directory by default cscope is equivalent to cscope chly The following example shows how you can browse through selected source files by invoking escope with the names of those files as arguments cscope filel c file2 c file3 h cscope provides command line options that allow you greater flexibility in specifying source files to be included in the cross reference When you invoke cscope with the s option and any number of directory names separated by commas cscope s dir dir dir cscope will build a cross reference for all the source files in the specified directories as well as the current directory To browse through all of the source files whose names are Browsing Through Your Code with cscope listed in file file names separated by spaces tabs or new lines invoke cscope with the i option and the name of the file containing the list cscope i file If your source files are in a directory tree the following commands will allow you to browse through all of them easily find name chly print sort gt file cscope i file Note that if this option is selected cscop
74. abc produces for example on the standard output Tracking Versions with SCCS 1 3 new delta 1 4 67 lines Undoing a get e There may be times when a file is retrieved accidentally for editing there is really no edit ing that needs to be done at this time In such cases the unget command can be used to cancel the delta reservation that was set up Additional get Options If get r and or t are used together with e the version retrieved for editing is the one specified with r and or t get i and x are used to specify a list of deltas to be included and excluded respec tively see get 1 for the syntax of such a list Including a delta means forcing its changes to be included in the retrieved version This is useful in applying the same changes to more than one version of the SCCS file Excluding a delta means forcing it not to be applied This may be used to undo the effects of a previous delta in the version to be created Whenever deltas are included or excluded get checks for possible interference with other deltas Two deltas can interfere for example when each one changes the same line of the retrieved g file A warning shows the range of lines within the retrieved g file where the problem may exist The user should examine the g file to determine what the problem is and take appropriate corrective steps edit the file if necessary CAUTION get iandget x should be used with extreme care get k is used
75. an object file Specifically the internal rule is C 0 S GET S GFLAGS lt S CC S CFLAGS c c rm f Thus appended to any suffix transforms the file search into an SCCS file name search with the actual suffix named by the dot and all characters up to but not including The following SCCS suffixes are internally defined Cw sh Mo yr h Ye 1 ES L S The following rules involving SCCS transformations are internally defined Ors SS A Le sr a CC Cr Vas 2S 01 2C vas Po E o Shes AQ yu sh sh AE yw hash Y 0 yr y Ez IN Ger AE Tex L C AO foras L 0 heeds Ee L L ors Obviously the user can define other rules and suffixes that may prove useful The provides a handle on the SCCS file name format so that this is possible There are many programs that consist of a single source file make handles this case by the null suffix rule Thus to maintain the UNIX system program cat a rule in the makefile of the following form is needed Cy CC S CFLAGS o 80 lt S LDFLAGS 13 13 Compilation Systems Volume 1 Tools Included Files SCCS Makefiles In fact this c rule is internally defined so no makefile is necessary at all The user only needs to enter make cat dd echo date these are all UNIX system single file programs and all four C language source files are passed through the above shell command line associated with the c rule The internally
76. and have no length limit 1d calculates the addresses and length of the current segment based on the previous segment s attribute values Also even though implicitly declared segments default to no length limit any machine memory limitations still apply LOAD segments can have an explicitly specified virtual address value and or physical address value as well as a maximum segment length value e Ifa segment has a segment flags value of with nothing following the value defaults to not readable not writable and not executable The alignment value is used in calculating the virtual address of the beginning of the segment This alignment only affects the segment for which it is specified other segments still have the default alignment unless their alignments are also changed If any of the virtual address physical address or length attribute values are not set 1d calculates these values as it builds the a out If an alignment value is not specified for a segment it is set to the built in default The default differs from one CPU to another and may even differ between kernel versions You should check the appropriate documentation for these numbers 4 26 Mapping Directives Link Editor and Linking If both a virtual address and an alignment value are specified for a seg ment the virtual_address value takes priority e Ifa virtual_address value is specified for a segment the alignment field in the progr
77. and weak definitions except for those in the set of names When building an executable Bhide is the default Only those names referenced by the shared objects with which the executable is linked are exported Bhide with a set of symbol names instructs 1d to export all global and weak definitions except those in the specified set Names in a Bhide list that are referenced by the shared objects with which the executable is linked are ignored that is they are exported Bexport means to export all global and weak definitions Bexport with a set of symbol names means to hide all global and weak definitions except those in the set of names and those referenced by the shared objects with which the executable is linked If Bhide and Bexport are used together one of the options must contain a set of symbol names and the other must not In this case the option without the symbol set is ignored Neither Bhide nor Bexport may be used with dn All uninitialized global variables within a module will be assigned contiguous addresses Bsymbolic list filename list is a comma separated sequence of symbol names filename contains a list of symbol names one symbol name per line Lines beginning with a character and blank lines are ignored When building a shared object if a definition for a named symbol exists bind all references to the named symbol to that definition If no list of symbols is provided bind all references t
78. are used to parse error messages from compilers with filename line number listed first on the line Except where explicitly indicated in the individual report all times are reported in terms of cycles Because no analysis of pipe conflicts across basic blocks is done times are always reported in terms of a range of times from max time to min time All sorts are done on max time and percentages are calculated in terms of max time 11 9 Compilation Systems Volume I Tools Usage report is invoked as follows report H a b B number c d range i 7 1 m M megahertz n N number o O number 7r R number s t T file w Y character z Z character programfile programfile prof The programfile argument specifies the name of the executable file over which analyze has patched for producing profile information All other arguments are optional and are as follows H Print a help message and exit a Report on all the individual data sets recorded in the profile data file If the t option is used normally only the totals for all the runs of the program are printed The a option forces all the individual runs to generate reports as well b Generate a report showing where the program spent its time at the individual basic block level This report is ordered with the most expensive block listed first in terms of cycles spent in that block B number Restrict the basic
79. checks for error conditions local to C source files in the second for inconsistencies across them This process is invisible to the user unless lint is invoked with c lint c filel c file2 c That command directs lint to execute the first pass only and collect information relevant to the second about inconsistencies in definition and use across filel c and file2 c in intermediate files named filel lnand file2 ln ls 1 filel c filel in file2 c file2 1n In this way the c option to Lint is analogous to the c option to ec which suppresses the link editing phase of compilation Generally speaking lint s command line syntax closely follows cc s When the 1n files are linted lint filel ln file2 1n the second pass is executed lint processes any number of c or 1n files in their command line order So lint filel ln file2 1n file3 c directs Lint to check file3 c for errors internal to it and all three files for consistency lint searches directories for included header files in the same order as cc NOTE For further information see Preprocessing Directives in Con current C Reference Manual lint Libraries Analyzing Your Code with lint Use the I option to lint as you would the I option to cc If you want lint to check an included header file that is stored in a directory other than your current directory or the standard place specify the path of the directory with I as follows lint Idir
80. cmpi cmpl cmpli 3 5 Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC D Reo Mime Syntax of Operands Description POWER Mnemonic entlzd rA rS Count Leading Zeros Doubleword entlzw rA rS Count Leading Zeros Word entlz crand BT BA BB Conditional Register AND E crandc BT BA BB Conditional Register AND with Complement 5 crclr BT Conditional Register Clear Bit Same as crxor BT BT BT creqv BT BA BB Conditional Register Equivalent crmove BT BA Conditional Register Move Same as cror BT BA BA crnand BT BA BB Conditional Register NOT AND crnor BT BA BB Conditional Register NOT OR crnot BT BA Conditional Register NOT Same as crnor BT BA BA cror BT BA BB Conditional Register OR crorc BT BA BB Conditional Register OR with Complement crset BT Conditional Register Set Bit Same as creqv BT BT BT crxor BT BA BB Conditional Register Exclusive OR dcbf rA rB Data Cache Block Flush debi rA B Data Cache Block Invalidate Supervisor Level dcbst rA rB Data Cache Block Store debt rA rB Data Cache Block Touch debtst rA rB Data Cache Block Touch for Store dcbz rA rB Data Cache Block set to Zero delz div o T rA rB Divide 601 only divd o T rA rB Divide Doubleword divdu o T rA rB Divide Doubleword Unsigned divs o T rA rB Divide Short 601 only divw o T rA rB Divide Word divwulo T rA rB Divide Word Unsigned doz o FLA IB Difference or Zero 601 only
81. create a yace parser with the command yacc grammar y where grammar y is the file containing your yacc specification The y suffix is a convention recognized by other UNIX system commands It is not strictly necessary The output is a file of C language subroutines called y tab c The function produced by yacc is called yyparse and is integer valued When it is called it in turn repeatedly calls yylex the lexical analyzer supplied by the user see Lexical Analysis on page 7 7 to obtain input tokens Eventually an error is detected yyparse returns the Parsing with yacc value 1 and no error recovery is possible or the lexical analyzer returns the end marker token and the parser accepts In this case yyparse returns the value 0 You must provide a certain amount of environment for this parser in order to obtain a working program For example as with every C language program a routine called main must be defined that eventually calls yyparse In addition a routine called yyerror is needed to print a message when a syntax error is detected These two routines must be supplied in one form or another by the user To ease the initial effort of using yacc a library has been provided with default versions of main and yyerror The library Liby is accessed by a ly argument to the cc command The source codes main return yyparse and include lt stdio h gt yyerror s char s
82. creating creating 4 12 4 13 4 18 short directive 2 14 Signal functions 16 47 Signal Handling Functions 16 47 size directive 2 18 size 1 1 5 Sizer 1 5 Sorter topological 1 5 Special files functions 16 12 Special purpose register name 2 6 Stack 1 6 Stack frame 1 6 Statement null 2 4 Static link 1 6 static linking 4 8 implementation 4 17 STATIC_LINK environment variable 4 8 Straightening blocks 20 10 20 11 STREAMS functions 16 11 Strength reduction 20 13 20 18 20 20 20 21 String and characters functions 16 22 string directive 2 16 String Manipulation Functions 16 22 String manipulation functions 16 23 strip 1 1 5 Stripper 1 5 Subprograms inline expansion 20 26 Symbol table 1 5 2 1 Table symbol 1 6 Symbolic debugger 1 3 1 4 Symbols 2 2 2 6 System environment functions 16 53 System libraries 16 1 Table symbol 1 5 2 1 Table functions 16 31 Table Management 16 31 tdesc 1 6 tdesc text description 23 1 Temporary file functions 16 22 TERM environment variable 9 2 Terminal I O functions 16 10 Test replacement 20 18 20 21 Text description tdesc 23 1 Text description information 1 6 text directive 2 13 text segment see also object files 4 17 4 18 4 19 4 20 4 21 Time Functions 16 33 TMPDIR environment variable 2 2 9 13 Topological sorter 1 5 Translator 1 5 Tree functions 16 31 Trigonometric Functions 16 37 Trigonometric functions 16 37 Trigonometric identities 20 17 tsort 1 1 5
83. defined single suffix rules are eC sh op a NER sh Mo 255 SER Mer 3882 sh Others may be added in the makefile by the user The make program has a capability similar to the include directive of the C preprocessor If the string include appears as the first seven letters of a line ina makefile and is followed by a blank or a tab the rest of the line is assumed to be a file name which the current invocation of make will read Macros may be used in file names The file descriptors are stacked for reading include files so that no more than 16 levels of nested includes are supported Makefiles under SCCS control are accessible to make That is if make is typed and only a file named s makefile or s Makefile exists make will do a get on the file then read and remove the file Dynamic Dependency Parameters 13 14 A dynamic dependency parameter has meaning only on the dependency line in a makefile The refers to the current thing to the left of the symbol which is 8 Also the form GF exists which allows access to the file part of Thus in the following cat SS c the dependency is translated at execution time to the string cat c This is useful for building a large number of executable files each of which has only one source file For instance the UNIX system software command directory could have a makefile like CMDS cat dd echo date cmp comm chown Managing File Interactions with make C
84. delta branching off trunk delta 1 3 will be 1 3 1 1 As other deltas on that same branch are created only the sequence number changes 1 3 1 2 1 3 1 3 etc This is shown in Figure 14 2 ORORO RORO Figure 14 2 Tree Structure with Branch Deltas The branch number is incremented only when a delta is created that starts a new branch off an existing branch as shown in Figure 14 3 As this secondary branch develops the sequence numbers of its deltas are incremented 1 3 2 1 1 3 2 2 etc but the secondary branch number remains the same Tracking Versions with SCCS E ep OOOO Figure 14 3 Extended Branching Concept The concept of branching may be extended to any delta in the tree and the numbering of the resulting deltas proceeds as shown above SCCS allows the generation of complex tree structures Although this capability has been provided for certain specialized uses the SCCS tree should be kept as simple as possible Comprehension of its structure becomes difficult as the tree becomes complex SCCS Command Conventions SCCS commands accept two types of arguments key letters and file names Key letters are options that begin with a hyphen followed by a lowercase letter and in some cases a value File and or directory names specify the file s the command is to process Naming a directory is equivalent to naming all the SCCS files within the directory Non SCCS files and unreadable files in the named di
85. exist with the given attributes and sectiontype If the same section is specified by more than one section directive the last value of attributes and sectiontype is assigned to the section Any combination of the following flags can be specified in the attributes string w Set the SHF_WRITE flag 0x1 x Set the SHF_ALLOC flag 0x2 a Set the SHF_EXECINSTR flag 0x4 The assembler permits one of the following flags to be specified as sectiontype The assembler requires that the given value be preceded with an progbits The section may contain data nobits The section contains no data symtab The section is a symbol table strtab The section is a string table note The section is a comment section vendor The section is a Concurrent Computer Corporation vendor section A hexadecimal integer constant may also be specified as sectiontype provided it is preceded by or as described above Some of the flags do not have meaning in a PowerMAX OS environment They are provided for compatibility with other systems As an example 2 13 Compilation Systems Volume 1 Tools section mysect a progbits specify mysect as SHF_ALLOC and SHT_PROGBITS previous Data Initialization This directive exchanges the current section and the previous section At any point in the assembly both a current section and a previous section are in effect Initially the current section is text and the previous section
86. externals are not known at assembly time A manifest value is also an absolute value All absolute values are also manifest values except for the difference between two relocatable values The following rules determine the type of an expression based upon the types of the operands If both operands are of manifest type the expression is manifest If both operands are of absolute type the expression is absolute If one operand is an undefined external the expression is an undefined external If one operand is absolute and the other operand is relocatable the expression is relocatable The difference of two relocatable operands is of absolute type tis not possible for one operand to be manifest while the other is absolute or relocatable Expression Values An absolute symbol is defined from a constant and its value is not affected by the link editor Text data and bss symbols have values which indicate their displacements from the beginning of the text data or bss sections respectively Text data and bss sym bols may change in value if the assembler output is link edited At the beginning of assembly the value of the location counter is the beginning displacement of the text section After the first data directive is seen the value of becomes the beginning displacement of the data section 2 11 Compilation Systems Volume 1 Tools Symbols which are declared global have global visibili
87. files For large databases you will be able to find a symbol in a few seconds instead of the several minutes it can take to build without q at the expense of about twice as much database disk space and build CPU time Updating a q database takes about half as long as building it It contains binary numbers so it is portable only between machines with the same byte ordering The q option makes it practical to have databases for entire projects If you try to build a project database and get a ile too large message you need to get your login s ulimit raised by your system administrator See sh 1 for information on the shell built in ulimit command If you get the no space left on device message you will have to use a file system with more space You can change the temporary file system by setting the TMPDIR environment variable If you have enough space to build the data base but not to rebuild it after some files have changed try removing the inverted index cscope in out and cscope po out files If you still don t have enough space to rebuild remove the cscope out file Check the escope 1 page for other command line options Using Viewpaths cscope searches for source files in the current directory by default When the environment variable VPATH is set cscope searches for source files in directories that comprise your viewpath A viewpath is an ordered list of directories each of which has the same directory structure below i
88. for Use after Initial Search o ooo oooooomoooo o 9 5 Table 9 3 Commands for Selecting Lines to Be Changed 9 15 Table 14 1 Determination of New SID 0 00 00 14 14 Table 16 1 File and I O Control and Access Functions 16 5 Table 16 2 File and I O Status Functions 0 0 0 0 eee eee eee 16 6 Table 16 3 Directories Functions 16 7 Table 16 4 File Systems Functions 0 0 00 cece eee eee 16 7 Table 16 5 General Input Functions 0 0 ee 16 8 Table 16 6 General Output Functions 22 0 0 0 0 eee eee 16 9 Table 16 7 Terminal I O Functions 0 0 0 eee eh 16 10 Table 16 8 STREAMS Functions 0 0 00 16 11 Table 16 9 Pipes and FIFOs Functions 00 0 0 eee eee eee 16 12 Table 16 10 Devices Control Functions 0 00 0 eee eee 16 12 Table 16 11 File Systems Table File Functions 0 00004 16 13 Table 16 12 File Systems Mount Table File Functions 16 14 Table 16 13 Password File Functions 0 0 0 eene 16 14 Table 16 14 Shadow Password File Functions 00 000 0008 16 15 Table 16 15 Group File Functions 0 0 cee eee eee 16 15 Table 16 16 User and Accounting Information Files 0 16 16 Table 16 17 ELF Files Functions 0 0 0 0 eee ee eee 16 17 Table 16 18 DWARF Debugging Information
89. form expression action where the action may be continued on succeeding lines by using braces to delimit it The lex operator characters are Xe UD eee ox ES A Seok eer Important lex variables functions and macros are Lexical Analysis with lex yytext array of char yyleng int yylex function yywrap function yymore function yyless n function REJECT macro ECHO macro input macro unput c macro output c macro 6 19 Compilation Systems Volume I Tools 6 20 7 Parsing with yacc Introduction Ies MA hea o Beat 7 1 Basic Specifications eee di id dkny ah Sal E 7 3 ACHONS er ee en en Ren Den se tb NU ee 7 5 I exical AnalySisz Asse A nr 7 7 Parser Operation un ns ah ra rs 7 9 Ambiguity and Conflicts 0 00 0 2 ec e 7 12 Precedence nee done A SE A es 7 16 Error Handling ee er eet eec testa Nee ne 7 20 The yacc Environment 0 ccc eee ere 7 22 Hints for Preparing Specifications llle 7 23 Input Style sede veert cer DR EDGE tae RM RUD PED ERR Ris 7 24 Left RECULSION ueste chee Re Cede ii 7 24 Lexical Tie In cios een ER ee oes 7 25 Reserved Words ede ee pr RR pet REDIERE 7 26 Advanced TOPICS cce A De E CR Ee e ees 7 26 Simulating error and accept in Actions 00 0 0 cee eee eee eee 7 26 Accessing Values in Enclosing Rules 0 0 0 0 eee ee eee 7 26 Support for Arbitrary Value Types 2 0 00 c eee eee eee 7 27 yacc In
90. g k or a Note that the characters between brackets must be adjacent without spaces or punctuation The operator when it appears as the first character after the left bracket indicates all characters in the standard set except those specified between the brackets Note that and may serve other Lexical Analysis with lex purposes as well see below Ranges within a standard alphabetic or numeric order A through Z a through z 0 through 9 are specified with a hyphen a z for instance indicates any lowercase letter Somewhat more interestingly A Za z0 9 amp 4 is a regular expression that matches any letter whether upper or lowercase any digit an asterisk an ampersand or a sharp character Given the input text 5552 2 S amp r r 4 the lexical analyzer with the previous specification in one of its rules will recognize amp r and perform on each recognition whatever action the rule specifies we have not indicated an action here and print out the rest of the text as it stands If you want to include the hyphen character in the class it should appear as the first or last character in the brackets A Z or A Z The operators become especially powerful in combination For example the regular expression to recognize an identifier in many programming languages is a zA Z 0 9a zA Z An identifier in these languages is defined to be a letter followed by zero or more
91. h In the example above the first line states that prog depends on three o files Once these object files are current the second line describes how to combine them to create prog The third line states that x o and y o depend on the file defs h From the file system make discov ers that there are three c files corresponding to the needed o files and uses built in rules on how to generate an object from a C source file that is issue acc c command If make did not have the ability to determine automatically what needs to be done the following longer description file would be necessary proq X O0 yziO Z40 CC BO YO Z 0 lm o prog x o X C defs h CO FE XC y o y c defs h Ce REN MIC Z O i Zo CG HG SZGC Managing File Interactions with make If none of the source or object files have changed since the last time prog was made and all of the files are current the command make announces this fact and stops If however the defs h file has been edited x c and y c but not z c are recompiled and then prog is created from the new x oand y o files and the existing z o file If only the file y c had changed only it is recompiled but it is still necessary to relink prog If no target name is given on the make command line the first target mentioned in the description is created otherwise the specified targets are made The command make x o would regenerate x o if x c or defs h had changed A method ofte
92. had been written SACT empty 1 A f Bo 4SACT G x 2 y 3 7 where SACT is an empty action In many applications output is not done directly by the actions A data structure such as a parse tree is constructed in memory and transformations are applied to it before output is generated Parse trees are particularly easy to construct given routines to build and maintain the tree structure desired For example suppose there is a C function node written so that the call node L nl n2 creates a node with label L and descendants n1 and n2 and returns the index of the newly created node Then a parse tree can be built by supplying actions such as expr expr expr node EN 1 3 Parsing with yacc in the specification You may define other variables to be used by the actions Declarations and definitions can appear in the declarations section enclosed in and These declarations and definitions have global scope so they are known to the action statements and can be made known to the lexical analyzer For example oe S int variable 0 could be placed in the declarations section making variable accessible to all of the actions You should avoid names beginning with yy because the yacc parser uses only such names Note too that in the examples shown thus far all the values are integers A discussion of values of other types is found in Advanced Topics on page 7 26
93. input seen expr expr matches the right side of the grammar rule above The parser could reduce the input by applying this rule After applying the rule the input is reduced to expr the left side of the rule The parser would then read the final part of the input expr and again reduce The effect of this is to take the left associative interpretation Alternatively if the parser sees expr expr 1t could defer the immediate application of the rule and continue reading the input until xpr xpr xpr is seen It could then apply the rule to the rightmost three symbols reducing them to expr which results in expr expr being left Now the rule can be reduced once more The effect is to take the right associative interpretation Thus having read expr expr the parser can do one of two valid things shift or reduce It has no way of deciding between them This is called a shift reduce conflict It may also happen that the parser has a choice of two valid reductions This is called a reduce reduce conflict Note that there are never any shift shift conflicts When there are shift reduce or reduce reduce conflicts yace still produces a parser It does this by selecting one of the valid steps wherever it has a choice A rule describing the choice to make in a given situation is called a disambiguating rule yacc invokes two default disambiguating rules 1 Ina shift reduce conflict the default is to do the shift
94. keyword St ype is used to associate union member names with non terminals Thus one might say Stype lt nodetype gt expr stat to associate the union member nodet ype with the non terminal symbols expr and stat There remain a couple of cases where these mechanisms are insufficient If there is an action within a rule the value returned by this action has no a priori type Similarly reference to left context values such as 0 leaves yace with no easy way of knowing the type In this case a type can be imposed on the reference by inserting a union member name between lt and gt immediately after the first The example below Stma alto Sho bbb tun lt imteva lo 2 9 lt other gt 00 shows this usage This syntax has little to recommend it but the situation arises rarely A sample specification is given in Example 2 below The facilities in this subsection are not triggered until they are used In particular the use of St ype will turn on these mechanisms When they are used there is a fairly strict level of checking For example use of Sn or to refer to something with no defined type is diagnosed If these facilities are not triggered the yacc value stack is used to hold ints yacc Input Syntax Parsing with yacc This section has a description of the yacc input syntax as a yacc specification Context dependencies and so forth are not considered Ironically although yace accepts an LALR 1 grammar the
95. letters or digits and that is just what the regular expression says The first pair of brackets matches any letter The second if it were not followed by a would match any digit or letter The two pairs of brackets with their enclosed characters would then match any letter followed by a digit or a letter But with the the example matches any letter followed by any number of letters or digits In particular it would recognize the following as identifiers e not idenTIFIER pH EngineNo99 R2D2 Note that it would not recognize the following as identifiers not idenTIFIER 5times Shello because not_idenTIFIER has an embedded underscore 5times starts with a digit not a letter and hello starts with a special character A potential problem with operator characters is how we can specify them as characters to look for in a search pattern The last example for instance will not recognize text with a in it lex solves the problem in one of two ways an operator character preceded by a backslash or characters except backslash enclosed in double quotation marks are taken literally that is as part of the text to be searched for To use the backslash method to recognize say a followed by any number of digits we can use the pattern xe t 9 6 5 Compilation Systems Volume I Tools Actions 6 6 To recognize a itself we need two backslashes NN Similarly x x matches x x and y z ma
96. llle 10 35 too many arguments for format 0 00 0 2 eee eee eee 10 36 value type declared inconsistently 0 00 0c eee ee eee eee 10 36 value type used inconsistently 2 2 0 eee eee eee 10 37 variable may be used before set name 0 00 eee 10 37 variable unused in function 0 0 eee cee eee 10 37 Chapter 11 Performance Analysis TIrtroduction A aes Shes A ele RP d 11 1 analyze ues aie tees etae E edite tese Suse Dai O te tila ts 11 1 IO ON voe eU re UN EUR Eos CIERRE uiui 11 1 Statistics Sere abet rera ML a c bee 11 3 Profiling en ea UTER USE ORAE aod 11 3 xi Compilation Systems Volume 1 Tools sage X sn ns ae al ne Mise eld 11 4 Assumptions and Constraints leslie 11 9 TEPOL an ERU A CRM ER e NE eda E E RN 11 9 WS ABS i c ee e e de ces re t Rr ERU 11 10 Assumptions and Constraints 0 0 ee eee 11 12 Part 3 Project Control Chapter 12 Introduction to Project Control Introduction s ved y OV DC UR EU ple be gata we ERR Pins 12 1 Chapter 13 Managing File Interactions with make Introductiomn or voor Lee ARAN EE DEANE GAO Ee ale 13 1 Basic Beat res se osos eR deno e ERA e HE 13 2 Parallel Mike 0 EAR CER eRe A S CAE RENE 13 5 Description Files and Substitutions 0 00 cece eee eee eee 13 6 Comments vd duce A A AP ERUN EG 13 6 Continuation Lines 13 6 Macro DESTINOS AA ie LG AND CRUCEROS SIUE NAN 13 6 General Form u ee
97. n arguments invoking lint with v suppresses it for every argument int fun int x int y return x ARGSUSED1 int fun2 int x int y return X OmMDANA UO BWN EF argument unused in function 1 y in fun array subscript cannot be gt value value Format Simple The value of an array element s subscript exceeded the upper array bound 1 int fun 2 3 int a 10 4 int p a 5 while p amp a 10 using address is ok 6 ptt 7 return a 5 6 8 7 warning array subscript cannot be 9 11 array subscript cannot be negative value Format Simple The constant expression that represents the subscript of a true array as opposed to a pointer had a negative value 10 13 Compilation Systems Volume 1 Tools 1 int f 2 3 int a 10 4 return a 5 2 10 2 5 4 warning array subscript cannot be negative 1 assignment causes implicit narrowing conversion Format Compound An object was assigned to one of a smaller type Invoking lint with a suppresses the message So does an explicit cast to the smaller type 1 void fun 2 3 short s 4 long 1 0 5 s l 6 assignment causes implicit narrowing conversion 5 assignment of negative constant to unsigned type Format Simple A negative constant was assigned to a variable of unsigned type Use a cast or the U suffix 1 void fun 2 3 unsigned i 4 i 1 5
98. never used 222er 10 28 Compilation Systems Volume 1 Tools name multiply defined 0 0 eee eee 10 28 name used but not defined 0 0 cee ee eee 10 28 nonportable bit field type eee eee ee 10 29 nonportable character constant 0 0 0 cee cee eee ee 10 29 only 0 or 2 parameters allowed main 0 000 c eee eee eee 10 29 pointer cast may result in improper alignment 04 10 30 pointer casts may be troublesome 0 0 eee 10 30 precedence confusion possible parenthesize arrr 10 31 precision lost in bit field assignment 0 0 0 0 0c e ee eee 10 31 set but not used in function 0 0 0 eee eee cee eee 10 32 statement has no consequent else 62 eee eee 10 32 statement has no consequent if 0 0 eee eee 10 32 statement has null effect 0 2 ee nen 10 33 statement not reached 0 0 ee teens 10 33 static n sed A E egt D Rd PR 10 34 suspicious comparison of char with value op op2 llle esses 10 34 suspicious comparison of unsigned with value op op 10 35 too few arguments forformat lesse 10 35 too many arguments for format 00 0 0 cece eh 10 36 value type declared inconsistently 0 00 cece eee ee eee 10 36 value type used inconsistently n o 0 eee eee eee 10 37 variable may be used before set name 0 00 0 ee
99. newly found line Enter 1 the number of the line in the list The editor will be invoked with the file alloc c the cursor will be at the begin ning of line 63 of alloc c return alloctest realloc p unsigned size check for memory allocation failure statie chan alloctest p char Sp fee oy EN UT void fprintf stderr n s out of storage n argv0 exit 1 return p MR ST NS ASS ies Screen 9 4 Examining a Line of Code Found by cscope You can see that the error message is generated when the variable p is NULL To determine how an argument passed to alloctest could have been NULL you must first identify the functions that call alloctest Exit the editor by using normal quit conventions You are returned to the menu of tasks Now type alloctest after the fourth item Find functions calling this function Browsing Through Your Code with cscope Text string out of storage File Line Je adlocscwe63 void skprinur stderr Nissi Oros ystobLage n sano 0 5 Find this C symbol Find this global definition Find functions called by this function Find functions calling this function alloctest Find this text string Change this text string Find this egrep pattern Find this file Find files including this file Screen 9 5 Requesting a List of Functions That Call alloctest cscope finds and lists three such functions Functions calling this function a
100. no longer continue parsing according to the specification The input tokens it has seen together with the lookahead token cannot be followed by anything that would result in a valid input The parser reports an error and attempts to recover the situation and resume parsing The error recovery as opposed to the detection of error will be discussed later Consider token DING DONG DELL o oe oe rhyme sound place 7 sound DING DONG i place DELL Parsing with yacc as a yace specification When yacc is invoked with the v verbose option a file called y output is produced with a human readable description of the parser The y output file corresponding to the above grammar with some statistics stripped off the end follows Saccept _rhyme Send DINA shitt 3 error rhyme goto 1 sound goto 2 Saccept rhyme_ end Send accept GLEQ rhyme H Sound place DELS Shites error place goto 4 sound H DING DONG DONG shift 6 CECEO rhyme sound place_ 1 reduce 1 place DELL_ 3 reduce 3 sound DING DONG_ 2 reduce 2 The actions for each state are specified and there is a description of the parsing rules being processed in each state The _ character is used to indicate what has been seen and what is yet to come in each rule The following input DING DONG DELL can be used to track the operations of the parser Initially the current state is state 0 The parser needs to refer
101. of a library 1ibx so in preference to the archive library implementation libx a in the same directory By default the link editor searches for libraries in the standard places on your system usr 1ib and lib in that order In this arrangement then C programs are dynamically linked with libc so automatically cc filel c file2 c file3 c To link your program statically with libc a turn off the dynamic linking default with the Zlink static option 4 35 Compilation Systems Volume 1 Tools 4 36 cc Zlink static filel c file2 c file3 c Specify the 1 option explicitly to link your program with any other library If the library is in the standard place the command cc filel c file2 c file3 c lx will direct the link editor to search for Libx so then 1ibx a in the standard place Note that the compilation system supplies shared object versions only of 1ibc and libdl Other shared object libraries are supplied with the operating system and usually are kept in the standard places Note too that as a rule it s best to place 1 at the end of the command line If the library is not in the standard place specify the path of the directory in which it is stored with the L option cc L dir filel c file2 c file3 c 1x or the environment variable LD_LIBRARY_PATH LD LIBRARY PATH dir export LD LIBRARY PATH cc filel c file2 c file3 c 1x If the library is a shared object and is not in the standard place you mu
102. of an object file s symbol table This utility adds deletes prints or compresses a section by default the comment section in an ELF object file This utility is used to provide a readable display of all components of an object file This utility gives the byte size of selected sections of an object file This utility is used to remove the symbol table from an object file This utility available on some UNIX systems for compression of COFF symbolic debug information in an object file has been adapted by Concurrent Computer Corporation to compress DWARF symbolic debug information from ELF files This utility provides a readable display of the machine level instructions in an object file This utility is unique to Concurrent Computer Corporation For a particular program counter value within an object file it utilizes DWARF symbolic debug information to present the file name and line number which correspond to that address This utility serves as a macro processor front end for source files written in C and other languages This utility finds the ordering relation of object files for a library This utility builds a graph of external function references from C yacc lex assembler and object files This utility provides an ordered list of items which are usually the output from lorder 1 Object Files An object file is a binary container of machine instructions and reference information Relocatable object fil
103. on 601 543 DBAT3L Data Block Address Translation 4 Lower not on 601 771 PMCI RD Performance Monitor Counter 1 Read Only 620 only 772 PMC2 RD Performance Monitor Counter 2 Read Only 620 only 779 MMCRO RD Mask Register Read Only 620 only 936 UMMCRO User Mask Register 0 750 only 937 UPMCI Performance Monitor Counter 1 750 only 938 UPMC2 Performance Monitor Counter 2 750 only 939 USIA Sampled Instruction Address Register 750 only 940 UMMCRI Mask Register 1 750 only 941 UPMC3 Performance Monitor Counter 3 750 only 942 UPMC4 Performance Monitor Counter 4 750 only 952 MMCRO Mask Register 0 604 e 620 750 only 953 PMCI Performance Monitor Counter 1 604 e 620 750 only 954 PMC2 Performance Monitor Counter 2 604 e 620 750 only 955 SIA Sampled Instruction Address Register 604 e 620 750 only 956 MMCRI Mask Register 1 604e 750 only 957 PMC3 Performance Monitor Counter 3 604e 750 only 958 PMC4 Performance Monitor Counter 4 604e 750 only 959 SDA Sampled Data Address Register 604 e 620 only 976 DMISS Data TLB Miss Address src only 602 603 e only 977 DCMP Data TLB Compare src only 602 603 e only 978 HASHI Primary Hash Address src only 602 603 e only 979 HASH2 Secondary Hash Address src only 602 603 e only 3 29 Compilation Systems Volume 1 Tools Table 3 5 Special Purpose Registers Cont Number Name Description 980 IMISS Instruction TLB Miss Address src only
104. oooo o 9 14 Adding an Argument to a Function 0 0 00 eee 9 17 Changing the Value of a Variable o oooooooocmooooooooo o 9 18 Technical PS o de don 9 18 Unknown Terminal Type 0 0 cee eee eee eee 9 18 Command Line Syntax for Editors 0 0 2 0 eee eee 9 18 Chapter 10 Analyzing Your Code with lint Introduction to lint i iocos ei ea 10 1 Options and Directives o ooooocococoococono ee 10 1 lint and the Compiler ones cete eee e 10 2 Message Formats veia as ER Re yen SERE WM eT SENE SEE ES 10 2 What TintiDoes cete be ta oe ee etie Ro en 10 2 Consistency Checks ode 22 28 2 8 22 Een 10 2 Portability Checks 22 2 ee bU e ee a s 10 3 Suspicious Constructs leere 10 5 Usage es i e ed eee e eee de meo is do dit 10 6 lint Libranes eiue er DA RE CE PU ROME EAE 10 7 lint Filters ce A IR RER evi 10 8 Options and Directives Listed 2 0 0 ee eee eee 10 8 lint specific Messages 0 cee I 10 12 argument unused in function lisse eee 10 13 array subscript cannot be gt value value esee 10 13 array subscript cannot be negative value 00 eee eee 10 13 assignment causes implicit narrowing conversion 005 10 14 assignment of negative constant to unsigned type 005 10 14 assignment operator found where was expected 10 14 bitwise operation on signed value nonportable
105. option saves some space in the output file Produce a pseudo cross reference listing on the standard output Each file and archive library is examined and all external symbols are listed along with the names of the object files which define and or reference the symbols An executable output file is not produced Force a fatal error if any undefined symbols remain at the end of the link This is the default when building an executable It is also useful when building a shared object to assure that the object is self contained that is that all its symbolic references are resolved internally z lowzeroes lowzeros znodefs ztext Bbind_now Support dereferencing of null pointers The link editor creates a segment at addresses 0 inclusive through 0x1000 exclusive consisting entirely of read only zeroes Allow undefined symbols This is the default when building a shared object It may be used when building an executable in dynamic mode and linking with a shared object that has unresolved references in routines not used by that executable This option should be used with caution In dynamic mode only force a fatal error if any relocations against non writable allocatable sections remain In dynamic mode only this option adds a DT_BIND_NOW entry to the dynamic section of the output file This entry instructs the dynamic linker to process all relocations for the object containing this entry before transferring control to t
106. or yace source files it builds a symbol cross reference table for the functions function calls macros variables and preprocessor symbols in those files It then lets you query that table about the locations of symbols you specify First it presents a menu and asks you to choose the type of search you would like to have performed You may for instance want escope to find all functions that call a specified function When cscope has completed this search it prints a list Each list entry contains the name of the file the number of the line and the text of the line in which cscope has found the specified code In this example the list will also include the names of the functions that call the specified function If you choose the latter cscope invokes the editor for the file in which the line appears with the cursor on that line You may now view the code in context and edit the file as you would any other file You can then return to the menu from the editor to request a new search Because of the procedure you follow there is no single set of instructions for using cscope For an extended example of its use review the cscope session described in the next section It shows how you can locate a bug in a program without learning all the code How to Use cscope In the first example an error message out of storage appears intermittently in the program prog just as the program starts up The following series of steps shows you how to u
107. other security 16 52 parameter 16 45 password file 16 14 pipes and FIFOs 16 12 POSIX timer 16 35 processes 16 45 profile 16 44 program 16 44 queues 16 33 random number 16 42 regular expression and pattern matching 16 27 security 16 50 semaphores 16 33 shadow password file 16 15 shared memory 16 30 shared object 16 22 signal 16 47 special files 16 12 STREAMS 16 11 string and characters 16 22 string manipulation 16 23 system environment 16 53 tables 16 31 temporary file 16 22 terminal I O 16 10 trees 16 31 trigonometric 16 37 user and accounting files 16 16 user level interrupt 16 49 wide character test 16 26 wide string manipulation 16 24 G gdb 1 1 4 General input functions 16 8 General output functions 16 9 Index 5 Compilation Systems Volume 1 Tools General register name 2 6 General purpose library 16 3 get 1 14 2 14 4 14 8 14 9 14 17 global directive 2 16 global symbols 4 22 Grapher 1 5 Group file functions 16 15 half directive 2 14 Hash table functions 16 31 Hash Table Management 16 31 header files lint 1 ing 10 6 10 7 help 1 14 5 14 9 14 23 High level language 1 2 Hyperbolic Functions 16 38 Hyperbolic functions 16 38 I O control functions 16 4 ident directive 2 18 2 19 Identifier ordering 1 5 predefined 2 6 user defined 2 6 Identifiers 2 5 ifiles 4 23 Induction variable 20 20 Inline expansion 20 11 20 26 Inline expansion of subprograms 20 10 20 26 Input F
108. precision lost in bit field assignment 8 10 31 Compilation Systems Volume 1 Tools set but not used in function Format Compound An automatic variable or a function parameter was declared and set but not used in a function 1 void fun y 2 int y 3 4 int x 5 x 1 6 y 15 7 set but not used in function 4 x in fun 1 y in fun statement has no consequent else Format Simple An if statement had a null else part Inserting EMPTY between the else and semicolon suppresses the message for that statement invoking lint with h suppresses it for every statement 1 void f a 2 int a 3 4 if a 5 return 6 else 7 6 warning statement has no consequent else statement has no consequent if 10 32 Format Simple An if statement had a null if part Inserting EMPTY between the controlling expression of the if and semicolon suppresses the message for that statement invoking lint with h suppresses it for every statement Analyzing Your Code with lint 1 void f a 2 int a 3 4 f a 5 f a 10 6 EMPTY 7 else return 8 4 warning statement has null effect Format Compound statement has no consequent if An expression did not generate a side effect where a side effect was expected Note that the message is issued for every subsequent sequence point that is reached at which a side effect is not generated
109. returns to its caller after the end marker is seen and accepts the input If the end marker is seen in any other context it is an error It is the job of the user supplied lexical analyzer to return the end marker when appropriate Usually the end marker represents some reasonably obvious I O status such as end of file or end of record Actions Parsing with yacc With each grammar rule you can associate actions to be performed when the rule is recognized Actions may return values and may obtain the values returned by previous actions Moreover the lexical analyzer can return values for tokens if desired An action is an arbitrary C language statement and as such can do input and output call subroutines and alter arrays and variables An action is specified by one or more state ments enclosed in and For example and XXX YYY ZZZ void printf a message n flag 25 are grammar rules with actions The symbol is used to facilitate communication between the actions and the parser The pseudo variable represents the value returned by the complete action For example the action 1 returns the value of one in fact that s all it does To obtain the values returned by previous actions and the lexical analyzer the action can use the pseudo variables 1 2 n These refer to the values returned by components through n of the right side of a rule with the components being numbered from left
110. right and nonassoc need not but may be declared by token as well Precedences and associativities are used by yacc to resolve parsing conflicts They give rise to the following disambiguating rules 1 Precedences and associativities are recorded for those tokens and literals that have them 2 A precedence and associativity is associated with each grammar rule It is the precedence and associativity of the last token or literal in the body of the rule If the prec construction is used it overrides this default Some grammar rules may have no precedence and associativity associated with them 3 When there is a reduce reduce or shift reduce conflict and either the input symbol or the grammar rule has no precedence and associativity then the two default disambiguating rules given in the preceding section are used and the conflicts are reported 4 If there is a shift reduce conflict and both the grammar rule and the input character have precedence and associativity associated with them then the conflict is resolved in favor of the action shift or reduce associated with the higher precedence If precedences are equal then associativity is used Left associative implies reduce right associative implies shift nonassociating implies error Conflicts resolved by precedence are not counted in the number of shift reduce and reduce reduce conflicts reported by yacc This means that mistakes in the specification of precede
111. routine Next analyze performs a local timing analysis for each basic block to determine statistics like the time spent in the block or places where execution is delayed due to pipe constraints etc A companion tool report produces information that is useful in evaluating the program s performance analyze can also be used to transform or even eliminate instructions in the program to produce faster running code Thus it is able to further optimize code that has previously been compiled The lowest level of detailed output is generated with the d option which generates a disassembly listing and the v option which annotates that listing with detailed information on the resources being used Because there is so much information it is compressed into a fairly cryptic form 11 1 Compilation Systems Volume I Tools t This indicates the relative clock time Everything on the same line happens at the same time utr An entry that starts with the letter u indicates a resource is now being used The number following the u is the sequence number of the instruction within the basic block that is using the resource finally the resource name appears immediately following the number resource names are things like registers or pipeline stages fir An entry that starts with indicates the instruction at the given sequence has now freed the resource b r The b entry indicates an instruction that has been blocke
112. rules are not needed Literal characters such as a comma must also be passed through the lexical analyzer and are also considered tokens Specification files are very flexible It is relatively easy to add to the above example the rule date month day year allowing 7 4 1776 as a synonym for July 4 1776 on input In most cases this new rule could be slipped into a working system with minimal effort and little danger of disrupting existing input The input being read may not conform to the specifications With a left to right scan input errors are detected as early as is theoretically possible Thus not only is the chance of reading and computing with bad input data substantially reduced but the bad data usually can be found quickly Error handling provided as part of the input specifications permits the reentry of bad data or the continuation of the input process after skipping over the bad data In some cases yacc fails to produce a parser when given a set of specifications For example the specifications may be self contradictory or they may require a more power ful recognition mechanism than that available to yacc The former cases represent design errors the latter cases often can be corrected by making the lexical analyzer more power ful or by rewriting some of the grammar rules While yace cannot handle all possible specifications its power compares favorably with similar systems Moreover the constructs th
113. s with y and or m causes delta neither to read from the standard input nor to write to the standard output The differences between the g file and the d file constitute the delta and may be printed on the standard output by using delta p The format of this output is similar to that produced by diff The admin Command The admin command is used to administer SCCS files that is to create new SCCS files and change the parameters of existing ones When an SCCS file is created its param eters are initialized by use of key letters with admin or are assigned default values if no key letters are supplied The same key letters are used to change the parameters of exist ing SCCS files Two key letters are used in detecting and correcting corrupted SCCS files see Auditing on page 14 28 Newly created SCCS files are given access permission mode 444 read only for owner group and other and are owned by the effective user Only a user with write permission in the directory containing the SCCS file may use the admin 1 command on that file Creation of SCCS Files An SCCS file can be created by executing the command admin ifirst s abc in which the value first with i is the name of a file from which the text of the initial delta of the SCCS file s abc is to be taken Omission of a value with i means admin is to read the standard input for the text of the initial delta The command admin i s abc first is equivalent t
114. single precision floating point value as an integer Rotate RA by RB bits Do amtfsf Oxff from a memory location pointed to by RA without modifying any floating point registers Set the thread register to a value abs RT RA Generate an functionally equivalent code sequence on implementations without an abs instruction fabs FT RB Generate code to raise to a power Sngle precision version of pow fsqrt FT FB Generate function call for implementations without an fsqrt instruction fsqrts FT FB Generate function call for implementations without an fsqrts instruction 4 Link Editor and Linking Introduction ir eh Beat 4 1 Using the Link Editor oie ee eec ei E 4 1 Basics of linking REIR DERE Ede se ers 4 8 Default Arrangement i ecce repe Ree Ce C eos 4 9 Linking with Standard Libraries llle eese 4 10 Creating and Linking with Archive and Shared Object Libraries 4 11 Specifying Directories to Be Searched by the Link Editor 4 13 Specifying Directories to Be Searched by the Dynamic Linker 4 15 Checking for Run Time Compatibility lees eese 4 16 Dynamic Linking Programming Interface 0 0c eee eee eee 4 17 Implementations ose eo cere Shee As 4 17 Guidelines for Building Shared Objects eese eee eee 4 18 Multiply Defined Symbols 00 0 0c eee cee eee 4 22 Mapfiles tos dt id 4 23 Using the Mapfile Option
115. string 2 Allow multiple file directives in the source program Create a formatted listing on standard output The format of the printout is line number pc memory layout source line The pc field in a data section will be followed by a Mark the object module as using features unique to the PowerPC 601 and provide warnings for any assembly instructions which are unique to another PowerPC chip architecture Mark the object module as using features unique to the PowerPC 603 and provide warnings for any assembly instructions which are unique to another PowerPC chip architecture Mark the object module as using features unique to the PowerPC 604 and provide warnings for any assembly instructions which are unique to another PowerPC chip architecture QTARGET PPC604E Mark the object module as using features unique to the PowerPC QTARGET PPC620 604e and provide warnings for any assembly instructions which are unique to another PowerPC chip architecture Mark the object module as using features unique to the PowerPC 620 and provide warnings for any assembly instructions which are unique to another PowerPC chip architecture QTARGET PPCCOMPAT Y md dir Mark the object module as using only features common to all the PowerPC platforms and provide warnings for any assembly instructions which are unique to any of the platforms If Qy is specified place the version number of the assembler be
116. string per byte The quoted string is regarded as a C style string The leading and the terminating double quotes are not assembled and the string is appended with a trailing null byte 10 For example asciiz error in format n syntax error n Symbol Definitions def def set set identifier expression The assembler requires that expression be of absolute or relocatable type A new symbol identifier is created and its value is set to the value of expression For example def temp 2 4 create a variable temp giving it the value 8 global globl identifier identifier is made externally visible If identifier is defined in this assembly its definition may be used by the link editor to resolve external references to it If identifier is not defined in this assembly the link editor must locate an external definition to satisfy its external reference For example global sub give sub external visibility extern extern identifier identifier is regarded as being defined in another source file For example extern var identify var as defined in another source file 2 16 Assembler and Assembly Language comm comm identifier size alignment identifier is made externally visible and is to be assigned to a common area of size bytes If identifier is not defined at link time the link editor assigns it to the bss section identifier becomes relocatable size is of manifest typ
117. than 1ibfoo a As we saw earlier when the link editor encounters otherwise identically named shared object and archive libraries in the same directory it searches the library with the so suffix by default For the same reason it will search 1ibc so here rather than libc a Note that you must specify L if you want the link editor to search for libraries in your current directory You can use a period to represent the current directory To direct the link editor to search libfoo a you can turn off the dynamic linking default cc Zlink static L home mylibs filel c file2 c file3 c 1foo 4 13 Compilation Systems Volume 1 Tools 4 14 Under Zlink static the link editor will not accept shared objects as input It will search libfoo a rather than libfoo so and libc a rather than libc so To link your program statically with libfoo a and dynamically with libc so you can do either of two things First you can move libfoo a to a different directory home archives for example then specify home archives with the L option cc L home archives L home mylibs filel c file2 c file3 c 1foo As long as the link editor encounters the home archives directory before it encoun ters the home mylibs directory it will search 1ibfoo a rather than libfoo so That is when otherwise identically named so and a libraries exist in your directories the link editor will search the first one it finds The same thing is true by t
118. the lexical analyzer include lt stdio h gt include lt ctype h gt doge egsi2 6 int base Sstart list token DIGIT LETTER colonel Sleft amp cias Yanik ea Sleft o ots Sleft UMINUS supplies precedence for unary minus g1 beginning of rules section empty Trst Stat INM TISE Error en n yyerrok expr Gord prints e Sd n sls LETTER expr Legs od 537 2 expr Plot 97 expr ek sem expr expr 7 31 Compilation Systems Volume I Tools expr amp expr 1 amp 3 expr N ES expr prec UMINUS 2 LETTER reg 1 number DIGIT 1 base number DIGIT base 1 2 7 beginning of subroutines section int yylex lexical analysis routine return LETTER for lowercase letter AFA AA Wrchroughe 23027 JA ret rno DIGIT foridigity sv O through Irs all other characters are returned immediately 2 eH skip blanks while c getchar c is now nonblank if islower c VA Eee E return LETTER IE sde Cc vary e FOG return DIGIT return c 7 32 Parsing with yacc 2 An Advanced Example This section gives an example of a grammar using some of the advanced features The desk calculator in Example 1 is modified to provide a desk calculator that does floating point interval arithmetic The calculator understan
119. the check succeeds the user is informed that other deltas are in progress and processing continues If the check fails an error message results It should be noted that concurrent executions of get must be carried out from different directories Subsequent executions from the same directory will attempt to overwrite the g file which is an SCCS error condition In practice this problem does not arise because each user normally has a different working directory See Protection on page 14 26 fora discussion of how different users are permitted to use SCCS commands on the same files Table 14 1 shows the possible SID components a user can specify with get left most column the version that will then be retrieved by get and the resulting SID for the delta which delta will create right most column In the table R L B and S mean release level branch and sequence numbers in the SID and m means maximum Thus for example R mL means the maximum level number within release R R L mB 1 1 means the first sequence number on the new branch maximum branch number plus 1 of level L within release R Note that if the SID specified is R L R L B or R L B S each of these specified SID numbers must exist The b key letter is effective only if the b flag see admin 1 is present in the file An entry of means irrelevant The first two entries in the left most column apply only if the d default SID flag is not prese
120. the existing mapfile has the same segment_type value as the segment just read in then the segment is added by segment_type value to maintain the following order 1 INTERP 2 LOAD 3 DYNAMIC 4 NOTE 3 If the segment is of segment_type LOAD and you have defined a virtual_address value for this LOADable segment the segment is placed before any LOADable segments without a defined virtual_address value or with a higher virtual_address value but after any segments with a virtual_address value that is lower As each mapping directive in your mapfile is read in the directive is added after any other mapping directives that you already specified for the same segment but before the default mapping directives for that segment Internal Map Structure One of the most important data structures in 1d is the map structure A default map structure corresponding to the model default mapfile mentioned above is used by 1d when the command is executed Then if the mapfile option is used 1d parses the mapfile to augment and or override certain values in the default map structure A typical although somewhat simplified map structure is illustrated in Figure 4 3 The Entrance Criteria boxes correspond to the information in the default mapping directives and the Segment Attribute Descriptors boxes correspond to the information in the default segment declarations The Output Section Descriptors boxes give the detailed attr
121. the program Lines in the rules section that begin with white space and that appear before the first rule are copied to the beginning of the function yylex immediately after the first brace You might use this feature to declare local variables for yylex Each rule consists of a specification of the pattern sought and the action s to take on finding it The specification of the pattern must be entered at the beginning of a line The scanner writes input that does not match a pattern directly to the output file So the simplest lexical analyzer program is just the beginning rules delimiter 5 It writes out the entire input to the output with no changes at all 6 3 Compilation Systems Volume I Tools Regular Expressions Operators 6 4 You specify the patterns you are interested in with a notation called a regular expression A regular expression is formed by stringing together characters with or without operators The simplest regular expressions are strings of text characters with no operators at all apple orange pluto These three regular expressions match any occurrences of those character strings in an input text If you want to have the scanner remove every occurrence of orange from the input text you could specify the rule orange Because you specified a null action on the right with the semicolon the scanner does nothing but print out the original input text with every occurrence of this regular expression remo
122. the total number of all digit strings in an input text print the running total of the number of digit strings and print out each one as soon as it is found your lex code might be 1 9 digstrngcount printf Sd digstrngcount printf Ss yytext This specification matches digit strings whether they are preceded by a plus sign or not because the indicates that the preceding plus sign is optional In addition it will catch negative digit strings because that portion following the minus sign will match the specification Advanced lex Usage explains how to distinguish negative from positive integers Advanced lex Usage lex provides a suite of features that let you process input text riddled with quite complicated patterns These include rules that decide what specification is relevant when more than one seems so at first functions that transform one matching pattern into another and the use of definitions and subroutines Before considering these features you may want to affirm your understanding thus far by examining an example that draws together several of the points already covered 6 7 Compilation Systems Volume I Tools printf negative integer printf positive integer printf negative fraction no whole number part rail t t road printf railroad is one word crook print Reres a crook function subprogcount G a zA Z printf may have a G word here s yytext
123. to If you want to make changes to it the e edit option must be used This is done as follows get e s lang get ecauses SCCS to create lang for both reading and writing editing It also places certain information about lang in another new file called p lang which is needed later by the delta command Now if you list the contents of your directory you will see s lang lang and p lang get e prints the same messages as get except that the SID for the first delta you will create also is issued Eal new delta 1 2 5 lines Change lang by adding two more programming languages SNOBOL ADA Recording Changes with delta Next use the delta command as follows delta s lang delta then prompts with comments Your response should be an explanation of why the changes were made For example added more languages delta now reads the file p lang and determines what changes you made to lang It does this by doing its own get to retrieve the original version and applying the diff 1 command to the original version and the edited version Next delta stores the changes in s lang and destroys the no longer needed p lang and lang files When this process is complete delta outputs 1 2 2 inserted 0 deleted 5 unchanged The number 1 2 is the SID of the delta you just created and the next three lines summarize what was done to s lang 14 3 Compilation Systems Volume 1 Tools More on get 14 4 The command
124. to Link Register bcr 1 bctr 1 Branch to Count Register i Same as bcctr 1 20 0 bdnz 1 a BD Branch Decrement Count Non Zero bdn 1 a Same as bc 1 a 16 0 BD bdnzCC l a crfA BD Branch Decrement Count Non Zero on CC bdnCC crfA defaults to crf0 Same as bc 1 a BO BI BD bdnzCClr l crfA Branch Decrement Count Non Zero on CC to LR crfA defaults to crf0 Same as bclr 1 BO BLBD bdnzf 1 a BI BD Branch Decrement Count Non Zero False Same as bc 1 a 0 BLBD bdnzflr 1 BI Branch Decrement Count Non Zero False to LR Same as bclr 1 0 BI bdnzlr 1 Branch Decrement Count Non Zero to LR bdnr 1 Same as bclr 1 16 0 bdnzt 1 a BLBD Branch Decrement Count Non Zero True Same as bc 1 a 8 BLBD bdnztlr 1 BI Branch Decrement Count Non Zero True to LR Same as bclr 1 8 BI bdz 1 a BD Branch Decrement Count Zero 7 Same as bc 1 a 18 0 BD bdzCC l a crfA BD Branch Decrement Count Zero on Condition Code bdzCC crfA defaults to crf0 Same as bc 1 a BO BI BD bdzCClr l crfA Branch Decrement Count Non Zero on CC to LR crfA defaults to crf0 Same as bclr 1 BO BLBD bdzf 1 a BLBD Branch Decrement Count Zero False Same as bc 1 a 2 BI BD bdzflr 1 BI Branch Decrement Count Zero False to LR Same as bclr 1 2 BI 3 3 Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC RS 6000 Syntax of Operands Description POWER Mnemonic Mnemonic bdzlr 1 Branch Decre
125. to describe right associative operators The keyword Parsing with yacc nonassoc is used to describe operators like the operator LT in Fortran that may not associate with themselves That is because A NES Bo lily is invalid in Fortran LT would be described with the keyword nonassoc in yacc As an example of the behavior of these declarations the description might be used to structure the input m obs G9 0g ld vs nek o JEN ig as follows a b c d e g in order to achieve the correct precedence of operators When this mechanism is used unary operators must in general be given a precedence Sometimes a unary operator and a binary operator have the same symbolic representation but different precedences An example is unary and binary minus Unary minus may be given the same strength as multiplication or even higher while binary minus has a lower strength than multiplication The keyword prec changes the precedence level associated with a particular grammar rule prec appears immediately after the body of the grammar rule before the action or closing semicolon and is followed by a token name or literal It causes the precedence of the grammar rule to become that of the following token name or literal For example the rules 7 17 Compilation Systems Volume I Tools ix might be used to give unary minus the same precedence as multiplication A token declared by 1eft
126. to the input in order to decide between the actions available in state 0 so the first token DING is read and becomes the lookahead token The action in state 0 on DING is shift 3 state 3 is pushed onto the stack and the lookahead token is cleared State 3 becomes the current state The next token DONG is read and becomes the lookahead token The action in state 3 on the token DONG is shift 6 state 6 is pushed onto the stack and the lookahead is cleared The stack now contains 0 3 and 6 In state 6 without even consulting the lookahead the parser reduces by 7 11 Compilation Systems Volume 1 Tools sound DING DONG which is rule 2 Two states 6 and 3 are popped off the stack uncovering state 0 Consulting the description of state 0 looking for a goto on sound sound goto 2 is obtained State 2 is pushed onto the stack and becomes the current state In state 2 the next token DELL must be read The action is shift 5 so state 5 is pushed onto the stack which now has 0 2 and 5 on it and the lookahead token is cleared In state 5 the only action is to reduce by rule 3 This has one symbol on the right hand side so one state 5 is popped off and state 2 is uncovered The goto in state 2 on place the left side of rule 3 is state 4 Now the stack contains 0 2 and 4 In state 4 the only action is to reduce by rule 1 There are two symbols on the right so the top two states are popped off uncovering state O aga
127. two instructions are equivalent beq crf2 1 L1 be 12 10 1 L1 3 25 Compilation Systems Volume 1 Tools Trap Operand In the following table means unsigned comparison Table 3 3 Trap Operand TO TO Meaning Operand TO Meaning Operand eq equal 4 ne not equal 24 ge greater than or equal 12 Ige logical greater than or equal 5 gt greater than 8 Ist logical greater than 1 le less than or equal 20 lle logical less than or equal 6 It less than 16 llt logical less than 2 ng not greater than 20 Ing logical not greater than 6 nl not less than 12 Inl logical not less than 3 For example the following two instructions are equivalent tweq r3 r4 tw 4 r3 r4 Operand Abbreviations Table 3 4 Operand Abbreviations Abbre 2k m Description viation BA bit number in CR 0 31 BB bit number in CR 0 31 BD 14 bit branch displacement label BFT FPSCR field number target 0 7 BFA FPSCR field number source 0 7 BI bit number in CR 0 31 BO conditional branch options 0 31 BT bit number in CR or FPSCR target 0 31 crfT condition register field target crf0 crf7 crfA condition register field source crf0 crf7 D 16 bit offset 32768 32767 3 26 PowerPC Instruction Set Summary Table 3 4 Operand Abbreviations Cont un Description FLM mask of FPSCR fields 1 255 fA floating point register f0 f31 fB floating point register f0 f31 fC floating point
128. type directive 2 18 type information 22 61 U uahalf directive 2 15 uaword directive 2 15 ubyte directive 2 14 uhalf directive 2 15 undefined symbols 4 8 unget 1 14 8 14 13 Unreachable code 20 11 Unsafe optimizations 20 21 User and accounting file functions 16 16 User defined identifier 2 6 User level interrupt functions 16 49 V val 1 14 9 14 26 Variable EDITOR 9 2 9 18 LD BIND NOW 4 16 22 47 22 55 LD LIBRARY PATH 4 7 4 14 4 36 22 52 LD RUN PATH 4 7 4 15 4 36 MAKEFLAGS 13 18 PARALLEL 13 5 13 17 STATIC LINK 4 8 TERM 9 2 TMPDIR 9 13 VIEWER 9 2 VPATH 9 2 9 13 Variable length displacements 2 20 Variable optimizations 20 10 20 12 20 14 20 15 20 16 Variables Index Copy 20 15 20 16 Number to optimize 20 13 Optimizing 20 12 Separate lifetimes 20 15 vbyte directive 2 14 version directive 2 4 2 6 2 7 2 18 Version number assembler 2 3 VIEWER environment variable 9 2 virtual addressing 22 42 VPATH environment variable 9 2 9 13 w weak directive 2 17 weak symbols 4 22 4 23 what 1 14 9 14 24 14 25 Wide character test functions 16 26 Wide string manipulation functions 16 24 word directive 2 15 Y yacc 1 1 4 7 1 7 39 yacc 1 definitions 7 7 7 8 yacc 1 disambiguating rules 7 12 7 20 yacc 1 error handling 7 20 7 22 yacc 1 how to write source 7 3 7 7 yacc 1 library 6 17 7 22 7 23 yacc 1 parser actions 7 9 7 12 yacc 1 routines 7 26 yacc 1 source format 7
129. unrolling 20 23 20 24 About optimizing variables 20 13 About uninitialized variables 20 35 About zero trip tests 20 11 at unknown line 20 19 Miscellaneous Functions 16 10 16 12 16 27 16 38 16 44 16 45 16 51 16 52 16 53 Mnemonic instruction 2 1 2 6 Mount table file functions 16 14 Multibyte and wide character functions 16 27 multiply defined symbols 4 22 4 23 Name lister 1 5 NightTrace 1 1 4 NightView 1 1 4 nm 1 1 5 Null statement 2 4 Numeric conversion functions 16 39 Numeric Conversions 16 39 O O option 20 2 Object shared 1 6 Object debugger 1 4 Object file 1 5 relocatable 1 3 2 1 2 2 Object File Library 16 2 16 17 16 18 16 35 16 36 Object files 80 bit precision 22 21 22 22 FP rounding modes 22 19 object files 22 1 data representation 22 2 function addresses 22 57 global offset table 22 54 procedure linkage table 22 58 program header 22 35 program interpreter 22 45 program linking 22 3 program loading 22 42 section alignment 22 12 section attributes 22 14 Index 8 section header 22 9 segment contents 22 40 segment permissions 22 39 tools for manipulating 22 1 object files base address base address 22 38 object files ELF header ELF header 22 3 Object files FP exceptions FP exceptions 22 19 object files hash table hash table 22 59 object files libelf libelf 22 1 object files note section note section 22 41 object files relocation relocation 22 27 22 54 object files secti
130. unsigned x if x lt 0 will always fail Whereas the test unsigned x if x gt 0 is equivalent to if x 0 which may not be the intended action lint flags suspicious comparisons of unsigned variables with negative constants or 0 To compare an unsigned variable to the bit pattern of a negative number cast it to unsigned if u unsigned 1 Or use the U suffix if u 1U lint flags expressions without side effects that are used in a context where side effects are expected where the expression may not represent what the programmer intended It issues an additional warning whenever the equality operator is found where the assignment operator was expected in other words where a side effect was expected int fun int a b x y a x amp amp b y lint cautions you to parenthesize expressions that mix both the logical and bitwise operators specifically amp where misunderstanding of operator precedence may lead to incorrect results Because the precedence of bitwise amp for example falls below logical the expression If ux cac 70 10 5 Compilation Systems Volume 1 Tools Usage 10 6 will be evaluated as if x amp a 0 which is most likely not what you intended Invoking lint with h disables the diagnostic You invoke lint with a command of the form lint file c file c lint examines code in two passes In the first it
131. use a shared library function the entire contents of the library are mapped into the virtual address space of your process at run time External references to the function are assigned virtual addresses when you execute the program The link editor records in your executable only the name of the shared object and a small amount of bookkeeping information for use by the dynamic linker at run time We ll take a closer look at how dynamic linking is implemented in a moment First let s consider the one or two cases in which you might not want to use it Earlier we said that because shared object code is not copied into your executable object file at link time a dynamically linked executable normally will use less disk space than a statically linked executable If your program calls only a few small library functions however the book keeping information to be used by the dynamic linker may take up more space in your executable than the code for those functions You can use the size 1 command to determine the difference In a similar way using a shared object may occasionally add to the memory requirements of a process Although a shared object s text is shared by all processes that use it its data typically are not at least its writable data see the subsection Guidelines for Building Shared Objects on page 4 18 for the distinction Every process that uses a shared object usually gets a private copy of its entire data segment regardless
132. void fprintf stderr s n s show the triviality of these default programs The argument to yyerror is a string containing an error message usually the string syntax error The average application wants to do better than this Ordinarily the program should keep track of the input line number and print it along with the message when a syntax error is detected The external integer variable yychar contains the lookahead token number at the time the error was detected This may be of some interest in giving better diagnostics Since the main routine is probably supplied by the user to read arguments for instance the yace library is useful only in small projects or in the earliest stages of larger ones The external integer variable yydebug is normally set to 0 If it is set to a nonzero value the parser will output a verbose description of its actions including a discussion of the input symbols read and what the parser actions are It is possible to set this variable by using gdb 1 Hints for Preparing Specifications This part contains miscellaneous hints on preparing efficient easy to change and clear specifications The individual subsections are more or less independent 7 23 Compilation Systems Volume I Tools Input Style It is difficult to provide rules with substantial actions and still have a readable specifica tion file The following are a few style hints 1 Use all uppercase letters for token names a
133. ways Try to use automatic stack variables Don t use permanent storage if automatic variables will work Use functional interfaces rather than global variables Generally speaking that will make library interfaces and code easier to maintain Moreover defining functional interfaces often eliminates global variables entirely which in turn eliminates global copy data The ANSI C function strerror 3C illustrates these points In previous implementations system error messages were made available to applications only through two global variables extern int sys nerr extern char sys errlist That is sys_errlist X gives a character string for the error X if X is a non negative value less than sys nerr Now if the current list of messages were made available to applications only through a lookup table in an archive library applications that used the table obviously would not be able to access new messages as they were added to the system unless they were relinked with the library In other words errors might occur for which these applications could not produce meaningful diagnostics Something similar happens when you use a global lookup table in a shared library First the compilation system sets aside memory for the table in the address space of each executable that uses it even though it does not know yet where the table will be loaded After the table is loaded the dynamic linker copies it into the space that ha
134. you then change the define statement in the parser rather than hunt through the entire program changing every occurrence of the particular integer In using yacc to generate your parser insert the statement finclude y tab h in the definitions section of your lex source The file y tab h which is created when yacc is invoked with the d option provides define statements that associate token names such as BEGIN END and so on with the integers of significance to the generated parser To indicate the reserved words in the example the returned integer values suffice For the other token types the integer value of the token type is stored in the programmer defined variable tokval This variable whose definition was an example in the definitions section is globally defined so that the parser as well as the lexical analyzer can access it yacc provides the variable yylval for the same purpose Note that the example shows two ways to assign a value to tokval First a function put_in_tabl places the name and type of the identifier or constant in a symbol table so that the compiler can refer to it in this or a later stage of the compilation process More 6 16 Lexical Analysis with lex to the present point put in tabl assigns a type value to tokval so that the parser can use the information immediately to determine the syntactic correctness of the input text The function put_in_tabl would be a routine that the com
135. 0 This order eliminates all warnings Mapfile Option Defaults 4 30 The 1d command has three built in segments text data and note with default segment attribute values and corresponding default mapping directives as described under Segment Declarations on page 4 25 Even though the 1d command does not use an actual mapfile to store the defaults the model of a default mapfile helps to illustrate what happens when the 1d command encounters your mapfile Figure 4 2 shows how a mapfile would appear for the 1d command defaults The 1d command begins execution behaving as if the mapfile in Figure 4 2 has already been read in Then 1d reads your mapfile and either augments or makes changes to the defaults NOTE The interp segment which precedes all others and the dynamic segment which follows the data segment are not shown in Figure 4 2 and Figure 4 3 because you cannot manipu late them text LOAD RX text PROGBITS A W data LOAD RW data PROGBITS AW data NOBITS AW note NOTE note NOTE Figure 4 2 Default Mapfile As each segment declaration in your mapfile is read in it is compared to the existing list of segment declarations as follows Link Editor and Linking 1 If the segment does not already exist in the mapfile but another with the same segment_type value exists the segment is added before all of the existing segments of the same segment_type 2 If none of the segments in
136. 0 Classes of Optimizations llle e 20 10 Branch Optimizations lleeeeeeeeee een nern eren 20 10 Straightening Blocks lt sorei a i E EO eee 20 11 Folding Conditional Tests 20 11 Eliminating Unreachable Code 00 0 cece eee eee 20 11 Inserting Zero Trip Tests 20 11 Duplicating Partially Constant Conditional Branches 20 12 Variable Optimizations 0 0 cee eee cee ee 20 12 Dead Code Elimination 0 0 cece eects 20 13 Copy Propagation lel 22H D RA ee ee 20 14 Separate Lifetimes u ee edam DG era ae tes 20 15 Copy Variables areas 20 15 Expression Optimizations 0 0 0 0 0 sser rererere ereere 20 16 Algebraic Simplification 0 0 00 eee eee 20 16 Address Mode Determination 0 0 0 eee 20 17 Common Subexpression Elimination 0000000084 20 17 Code Motion eod e eee nd este aes oe I e ea 20 17 Loop Optimizations sseeeeeeeee I 20 18 Loops with Multiple Entry Points eese 20 19 Strength Reduction 0 0 0 ee eee eee 20 20 Test Replacement seeker e ea ba gd eck el 20 21 Contents Duplicating Loop Exit Tests 0 0 cee eee eee ee 20 21 Loop Unrolling and Software Pipelining 20 22 Register Allocation 0 0 0 cece eee Ih 20 24 Instruction Scheduling esr ld aa 20 24 Post Linker Optimization 0 0 0 0 cece e 20 25 Inline Expansion o
137. 0 0 2 cee ee e 14 13 Concurrent Edits of Different SID annuns unarna reee 14 13 Concurrent Edits of Same SID 0 ene 14 15 Key letters that Affect Output 00 0000 eee eee eee 14 16 The delta Command A eR ATO REUS 14 17 The admin Command 0 0 ee eee nee eens 14 19 Creatiomof SCCS FUES une ee een ea 14 19 Inserting Commentary for the Initial Delta 2 2220 14 20 Initialization and Modification of SCCS File Parameters 14 20 The PIS Command e ete eret nece De ee Een 14 21 The sact Commands AAA GA S ACE T SACER RARE Ged ae 14 23 The help Command tus eR Ree ade 14 23 The rmdel Command o oo o oo 14 23 The cdc Command 0 ce een en 14 24 The what Command aa 14 24 The sccsdiff Command 0 0 00 ce teen nets 14 25 The comb Command 0 0 ccc cee eee 14 25 The val Command ean a een teen eee ens 14 26 SCGS Hilda 14 26 Protection oc oo aid dats dida hd Badd opt ts 14 26 Formatting ar a ne ERU MUR EAT MIS RN 14 27 AdE i ede me be eue nan teme ea Seta ea a aes 14 28 Compilation Systems Volume 1 Tools Introduction Basic Usage Terminology 14 Tracking Versions with SCCS The Source Code Control System SCCS is a set of programs that you can use to track evolving versions of files ordinary text files as well as source files SCCS takes custody of a file and when changes are made identifies and stores them in the file with the orig
138. 2 45 standard place 4 11 libraries lint 1 10 7 10 8 libraries maintaining 13 11 13 12 Library 1 3 alternate math 16 2 C 16 1 16 2 DWARF Access Library 22 61 ELF 16 3 general purpose 16 3 math 16 2 shared 1 6 system 16 1 Link dynamic 1 6 static 1 6 link editing 22 23 22 45 library linking options 4 9 4 16 4 35 multiply defined symbols 4 22 4 23 quick reference 4 35 undefined symbols 4 8 link editing dynamic dynamic 4 8 22 27 22 45 link editing static static 4 8 Link editor 1 3 1 4 Linking 4 1 lint 1 1 5 10 1 10 38 lint 1 command line 10 6 10 8 lint 1 consistency checks 10 2 10 3 lint 1 filters 10 8 lint 1 libraries 10 7 10 8 lint 1 message formats 10 2 lint 1 messages 10 12 10 38 lint 1 options and directives 10 1 10 2 10 8 10 12 lint 1 portability checks 10 3 10 5 lint 1 suspicious constructs 10 5 10 6 Lister name 1 5 Loadable kernel module functions 16 53 local directive 2 17 Locale functions 16 36 Locale Information 16 36 Location counter 2 5 Loop optimizations 20 10 20 18 20 19 20 20 20 21 20 22 Loop unrolling 20 18 20 22 Loops Forward branch into 20 19 Optimizing 20 17 20 18 20 19 20 20 20 21 20 22 Test replacement 20 21 Unrolling 20 22 With multiple entries 20 19 20 20 lorder 1 1 5 Low level language 1 2 LWP functions 16 49 Index m4 1 1 5 2 2 2 3 5 1 5 10 m4 1 argument handling 5 5 5 7 m4 1 arithmetic capabilities 5 7 m4 1 command line 5 1 5 2 m4 1
139. 20 Appendixl libdwar h sseeleleseeeee eh 25 22 Figure 4 1 User Defined Mapfile ooooooooccoococoror e 4 29 Figure 4 2 Default Mapfile ssr seie ee E E e 4 30 Figure 4 3 Simple Map Structure 0 0 00 0 cece eee eee 4 32 Figure 6 1 Creation and Use of a Lexical Analyzer with lex 6 3 Figure 13 1 Summary of Default Transformation Path 13 10 Figure 14 1 Evolution of an SCCS File 0 0 0 0 eee eee 14 5 Figure 14 2 Tree Structure with Branch Deltas ooo ooocoommmo o o 14 6 Figure 14 3 Extended Branching Concept 00 0000 e eee eee 14 7 Figure 22 1 Data Encoding ELFDATA2LSB 00 0 0 0 00005 22 8 Figure 22 2 Data Encoding ELFDATA2MSB 00 00 0008 22 8 Figure 22 3 Relocatable Fields 0 0 00 0 cee eee eee 22 29 Figure 23 1 The Parts of a Body of Code 0 0 0 0 eee eee 23 1 Screen 9 1 The cscope Menu of Tasks 0 00 00 cee cece eee eee 9 3 Screen 9 2 Requesting a Search for a Text String 0 0 0000 9 4 Screen 9 3 cscope Lists Lines Containing the Text String 9 5 Screen 9 4 Examining a Line of Code Found by cscope 9 6 Screen 9 5 Requesting a List of Functions That Call alloctest 9 7 Screen 9 6 cscope Lists Functions That Call alloctest o 9 7 Screen 9 7 cscope Lists Functions That Call mymall
140. 24 35 Typedef Entries ee a be nah ORAGE 24 36 Array Type Entries een ates ied Sheets 24 36 Structure Union and Class Type Entries else 24 37 General Structure Description eee 24 38 Derived Classes and Structures 0 00 0 0 ccc eee eee eee ee 24 38 Friends a ee eso e eee eh Lese dese 24 39 Structure Data Member Entries 0 000 000 eee ee eee 24 39 Structure Member Function Entries o oooococcoooooooooooo 24 41 Class Template Instantiations 0 00 e eee eee eee ee 24 41 Variant Entries re actin tada cada deh athe a 24 42 Enumeration Type Entries 00 0 0 0 ee eee 24 43 Subroutine Type Entries 2 0 0 ee eee eee 24 44 String Type Entties s lt rele RR ee HER 24 44 A A ER te es e hit oca tg 24 45 Subrange Type Entries osese sone nea A eh 24 45 Pointer to Member Type Entries eene 24 46 Fil Type Entries 2 a eh are 24 47 Other Debugging Information eee eee 24 47 Accelerated ACCES Skio ioie A IRR RR EAT RA Rare 24 47 Lookup by Name s eee 12er a eau ee s E a eas 24 48 Lookup by Address llle 24 48 Line Number Information 0 0 cece cece ene 24 49 Definitions eR Ia ERR tw ROS ee eu EATER PE NN Re 24 49 State Machine Registers nin i 24 50 Statement Program Instructions llesleeeee ee eee ee 24 51 The Statement Program Prologue o o oococcoococcncocor 24 51 The Statement Program 24 53 Special Opcodes us ke OR tee tus 24 53
141. 3 yacc 1 symbols 7 3 7 7 yacc 1 typing 7 27 7 28 yacc 1 usage examples 7 29 7 39 yacc 1 use with lex 1 6 12 6 15 6 17 7 1 7 3 7 7 7 8 7 22 7 23 yacc 1 yylexQ 7 22 yacc 1 yyparse 7 22 7 23 zero directive 2 12 Zero trip test 20 11 Index 11 Compilation Systems Volume 1 Tools Index 12 Spine for 1 5 Binder Product Name 0 5 from top of spine Helvetica 36 pt Bold Volume Number if any Helvetica 24 pt Bold Volume Name if any Helvetica 18 pt Bold Manual Title s Helvetica 10 pt Bold centered vertically within space above bar double space between each title Bar 1 x 1 8 beginning 1 4 in from either side Part Number Helvetica 6 pt centered 1 8 up y O 2 gt gt Oo o Programmer Compilaton Systems Volume 1 Tools 0890459
142. 4 By default these routines are provided as macro definitions To handle special I O needs such as writing to several files you may use standard I O routines in C to rewrite the functions Note however that they must be modified consistently In particular the char acter set used must be consistent in all routines and a value of 0 returned by input must mean end of file The relationship between input and unput c must be maintained or the lex lookahead will not work If you do provide your own input output c or unput c you will have to write a undef input and so on in your definitions section first undef input undef output define input o etc more declarations Lexical Analysis with lex Your new routines will replace the standard ones See Definitions on page 6 12 for fur ther details A lex library routine that you may sometimes want to redefine is yywrap which is called whenever the scanner reaches end of file If yywrap returns 1 the scanner con tinues with normal wrapup on end of input Occasionally however you may want to arrange for more input to arrive from a new source In that case redefine yywrap to return 0 whenever further processing is required The default yywrap always returns 1 Note that it is not possible to write a normal rule that recognizes end of file the only access to that condition is through yywrap Unless a private version of input is supplied
143. 4 3 General Description 1 0 0 o ee cece eens 24 4 The Debugging Information Entry 0 0 0 c eee eee eee 24 4 Attribute Types iii ta eh ees 24 5 Relationship of Debugging Information EntrieS o ooooomooomooo 24 7 Location Descriptions 0 0 cece m mh 24 7 Location Expressions sss 24 8 Register Name Operators sisse 24 8 Addressing Operations 0 0 0 eects 24 8 Literal Encodings 0 0 0 0 nee 24 9 Register Based Addressing eee ee eee 24 10 Stack Op rations ii Bus 24 10 Arithmetic and Logical Operations 000 0005 24 11 Control Flow Operations 0 0 0 0 eee ee eee 24 13 Special Operations ssi we be en 24 13 Sample Stack Operati0NS o ooooooococooorcco nennen 24 13 Example Location Expressions 0 00 cece eee o 24 14 Lee Cation Lasts e M RR P Pees RIS 24 15 Types of Declarations c cious eka nee MERE NUR 24 16 Accessibility of Declarations lleeeleee eA 24 16 Visibility of Declarations 0 0 0 0 cee eee eee 24 16 Virtuality of Declarations nussen eeuu cette ene ae 24 17 Artificial EDESA HON PENG ERS 24 17 Target Specific Addressing Information eee esee 24 17 Non Defining Declarations llle 24 18 Declaration Coordinates 0 0 0 cece ern neren 24 19 Identifier Names us has un RIS WEE SR a eRe EMEN 24 19 Program Scope Entries 2 0 0 ec e 24 19 Compilation Unit Entries
144. 5 Predefined identifer 2 6 Preprocessor C 1 4 previous directive 2 14 Process functions 16 45 Processor language 1 2 prof 1 1 4 Profile functions 16 44 Profiler 1 4 Profiling 1 3 Program executable 1 3 Program counter 1 5 2 5 Program functions 16 44 Program interpreter 1 6 Program Monitoring 16 44 Program optimization 20 1 20 2 Programming language 1 1 Ada 1 2 assembly 1 2 C 1 2 Proramming language Fortran 1 2 prs 1 14 9 14 21 14 22 Pseudo op 2 1 Index Pseudo random number functions 16 42 Pseudo random Number Generation 16 42 Q Q option 20 3 20 8 20 18 benchmark 20 8 block_limit 20 8 fast_math 20 8 growth_limit 20 11 20 20 20 22 loops 20 15 objects 20 13 opt_class 20 2 optimize_for_space 20 8 variable limit 20 8 Qalign double see Table 2 1 20 3 Qavoid overflow see Table 2 1 20 3 Qinline divide see Table 2 1 20 3 Qinvert divides see Table 2 1 20 3 Qnotic see Table 2 1 20 3 Qschedule tn window see Table 2 1 20 3 Qskew large arrays see Table 2 1 20 3 Qtic see Table 2 1 20 3 query operations 22 61 Queue functions 16 33 Queue Management 16 32 16 33 Qunaligned args see Table 2 1 20 3 R Random number functions 16 42 Reference backward 2 5 forward 2 5 Region constant 20 20 Register allocation 20 10 20 24 Register name floating point 2 6 general 2 6 special purpose 2 6 Regular expression and pattern matching functions Index 9 Compilation Systems Volum
145. 6 Table 22 7 Table 22 8 Table 22 9 Table 22 10 Contents Memory Allocation Functions 00 0 0 eee eee eee 16 29 Memory Control Functions ee eee eee ee 16 30 Shared Memory Control Functions 00000 16 30 Tables FUNCION eerte ret el 16 31 Hash Tables Functions 0 0 eee eee eee ee rh 16 31 File Trees Functions endean i ea e 16 32 Binary Trees Functions 0 0 eee eee eee 16 32 Message Queues Functions 16 32 Queues Functions 0 0 ce eee nee nee 16 33 Semaphores Functions 0 0 cee eee eee 16 33 General Date and Time Functions 0 00 e eee eee 16 34 Interval Timer Functions 0 0 e ee eee eee eee 16 35 POSIX Timer Functions 0 000 16 35 Locales Functions d d 0 eee eee eee eens 16 36 Message Catalogs Functions 0 0 eee 16 36 Trigonometric Functions 16 37 Bessel Functions 2 2 0 cece cece eee hh 16 37 Hyperbolic Functions 0 0 eee eee eee 16 38 Miscellaneous Mathematical Functions 00 00 16 38 Numeric Conversion Functions 0 eee cece ee eee eee 16 39 Other Arithmetic Functions 0 0 00 c eee eee eee eee ee 16 41 Floating Point Environment Functions 16 41 Pseudo Random Number Generation Functions 16 42 Flow Functions cec lia edn ok Beep eg ole ue nee 16 44 Profile Functions lees hn 16 44 Parameters F
146. 602 603 e only 981 ICMP Instruction TLB Compare src only 602 603 e only 982 RPA Required Physical Address 602 603 e only 984 TCR Timer Control Register 602 only 986 IBR Interrupt Base Register 602 only 987 ESASRR ESA Save Restore Register 602 only 990 SEBR Special Execute Base Register 602 on ly 99 SER Special Execute Register 602 only 1008 HIDO Hardware Implementation Dependent 0 601 603 e 604 e 620 750 only 1009 HIDI Hardware Implementation Dependent 1 601 602 603e 604e 750 only 1010 IABR Instruction Address Breakpoint Register 601 602 603 e 604 e 620 750 only 1013 DABR Data Address Breakpoint Register 601 604 e 620 750 only 1016 BUSCSR Bus Control 8 Status Register 620 only 1017 L2CR L2 Control Register 620 750 only 1018 L2SR L2 Status Register 620 only 1019 ICTC Instruction Cache Throttling Control Register 750 only 1020 THRMI Thermal 1 750 only 1021 SP Single Precision Tag Register 602 only 1021 THRM2 Thermal 2 750 only 1022 LT Integer Tag Register 602 only 1022 THRM3 Thermal 3 750 only 1022 FPECR Floating Point Exception Cause Register optional not on 601 602 603 e 604 e 1023 PIR Processor ID Register optional not on 602 603 e 750 3 30 Time Base Registers PowerPC Instruction Set Summary Table 3 6 Time Base Registers Number Name Description 268 TBL Time Base not on 601 269 TBU Time Base Upper not on 601 64 bit Implementatio
147. 7 rules oo 06 subroutines when all sections are used The declarations and subroutines sections are optional The smallest valid yace specification might be oe oe un E Blanks tabs and new lines are ignored but they may not appear in names or multi character reserved symbols Comments may appear wherever a name is valid They are enclosed in and as in the C language The rules section is made up of one or more grammar rules A grammar rule has the form A BODY where A represents a non terminal symbol and BODY represents a sequence of zero or more names and literals The colon and the semicolon are yace punctuation Names may be of any length and may be made up of letters periods underscores and digits although a digit may not be the first character of a name Upper case and lower case letters are distinct The names used in the body of a grammar rule may represent tokens or non terminal symbols A literal consists of a character enclosed in single quotes As in the C language the back slash is an escape character within literals yace recognizes all the C language escape 7 3 Compilation Systems Volume I Tools 7 4 sequences For a number of technical reasons the null character should never be used in grammar rules If there are several grammar rules with the same left hand side the vertical bar can be used to avoid rewriting the left hand side In addition the semicolon at the end of a rule
148. A subf o IT rA rB Subtract From subfc o T rA rB Subtract From Carrying sf o subfe o T rA rB Subtract From Extended sfe o subfic rT rA SI Subtract From Immediate Carrying sfi subfme o 1T rA Subtract From Minus One Extended sfme o 3 23 Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC RS 6000 Syntax of Operands Description POWER Mnemonic Mnemonic subfze o 1T rA Subtract From Zero Extended sfze o subi T rA SI Subtract Immediate Same as addi rT rA SI subic T rA SI Subtract Immediate Carrying Same as addic rT rA SI subis 1T rA SI Subtract Immediate Shifted Same as addis rT rA SI sync Synchronize des td TO rA rB Trap Double tdi TO rA SI Trap Double Immediate tdTO rA rB Trap Double If Condition Same as td TO rA rB tdTOi rA SI Trap Double Immediate If Condition Same as tdi TO rA SI tlbia TLB Invalidate All optional not on 601 602 603 e 604 e 620 Supervisor Level tlbie rB TLB Invalidate Entry optional tlbi Supervisor Level tlbiex rB TLB Invalidate Entry by Index optional not on 601 602 603 e 604 e 620 Supervisor Level tlbld rB TLB Load Data Entry 602 603 e only Supervisor Level tlbli rB TLB Load Instruction Entry 602 603 e only Supervisor Level tlbsync TLB Synchronize optional not on 601 Supervisor Level trap Trap Unconditionally Same as tw 31 0 0 tw TO rA rB Trap Word t twi TO rA S
149. AS 1B Shift Right Long With MQ 601 only E sral TAS 1B Shift Right With MQ 601 only 4 3 22 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC El Ro Miente Syntax of Operands Description POWER Mnemonic srw rA rS rB Shift Right Word sr srwil rA rS n Shift Right Word Immediate sri Same as rlwinm rA rS 32 n n 31 stb u IS D rA Store Byte stb u x IS rA rB Store Byte Indexed id std u IS D rA Store Doubleword std u x IS rA rB Store Doubleword Indexed stdex IS rA rB Store Doubleword Conditional Indexed stfd u fS D rA Store Floating Point Double not on 602 stfd u x fS rA rB Store Floating Point Double Indexed not on 602 n stfiwx fS rA rB Store Floating Point as Integer Word Indexed Optional not on 601 stfs u fS D rA Store Floating Point Single a stfs u x fS rA rB Store Floating Point Single Indexed sth u IS D rA Store Halfword sth u x IS rA rB Store Halfword Indexed sthbrx IS rA rB Store Halfword Byte Reverse Indexed 2 stmw rS D rA Store Multiple Word stm stswi 1S rA NB Store String Word Immediate not on 602 stsi StSWX IS rA rB Store String Word Indexed not on 602 stsx stw u IS D rA Store Word st u stw u x IS rA rB Store Word Indexed st u x stwbrx IS rA rB Store Word Byte Reverse Indexed stbrx StWCX IS rA rB Store Word Conditional Indexed sub o T rA rB Subtract Same as subf rT rB rA subc o IT rA rB Subtract Carrying Same as subfc rT rB r
150. Ada See the HAPSE Reference Manual assembly language See Chapter 2 Assembler and Assembly Language in this manual C Fortran and Ada are often referred to as high level languages The source code for programs written in these languages is fairly portable across computer systems provided by different manufacturers In addition these programs can be accepted and processed by compilers produced by different software vendors The literary world provides an abundance of books and references on these languages Assembly language is often referred to as a low level language This language provides mnemonics and directives which usually map one to one with the instruction set and resources of the computer system All of these languages are supported for the supporting hardware platforms Compilation Systems Concepts A compilation system is a set of language processors commands utilities and libraries which can be used in the development of software programs Compilation systems convert source code into binary programs which can be executed on a computer In addition they provide tools and facilities for debugging and analyzing program behavior and character istics At the heart of a compilation system is the language processor Usually this is the compiler A compiler is a program which accepts as input source code written in a high level language It processes this input and produces a lower level representation of the source code
151. Amelia would do And to replace in a text lengthy medical terms with their equivalent acronyms a rule such as Electroencephalogram printf EEG Lexical Analysis with lex would be called for To count the lines in a text we need to recognize the ends of lines and increment a line counter As we have noted lex uses the standard C escape sequences including n for new line So to count lines we might have n lineno where lineno like other C variables is declared in the definitions section that we discuss later Input is ignored when the C language null statement is specified So the rule t n causes blanks tabs and new lines to be ignored Note that the alternation operator can also be used to indicate that the action for a rule is the action for the next rule The previ ous example could have been written t n with the same result The scanner stores text that matches an expression in a character array called yytext You can print or manipulate the contents of this array as you like In fact lex provides a macro called ECHO that is equivalent to printf s yytext We ll see an example of its use in Start Conditions on page 6 13 Sometimes your action may consist of a long C statement or two or more C statements and you wish to write it on several lines To inform lex that the action is for one rule only simply enclose the C code in braces For example to count
152. Compilation Systems Volume 1 Tools SU concurrent 0890459 050 COMPUTER CORPORATION April 1999 Copyright 1999 by Concurrent Computer Corporation All rights reserved This publication or any part thereof is intended for use with Concurrent Computer Corporation products by Concurrent Computer Corporation personnel customers and end users It may not be reproduced in any form without the written permission of the publisher The information contained in this document is believed to be correct at the time of publication It is subject to change without notice Concurrent Computer Corporation makes no warranties expressed or implied concerning the information contained in this document To report an error or comment on a specific portion of the manual photocopy the page in question and mark the correction or comment on the copy Mail the copy and any additional comments to Concurrent Computer Corpora tion 2101 W Cypress Creek Road Ft Lauderdale FL 33309 1892 Mark the envelope Attention Publications Department This publication may not be reproduced for any other reason in any form without written permission of the publisher This document is based on copyrighted documentation from Novell Inc and is reproduced with permission Acknowledgment This manual contains material contributed by 88open Consortium Ltd In this document the term 601 is used as an abbreviation for the phrase PowerPC 601 RISC microprocessor The t
153. D LIBRARY PATH LD LIBRARY PATH must be a list of colon separated directory names an optional second list is separated from the first by a semicolon LD LIBRARY PATH dir di dir dir export LD_LIBRARY_PATH The directories specified before the semicolon are searched in order before the directo ries specified with L the directories specified after the semicolon are searched in order after the directories specified with L Note that you can use LD LIBRARY PATHin Link Editor and Linking place of L altogether In that case the link editor will search for libraries named with 1 first in the directories specified before the semicolon next in the directories specified after the semicolon and last in the standard places You should use absolute path names when you set this environment variable NOTE As we explain in the next subsection LD_LIBRARY_PATH is also used by the dynamic linker That is if LD_LIBRARY_PATH exists in your environment the dynamic linker will search the directories named in it for shared objects to be linked with your program at execution In using LD_LIBRARY_PATH with the link editor or the dynamic linker then you should keep in mind that any directories you give to one you are also giving to the other Specifying Directories to Be Searched by the Dynamic Linker Earlier we said that when you use the 1 option you must point the dynamic linker to the directories of the shared objects that are to be l
154. E da SERA 16 51 AU SECRET pte 16 51 Levels an ei er I a Se A 16 51 Other Security 5c ese sr Rang eek 16 52 Encryption and Decryption 0 0 0 0 eee eee eee eee 16 52 System Environment ooo 16 53 Loadable Kernel Modules 0 0 000 c cece eee eens 16 53 Other System Environment 0 0 0 ees 16 53 Chapter 17 Floating Point Operations Introd ction eee eee e REN GE Su oe a e eae 17 1 IEEE Arithmetic lel MR RERO ne 17 1 Data Types and Formats 0 0 cece cee mh 17 2 Single Precision u 25 2 0 2 e e IHE REPE RP 17 2 Double Precision s e eR venere oet oes 17 2 Language Mappings 0 00 eee II 17 3 Normalized Numbers 0 0 cece cece eee eens 17 3 Denormalized Numbers o ooocococococooo eee ee 17 3 Maximum and Minimum Representable Floating Point Values 17 4 Special Case Values soc Ree pL REDE ET ER 17 4 NaNs and Infinities 2 Ree e epe Re er 17 5 Rounding Co trol sereno tesa D en REOR UR DR 17 6 Floating Point Exceptions llle cee eee 17 6 Exceptions Status Bits and Control BitS oooooooooooomom ooo 17 7 Exception Handling 0 0 pena eh 17 9 Single Precision Floating Point Operations 0 0 00 eese 17 9 Single Precision Functions 0 0 eee eee ee eee 17 11 Double Extended Precision 0 0 0 0 eee eee eee eae 17 11 FEFE Requirements 11 ida eet eve Pc ERU e m ADAE RR 17 11 Conversion of Floatin
155. Eee A A ELE esee a Mit date oie tal et 5 8 Contents System Command coercere a ee ee 5 8 Conditionals sb sure ak is ee hed bs 5 8 String Manipulation 2 2 eect eee 5 9 DO 8 foes air Sag anne eee 5 10 Chapter 6 Lexical Analysis with lex NS A ate ice eO RU ed SNR adco PO RUE It 6 1 Generating a Lexical Analyzer Program eese 6 1 Writing lex SOUrce oui e eee ee cere UP 6 3 The Fundamentals of lex Rules 0 0 0 cece eee eee 6 3 Regular Expressions oda god a nn ten 6 4 Operators e costes Da ae De SE Oe 6 4 AGUODS 4 A ics aa sich tdeo deese s itte ie sar techy sibel 6 6 Advanced lex Usage sess eh 6 7 Some Special Features 00 eee cee 6 8 lex Routines ads 6 10 Definitions 4 eet esae eee oec eam mtt oe weit wis 6 12 Start Conditions eU Sie QR REGE REA RE ER E 6 13 User Routines eec Cie eta eee 6 14 Using lex with yacc uere ee RE eee 6 15 Miscellaneous e eres best ota netics tad adas nee 6 17 Summary of Source Format l l ne 6 18 Chapter 7 Parsing with yacc Introduction o Sikh Rae nes RU IRI IS EROR AER 7 1 Basic Specifications cole a heiter 7 3 ACHONS 22 fastest pe re temas alee e E REO Ets E Eo E eT Besen 7 5 Lexical Analysis i 22 ar RIDE MURDER MCA ake See 7 7 Parser Opera A a 7 9 Ambiguity and Conflicts 0 0 0c eee tert tenes 7 12 Precedence ees sen A es bond 7 16 Error Hand hoc aaa a a RE Ra tn 7 20 The yacc Environment 0 ccc cee ee c
156. Either warning or fatal appears at the beginning of each error message Error mes sages are not numbered The following conditions produce warnings A physical address or a virtual address value or a length value appears for any segment other than a LOAD segment the directive is ignored A second declaration line exists for the same segment that changes an attribute value s the second declaration overrides the original An attribute value s segment type and or segment flags for text and data segment type for note was changed for one of the built in segments An attribute value s segment type segment flags length and or alignment was changed for a segment created by an implicit declaration The following conditions produce fatal errors Specifying more than one M option on the command line Specifying both the r and the M option on the same command line Amapfile cannot be opened or read A syntax error is found in the mapfile NOTE 1d does not return an error if a file name section name segment name or symbol name does not conform to the rules in Mapfile Structure and Syntax on page 4 24 unless this condi tion produces a syntax error For instance if a name begins with a special character and this name is at the beginning of a directive line 1d returns an error If the name is a section_name appearing within the directive 1d does not return an error 4 34 Link Editor and Linking M
157. Finally note that in the following case oe int i printf oe yace will start copying after and stop copying when it encounters the first the one in printf In contrast it would copy in printf if it encountered it there Lexical Analysis You must supply a lexical analyzer to read the input stream and communicate tokens with values if desired to the parser The lexical analyzer is an integer valued function called yylex The function returns an integer the token number representing the kind of token read If there is a value associated with that token it should be assigned to the external variable yylval The parser and the lexical analyzer must agree on these token numbers in order for communication between them to take place The numbers may be chosen by yacc or the user In either case the define mechanism of C language is used to allow the lexical analyzer to return these numbers symbolically For example suppose that the token name DIGIT has been defined in the declarations section of the yace specification file The relevant portion of the lexical analyzer might look like the screen shown below to return the appropriate token 7 7 Compilation Systems Volume I Tools 7 8 int yylex extern int yylval HOKE Tel c getchar switch c case Ome eases TIe Gase wor VV lived mca uU QU aset ee ob bes The intent is to return a token number of DIGIT and a
158. Find Ghis file Find files including this file To MAXSIZE Screen 9 10 Changing a Text String 9 14 Browsing Through Your Code with cscope cscope displays the lines containing the specified text string and waits for you to select those in which you want the text to be changed Change 100 to MAXSIZE File Line err c 19 p total 100 0 get percentage find ej ale CARO OA oe 4 char s 100 algae ker AG o al E OM SOS Esp reads ediz os O10077 Find this C symbol Find this global definition Find functions called by this function Find functions calling this function Find this text string Change this text string Find this egrep pattern Find this file Find files including this file Select lines to change press the key for help Screen 9 11 cscope Prompts for Lines to Be Changed You know that the constant 100 in lines 2 3 and 4 of the list lines 4 26 and 8 of the listed source files should be changed to MAXSIZE You also know that 100 in err c and 0100 0 in read c lines and 5 of the list should not be changed You select the lines you want changed with the following single key commands Table 9 3 Commands for Selecting Lines to Be Changed 1 9 mark or unmark the line to be changed space bar display next set of lines display next set of lines display previous set of lines a mark or unmark all lines to be changed Ctrl d change the m
159. Functions 16 18 Table 16 19 Shared Objects Functions 00 0 0 16 22 Table 16 20 Temporary Files 0 2 eee cee eee 16 22 Table 16 21 String Manipulation Functions 0 0 0 0 000 0008 16 23 Table 16 22 Wide String Manipulation Functions 004 16 24 Table 16 23 Character Test Functions 00 0 urren renren 16 25 Table 16 24 Wide Character Test Functions 0 00 0 000 0008 16 26 Table 16 25 Character Translation Functions eese 16 26 Table 16 26 Multibyte and Wide Characters Functions 16 27 Table 16 27 Regular Expression and Pattern Matching Functions 16 27 Table 16 28 Memory Manipulation Functions 0 008 16 28 Table 16 29 Table 16 30 Table 16 31 Table 16 32 Table 16 33 Table 16 34 Table 16 35 Table 16 36 Table 16 37 Table 16 38 Table 16 39 Table 16 40 Table 16 41 Table 16 42 Table 16 43 Table 16 44 Table 16 45 Table 16 46 Table 16 47 Table 16 48 Table 16 49 Table 16 50 Table 16 51 Table 16 52 Table 16 53 Table 16 54 Table 16 55 Table 16 56 Table 16 57 Table 16 58 Table 16 59 Table 16 60 Table 16 61 Table 16 62 Table 16 63 Table 16 64 Table 16 65 Table 18 1 Table 18 2 Table 18 3 Table 18 4 Table 18 5 Table 18 6 Table 18 7 Table 22 1 Table 22 2 Table 22 3 Table 22 4 Table 22 5 Table 22
160. Gstringcount The first three rules recognize negative integers positive integers and negative fractions between 0 and 1 The use of the terminating in each specification ensures that one or more digits compose the number in question Each of the next three rules recognizes a specific pattern The specification for railroad matches cases where one or more blanks intervene between the two syllables of the word In the cases of railroad and crook we could have simply printed a synonym rather than the messages stated The rule recognizing a function simply increments a counter The last rule illustrates several points The braces specify an action sequence that extends over several lines e Its action uses the lex array yytext which stores the recognized character string Its specification uses the to indicate that zero or more letters may follow the G Some Special Features 6 8 Besides storing the matched input text in yytext the scanner automatically counts the number of characters in a match and stores it in the variable yyleng You may use this variable to refer to any specific character just placed in the array yytext Remember that C language array indexes start with 0 so to print out the third digit if there is one in a just recognized integer you might enter 1 9 if yyleng gt 2 printf c yytext 2 lex follows a number of high level rules to resolve ambiguities that may arise from th
161. I oe is the ID keyword replaced by the SID of the retrieved version of a file Similarly HS and M are the date and name of the g file respectively Thus executing get on an SCCS file that contains the PL I declaration DCL ID CHAR 100 VAR INIT SM I oo oo ie oo gives for example the following DCL ID CHAR 100 VAR INIT MODNAME 2 3 07 18 85 When no ID keywords are substituted by get the following message is issued No id keywords cm7 This message is normally treated as a warning by get although the presence of the i flag in the SCCS file causes it to be treated as an error For a complete list of the keywords provided see get 1 Retrieval of Different Versions 14 10 The version of an SCCS file that get retrieves by default is the most recently created delta of the highest numbered trunk release However any other version can be retrieved with get r by specifying the version s SID Thus get r1 3 s abc retrieves version 1 3 of s abc and produces for example on the standard output Tracking Versions with SCCS 1x3 64 lines A branch delta may be retrieved similarly get r1 5 2 3 s abc which produces for example on the standard output l5 23 234 lines When a SID is specified and the particular version does not exist in the SCCS file an error message results Omitting the level number as in get r3 s abc causes retrieval of the trunk delta with the highest level
162. I Trap Word Immediate ti twTO rA rB Trap Word If Condition tTO Same as tw TO rA rB twTOi rA SI Trap Word Immediate If Condition tTOi Same as twi TO rA SI 3 24 Table 3 1 PowerPC Instruction Set Cont PowerPC Instruction Set Summary PowerPC RS 6000 Syntax of Operands Description POWER Mnemonic Mnemonic xor rA rS rB XOR xori rA rS UI XOR Immediate xoril xoris rA rS UI XOR Immediate Shifted xoriu Condition Codes A or can be appended to conditional branches to indicate predicted branch taken or predicted branch not taken respectively A lower order bit of BO being zero means the default prediction a one means reverse the default prediction The defaults are forward branches are predicted not taken backwards branches are predicted taken and jumps through link or count register are predicted not taken Table 3 2 Condition Codes CC CC Meaning BO BI CC Meaning BO BI eq equal 8bdnzCC 24 4 CRF ne not equal ObdnzCC 24 4 CRF 10 bdzCC 2 bdzCC 12 bCC 4 bCC gt greater than See eq 1 4 CRF le less than or See ne 1 4 CRF equal ng not greater See ne 1 4 CRF than It less than See eq 0 4 CRF ge greater than or See ne 0 4 CRE equal nl not less than See ne 0 4 CRE so summary See eq 3 4 CRF ns not summary See ne 3 4 CRF overflow overflow un unordered See eq 3 4 CRF nu not unordered See ne 3 4 CRF Z Zero See eq See eq nz not zero See ne See ne For example the following
163. ID must be chosen as the owner of the SCCS files This person will administer the files use the admin command and will be SCCS administrator for the project Because other users do not have the same privileges and permissions as the SCCS administrator they are not able to execute directly those commands that require write permission in the directory containing the SCCS files Therefore a project dependent program is required to provide an interface to the get delta and if desired rmdel and cde commands The interface program must be owned by the SCCS administrator and must have the set user ID on execution bit on see chmod 1 This assures that the effective user ID is the user ID of the SCCS administrator With the privileges of the interface program during command execution the owner of an SCCS file can modify it at will Other users whose login names or group IDs are in the user list for that file but are not the owner are given the necessary permissions only for the duration of the execution of the interface program Thus they may modify SCCS only with delta and possibly rmdel and cdc SCCS files are composed of lines of ASCII text arranged in six parts as follows Checksum a line containing the logical sum of all the characters of the file not including the checksum line itself Delta Table information about each delta such as type SID date and time of creation and commentary User Names list of login names and or gr
164. MDS SS c S CC S CFLAGS o Obviously this is a subset of all the single file programs For multiple file programs a directory is usually allocated and a separate makefile is made For any particular file that has a peculiar compilation procedure a specific entry must be made in the makefile The second useful form of the dependency parameter is GF It represents the file name part of Again it is evaluated at execution time Its usefulness becomes evident when trying to maintain the usr include directory from makefile in the usr src head directory Thus the usr src head makefile would look like INCDIR usr include INCLUDES INCDIR stdio h INCDIR pwd h INCDIR dir h INCDIR a out h INCLUDES F cp Se chmod 0444 Se This would completely maintain the usr include directory whenever one of the above files in usr src head was updated Viewpaths VPATH This implementation of make 1 has been enhanced to support VPATH functionality or the concept of viewpaths VPATH is a macro that allows one to specify a list of directories to search for the files make 1 needs to complete its tasks The viewpath may be specified in one or more of four methods First it may be specified on the command line with the v viewpath option where viewpath is some directory absolute or relative to the current working directory other than the current working directory Second it may be sp
165. Most of lint s messages are simple one line statements printed for each occurrence of the problem they diagnose Errors detected in included files are reported multiple times by the compiler but only once by lint no matter how many times the file is included in other source files Compound messages are issued for inconsistencies across files and in a few cases for problems within them as well A single message describes every occurrence of the problem in the file or files being checked When use of a lint filter requires that a message be printed for each occurrence compound diagnostics can be converted to the simple type by invoking lint with the s option NOTE See Usage on page 10 6 for more information What lint Does lint specific diagnostics are issued for three broad categories of conditions inconsistent use non portable code and suspicious constructs In this section we ll review examples of lint s behavior in each of these areas and suggest possible responses to the issues they raise Consistency Checks 10 2 Inconsistent use of variables arguments and functions is checked within files as well as across them Generally speaking the same checks are performed for prototype uses declarations and parameters as for old style functions If your program does not use function prototypes Lint will check the number and types of parameters in each call to a Analyzing Your Code with lint function more strictly than th
166. O GET get GFLAGS LEX lex LFLAGS LD 1d LDFLAGS MAKE make YACC yacc YF LAGS SPECIAL RULES markfile o markfile A echo static char _sccsid 042 grep A 4 markfile N042 gt markfile c SMC Cemarkiilere rm f markfile c SINGLE SUFFIX RULES CC S CFLAGS o lt S LDFLAGS GET GFLAGS lt CC S CFLAGS o c LDFLAGS rm f c Screen 13 1 make Internal Rules 13 20 Managing File Interactions with make AS S ASFLAGS o 0 lt CC o o LDFLAGS an ZiE Eb Pe GET GFLAGS lt a S ASFLAGS o o s 0 o 0 LDFLAGS ZEM ae so Si ep lt 07 chmod x Sa Alam S GET GFLAGS lt cp sh chmod x EIE NS Sh F77 S FFLAGS o 8 lt LDFLAGS S GET GFLAGS lt F77 S FFLAGS o S LDFLAGS rm f f C C C FLAGS lt LDFLAGS gea S GET GFLAGS lt C C C FLAGS C LDFLAGS rm f C DOUBLE SUFFIX RULES SAO o nS oly eo dors dE SSeS s S GET GFLAGS lt CC CFLAGS c lt AR S ARFLAGS lt F casque SIRS ate eto pS CES TCELAGS LU 9 S C R S ARFLAGS o rm f co a S GET GFLAGS lt C A 13 21 Compilation Systems Volume 1 Tools CC S CFLAGS c lt S GET GFLAGS lt CC CFLAGS c c rm f c S YACC YFLAGS lt mv y tab c e GET GFLAGS l
167. Qfpexcept option in Chapter 3 fp spec exec indicate that floating point instructions are speculatively executed Summary of Directives Mnemonics Table 2 1 summarizes the available directives Table 2 1 Available Directives Mnemonic s Argument s align align alignment org counter zero space number text text data data section identifier attributes sectiontype previous byte byte value value ubyte expression expression sbyte expression expression vbyte vbyte number expression half word value value short short value value uhalf expression expression shalf expression expression uahalf value value word int long value value 2 19 Compilation Systems Volume 1 Tools Example 2 20 Table 2 1 Available Directives Cont Mnemonic s Argument s uaword float float double double string ascii expression expression floatconst floatconst floatconst floatconst string string asciiz string string def set identifier expression def set identifier expression global globl extern extern comm comm bss bss identifier identifier identifier size alignment identifier size alignment local identifier identifier weak identifier identifier type identifier type size identifier size version value file file file ident string
168. Qu is m and the command prs d I r1 4 1 s abc may produce DY DO D W C C DENNEN 0 a nc Substitution of data keywords for all deltas of the SCCS file may be obtained by specifying both e and 1 14 22 Tracking Versions with SCCS The sact Command sact is a special form of the prs command that produces a report about files that are out for edit The command takes only one type of argument a list of file or directory names The report shows the SID of any file in the list that is out for edit the SID of the impending delta the login of the user who executed the get e command and the date and time the get e was executed It is a useful command for an administrator The help Command The help command prints information about messages that may appear on the user s terminal Arguments to help are the code numbers that appear in parentheses at the end of SCCS messages If no argument is given help prompts for one Explanatory information is printed on the standard output If no information is found an error message is printed When more than one argument is used each is processed independently and an error resulting from one will not stop the processing of the others For more information see the help 1 page The rmdel Command The rmdel command allows removal of a delta from an SCCS file Its use should be reserved for deltas in which incorrect global changes were made The delta to be removed must be a l
169. RI Save Restore Register 272 SPRGO Special Purpose Register General 0 273 SPRGI Special Purpose Register General 1 274 SPRG2 Special Purpose Register General 2 275 SPRG3 Special Purpose Register General 3 280 ASR Address Space Register 620 only 282 EAR External Access Register optional not on 602 284 TBL Time Base Lower dest only not on 601 285 TBU Time Base Upper dest only not on 601 64 bit 287 PVR Processor Version Register src only 528 IBATOU Instruction Block Address Translation 0 Upper 529 IBATOL Instruction Block Address Translation 0 Lower 530 IBATIU Instruction Block Address Translation 1 Upper 531 IBATIL Instruction Block Address Translation 1 Lower 532 IBAT2U Instruction Block Address Translation 2 Upper 533 IBAT2L Instruction Block Address Translation 2 Lower PowerPC Instruction Set Summary Table 3 5 Special Purpose Registers Cont Number Name Description 534 IBAT3U Instruction Block Address Translation 3 Upper 535 IBAT3L Instruction Block Address Translation 3 Lower 536 DBATOU Data Block Address Translation 0 Upper not on 601 537 DBATOL Data Block Address Translation 0 Lower not on 601 538 DBATIU Data Block Address Translation 1 Upper not on 601 539 DBATIL Data Block Address Translation 1 Lower not on 601 540 DBAT2U Data Block Address Translation 2 Upper not on 601 541 DBAT2L Data Block Address Translation 2 Lower not on 601 542 DBAT3U Data Block Address Translation 3 Upper not
170. S n b Insert from Left Word Immediate Same as rlwimi rA rS 32 b b b n 1 insrdi rA rS n b Insert from Right Doubleword Immediate Same as rldimi rA rS 64 b n b insrwi rA rS n b Insert from Right Word Immediate Same as rlwimi rA rS 32 b n b b n 1 isync Instruction Synchronize ics la 1T D rA Load Address Same as addi rT rA D lax 1T rA rB Load Address Indexed Same as add rT rA rB lbz u 1T D rA Load Byte and Zero Ibz u x 1T rA rB Load Byte and Zero Indexed i ld u T D rA Load Doubleword 3 8 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC El Ro Miente Syntax of Operands Description POWER Mnemonic ld u x T rA rB Load Doubleword Indexed Idarx T rA rB Load Doubleword And Reserve Indexed Ifd u fT D rA Load Floating Point Double not on 602 Ifd u x fT rA rB Load Floating Point Double Indexed not on 602 E lfs u fT D rA Load Floating Point Single y Ifs u x fT rA rB Load Floating Point Single Indexed j Iha u 1T D rA Load Halfword Algebraic Iha u x 1T rA rB Load Halfword Algebraic Indexed Ihbrx 1T rA rB Load Halfword Byte Reverse Indexed Ihz u 1T D rA Load Halfword and Zero Z Ihz u x 1T rA rB Load Halfword and Zero Indexed 5 li rLSI Load Immediate lil Same as addi rT 0 SI lis rT SI Load Immediate Shifted liu Same as addis rT 0 SI Imw 1T D rA Load Multiple Word Im Iscbx T rA rB Load String And Compare Byte Indexed 601 only s Iswi rT rA NB Lo
171. SDEs Intr duction 23 0 ee be pede Eb bt etg 1 1 Programming Languages 0 0 cece eh e 1 1 Compilation Systems Concepts 0 0 0 0c cece ee eee eee 1 2 Concurrent Computer Corporation Compilation Systems 1 3 ObjectiBiles 3i e Re Re eee ote ade Bes 1 5 Stack FLAMES e EA E eps 1 6 Static and Dynamic Linking 0 0 eee e 1 6 Floating Point Arithmetic ooooooooocorcccro m eee 1 7 Chapter 2 Assembler and Assembly Language Introduction nes sn taa ae 2 1 Assembler Operation so wie hee en TEE PP A 2 1 Using the Assembler Aus Des Hanne ee EMEN S ERE Bes 2 2 Assembler Invocation 0 apena a enhn 2 2 Character Set ns en na RA ERR E DAR dete 2 4 Source Statem nts scs A ER RIO MEER TUNE Ce RUE de 2 4 Null Statement 5 eee eR a 2 4 Alphanumeric Labels 0 0 n eee 2 4 Numeric Local Labels 0 0 000 ccc cc ce es 2 5 COMME SSA ES SIS UE ae Eae te 2 5 Identtfiers e Sheree O EU RU EMERGERE ER 2 5 Predefined Symbol 2s eim a Eb Re RU RI Gere Reni 2 6 User Defined SymbolS ooooocccocococoo eh 2 8 Constants cx sc ub nte de ER ROM C RR DICEN ER a 2 8 Integer Consta nts ecco bh eis cR IER ensure 2 8 Floating Point Constants 00 0 cee eh 2 8 Character Constants 0 2 0 eect eh 2 9 ERPIESSIONS cx ls PS IA oe ae 2 9 Expression Operators 0 0 0 cece need 2 10 Operator Precedente seis ecce ea eb she RR E ERIS err E 2 10 Expression
172. Standard Opcodes 0 0 ee eee nee 24 54 Extended Opcodes oleae ea 24 55 Macro Information nennen er enenrennn 24 56 Macinio Ty pes si ate ema dee etc C en 24 57 Define and Undefine Entries 00 0 0 00008 24 57 Start File Entries soo Le gb p ege epe eben 24 57 xix Compilation Systems Volume 1 Tools End File Entries moi rs en er ERIS Es 24 58 Vendor Extension Entries 0 0 0 0 cee eee eee eee 24 58 Base Source Entries 2 2 2 ee ee eee 24 58 Macinfo Entries for Command Line Options 24 58 General Rules and Restrictions 0 0 0 000 eere 24 58 Call Frame Information 00 0 eee 24 59 Structure of Call Frame Information 0 0 0 een 24 60 Call Frame Instructions 0 0 0 0 re 24 62 Call Frame Instruction Usage 0 00 eee ee eee 24 64 Data Representation lesse e 24 64 Vendor Extensibility llle 24 64 Reserved Error Valles 22 22 23 eR Lx e C 24 65 Executable Objects and Shared Objects llle ee eee 24 65 File Constr nts aorta till pe RE eee Rie ai 24 65 Format of Debugging Information 0 00 00 een 24 65 Compilation Unit Header 00 0 cee eee eee 24 66 Debugging Information Entry 0 0 0 0 24 66 Abbreviation Tables 0 0 0 e 24 67 Attribute Encodings 0 0 0 cee eh 24 67 Variable Length Data o eee en IRURE eR UR 24 71 Location Descript
173. T 9 Move From Data Address Breakpoint Register 601 604 e 620 only Supervisor Level Same as mfspr rT 1013 Move From Data Address Register Supervisor Level Same as mfspr rT 19 Move From Data Block Address Translation Lower n not on 601 Supervisor Level Same as mfspr rT 53742n Move From Data Block Address Translation Upper n not on 601 Supervisor Level Same as mfspr rT 53642n Move From Data TLB Compare 602 603 e only Supervisor Level Same as mfspr rT 977 Move From Decrementer Supervisor Level Same as mfspr rT 22 Move From Data TLB Miss Address 602 603 e only Supervisor Level Same as mfspr 976 Move From Data Storage Interrupt Status Register Supervisor Level Same as mfspr rT 18 3 10 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC Mnemonic Syntax of Operands RS 6000 Description POWER Mnemonic mfear mfesasrr mffpecr mffs mfhashl mfhash2 mfhidO mfhidl mfiabr mfibatl mfibatu mfibr IT IT IT IT IT IT IT IT rT n rT n IT Move From External Access Register optional not on 602 Supervisor Level Same as mfspr rT 282 Move From Enable Supervisor Access Save and Restore Register 602 only Supervisor Level Same as mfspr rT 987 Move From Floating Point Exception Cause Register optional not on 601 602 603 e 604 e Supervisor Level Same as mfspr rT 1022
174. aNs VO 17 12 normalized numbers 17 3 rounding 17 6 single precision 17 2 17 9 17 11 single precision functions 17 11 special case values 17 4 square root 17 12 status bits 17 7 unordered condition 17 12 Floating point register name 2 6 Flow functions 16 44 Flow grapher 1 5 Folding conditional tests 20 10 20 11 Format DWARF 1 5 1 6 ELF 1 5 1 6 2 1 Fortran compiler 1 4 Fortran programming language 1 2 Forward reference 2 5 Frame stack 1 6 Function message queue 16 32 function prototypes lint 1 10 2 function prototypes lint 1 checks for 10 7 Functions access control lists 16 51 arithmetic 16 41 auditing 16 51 bessel 16 37 binary tree 16 32 character test 16 25 character translation 16 26 control 16 46 control levels 16 51 data structures 16 31 devices 16 12 directory 16 7 ELF files 16 17 16 18 encryption 16 52 file 16 7 file and I O status 16 6 file systems tables file 16 13 file tree 16 32 floating point 16 41 flow 16 44 general date and time 16 34 general input 16 8 general output 16 9 group file 16 15 hash table 16 31 hyperbolic 16 38 I O control 16 4 Index internationalization 16 35 interval timer 16 35 loadable kernel modules 16 53 locales 16 36 LWP 16 49 mathematic 16 38 mathematic and numeric 16 36 memory 16 28 memory allocation 16 29 memory control 16 30 memory manipulation 16 28 message catalog 16 36 mount table file 16 14 multibyte and wide characters 16 27 numeric conversion 16 39
175. act sequence of operations needed to generate a new version of the program make keeps track of the commands that create files and the relationship between files Whenever a change is made in any of the files that make up a program the make command creates the finished program by recompiling only those portions directly or indirectly affected by the change The relationships between files and the processes that generate files are specified by the user in a description file The basic operation of make is to Find the target in the description file Ensure that all the files on which the target depends the files needed to generate the target exist and are up to date Re create the target file if any of the generators have been modified more recently than the target The description file that holds the information on inter file dependencies and command sequences is conventionally called makefile Makefile s makefile or s Makefile If this naming convention is followed the simple command make is usually sufficient to regenerate the target regardless of the number of files edited since the last make In most cases the description file is not difficult to write and changes infrequently Even if only a single file has been edited rather than entering all the commands to regenerate the target entering the make command ensures that the regeneration is done in the prescribed way 13 1 Compilation Systems Volume 1 Tools Basic Featur
176. ad String Word Immediate not on 602 lsi Iswx T rA rB Load String Word Indexed not on 602 Isx Iwa rT D rA Load Word Algebraic lwarx 1T rA rB Load Word And Reserved Indexed Iwax T rA rB Load Word Algebraic Indexed lwbrx 1T rA rB Load Word Byte Reverse Indexed Ibrx lwz u 1T D rA Load Word and Zero 1 u lwz u x 1T rA rB Load Word and Zero Indexed l u x maskg TAS 1B Mask Generate 601 only d maskir TAS 1B Mask Insert From Register 601 only 2 mcrf crfT crfA Move Condition Register Field merfs crfT BFA Move to Condition Register Field from FPSCR mcrxr crfT Move to Condition Register Field from XER mfasr T Move From Address Space Register Supervisor Level Same as mfspr rT 280 3 9 Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC Mnemonic Syntax of Operands RS 6000 Description POWER Mnemonic mfbatl mfbatu mfbuscr mfcr mfctr mfdabr mfdar mfdbatl mfdbatu mfdcmp mfdec mfdmiss mfdsisr rT n rT n IT IT IT IT IT rT n IT IT IT IT Move From Block Address Translation Lower n 601 only Supervisor Level Same as mfspr rT 52942n Move From Block Address Translation Upper n 601 only Supervisor Level Same as mfspr rT 528 2n Move From Bus Control amp Status Register 620 only Supervisor Level Same as mfspr rT 1016 Move From Condition Register Move From Count Register Same as mfspr r
177. ags L TAJTEE JW C3 1X Note the following when entering mapping directives You must choose at most one section type from the section types listed above The section types listed above are built in types For more information on section types see Chapter 22 Executable and Linking Format ELF The section flags values are A for allocatable W for writable or X for executable If an individual flag is preceded by an exclamation mark 4 27 Compilation Systems Volume 1 Tools the link editor checks to make sure that the flag is not set No spaces are allowed between the question mark exclamation point s and the individual flags that make up the section_flags value e file name may be any legal file name and can be of the form archive_name component_name e g 1ib libc a printf o A file name may be of the form file_name see next bullet item Note that 1d does not check the syntax of file names e If a file_name is of the form file_name 1d simulates a basename see basename 1 on the file name from the command line and uses that to match against the mapfile file_name In other words the file_name from the mapfile only needs to match the last part of the file name from the command line See Mapping Example on page 4 29 If you use the 1 option on the cc or 1d command line and the library after the 1 option is in the current directory you must precede the library with or th
178. ailed because it was called either with a very large number or a negative number By examining the possible values of FLDLINE and REF LINE you can see that there are scenarios in which the value of mdisprefs is negative for example when you are trying to call mymalloc with a negative number Step 4 Edit the Code On a windowing terminal you may have multiple windows of arbitrary size The error message out of storage might have appeared as a result of running prog That may have been one of the situations in which mymalloc was called with a negative number Now you want to be sure that when the program aborts in this scenario in the future it does so after printing the more significant error message screen too small Edit the function dispinit as follows Compilation Systems Volume 1 Tools initialize display parameters void dispinit calculate the maximum displayed reference lines lastdispline FLDLINE 4 mdisprefs lastdispline REFLINE 1 if mdisprefs lt 0 void fprintf stderr n s screen too small n argv0 Se if mdisprefs gt 9 mdisprefs 9 allocate the displayed line array displine int mymalloc mdisprefs sizeof int L display a page of the references void display Screen 9 9 Using cscope to Fix the Problem You have fixed the problem that you began investigating at the beginning of this section Now if prog is run in
179. am header contains the default alignment value NOTE If a virtual_address value is specified the segment is placed at that virtual address For the PowerUX system kernel this creates a correct result For files that start via exec this method creates an incorrect a out file because the segments do not have correct offsets relative to their page boundaries A mapping directive tells 1d how to map input sections to segments Basically you name the segment that you are mapping to and indicate what the attributes of a section must be in order to map into the named segment The set of section attribute values that a section must have to map into a specific segment is called the entrance criteria for that segment In order to be placed in a specified segment of the a out a section must meet the entrance criteria for a segment exactly A mapping directive has the following syntax segment name section attribute value ifile name For a segment name you specify any number of section attribute values in any order each separated by a space At most one section attribute value is allowed for each section attribute You can also specify that the section must come from a certain o file s via the file name substitutable The section attributes and their valid values are as follows section name any valid section name section type SPROGBITS SSYMTAB SSTRTAB SREL SRELA SNOTE SNOBITS section fl
180. ameters 14 20 Part of an SCCS file is reserved for descriptive text usually a summary of the file s contents and purpose It can be initialized or changed by using admin t When an SCCS file is first being created and t is used it must be followed by the name of a file from which the descriptive text is to be taken For example the command admin ifirst tdesc s abc specifies that the descriptive text is to be taken from file desc When processing an existing SCCS file t specifies that the descriptive text if any currently in the file is to be replaced with the text in the named file Thus admin tdesc s abc specifies that the descriptive text of the SCCS file is to be replaced by the contents of desc Omission of the file name after the t key letter as in admin t s abc Tracking Versions with SCCS causes the removal of the descriptive text from the SCCS file The flags of an SCCS file may be initialized or changed by admin f or deleted by admin d SCCS file flags are used to direct certain actions of the various commands See the admin 1 page for a description of all the flags For example the i flag specifies that a warning message stating that there are no ID keywords contained in the SCCS file should be treated as an error The d default SID flag specifies the default version of the SCCS file to be retrieved by the get command admin f is used to set flags and if desired their values For exa
181. amp 69 8 69 8 6 Figure 14 1 Evolution of an SCCSFile This is the normal sequential development of an SCCS file with each delta dependent on the preceding deltas Such a structure is called the trunk of an SCCS tree There are situations that require branching an SCCS tree That is changes are planned to a given delta that will not be dependent on all previous deltas For example consider a program in production use at version 1 3 and for which development work on release 2 is 14 5 Compilation Systems Volume 1 Tools 14 6 already in progress Release 2 may already have a delta in progress as shown in Figure 14 1 Assume that a production user reports a problem in version 1 3 that cannot wait to be repaired in release 2 The changes necessary to repair the trouble will be applied as a delta to version 1 3 the version in production use This creates a new version that will then be released to the user but will not affect the changes being applied for release 2 that is deltas 1 4 2 1 2 2 etc This new delta is the first node of a new branch of the tree Branch delta names always have four SID components the same release number and level number as the trunk delta plus a branch number and sequence number The format is as follows release level branch sequence The branch number of the first delta branching off any trunk delta is always 1 and its sequence number is also 1 For example the full SID for a
182. an be automatically promoted to an interval if the context demands an interval value This causes a large number of conflicts when the grammar is run through yacc 18 shift reduce and 26 reduce reduce The problem can be seen by looking at the two input lines 2 59 3 55 24 and 294b 3 54 A Notice that the 2 5 is to be used in an interval value expression in the second example but this fact is not known until the comma is read By this time 2 5 is finished and the parser cannot go back and change its mind More generally it might be necessary to look ahead an arbitrary number of tokens to decide whether to convert a scalar to an interval This problem is evaded by having two rules for each binary interval valued operator one when the left operand is a scalar and one when the left operand is an interval In the second case the right operand must be an interval so the conversion will be applied automatically Despite this evasion there are still many cases where the conversion may be applied or not leading to the above conflicts They are resolved by listing the rules that yield scalars first in the specification file in this way the conflict will be resolved in the direction of keeping scalar valued expressions scalar valued until they are forced to become intervals This way of handling multiple types is instructive If there were many kinds of expression types instead of just two the number of rules needed would increase dra
183. an omitted operand Signifies instructions defined as optional in the PowerPC architecture definition Signifies implementations that do not include the optional instruction Signifies instructions that are specific to a particular implementation but are not part of the PowerPC architecture definition Signifies both xxx and xxxe In the RS 6000 POWER Mnemonic column PowerPC Instruction Set Table 3 1 PowerPC Instruction Set Means the RS 6000 POWER mnemonic is spelled the same as the PowerPC mnemonic PowerPC A Reo erste Syntax of Operands Description POWER Mnemonic abs o TLrA Absolute Value 601 only x add o T rA rB Add cax o addc o T rA rB Add Carrying a o adde o T rA rB Add Extended ae o addi 1T rA SI Add Immediate cal addic T rA SI Add Immediate Carrying ai addis T rA SI Add Immediate Shifted cau addme o 1T rA Add to Minus One Extended ame o addze o T rA Add to Zero Extended aze o and rA rS rB AND andc rA rS rB AND with Complement andi rA rS UI AND Immediate andil 3 2 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC RS 6000 i Syntax of Operands Description POWER Mnemonic Mnemonic andis rA rS UI AND Immediate Shifted andiu b 1 a LI Branch be 1 a BO BLBD Branch Conditional bectr 1 BO BI Branch Conditional to Count Register bec 1 bclr 1 BO BI Branch Conditional
184. and SCANFLIKEn in the list of directives in Usage on page 10 6 1 include lt stdio h gt 2 main 3 4 int 1 5 printf Ss i 6 function argument type inconsistent with format printf arg 2 int format char test c 5 function called with variable number of arguments Format Compound A function was called with the wrong number of arguments Preceding a function definition with VARARGSn suppresses the message for calls with n or more arguments defining and declaring a function with the ANSI C notation suppresses it for every argument NOTE See function declared with variable number of arguments on page 10 22 for more information 10 21 Compilation Systems Volume 1 Tools file 1 c 1 int 2 3 4 5 int 6 7 8 10 V 1l int 12 13 14 file 2 c 1 int 2 3 4 5 6 7 fun int x int y return x y z FUNZ int x x x x return X ARARGS1 fun3 int x int y return X main extern int fun return fun 1 2 return fun2 1 2 return fun3 1 2 int z int z fun3 fun2 int x 2 3 4 TS function called with variable number of arguments fun Rl c 2 2 c 4 function declared with variable number of arguments Format Compound The number of parameters in a function prototype declaration or definition differed from their number in another declaration or definition Declaring a
185. and the user list Formatting Tracking Versions with SCCS Files created by the admin command are given access permission mode 444 read only for owner group and other This mode should remain unchanged because it generally prevents modification of SCCS files by non SCCS commands Directories containing SCCS files should be given mode 755 which allows only the owner of the directory to modify it SCCS files should be kept in directories that contain only SCCS files and any temporary files created by SCCS commands This simplifies their protection and auditing The contents of directories should be logical groupings subsystems of the same large project for example SCCS files should have only one link name because commands that modify them do so by creating and modifying a copy of the file When processing is done the contents of the old file are automatically replaced by the contents of the copy whereupon the copy is destroyed If the old file had additional links this would break them Then rather than process such files SCCS commands would produce an error message When only one person uses SCCS the real and effective user IDs are the same and the user ID owns the directories containing SCCS files Therefore SCCS may be used directly without any preliminary preparation When several users with unique user IDs are assigned SCCS responsibilities on large development projects for example one user that is one user
186. and variables declared in those files but defined or used elsewhere used there but defined elsewhere or defined there and used elsewhere Invoke the x option to suppress the former complaint u to suppress the latter two Some non portable code is flagged by lint in its default behavior and a few more cases are diagnosed when lint is invoked with p and or Xc The latter tells Lint to check for constructs that do not conform to the ANSI C standard For the messages issued under p and Xc check Usage on page 10 6 Examples n some C language implementations character variables that are not explicitly declared signed or unsigned are treated as signed quantities with a range typically from 128 to 127 In other implementations they are treated as nonnegative quantities with a range typically from 0 to 255 So the test char Cc c getchar if c EOF where EOF has the value 1 will always fail on machines where character variables take on nonnegative values One of lint s p checks will flag any comparison that implies a plain char may have a negative value Note however that declaring c a signed char in the above example eliminates the diagnostic not the problem That s because getchar must return all possible characters and a distinct EOF value so a char cannot store its value This example which is perhaps the most 10 3 Compilation Systems Volume 1 Tools common one arising fro
187. apters in this part Chapter 16 provides an overview of commonly used system libraries Chapter 17 discusses the IEEE floating point operations used on supporting hard ware platforms Chapter 18 describes interfaces between C and Fortran routines on supporting hard ware platforms Part 5 describes performance analysis concepts Chapter 19 provides an introduction to the other chapters in this part Chapter 20 provides a tutorial on program optimization focusing on the optimizations performed by the Concurrent compilers Part 6 covers formats Syntax Notation Chapter 21 provides an introduction to the other chapters in this part Chapter 22 describes the executable and linking format ELF Chapter 23 discusses text description information tdesc Chapter 24 describes the debugging information format DWARF It is primarily a reprint of the DWARF specification from UNIX International Chapter 25 covers the libdwarf library that provides access to DWARF debugging and line number information It is primarily a reprint of a document from UNIX International The following notation is used throughout this guide italic Books reference cards and items that the user must specify appear in italic type Special terms and comments in code may also appear in italic list bold User input appears in list bold type and must be entered iv exactly as shown Names of directories files commands options and man page references also a
188. arked lines and exit ESC exit without changing the marked lines mark or unmark all displayed lines to be changed In this case enter 2 3 and 4 Note that the numbers you type are not printed on the screen Instead cscope marks each list item you want to be changed by printing a gt greater than symbol after its line number in the list 9 15 Compilation Systems Volume 1 Tools Change 100 to MAXSIZE File Line T e err c 19 p total As00 get p rcentaga Zaina BEL RS IB a0 oe A Snake a ehar EOL Ana E26 For 0 NO poread 2er S ADH N OTO Find this C symbols Find this global definition Find functions called by this function Find functions calling this function Find this text string Change this text string Find this egrep pattern Find this file Find files including this file Select lines to change press the key for help Screen 9 12 Marking Lines to Be Changed Now press Ctrl d to change the selected lines cscope displays the lines that have been changed and prompts you to continue Changed lines char s MAXSIZE for i O7 AMAS ELE if c lt MAXSIZE Press the RETURN key to continue Screen 9 13 cscope Displays Changed Lines of Text 9 16 Browsing Through Your Code with cscope When you press RETURN in response to this prompt cscope redraws the screen restoring it to its state before you selected the lines to be changed as shown in the screen below
189. ars on the left of the line and separated by one or more spaces its definition or translation appears on the right When you later use abbreviations in your rules be sure to enclose them within braces Abbreviations avoid needless repetition in writing your specifications and make them easier to read As an example reconsider the lex source reviewed at the beginning of this section on advanced lex usage The use of definitions simplifies our later reference to digits letters and blanks This is especially true if the specifications appear several times Start Conditions Lexical Analysis with lex poc a zA Z ANETO printf negative integer printf positive integer printf negative fraction printf may have a G word here printf railroad is one word print eriminal y rail B road crook Some problems require for their solution a greater sensitivity to prior context than is afforded by the operator alone You may want different rules to be applied to an expression depending on a prior context that is more complex than the end of a line or the start of a file In this situation you could set a flag to mark the change in context that is the condition for the application of a rule then write code to test the flag Alternatively you could define for lex the different start conditions under which it is to apply each rule Consider this problem copy the input to the output except change the word magic to t
190. as mfspr rT 771 Move From Performance Monitor Counter 2 604 e 620 only Supervisor Level Same as mfspr rT 954 Move From Performance Monitor Counter 2 Read Only 620 only Same as mfspr rT 772 Move From Performance Monitor Counter 3 604e only Supervisor Level Same as mfspr rT 957 Move From Performance Monitor Counter 4 604e only Supervisor Level Same as mfspr rT 958 Move From Processor Version Register Supervisor Level Same as mfspr rT 287 Move From Required Physical Address 602 603 e only Supervisor Level Same as mfspr rT 982 Move From Real Time Clock Lower 601 only s Same as mfspr rT 5 Move From Real Time Clock Upper 601 only Same as mfspr rT 4 Move From Sampled Data Address Register 604 e 620 only Supervisor Level Same as mfspr rT 959 Move From Storage Description Register 1 Supervisor Level Same as mfspr rT 25 Move From Special Execute Base Register 602 only Supervisor Level Same as mfspr rT 990 Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC Mnemonic Syntax of Operands RS 6000 Description POWER Mnemonic mfser mfsia mfsp mfspr mfsprg mfsrin mfsrrO mfsrr1 mftb mftbl mftbu mftcr mfthrm1 1T 1T IT rT SPR rT n rLSR T rB T T T TBR T T T T Move From Special Execute Register 602 only Supervisor Level Same as mfspr rT
191. at are difficult for yace to handle are also frequently difficult for human beings to handle Some users have reported that the discipline of formulating valid yace specifications for their input revealed errors of conception or design early in program development The remainder of this chapter describes the following subjects Basic process of preparing a yace specification Parser operation Handling ambiguities Handling operator precedences in arithmetic expressions Parsing with yacc Error detection and recovery e The operating environment and special features of the parsers yace produces Suggestions to improve the style and efficiency of the specifications Advanced topics In addition there are two examples and a summary of the yace input syntax Basic Specifications Names refer to either tokens or non terminal symbols yacc requires token names to be declared as such While the lexical analyzer may be included as part of the specification file it is perhaps more in keeping with modular design to keep it as a separate file Like the lexical analyzer other subroutines may be included as well Thus every specification file theoretically consists of three sections the declarations grammar rules and subrou tines The sections are separated by double percent signs the percent sign is generally used in yacc specifications as an escape character A full specification file looks like declarations oo
192. atable object files Temporary files are used during assembly If the TMPDIR environment variable is defined these files are placed under this directory If it is not defined the var tmp directory is used if it is available otherwise tmp is used Temporary files are removed by the assembler upon completion of assembly Using the Assembler Assembler Invocation The assembler is invoked as as options file The options are listed below f float Use float as the floating point mode of assembly and the object file Desired Mode Acceptable Argument Values IEEE COMPATIBLE 3 ieeecom IEEE NEAREST 4 ieeenear near ieee IEEE ZERO ieeezero zero 5 IEEE POS INFINITY 6 ieeepos pos 7 IEEE NEG INFINITY ieeeneg neg m Run the m4 macro preprocessor on the input to the assembler o objfile QTARGET PPC601 QTARGET PPC603 QTARGET PPC604 Assembler and Assembly Language Put the output of the assembly in objfile by default The output file name is formed by removing the s suffix if there is one from the input file name and appending a o suffix Accept certain extensions to the Ada language 1 Allow a string enclosed in double quotes to appear in an identifier provided the first character of the identifier is not a double quote The characters normally allowed in an identifier may appear in the quoted string Additionally the characters lt gt and amp may appear in the quoted
193. atic fun f1 c 3 i fl cu equality operator found where was expected Format Simple An equality operator was found where a side effect was expected 10 18 Analyzing Your Code with lint void fun a b int a bs a b for a b a lt 10 att warning equality operator found where was expected warning equality operator was expected found where evaluation order undefined name Format Simple A variable was changed by a side effect and used elsewhere in the same expression int a 10 main int i 5 alit i warning evaluation order undefined i fallthrough on case statement Format Simple Execution fell through one case to another without a break or return Preceding a case statement with FALLTHRU or NOTREACHED when the case cannot be reached from the preceding case see below suppresses the message for that statement invoking lint with h suppresses it for every statement 1 2 3 4 5 6 7 8 9 10 EE 12 13 14 void fun i switch i case 10 i 0 case 12 return case 14 break case 15 case 16 break case 18 10 19 Compilation Systems Volume 1 Tools 15 FALLTHRU 16 case 20 17 error bad number 18 NOTREACHED 19 case 22 20 return 21 22 6 warning fallthrough on case statement function argument number Format Compound declared inco
194. ations except for the first token in the first statement This token must be seen by 7 25 Compilation Systems Volume I Tools the parser before it can tell that the declaration section has ended and the statements have begun In many cases this single token exception does not affect the lexical scan This kind of back door approach can be elaborated to a noxious degree Nevertheless it represents a way of doing some things that are difficult if not impossible to do otherwise Reserved Words Some programming languages permit you to use words like if which are normally reserved as label or variable names provided that such use does not conflict with the valid use of these names in the programming language This is extremely hard to do in the framework of yacc It is difficult to pass information to the lexical analyzer telling it this instance of if is a keyword and that instance is a variable You can make a stab at it using the mechanism described in the last subsection but it is difficult Advanced Topics This part discusses a number of advanced features of yacc Simulating error and accept in Actions The parsing actions of error and accept can be simulated in an action by use of macros YYACCEPT and YYERROR The YYACCEPT macro causes yyparse to return the value 0 YYERROR causes the parser to behave as if the current input symbol had been a syntax error yyerror is called and error recovery takes place These mechanisms
195. atl v v v v v mfibatu v v v v v mfibr v mficmp v v mfimiss v v mfl2cr v mfl2sr v mflt v mfmmcrO v v v mfmmcrOrd v mfmmerl 604e v mfmq v mfpir v v v mfpmcl v v v mfpmc 1rd v mfpmc2 v v v mfpmc2rd v mfpmc3 604e v mfpmc4 604e v 3 33 Compilation Systems Volume 1 Tools Table 3 7 Implementation Specific and Optional Instructions Cont Mnemonic 601 602 603 e 604 e 620 750 mfrpa v v mfricl v mfricu v mfsda v v x mfsebr x mfser mfsia v v v mfsp mftb mftbl mftbu ISIS x x x mftcr mtasr v mtbatl v mtbatu v mtbuscr mtdabr v mtdbatl v v mtdbatu v v mtear v v S S88 ISIS S S S S x mtesasrr S mtfpecr mthidO v mthidl v mtiabr v x x x mtibatl x x x S S S S S mtibatu S S S S S S x x x mtibr mtl2cr v mtl2sr v milt v mtmmcrO v v v mimmcrl 604e v 3 34 PowerPC Instruction Set Summary Table 3 7 Implementation Specific and Optional Instructions Cont Mnemonic 601 602 604 e 620 750 mtmq mtpir mtpmc1 mtpmc2 mtpmc3 mtpmc4 mtrpa mtrtcl mtrtcu mtsda mtsebr mtser mtsia mtsp mtsrd mtsrdin or mtsrind mttb mttbl mttbu mttcr mul o I mulhd mulhdu mulld o nabs o I ridcl ridcr ridic ridicl ridicr rldimi rimi v v S S S S 604e 604e S S S S S S S S S S S 3 35 Compilation Systems Volume 1 Tools Table 3 7 Implementa
196. bc a The contents of 1ibm are described in Chapter 16 Run Time Libraries Note finally that because the link editor searches an archive library only to resolve undefined external references it has previously seen the placement of the 1 option on the cc command line is important That is the command cc Zlink static filel c lm file2 c file3 c will direct the link editor to search libm a only for definitions that satisfy still unresolved external references in filel c As a rule then it s best to put 1 at the end of the command line Creating and Linking with Archive and Shared Object Libraries In this subsection we describe the basic mechanisms by which archives and shared objects are built The idea is to give you some sense of where these libraries come from as a basis for understanding how they are implemented and linked with your programs Of course if you are developing a library you will need to know the material in this subsection Even if you are not it should prove a useful introduction to the subsequent discussion The following commands cc c functionl c function2 c function3 c ar r libfoo a functionl o function2 o function3 o will create an archive library libfoo a that consists of the named object files Check the ar 1 manual page for details of usage When you use the 1 option to link your program with libfoo a cc L dir filel c file2 c file3 c lfoo the link editor will incorporate in
197. bea tet tte 11 9 UA Led ee 11 10 Assumptions and Constraints Compilation Systems Volume 1 Tools Introduction analyze Information 11 Performance Analysis An analysis of the run time performance and characteristics of a program can identify sections of code which have a significant effect on the speed and behavior of the program PowerUX provides a tool which can be used to obtain an execution profile of any pro gram Two traditional UNIX tools provide profile data for a program which has been compiled to produce this data during execution The output from prof identifies which routines in the program have been executed how often they were invoked and what percentage of the program s execution time was spent in each routine The gprof tool additionally pro vides a call graph of the ancestors and descendants of the routines These tools are not available on supported hardware platforms Better information can be obtained through a Concurrent developed tool called analyze Where prof and gprof require a special compilation of a program for producing profile data analyze operates on already compiled code It may be necessary to invoke analyze through a link edit step but recompilation of the program is not necessary analyze first reads an executable file It then interprets the instructions in this file to find the routines and basic blocks a block is a sequence of instructions having one entry and one exit point within each
198. ble Entry Index 0 000 22 14 Section Attribute Flags sh_flagS 0ooooooooocoocmoomo oo 22 14 sh_link and sh info Interpretation 220 0 0 cece ee eee 22 15 xxiii Compilation Systems Volume 1 Tools xxiv Table 22 11 Table 22 12 Table 22 13 Table 22 14 Table 22 15 Table 22 16 Table 22 17 Table 22 18 Table 22 19 Table 22 20 Table 22 21 Table 22 22 Table 22 23 Table 22 24 Table 22 25 Table 22 26 Table 22 27 Table 22 28 Table 22 29 Table 22 30 Table 22 31 Table 22 32 Table 22 33 Table 22 34 Table 22 35 Table 22 36 Table 22 37 Table 22 38 Table 22 39 Table 22 40 Table 22 41 Table 24 1 Table 24 2 Table 24 3 Table 24 4 Table 24 5 Table 24 6 Table 24 7 Table 24 8 Table 24 9 Table 24 10 Table 24 11 Table 24 12 Table 24 13 Table 24 14 Table 24 15 Table 24 16 Table 24 17 Table 24 18 Table 24 19 Table 24 20 Table 24 21 Table 24 22 Table 24 23 Special Sections u bose ee RR DAR DRE 22 15 Vendor Section Rounding Modes round mode 22 19 Vendor Section Floating Point Exceptions Kind fp except kind 22 19 Vendor Section Enabled Exceptions float exceptions 22 20 Vendor Section PowerPC Features IBM_mode 22 20 Vendor Section Extended Double Precision Use float precision 22 21 Vendor Section Process Private Data Pointer Use ppdp used 22 21 Vendor
199. block report to only the first number basic blocks If the number is written with a trailing character on the end then it will restrict the list of blocks printed to just the first set of blocks that total to that percent of the total time This option implies the use of the b option Both forms of the B option may be used in which case the first limit reached will terminate the listing c List the names of routines called by each routine d range Select which data sets to report Each time a patched program is run it appends a new set of profile data onto the end of its profile data file This means that one data file may contain several sets of data The first set is set number one This option may be used to select which sets are actually reported Range can be a single number a list of comma separated numbers or a range of numbers separated with a dash i Report summary information for the complete program This option uses the assumed clock rate specified with the M option to report the clock time the original program would take to run It also summarizes the count of the different types of instructions that were executed 1 Use max time instead of min time when sorting statistics and computing percentages m Print timing information in milliseconds rather than cycles M megahertz Specify the megahertz clock rate to assume when computing clock time from cycle counts The default is 100 11 10 n N number
200. broutine and the values of data variables visible only to the current subroutine Some computer architectures provide hardware support for stack frames Modern architectures have made the stack frame a software concept leaving control of stack frames to the executable program Compilers then generate code which causes each sub routine to create update and remove its own stack frame The absence of hardware support for stack frames would make it virtually impossible for a debugger to produce a stack traceback which is an identification of the invocation order of subroutines at any point in time during execution of the program Concurrent compilation systems are able to support stack tracebacks through the use of text description information or tdesc This information embedded within an executable program describes pertinent portions of subroutines to the debugger Static and Dynamic Linking 1 6 Programs may be developed under PowerUX with static linking or dynamic linking A statically linked program contains all of the code and data it will need during execution The link editor supplies the program with these necessary components A dynamically linked program does not contain all of the code and data it will need during execution The link editor statically links a portion of the code and data into the executable program When the program begins execution a program interpreter dynamically links into the executing program s proces
201. bss section 2 1 2 11 2 17 byte directive 2 14 comm directive 2 17 comment section 2 18 2 19 data directive 2 13 data section 2 1 2 3 2 11 2 13 def directive 2 16 double directive 2 16 extern directive 2 16 file directive 2 18 float directive 2 15 globl directive 2 16 int directive 2 15 long directive 2 15 org directive 2 12 rela_ section 2 2 set directive 2 16 short directive 2 14 space directive 2 12 symtab section 2 2 text directive 2 13 text section 2 1 2 5 2 11 2 13 vbyte directive 2 14 word directive 2 14 etc group file 16 15 etc mnttab 16 14 etc passwd 16 14 etc shadow file 16 15 letc vfstab 16 13 tmp directory 2 2 usr lib 4 15 4 16 var adm utmp 16 16 var adm utmpx 16 16 var adm wtmp 16 16 var adm wtmpx 16 16 var tmp directory 2 2 Index A Access control list functions 16 51 acpp 1 1 4 Ada 2 3 Ada compiler 1 4 Ada programming language 1 2 ada 1 1 4 adb 1 1 4 Address mode determination 20 16 20 17 Address modes 20 17 admin 1 14 2 14 9 14 19 14 21 14 28 14 29 Algebraic simplification 20 16 20 17 align directive 2 12 2 17 Alphanumeric labels 2 4 Alternate math library 16 2 Analyze detecting references to reserved registers 20 25 optimizing programs during post linking stage 20 25 analyze 1 1 4 ar 1 1 4 4 11 Archive 1 3 archive libraries 4 9 implementation 4 17 linking with 4 9 4 15 4 35 archive libraries creating creating 4 11 archive librari
202. c 11 Alternatively you may want to write your own driver The following is similar to the library version extern int yylex int yywrap return 1 main while yylex r We ll take a closer look at the function yywrap in lex Routines on page 6 10 For now it s enough to note that when your driver file is compiled with lex yy c cc lex yy c driver c its main will call yylex at run time exactly as if the lex library had been loaded The resulting executable reads st din and writes its output to st dout Figure 6 1 shows how lex works Lexical Analysis with lex lexical lex source 9 lex analyzer code C compiler lexical output input tokens text program text etc Figure 6 1 Creation and Use of a Lexical Analyzer with lex Writing lex Source lex source consists of at most three sections definitions rules and user defined routines The rules section is mandatory Sections for definitions and user routines are optional but if present must appear in the indicated order definitions 22 00 rules oo user routines The Fundamentals of lex Rules The mandatory rules section opens with the delimiter If a routines section follows another delimiter ends the rules section The delimiters must be entered at the beginning of a line without leading blanks If there is no second delimiter the rules section is presumed to continue to the end of
203. cation division The integer quotient is returned with truncation performed on the real value amp bitwise AND bitwise OR bitwise XOR bitwise NOR a b is equivalent to a OR NOT b lt logical left shift a lt b is a shifted left b bits gt arithmetic right a gt b is a shifted right b bits shift unary negation one s complement Operator Precedence The precedences of the operators appear next 0 highest unary M ne Is Sips S EE binary lowest Binary operators of the same precedence are left to right associative Parentheses may be used to override the default precedences and or associativity 2 10 Assembler and Assembly Language Expression Types The type of an expression depends upon the types of the operators and the operands The possible expression and identifier types are manifest The value can be computed by the assembler at the time of its appearance absolute The value can be computed by the assembler though not necessarily at the time of its appearance relocatable The value is relative to the start of a particular section The memory location represented by the expression is not known at assembly time but the relative values of two such expressions are known if they refer to the same section undefined external No value is assigned to the expression It is expected that the values will be determined at link time The relative values of undefined
204. cified with r The string following y or m is used to check the value set by the t or m flag respectively See admin 1 for descriptions of these flags The val command treats the special argument hyphen differently from other SCCS commands It allows val to read the argument list from the standard input instead of from the command line and the standard input is read until an end of file control d is entered This permits one val command with different values for key letters and file arguments For example val yc mabc s abc mxyz ypll s xyz control d first checks if file s abc has a value c for its type flag and value abc for the module name flag Once this is done val processes the remaining file in this case s xyz The val command returns an 8 bit code Each bit set shows a specific error see val 1 for a description of errors and codes In addition an appropriate diagnostic is printed unless suppressed by s A return code of 0 means all files met the characteristics speci fied This section covers protection mechanisms used by SCCS the format of SCCS files and the recommended procedures for auditing SCCS files SCCS relies on the capabilities of the UNIX system for most of the protection mechanisms required to prevent unauthorized changes to SCCS files that is changes by non SCCS commands Protection features provided directly by SCCS are the release lock flag the release floor and ceiling flags
205. containing LINTED msg Options and Directives Listed 10 8 These options suppress specific messages a Suppress assignment causes implicit narrowing conversion conversion to larger integral type may sign extend incorrectly m u v X Analyzing Your Code with lint For unreachable break and empty statements suppress statement not reached Suppress assignment operator n found where equality operator was expected constant operand to op fallthrough on case statement pointer cast may result in improper alignment precedence confusion possible parenthesiz statement has no consequent if statement has no consequent else Suppress declared global could be static Suppress name defined but never used name used but not defined Suppress argument unused in function Suppress name declared but never used or defined These options enable specific messages TP Enable conversion to larger integral type may sign extend incorrectly may be indistinguishable due to truncation or case pointer casts may be troublesome nonportable bit field type suspicious comparison of char with value op op 10 9 Compilation Systems Volume 1 Tools 10 10 Xc Enable bitwise operation on signed value nonportable function must return int main may be indistinguishable due to truncation or case only 0 or 2 parameters allowe
206. cope for each set of source files the cross reference information for the two programs is kept separate You can use the pn option to specify that cscope display the path name or part of the path name of a file when it lists the results of a search The number you give to p stands for the last n elements of the path name you want to be displayed The default is 1 the name of the file itself So if your current directory is home common the command cscope p2 will cause cscope to display common filel c common file2 c and so forth when it lists the results of a search 9 11 Compilation Systems Volume 1 Tools 9 12 If the program you want to browse contains a large number of source files you can use the b option to tell cscope to stop after it has built a cross reference cscope will not display a menu of tasks When you use cscope b in a pipeline with the batch com mand cscope will build the cross reference in the background echo cscope b batch NOTE See batch 1 for more information Once the cross reference is built and as long as you have not changed a source file or the list of source files in the meantime you need only specify cscope for the cross reference to be copied and the menu of tasks to be displayed in the normal way In other words you can use this sequence of commands when you want to continue working without having to wait for cscope to finish its initial processing The d opti
207. ction of the object file contains the binary encodings of the assembly instructions in the source Historically this collection of bits and bytes has been referred to as machine language The data and the bss 1 See the Preface for details 2 1 Compilation Systems Volume 1 Tools sections contain the initialized and uninitialized data respectively The symtab section contains information about all of the symbols present in the assembly source The rela_ sections provide relocation information to the link editor enabling it to combine this relocatable object file with other such files to form an executable program The assembler processes only one input file on each invocation Traditionally the name of an input file ends with the suffix s although any valid UNIX name is acceptable The o option can be used to specify the name of the output object file If this option is not used the assembler names the output file according to the following rules Ifthe name of the input file ends in s then the name of the output file is the same as the name of the input file but with s replaced with o Ifthe name of the input file does not end in s then the name of the output file is the same as the name of the input file but with o appended The C Fortran and Ada compilers produce assembly language source file s as their compiled output They then invoke the assembler to convert the assembly source files into reloc
208. d main nonportable character constant Other options c Create a 1n file consisting of information relevant to 1int s second pass for every c file named on the command line The second pass is not executed F When referring to the c files named on the command line print their path names as supplied on the command line rather than only their base names Idir Search the directory dir for included header files k When used with the directive LINTED msg print info msg 1x Access the lint library 1lib 1x 1n Ldir When used with 1 search for a Lint library in the directory dir n Suppress checks for compatibility with the default lint standard C library ox Create the file 11ib 1x 1n consisting of information relevant to lint s second pass from the c files named on the command line Generally used with yor LINTLIBRARY to create lint libraries s Convert compound messages into simple ones y Treat every c file named on the command line as if it began with the directive LINTLIBRARY V Write the product name and release to standard error Directives ARGSUSEDn Suppress argument unused in function for every argument but the first n in the function definition it precedes Default is 0 CONSTCOND Suppress constant in conditional context constant operand to op Analyzing Your Code with lint logical expression always false op amp amp logical express
209. d because it needs a resource The number at the end enclosed in brackets is the sequence number of the instruction which currently has the resource and is the cause of the block sir On the PowerPC platforms individual pipeline stages are not shown as allocated and freed Instead it is simply announced that a particular instruction has entered a particular stage with the s entry Usethe Zstage status option to cause analyze s output to include the status of all the pipeline stages each cycle While this output is much easier to read it is extremely verbose Note that instructions are disassembled at the cycle they enter dispatch Negative numbers in the stage status output are placeholders for pipeline bubbles caused by alignment constraints Screen 11 1 illustrates this situation den 0001028 3d000000 dis Top t 6 ON Ll 11 1000102c 39200000 dne 9p t 6 t 6 Fetch 16 Ey 18 19 Decode 3592 Ss 14 15 Dispatch 8 9 10 Pr SCUIUT SCHU2 MCIU ERU LSU BPU Q2 ipee icm exem gt Ql nas Se SPRIT Sa Ss X1 6 7 gt ae gt X2 gt SSS SS eyes x3 eS ard Finished 4 5 Complete 4 5 Writeback GPR A5 EPRZ CERIS d Screen 11 1 Sample Output from analyze When analyze prints an instruction out it puts it on a line by itself with the clock time it started execution on the end The fields on the line represent the source line number blank if no debug information is available in the fil
210. d but not used or defined in any file The message is suppressed when lint is invoked with x 10 27 Compilation Systems Volume 1 Tools file c 1 extern int fun 2 static int foo name declared but never used or defined fun fuel name defined but never used Format Compound A variable or function was defined but not used in any file The message is suppressed when lint is invoked with u file c 1 int i j k 1 2 main 3 4 jk 5 name defined but never used i fise 39 name multiply defined Format Compound A variable was defined in more than one source file file 1 c 1 char i a file 2 c 1 long i 1 name multiply defined j ENSI ACA name used but not defined Format Compound Anon static external variable or function was declared but not defined in any file The message is suppressed when lint is invoked with u 10 28 Analyzing Your Code with lint file c 1 extern int fun 2 int main 3 4 return fun 5 name used but not defined fun c 4 nonportable bit field type Format Simple A bit field type other than signed int or unsigned int was used The message is issued only when lint is invoked with p Note that these are the only portable bit field types The compilation system supports int char short and long bit field types that may be unsigned signed or plain It also supports the enum bit field type
211. d by the effective user It exists only for the duration of the execution of the command that creates it When processing is complete the contents of s file are replaced by the contents of x file whereupon x file is destroyed To prevent simultaneous updates to an SCCS file the same modifying commands also create a lock file called z file z file contains the process number of the command that creates it and its existence prevents other commands from processing the SCCS file z file is created with access permission mode 444 read only for owner group and other in the same directory as the SCCS file and is owned by the effective user It exists only for the duration of the execution of the command that creates it In general you can ignore these files They are useful only in the event of system crashes or similar situations SCCS commands produce error messages on the diagnostic output in this format ERROR file message text code The code in parentheses can be used as an argument to the help command to obtain a further explanation of the message Detection of a fatal error during the processing of a file causes the SCCS command to stop processing that file and proceed with the next file specified SCCS Commands 14 8 This section describes the major features of the fourteen SCCS commands and their most common arguments Here is a quick reference overview of the commands get 1 Retrieves versions of SCCS files
212. definition functions called by this function functions calling this function EMS test Stringi Change this text string Find Find Find this egrep pattern this file files including this file Screen 9 1 The cscope Menu of Tasks Press the RETURN or Enter key to move the cursor down the screen with wraparound at the bottom of the display and Ctrl p to move the cursor up or use the up arrow and down arrow keys if your keyboard has them You can manipulate the menu and perform other tasks with the following single key commands Table 9 1 Menu Manipulation Commands TAB move to next input field RETURN move to next input field Ctrl n move to next input field Ctrl p move to previous input field Ctrl y search with the last pattern typed Ctrl b move to previous input field and search pattern Ctrl f recall next input field and search pattern Ctrl c toggle ignore use letter case when searching a search for FILE will match for example File and file when ignoring letter case Ctrl r rebuild the cross reference start an interactive shell type Ctrl d to return to escope 9 3 Compilation Systems Volume 1 Tools 9 4 Table 9 1 Menu Manipulation Commands Cont Ctrl redraw the screen 2 display list of commands Ctrl d exit cscope If the first character of the text for which you are searching matches one of these commands you can escape the command by entering a backslash 1 bef
213. der version for dynamically linked executables that depend on it On the other hand you will want newly created executables to be linked with the updated version Moreover you will probably want both versions to be stored in the same directory In this situation you could give the new release a different name rewrite your documentation and so forth A better alternative would be to plan for the contingency in the very first instance by using the fol lowing sequence of commands when you create the original version of the shared object cc ZPIC Zlink so h libfoo 1 o libfoo 1 functionl c function2 c function3 c ln libfoo 1 libfoo so In the first command h stores the name given to it libfoo 1 in the shared object itself You then use the UNIX system command 1n 1 to create a link between the name 4 21 Compilation Systems Volume 1 Tools libfoo 1 and the name libfoo so The latter of course is the name the link editor will look for when users of your library specify cc L dir filel c file2 c file3 c lfoo In this case however the link editor will record in the user s executable the name you gave to h libfoo 1 rather than the name libfoo so That means that when you release a subsequent incompatible version of the library 1ibfoo 2 executables that depend on libfoo 1 will continue to be linked with it at run time As we saw earlier the dynamic linker uses the shared object name that is stored in the executable to sati
214. desc information if they have symbolic debug information identifying them as subroutine entry points or if they are explicitly named using the a option analyze records its profile statistics by writing them into the bss section The header of the object file is modified to reserve space in bss but the run time environment also needs to be informed that the space is being used analyze does this by first attempting to patch the initial value of the global variable curbrk used by the library routines to record the break address If this variable is not found in the symbol table it then attempts to patch a call to brk into the main entry point If it cannot find the brk entry point in the symbol table then it cannot successfully patch the program It may be necessary to re link the program forcing the brk routine to be included by linking in an additional object file that references it or use the Zbreak name option to specify a different name for the break variable Finally analyze writes the statistics out by patching in a call to the write routine when the exit routine is called that is two underscores If the low level exit routine is not called exit or if the program exits in a different way possibly by calling exec then you will need to use the X option to name the routines that should dump statistics After dumping the statistics at an exit point all the basic block counts are set to zero This feature allo
215. dified at run time If a process writes to a shared page in the course of relocating a reference to a shared object it gets a private copy of that page and loses the benefits of code sharing although without affecting other users of the page Third to create programs that require the least possible amount of page modification at run time the compiler generates position independent code under the ZPIC option Whereas executable code normally must be tied to a fixed address in memory position independent code can be loaded anywhere in the address space of a process Because the code is not tied to specific addresses it will execute correctly without page modification at a different address in each process that uses it As we have indicated you should specify ZPIC when you create a shared object cc ZPIC Zlink so o libfoo so functionl c function2 c function3 c Relocatable references in your object code will be moved from its text segment to tables in the data segment See Chapter 22 Executable and Linking Format ELF in this manual for the details In the next subsection we ll look at some basic guidelines for building shared objects For now we ll sum up the reasons why you might want to use one Because library code is not copied into the executables that use it they require less disk space Because library code is shared at run time the dynamic memory needs of systems are reduced Because symbol resolution is
216. dling of prior context lex uses the symbol as an operator to mark a special trailing context the end of a line An example would be a rule to ignore all blanks and tabs at the end of a line L t which could also be written t n On the other hand if you want to match a pattern only when it starts a line or a file you can use the operator Suppose a text formatting program requires that you not start a line with a blank You might want to check input to the program with some such rule as evan printf error remove leading blank Note the difference in meaning when the operator appears inside the left bracket as described in Operators on page 6 4 Some of your action statements themselves may require your reading another character putting one back to be read again a moment later or writing a character on an output device lex supplies three macros to handle these tasks input unput c and output c respectively One way to ignore all characters between two special characters say between a pair of double quotation marks would be to use input thus Nn while input f NU Upon finding the first double quotation mark the scanner will simply continue reading all subsequent characters so long as none is a double quotation mark and not look for a match again until it finds a second double quotation mark See the further examples of input and unput c usage in User Routines on page 6 1
217. ds floating point constants and the arithmetic operations and unary It uses the registers a through z Moreover it understands intervals written X Y where X is less than or equal to Y There are 26 interval valued variables A through Z that may also be used The usage is similar to that in Example 1 assignments return no value and print nothing while expressions print the floating or interval value This example explores a number of interesting features of yace and C Intervals are represented by a structure consisting of the left and right endpoint values stored as doubles This structure is given a type name INTERVAL by using typedef The yacc value stack can also contain floating point scalars and integers used to index into the arrays holding the variable values Notice that the entire strategy depends strongly on being able to assign structures and unions in C language In fact many of the actions call functions that return structures as well It is also worth noting the use of YYERROR to handle error conditions division by an interval containing 0 and an interval presented in the wrong order The error recovery mechanism of yacc is used to throw away the rest of the offending line In addition to the mixing of types on the value stack this grammar also demonstrates an interesting use of syntax to keep track of the type for example scalar or interval of intermediate expressions Note that scalar c
218. e with respect to print file FILES pe 22 Jo Fe touch print The make program prints out each command before issuing it The following output results from entering the command make in a directory containing only the source and description files 13 4 Parallel make Managing File Interactions with make main c doname c misc Cc files c dosys c yacc gram y mv y tab c gram c CELO CEST ams cc o make main o doname o misc o files o dosys o gram o 13188 3348 3044 19580 The last line results from the size make command The printing of the command line itself was suppressed by the symbol in the description file If make is invoked with the P option it tries to build more than one target at a time in parallel This is done by using the standard UNIX system process mechanism which enables multiple processes to run simultaneously prog x o y O Zz O ES SO CyeOs Czuoto Im o prog X 0 X C defs h CS TE XC y o y c defs h ES pce YE Z0 5 o EG FE ESO For the makefile shown above it would create processes to build x o y o and z oin parallel After these processes were complete it would build prog The number of targets make will try to build in parallel is determined by the value of the environment variable PARALLEL If P is invoked but PARALLEL is not set then make will try to build no more than two targets in parallel You can use the MUTEX directive to serial
219. e the sequence number within the block the absolute address of the instruction in the file the four byte hex for the instruction itself then the symbolic disassembly of the instruction Currently max time is defined as the total number of cycles required for all instructions in the block to make it through all pipe stages It therefore represents a worst case upper bound 11 2 Statistics Profiling Performance Analysis Note that all times are local a block containing a subroutine call will only have the time for the call instruction No information is computed about the time actually spent in the subroutine and no information is known about the state of the pipelines when the subrou tine returns The max time for a block ending in a subroutine call does not count any cycles remaining in the pipe at the time the call is made because most of these cycles never cause any delay the subroutine is usually still in the prologue when the pipe drains The optimization features of analyze can be invoked at link edit time by using the Con current link editor s O option Refer to 1d 1 and Chapter 20 Program Optimiza tion for more information The analyze tool computes several statistics some of which are more meaningful than others but all are designed to help someone analyze the quality of generated code BURT BURT stands for Bogus Uniform Routine Time and as its name indicates is a fairly bogus statistic whic
220. e The optional third argument alignment is of manifest type and must be a power of two It has the meaning as alignment in the align directive above If alignment is not specified the alignment of identifier is 1 or 2 when size is 1 or 2 respectively otherwise the alignment is to an 8 byte boundary For example comm block 20 define a common area block of size 20 bytes on an 8 byte boundary bss bss identifier size alignment identifier is made externally invisible but internally visible It is size bytes long and is assigned to the bss section alignment is optional and must be a power of two if present If alignment is missing the alignment is regarded as 1 byte Both size and alignment are of manifest type For example bss var 10 4 define a bss variable var size 10 bytes on a 4 byte boundary local identifier identifier Each identifier is defined in the input file and not accessible to other files Any default binding for identifier is overridden by this directive For example local local var declare a local variable local var weak identifier identifier Each identifier is declared to be a weak global identifier It is either defined externally or defined in the input file and accessible in other files Any default binding for identifier is overridden by this directive For example weak sub give sub weak binding NOTE The assembler permits
221. e set of rules that you write In the following lexical analyzer example the reserved word end could match the second rule as well as the eighth the one for identifiers Lexical Analysis with lex begin return end return while return E return package return reverse return loop return a zA Z a zA Z0 9 STO return 0 9 eO return EO return MO return MEO return Af ES return BEGIN END WHILE LEEY PACKAGE REVERSE LOOP putz in tabi 0 IDENTIFIER put_in_tabl INTEGER PLUS ARITHOP MINUS ARITHOP GREATER RELOP GREATEREOL RELOP lt lt lt lt lt lt SS aaa ona lex follows the rule that where there is a match with two or more rules in a specification the first rule is the one whose action will be executed By placing the rule for end and the other reserved words before the rule for identifiers we ensure that our reserved words will be duly recognized Another potential problem arises from cases where one pattern you are searching for is the prefix of another For instance the last two rules in the lexical analyzer example above are designed to recognize gt and gt If the text has the string gt at one point you might worry that the lexical analyzer would stop as soon as it recognized the gt character and execute the rule for gt rather than read the next character and execute the rule for b
222. e 1 Tools 16 27 regular expressions 6 4 6 6 relocatable files see also object files 4 9 22 1 Relocatable object file 1 3 2 1 2 2 relocation 22 27 report 1 1 4 rmdel 1 14 9 14 23 14 24 S sact 1 14 9 14 23 sbyte directive 2 14 SCCS 14 1 14 29 SCCS auditing files 14 28 14 29 SCCS changing comments 14 24 SCCS changing file parameters 14 19 14 20 14 21 SCCS commands 14 7 14 26 SCCS creating files 14 2 14 19 14 21 SCCS file format 14 27 14 28 SCCS file protection 14 26 14 27 SCCS ID keywords 14 10 SCCS marking differences 14 19 14 25 SCCS printing files 14 21 14 23 SCCS removing versions 14 23 14 24 SCCS retrieving files 14 2 14 3 14 9 14 17 SCCS updating files 14 3 14 17 14 19 SCCS usage example 14 2 14 4 SCCS use with make 1 13 13 13 14 SCCS version numbering 14 5 14 7 sccsdiff 1 14 9 14 25 Section bss 2 1 2 11 2 17 comment 2 18 2 19 data 2 1 2 3 2 11 2 13 rela_ 2 2 symtab 2 2 text 2 1 2 5 2 11 2 13 section directive 2 13 Security functions 16 50 Selecting compiler optimization levels 20 2 Semaphore functions 16 33 Separate lifetimes 20 12 20 15 set directive 2 16 Shadow password file functions 16 15 shalf directive 2 15 Shared library 1 6 Shared memory functions 16 30 Shared object 1 6 Shared object functions 16 22 shared objects 4 8 guidelines for building 4 18 4 22 implementation 4 17 4 18 22 27 22 45 Index 10 linking with 4 9 4 16 4 35 shared objects
223. e 14 26 Protection 22 6 s oer Aiea oad teeth es ET ue ee Le IL t efe ee hts nar t cts 14 26 Formatting sese a NAME S OR PP Re 14 27 Auditing eee e RR E eta RR nts 14 28 Index Part4 Environments Chapter 15 Introduction to Environments Introduction 2o doo Re nA e E bere dee ee ee re 15 1 Chapter 16 Run Time Libraries Introduction cocer lem cde RD re E Reis 16 1 System T abraries eel 32222 eI EE te e ace 16 1 C Library aan ERR ee RE eR neat 16 1 Alternate C Library 2 2 44 ee ee Pee 16 2 Math Library cosa a rn ae 16 2 Alternate Math Eibr ry 2 2 erba A 16 2 ELF Library esse eat a na 16 3 xiii Compilation Systems Volume 1 Tools DWARF Library 1 1 MR ea RR RIEN e 16 3 General Purpose Library oooooocoococororr rennen 16 3 Including Functions and Data 0 0 eee eese 16 3 Including Declarations 00 eee eee I 16 4 Listing of Functions iii seem ee eee a a ge 16 4 Input Output Control 22 ce eee eee 16 4 File and I O Control and Access 0 0 00 cece eee eee 16 5 Fileand VO Status ocupa e ar pe 16 6 Directories uel ae en en 16 7 File Systems a e eee dee coi e le pe t 16 7 General Input 0 0 5 0 cw seen e ue bin 16 8 General Output 5i ue tee SiMe Manette dente ee 16 9 Terminal VO oi nes 16 10 STREAMS iie t tree bi Mete ce react de e ice un 16 11 Pipes add FIFOS 22 ee aa 16 12 DEVICES san e CL e eda ete pata 16 12 Special Files ston tease we ee ago ee A
224. e Set appropriate fields in the vendor section so that the machine state register msr is initialized on program start up to indicate the kind of floating point exceptions that can be taken value can be imprecise floating point exceptions are imprecise and non recoverable precise floating point exceptions are pre cise and recoverable or disabled floating point exceptions do not occur The default mode is imprecise If any input module contains floating point code that is executed speculatively see chapter 20 the executable program should be link edited with the Qfpexcept disabled option Without this option floating point exceptions could be raised erroneously QG Same as G QGOTP TO GOT Implicitly convert GOTP relocation to GOT relocation during link editing This permits the static linking of files that have been built to be link edited into shared objects For improved performance however these object files should be rebuilt without the com pile time ZPIC option QLD RUN PATH ile Accept from file a list of library search directories for the dynamic linker The list is specified as it would be for the LD RUN PATH environment variable This option overrides use of the environment variable and is useful when the list is too long for the environment variable See the discussion of library search directories later in this section Qload file Accept a list of input object files shared objects and archives from
225. e compiler Lint also identifies mismatches of conversion specifications and arguments in fs printf and fs scanf control strings Examples Within files lint flags non void functions that fall off the bottom Portability Checks without returning a value to the invoking function In the past programmers often indicated that a function was not meant to return a value by omitting the return type fun That convention means nothing to the compiler which regards fun as having the return type int Declare the function with the return type void to eliminate the problem Across files lint detects cases where a non void function does not return a value yet is used for its value in an expression and the opposite problem a function returning a value that is sometimes or always ignored in subsequent calls When the value is always ignored it may indicate an inefficiency in the function definition When it is sometimes ignored it s probably bad style typically not testing for error conditions If you do not need to check the return values of string functions like strcat strcpy and sprintf or output functions like printf and putchar cast the offending call s to void lint identifies variables or functions that are declared but not used or defined used but not defined or defined but not used That means that when lint is applied to some but not all files of a collection to be loaded together it will complain about functions
226. e defined as one that compares two strings and returns yes or no respectively if they are the same or different define compare ifelse 1 2 yes no Note the quotes which prevent evaluation of ifelse from occurring too early If the final argument is omitted the result is null so ifelse a b c is c if a matches b and null otherwise ifelse can actually have any number of arguments and provides a limited form of multi way decision capability In the input ifelse a b c d e f g if the string a matches the string b the result is c Otherwise if d is the same as e the result is f Otherwise the result is g String Manipulation The 1en macro returns the length of the string number of characters in its argument len abcdef is 6 and len a b is 5 The substr macro can be used to produce substrings of strings If you type substr s i n it will return the substring of s that starts at the ith position origin 0 and is n characters long If n is omitted the rest of the string is returned If you type substr now is the time 1 it will return the following string now is the time If i or n are out of range a blank line is returned For example if you type substr now is the time 1 Or substr now is the time 1 39 5 9 Compilation Systems Volume 1 Tools Printing 3 10 you will get a blank line The index s1 s2 macro returns the index position in s 1 w
227. e edited g file If you are in the process of making a delta and the delta command finds no ID keywords in the edited g file the message No id keywords cm7 is issued after the prompts for commentary but before any other output This means that any ID keywords that may have existed in the SCCS file have been replaced by their values or deleted during the editing process This could be caused by making a delta from a g file that was created by a get without e ID keywords are replaced by get in such a case It could also be caused by accidentally deleting or changing ID keywords while editing the g file Or it is possible that the file had no ID keywords In any case the delta will be created unless there is an i flag in the SCCS file meaning the error should be treated as fatal in which case the delta will not be created After the processing of an SCCS file is complete the corresponding p file entry is removed from p file All updates to p file are made to a temporary copy q file whose Tracking Versions with SCCS use is similar to that of x file described in SCCS Command Conventions on page 14 7 If there is only one entry in p file then p file itself is removed In addition delta removes the edited g file unless n is specified For example delta n s abc will keep the g file after processing delta s suppresses all output normally directed to the standard output other than comments and MRs Thus use of
228. e entire path name in the mapfile in order to create a match More than one directive line may appear for a particular output segment e g the following set of directives is legal S1 SPROGBITS S1 SNOBITS Entering more than one mapping directive line for a segment is the only way to specify multiple values of a section attribute e A section can match more than one entrance criteria In this case the first segment encountered in the mapfile with that entrance criteria is used e g if a mapfile reads S1 SPROGBITS S2 SPROGBITS the SPROGBITS sections are mapped to segment 51 Extended Mapping Directives PowerUX mapfiles support an extension to the set of mapping directives described above These extensions permit the definition or redefinition of variables within a section These extended directives are output by the shmdefine 1 utility Size Symbol Declarations 4 28 Size symbol declarations let you define a new global absolute symbol that represents the size in bytes of the specified segment This symbol can be referenced in your object files A size symbol declaration has the following syntax segment name symbol name symbol name can be any legal C identifier although the 1d command does not check the syntax of the symbol name Mapping Example Link Editor and Linking Figure 4 1 is an example of a user defined mapfile The numbers on the left are included in the example for tutorial purpo
229. e how to and are comfortable with a purely formal presentation that scants motivation and background alike you may want to skip to Quick Reference Guide on page 4 35 Link editing refers to the process in which a symbol referenced in one module of your program is connected with its definition in another for example the process by which the symbol printf in an example source file hello cis connected with its definition in the standard C library The link editor uses two models of linking static or dynamic as governed by the d option or by the presence of the STATIC_LINK environment variable If this environment variable is not set then dynamic linking is the model used unless overridden by the dn option If this environment variable is set then static linking is the model used unless overridden by the dy option Whichever link editing model you choose static or dynamic the link editor will search each module of your program including any libraries you have used for definitions of undefined external symbols in the other modules If it does not find a definition for a symbol the link editor will report an error by default and fail to create an executable program Multiply defined symbols are treated differently however under each approach For details see Multiply Defined Symbols on page 4 22 The principal difference between static and dynamic linking lies in what happens after this search is completed Und
230. e ignores any other files appearing on the com mand line The I option to cscope is similar to the I option to cc By default cscope searches for included header files in the current directory then the standard place If you want cscope to search for an included header file in a different directory specify the path of the directory with I cscope I dir In this example cscope will search the directory dir for include files called into the source files in the current directory Directories are searched for include files in the following order 1 the current directory 2 the directories specified with I 3 the standard place for header files usually usr include You can invoke the I option more than once on a command line cscope will search the specified directories in the order they appear on the command line You can specify a cross reference file other than the default cscope out by invoking the f option This is useful for keeping separate symbol cross reference files in the same directory You may want to do this if two programs are in the same directory but do not share all the same files cscope f admin ref admin c common c aux c libs c cscope f delta ref delta c common c aux c libs c In this example the source files for two programs admin and delta are in the same directory but the programs consist of different groups of files By specifying different symbol cross reference files when you invoke cs
231. e lh at 16 32 QUES boone Ss Sod oho eee utet sg PME EE UE ee 16 33 Sem aphores i cec ete ea DR cede C Rs 16 33 Date and Time 9334 55 feed nb a is 16 33 General Date and Time ee eee ee 16 34 Interval Timet ci ee ee EU Le RE 16 35 POSIX TIMET ss 32443222 e ratos ato C d e 16 35 Internationalization lsseeeeeeeee I 16 35 Eocales Leid etre ee use e i aee ies 16 36 Contents Message Catalogs stone ss REIR De EORR IS na 16 36 Mathematic and Numeric n on nananana nnen eee 16 36 Trigsnomettric amp coeds e ey RR PT ee 16 37 Bessel as IC PLC Da 16 37 Fy pero is ceresc ert hes x oh aod a De SER RSS 16 38 Miscellaneous Mathematic Functions 000 c cece eee eee 16 38 Numeric Conversion resns reee aana e cece een ran 16 39 Other Arithmetic nananana eannan eee nee ne eens 16 41 Floating Point Environment 00 0 rreren rrer 16 41 Pseudo Random Number Generation Functions 0055 16 42 Programs a S GER ER HEN RC ed OR hehe 16 44 POWs tec st Sos er totes ae ON tba ee aah od ete etaed 16 44 Profile a dde SAT ce pe DERE 16 44 AS ee etd e Lea Aafia Sec edd tacos lege E 16 45 wie 025 5 P OE E RS LS EOS A EE E 16 45 Control a e ipl E 16 46 Sign ls bck cy ee nn 16 47 User Level Interrupts 0 0 cee eee ee eee 16 49 Lightweight Processes 0 0 cece eee eee eee 16 49 SECHEI Ya a i Tuc edades detiene ett Ced etta eet 16 50 Access Control Lists i erette ee hU Te REST
232. e nearest label 3 seen prior to the instruction and 8 f refers to the nearest label 8 seen after the instruction For example 6 cmpwi erf1 23 13 addi LS ES pl bgt 6r 1 6 cmpwi crf1 r3 4 blt crf 6b 6 NOTE The symbol Of may not be used as a numeric label because Of denotes the floating point constant 0 0 A line with in column is regarded as a comment line C style comments beginning with and ending with may appear anywhere in the source These comments may traverse multiple lines Comments to the end of the line may also be used The delimiter for this kind of comment is This delimiter can be used anywhere on the line Identifiers consist of the following characters a z A Z 0 9 o or and Compilation Systems Volume 1 Tools Identifiers must not begin with a digit If the assembler A option is used identifiers may also contain double quoted strings of the preceding character set and the characters lt gt and s The assembler does not prefix or suffix additional underscores to the identifier as some compilers do If a version 03 00 ora version 02 00 directive discussed ELF Symbol Attributes on page 2 17 does not exist in the assembly file the assembler removes a leading underscore if one exists from identifiers If a version 03 00 or aversion 02 00 directive does exist in the assembly file the assembler does not remove a leading underscore fro
233. ead Because you get our definitions of both read and read when you use fread we would expect the link editor to report the multiply defined symbol read as an error and fail to create an executable program To prevent that we used the pragma directive in our source code for the library as follows pragma weak read read Because our read is defined as a weak symbol your own definition of read will override the definition in the standard C library You can use the pragma directive in the same way in your own library code There s a second use for weak symbols that you ought to know about pragma weak read tells the link editor not to complain if it does not find a definition for the weak symbol read References to the symbol use the symbol value if defined 0 otherwise The link editor does not extract archive members to resolve undefined weak symbols The mechanism is intended to be used primarily with functions Although it will work for most data objects it should not be used with uninitialized global data common symbols or with shared library data objects that are exported to executables The link editor 1d automatically and intelligently maps input sections from object files o files to output segments in executable files a out files The mapfile option to the 1d command allows you to change the default mapping provided by the link editor In particular the mapfile option allows you to
234. eaf delta That is it must be the most recently created delta on its branch or on the trunk of the SCCS file tree In Figure 14 3 only deltas 1 3 1 2 1 3 2 2 and 2 2 can be removed Only after they are removed can deltas 1 3 2 1 and 2 1 be removed To be allowed to remove a delta the effective user must have write permission in the directory containing the SCCS file In addition the real user must be either the one who created the delta being removed or the owner of the SCCS file and its directory The r key letter is mandatory with rmdel It is used to specify the complete SID of the delta to be removed Thus rmdel r2 3 s abc specifies the removal of trunk delta 2 3 Before removing the delta rmdel checks that the release number R of the given SID satisfies the relation floor is less than or equal to R which is less than or equal to ceiling floor and ceiling are flags in the SCCS file representing start and end of the range of valid releases The rmdel command also checks the SID to make sure it is not for a version on which a get for editing has been executed and whose associated delta has not yet been made In addition the login name or group ID of the user must appear in the file s user list or the user list must be empty Also the release specified cannot be locked against editing 14 23 Compilation Systems Volume 1 Tools That is if the 1 flag is set see admin 1 the release must not be contained in the
235. ece hh ener her 7 22 Hints for Preparing Specifications llle 7 23 Input Style nu res SS S RE TERR IA Padua 7 24 Eeft Recursioh sous ee ARN AI A IATA 7 24 Esxical Heister A re Na 7 25 Reserved Words 422 54 rennen 7 26 Advanced Topics 0 00 ia i cee ete eee a e 7 26 Simulating error and accept in Actions 22 0 0 0 0 e eee eee eee 7 26 Accessing Values in Enclosing Rules 0 00 00 eee ee eee 7 26 Support for Arbitrary Value Types lees 7 27 yacc Input Mai sn ne e dee 7 29 Examples na A RG Soe ee eee 7 30 1 A Simple Example re it 7 30 2 An Advanced Example o ooooooococccco eee eee 7 33 Compilation Systems Volume 1 Tools Part 2 Analysis Chapter 8 Introduction to Analysis Introduction o A meis St eT EG qu BES 8 1 Chapter 9 Browsing Through Your Code with cscope Introd ctiom io mex Re e ERI e ees ER IE eee 9 1 How escope Works roria saa ER AT ee ees Ea len 9 1 Howto Use Cscopes 55s ea ee Rr el tees ree Be 9 1 Step 1 Set Up the Environment sleeleleeee eA 9 2 Step 2 Invokecscope 2 2 cette teens 9 2 Step 3 Locate th Coders 2 en A ae LE FUSE ee ee 9 3 Step 4 Edit the Codeist 22H na SS Wa Reken 9 9 Command Line Options 2 0 0 0c eee ee 9 10 Using Viewpaths 0 0 0 ec Ie 9 13 Stacking cscope and Editor Calls 0 0 2 2 eee eee eee 9 14 EXAMpIES nn A ome ded e o at 9 14 Changing a Constant to a Preprocessor Symbol o ooo ooo
236. ecified on the command line in the VPATH macro specification as a colon separated list of directories to be searched The third method is to specify the VPATH macro within the makefile being used again as a blank or colon separated list of directories Finally the VPATH may be specified within the environment by setting the VPATH environment variable to a blank or colon separated list of directories In all cases the directories specified may be absolute paths or relative to the current working directory The methods have been identified in the order of precedence in other words the method of using v viewpath takes precedence over the others Examples of how to invoke use these methods are illustrated below To search for components in the current working directory and usr src mak f makefil v usr src To search for components in the current working directory mysrc and usr src in that order 13 15 Compilation Systems Volume 1 Tools mak f makefile VPATH mysrc usr src To search for components in the current working directory mysrc usr src and yoursrc in that order VPATH mysrc usr src DIR1 DIR1 yoursrc OBJS main o allocate o delete o outfile OBJS CC o OBJS main o main c allocate o allocate c delete o delete c With this enhancement SCCS directories can now be searched for build components sim ply by specifying the SCCS directory in one of the above methods This enha
237. ect A consumer of this information such as a debugger would need to dynamically add the addressing base to this difference to determine the actual address of the symbol The local directives are needed to indicate that the symbols are to be regarded as inaccessible from other files and shared objects 3 PowerPC Instruction Set Summary PowerPC Instruction Set oe ecese tesi dee a a ae cena 3 2 Condition Codes iee uo e eR ashes eec eere ea 3 25 Trap Operand 2 2 08 LR DIRE Sad EE Dee ers wee Dee 3 26 Operand Abbreviations ser ia exu eo aeg 3 26 Special Purpose Registers lese e 3 28 Time Base Registers vibe Ree e e eoe eie ee idt ee 3 31 Implementation Specific and Optional Instructions 004 3 31 Compilation Systems Volume 1 Tools PowerPC Instruction Set Summary 3 PowerPC Instruction Set Summary This chapter summarizes the instruction sets of the PowerPC 601 602 603 603e 604 604e 620 and 75021 microprocessors Instructions specific to or excluded from other members of the PowerPC family are not documented here These processors are docu mented to assist porting between PowerPC implementations These tables are based on preliminary documentation from the chip manufacturers The information contained is subject to change without notice The following special notation conventions apply to tables in this chapter only In the PowerPC Mnemonic column Bold mnemonics Italic mnemonics
238. ed prof will be generated with the profiling statistics The C option adds statistics about cache misses due to instruction fetches and data accesses to the profile data With the C option the patched program simulates the activity of the primary instruction and data caches as well as that of the secondary cache This 11 3 Compilation Systems Volume I Tools Usage 11 4 option can be useful for diagnosing performance problems arising from lack of memory access locality proximity It should be used with care because it can significantly increase run time overhead and the size of the executable program Currently the statistics are only as accurate as the timing information shown in the disassembly listing Both min and max times are accumulated so the report can print only upper and lower bounds on the cycle count A future version may attempt to add code that will correct the cycle count with additional information gathered about pipe conflicts that will occur depending on the arc followed to reach each basic block It is often difficult to profile some programs especially those generated by non Concur rent compilers The following guidelines are given as an aid to people attempting to profile foreign code The analyze tool relies on the symbol table to find subroutine entry points A stripped program cannot be profiled Even if a symbol table exists analyze can identify subroutine entry points only if they have associated t
239. eference of interest you can invoke cscope again from within the editor to view the second reference without exiting the current invocation of either cscope or the editor You can then back up by exiting the most recent invocation with the appropriate cscope and editor commands Examples This section presents examples of how cscope can be used to perform three tasks chang ing a constant to a preprocessor symbol adding an argument to a function and changing the value of a variable The first example demonstrates the procedure for changing a text string which differs slightly from the other tasks on the cscope menu Once you have entered the text string to be changed cscope prompts you for the new text displays the lines containing the old text and waits for you to specify which of these lines you want it to change Changing a Constant to a Preprocessor Symbol Suppose you want to change a constant 100 to a preprocessor symbol MAXSIZI Select the sixth menu item Change this text string and enter 100 The 1 must be escaped with a backslash because it has a special meaning item 1 on the menu to cscope Press RETURN cscope will prompt you for the new text string Type MAXSIZE Ei cscope Press the key for help Pam CRL OC es ymborli Find this global definition Find functions called by this function Find functions calling this function Find this tezt string Change this text string Find this egrep pattern
240. efined in shared objects to be copied into the memory image of the executable by the dynamic linker at run time With the b option the output code may be more efficient but it will be less sharable When dy the default if STATIC LINK is not set is specified use dynamic linking when dn is specified use static linking Set the default entry point address for the output file to be that of the symbol epsym In dynamic mode only when building a shared object record name in the object s dynamic section name will be recorded in executables that are linked with this object rather than the object s system file name Accordingly name will be used by the dynamic linker as the name of the shared object to search for at run time Search a library libx so or libx a libx so and libx a are the conventional names for shared object and archive libraries respectively In dynamic mode unless the Bstatic option is in effect 1d searches each directory specified in the library search path for a file libx so or libx a The directory search stops at the first directory containing either 1d chooses the file ending in so if 1x expands to two files whose names are of the form libx so and libx a If no libx so is found then 1d accepts libx a In static mode or when the Bstatic option is in effect 1d selects only the file ending in a A library is searched when its name is encountered so the placement of 1 is significant By defau
241. efore issuing any command certain internally maintained macros are set The macro is set to the full target name of the current target The macro is evaluated only for explicitly named dependencies The macro is set to the string of names that were found to be younger than the target The macro is evaluated when explicit rules from the makefile are evaluated If the command was generated by an implicit rule the lt macro is the name of the related file that caused the action and the macro is the prefix shared by the current and the dependent file names If a file must be made but there are no explicit commands or relevant built in rules the commands associated with the name DEFAULT are used If there is no such name make prints a message and stops In addition a description file may also use the following related macros QD S F S D S F lt D and lt F see below 13 7 Compilation Systems Volume 1 Tools Extensions of and lt The internally generated macros Q and lt are useful generic terms for current targets and out of date relatives To this list is added the following related macros S D F D S F lt D and F The D refers to the directory part of the single character macro The F refers to the file name part of the single character macro These additions are useful when building hierarchical makefiles They allow access to directory names for purposes o
242. either to regenerate a g file that may have been accidentally removed or ruined after get e or simply to generate a g file in which the replacement of ID key words has been suppressed A g file generated by get k is identical to one produced by get e but no processing related to p file takes place Concurrent Edits of Different SID The ability to retrieve different versions of an SCCS file allows several deltas to be in progress at any given time This means that several get e commands may be executed on the same file as long as no two executions retrieve the same version unless multiple concurrent edits are allowed The p file created by get e is created in the same directory as the SCCS file given mode 644 readable by everyone writable only by the owner and owned by the effective user It contains the following information for each delta that is still in progress 14 13 Compilation Systems Volume 1 Tools The SID of the retrieved version The SID given to the new delta when it is created The login name of the real user executing get The first execution of get e causes the creation of p file for the corresponding SCCS file Subsequent executions only update p file with a line containing the above information Before updating however get checks to assure that no entry already in p file specifies that the SID of the version to be retrieved is already retrieved unless multiple concurrent edits are allowed If
243. el o Define two macros 8 projlib and pfilel 7 Look for a rule X a and a file X The first X in the SUFFIXES list which fulfills these conditions is c so the rule is c a and the file is pfilel c Set lt to be pfilel c and execute the rule In fact make must then compile pfilel c 8 The library has been updated Execute the command associated with the projlib dependency namely echo projlib up to date It should be noted that to let pfilel o have dependencies the following syntax is required projlib pfilel o S INCDIR stdio h pfilel c There is also a macro for referencing the archive member name when this form is used The macro is evaluated each time SQ is evaluated If there is no current archive member is null If an archive member exists then evaluates to the expression between the parenthesis 13 12 Managing File Interactions with make Source Code Control System File Names The Null Suffix The syntax of make does not directly permit referencing of prefixes For most types of files on UNIX operating system machines this is acceptable since nearly everyone uses a suffix to distinguish different types of files SCCS files are the exception Here s precedes the file name part of the complete path name To allow make easy access to the prefix s the symbol is used as an identifier of SCCS files Hence c o refers to the rule which transforms an SCCS C language source file into
244. em at link time That will save memory because only the processes that need the buffers will get them It will also allow the size of the buffers to change from one release of the library to the next without affecting compatibility Example char buffer static char buf 0 if buf 0 if buf malloc BUFSIZE 0 return 0 return buf Exclude functions that use large amounts of global data that is if you cannot rewrite them in the ways described in the foregoing items If an infrequently used routine defines a great deal of static data it probably does not belong in a shared library Make the library self contained If a shared object imports definitions from another shared object each process that uses it will get a private copy not only of its data segment but of the data segment of the shared object from which the definitions were imported In cases of conflict this guideline should probably take precedence over the preceding one Minimize Paging Activity Although processes that use shared libraries will not write to shared pages they still may incur page faults To the extent they do their performance will degrade You can minimize paging activity in the following ways Organize to improve locality of reference First exclude infrequently used routines on which the library itself does not depend Traditional a out files contain all the code they need at run time So if a process calls a fu
245. en you execute your program Whereas the dynamic linker resolves data references immediately at run time it normally delays resolving function references until a function is invoked for the first time Normally then the lack of a definition for a function will not be apparent until the function is invoked By setting the environment variable LD_BIND_NOW Link Editor and Linking LD_BIND_NOW 1 export LD_BIND_NOW before you execute your program you direct the dynamic linker to resolve all references immediately In that way you can learn before execution of main begins that the functions invoked by your process actually are defined Dynamic Linking Programming Interface You can use a programming interface to the dynamic linking mechanism to attach a shared object to the address space of your process during execution look up the address of a function in the library call that function and then detach the library when it is no longer needed The routines for this are stored in 1ibdl so Subsection 3X man pages describe its contents Implementation We have already described in various contexts in this section the basic implementation of the static and dynamic linking mechanisms When you use an archive library function a copy of the object file that contains the function is incorporated in your executable at link time External references to the function are assigned virtual addresses when the executable is created When you
246. ent Computer Corporation s compilation systems provide all of the facilities described above except for interpreters The compilers produce assembly language files These are assembled into relocatable object files and the relocatable object files are combined into an executable program Concurrent Computer Corporation s compilers share a common back end which is responsible for optimization and code generation This Common Code Generator CCG technology makes it possible to easily add support for new languages and to retarget existing compilers to new hardware platforms Concurrent Computer Corporation has developed its own compilers They are not reincarnations of compilers produced by other vendors Table 1 1 shows which compilers and utilities are available 1 3 Compilation Systems Volume 1 Tools 1 4 Table 1 1 Compilers and Utilities Type Name Description C compiler cc 1 Both ANSIC and old style C are accepted as are Concurrent Com puter Corporation extensions to the C language Fortran 77 1 The ANSI Fortran 77 language is accepted as are Concurrent Com compiler puter Corporation extensions to the Fortran language Ada compiler ada 1 Concurrent Computer Corporation provides a complete Ada programming support environment known as HAPSE C cpp 1 The C preprocessor expands macros and performs other preprocessors acpp 1 preprocessing functions on the source code as part of the compilat
247. ent value of the location counter Its recommended use is to set the location counter at a known offset beyond an already seen label The directive should be in the same section as the referenced label A constant counter may be used but the assembler will produce a warning message For example label long 5 org label 30 change the location counter to 30 past the label zero space number number bytes of zeroes 10 are assembled at the current location counter number must be non negative It is of manifest type For example zero 24 assemble 24 bytes of zeroes 2 12 Assembler and Assembly Language Section Switching text text The location counter is changed to the next available value in the text section Before the first section directive is encountered in an input file assembly is by default directed into the text section data data The location counter is changed to the next available value in the data section section identifier attributes sectiontype Succeeding bytes are assembled into the section named identifier One or more flags comprise a quoted character string of attributes for the section The attributes flags are optional The attributes are indicated in the sh 1ags entry of the section header The assembler permits another optional parameter sectiontype which is indicated in the sh t ype entry in the section header This section is created if it does not already
248. er static linking copies of the archive library object files that satisfy still unresolved external references in your program are incorporated in your executable at link time External references in your program are connected with their definitions assigned addresses in memory when the executable is created Under dynamic linking the contents of a shared object are mapped into the virtual address space of your process at run time External references in Link Editor and Linking your program are connected with their definitions when the program is executed In this section we ll examine the link editing process in detail We ll start with the default arrangement and with the basics of linking your program with the standard libraries supplied by the C compilation system Later we ll discuss the implementation of the dynamic linking mechanism and look at some coding guidelines and maintenance tips for shared library development Throughout the discussion we ll consider the reasons why you might prefer dynamic to static linking These are briefly Dynamically linked programs save disk storage and system process mem ory by sharing library code at run time Dynamically linked code can be fixed or enhanced without having to relink applications that depend on it Default Arrangement We stated earlier that the default cc command line cc filel c file2 c file3 c would create object files corresponding to each of your source files
249. erms 603 604 620 and 640 are used similarly Escala is a trademark of Bull Information Systems IBM RS 6000 PowerPC PowerPC 601 PowerPC 603 PowerPC 604 PowerPC 620 POWER and POWER are trademarks of International Business Machines Corporation PowerUX is a trademark of Concurrent Computer Corporation PowerMAX OS is a trademark of Concurrent Computer Corporation UNIX is a registered trademark of the Open Group Other products mentioned in this document are trademarks registered trademarks or trade names of the manufacturers or marketers of the products with which the marks or names are associated Printed in U S A Revision History Level Effective With Original Release October 1994 000 PowerUX 1 0 Previous Release March 1997 040 PowerMAX OS 4 1 Current Release April 1999 050 PowerMAX OS 4 3 Scope of Manuals Preface The Compilation Systems Manual set is composed of two manuals Compilation Systems Volume I Tools and Compilation Systems Volume 2 Concepts The Compilation Systems Volume I Tools manual describes the features and use of several software development environment tools analysis tools and project control tools The Compilation Systems Volume 2 Concepts manual describes the concepts behind compilation systems including environments performance analysis and formats Information in this manual applies to the PowerPC platforms described in the Concurrent Computer Corporation Product Cata
250. es 13 2 The basic operation of make is to update a target file by ensuring that all of the files on which the target file depends exist and are up to date The target file is regenerated if it has not been modified since the dependents were modified The make program builds and searches a graph of these dependencies The operation of make depends on its ability to find the date and time that a file was last modified The make program operates using three sources of information A user supplied description file File names and last modified times from the file system Builtin rules supply default dependency information and implied commands To illustrate consider a simple example in which a program named prog is made by compiling and loading three C language files x c y c and z c with the math library libm By convention the output of the C language compilations will be found in files named x o y o and z o Assume that the files x c and y c share some declarations in a file named defs h but that z c does not That is x c and y c have the line finclude defs h The following specification describes the relationships and operations prog x o y o Zz O CC X O y o Z o lm o prog Ke Wa oz defs h If this information were stored in a file named makefile the command make would perform the operations needed to regenerate prog after any changes had been made to any of the four source files x c y c z c or de s
251. es maintaining 13 11 13 12 Archiver 1 3 1 4 Arithmetic functions 16 41 as invocation 2 2 as 1 1 4 Assembler 1 2 1 4 Assembler directive 2 6 Assembly language 1 2 2 1 2 2 2 4 2 5 2 6 2 8 2 9 2 10 2 11 2 12 2 15 2 17 2 19 2 20 2 21 Alphanumeric labels 2 4 Assembler directives 2 12 2 17 2 19 Assembler invocation 2 2 Assembly syntax 2 21 Character constants 2 9 Character set 2 4 Index 1 Compilation Systems Volume 1 Tools Constants 2 8 2 9 Directives mnemonics 2 19 Expression operators 2 10 Expression types 2 10 2 11 Expression values 2 11 Expressions 2 9 2 10 2 11 Floating point constants 2 8 Identifiers 2 6 2 8 identifiers 2 5 Integer constants 2 8 Location counter control 2 12 Null statements 2 4 Numeric local labels 2 5 Operator precedence 2 10 Position independent code 2 21 Predefined symbols 2 5 2 6 Source statements 2 4 2 5 Symbol attributes 2 17 User defined symbols 2 8 Using the assembler 2 2 2 20 Assembly language Comments Comments 2 5 Auditing functions 16 51 Back end 1 3 Backward reference 2 5 base address 22 38 Bessel Functions 16 37 Bessel functions 16 37 Binary tree functions 16 32 Binary Tree Management 16 32 bit fields 10 4 Branch displacement optimization 2 20 Branch optimizations 20 10 20 11 20 12 Browser C 1 5 bss directive 2 17 byte directive 2 14 C C code browser 1 5 C code checkter 1 5 C compiler 1 4 C library 16 1 16 2 linking with 4 9 4 11 C pre
252. es and executable programs are two kinds of object files Compilation Systems Volume 1 Tools Stack Frames An object file must have a well defined format if it is to be used by the various utilities in a compilation system The object file format used under PowerUX is the Executable and Linking Format ELF This format provides object file sections which contain the various components of an object file such as the machine level instructions relocation information and the symbol table It also specifies the segments an executing program will have in the address space Information about an object file that can be used by a symbolic debugger is often embedded within the object file ELF was designed to be independent of any particular representation of symbolic debugging information Thus Debugging With Arbitrary Record Format DWARF has become the de facto representation for use with ELF and it is used under PowerUX During execution a computer program utilizes a portion of its address space known as the stack Each subroutine or procedure that is currently active utilizes a contiguous group of words on the stack which is that subroutine s stack frame The stack frame contains such information as the address to which the subroutine should return when it completes its execution the address of the stack frame corresponding to the subroutine which invoked the current subroutine the values of certain registers upon entry to the current su
253. es and or data that are provided by another relocatable object file The link editor resolves these references Sometimes it is useful to maintain a library of relocatable object files A programmer could then include object files from the library with object files that are specific to the program This library of relocatable object files is also referred to as an archive and the archive is maintained by an archiver When utilizing an archive the link editor incorporates into the program only those relocatable object files which are needed by the program The system on which a program is developed provides several system libraries Newly written programs seldom execute correctly on the first run requiring the programmer to debug the program A debugger utility is often used to facilitate the search for problems in the code Some debuggers operate only at the level of machine instructions Symbolic debuggers permit debugging at the source code level Once a program is running correctly it is sometimes desirable to analyze its performance and identify bottlenecks during its execution Profiling tools are called upon to perform this analysis These tools are available in various degrees of complexity Finally compilation systems provide a set of tools for examining compressing and performing miscellaneous functions on source code relocatable object files and execut able programs Concurrent Computer Corporation Compilation Systems Concurr
254. f Subprograms Ada only 0000 0000005 20 26 Optimization of Constraints Ada only eese 20 27 Inline Expansion of Subprograms C only 000000000 20 29 Precise Alias Analysis C Only 0 0 0 0 cee eee eee eee 20 30 Programming Techniques 0 0 cece cee teens 20 30 Coding TIPS 2 D er ED ee rs ee wi 20 31 Identifying Performance Problems 0 0 0 0 eee eee 20 32 Debugging Optimized Code 0 0 0 cee eee eee 20 32 Understanding Optimization s Effects on Debugging 20 33 Examining Your Program 1 0 0 eee eects 20 34 Part6 Formats Chapter 21 Introduction to Formats Introduction sya A AAA AT 21 1 Chapter 22 Executable and Linking Format ELF ThtrOdUCHON it A AE 22 1 Flle Formats da e eS ee pena a BA E O ch ech 22 1 Data Reptesentation c suene ao o er a ae a niet 22 2 Program Linking 2 cnet ernennen 22 3 ERF Headet ears nn HE RL 22 3 ELF Identifieation ar a ne ee a Da Ben 22 6 ELF Header Flags 222 0 Resale oa ae ah 22 9 Section Header wc au ne esee teret ep ede PB 22 9 Special Sections m nn Sothys ea AA ow Bes ERR ee Ree 22 15 Vendor Secon Li be rs A 22 18 String Table aire ni EEUU 22 22 Symbol Table ace tee euer etes ib ete da 22 23 Symbol Values ucc usa BR Te UY 22 26 Relocations cities Cant tet DR IS IRE Pose ERN LIS 22 21 Relocation Typeszc cese eae RUSO Ga eet Re Y ee cde he enr RE 22 28 Program E
255. f using the cd command of the shell Thus a command can be cd lt D S MAKE lt F Output Translations The values of macros are replaced when evaluated The general form where brackets indicate that the enclosed sequence is optional is as follows macro string17 string2 The parentheses are optional if there is no substitution specification and the macro name is a single character If a substitution sequence is present the value of the macro is considered to be a sequence of words separated by sequences of blanks tabs and new line characters Then for each such word that ends with string string is replaced with string2 or no characters if string2 is not present This particular substitution capability was chosen because make usually concerns itself with suffixes The usefulness of this type of translation occurs when maintaining archive libraries Now all that is necessary is to accumulate the out of date members and write a shell script that can handle all the C language programs that is files ending in c Thus the following fragment optimizes the executions of make for maintaining an archive library S LIB LIB a o LIB b o LIB c o S CC c S CFLAGS o c S AR S ARFLAGS LIB rm A dependency of the preceding form is necessary for each of the different types of source files suffixes that define the archive library These translations are added in an effort to
256. fault action represented by is often a reduce action reduce actions are associated with individual grammar rules Grammar rules are also given small integer numbers and this leads to some confusion The action reduce 18 refers to grammar rule 18 while the action IF shift 34 refers to state 34 Suppose the rule 7 9 Compilation Systems Volume I Tools 7 10 Poe Ge RS DY WV 7v is being reduced The reduce action depends on the left hand symbol A in this case and the number of symbols on the right hand side three in this case To reduce first pop off the top three states from the stack In general the number of states popped equals the number of symbols on the right side of the rule In effect these states were the ones put on the stack while recognizing x y and z and no longer serve any useful purpose After popping these states a state is uncovered which was the state the parser was in before beginning to process the rule Using this uncovered state and the symbol on the left side of the rule perform what is in effect a shift of A A new state is obtained pushed onto the stack and parsing continues There are significant differences between the processing of the left hand symbol and an ordinary shift of a token however so this action is called a goto action In particular the lookahead token is cleared by a shift but is not affected by a goto In any case the uncovered state contains an entry such as A goto 20
257. file This is useful when the list would be too long for the 1d invocation line Qmult archive Perform multiple passes over the list of archive libraries to satisfy unresolved symbol references Each pass examines the archive libraries in the order in which they appear on the invocation line Without this option only one pass is made over the list of archive libraries Qno vendor reloc Do not output relocation information in the vendor section of the object file for use by the analyze 1 tool By default this relocation information is output This option cannot be used with the O option Onotdesc Suppress the production of tdesc information Qsearch order When performing multiple passes over the list of archive libraries to satisfy unresolved symbol references do not search for unresolved references detected in the current pass until the next pass This option implies the Qmult_archive option Qsmall memory By default the link editor allocates the data space of the program beginning at address segment 3 allowing programs to use up to several address segments of memory for their data space With 4 6 Link Editor and Linking this option the link editor allocates the data space only in address segment 2 Ostandard_fortran_common By default the link editor checks for and properly handles certain nonstandard Fortran common block constructs but at the expense of increased link time Use of this option reduces link time
258. filel c file2 c You can specify I more than once on the lint command line Directories are searched in the order they appear on the command line Of course you can specify multiple options to lint on the same command line Options may be concatenated unless one of the options takes an argument lint cp Idir Idir filel c file2 c That command directs Lint to Execute the first pass only Perform additional portability checks Search the specified directories for included header files You can use lint libraries to check your program for compatibility with the library functions you have called in it the declaration of the function return type the number and types of arguments the function expects and so on The standard lint libraries correspond to libraries supplied by the C compilation system and generally are stored in the standard place on your system the directory usr ccs 1ib By convention lint libraries have names of the form 11ib 1x 1n The lint standard C library 1lib 1c 1n is appended to the Lint command line by default checks for compatibility with it can be suppressed by invoking the n option Other lint libraries are accessed as arguments to 1 lint lx filel c file2 c directs Lint to check the usage of functions and variables in filel cand file2 c for compatibility with the Lint library 11ib 1x 1n The library file which consists only of definitions is processed exactly as are ordinary source file
259. form other tasks as well Finally you can create your own shared objects and archive libraries We ll show you the mechanics of doing that below The default arrangement then is this the ec command creates and then links relocatable object files to generate an executable program then arranges for the executable to be linked with the shared C library at run time If you are satisfied with this arrangement you need make no other provision for link editing on the cc command line Linking with Standard Libraries 4 10 libc so is a single object file that contains the code for every function in the shared C library When you call a function in that library and dynamically link your program with it the entire contents of libc so are mapped into the virtual address space of your process at run time Archive libraries are configured differently Each function or small group of related functions typically the related functions that you will sometimes find on the same manual page is stored in its own object file These object files are then collected in archives that are searched by the link editor when you specify the necessary options on the cc command line The link editor makes available to your program only the object files in these archives that contain a function you have called in your program You create a shared object library by specifying the Zlink so option to the compiler As noted libc a is the archive version of the standard
260. g Point Formats to Integer llle esee 17 11 Sq are Roots asien ee er ner dede ce eto teen 17 12 Compares and Unordered Condition 0 00 00 e eese 17 12 XV Compilation Systems Volume 1 Tools NaNs and Infinities in Input Output 0 00 00 0 eee eee 17 12 Chapter 18 Inter Language Interfacing Introduction A Ree len e 18 1 Subroutine Linkage irea i eea n a p ia nennen 18 1 TheStack Frame sssr oe a un an A Ses 18 1 Barameters AR seed tte cede tt cet e ge Ad AN A s 18 2 Return Values 5 A eb E reete 18 3 Prologue and Epilogue lslseeseseeee ee 18 3 Register Usage omiso Hoch ee at Sd REM we ee 18 4 External NAMES 42 22 d coi tO x feta ta tease Bea aca Ar ce 18 5 Data TY iS dacs re SE E 18 5 Scalar Types 4 duced te ee de eei pecie a she vase oc 18 5 Stnictures e E cs e EE a A ER ee As RUBER RSEN 18 6 Common Blocks 0 0c eh ha 18 6 Part5 Program Optimization Chapter 19 Introduction to Program Optimization Introduction i A GG REESE IE en 19 1 Chapter 20 Program Optimization Introduction to Compiler Technology 0 0 esee eese 20 1 Compiler Optimization Options llle 20 2 Setting the Compiler Optimization Level 00 00 0005 20 2 Controlling Compiler Optimizations 0 0 0 0 eee eee 20 3 Giving Hints to Compiler Optimizations C only 04 20 8 Obtaining Optimization Messages isses 20 1
261. g the input to find further syntax errors This leads to the problem of getting the parser restarted after an error A general class of algorithms to do this involves discarding a number of tokens from the input string and attempting to adjust the parser so that input can continue To allow the user some control over this process yace provides the token name error This name can be used in grammar rules In effect it suggests where errors are expected and recovery might take place The parser pops its stack until it enters a state where the token error is valid It then behaves as if the token error were the current lookahead token and performs the action encountered The lookahead token is then reset to the token that caused the error If no special error rules have been specified the processing halts when an error is detected Parsing with yacc In order to prevent a cascade of error messages the parser after detecting an error remains in error state until three tokens have been successfully read and shifted If an error is detected when the parser is already in error state no message is given and the input token is quietly deleted As an example a rule of the form stat error means that on a syntax error the parser attempts to skip over the statement in which the error is seen More precisely the parser scans ahead looking for three tokens that might validly follow a statement and starts processing at the first of these If the beg
262. get s lang retrieves the latest version of the file s lang now 1 2 SCCS does this by starting with the original version of the file and applying the delta you made If you use the get command now any of the following will retrieve version 1 2 get s lang get r1 s lang get r1 2 s lang The numbers following r are SIDs When you omit the level number of the SID as in get r1 s lang the default is the highest level number that exists within the specified release Thus the second command requests the retrieval of the latest version in release 1 namely 1 2 The third command requests the retrieval of a particular version in this case also 1 2 Whenever a major change is made to a file you may want to signify it by changing the release number the first number of the SID This too is done with the get command get e r2 s lang Because release 2 does not exist get retrieves the latest version before release 2 get also interprets this as a request to change the release number of the new delta to 2 thereby naming it 2 1 rather than 1 3 The output is 152 new delta 2 1 7 lines which means version 1 2 has been retrieved and 2 1 is the version the delta command will create If the file is now edited for example by deleting COBOL from the list of languages and delta is executed delta s lang comments deleted cobol from list of languages you will see by delta s output that version 2 1 is indeed created Des ll
263. gotp peplt s rel sQgot rel pQgotp rel peplt_rel sQabdiff The address of a global offset table entry for symbol s The address of a global offset table procedure entry for the procedure named by the symbol p An address to which control can be transferred to invoke the procedure named by symbol p It is either the address of p or the address of a procedure linkage table entry for p The difference between the value of the symbol s and the addressing base for the object containing the expression The value of the symbol s must represent an address in the object containing the expression The difference between the address denoted by s got and the addressing base for the object containing the expression The difference between the address denoted by p gotp and the addressing base for the object containing the expression The difference between the address denoted by p plt and the addressing base for the object containing the expression The difference between the addressing base for the shared object containing the expression and the value of the symbol s The value of the symbol s must represent an address in the object containing the expression The addressing base refers to a particular virtual address associated with the memory image of a shared object A position independent function establishes the addressing base by computing its value and preserving it in a register for use through out the activation of the function T
264. h may have some value as a guide It is computed by multiplying the max time for each basic block by a weighting factor that increases rapidly as the loop nesting level goes up The accumulated time for all the blocks is the BURT number ERNIE ERNIE is External Routine Necessary Interface Executions and is a statistic designed to help you decide if BURT numbers are different because subroutines have been inlined or vice versa or if they are different simply because of different code quality ERNIE is computed by simply adding up all the nesting level factors for any block that contains a subroutine call The above statistics all depend on accurately computing loop nesting levels If the flow graph is irreducible then it is difficult to decide just what a loop is so a warning is generated for routines with irreducible flow graphs Often when code finally gets generated a single basic block will be the header of several back edges Each back edge is counted as a separate loop so the nesting level for the header may get very high The P option patches the input program generating a new program which will accumulate cycle count statistics at the basic block level and dump them to an output file on exit The statistics are always dumped to a file with the same name as the executable given as the argument to P with the prof suffix added For example if you specified Pfred then when you run the generated program the file fr
265. have to use lex to handle problems of this kind You could write programs in a standard language like C to handle them too In fact what lex does is produce such C programs lex is therefore called a program generator What lex offers you once you acquire a facility with it is typically a faster easier way to create programs that perform these tasks Its weakness is that it often produces C programs that are longer than necessary for the task at hand and that execute more slowly than they otherwise might In many applications this is a minor consideration and the advantages of using lex considerably outweigh it lex can also be used to collect statistical data on features of an input text such as character count word length number of occurrences of a word and so forth In the remaining sections of this chapter we will see How to generate a lexical analyzer program How to write lex source How to translate source How to use lex with yacc Generating a Lexical Analyzer Program lex generates a C language scanner from a source specification that you write to solve the problem at hand This specification consists of a list of rules indicating sequences of characters expressions to be searched for in an input text and the actions to take when an expression is found We ll show you how to write a lex specification in Writing lex Source on page 6 3 The C source code for the lexical analyzer is generated when you enter
266. he word first on every line that begins with the letter a change magic to second on every line that begins with b change magic to third on every line that begins with c Here is how the problem might be handled with a flag Recall that ECHO is a lex macro equivalent to printf Ss yytext Val EEC HO ECHO cu RECO OF FECHO ZP switch flag printr ams praak case Voss printt second break case a CASCOS default ECHO break To handle the same problem with start conditions each start condition must be introduced to lex in the definitions section with a line reading Start namel name2 where the conditions may be named in any order The word Start may be abbreviated to S or s The conditions are referenced at the head of a rule with lt gt brackets So lt name1 gt expression 6 13 Compilation Systems Volume I Tools User Routines 6 14 is a rule that is only recognized when the scanner is in start condition namel To enter a start condition execute the action statement BEGIN namel which changes the start condition to namel To resume the normal state BEGIN 0 resets the initial condition of the scanner A rule may be active in several start conditions That is namel name2 name3 gt is a valid prefix Any rule not beginning with the lt gt prefix operators is always active The example can be written with start conditions as follows Start AA BB CC BEGIN
267. he following C code serves to illustrate the difference between position independent and position dependent code at the assembly language level Assembly source that is accepted by the assembler is used in this example int global int global ptr sub extern char malloc global_ptr int malloc 20 global_ptr global Assembler and Assembly Language Position Independent Position Dependent sub base be en global sub addi r1 r1 80 stw r16 64 r1 mflr r13 stw r13 88 r1 local base bl base ori r16 r16 1016 base abdiff mflr r13 add r16 r16 r3 local be lis r3 uhil6 malloc gotp_rel ori 13 73 lol6 malloc 9 gotp_rel lwzx 14 r16 13 li r3 1016 0x14 mtetr r4 btcrl lis r4 uhil6 global_ptr got rel ori 14 14 lo16 global_ptr got_rel lwzx r4 r16 r4 stw 13 0 14 lis r3 uhil6 global got rel ori 13 13 lo16 global O got rel lwzx 13 r16 13 lwz 14 0 13 lis 13 uhi16 global_ptrO got_rel ori 13 13 1016 global_ptrO got_rel lwzx 13 r16 13 lwz 13 0 13 stw r4 0 r3 lwz r16 64 r1 lwz 113 88 r1 mtlr r13 addi r1 r1 80 blr sub be en global addi mflr stw bl lis stw lis lwz stw lwz mtlr addi blr sub r1 r1 80 r13 r13 88 r1 13 1016 0x 14 malloc r4 hil6 global ptr r3 lol6 global ptr r4 r4 hil6 global r4 1016 gloabl r4 r4 0 r3 r13 88 r1 r13 r1 r1 80 2 23 Compilation Systems Vo
268. he notion of precedence levels for operators together with information about left or right associativity It turns out that ambiguous grammars with appropriate disambiguating rules can be used to create parsers that are faster and easier to write than parsers constructed from unambiguous grammars The basic notion is to write grammar rules of the form expr expr OP exprand and expr UNARY expr for all binary and unary operators desired This creates a very ambiguous grammar with many parsing conflicts You specify as disambiguating rules the precedence or binding strength of all the operators and the associativity of the binary operators This information is sufficient to allow yacc to resolve the parsing conflicts in accordance with these rules and construct a parser that realizes the desired precedences and associativities The precedences and associativities are attached to tokens in the declarations section This is done by a series of lines beginning with the yace keywords left right or nonassoc followed by a list of tokens All of the tokens on the same line are assumed to have the same precedence level and associativity the lines are listed in order of increasing precedence or binding strength Thus left sleft Tek ja describes the precedence and associativity of the four arithmetic operators and are left associative and have lower precedence than and which are also left associative The keyword right is used
269. he program The presence of DT_BIND_NOW takes precedence over a directive to use lazy binding for this object when specified through the environment or via dlopen B dynamic static Options governing library inclusion Bdynamic is valid in dynamic mode only These options may be specified any number of times on the command line as toggles ifthe Bstatic option is given no shared objects will be accepted until Bdynamic is seen See also the 1 option Compilation Systems Volume 1 Tools Bexport list filename Bhide list filename Bsortbss list is comma separated sequence of symbol names filename contains a list of symbol names one symbol name per line Lines beginning with a character and blank lines are ignored Normally when building a shared object 1d makes all global and weak names defined in the shared object visible outside the object itself exported When building an executable it makes visible only those names used by the shared objects with which the executable is linked All other names are hidden This behavior can be modified with Bhide and Bexport When building a shared object Bexport is the default All global and weak definitions are exported Bexport with a set of symbol names instructs 1d to hide all global and weak definitions except those in the specified set CBhide means to hide all global and weak definitions Bhide with a set of symbol names means to export all global
270. he way for identically named libraries of either type If you have different versions of libfoo a in your directories the link editor will search the first one it finds A better alternative might be to leave 1ibfoo a where you had it in the first place and use the Zlibs static and Zlibs dynamic options to turn dynamic linking off and on The following command will link your program statically with 1ibfoo a and dynamically with libc so cc L home mylibs filel c file2 c file3 c Zlibs static lfoo Zlibs dynamic When you specify Qstatic the link editor will not accept a shared object as input until you specify Qdynamic In other words you can use these options as toggles any number of times on the cc command line cc L home mylibs filel c file2 c Zlibs static lfoo file3 c Zlibs dynamic lsharedob That command will direct the link editor to search First libfoo a to resolve still unresolved external references in filel cand file2 c e Second libsharedob so to resolve still unresolved external references in all three files and in libfoo a ast libc so to resolve still unresolved external references in all three files and the preceding libraries Files including libraries are searched for definitions in the order they are listed on the cc command line The standard C library is always searched last You can add to the list of directories to be searched by the link editor by using the environment variable L
271. here First because shared object code is not copied into your executable object file at link time a dynamically linked executable normally will use less disk space than a statically linked executable For the same reason shared object code can be changed without breaking executables that depend on it In other words even if the shared C library were enhanced in the future you would not have to relink programs that depended on it as long as the enhancements were compatible with your code see Checking for Run Time Compatibility on page 4 16 The dynamic linker would simply use the definitions in the new version of the library to resolve external references in your executables at run time Second we specified the name of the shared object that we wanted to be created under the Zlink so option Of course you don t have to do it the way we did The following command for example will create a shared object called a out cc Zlink so functionl o function2 0 function3 o You can then rename the shared object mv a out libfoo so As noted you use the 1ib prefix and the so suffix because they are conventions recognized by 1 just as are lib and a for archive libraries So while it is legitimate to create a shared object that does not follow the naming convention and to link it with your program cc Zlink so o sharedob functionl o function2 0 function3 o cc filel c file2 c file3 c path sharedob we recommend against it Not o
272. here the string s2 occurs 1 if it does not occur As with substr the origin for strings is 0 translit performs character transliteration and has the general form translit s f t which modifies s by replacing any character in f by the corresponding character in t Using input translit s aeiou 12345 replaces the vowels by the corresponding digits If t is shorter than f characters that do not have an entry in t are deleted As a limiting case if tis not present at all characters from f are deleted from s translit s aeiou would delete vowels from s The macro dnl deletes all characters that follow it up to and including the next new line It is useful mainly for throwing away empty lines that otherwise would clutter up m4 output Using input define N 100 define M 200 define L 300 results in a new line at the end of each line that is not part of the definition The new line is copied into the output where it may not be wanted When you add dn1 to each of these lines the new lines will disappear Another method of achieving the same result is to input divert 1 define divert The built in errprint writes its arguments out on the standard error file An example would be errprint fatal error dumpdef is a debugging aid that dumps the current names and definitions of items specified as arguments If no arguments are given then all current names and definitions are printed
273. i 1U 6 i unsigned 4 3 7 4 warning assignment of negative constant to unsigned assignment operator found where was expected Format Simple 10 14 Analyzing Your Code with lint An assignment operator was found where a conditional expression was expected The message is not issued when an assignment is made to a variable using the value of a function call or in the case of string copying see the example below The warning is suppressed when lint is invoked with h 1 void fun 2 3 char p q 4 int a 0 b 0 c 0 d 0 i 5 si a b amp amp c d 6 i c d amp amp a b 7 if a b 8 i 1 9 while pt q 10 while a b 1 1 while a getchar b 12 if a foo return 13 5 warning assignment operator found where was expected 7 warning assignment operator found where was expected 10 warning assignment operator found where was expected bitwise operation on signed value nonportable Format Compound The operand of a bitwise operator was a variable of signed integral type as defined by ANSI C Because these operators return values that depend on the internal representations of integers their behavior is implementation defined for operands of that type The message is issued only when lint is invoked with Xc k k gt gt 4 I fun 2 3 int i 4 signed int j 5 unsigned int k
274. ibutes of the sections that fall under each segment The sections themselves are in circles 4 31 Compilation Systems Volume 1 Tools Entrance Criteria PROGBITS AIW PROGBITS AW NOBITS 2AW NOTE gt NO MATCH appended to end of a out Segment Attribute Descriptors text LOAD 2RX data LOAD RWX Output Section Descriptors Y data PROGBITS AWX Y data PROGBITS 2AWX Y data2 PROGBITS 2AWX Y bss NOBITS 2AWX Figure 4 3 Simple Map Structure 1d performs the following steps when mapping sections to segments 4 32 bss from rover o note NOTE data1 from rover o Sections Placed in Segments 1 When a section is read in 1d checks the list of Entrance Criteria looking for a match All specified criteria must match In Figure 4 3 for a section to fall into the text segment it must have a section_type value of SPROGBITS and have a section_flags value of A W It need not have the name text since no name is specified in the Entrance Criteria The section may be either X or X in the section flags value since nothing was specified for the execute bit in the Entrance Criteria If no Entrance Criteria match is found the section is placed at the end of the a out file after all other segments No progra
275. ical expression always false op amp amp ocooooocococoooooooooooo 10 26 logical expression always true op UU 2 2 eee eee 10 26 malformed format string 0 2 0 2 cee eee eee 10 27 may be indistinguishable due to truncation or case 00 0000 10 27 name declared but never used or defined e 000000000008 10 27 name defined but never used ooo 10 28 name multiply defined 0 00 eee 10 28 name used but not defined 02 0 eee ee eee 10 28 nonportable bit field type 2 0 Le eee eee 10 29 nonportable character constant lese 10 29 only 0 or 2 parameters allowed main 0 2 0 eee eee eee 10 29 pointer cast may result in improper alignment 004 10 30 pointer casts may be troublesome 0 2 0 0 cece ee eee 10 30 precedence confusion possible parenthesize 00 00005 10 31 precision lost in bit field assignment 00 00 0000 eee eee eee 10 31 set but not used in function eres 10 32 statement has no consequent else eee 10 32 statement has no consequent if 0 0 2 eee eee eee 10 32 statement has null effects nenene ae a E E ee eee 10 33 statement not reached iii ld Ue Rene a 10 33 StatiCUNUSE ans en as a Dea aod 10 34 suspicious comparison of char with value op 0p 0004 10 34 suspicious comparison of unsigned with value op 0p2 10 35 too few arguments for format
276. ie 1B SLB Invalidate Entry optional Supervisor Level slbiex 1B SLB Invalidate Entry by Index optional not on 620 Supervisor Level sld rA rS rB Shift Left Doubleword sldi rA rS n Shift Left Doubleword Immediate Same as rldicl rS rS n 63 n sle TAS 1B Shift Left Extended 601 only k sleq TA IS rB Shift Left Extended with MQ 601 only slig TA IS SH Shift Left Immediate with MQ 601 only P slliql TA IS SH Shift Left Long Immediate with MQ 601 only 2 sliqr rA 1S rB Shift Left Long with MQ 601 only fd slq TAS IB Shift Left with MQ 601 only 5 slw rA rS rB Shift Left Word sl slwil rA rS n Shift Left Word Immediate sli Same as rlwinm rA rS n 0 31 n srad rA rS rB Shift Right Algebraic Doubleword sradi rA rS SH Shift Right Algebraic Doubleword Immediate sraiq IAQS SH Shift Right Algebraic Immediate With MQ 601 only sraql TAS 1B Shift Right Algebraic With MQ 601 only A sraw rA rS rB Shift Right Algebraic Word sra srawi rA rS SH Shift Right Algebraic Word Immediate srai srd rA rS rB Shift Right Doubleword srdi rA rS n Shift Right Doubleword Immediate Same as rldicl rS rS 64 n n sre TATS 1B Shift Right Extended 601 only sreal TATS 1B Shift Right Extended Algebraic 601 only sreq TAS IB Shift Right Extended With MQ 601 only 5 srig TA IS SH Shift Right Immediate With MQ 601 only srliq tA 1S SH Shift Right Long Immediate With MQ 601 only srlq T
277. in In state O there is a goto on rhyme causing the parser to enter state 1 In state 1 the input is read and the end marker is obtained indicated by Send in the y output file The action in state 1 when the end marker is seen successfully ends the parse You might want to consider how the parser works when confronted with such incorrect strings as DING DONG DONG DING DONG DING DONG DELL DELL and so on A few minutes spent with this and other simple examples is repaid when problems arise in more complicated contexts Ambiguity and Conflicts 7 12 A set of grammar rules is ambiguous if there is some input string that can be structured in two or more different ways For example the grammar rule expr i expr expr is anatural way of expressing the fact that one way of forming an arithmetic expression is to put two other expressions together with a minus sign between them Unfortunately this grammar rule does not completely specify the way that all complex inputs should be structured For example if the input is xpr xpr xpr the rule allows this input to be structured as either expr expr expr or as xpr xpr Xpr The first is called left association the second right association yacc detects such ambiguities when it is attempting to build the parser Given the input xpr xpr xpr Parsing with yacc consider the problem that confronts the parser When the parser has read the second expr the
278. in home sharedobs That is the directory assigned to LD_RUN_PATH is searched before the directory assigned to LD_LIBRARY_PATH The important point is that because the path name of 1ibfoo so is not hard coded in prog you can direct the dynamic linker to search a different directory when you execute your program In other words you can move a shared object without breaking your application You can set LD_LIBRARY_PATH without first having set LD_RUN_PATH The main difference between them is that once you have used LD_RUN_PATH for an application the dynamic linker will search the specified directories every time the application is executed unless you have relinked the application in a different environment In contrast you can assign different directories to LD_LIBRARY_PATH each time you execute the application LD_LIBRARY_PATH directs the dynamic linker to search the assigned directories before it searches the standard place Directories including those in the optional second list are searched in the order listed See the previous subsection for the syntax Note finally that when linking a set user or set group ID program the dynamic linker will ignore any directories specified by LD_LIBRARY_PATH that are not trusted Trusted directories are built into the dynamic linker and cannot be modified by the application Currently the only trusted directory is usr lib Checking for Run Time Compatibility 4 16 Suppose you have been supp
279. in a function call did not match the return type in the function definition file 1 c int fun p int p return p value type used inconsistently fun fl c 3 int 2 c 4 int variable may be used before set name Format Simple The first reference to an automatic non array variable occurred at a line number earlier than the first assignment to the variable Note that taking the address of a variable implies both a set and a use and that the first assignment to any member of a struct or union implies an assignment to the entire struct or union 1 void fun 2 3 int GERE 4 static int x 5 k ji 6 i id di 7 xX x 1 8 5 warning variable may be used before set j 6 warning variable may be used before set i variable unused in function Format Compound A variable was declared but never used in a function 10 37 Compilation Systems Volume 1 Tools 1 void fun 2 3 int x y 4 static z gt 5 variable unused in function 4 z in fun 3 y in fun 3 x in fun 10 38 11 Performance Analysis Introduction b ont nee MA hea beak este ee eb eee 11 1 analyZe sd a E E feet s Mute ad a eiu e cette 11 1 Information uere ar a en me a Dre 11 1 Statistics neuen run nie 11 3 Profilin go esse a UE be eater eae be nah ee 11 3 Usage ar dd id deese ee ie tne tee alan dats afi e 11 4 Assumptions and Constraints 2 2 2 ee ee eee 11 9 PO te Aa A e ec Sa
280. inal source code and or documentation As other changes are made they too are identified and retained in the file Retrieval of the original or any set of changes is possible Any version of the file as it develops can be reconstructed for inspection or additional modification History information can be stored with each version why the changes were made who made them and when they were made This chapter covers the following topics The basics of creating retrieving and updating an SCCS file Delta numbering how versions of an SCCS file are named SCCS command conventions what rules apply to SCCS commands e SCCS commands the 14 SCCS commands and their more useful arguments SCCS files protection format and auditing of SCCS files Several terminal session fragments are presented in this section Try them all The best way to learn SCCS is to use it A delta is a set of changes made to a file under SCCS custody To identify and keep track of a delta it is assigned an SID SCCS IDentification number The SID for any original file turned over to SCCS is composed of release number 1 and level number 1 stated as 1 1 The SID for the first set of changes made to that file that is its first delta is release 1 version 2 or 1 2 The next delta would be 1 3 the next 1 4 and so on More on delta 14 1 Compilation Systems Volume 1 Tools numbering later At this point it is enough to know that by default SCCS assigns
281. ing run in the object file The default is Qn Remove unlink the input file after assembly is completed Write the version number of the assembler being run on the standard error output Find the m4 preprocessor m and or the file of predefined macros d in directory dir instead of in the customary place Compilation Systems Volume 1 Tools Character Set The standard ASCII characters and special two character combinations comprise the assembly character set When used in identifiers and labels letters are case sensitive That is the symbols VAL25 and va125 are distinct symbols Letters are not case sensitive in instruction and directives mnemonics Thus word and WORD identify the same directive Source Statements Null Statements Source statements may appear on individual lines or multiple statements may be specified on a single line separated by the delimiting character Any statement may be preceded by one or more labels The assembler imposes no limit on the character length of a source line Null statements are empty lines or lines containing only one or more labels Such state ments are ignored by the assembler Alphanumeric Labels Alphanumeric labels consist of the following characters a z A Z 0 9 _ and These labels must not begin with a digit If the assembler A option is used labels may also contain double quoted strings of the preceding character set and the characters
282. inked with your program at execution The environment variable LD_RUN_PATH lets you do that at link time To set LD_RUN_PATH list the absolute path names of the directories you want searched in the order you want them searched Separate path names with a colon Since we are concerned only with the directory home mylibs here the following will do LD_RUN_PATH home mylibs export LD RUN PATH Now the command cc o prog L home mylibs filel c file2 c file3 c lfoo will direct the dynamic linker to search for libfoo so in home mylibs when you execute your program prog The dynamic linker searches the standard place by default after the directories you have assigned to LD_RUN_PATH Note that as far as the dynamic linker is concerned the standard place for libraries is usr 1ib Any executable versions of libraries supplied by the compilation system are kept in usr lib The environment variable LD_LIBRARY_PATH lets you do the same thing at run time Suppose you have moved libfoo so to home sharedobs It is too late to replace home mylibs with home sharedobs in LD_RUN_PATH at least without link editing your program again You can however assign the new directory to LD_LIBRARY_PATH as follows LD LIBRARY PATH home sharedobs export LD_LIBRARY_PATH Now when you execute your program prog 4 15 Compilation Systems Volume 1 Tools the dynamic linker will search for lib oo so first in home mylibs and not finding it there
283. innings of statements are not sufficiently distinctive it may make a false start in the middle of a state ment and end up reporting a second error where there is in fact no error Actions may be used with these special error rules These actions might attempt to reinitialize tables reclaim symbol table space and so forth Error rules such as the above are very general but difficult to control Rules such as stat error vt are somewhat easier Here when there is an error the parser attempts to skip over the statement but does so by skipping to the next semicolon All tokens after the error and before the next semicolon cannot be shifted and are discarded When the semicolon is seen this rule will be reduced and any cleanup action associated with it performed Another form of error rule arises in interactive applications where it may be desirable to permit a line to be reentered after an error The following example input error An void printf Reenter last line input 4 r is one way to do this There is one potential difficulty with this approach The parser must correctly process three input tokens before it admits that it has correctly resynchronized after the error If the reentered line contains an error in the first two tokens the parser deletes the offending tokens and gives no message This is clearly unacceptable For this reason there is a mechanism that can force the parser to believe that e
284. ion lint Ldir lx filel c file2 c The specified directory is searched before the standard place A lint filter is a project specific post processor that typically uses an awk script or similar program to read the output of 1int and discard messages that your project has decided do not identify real problems string functions for instance returning values that are sometimes or always ignored It enables you to generate customized diagnostic reports when lint options and directives do not provide sufficient control over output Two options to Lint are particularly useful in developing a filter Invoking lint with s causes compound diagnostics to be converted into simple one line messages issued for each occurrence of the problem diagnosed The easily parsed message format is suitable for analysis by an awk script Invoking lint with k causes certain comments you have written in the source file to be printed in output and can be useful both in documenting project decisions and specifying the post processor s behavior In the latter instance if the comment identified an expected lint message and the reported message was the same the message might be filtered out To use k insert on the line preceding the code you want to comment the LINTED msg directive where msg refers to the comment to be printed when lint is invoked with k Refer to the list of directives below for what Lint does when k is not invoked for a file
285. ion Assembler as 1 Each system supported by Concurrent Computer Corporation uses a base assembly language that is supported by other vendors of the underlying architecture Extensions are added to this language Link editor 1d 1 The Concurrent link editor produces programs which can use either static linking or dynamic linking Archiver ar 1 The Concurrent archiver is optimized for fast archive operations Post link analyze 1 These tools are unique to Concurrent analyze 1 can be used to optimizer and perform additional optimizations on programs that have been link profiler report 1 edited It can also be used to obtained profiling and timing information for executable programs report 1 provides readable profiling data Profiler prof 1 This tool is the standard UNIX profiling utility It is available but not useful on the supporting hardware platforms Performance NightTrace 1 This tool is unique to and can be purchased from Concurrent Com analyzer puter Corporation It allows users to analyze data and timings in user applications and the kernel See the NightTrace Manual for details Symbolic gdb 1 This is a port of the Free Software Foundation s GNU debugger Con debugger current has added support for the Fortran language and for DWARF symbolic debugging information Symbolic NightView 1 This source level multi lingual multi process debugger is unique to debugger and can be purchased from Concurrent Computer Co
286. ion Systems Volume 1 Tools 5 4 define N 100 define M N defines M as the string N not 100 The general rule is that m4 always strips off one level of single quotes whenever it evaluates something This is true even outside of macros If the word define is to appear in the output the word must be quoted in the input define 1 It s usually best to quote the arguments of a macro to assure that what you are assigning to the macro name actually gets assigned To redefine N for example you delay its evaluation by quoting define N 100 Jerine CON 200 Otherwise define N 100 derine N 200 the N in the second definition is immediately replaced by 100 The effect is the same as saying define 100 200 Note that this statement will be ignored by m4 because only things that look like names can be defined If left and right single quotes are not convenient for some reason the quote characters can be changed with the built in macro changequote changequote In this example the macro makes the quote characters the left and right brackets instead of the left and right single quotes The quote symbols can be up to five characters long The original characters can be restored by using changequote without arguments changequote undefine removes the definition of a macro or built in undefine N Here the macro removes the definition of N Be sure to quote the argumen
287. ion always true op for the constructs it precedes Also CONSTANTCONDITION EMPTY Suppress statement has no consequent else when inserted between the else and semicolon statement has no consequent if when inserted between the controlling expression of the if and semicolon FALLTHRU Suppress fallthrough on case statement for the case statement it precedes Also FALLTHROUGH LINTED msg When k is not invoked suppress every warning pertaining to an intra file problem except argument unused in function declaration unused in block set but not used in function static unused variable unused in function for the line of code it precedes msg is ignored LINTLIBRARY When o is invoked write to a library 1n file only definitions in the c file it heads NOTREACHED Suppress statement not reached for the unreached statements it precedes fallthrough on case statement for the case it precedes that cannot be reached from the preceding case function falls off bottom without returning value for the closing curly brace it precedes at the end of the function 10 11 Compilation Systems Volume 1 Tools PRINTFLIKEn Treat the nth argument of the function definition it precedes as a s printf format string and issue malformed format string for invalid conversion specifications in that argument and function arg
288. ions l l hm 24 74 Location Expressions lesse hh n 24 74 Location Lists ce em EIL XD D RAD E RE 24 77 Base Type Encodings S use UR RU ORARE eee eae 24 TT Accessibility Codes 22 02 2 EID REFERO 24 78 Visibility Codes ie eee aeter nece e reed 24 78 Virtuality Codes een E ERU UU UE ee a s 24 79 Source Languages os eec pa at tere em ea 24 79 Address Class Encodings 0 0c c eee cette eA 24 79 Identifier Case rer dda aise eee eere he eagles 24 80 Calling Convention Encodings 0 0 0 0 0c eee eee eee 24 80 Inline Codes en e Bee ee u ab D eu Ee 24 80 Array Ordering re eee A Res 24 81 Discriminant Lists e tt eee ola aD 24 81 Name Lookup Table oseiro e cece eee 24 81 Address Range Table ate wee ee ess 24 82 Line Number Information 24 82 Macro Information 0 00 eee ect e a 24 83 Call Frame Information 0 0 cece ce eee 24 83 Dependencies coo ee Re Fee b Lea e 24 84 Future Directions o eMe ee es 24 85 Appendix 1 Current Attributes by Tag Value 000 24 85 Appendix 2 Organization of Debugging Information 24 96 Appendix 3 Statement Program Examples 0 000005 24 99 Appendix 4 Encoding and decoding variable length data 24 100 Appendix 5 Call Frame Information Examples 24 102 Chapter 25 DWARF Access Library libdwarf Introduction 0 t Cea d eee RR RR t e a Ca
289. is dropped before a vertical bar Thus the grammar rules A B C D A E F A G H can be given to yacc as A C D F r Q H w by using the vertical bar Itis not necessary that all grammar rules with the same left side appear together in the grammar rules section although it makes the input more readable and easier to change If a non terminal symbol matches the empty string this can be indicated by epsilon 7 The blank space following the colon is understood by yacc to be a non terminal symbol named epsilon Names representing tokens must be declared This is most simply done by writing token namel name2 name3 and so on in the declarations section Every name not defined in the declarations section is assumed to represent a non terminal symbol Every non terminal symbol must appear on the left side of at least one rule Of all the non terminal symbols the start symbol has particular importance By default the symbol is taken to be the left hand side of the first grammar rule in the rules section It is possible and desirable to declare the start symbol explicitly in the declarations section using the start keyword start symbol The end of the input to the parser is signaled by a special token called the end marker The end marker is represented by either a zero or a negative number If the tokens up to but not including the end marker form a construct that matches the start symbol the parser func tion
290. is undefined A text data or section operation causes the current section to become the previous section and the operation specified section to become the current section byte byte value value The specified value s are assembled into consecutive 1 byte locations Each value is of manifest type and is in the range 27 to 28 1 For example byte 21 43 ubyte expression expression The specified expression s are assembled into consecutive 1 byte locations Each expression is of absolute or relocatable type or is an undefined external Each expression is in the range 0 to 28 1 For example ubyte 55 0 sbyte expression expression The specified expression s are assembled into consecutive 1 byte locations Each expression is of absolute or relocatable type or is an undefined external Each expression is in the range 27 to 27 1 For example sbyte 63 34 vbyte vbyte number expression The specified expression is assembled into consecutive number byte locations expression is of manifest or absolute type number is in the range 1 4 inclusive If expression requires more than number bytes the left most bytes are not assembled For example vbyte 3 726 half word short short value value 2 14 The assembler requires that the location counter be evenly divisible by 2 when this directive is used The specified value s are assembled into consecutive 2 byte locations Each va
291. it is not present or null the internal make variable MAKEF LAGS is set to the null string Otherwise each letter in MAKEFLAGS is assumed to be an input flag argument and is processed as such The only exceptions are the p and r flags 2 Read the internal list of macro definitions 3 Read the environment The environment variables are treated as macro definitions and marked as exported in the shell sense 4 Read the makefile s The assignments in the makefi le s override the environment This order is chosen so that when a makefile is read and executed you know what to expect That is you get what is seen unless the e flag is used The e is the input flag argument which tells make to have the environment override the makefile assignments Thus if make e is entered the variables in the environment override the definitions in the makefile Also MAKEFLAGS overrides the environment if assigned This is useful for further invocations of make from the current makefile It may be clearer to list the precedence of assignments Thus in order from least binding to most binding the precedence of assignments is as follows 1 Internal definitions 2 Environment 3 makefile s 4 Command line The e flag has the effect of rearranging the order to 1 Internal definitions 2 makefile s 13 18 Managing File Interactions with make 3 Environment 4 Command line This order is general en
292. ize the updating of some specified targets This is useful when two or more targets modify a common output file such as when inserting modules into an archive or when creating an intermediate file with the same name as is done by lex and yacc If the makefile above contained a MUTEX directive of the form MUTEX x o y o it would prevent make from building x o and y o in parallel 13 5 Compilation Systems Volume 1 Tools Description Files and Substitutions Comments The following section will explain the customary elements of the description file The comment convention is that the symbol and all characters on the same line after it are ignored Blank lines and lines beginning with are totally ignored Continuation Lines If a non comment line is too long the line can be continued by using the symbol which must be the last character on the line If the last character of a line is then it the new line and all following blanks and tabs are replaced by a single blank Comments can be continued on to the next line as well Macro Definitions General Form 13 6 A macro definition is an identifier followed by the symbol The identifier must not be preceded by a colon or a tab The name string of letters and digits to the left of the trailing blanks and tabs are stripped is assigned the string of characters following the leading blanks and tabs are stripped The following are valid macro defi
293. ks out that last character read Third this routine assumes that the comments are not nested which is indeed the case with the C language Using lex with yacc If you work on a compiler project or develop a program to check the validity of an input language you may want to use the UNIX system tool yace see Chapter 7 Parsing with yacc yace generates parsers programs that analyze input to insure that it is syntactically correct lex often forms a fruitful union with yace in the compiler development context Whether or not you plan to use lex with yacc be sure to read this section because it covers information of interest to all lex programmers As noted a program uses the lex generated scanner by repeatedly calling the function yy lex This name is used because a yacc generated parser calls its lexical analyzer with this very name To use lex to create the lexical analyzer for a compiler you want to end each lex action with the statement return token where token is a defined term whose value is an integer The integer value of the token returned indicates to the parser what the lexical analyzer has found The parser called yyparse by yacc then resumes control and makes another call to the lexical analyzer when it needs another token In a compiler the different values of the token indicate what if any reserved word of the language has been found or whether an identifier constant arithmetic operator or relational operato
294. l Definitions on page 2 16 integer e Asa special symbol The file directive for example can be used to give the symbol a special meaning Refer to Miscellaneous Operations on page 2 18 and Summary of Directives Mnemonics on page 2 19 Integer Constants An integer constant is a 32 bit two s complement number A decimal constant consists of digits from 0 9 and does not possess a leading zero An octal constant consists of digits from 0 7 and possesses a leading zero A hexadecimal constant consists of digits from 0 9 a f and A F leading 0x or 0X For example 914 037775 0x23a Floating Point Constants and possesses a A floating point constant is a 32 bit or a 64 bit number represented in the IEEE format It consists of an optionally signed integer portion a decimal point a fraction portion and an exponent The precision single or double of the constant ultimately depends upon the context in which the constant is assembled The following conventions help the assembler disambiguate certain floating point constants from identifiers beginning with and a digit A leading Of or OF identifies a single precision constant while a leading Od or 0D identifies a double precision constant Floating point constants may begin with one of these prefixes making th optional or they must possess an integer portion e integer portion The fraction portion may be omitted Either the decimal point and the fraction
295. l search the directories named in it before its default directory for shared objects to be linked with the program at execution The environment variable LD_RUN_PATH containing a directory list may also be used to specify library search directories to the dynamic linker If present and not null it is passed to the dynamic linker by 1d via data stored in the output object file 4 7 Compilation Systems Volume 1 Tools Basics of Linking If any argument to 1d is a library it is searched exactly once by default at the point it is encountered in the argument list The library may be either a relocatable archive or a shared object For an archive library only those routines defining an unresolved external reference are loaded The archive library symbol table see ar 4 is searched sequentially with as many passes as are necessary to resolve external references that can be satisfied by library members Thus the ordering of members in the library is functionally unimportant unless there exist multiple library members defining the same external symbol A shared object consists of a single entity all of whose references must be resolved within the executable being built or within other shared objects with which it 1s linked NOTE Because we try to cover the widest possible audience in this section it may provide more background than many users will need to link their programs with a C language library If you are interested only in th
296. le compose double int uw int lw FRT float compose float int w get fpscr double RA RT unsigned int get thread reg Generate a double precision floating point constant given the bit patterns of the two words Generate a single precision floating point constant given the bit pattern of the word Do an mf fs and store it in a memory location pointed to by RA without modifying any floating point registers Get value of the thread register 3 37 Compilation Systems Volume 1 Tools Table 3 8 Compiler Intrinsics Cont Intrinsic Description RT unsigned int inst clcs int RA RA int inst cntlzw int RS inst dcbf void RA int inst dcbi void RA int inst dcbst void inst dcbt void inst dcbtst void inst dcbz void RA int inst dsa void RT int inst eciwx i RB RB nt RA int RB inst ecowx int RS int RA int RB inst eieio void inst esa void FRT float inst fres double FRB FRT double inst frsqrte double FRB FRT double inst fsel double FRA double FRC double FRB inst icbi void RA int RB inst isync void RT sho int RB RT int RT int RT int RT int int RB rt inst lhbrx short inst lwarx int RA i inst lwbrx int RA i inst maskir int RT i FRT double inst mffs void RT int __inst_mfmsr void RT int inst mfspr int spr RT int inst mfsr in
297. lex follows the rule that it matches the longest character string possible and executes the rule for that Here the scanner would recognize the gt and act accordingly As a further example the rule would enable you to distinguish from in a C program Still another potential problem exists when the analyzer must read characters beyond the string you are seeking because you cannot be sure that you ve in fact found it until you ve read the additional characters These cases reveal the importance of trailing context The classic example here is the DO statement in Fortran In the statement DO 50 k 1 20 1 we cannot be sure that the first 1 is the initial value of the index k until we read the first comma Until then we might have the assignment statement DO50k 1 Remember that Fortran ignores all blanks The way to handle this is to use the slash which signifies that what follows is trailing context something not to be stored in yytext because it is not part of the pattern itself So the rule to recognize the Fortran DO statement could be DO 0 9 a zA Z0 9 a zA Z0 9 printf found DO 6 9 Compilation Systems Volume I Tools lex Routines 6 10 Different versions of Fortran have limits on the size of identifiers here the index name To simplify the example the rule accepts an index name of any length See Start Conditions on page 6 13 for a discussion of 1lex s similar han
298. lied with an updated version of a shared object You have already compiled your program with the previous version the link editor has checked it for undefined symbols found none and created an executable According to everything we have said you should not have to link your program again The dynamic linker will simply use the definitions in the new version of the shared object to satisfy unresolved external references in the executable Suppose further that this is a database update program that takes several days to run You want to be sure that your program does not fail in a critical section because a symbol that was defined by the previous version of the shared object is no longer defined by the new version In other words you want the information that the link editor gives you that your executable is compatible with the shared library without having to link edit it again There are two ways you can check for run time compatibility The command 1dd 1 list dynamic dependencies directs the dynamic linker to print the path names of the shared objects on which your program depends ldd prog When you specify the d option to 1dd 1 the dynamic linker prints a diagnostic message for each unresolved data reference it would encounter if prog were executed When you specify the r option it prints a diagnostic message for each unresolved data or function reference it would encounter if prog were executed You can do the same thing wh
299. list If these conditions are not satisfied processing is terminated and the delta is not removed Once a specified delta has been removed its type indicator in the delta table of the SCCS file is changed from D delta to R removed The cdc Command The cdc command is used to change the commentary made when the delta was created It is similar to the rmdel command for example r and full SID are necessary although the delta need not be a leaf delta For example cde r3 4 s abc specifies that the commentary of delta 3 4 is to be changed New commentary is then prompted for as with delta The old commentary is kept but it is preceded by a comment line indicating that it has been superseded and the new commentary is entered ahead of the comment line The inserted comment line records the login name of the user executing cdc and the time of its execution The edc command also allows for the insertion of new and deletion of old MR numbers with the symbol Thus cde r1 4 s abc MRs mrnum3 mrnuml The MRs prompt appears only if the v flag has been set comments deleted wrong MR no and inserted correct MR no inserts mrnum3 and deletes mrnum1 for delta 1 4 The what Command 14 24 The what command is used to find identifying information in any UNIX system file whose name is given as an argument No key letters are accepted The what command searches the given file s for all occurrences of the string 4 which i
300. lloctest File Function Line alloc c mymalloc 33 return alloctest malloc unsigned size alloc c mycalloc 43 return alloctest calloc unsigned nelem unsigned size alloc c myrealloc 53 return alloctest realloc p unsigned size Bands this iG symbol Find this global definition Find functions called by this function Find functions calling this function Find this text string Change this text string Find this egrep pattern Find tirs files Find files including this file Screen 9 6 cscope Lists Functions That Call alloctest Now you want to know which functions call mymal loc escope finds ten such functions It lists nine of them on the screen and instructs you to press the space bar to see the rest of the list 9 7 Compilation Systems Volume 1 Tools Functions calling this function mymalloc File Function Line ario e stralloc 24 return strcpy mymalloc strlen s 1 s crossref c crossref 47 symbol struct symbol mymalloc msymbols sizeof struct symbol Are makevpsredirs 63 stedirs char mymalloc nsredirs sizeof char BODE ARAS addincdir incdirs char mymalloc sizeof char Stellar addincdir incnames char mymalloc sizeof char PALEC addsrcfile p struct listitem mymalloc sizeof struct listitem 7 display c dispinit displine int mymalloc mdisprefs SACO erie yy er 8 history c addcmd h struct cmd mymalloc size
301. lock and data accesses gathered at each load or store instruction The report program can be used to generate various reports that include this information Turn on the specified debug flag You will not be interested in using this unless you know a lot about the inner details of analyze Print a summary of the command usage Set the list of routines to be analyzed to the empty set This overrides the default setting which corresponds to A above Generate a new program file in file which has been optimized by replacing many of the two instruction sequences which are required to reference global memory locations with single instructions which use the reserved linker registers r28 through r31 as base registers This allows faster access to the four most commonly referenced 64K data blocks Certain library routines that are known to access the linker registers e g set jmp and long jmp are automatically excluded from the optimization process The X option may be used to specifically exclude others Normally any reference to a linker register will cause an error Generate a new program file in file which has been patched to gather profiling statistics on each basic block and dump them to file prof on exit The report program can be used to generate various reports from this information The X option may be useful with this option Analyze section instead of text Declare routine to be the name of a subroutine which causes the
302. log Structure of Manuals A brief description of the parts chapters and appendixes in the Compilation Systems Volume I Tools manual follows Part discusses software development environment tools Chapter 1 introduces compilation system tools and concepts Chapter 2 describes the assembly language and it discusses the assembler as Chapter 3 summarizes the instructions condition codes operands and registers associated with the PowerPC Chapter 4 covers the link editor 1d It also discusses dynamic linking plus the creation and use of shared objects Chapter 5 describes the macro processor m4 Chapter 6 presents the lexical analyzer lex Chapter 7 presents the compiler compiler yace Part 2 describes analysis tools Chapter 8 provides an introduction to the other chapters in this part Chapter 9 presents the C code browser cscope Chapter 10 discusses the C code checker lint Chapter 11 discusses performance analysis and use of the analyze and report utilities Part 3 presents project control tools iii Compilation Systems Volume 1 Tools Chapter 12 provides an introduction to the other chapters in this part Chapter 13 presents the make utility Chapter 14 covers the sees source code control system A brief description of the parts chapters and appendixes in the Compilation Systems Volume 2 Concepts manual follows Part 4 discusses environments Chapter 15 provides an introduction to the other ch
303. lt libraries are located in lib usr lib and usr ccs lib Produce a map or listing of the input output sections on the standard output Produce an output object file by the name outfile The name of the default object file is a out Combine relocatable object files to produce one relocatable object file 1d will not complain about unresolved references This option cannot be used in dynamic mode or with a Relocation entries are retained in the output file so that it can become an input file in a subsequent 1d run Strip symbolic information from the output file Debug and line information and their associated relocation entries will be removed Except for relocatable files or shared objects the symbol table and string table sections will also be removed from the output object file Relocation entries will not be saved when this option is used u symname Vv X zdefs Link Editor and Linking Turn off the warning about multiply defined symbols that are not the same size Enter symname as an undefined symbol in the symbol table This is useful for loading entirely from an archive library since initially the symbol table is empty and an unresolved reference is needed to force the loading of the first routine The placement of this option on the command line is significant it must be placed before the library that will define the symbol Same as V Do not preserve local symbols with type STT NOTYPE This
304. lue When the value is referenced through a or n construction yace will automatically insert the appropriate union name so that no unwanted conversions take place There are three mechanisms used to provide for this typing First there is a way of defining the union This must be done by the user since other subroutines notably the lexical analyzer must know about the union member names Second there is a way of associating a union member name with tokens and non terminals Finally there is a mechanism for describing the type of those few values where yace cannot easily determine the type To declare the union you include 7 27 Compilation Systems Volume I Tools 7 28 Sunion body of union in the declaration section This declares the yace value stack and the external variables yylval and yyval to have type equal to this union If yace was invoked with the d option the union declaration is copied into the y tab h file as YYSTYPE Once YYSTYPE is defined the union member names must be associated with the various terminal and non terminal names The construction lt name gt is used to indicate a union member name If this follows one of the keywords token left stright and nonassoc the union member name is associated with the tokens listed Thus saying left lt optype gt causes any reference to values returned by these two tokens to be tagged with the union member name optype Another
305. lue is of manifest type and is in the range 215 to 216 1 For example Assembler and Assembly Language half 0x56b uhalf expression expression The location counter must be evenly divisible by 2 when this directive is used The specified expression s are assembled into consecutive 2 byte locations Each expression is of absolute or relocatable type or is an undefined external Each expression is in the range 0 to 216 1 For example uhalf 1078 457 3 shalf expression expression The location counter must be evenly divisible by 2 when this directive is used The specified expression s are assembled into consecutive 1 byte locations Each expression is of absolute or relocatable type or is an undefined external Each expression 1s in the range 215 to 215 1 For example shalf 20345 26 uahalf value value There is no restriction on the divisibility of the location counter when this directive is used The specified value s are assembled into consecutive 2 byte locations Each value is of absolute type and is in the range 215 to 0 to 216 1 For example uahalf 7823 40201 word int long value value The location counter must be evenly divisible by 4 when this directive is used The specified value s are assembled into consecutive 4 byte locations Each value is of manifest type and is in the range 231 to 237 1 For example word 3 759323 0 uaword expression expression The
306. lume 1 Tools Position Independent Position Dependent section tdesc x section tdesc x word 0x42 word 0x42 word 0x2 word 0x1 word be rel word be word en rel word en word 0x1020021 word 0x1000021 word 0x50 word 0x50 word 0x8 word 0x8 word OxfffffffO word OxfffffffO 2 24 For executable code in a shared object to be shared among multiple processes using that shared object it must reference symbols and data in a position independent manner In the code above the addressing base is computed into register r14 Because each process will have its own private copy of the global offset table for procedures the address of g1obal ptr specific to a process can be obtained from the process private copy of the table The global_ptr got_rel syntax directs the assembler to produce relocation information that the link editor will use The link editor will establish an offset in the global offset table which will contain the address of global ptr The value in register r3 contains a byte offset from the addressing base to this location in the table The value in r5 is the address of g1obal ptr Thus an extra level of indirection is needed to obtain the address of the variable An explanation of the use of Qgotp rel for referencing malloc is similar The be rel syntax directs the assembler and the link editor to produce a value which is the difference between the address of the symbol be and the addressing base of the shared obj
307. m header entry is created for this information See Chapter 22 Executable and Linking Format ELF for information on program headers Link Editor and Linking 2 When the section falls into a segment 1d checks the list of existing Output Section Descriptors in that segment as follows If the section attribute values match those of an existing Output Section Descriptor exactly the section is placed at the end of the list of sections associated with that Output Section Descriptor e For instance a section with a section_name value of datal a section_type value of SPROGBITS and a section_flags value of AWX falls into the second Entrance Criteria box in Figure 4 3 placing it in the data segment The section matches the second Out put Section Descriptor box exactly datal PROGBITS AWX and is added to the end of the list associated with that box The datal sections from fido o rover o and sam o illustrate this point If no matching Output Section Descriptor is found but other Output Section Descriptors of the same section type exist a new Output Section Descriptor is created with the same attribute values as the section and that section is associated with the new Output Section Descriptor The Output Section Descriptor and the section are placed after the last Output Section Descriptor of the same section type The data2 section in Figure 4 3 was placed in this manner If no other Output Section Descriptor
308. m identifiers Identifiers have a maximum length of 1024 characters Examples of identifiers include L5 _subroutine_ Each identifier symbol may be classified as either predefined by the assembler or user defined Predefined Symbols 2 6 These symbols possess specific meanings for the assembler They cannot be redefined by the user nor may they be used outside their specific contexts Predefinitions Instruction mnemonics Assembler directives see Assembler Directives on page 2 12 e General register names rO r31 e Floating point register names 0 31 e Special purpose register names xer lr ctr dsisr dar dec sdrl srr0 srrl sprg0 sprgl sprg2 sprg3 ear pvr ibatOu ibatOl ibatlu ibat11l ibat2u ibat21 ibat3u ibat3l iabr PowerPC 601 specific special purpose register names mg rtcu rtcl dec hidl PowerPC 603 specific special purpose register names dmiss dcmp hashl hash2 imiss icmp rpa e PowerPC 604 specific special purpose register names mmcr0 pmcl pmc2 sia sda PowerPC 620 specific special purpose register names asr mmcrO pmcl pmc2 sia sda buscsr l2cr 12sr fpecr Special purpose register names absent from PowerPC 601 tb tbl dbat0u dbatOl dbatlu dbatll dbat2u dbat2l dbat3u dbat3l Assembler and Assembly Language Special purpose register names absent from PowerPC 603 hid0 dabr pir Special purpose register names absent from Powe
309. m implementation defined sign extension shows how a thoughtful application of 1int s portability option can help you discover bugs not related to portability In any case declare c as an int A similar issue arises with bit fields When constant values are assigned to bit fields the field may be too small to hold the value On a machine that treats bit fields of type int as unsigned quantities the values allowed for int x 3 range from 0 to 7 whereas on machines that treat them as signed quantities they range from 4 to 3 However unintuitive it may seem a three bit field declared type int cannot hold the value 4 on the latter machines lint invoked with p flags all bit field types other than unsigned int or signed int Note that these are the only portable bit field types The compilation system supports int char short and long bit field types that may be unsigned signed or plain It also supports the enum bit field type Bugs can arise when a larger sized type is assigned to a smaller sized type If significant bits are truncated accuracy is lost short s long 1 s l lint flags all such assignments by default the diagnostic can be suppressed by invoking the a option Bear in mind that you may be suppressing other diagnostics when you invoke lint with this or any other option Check the list in Usage on page 10 6 for the options that suppress more than one diagnostic e A cast of a pointer to one object t
310. m4 Macro Processor oocococnccccnnnonnnonnnoncnnnonncnncon nono con ener nennen nennen 5 1 Chapter 6 Lexical Analysis with lex 6 1 Chapter 7 Parsing with yacc coocononnnonionconcnnnconncnnonnnnnnona nono noncrano eene eee 7 1 Compilation Systems Volume 1 Tools Introduction Programming Languages 1 Introduction to SDEs Compilation Systems Concepts llle eee Concurrent Computer Corporation Compilation Systems 222222200 Object Files Stack Frames Static and Dynamic Linking oooooocoocococorro e Floating Point Arithmetic 1 1 1 1 1 2 1 3 1 5 1 6 1 7 Compilation Systems Volume 1 Tools Introduction Introduction to SDEs 1 Introduction to SDEs To create a program you must be working in and understand some aspects of a software development environment SDE A software development environment includes the hard ware operating system supported object and debugging information formats compilers and utilities This part of the manual discusses some of the tools available in the software development environment Chapter 2 Assembler and Assembly Language covers the instruction mnemonics and 1 assembler implementation for the supporting hardware platforms Chapter 3 PowerPC Instruction Set Summary summarizes the instructions condition codes operands and registers associated with the PowerPC Chapter 4 Link Edit
311. make more general use of the wealth of information that make generates Recursive Makefiles 13 8 Another feature of make concerns the environment and recursive invocations If the sequence MAKE appears anywhere in a shell command line the line is executed even if the n flag is set Since the n flag is exported across invocations of make through the MAKEF LAGS variable the only thing that is executed is the make command itself This feature is useful when a hierarchy of makefiles describes a set of software subsystems Managing File Interactions with make For testing purposes make n can be executed and everything that would have been done will be printed including output from lower level invocations of make Suffixes and Transformation Rules Implicit Rules make uses an internal table of rules to learn how to transform a file with one suffix into a file with another suffix If the r flag is used on the make command line the internal table is not used The list of suffixes is actually the dependency list for the name SUFFIXES make searches for a file with any of the suffixes on the list If it finds one make transforms it into a file with another suffix Transformation rule names are the concatenation of the before and after suffixes The name of the rule to transform a r file to a o file is thus r o If the rule is present and no explicit command sequence has been given in the user s description files
312. mat Compound A non void function did not contain a return statement yet was used for its value in an expression file 1 c 1 extern int fun main return fun function value is used but none returned fun 10 25 Compilation Systems Volume 1 Tools logical expression always false op amp amp Format Simple A logical AND expression checked for equality of the same variable to two different con stants or had the constant 0 as an operand In the latter case preceding the expression with CONSTCOND suppresses the message 1 void fun a 2 int a 3 4 a a 1 amp amp a 2 5 a a 1 amp amp a 1 6 a 1 a amp amp a 2 7 a a 1 amp amp 0 8 CONSTCOND 9 a 0 amp amp a 1 KOL e Sp 4 warning logical expression always false op amp amp 6 warning logical expression always false op amp amp 7 warning logical expression always false op amp amp logical expression always true op Format Simple A logical OR expression checked for inequality of the same variable to two different con stants or had a nonzero integral constant as an operand In the latter case preceding the expression with CONSTCOND suppresses the message 1 void fun a 2 int a 3 4 a dt d 2 5 a a 1 a l 1 6 a 1 a a 2 7 a a 10 1 8 CONSTCOND 9 a 1 a 10
313. matically and the conflicts even more dramatically Thus it is better practice in a more normal programming 7 33 Compilation Systems Volume I Tools 7 34 language environment to keep the type information as part of the value and not as part of the grammar Finally a word about the lexical analysis The only unusual feature is the treatment of floating point constants The C language library routine atof is used to do the actual conversion from a character string to a double precision value If the lexical analyzer detects an error it responds by returning a token that is invalid in the grammar provoking a syntax error in the parser and thence error recovery include lt stdio h gt include lt ctype h gt typedef struct interval doubles doe niy INTERVAL INTERVAL vmul vdiv double atof double dreg 26 INTERVAL vreg 26 start lines union abajo stay double dval INTERVAL vval token lt ival gt DREG VREG indices into dreg vreg arrays token lt dval gt CONST floating point constant Stype lt dval gt dexp expression Stype lt vval gt vexp interval expression precedence information about the operators Slere tat a ai left beginning of rules section lines 8 empty lines line dexp n void print 15 8 n 1 vexp n void printf 15 8f 15 8 1n 1 10 1 hi DREG dexp n dreg 1
314. ment Count Zero to LR bdzr 1 Same as bclr 1 18 0 bdzt 1 a BLBD Branch Decrement Count Zero True Same as bc 1 a 10 BI BD bdztlr 1 BI Branch Decrement Count Zero True to LR Same as bclr 1 10 BI bf 1 a BLBD Branch False bbf 1 a Same as bc 1 a 4 BI BD bfctr 1 BI Branch False to Count Register bbfc 1 Same as bcctr 1 4 BI bflr 1 BI Branch False to Link Register bbfr 1 Same as bclr 1 4 BI blr 1 Branch to Link Register br 1 Same as bclr 1 20 0 bt 1 a BLBD Branch True bbt 1 a Same as bc 1 a 12 BI BD btctr 1 BI Branch True to Count Register bbtc 1 Same as bcctr 1 12 BI btlr 1 BI Branch True to Link Register bbtr 1 Same as bclr 1 12 BI bCC I a crfA BD Branch on Condition Code gt crfA defaults to crf0 Same as bc 1 a BO BI BD bCCctr 1 crfA Branch on Condition Code to Count Register bCCell crfA defaults to crf0 Same as bcctr 1 BO BI bCCIr 1 crfA Branch on Condition Code to Link Register bCCr l crfA defaults to crf0 Same as bclr 1 BO BI cles TTrA Cache Line Compute Size 601 only clridi rA rS n Clear Left Doubleword Immediate Same as rldicl rA rS 0 n clrIsdi rA rS b n Clear Left and Shift Doubleword Immediate Same as rldicr rA rS n b n clrlslwi rA rS b n Clear Left and Shift Left Word Immediate n lt b lt 31 Same as rlwinm rA rS n b n 31 n 3 4 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC Mne
315. ments remaining in the call See also PRINTF LIKEn and SCANFLIKI En in the list of directives in Usage on page 10 6 10 35 Compilation Systems Volume 1 Tools 1 include lt stdio h gt 2 main 3 4 int i 5 printf d d i 6 guments for format test c 5 O O mh 0 y Tn ES too many arguments for format Format Compound A control stringofa fs printf or fs scanf function call had fewer conversion specifications than there were arguments remaining in the call See also PRINTF LIKEn and SCANFLIKEn in the list of directives in Usage on page 10 6 1 include lt stdio h gt 2 main 3 4 int iz y 5 printf d i J 6 too many arguments for format printf test c 5 value type declared inconsistently 10 36 Format Compound The return type in a function declaration or definition did not match the return type in another declaration or definition of the function The message is also issued for inconsis tent declarations of variable types file 1 c i void fun 2 void foo 3 extern int a file 2 c ih extern int fun 2 extern int foo 3 extern char a value type declared inconsistently fun fl c 1 void f2 c 1 int foo fl c 2 void f2 c 2 int a fl c 3 rnt ry f2 c 3 char Analyzing Your Code with lint value type used inconsistently Format Compound The return type
316. monic Syntax of Operands Description RS 6000 POWER Mnemonic clrlwi clrrdi clrrwi cmp cmpd cmpdi cmpi cmpw cmpwi cmpl cmpld cmpldi cmpli cmplw cmplwi rA rS n rA rS n rA rS n crfT L rA rB crfT rA rB crf T rA SI crf T L rA SI crf T rA rB crf T rA SI crfT L rA rB crf T rA rB crf T rA UI crf T LorA UI crf T rA rB crf T rA UI Clear Left Word Immediate n 3l Same as rlwinm rA rS 0 n 31 Clear Right Doubleword Immediate Same as rldicl rA rS 0 63 n Clear Right Word Immediate n lt 31 Same as rlwinm rA rS 0 0 31 n Compare crfT defaults to crf0 Compare Doubleword crfT defaults to crfO Same as cmp crfT l rA rB Compare Doubleword Immediate crfT defaults to crfO Same as cmpi crfT 1 rA SI Compare Immediate crfT defaults to crf0 Compare Word crfT defaults to crfO Same as cmp crfT 0 rA rB Compare Word Immediate crfT defaults to crfO Same as cmpi crfT 0 rA SI Compare Logical crfT defaults to crf0 Compare Logical Doubleword crfT defaults to ctfO Same as cmpl crfT 1 rA rB Compare Logical Doubleword Immediate crfT defaults to crfO Same as cmpli crfT 1 rA UI Compare Logical Immediate crfT defaults to crf0 Compare Logical Word crfT defaults to crfO Same as cmpl crfT 0 rA rB Compare Logical Word Immediate crfT defaults to crfO Same as cmpli crfT 0 rA UI cmp
317. mple admin ifirst fi fmmodname s abc sets the i and m module name flags The value modname specified for the m flag is the value that the get command will use to replace the M ID keyword In the absence of the m flag the name of the g file is used as the replacement for the M ID keyword Several key letters may be supplied on a single admin and they may be used whether the command is creating a new SCCS file or processing an existing one admin dis used to delete a flag from an existing SCCS file As an example the command admin dm s abc removes the m flag from the SCCS file Several d key letters may be used with one admin and may be intermixed with SCCS files contain a list of login names and or group IDs of users who are allowed to create deltas This list is empty by default allowing anyone to create deltas To create a user list or add to an existing one admin a is used For example admin axyz awql al234 s abc adds the login names xyz and wql and the group ID 1234 to the list admin a may be used whether creating a new SCCS file or processing an existing one admin e erase is used to remove login names or group IDs from the list The prs Command The prs command is used to print all or part of an SCCS file on the standard output If prs dis used the output will be in a format called data specification Data specification is a string of SCCS file data keywords not to be confused with ge
318. mtspr 956 rS mtmq TS Move To Multiply Quotient Register 601 only Same as mtspr O rS mtmsr IS Move To Machine State Register Supervisor Level mtpir rS Move To Processor ID Register optional not on 602 603 e Supervisor Level Same as mtspr 1023 rS mtpmc1 IS Move To Performance Monitor Counter 1 604 e 620 only Supervisor Level Same as mtspr 953 18 mtpmc2 IS Move To Performance Monitor Counter 2 604 e 620 only Supervisor Level Same as mtspr 954 rS mtpmc3 rS Move To Performance Monitor Counter 3 604e only Supervisor Level Same as mtspr 957 rS mtpmc4 rS Move To Performance Monitor Counter 4 604e only Supervisor Level Same as mtspr 958 rS mtrpa TS Move To Required Physical Address 602 603 e only Supervisor Level Same as mtspr 982 rS mtrtcl IS Move To Real Time Clock Lower 601 only Same as mtspr 21 rS miricu IS Move To Real Time Clock Upper 601 only E Same as mtspr 20 rS mtsda IS Move To Sampled Data Address Register 604 e 620 only Supervisor Level Same as mtspr 959 18 mtsdrl IS Move to Storage Description Register 1 Supervisor Level Same as mtspr 25 18 3 18 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC RS 6000 f Syntax of Operands Description POWER Mnemonic Mnemonic mtsebr IS Move To Special Execute Base Register 602 only Supervisor Level Same as mtspr 990 rS mtser IS Move To Special Execute Register 602
319. n Specific and Optional Instructions Table 3 7 Implementation Specific and Optional Instructions Mnemonic 601 602 603 e 604 e 620 750 abs o I v cles v clrisdi v elridi v clrrdi v cmpd v cmpdi v cmpld v cmpldi v entlzd v div o v divd o v divdu o v divs o I v doz o v dozi v dsa v eciwx v v v v v ecowx v v v v v esa v extldi v extrdi v 3 31 Compilation Systems Volume 1 Tools Table 3 7 Implementation Specific and Optional Instructions Cont Mnemonic 601 602 603 e 604 e 620 750 extsw fadd v v v fefid fctid fctidz fdiv fmadd fmsub fmul fnmadd fnmsub fres v frsp frsqrte v fsel v fsqrt s fsub v S S S S S x SUSSSNSNSSNSS S S S S S S S S S S S S S S S S S S S S S x x x insrdi ld u Id u x Idarx Ifd u Ifd u x Iscbx S S S S S S S S S S S S S S S S S S S S S S S S Iswi S S S 88 Iswx lwa S S S Iwax maskgl v maskir v mfasr v mfbatl v mfbatu v 3 32 PowerPC Instruction Set Summary Table 3 7 Implementation Specific and Optional Instructions Cont Mnemonic 601 602 603 e 604 e 620 750 mfbuscr v mfdabr v v v v mfdbatl v v v v v mfdbatu v v v v v mfdcmp v v mfdmiss v v mfear v v v v v mfesasrr v mffpecr v mfhash1 v v mfhash2 v v mfhidO v v v v v v mfhidl v v 603e 604e v mfiabr v v v v v v mfib
320. n defined The message is issued only when lint is invoked with p void fun c d signed char d 1 2 char c 3 4 5 int 6 i 7 i 8 i 9 i x d 6 warning constant op 7 warning suspicious comparison of unsigned Format Simple suspicious comparison of char with 0 Analyzing Your Code with lint suspicious comparison of char with negative op mon with value op op A comparison was performed on a variable of unsigned type that implied it may have a negative value 0 lt 0 gt 0 gt 0 1 void fun x 2 unsigned x 3 4 int i 5 i x gt 2 6 i x lt 0 d i x lt 0 8 i x gt 0 9 i x gt 0 10 ij 22 x 11 i x 1 12 i x 1U 13 j 5 warning suspicious comparison of unsigned with negative constant op gt 6 warning suspicious comparison of unsigned with 0 op ou 7 warning suspicious comparison of unsigned with 0 op lt 8 warning suspicious comparison of unsigned with 0 op gt 9 warning suspicious comparison of unsigned with 0 op wou 10 warning suspicious comparison of unsigned with negative constant op lt 11 warning suspicious comparison of unsigned with negative constant op too few arguments for format Format Compound A control string ofa fs printf or fs scanf function call had more conversion specifications than there were argu
321. n lines beginning with an sign are printed Touch the target files causing them to be up to date rather than issue the usual commands Question The make command returns a zero or nonzero status code depending on whether the target file is or is not up to date Print out the complete set of macro definitions and target descrip tions Abandon work on the current entry if something goes wrong but continue on other branches that do not depend on the current entry Environment variables override assignments within makefiles Description file name makefile is assumed to be the name of a description file A makefile of denotes the standard input If there are no f arguments the file named makefile Make file s makefile or s Makefile in the current directory is read The contents of the description files override the built in rules if they are present Update in parallel more than one target at a time The number of targets updated concurrently is determined by the environment variable PARALLEL and the presence of MUTEX directives in makefiles Unconditionally make the target ignoring all timestamps Absolute or relative path name viewpath to be searched for needed files Suppress warning messages Fatal messages will not be affected The following fake target names are evaluated in the same manner as flags DEFAULT PRECIOUS SILENT IGNOR El If a file must be made but
322. n the user s terminal and is often used with p to pipe the output as in get p s s abc pg get g prints the SID on standard output and there is no retrieval of the SCCS file This is useful in several ways For example to verify a particular SID in an SCCS file get g r4 3 s abc outputs the SID 4 3 if it exists in the SCCS file s abc or an error message if it does not Another use of get g is in regenerating a p file that may have been accidentally destroyed as in get e g s abc get 1 causes SCCS to create 1 file in the current directory with mode 444 read only for owner group and other and owned by the real user The 1 file contains a table whose format is described on get 1 showing the deltas used in constructing a particular version of the SCCS file For example get r2 3 1 s abc generates an 1 file showing the deltas applied to retrieve version 2 3 of s abc Specifying p with 1 as in get lp r2 3 s abc causes the output to be written to the standard output rather than to 1 file get g can be used with 1 to suppress the retrieval of the text get midentifies the changes applied to an SCCS file Each line of the g file is preceded by the SID of the delta that caused the line to be inserted The SID is separated from the text of the line by a tab character Tracking Versions with SCCS get n causes each line of a g file to be preceded by the value of the M ID keyword and a tab character
323. n useful to programmers is to include rules with mnemonic names and commands that do not actually produce a file with that name These entries can take advantage of make s ability to generate files and substitute macros for information about macros see Description Files and Substitutions on page 13 6 Thus an entry save might be included to copy a certain set of files or an entry clean might be used to throw away unneeded intermediate files If a file exists after such commands are executed the file s time of last modification is used in further decisions If the file does not exist after the commands are executed the current time is used in making further decisions You can maintain a zero length file purely to keep track of the time at which certain actions were performed This technique is useful for maintaining remote archives and listings A simple macro mechanism for substitution in dependency lines and command strings is used by make Macros can either be defined by command line arguments or included in the description file In either case a macro consists of a name followed by the symbol followed by what the macro stands for A macro is invoked by preceding the name by the symbol Macro names longer than one character must be parenthesized The following are valid macro invocations CFLAGS 2 xy sz 2 The last two are equivalent 0 and lt are four special macros that change values during
324. nagement process delta y and or m can be used to enter comments and MR numbers on the command line rather than through the standard input as in delta y descriptive comment m mrnumI mrnum2 s abc In this case the prompts for comments and MRs are not printed and the standard input is not read These two key letters are useful when delta is executed from within a shell procedure Note that delta mis allowed only if the SCCS file has a v flag No matter how comments and MR numbers are entered with delta they are recorded as part of the entry for the delta being created Also they apply to all SCCS files specified with the delta If delta is used with more than one file argument and the first file named has a v flag all files named must have this flag Similarly if the first file named does not have the flag none of the files named may have it When delta processing is complete the standard output displays the SID of the new delta from p file and the number of lines inserted deleted and left unchanged For example 1 4 14 inserted 7 deleted 345 unchanged If line counts do not agree with the user s perception of the changes made to a g file 1t may be because there are various ways to describe a set of changes especially if lines are moved around in the g file However the total number of lines of the new delta the number inserted plus the number left unchanged should always agree with the number of lines in th
325. ncement also allows for the expansion of the VPATH as new makefiles are included or referenced through the initial invocation Some limitations on the VPATH include any one path specified cannot be longer than MAXPATHLEN 1 and the maximum number of paths specified regardless of length can not exceed 10 Command Usage Refer to make 1 for detailed information The make Command 13 16 The make command takes macro definitions options description file names and target file names as arguments in the form make f makefile v viewpath eiknpPqrstuw names The following summary of command operations explains how these arguments are interpreted First all macro definition arguments arguments with embedded symbols are analyzed and the assignments made Command line macros override corresponding definitions found in the description files Next the option arguments are examined The permissible options are as follows i Ignore error codes returned by invoked commands This mode is entered if the fake target name IGNORE appears in the descrip tion file S gt E n q P f makefile u v viewpath W Managing File Interactions with make Silent mode Do not print command lines before executing This mode is also entered if the fake target name SILENT appears in the description file Do not use the built in rules No execute mode Print commands but do not execute them Eve
326. nces may disguise errors in the input grammar It is a good idea to be sparing with precedences and use them in a cookbook fashion until some experience has been gained The y output file is useful in deciding whether the parser is actually doing what was intended To illustrate further how you might use the precedence keywords to resolve a shift reduce conflict we ll look at an example similar to the one described in the previous section Consider the following C statement if flag if anotherflag x 1 else x 2 7 18 Parsing with yacc The problem for the parser is whether the else goes with the first or the second if C programmers will recognize that the else goes with the second if contrary to what the misleading indentation suggests The following yace grammar for an if then else construct abstracts the problem That is the input iises will model the C statement shown above nclude lt stdio h gt a je oken SIMPLE IF ELSE stmnt n sso UME LE if_stmnt DES ENTES t PEIE EINS IMPETE ni IF stmnt ELSE stmnt printf if_then_else n c getchar if c EOF return 0 else switch c case de return LE case s return SIMPLE case e return ELSE default return c When the specification is passed to yacc however we get the following message conflicts 1 shift reduce The problem is that when yacc has read iis in trying to match iises it has two choices recognize is as a
327. nction it may already be in memory because of its proximity to other text in the process If the function is in a shared library however the surrounding library code may be unrelated to the calling process Only Link Editor and Linking rarely for example will any single executable use everything in the shared C library If a shared library has unrelated functions and if unrelated processes make random calls to those functions locality of reference may be decreased leading to more paging activity The point is that functions used by only a few a out files do not save much disk space by being in a shared library and can degrade performance Second try to improve locality of reference by grouping dynamically related functions If every call to funcA generates calls to funcB and funcC try to put them in the same page cflow 1 generates this kind of static dependency information Combine it with profiling to see what things actually are called as opposed to what things might be called Align for paging Try to arrange the shared library s object files so that frequently used functions do not unnecessarily cross page boundaries First determine where the page boundaries fall The page size is 4K You can use the nm 1 command to determine how symbol values relate to page boundaries After grouping related functions break them up into page sized chunks Although some object files and functions are larger than a page many are n
328. nd all lowercase letters for non terminal names This is useful in debugging 2 Put grammar rules and actions on separate lines It makes editing easier 3 Put all rules with the same left hand side together Put the left hand side in only once and let all following rules begin with a vertical bar 4 Put a semicolon only after the last rule with a given left hand side and put the semicolon on a separate line This allows new rules to be easily added 5 Indent rule bodies by one tab stop and action bodies by two tab stops 6 Put complicated actions into subroutines defined in separate files Example 1 below is written following this style as are the examples in this section where space permits The central problem is to make the rules visible through the morass of action code Left Recursion The algorithm used by the yace parser encourages so called left recursive grammar rules Rules of the form name x name rest_of_rule match this algorithm Rules such as list item list item 7 and seq E item seq item r frequently arise when writing specifications of sequences and lists In each of these cases the first rule will be reduced for the first item only and the second rule will be reduced for the second and all succeeding items With right recursive rules such as seq item item seq 7 24 Lexical Tie Ins Parsing with yacc the parser is a bit bigger and the items are seen and reduced from
329. nd defining the prototype suppresses the warning if all declarations have the same number of arguments The message immediately preceding this one is issued for uses not declarations or definitions of a prototype with the wrong number of arguments with the ANSI C notation filei3a c 1 int 2 int 3 int 10 22 funl int fun2 int fun3 int Analyzing Your Code with lint file i3b c 1 int funl int int 2 int fun2 int a int b 3 void foo 4 5 Ante ayy Ke 6 i fun3 j k 7 function declared with variable number of arguments fun2 i3a c 2 i 13b c 2 funi i3a c 1 i3b c l function called with variable number of arguments fun3 i3a c 3 13b 6 function falls off bottom without returning value Format Compound A non void function did not return a value to the invoking function If the closing curly brace is truly not reached preceding it with NOTREACHED suppresses the message 1 fun 2 3 void fun2 4 5 foo 6 7 exit 1 8 NOTREACHED 9 function falls off bottom without returning value 2 fun function must return int main Format Simple The program s main function does not return int in violation of ANSI C restrictions The message is issued only when lint is invoked with Xc 1 void main 2 B 2 warning function must return int main 10 23 Compilation Systems Volume 1 Tools f
330. nd lint will give a warning for each of them The shear number of lint messages issued can be distracting lint however provides command line options and directives to help suppress warnings you consider to be spurious NOTE Directives are special comments embedded in the source text For the example we ve cited here You can invoke lint with the b option to suppress all complaints about unreachable break statements For a finer grained control you can precede any unreachable statement with the comment NOTREACHED to suppress the diagnostic for that statement 10 1 Compilation Systems Volume 1 Tools Usage on page 10 6 details options and directives and introduces the lint filter technique which lets you tailor 1int s behavior even more finely to your project s needs It also shows you how to use lint libraries to check your program for compatibility with the library functions you have called in it lint and the Compiler Nearly five hundred diagnostic messages are issued by lint However this chapter only describes those lint specific warnings that are not issued by the compiler Additionally this chapter lists diagnostics issued both by lint and the compiler that are capable of being suppressed only by lint options For the text and examples of all messages issued exclusively by Lint or subject exclusively to its options refer to lint specific Messages on page 10 12 Message Formats
331. nd sequence may be associated with more than one dependency line If the target is out of date with any of the files on a particular line the associated commands are executed A built in rule may also be executed The double colon form is particularly useful in updating archive type files where the target is the archive library itself An example is included in Archive Libraries on page 13 11 Executable Commands If a target must be created the sequence of commands is executed Normally each command line is printed and then passed to a separate invocation of the shell after substituting for macros The printing is suppressed in the silent mode s option of the make command or if the command line in the description file begins with an sign make normally stops if any command signals an error by returning a nonzero error code Errors are ignored if the i flag has been specified on the make command line if the fake target name IGNORE appears in the description file or if the command string in the description file begins with a hyphen If a program is known to return a meaningless status a hyphen in front of the command that invokes it is appropriate Because each command line is passed to a separate invocation of the shell care must be taken with certain commands cd and shell control commands for instance that have meaning only within a single shell process These results are forgotten before the next line is executed B
332. nitions 2 xyz abc 11 ly 1m LIBES The last definition assigns LIBES the null string A macro that is never explicitly defined has the null string as its value Remember however that some macros are explicitly defined in make s own rules The general form of an entry in a description file is target target2 dependentl commands t commands Items inside brackets may be omitted and targets and dependents are strings of letters digits periods and slashes Shell metacharacters such as and are expanded when the commands are evaluated Commands may appear either after a semicolon on a dependency line or on lines beginning with a tab denoted above as t immediately Managing File Interactions with make following a dependency line A command is any string of characters not including except when is in quotes Dependency Information A dependency line may have either a single or a double colon A target name may appear on more than one dependency line but all of those lines must be of the same single or double colon type For the more common single colon case a command sequence may be associated with at most one dependency line If the target is out of date with any of the dependents on any of the lines and a command sequence is specified even a null one following a semicolon or tab it is executed otherwise a default rule may be invoked In the double colon case a comma
333. nly will you have to enter a path name on the cc command line every time you use sharedob in a program that path name will be hard coded in your executables The reason why you want to avoid this is related to our next point We said that the command line cc L dir filel c file2 c file3 c lfoo Link Editor and Linking would direct the link editor to record in your executable the name of the shared object with which it is to be linked at run time Note the name of the shared object not its path name What this means is that when you use the 1 option to link your program with a shared object library not only must the link editor be told which directory to search for that library so must the dynamic linker unless the directory is the standard place which the dynamic linker searches by default We ll show you how to point the dynamic linker to directories in the subsection Specifying Directories to Be Searched by the Dynamic Linker on page 4 15 What we want to stress here is that as long as the path name of a shared object is not hard coded in your executable you can move the shared object to a different directory without breaking your program That s the main reason why you should avoid using path names of shared objects on the cc command line Those path names will be hard coded in your executable They won t be if you use 1 Finally the cc Zlink so command will not only create a shared object it will accept a shared objec
334. nment on page 9 2 Command Line Syntax for Editors 9 18 cscope invokes the vi editor by default You may override the default setting by assigning your preferred editor to the EDITOR environment variable and exporting EDITOR as described in the section Step 1 Set Up the Environment on page 9 2 Note however that cscope expects the editor it uses to have a command line syntax of the form editor linenum filename as does vi If the editor you want to use does not have this command line syntax you must write an interface between cscope and the editor Browsing Through Your Code with cscope Suppose you want to use ed for example Because ed does not allow specification of a line number on the command line you will not be able to use it to view or edit files with cscope unless you write a shell script called myedit here that contains the following line usr bin ed 2 Now set the value of EDITOR to your shell script and export EDITOR EDITOR myedit export EDITOR When cscope invokes the editor for the list item you have specified for example line 17 in main c it will invoke your shell script with the command line myedit 17 main c myedit will discard the line number 1 and call ed correctly with the file name 2 You will then have to execute the appropriate ed commands to display and edit the line because you will not be moved automatically to line 17 of the file 9 19 Compilation Systems V
335. nsiderably more complicated than simply incrementing a counter In all cases you declare the counters and other necessary variables in the definitions section commencing the lex specification The lex definitions section may contain any of several classes of items The most critical are external definitions preprocessor statements like include and abbreviations Recall that for valid lex source this section is optional but in most cases some of these items are necessary Preprocessor statements and C source code should appear between a line of the form and one of the form All lines between these delimiters including those that begin with white space are copied to lex yy c immediately before the definition of yylex Lines in the definition section that are not enclosed by the delimiters are copied to the same place provided they begin with white space The definitions section is where you would normally place C definitions of objects accessed by actions in the rules section or by routines with external linkage One example occurs in using lex with yacc which generates parsers that call a lexical analyzer In this context you should include the file y tab h which may contain defines for token names include y tab h extern int tokval int lineno After the that ends your include s and declarations you place your abbreviations for regular expressions to be used in the rules section The abbreviation appe
336. nsistently The parameter types in a function prototype declaration or definition differed from their types in another declaration or definition The message described after this one is issued for uses not declarations or definitions of a prototype with the wrong parameter types filei3a c 1 int funl int 2 int un2 int 3 int fun3 int file i3b c 1 int funl int i 2 int un2 int i 3 void foo 4 5 int AL 6 fun3 i 7 function argument number declared inconsistently fun2 arg 1 13b40 2 Int i3a c 2 int funl arg 1 i3a c 1 int i3b c 1 int function argument number used inconsistently fun3 arg 1 i3a c 3 int 13b2c 6y ant function argument number Format Compound The argument types used inconsistently in a function call did not match the types of the formal parameters in the function definition And see the discussion of the preceding message 10 20 Analyzing Your Code with lint file 1 c 1 int fun int x int y 2 3 return x y 4 file 2 c 1 int main 2 3 int x 4 extern int fun 5 return fun 1 x 6 function argument number used inconsistently fun arg 2 ficot2 y int si E205 aint function argument type inconsistent with format Format Compound An argument was inconsistent with the corresponding conversion specification in the control string of a fs printf or fs scanf function call See also PRINTFLIKEn
337. nt If the d flag is present in the file the SID is interpreted as if specified on the command line Thus one of the other cases in this figure applies R 1 the third entry in the right most column is used to force the creation of the first delta in a new release hR the seventh entry in the fourth column is the highest existing release that is lower than the specified nonexistent release R Table 14 1 Determination of New SID SID b Key Other SID SID of Delta Specified Letter Conditions Retrieved To be Created in get Used by get by delta none no R defaults to mR mR mL mR mL 1 none yes R defaults to mR mR mL mR mL mB 1 1 R no R gt mR mR mL R 1 14 14 Tracking Versions with SCCS Table 14 1 Determination of New SID Cont SID b Key Other SID SID of Delta Specified Letter Conditions Retrieved To be Created in get Used by get by delta R no R mR mR mL mR mL 1 R yes R gt mR mR mL mR mL mB 1 1 R yes R mR mR mL mR mL mB 1 1 R R lt mR and R hR mL hR mL mB 1 1 does not exist R Trunk successor R mL R mL mB 1 1 number in release gt R and R exists R L no No trunk R L R L 1 successor R L yes No trunk R L R L mB 1 1 successor R L Trunk successor R L R L mB 1 1 in release R R L B no No branch R L B mS R L B mS 1 successor R L B yes No branch R L B mS R L mB 1 1 successor R L B S no No branch R L B S R L B S 1 successor R L B S yes No branch R L B S
338. ntax discussions the following apply All entries in constant width all colons semicolons equal signs and at signs are typed in literally All entries in italics are substitutables e means zero or more e means one or more e means optional e seciion names and segment names follow the same rules as C identifiers where a period is treated as a letter e g bss is a legal name section names segment names file names and symbol names are case sensitive everything else is not case sensitive Spaces or new lines may appear anywhere except before a number or in the middle of a name or value Comments beginning with 4 and ending at a new line may appear any where that a space may appear A segment declaration creates a new segment in the a out or changes the attribute values of an existing segment An existing segment is one that you previously defined or one of the three built in segments described below A segment declaration has the following syntax segment name segment attribute value For each segment name you can specify any number of segment attribute values in any order each separated by a space Only one attribute value is allowed for each segment attribute The segment attributes and their valid values are as follows segment type LOA NOT HU segment flags R W X virtual address Vnumber ph
339. ntry is the one containing the login name of the user executing delta because the user who retrieved the g file must be the one who creates the delta However if the login name of the user appears in more than one entry the same user has executed get e more than once on the same SCCS file Then delta r must be used to specify the SID that uniquely identifies the p file entry This entry is then the one used to obtain the SID of the delta to be created In practice the most common use of delta is delta s abc which prompts comments to which the user replies with a description of why the delta is being made ending the reply with a new line character The user s response may be up to 512 characters long with new lines not intended to terminate the response escaped by backslashes If the SCCS file has a v flag delta first prompts with MRS 14 17 Compilation Systems Volume 1 Tools 14 18 Modification Requests on the standard output The standard input is then read for MR numbers separated by blanks and or tabs ended with a new line character A Modification Request is a formal way of asking for a correction or enhancement to the file In some controlled environments where changes to source files are tracked deltas are permitted only when initiated by a trouble report change request trouble ticket and so on collectively called MRs Recording MR numbers within deltas is a way of enforcing the rules of the change ma
340. number within the given release Thus the above command might output Died 213 lines If the given release does not exist get retrieves the trunk delta with the highest level number within the highest numbered existing release that is lower than the given release For example assume release 9 does not exist in file s abc and release 7 is the highest numbered release below 9 Executing get r9 s abc would produce 7 6 420 lines which indicates that trunk delta 7 6 is the latest version of file s abc below release 9 Similarly omitting the sequence number as in get r4 3 2 s abc results in the retrieval of the branch delta with the highest sequence number on the given branch This might result in the following output 4 3 2 8 89 lines If the given branch does not exist an error message results get t will retrieve the latest top version of a particular release when no r is used or when its value is simply a release number The latest version is the delta produced most recently independent of its location on the SCCS file tree Thus if the most recent delta in release 3 is 3 5 get r3 t s abc 14 11 Compilation Systems Volume 1 Tools To Update Source 14 12 would produce 345 59 lines However if branch delta 3 2 1 5 were the latest delta created after delta 3 5 the same command might produce Dios dog 46 lines get e indicates an intent to make a delta First get checks the following
341. o projlib up to date The internal rules are already defined to complete the preceding library maintenance The actual c a rule is as follows 13 11 Compilation Systems Volume 1 Tools CC c S CFLAGS lt S AR S ARFLAGS lt F c 0 rm f lt F c 0 Thus the 8 macro is the a target projlib the lt and macros are set to the out of date C language file and the file name minus the suffix respectively pfilel c and pfilel The lt macro in the preceding rule could have been changed to c It is useful to go into some detail about exactly what make does when it sees the construction projlib projlib pfilel o echo projlib up to date Assume the object in the library is out of date with respect to pfilel c Also there is no pfilel o file 1 make projlib 2 Before makeing projlib check each dependent of pro jlib 3 projlib pfilel o is a dependent of projlib and needs to be generated 4 Before generating projlib pfilel o check each dependent of projlib pfilel o There are none 5 Use internal rules to try to create projlib pfilel o There is no explicit rule Note that projlib pfilel o has a parenthesis in the name to identify the target suffix as a This is the key There is no explicit a at the end of the projlib library name The parenthesis implies the a suffix In this sense the a is hard wired into make 6 Break the name projlib pfilel o up into projlib and pfil
342. o symbols to definitions that are available 1d will issue warnings for undefined symbols unless z defs overrides Normally references to global symbols within shared objects are not bound until run time even if definitions are available so that I name L path M mapfile O args QAda QABI Link Editor and Linking definitions of the same symbol in an executable or other shared objects can override the object s own definition In dynamic mode only produce a shared object Undefined symbols are allowed unless the z defs option is specified When building an executable use name as the path name of the interpreter to be written into the program header The default in static mode is no interpreter in dynamic mode the default is the name of the dynamic linker usr lib libc so 1 Either case may be overridden by I exec will load this interpreter when it loads a out and will pass control to the interpreter rather than to a out directly Add path to the library search directories 1d searches for libraries first in any directories specified with L options then in the standard directories This option is effective only if it precedes the 1 option on the command line Read mapfile as a text file of directives to 1d Because these directives change the shape of the output file created by 1d use of this option is strongly discouraged Invoke the analyze 1 tool to perform a static performance analysis
343. o the previous example If the text of the initial delta does not contain ID keywords the message No id keywords cm7 14 19 Compilation Systems Volume 1 Tools is issued by admin as a warning However if the command also sets the i flag not to be confused with the i key letter the message is treated as an error and the SCCS file is not created Only one SCCS file may be created at a time using admin i admin r is used to specify a release number for the first delta Thus admin ifirst r3 s abc means the first delta should be named 3 1 rather than the normal 1 1 Because r has meaning only when creating the first delta its use is permitted only with i Inserting Commentary for the Initial Delta When an SCCS file is created the user may want to record why this was done Comments admin y and or MR numbers m can be entered in exactly the same way as with delta If y is omitted a comment line of the form date and time created YYMM DD HH MM SS by logname is automatically generated If it is desired to supply MR numbers admin m the v flag must be set with The v flag simply determines whether MR numbers must be supplied when using any SCCS command that modifies a delta commentary in the SCCS file see sccsfile 4 An example would be admin ifirst mmrnuml fv s abc Note that y and m are effective only if a new SCCS file is being created Initialization and Modification of SCCS File Par
344. oc 9 8 Screen 9 8 Viewing dispinit in the Editor llle eee eese 9 9 xxi Compilation Systems Volume 1 Tools Tables xxii Screen 9 9 Using cscope to Fix the Problem 0 0 00 000 0008 9 10 Screen 9 10 Changing a Text String 0 0 0 eee eee 9 14 Screen 9 11 cscope Prompts for Lines to Be Changed 2 2 22 9 15 Screen 9 12 Marking Lines to Be Changed 000000008 9 16 Screen 9 13 cscope Displays Changed Lines of Text o oooooooooocmoooo 9 16 Screen 9 14 Escaping from cscope to the Shell o ooooo ooooooooo o 9 17 Screen 11 1 Sample Output from analyze 11 2 Screen 13 1 make Internal Rules eee 13 20 Table 1 1 Compilers and Utilities 0 0 eee 1 4 Table 2 1 Available Directives 0 0 eee eee ee 2 19 Table 3 1 PowerPC Instruction Set 0 0 0 eee eee 3 2 Table 3 2 Condition Codes CC 0 ccc eee ees 3 25 Table 3 3 Trap Operand TO 0 0 00 cee eee eee 3 26 Table 3 4 Operand Abbreviations 0 0 0 eee 3 26 Table 3 5 Special Purpose Registers 00 0 0 cece eee eee ee 3 28 Table 3 6 Time Base Registers 0 0 eee eee eee eee 3 31 Table 3 7 Implementation Specific and Optional Instructions 3 31 Table 6 1 lex Operators seess eee teens 6 6 Table 9 1 Menu Manipulation Commands 0 0 0 0 00 eee eee 9 3 Table 9 2 Commands
345. of struct cmd Om aspe main S mymalloc unsigned strlen reffile strlen home 2 9 more lines press the space bar to display more Find this C symbol Find this global definition Find functions called by this function Find functions calling this function Find this text string Change this text string Find this egrep pattern Find this file Find files including this file Screen 9 7 cscope Lists Functions That Call mymalloc Because you know that the error message out of storage is generated at the beginning of the program you can guess that the problem may have occurred in the func tion dispinit display initialization To view dispinit the seventh function on the list type 7 Browsing Through Your Code with cscope void dispinit calculate the maximum displayed reference lines lastdispline FLDLINE 4 mdisprefs lastdispline REFLINE 1 AE mAisprefs gt I mdisprefs 9 allocate the displayed line array displine int mymalloc mdisprefs sizeof int L display a page of the references void display char file PATHLEN 1 file name char function PATLEN 1 function name char linenum NUMLEN 1 line number int screenline screen line number int width source line display width register int abr aa display c 622 lines 14326 characters Screen 9 8 Viewing dispinit in the Editor mymalloc f
346. of how many of the data are needed If an application uses only a small portion of a shared library s text and data executing the application might require more memory with a shared object than without one It would be unwise for example to use the standard C shared object library to access only strcmp Although sharing strcmp saves space on your disk and memory on 4 17 Compilation Systems Volume 1 Tools the system the memory cost to your process of having a private copy of the C library s data segment would make the archive version of st rcmp the more appropriate choice Now let s consider dynamic linking in a bit more detail First each process that uses a shared object references a single copy of its code in memory That means that when other users on your system call a function in a shared object library the entire contents of that library are mapped into the virtual address space of their processes as well If they have called the same function as you external references to the function in their programs will in all likelihood be assigned different virtual addresses That is because the function may be loaded at a different virtual address for each process that uses it the system cannot calculate absolute addresses in memory until run time Second the memory management scheme underlying dynamic linking shares memory among processes at the granularity of a page Memory pages can be shared as long as they are not mo
347. olume 1 Tools 9 20 10 Analyzing Your Code with lint Introduction told Ma oe ead set een a e 10 1 Options and Directives 0 02 cee eee 10 1 lint and the Compiler 0 0 0 cee II 10 2 M ss ge Formats 2e aan GR re TR xut RS 10 2 WbatlintDOes c eR RW RERO a UH ER Ies 10 2 Consistency Checks eee ek eR Etude ee Reg 10 2 Portability Checks sseeeeeeeeeeee I 10 3 Suspicious Constructs sse cee ee eee RR e ehh 10 5 MSA Bsr A re REPE ee 10 6 lint Libres tant a ect en ten 10 7 lint Filters nass seen ea RR Se whey 10 8 Options and Directives Listed o ooooooooocoococorcr rennen 10 8 lint specific Messages osse e sn e eae 10 12 argument unused in function 0 0 0 0 eee es 10 13 array subscript cannot be gt value value 00 0 0 eee ee eee 10 13 array subscript cannot be negative value eee esee 10 13 assignment causes implicit narrowing conversion 00 5 10 14 assignment of negative constant to unsigned type 08 10 14 assignment operator found where was expected 10 14 bitwise operation on signed value nonportable l l esee 10 15 constant in conditional context llle eee 10 16 constant operand to op Ud Loco 10 16 constant truncated by assignment 0 0 eee 10 16 conversion of pointer loses bits lene 10 17 conversion to larger integral type may sign extend incorrectly
348. on 2 5 e ee hea ead este ee enh Beat 9 1 How cscope Works conocio cick dies kes Mpe acia 9 1 How to Use scope cio a Son eis ened coe UR Ee CR eese 9 1 Step 1 Set Up the Environment 0 0 00 cee eee eee 9 2 Step 2 INVOKE scop un en ere REIR en 9 2 Step 3 Locate the Code iue a RR ke 9 3 Step 4 Edit the Code 05 cc eee ee ce cece cee eee renee es 9 9 Command Line Options 0 0 0 e cee cee eee eee 9 10 Using Viewpaths aci er dns ag Snead 9 13 Stacking cscope and Editor Calls eee 9 14 Examples cua a eo ed bee ee 9 14 Changing a Constant to a Preprocessor Symbol 9 14 Adding an Argument to a Function eese 9 17 Changing the Value of a Variable oooooooooomomomooo 9 18 Technical TIPS ico cess eet e Dae DR RIDERE eae eb 9 18 Unknown Terminal Type 0 0 cee I 9 18 Command Line Syntax for Editors 00 000 eese 9 18 Compilation Systems Volume 1 Tools Introduction 9 Browsing Through Your Code with cscope The cscope browser is an interactive program that locates specified elements of code in C lex or yacc source files It lets you search and edit your source files more efficiently than you could with a typical editor cscope has this capability because it can identify function calls and C language identifiers and keywords This chapter contains a tutorial on the cscope browser How cscope Works When you invoke cscope for a set of C lex
349. on instructs escope not to update the symbol cross reference You can use it to save time cscope will not check the source files for changes if you are sure that no such changes have been made NOTE Use the d option with care If you specify d under the erroneous impression that your source files have not been changed cscope will refer to an outdated symbol cross reference in responding to your queries To use cscope separately on several programs in the same directory structure while keep ing the databases in the same directory use the f and i options to rename the cscope out and cscope files file as follows find dirl name chlyCGHL print gt dirl files find dir2 name chlyCGHL print gt dir2 files cscope b f dirl db i dirl files cscope b f dir2 db i dir2 files Call cscope with cscope d f dir2 db Options used only when building the database such as i are not needed with the d option Use the P option to give the path to relative file names so the script does not have to change to the directory where the database was built The Ffile option reads symbol reference lines from file similar to the lt command Browsing Through Your Code with cscope The q option builds an inverted index for quick symbol searching If you use this option with the option you must use on every call to cscope including building the data base because it changes the names of the inverted index
350. on names section names 22 18 object files section types section types 22 12 object files segment types segment types 22 36 Object files string table string table 22 22 object files symbol table symbol table 22 23 Object files zero page zero page 22 21 22 22 Optimization during post linking stage 20 25 longjmp routine 20 25 setjmp routine 20 25 Optimization of constraints 20 10 20 27 20 28 20 29 Optimization programming techniques 20 30 20 31 20 32 Coding tips 20 30 20 31 Performance analysis techniques 20 30 20 32 Optimizations Safe Safe 20 2 Optimizations Unsafe Unsafe 20 2 Optimize 1 2 Optimizer 1 4 Options O 20 2 Q 20 13 20 15 20 18 20 20 20 22 Ordering identifier 1 5 Other security functions 16 52 Output Functions 16 9 paging 4 18 4 20 4 21 22 42 PARALLEL environment variable 13 5 13 17 Parameter functions 16 45 parser see yacc 1 7 1 Password File Access 16 13 16 14 16 15 16 16 Password file functions 16 14 petolf 1 1 5 Performance analysis 11 1 Performance analyzer 1 4 Pipe and FIFO functions 16 12 portability lint 1 checks for 10 3 10 5 position independent code 4 18 22 45 22 54 POSIX timer functions 16 35 Post Linker Optimization 20 25 PowerPC condition codes 3 25 implementation specific instructions 3 31 operand abbreviations 3 26 optional instructions 3 31 special purpose registers 3 28 time base registers 3 31 trap operand 3 26 PowerPC instructions 3 1 Precprocessor macro 1
351. only Supervisor Level Same as mtspr 991 rS mtsia IS Move To Sampled Instruction Address Register 604 e 620 only Supervisor Level Same as mtspr 955 rS mtsp IS Move To Single Precision Tag Register 602 only Supervisor Level Same as mtspr 1021 rS mtspr SPR 1S Move To Special Purpose Register 5 Supervisor Level if SPR 0 1 mtsprg n r Move to Special Purpose Register General n Supervisor Level Same as mtspr 272 n rS mtsr SR rS Move To Segment Register Supervisor Level mtsrd SR rS Move Doubleword To Segment Register Supervisor Level mtsrdin or 1S rB Move Doubleword To Segment Register Indirect mtsrind Supervisor Level mtsrin rS rB Move To Segment Register Indirect mtsri Supervisor Level mtsrrO IS Move to Save Restore Register 0 Supervisor Level Same as mtspr 26 rS mtsrr1 IS Move to Save Restore Register 1 Supervisor Level Same as mtspr 27 rS mttb IS Move to Time Base lower not on 601 Supervisor Level Same as mtspr 284 78 mttbl IS Move to Time Base Lower not on 601 64 bit Supervisor Level Same as mtspr 284 rS 3 19 Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC RS 6000 Syntax of Operands Description POWER Mnemonic Mnemonic mttbu IS Move to Time Base Upper not on 601 64 bit Supervisor Level Same as mtspr 285 rS mttcr IS Move To Time Control Register 602 only Supervisor Level Same as mtspr 984 rS mtthrm1 rS Move To Thermal 1 750 only Supervi
352. option above can be used to change this behavior Print a summary of all data sets to the specified file Print the raw statistics information from the profile data file in a human readable form Y character Z Specify a character which is used to enclose all routine names output in reports This is for an Ada filter that translates raw routine names into Ada R M expanded names Print information about blocks and routines that are executed zero times If no blocks in a routine were executed only the routine name is printed and the individual blocks for that routine are not reported For routines in which some blocks were executed and some were not the blocks with zero execution time are reported individually Z character Specify a character which is used to enclose all source file names output in reports This is for an Ada filter that translates raw source file names into actual file names 11 11 Compilation Systems Volume I Tools Assumptions and Constraints 11 12 The cycle counts reported are based on the cycle counts calculated by analyze and are subject to the same limitations described in the documentation for that tool Most notably the behavior of the memory system is not taken into account so actual wall time may be even longer than the maximum time reported especially if the application has many cache misses If the program was not compiled with line number information or if it was stripped before
353. or and Linking describes the 1d link editor and static and dynamic linking of relocatable object files and libraries including relocatable archives and shared objects For information about compressing common object files see cprs 1 Chapter 5 m4 Macro Processor discusses preprocessing C RATFOR assembly language and other source files with built in and user defined m4 macros For information about the C preprocessor see cpp 1 and acpp 1 Chapter 6 Lexical Analysis with lex describes how to write specifications for lex to separate and possibly generate statistics for components of program input Chapter 7 Parsing with yacc explains how to write grammar rules for yace so that it can act upon identified components of program input The following sections describe compilation systems Programming Languages Programming languages are used for specifying instructions and operations which are to be performed by programs running on a computer system Like the spoken languages that all human beings use each programming language has a grammar and a set of syntactic and semantic rules 1 See the Preface for details 1 1 Compilation Systems Volume 1 Tools There are hundreds of programming languages available to the computing world Concur rent Computer Corporation supports a few of the most popular languages C See the Concurrent C Reference Manual Fortran See the hf77 Fortran Reference Manual
354. ore than one segment type segment flags virtual address physical address length or alignment value appears on a single declaration line You attempt to manipulate either the interp segment or dynamic segment in a mapfile NOTE The interp and dynamic segments are special built in segments that you cannot change in any way A segment grows larger than the size specified by your length attribute value A user defined virtual address value causes a segment to overlap the previous segment More than one section name section type or section flags value appears on a single directive line A flag and its complement e g A and A appear on a single directive line Quick Reference Guide 1 By convention shared objects or dynamically linked libraries are designated by the prefix lib and the suffix so archives or statically linked libraries are designated by the prefix lib and the suffix a libc so then is the shared object version of the standard C library libc a is the archive version These conventions are recognized in turn by the 1 option to the ce command That is 1x directs the link editor to search the shared object libx so or the archive library libx a The cc command automatically passes lc to the link editor In other words the compilation system arranges for the standard C library to be linked with your program transparently By default the link editor chooses the shared object implementation
355. ore the character Now move the cursor to the fifth menu item Find this text string enter the text out of storage and press the RETURN key cscope Press the key for help Find Find Find Find Find BRE SACIS Vinos this global definition functions called by this function functions calling this function this text string out of storage Change this text string Find Find Find this egrep pattern this file files including this file Screen 9 2 Requesting a Search for a Text String NOTE Follow the same procedure to perform any other task listed in the menu except the sixth Change this text string Because this task is slightly more complex than the others there is a different procedure for performing it For a description of how to change a text string see Examples on page 9 14 cscope searches for the specified text finds one line that contains it and reports its finding as follows Text string Browsing Through Your Code with cscope out of storage File Line 1 alloc c 63 void fprintf stderr n s out of storage n argv0 band ENES Es ymbol Find this global definition Find functions called by this function bandekunetienss calling this Funeteron Find this text string Change this text string Find this egrep pattern Find this file Find files including this file Screen 9 3 cscope Lists Lines Containing the Text String After cscope shows you the results of
356. ot Then use the less frequently called functions as glue between the chunks Because the glue between pages is referenced less frequently than the page contents the probability of a page fault is decreased You can put frequently used unrelated functions together because they will probably be called randomly enough to keep the pages in memory Avoid hardware thrashing You get better performance by arranging the typical process to avoid cache entry conflicts If a heavily used library had both its text and its data segments mapped to the same cache entry the performance penalty would be particularly severe Every library instruction would bring the text segment information into the cache Instructions that referenced data would flush the entry to load the data segment Of course the next instruction would reference text and flush the cache entry again Now let s look at some maintenance issues We have already seen how allocating buffers dynamically can ease the job of library maintenance As a general rule you want to be sure that updated versions of a shared object are compatible with its previous versions so that users will not have to recompile their applications At the very least you should avoid changing the names of library symbols from one release to the next All the same there may be instances in which you need to release a library version that is incompatible with its predecessor On the one hand you will want to maintain the ol
357. ough to allow a programmer to define a makefile or set of makefiles whose parameters are dynamically definable Suggestions and Warnings Internal Rules The most common difficulties arise from make s specific meaning of dependency If file x chasa include defs h line then the object file x o depends on defs h the source file x c does not If defs h is changed nothing is done to the file x c while file x o must be recreated To discover what make would do the n option is very useful The command make n orders make to print out the commands that make would issue without actually taking the time to execute them If a change to a file is absolutely certain to be mild in character adding a comment to an include file for example the t touch option can save a lot of time Instead of issuing a large number of superfluous recompilations make updates the modification times on the affected file Thus the command make ts touch silently causes the relevant files to appear up to date Obvious care is necessary because this mode of operation subverts the intention of make and destroys all memory of the previous relationships The standard set of internal rules used by make are reproduced below 13 19 Compilation Systems Volume 1 Tools SUFFIXES RECOGNIZED BY MAKE SUBE DA IS xe el PREDEFINED MACROS AR ar ARFLAGS rv AS as ASFLAGS BUILD build CC cc CFLAGS 0 C C CC C FLAGS 0 F77 77 FFLAGS
358. oup IDs of users who are allowed to modify the file by adding or removing deltas Flags indicators that control certain actions of SCCS commands 14 27 Compilation Systems Volume 1 Tools Auditing 14 28 Descriptive Text usually a summary of the contents and purpose of the file Body the text administered by SCCS intermixed with internal SCCS control lines Details on these file sections may be found in secsfile 4 The checksum line is discussed in Auditing on page 14 28 Because SCCS files are ASCII files they can be processed by non SCCS commands like ed grep and cat This is convenient when an SCCS file must be modified manually a delta s time and date were recorded incorrectly for example because the system clock was set incorrectly or when a user wants simply to look at the file CAUTION Extreme care should be exercised when modifying SCCS files with non SCCS commands When a system or hardware malfunction destroys an SCCS file any command will issue an error message Commands also use the checksum stored in an SCCS file to determine whether the file has been corrupted because it was last accessed possibly by having lost one or more blocks or by having been modified with ed No SCCS command will process a corrupted SCCS file except the admin h or z as described below SCCS files should be audited for possible corruptions on a regular basis The simplest and fastest way to do an audit is to use admin
359. ource files in the current directory and for any included header files in the current directory or the standard place If all the source files for the program to be browsed are in the current directory and if its header files are there or in the standard place invoke cscope without arguments cscope To browse through selected source files invoke cscope with the names of those files as arguments cscope filel c file2 c file3 h For other ways to invoke cscope see Command Line Options on page 9 10 cscope builds the symbol cross reference table the first time it is used on the source files for the program to be browsed By default the table is stored in the file cscope out in the current directory On a subsequent invocation escope rebuilds the cross reference only if a source file has been modified or the list of source files is differ ent When the cross reference is rebuilt the data for the unchanged files are copied from the old cross reference which makes rebuilding faster than the initial build and startup time less for subsequent invocations Browsing Through Your Code with cscope Step 3 Locate the Code Now you can begin to identify the problem that is causing the error message out of storage to be printed You have invoked escope and the cross reference table has been built The cscope menu of tasks appears on the screen cscope Press the key for help Find Find Find Find Find this C symbol this global
360. p ee een ERE SV Pe s 13 6 Dependency Information sleeeeee eh 13 7 Executable Commands anann ccc ccc cece ee a 13 7 Extensions of and 4 lesse eas 13 8 Output Translations e i e a II 13 8 Recursive Makefiles ici DE eoe Beer EUN ES 13 8 Suffixes and Transformation Rules oooooooooooooooooo 13 9 Implicit Rules use OACI OP ATS ERs NUT edes 13 9 Archive Libraries io 13 11 Source Code Control System File Names 0 000000 ooo 13 13 The Null Sufix 3st dor ote SRS sn 13 13 Included Files ies A ew Sete a SR RADO ee ee S 13 14 SCCS Maketiles ui A EX Nue ETC DES 13 14 Dynamic Dependency Parameters o ooooooococcococor eese 13 14 Viewpaths VPATH 2 0 cece ce hh mmm 13 15 Command Usate s eue nenne IS en 13 16 The make Command 0 0 0 ccc ee ls 13 16 Environment Variables oooooooooooo ooo 13 18 Suggestions and Warnings 1 0 0 0 eee eee eee eee eee 13 19 Internal RUE A Bees a A A OEE I SU 13 19 Chapter 14 Tracking Versions with SCCS Introduction en sanae en aa A eS GAs 14 1 Basic Usage c sists A dele honda epit ean eaa t e 14 1 T rminolo8y x A SENT NAT SEES E 14 1 Creating an SCCS File with admin 0 00 0 002 ee eee 14 2 Retrieving a File with get 14 2 Recording Changes with delta lees 14 3 More OIL Betas uno A e MERE SEES ER 14 4 The help Command u Rene place ee en 14 5 Contents
361. perations file file file The quoted string file is placed in the object file s symbol table The leading and the terminating double quotes are not assembled and the string is not appended with a trailing null byte 0 file is of length 1 255 characters inclusive If the assembler A option is used however file may be of length 1 800 characters inclusive Only one file directive may be specified in an assembly file If the A option is used however multiple file directives may be specified For example file source c place the file name source c in the symbol table ident s ring string is assembled into the comment section It is regarded as a C style string The leading and the terminating double quotes are not assembled and the string is 2 18 Assembler and Assembly Language appended with a trailing null byte 10 This directive is typically used to provide revision level tracking information For example ident revision 5 1 3 place the string in the comment section fp spec exec This directive indicates that the assembly code contains floating point instructions that are executed in a speculative manner See the discussion of speculative execution in Chapter 20 Modules that speculatively execute floating point instructions could erroneously raise floating point exceptions making it necessary to link programs with all floating point exceptions disabled See the discussion of the
362. piler writer might place in the user routines section of the parser Second in the last few actions of the example tokval is assigned a specific integer indicating which arithmetic or relational operator the scanner recognized If the variable PLUS for instance is associated with the integer 7 by means of the define statement above then when a is recognized the action assigns to tokval the value 7 which indicates the The scanner indicates the general class of operator by the value it returns to the parser that is the integer signified by ARITHOP or RELOP In using lex with yacc either may be run first The command yacc d grammar y generates a parser in the file y tab c As noted the d option creates the file y tab h which contains the define statements that associate the yacc assigned integer token values with the user defined token names Now you can invoke lex with the command lex lex 1 then compile and link the output files with the command cc lex yy c y tab c ly 11 Note that the yacc library is loaded via 1y before the lex library via 11 to ensure that the supplied main will call the yace parser Miscellaneous Recognition of expressions in an input text is performed by a deterministic finite automaton generated by lex The v option prints out for you a small set of statistics describing the finite automaton For a detailed account of finite automata and their importance for lex see the Aho Se
363. portion or the exponent may be omitted but not both The exponent consists of e or i optionally signed integer For example 4 3 25 4367e 10 0f 15 E followed by an Assembler and Assembly Language Character Constants Expressions A single character constant consists of a single quote followed by an ASCII character other than backslash The value of the constant is the ASCII code for the character Special meanings of characters are overridden when used in character constants For example and represent the constants and respectively and do not represent a terminating followed by a comment A special character constant consists of followed by another character The special character constants are listed below Constant Value Meaning Nb 0x08 backspace ONE 0x09 horizontal tab An 0x0a newline line feed CAE 0x0c form feed UNT Ox0d carriage return EN Ox3f question mark AN 0x22 double quote i 0x27 single quote AN Ox5c backslash Nnnn Onnn octal character nnn Forexample q An 015 Expressions represent 32 bit two s complement values They are built up from symbols constants operators and parentheses Expressions have types which are discussed later in this section 2 9 Compilation Systems Volume 1 Tools Expression Operators The following operators are available Class Operator Function Comment binary addition subtraction multipli
364. ppear in list bold type Preface list Operating system and program output such as prompts and messages and listings of files and programs appears in list type Keywords also appear in list type emphasis Words or phrases that require extra emphasis use emphasis type window Keyboard sequences and window features such as push buttons radio buttons menu items labels and titles appear in window type Brackets enclose command options and arguments that are optional You do not type the brackets if you choose to specify such option or arguments 1 Braces enclose mutually exclusive choices separated by the pipe I character where one choice must be selected You do not type the braces or the pipe character with the choice An ellipsis follows an item that can be repeated The window images in this manual come from a Motif environment If you are using another environment your windows may differ slightly from those presented here Referenced Publications The following publications are referenced in this document 0890240 hf77 Fortran Reference Manual 0890288 HAPSE Reference Manual 0890395 NightView User s Guide 0890398 NightTrace Manual 0891019 Concurrent C Reference Manual The vendor publications referenced in this manual may be viewed on the respective s companies WWW site Compilation Systems Volume 1 Tools vi Contents Contents Part 1 Software Development Environments Chapter 1 Introduction to
365. processor 1 4 C programming language 1 2 Index 2 CC 1 creating shared objects 4 13 cc 1 1 4 creating shared objects 4 12 4 18 4 21 4 22 library linking option 4 9 4 16 4 35 library search option 4 16 4 36 static linking options 4 10 4 11 4 14 4 15 4 35 cc 1 4 13 CCG 1 3 cdc 1 14 9 14 24 cflow 1 1 5 Character Manipulation 16 22 16 25 16 26 Character test functions 16 25 Character Translation Functions 16 26 Character translation functions 16 26 Code checker C 1 5 Code motion 20 16 20 17 COFF 1 5 comb 1 14 9 14 25 14 26 comm directive 2 17 Comment 2 5 Common code generator 1 3 Common Object File Format 1 5 Common subexpression elimination 20 16 20 17 Compilation system 1 2 Compiler 1 2 Ada 1 4 C 1 4 Fortran 1 4 Compiler optimization classes 20 10 20 11 20 12 20 14 20 15 20 16 20 17 20 18 20 19 20 20 20 21 20 22 20 24 20 26 20 27 20 28 20 29 Branch optimizations 20 10 20 11 20 12 Expression optimizations 20 10 20 16 20 17 Inline expansion of subprograms 20 10 20 26 Instruction scheduling 20 10 20 24 Loop optimizations 20 10 20 18 20 19 20 20 20 21 20 22 Optimization of constraints 20 10 20 27 20 28 20 29 Register allocation 20 10 20 24 Variable optimizations 20 10 20 12 20 14 20 15 20 16 Compiler optimization levels 20 2 Compiler optimization options 20 2 O 20 2 Q 20 2 20 3 20 8 Compiler options Verbose Verbose 20 10 Compiler technology 20 1 Compiler compiler 1
366. program to exit When the P option is used this routine when called will dump the accumulated statistics to the prof file After writing the statistics data set to the prof file the statistics are reset to zero When the O option is used the X option will exclude the named routine from the optimization W routine weight a routine Specify a weighting factor for counting lis instructions in routine routine If weight is omitted it will default to 5 This option is used with the O option Add the specific named routine to the list of routines to be analyzed This can 11 5 Compilation Systems Volume I Tools 11 6 be used after N to add a routine to the list If used without N it assumes you meant to specify N and supplies one for you d file Generate a detailed disassembly listing of each routine included in the analysis The listing is done on a per basic block basis By default this only generates the assembler listing the clock cycle each instruction executes at relative to the beginning of each basic block and the reason any instruction is delayed Use the v option for more detail Use the CZstage status option for much more verbose status of each pipeline stage each cycle g file Generate global program statistics to file i Print various informative bits of information about the object file n Use nesting level to weight the count of 1is instructions This option is used with the
367. projlib entry_pt where the second method actually refers to an entry point of an object file within the library make looks through the library locates the entry point and translates it to the correct object file name To use this procedure to maintain an archive library the following type of makefile is required projlib projlib pfilel o S CC c S CFLAGS pfilel c S AR S ARFLAGS projlib pfilel o rm pfilel o pro lib projlib pfile2 o S CC c S CFLAGS pfile2 c S AR S ARFLAGS projlib pfile2 o rm pfile2 o and so on for each object This is tedious and error prone Obviously the command sequences for adding a C language file to a library are the same for each invocation the file name being the only difference each time This is true in most cases The make command also gives the user access to a rule for building libraries The handle for the rule is the a suffix Thus a c a rule is the rule for compiling a C language source file adding it to the library and removing the o file Similarly the y a the s a and the 1 a rules rebuild yacc assembler and lex files respectively The archive rules defined internally are c a c a f a f a and s a The tilde syntax will be described shortly The user may define other needed rules in the description file The above two member library is then maintained with the following shorter makefile projlib projlib pfilel o projlib pfile2 o ech
368. put Syntax cit te er ea sn cee Sees e 7 29 Examples 2 4 oerte erat e ini eun oed 7 30 1 A Simple Example ess e HERE I es 7 30 2 An Advanced Example 0 0 0 eee 7 33 Compilation Systems Volume 1 Tools 7 Parsing with yacc Introduction yacc provides a general tool for imposing structure on the input to a computer program When you use yacc you prepare a specification that includes A set of rules to describe the elements of the input Code to be invoked when a rule is recognized e Either a definition or declaration of a low level scanner to examine the input yacc then turns the specification into a C language function that examines the input stream This function called a parser works by calling the low level scanner The scanner called a lexical analyzer picks up items from the input stream The selected items are known as tokens Tokens are compared to the input construct rules called grammar rules When one of the rules is recognized the code you have supplied for the rule is invoked This code is called an action Actions are fragments of C language code They can return values and make use of values returned by other actions The heart of the yace specification is the collection of grammar rules Each rule describes a construct and gives it a name For example one grammar rule might be date month name day year where date month name day and year represent constructs of interest pre
369. put corresponding to IF cond stat and the two grammar rules shown are active at this time The parser can do two possible things If the input symbol is ELSE it is possible to shift into state 45 State 45 will have as part of its description the line 7 15 Compilation Systems Volume 1 Tools Precedence 7 16 stat IF cond stat ELSE stat because the ELSE will have been shifted in this state In state 23 the alternative action specified by is to be done if the input symbol is not mentioned explicitly in the actions In this case if the input symbol is not ELSE the parser reduces to stat IF cond stat by grammar rule 18 Once again notice that the numbers following shift commands refer to other states while the numbers following reduce commands refer to grammar rule numbers In the y output file rule numbers are printed in parentheses after those rules that can be reduced In most states there is a reduce action possible and reduce is the default command If you encounter unexpected shift reduce conflicts you will probably want to look at the v output to decide whether the default actions are appropriate There is one common situation where the rules given above for resolving conflicts are not sufficient This is in the parsing of arithmetic expressions Most of the commonly used constructions for arithmetic expressions can be naturally described by t
370. put off until run time shared objects can be updated without having to relink applications that depend on them As long as its path name is not hard coded in an executable a shared object can be moved to a different directory without breaking an application Guidelines for Building Shared Objects 4 18 This subsection gives coding guidelines and maintenance tips for shared library development Before getting down to specifics we should emphasize that if you plan to develop a commercial shared library you ought to consider providing a compatible archive as well As we have noted some users may not find a shared library appropriate Link Editor and Linking for their applications Others may want their applications to run on PowerUX system releases without shared object support Shared object code is completely compatible with archive library code In other words you can use the same source files to build archive and shared object versions of a library Let s look at some performance issues first There are two things you want to do to enhance shared library performance Minimize the Library s Data Segment As noted only a shared object s text segment is shared by all processes that use it its data segment typically is not Every process that uses a shared object usually gets a private memory copy of its entire data segment regardless of how many of the data are needed You can cut down the size of the data segment a number of
371. quire the degree of flex ibility provided by the command language In fact it is usually best to allow the link editor to produce its own layout and perform its own allocation of program resources The detailed command language supports the ability to Specify the memory configuration of the program Combine object file sections in particular fashions Bind the files to specific addresses or portions of memory Define or redefine global symbols at link edit time Using the Link Editor The link editor is invoked as follows ld options files Files passed to the link editor are object files libraries containing object files or text source files containing 1d directives The link editor uses the magic number the first two bytes of the file to determine the file type The following options are recognized by 1d a In static mode only produce an executable object file give errors for undefined references This is the default behavior for static mode a may not be used with the r option 4 1 Compilation Systems Volume 1 Tools diyInj e epsym h name m o outfile E S In dynamic mode only when creating an executable do not do special processing for relocations that reference symbols in shared objects Without the b option the link editor will create special position independent relocations for references to functions defined in shared objects and will arrange for data objects d
372. r bss on line 3 The monkey segment is implicitly declared in line 2 with segment type value LOAD segment flags value RWX and no virtual address physical address length or alignment values specified defaults are used In line 4 the segment type value of monkey is set to LOAD since the segment type attribute value does not change no warning is issued virtual address value to 0x80000000 and maximum length value to 0x4000 since the length attribute value changed a warning is issued Line 5 implicitly declares the donkey segment The entrance criteria is designed to route all bss sections to this segment Actually no sections fall into this segment because the entrance criteria for monkey in line 3 capture all of these sections In line 6 the segment flags value is set to RX and the alignment value is set to 0x1000 since both of these attribute values changed a warning is issued Line 7 sets the virtual address value of the text segment to 0x80008000 no warning is issued here 4 29 Compilation Systems Volume 1 Tools The example user defined mapfile in Figure 4 1 is designed to cause warnings for illustration purposes If you wanted to change the order of the directives to avoid warnings the example would appear as follows LA elephant bss peanuts o popcorn o 4 monkey LOAD VOx80000000 L0x4000 23 monkey SPROGBITS AX 3 monkey bss 6 donkey RX A0x1000 Des donkey bss 7 text V0x8000800
373. r has been found In the latter cases the analyzer must also specify the exact value of the token what the identifier is whether the constant is say 9 or 888 whether the operator is or and whether the relational operator is or gt Consider the 6 15 Compilation Systems Volume I Tools following portion of lex source discussed in another context earlier for a scanner that recognizes tokens in a C like language begin return BEGIN end return END while return WHILE TE return IF package return PACKAGE reverse return REVERSE loop return LOOP a zA Z a zA 20 9 EOI put in tabl return IDENTIFIER 0 9 DECO put_in_tabl EO return TEO return to PLUS ARITHOP MINUS ARITHOP 1 GREATER return RELOP tokval GREATEREQL return RELOP a a return INTEGER a a a a Despite appearances the tokens returned and the values assigned to tokval are indeed integers Good programming style dictates that we use informative terms such as BEGIN END WHILE and so forth to signify the integers the parser understands rather than use the integers themselves You establish the association by using define statements in your parser calling routine in C For example define BEGIN 1 define END 2 define PLUS 7 If the need arises to change the integer for some token type
374. rPC 601 and 620 tbu Half word specifiers hil6 upper 16 bits of a relocatable expression for signed operations uhil6 upper 16 bits of a relocatable expression for unsigned operations 1016 lower 16 bits of a relocatable expression NOTE An instruction which uses 1016 as the half word specifier often has a corresponding instruction which provides the upper 16 bits of a relocatable expression If the instruction using 1016 performs a sign extension of the 16 bit operand then hi16 should be used in the corresponding instruction which provides the upper 16 bits otherwise uhil6 should be used in the corresponding instruction For example lis rs uhil6 x ori rs rs 1016 x but lis rs hil6 x addi rs rs 1lol16 x Branch instruction operands eq ne gt le lt ge so un ns z nl ng nz nu If the version 03 00 directive is specified in an assembly file the assembler requires that a leading be prefixed to the following predefinitions General register names Extended register names Control register names Half word specifiers Bit number mnemonics Match field mnemonics Compilation Systems Volume 1 Tools User Defined Symbols Constants The user may define a symbol in one of the following ways e Asa label The symbol s value is the value of the location counter where the label is defined e As a constant The def directive can be used to assign a 32 bit value to the symbol Refer to Symbo
375. rd C library libc aisthe archive version 2 These conventions are recognized in turn by the 1 option to the cc command That is cc filel c file2 c file3 c 1x directs the link editor to search the shared object libx so or the archive library libx a The cc command automatically passes Lc to the link editor 4 9 Compilation Systems Volume 1 Tools 3 By default the link editor chooses the shared object implementation of a library 1ibx so in preference to the archive library implementation libx a in the same directory 4 By default the link editor searches for libraries in the standard places on the system usr lib and lib in that order Adding it up we can say more exactly than before that the default ec command line will direct the link editor to search usr lib libc so rather than its archive library counterpart We ll look at each of the items that make up the default in more detail below libc so is with one exception the only shared object library supplied by the C compilation system The exception 1ibdl so is used with the programming interface to the dynamic linking mechanism described later Other shared object libraries are supplied with the operating system and usually are kept in the standard places In the next subsection we ll show you how to link your program with the archive version of libc to avoid the dynamic linking default Of course you can link your program with libraries that per
376. re is no restriction on the divisibility of the location counter when this directive is used The specified expression s are assembled into consecutive 4 byte locations Each expression is of absolute or relocatable type or is an undefined external Each expression is in the range 0 to 232 1 For example uaword 1078 457 108324 float float floatconst floatconst The location counter must be evenly divisible by 4 when this directive is used The specified floatconst s are assembled into consecutive 4 byte locations Each floatconst is in the range of IEEE single precision numbers For example float 3 1415 0 0 2 15 Compilation Systems Volume 1 Tools double double loatconst floatconst The location counter must be evenly divisible by 8 when this directive is used The specified floatconst s are assembled into consecutive 8 byte locations Each floatconst is in the range of IEEE double precision numbers For example double 1 5 2 34e31 string ascii string string The specified string s are assembled into consecutive locations one character of the string per byte The quoted string is regarded as a C style string The leading and the terminating double quotes are not assembled and the string is not appended with a trailing null byte 10 For example string several bytes asciiz string stringl The specified string s are assembled into consecutive locations one character of the
377. rectories are silently ignored In general file name arguments may not begin with a hyphen If a lone hyphen is specified the command will read the standard input usually your terminal for lines and take each line as the name of an SCCS file to be processed The standard input is read until end of file This feature is often used in pipelines Key letters are processed before file names so the placement of key letters is arbitrary they may be interspersed with file names File names however are processed left to right Somewhat different conventions apply to help what sccsdiff and val detailed later in SCCS Commands on page 14 8 Certain actions of various SCCS commands are controlled by flags appearing in SCCS files Some of these flags will be discussed but for a complete description see admin 1 14 7 Compilation Systems Volume 1 Tools The distinction between real user see passwd 1 and effective user will be of concern in discussing various actions of SCCS commands For now assume that the real and effective users are the same the person logged into the UNIX system x files and z files Error Messages All SCCS commands that modify an SCCS file do so by first writing and modifying a copy called x file This is done to ensure that the SCCS file is not damaged if processing terminates abnormally x file is created in the same directory as the SCCS file given the same mode see chmod 1 and is owne
378. register f0 f31 fS floating point register f0 f31 fT floating point register target f0 f31 FXM mask of CR fields 1 255 L precision of fixed point compare 0 1 LI 24 bit displacement label MB bit number of first bit of mask 0 31 ME bit number of last bit of mask 0 31 NB byte count 0 31 0 means 32 tA general register If italic then rA 0 means zero r0 r31 rB general register r0 r31 IS general register r0 r31 IT general register target r0 r31 SH shift amount 0 31 SI signed 16 bit integer 32768 32767 SPR special purpose register 0 1023 SR segment register 0 15 TBR time base register 268 269 TO trap conditions 0 31 U immediate value 0 15 UI unsigned 16 bit integer 0 65535 3 27 Compilation Systems Volume 1 Tools Special Purpose Registers 3 28 Table 3 5 Special Purpose Registers Number Name Description 0 MQ Multiply Quotient Register 601 only 1 XER Fixed Point Exception Register 4 RICU Real Time Clock Upper read only 601 only 5 RICL Real Time Clock Lower read only 601 only 6 DEC Decrementer 601 only This is identical to Special Register 22 8 LR Link Register 9 CTR Count Register 18 DSISR Data Storage Interrupt Status Register 19 DAR Data Address Register 20 RICU Real Time Clock Upper write only 601 only 21 RICL Real Time Clock Lower write only 601 only 22 DEC Decrementer 25 SDRI Storage Description Register 1 26 SRRO Save Restore Register 0 27 SR
379. right to left More seri ously an internal stack in the parser is in danger of overflowing if an extremely long sequence is read although yace can process very large stacks Thus you should use left recursion wherever reasonable It is worth considering if a sequence with zero elements has any meaning and if so consider writing the sequence specification as seq empty seq item 7 using an empty rule Once again the first rule would always be reduced exactly once before the first item was read and then the second rule would be reduced once for each item read Permitting empty sequences often leads to increased generality However conflicts might arise if yace is asked to decide which empty sequence it has seen when it hasn t seen enough to know Some lexical decisions depend on context For example the lexical analyzer might want to delete blanks normally but not within quoted strings or names might be entered into a symbol table in declarations but not in expressions One way of handling these situations is to create a global flag that is examined by the lexical analyzer and set by actions For example ipe dtrag other declarations empty dflag 1 decls declaration empty dflag 0 stats statement other rules specifies a program that consists of zero or more declarations followed by zero or more statements The flag dflag is now 0 when reading statements and 1 when reading declar
380. rimary data cache for use with the C option The cache size argument is the total primary data cache size It may be suffixed with M for megabytes or K for kilobytes A cache_size of 0 is not permitted The optional block_size argument is the cache block line size in bytes it defaults to 64 bytes The optional sets argument is the number of sets it defaults to cache_size divided by block_size For example Zpdcache 32k 32 128 specifies an 8 way associative primary data cache of size 32768 bytes with 128 sets each set containing 8 cache blocks 32 bytes long This option also indicates that the primary data cache is separate from the primary instruction cache therefore it may not be used with the Zpucache option If this option is not used the data cache characteristics are determined by the CPU type picache cache_size block_size sets Define the characteristics of the primary instruction cache for use with the C option The cache size argument is the total primary instruction cache size It may be suffixed with M for megabytes or K for kilobytes A cache size of 0 is not permitted The optional block_size argument is the cache block line size in bytes it defaults to 64 bytes The optional sets argument is the number of sets 1t defaults to cache_size divided by block_size For example Zpicache 32k 32 128 specifies an 8 way associative primary instruction cache of size 32768 bytes with 128 sets each 11 7 Compilation System
381. roduction Introduction to Analysis 8 Introduction to Analysis By using tools to analyze source files and executables you can Locate and correct problems Obtain statistics on usage and performance timings Improve program reliability and performance Many analysis tools exist See Concurrent Computer Corporation Compilation Systems section in Chapter 1 for an extensive list of these and other utilities Although not discussed in this manual the C beautifier cb 1 can assist in analysis it makes C source files more readable with judicious placement of spaces and indentation The xref 1 utility combines many cross referencing aspects of cscope and inconsistency detecting aspects of lint for Fortran source files See the man page for details This part of the manual discusses the analysis of source files and executables Chapter 9 Browsing Through Your Code with cscope discusses cross referencing searching and editing C lex and yace source files with cscope Chapter 10 Analyzing Your Code with lint describes using lint on C source files to flag inconsistent use non portable code and suspicious constructs Chapter 11 Performance Analysis explains how to use analyze to optimize programs or obtain performance profiles on programs and report to generate reports from analyze s output 8 1 Compilation Systems Volume 1 Tools 8 2 9 Browsing Through Your Code with cscope l troducti
382. rporation See the NightView User s Guide for details Symbolic ctrace 1 This utility displays source statements as they execute It also shows debugger variable names and values and any output from the statement Object adb 1 This debugger provided on some vendors UNIX systems allows a debugger program to be debugged at the instruction level Compiler yacc 1 This utility converts a context free grammar into a set of tables for a compiler simple automation which uses an LR 1 parsing algorithm Lexical lex 1 This utility generates simple code to be used in the lexical analysis of analyzer text input Introduction to SDEs Table 1 1 Compilers and Utilities Cont Type Name Description C code lint 1 This utility examines C source for syntax errors and incompatible checker routine interfaces C code cscope 1 This utility is used for browsing C source code for specified elements browser C cross refer ence generator Name lister Section manipulator Dumper Sizer Stripper Compressor Disassembler pc to line number and file name translator Macro preprocessor Ordering identifier C flow grapher Topological sorter cxref 1 nm 1 mcs 1 dump 1 size 1 strip 1 cprs 1 dis 1 pctolf 1 m4 1 lorder 1 cflow 1 tsort 1 This utility builds a cross reference table from C source files This utility is used to provide a readable display
383. rror recovery has been accomplished The statement yyerrok in an action resets the parser to its normal mode The last example can be rewritten as 7 21 Compilation Systems Volume 1 Tools input error An yyerrok void printf Reenter last line input 4 r As previously mentioned the token seen immediately after the error symbol is the input token at which the error was discovered Sometimes this is inappropriate for example an error recovery action might take upon itself the job of finding the correct place to resume input In this case the previous lookahead token must be cleared The statement yyclearin in an action will have this effect For example suppose the action after error were to call some sophisticated resynchronization routine supplied by the user that attempted to advance the input to the beginning of the next valid statement After this routine is called the next token returned by yylex is presumably the first token in a valid statement The old invalid token must be discarded and the error state reset A rule similar to stat error resynch yyerrok yyclearin could perform this These mechanisms are admittedly crude but do allow for a simple fairly effective recovery of the parser from many errors Moreover the user can get control to deal with the error actions required by other portions of the program The yacc Environment 7 22 You
384. s address space the remaining code and data needed by the program This additional code and data is provided by shared objects or shared libraries Introduction to SDEs Dynamically linked programs provide greater sharing of pages of memory and their on disk images are smaller than those of equivalent statically linked programs Statically linked programs however typically run faster than dynamically linked programs Floating Point Arithmetic The representation and operations of floating point numbers varies among computer systems The supporting hardware platforms uses the representation and operations specified by the JEEE Standard for Binary Floating Point Arithmetic which has become a de facto standard for floating point arithmetic Concurrent compilation systems support the single precision and the double precision formats No support is provided for the double extended precision format 1 7 Compilation Systems Volume 1 Tools 1 8 2 Assembler and Assembly Language Introduction ee MA o 2 1 Assembler Operation 0 0 pauca a a e aa e e eea E E rennen 2 1 Using the Assembler 0 0 2 0 0 E eee E EE E 2 2 Assembler Invoc ation ecce e eret De E eet eed 2 2 Character Set is po S ang oe Sack nk hace Deneck deg 2 4 So rce Statements rea die idee eger desees er eee ende ies 2 4 Null Statements ice 2 002000 RETE RAS RU 2 4 Alphanumeric Labels 0 0 ccc cece eh 2 4 Numeric Local Labels
385. s Volume I Tools 11 8 set containing 8 cache blocks 32 bytes long This option also indicates that the primary instruction cache is separate from the primary data cache therefore it may not be used with the Zpucache option If this option is not used the instruction cache characteristics are determined by the CPU type pucache cache_size block_size sets Define the characteristics of the unified primary cache for use with the C option The cache size argument is the total unified primary cache size It may be suffixed with M for megabytes or K for kilobytes A cache size of 0 is not permitted The optional block size argument is the cache block line size in bytes it defaults to 64 bytes The optional sets argument is the number of sets it defaults to cache size divided by block size For example Zpucache 32k 64 64 specifies an 8 way associative unified primary cache of size 32768 bytes with 64 sets each set containing 8 cache blocks 64 bytes long This option also indicates that a single primary cache is used for both instructions and data therefore it may not be used with the Zpdcache or Zpicache options If this option is not used the cache characteristics are determined by the CPU type retain Retain the extra relation information that the Concurrent link editor to the object file This information is provided so analyze can optimize things like assigned gotos correctly Normally this information is stripped af
386. s and ordinary 1n files except that functions and variables used inconsistently in the library file or defined in the library file but not used in the source files elicit no complaints To create your own lint library insert the directive LINTLIBRARY at the head of a C source file then invoke lint for that file with the o option and the library name that will be given to 1 lint ox files headed by LINTLIBRARY causes only definitions in the source files headed by LINTLIBRARY to be written to the file 1lib 1x 1n Note the analogy of lint o to cc o A library can be created from a file of function prototype declarations in the same way except that both LINTLIBRARY and PROTOLIBn must be inserted at the head of the dec larations file If n is 1 prototype declarations will be written to a library 1n file just as are 10 7 Compilation Systems Volume 1 Tools lint Filters old style definitions If n is O the default the process is canceled Invoking lint with y is another way of creating a lint library lint y ox filel c file2 c causes each source file named on the command line to be treated as if it began with LINTLIBRARY and only its definitions to be written to 11ib 1x 1n By default lint searches for lint libraries in the standard place To direct lint to search for a lint library in a directory other than the standard place specify the path of the directory with the L opt
387. s been set aside Each process that uses the table then gets a private copy of the library s data segment including the table and an additional copy of the table in its own data segment Moreover each process pays a performance penalty for the overhead of copying the table at run time Finally because the space for the table is allocated when the executable is built the application will not have enough room to hold any new messages you might want to add in the future A functional interface overcomes these difficulties strerror might be implemented as follows static const char msg Error 0 Not owner No such file or directory 4 19 Compilation Systems Volume 1 Tools 4 20 char strerror int err if err lt 0 err gt sizeof msg sizeof msg 0 return 0 return char msg err The message array is static so no application space is allocated to hold a separate copy Because no application copy exists the dynamic linker does not waste time moving the table New messages can be added because only the library knows how many messages exist Finally note the use of the type qualifier const to identify data as read only Whereas writable data are stored in a shared object s data segment read only data are stored in its text segment For more on const see the Concurrent C Reference Manual In a similar way you should try to allocate buffers dynamically at run time instead of defining th
388. s may be used to group operations where needed All the operands of an expression given to eval must ultimately be numeric The numeric value of a true relation like 1 gt 0 is 1 and false is O The precision in eval is 32 bits on the UNIX operating system As a simple example you can define M to be 2 N 1 with define M eval 2 N 1 Then the sequence define N 3 M 2 gives 9 as the result A new file can be included in the input at any time with the built in macro include Compilation Systems Volume 1 Tools Diversions include filename inserts the contents of filename in place of the macro and its argument The value of include its replacement text is the contents of the file If needed the contents can be captured in definitions and so on A fatal error occurs if the file named in include cannot be accessed To get some control over this situation the alternate form sinclude silent include can be used This built in says nothing and continues if the file named cannot be accessed m4 output can be diverted to temporary files during processing and the collected material can be output on command m4 maintains nine of these diversions numbered through 9 If the built in macro divert n is used all subsequent output is put onto the end of a temporary file referred to as n Diverting to this file is stopped by the divert or divert 0 macros which resume the normal output process
389. s of the indicated section type exist a new Output Section Descriptor is created and the section is placed so as to maintain the following section type order SDYNAMIC SPROGBITS SSYMTAB SSTRTAB SRELA SREL SHASH SNOTE SNOBITS The bss section in Figure 4 3 illustrates this point NOTE If the input section has a user defined section type value 1 e between SHT_LOUSER and SHT_HIUSER see Chapter 22 Executable and Linking Format ELF it is treated as a SPROGBITS section Note that no method exists for naming this section type value in the mapfile but these sections can be redirected using the other attribute value specifications section flags section name in the entrance criteria 3 If a segment contains no sections after all of the command line object files and libraries have been read in no program header entry is produced for that segment 4 33 Compilation Systems Volume 1 Tools NOTE Input sections of type SSYMTAB SSTRTAB SREL and SRELA are used internally by 1d Directives that refer to these section_types can only map output sections produced by 1d to segments Error Messages When using the mapfile option 1d can return the following types of error messages Warnings Do not stop execution of the link editor nor prevent the link editor from producing a viable a out Fatal Errors Stop execution of the link editor at the point at which the fatal error occurred
390. s the replacement for the Z ID keyword see the get 1 page It prints on the standard output whatever follows the string until the first double quote greater than symbol gt backslash 1 new line null or non printing character For example if an SCCS file called s prog c a C language source file contains the following line char id SWS and the command get r3 4 s prog c Tracking Versions with SCCS is used the resulting g file is compiled to produce prog o and a out Then the command what prog c prog o a out produces prog c prog c 3 4 prog o prog c 3 4 a out prog c 3 4 The string searched for by what need not be inserted with an ID keyword of get it may be inserted in any convenient manner The sccsdiff Command The sccsdiff command determines and prints on the standard output the differences between any two versions of an SCCS file The versions to be compared are specified with sccsdiff r in the same way as with get r SID numbers must be specified as the first two arguments The SCCS file or files to be processed are named last Directory names and a lone hyphen are not acceptable to sccsdiff The following is an example of the format of scesdiff sccsdiff r3 4 r5 6 s abc The differences are printed the same way as by diff The comb Command The comb command lets the user reduce the size of an SCCS file It generates a shell procedure on the standard output which recon
391. se 10 37 variable unused in function 22222 ccc eee ee eee eens 10 37 10 Analyzing Your Code with lint Introduction to lint lint checks for code constructs that may cause your C program not to compile or to execute with unexpected results Lint issues every error and warning message produced by the C compiler It also issues lint specific warnings about potential bugs and portability problems In particular Lint compensates for separate and independent compilation of files in C by flagging inconsistencies in definition and use across files including any libraries you have used In a large project environment especially where the same function may be used by different programmers in hundreds of separate modules of code lint can help discover bugs that otherwise might be difficult to find A function called with one less argument than expected for example looks at the stack for a value the call has never pushed with results correct in one condition incorrect in another depending on whatever happens to be in memory at that stack location By identifying dependencies like this one and dependencies on machine architecture as well Lint can improve the reliability of code run on your machine or someone else s Options and Directives lint is a static analyzer which means that it cannot evaluate the run time consequences of the dependencies it detects Certain programs may contain hundreds of unreachable break statements a
392. se cscope to locate the parts of the code that are generating the message Compilation Systems Volume 1 Tools Step 1 Set Up the Environment cscope is a screen oriented tool that can only be used on terminals listed in the Terminal Information Utilities terminfo database Be sure you have set the TERM environment variable to your terminal type so that cscope can verify that it is listed in the terminfo database If you have not done so assign a value to TERM and export it to the shell as follows TERM ferm_name export TERM You may now want to assign a value to the EDITOR environment variable By default cscope invokes the vi editor The examples in this chapter illustrate vi usage If you prefer not to use vi set the EDI TOR environment variable to the editor of your choice and export EDITOR EDITOR emacs export EDITOR Note that you may have to write an interface between cscope and your editor For details see Command Line Syntax for Editors on page 9 18 If you want to use cscope only for browsing without editing you can set the VIEWER environment variable to pg and export VIEWER cscope will then invoke pg instead of vi An environment variable called VPATH can be set to specify directories to be searched for source files See Using Viewpaths on page 9 13 Step 2 Invoke cscope 9 2 By default cscope builds a symbol cross reference table for all the C lex and yacc s
393. sembler is available on supporting hardware plat forms The assembler accepts instruction mnemonics appropriate to the particular under lying architecture An extended set of directives or pseudo ops extends the programmer s capability for specifying data and section control A subset of these directives is common to each platform The following sections describe the assembly statements and directives The available instructions and their syntax and semantics may be found in the reference manuals and documents listed below Title Chapter 3 PowerPC Instruction Set Summary of this manual Assembler Language Reference for IBM AIX Version 3 for RISC System 6000 PowerPC 604 RISC Microprocessor User s Manual PowerPC Microprocessor Family The Programming Environments PowerPC User Instruction Set Architecture Assembler Operation Input to the assembler is a source file containing instruction mnemonics and directives The assembler processes this input in two passes During the first pass it reads each of the instructions and directives creates a symbol table containing information about every symbol seen within the assembly source and creates other internal tables describing the instructions and directives it reads During the second pass the assembler creates a relocatable object file This object file is in ELF format See Chapter 22 Executable and Linking Format ELF for details The text se
394. ses Only the information to the right of the numbers would actually appear in the mapfile 1 elephant bss peanuts o popcorn o 2 monkey PROGBITS AX 3 monkey bss 4 monkey LOAD V0x80000000 L0x40000 5 donkey bss 6 donkey RX A0x1000 7 text V0x80008000 Figure 4 1 User Defined Mapfile Four separate segments are manipulated in this example The implicitly declared segment elephant line 1 receives all of the bss sections from the files peanuts o and popcorn o Note that popcorn o matches any popcorn o file that may have been entered on the 1d command line the file need not be in the current directory On the other hand if var tmp peanuts o were entered on the 1d command line it would not match peanuts o because it is not preceded by a The implicitly declared segment monkey line 2 receives all sections that are both SPROGBITS and allocatable executable AX as well as all sections not already in the segment elephant with the name bss line 3 The bss sections entering the monkey segment need not be PROGBITS or allocatable executable because the section type and section flags values were entered on a separate line from the section name value An and relationship exists between attributes on the same line as illustrated by SPROGBITS and AX on line 2 An or relationship exists between attributes for the same segment that span more than one line as illustrated by PROGBITS AX on line 20
395. sfy unresolved external references at run time You use the same sequence of commands when you create 1ibfoo 2 cc ZPIC Zlink so h libfoo 2 o libfoo 2 functionl c function2 c function4 c ln libfoo 2 libfoo so Now when users specify cc L dir filel c file2 c file3 c lfoo The name libfoo 2 will be stored in their executables and their programs will be linked with the new library version at run time Multiply Defined Symbols 4 22 Multiply defined symbols except for different sized initialized data objects are not reported as errors under dynamic linking To put that more formally the link editor will not report an error for multiple definitions of a function or a same sized data object when each such definition resides within a different shared object or within a dynamically linked executable and different shared objects The dynamic linker will use the definition in whichever object occurs first on the cc command line You can however specify Qsymbolic when you create a shared object cc ZPIC Zlink so Zsymbolic o libfoo so functionl c function2 c function3 c to insure that the dynamic linker will use the shared object s definition of one of its own symbols rather than a definition of the same symbol in an executable or another library In contrast multiply defined symbols are generally reported as errors under static linking We say generally because definitions of so called weak symbols can be hidden from the
396. sor Level Same as mtspr 1020 rS mtthrm2 rS Move To Thermal 1 750 only Supervisor Level Same as mtspr 1021 rS mtthrm3 rS Move To Thermal 1 750 only Supervisor Level Same as mtspr 1022 rS mtxer rS Move To Fixed Point Exception Register Same as mtspr 1 rS mul o TrA rB Multiply 601 only E mulhd T rA rB Multiply High Doubleword mulhdu rT rA rB Multiply High Doubleword Unsigned mulhw T rA rB Multiply High Word mulhwu rT rA rB Multiply High Word Unsigned mulld o T rA rB Multiply Low Doubleword mulli rT rA SI Multiply Low Immediate muli mullw o T rA rB Multiply Low Word muls o nabs o TTA Negative Absolute Value 601 only P nand rA rS rB Not AND x neg o T rA Negate nop No Operation 7 Same as ori r0 r0 0 no op No Operation nop Same as ori r0 r0 0 not rA rS NOT Same as nor rA rS rS nor rA rS rB Not OR E or rA rS rB OR 3 20 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC RS 6000 i Syntax of Operands Description POWER Mnemonic Mnemonic orc rA rS rB OR with Complement ori rA rS UI OR Immediate oril oris rA rS UI OR Immediate Shifted oriu rfi Return From Interrupt 7 Supervisor Level rldcl rA rS rB MB Rotate Left Doubleword then Clear Left ridcr rA rS rB ME Rotate Left Doubleword then Clear Right ridic rA rS SH MB Rotate Left Doubleword Immediate then Clear rldicl rA rS SH MB Rotate Left Do
397. ssage is issued only when lint is invoked with p and is not issued for the generic pointer void 1 void fun 2 3 int i 4 char c 5 void v 6 i int c 7 i int v 8 warning pointer casts may be troublesome 6 Analyzing Your Code with lint precedence confusion possible parenthesize Format Simple An expression that mixes a logical and a bitwise operator was not parenthesized The message is suppressed when lint is invoked with h 1 void fun 2 3 int x 0 m 0 MASK 0 i 4 i x m 0 5 i x amp MASK 0 eval d x amp MASK 0 6 i MASK 1 amp x eval d MASK 1 amp x 7 5 warning precedence confusion possible parenthesiz 6 warning precedence confusion possible parenthesiz precision lost in bit field assignment Format Simple A constant was assigned to a bit field too small to hold the value without truncation Note that in the following example the bit field z may have values that range from 0 to 7 or 4 to 3 depending on the machine 1 void fun 2 3 struct 4 signed x 3 max value allowed is 3 5 unsigned y 3 max value allowed is 7 6 int z 3 max value allowed is 7 7 bs 8 s x 3 9 s x 4 10 s y 7 11 S y 8 1 2 Siz C 13 S Z 8 14 9 warning precision lost in bit field assignment 4 11 warning precision lost in bit field assignment 0x8 13 warning
398. ssumed to have no arguments Leading unquoted blanks tabs and new lines are ignored while collecting arguments Left and right single quotes are used to quote strings The value of a quoted string is the string stripped of the quotes When a macro name is recognized its arguments are collected by searching for a matching right parenthesis If fewer arguments are supplied than are in the macro definition the trailing arguments are taken to be null Macro evaluation proceeds normally during the collection of the arguments and any commas or right parentheses that appear in the value of a nested call are as effective as those in the original input text After argument collection the value of the macro is pushed back onto the input stream and rescanned You invoke m4 with a command of the form m4 file file file Compilation Systems Volume 1 Tools Each argument file is processed in order If there are no arguments or if an argument is a hyphen the standard input is read If you are eventually going to compile the m4 output you could use a command something like this m4 filel m4 gt filel c You can use the D option to define a macro on the m4 command line Suppose you have two similar versions of a program You might have a single m4 input file capable of generating the two output files For example file1 m4 could contain lines such as R 1 do_something R 2 do_something makefiles are discussed in Chapter 13 Managing
399. st also specify the path of the directory in which it is stored with either the environment variable LD RUN PATH at link time or the environment variable LD_LIBRARY_PATH at run time LD RUN PATH dir iexport LD RUN PATH LD LIBRARY PATH dir iexport LD_LIBRARY_PATH It s best to use an absolute path when you set these environment variables Note that LD_LIBRARY_PATH is read both at link time and at run time To direct the link editor to search libx a where libx so exists in the same directory turn off the dynamic linking default with the Zlink static option cc Zlink static L dir filel c file2 c file3 c 1x That command will direct the link editor to search 1ibc aas well as libx a To link your program statically with libx a and dynamically with libc so use the Zlibs static and Zlibs dynamic options to turn dynamic linking off and on cc L dir filel c file2 c file3 c Zlibs static 1x Zlibs dynamic Files including libraries are searched for definitions in the order they are listed on the cc command line The standard C library is always 5 m4 Macro Processor Introduction rE kek Mb bL te e ee e at 5 1 m Macros a use Love cadet ee eer mote des i at LAO S AEN UR 5 2 Defining Macros x n lae CRDI PEU REMO De at 5 2 Quoling ooa toe AR etiem e ee eto eed ett sess 5 3 Arguments sce otis n e LACE e TOSS eR AGE 5 5 Arithmetic Built Ins 2 0 he 5 7 File Inclusion og exem UR Re UE UR Ae EA Us 5 7 DIVELSIONS 27 uen tre casada
400. statement reduce or read some more input shift and eventually recognize ises as a statement One way to resolve the problem is to invent a new token REDUCE whose sole purpose is to give the correct precedence for the rules 7 19 Compilation Systems Volume I Tools token SIMPLE IF nonassoc REDUCE nonassoc ELSE e Exe VII SIMPLE if_stmnt if stmnt IF stmnt prec REDUCE printer samples se IF stmnt ELSE stmnt printf if then else Since the precedence associated with the second form of if stmnt is higher now yace will try to match that rule first and no conflict will be reported Actually in this simple case the new token is not needed Snonassoc IF Snonassoc ELSE would also work Moreover it is not really necessary to resolve the conflict in this way because as we have seen yace will shift by default in a shift reduce conflict Resolving conflicts is a good idea though in the sense that you should not see diagnostic messages for correct specifications Error Handling 7 20 Error handling is an extremely difficult area and many of the problems are semantic ones When an error is found for example it may be necessary to reclaim parse tree storage delete or alter symbol table entries and or typically set switches to avoid generating any further output It is seldom acceptable to stop all processing when an error is found It is more useful to continue scannin
401. structs the file by discarding unwanted deltas and combining other specified deltas It is not recommended that comb be used as a matter of routine In the absence of any key letters comb preserves only leaf deltas and the minimum number of ancestor deltas necessary to preserve the shape of an SCCS tree The effect of this is to eliminate middle deltas on the trunk and on all branches of the tree Thus in Figure 14 3 deltas 1 2 1 3 2 1 1 4 and 2 1 would be eliminated Some of the key letters used with this command are s This option generates a shell procedure that produces a report of the percentage space if any the user will save This is often useful as a preliminary check p This option is used to specify the oldest delta the user wants preserved 14 25 Compilation Systems Volume 1 Tools c This option is used to specify a list see the get 1 page for its syntax of deltas the user wants preserved All other deltas will be discarded The shell procedure generated by comb is not guaranteed to save space A reconstructed file may even be larger than the original Note too that the shape of an SCCS file tree may be altered by the reconstruction process The val Command SCCS Files Protection 14 26 The val command is used to determine whether a file is an SCCS file meeting the characteristics specified by certain key letters It checks for the existence of a particular delta when the SID for that delta is spe
402. sumably month name day and year are defined in greater detail elsewhere In the example the comma is enclosed in single quotes This means that the comma is to appear literally in the input The colon and semicolon merely serve as punctuation in the rule and have no significance in evaluating the input With proper definitions the input July 4 1776 might be matched by the rule The lexical analyzer is an important part of the parsing function This user supplied routine reads the input stream recognizes the lower level constructs and communicates these as tokens to the parser The lexical analyzer recognizes constructs of the input stream as terminal symbols the parser recognizes constructs as non terminal symbols To avoid confusion we will refer to terminal symbols as tokens There is considerable leeway in deciding whether to recognize constructs using the lexical analyzer or grammar rules For example the rules 7 1 Compilation Systems Volume 1 Tools month name J a n month name F e p A month_name D e c 5 might be used in the above example While the lexical analyzer only needs to recognize individual letters such low level rules tend to waste time and space and may complicate the specification beyond the ability of yacc to deal with it Usually the lexical analyzer recognizes the month names and returns an indication that a month name is seen In this case month name is a token and the detailed
403. t For example suppose you are part of a software project There is an official set of source files in directories below s1 ofc Each user has a home directory usr you If you make changes to the software system you may have copies of just those files you are changing in usr you src cmd progl The official versions of the entire program can be found in the directory s1 ofc src cmd progl Suppose you use cscope to browse through the three files that comprise prog1 namely fl c 2 c and 3 c You would set VPATH to usr you and fs1 ofc and export it as in VPATH usr you fsl ofc export VPATH You would then make your current directory usr you src cmd progl and invoke cscope cscope The program will locate all files in the viewpath In case duplicates are found cscope uses the file whose parent directory appears earlier in VPATH Thus if 2 c is in your directory and all three files are in the official directory cscope will examine 2 c from your directory and 1 c and 3 c from the official directory The first directory in VPATH must be a prefix usually SHOME of the directory you will be working in Each colon separated directory in VPATH must be absolute it should begin at 9 13 Compilation Systems Volume 1 Tools Stacking cscope and Editor Calls cscope and editor calls can be stacked That means that when cscope puts you in the editor to view a reference to a symbol and there is another r
404. t S YACC S YFLAGS y My ERC eC AY S YACC YFLAGS lt CC CFLAGS c y tab c Say ty alos mv y tab o e 0 S GET S GFLAGS lt YACC S YFLAGS y CC CFLAGS c y tab c Exp a DES Y mv y tab o o 5 LEX LFLAGS mv lex yy c S GET GFLAGS lt S LEX LFLAGS 1 mv lex yy c rm f 1 S LEX LFLAGS lt CC CFLAGS c lex yy c rm f lex yy c mv lex yy o OR S GET GFLAGS lt S LEX S LFLAGS 1 S CC S CFLAGS e lex yy c ian Ic OVA Or tese mv lex yy o 13 22 Managing File Interactions with make AS ASFLAGS AR ARFLAGS A et S GET GFLAGS S AS S ASFLAGS S AR S ARFLAGS rmi s Iso AS ASFLAGS GET GFLAGS AS ASFLAGS Sey Hie eS F77 S FFLAGS c S AR S ARFLAGS 8 rm f lt F f 0 ES S GET GFLAGS lt si i FFLAGS c S AR S ARFLAGS 8 rm i fo F77 S FFLAGS 5 GET GFLAGS F77 S FFLAGS Sgn ae OE C C C FLAGS S AR S ARFLAGS EM SEL EO Ce a S GET GFLAGS lt C C C FLAGS S AR S ARFLAGS Saji CON Cor C C C FLAGS ANOS S GET GFLAGS C C C FLAGS A O 13 23 Compilation Systems Volume 1 Tools 13 24 S YACC YFLAGS lt mv y tab c GET GFLAGS lt YACC S YFLAGS MUY aca rm f Y YACC YFLAGS lt C C C FLAGS a A Ae mv
405. t ID keywords interspersed with optional user text Data keywords are replaced by appropriate values according to their definitions For example TIS is defined as the data keyword replaced by the SID of a specified delta Similarly F is the data keyword for the SCCS file name currently being processed and C is the 14 21 Compilation Systems Volume 1 Tools comment line associated with a specified delta All parts of an SCCS file have an associated data keyword For a complete list see the prs 1 page There is no limit to the number of times a data keyword may appear in a data specification Thus for example prs d I this is the top delta for F I s abc may produce on the standard output 2 1 this is the top delta for s abc 2 1 Information may be obtained from a single delta by specifying its SID using prs r For example prs d F I comment line is C r1 4 s abc may produce the following output s abc 1 4 comment line is THIS IS A COMMENT If r is not specified the value of the SID defaults to the most recently created delta In addition information from a range of deltas may be obtained with 1 or e The use of prs e substitutes data keywords for the SID designated with r and all deltas created earlier while prs 1 substitutes data keywords for the SID designated with r and all deltas created later Thus the command prs d I r1 4 e s abc may output biusombpnun D MOM
406. t or archive library as input In other words when you create libfoo so you can link it with a library you have already created say libsharedob so cc Zlink so o libfoo so L dir functionl o function2 o function3 o lsharedob That command will arrange for libsharedob so to be linked with libfoo so when at run time libfoo so is linked with your program Note that here you will have to point the dynamic linker to the directories in which both libfoo so and libsharedob so are stored Specifying Directories to Be Searched by the Link Editor In the previous subsection we created the archive library 1ibfoo a and the shared object libfoo so For the sake of discussion we ll now say that both these libraries are stored in the directory home mylibs We ll also assume that you are creating your executable in a different directory In fact these assumptions are not academic They reflect the way most programmers organize their work on the PowerUX system The first thing you must do if you want to link your program with either of these libraries is point the link editor to the home mylibs directory by specifying its path name with the L option cc L home mylibs filel c file2 c file3 c lfoo The L option directs the link editor to search for the libraries named with 1 first in the specified directory then in the standard places In this case having found the directory home mylibs the link editor will search 1ibfoo so rather
407. t sr RA nt RB nt RB inst maskg int RA int RB nt RA clcs RA cntlzw RA RS dcbf RB dcbi RB dcbst RB dcbt RB dcbtst RA RB dcbz RB dsa eciwx RT RA RB ecowx RS RA RB eieio esa fres FRT FRB frsqrte FRT FRB fsel FRT FRA FRC FRB icbi RA RB isync lhbrx RA RB lwarx RA RB lworx RT RA RB maskg RT RA RB maskir RT RA RB mffs FRT mfmsr RT mfspr RT spr spr must be an integer constant Extended mnemonics are generated for appropriate register numbers mfsr RT sr sr must be an integer constant 3 38 Table 3 8 Compiler Intrinsics Cont PowerPC Instruction Set Summary Intrinsic Description RT int inst mfsrin void RB RT int inst mftbl void RT int inst mftbu void inst mtfsbO int bit inst mtfsbl int bit inst mtfsf int mask double FRB inst mtfsfi int n unsigned u inst mtmsr int RS inst mtspr int spr int RS inst mtsr int sr int RS inst mtsrin int RS void RB inst nop inst rfi inst sc inst sthbrx short RS void RA int RB inst stwbrx int RS void RA int RB RT int inst stwcx int RS void RA int RB inst sync void inst tlbia void inst tlbie void RB inst tlbld void RB inst tlbli void RB mfsrin RT RB mftb RT 268 mftb RT 269 mtfsb0 bit bit must be an integer constant mtfsbl bit bit must be an in
408. t to undefine Built ins can be removed with undefine as well undefine define Note that once a built in is removed or redefined its original definition cannot be reused Macros can be renamed with de n Suppose you want the built in define to be called XYZ You specify Arguments m4 Macro Processor define XYZ defn define undefine define After this XYZ takes on the original meaning of define XYZ A 100 defines Ato be 100 The built in ifdef provides a way to determine if a macro is currently defined Depending on the system a definition appropriate for the particular machine can be made as follows ifdef pdp11 define wordsize 16 ifdef u3b define wordsize 32 The ifdef macro permits three arguments If the first argument is defined the value of ifdef is the second argument If the first argument is not defined the value of ifdef is the third argument ifdef unix on UNIX not on UNIX If there is no third argument the value of ifdef is null The previous sections focused on the simplest form of macro processing replacing one string with another fixed string Macros can also be defined so that different invocations have different results In the replacement text for a macro the second argument of its define any occurrence of n is replaced by the nth argument when the macro is actually used The macro bump
409. tches y z Other lex operators are noted as they arise in the discussion below lex recognizes all the C language escape sequences Table 6 1 lex Operators Expression Description x x if xis a lex operator xy xy even if x or y are lex operators except V xy X Or y x z X y OF Z x any character but x any character but new line X x at the beginning of a line lt y gt x x when lex is in start condition y x x at the end of a line x optional x x 0 1 2 instances of x xt 1 2 3 instances of x x m n m through n occurrences of x xx yy either xx or yy x the action on x is the action for the next rule x x x y x but only if followed by y xx the translation of xx from the definitions section Once the scanner recognizes a string matching the regular expression at the start of a rule it looks to the right of the rule for the action to be performed You supply the actions Kinds of actions include recording the token type found and its value if any replacing one token with another and counting the number of instances of a token or token type You write these actions as program fragments in C An action may consist of as many state ments as are needed for the job at hand You may want to change the text in some way or simply print a message noting that the text has been found So to recognize the expression Amelia Earhart and to note such recognition the rule Amelia Earhart printf found
410. teger constant mtfsf mask FRB mask must be an integer constant mtfsfi n u n and u must be integer constants mtmsr RS mtspr spr RS spr must be an integer constant Extended mnemonics are generated for appropriate register numbers mtsr sr RS sr must be an integer constant mtsrin RS RB ori r0 r0 0 sthbrx RS RA RB Stwbrx RS RA RB Stwcx RS RA RB mfcr RT rlwinm RT RT 3 31 31 Sync tlbia tlbie RB tlbld RB rlbli RB 3 39 Compilation Systems Volume 1 Tools 3 40 Table 3 8 Compiler Intrinsics Cont Intrinsic Description inst tlbsync void tlbsync inst tw int to int RA int RB tw to RA RB inst twi int to int RA int si RT unsigned int ref double first_half double FA RT unsigned int ref double second half double FA RT unsigned int ref_float_as_uint float FA RT unsigned int rot unsigned int RA int RB __set_fpscr double RA set thread reg unsigned int RA RT int abs int RA FT float or double fabs float or double FB FT double pow double FA double FB FT float powf float FA float FB FT double sqrt double FB FT single sqrtf single FB twi to RA si Obtain the bit pattern of the first word of a double precision floating point value as an integer Obtain the bit pattern of the second word of a double precision float ing point value as an integer Obtain the bit pattern of a
411. ter optimization If you are going to want to profile or disassemble the program file this option will retain the extra relocation information so the additional processing can be more accurate rmask register list Specify a list of registers to be considered live at a return instruction To optimize pure C or Fortran 77 code use Zrmask r3r4 The default mask contains r3 through r15 rtag character Specify a character to enclose all routine names output in reports This is for an Ada filter that translates raw routine names into Ada R M expanded names stag character Specify a character to enclose all source file names output in reports This is for an Ada filter that translates raw source file names into actual file names stage status Add output describing the status of all pipeline stages each cycle to the disassembly output of the d option strip Strip the object file before writing it out Performance Analysis Assumptions and Constraints report The timing information is not totally accurate The worst case timing information should really be generated by propagating live on entry resource utilizations backwards through the flow graph to see how they interact with live on exit resource utilizations from the predecessor blocks but this is complex and would require a great deal more code to do the analysis analyze assumes all memory references are cache hits Thus the timing information assumes there will never be an
412. th error reports You can save time by using tools to automate project management This part of the manual covers tools that give you control over projects products and files For example Remembering file locations and dependencies and product generation steps for a developing product can be cumbersome You can store this information in description files for the make tool to process Chapter 13 Managing File Interactions with make discusses make and its description files Retaining an audit trail of editing changes can be useful in debugging and documenting a developing product Chapter 14 Tracking Versions with SCCS describes SCCS the Source Code Control System that allows you to capture this information 12 1 Compilation Systems Volume 1 Tools 12 2 13 Managing File Interactions with make Introduction 5 ein bb ek hee pL te Me edet ane Mean 13 1 Basic Features a wc ko dade tee aeter metes e ende 13 2 Parallel make mem ER RE NEUTRO AUR I ers 13 5 Description Files and Substitutl0NS o ooooooocoococonorcror nenn 13 6 COMMENDS sei ESN REN bU SC Ree due eed Gace ee BAe RO Race due SCA NOR 13 6 Continuation Lines 13 6 Macro DETONANTE 13 6 General BOE vun E ea ee E SUE A NUN na 13 6 Dependency Information ooooococococooo nennen nn 13 7 Executable Commands 0 0 0 ccc ccc cece eee eee nes 13 7 Extensions of 9 and lt oo cece eens 13 8 Output Translations event e ond ce eet ees 13 8
413. that define has arguments If the macro name is not immediately followed by a left parenthesis it is assumed to have no arguments In the previous example then N is a macro with no arguments A macro name is only recognized as such if it appears surrounded by characters which cannot be used in a macro name In the following example define N 100 if NNN gt 100 the variable NNN is unrelated to the defined macro N even though the variable contains Ns m4 expands macro names into their defining text as soon as possible define N 100 define M N defines M to be 100 because the string N is immediately replaced by 100 as the arguments of define M N are collected To put this another way if N is redefined M keeps the value 100 There are two ways to avoid this behavior The first which is specific to the situation described here is to interchange the order of the definitions define M N define N 100 Now Mis defined to be the string N so when the value of M is requested later the result will always be the value of N at that time because the M will be replaced by N which will be replaced by 100 The more general solution is to delay the expansion of the arguments of define by quoting them Any text surrounded by left and right single quotes is not expanded immediately but has the quotes stripped off as the arguments are collected The value of the quoted string is the string stripped of the quotes Compilat
414. the execution of the command These four macros are described later in Description Files and Substi tutions on page 13 6 The following fragment shows assignment and use of some macros OBJECTS x o y o z o LIBES lm prog OBJECTS cc S OBJECTS LIBES o prog The command make LIBES 11 lm 13 3 Compilation Systems Volume 1 Tools loads the three objects with both the lex 11 and the math 1m libraries because macro definitions on the command line override definitions in the description file In UNIX system commands arguments with embedded blanks must somehow be quoted As an example of the use of make a description file that might be used to maintain the make command itself is given The code for make is spread over a number of C language source files and has a yace grammar The description file contains the following Description file for the make command FILES Makefile defs h main c doname c misc c files c dosys c gram y OBJECTS main o doname o misc o files o dosys o gram o LIBES LINT lint p CFLAGS O LP lp make OBJECTS CC CFLAGS o make OBJECTS LIBES size make OBJECTS defs h cleanup EMO game du installs make size make usr ccs bin make cp make usr ccs bin make amp amp rm make dosys c doname c files c main c misc c gram c S LINT dosys c doname c files c main c misc c gram c print files that are out of dat
415. the use of at most one of global local and weak for each symbol in the input file ELF Symbol Attributes These directives provide attributes for symbols Refer to Chapter 22 Executable and Linking Format ELF for information about the symbol table 2 17 Compilation Systems Volume 1 Tools type identifier type identifier is declared with type type The assembler permits one of the following flags to be specified as type The assembler requires that the given value be preceded witha no_type no specified type object a data object function a function or other executable code For example type abc object associate abc with a data object size identifier size The size size is associated with identifier size specifies the size in bytes and is of absolute type For example size 6 indicate the identifier has size 6 version value The quoted string value is compared with an internal assembler version string If value is lexicographically greater than the internal string the assembler produces a fatal error message and exits This directive is optional If present it must appear first in the assembly file The only acceptable values are 03 00 and 02 00 02 00 suppresses the auto matic removal of a leading underscore from labels and alphanumeric labels Additionally 03 00 requires that be prefixed to certain keywords as described throughout this chapter Miscellaneous O
416. there are no explicit commands or relevant built in rules the commands associated with the name DEFAULT are used if it exists Dependents on this target are not removed when quit or interrupt 1s pressed Same effect as the s option Same effect as the i option 13 17 Compilation Systems Volume 1 Tools PRECIOUS Dependents of the PRECIOUS entry will not be removed when quit or interrupt are pressed Finally the remaining arguments are assumed to be the names of targets to be made and the arguments are done in left to right order If there are no such arguments the first name in the description file that does not begin with the symbol is made Environment Variables Environment variables are read and added to the macro definitions each time make executes Precedence is a prime consideration in doing this properly The following describes make s interaction with the environment A macro MAKEFLAGS is maintained by make The macro is defined as the collection of all input flag arguments into a string without minus signs The macro is exported and thus accessible to recursive invocations of make Command line flags and assignments in the makefile update MAKEF LAGS Thus to describe how the environment interacts with make the MAKEFLAGS macro environment variable must be considered When executed make assigns macro definitions in the following order 1 Read the MAKEFLAGS environment variable If
417. thi and Ullman text Compilers Principles Techniques and Tools Addison Wesley 1986 lex uses a table to represent its finite automaton The maximum number of states that the finite automaton allows is set by default to 500 If your lex source has a large number of rules or the rules are very complex this default value may be too small You can enlarge the value by placing another entry in the definitions section of your lex source as follows n 700 This entry tells lex to make the table large enough to handle as many as 700 states The v option will indicate how large a number you should choose If you have need to increase the maximum number of state transitions beyond 2000 the designated parameter is a thus a 2800 6 17 Compilation Systems Volume I Tools Summary of Source Format 6 18 The general form of a lex source file is definitions oo 676 rules oe oo user routines The definitions section contains any combination of definitions of abbreviations in the form name space translation included code in the form oe C code oe start conditions in the form Start namel name2 changes to internal array sizes in the form Sx nnn where nnn is a decimal integer representing an array size and x selects the parameter as follows p positions n states e tree nodes a transitions k packed character classes o Output array size Lines in the rules section have the
418. tion Specific and Optional Instructions Cont Mnemonic 601 602 603 e 604 e 620 750 rotld v rotldi v rotrdi v rrib v slbia v slbie v slbiex sld v sldi v sle sleg sliq slliq sllq S S S S S S siq srad v sradi v sraiq s sraq v srd v srdi v sre srea sreg sriq srlig sriq S S 8S 888 8 srq std u std u x stdex stfd u v v v stfd u x v v v ISIS 3 36 PowerPC Instruction Set Summary Table 3 7 Implementation Specific and Optional Instructions Cont Mnemonic 601 602 603 e 604 e 620 750 stfiwx v v v v v stswi v v v v v StSWX v v v v v td v tdi v tdTO v td TOi v tlbia tlbie v v v v v v tlbiex tlbld v v tlbli v v tlbsync v v v v v The Concurrent C compiler provides a number of intrinsic functions to access PowerPC instructions that are not normally generated by C code See the Concurrent C Reference Manual for details on enabling intrinsics The following table gives pseudo prototypes and short descriptions of the provided intrinsics The user might infer the existence of some additional intrinsics However these intrinsics are not guaranteed to behave as expected and should not be used The compiler will generate warnings for any intrinsic inconsistent with the Qt arget architecture option Table 3 8 Compiler Intrinsics Intrinsic Description FRT doub
419. to exclude more than one register Normally the O option uses registers r28 though r31 Performance Analysis help Give a short list and description of keyword options include register Add the named register to the list of registers used to optimize out lis instructions It may be used multiple times to include more than one register Normally the O option uses registers r28 though r31 However if no routine in a program uses r6 though r27 or the frame pointer r2 these registers can be used too Analyze will exit with an error if it finds a use of any of the named registers 12cache cache_size block_size Define the characteristics of the secondary L2 cache for use with the C option The cache size argument is the total secondary cache size It may be suffixed with M for megabytes or K for kilobytes A cache size of 0 means that there is no secondary cache The optional block size argument is the cache block line size in bytes it defaults to 64 bytes For example Z12cache 1m 128 specifies a secondary cache size of 1 megabyte with 128 bytes per cache block If this option is not used the secondary cache is 1 megabyte with 64 byte cache blocks Note that the first character is the letter 1 not the number 1 options filename Tell analyze to read filename for a list of additional options Each additional option should be on a separate line pdcache cache_size block_size sets Define the characteristics of the p
420. to produce an optimized program or to produce a profiling program If args begins with a hyphen the system analyze 1 tool is used and args is passed to it If args does not begin with a hyphen then the first field is considered to be the name of an alternative analyze 1 tool and the remainder of args is passed to it Issue a warning if a user object file contains a global definition or reference of errno Also set the EF PPC ADA flag in the program s ELF header Suppress the output of pointer arrays to tdesc information Qanalyze patch size size OBSS Set the amount of patch space reserved for analyze 1 profiling to size By default the reserved size of the patch space is ten times the size of the program s text section This option is used to change the amount reserved Force undefined externals with a positive size into the bss section even when the r option is used Q dynamic static Qfper value Same as B dynamic static Set appropriate fields in the vendor section so that the floating point control register fpscr is initialized on program start up to value By default the fpscr specifies the round to nearest floating point rounding mode and the enabling of the floating point reserved operand divide by zero and over flow exceptions Use of this option effects an override of the default setting of fpscr at program start up 4 5 Compilation Systems Volume 1 Tools Qfpexcept valu
421. to right If the rule is A B C D then 2 has the value returned by C and 3 the value returned by D The rule expr expr 7 provides a common example One would expect the value returned by this rule to be the value of the expr within the parentheses Since the first component of the action is the literal left parenthesis the desired logical result can be indicated by expr expr 2 By default the value of a rule is the value of the first element in it 1 Thus grammar rules of the form 7 5 Compilation Systems Volume I Tools 7 6 A E B frequently need not have an explicit action In previous examples all the actions came at the end of rules Sometimes it is desirable to get control before a rule is fully parsed yacc permits an action to be written in the middle of a rule as well as at the end This action is assumed to return a value accessible through the usual mechanism by the actions to the right of it In turn it may access the values returned by the symbols to its left Thus in the rule below the effect is to set x to 1 and y to the value returned by C A E B 1 E x 2 y 3 t Actions that do not terminate a rule are handled by yace by manufacturing a new non terminal symbol name and a new rule matching this name to the empty string The interior action is the action triggered by recognizing this added rule yacc treats the above example as if it
422. ty Such a symbol may be defined in the current assembly or it may be defined externally to the current assembly If it is defined in the current assembly as an absolute a text a data or a bss symbol the symbol may be used as if it were not globally visible Its value and type may be used by the link editor to satisfy external references to the symbol If the symbol is not defined in the current assembly the link editor will regard it as an external reference to a global definition of the symbol outside the current assembly Assembler Directives Assembler directives pseudo ops specify location counter control section switching data initialization symbol definitions symbolic debugging information and miscellaneous operations The following notation is used directive directive operand directive and directive are acceptable assembly mnemonics and operand is the kind of operand accepted by the directive Location Counter Control align align alignment The location counter is adjusted so that its value modulo the specified alignment is zero Bytes between the current location counter and the new aligned value are filled with zeroes 10 alignment is the base 2 logarithm of the desired alignment alignment is of manifest type For example align 3 align the location counter to an 8 byte boundary org counter The location counter is set to counter which must be defined and must not exceed the curr
423. ubleword Immediate then Clear Left ridicr rA rS SH ME Rotate Left Doubleword Immediate then Clear Right rldimi rA rS SH MB Rotate Left Doubleword Immediate then Mask Insert rimi rA IS 1B MB ME Rotate Left Then Mask Insert 601 only rlwimil rA rS SH MB ME Rotate Left Word Immediate then Mask Insert rlimi If ME is omitted MB is the mask rather than the begin ning bit of the mask rlwinm rA rS SH MB ME Rotate Left Word Immediate then AND with Mask rlinm If ME is omitted MB is the mask rather than the beginning bit of the mask rlwnm rA rS rB MB ME Rotate Left Word then AND with Mask rinm If ME is omitted MB is the mask rather than the beginning bit of the mask rotld rA rS rB Rotate Left Doubleword Same as rldcl rA rS rB 0 rotldi rA rS n Rotate Left Doubleword Immediate Same as rldicl rA rS n 0 rotlw rA rS rB Rotate Left Word Same as rlwnm rA rS rB 0 31 rotlwil rA rS n Rotate Left Word Immediate Same as rlwinm rA rS n 0 31 rotrdi rA rS n Rotate Right Doubleword Immediate Same as rldicl rA rS 64 n 0 rotrwi rA rS n Rotate Right Word Immediate Same as rlwinm rA rS 32 n 0 31 rrib TAS 1B Rotate Right And Insert Bit 601 only 2 sc System Call svca 3 21 Compilation Systems Volume 1 Tools Table 3 1 PowerPC Instruction Set Cont PowerPC aes Reo Mines Syntax of Operands Description POWER Mnemonic slbia SLB Invalidate All optional Supervisor Level slb
424. umber break cp 0 cp buf gt BSZ void printf constant too long truncated n else ungetc c stdin push back last char read yylval dval atof buf return CONST return c INTERVAL labo ficte oy erra double ay B Cp d returns the smallest interval containing a b c andd used by vmul vdiv routines INTERVAL v ivf ace v hi vom else aliz iil alae Ke return v 7 38 Parsing with yacc INTERVAL vmul a b v double a b INTERVAL v TEEN O Joy as airplay doy W aon dcheck v INTERVAL v Ay gt 0 EV lou e void printf divisor interval contains 0 n return 1 return 0 INTERVAL elle Dy V double a b INTERVAL v return loa aa NV ome b A hre Do LOr 7 39 Compilation Systems Volume I Tools 7 40 2 Analysis SSS SS Ss Replace with Part 2 tab Compilation Systems Volume 1 Tools Part 2 Analysis Part 2 Analysis Part2 Analysis Chapter 8 Introduction to Analysis sess 8 1 Chapter 9 Browsing Through Your Code with cscope suse 9 1 Chapter 10 Analyzing Your Code with lint see 10 1 Chapter 11 Performance Analysis eese 11 1 Compilation Systems Volume 1 Tools 8 Introduction to Analysis Trtroduction 3 I a As SM A eR ee 8 1 Compilation Systems Volume 1 Tools Int
425. ument type inconsistent with format too few arguments for format too many arguments for format for mismatches between the remaining arguments and the conversion specifications lint issues these warnings by default for errors in calls to s printf functions provided by the standard C library PROTOLIBn When nis land LINTLIBRARY is used write to a library 1n file only function prototype declarations in the c file it heads Default is 0 canceling the process SCANFLIKEn Same as PRINTFLIKEn except that the nth argument of the function definition is treated as a s scanf format string By default Lint issues warnings for errors in calls to s scanf functions provided by the standard C library VARARGSn For the function whose definition it precedes suppress function called with variable number of arguments for calls to the function with n or more arguments lint specific Messages This section lists alphabetically the warning messages issued exclusively by lint or subject exclusively to its options The code examples illustrate conditions in which the messages are elicited Note that some of the examples would elicit messages in addition to the one stated 10 12 Analyzing Your Code with lint argument unused in function Format Compound A function argument was not used Preceding the function definition with ARGSUSEDn suppresses the message for all but the first
426. unction returns pointer to automatic parameter function returns value that is always ignored 10 24 Format Simple A function returned a pointer to an automatic variable or a parameter Since an object with automatic storage duration is no longer guaranteed to be reserved after the end of the block the value of the pointer to that object will be indeterminate after the end of the block FPO mMANATA OF WN Aa int fun int x int a 10 int b if x 1 return a else if x 2 return amp b else return amp x warning function returns pointer to warning function returns pointer to automatic warning function returns pointer to parameter Format Compound A function contained a return statement and every call to the function ignored its return value file 1 c 1 int fun 2 3 return 1 4 file 2 c 1 extern int fun 2 int main 3 4 fun 5 return 1 6 function returns value that is always ignored fun Analyzing Your Code with lint function returns value that is sometimes ignored Format Compound A function contained a return statement and some but not all calls to the function ignored its return value file 1 c 1 int fun 2 3 return 1 4 file 2 c 1 extern int fun 2 int main 3 4 if 1 5 return fun 6 else 7 fun 8 return 1 9 10 function returns value that is sometimes ignored fun function value is used but none returned For
427. unctions lsseeeeeeee eee eee eens 16 45 Control Functions ssie iu 0 cece n 16 46 Signals Functions ine ceder are 16 47 User Level Interrupts Functions 0 000 000 008 16 49 Lightweight Processes Functions 00 0002 e ooo 16 49 Access Control Lists Functions 0 0 0 e ee eee eee eee 16 51 Auditing Functions vito 222 ana ad Shee Gis eed 16 51 Levels Functions Kuss 16 51 Other Security Functions 0 0 0 eee eee ee eee 16 52 Encryption and Decryption Functions 004 16 52 Loadable Kernel Modules Functions eee eee 16 53 Other System Environment Functions 04 16 53 Stack Frames ae ee ee eva e enel a reae tere etras 18 2 Where Parameters Are Passed 0 0 0 cece eee eee eee 18 2 General Registers sects eh ea re 18 4 Floating point Registers 00 0 0 eee eee eee ee 18 4 Special Registers i ri Roe hee pete eh 18 5 Scalar Types u ner oe e ke 18 5 Fortran Scalar Types suicida ai 18 6 Object File Format 0 0 eee eee 22 2 32 Bit Data Types de ach te ee ee i etico 22 3 e ident Identification Indexes o ooooooooooo eee 22 6 PowerUX Identification e_ident 0 0 0 cece eee 22 9 Processor Specific Flags e flags 0 0 00 cee ee eee ee 22 9 Special Section Indexes 00 0 eee eee 22 10 Section Types sh type 00 2 eee ee ee eee 22 12 Section Header Ta
428. unctions 16 8 Inserting zero trip tests 20 11 20 12 Instruction mnemonic 2 1 Instruction mnemonics 2 6 Instruction scheduling 20 10 20 24 Instruction set PowerPC 3 2 Internal table Table internal 2 1 Internationalization functions 16 35 Interpreter 1 2 program 1 6 Interval timer functions 16 35 Invocation as 2 2 Index 6 Label numeric 2 5 Labels alphanumeric 2 4 Language high level 1 2 low level 1 2 machine 2 1 processor 1 2 programming 1 1 ld 1 1 4 LD_BIND_NOW 4 16 22 47 LD_BIND_NOW environment variable 4 16 22 47 22 55 LD_LIBRARY_PATH 4 14 4 16 LD_LIBRARY_PATH environment variable 4 7 4 14 4 36 22 52 LD_RUN_PATH 4 15 4 16 LD_RUN_PATH environment variable 4 7 4 15 4 36 ldd 1 4 16 lex 1 1 4 6 1 6 19 lex 1 command line 6 1 6 2 lex 1 definitions 6 12 6 14 6 17 lex 1 disambiguating rules 6 9 lex 1 how to write source 6 3 6 15 lex 1 library 6 2 6 17 lex 1 operators 6 4 6 6 lex 1 quick reference 6 18 6 19 lex 1 routines 6 7 6 10 6 12 lex 1 source format 6 3 6 18 6 19 lex 1 start conditions 6 13 6 14 lex 1 use with yacc 1 6 12 6 15 6 17 7 1 7 3 7 7 7 8 7 22 7 23 lex 1 user routines 6 10 6 11 6 14 6 15 lex 1 yylexQ 6 2 6 15 Lexical analyzer 1 4 lexical analyzer see lex 1 6 2 libraries archive 4 9 creating 4 11 4 13 4 18 4 22 libc 4 9 4 11 libdl 4 10 4 11 4 17 libelf 22 1 libm 4 11 linking with 4 35 naming conventions 4 35 shared object 4 8 22 27 2
429. urce grammar L lex C source grammar L SCCS lex C source grammar Figure 13 1 summarizes the default transformation paths If there are two paths connecting a pair of suffixes the longer one is used only if the intermediate file exists or is named in the description Figure 13 1 Summary of Default Transformation Path If the file x o is needed and an x c is found in the description or directory the x o file would be compiled If there is also an x 1 that source file would be run through lex before compiling the result However if there is no x c but there is an x 1 make would discard the intermediate C language file and use the direct link as shown in Figure 13 1 It is possible to change the names of some of the compilers used in the default or the flag arguments with which they are invoked by knowing the macro names used The compiler names are the macros AS CC C C F77 YACC and L make CC newcc EX The command Managing File Interactions with make will cause the newcc command to be used instead of the usual C language compiler The macros CFLAGS YFLAGS LFLAGS ASFLAGS FFLAGS and C FLAGS may be set to cause these commands to be issued with optional flags Thus make CFLAGS g causes the cc command to include debugging information Archive Libraries The make program has an interface to archive libraries A user may name a member of a library in the following manner projlib object o or
430. ust 1 Enter mapfile directives into a file this is your mapfile 2 Enter the following option on the 1d command line M mapfile mapfile is the file name of the file you produced in step 1 If the mapfile is not in your current directory you must include the full path name no default search path exists See the 1d 1 for information on operation of the 1d command Mapfile Structure and Syntax You can enter three types of directives into a mapfile Segment declarations Mapping directives Size symbol declarations Each directive can span more than one line and can have any amount of white space including new lines as long as it is followed by a semicolon You can enter 0 zero or more directives in a mapfile Entering 0 directives causes 1d to ignore the mapfile and use its own defaults Typically segment declarations are followed by mapping directives 1 e you would declare a segment and then define the criteria by which a section becomes part of that segment If you enter a mapping directive or size symbol declaration without first declaring the segment to which you are mapping except for built in segments explained later the segment is given default attributes as explained below This segment is then an implicitly declared segment 4 24 Segment Declarations Link Editor and Linking Size symbol declarations can appear anywhere in a mapfile The following sections describe each directive type For all sy
431. value equal to the numerical value of the digit You put the lexical analyzer code in the subroutines section and the declaration for DIGIT in the declarations section Alternatively you can put the lexical analyzer code in a separately compiled file provided You invoke yace with the d option which generates a file called y tab hthat contains define statements for the tokens and e You include y tab hin the separately compiled lexical analyzer This mechanism leads to clear easily modified lexical analyzers The only pitfall to avoid is using any token names in the grammar that are reserved or significant in C language or the parser For example the use of token names if or while will almost certainly cause severe difficulties when the lexical analyzer is compiled The token name error is reserved for error handling and should not be used naively In the default situation token numbers are chosen by yacc The default token number for a literal character is the numerical value of the character in the local character set Other names are assigned token numbers starting at 257 If you prefer to assign the token numbers the first appearance of the token name or literal in the declarations section must be followed immediately by a nonnegative integer This integer is taken to be the token number of the name or literal Names and literals not defined this way are assigned default definitions by yacc The potential for duplication exists here
432. ved that is without any occurrence of the string orange at all Unlike orange above most of the expressions that we want to search for cannot be specified so easily The expression itself might simply be too long More commonly the class of desired expressions is too large it may in fact be infinite Thanks to the use of operators summarized in Table 6 1 below we can form regular expressions to signify any expression of a certain class The operator for instance means one or more occurrences of the preceding expression the means 0 or occurrence s of the preceding expression which is equivalent of course to saying that the preceding expression is optional and means 0 or more occurrences of the preceding expression It may at first seem odd to speak of 0 occurrences of an expression and to need an operator to capture the idea but it is often quite helpful We will see an example in a moment So m is a regular expression that matches any string of ms mmm m mmmmm and 7 is a regular expression that matches any string of zero or more 7s 77 T1777 777 The empty third line matches because it has no 7s in it at all The operator indicates alternation so that ab cd matches either ab or cd The operators specify repetition so that a 1 5 looks for 1 to 5 occurrences of a Brackets indicate any one character from the string of characters specified between the brackets Thus dgka matches a single d
433. vel Same as mfspr rT 1019 Move From Instruction TLB Miss Address 602 603 e only Supervisor Level Same as mfspr rT 980 Move From L2 Control Register 620 only Supervisor Level Same as mfspr rT 1017 Move From L2 Status Register 620 only Supervisor Level Same as mfspr rT 1018 Move From Link Register Same as mfspr rT 8 Move From Integer Tag Register 602 only Supervisor Level Same as mfspr rT 1022 Move From Mask Register 604 e 620 only Supervisor Level Same as mfspr rT 952 Move From Mask Register Read Only 620 only Supervisor Level Same as mfspr rT 779 Move From Mask Register 1 604e only Supervisor Level Same as mfspr rT 956 Move From Multiply Quotient Register 601 only Same as mfspr rT 0 Move From Machine State Register Supervisor Level Move From Processor ID Register optional 601 604 e 620 only Supervisor Level Same as mfspr rT 1023 3 12 PowerPC Instruction Set Summary Table 3 1 PowerPC Instruction Set Cont PowerPC Mnemonic Syntax of Operands RS 6000 Description POWER Mnemonic mfpmel mfpmc 1rd mfpmc2 mfpmc2rd mfpmc3 mfpmc4 mfpvr mfrpa mfrtel mfrtcu mfsda mfsdr1 mfsebr 1T IT IT IT IT IT IT IT IT IT IT Move From Performance Monitor Counter 1 604 e 620 only Supervisor Level Same as mfspr rT 953 Move From Performance Monitor Counter 1 Read Only 620 only Same
434. vention Encodings 0 000 000 0 eee ee 24 80 Table 24 31 Inline Encodings 0 00 cece eee 24 80 Table 24 32 Ordering Encodings 0 0 0 0 eee eee eee 24 81 Table 24 33 Discriminant Descriptor Encodings 00000 24 81 Table 24 34 Standard Opcode Encodings 0 0 0 0 eee eee ee 24 82 Table 24 35 Extended Opcode Encodings 0 0 00 e eee eee 24 83 Table 24 36 Macinfo Type Encodings 0 0 0 0 e eee eee eee ee 24 83 Table 24 37 Call Frame Instruction Encodings 0 0 0 0 008 24 84 Table 24 38 Current Attributes by Tag Value 0 0 00 00 0000 24 85 Table 25 1 Scalar Types id ee Re 25 3 Table 25 2 Error Indications 0 0 eee eee 25 7 Table 25 3 Allocation Deallocation Identifiers llle 00 00 0000 25 9 Table 25 4 Error Codes isse cR ee e Rees 25 21 XXV Compilation Systems Volume 1 Tools xxvi 1 Software Development Environments Replace with Part 1 tab Compilation Systems Volume 1 Tools Part I Software Development Environments Part 1 Software Development Environments Part 1 Software Development Environments Chapter 1 Introduction to SDEs sess 1 1 Chapter 2 Assembler and Assembly Language eee 2 1 Chapter 3 PowerPC Instruction Set Summary sese 3 1 Chapter 4 Link Editor and Linking eee 4 1 Chapter 5
435. ws you to divide your program into separate sections which will be profiled independently each generating a separate data set in the prof file All you need to do is call a dummy routine once between each section of the program then use the X option to declare these dummy routines as exit points If any basic block begins with a trap instruction of some kind analyze will generate a warning Normally it relies on the flow of control resuming right after the patched instruction but it is uncertain where control will resume after the kernel gets control Unless you know what the routine does it might be wise to exclude it from the list of routines to be profiled analyze is invoked as follows Performance Analysis analyze A C D flag H N O file P file S section X routine W routine weight a routine d file g file i n r file s routine v x Z keyword file The file argument specifies the name of the executable file over which analyze will be run All other arguments are optional and are as follows A C P file S section X routine Include all the routines in the analysis This is the default mode of operation Gather cache activity statistics during profiling This option works with P and has no effect without it It also writes its statistics to file prof as specified by the P option Cache statistics include instruction accesses gathered at each basic b
436. xecution 0 0 cee eee E E e eee 22 35 Program Header i 2 A MENU REIR 22 35 Base Address u as 2 22 ERI tu MEVS oe ae gb eS 22 38 Segment Permissions ennn ETR HEI An ELA EE AR oa eee 22 39 Segment Contents 2 0 0 e 22 40 Note Section sii ae eS RE TIEF Pee 22 41 Program Loading 3 eu IEEE re Re les Bele 22 42 Prograni Interpreter oct et pO ae das ei 22 45 Dynamic Linker Lt ERES E E diia 22 46 Dynamic Section oux Eur EE AUSREICHENDE M 22 47 Shared Object Dependencies 0 0 cece eee eee 22 52 Enk Map vols eta mesa ned ape Sead Sea REPE 22 53 Global Offset Table 0 0 0 0 cee eee eee 22 54 xvii Compilation Systems Volume 1 Tools Function Addresses eer ERU th see 22 57 Procedure Linkage Table seeeeeee eere 22 58 Hash Table zv A ke ENS PUO ENERO AB MEATUS 22 59 Initialization and Termination Functions 0 0000 cee eeeee 22 60 Symbolic Debugging Information 00 0 cee eee ee 22 61 Chapter 23 tdesc Information Intro ie a D e 23 1 AAA alse deii deer oeste ae bed 23 2 tdesc in Executable Programs and Shared Objects llle 00000005 23 10 EXAMPLES 2c A edt ea 23 13 Chapter 24 DWARF Debugging Information Format Introduction ip E ENS PES EARS 24 1 Purpose and Scope ooococoococc nent eens 24 2 OVeIVIeW cus eich ses x Sa Be uc ERIS ONT ST UE se 24 2 Vendor Extensibility lese 24 3 Changes from Version 1 1 0 drente ee 2
437. y cache misses or memory wait states since a static analysis cannot know if a memory reference will be in the cache or not Note that the C option does not circumvent this restriction The C option cannot provide a completely accurate model of the real cache because the simulation is not aware of other running processes nor of the operating system itself The purpose of this option is to provide a measure of the locality of a user program With the C option loads and stores that access multiple storage locations e g 1mw or stmw are treated as if they access only the first unit of storage Also if multiple consecutive accesses of a cache block occur only one miss is recorded In reality multiple misses might occur while the cache block is loading Finally conditional stores stwcx are assumed to always succeed For more detailed information on the hardware architectures refer to the following publications PowerPC User Instruction Set Architecture PowerPC 604 User s Manual The report tool reads the profile data generated by running a program which has been patched with the P option of the analyze tool report needs two arguments the name of the patched program generated by analyze and the name of the profile data file If the second argument is not specified it will append to the end of the first argument and look there for the profile data The printed reports are generated in a format that will conform with tools that
438. y tab o o S GET GFLAGS lt S YACC YFLAGS S C C C FLAGS SEM IP EIN rt mv y tab o o S LEX LFLAGS lt mv lex yy c S GET GFLAGS lt LEX LFLAGS mv lex yy c rm f L S LEX S LFLAGS lt C C C FLAGS ia IE AAS CANA O mv lex yy o On S GET S GFLAGS lt S LEX LFLAGS S C C C FLAGS NAS Ins 1t mv lex yy o EY zeuye Babe cae Hel WAC ONC cU ex yy L CHO VV 14 Tracking Versions with SCCS Introduction re eae Le 14 1 Basic Usage ie echec eret ku Lets 14 1 Terminology ove xen OF OO es RORIS MP USES RR nus NEA E M RS 14 1 Creating an SCCS File with admin 0 000000 eese 14 2 Retrieving a File with get llle 14 2 Recording Changes with delta llle 14 3 Morcon eet vc r ete ao EATUR UNS en NEE RUE EE ER io d 14 4 The help Command us 22 2 RERO TRE a 14 5 Delta Numbering oeeo ele RR RR ee ERREUR RE ERE 14 5 SCCS Command Conventions 0 0 0 000 ccc teen een nee 14 7 x hles and ZE sfc coe seco Rs A ESSE SARI e 14 8 Error Messages es ee ede ar SIMA ee 14 8 SCCS Commands ne re il 14 8 The get Command ee ke td eee eee ecce ge 14 9 ID Keywords esent ee eee Le E en CER 14 10 Retrieval of Different Versions 0 0 0 cece eee ees 14 10 To Update Source un sen ea MERO Ge RE 14 12 Undoing d get e ouk lo elo me ie e as 14 13 Additional get Options
439. yace input specification language is most naturally specified as an LR 2 grammar the sticky part comes when an identifier is seen in a rule immediately following an action If this identifier is followed by a colon it is the start of the next rule otherwise it is a continuation of the current rule which just happens to have an action embedded in it As implemented the lexical analyzer looks ahead after seeing an identifier and decides whether the next token skipping blanks new lines comments and so on is a colon If so it returns the token C IDENTIFIER Otherwise it returns IDENTIFIER Literals quoted strings are also returned as IDENTIFIERS but never as part of C IDENTIFI E RS grammar for the input to yacc basic entries IDENTIFIER C IDENTIFIER NUMBER js includes identifiers and literals identifier but not literal followed by a 0 9 reserved words type gt TYPE left gt LEFT etc LEFT RIGHT NONASSOC TOKEN PREC TYPE START UNION MARK Jot LCURL ES RCURL fits the ASCII character literals stand for themselves spec defs MARK rules tail MARK OREA TES act don eat up the rest of the file empty the second MARK is optional empty defs def START IDENTIFIER UNION Copy union definition to output LCURL Copy C code to output file RCURL rword tag nlist 7 29 Compilation Systems Volume I Tools
440. your executable only the object files in this archive that contain a function you have called in your program Note again that because we did not turn off the dynamic linking default with the Zlink static option the above command will direct the link editor to search 1ibc so as well as 1ibfoo a We ll look at the directory search option represented in the above command line by L dir in the next subsection For now it s enough to note that you use it to point the link editor to the directory in which your library is stored 4 11 Compilation Systems Volume 1 Tools 4 12 As mentioned earlier you create a shared object library by specifying the Zlink so option to the compiler cc Zlink so o libfoo so functionl o function2 o function3 o That command will create the shared object Libfoo so consisting of the object code for the functions contained in the named files We are deferring for the moment a discussion of a compiler option ZPIC that you should use in creating a shared object For that discussion see Implementation on page 4 17 When you use the 1 option to link your program with libfoo so cc L dir filel c file2 c file3 c lfoo the link editor will record in your executable the name of the shared object and a small amount of bookkeeping information for use by the system at run time Another component of the system the dynamic linker does the actual linking A number of things are worth pointing out
441. ype to a pointer to an object type with stricter alignment requirements may not be portable lint flags int fun y char ys return int y because on most machines an int cannot start on an arbitrary byte boundary whereas a char can If you suppress the diagnostic by invoking lint with h you may be disabling other messages You can eliminate the problem by using the generic pointer void ANSI C leaves the order of evaluation of complicated expressions undefined What this means is that when function calls nested assignment statements or the increment and decrement operators cause side effects when a variable is changed as a by product of the evaluation of an expression the order in which the side effects take place is highly machine dependent By default lint flags any variable changed by a side effect and used elsewhere in the same expression int a 10 main int 2 1 alit i 10 4 Analyzing Your Code with lint Note that in this example the value of a 1 may be 1 if one compiler is used 2 if another The bitwise logical operator amp can also give rise to this diagnostic when it is mistakenly used in place of the logical operator amp amp if c getchar EOF amp c 0 Suspicious Constructs lint flags a number of valid constructs that may not represent what the programmer intended Examples Anunsigned variable always has a nonnegative value So the test
442. ysical address Pnumber length Lnumber alignments Anumber There are three built in segments with the following default attribute values 4 25 Compilation Systems Volume 1 Tools text LOAD RX no virtual address physical address or length specified alignment values set to defaults per CPU type data LOAD RWX no virtual address physical address or length specified alignment values set to defaults per CPU type note NOTE ld behaves as if these segments had been declared before your mapfile is read in See Mapfile Option Defaults on page 4 30 for more information Note the following when entering segment declarations Anumber can be hexadecimal decimal or octal following the same rules as in the C language No space is allowed between the V P L or A and the number The segment type value can be either LOAD or NOTE The segment type value defaults to LOAD The segment flags values are R for readable W for writable and X for executable No spaces are allowed between the question mark and the individual flags that make up the segment flags value The segment flags value for a LOAD segment defaults to RWX NOTE segments cannot by assigned any segment attribute value other than a segment type Implicitly declared segments default to segment type value LOAD segment flags value RWX a default virtual address physical address and alignment value

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