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Red Hat Developer Toolset 1.x User Guide

1. To verify the version of g you are using at any point type the following at a shell prompt which g Red Hat Developer Toolset s g executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset g Ps EM gt v Some newer library features are statically linked into applications built with Red Hat Developer Toolset to support execution on multiple versions of Red Hat Enterprise Linux This adds a small additional security risk as normal Red Hat Enterprise Linux errata would not change this code If the need for developers to rebuild their applications due to such an issue arises Red Hat will signal this via a security erratum Developers are strongly advised not to statically link their entire application for the same reasons Example 2 3 Compiling a C Program on the Command Line Imagine that you have a source file named hello cpp with the following contents include lt iostream gt using namespace std int main int argc char argv cout lt lt Hello World lt lt endl return 0 To compile this source code on the command line by using the g compiler from Red Hat Developer Toolset type E scl enable devtoolset 1 1 g o hello hello cpp This creates a new binary file called hello in t
2. Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset Valgrind as default scl enable devtoolset 1 1 bash e u To verify the version of Valgrind you are using at any point type the following at a shell prompt which valgrind Red Hat Developer Toolset s valgrind executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset Valgrind valgrind version 8 3 Additional Resources A detailed description of Valgrind and its features is beyond the scope of this book For more information refer to the resources listed below Installed Documentation valgrind 1 The manual page for the valgrind utility provides detailed information on how to use Valgrind To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 1 1 man valgrind Valgrind Documentation HTML documentation for Valgrind is located at opt rh devtoolset 1 1 root usr share doc devtoolset 1 1 valgrind 3 8 1 html index html Online Documentation Hat Enterprise Linux 6 provides more detailed information about using Valgrind to profile applications See Also greatest amount of CPU tim
3. C 11 see GNU Compiler Collection c filt overview binutils C11 see GNU Compiler Collection Cachegrind Red Hat Developer Toolset 1 x User Guide 103 debugging see GNU Debugger Developer Toolset see Red Hat Developer Toolset documentation DRD elfedit eu ar 104 Revision History eu findtextrel overview elfutils eu make debug archive overview elfutils tils eu nm eu objdump overview elfutils eu ranlib overview elfutils eu size overview elfutils eu strings overview elfutils Red Hat Developer Toolset 1 x User Guide 105 eu strip eu unstrip overview elfutils feedback g see GNU Compiler Collection GAS see GNU assembler GCC see GNU Compiler Collection gcc see GNU Compiler Collection GDB see GNU Debugger gfortran see GNU Compiler Collection Global Support Services 106 Revision History installation Ir overview b gold see GNU linker gprof GSS see Global Support Services Helgrind help Id see GNU linker linking see GNU linker Massif overview Valgrind usage Using Valgrind Memcheck overview Valgrind usage Using Valgrind nm overview binutils usage Using Other Binary Tools objcopy features New Features Red Hat Developer Toolset 1 x User Guide 107 108 Revision History ophelp oprofiled ranlib overview binutils readelf Red Hat Developer Toolset
4. The info threads command now displays the thread name as set by prct1 or pthread setname np In addition new commands thread name and thread find have been added The thread name command accepts a name as an argument and can be used to set the name of the current thread The thread find command accepts a regular expression and allows SI O p M lat Developer Toolset 1 x User Guide T4 the user to find threads that match it GDB now provides support for reading and writing a new gdb_index section The command gdb add index can be used to add gdb index to a file which allows GDB to load symbols from that file faster Note that this feature is already present in Red Hat Enterprise Linux 6 1 and later The watch command has been adapted to accept Location as an optional argument Two new special values can now be used when specifying the current search path for libthread_db sdir represents the default system locations of shared libraries and pdir stands for the directory with the libthread that is used by the application A new command info macros has been added This command accepts linespec as an optional argument and can be used to display the definitions of macros at that linespec location Note that in order to do this the debugged program must be compiled with the g3 command line option to have macro information available in it A new command alias has been added This command can be used to create an alias of
5. break file name line_ number You can also set a breakpoint on a certain function break file name function name Example 3 5 Setting a New Breakpoint 10 by running the following command gdb break 10 Breakpoint 1 at 0x4004e5 file fibonacci c line 10 Listing Breakpoints To display a list of currently set breakpoints run the following command info breakpoints Example 3 6 Listing Breakpoints display the list of currently set breakpoints by running the following command gdb info breakpoints Num Type Disp Enb Address What 1 breakpoint keep y 0x00000000004004e5 in main at fibonacci c 10 Deleting Existing Breakpoints To delete a breakpoint that is set at a certain line run the following command clear line number Similarly to delete a breakpoint that is set on a certain function run clear function name You can also delete all breakpoints at once To do so run the clear command with no additional arguments clear Red Hat Developer Toolset 1 x User Guide 33 Example 3 7 Deleting an Existing Breakpoint Imagine that you have accidentally set a breakpoint at a wrong line and you want to remove it 7 by running the following command gdb break 7 Breakpoint 2 at 0x4004e3 file fibonacci c line 7 To remove this breakpoint type gdb clear 7 Deleted breakpoint 2 3 6 Starting Execution To start execution of the program you are debugging run the following command run If the progr
6. gfortran 1 The manual page for the gfortran compiler provides detailed information on its usage To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 1 1 man gfortran C Standard Library Documentation Documentation on the C standard library can be optionally installed by typing the following at a shell prompt as root yum install devtoolset 1 1 libstdc docs Once installed HT ML documentation is available at opt rh devtoolset 1 1 root usr share doc devtoolset 1 1 libstdc docs 4 7 2 html index html Online Documentation information on gfortran s usage See Also over the Red Hat Enterprise Linux system version of the GNU Compiler Collection as well as information about the language ABI and debugging compatibility Red Hat Developer Toolset 1 x User Guide 27 describes how to use it with the tools from Red Hat Developer Toolset 28 Chapter 3 GNU Debugger GDB Chapter 3 GNU Debugger GDB The GNU Debugger commonly abbreviated as GDB is a command line tool that can be used to debug programs written in various programming languages It allows you to inspect memory within the code being debugged control the execution state of the code detect the execution of particular sections of code and much more Red Hat Developer Toolset is distributed with GDB 7 5 This version is more recent than the version included in Red Hat Enterprise Linux and provid
7. application for the same reasons Example 2 5 Compiling a Fortran Program on the Command Line Imagine that you have a source file named hello f with the following contents program hello print Hello World end program hello To compile this source code on the command line by using the gfortran compiler from Red Hat Developer Toolset type scl enable devtoolset 1 1 gfortran o hello hello f This creates a new binary file called hello in the current working directory 2 3 3 Running a Fortran Program When gfortran compiles a program it creates an executable binary file To run this program on the command line change to the directory with the executable file and type file name S 26 Chapter 2 GNU Compiler Collection GCC Example 2 6 Running a Fortran Program on the Command Line prompt hello Hello World 2 4 Additional Resources A detailed description of the GNU Compiler Collections and its features is beyond the scope of this book For more information refer to the resources listed below Installed Documentation gcc 1 The manual page for the gcc compiler provides detailed information on its usage with few exceptions g accepts the same command line options as gcc To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 1 1 man gcc
8. type scl enable devtoolset 1 1 gcc g o fibonacci fibonacci c This creates a new binary file called fibonacci in the current working directory Installing Debugging Information for Existing Packages To install debugging information for a package that is already installed on the system type the following at a shell prompt as root debuginfo install package_name Note that the yum utils package must be installed for tte debuginfo install utility to be available on your system Example 3 2 Installing Debugging Information for the glibc Package To install debugging information for the glibc package type debuginfo install glibc Loaded plugins product id refresh packagekit subscription manager gt Running transaction check gt Package glibc debuginfo x86 64 0 2 12 1 47 e16 2 5 will be installed 3 3 Running the GNU Debugger 30 Chapter 3 GNU Debugger GDB To run the GNU Debugger on a program you want to debug type the following at a shell prompt scl enable devtoolset 1 1 gdb file name This starts the gdb debugger in interactive mode and displays the default prompt gdb To quit the debugging session and return to the shell prompt run the following command at any time quit Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a she
9. which enables the user to control the maximum size of inlined memcpy calls and similar B 2 Changes in GDB 7 5 Red Hat Developer Toolset 1 1 is distributed with GDB 7 5 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system versions Below is a comprehensive list of new features in this release For details on how to use these new features refer to the GDB The following features have been added since the release of the GNU Debugger versions included in Red Hat Enterprise Linux 6 3 and 5 9 The info os command has been changed and can now display information on several objects managed by the operating system in particular The info os procgroups command lists process groups The info os files command lists file descriptors The info os sockets command lists internet domain sockets The info os shm command lists shared memory regions The info os semaphores command lists semaphores The info os msg command lists message queues The info os modules command lists loaded kernel modules GDB now has support for Static Defined Tracing SDT probes Currently the only implemented back end is for SystemT ap probes the sys sdt h header file You can set a breakpoint by using the new probe pstap or probe stap options and inspect the probe arguments by using the new probe arg family of convenience variables The symbol reloading option has been deleted gdbserver now supports STDIO c
10. with __ sync are still supported Transactional Memory Transactional Memory TM allows programs to declare that a piece of code is supposed to execute as a transaction that is virtually atomically and in isolation from other transactions GCC s transactional memory runtime library libitm then ensures this atomicity guarantee when executing the compiled program Compared to atomic memory accesses it is a higher level programming abstraction because it is not limited to single memory locations does not require special data types for the data it modifies and because transactions can contain arbitrary code and be nested within other transactions with some restrictions explained subsequently already supports a C compatible subset of the constructs when compiling C source code The main language constructs are transaction statements and expressions and are declared by the transaction atomicor transaction relaxed keywords followed by a compound statement or expression respectively The following example illustrates how to increment a global variable y if another variable x has a value less than 10 transaction atomic if x lt 10 yt This happens atomically even in a multi threaded execution of the program In particular even though the transaction can load x and y and store to y all these memory accesses are virtually executed as one indivisible step Red Hat Developer Toolset 1 x User Guide 69 Note that in line with t
11. 1 1 3 Parallelism and Concurrency GCC 4 7 provides improved support for programming parallel applications 1 The GCC compilers support the OpenMP API specification for parallel programming version 3 1 2 The C 11 and C11 standards provide programming abstractions for multi threaded programs The respective standard libraries include programming abstractions for threads and thread related features such as locks condition variables or futures These new versions of the standard also define a memory model that precisely specifies the runtime behavior of a multi threaded program such as the guarantees provided by compilers and the constraints programmers have to pay attention to when writing multi threaded programs Note that support for the memory model is still experimental see below for details For more 68 Changes in Version 1 0 C 11 and The rest of this section describes two new GCC features in more detail Both these features make it easier for programmers to handle concurrency such as when multiple threads do not run truly in parallel but instead have to synchronize concurrent access to shared state and both provide atomicity for access to memory but differ in their scope applicability and complexity of runtime support C 11 Types and GCC Built ins for Atomic Memory Access C 11 has support for atomic types Access to memory locations of this type is atomic and appears as one indivisible access even when other
12. 1 gcc c 2 2 2 Using the C Compiler To compile a C program on the command line run the g compiler as follows scl enable devtoolset 1 1 g o output file source file This creates a binary file named output file in the current working directory If the o option is omitted the g compiler creates a file named a out by default When you are working on a project that consists of several source files it is common to compile an object file for each of the source files first and then link these object files together This way when you change a single source file you can recompile only this file without having to compile the entire project To compile an object file on the command line run the following command scl enable devtoolset 1 1 g o object file c source file This creates an object file named object_file If the o option is omitted the g compiler creates a file named after the source file with the o file extension To link object files together and create a binary file run scl enable devtoolset 1 1 g o output file object file Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset g as default scl enable devtoolset 1 1 bash Red Hat Developer Toolset 1 x User Guide 23 rraau
13. 1 x User Guide 73 error truncate was not declared in this scope error sleep was not declared in this scope error pipe was not declared in this scope error there are no arguments to offsetof that depend on a template parameter so a declaration of offsetof must be available To fix this add the following line early in the source or header files that need it include lt unistd h gt Many of the standard C library include files have been edited to no longer include lt cstddef gt to get namespace std scoped versions of size_t and ptrdiff_t As such C programs that used the macros NULL or of fsetof without including lt cstddef gt will no longer compile The diagnostic produced is similar to the following error ptrdiff t does not name a type error size t has not been declared error NULL was not declared in this scope error there are no arguments to offsetof that depend on a template parameter so a declaration of offsetof must be available To fix this issue add the following line include lt cstddef gt Name Lookup Changes G no longer performs an extra unqualified lookup that it incorrectly performed in the past Instead it implements the two phase lookup rules correctly and an unqualified name used in a template must have an appropriate declaration that 1 is either in scope at the point of the template s definition or 2 can be found by argument dependent lookup at the point of instan
14. 32 bit and 64 bit Intel and AMD architectures and supports only C and C development The Red Hat Enterprise Linux 6 version does not provide support for the Fortran programming language 10 2 Running Eclipse To start Eclipse with support for the GNU Compiler Collection and GNU Debugger from Red Hat Developer Toolset type the following at a shell prompt scl enable devtoolset 1 1 eclipse This invokes the Red Hat Enterprise Linux Eclipse IDE using the Developer Toolset gcc compiler and gdb debugger instead of the Red Hat Enterprise Linux system equivalents If you are working on a project that you previously built with the Red Hat Enterprise Linux version of the GNU Compiler Collection make sure that you discard all previous build results To do so open the project in Eclipse and select Project Clean from the menu You can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalents This allows you to run a shell session with Red Hat Developer Toolset gcc and gdb as the default compiler and debugger for Eclipse scl enable devtoolset 1 1 bash rrammm To verify the version of gcc you are using at any point type the following at a shell prompt EERUNUIEMGI LES o SO which gcc Red Hat Developer Toolset s gcc executable path
15. Hat Developer Toolset to support execution on multiple versions of Red Hat Enterprise Linux This adds a small additional security risk as normal Red Hat Enterprise Linux errata would not change this code If the need for developers to rebuild their applications due to such an issue arises Red Hat will signal this via a security erratum Developers are strongly advised not to statically link their entire application for the same reasons Example 2 1 Compiling a C Program on the Command Line Imagine that you have a source file named hello c with the following contents IE Tae Ts m DN include lt stdio h gt int main int argc char argv printf Hello World n return 0 To compile this source code on the command line by using the gcc compiler from Red Hat Developer Toolset type E scl enable devtoolset 1 1 gcc o hello hello c This creates a new binary file called hello in the current working directory 2 1 3 Running a C Program When gcc compiles a program it creates an executable binary file To run this program on the command line change to the directory with the executable file and type ri SITS file name 22 Chapter 2 GNU Compiler Collection GCC Example 2 2 Running a C Program on the Command Line hello Hello World 2 2 GNU C Compiler 2 2 1 Installing the C Compiler In Red Hat Developer Toolset the GNU C compiler is provided by the devtoolset 1
16. Object ref iniCtx lookup EchoBean EchoHome home EchoHome ref Echo echo home create System out println Created Echo System out println Echo echo Hello echo echo Hello 1 3 Notes and Warnings Finally we use three visual styles to draw attention to information that might otherwise be overlooked Notes are tips shortcuts or alternative approaches to the task at hand Ignoring a note should have no negative consequences but you might miss out on a trick that makes your life easier Important boxes detail things that are easily missed configuration changes that only apply to the current session or services that need restarting before an update will apply Ignoring a box labeled Important will not cause data loss but may cause irritation and frustration Warnings should not be ignored Ignoring warnings will most likely cause data loss 2 Getting Help and Giving Feedback 2 1 Do You Need Help If you experience difficulty with a procedure described in this documentation visit the Red Hat Customer gt search or browse through a knowledgebase of technical support articles about Red Hat products submit a support case to Red Hat Global Support Services GSS access other product documentation Red Hat also hosts a large number of electronic mailing lists for discussion of Red Hat software and 9 10 Preface Click on the name of any mailing list to subscribe to that list or to access
17. Stories CONNECT Product Documentation Reference Architectures Evaluations amp Demos Certified Hardware Figure 12 1 The Plan Menu In the Plan menu are resources needed to plan a development project These menu items provide proven resources to implement the best solution the first time This includes Webinars The Webinars page contains information on upcoming Red Hat and open source events around the world Here you can register for upcoming webinars or watch archived ones on demand Success Stories Read the success stories of other Red Hat customers to learn how leading organizations are finding unbeatable value performance security and reliability with Red Hat solutions Product Documentation This provides a list of links to the various Red Hat documents including books for Red Hat Enterprise Linux Identity Management and Infrastructure Red Hat Enterprise Storage JBoss Enterprise Middleware and System Management Reference Architectures Reference Architectures contains a list of whitepapers that detail technical case studies of solutions that have been built tested and bench marked by senior Red Hat engineers They explain the capabilities and limitations of a given solution as well as detailed notes on how to implement the solution Evaluations amp Demos You can download free evaluations of various Red Hat products from here including Red Hat Enterprise Linux Red Hat Enterprise Virtualizat
18. The behavior of the cg annotate s rarely used threshold option has been changed Callgrind now supports branch prediction simulation and can optionally count the number of executed global bus events Note that in order to use this functionality for a better approximation of a Cycle Estimation as a derived event you must manually update the event formula in KCachegrind To accommodate machines with three levels of caches both Cachegrind and Callgrind now refer to the LL last level cache rather than the L2 cache When Cachegrind or Callgrind auto detects the cache configuration of such a machine it now runs the simulation as if the L2 cache is not present Consequently the results are less likely to match the true result for the machine and should not be considered authoritative but provide a general idea about a program s locality A new command line option pages as heap has been added to Massif When this option is enabled Massif tracks memory allocations at the level of memory pages as mapped by mmap brk and similar functions instead of tracking allocations at the level of heap blocks as allocated with malloc new or new Each mapped page is treated as its own block Interpreting the page level output is harder than the heap level output but allows you to account for every byte of memory used by a program By default the pages as heap option is disabled New command line options free is write and trace alloc have been ad
19. an existing command The info macro command now accepts all and as valid options To display a function parameter s entry value that is the value at the time of function entry the suffix entry can be added to the parameter GDB now displays entry values in backtraces if available New set print entry values and show print entry values commands have been added The set print entry values command accepts both compact default if needed no only and preferred as valid arguments and can be used to enable printing of function arguments at function entry The show print entry values command can be used to determine whether this feature is enabled New set debug entry values and show debug entry values commands have been added The set debug entry values command can be used to enable printing of debugging information for determining frame argument values at function entry and virtual tail call frames command has been added as an alias of shell command The watch command now accepts mask mask value as an argument This can be used to create masked watchpoints New set extended prompt and show extended prompt commands have been added The set extended prompt command enables support for a defined set of escape sequences that can be used to display various information The show extended prompt command can be used to determine whether the extended prompt is enabled New set basenames may differ and show basenames may differ commands have be
20. arguments denoting an absent argument Non pointer variables with the TARGET attribute can now be used as an actual argument to POINTER dummies with INTENT IN Pointers that include procedure pointers and those in a derived type pointer components can now also be initialized by a target instead of only by NULL The EXIT statement with construct name can now be used to leave the ASSOCIATE BLOCK IF SELECT CASE and SELECT TYPE constructs in addition to DO Internal procedures can now be used as actual arguments The named constants INTEGER_KINDS LOGICAL_KINDS REAL_KINDS and CHARACTER_KINDS of the intrinsic module ISO_FORTRAN_ENV have been added These arrays contain the supported kind values for the respective types The C_SIZEOF module procedures of the ISO_C_BINDINGS intrinsic module and the COMPILER_VERSION and COMPILER_OPTIONS module procedures of the ISO_FORTRAN_ENV intrinsic module have been implemented The OPEN statement now supports the NEWUNIT option This option returns a unique file unit and therefore prevents inadvertent use of the same unit in different parts of the program Unlimited format items are now supported The INT 8 16 32 and REAL 32 64 128 format for ISO_FORTRAN_ENV intrinsic module type parameters are now supported It is now possible to use complex arguments with the TAN SINH COSH TANH ASIN ACOS and AT AN functions Additionally the new functions ASINH ACOSH and AT ANH have been added for re
21. been added since the release of OProfile included in Red Hat Enterprise Linux 5 9 Support has been added for AMD family11h family12h family14h and AMD family15h processors Generation of XML output has been corrected Handling of the session dir command line option has been improved and a possible buffer overflow in the XML generator has been fixed Red Hat Developer Toolset 1 x User Guide 101 Revision History Revision 1 1 0 Tue Jan 22 2013 Jaromir Hradilek Red Hat Developer Toolset 1 1 release of the User Guide Revision 1 0 2 Fri Nov 09 2012 Jaromir Hradilek Red Hat Developer Toolset 1 1 Beta 2 release of the User Guide Revision 1 0 1 Wed Oct 10 2012 Jaromir Hradilek Red Hat Developer Toolset 1 1 Beta 1 release of the User Guide Revision 1 0 0 Tue Jun 26 2012 Jaromir Hradilek Red Hat Developer Toolset 1 0 release of the User Guide Revision 0 0 2 Tue May 22 2012 Jarom r Hrad lek Red Hat Developer Toolset 1 0 Beta 2 release of the User Guide Revision 0 0 1 Tue May 1 2012 Jarom r Hrad lek Red Hat Developer Toolset 1 0 Beta 1 release of the User Guide Revision 0 0 0 Mon Apr 23 2012 Jarom r Hrad lek Initial creation of the book by Publican Index ABI compatibility ABI Compatibility addr2line features New Features application binary interface see ABI ar overview binutils usage as see GNU assembler assembling see GNU assembler bfd features New Features 102 Revision History
22. debugging a loop you can run the continue command in the following form continue number The gdb utility also allows you to stop the execution after executing a single line of code To do so run step Finally you can execute a certain number of lines by using the step command in the following form step number Red Hat Developer Toolset 1 x User Guide 35 Example 3 10 Continuing the Execution of the fibonacci Binary File and the execution of the fibonacci binary stopped after reaching the breakpoint at line 10 you can resume the execution by running the following command gdb continue Continuing Breakpoint 1 main argc 1 argv 0x7fffffffe4d8 at fibonacci c 10 10 printf ld b The execution stops the next time the breakpoint is reached To execute next three lines of code type gdb step 3 13 b sum This allows you to verify the current value of the sum variable before it is assigned to b gdb print sum 3 2 3 9 Additional Resources A detailed description of the GNU Debugger and all its features is beyond the scope of this book For more information refer to the resources listed below Online Documentation reference material See Also describes how to use it with the tools from Red Hat Developer Toolset 36 Chapter 4 binutils Chapter 4 binutils binutils is a collection of various binary tools such as the GNU linker GNU assembler and other with the Red Hat Developer Toolset ve
23. default The prior default setting can be chosen by using the fno omit frame pointer command line option Floating point calculations on x86 targets and in strict C99 mode are now compiled by GCC with a stricter standard conformance This might result in those calculations executing significantly slower It can be disabled using fexcess precision fast 78 Changes in Version 1 0 A 1 4 Debugging Compatibility GCC now generates DWARF debugging information that uses more or newer DWARF features than previously GDB contained in the Developer Toolset can handle these features but versions of GDB older than 7 0 cannot GCC can be restricted to only generate debugging information with older DWARF features by using the gdwarf 2 gstrict dwarf or gdwarf 3 gstrict dwarf options the latter are handled partially by versions of GDB older than 7 0 Many tools such as Valgrind SystemTap or third party debuggers utilize debugging information It is suggested to use the gdwarf 2 gstrict dwarf options with those tools rraauA A Use of Link time Optimization with debug generation is not yet supported in gcc 4 7 and so use of the flto and the g options together is unsupported in Developer Toolset A 1 5 Other Compatibility GCC is now more strict when parsing command line options and both gcc and g report an error when invalid command line options are used In particular when only linking and not compiling code e
24. if the you have forgotten to mark the pool superblock noaccess The performance of Memcheck s memory leak check has been improved The improvement is especially significant in cases where there are many leaked blocks or many suppression rules used to suppress leak reports Vore facilities that can help finding the cause of a data race have been added to DRD namely the Changes in Version 1 1 ptrace addr command line option and the DRD_STOP_TRACING_VAR x macro The C demangler has been updated to support C programs compiled by g up to at least version 4 6 A new command line option fair sched yes has been added This option allows you to select round robin scheduling of threads improves responsiveness of interactive multithreaded applications and improves repeatability of results from the thread checkers Helgrind and DRD The pipe based thread serialization mechanism is selected by default Support for running Valgrind on Valgrind has been improved Tool developers can now use Valgrind on Helgrind or Memcheck gdbserver has been adapted to display the float shadow registers as integer rather than float values as the shadow values are mostly used as bit patterns The maximum limit for the num callers command line option has been increased to 500 The performance of error matching when there are many suppression records in use has been improved Support for DWARF4 debugging information has been improved Support for D
25. of the specification of the language constructs or due to implementation requirements Note that when executing applications built with the gnu tm command line option it is currently a prerequisite to also have the appropriate version of the libitm so 1 shared library installed Refer to the Guidance on Experimental Features in gcc version 4 7 0 section in the Red Hat Developer Toolset 1 0 Release Notes for more information A 1 1 4 Architecture specific Options Red Hat Developer Toolset 1 0 is only available for Red Hat Enterprise Linux 5 and 6 both for the 32 bit and 64 bit Intel and AMD architectures Consequently the options described below are only relevant to these architectures Optimization for several processors is now available through the command line options described in Table A 1 Processor Optimization Options Option Description march core2 and mtune core2 Optimization for Intel Core 2 processors march corei7 and mtune corei7 Optimization for Intel Core i3 ib and i7 processors march corei7 avx and mtune corei7 Optimization for Intel Core i3 ib and i7 avx processors with AVX marchzcore avx i Optimization for the Intel processor code named Ivy Bridge with RDRND FSGSBASE and F16C march core avx2 Optimization for a next generation processor from Intel with AVX2 FMA BMI BMI2 and LZ CNT march bdver2 and mtune bdver2 Optimization for AMD family 15h processors code named Piledriver marc
26. the Wnarrowing option A 1 3 ABI Compatibility This section describes compatibility between the Red Hat Developer Toolset compilers and the system Red Hat Developer Toolset 1 x User Guide 77 compilers on the application binary interface ABI level A 1 3 1 C ABI Because the upstream GCC community development does not guarantee C 11 ABI compatibility across major versions of GCC the same applies to use of C 11 with Red Hat Developer Toolset Consequently using the std c 11 option is supported in Red Hat Developer Toolset 1 0 only when all C objects compiled with that flag have been built using the same major version of Red Hat Developer Toolset The mixing of objects binaries and libraries built by the Red Hat Enterprise Linux 5 or 6 system toolchain GCC using the std c 0x or std gnu 0x flags with those built with the std c 11 or std gnu 11 flags using the GCC in Red Hat Developer Toolset is explicitly not supported As later major versions of Red Hat Developer Toolset may use a later major release of GCC forward compatibility of objects binaries and libraries built with the std c 11 or std gnu 11 options cannot be guaranteed and so is not supported The default language standard setting for Red Hat Developer Toolset is C 98 Any C 98 compliant binaries or libraries built in this default mode or explicitly with std c 98 can be freely mixed with binaries and shared libraries built by the Red Hat Enterpri
27. the list archives 2 2 We Need Feedback If you find a typographical error in this manual or if you have thought of a way to make this manual against the product Red Hat Developer Toolset When submitting a bug report be sure to mention the manual s identifier doc User Guide If you have a suggestion for improving the documentation try to be as specific as possible when describing it If you have found an error please include the section number and some of the surrounding text so we can find it easily Red Hat Developer Toolset 1 x User Guide 11 Part I Introduction 12 Chapter 1 Red Hat Developer Toolset Chapter 1 Red Hat Developer Toolset 1 1 About Red Hat Developer Toolset Red Hat Developer Toolset is a Red Hat offering for developers on the Red Hat Enterprise Linux platform and provides a complete set of development and performance analysis tools that can be installed and used on multiple versions of Red Hat Enterprise Linux Executables built with the Red Hat Developer Toolset toolchain can then also be deployed and run on multiple versions of Red Hat Critically Red Hat Developer Toolset does not replace the default system tools provided with Red Hat Enterprise Linux 5 or 6 when installed on those platforms Instead a parallel set of developer tools provides an alternative newer version of those tools for optional use by developers The default compiler and debugger for example remain those provided by the base Red
28. time with very large C applications In Red Hat Developer Toolset the gold linker is not enabled by default Users can explicitly switch between 1d and gold by using the alternatives mechanism A 3 1 1 New Features Changes Since Red Hat Enterprise Linux 6 2 The following features have been added since the release of binutils included in Red Hat Enterprise Linux 6 2 A new INPUT SECTION FLAGS keyword has been added to the linker script language This keyword can be used to select input sections by section header flags A new SORT BY INIT PRIORITY keyword has been added to the linker script language This keyword can be used to sort sections by numerical value of the GCC init priority attribute encoded in the section name Changes Since Red Hat Enterprise Linux 5 8 In addition to the above changes the following features have been added since the release of the binutils included in Red Hat Enterprise Linux 5 8 GNU Linux targets now support the STB GNU UNIQUE symbol binding a GNU extension to the standard set of ELF symbol bindings The binding is passed on to the dynamic linker which ensures that in the entire process there is only one symbol with the given name and type in use rrxmEEK The implementation of this feature depends on capabilities only found in newer versions of the glibc library Consequently this feature is currently available in Red Hat Developer Toolset for Red Hat Enterprise Linux 6 A new c
29. to the GCC documentation A 1 1 Status and Features A 1 1 1 C 11 GCC 4 7 provides experimental support for building applications compliant with C 11 using the std c 11 or std gnu 11 command line options However there is no guarantee for compatibility for details The C runtime library libstdc supports a majority of the C 11 features However there is no or only partial support for some features such as certain properties on type traits or regular defined behavior Support for C 11 exception ptr and future requires changes to the exception handling runtime in the system libstdc package These changes will be distributed through the normal Z stream channel Refer to the Guidance on Experimental Features in gcc version 4 7 0 section in the Red Hat Developer Toolset 1 0 Release Notes for more information A 1 1 2 C11 GCC 4 7 provides experimental support for some of the features from the C11 revision of the ISO C standard and in addition to the previous now deprecated std c1x and std gnu1x command line options gcc now accepts std c11 and std gnu11 Note that since this support is experimental it may change incompatibly in future releases Examples for features that are supported are Unicode strings including the predefined macros STDC UTF 16 and STDC UTF 32 J nonreturning functions Noreturn and lt stdnoreturn h gt and alignment support Alignas Alignof max align t and lt stdalign h gt A
30. version of the Red Hat Enterprise Linux host EUS 6 1 O O O 8 O O9O EUS 6 2 EUS 6 3 6 4 e Unsupported o Supported 1 4 Getting Access to Red Hat Developer Toolset Red Hat Developer Toolset is an offering that is distributed as part of the developer subscriptions listed management service with which you registered your Red Hat Enterprise Linux system you can either enable Red Hat Developer Toolset by using the Red Hat Subscription Management or by using RHN Classic For detailed instructions on how to enable Red Hat Developer Toolset using RHN Classic or Red Hat Subscription Management refer to the respective section below For information on how to register your system with one of these subscription management services see the Red Hat Subscription Management Guide Important If you are running a version of Red Hat Enterprise Linux prior to 5 9 or 6 4 you will be unable to download Red Hat Developer Toolset through Red Hat Subscription Management To obtain Red Hat Developer Toolset you will need to either update to Red Hat Enterprise Linux 5 9 or 6 4 or register your system with RHN Classic For more information refer to Red Hat Developer Toolset 1 x User Guide 15 Table 1 2 Subscriptions that provide Red Hat Developer Toolset SKU Subscription Name RH2282403 Red Hat Enterprise Linux Developer Support Professional RH2264664 Red Hat Enterprise Linux Developer Support Enterprise RH2262474 Red Hat Enterp
31. 1 x User Guide 109 scl see Software Collections size overview binutils stap staprun 110 Revision History stapsh strings strip V
32. 5 Issue Severity Determining an issue s severity is important to allow the GSS team to prioritize their work There are four levels of severity Severity 1 urgent A problem that severely impacts your use of the software for production purposes It halts your business operations and has no procedural work around Severity 2 high A problem where the software is functioning but production is severely reduced It causes a high impact to business operations and no work around exists Severity 3 medium A problem that involves partial non critical loss of the use of the software There is a medium to low impact on your business and business continues to function by utilizing a work around Severity 4 low A general usage question report of a documentation error or a recommendation for a future product improvement For more information on determining the severity level of an issue refer to that you need your Red Hat login details in order to submit service requests If the severity is level 1 or 2 then follow up your service request with a phone call Contact information If you have a premium subscription then after hours support is available for Severity 1 and 2 cases Turn around rates for both premium subscriptions and standard subscription can be found at 13 2 Escalating an Issue If you feel as though an issue is not being handled correctly or adequately you can escalate it There are two types of escalation Technica
33. Changes in Version 1 1 This appendix documents new features and compatibility changes introduced in Red Hat Developer Toolset 1 1 For a complete list of changes that were introduced in the previous version of the product B 1 Changes in GCC 4 7 2 Red Hat Developer Toolset 1 1 is distributed with GCC 4 7 2 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version The main change in this version compared to Red Hat Developer Toolset 1 0 is that Fortran development is now supported Additionally support for Fortran 2003 and 2008 has been significantly improved relative to the GCC versions shipped with Red Hat Enterprise Linux see details below B 1 1 C 11 Compatibility previously published for Red Hat Developer Toolset 1 0 This change is included by default in Red Hat Developer Toolset 1 1 Consequently any C 11 code compiled with the Red Hat Developer Toolset 1 0 version of GCC before applying the erratum might be incompatible with C 11 code compiled by the Red Hat Developer Toolset 1 1 version There is no change in the C 11 ABI between Red Hat Developer Toolset 1 0 with erratum RHBA 2012 1127 applied and Red Hat Developer Toolset 1 1 B 1 2 Fortran B 1 2 1 New Features A new compile flag fstack arrays has been added This flag causes all local arrays to be put on stack memory which can significantly improve the performance of some programs Note that programs that use ver
34. Display a list of available Yum repositories to retrieve repository metadata and to determine the exact name of the Red Hat Developer Toolset repositories As root type yum repolist all The repository names depend on the specific version of Red Hat Enterprise Linux you are using and are in the following format rhel variant dts version rpms rhel variant dts version debug rpms rhel variant dts version source rpms Replace variant with the Red Hat Enterprise Linux system variant server or workstation and version with the Red Hat Enterprise Linux system version 5 or 6 4 Enable the appropriate repository On Red Hat Enterprise Linux 6 you can do so by running the following command as root yum config manager enable repository On Red Hat Enterprise Linux 5 which does not support the yum config manager tool edit the etc yum repos d redhat repo file locate the relevant repository section and set the value of the enabled option to 1 enabled 1 Once the subscription is attached to the system you can install Red Hat Developer Toolset as your system using Red Hat Subscription Management and associate it with subscriptions refer to the Red Hat Subscription Management Guide 1 5 Installing Red Hat Developer Toolset Red Hat Developer Toolset is distributed as a collection of RPM packages To install the tools and libraries provided by Red Hat Developer Toolset ensure that the system is associated with an the devtoo
35. Fortran main program and is invoked by the main function which is now generated and put in the same object file as MAIN__ Note that the libgfortranbegin library is still present for backward compatibility B 1 2 3 Fortran 2003 Features Improved but still experimental support for polymorphism between libraries and programs and for complicated inheritance patterns Generic interface names which have the same name as derived types are now supported which allows the creation of constructor functions Note that Fortran does not support static constructor functions only default initialization or an explicit structure constructor initialization are available Automatic re allocation In intrinsic assignments to allocatable variables the left hand side will be automatically allocated if unallocated or reallocated if the shape or type parameter is different To Red Hat Developer Toolset 1 x User Guide 91 avoid the small performance penalty you can use a instead ofa for arrays and character strings or disable the feature using std f95 or fno realloc lhs Experimental support of the ASSOCIATE construct has been added In pointer assignments it is now possible to specify the lower bounds of the pointer and for a rank 1 or a simply contiguous data target to remap the bounds Deferred type parameter For scalar allocatable and pointer variables the character length can now be deferred Namelist variables with allocatable
36. Hat Developer Toolset 1 x User Guide 41 Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset binary tools as default scl enable devtoolset 1 1 bash rraaA To verify the version of elfutils you are using at any point type the following at a shell prompt which eu objdump Red Hat Developer Toolset s eu obj dump executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset eu obj dump eu objdump V 5 3 Additional Resources A detailed description of elfutils is beyond the scope of this book For more information refer to the resources listed below See Also in C C and Fortran 42 Chapter 6 dwz Chapter 6 dwz dwz is a command line tool that attempts to optimize DWARF debugging information contained in ELF shared libraries and ELF executables for size To do so dwz replaces DWARF information representation with equivalent smaller representation where possible and reduces the amount of duplication by using techniques from Appendix E of the DWARF Standard Red Hat Developer Toolset is distributed with dwz 0 7 6 1 Installing dwz In Red Hat Developer Toolset the dwz utility is provided by the devtoolset 1 1 dwz package and is 6 2 Using dwz To optimize DWARF debug
37. Hat Enterprise Linux system Red Hat Enterprise Linux in two important respects Red Hat Developer Toolset can be used on multiple major and minor releases of Red Hat Enterprise Unlike Technology Preview compilers and other tools shipped in earlier Red Hat Enterprise Linux Red Hat Developer Toolset is fully supported under Red Hat Enterprise Linux Subscription Level Agreements is functionally complete and is intended for production use Important bug fixes and security errata will be issued to Red Hat Developer Toolset subscribers in a similar manner to Red Hat Enterprise Linux for two years from the release of each major version release New major versions of Red Hat Developer Toolset will be released annually providing significant updates for existing components and adding major new components A single minor release issued six months after each new major version release will provide a smaller update of bug fixes security errata and new minor components Additionally the Red Hat Enterprise Linux Application Compatibility Specification also applies to Red Hat Developer Toolset subject to some constraints on the use of newer C 11 language features detailed PP important _1_1_1_ _lrlrl_llHta kr1krtl1 r r Applications and libraries provided by Red Hat Developer Toolset do not replace the Red Hat Enterprise Linux system versions nor are they used in preference to the system versions Using a framework called Software C
38. Here destruct does not race with potential concurrent uses of the data because after the transaction finishes itis guaranteed that data public is false and thus data is private See the specification and the C 11 memory model for more background information about this Note that even if transactions are required to virtually execute in a total order this does not mean that they execute mutually exclusive in time Transactional memory implementations attempt to run transactions as much in parallel as possible to provide scalable performance There are two variants of transactions atomic transactions transaction atomic and relaxed transactions transaction relaxed The former guarantee atomicity with regard to all other code but allow only code that is known to not include nontransactional kinds of synchronization such as atomic or volatile memory access In contrast relaxed transactions allow all code for example calls to I O functions but only provide atomicity with regard to other transactions Therefore atomic transactions can be nested within other atomic and relaxed transactions but relaxed transactions can only be nested within other relaxed transactions Furthermore relaxed transactions are likely to be executed with less performance but this depends on the implementation and available hardware GCC verifies these restrictions statically at compile time for example the requirements on code allowed to be called from within atom
39. Red Hat Developer Toolset 1 1 User Guide Installing and Using Red Hat Developer Toolset Edition 1 n3 redhat Jarom r Hrad lek Red Hat Engineering Content Services Jacquelynn East Red Hat Engineering Content Services Matt Newsome Red Hat Software Engineering mnewsome redhat com 2 Legal Notice Legal Notice Copyright 2012 2013 Red Hat Inc The text of and illustrations in this document are licensed by Red Hat under a Creative Commons Attribution Share Alike 3 0 Unported license CC BY SA An explanation of CC BY SA is available at document or an adaptation of it you must provide the URL for the original version Red Hat as the licensor of this document waives the right to enforce and agrees not to assert Section Ad of CC BY SA to the fullest extent permitted by applicable law Red Hat Red Hat Enterprise Linux the Shadowman logo JBoss MetaMatrix Fedora the Infinity Logo and RHCE are trademarks of Red Hat Inc registered in the United States and other countries Linux is the registered trademark of Linus Torvalds in the United States and other countries Java is a registered trademark of Oracle and or its affiliates XFS is a trademark of Silicon Graphics International Corp or its subsidiaries in the United States and or other countries MySQL is a registered trademark of MySQL AB in the United States the European Union and other countries All other trademarks are the property of the
40. WARF debug information compressed with dwz has been added Control over the IR optimizer s handling of the tradeoff between performance and precision of exceptions has been improved In particular the vex iropt precise memory exns command line option has been replaced by vex iropt register updates which provides extended functionality and allows the Valgrind gdbserver to always show up to date register values to GDB Modest performance gains have been achieved by the use of translation chaining for JIT generated code The memory consumption of the Memcheck tool has been reduced in some scenarios Handling of freed memory in the Memcheck tool has been improved which allows the tool to detect use after free that would previously have been missed The performance of the Helgrind tool has been improved As well the tool now consumes less memory especially when working with large long running applications that perform many synchronization events such as lock unlock and similar Helgrind now displays locksets for both threads involved in a race Helgrind now displays error messages that are better formatted and generally easier to understand Helgrind now provides facilities and documentation regarding annotation of thread safe reference counted C classes A new command line option check stack refs no yes has been added to Helgrind This option allows you to disable race checking on thread stacks The option is set to yes by default A
41. ages See Also in C C and Fortran on the command line 58 Part V Getting Help Part V Getting Help Red Hat Developer Toolset 1 x User Guide 59 Chapter 11 Accessing Red Hat Product Documentation central source of information It is currently translated in 22 languages and for each product it provides different kinds of books from release and technical notes to installation user and reference guides in HTML PDF and EPUB formats Below is a brief list of documents that are directly or indirectly relevant to this book Red Hat Developer Toolset Red Hat Developer Toolset 1 1 explains the concept of Software Collections and documents the scl tool Red Hat Enterprise Linux provides detailed information about libraries and runtime support compiling and building debugging and profiling Linux 6 documents relevant information regarding the deployment configuration and administration of Red Hat Enterprise Linux 6 Linux 5 documents relevant information regarding the deployment configuration and administration of Red Hat Enterprise Linux 5 60 Chapter 12 Accessing the Customer Portal Chapter 12 Accessing the Customer Portal The Customer Portal is available to all Red Hat subscribers and can be accessed at of most interest to developers are the Plan Deploy and Connect menus These include links to all the resources needed during each stage of the development 12 1 The Plan Menu Webinars Success
42. al and complex arguments and AT AN Y X now serves as an alias for AT AN2 Y X The BLOCK construct has been implemented B 1 2 6 Fortran 2008 Compatibility The implementation of the ASYNCHRONOUS attribute in GCC is now compatible with the candidate draft of TS 29113 Technical Specification on Further Interoperability with C B 1 2 7 Fortran 77 Compatibility When the GNU Fortran compiler is issued with the fno sign zero option the SIGN intrinsic now behaves as if zero were always positive B 1 3 Architecture specific Options Vectors of type vector long long or vector long are passed and returned using the same method as other vectors with the VSX instruction set Previously GCC did not adhere to the ABI for 128 bit vectors with 64 bit integer base types see GCC PR 48857 The mrecip command line option has been added which indicates whether the reciprocal and reciprocal square root instructions should be used The mveclibabi mass command line option has been added This can be used to enable the compiler to auto vectorize mathematical functions using the Mathematical Acceleration Subsystem library Red Hat Developer Toolset 1 x User Guide 93 The msingle pic base command line option has been added which instructs the compiler to avoid loading the PIC base register in function prologues The PIC base register must be initialized by the runtime system The mblock move inline limit command line option has been added
43. am accepts any command line arguments you can provide them as arguments to the run command run argument The execution stops when a first breakpoint if any is reached when an error occurs or when the program terminates Example 3 8 Executing the fibonacci Binary File execute the fibonacci binary file by running the following command gdb run Starting program home john fibonacci Breakpoint 1 main argc 1 argv 0x7fffffffe4d8 at fibonacci c 10 10 printf ld b 3 7 Displaying Current Values The gdb utility allows you to display the value of almost anything that is relevant to the program from a variable of any complexity to a valid expression or even a library function However the most common task is to display the value of a variable To display the current value of a certain variable run the following command 34 Chapter 3 GNU Debugger GDB print variable name Example 3 9 Displaying the Current Values of Variables and the execution of the fibonacci binary stopped after reaching the breakpoint at line 10 you can display the current values of variables a and b as follows gdb print a 1 0 gdb print b 2 1 3 8 Continuing Execution To resume the execution of the program you are debugging after it reached a breakpoint run the following command continue The execution stops again when another breakpoint is reached To skip a certain number of breakpoints typically when you are
44. arlier versions of GCC ignored all options starting with For example options accepted by the linker such as as needed and export dynamic are not accepted by gcc and g anymore and should now be directed to the linker using W1 as needed or W1 export dynamic if that is intended for the older intermodule optimization framework has been removed and the combine command line option is not accepted anymore A 2 Changes in GDB 7 4 Red Hat Developer Toolset 1 0 is distributed with GDB 7 4 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version Below is a comprehensive list of new features and compatibility changes in this release For details on how to use these new features refer to the GDB documentation A 2 1 New Features Changes Since Red Hat Enterprise Linux 6 2 The following features have been added since the release of the GNU Debugger included in Red Hat Enterprise Linux 6 2 Support for linespecs has been improved in particular a more consistent handling of ambiguous linespecs some support for labels in the program s source and FILE LINE support now extends to further linespecs types Breakpoints are now set on all matching locations in all inferiors and will be updated according to changes in the inferior New inferior control commands skip function and skip file have been added These commands can be uses to skip certain functions and files when stepping
45. attribute pointer attribute and with a non constant length type parameter are now supported Support has been added for procedure pointer function results and procedure pointer components including PASS Support has been added for allocatable scalars experimental DEFERRED type bound procedures and the ERRMSG argument of the ALLOCATE and DEALLOCATE statements The ALLOCATE statement now supports type specs and the SOURCE argument Rounding ROUND RZ for output is now supported The INT FAST 8 16 32 64 128 T format for ISO C BINDING intrinsic module type parameters is now supported OPERATOR and ASSIGNMENT are now allowed as GENERIC type bound procedures i e as type bound operators B 1 2 4 Fortran 2003 Compatibility Extensible derived types with type bound procedure or procedure pointer with PASS attribute now have to use CLASS in line with the Fortran 2003 standard the workaround to use T YPE is no longer supported B 1 2 5 Fortran 2008 Features A new command line option std f2008ts has been added This option enables support for programs that conform to the Fortran 2008 standard and the draft Technical Specification T S The DO CONCURRENT construct is now supported This construct can be used to specify that individual loop iterations do not have any interdependencies Full single image support except for polymorphic coarrays has been added and can be enabled by using the fcoarray single command li
46. b a e b b sum rL_____7_ __ _ _______ _ mn Problems javadoc Declaration Console 23 xk xi Ee et terminated Fibonacci Java Application usr lib jvm java 1 6 0 openjdk 1 6 0 0 x86 64 bin java Feb 29 2012 1 11235 8 13 21 34 55 89 144 233 377 618 987 1597 2584 4181 6765 16946 17711 28657 46368 M X Smart Insert 8 39 Figure 10 1 Sample Eclipse Session 10 1 Installing Eclipse In Red Hat Enterprise Linux 6 the Eclipse development environment is distributed as a set of several smaller packages such as eclipse cdt which provides C C support eclipse jdt which provides support for Java or eclipse valgrind which integrates various Valgrind tools into Eclipse In addition a package group named Eclipse is available to make it easier to install all packages that form the Eclipse integrated development environment at the same time To install the Eclipse package group and all its dependencies on your system type the following at a shell prompt as root yum groupinstall Eclipse 56 Chapter 10 Eclipse This installs eclipse cat eclipse jdt eclipse valgrind and other packages to the system from the Red Hat Enterprise Linux 6 x86 x86 64 Supplementary channel To install all Eclipse packages run as root yum install eclipse raumm m Eclipse is part of Red Hat Enterprise Linux rather than Red Hat Developer Toolset It is only available for Red Hat Enterprise Linux 6 on
47. be provided or the default constructor needs to be added Visibility of Template Instantiations The ELF symbol visibility of a template instantiation is now properly constrained by the visibility of its template arguments For instance users that instantiate standard library components like std vector with hidden user defined types such as struct my hidden struct can now expect hidden visibility for std vector my hidden struct symbols As a result users that compile with the fvisibility hidden command line option should be aware of the visibility of types included from the library headers used If the header does not explicitly control symbol visibility types from those headers will be hidden along with instantiations that use those types For instance consider the following code include lt vector gt template std vector has default visibility include lt ctime gt struct tm has hidden visibility template class std vector lt tm gt instantiation has hidden visibility One approach to adjusting the visibility of a library header lt foo h gt is to create a forwarding header on the I include path consisting of the following pragma GCC visibility push default include_next lt foo h gt pragma GCC visibility push User defined Literal Support When compiling C with the std c 11 c 0x gnu 11 gnu 0x command line option GCC 4 7 0 unlike older versions supports user defined literals which are incompatibl
48. c library Consequently this feature is currently available in Red Hat Developer Toolset for Red Hat Enterprise Linux 6 The as needed command line option has been adapted to link in a dynamic library in the following two cases 1 if the dynamic library satisfies undefined symbols in regular objects and 2 if the dynamic library satisfies undefined symbols in other dynamic libraries unless the library is already found in a DT NEEDED entry of one of the libraries that are already linked The 1 file name command line option now searches the library path for a file name called file name without adding the a or so file extension 86 Changes in Version 1 0 A 3 2 GNU Assembler A 3 2 1 New Features Changes Since Red Hat Enterprise Linux 6 2 The following features have been added since the release of the binutils included in Red Hat Enterprise Linux 6 2 The GNU Assembler no longer requires double ampersands in macros A new compress debug sections command line option has been added to enable compression of DWARF debug information sections in the relocatable output file Compressed debug sections are currently supported by the readelf objdump and gold tools but not by 1d Changes Since Red Hat Enterprise Linux 5 8 In addition to the above changes the following features have been added since the release of the binutils included in Red Hat Enterprise Linux 5 8 GNU Linux targets now support gnu unique object as a value of the t
49. command New commands may write registers set may write memory set may insert breakpoints set may insert tracepoints set may insert fast tracepoints and 00 Channe i Vlarcinn 10 Changes in Version 1 0 set may interrupt have been added All of these commands accept either on or off as an argument and can be used to set individual permissions for the target A new command main info program spaces has been added This command can be used to display information about currently loaded program spaces New commands set remote interrupt sequence and show remote interrupt sequence have been added The set remote interrupt sequence command accepts Ctr1 C BREAK and BREAK g as valid arguments and can be used to specify which interrupt sequence to send to the remote target in order to interrupt its execution Use the show remote interrupt sequence to determine the current setting New commands set remote interrupt on connect and show remote interrupt on connect have been added The set remote interrupt on connect accepts either on or off as an argument and can be used to enable sending an interrupt sequence to the remote target when the GNU Debugger connects to it Use the show remote interrupt on connect command to determine whether this feature is enabled The set remotebreak and show remotebreak commands have been deprecated and users are advised to use set remote interrupt sequence and show remote interrupt sequence instead The disassemb
50. ct file from an assembly language program run the as tool as follows scl enable devtoolset 1 1 as option o object file source file This creates an object file named object file in the current working directory Red Hat Developer Toolset 1 x User Guide 37 Note that you can execute any command using the sc l utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset as as default scl enable devtoolset 1 1 bash K CO To verify the version of as you are using at any point type the following at a shell prompt which as Red Hat Developer Toolset s as executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset as as v 4 3 Using the GNU Linker To create an executable binary file or a library from object files run the 1d tool as follows scl enable devtoolset 1 1 ld option o output file object file This creates a binary file named output file in the current working directory If the o option is omitted the compiler creates a file named a out by default Note that you can execute any command using the sc l utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivale
51. d Hat Developer Toolset s version of GCC The following text attempts to identify major issues and suggests solutions A 1 2 1 C Constant expressions are now handled by GCC in a way that conforms to C90 and C99 For code expressions that can be transformed into constants by the compiler but are in fact not constant expressions as defined by ISO C this may cause warnings or errors Ill formed redeclarations of library functions are not accepted anymore by the compiler In particular a function with a signature similar to the built in declaration of a library function for example abort or memcpy must be declared with extern C to be considered as a redeclaration otherwise it is ill formed Duplicate Member Consider the following struct declaration SETS A Tm bea SUDO SE Serie lt P alinic ele je go ke Previously this declaration used to be diagnosed just by the C compiler now it is diagnosed also by the C compiler Because of the anonymous unions and structs there is ambiguity about what a actually refers to and one of the fields therefore needs to be renamed A 1 2 2 C Header Dependency Changes lt iostream gt lt string gt and other STL headers that previously included lt unistd h gt as an implementation detail to get some feature macros for gthr h purposes no longer do so because it was a C standard violation This can result in diagnostic output similar to the following Red Hat Developer Toolset
52. d has been renamed to info auto load python scripts pattern and is no longer classified as a maintenance only command Support for the Guile extension language has been removed The GNU Debugger has been adapted to follow GCC s rules on accessing volatile objects when reading or writing target state during expression evaluation Changes Since Red Hat Enterprise Linux 5 8 No noteworthy changes that affect compatibility have been made in addition to those described above A 3 Changes in binutils 2 22 52 Red Hat Developer Toolset 1 0 is distributed with binutils 2 22 52 which provides a number of bug 84 Changes in Version 1 0 fixes and feature enhancements over the Red Hat Enterprise Linux system version Below is a comprehensive list of new features and compatibility changes in this release For details on how to use The GNU assembler as GNU linker 1d newly added ELF linker gold and other binary tools that are part of the binutils are now released under the GNU General Public License version 3 A 3 1 GNU Linker Another ELF linker gold is now available in addition to 1d the existing GNU linker gold is intended to be a drop in replacement for 1d so 1d s documentation is intended to be the reference documentation gold supports most of 1d s features except notable ones such as MRI compatible linker scripts cross reference reports cref and various other minor options It also provides significantly improved link
53. d line option smc check all non file has been added to add the relevant consistency checks only to code that originates in non file backed mappings In effect this confines the consistency checking only to code that is or might be JIT generated and avoids checks on code that must have been compiled ahead of time Consequently this functionality significantly improves the performance of applications that generate code at run time New client requests VALGRIND DISABLE ERROR REPORTING and VALGRIND ENABLE ERROR REPORT ING have been added These requests enable and disable error reporting on a per thread and nestable basis which is useful for hiding errors in particularly troublesome pieces of code The MPI wrapper library libmpiwrap c now uses this facility The mod funcname command line option has been added to cg diff Changes Since Red Hat Enterprise Linux 5 9 In addition to the above changes the following features have been added since the release of Valgrind included in Red Hat Enterprise Linux 5 9 When running in 64 bit mode Valgrind now supports the SSEA 2 instruction set with the exception of SSEA 2 AES instructions In 32 bit mode Valgrind only provides support up to and including the SSSE3 instruction set A new processing script cg diff has been added to Cachegrind This processing script can find the difference between two profiles and can therefore be used to evaluate the performance effects of a change in a program
54. ded to DRD The free is write option allows you to detect reading from already freed memory the trace alloc can be used to trace of all memory allocations and deallocations A number of new allocations have been added to DRD As well you can now annotate custom barrier implementations and benign races on static variables DRD s happens before and happens after annotations have been enhanced and can be used to annotate for example a smart pointer implementation Helgrind s annotation set has been significantly improved to provide a general set of annotations to describe locks semaphores barriers and condition variables In addition Helgrind now supports annotations to describe thread safe reference counted heap objects A new command line option show possibly lost has been added to Memcheck By default this option is enabled and causes the leak detector to show possibly lost blocks A new experimental heap profiler DHAT Dynamic Heap Analysis Tool has been added DHAT keeps track of allocated heap blocks and also inspects every memory reference to see which block 100 Changes in Version 1 1 if any is being accessed This gives a lot of insight into block lifetimes utilization turnover liveness and the location of hot and cold fields You can use DHAT to do hot field profiling Support for unfriendly self modifying code has been improved and the extra overhead incurred by smc check all1 has been reduced by approximate
55. define a fast tracepoint at that location Support for disconnected tracing trace files and circular trace buffer has been added A new teval command has been added This command accepts one or more expressions to evaluate at a tracepoint The GNU Debugger has been adapted to parse the Ob prefix of binary numbers exactly the same way as the GNU Compiler Collection The GNU Debugger now supports the following commands for process record and replay New commands set record memory and show record memory have been added The set record memory command accepts on or of f as an argument and can be used to enable or disable stopping the inferior when a memory change of the next instruction cannot be recorded Use the show record memory query command to determine whether this feature is enabled A new command record save has been added This command accepts a file name as an argument and can be used to save the execution log to a file A new command record restore has been added This command accepts a file name as an argument and can be used to restore the execution log from a file A new command eval has been added This command accepts a format string followed by one or more arguments transforms it to a command and then executes it A new command save breakpoints has been added This command accepts a file name as an argument and can be used to store all currently defined breakpoints to a file To restore the saved breakpoints from this file use the source
56. dvisory is supplied to give the details of the issues being fixed as well as how to obtain and install the required software packages This section has information about the errata including Checking the security update policy and lifetime for all Red Hat products 62 Chapter 12 Accessing the Customer Portal Getting the latest security updates for Red Hat products Getting notified of new security updates Finding out if a specific CVE affects a Red Hat product Reporting a security vulnerability How we measure security vulnerabilities Security Response Team mission and standards of service Support This is where all the information regarding Red Hat support can be found including links for Support Cases Support Programs Product Life Cycles Supported Environments Help amp Assistance Site Help 12 3 The Connect Menu Knowledgebase Groups PLAN CONNECT Videos Tech Briefs k Source Support Cases Figure 12 3 The Connect Menu The Connect menu allows you to connect to the industry s best engineers and collaborate with industry peers This includes Knowledgebase The Knowledgebase contains a large number of whitepapers on a variety of topics which can serve as another source of documentation for your project Note that the Knowledgebase section requires you to enter your Red Hat login and password Groups This section allows users to join a group to collaborate on the documents They can als
57. e Replace channel name with the name you determined in the previous step 3 To verify the list of channels you are subscribed to at any time run as root rhn channel list Classic refer to the Red Hat Subscription Management Guide 1 4 2 Using Red Hat Subscription Management If your system is registered with Red Hat Subscription Management complete the following steps to attach a subscription that provides access to the repository for Red Hat Developer Toolset and then enable that repository 1 Display a list of all subscriptions that are available for your system to determine the pool ID of a subscription that provides Red Hat Developer Toolset To do so type the following at a shell prompt as root 16 Chapter 1 Red Hat Developer Toolset subscription manager list available For each available subscription this command displays its name unique identifier expiration date and other details related to your subscription The pool ID is listed on a line beginning with Pool Id For a complete list of subscriptions that provide access to Red Hat Developer Toolset refer to 2 Attach the appropriate subscription to your system by running the following command as root subscription manager subscribe pool pool id Replace pool id with the pool ID you determined in the previous step To verify the list of subscriptions your system has currently attached at any time run as root subscription manager list consumed 3
58. e and why 50 Chapter 8 Valgrind Red Hat Developer Toolset 1 x User Guide 51 Chapter 9 OProfile OProfile is a low overhead system wide profiler that uses the performance monitoring hardware on the processor to retrieve information about the kernel and executables on the system such as when memory is referenced the number of level 2 cache L2 requests and the number of hardware interrupts received It consists of a configuration utility a daemon for collecting data and a number of tools that can be used to transform the data into a human readable form For a complete list of tools that are OProfile profiles an application without adding any instrumentation by recording the details of every nth event This allows it to consume fewer resources than Valgrind but also causes its samples to be less precise Unlike Valgrind which only collects data for a single process and its children in user space OProfile is well suited to collect system wide data on both user space and kernel space processes and requires root privileges to run Red Hat Developer Toolset is distributed with OProfile 0 9 7 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements Table 9 1 Tools Distributed with OProfile for Red Hat Developer Toolset Name Description oprofiled The OProfile daemon that collects profiling data opcontrol Starts stops and configures the OProfile daemon o
59. e been added A new gdb parameter directories function call is now available A new function gdb newest frame has been added This function can be used to return the newest frame in the selected thread The gdb InferiorThread class now supports a new name attribute Support for inferior events has been added Python scripts can now add observers in order to be notified of events occurring in the process being debugged Changes Since Red Hat Enterprise Linux 5 8 In addition to the above changes the following features have been added since the release of GNU Debugger included in Red Hat Enterprise Linux 5 8 For remote targets debugging of shared libraries is now supported by default New commands set observer and show observer have been added The set observer command accepts on or off as an argument and can be used to allow or disallow the GNU Debugger to affect the execution of the debugged program Use the show observer command to determine whether observer mode is enabled A new convenience variable _thread has been added This variable stores the number of the Red Hat Developer Toolset 1 x User Guide 81 current thread The source command now accepts s as a valid option This option can be used to search for the script in the source search path regardless of the path in the file name Support for tracepoints including fast and static tracepoints has been added to gdbserver The batch command line option has been adap
60. e following features have been added since the release of binutils included in Red Hat Enterprise Linux 6 3 and 5 9 Support for bundle align mode bundle lock and bundle unlock directives for x86 96 Changes in Version 1 1 targets has been added On x86 architectures the GNU Assembler now allows rep bsf rep bsr andrep ret syntax B 3 3 Other Binary Tools The following features have been added since the release of binutils included in Red Hat Enterprise Linux 6 3 and 5 9 Support for dwz m optimized debug information has been added The devtoolset 1 1 binutils devel package now provides the demangle h header file B 4 Changes in elfutils 0 154 Red Hat Developer Toolset 1 1 is distributed with elfutils 0 154 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version Below is a comprehensive list of new features in this release Changes Since Red Hat Enterprise Linux 6 3 The following features have been added since the release of elfutils included in Red Hat Enterprise Linux 6 3 libdw now handles compressed debuginfo sections The dwarf highpc function now handles the DWARF 4 DW AT high pc constant form eu nm now supports C demangling eu ar now supports a new modifier D for deterministic output with no UID GID or mtime info The U modifier is the inverse eu readelf can now print SDT ELF notes SystemTap probes and the gdb index GDB section It can also now p
61. e with some valid ISO C 03 code In particular white space is now needed after a string literal before something that could be a valid user defined literal Consider the following code const char p foobar TIME Red Hat Developer Toolset 1 x User Guide 75 In C 03 the TIME macro expands to some string literal and is concatenated with the other one In C 11 TIME is not expanded and instead operator TIME is being looked up which results in a warning like error unable to find string literal operator operator _ TIME This applies to any string literal followed without white space by some macro T o fix this add some white space between the string literal and the macro name Taking the Address of Temporary Consider the following code struct S S 0 int ale de void bar S void foo bar es Previously an attempt to compile this code produced a warning message now it fails with an error This can be fixed by adding a variable and passing the address of this variable instead of the temporary The fpermissive compiler flag turns compile time errors into warnings and can be used as a temporary workaround Miscellaneous G now sets the predefined macro _ cplusplus to the correct value 199711L for C 98 03 and 201103L for C 11 G now properly re uses stack space allocated for temporary objects when their lifetime ends which can significantly lower stack consumption for some C function
62. ed New commands set auto load and show auto 1oad have been added and can be used to control automatic loading of files The set auto load gdb scripts and show auto load gdb scripts commands control automatic loading of GDB scripts The set auto load python scripts and show auto load python scripts commands control automatic loading of Python scripts The set auto load local gdbinit and show auto load local gdbinit commands control automatic loading of gdbinit from the current working directory The set auto load libthread db and show auto load libthread db commands control automatic loading of inferior specific 13bthread db The set auto load scripts directory and show auto load scripts directory commands control the list of directories from which to automatically load GDB and Python scripts The set auto load safe path and show auto load safe path commands control the list of directories from which it is safe to automatically load all previously mentioned items The set debug auto load and show debug auto load commands control displaying of debugging information for all previously mentioned items The set auto load off command can be used to disable automatic loading globally You can also use show auto load with no subcommand to display current settings of all previously mentioned items The maint set python auto load on off command has been replaced with set auto load python scripts onJoff The maintenance print section scripts comman
63. efore function and source file names A new command line option pretty print or p for short has been added to the addr2line tool This option can be used to produce human readable output Changes Since Red Hat Enterprise Linux 5 8 In addition to the above changes the following features have been added since the release of the binutils included in Red Hat Enterprise Linux 5 8 A new command line option insn width width has been added to the obj dump tool This option can be used to specify the number of bytes to be displayed on a single line when disassembling instructions A new command line option relocated dumpzname number has been added to the readelf tool This option can be used to display the relocated contents of a section as a sequence of bytes A new command line option external symbols table filename has been added to the gprof tool This option can be used to read a symbol table from a certain file bfd now supports a plugin target which can be used to get basic support for new file formats by having the plugin target load the same shared objects used by gold The dwarf or W for short command line option of the obj dump tool has been adapted to be as flexible as the debug dump or w option of readelf New command line options prefix prefixand prefix strip level have been added to the objdump tool These options can be used to add absolute paths for the source or S for short option A new command
64. egin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset ob j dump objdump v 4 5 Additional Resources A detailed description of binutils is beyond the scope of this book For more information refer to the resources listed below Installed Documentation as 1 Id 1 addr2line 1 ar 1 c filt 1 elfedit 1 gprof 1 nm 1 objcopy 1 objdump 1 ranlib 1 readelf 1 size 1 strings 1 strip 1 Manual pages for various binutils tools provide more information about their respective usage To display a manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 1 1 man tool Online Documentation binary tools and their usage See Also improvements over the Red Hat Enterprise Linux system version of binutils Red Hat Developer Toolset 1 x User Guide 39 in C C and Fortran H FEA 40 Chapter 5 elfutils Chapter 5 elfutils elfutils is a collection of various binary tools such as eu obj dump eu readelf and other utilities Toolset version of elfutils Red Hat Developer Toolset is distributed with elfutils 0 154 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements Table 5 1 Tools Included in elfutils for Red Hat Developer Toolset Name Description eu addr2line Translates addresses into file nam
65. ell prompt which opcontrol Red Hat Developer Toolset s opcontrol executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset OProfile opcontrol version 9 3 Additional Resources A detailed description of OProfile and its features is beyond the scope of this book For more information refer to the resources listed below Installed Documentation oprofile 1 The manual page named oprofile provides an overview of OProfile and available tools To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 1 1 man oprofile opannotate 1 oparchive 1 opcontrol 1 opgprof 1 ophelp 1 opimport 1 opreport 1 Manual pages for various tools distributed with OProfile provide more information on their respective usage To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 1 1 man tool Online Documentation Linux 5 describes in detail how to install configure and start using OProfile on this system See Also information on how to install it on your system Red Hat Developer Toolset 1 x User Guide 53 and memory management problems such as the use of uninitialized memory improper allocation and freeing of memory and the use of improper arguments in system calls 54 Part IV Integrated Development Enviro
66. en added The set basenames may differ command enables support for source files with multiple base names The show basenames may differ command can be used to determine whether this support is enabled The default option is off to allow faster GDB operations A new command line option ix or init command has been added This option acts like x or command but is executed before loading the debugged program A new command line option iex or init eval command has been added This option acts like ex or eval command but is executed before loading the debugged program The following changes have been made to the C language support since the release of the GNU Debugger included in Red Hat Enterprise Linux 6 2 When debugging a template instantiation parameters of the template are now put in scope The following changes have been made to the Python scripting support since the release of the GNU Debugger included in Red Hat Enterprise Linux 6 2 Theregister pretty printer function in module gdb printing now takes an optional 80 Changes in Version 1 0 replace argument The maint set python print stack on off command has been deprecated and will be deleted in GDB 7 5 The new command set python print stack none full message has replaced it A prompt substitution hook prompt hook is now available to the Python API A new Python module gdb prompt has been added to the GDB Python modules library Python commands and co
67. er option performs pointer association checks in calls but does not handle undefined pointers nor pointers in expressions 90 Changes in Version 1 1 The fcheck all option enables all of the above options A new command line option fno protect parens has been added This option allows the compiler to reorder REAL and COMPLEX expressions with no regard to parentheses When OpenMP s WORKSHARE is used array assignments and WHERE will now be run in parallel More Fortran 2003 and Fortran 2008 mathematical functions can now be used as initialization expressions The GCC compiler directive now enables support for some extended attributes such as STDCALL B 1 2 2 Compatibility Changes The Ofast command line option now automatically enables the fno protect parens and fstack arrays flags Front end optimizations can now be disabled by the fno frontend optimize option and selected by the ffrontend optimize option The former is essentially only desirable if invalid Fortran source code needs to be compiled for example when functions as compared to subroutines have side effects or to work around compiler bugs The GFORTRAN USE STDERR environment variable has been removed and GNU Fortran now always prints error messages to standard error The fdump core command line option and the GFORTRAN ERROR DUMPCORE environment variable have been removed When encountering a serious error GNU Fortran now always aborts the execution of t
68. erprise Linux 5 See Also over the Red Hat Enterprise Linux system versions of the GNU Compiler Collection GNU Debugger and binutils as well as information about the language ABl and debugging compatibility Red Hat Developer Toolset 1 x User Guide 19 Part Il Development Tools 20 Chapter 2 GNU Compiler Collection GCC Chapter 2 GNU Compiler Collection GCC The GNU Compiler Collection commonly abbreviated GCC is a portable compiler suite with support for a wide selection of programming languages Red Hat Developer Toolset is distributed with GCC 4 7 2 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements including optimization for various new Intel and AMD processors support for OpenMP 3 1 and link time optimization This version also includes experimental support for the C 11 standard C 11 atomic 2 1 GNU C Compiler 2 1 1 Installing the C Compiler In Red Hat Developer Toolset the GNU C compiler is provided by the devtoolset 1 1 gcc package and is 2 1 2 Using the C Compiler To compile a C program on the command line run the gcc compiler as follows scl enable devtoolset 1 1 gcc o output file source file This creates a binary file named output file in the current working directory If the o option is omitted the compiler creates a file named a out by default When you are working on a project that consists of several s
69. es and line numbers eu ar Creates modifies and extracts files from archives eu elfcmp Compares relevant parts of two ELF files for equality eu elflint Verifies that ELF files are compliant with the generic ABI gABI and processor specific supplement ABI psABI specification eu findtextrel Locates the source of text relocations in files eu make debug Creates an offline archive for debugging archive eu nm Lists symbols from object files eu objdump Displays information from object files eu ranlib Generates an index to the contents of an archive to make access to this archive faster eu readelf Displays information about ELF files eu size Lists section sizes of object or archive files eu strings Displays printable character sequences in files eu strip Discards all symbols from object files eu unstrip Combines stripped files with separate symbols and debug information 5 1 Installing elfutils In Red Hat Developer Toolset elfutils is provided by the devtoolset 1 1 elfutils package and is 5 2 Using elfutils To execute any of the tools that are part of elfutils run the command as follows scl enable devtoolset 1 1 tool option file_name distributed with elfutils For example to use the eu obj dump tool to inspect an object file type scl enable devtoolset 1 1 eu objdump option object file Note that you can execute any command using the sc l utility causing it to be run with the Red Hat Red
70. es numerous bug fixes and enhancements including improved support for Python scripting ambiguous line specifications and tracepoints as well as improved inferior control commands and handling of C debugee executables For a detailed list of 3 1 Installing the GNU Debugger In Red Hat Developer Toolset the GNU Debugger is provided by the devtoolset 1 1 gdb package and is 3 2 Preparing a Program for Debugging Compiling Programs with Debugging Information To compile a C program with debugging information that can be read by the GNU Debugger make sure the gcc compiler is run with the g option To do so on the command line use a command in the following form scl enable devtoolset 1 1 gcc g o output file input file Similarly to compile a C program with debugging information run scl enable devtoolset 1 1 g g o output file input file Red Hat Developer Toolset 1 x User Guide 29 Example 3 1 Compiling a C Program With Debugging Information Imagine you have a source file named fibonacci c with the following contents include lt stdio h gt include lt limits h gt int main int argc char argv unsigned long int a 0 unsigned long int b 1 unsigned long int sum while b lt LONG_MAX printf ld b sum a b a b b sum return 0 To compile this program on the command line using GCC from Red Hat Developer Toolset with debugging information for the GNU Debugger
71. f memory and the use of improper arguments in system calls greatest amount of CPU time and why 48 Chapter 8 Valgrind Chapter 8 Valgrind Valgrind is an instrumentation framework that ships with a number of tools to profile applications It can be used to detect various memory errors and memory management problems such as the use of uninitialized memory or improper allocation and freeing of memory or to identify the use of improper arguments in system calls For a complete list of profiling tools that are distributed with the Red Hat Valgrind profiles an application by rewriting it and instrumenting the rewritten binary This allows you to profile your application without the need to recompile it but it also makes Valgrind significantly slower than other profilers especially when performing extremely detailed runs It is therefore not suited to debugging time specific issues or kernel space debugging Red Hat Developer Toolset is distributed with Valgrind 3 8 1 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements Table 8 1 Tools Distributed with Valgrind for Red Hat Developer Toolset Name Description Memcheck Detects memory management problems by intercepting system calls and checking all read and write operations Cachegrind Identifies the sources of cache misses by simulating the level 1 instruction cache 11 level 1 data cache D1 and unified
72. ging information in a binary file run the dwz tool as follows scl enable devtoolset 1 1 dwz option file name Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset dwz as default scl enable devtoolset 1 1 bash rrauummmm To verify the version of dwz you are using at any point type the following at a shell prompt which dwz Red Hat Developer Toolset s dwz executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset dwz dwz v 6 3 Additional Resources A detailed description of dwz and its features is beyond the scope of this book For more information refer to the resources listed below Installed Documentation dwz 1 The manual page for the dwz utility provides detailed information on its usage To display the manual page for the version included in Red Hat Developer Toolset type Red Hat Developer Toolset 1 x User Guide 43 scl enable devtoolset 1 1 man dwz See Also ELF files 44 Part Ill Performance Monitoring Tools Part Ill Performance Monitoring Tools B Red Hat Developer Toolset 1 x User Guide 45 Chapter 7 SystemT ap SystemTap is a tracing and probing to
73. h as T CMalloc or JEMalloc This option is however very general and does not necessarily apply only to malloc family functions A new command line option redzone size number has been added to tools that provide their own replacement for malloc and other functions This option allows you to specify the size of the padding blocks also known as redzones that are added before and after each client allocated block Smaller values reduce the amount of memory required by Valgrind bigger numbers increase the chance to detect blocks that are overrun or underrun The leak check GDB server monitor command now can now be used to control the maximum number of loss records that Memcheck outputs Memcheck now uses less memory when working with applications that allocate a large number of blocks or that have many partially defined bytes A new GDB server monitor command block list has been added This allows Memcheck to list the addresses and sizes of the blocks of a leak search loss record A new GDB server monitor command who points at has been added This allows Memcheck to list the locations that are pointing at a block When the Memcheck tool is executed with a redzone size greater than O VALGRIND MALLOCLIKE BLOCK detects an invalid access of these redzones by marking them noaccess Similarly if a redzone size is given for a memory pool VALGRIND MEMPOOL ALLOC marks the redzones noaccess Note that this functionality still allows you to find some bugs
74. h btver1 and mtune btver1 Optimization for AMD family 14 processors code named Bobcat march bdver1 and mtune bdver1 Optimization for AMD family 15 processors code named Bulldozer Support for various processor specific intrinsics and instructions is now available through the command Red Hat Developer Toolset 1 x User Guide 71 Table A 2 Support for Processor specific Intrinsics and Instructions Option Description mavx2 Support for Intel AVX2 intrinsics built in functions and code generation mbmi2 Support for Intel BMI2 intrinsics built in functions and code generation mlzcnt Implementation and automatic generation of builtin clz using the lzcnt instruction nfma Support for Intel FMA3 intrinsics and code generation nfsgsbase Enables the generation of new segment register read write instructions through dedicated built ins mrdrnd Support for the Intel rdrnd instruction nfi6c Support for two additional AVX vector conversion instructions mtbm Support for T BM Trailing Bit Manipulation built in functions and code generation mbmi Support for AMD s BMI Bit Manipulation built in functions and code generation mcrc32 Support for crc32 intrinsics mmovbe Enables the use of the movbe instruction to implement builtin bswap32 and builtin bswap64 mxop mfma4 and Support for the XOP FMA4 and LWP instruction sets for the AMD Orochi mlwp processors mabm Enables the use of the popcnt and 1zc
75. he C 11 memory model programs that use transactions must be free of data races Transactions are guaranteed to be virtually executed serially in a global total order that is determined by the transactional memory implementation and that is consistent with and contributes to the happens before order enforced by the rest of the program that is transaction semantics are specified based on the C 11 memory model see the draft specification linked above Nonetheless if a program is not data race free then it has undefined behavior For example a thread can first initialize some data and then make it publicly accessible by code like this init data transaction atomic data public true data public is initially false Another thread can then safely use the data for instance transaction atomic f if data public use data However the following code has a data race and thus results in undefined behavior transaction atomic temp copy data if data public use temp Here copy data races with init data in the initializing thread because this can be executed even if data public is not true Another example for data races is one thread accessing a variable x transactionally and another thread accessing it nontransactionally at potentially the same time Note that the data can be safely reclaimed using code like this assuming only one thread ever does this transaction atomic f data public false destruct data
76. he current working directory 2 2 3 Running a C Program When g compiles a program it creates an executable binary file To run this program on the command line change to the directory with the executable file and type file name 24 Chapter 2 GNU Compiler Collection GCC Example 2 4 Running a C Program on the Command Line prompt hello Hello World 2 3 GNU Fortran Compiler 2 3 1 Installing the Fortran Compiler In Red Hat Developer Toolset the GNU Fortran compiler is provided by the devtoolset 1 1 gcc gfortran 2 3 2 Using the Fortran Compiler To compile a Fortran program on the command line run the gfortran compiler as follows scl enable devtoolset 1 1 gfortran o output file source file This creates a binary file named output file in the current working directory If the o option is omitted the compiler creates a file named a out by default When you are working on a project that consists of several source files it is common to compile an object file for each of the source files first and then link these object files together This way when you change a single source file you can recompile only this file without having to compile the entire project To compile an object file on the command line run the following command scl enable devtoolset 1 1 gfortran o object file c source file This creates an object file named object file If the o option is omitted the com
77. he program The fbacktrace command line option is now enabled by default When a fatal error occurs GNU Fortran now attempts to print a backtrace to standard error before aborting the execution of the program To disable this behavior use the fno backtrace option GNU Fortran no longer supports the use of the M command line option to generate Makefile dependencies for the module path To perform this operation use the J option instead To significantly reduce the number of warnings the Wconversion command line option now only displays warnings when a conversion leads to information loss and a new command line option Wconversion extra has been added to display warnings about other conversions The Wconver sion option is now enabled with Wall A new command line option Wunused dummy argument has been added This option can be used to display warnings about unused dummy arguments and is now enabled with Wa ll Note that the Wunused variable option previously also warned about unused dummy arguments The COMMON default padding has been changed Previously the padding was added before a variable Now it is added after a variable to increase the compatibility with other vendors as well as to help to obtain the correct output in some cases Note that this behavior is in contrast with the behavior of the falign commons option GNU Fortran no longer links against the 1ibgfortranbegin library The MAIN assembler symbol is the actual
78. ic transactions This has implications for when transactions call functions that are defined within other compilation unit source file or within libraries To enable such cross compilation unit calls for transactional code the respective functions must be marked to contain code that is safe to use from within atomic transactions Programmers can do so by adding the transaction safe function attribute to the declarations of these functions and by including this declaration when defining the function In turn GCC then verifies that the code in these functions is safe for atomic transactions and generates code accordingly If the programmer does not follow these constraints and or steps compile time or link time errors occur Note that within a compilation unit GCC detects automatically whether a function is safe for use within transactions and the attributes therefore typically do not need to be added See the draft specification linked above for further details 70 Changes in Version 1 0 GCC s transactional memory support is designed in such a way that it does not decrease the performance of programs that do not use transactions nor the performance of nontransactional code except due to the normal kinds of interference by concurrent threads that use the same resources such as the CPU Transactional Memory support in GCC and libitm is still experimental and both the ABI and API could change in the future if this is required due to the evolution
79. ice Request 13 4 Additional Resources A Changes in Version 1 0 A 1 Changes in GCC 4 7 0 Red Hat Developer Toolset 1 x User Guide 5 6 Table of Contents A 2 A 3 A 1 1 Status and Features A 1 2 Language Compatibility A 1 3 ABI Compatibility A 1 4 Debugging Compatibility A 1 5 Other Compatibility Changes in GDB 7 4 A 2 1 New Features A 2 2 Compatibility Changes Changes in binutils 2 22 52 A 3 1 GNU Linker A 3 2 GNU Assembler A 3 3 Other Binary Tools B Changes in Version 1 1 BA B2 B 3 BA B 5 B 6 C Revis Index Changes in GCC 4 7 2 B 1 1 C 11 Compatibility B 12 Fortran B 1 3 Architecture specific Options Changes in GDB 7 5 Changes in binutils 2 23 51 B 3 1 GNU Linker B 3 2 GNU Assembler B 3 3 Other Binary Tools Changes in elfutils 0 154 Changes in Valgrind 3 8 1 Changes in OProfile 0 154 ion History Red Hat Developer Toolset 1 x User Guide 7 Preface 1 Document Conventions This manual uses several conventions to highlight certain words and phrases and draw attention to specific pieces of information Liberation Fonts set is also used in HTML editions if the set is installed on your system If not alternative but equivalent typefaces are displayed Note Red Hat Enterprise Linux 5 and later includes the Liberation Fonts set by default 1 1 Typographic Conventions Four typographic conventions are used to call attention to specific words and phra
80. ine specifications Improved tracepoint support Multi program debugging Additionally the Red Hat Developer Toolset version of binutils provides these features The new gold linker which is smaller and faster than 1d Note that gold is not the default linker and must be explicitly enabled by using the alternatives command Support for link time optimization LTO in conjunction with GCC Support for build IDs unique numbers to identify executables Support for the IFUNC and UNIQUE symbols that are used by glibc to improve performance Due to dependencies on a particular version of the glibc library these symbols are only available on Red Hat Enterprise Linux 6 Compressed debug sections for smaller debug info files 1 3 Compatibility Red Hat Developer Toolset 1 1 is available for Red Hat Enterprise Linux 5 and 6 both for 32 bit and 64 illustrates the support for binaries built with Red Hat Developer Toolset on a certain version of Red Hat Enterprise Linux when those binaries are run on various other versions of this system 14 Chapter 1 Red Hat Developer Toolset Table 1 1 Red Hat Developer Toolset 1 1 Compatibility Matrix 5 8 5 9 6 0 6 1 6 2 6 3 EUS EUS EUS lt 5 6 Unsupported version of the Red Hat Enterprise Linux host 56 9 O O O Q 8 Q Oo QG O EUS 5 7 Unsupported version of the Red Hat Enterprise Linux host 5 8 Unsupported version of the Red Hat Enterprise Linux host 5 9 O O O 0 O Q O Q 6 0 Unsupported
81. ing64 have been added These pseudo operations be used to generate wide character strings The i386 port now supports the SSE5 instruction set A new pseudo operation reloc has been added This pseudo operation serves as a low level interface for creating relocations A 3 2 2 Compatibility Changes No noteworthy changes that affect compatibility have been made A 3 3 Other Binary Tools A 3 3 1 New Features Red Hat Developer Toolset 1 x User Guide 87 Changes Since Red Hat Enterprise Linux 6 2 The following features have been added since the release of the binutils included in Red Hat Enterprise Linux 6 2 The readelf and obj dump tools can now display the contents of the debug macro sections New dwarf start and dwarf end command line options have been added to the readelf and obj dump tools These options are used by the new Emacs mode see the dwarf mode el file A new interleave width command line option has been added to the obj copy tool to allow the use of the interleave to copy a range of bytes from the input to the output A new dyn syms command line option has been added to the readelf tool This option can be used to dump dynamic symbol table A new tool elfedit has been added to the binutils This tool can be used to directly manipulate ELF format binaries A new command line option addresses or a for short has been added to the addr2line tool This option can be used to display addresses b
82. ion Red Hat Storage Appliance and JBoss Enterprise Middleware evaluations Red Hat Developer Toolset 1 x User Guide 61 Certified Hardware This section has information on what systems components and peripherals Red Hat Enterprise Linux 6 5 and 4 support 12 2 The Deploy Menu Getting Started Downloads DEPLOY k Activate a New Subscription Support Essentials Security Support Figure 12 2 The Deploy Menu In the Deploy menu are resources needed to deploy a development project This includes Getting Started The Getting Started page has links to information to help get up and running with Red Hat subscriptions including product registration information accessing your resources and engaging in global support It also has links to a Red Hat Welcome Kit and a Quick Guide to Red Hat Support Downloads Here is where you can download all that Red Hat offers with descriptions of what each entails Activate a New Subscription After purchasing a Red Hat subscription this is where you go to activate it Note that the Activate a New Subscription section requires you to enter your Red Hat login and password Support Essentials Here you can find a list of articles and group discussions viewable by new posts most popular and recent comments as well as the most recent Red Hat errata Security Red Hat releases errata to address bugs provide enhancements or to fix security vulnerabilities With each erratum an a
83. ions together is unsupported in Developer Toolset 72 Changes in Version 1 0 A 1 1 6 Miscellaneous Ofast is now supported as a general optimization level It operates similar to 03 adds options that can yield better optimized code but in turn might invalidate standards compliance for example f fast math is enabled by Ofast GCC can now inform users about cases in which code generation might be improved by adding attributes such as const pure and noreturn to functions declared in header files Use the Wsuggest attribute const pure noreturn command line option to enable this Assembler code can now make use of a goto feature that allows for jumps to labels in C code A 1 2 Language Compatibility In this section we describe the compatibility between the Red Hat Developer Toolset compilers and the Red Hat Enterprise Linux system compilers at the programming language level for example differences in the implementation of language standards such as C99 or changes to the warnings generated by Wall Some of the changes are a result of bug fixing and some old behaviors have been intentionally changed in order to support new standards or relaxed in standards conforming ways to facilitate compilation or runtime performance Some of these changes are not visible to the naked eye and will not cause problems when updating from older versions However some of these changes are visible and can cause grief to users porting to Re
84. ir respective owners 1801 Varsity Drive Raleigh NC 27606 2072 USA Phone 1 919 754 3700 Phone 888 733 4281 Fax 1 919 754 3701 Red Hat Developer Toolset 1 x User Guide 3 Abstract Red Hat Developer Toolset is a Red Hat offering for developers on the Red Hat Enterprise Linux platform The Red Hat Developer Toolset User Guide provides an overview of this product explains how to invoke and use the Developer Toolset versions of the tools and links to resources with more in depth information 4 Table of Contents Table of Contents Preface 1 Document Conventions 1 1 Typographic Conventions 1 2 Pull quote Conventions 1 3 Notes and Warnings 2 Getting Help and Giving Feedback 2 1 Do You Need Help 2 2 We Need Feedback I Introduction 1 Red Hat Developer Toolset 1 1 About Red Hat Developer Toolset 1 2 Main Features 1 3 Compatibility 14 Getting Access to Red Hat Developer Toolset 1 4 1 Using RHN Classic 1 4 2 Using Red Hat Subscription Management 1 5 Installing Red Hat Developer Toolset 1 6 Updating Red Hat Developer Toolset 1 7 Uninstalling Red Hat Developer Toolset 1 8 Additional Resources Il Development T ools 2 GNU Compiler Collection GCC 2 1 GNU C Compiler 2 1 1 Installing the C Compiler 2 1 2 Using the C Compiler 2 1 3 Running a C Program 2 2 GNU C Compiler 2 2 1 Installing the C Compiler 2 2 2 Using the C Compiler 2 2 3 Running a C Program 2 3 GNU Fortran Com
85. l escalation If an issue is not being resolved appropriately or if you need a more senior resource to attend to it Management escalation If the issue has become more severe or you believe it requires a higher priority 66 Chapter 13 Contacting Global Support Services More information on escalation including contacts is available at 13 3 Re opening a Service Request If more relevant information regarding a closed service request such as the problem reoccurring you can re open it via the Red Hat Customer Portal at Or important _ r r rrr _ In order to re open a service request you need the original service request number 13 4 Additional Resources For more information refer to the resources listed below Online Documentation Red Hat subscription and offers the Red Hat Welcome Kit and Quick Guide to Red Hat Support for download frequent questions about public Red Hat mailing lists Red Hat Developer Toolset 1 x User Guide 67 Changes in Version 1 0 This appendix documents new features and compatibility changes introduced in Red Hat Developer Toolset 1 0 A 1 Changes in GCC 4 7 0 Red Hat Developer Toolset 1 0 is distributed with GCC 4 7 0 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version Below is a comprehensive list of new features and compatibility changes in this release For details on how to use these new features refer
86. le command has been adapted to accept two arguments in the form of start length The source command can now be used to read commands from Python scripts The following changes have been made to the C language support since the release of the GNU Debugger included in Red Hat Enterprise Linux 5 8 Argument dependent lookup ADL now directs function search to the namespaces of its arguments regardless of whether the namespace has been imported In addition to member operators the GNU Debugger can now look up operators that are defined in the global scope defined in a namespace and imported via the using directive implicitly imported from an anonymous namespace or the argument dependent lookup ADL operators Support for printing of static const class members that are initialized in the class definition has been enhanced Support for importing of namespaces has been added The C expression parser has been adapted to handle the cast operators static_cast lt gt dynamic_cast lt gt const_cast lt gt and reinterpret_cast lt gt The following changes have been made to the Python scripting support since the release of the GNU Debugger in Red Hat Enterprise Linux 5 8 The GNU Debugger is now installed with a new directory located at opt rh devtoolset 1 1 root usr share gdb python This directory serves as a standard location for Python scripts written for GDB The Python API has been adapted to provide access to symbols
87. level 2 cache L2 Callgrind Generates a call graph representing the function call history Helgrind Detects synchronization errors in multithreaded C C and Fortran programs that use POSIX threading primitives DRD Detects errors in multithreaded C and C programs that use POSIX threading primitives or any other threading concepts that are built on top of these POSIX threading primitives Massif Monitors heap and stack usage 8 1 Installing Valgrind In Red Hat Developer Toolset Valgrind is provided by the devtoolset 1 1 valgrind package and is automatically installed with devtoolset 1 1 If you intend to use Valgrind to profile parallel programs that use the Message Passing Interface MPI protocol install the devtoolset 1 1 valgrind openmpi package For detailed information about how to install Red Hat Developer Toolset and related packages to your 8 2 Using Valgrind To run any of the Valgrind tools on a program you want to profile type the following at a shell prompt scl enable devtoolset 1 1 valgrind tool tool program option are distributed with Valgrind The argument of the tool command line option must be specified in lower case and if this option is omitted Valgrind uses Memcheck by default For example to run Cachegrind on a program to identify the sources of cache misses type Red Hat Developer Toolset 1 x User Guide 49 scl enable devtoolset 1 1 valgrind tool cachegrind program option
88. line option wL has been added to the readelf tool This option can be used to dump decoded contents of the debug line section Thin archives are now supported Instead of containing object files such archives contain just pathnames pointing to those files A new command line option F has been added to the obj dump tool This option can be used to include file offsets in the disassembly A new command line option c has been added to the readelf tool This option can be used to allow string dumps of archive symbol index The i386 port now supports the SSE5 instruction set A new command line option p has been added to the readelf tool This option can be used to allow string dumps of sections 88 Changes in Version 1 0 A 3 3 2 Compatibility Changes Changes Since Red Hat Enterprise Linux 6 2 No noteworthy changes that affect compatibility have been made Changes Since Red Hat Enterprise Linux 5 8 The following changes have been made since the release of the binutils included in Red Hat Enterprise Linux 5 8 The as needed command line option has been adapted to link in a dynamic library in the following two cases 1 if the dynamic library satisfies undefined symbols in regular objects and 2 if the dynamic library satisfies undefined symbols in other dynamic libraries unless the library is already found in a DT NEEDED entry of one of the libraries that are already linked Red Hat Developer Toolset 1 x User Guide 89
89. ll session with Red Hat Developer Toolset gdb as default scl enable devtoolset 1 1 bash rraummmm To verify the version of gdb you are using at any point type the following at a shell prompt which gdb Red Hat Developer Toolset s gdb executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset gdb gdb v Example 3 3 Running the gdb Utility on the fibonacci Binary File the following at a shell prompt scl enable devtoolset 1 1 gdb fibonacci GNU gdb GDB Red Hat Enterprise Linux 7 4 50 20120120 43 e16 Copyright C 2012 Free Software Foundation Inc License GPLv3 GNU GPL version 3 or later http gnu org licenses gpl html This is free software you are free to change and redistribute it There is NO WARRANTY to the extent permitted by law Type show copying and show warranty for details This GDB was configured as x86 64 redhat linux gnu For bug reporting instructions please see http www gnu org software gdb bugs gdb 3 4 Listing Source Code To view the source code of the program you are debugging run the following command Red Hat Developer Toolset 1 x User Guide 31 list Before you start the execution of the program you are debugging gdb displays first ten lines of the source code and any subsequent use of this command lists another ten lines Once
90. ls menu titles and sub menu titles For example Choose System Preferences Mouse from the main menu bar to launch Mouse Preferences In the Buttons tab click the Left handed mouse check box and click Close to switch the primary mouse button from the left to the right making the mouse suitable for use in the left hand To insert a special character into a gedit file choose Applications Accessories Character Map from the main menu bar Next choose Search Find from the 8 Preface Character Map menu bar type the name of the character in the Search field and click Next The character you sought will be highlighted in the Character Table Double click this highlighted character to place it inthe Text to copy field and then click the Copy button Now switch back to your document and choose Edit Paste from the gedit menu bar The above text includes application names system wide menu names and items application specific menu names and buttons and text found within a GUI interface all presented in proportional bold and all distinguishable by context Mono spaced Bold Italic or Proportional Bold Italic Whether mono spaced bold or proportional bold the addition of italics indicates replaceable or variable text Italics denotes text you do not input literally or displayed text that changes depending on circumstance For example To connect to a remote machine using ssh type ssh username domain name at a shell prom
91. lset 1 1 package by typing the following at a shell prompt as root Red Hat Developer Toolset 1 x User Guide 17 yum install devtoolset 1 1 This installs the GNU Compiler Collection GNU Debugger binutils the sc 1 utility and other dependent packages to the system You can also install any of the additional packages listed in the Package Manifest section of the Red Hat Developer Toolset 1 1 Release Notes by running the command in the following form as root yum install package name For example to install libitm and devtoolset 1 1 gdb gdbserver type yum install libitm devtoolset 1 1 gdb gdbserver To install debugging information for any of the Red Hat Developer Toolset packages run as root debuginfo install package name 1 6 Updating Red Hat Developer Toolset Before updating an existing installation of Red Hat Developer Toolset on your system make sure the devtoolset 1 0 gcc debuginfo package is not installed To do so type the following at a shell prompt as root yum remove devtoolset 1 0 gcc debuginfo Then run the following command as root to update your Red Hat Enterprise Linux installation yum update This updates all packages on your Red Hat Enterprise Linux system including the Red Hat Developer Toolset versions of the GNU Compiler Collection GNU Debugger binutils and other dependent packages Note that if you need additional packages with debugging information for any of the Red Hat Developer Toolset packages such as de
92. ly a factor of 5 as compared with the previous version of Valgrind A new command line option fullpath after has been added This option can be used to display directory names for source files in error messages and is combined with a flexible mechanism for specifying which parts of the paths should be shown A new command line option require text symbol has been added This option stops the execution if a specified symbol is not found in a given shared object when loaded into the process As a result working with function intercepting and wrapping is now safer and more reliable Valgrind now implements more reliable stack unwinding on amd64 linux particularly in the presence of function wrappers and with gcc 4 5 compiled code Valgrind now implements modest scalability performance improvements for very large long running applications Valgrind now provides improved support for analyzing programs that are running in Wine Users can now include the valgrind valgrind h valgrind memcheck h and valgrind drd h header files in Windows programs that are compiled with MinGW or one of the Microsoft Visual Studio compilers B 6 Changes in OProfile 0 154 Red Hat Developer Toolset 1 1 is distributed with OProfile 0 9 7 Below is a comprehensive list of new features in this release Changes Since Red Hat Enterprise Linux 6 3 No noteworthy changes have been made Changes Since Red Hat Enterprise Linux 5 9 The following features have
93. mTap In Red Hat Developer Toolset SystemTap is provided by the devtoolset 1 1 systemtap package and is In order to place instrumentation into the Linux kernel SystemT ap may also require installation of additional packages with debugging information To determine which packages to install run the stap prep utility as follows scl enable devtoolset 1 1 stap prep Note that if you execute this command as the root user the utility automatically offers the packages for installation For more information on how to install these packages on your system refer to the Red Hat Enterprise Linux SystemTap Beginners Guide 7 2 Using SystemTap To execute any of the tools that are part of SystemT ap type the following at a shell prompt scl enable devtoolset 1 1 tool option 46 Chapter 7 SystemTap that are distributed with SystemT ap For example to run the stap tool to build an instrumentation module type scl enable devtoolset 1 1 stap option argument Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset SystemT ap as default scl enable devtoolset 1 1 bash rau To verify the version of SystemT ap you are using at any point type the following at a shell prompt which stap Red Hat Devel
94. ne option Additionally GNU Fortran now provides preliminary support for multiple images via an MPI based coarray communication library Note that the library version is not yet usable as remote coarray access is not yet possible The STOP and ERROR STOP statements have been updated to support all constant expressions The CONT IGUOUS attribute is now supported Use of ALLOCAT E with the MOLD argument is now supported The STORAGE SIZE intrinsic inquiry function is now supported The NORM2 and PARITY intrinsic functions are now supported The following bit intrinsics have been added the POPCNT and POPPAR bit intrinsics for counting the number of 1 bits and returning the parity the BGE BGT BLE and BLT bit intrinsics for bitwise comparisons the DSHIFTL and DSHIFTR bit intrinsics for combined left and right shifts the MASKL and MASKR bit intrinsics for simple left and right justified masks the MERGE_BITS bit intrinsic for a bitwise merge using a mask 92 Changes in Version 1 1 the SHIFTA SHIFTL and SHIFTR bit intrinsics for shift operations the transformational bit intrinsics IALL IANY and IPARIT Y The EXECUTE COMMAND LINE intrinsic subroutine is now supported The IMPURE attribute for procedures is now supported This allows the use of ELEMENTAL procedures without the restrictions of PURE Null pointers including NULL and unallocated variables can now be used as an actual argument to optional non pointer non allocatable dummy
95. new command line option free is writezno yes has been added to Helgrind This option allows you to enable detection of races where one thread accesses heap memory but another one frees it without any coordinating synchronization event The option is set to no by default DRD can now produce XML output Support for delayed thread deletion has been added to DRD to detect race conditions that occur close to the end of a thread the join list vol option The exp ptrcheck tool has been renamed to exp sgcheck Stack and global Array Checking The exp sgcheck tool has been reduced in scope to improve performance and remove checking that Memcheck does better In particular the ability to check for overruns for stack and global arrays is unchanged but the ability to check for overruns of heap blocks has been removed Valgrind now provides an embedded GDB server which allows you to control a Valgrind run from GDB and perform GDB operations such as single stepping breakpoints examining data and so on Tool specific functionality is also available and it is now possible to query the definedness state of variables or memory from within GDB when running Memcheck add arbitrarily large memory watchpoints etc To use the GDB server start Valgrind with the vgdb error 0 command line option and follow the on screen instructions Red Hat Developer Toolset 1 x User Guide 99 Support for unfriendly self modifying code has been improved A new comman
96. nments Part IV Integrated Development Environments Red Hat Developer Toolset 1 x User Guide 55 Chapter 10 Eclipse Eclipse is a powerful development environment that provides tools for each phase of the development process It integrates a variety of disparate tools into a unified environment to create a rich development experience provides a fully configurable user interface and features a pluggable architecture that allows for extension in a variety of ways For instance the Valgrind plug in allows programmers to perform memory profiling otherwise performed on the command line through the Eclipse user interface Eclipse provides a graphical development environment alternative to traditional interaction with command line tools and as such it is a welcome alternative to developers who do not want to use the command line interface The traditional mostly command line based Linux tools suite such as gcc or gdb and Eclipse offer two distinct approaches to programming File Edit Source Refactor Navigate Search Project Run Window Help CS amp amp Ov dv Gy 7 Pisa m v 73 Debug 18 Package Explorer 3 A N Fibonacci java amp A 8 Outline 23 ELI w public class Fibonacci so 3 public static void main String args A ax s gt amp Fibonacci long a 6 v Fibonacci long b 1 long sum Bmain String vo vi while b lt Integer MAX VALUE Systen out print b sum a
97. nt This allows you to run a shell session with Red Hat Developer Toolset 1d as default d scl enable devtoolset 1 1 bash rrauuA To verify the version of 1d you are using at any point type the following at a shell prompt which 1d Red Hat Developer Toolset s 1d executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset 1d ld v 4 4 Using Other Binary Tools The binutils provide many binary tools other than a linker and assembler For a complete list of these 38 Chapter 4 binutils To execute any of the tools that are part of binutils run the command as follows scl enable devtoolset 1 1 tool option file name distributed with binutils For example to use the obj dump tool to inspect an object file type scl enable devtoolset 1 1 objdump option object file Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset binary tools as default scl enable devtoolset 1 1 bash rraaunnnA O To verify the version of binutils you are using at any point type the following at a shell prompt which objdump Red Hat Developer Toolset s obj dump executable path will b
98. nt instructions on AMD processors mpopcnt Enables the use of the popcnt instruction on both AMD and Intel processors When using the x87 floating point unit GCC now generates code that conforms to ISO C99 in terms of handling of floating point excess precision This can be enabled by fexcess precision standard and disabled by fexcess precision fast This feature is enabled by default when using standards conformance options such as std c99 A 1 1 5 Link time Optimization Link time optimization LT O is a compilation technique in which GCC generates an internal representation of each compiled input file in addition to the native code and writes both to the output object file Subsequently when several object files are linked together GCC uses the internal representations of the compiled code to optimize inter procedurally across all the compilation units This can potentially improve the performance of the generated code for example functions defined in one file can potentially be inlined when called in another file To enable LTO the f1to option needs to be specified at both compile time and link time For further details including interoperability with linkers and parallel execution of LTO refer to the documentation for LTO will only apply to code generated by the same version of GCC rrauA Use of Link time Optimization with debug generation is not yet supported in gcc 4 7 and so use of the f1to and the g opt
99. nvenience functions located in data directory python gdb command and data directory python gdb function are now automatically loaded on GDB start up Blocks now provide four new attributes global block static block is static and is global The gdb breakpoint function has been deprecated in favor of gdb breakpoints A new class gdb FinishBreakpoint is provided Type objects for struct and union types now allow access to the fields using standard Python dictionary mapping methods A new event gdb new objfile has been added A new function deep items has been added to the gdb types module The function gdb Write now accepts an optional keyword stream Parameters can now be sub classed in Python which allows for implementation of the get set doc and get show doc functions Symbols Symbol Table Symbol Table and Line Object Files Inferior Inferior Thread Blocks and Block Iterator APIs now have an is valid method Breakpoints can now be sub classed in Python which allows for implementation of the stop function that is executed each time the inferior reaches that breakpoint A new function gdb lookup global symbol has been added This function can be used to look up a global symbol GDB values in Python are now callable if the value represents a function A new module gdb types has been added A new module gdb printing has been added New commands info pretty printers enable pretty printer anddisable pretty printer hav
100. o create and comment on discussions to interact with other customers Red Hat support staff and certified engineers Note that the Groups section requires you to enter your Red Hat login and password Videos Red Hat Developer Toolset 1 x User Guide 63 A number of videos on how to get vital solutions useful tips product demonstrations and inside information can be accessed from here You can also rate and comment on all of the videos Tech Briefs Tech briefs provide practical advice to help solve real world problems with Red Hat products Each tech brief provides a detailed use case covering best practices how to instructions or detailed discussions on how to use Red Hat technology effectively and are reviewed and tested by Red Hat engineers Source This is the kernel source browser and contains links to all the kernel sources broken into each individual patch unlike the kernel srpm which is shipped as one big patch Note that the Source section requires you to enter your Red Hat login and password Support Cases This is where users can view all their support cases make changes or view any updates Note that the Support Cases section requires you to enter your Red Hat login and password 64 Chapter 13 Contacting Global Support Services Chapter 13 Contacting Global Support Services Unless you have a Self Support subscription when both the Red Hat Documentation website and Customer Portal fail to provide the answers to y
101. ol that allows users to monitor the activities of the entire system without needing to instrument recompile install and reboot It is programmable with a custom scripting language which gives it expressiveness to trace filter and analyze and reach to look into the running kernel and applications SystemT ap can monitor various types of events such as function calls within the kernel or applications timers tracepoints performance counters and so on Some included example scripts produce output similar to netstat ps top and iostat others include pretty printed function callgraph traces or tools for working around security bugs Red Hat Developer Toolset is distributed with SystemTap 1 8 Table 7 1 Tools Distributed with SystemTap for Red Hat Developer Toolset Name Description stap Translates probing instructions into C code builds a kernel module and loads it into a running Linux kernel staprun Loads unloads attaches to and detaches from kernel modules built with the stap utility stapsh Serves as a remote shell for SystemT ap stap prep Determines and if possible downloads the kernel information packages that are required to run SystemT ap stap merge Merges per CPU files This script is automatically executed when the stap utility is executed with the b command line option stap report Gathers important information about the system for the purpose of reporting a bug in SystemT ap 7 1 Installing Syste
102. ollections an additional set of developer tools is installed into the opt directory and is explicitly enabled by the user on demand using the supplied sc1 utility 1 2 Main Features Red Hat Developer Toolset 1 1 provides current versions of the following tools GNU Compiler Collection GCC version 4 7 2 GNU Debugger GDB version 7 5 binutils version 2 23 51 elfutils version 0 154 dwz version 0 7 Red Hat Developer Toolset 1 x User Guide 13 SystemTap version 1 8 Valgrind version 3 8 1 OProfile version 0 9 7 In particular the Red Hat Developer Toolset version of the GNU Compiler Collection GCC provides the following features Support for the Fortran programming language Experimental support for the C 11 standard Experimental support for C 11 atomic types and Transactional Memory Improved support for link time optimization LT O Improved support for interprocedural optimization New Ofast general optimization level New string length optimization pass Various compile time and memory usage improvements Support for OpenMP 3 1 an API specification for parallel programming Optimization for various new Intel and AMD processors The version of the GNU Debugger GDB included in Red Hat Developer Toolset provides the following features Improved and expanded support for Python scripting Improved handling of C debugee executables Improved inferior control commands Improved support for ambiguous l
103. ommand info vtbl has been added This command allows you to show the virtual method tables for C and Java objects A new command explore has been added It supports two subcommands explore value and explore type and allows you to recursively explore values and types of expressions Note that this command is only available with Python enabled GDB A new command dprintf location format args has been added This command allows you to create a dynamic printf type breakpoint which performs a printf like operation and then resumes program execution New set print symbol and show print symbol commands have been added These commands allow you to control whether GDB attempts to display the symbol if any that corresponds to addresses it prints This functionality is enabled by default but you can restore the previous behavior by running the set print symbol off command New set breakpoint condition evaluation and show breakpoint condition evaluation commands have been added These commands allow you to control whether breakpoint conditions are evaluated by GDB the host option or by gdbserver the target option The default option auto chooses the most efficient available mode New set dprintf style gdb call agent and show dprintf style commands have been added These commands allow you to control the way in which a dynamic printf is performed the gdb option requests a GDB printf command call causes dprintf to call a function in the inferi
104. ommand line option no export dynamic has been added This option can be used to undo the effect of the E and export dynamic options A new command line option warn alternate em has been added This option can be used to display a warning if an ELF format object file uses an alternate machine code A new linker script function REGION ALIAS has been added This function can be used to create alias names of memory regions A new command line option Ttext segment address has been added for ELF based targets This option can be used to set the address of the first byte of the text segment Red Hat Developer Toolset 1 x User Guide 85 A new linker script command INSERT has been added This command can be used to augment the default script In a linker script input section it is now possible to specify a file within an archive by using the archive file syntax The sort common command line option now accepts ascending and descending as optional arguments This can be used to specify which sorting order to use A new command line option build id has been added for ELF based targets This option can be used to generate a unique per binary identifier embedded in a note section A new command line option default script file_name or dT file name has been added This option can be used to specify a replacement for the built in linker script A new command line option Bsymbolic functions has been added When creating a shared libra
105. onnections for example gdb target remote ssh myhost gdbserver hello GDB is now able to print flag enums In a flag enum all enumerator values have no bits in common when pairwise AND ed When GDB prints a value whose type is a flag enum GDB shows all the constants for example for enum E ONE 1 TWO 2 gdb print enum E 3 1 ONE TWO The file name part of a linespec now matches trailing components of a source file name For example break gcc expr c 1000 now sets a breakpoint in the build gcc expr c file but not in build libcpp expr c The info proc and generate core file commands now work on remote targets connected to gdbserver The command info catch has been removed The Ada specific catch exception and catch assert commands now accept conditions at the end of the command The info static tracepoint marker command now works on native targets with an in process agent IA Changes in Version 1 1 GDB can now set breakpoints on inline functions The gdb index section has been updated to include symbols for inline functions By default GDB now ignores older gdb index sections until their gdb index sections can be recreated The new command set use deprecated index sections on causes GDB to use any older gdb index sections it finds If this option is set the ability to set breakpoints on inline functions is lost in symbol files with older gdb index sections The gdb index section has also been
106. oper Toolset s stap executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset SystemT ap stap V 7 3 Additional Resources A detailed description of SystemT ap and its features is beyond the scope of this book For more information refer to the resources listed below Installed Documentation stap 1 The manual page for the stap command provides detailed information on its usage as well as references to other related manual pages To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 1 1 man stap staprun 8 The manual page for the staprun command provides detailed information on its usage To display the manual page for the version included in Red Hat Developer Toolset type scl enable devtoolset 1 1 man staprun SystemTap Tapset Reference Manual HT ML documentation on the most common tapset definitions is located at opt rh devtoolset 1 1 root usr share doc devtoolset 1 1 systemtap client 1 8 index html Online Documentation Red Hat Developer Toolset 1 x User Guide 47 Red Hat Enterprise Linux 5 provides an introduction to SystemT ap and its usage documentation on SystemT ap as well as numerous examples of SystemT ap scripts See Also and memory management problems such as the use of uninitialized memory improper allocation and freeing o
107. or and agent requests that the target agent such as gdbserver does the printing New set dprintf function expression show dprintf function set dprintf channel expression and show dprintf channel commands have been added These Red Hat Developer Toolset 1 x User Guide 95 commands allow you to set the function and optional first argument to the call when using the call style of dynamic printf New set disconnected dprintf on off and show disconnected dprintf commands have been added These commands allow you to control whether agent style dynamic printfs continue to be in effect after GDB disconnects The following changes have been made to the Python scripting support since the release of the GNU Debugger included in Red Hat Enterprise Linux 6 3 and 5 9 GDB commands implemented in Python can now be put in the gdb COMMAND USER command class The maint set python print stack on Joff command has been removed and replaced by set python print stack A new class gdb printing FlagEnumerationPrinter has been added This class can be used to apply f lag enum style pretty printing to enums The gdb 1ookup symbol function now works correctly when there is no current frame The gdb Symbol object now has an additional attribute line This attribute holds the line number in the source at which the symbol was defined The gdb Symbol object now has an additional attribute needs frame and a new method value The needs frame attribute indicates whethe
108. ound you can use the Wno error unused but set variable or Wno error unused but set parameter command line option The Wenum compare option causes GCC to report a warning when values of different enum types are being compared Previously this option only worked for C programs but now it works for C as well This warning is enabled by Wall and may be avoided by using a type cast Casting integers to larger pointer types now causes GCC to display a warning by default To disable these warnings use the Wno int to pointer cast option which is available for both C and C Conversions between NULL and non pointer types now cause GCC to report a warning by default Previously these warnings were only displayed when explicitly using Wconversion To disable these warnings use the new Wno conversion null command line option GCC can now warn when a class that has virtual functions and a non virtual destructor is destroyed by using delete This is unsafe to do because the pointer might refer to a base class that does not have a virtual destructor The warning is enabled by Wall and by a new command line option Wdelete non virtual dtor New Wc 11 compat and Wc 0x compat options are now available These options cause GCC to display a warning about C constructs whose meaning differs between ISO C 1998 and ISO C 2011 such as identifiers in ISO C 1998 that are keywords in ISO C 2011 This warning is enabled by Wall and enables
109. our questions you can contact Global Support Services GSS 13 1 Gathering Required Information Several items of information should be gathered before contacting GSS Background Information Ensure you have the following background information at hand before calling GSS Hardware type make and model on which the product runs Software version Latest upgrades Any recent changes to the system An explanation of the problem and the symptoms Any messages or significant information about the issue rraummmm If you ever forget your Red Hat login information it can be recovered at Diagnostics The diagnostics report for Red Hat Enterprise Linux is required as well This report is also known as a sosreport and the program to create the report is provided by the sos package To install the sos package and all its dependencies on your system type the following at a shell prompt as root yum install sos To generate the report run as root sosreport Account and Contact Information In order to help you GSS requires your account information to customize their support as well contact information to get back to you When you contact GSS ensure you have your Red Hat customer number or Red Hat Network RHN login name Company name Contact name Preferred method of contact phone or email and contact information phone number or email address Red Hat Developer Toolset 1 x User Guide 6
110. ource files it is common to compile an object file for each of the source files first and then link these object files together This way when you change a single source file you can recompile only this file without having to compile the entire project To compile an object file on the command line run the following command scl enable devtoolset 1 1 gcc o object file c source file This creates an object file named object_file if the o option is omitted the compiler creates a file named after the source file with the o file extension To link object files together and create a binary file run scl enable devtoolset 1 1 gcc o output file object file Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset gcc as default scl enable devtoolset 1 1 bash Red Hat Developer Toolset 1 x User Guide 21 To verify the version of gcc you are using at any point type the following at a shell prompt which gcc Red Hat Developer Toolset s gcc executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset gcc N gcc v Or important Some newer library features are statically linked into applications built with Red
111. pannotate Generates an annotated source file or assembly listing form the profiling data oparchive Generates a directory containing executable debug and sample files opgprof Generates a summary of a profiling session in a format compatible with gprof ophelp Displays a list of available events opimport Converts a sample database file from a foreign binary format to the native format opjitconv Converts a just in time JIT dump file to the Executable and Linkable Format ELF opreport Generates image and symbol summaries of a profiling session 9 1 Installing OProfile In Red Hat Developer Toolset OProfile is provided by the devtoolset 1 1 oprofile package and is 9 2 Using OProfile To run any of the tools that are distributed with OProfile type the following at a shell prompt as root scl enable devtoolset 1 1 tool option are distributed with Valgrind For example to use the ophelp command to list available events in the XML format type 52 Chapter 9 OProfile scl enable devtoolset 1 1 ophelp X Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset OProfile as default scl enable devtoolset 1 1 bash CO To verify the version of OProfile you are using at any point type the following at a sh
112. piler 2 3 1 Installing the Fortran Compiler 2 3 2 Using the Fortran Compiler 2 3 3 Running a Fortran Program 2 4 Additional Resources 3 GNU Debugger GDB 3 1 Installing the GNU Debugger 3 2 Preparing a Program for Debugging 3 3 Running the GNU Debugger 3 4 Listing Source Code 3 5 Setting Breakpoints 3 6 Starting Execution 3 7 Displaying Current Values 3 8 Continuing Execution 3 9 Additional Resources 4 binutils 4 1 Installing binutils 4 2 Using the GNU Assembler 4 3 Using the GNU Linker 4 4 Using Other Binary Tools 4 5 Additional Resources 5 elfutils 5 1 Installing elfutils 5 2 Using elfutils 5 3 Additional Resources 6 dwz 6 1 Installing dwz 6 2 Using dwz 6 3 Additional Resources lll Performance Monitoring Tools 7 SystemTap 7 1 Installing SystemT ap 7 2 Using SystemT ap 7 3 Additional Resources 8 Valgrind 8 1 Installing Valgrind 8 2 Using Valgrind 8 3 Additional Resources 9 OProfile 9 1 Installing OProfile 9 2 Using OProfile 9 3 Additional Resources IV Integrated Development Environments 10 Eclipse 10 1 Installing Eclipse 10 2 Running Eclipse 10 3 Additional Resources V Getting Help 11 Accessing Red Hat Product Documentation 12 Accessing the Customer Portal 12 1 The Plan Menu 12 2 The Deploy Menu 12 3 The Connect Menu 13 Contacting Global Support Services 13 1 Gathering Required Information 13 2 Escalating an Issue 13 3 Re opening a Serv
113. piler creates a file named after the source file with the o file extension To link object files together and create a binary file run scl enable devtoolset 1 1 gfortran o output file object file Note that you can execute any command using the sc1 utility causing it to be run with the Red Hat Developer Toolset binaries used in preference to the Red Hat Enterprise Linux system equivalent This allows you to run a shell session with Red Hat Developer Toolset gfortran as default scl enable devtoolset 1 1 bash Red Hat Developer Toolset 1 x User Guide To verify the version of gfortran you are using at any point type the following at a shell prompt which gfortran Red Hat Developer Toolset s gfortran executable path will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset gfortran 1 gfortran v 25 rraumm Some newer library features are statically linked into applications built with Red Hat Developer Toolset to support execution on multiple versions of Red Hat Enterprise Linux This adds a small additional security risk as normal Red Hat Enterprise Linux errata would not change this code If the need for developers to rebuild their applications due to such an issue arises Red Hat will signal this via a security erratum Developers are strongly advised not to statically link their entire
114. pt If the remote machine is example com and your username on that machine is john type ssh john example com The mount o remount file system command remounts the named file system For example to remount the home file system the command is mount o remount home To see the version of a currently installed package use the rpm q package command It will return a result as follows package version release Note the words in bold italics above username domain name file system package version and release Each word is a placeholder either for text you enter when issuing a command or for text displayed by the system Aside from standard usage for presenting the title of a work italics denotes the first use of a new and important term For example Publican is a DocBook publishing system 1 2 Pull quote Conventions Terminal output and source code listings are set off visually from the surrounding text Output sent to a terminal is set in mono spaced roman and presented thus books Desktop documentation drafts mss photos stuff svn books tests Desktop1 downloads images notes scripts svgs Source code listings are also set in mono spaced roman but add syntax highlighting as follows Red Hat Developer Toolset 1 x User Guide package org jboss book jca ex1 import javax naming InitialContext public class ExClient public static void main String args throws Exception InitialContext iniCtx new InitialContext
115. r 2 the injected class name cannot be used as an argument for a template parameter 76 Changes in Version 1 0 In either of these cases the code can be fixed by adding a nested name specifier to explicitly name the template The first can be worked around with fno access control the second is only rejected with pedantic A 1 2 3 CIC Warnings GCC 4 7 0 adds a number of new warnings that are either enabled by default or by using the wall option Although these warnings do not result in compilation failure on their own often Wall is used in conjunction with Werror causing these warnings to act like errors This section provides a list of these new or newly enabled warnings Unless noted otherwise these warnings apply to both C and C The behavior of the wall command line option has changed and now includes the new warning flags Wunused but set variable and with Wall Wextra Wunused but set parameter This may result in new warnings in code that compiled cleanly with previous versions of GCC For example consider the following code void fn void int foo foo bar foo is never used j The following diagnostic output will be produced warning variable foo set but not used Wunused but set variable To fix this issue first see if the unused variable or parameter can be removed without changing the result or logic of the surrounding code If not annotate it with 1 attribute unused As a workar
116. r the symbol requires a frame to compute its value and the value method computes the symbol s value The gdb Value object now has a new method referenced value This method can be used to dereference a pointer as well as C reference values The gdb Symtab object now has two new methods global blockand static block These methods return the global and static blocks as gdb Block objects of the underlying symbol table respectively A new method gdb find pc line returns the gdb Symtab and line object associated with a PC value The gdb Symtab and line object now has an additional attribute last This attribute holds the end of the address range occupied by the code for the current source line B 3 Changes in binutils 2 23 51 Red Hat Developer Toolset 1 1 is distributed with binutils 2 23 51 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version Below is a comprehensive list of new features in this release B 3 1 GNU Linker The following features have been added since the release of binutils included in Red Hat Enterprise Linux 6 3 and 5 9 A new SORT NONE keyword has been added to the linker script language This keyword can be used to disable section sorting A new linker provided symbol ehdr start has been added When producing ELF output this symbol points to the ELF file header and nearby program headers in the program s memory image B 3 2 GNU Assembler Th
117. rint DW OP GNU entry value and DW AT GNU call site families of DIE attributes eu strip now recognizes a new command line option reloc debug sections Changes Since Red Hat Enterprise Linux 5 9 In addition to the above changes the following features have been added since the release of elfutils included in Red Hat Enterprise Linux 5 9 DWARF 4 is now supported Support for DW OP GNU implicit pointer STB GNU UNIQUE was added libdwfl now supports automatic decompression of files compressed with gzip bzip2 and lzma and of Linux kernel images made with gzip bzip2 or 1zma Files named with compression suffixes are searched for Linux kernel images Core file support was improved Support has been added for decoding DWARF CFI into location description form Support has been added for some new DWARF 3 expression operations which were previously omitted A new function dwf 1 dwarf line has been added eu elfcmp has a new flag ignore build id to ignore differing build ID bits The new flag 1 verbose prints all differences eu strip now recognizes a new flag strip sections to remove section headers entirely libdw has new functions dwarf next unit dwarf offdie types dwarf lineisa dwarf linediscriminator dwarf lineop index Red Hat Developer Toolset 1 x User Guide 97 dwarf getlocation implicit pointer and dwarf aggregate size eu addr2line recognizes F flags to print more DWARF line information details libelf no
118. rise Linux Developer Suite RH3482727 Red Hat Enterprise Linux Developer Workstation Professional RH3413336 Red Hat Enterprise Linux Developer Workstation Enterprise RH3414706 30 day Self Supported Red Hat Enterprise Linux Developer Workstation Evaluation RH3474212 60 day Supported Red Hat Enterprise Linux Developer Workstation Evaluation RH3437268 90 day Supported Red Hat Enterprise Linux Developer Workstation Evaluation SER0402 1 year Unsupported Partner Evaluation Red Hat Enterprise Linux SER0403 1 year Unsupported Red Hat Advanced Partner Subscription 1 4 1 Using RHN Classic If your system is registered with RHN Classic complete the following steps to subscribe to Red Hat Developer Toolset 1 Display a list of all channels that are available to you in order to determine the exact name of the Red Hat Developer Toolset channel To do so type the following at a shell prompt as root rhn channel available channels The name of the channel depends on the specific version of Red Hat Enterprise Linux you are using and is in the rhel architecture variant dts version format where architecture is the system s CPU architecture X86 64 or 1386 variant is the Red Hat Enterprise Linux system variant server or workstation and version is the Red Hat Enterprise Linux system version 5 or 6 2 Subscribe the system to the Red Hat Developer Toolset channel by running the following command as root rhn channel add channel channel nam
119. rsion of binutils Red Hat Developer Toolset is distributed with binutils 2 23 51 This version is more recent than the version included in Red Hat Enterprise Linux and provides numerous bug fixes and enhancements including the new gold linker several new command line options improvements to the linker script language and support for link time optimization compressed debug sections and new instruction sets Table 4 1 Tools Included in binutils for Red Hat Developer Toolset Name Description addr2line Translates addresses into file names and line numbers ar Creates modifies and extracts files from archives as The GNU assembler c filt Decodes mangled C symbols elfedit Examines and edits ELF files gprof Display profiling information ld The GNU linker ld bfd An alternative to the GNU linker ld gold A new ELF linker nm Lists symbols from object files objcopy Copies and translates object files objdump Displays information from object files ranlib Generates an index to the contents of an archive to make access to this archive faster readelf Displays information about ELF files size Lists section sizes of object or archive files strings Displays printable character sequences in files strip Discards all symbols from object files 4 1 Installing binutils In Red Hat Developer Toolset binutils are provided by the devtoolset 1 1 binutils package and are 4 2 Using the GNU Assembler To produce an obje
120. ry this option will cause references to global function symbols to be bound to the definitions with the shared library if such exist The new command line options dynamic list cpp new and dynamic list data have been added which can be used to modify the dynamic list A 3 1 2 Compatibility Changes Changes Since Red Hat Enterprise Linux 6 2 The following changes have been made since the release of the binutils included in Red Hat Enterprise Linux 6 2 The copy dt needed entries command line option is no longer enabled by default Instead no copy dt needed entries is now the default option Evaluation of linker script expressions has been significantly improved Note that this can negatively affect scripts that rely on undocumented behavior of the old expression evaluation Changes Since Red Hat Enterprise Linux 5 8 In addition to the above changes the following changes have been made since the release of the binutils included in Red Hat Enterprise Linux 5 8 The add needed command line option has been renamed to copy dt needed entries in order to avoid confusion with the as needed option For GNU Linux systems the linker no longer processes any relocations made against symbols of the STT GNU IFUNC type Instead it emits them into the resulting binary for processing by the loader rra u The implementation of this feature depends on capabilities only found in newer versions of the glib
121. s As a result of this some code with undefined behavior will now break When an extern declaration within a function does not match a declaration in the enclosing context G now properly declares the name within the namespace of the function rather than the namespace which was open just before the function definition G now implements the proposed resolution of the C standard s core issue 253 Default initialization is allowed if it initializes all subobjects and code that fails to compile can be fixed by providing an initializer such as struct A A Y Seks DATE CERTE EY const B b B Access control is now applied to typedef names used in a template which may cause G to reject some ill formed code that was accepted by earlier releases The fno access control option can be used as a temporary workaround until the code is corrected G now implements the C standard s core issue 176 Previously G did not support using the injected class name of a template base class as a type name and lookup of the name found the declaration of the template in the enclosing scope Now lookup of the name finds the injected class name which can be used either as a type or as a template depending on whether or not the name is followed by a template argument list As a result of this change some code that was previously accepted may be ill formed because 1 the injected class name is not accessible because it is from a private base o
122. se Linux 5 or 6 system toolchain GCC Red Hat recommends use of this default std c 98 mode for production software development OP important Use of C 11 features in your application requires careful consideration of the above ABI compatibility information those built with the Red Hat Enterprise Linux v5 x v6 x toolchain particularly o a files the Red Hat Developer Toolset toolchain should be used for any linkage This ensures any newer library features provided only by Developer Toolset are resolved at link time A new standard mangling for SIMD vector types has been added to avoid name clashes on systems with vectors of varying length By default the compiler still uses the old mangling but emits aliases with the new mangling on targets that support strong aliases Wabi will now display a warning about code that uses the old mangling A 1 3 2 Miscellaneous GCC now optimizes calls to various standard C string functions such as strlen strchr strcpy strcat and stpcpy as well as their respective FORTIFY SOURCE variants by transforming them into custom faster code This means that there might be fewer or other calls to those functions than in the original source code The optimization is enabled by default at 02 or higher optimization levels It is disabled when using fno optimize strlen or when optimizing for size When compiling for 32 bit GNU Linux and not optimizing for size fomit frame pointer is now enabled by
123. ses These conventions and the circumstances they apply to are as follows Mono spaced Bold Used to highlight system input including shell commands file names and paths Also used to highlight keys and key combinations For example To see the contents of the file my next bestselling novel in your current working directory enter the cat my next bestselling novel command at the shell prompt and press Enter to execute the command The above includes a file name a shell command and a key all presented in mono spaced bold and all distinguishable thanks to context Key combinations can be distinguished from an individual key by the plus sign that connects each part of a key combination For example Press Enter to execute the command Press Ctr1 Alt F2 to switch to a virtual terminal The first example highlights a particular key to press The second example highlights a key combination a set of three keys pressed simultaneously If source code is discussed class names methods functions variable names and returned values mentioned within a paragraph will be presented as above in mono spaced bold For example File related classes include filesystem for file systems f ile for files and dir for directories Each class has its own associated set of permissions Proportional Bold This denotes words or phrases encountered on a system including application names dialog box text labeled buttons check box and radio button labe
124. symbol tables program spaces breakpoints inferiors threads and frame s code blocks Users are now also allowed to create custom GDB parameters from the API and manipulate them by using the set and show commands New functions gdb target_charset gdb target wide charset gdb progspaces gdb current_progspace and gdb string_to_argv have been added Anew exception gdb GdbError has been added The GNU Debugger now searches pretty printers in the current program space The GNU Debugger can now enable or disable pretty printers individually 9 j 2 Red Hat Developer Toolset 1 x User Guide 83 The GNU Debugger has been adapted to look for names of Python scripts to automatically load in a special section named debug gdb scripts A 2 2 Compatibility Changes Changes Since Red Hat Enterprise Linux 6 2 The following changes have been made since the release of the GNU Debugger included in Red Hat Enterprise Linux 6 2 A new command info auto load has been added and can be used to display the status of various automatically loaded files The info auto load gdb scripts command lists automatically loaded canned sequences of commands info auto load python scripts displays the status of automatically loaded Python scripts info auto load local gdbinit displays whether a local gdbinit file in the current working directory is loaded and info auto load libthread db displays whether the inferior specific thread debugging shared library is load
125. ted to disable pagination and queries Direct support for the reading and writing byte word and double word x86 general purpose registers such as al has been added The commands command now accepts a range of breakpoints as an argument The rbreak command now accepts a file name as part of its argument This can be used to limit the functions selected by the supplied regular expression to those that are defined in the specified file Support for multi program sometimes referred to as multi executable or multi exec debugging has been added In particular the GNU Debugger now supports the following commands The add inferior command can be used to add a new inferior The clone inferior command can be used to create a copy of an inferior with the same executable loaded The remove inferior command accepts an inferior ID as an argument and can be used to remove an inferior Support for trace state variables has been added In particular the GNU Debugger now supports the following commands The tvariable variable name expression command can be used to define or modify a trace state variable The info tvariables command can be used to display a list of currently defined trace state variables and their values The delete tvariable variable name command can be used to delete one or more trace state variables A new ftrace has been added This command accepts a function name a line number or an address as an argument and can be used to
126. threads access the same memory location concurrently The atomicity is limited to a single read or write access or one of the other atomic operations supported by such types for example two subsequent operations executed on a variable of atomic type are each atomic separately but do not form one joint atomic operation An atomic type is declared as atomic lt T gt where T is the non atomic base type and must be trivially copyable for example atomic lt int gt is an atomic integer GCC does not yet support any base type T but only those that can be accessed atomically with the atomic instructions offered by the target architecture This is not a significant limitation in practice given that atomics are primarily designed to expose hardware primitives in an architecture independent fashion pointers and integrals that are not larger than a machine word on the target are supported as base types Using base types that are not yet supported results in link time errors The code generated for operations on atomic types including the memory orders implements the semantics specified in the C 11 standard However support for the C 11 memory model is still experimental and for example GCC might not always preserve data race freedom when optimizing code GCC also supports new built ins for atomic memory accesses which follow the design of the memory model and new atomic operations The former set of synchronization built ins that is those prefixed
127. tiation Code that incorrectly depends on a second unqualified lookup at the point of instantiation such as finding functions declared after the template or in dependent bases will result in compile time errors In some cases the diagnostics provided by G include hints how to fix the bugs Consider the following code template lt typename T int t T i return f i j int f int i return i j int main return t 1 j The following diagnostics output will be produced 74 Changes in Version 1 0 In instantiation of int t T with T int required from here error f was not declared in this scope and no declarations were found by argument dependent lookup at the point of instantiation fpermissive note int f int declared here later in the translation unit To correct the error in this example move the declaration of function f before the definition of template function t The fpermissive compiler flag turns compile time errors into warnings and can be used as a temporary workaround Uninitialized const Consider the following declaration struct A int a A struct B public A Y const B b An attempt to compile this code now fails with the following error error uninitialized const b fpermissive note const struct B has no user provided default constructor This happens because B does not have a user provided default constructor Either an initializer needs to
128. updated to record more information about each symbol GDB now provides Ada support for GDB MI Variable Objects GDB now supports breakpoint always inserted mode inthe record target gdbserver now supports evaluation of breakpoint conditions Note that you can instruct GDB to send the breakpoint conditions in bytecode form but gdbserver only reports the breakpoint trigger to GDB when its condition evaluates to true The z0 z1 breakpoint insertion packets have been extended to carry a list of conditional expressions over to the remote stub depending on the condition evaluation mode You can use the set remote conditional breakpoints packet command to control the use of this extension A new RSP packet QProgramSignals can be used to specify the signals the remote stub can pass to the debugged program without GDB involvement A new command info os has been added as the MI equivalent of info os Output logs such as set logging and related now include MI output New set use deprecated index sections on off and show use deprecated index sections on off commands have been added These commands allow you to control the use of deprecated gdb index sections New catch load and catch unload commands have been added These commands allow you to stop execution of a debugged program when a shared library is loaded or unloaded A new command enable count has been added This command allows you to auto disable a breakpoint after several hits A new c
129. vtoolset 1 1 gcc debuginfo you can install them at any time by using the following command as root debuginfo install package name 1 7 Uninstalling Red Hat Developer Toolset To uninstall Red Hat Developer Toolset packages from your system type the following at a shell prompt as root yum remove devtoolset 1 1 This removes the GNU Compiler Collection GNU Debugger binutils and other packages that are part of Red Hat Developer Toolset from the system To uninstall the sc1 utility as well type as root yum remove scl utils Note that uninstallation of the tools provided by Red Hat Developer Toolset does not affect the Red Hat Enterprise Linux system versions of these tools 18 Chapter 1 Red Hat Developer Toolset 1 8 Additional Resources For more information about Red Hat Developer Toolset and Red Hat Enterprise Linux refer to the resources listed below Online Documentation provides more information on the Eclipse IDE libraries and runtime support compiling and building debugging and profiling on this system Red Hat Enterprise Linux 6 Installation Guide The Installation Guide for Red Hat Enterprise Linux 6 explains how to obtain install and update the system Linux 6 documents relevant information regarding the deployment configuration and administration of Red Hat Enterprise Linux 6 Linux 5 documents relevant information regarding the deployment configuration and administration of Red Hat Ent
130. w supports using more than 65536 program headers in a file A new function elf getphdrnum has been added eu addr2line now accepts the j section name option in the interests of binutils compatibility libcpu Intel SSE4 disassembler support has been added eu readelf now implements call frame information and exception handling dumping The e command line option has been added this is enabled implicitly by a B 5 Changes in Valgrind 3 8 1 Red Hat Developer Toolset 1 1 is distributed with Valgrind 3 8 1 which provides a number of bug fixes and feature enhancements over the Red Hat Enterprise Linux system version Below is a comprehensive list of new features in this release Changes Since Red Hat Enterprise Linux 6 3 The following features have been added since the release of Valgrind included in Red Hat Enterprise Linux 6 3 Support for Intel Advanced Vector Extensions AVX and Advanced Encryption Standard AES instruction sets has been added Note that this support is only available for 64 bit code A new command line option soname synonyms has been added This option can be used to inform Memcheck Massif Helgrind and DRD that is the tools that replace the malloc function that the implementation of malloc is either linked statically into the executable or is provided by a shared library other than Libc so As a result users can now process both statically linked programs and programs that use other malloc libraries suc
131. will begin with opt Alternatively you can use the following command to confirm that the version number matches that for Red Hat Developer Toolset gcc gcc v During its startup Eclipse prompts you to select a workspace that is a directory in which you want to Red Hat Developer Toolset 1 x User Guide 57 store your projects Either use workspace which is the default option or click the Browse button to browse your file system and select a custom directory You can also select the Use this as the default and do not ask again check box to prevent Eclipse from prompting you the next time you run it When you are done click the OK button to confirm the selection and proceed with the startup 10 3 Additional Resources A detailed description of Eclipse and all its features is beyond the scope of this book For more information refer to the resources listed below Installed Documentation Eclipse includes a built in Help system which provides extensive documentation for each integrated feature and tool This greatly decreases the initial time investment required for new developers to become fluent in its use The use of this Help section is detailed in the Red Hat Enterprise Linux Developer Guide linked below Online Documentation provides more information on Eclipse including a description of the user interface overview of available development toolkits or instructions on how to use it to build RPM pack
132. y large local arrays may require you to extend your runtime limits for stack memory Compile time has been significantly improved For example the improvement may be noticeable when working with programs that use large array constructors To improve code generation and diagnostics the fwhole file compile flag is now enabled by default and can be used with a newly supported fwhole program flag To disable it use the deprecated fno whole file flag A new command line option M is now supported Similarly to gcc this option allows you to generate Makefile dependencies Note that the cpp option may be required as well The finit real command line option now supports snan as a valid value This allows you to initialize REAL and COMPLEX variables with a signaling NaN not a number and requires you to enable trapping for example by using the f fpe trap command line option Note that compile time optimizations may turn a signaling NaN into a quiet NaN A new command line option fcheckz has been added This option accepts the following arguments The fcheck bounds option is equivalent to the fbounds check command line option The fcheck array temps option is equivalent to the fcheck array temporaries command line option The fcheckzdo option checks for invalid modification of loop iteration variables The fcheck recursive option checks for recursive calls to subroutines or functions that are not marked as recursive The fcheck point
133. you start the execution gdb displays the lines that are surrounding the line on which the execution stops typically when you set a breakpoint You can also display the code that is surrounding a particular line To do so run the command in the following form list file name line number Similarly to display the code that is surrounding the beginning of a particular function run list file name function name Note that you can change the number of lines the list command displays by running the following command set listsize number Example 3 4 Listing the Source Code of the fibonacci Binary File has exactly 17 lines Assuming that you have compiled it with debugging information and you want the gdb utility to be capable of listing the entire source code you can run the following command to change the number of listed lines to 20 gdb set listsize 20 You can now display the entire source code of the file you are debugging by running the list command with no additional arguments gdb list 1 amp include stdio h 2 include lt limits h gt 3 4 int main int argc char argv 5 unsigned long int a 0 6 unsigned long int b 1 7 unsigned long int sum 8 9 while b lt LONG_MAX 10 printf ld b 11 sum a b 12 a b 18 b sum 14 15 16 return 0 32 Chapter 3 GNU Debugger GDB Setting a New Breakpoint To set a new breakpoint at a certain line run the following command
134. ype pseudo operation This value can be used to mark a symbol as globally unique in the entire process Support for the new discriminator column in the DWARF line table with a discriminator operand for the loc directive has been added The type pseudo operation now accepts a type of STT GNU IFUNC This can be used to indicate that if the symbol is the target of a relocation its value should not be used Instead the function should be invoked and its result used as the value A new pseudo operation cfi val encoded addr has been added This pseudo operation can be used to record constant addresses in unwind tables without runtime relocation A new command line option msse check none error warning has been added for x86 targets The a command line option now accepts g as a valid sub option This combination can be used to enable assembly listings with additional information about the assembly including the list of supplied command line options or the assembler version A new command line option msse2avx has been added for x86 targets This option can be used to encode SSE instructions with VEX prefix x86 targets now support the Intel XSAVE EPT MOVBE AES PCLMUL and AVX FMA instructions New command line options march cpu extension mtune cpu mmnemonic att intel msyntax att intel mindex reg mnaked reg and mold gcc have been added for x86 targets New pseudo operations string16 string32 and str

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