Tool Development and Support SPARK Toolset Release Note
Contents
1. expression evaluation e variable initialization at declaration e full range scalar subtypes and e operator renaming in package specifications 13 2 Release 2 1 July 1996 Release 2 1 added e facilities for proof of absence of run time errors 13 3 Release 2 5 March 1997 Release 2 5 was distributed with High Integrity Ada the SPARK Approach and provided initial facilities for SPARK 95 13 4 Release 3 0 September 1997 Windows NT was supported for the first time with this release Release 3 0 also added e additional SPARK 95 support e flow analysis of record fields e command line meta files e named numbers e unqualified string literals e moded global annotations and Page 20 of 28 Dj y TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 e optional information flow analysis 13 5 Release 4 0 December 1998 With Release 4 0 we upgraded all users to a single product standard supporting SPARK 83 SPARK 95 and analysis options up to an including proof facilities New features were e full implementation of public and private child packages e default switch file and e provision of the INFORMED design document 13 6 Release 5 0 June 2000 e Enhanced proof support I facilities for proof of programs containing abstract state ll addition of quantified expressions lll proof rule generation for enumeration types IV identification of2. the kind and source of each VC V suppression of trivially true VCs VI Proof Obligation Summariser tool POGS e Optional HTML output files with hyperlinks that can be browsed interactively e Better support for common Ada file naming conventions e User selectable annotation character e Improved suppression of analysis were results might otherwise be misleading e Static expression evaluation in proof contexts e Singleton enumeration types e Revised SPARK_IO package e Error numbering Page 21 of 28 os Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 M 13 7 Release 6 0 November 2001 e Introduction of external variables to simplify modelling of the interactions between a SPARK program and its external environment e Addition of the null derives annotation to describe information flows which affect only the external environment e introduction of modular types e Use of loop labels in exit statements e Use of global modes on function subprograms e Extended support for predefined types such as Long_Integer e Simplified run time check generation for own variables e Relaxation of need for mandatory type announcement of own variables e Plain output option to simplify comparisons of Examiner output files e Platform independent switch files and metafiles e Support for intentionally infinite loops e Detection of own variables that can never be initiali
3. ctually not True This has been corrected in release 2 24 If a project is using Simplifier 2 22 and userdefined proof rules rlu files then we recommend that proofs should be re generated and checked Page 10 of 28 Dj y TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 6 SPADE Proof Checker SPADE Proof Checker version 2 07 ships with toolset release 7 31 This includes a single improvement over and above version 2 06 6 1 Correction to side conditions in ARITH RUL Two rules intdiv 5 and intdiv 6 have been corrected so that their side conditions can be successfully evaluated In prior versions of the Checker these rules were unusable Page 11 of 28 a Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 M 7 POGS No change between releases 7 3 and 7 31 Page 12 of 28 a Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 M 8 SPARKFormat No change between releases 7 3 and 7 31 Page 13 of 28 a Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 M 9 SPARKMake No change between releases 7 3 and 7 31 Page 14 of 28 os Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 M 10 Backward incompatibilities There are no known backward incompatibilities introduced betwe
4. eka Tool Development and Support SPARK Toolset Release Note Release 7 31 EXM RN Issue 1 1 Status Definitive 13 April 2006 Originator SPARK Team Approver SPARK Team Line Manager ss Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 M Copyright The contents of this manual are the subject of copyright and all rights in it are reserved The manual may not be copied in whole or in part without the written consent of Praxis High Integrity Systems Limited The software tools referred to in this manual are the subject of copyright and all rights in them are reserved The rights in these tools are owned by Praxis High Integrity Systems Limited and it may not be copied in whole or in part without the written consent of this company except for reasonable back up purposes The same proprietary and copyright notices must be affixed to any permitted copies as were affixed to the original This exception does not allow copies to be made for others whether or not sold and none of the material purchased may be sold given or loaned to another person or organisation Under law copying includes translating into another language or format 1991 2006 Praxis High Integrity Systems Limited 20 Manvers St Bath BA1 1PX Limited Warranty Praxis High Integrity Systems Limited save as required by law makes no warranty or representation either express or implied with respect to this s
5. emented by the Examiner The Examiner will generate error number 30 Attribute XXX is not yet implemented in the Examiner if you try to use them e Adjacent e Compose e Copy_Sign e Leading_Part e Remainder e Scaling e Exponent Fraction Machine Model e Rounding e Truncation Unbiased_Rounding Note that these are all function like attributes concerning floating and fixed point types 12 1 3 2 Unevaluable attributes The Machine_ and Model_ attributes are accepted by the Examiner but it does not know how to statically evaluate them since they are inherently implementation dependent For example the package package F is type T is digits 6 range 10 0 10 0 Page 18 of 28 Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 C constant T Machine_Emax end F is legal SPARK but the Examiner does not know the actual numeric value of C 12 2 Known error summary This section lists known errors in the Examiner that are awaiting investigation and correction 1 The SPARK rule that array actual parameters must have the same bounds as the formal parameter is not checked for function parameters where the actual parameter is a subtype of an unconstrained array type Since subtype bounds are static in SPARK errors of this kind should be detected by an Ada compiler If not an unconditional run time error will occur SEPR 1060 The Examiner
6. en Examiner Releases 7 3 and 7 31 Page 15 of 28 a TH Tool Development and Support SPARK Toolset Release Note Release 7 31 11 User manual change summary No changes other than the addition of this release note and 11 1 Checker Rules e Correction to rules in ARITH RUL as described in section 6 1 above 11 2 Examiner User Manual e Version number updated to 7 31 11 3 Simplifier User Manual e Documentation of typecheck option EXM RN Issue 1 1 Page 16 of 28 M oss Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 12 Limitations and known errors 12 1 Tool limitations This section describes limitations of the Examiner tool arising mainly from incomplete implementation of planned features Where appropriate a SPARK Examiner Performance Report SEPR number is given 12 1 1 General The SPARK 95 language definition removes the distinction between initial and later declarative items this distinction remains in force in the Examiner that requires SPARK 83 declaration orders even in SPARK 95 mode SEPR 813 The Examiner does not yet permit the use of 8 bit characters in SPARK 95 userdefined identifiers SEPR 818 Universal expressions in a modular context may sometimes require type qualification SEPR 1591 The Examiner does not yet permit the use of use type following an embedded package specification SEPR 747 The Examiner does not yet permit
7. file tables have been increased in the Large and Mega variants of the Examiner for release 7 31 Page 9 of 28 a Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 M 5 SPADE Simplifier Simplifier 2 24 ships with toolset release 7 31 This incorporates the following improvements and features 5 1 Port to Mac PowerPC OS X The FreeDemo version of the Simplifier that accompanies the SPARK Book is now available for the Apple Mac PowerPC OS X operating system 5 2 New typecheck option A new command line option typecheck is now available This instructs the Simplifier to read in and type check the input files e g VCG FDL and RLS files but to perform no further simplification No output files are produced This option is useful to quickly scan a large set of VCG files for legality before committing to a full simplification attempt when used in conjunction with the SPARKSimp tool For example to scan a full directory tree of VCG files for type correctness on Windows sparksimp a l sargs typecheck Or on UNIX platforms sparksimp a 1 sargs typecheck More details in the Simplifier User Manual section 5 1 5 3 Stricter checking of user defined proof rules Simplifier 2 22 could sometimes allow a user defined proof rule to be applied incorrectly In some circumstances this could lead to simplifier mistakenly proving a VC that was a
8. includes variables or imported parameters AND e The formal parameter is mode out In this case the computed flow relation incorrectly excludes the variables used in the index expression SPARK Examiner releases affected by this defect are 7 1 7 2 and 7 3 Examiners prior to release 7 1 are not affected since passing array elements as parameters was not allowed at all Example Given type Index is range 1 10 type A is array Index of T procedure Clear X out T derives X from Ss A and procedure Clear_Elem E in Index global in out S derives S from S E correct is begin Clear S E end Clear_Elem Examiner 7 3 incorrectly reports Page 8 of 28 TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 Flow Error 30 The variable E is imported but neither referenced nor exported Flow Error 50 S is not derived from the imported value s of E This analysis is corrected in Examiner release 7 31 Recommendation Projects using Examiners 7 1 7 2 or 7 3 should upgrade to release 7 31 as soon as possible A back to back analysis of programs should be performed to detect any instances of this problem Code that is normally analysed with Examiners 7 0 or earlier cannot be affected by this problem 4 2 Examiner table sizes The maximum sizes of the compilation unit and source
9. ire a full professional SPARK toolset for Linux then please contact us 14 5 Apple PowerPC OS X All the toolset with the exception of the Checker is compatible with Apple s PowerPC OS X Darwin operating systems Only the FreeDemo version of the toolset is currently available for OS X to support buyers of John Barnes SPARK Book If you require a full professional SPARK toolset for OS X then please contact us Page 27 of 28 Dj y TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 Document Control and References Praxis High Integrity Systems Limited 20 Manvers Street Bath BA1 1PX UK Copyright Praxis High Integrity Systems Limited 2006 All rights reserved Changes history Issue 0 1 30th March 2006 First draft for release 7 31 Issue 1 0 30th March 2006 Definitive issue following review Issue 1 1 13th April 2006 Addition of Simplifier 2 24 Changes forecast Updates following review Document references File under CVSROOT userdocs Examiner_RN_7p31 doc Page 28 of 28
10. mat tool Release 7 2 December 2004 Release 7 2 of the toolset comprised Examiner version 7 2 Simplifier version 2 17 Page 24 of 28 M 13 12 Tool Development and Support Release 7 2 added e Unconstrained string constants to the language e instantiation of Unchecked_Conversion to the language e Full record subtypes to the language e Declaration of subprograms in the private part of packages e Refined proof annotations for private types e suffix for referring to value of variable on entry to loop in proof contexts e Extra hypotheses for local variables e Suppression of VC generation for illegal function bodies e Replacement rules for composite constants e Concurrent simplification with SPARKSimp e Improved simplification of VCs with large structured objects e Improved simplification of arithmetic and logical expressions e New SPARKMake tool Release 7 3 February 2006 Release 7 3 of the toolset comprised Examiner version 7 3 Simplifier 2 22 Checker 2 06 Significant features of this release included e Improved VC Generation e New error explanations switch for Examiner e Generation of proof rules for Size e Improved diagnosis and reporting of common syntax errors SPARK Toolset Release Note Release 7 31 EXM RN Issue 1 1 Page 25 of 28 TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 e Err
11. oftware its quality performance merchantability or fitness for a purpose As a result the licence to use this software is sold as is and you the purchaser are assuming the entire risk as to its quality and performance Praxis High Integrity Systems Limited accepts no liability for direct indirect special or consequential damages nor any other legal liability whatsoever and howsoever arising resulting from any defect in the software or its documentation even if advised of the possibility of such damages In particular Praxis High Integrity Systems Limited accepts no liability for any programs or data stored or processed using Praxis High Integrity Systems Limited products including the costs of recovering such programs or data SPADE is a trademark of Praxis High Integrity Systems Limited Note The SPARK programming language is not sponsored by or affiliated with SPARC International Inc and is not based on SPARC architecture Page 2 of 28 TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 Contents 1 Introduction 5 2 Contact Information 6 3 SPARK language changes 7 4 Examiner changes 8 4 1 Correction to flow analysis of array element parameters SEPR 1962 8 4 2 Examiner table sizes 9 5 SPADE Simplifier 10 5 1 Port to Mac PowerPC OS X 10 5 2 New typecheck option 10 5 3 Stricter checking of userdefined proof rules 10 6 SPADE Proof Checker 11 6 1 Correction to side condi
12. or and warning count summary in Examiner output e Use of pragma Import to complete an external own variable e Correction to FDL declaration order for private and announced types e New Simplifier tactics for dealing with rational inequalities and Examiner generated proof rules e User defined proof rules for the Simplifier e New Checker rules for MODULAR expressions e Significant performance improvement for Simplifier and Checker Page 26 of 28 os Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 M 14 Operating system compatibility 14 1 VAX VMS Examiner 7 31 is available for VAX VMS releases 5 5 2 and above The other tools are not available for VAX VMS at this time 14 2 SPARC Solaris The toolset is compatible with Solaris 5 6 through to 10 including those with a 64 bit kernel 14 3 Windows NT 2000 and XP The toolset is compatible with Windows NT 4 0 Windows 2000 and Windows XP The executables are also known to work on Windows 95 and 98 however use of the toolset on these operating systems is unsupported The FlexLM licence manager software only runs on Windows NT Windows 2000 or Windows XP 14 4 Intel Linux All the toolset with the exception of the Checker is compatible with Intel based Linux operating systems Only the FreeDemo version of the toolset is currently available for Linux to support buyers of John Barnes SPARK Book If you requ
13. permits the body of a subprogram to be entirely made up of proof statements thus breaching the Ada rule that at least one Ada statement must be present SEPR 278 Where a package declares two or more private types the Examiner permits mutual recursion between their definitions in the private part of the package SEPR 848 The Examiner does not take due account of a range constraint when determining the subtype of a loop variable this affects completeness checking of case statements within the loop For example for I in Integer range 1 4 loop would require only values 1 2 3 and 4 to be covered by the case statement SEPR 693 When summarising the counts of pragmas found during an analysis the totals may depend on whether units are selected via the command line or metafile or using the index mechanism The difference affects only pragmas placed between program units and arises because placing a file name on the command line causes the entire file to be analysed whereas selecting it using indexes causes only the required unit to be read from the file SEPR 483 Page 19 of 28 Dj y TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 13 Change Summary from Release 2 0 A release note detailing changes from the previous version accompanies each Examiner Release this section simply summarises the various changes that have been made 13 1 Release 2 0 November 1995 Release 2 0 added e static
14. the renaming of packages in the same way that subprograms can be renamed SEPR 1391 The Examiner does not yet allow the Base attribute when not used as a prefix SEPR 1114 The Examiner does not yet allow S Range where S is scalar SEPR 1115 12 1 2 Verification Condition Generation and Run time Checks 1 2 Ada string inequality is not modelled SEPR 712 VCs involving string catenation that includes the character ASCII NUL will be incorrect SEPR 661 Aggregates of multi dimensional arrays cannot be modelled although aggregates of arrays of arrays can SEPR 590 Verification conditions involving real numbers are evaluated using infinite precision or perfect arithmetic this allows the correctness of an algorithm to be shown but cannot guard against the effects of cumulative rounding errors for example The Examiner does not generate VCs for package initialization parts Statically determinable constraint errors will be detected during well formation checking of package initialization SEPR 288 Page 17 of 28 Dj y TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 6 The VC Generator cannot model the implementation dependent attributes of floating and fixed point types see section 12 1 3 12 1 3 Attribute limitations 12 1 3 1 Unimplemented attributes The following attributes are officially supported by SPARK according to the language definition but are not yet impl
15. tions in ARITH RUL 11 7 POGS 12 8 SPARKFormat 13 9 SPARKMake 14 10 Backward incompatibilities 15 11 User manual change summary 16 11 1 Checker Rules 16 11 2 Examiner User Manual 16 11 3 Simplifier User Manual 16 12 Limitations and known errors 17 12 1 Tool limitations 17 12 2 Known error summary 19 13 Change Summary from Release 2 0 20 13 1 Release 2 0 November 1995 20 13 2 Release 2 1 July 1996 20 13 3 Release 2 5 March 1997 20 13 4 Release 3 0 September 1997 20 13 5 Release 4 0 December 1998 21 13 6 Release 5 0 June 2000 21 13 7 Release 6 0 November 2001 22 13 8 Release 6 1 June 2002 22 13 9 Release 6 3 December 2002 24 13 10 Release 7 0 July 2003 24 13 11 Release 7 2 December 2004 24 Page 3 of 28 TH Tool Development and Support SPARK Toolset Release Note Release 7 31 13 12 Release 7 3 February 2006 14 Operating system compatibility 14 1 VAX VMS 14 2 SPARC Solaris 14 3 Windows NT 2000 and XP 14 4 Intel Linux 14 5 Apple PowerPC OS X Document Control and References Changes history Changes forecast Document references File under EXM RN Issue 1 1 Page 4 of 28 a Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 1 introduction Release 7 3 of the SPARK toolset was made available to users in February 2006 Subsequently a defect was discovered in the Examiner s flow analyser that necessitates a release 7 31 to correct this issue A n
16. ualities e Simplification of VCs involving quantified expressions e Simplifier performance e Checker has new built in rule families MODU LAR BITWISE and ENUMERATION e Proved by review option in POGS Page 23 of 28 M oss Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 13 9 Release 6 3 December 2002 13 10 13 11 Release 6 3 of the toolset was constructed to accompany the textbook High Integrity Software The SPARK Approach to Safety and Security by John Barnes but was not delivered to other users Its main new features were Slight revision to the rules regarding the placement of tagged type declarations Correction to the modelling of Boolean type membership operators in the verification conditions Support for generating VCs that allow the verification of the Liskov Subsitution Principal LSP for tagged types and their operations Dramatically improved performance of the Simplifier particularly in the simplification of quantified expressions Release 7 0 July 2003 Release 7 0 of the toolset comprised Examiner version 7 0 Simplifier version 2 12 Release 7 0 added Ravenscar profile extensions to the language Support for Ada lnterrupts and Ada Real_Time in the configuration file The new noduration command line switch VC generation for unconstrained formal parameters Suppression of VC generation for illegal function bodies New SPARKFor
17. umber of other small improvements have also been made to the Simplifier and Checker This document describes changes in the behaviour of all variants of the SPARK Toolset Release 7 31 compared to Release 7 3 Page 5 of 28 Dj y TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 2 Contact Information For further information about this document please contact Praxis High Integrity Systems By phone 44 0 1225 823829 direct line 44 0 1225 466991 exchange By FAX 44 0 1225 469006 By email sparkinfo praxis his com Page 6 of 28 Dj y TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 3 SPARK language changes None Page 7 of 28 a Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 M 4 Examiner changes This section documents other significant changes to the SPARK Examiner made for release 7 31 Where appropriate SPARK Examiner Performance Report SEPR numbers are given 4 1 Correction to flow analysis of array element parameters SEPR 1962 Release 7 1 of the SPARK language and Examiner introduced a rule that allows array elements to be passed to formal procedure parameters of mode in out or out Subsequent analysis has shown that information flow analysis is not correct in the following case e The index of the array element passed is selected by an expression which
18. zed e Detection of unusable private types e Extra refinement checks on global variables when performing data flow analysis e Detection of unnecessary others clause in case statements e Extensions to the POGS tool e Improved error messages to distinguish different cases of variables which are not declared or visible e Improved SPADE Simplifier Release 2 0 e New SPARKSimp Tool 13 8 Release 6 1 June 2002 e Introduction of tagged types Page 22 of 28 TH Tool Development and Support EXM RN SPARK Toolset Release Note Release 7 31 Issue 1 1 e Introduction of type assertion annotations e Introduction of modular subtypes e Introduction of the configuration file e Introduction of the help command line switch e Demo Examiner now runs on Linux e VCG generation for inherited operations of tagged types e Improved handling of null derives e Attributes Floor and Ceiling implemented e Detection of duplicate record fields e Improved overflow checks on universal integer expressions e Corrected handling of loop invariants in while loops e Strengthened behaviour of noecho option e Trapping non positive accuracy in real type declaration e Recursion in meta files and index files e Improved handling of Address clauses e Improved handling of Import and Interface pragmas e VCG Modelling of Boolean membership operators e Simplification of common Integer inequalities e Simplification of common enumerated ineq
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