PM80361: COBOL R/T ENHANCEMENT FOR DEBUGGING

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• Enhancement to COBOL runtime to support Debug Tool.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of IBM Debug Tool with COBOL programs  *
  *                 compiled with OPTIMIZE and either the        *
  *                 TEST(NONE) or TEST(NOHOOK,NOEJPD) options    *
  *                 who would like to use the GOTO or JUMPTO     *
  *                 Debug Tool commands.                         *
  *                                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: When debugging programs compiled with   *
  *                      the OPTIMIZE option and either the      *
  *                      TEST(NONE) or the TEST(NOHOOK,NOEJPD)   *
  *                      option, the JUMPTO and GOTO commands    *
  *                      are not enabled from the Debug Tool     *
  *                      command line.                           *
  *                                                              *
  *                      JUMPTO and GOTO are not supported in    *
  *                      this case. The potential exists for     *
  *                      entering statements with the wrong      *
  *                      register values which could lead to     *
  *                      incorrect data being used, unexpected   *
  *                      paths being taken or abends.            *
  *                                                              *
  *                      The TEST(EJPD) option was introduced    *
  *                      in COBOL V4R1 to allow GOTO and         *
  *                      JUMPTO commands under the Debug Tool    *
  *                      with a reduced risk of unexpected       *
  *                      behavior when debugging an OPTIMIZE     *
  *                      compile. TEST(EJPD) generates some      *
  *                      additional instructions to ensure that  *
  *                      register values are as expected on      *
  *                      entry.                                  *
  *                                                              *
  *                      Some users still want to be able        *
  *                      use GOTO and JUMPTO commands to debug   *
  *                      OPTIMIZE compiles without TEST(EJPD)    *
  *                      and are willing to risk unexpected      *
  *                      results.                                *
  *                                                              *
  ****************************************************************
  * RECOMMENDATION: Apply the provided PTF.                      *
  *                                                              *
  ****************************************************************
  Users want to be able to use the Debug Tool GOTO and JUMPTO
  commands in OPTIMIZED compiles when the SET WARNING setting is
  OFF, despite the risk of abends or other unexpected results.
  

Problem conclusion

Temporary fix

Comments

• Debug Tool is changed with this update to allow commands GOTO
  and JUMPTO in COBOL programs that are compiled with OPTIMIZE
  and TEST(NOEJPD) or TEST(NONE), as long as SET WARNING OFF is
  also used.
  
  This functionality is provided with a strong warning that users
  may find that GOTO or JUMPTO will cause ABENDS in this
  configuration. Any type of failure when using GOTO or JUMPTO
  with a program compiled using OPT and TEST(NOEJPD) will
  not be reviewed by IBM service.
  
  For example, if a user gets an ABEND on or following a GOTO
  command while debugging a COBOL program that was compiled with
  OPT and TEST(NOEJPD), the user might want to try the same GOTO
  in a program compiled with OPT and TEST(EJPD). IBM Service will
  not investigate failures or ABENDS caused by GOTO or JUMPTO
  commands in COBOL programs compiled with OPT and TEST(NOEJPD).
  
  Without this change, Debug Tool commands GOTO and JUMPTO are
  disabled for COBOL programs that are compiled with OPTIMIZE and
  TEST(NOEJPD) or TEST(NONE), regardless of the  SET WARNING
  setting used.
  
  With this change, users can compile their code for maximum
  performance and use the GOTO and JUMPTO commands when the SET
  WARNING OFF setting is in effect, however the results of using
  the commands may be unpredictable
  
  Users will get the best behavior of GOTO and JUMPTO in programs
  compiled with OPT and TEST(NOEJPD) when the target of the GOTO
  or JUMPTO command is a paragraph name or section name (label),
  or is the first statement in the paragraph or section,
  especially if these procedures are objects of COBOL statements
  PERFORM or GO TO in the COBOL program.
  
  For fully supported (serviceable) GOTO and JUMPTO behavior,
  programs must be compiled with NOOPT and TEST or with OPT and
  TEST(EJPD). (These programs will not run as fast as programs
  compiled with OPT and TEST(NOEJPD). )
  
  Debug Tool update required:
  =====================================
    For Debug Tool V12R1, the PTF for APAR PM75819 must be applied
    to use this function.
  
  COBOL Publications Updates
  =====================================
  
  Enterprise COBOL For z/OS V4R2 Programming Guide SC23-8529-01
  
  In the COBOL Programming Guide Section describing the compiler
  options, the TEST compiler option description will be changed.
  
  After the description of the TEST suboptions, EJPD and NOEJPD,
  add the following text:
  
  
   | Notes regarding EJPD and NOEJPD:
   |  Certain levels of the Debug Tool and Language Environment
   |  runtime will allow the use of the JUMPTO and GOTO commands
   |  in debugging sessions regardless of the setting of the EJPD
   |  option  . When NOEJPD is used the commands are not enabled
   |  by the compiler and may be used only when the Debug Tool
   |  SET WARNING OFF setting is active.
   |
   |  In that case the functionality is provided with a strong
   |  warning that users may find that GOTO or JUMPTO will
   |  cause ABENDS in this configuration. Any type of failure
   |  when using GOTO or JUMPTO with a program compiled using
   |  OPT and TEST(NOEJPD) will not be reviewed by IBM service.
   |
   |  For fully supported (serviceable) GOTO and JUMPTO behavior,
   |  programs must be compiled with NOOPT and TEST or with OPT
   |  and TEST(EJPD) to enable the GOTO and JUMPTO commands.
   |  (These programs will not run as fast as programs compiled
   |  with OPT and TEST(NOEJPD). )
  
  Additionally, in the same section on the TEST option, change
  the text in the paragraphs describing Performance versus
  Debugging Capability to read as follows:
  
      Performance versus debugging capability:
  
      You can control the amount of debugging capability that you
      get and so also the program performance, as follows:
  
      - For the best performance, but with some restrictions on
        debugging, compile using OPTIMIZE and
        TEST(NOHOOK,. . .,NOEJPD).
  
        When you use the Dynamic Debug facility of Debug Tool
        (SET DYNDEBUG ON), you can interactively debug your
        program even if the program has no compiled-in debug
        hooks.
  
        With TEST(NOHOOK,. . .,NOEJPD), you can also compile
        using OPTIMIZE (either OPT(STD) or OPT(FULL)) for a
        more efficient program, but with some restrictions on
        debugging:
   |       - The Debug Tool commands JUMPTO and GOTO are not
             enabled.
           - Except for the DESCRIBE ATTRIBUTES command, Debug
             Tool commands cannot refer to any data item that
             was discarded from a program by the OPT(FULL)
             option.
           - The Debug Tool command AT CALL entry-name is not
             supported.
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UK91517 UK91518 UK91519

Modules/Macros

•    IGZIVGO  IGZIVID
  

Fix information

• Fixed component name

  LE COBOL LIB

• Fixed component ID

  568819802

Applicable component levels

• R760 PSY UK91517

     UP13/02/12 P F302

• R770 PSY UK91518

     UP13/02/12 P F302

• R780 PSY UK91519

     UP13/02/12 P F302

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.