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LI76227: EXTERN TLS VARIABLE CAUSING ASSEMBLER ERROR

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APAR status

  • Closed as program error.

Error description

  • The following test case is generating invalid assembly syntax
    which the assembler does not understand.  The issue is related
    to how thread local storage variables are set to 'extern'.
    
    
      ===== TESTCASE =====
    extern __thread int x, *p;
    
    int  mytest(void **fp)
    {
      __asm ("ori %0, 1, 0" : "=r" (*(&fp)));
      p = &x;
    
            return 6;
    }
    
    This generates the following assembly:
    
    --------------------------------------------
      +106          .tc     x[TC],x[UL]
      +115          .extern x[UA]
    --------------------------------------------
    
    Which causes these assembly errors:
    
    --------------------------------------------
    Assembler:
    tls.s: line 106: 1252-023 The symbol x is not defined.
    tls.s: line 106: 1252-040 The specified expression is not valid.
            Make sure that all symbols are defined.
            Check the rules on symbols used in an arithmetic
            expression concerning relocation.
    --------------------------------------------
    
    OR
    
    --------------------------------------------
    Assembler:
    tls.s: line 106: 1252-142 Syntax error.
    --------------------------------------------
    
    The correct syntax should look like:
    
    --------------------------------------------
      +106          .tc     x[TC],x[UL]
      +115          .extern x[UL]
    --------------------------------------------
    

Local fix

  • Remove 'extern' from TLS variable.
    

Problem summary

  • PROBLEM DESCRIPTION:
    extern thread local variables do not work when inline ASM is
    present.
    
    USERS AFFECTED:
    Users with TLS programs that want to use inline ASM.
    

Problem conclusion

  • The issue was corrected.
    

Temporary fix

Comments

APAR Information

  • APAR number

    LI76227

  • Reported component name

    XL C/C++ SLES10

  • Reported component ID

    5724U8300

  • Reported release

    A10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-06-10

  • Closed date

    2011-06-10

  • Last modified date

    2011-06-10

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

    IZ93006

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

Fix information

  • Fixed component name

    XL C/C++ SLES10

  • Fixed component ID

    5724U8300

Applicable component levels



Document information

More support for: XL C/C++

Software version: A.1

Reference #: LI76227

Modified date: 10 June 2011