PI50508: INCORRECT CODE GEN WHEN USING __ATTRIBUTE__((AMODE31)) WITH LP64

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When compiling with V2R1 and LP64, the following test case shows
  how the compmiler generates incorrect code gen when using
  __attribute__((amode31)):
  
  
  ===== COMPILE COMMAND:
  xlc -Wc,"METAL,LONG,LP64" -S test.c -I/usr/include/metal
  
  
  ===== TESTCASE:
  $ cat test.c
  #include <metal.h>
  #include <stdlib.h>
  #include <string.h>
  #include <stdio.h>
  #include <stdarg.h>
  #include <ctype.h>
  
  
  
  typedef int(* __ptr32 a31)(char *, ...)
  __attribute__((amode31));
  
  int main(int argc, char **argv)
  {
  
    a31 * __ptr32 a31_ptr = 0;
    char c1[32];
    char c2[32];
    int j = (*a31_ptr)(c1,c2);
  
  }
  $
  
  
  The relevant source lines are:
  typedef int(* __ptr32 a31)(char *, ...)
  __attribute__((amode31));
  which defines the function as a 31 bit function
  
  then the call to the function:
  int j = (*a31_ptr)(c1,c2);
  which should result in the generation of 31 bit pointers in the
  call sequence.
  
  
  ===== ACTUAL LISTING OUTPUT:
  SAM31
  LA    1,152(,13)
  ST    2,152(,13)
  ST    0,156(,13)
  ST    2,160(,13)
  ST    14,164(,13)
  MVC   8(4,13),#NAB_1+4
  BASR  14,15
  LGR   15,2
  SAM64
  
  ===== EXPECTED LISTING OUTPUT:
  SAM31
  LA    1,152(,13)
  ST    0,152(,13)
  ST    14,156(,13)
  MVC   8(4,13),#NAB_1+4
  BASR  14,15
  LGR   15,2
  SAM64
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: zOS METALC programmers who use mixed mode    *
  *                 functions without explicit AMODE qualifiers. *
  ****************************************************************
  * PROBLEM DESCRIPTION: When compiling a METALC program         *
  *                      containing mixed mode functions the     *
  *                      compiler does not emit correct          *
  *                      assembler instructions for invoking     *
  *                      mixed mode functions using a function   *
  *                      pointer.                                *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  

Problem conclusion

• Apply provided service.
  

Temporary fix

Comments

APAR Information

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

  PI37313

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

Modules/Macros

•    CCNEP
  

Fix information

• Fixed component name

  C/C++ FOR MVS

• Fixed component ID

  56551210A

Applicable component levels

• R791 PSY UI32071

     UP15/11/21 P F511

Fix is available

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