IJ06432: GLOBAL DESIGNATED INITIALIZER USING COMPOUND LITERAL FAILING WITH EXTC99

XL C for AIX, V13.1.3.5 Fix Pack (July 2018)
XL C/C++ for AIX, V13.1.3.5 Fix Pack (July 2018)
XL C/C++ for AIX Fix Pack 11 (November 2018 PTF) for 13.1
XL C for AIX Fix Pack 11 (November 2018) for 13.1
XL C for AIX, V13.1.3.6 Fix Pack (May 2019)
XL C/C++ for AIX, V13.1.3.6 Fix Pack (May 2019)

APAR status

• Closed as program error.

Error description

• When compiling with the -qlanglvl=extc99 language level, the
  compiler is outputting invalid warning messages for a global
  designated initializer usage.  The initializer uses a compound
  literal.  The compile succeeds, but encounters a segmentation
  fault at runtime related to accessing the compound literal.
  
  
     === TEST CASE ===
  
  #include <stdio.h>
  
  struct s {
          char **c;
  };
  
  struct s st= {  .c = (char *[]){"this","that",0}  };
  
  int main(int argc,char *argv[])
  {
          printf("%s %s\n",st.c[0],st.c[1]);
          return 0;
  }
  
  
  $ xlc apar.c -qlanglvl=extc99
  "apar.c", line 7.33: 1506-196 (W) Initialization between types
  "char**" and "char*" is not allowed.
  "apar.c", line 7.40: 1506-026 (W) Number of initializers cannot
  be greater than the number of aggregate members.
  "apar.c", line 7.47: 1506-026 (W) Number of initializers cannot
  be greater than the number of aggregate members.
  $
  $ ./a.out
  Segmentation fault (core dumped)
  $
  

Local fix

• Compiling with -qlanglvl=stdc99 works.
  

Problem summary

• PROBLEM DESCRIPTION:
  C code containing array compound literals as initializers at
  global scope could experience run-time crashes when compiled in
  extended mode.
  
  USERS AFFECTED:
  Users of XL C compilers with code containing compound literals
  as initializers at global scope in extended mode.
  

Problem conclusion

• A fix was applied to avoid generating incorrect code for
  initializing global variables using compound literals with
  array type.
  

Temporary fix

Comments

APAR Information

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

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

  IJ08179

Fix information

• Fixed component name

  XL C FOR AIX

• Fixed component ID

  5725C7100

Applicable component levels

• RD10 PSY

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