LI74773: -QDATALOCAL CAUSES UNEXPECTED OUTPUT

June 2009 Update for XL C/C++ Advanced Edition for Linux, V9.0
February 2010 Update for XL C/C++ Advanced Edition for Linux, V9.0
February 2011 Update for XL C/C++ Advanced Edition for Linux, V9.0

APAR status

• Closed as program error.

Error description

• Compiling the following test case with -qdatalocal causes
  unexpected output.
  
  =====
  /* filename: main.c */
  int main() { func(); }
  =====
  /* filename: func.c */
  extern long *YYY;
  void  func(void) { printf("*YYY = %d\n", *YYY); }
  static void func1(void) {
     void **  fp;
     __asm ("ori %0, 1, 0" : "=r" (*(fp)));
  }
  =====
  /* filename: data.c */
  long     XXX = 9999;
  long    *YYY = &XXX;
  =====
  
  $ xlc -q64 data.c func.c main.c -qdatalocal && ./a.out
  data.c:
  func.c:
  main.c:
  *YYY = 224384
  

Local fix

• N/A
  

Problem summary

• Users of inline asm are affected by this issue.
  
  The issue was that accessing TOC direct data defined in another
  compilation unit was not working. So the compiler wasn't
  generating the correct assembly for it.
  

Problem conclusion

• This has been fixed.
  

Temporary fix

Comments

APAR Information

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

  IZ47265

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

Fix information

• Fixed component name

  XL C/C++ RHEL5

• Fixed component ID

  5724S7310

Applicable component levels

• R900 PSN IZ47265

     UP06/09/13