LI76644: UNRESOLVED SYMBOL ERRORS WITH -QIPA

XL C/C++ for Linux Fix Pack 9 (August 2013 Update) for 11.1
June 2012 Update for XL C/C++ for Linux, V11.1
October 2012 Update for XL C/C++ for Linux, V11.1
XL C/C++ for Linux Fix Pack 8 (June 2013 Update) for 11.1

APAR status

• Closed as program error.

Error description

• When compiling the following test case with -qipa, the IPA
  linker complains about type mis-matches when it should not:
  
  ===== TESTCASE:
  $cat main.c
  
  struct A {
    int a,b,c;
  };
  
  extern struct A a;
  
  int foo(), foo2();
  
  int main() {
  
    a.a=1;
    foo();
  }
  $
  
  $cat test1.c
  
  
  struct A {
    int a,b,c;
  };
  
   struct A  *a;
  
  int foo() {
    return 1;
  }
  
  int* bat() {
    return &a->a;
  }
  $
  
  
  
  ===== ACTUAL OUTPUT:
  $xlc -+ -q64 -qipa -c main.c
  test1.c
  main.c:
  test1.c:
  $ar -X64 r libtest.a main.o test1.o
  ar: Creating an archive file libtest.a.
  $xlc -q64 -qipa libtest.a
  1586-281 (E) A type mismatch was detected for symbol "a".
  1586-107 (S) An error was encountered during object information
  processing.
  1586-206 (S) Unresolved reference to symbol "a".
  1586-204 (S) Unresolved references to objects are detected.
  1586-341 (U) Code generation was not performed due to previously
  detected errors. Object file not created.
  $
  
  
  ====== EXPECTED OUTPUT:
  $xlc -+ -q64 -c main.c test1.c
  main.c:
  test1.c:
  $ar -X64 r libtest.a main.o test1.o
  ar: Creating an archive file libtest.a.
  xlc -q64 libtest.a
  

Local fix

• n/a
  

Problem summary

• USERS AFFECTED:
  Anyone using IPA Level 1 or higher that has exception handling
  code could theorectically run into this
  
  PROBLEM DESCRIPTION:
  The problem is that when the IPA linker finds a mismatch
  reference or definition, it just ignores it.
  If the mismatch happens to be the only definition for the
  symbol, it will treat the symbol as undefined and issue an
  error.
  
  The system linker behavior is to only fail to link under
  -qextchk.
  

Problem conclusion

• The IPA linker has been changed to conform with what the system
  linker does when -qextchk is not specified, ie accept the
  mismatch if its the only definition for the symbol.
  

Temporary fix

Comments

APAR Information

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

  IV10153

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

Fix information

• Fixed component name

  XL C/C++ FOR LI

• Fixed component ID

  5724X1400

Applicable component levels

• RB10 PSN IV10153

     UP06/09/13