IV72769: DWARF DEBUG INFO INFLATING OBJECT FILE SIZE

XL C/C++ for AIX Fix Pack 3 (April 2015 PTF) for 13.1
XL C/C++ for AIX Fix Pack 4 (July 2015 PTF) for 13.1
XL C for AIX Fix Pack 5 (November 2015 Update) for 13.1
XL C/C++ for AIX Fix Pack 5 (November 2015 PTF) for 13.1
XL C/C++ for AIX Fix Pack 6 (February 2016 PTF) for 13.1
XL C for AIX Fix Pack 6 (February 2016 Update) for 13.1
XL C for AIX Fix Pack 7 (May 2016 Update) for 13.1
XL C/C++ for AIX Fix Pack 7 (May 2016 PTF) for 13.1
XL C for AIX Fix Pack 8 (August 2016 Update) for 13.1
XL C/C++ for AIX Fix Pack 8 (August 2016 PTF) for 13.1
XL C for AIX Fix Pack 9 (June 2017 Update) for 13.1
XL C/C++ for AIX Fix Pack 9 (June 2017 PTF) for 13.1
XL C for AIX Fix Pack 10 (February 2018 Update) for 13.1
XL C/C++ for AIX Fix Pack 10 (February 2018 PTF) for 13.1
XL C for AIX Fix Pack 3 (April 2015 PTF) for 13.1
XL C for AIX Fix Pack 4 (July 2015 PTF) for 13.1
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

APAR status

• Closed as program error.

Error description

• When generating object files with debug information in the DWARF
  format, the files generated are much larger than files using the
  stabstring debug format.
  
  In general, DWARF debug information is typically larger than
  stabstring debug information.  However in this case, object
  files with DWARF debug info are sometimes 10 times or more the
  size of stabstring object files.
  
  
  
      === TEST CASE ===
  
  int main()
  {
          return 5;
  }
  
  
  > xlc -c -g test.c -qdbgfmt=dwarf      -o test.dwarf.o
  > xlc -c -g test.c -qdbgfmt=stabstring -o test.stabstring.o
  > ls -l
  -rw-r-----    1      26  test.c
  -rw-r-----    1   22963  test.dwarf.o
  -rw-r-----    1    1275  test.stabstring.o
  >
  

Local fix

• NA
  

Problem summary

• USERS AFFECTED:
  DWARF usersPROBLEM DESCRIPTION:
  Compiling files with '-g -qdbgfmt=dwarf' will result in DWARF
  debug info that massively inflates object file size.
  
  USERS AFFECTED:
  DWARF users
  

Problem conclusion

• When the compiler internally generates the object file layout,
  the size footprint occupies more space than needed, which makes
  the resulting object file much larger when generating DWARF
  debug information.  The issue has been corrected, and smaller
  object files will be seen.
  

Temporary fix

Comments

APAR Information

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

  IV67196

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

Fix information

• Fixed component name

  XL C FOR AIX

• Fixed component ID

  5725C7100

Applicable component levels

• RD10 PSY