IZ67844: NESTING UNDERFLOW ISSUE WITH -G

October 2010 PTF for XL C/C++ for AIX, V10.1
October 2010 PTF for XL C for AIX, V10.1
May 2012 PTF for XL C/C++ for AIX, V10.1
January 2013 PTF for XL C for AIX, V10.1
January 2013 PTF for XL C/C++ for AIX, V10.1
XL C/C++ for AIX Fix Pack 18 (July 2013 PTF) for 10.1
XL C/C++ for AIX Fix Pack 19 (October 2013 PTF) for 10.1
XL C/C++ for AIX Fix Pack 21 (October 2015 PTF) for 10.1
XL C for AIX Fix Pack 21 (October 2015 PTF) for 10.1
March 2010 PTF for XL C for AIX, V10.1
March 2010 PTF for XL C/C++ for AIX, V10.1
April 2010 PTF for XL C for AIX, V10.1
April 2010 PTF for XL C/C++ for AIX, V10.1
June 2010 PTF for XL C/C++ for AIX, V10.1
June 2010 PTF for XL C for AIX, V10.1
February 2011 PTF for XL C for AIX, V10.1
May 2011 PTF for XL C/C++ for AIX, V10.1
May 2011 PTF for XL C for AIX, V10.1
October 2011 PTF for XL C/C++ for AIX, V10.1
October 2011 PTF for XL C for AIX, V10.1
February 2012 PTF for XL C for AIX, V10.1
February 2012 PTF for XL C/C++ for AIX, V10.1
May 2012 PTF for XL C for AIX, V10.1
September 2012 PTF for XL C for AIX, V10.1
September 2012 PTF for XL C/C++ for AIX, V10.1
XL C for AIX Fix Pack 18 (July 2013 PTF) for 10.1
XL C for AIX Fix Pack 19 (October 2013 PTF) for 10.1
XL C for AIX Fix Pack 20 (October 2014 PTF) for 10.1
XL C/C++ for AIX Fix Pack 20 (October 2014 PTF) for 10.1

APAR status

• Closed as program error.

Error description

• The assembler produces a 'nested underflow' error when -g is
  specified for code that contains inline asm.
  

Local fix

• N/A
  

Problem summary

• USER AFFECTED:
  Users compiling a file with -g that contains asm constructs
  and static data requiring code to initialize (eg. static
  objects with constructors)
  are affected by this issue.
  
  PROBLEM DESCRIPTION:
  There are a pair of directives that define begin and
  end of inlined code. These directives need to be
  translated in the asm path into directives for the
  assembler. The code that emits the begining of the
  inlined code is supposed to emit .bf directive with
  a line number stating where the function begins.
  The corresponding .ef directive is emited later.
  It turns out that init code does not have a line number
  so emitting a .bf with a line number of zero would
  be useless, so it was not emitted. What we neglected
  to do is refrain from emitting a .ef when line number
  is zero. This caused the unmatched .bf .ef assembler
  directives.
  

Problem conclusion

• The compiler has been fixed to avoid this assembler error
  message.
  

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:

  LI75574 LI75606

Fix information

• Fixed component name

  XL C AIX

• Fixed component ID

  5724U8000

Applicable component levels