cvs commit: src/lib/csu/amd64 crt1.c src/lib/csu/i386-elf crt1.c

[Bruce Evans]

bde         2005-10-07 22:13:17 UTC

  FreeBSD src repository

  Modified files:
    lib/csu/amd64        crt1.c 
    lib/csu/i386-elf     crt1.c 
  Log:
  Fixed profiling of main() for amd64 and i386.  This started rotting
  in 1993 in rev.1.5 of the i386 a.out version (csu/i386/crt0.c).
  Profiling uses a magic label "eprol" to delimit the start of the part
  of the text section covered by profiling.  This label must be placed
  before the call to main() to get main() properly profiled.  It was
  placed there in rev.1.1 of crt0.c.  Rev.1.5 imported the initial
  implementation of shared libraries in FreeBSD and misplaced the label.
  Fortunately, the misplaced label was misspelled and the old label
  wasn't removed, so the new label had no effect.  Unfortunately, when
  profiling was implemented for the ELF in 1998 in rev.1.2 of
  csu/i386-elf/crt1.c, only the incorrectly placed label was copied
  (after fixing its name).  The bug was then copied to all other arches.
  The label seems to be still misplaced in NetBSD for most arches.  It
  is in common.c for most arches so it is even further from being inside
  the function that calls main().
  
  I think "eprol" is short for "end of prologue", but it must be placed
  before the end of the prologue so that it covers main().  crt0.c has
  it before the calls atexit(_mcleanup) and monstartup(...), but it
  cannot affect these calls so I moved it after the call to monstartup().
  It now also covers the call to _init() but not the newer call to
  _init_tls().  Profiling of _init() seems to be harmless, and the call
  to _init_tls() seems to be misplaced.
  
  Reviewed by:    jdp (long ago, for a slightly different i386 version)
  
  Revision  Changes    Path
  1.15      +1 -6      src/lib/csu/amd64/crt1.c
  1.15      +1 -6      src/lib/csu/i386-elf/crt1.c