Re: i386-pc-solaris2.5.1: recent snapshots can't build emacs-20.2

[Jim Meyering <meyering at ascend dot com>]

"David S. Miller" <davem@dm.cobaltmicro.com> writes:

|    From: Jim Meyering <meyering@ascend.com>
|
|      414008 pure bytes used
|      ./emacs -q -batch -f list-load-path-shadows
|      make: *** [emacs] Segmentation Fault
|
|    I'm pretty sure that whatever it is about egcs that provokes
|    this was introduced in the first two weeks of June.  The 980531
|    snapshot compiled it fine, and the first time I noticed the problem
|    was about two weeks later.
|
| Thanks for the further datapoints.
|
| I am still convinced that something is going wrong with unexec when
| compiled with egcs.  The evidence in your crash indicates this to me.
|
| I ask for one further experiment if you don't mind.  Can you try
| compiling just unexelf.o with a working gcc, leave the rest the same
| (compiled with egcs which causes the crashes) and tell me the results.
|
| Also, it would be very useful if you could take the crashing emacs
| binary and run it under gdb, and look around for clues as to where it
| is crashing.  I would not be surprised if you find it crashed
| somewhere in the middle of the solaris dynamic linker, or some place
| similar.

I compiled unexelf.c using gcc-2.7.2.2 (with which I can build
a working emacs-20.2), and tried to rebuild.  Still to no avail.

  $ gdb emacs
  DISPLAY = :0.0
  TERM = xterm
  Breakpoint 1 at 0x8071a90
  Breakpoint 2 at 0x80c2055: file xterm.c, line 5241.
  (gdb) r -q -batch -f list-load-path-shadows
  Starting program: /d/pd/emacs/stable/emacs-20.2/src/emacs -q -batch -f list-load-
  path-shadows
  Breakpoint 1 at 0x801f57f0

  Program received signal SIGSEGV, Segmentation fault.
  0x0 in ?? ()
  (gdb) w
  #0  0x0 in ?? ()
  #1  0x818ced4 in __do_global_ctors_aux ()
  #2  0x818cf15 in _init ()

But it seems crtstuff.c (__do_global_ctors_aux) can't be
compiled with -g, so here's some assembly.

  Breakpoint 3, 0x818cf00 in _init ()
  (gdb) disas 0x818cf00 0x818cf21
  Dump of assembler code from 0x818cf00 to 0x818cf4f:
  0x818cf00 <_init>:      call   0x807309c <frame_dummy>
  0x818cf05 <_init+5>:    leal   0x0(%esi,1),%esi
  0x818cf09 <_init+9>:    leal   0x0(%edi,1),%edi
  0x818cf10 <_init+16>:   call   0x818ceb0 <__do_global_ctors_aux>
  0x818cf15 <_init+21>:   leal   0x0(%esi,1),%esi
  0x818cf19 <_init+25>:   leal   0x0(%edi,1),%edi
  0x818cf20 <_init+32>:   ret    $0x0
  End of assembler dump.

stepping throught that, I made it into __register_frame_info
and back to 0x818cf05.  thence into __do_global_ctors_aux:

  0x818cf10 in _init ()
  (gdb)
  0x818ceb0 in __do_global_ctors_aux ()
  (gdb) disas 0x818ceb0 0x818cef0
  Dump of assembler code from 0x818ceb0 to 0x818cef0:
  0x818ceb0 <__do_global_ctors_aux>:      pushl  %ebp
  0x818ceb1 <__do_global_ctors_aux+1>:    movl   %esp,%ebp
  0x818ceb3 <__do_global_ctors_aux+3>:    pushl  %esi
  0x818ceb4 <__do_global_ctors_aux+4>:    pushl  %ebx
  0x818ceb5 <__do_global_ctors_aux+5>:
      call   0x818ceba <__do_global_ctors_aux+10>
  0x818ceba <__do_global_ctors_aux+10>:   popl   %ebx
  0x818cebb <__do_global_ctors_aux+11>:   addl   $0x116ee,%ebx
  0x818cec1 <__do_global_ctors_aux+17>:   leal   0x6f688(%ebx),%eax
  0x818cec7 <__do_global_ctors_aux+23>:   leal   0xfffffffc(%eax),%esi
  0x818ceca <__do_global_ctors_aux+26>:   cmpl   $0xffffffff,0xfffffffc(%eax)
  0x818cece <__do_global_ctors_aux+30>:
      je     0x818cedc <__do_global_ctors_aux+44>
  0x818ced0 <__do_global_ctors_aux+32>:   movl   (%esi),%eax
  0x818ced2 <__do_global_ctors_aux+34>:   call   *%eax
  0x818ced4 <__do_global_ctors_aux+36>:   addl   $0xfffffffc,%esi
  0x818ced7 <__do_global_ctors_aux+39>:   cmpl   $0xffffffff,(%esi)
  0x818ceda <__do_global_ctors_aux+42>:
      jne    0x818ced0 <__do_global_ctors_aux+32>
  0x818cedc <__do_global_ctors_aux+44>:   leal   0xfffffff8(%ebp),%esp
  0x818cedf <__do_global_ctors_aux+47>:   popl   %ebx
  0x818cee0 <__do_global_ctors_aux+48>:   popl   %esi
  0x818cee1 <__do_global_ctors_aux+49>:   leave
  0x818cee2 <__do_global_ctors_aux+50>:   ret
  0x818cee3 <__do_global_ctors_aux+51>:   nop
  0x818cee4 <init_dummy>: pushl  %ebp
  0x818cee5 <init_dummy+1>:       movl   %esp,%ebp
  0x818cee7 <init_dummy+3>:       pushl  %ebx
  0x818cee8 <init_dummy+4>:       call   0x818ceed <init_dummy+9>
  0x818ceed <init_dummy+9>:       popl   %ebx
  0x818ceee <init_dummy+10>:      addl   $0x116bb,%ebx
  End of assembler dump.
  (gdb) stepi
  0x818ceb1 in __do_global_ctors_aux ()
  (gdb)
  0x818ceb3 in __do_global_ctors_aux ()
  (gdb)
  0x818ceb4 in __do_global_ctors_aux ()
  (gdb)
  0x818ceb5 in __do_global_ctors_aux ()
  (gdb)
  0x818ceba in __do_global_ctors_aux ()
  (gdb)
  0x818cebb in __do_global_ctors_aux ()
  (gdb)
  0x818cec1 in __do_global_ctors_aux ()
  (gdb)
  0x818cec7 in __do_global_ctors_aux ()
  (gdb)
  0x818ceca in __do_global_ctors_aux ()
  (gdb)
  0x818cece in __do_global_ctors_aux ()
  (gdb)
  0x818ced0 in __do_global_ctors_aux ()
  (gdb)
  0x818ced2 in __do_global_ctors_aux ()
  (gdb)
  0x0 in ?? ()

  Program received signal SIGSEGV, Segmentation fault.
  0x0 in ?? ()
  (gdb)