RFA: Recognize bottom of stack on Linux

[Jim Blandy <jimb@zenia.red-bean.com>]

Now, some folks feel that GDB should show the whole stack, including
_start, __libc_start_main, and anything else that's there.  However,
this isn't the way GDB has ever traditionally behaved on native
targets.  So this patch makes GDB's backtraces end after main.

2002-02-03  Jim Blandy  <jimb@redhat.com>

	* i386-linux-tdep.c (i386_linux_frame_chain): Stop the frame chain
	after `main', not just after the compilation unit containing the
	entry point.

Index: gdb/i386-linux-tdep.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/i386-linux-tdep.c,v
retrieving revision 2.7.10.1
diff -c -r2.7.10.1 i386-linux-tdep.c
*** gdb/i386-linux-tdep.c	2002/01/11 22:08:41	2.7.10.1
--- gdb/i386-linux-tdep.c	2002/02/04 02:19:28
***************
*** 352,358 ****
    if (frame->signal_handler_caller || FRAMELESS_SIGNAL (frame))
      return frame->frame;
  
!   if (! inside_entry_file (frame->pc))
      return read_memory_unsigned_integer (frame->frame, 4);
  
    return 0;
--- 352,364 ----
    if (frame->signal_handler_caller || FRAMELESS_SIGNAL (frame))
      return frame->frame;
  
!   /* On Linux, the entry point is called _start, but that invokes
!      something called __libc_start_main, which calls main.  So if we
!      want the stack to end at main (as it does for GDB's other
!      targets), the `PC in compilation unit containing entry point'
!      rule triggers too late to get us the right result.  */
!   if (! inside_entry_file (frame->pc)
!       && ! inside_main_func (frame->pc))
      return read_memory_unsigned_integer (frame->frame, 4);
  
    return 0;