Re: [RFA] Don't apply line-number tweaks for non-GCC compilers

[Jim Blandy <jimb@redhat.com>]

For what it's worth, this change implements the suggestion I made.

Mark Kettenis <kettenis@gnu.org> writes:

>    Date: Wed, 20 Oct 2004 00:15:02 +0200 (CEST)
>    From: Mark Kettenis <mark.kettenis@xs4all.nl>
> 
> Ping!
> 
>       - GDB's stabs reader tweaks line number information, in a way that's
> 	not appropriate for non-GCC stabs.  Mark Kettenis posted a patch,
> 	and I suggested a revision; I think that's where it stands.
> 
> 	  http://sources.redhat.com/ml/gdb-patches/2004-09/msg00234.html
> 
>    I had a follow-up patch, but I lost it when I accidentally did an rm
>    -rf of my GDB working directory.  Anyway, here's a new one that
>    implements Jim's suggestion.  OK?
> 
>    I'd really like to check this in on the new release branch too, since
>    I promised to fix this a long time ago.
> 
>    Mark
> 
> 
>    Index: ChangeLog
>    from  Mark Kettenis  <kettenis@gnu.org>
> 
> 	   * dbxread.c (process_one_symbol): Do not adjust address of first
> 	   N_SLINE stab for a function for code generated by non-GCC
> 	   compilers.
> 
> 
>    Index: dbxread.c
>    ===================================================================
>    RCS file: /cvs/src/src/gdb/dbxread.c,v
>    retrieving revision 1.74
>    diff -u -p -r1.74 dbxread.c
>    --- dbxread.c 11 Sep 2004 10:24:46 -0000 1.74
>    +++ dbxread.c 19 Oct 2004 20:45:53 -0000
>    @@ -2927,11 +2927,26 @@ process_one_symbol (int type, int desc, 
> 	  /* Relocate for dynamic loading and for ELF acc fn-relative syms.  */
> 	  valu += function_start_offset;
> 
>    -      /* If this is the first SLINE note in the function, record it at
>    -	 the start of the function instead of at the listed location.  */
>    +      /* GCC 2.95.3 emits the first N_SLINE stab somwehere in the
>    +	 middle of the prologue instead of right at the start of the
>    +	 function.  To deal with this we record the address for the
>    +	 first N_SLINE stab to be the start of the function instead of
>    +	 the listed location.  We really shouldn't to this.  When
>    +	 compiling with optimization, this first N_SLINE stab might be
>    +	 optimized away.  Other (non-GCC) compilers don't emit this
>    +	 stab at all.  There is no real harm in having an extra
>    +	 numbered line, although it can be a bit annoying for the
>    +	 user.  However, it totally screws up our testsuite.
>    +
>    +	 So for now, keep adjusting the address of the first N_SLINE
>    +	 stab, but only for code compiled with GCC.  */
>    +
> 	  if (within_function && sline_found_in_function == 0)
> 	   {
>    -	  record_line (current_subfile, desc, last_function_start);
>    +	  if (processing_gcc_compilation == 2)
>    +	    record_line (current_subfile, desc, last_function_start);
>    +	  else
>    +	    record_line (current_subfile, desc, valu);
> 	     sline_found_in_function = 1;
> 	   }
> 	  else