Re: RFA: don't read coff line number unless we have symbols too

[Daniel Jacobowitz <drow@mvista.com>]

You may want to contact him (MAINTAINERS says Philippe De Muyter,
phdm@macqel.be) directly.  I've never once seen him on this list.

On Thu, Jun 20, 2002 at 01:26:48PM -0500, Jim Blandy wrote:
> 
> Ping to the COFF maintainer: this patch needs review.
> 
> Jim Blandy <jimb@redhat.com> writes:
> 
> > 2002-03-06  Jim Blandy  <jimb@redhat.com>
> > 
> > 	* coffread.c (coff_symfile_read): Don't try to read the line
> > 	number table from disk if the image file doesn't have a symbol
> > 	table; we'll never actually look at the info anyway, and Windows
> > 	ships DLL's with bogus file offsets for the line number data.
> > 
> > Index: gdb/coffread.c
> > ===================================================================
> > RCS file: /cvs/cvsfiles/devo/gdb/coffread.c,v
> > retrieving revision 1.182
> > diff -c -r1.182 coffread.c
> > *** gdb/coffread.c	2001/09/25 02:35:52	1.182
> > --- gdb/coffread.c	2002/03/06 23:12:00
> > ***************
> > *** 622,637 ****
> >   
> >   /* End of warning */
> >   
> > !   /* Read the line number table, all at once.  */
> > !   info->min_lineno_offset = 0;
> > !   info->max_lineno_offset = 0;
> > !   bfd_map_over_sections (abfd, find_linenos, (PTR) info);
> >   
> > !   make_cleanup (free_linetab_cleanup, 0 /*ignore*/);
> > !   val = init_lineno (abfd, info->min_lineno_offset,
> > ! 		     info->max_lineno_offset - info->min_lineno_offset);
> > !   if (val < 0)
> > !     error ("\"%s\": error reading line numbers\n", name);
> >   
> >     /* Now read the string table, all at once.  */
> >   
> > --- 622,654 ----
> >   
> >   /* End of warning */
> >   
> > !   /* Only read line number information if we have symbols.
> >   
> > !      On Windows NT, some of the system's DLL's have sections with
> > !      PointerToLinenumbers fields that are non-zero, but point at
> > !      random places within the image file.  (In the case I found,
> > !      KERNEL32.DLL's .text section has a line number info pointer that
> > !      points into the middle of the string `lib\\i386\kernel32.dll'.)
> > ! 
> > !      However, these DLL's also have no symbols.  The line number
> > !      tables are meaningless without symbols.  And in fact, GDB never
> > !      uses the line number information unless there are symbols.  So we
> > !      can avoid spurious error messages (and maybe run a little
> > !      faster!) by not even reading the line number table unless we have
> > !      symbols.  */
> > !   if (num_symbols > 0)
> > !     {
> > !       /* Read the line number table, all at once.  */
> > !       info->min_lineno_offset = 0;
> > !       info->max_lineno_offset = 0;
> > !       bfd_map_over_sections (abfd, find_linenos, (PTR) info);
> > ! 
> > !       make_cleanup (free_linetab_cleanup, 0 /*ignore*/);
> > !       val = init_lineno (abfd, info->min_lineno_offset,
> > !                          info->max_lineno_offset - info->min_lineno_offset);
> > !       if (val < 0)
> > !         error ("\"%s\": error reading line numbers\n", name);
> > !     }
> >   
> >     /* Now read the string table, all at once.  */
> >   
> 

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer