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Re: RFA: don't read coff line number unless we have symbols too
- From: Jim Blandy <jimb at redhat dot com>
- To: "Philippe De Muyter" <phdm at macqel dot be>
- Cc: Joel Brobecker <brobecker at gnat dot com>,gdb-patches at sources dot redhat dot com
- Date: 26 Jun 2002 13:22:51 -0500
- Subject: Re: RFA: don't read coff line number unless we have symbols too
- References: <200206260803.g5Q83f028100@mail.macqel.be>
"Philippe De Muyter" <phdm@macqel.be> writes:
> Should the following lines not be kept outside of the conditional block ?
>
> info->min_lineno_offset = 0;
> info->max_lineno_offset = 0;
Sure, those can be moved outside.
I was just thinking of those as just establishing the pre-condition
for the loop that bfd_map_over_sections does. Those fields are never
used outside the "read the line number table" block, and the worker
function for bfd_map_over_sections --- effectively, the loop body. In
that light, it makes more sense to keep them right next to the call,
as they are in the original code.
Here's a revised patch, if you prefer the initializations outside.
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/src/src/gdb/coffread.c,v
retrieving revision 1.26
diff -c -r1.26 coffread.c
*** gdb/coffread.c 19 Mar 2002 19:00:03 -0000 1.26
--- gdb/coffread.c 26 Jun 2002 18:19:07 -0000
***************
*** 593,608 ****
/* 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, (void *) 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. */
--- 593,626 ----
/* End of warning */
info->min_lineno_offset = 0;
info->max_lineno_offset = 0;
! /* 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. */
! bfd_map_over_sections (abfd, find_linenos, (void *) 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. */