[PATCH] fix PR symtab/15597

[nick clifton]

Hi Tom,

> This patch touches BFD.  Previously, gdb had its own code for parsing
> .gnu_debugaltlink; I changed it to use the BFD functions after those
> were introduced.  However, the BFD functions are incorrect -- they
> assume that .gnu_debugaltlink is formatted like .gnu_debuglink.
> However, it it is not.  Instead, it consists of a file name followed
> by the build-id -- no alignment, and the build-id is not a CRC.
>
> Fixing this properly is a bit of a pain.  But, because
> separate_alt_debug_file_exists just has a FIXME for the build-id case,
> I did not fix it properly.  Instead I introduced a hack.  This leaves
> BFD working just as well as it did before my patch.
>
> I'm willing to do something better here but I could use some guidance
> as to what.  It seems that the build-id code in BFD is largely punted
> on.

True - it would be nice to see this fixed, but it can be left for a 
future patch.


> 	* bfd-in2.h: Rebuild.
> 	* opncls.c (bfd_get_alt_debug_link_info): Add buildid_len
> 	parameter.  Change type of buildid_out.  Update.
> 	(get_alt_debug_link_info_shim): New function.
> 	(bfd_follow_gnu_debuglink): Use it.
>
> 	* Makefile.in (SFILES): Add build-id.c.
> 	(HFILES_NO_SRCDIR): Add build-id.h.
> 	* build-id.c: New file, largely from elfread.c.  Modified
> 	most functions.
> 	* build-id.h: New file.
> 	* dwarf2read.c (dwarf2_get_dwz_file): Update for change to
> 	bfd_get_alt_debug_link_info.  Verify dwz file's build-id.
> 	Search for dwz file using build-id.
> 	* elfread.c (build_id_bfd_get, build_id_verify)
> 	(build_id_to_debug_filename, find_separate_debug_file): Remove.
>

Approved - please apply.

Cheers
   Nick