Fix PR12762 using linkonce sections in plugin bfd

[H.J. Lu]

On Sat, Aug 13, 2011 at 7:31 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Sat, Aug 13, 2011 at 2:59 AM, Alan Modra <amodra@gmail.com> wrote:
>> Revised patch.  This one gives the plugin comdat_key symbols sections
>> named .gnu.linkonce.t.<comdat_key>, so that SEC_LINK_ONCE gets set for
>> the sections when recreating them during bfd_make_readable().
>>
>> I've also given the COFF backend its own bfd_section_already_linked
>> and tidied the existing bfd_section_already_linked functions.  I'd
>> appreciate someone familiar with our COFF support reviewing
>> _bfd_coff_section_already_linked in case I've made some glaring
>> mistakes..  The old code basically matched on section name, but if
>> both sections had a comdat symbol then the symbols had to match too.
>> That meant a comdat section could match a non-comdat section with the
>> same name, something the new code specifically disallows, and anyway
>> is a side-effect of hashing on the comdat key.  COFF also gets the
>> benefit of the ELF code for SEC_LINK_DUPLICATES_SAME_CONTENTS, so
>> section contents are actually checked now.
>>
>> bfd/
>>        PR ld/12762
>>        * bfd-in.h (struct bfd_section_already_linked): Forward declare.
>>        (_bfd_handle_already_linked): Declare.
>>        * coff-alpha.c (_bfd_ecoff_section_already_linked): Define as
>>        _bfd_coff_section_already_linked.
>>        * coff-mips.c (_bfd_ecoff_section_already_linked): Likewise.
>>        * coffcode.h (coff_section_already_linked): Likewise.
>>        * cofflink.c (coff_link_add_symbols): Revert 2011-07-09 changes.
>>        * elf-bfd.h: Likewise.
>>        * libbfd-in.h: Likewise.
>>        * targets.c: Likewise.
>>        * linker.c (bfd_section_already_linked): Likewise.
>>        (bfd_section_already_linked_table_lookup): Likewise.
>>        (bfd_section_already_linked_table_insert): Likewise.
>>        (_bfd_generic_section_already_linked): Likewise.  Call
>>        _bfd_handle_already_linked.
>>        (_bfd_handle_already_linked): New function, split out from..
>>        * elflink.c (_bfd_elf_section_already_linked): ..here.  Revert
>>        2011-07-09 changes.  Avoid unnecessary strcmp when matching
>>        already_linked_list entries.  Match plugin linkonce section.
>>        (section_signature): Delete.
>>        * coffgen.c (_bfd_coff_section_already_linked): New function.
>>        * libcoff-in.h (_bfd_coff_section_already_linked): Declare.
>>        * libbfd.h: Regenerate.
>>        * libcoff.h: Regenerate.
>>        * bfd-in2.h: Regenerate.
>> ld/
>>        PR ld/12762
>>        * ldlang.c (section_already_linked): Revert 2011-07-09 changes.
>>        * plugin.c: Likewise.
>>        (asymbol_from_plugin_symbol): Create linkonce section for syms
>>        with comdat_key.
>>
>
> It works.
>

I got:

ld: BFD (Linux/GNU Binutils) 2.21.53.0.3.20110813 assertion fail
/net/gnu-6/export/linux/src/binutils/binutils/bfd/elflink.c:12634

on a Linux/x86-64 kernel driver build.

-- 
H.J.