Re: PATCH: PR ld/6931: COMDAT group is broken

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Fri, Oct 3, 2008 at 2:46 AM, Alan Modra <amodra@bigpond.net.au> wrote:
> The elf.c and elflink.c patches below teach the ELF backend linker to
> handle group signature symbols for ld -r.  The genelf.em patch does
> the same for ELF targets that use the generic linker.
>
> The linker.c change fixes the group section contents for the generic
> linker, a nasty hack but nothing else seemed nice either.  Prior to
> this change, the generic linker simply copied group section contents
> to output for ld -r, which, since section indices almost always
> change, broke groups.  The generic linker also mashed together group
> sections due to lack of unique sections for groups.  Moving this logic
> from elf32.em into ldlang.c cures that particular problem.
>
> Finally, I tweaked the various emulation's place_orphan code to not
> use an existing output section statement if it did not already have a
> bfd section.  This is because a new bfd section will be created after
> all other existing sections, which is probably the wrong ordering.
> lang_place_orphan knows how to rearrange sections.
>
> bfd/
>        * elf.c (bfd_elf_set_group_contents): Assign sh_info for ld -r when
>        the signature symbol is global.
>        * elflink.c (elf_link_input_bfd): Ensure group signature symbol
>        is output when ld -r.  Set group sh_info when local.
>        * linker.c (default_indirect_link_order): Handle group sections
>        specially.
> ld/
>        * ldemul.c (ldemul_place_orphan): Add "name" param.
>        * ldemul.h (ldemul_place_orphan): Update prototype.
>        (struct ld_emulation_xfer_struct <place_orphan>): Likewise.
>        * ldlang.c (lang_place_orphans): Generate unique section names here..
>        * emultempl/elf32.em (place_orphan): ..rather than here.  Don't
>        directly use an existing output section statement that has no
>        bfd section.
>        * emultempl/pe.em (place_orphan): Likewise.
>        * emultempl/pep.em (place_orphan): Likewise.
>        * emultempl/beos.em (place_orphan): Adjust.
>        * emultempl/spuelf.em (spu_place_special_section): Adjust
>        place_orphan call.
>        * emultempl/genelf.em (gld${EMULATION_NAME}_after_open): New function.
>        (LDEMUL_AFTER_OPEN): Define.
>

It is unsafe to use an existing section symbol as group signature
since "ld -r" may change section symbol if there is a duplicate.
This patch disallows using section symbol as group signature.
OK to install?


-- 
H.J.
---

bfd/

2008-10-03  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/6931
	* elflink.c (elf_link_input_bfd): Disallow using section symbol
	as group signaure.

binutils/testsuite/

2008-10-03  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/6931
	* binutils-all/group-2.s: Don't use section symbol as group
	signature.

	* binutils-all/strip-5.d: Updated.

gas/

2008-10-03  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/6931
	* config/obj-elf.c (elf_frob_file): Disallow using section
	symbol as group signature.

gas/testsuite/

2008-10-03  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/6931
	* gas/elf/elf.exp: Run group2.

	* gas/elf/group2.l: New.
	* gas/elf/group2.s: Likewise.

ld/testsuite/

2008-10-03  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/6931
	* ld-elf/group4.d: Updated.

	* ld-elf/group7.d: New.

Attachment: binutils-grp-3.patch
Description: Binary data