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[vxworks] PLT to weak symbol
- From: Nathan Sidwell <nathan at codesourcery dot com>
- To: binutils at sourceware dot org
- Date: Wed, 11 Apr 2007 10:58:57 +0100
- Subject: [vxworks] PLT to weak symbol
this patch fixes a problem that vxworks rtp has with weak symbols. Consider:
app.c
void Weak (void);
void (*const ptr) (void) = &Weak;
lib.c
void __attribute__((weak)) Weak (void) {}
This is what you get with a C++ class that has no key virtual function. Weak is
an inline virtual function.
The problem vxworks has is that .rodata (where 'ptr' resides) is relocated by
the kernel loader, and that doesn't know anything about 'Weak'. It blithely
*ignores* the relocation we emit, and we end up with a broken image.
The rtp dynamic loader is responsible for filling in relocs to Weak, but it
doesn't relocate .rodata and the like.
We already have special code to deal with the non-weak case here, and change the
reloc for ptr's initializer to refer to .plt, which the kernel loader does know
about. This patch makes it do the same thing for weak definitions too.
ok?
nathan
--
Nathan Sidwell :: http://www.codesourcery.com :: CodeSourcery
nathan@codesourcery.com :: http://www.planetfall.pwp.blueyonder.co.uk
2007-04-11 Nathan Sidwell <nathan@codesourcery.com>
* elf-vxworks.c (elf_vxworks_emit_relocs): Remap weakdef PLT slot
relocs too.
Index: elf-vxworks.c
===================================================================
RCS file: /cvs/src/src/bfd/elf-vxworks.c,v
retrieving revision 1.5
diff -c -3 -p -r1.5 elf-vxworks.c
*** elf-vxworks.c 4 Aug 2006 13:13:55 -0000 1.5
--- elf-vxworks.c 11 Apr 2007 09:46:46 -0000
*************** elf_vxworks_emit_relocs (bfd *output_bfd
*** 170,176 ****
&& *rel_hash
&& (*rel_hash)->def_dynamic
&& !(*rel_hash)->def_regular
! && (*rel_hash)->root.type == bfd_link_hash_defined
&& (*rel_hash)->root.u.def.section->output_section != NULL)
{
/* This is a relocation from an executable or shared library
--- 170,177 ----
&& *rel_hash
&& (*rel_hash)->def_dynamic
&& !(*rel_hash)->def_regular
! && ((*rel_hash)->root.type == bfd_link_hash_defined
! || (*rel_hash)->root.type == bfd_link_hash_weakdef)
&& (*rel_hash)->root.u.def.section->output_section != NULL)
{
/* This is a relocation from an executable or shared library