[PATCH] PR ld/18720: Properly merge hidden versioned symbol

[Alan Modra]

On Mon, Nov 21, 2016 at 01:09:20PM -0800, H.J. Lu wrote:
> On Sun, Nov 20, 2016 at 7:09 PM, Alan Modra <amodra@gmail.com> wrote:
> > On Wed, Aug 05, 2015 at 07:43:21PM -0700, H.J. Lu wrote:
> >> I will check it in this Friday unless there is an objection.
> >
> > HJ, git 6e33951edc change to elf_link_output_extsym where you
> > introduce local_bind, is broken.  You can't change global syms to
> > STB_LOCAL that late, after _bfd_elf_link_renumber_dynsyms, as otherwise
> > you run the risk of ordering STB_LOCAL symbols after global symbols.
> > The ELF gABI is clear that "all symbols with STB_LOCAL binding precede
> > the weak and global symbols".  (It's also wrong to test flags on a
> > bfd_link_hash_warning symbol.)
> >
> > I don't have a testcase for you.  I noticed the bug when looking at
> > PR20828.  Please revert the elf_link_output_extsym change and
> > implement by setting forced_local before the last run of
> > _bfd_elf_link_renumber_dynsyms.
> >
> 
> How about this patch?

OK thanks, it looks almost the same as the one I threw together.

You could also move the code hiding weak undefined non-default
visibility symbols.

  /* If a weak undefined symbol has non-default visibility, we also
     hide it from the dynamic linker.  */
  if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
      && h->root.type == bfd_link_hash_undefweak)
    (*bed->elf_backend_hide_symbol) (eif->info, h, TRUE);

  /* A hidden versioned symbol in executable should be forced local if
     it is is locally defined, not referenced by shared library and not
     exported.  */
  else if (bfd_link_executable (eif->info)
etc.

-- 
Alan Modra
Australia Development Lab, IBM