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Re: [PATCH] Disallow copy relocation against protected data symbol
On Fri, Aug 25, 2017 at 05:17:51AM -0700, H.J. Lu wrote:
> On Thu, Aug 24, 2017 at 11:22 PM, Alan Modra <email@example.com> wrote:
> > On Thu, Aug 24, 2017 at 09:13:15AM -0700, H.J. Lu wrote:
> >> property. This patch adds a bit to elf_link_hash_entry and elf_obj_tdata
> > Why is def_protected needed? Surely it is wrong to record the
> > visibility of a symbol that may not even be the final definition?
> > Why not just use visibility directly?
> ELF_ST_VISIBILITY is only merged with relocatable input. We don't
> mark an undefined symbol as protected just because the definition comes
> from a protected symbol in a shared object. A protected symbol is
> meaningful only for a definition with dynamic relocation.
> def_protected is updated every time when def_regular or def_dynamic
> is set. It tracks the visibility of the symbol definition, which can be
> different from the visibility of the symbol reference. It reflects the
> visibility of the final definition.
OK, thanks for the explanation. Since the flag is only used by the
x86 backends, please move it to elf_i386_link_hash_entry and
elf_x86_64_link_hash_entry. You can set it via
elf_backend_merge_symbol and rearrange _bfd_elf_merge_symbol a little
so that bed->merge_symbol is called before the bfd_link_hash_new early
Australia Development Lab, IBM