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Re: [RFC][PATCH] Check ELF relocs after opening all all input files
- From: Alan Modra <amodra at gmail dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: Nick Clifton <nickc at redhat dot com>, Binutils <binutils at sourceware dot org>
- Date: Thu, 28 Apr 2016 22:37:07 +0930
- Subject: Re: [RFC][PATCH] Check ELF relocs after opening all all input files
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On Thu, Apr 28, 2016 at 05:49:57AM -0700, H.J. Lu wrote:
> On Wed, Apr 27, 2016 at 6:11 PM, Alan Modra <amodra@gmail.com> wrote:
> > On Wed, Apr 27, 2016 at 03:24:48PM -0700, H.J. Lu wrote:
> >> bfd_elf_record_link_assignment
> >> is called after check_relocs. bfd_elf_record_link_assignment sets non_elf,
> >> def_regular and forced_local. For PROVIDE, it also updates root.type. They
> >> are needed in reloc_checks.
> >
> > My guess is that symbol twiddling done in before_allocation should be
> > moved to a new ldemul hook called at the start of lang_do_assignments.
> > The idea being to stabilize symbols earlier.
> >
> > The hook would twiddle __ehdr_start and call find_statement_assignment
> > when lang_mark_phase_enum. Reversing the __ehdr_start twiddle stays
> > in before_allocation.
> >
>
> I tried this. But it doesn't work with __start/__stop symbols. I
> need to know if they are defined and referenced local in check_relocs.
[snip]
> --- a/ld/ldlang.c
> +++ b/ld/ldlang.c
> @@ -6930,6 +6930,8 @@ lang_process (void)
> collection in order to make sure that all symbol aliases are resolved. */
> lang_do_assignments (lang_mark_phase_enum);
>
> + ldemul_record_link_assignments (lang_mark_phase_enum);
> +
> lang_do_memory_regions();
> expld.phase = lang_first_phase_enum;
You'll need to run ldemul_record_link_assignments before
lang_do_assignments if you want provided symbols to be defined.
I suggest renaming to ldemul_do_assignments and putting
ldemul_do_assignments (phase);
inside lang_do_assignments just before the call to
lang_do_assignments_1.
--
Alan Modra
Australia Development Lab, IBM