Re: [RFC][PATCH] Check ELF relocs after opening all all input files

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

On Thu, Apr 28, 2016 at 6:07 AM, Alan Modra <amodra@gmail.com> wrote:
> 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 got many more failures when I did that since many assignments
haven't been processed yet.

> 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



-- 
H.J.