[PATCH] Add a record_link_assignments hook to ldemul

[H.J. Lu]

On Thu, Apr 28, 2016 at 10:11 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Apr 28, 2016 at 6:40 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, Apr 28, 2016 at 6:09 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> 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.
>>>>
>>
>> With this patch, I only got 2 failures on x86-64.
>>
>
> This one works for both i386 and x86-64.
>

This is the complete patch.  OK for master?


-- 
H.J.
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