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

H.J. Lu hjl.tools@gmail.com
Thu Apr 28 13:40:00 GMT 2016 
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.



-- 
H.J.
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