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Re: [committed, PATCH] Always create dynsym section with dynamic sections

On 04/22/16 16:24, H.J. Lu wrote:
> On Fri, Apr 22, 2016 at 2:49 PM, Faraz Shahbazker
> <> wrote:
>> On 04/22/2016 12:28 PM, H.J. Lu wrote:
>>> On Fri, Apr 22, 2016 at 11:55 AM, Faraz Shahbazker
>>>> + if (dynsymcount != 0 || elf_hash_table (info)->dynamic_sections_created)
>>>> +     ++dynsymcount;
>>> Are you saying dynamic_sections_created is 0 for MIPS here
>>> and will become 1 later?
>> No, it will remain 0. The link is static, but the hash_table is still used to
>> record global symbols that have GOT relocations against them. Ofc, this
>> hash_table does not result in creation of a dynsym section, because well,
>> dynamic_sections_created is 0.
>> Check the list of callers to bfd_elf_link_record_dynamic_symbol(), a number of
>> architectures use the link_hash_table in situations where it is not clear whether it is
>> being used to track dynamic symbols for a dynamic executable, as it is for x86.
> So MIPS doesn't have dynamic symbols in this case.  It just borrows
> dynsymcount for different purpose.  Is this correct?

Not quite! MIPS is expecting dynsymcount to count the number of symbols
that would have gone in to the .dynsym, even for a static executable. That way
parts of the arch-specific code can remain agnostic to the static/dynamic nature
of the link. It may not be used exactly as documented, but its not being used
for what one would call a different purpose.

All we need is for handling of dynsymcount when renumbering to be consistent with
its initialization. If the initial increment for a NULL symbol was not gated by
dynamic_sections_created, then the increment when renumbering should also not.
If the increment when renumbering has to be gated by dynamic_sections_created,
then the initial increment must also be so.

Faraz Shahbazker

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