[PATCH] gold: Ignore definition from a dynamic object for __start/__stop

[Cary Coutant]

>> I think the must_be_in_reg flag is unnecessary -- only_if_ref should
>> be sufficient. I looked through all the symbols that are created with
>
> As Alan mentioned, __start and __stop symbols must be exported,
> but not preempted.  STV_PROTECTED should be used.
>
>> only_if_ref true, and they all look like they should ignore
>> definitions (and references) in dynamic objects:
>>
>>   __rel_iplt_start (global hidden)
>>   __rel_iplt_end (global hidden)
>>  __exidx_start (arm, global hidden)
>>   __exidx_end (arm, global hidden)
>>   _TLS_MODULE_BASE_ (local hidden)
>>   __preinit_array_start (global hidden)
>>   __preinit_array_end (global hidden)
>>   __init_array_start (global hidden)
>>   __init_array_end (global hidden)
>>   __fini_array_start (global hidden)
>>   __fini_array_end (global hidden)
>>   __stack (global default)
>>   __executable_start (global default)
>>   __ehdr_start (global hidden)
>>   etext, _etext, __etext (global default)
>>   edata (global default)
>>   end (global default)
>>
>> Certainly the ones that are hidden should ignore both defs and refs in
>> dynamic objects. The others (__stack, __executable_start, [_][_]etext,
>> edata, and end) should at least ignore defs in dynamic objects.

You didn't answer why you think it's not reasonable to use only_if_ref
by itself, rather than adding the new must_be_in_reg flag.

-cary