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[RFC] [gold] Simplify relocation strategy logic

Richard Sandiford richard.sandiford@linaro.org
Mon Mar 14 16:43:00 GMT 2011 
Richard Sandiford <richard.sandiford@linaro.org> writes:
> Cary Coutant <ccoutant@google.com> writes:
>>> I don't believe this is correct.  ABSOLUTE_REF is defined as:
>>>
>>>    // A reference to the symbol's absolute address.  This includes
>>>    // references that cause an absolute address to be stored in the GOT.
>>>    ABSOLUTE_REF = 1,
>>>
>>> and the final symbol reference (by the GOT entry) is absolute
>>> in all these cases.  ("Absolute in GOT" was supposed to mean
>>> "an absolute reference _in_ the global offset table", not "to".)
>>> Whether the reference to the GOT entry itself is absolute, relative
>>> to the GP, or relative to the PC, isn't modelled by these flags.
>>>
>>> Does the patch rely on this, or was it just something you noticed
>>> by inspection?
>>
>> My understanding of the ABI is that R_X86_64_GOTPCREL is a pc-relative
>> relocation to the GOT entry, and R_X86_64_GOTPLT64 is an absolute
>> reference to a GOT entry. In both cases, I believe the GOT entry
>> itself is expected to contain an absolute address.
>
> Right.

Er, that was "right" to the last bit.  R_X86_64_GOTPLT64 is a GOT offset,
isn't it?  That's GP-relative rather than absolute.

Richard
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