Re: [x32] Allow R_X86_64_64

["Jan Beulich" <JBeulich at novell dot com>]

>>> On 12.08.11 at 15:22, "H.J. Lu" <hjl.tools@gmail.com> wrote:
> On Fri, Aug 12, 2011 at 6:17 AM, Jan Beulich <JBeulich@novell.com> wrote:
>>>>> On 12.08.11 at 14:09, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>>> On Fri, Aug 12, 2011 at 12:30 AM, Jan Beulich <JBeulich@novell.com> wrote:
>>>>>>> On 12.08.11 at 06:37, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>>>>> On Mon, Aug 1, 2011 at 3:15 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>>> Hi,
>>>>>>
>>>>>> It turns out that x32 needs R_X86_64_64.  One major reason is
>>>>>> the displacement range of x32 is -2G to +2G.  It isn't a problem
>>>>>> for compiler since only small model is required for x32.
>>>>>>
>>>>>> However, to address 0 to 4G directly in assembly code, we have
>>>>>> to use R_X86_64_64 with movabs.  I am checking the follow patch
>>>>>> into x32 psABI to allow R_X86_64_64.
>>>>>>
>>>>>>
>>>>>
>>>>> X32  Linker should treats R_X86_64_64 as R_X86_64_32
>>>>> zero-extended to 64bit for output.  I will update x32 psABI with
>>>>
>>>> I'm sorry to say that, but the situation about x32 seems to be
>>>> getting worse with each change you do, every time again
>>>> revolving around mixing up ABI specification and a particular
>>>> implementation thereof.
>>>>
>>>> Here, if you need something zero-extended (though I can't see
>>>> why you would), then you should use a new relocation type. As
>>>> pointed out before, there are valid possible uses of R_X86_64_64
>>>> that would require the semantics of x86-64.
>>>>
>>>
>>> When does x32 need the semantics of x86-64 for R_X86_64_64?
>>
>> When referencing an assembler or linker defined constant that
>> exceeds 32-bit in width. Given that this is a 64-bit architecture
>> with 32-bit addresses, at least I would expect such to work.
>>
> 
> Yes, it should work just fine for x32 by zero-extending 32bit
> address to 64bit.

For a constant that has more than 32 significant bits???

Jan