RFC: Document GNU_PROPERTY_X86_XXX

[H.J. Lu]

On Mon, Aug 13, 2018 at 8:45 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Aug 10, 2018 at 3:40 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Fri, Aug 10, 2018 at 3:23 PM, Cary Coutant <ccoutant@gmail.com> wrote:
>>>> Add GNU_PROPERTY_X86_FEATURE_2_USED and GNU_PROPERTY_X86_FEATURE_2_NEEDED
>>>> to NT_GNU_PROPERTY_TYPE_0 note to mark processor features used and
>>>> required in x86 ELF binaries.  These 2 new properties can be used together
>>>> GNU_PROPERTY_X86_ISA_1_USED and GNU_PROPERTY_X86_ISA_1_NEEDED to describe
>>>> instruction sets and processor features contained in x86 ELF binaries.
>>>> ...
>>>> Any comments?
>>>
>>> Do you expect the FEATURE_2_USED property to be treated the same as
>>> the ISA_USED property -- namely, that if any object is missing the
>>> property (or has all zeroes), the output should not have the property?
>>
>> Yes.
>>
>>> It seems to me that you should generalize the types of merging
>>> operations that a linker is expected to perform, and encode that as
>>> part of the property, so that the linker doesn't need to special-case
>>> the handling of every new property.
>>
>> It sounds a good idea. We have
>>
>> #define GNU_PROPERTY_X86_ISA_1_USED 0xc0000000
>>
>> What is the best way to add a generic type marker to include
>> it?
>>
>
> Here is a proposal to add GNU_PROPERTY_X86_XXX. GNU_PROPERTY_X86_ISA_1_USED
> and GNU_PROPERTY_X86_ISA_1_NEEDED values are different from existing
> values.  The
> original values are left unused.   Any comments?
>

Here is the update x86-64 psABI pdf file:

https://github.com/hjl-tools/x86-psABI/wiki/x86-64-psABI-property.pdf

Binutils patches are posted at

https://sourceware.org/ml/binutils/2018-08/msg00321.html

I will check them into binutils master banch this Friday.


-- 
H.J.