V2 [PATCH] x86: Support GNU_PROPERTY_X86_ISA_1_V[234] marker:

[H.J. Lu]

On Tue, Oct 13, 2020 at 4:29 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu:
>
> > On Tue, Oct 13, 2020 at 3:48 AM Florian Weimer <fweimer@redhat.com> wrote:
> >>
> >> * H. J. Lu via Binutils:
> >>
> >> > Here is the updated patch with -z x86-64-v[234] linker command line
> >> > option to mark x86-64-v[234] ISA level as needed.
> >>
> >> I think this needs a marker for the baseline as well.  Currently, a
> >> missing marker can either mean “the programmer did not specify a marker”
> >> or “the object uses the baseline ABI”.
> >>
> >
> > “the object uses the baseline ABI” and “the programmer did not specify
> > a marker” mean the same thing to ld.so since a baseline or
> > x86-64-v[234] objects may contain ANY instructions.
>
> ld.so won't be the sole consumer of such annotations.  For example, an
> install-like tool could use the annotations to select the appropriate
> installation path for an ELF shared object.
>

They should treat “the object uses the baseline ABI” the same way as
“the programmer did not specify a marker” since the ISA marker specifies
the minimum ISA level, not the maximum.

-- 
H.J.