[PATCH] x86-64: Fix TLSDESC relaxation for x32

[H.J. Lu]

On Sat, Jan 18, 2020 at 6:44 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Sat, Jan 18, 2020 at 3:07 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > For X32, TLSDESC sequences can be
> >
> > 8d 05 00 00 00 00       lea     x@TLSDESC(%rip), %eax
> > 67 ff 10                call    *x@TLSCALL(%eax)
> >
>
> For x32, we must encode "lea x@TLSDESC(%rip), %reg" with a REX prefix
> even if it isn't required.  Otherwise linker can’t safely perform GDesc -> LE
> optimization.  If the lea encoding has a variable length, linker can't
> tell where
> it starts.  Here is the updated patch to always generate a REX prefix.
>

Here is the updated patch to handle  GDesc -> IE optimization.
BTW, I posted x86-64 psABI update at

https://gitlab.com/x86-psABIs/x86-64-ABI/merge_requests/4


-- 
H.J.
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