[PATCH] Implement __builtin_thread_pointer for x86 TLS

[Hongtao Liu]

On Wed, Sep 9, 2020 at 2:35 PM Jakub Jelinek <jakub@redhat.com> wrote:
>
> On Wed, Sep 09, 2020 at 10:30:46AM +0800, Hongtao Liu wrote:
> > From 400418fadce46e7db7bd37be45ef5ff5beb08d19 Mon Sep 17 00:00:00 2001
> > From: liuhongt <hongtao.liu@intel.com>
> > Date: Tue, 8 Sep 2020 15:44:58 +0800
> > Subject: [PATCH] Implement __builtin_thread_pointer for x86 TLS.
> >
> > gcc/ChangeLog:
> >       PR target/96955
> >       * config/i386/i386.md (get_thread_pointer<mode>): New
> >       expander.
> >
> > gcc/testsuite/ChangeLog:
> >
> >       * gcc.target/i386/builtin_thread_pointer.c: New test.
> > ---
> >  gcc/config/i386/i386.md                       | 10 +++++++
> >  .../gcc.target/i386/builtin_thread_pointer.c  | 28 +++++++++++++++++++
> >  2 files changed, 38 insertions(+)
> >  create mode 100644 gcc/testsuite/gcc.target/i386/builtin_thread_pointer.c
> >
> > diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> > index 446793b78db..2f6eb0a7b98 100644
> > --- a/gcc/config/i386/i386.md
> > +++ b/gcc/config/i386/i386.md
> > @@ -15433,6 +15433,16 @@ (define_insn_and_split "*tls_local_dynamic_32_once"
> >        (clobber (reg:CC FLAGS_REG))])])
> >
> >  ;; Load and add the thread base pointer from %<tp_seg>:0.
> > +(define_expand "get_thread_pointer<mode>"
> > +  [(set (match_operand:PTR 0 "register_operand")
> > +     (unspec:PTR [(const_int 0)] UNSPEC_TP))]
> > +  ""
> > +{
> > +  /* targetm is not existed in the scope of condition.  */
>
> Reword as "targetm is not visible in the scope of the condition."
> In fact, even if it was, it wouldn't help, because expand_builtin_thread_pointer
> assumes that if the expander exists, then it will work and emit some code
> and emits the error only if the expander doesn't exist.
>
> Ok for trunk with that change, thanks.
>

Thanks for the review.

> > +  if (!targetm.have_tls)
> > +    error ("%<__builtin_thread_pointer%> is not supported on this target");
> > +})
> > +
>
>         Jakub
>


-- 
BR,
Hongtao