On Fri, Jul 9, 2021 at 10:25 AM Iain Sandoe wrote:
>
> (early) ping;
> if possible I’d like to get this onto master in time to back-port for 11.2.
>
> > On 4 Jul 2021, at 21:08, Iain Sandoe wrote:
> >
> > Hi,
> >
> > (I’m not going to defend the status quo here, it seems a bit prone
> > to confusing a user [different interposition behaviour between the
> > inlined and non-inlined cases] however, this is what the platform
> > compilers implement).
> >
> >
> >
> > We allow public functions defined in a TU to bind locally for PIC
> > code (the default) on 64bit Mach-O.
> >
> > If such functions are not inlined, we cannot tell at compile-time if
> > they might be called via the lazy symbol resolver (this can depend on
> > options given at link-time). Therefore, we must assume that the lazy
> > resolver could be used which clobbers R11 and R10.
> >
> > The solution here is similar in form to the one used for veneer regs
> > on Arm (but I’m open to alternate suggestions).
> >
> > tested on X86_64-darwin, linux
> > OK for master?
> > Iain
> >
> > Signed-off-by: Iain Sandoe
> >
> > PR target/100152 - [10/11/12 Regression] used caller-saved register not
> > preserved across a call.
> >
> >PR target/100152
> >
> > gcc/ChangeLog:
> >
> > * config/i386/i386-expand.c (ix86_expand_call): If a call is
> > to a non-local-binding, or local but to a public symbol, then
> > assume that it might be indirected via the lazy symbol binder.
> > Mark R10 and R10 as clobbered in that case.
LGTM, but this is Darwin specific patch, so you could approve it yourself.
Uros.
> > ---
> > gcc/config/i386/i386-expand.c | 16 +++-
> > 1 file changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c
> > index b37642e35ee..1b860e027b0 100644
> > --- a/gcc/config/i386/i386-expand.c
> > +++ b/gcc/config/i386/i386-expand.c
> > @@ -8380,6 +8380,7 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx
> > callarg1,
> > pop = NULL;
> > gcc_assert (!TARGET_64BIT || !pop);
> >
> > + rtx addr = XEXP (fnaddr, 0);
> > if (TARGET_MACHO && !TARGET_64BIT)
> > {
> > #if TARGET_MACHO
> > @@ -8392,7 +8393,6 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx
> > callarg1,
> > /* Static functions and indirect calls don't need the pic register.
> > Also,
> >check if PLT was explicitly avoided via no-plt or "noplt" attribute,
> > making
> >it an indirect call. */
> > - rtx addr = XEXP (fnaddr, 0);
> > if (flag_pic
> > && GET_CODE (addr) == SYMBOL_REF
> > && !SYMBOL_REF_LOCAL_P (addr))
> > @@ -8555,6 +8555,20 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx
> > callarg1,
> > }
> > }
> >
> > + if (TARGET_MACHO && TARGET_64BIT && !sibcall
> > + && ((GET_CODE (addr) == SYMBOL_REF && !SYMBOL_REF_LOCAL_P (addr))
> > + || !fndecl || TREE_PUBLIC (fndecl)))
> > +{
> > + /* We allow public functions defined in a TU to bind locally for PIC
> > + code (the default) on 64bit Mach-O.
> > + If such functions are not inlined, we cannot tell at compile-time if
> > + they will be called via the lazy symbol resolver (this can depend on
> > + options given at link-time). Therefore, we must assume that the lazy
> > + resolver could be used which clobbers R11 and R10. */
> > + clobber_reg (, gen_rtx_REG (DImode, R11_REG));
> > + clobber_reg (, gen_rtx_REG (DImode, R10_REG));
> > +}
> > +
> > if (vec_len > 1)
> > call = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (vec_len, vec));
> > rtx_insn *call_insn = emit_call_insn (call);
> > --
> > 2.24.1
> >
>
