(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 <i...@sandoe.co.uk> 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 <i...@sandoe.co.uk>
>
> 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.
> ---
> 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 (&use, gen_rtx_REG (DImode, R11_REG));
> + clobber_reg (&use, 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
>
