> On Mon, Feb 26, 2018 at 7:06 AM, Jan Hubicka <hubi...@ucw.cz> wrote:
> >> On Mon, Feb 26, 2018 at 2:58 AM, Jan Hubicka <hubi...@ucw.cz> wrote:
> >> >> On Mon, Feb 26, 2018 at 2:05 AM, Martin Liška <mli...@suse.cz> wrote:
> >> >> > On 02/25/2018 02:37 AM, H.J. Lu wrote:
> >> >> >> PR target/r84530
> >> >> >
> >> >> > Just a nit I've noticed:
> >> >> >
> >> >> > s/r84530/84530
> >> >>
> >> >> Fixed.
> >> >>
> >> >> --
> >> >> H.J.
> >> >
> >> >> From f08b8721ed038cefcee5a0bb1329b90a2d322269 Mon Sep 17 00:00:00 2001
> >> >> From: "H.J. Lu" <hjl.to...@gmail.com>
> >> >> Date: Sat, 24 Feb 2018 05:05:49 -0800
> >> >> Subject: [PATCH] i386: Update -mfunction-return= for return with pop
> >> >>
> >> >> When -mfunction-return= is used, simple_return_pop_internal should pop
> >> >> return address into ECX register, adjust stack by bytes to pop from
> >> >> stack
> >> >> and jump to the return thunk via ECX register.
> >> >>
> >> >> Tested on i686 and x86-64.
> >> >>
> >> >> PR target/84530
> >> >> * config/i386/i386-protos.h (ix86_output_indirect_jmp): Remove
> >> >> the bool argument.
> >> >> (ix86_output_indirect_function_return): New prototype.
> >> >> (ix86_split_simple_return_pop_internal): Likewise.
> >> >> * config/i386/i386.c (indirect_return_via_cx): New.
> >> >> (indirect_return_via_cx_bnd): Likewise.
> >> >> (indirect_thunk_name): Handle return va CX_REG.
> >> >> (output_indirect_thunk_function): Create alias for
> >> >> __x86_return_thunk_[re]cx and __x86_return_thunk_[re]cx_bnd.
> >> >> (ix86_output_indirect_jmp): Remove the bool argument.
> >> >> (ix86_output_indirect_function_return): New function.
> >> >> (ix86_split_simple_return_pop_internal): Likewise.
> >> >> * config/i386/i386.md (*indirect_jump): Don't pass false
> >> >> to ix86_output_indirect_jmp.
> >> >> (*tablejump_1): Likewise.
> >> >> (simple_return_pop_internal): Change it to define_insn_and_split.
> >> >> Call ix86_split_simple_return_pop_internal to split it for
> >> >> -mfunction-return=.
> >> >> (simple_return_indirect_internal): Call
> >> >> ix86_output_indirect_function_return instead of
> >> >> ix86_output_indirect_jmp.
> >> >
> >> > It seems to make sense. Since LLVM has picked up our thunk names now,
> >> > I wonder if they have same bug or someohow already assigned a name
> >> > to this thunk. In the second case we probably ought to match it. Do
> >> > you know what LLVM uses?
> >> >
> >>
> >> I don't think LLVM has implemented -mfunction-return=. I disclosed
> >> my -mindirect-branch= approach to LLVM last year. At the time, they
> >> wanted freedom in their implementation and didn't want to be compatible
> >> with mine. Later they added GCC compatibility so that LLVM may be
> >> used to compile Linux kernel. I believe it will be the same case if this
> >> option is used to compile Linux kernel.
> >
> > Patch is OK then, thanks!
> >
>
> Checked into trunk. OK for backport to GCC 7 branch after a few days?
OK,
thanks!
Honza
>
>
> --
> H.J.
