[Bug target/94891] aarch64: there is no way to strip PAC from a return address in c code

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94891

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Szabolcs Nagy <n...@gcc.gnu.org>:

https://gcc.gnu.org/g:a70d5d81c41048556fd86eaa1036018a6bfba115

commit r9-8744-ga70d5d81c41048556fd86eaa1036018a6bfba115
Author: Szabolcs Nagy <szabolcs.n...@arm.com>
Date:   Tue Jun 2 16:44:41 2020 +0100

    aarch64: fix return address access with pac [PR94891][PR94791]

    This is a big hammer fix for __builtin_return_address (PR target/94891)
    returning signed addresses (sometimes, depending on wether lr happens
    to be signed or not at the time of call which depends on optimizations),
    and similarly -pg may pass signed return address to _mcount
    (PR target/94791).

    At the time of return address expansion we don't know if it's signed or
    not so it is done unconditionally.

    2020-07-13  Szabolcs Nagy  <szabolcs.n...@arm.com>

    gcc/ChangeLog:

            PR target/94891
            PR target/94791
            * config/aarch64/aarch64-protos.h (aarch64_return_addr_rtx):
Declare.
            * config/aarch64/aarch64.c (aarch64_return_addr_rtx): New.
            (aarch64_return_addr): Use aarch64_return_addr_rtx.
            * config/aarch64/aarch64.h (PROFILE_HOOK): Likewise.

    (cherry picked from commit 463a54e5d4956143f81c1f23b91cbd2d93855741)