[all-commits] [llvm/llvm-project] 4dc462: [AArch64] Emit CFI instruction for updating x18 wh...

[PiJoules via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4dc462b58909a73a2ae219863f4b7219483ba23e
      https://github.com/llvm/llvm-project/commit/4dc462b58909a73a2ae219863f4b7219483ba23e
  Author: Leonard Chan <leonardchan at google.com>
  Date:   2021-10-08 (Fri, 08 Oct 2021)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
    M llvm/test/CodeGen/AArch64/shadow-call-stack.ll

  Log Message:
  -----------
  [AArch64] Emit CFI instruction for updating x18 when using ShadowCallStack with exception unwinding

PR45875 notes an instance where exception handling crashes on aarch64-fuchsia
where SCS is enabled by default. The underlying issue seems to be that within libunwind,
various _Unwind_* functions, the x18 register is not updated if a function is marked
with nounwind. This removes the check for nounwind and emits the CFI instruction that updates x18.

Differential Revision: https://reviews.llvm.org/D79822