[all-commits] [llvm/llvm-project] 0593ce: [MC] Add 'G' to augmentation string for MTE instru...

[Florian Mayer via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 0593ce5f0bbb7b9aebc5f15f60876b0bc7aad652
      https://github.com/llvm/llvm-project/commit/0593ce5f0bbb7b9aebc5f15f60876b0bc7aad652
  Author: Florian Mayer <fmayer at google.com>
  Date:   2022-06-08 (Wed, 08 Jun 2022)

  Changed paths:
    M llvm/include/llvm/MC/MCDwarf.h
    M llvm/include/llvm/MC/MCStreamer.h
    M llvm/lib/MC/MCAsmStreamer.cpp
    M llvm/lib/MC/MCDwarf.cpp
    M llvm/lib/MC/MCParser/AsmParser.cpp
    M llvm/lib/MC/MCStreamer.cpp
    M llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
    M llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
    M llvm/lib/Target/AArch64/AArch64InstrInfo.td
    M llvm/lib/Target/AArch64/AArch64MachineFunctionInfo.cpp
    M llvm/lib/Target/AArch64/AArch64MachineFunctionInfo.h
    M llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
    A llvm/test/CodeGen/AArch64/stack-tagging-cfi.ll

  Log Message:
  -----------
  [MC] Add 'G' to augmentation string for MTE instrumented functions

This was agreed on in
https://lists.llvm.org/pipermail/llvm-dev/2020-May/141345.html

The thread proposed two options
* add a character to augmentation string and handle in libuwind
* use a separate personality function.

It was determined that this is the simpler and better option.

This is part of ARM's Aarch64 ABI:
https://github.com/ARM-software/abi-aa/blob/main/aadwarf64/aadwarf64.rst#id22

The next step after this is teaching libunwind to untag when this
augmentation character is set.

Reviewed By: MaskRay, eugenis

Differential Revision: https://reviews.llvm.org/D127007