[all-commits] [llvm/llvm-project] c12c7a: [ARM] add common parts for PACBTI-M support in the...

[Ties Stuij via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c12c7a84b03b98445ca9011ccbce12030c7b72e3
      https://github.com/llvm/llvm-project/commit/c12c7a84b03b98445ca9011ccbce12030c7b72e3
  Author: Ties Stuij <ties.stuij at arm.com>
  Date:   2021-12-01 (Wed, 01 Dec 2021)

  Changed paths:
    M llvm/lib/Target/ARM/ARMMachineFunctionInfo.cpp
    M llvm/lib/Target/ARM/ARMMachineFunctionInfo.h

  Log Message:
  -----------
  [ARM] add common parts for PACBTI-M support in the backend

This patch encapsulates decision logic about when and how to generate
PAC/BTI related code. It's a part shared by PAC-RET, BTI placement,
build attribute emission, etc, so it make sense committing it
separately in order to unblock the aforementioned parts, which can
proceed concurrently.

This patch adds a few member functions to `ARMFunctionInfo`, which are currently
unused, therefore there is no testing for them at the moment. This code is
tested in follow-up PAC/BTI code gen patches.

This patch is part of a series that adds support for the PACBTI-M extension of
the Armv8.1-M architecture, as detailed here:

https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension

The PACBTI-M specification can be found in the Armv8-M Architecture Reference
Manual:

https://developer.arm.com/documentation/ddi0553/latest

The following people contributed to this patch:

- Momchil Velikov
- Ties Stuij

Reviewed By: danielkiss

Differential Revision: https://reviews.llvm.org/D112423