[all-commits] [llvm/llvm-project] a74c7d: [win][aarch64] Always reserve frame pointers for A...

[Daniel Paoliello via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a74c7d877637f31ff25308969ef7ca6ed94aacc5
      https://github.com/llvm/llvm-project/commit/a74c7d877637f31ff25308969ef7ca6ed94aacc5
  Author: Daniel Paoliello <danpao at microsoft.com>
  Date:   2025-07-02 (Wed, 02 Jul 2025)

  Changed paths:
    M clang/lib/Driver/ToolChains/CommonArgs.cpp
    M clang/test/Driver/frame-pointer-elim.c
    M llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
    M llvm/lib/Target/AArch64/AArch64FrameLowering.h
    M llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp
    M llvm/test/CodeGen/AArch64/regress-w29-reserved-with-fp.ll
    M llvm/test/CodeGen/AArch64/win-sve.ll
    M llvm/test/CodeGen/AArch64/wincfi-missing-seh-directives.ll
    M llvm/test/CodeGen/AArch64/wineh-frame5.mir
    M llvm/test/CodeGen/AArch64/wineh-frame7.mir

  Log Message:
  -----------
  [win][aarch64] Always reserve frame pointers for Arm64 Windows (#146582)

There is no way in Arm64 Windows to indicate that a given function has
used the Frame Pointer as a General Purpose Register, as such stack
walks will always assume that the frame chain is valid and will follow
whatever value has been saved for the Frame Pointer (even if it is
pointing to data, etc.).

This change makes the Frame Pointer always reserved when building for
Arm64 Windows to avoid this issue.

We will be updating the official Windows ABI documentation to reflect
this requirement, and I will provide a link once it's available.



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