[llvm-branch-commits] [llvm] [MTE] add stack frame history buffer (PR #86356)

[Florian Mayer via llvm-branch-commits]

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@@ -2497,7 +2497,8 @@ AArch64FrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
   return resolveFrameIndexReference(
       MF, FI, FrameReg,
       /*PreferFP=*/
-      MF.getFunction().hasFnAttribute(Attribute::SanitizeHWAddress),
+      MF.getFunction().hasFnAttribute(Attribute::SanitizeHWAddress) ||
+          MF.getFunction().hasFnAttribute(Attribute::SanitizeMemTag),
       /*ForSimm=*/false);
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fmayer wrote:

I don't think that makes a difference. I compiled a [moderately complicated file from AOSP](https://cs.android.com/android/platform/superproject/main/+/main:system/unwinding/libunwindstack/Unwinder.cpp) with memtag-stack and without this change (and with and without the `-stack-tagging-record-stack-history=instr`), and the assembly is the same.

The docstring "getFrameIndexReference - Provide a base+offset reference to an FI slot for debug info." also implies this shouldn't affect codegen.

https://github.com/llvm/llvm-project/pull/86356