[all-commits] [llvm/llvm-project] a8f36c: [AArch64] Check Subtarget via STI in getInstSizeIn...

[Zachary Yedidia via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a8f36ccb2a24ef4abcbff58b2f36ce2deacefd54
      https://github.com/llvm/llvm-project/commit/a8f36ccb2a24ef4abcbff58b2f36ce2deacefd54
  Author: Zachary Yedidia <zyedidia at gmail.com>
  Date:   2026-04-14 (Tue, 14 Apr 2026)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64InstrInfo.cpp

  Log Message:
  -----------
  [AArch64] Check Subtarget via STI in getInstSizeInBytes (#192089)

The InstSizes test (`llvm/unittests/Target/AArch64/InstSizes.cpp`)
destroys the Subtarget field early (`ST` created on the stack in
[`createInstrInfo`](https://github.com/llvm/llvm-project/blob/40a585e742ed6b28306d7511380079325ba1a003/llvm/unittests/Target/AArch64/InstSizes.cpp#L32)),
causing a use-after-free if it is used in `getInstSizeInBytes`. This
causes a failure when running the test with hwasan (reported by build
bot). To fix this, this PR switches to using `STI` instead of
`Subtarget` in `getInstSizeInBytes` for checking `isLFI`, which survives
for the lifetime of the test.

I think fixing the test itself (the root of the issue, as far as I can
tell) would be more involved. Perhaps I should open an issue for it
though?

I have tested the fix on an AArch64 machine with hwasan to confirm that
it resolves the issue.



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