[all-commits] [llvm/llvm-project] 8680d6: [mte] work around lifetime issue with setjmp.

[Florian Mayer via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 8680d6db1e45193bd3595f974fa2ef43bb85ca1e
      https://github.com/llvm/llvm-project/commit/8680d6db1e45193bd3595f974fa2ef43bb85ca1e
  Author: Florian Mayer <fmayer at google.com>
  Date:   2022-02-02 (Wed, 02 Feb 2022)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64StackTagging.cpp
    A llvm/test/CodeGen/AArch64/stack-tagging-setjmp.ll

  Log Message:
  -----------
  [mte] work around lifetime issue with setjmp.

setjmp can return twice, but PostDominatorTree is unaware of this. as
such, it overestimates postdominance, leaving some cases where memory
does not get untagged on return. this causes false positives later in
the program execution.

this is a workaround for now, in the longer term PostDominatorTree
should be made aware of returns_twice, as this may cause problems
elsewhere.

See D118647 for equivalent fix to HWASan.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D118749