[PATCH] D144470: [ARM] Remove redundant BTI instructions for table jumps

[Jirui Wu via Phabricator via llvm-commits]

JiruiWu created this revision.
JiruiWu added reviewers: olista01, chill, lenary.
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A BTI instruction was previously inserted at the beginning of each block
that has its address stored in a jump table. Jump tables only emit
indirect jumps in ARM or Thumb1 modes. However, PACBTI is not supported
in these modes. As a result, BTI instructions emitted by jump tables are
redundant. Removing redundant BTI instructions improves the code size
and prevents potential gadgets.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D144470

Files:
  llvm/lib/Target/ARM/ARMBranchTargets.cpp
  llvm/lib/Target/ARM/ARMConstantIslandPass.cpp
  llvm/test/CodeGen/Thumb2/bti-indirect-branches.ll
  llvm/test/CodeGen/Thumb2/bti-jump-table.mir
  llvm/test/MC/AArch64/remove-redundant-bti.s

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