[PATCH] D92906: [PowerPC] Restore stack ptr from frame ptr with setjmp

[Nemanja Ivanovic via Phabricator via llvm-commits]

nemanjai created this revision.
nemanjai added reviewers: vchuravy, hfinkel, PowerPC.
Herald added subscribers: shchenz, kbarton, hiraditya.
nemanjai requested review of this revision.
Herald added a project: LLVM.

If a function happens to:

- call `setjmp`
- do a 16-byte stack allocation
- call a function that sets up a stack frame and `longjmp`'s back

The stack pointer that is restores by `setjmp` will no longer point to a valid back chain. According to the ABI, stack accesses in such a function are to be frame pointer based - so it is an error (quite obviously) to restore the stack from the back chain.
We already restore the stack from the frame pointer when there are calls to `fast_cc` functions. We just need to also do that when there are calls to `setjmp`. This patch simply does that.

This was pointed out by the Julia team.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D92906

Files:
  llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
  llvm/test/CodeGen/PowerPC/stack-restore-with-setjmp.ll

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D92906.310409.patch
Type: text/x-patch
Size: 7878 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20201209/f5fd5d2f/attachment-0001.bin>