[all-commits] [llvm/llvm-project] 593681: ORC: Fix flaky OrcLazy tests

[Matt Arsenault via All-commits]

  Branch: refs/heads/users/arsenm/orc/lookup-init-symbols-notify-under-lock
  Home:   https://github.com/llvm/llvm-project
  Commit: 593681186a44360285299a1974384cbc38b0f7c0
      https://github.com/llvm/llvm-project/commit/593681186a44360285299a1974384cbc38b0f7c0
  Author: Matt Arsenault <Matthew.Arsenault at amd.com>
  Date:   2026-10-03 (Sat, 03 Oct 2026)

  Changed paths:
    M llvm/lib/ExecutionEngine/Orc/Core.cpp

  Log Message:
  -----------
  ORC: Fix flaky OrcLazy tests

I've seen this fail a few too many times so just let AI deal with it. I don't
know anything about orc, but extend lifetime of lock_guard seems plausible.

Notify lookupInitSymbols CV while holding the mutex

The init-symbol lookup completion callback decremented Count under
LookupMutex but called CV.notify_one() after releasing it. The waiting
thread could observe Count == 0, return from lookupInitSymbols, and
destroy the stack-allocated mutex and condition variable before the
callback signalled it. With concurrent compile threads the callback runs
on a dispatcher thread, so the late notify wrote into reused stack
memory, e.g. during endSession right after deinitialize.

This caused intermittent crashes in
ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll on macOS
(#50408, #126982). MachOPlatform and ELFNixPlatform already notify their
bootstrap condition variables under the mutex for the same reason.

Co-authored-by: Claude <noreply at anthropic.com>



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