[all-commits] [llvm/llvm-project] dfec26: Thread safety analysis: Don't warn about managed l...

[Aaron Puchert via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: dfec26b186d2f0c80f2b70901b7cc5747f5b377c
      https://github.com/llvm/llvm-project/commit/dfec26b186d2f0c80f2b70901b7cc5747f5b377c
  Author: Aaron Puchert <aaron.puchert at sap.com>
  Date:   2021-04-06 (Tue, 06 Apr 2021)

  Changed paths:
    M clang/lib/Analysis/ThreadSafety.cpp
    M clang/test/SemaCXX/warn-thread-safety-analysis.cpp

  Log Message:
  -----------
  Thread safety analysis: Don't warn about managed locks on join points

We already did so for scoped locks acquired in the constructor, this
change extends the treatment to deferred locks and scoped unlocking, so
locks acquired outside of the constructor. Obviously this makes things
more consistent.

Originally I thought this was a bad idea, because obviously it
introduces false negatives when it comes to double locking, but these
are typically easily found in tests, and the primary goal of the Thread
safety analysis is not to find double locks but race conditions.
Since the scoped lock will release the mutex anyway when the scope ends,
the inconsistent state is just temporary and probably fine.

Reviewed By: delesley

Differential Revision: https://reviews.llvm.org/D98747