[all-commits] [llvm/llvm-project] 636428: tsan: unify __cxa_guard_acquire and pthread_once i...

[Dmitry Vyukov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 636428c727cdcfe37b8e950e32d10f06fa4f5dfa
      https://github.com/llvm/llvm-project/commit/636428c727cdcfe37b8e950e32d10f06fa4f5dfa
  Author: Dmitry Vyukov <dvyukov at google.com>
  Date:   2021-08-04 (Wed, 04 Aug 2021)

  Changed paths:
    M compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp

  Log Message:
  -----------
  tsan: unify __cxa_guard_acquire and pthread_once implementations

Currently we effectively duplicate "once" logic for __cxa_guard_acquire
and pthread_once. Unify the implementations.

This is not a no-op change:
 - constants used for pthread_once are changed to match __cxa_guard_acquire
   (__cxa_guard_acquire constants are tied to ABI, but it does not seem
   to be the case for pthread_once)
 - pthread_once now also uses PotentiallyBlockingRegion annotations
 - __cxa_guard_acquire checks thr->in_ignored_lib to skip user synchronization
It's unclear if these 2 differences are intentional or a mere sloppy inconsistency.
Since all tests still pass, let's assume the latter.

Reviewed By: vitalybuka, melver

Differential Revision: https://reviews.llvm.org/D107359