commit 6a4c0551fbd905397666676142d59af81585c2cb
author Tobias Hieta <tobias@plex.tv> Fri Aug 05 21:44:56 2022 +0200
committer Copybara-Service <copybara-worker@google.com> Fri Aug 05 12:52:28 2022 -0700
tree bee05029455fa2b408e00119272848121bb7c8e9
parent e87e9b82b5fed9bf7860584bf29c679614edf319

[llvm][macos] Fix usage of std::shared_mutex on old macOS SDK versions

When setting CMAKE_CXX_STANDARD to 17 and targeting a macOS version
under 10.12 the ifdefs would try to use std::shared_mutex because
the of the C++ standard. This should also check the targeted SDK.

See discussion in: https://reviews.llvm.org/D130689

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D131063

GitOrigin-RevId: 4b8db17c32e04a1fe17440a6fb80aa96f31ff068

include/llvm/Support/RWMutex.h

diff --git a/include/llvm/Support/RWMutex.h b/include/llvm/Support/RWMutex.h
index 3dd9625..a06a5c3 100644
--- a/include/llvm/Support/RWMutex.h
+++ b/include/llvm/Support/RWMutex.h
@@ -94,15 +94,15 @@
 template <bool mt_only> class SmartRWMutex {
   // shared_mutex (C++17) is more efficient than shared_timed_mutex (C++14)
   // on Windows and always available on MSVC except with libc++.
+#if !defined(LLVM_USE_RW_MUTEX_IMPL)
 #if (defined(_MSC_VER) && !defined(_LIBCPP_VERSION)) || __cplusplus > 201402L
   std::shared_mutex impl;
 #else
-#if !defined(LLVM_USE_RW_MUTEX_IMPL)
   std::shared_timed_mutex impl;
+#endif
 #else
   RWMutexImpl impl;
 #endif
-#endif
   unsigned readers = 0;
   unsigned writers = 0;