Add support for calling TSan's acquire()/release()

Author: Julian Lettner

stdlib/public/Concurrency/CMakeLists.txt

@@ -65,6 +65,7 @@ add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} I
   TaskGroup.swift
   TaskLocal.cpp
   TaskLocal.swift
+  ThreadSanitizer.cpp
   Mutex.cpp
   ${swift_concurrency_objc_sources}
 

stdlib/public/Concurrency/TaskPrivate.h

@@ -56,6 +56,11 @@ void donateThreadToGlobalExecutorUntil(bool (*condition)(void*),
                                        void *context);
 #endif
 
+/// release() establishes a happens-before relation with a preceding acquire()
+/// on the same address.
+void _swift_tsan_acquire(void *addr);
+void _swift_tsan_release(void *addr);
+
 // ==== ------------------------------------------------------------------------
 // TODO: this was moved from Task.cpp to share it with TaskGroup.cpp, where else better place to put it?
 

stdlib/public/Concurrency/ThreadSanitizer.cpp

@@ -0,0 +1,35 @@
+//===--- ThreadSanitizer.cpp - Thread Sanitizer support -------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// Thread Sanitizer support for the Swift Task runtime
+//
+//===----------------------------------------------------------------------===//
+
+#include "TaskPrivate.h"
+
+#include <dlfcn.h>
+
+using TSanFunc = void(void *);
+
+void swift::_swift_tsan_acquire(void *addr) {
+  static auto ptr = (TSanFunc *)dlsym(RTLD_DEFAULT, "__tsan_acquire");
+  if (ptr) {
+    ptr(addr);
+  }
+}
+
+void swift::_swift_tsan_release(void *addr) {
+  static auto ptr = (TSanFunc *)dlsym(RTLD_DEFAULT, "__tsan_release");
+  if (ptr) {
+    ptr(addr);
+  }
+}