Index: compiler-rt/trunk/lib/tsan/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/lib/tsan/CMakeLists.txt
+++ compiler-rt/trunk/lib/tsan/CMakeLists.txt
@@ -47,6 +47,7 @@
 
 if(APPLE)
   list(APPEND TSAN_SOURCES
+    rtl/tsan_interceptors_mac.cc
     rtl/tsan_libdispatch_mac.cc
     rtl/tsan_platform_mac.cc
     rtl/tsan_platform_posix.cc)
Index: compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors_mac.cc
===================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors_mac.cc
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors_mac.cc
@@ -0,0 +1,91 @@
+//===-- tsan_interceptors_mac.cc ------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of ThreadSanitizer (TSan), a race detector.
+//
+// Mac-specific interceptors.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_platform.h"
+#if SANITIZER_MAC
+
+#include "interception/interception.h"
+#include "tsan_interceptors.h"
+
+#include <libkern/OSAtomic.h>
+
+namespace __tsan {
+
+TSAN_INTERCEPTOR(void, OSSpinLockLock, volatile OSSpinLock *lock) {
+  CHECK(!cur_thread()->is_dead);
+  if (!cur_thread()->is_inited) {
+    return REAL(OSSpinLockLock)(lock);
+  }
+  SCOPED_TSAN_INTERCEPTOR(OSSpinLockLock, lock);
+  REAL(OSSpinLockLock)(lock);
+  Acquire(thr, pc, (uptr)lock);
+}
+
+TSAN_INTERCEPTOR(bool, OSSpinLockTry, volatile OSSpinLock *lock) {
+  CHECK(!cur_thread()->is_dead);
+  if (!cur_thread()->is_inited) {
+    return REAL(OSSpinLockTry)(lock);
+  }
+  SCOPED_TSAN_INTERCEPTOR(OSSpinLockTry, lock);
+  bool result = REAL(OSSpinLockTry)(lock);
+  if (result)
+    Acquire(thr, pc, (uptr)lock);
+  return result;
+}
+
+TSAN_INTERCEPTOR(void, OSSpinLockUnlock, volatile OSSpinLock *lock) {
+  CHECK(!cur_thread()->is_dead);
+  if (!cur_thread()->is_inited) {
+    return REAL(OSSpinLockUnlock)(lock);
+  }
+  SCOPED_TSAN_INTERCEPTOR(OSSpinLockUnlock, lock);
+  Release(thr, pc, (uptr)lock);
+  REAL(OSSpinLockUnlock)(lock);
+}
+
+TSAN_INTERCEPTOR(void, os_lock_lock, void *lock) {
+  CHECK(!cur_thread()->is_dead);
+  if (!cur_thread()->is_inited) {
+    return REAL(os_lock_lock)(lock);
+  }
+  SCOPED_TSAN_INTERCEPTOR(os_lock_lock, lock);
+  REAL(os_lock_lock)(lock);
+  Acquire(thr, pc, (uptr)lock);
+}
+
+TSAN_INTERCEPTOR(bool, os_lock_trylock, void *lock) {
+  CHECK(!cur_thread()->is_dead);
+  if (!cur_thread()->is_inited) {
+    return REAL(os_lock_trylock)(lock);
+  }
+  SCOPED_TSAN_INTERCEPTOR(os_lock_trylock, lock);
+  bool result = REAL(os_lock_trylock)(lock);
+  if (result)
+    Acquire(thr, pc, (uptr)lock);
+  return result;
+}
+
+TSAN_INTERCEPTOR(void, os_lock_unlock, void *lock) {
+  CHECK(!cur_thread()->is_dead);
+  if (!cur_thread()->is_inited) {
+    return REAL(os_lock_unlock)(lock);
+  }
+  SCOPED_TSAN_INTERCEPTOR(os_lock_unlock, lock);
+  Release(thr, pc, (uptr)lock);
+  REAL(os_lock_unlock)(lock);
+}
+
+}  // namespace __tsan
+
+#endif  // SANITIZER_MAC
Index: compiler-rt/trunk/test/tsan/Darwin/osspinlock-norace.cc
===================================================================
--- compiler-rt/trunk/test/tsan/Darwin/osspinlock-norace.cc
+++ compiler-rt/trunk/test/tsan/Darwin/osspinlock-norace.cc
@@ -0,0 +1,30 @@
+// RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
+#include <libkern/OSAtomic.h>
+#include <pthread.h>
+#include <stdio.h>
+
+int Global;
+OSSpinLock lock;
+
+void *Thread(void *x) {
+  OSSpinLockLock(&lock);
+  Global++;
+  OSSpinLockUnlock(&lock);
+  return NULL;
+}
+
+int main() {
+  fprintf(stderr, "Hello world.\n");
+
+  pthread_t t[2];
+  pthread_create(&t[0], NULL, Thread, NULL);
+  pthread_create(&t[1], NULL, Thread, NULL);
+  pthread_join(t[0], NULL);
+  pthread_join(t[1], NULL);
+
+  fprintf(stderr, "Done.\n");
+}
+
+// CHECK: Hello world.
+// CHECK: Done.
+// CHECK-NOT: WARNING: ThreadSanitizer