libsanitizer merge from upstream r173241

From-SVN: r195404

1 files changed, 16 insertions, 1 deletions

diff --git a/libsanitizer/sanitizer_common/sanitizer_mutex.h b/libsanitizer/sanitizer_common/sanitizer_mutex.h
index a38a49ae242..27009118e62 100644
--- a/libsanitizer/sanitizer_common/sanitizer_mutex.h
+++ b/libsanitizer/sanitizer_common/sanitizer_mutex.h
@@ -25,11 +25,15 @@ class StaticSpinMutex {
   }
 
   void Lock() {
-    if (atomic_exchange(&state_, 1, memory_order_acquire) == 0)
+    if (TryLock())
       return;
     LockSlow();
   }
 
+  bool TryLock() {
+    return atomic_exchange(&state_, 1, memory_order_acquire) == 0;
+  }
+
   void Unlock() {
     atomic_store(&state_, 0, memory_order_release);
   }
@@ -61,6 +65,16 @@ class SpinMutex : public StaticSpinMutex {
   void operator=(const SpinMutex&);
 };
 
+class BlockingMutex {
+ public:
+  explicit BlockingMutex(LinkerInitialized);
+  void Lock();
+  void Unlock();
+ private:
+  uptr opaque_storage_[10];
+  uptr owner_;  // for debugging
+};
+
 template<typename MutexType>
 class GenericScopedLock {
  public:
@@ -100,6 +114,7 @@ class GenericScopedReadLock {
 };
 
 typedef GenericScopedLock<StaticSpinMutex> SpinMutexLock;
+typedef GenericScopedLock<BlockingMutex> BlockingMutexLock;
 
 }  // namespace __sanitizer