Import compiler-rt r160957.

1 files changed, 100 insertions, 0 deletions

diff --git a/lib/sanitizer_common/sanitizer_mutex.h b/lib/sanitizer_common/sanitizer_mutex.h
new file mode 100644
index 0000000..ca3e2f9
--- /dev/null
+++ b/lib/sanitizer_common/sanitizer_mutex.h
@@ -0,0 +1,100 @@
+//===-- sanitizer_mutex.h ---------------------------------------*- C++ -*-===//
+//
+//                     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/AddressSanitizer runtime.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SANITIZER_MUTEX_H
+#define SANITIZER_MUTEX_H
+
+#include "sanitizer_atomic.h"
+#include "sanitizer_internal_defs.h"
+#include "sanitizer_libc.h"
+
+namespace __sanitizer {
+
+class SpinMutex {
+ public:
+  SpinMutex() {
+    atomic_store(&state_, 0, memory_order_relaxed);
+  }
+
+  void Lock() {
+    if (atomic_exchange(&state_, 1, memory_order_acquire) == 0)
+      return;
+    LockSlow();
+  }
+
+  void Unlock() {
+    atomic_store(&state_, 0, memory_order_release);
+  }
+
+ private:
+  atomic_uint8_t state_;
+
+  void NOINLINE LockSlow() {
+    for (int i = 0;; i++) {
+      if (i < 10)
+        proc_yield(10);
+      else
+        internal_sched_yield();
+      if (atomic_load(&state_, memory_order_relaxed) == 0
+          && atomic_exchange(&state_, 1, memory_order_acquire) == 0)
+        return;
+    }
+  }
+
+  SpinMutex(const SpinMutex&);
+  void operator=(const SpinMutex&);
+};
+
+template<typename MutexType>
+class GenericScopedLock {
+ public:
+  explicit GenericScopedLock(MutexType *mu)
+      : mu_(mu) {
+    mu_->Lock();
+  }
+
+  ~GenericScopedLock() {
+    mu_->Unlock();
+  }
+
+ private:
+  MutexType *mu_;
+
+  GenericScopedLock(const GenericScopedLock&);
+  void operator=(const GenericScopedLock&);
+};
+
+template<typename MutexType>
+class GenericScopedReadLock {
+ public:
+  explicit GenericScopedReadLock(MutexType *mu)
+      : mu_(mu) {
+    mu_->ReadLock();
+  }
+
+  ~GenericScopedReadLock() {
+    mu_->ReadUnlock();
+  }
+
+ private:
+  MutexType *mu_;
+
+  GenericScopedReadLock(const GenericScopedReadLock&);
+  void operator=(const GenericScopedReadLock&);
+};
+
+typedef GenericScopedLock<SpinMutex> SpinMutexLock;
+
+}  // namespace __sanitizer
+
+#endif  // SANITIZER_MUTEX_H