Add SkBarriers_tsan.h.

src/ports/SkBarriers_tsan.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkBarriers_tsan_DEFINED
+#define SkBarriers_tsan_DEFINED
+
+#include <sanitizer/tsan_interface_atomic.h>
+
+static inline void sk_compiler_barrier() { asm volatile("" : : : "memory"); }
+
+// We'd do this as separate functions, but you can't partially specialize functions...
+template <typename T, size_t bits>
+struct SkBarriers {
+    static T AcquireLoad(T*);
+    static void ReleaseStore(T*, T);
+};
+
+#define SK_BARRIERS(BITS)                                                          \
+    template <typename T>                                                          \
+    struct SkBarriers<T, BITS> {                                                   \
+        static T AcquireLoad(T* ptr) {                                             \
+            return (T)__tsan_atomic ## BITS ## _load((__tsan_atomic ## BITS*)ptr,  \
+                                                     __tsan_memory_order_acquire); \
+        }                                                                          \
+        static void ReleaseStore(T* ptr, T val) {                                  \
+            __tsan_atomic ## BITS ## _store((__tsan_atomic ## BITS*)ptr,           \
+                                            val,                                   \
+                                            __tsan_memory_order_release);          \
+        }                                                                          \
+    }
+SK_BARRIERS(8);
+SK_BARRIERS(16);
+SK_BARRIERS(32);
+SK_BARRIERS(64);
+#undef SK_BARRIERS
+
+template <typename T>
+T sk_acquire_load(T* ptr) { return SkBarriers<T, 8*sizeof(T)>::AcquireLoad(ptr); }
+
+template <typename T>
+void sk_release_store(T* ptr, T val) { SkBarriers<T, 8*sizeof(T)>::ReleaseStore(ptr, val); }
+
+
+#endif//SkBarriers_tsan_DEFINED