Whitelist intentionally racy TRACE_EVENT reads and writes.

src/core/SkTraceEvent.h

 // Copyright (c) 2014 Google Inc.
 //
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This header file defines the set of trace_event macros without specifying
 // how the events actually get collected and stored. If you need to expose trace
 // events to some other universe, you can copy-and-paste this file as well as
 // trace_event.h, modifying the macros contained there as necessary for the
 // target platform. The end result is that multiple libraries can funnel events
@@ skipping 144 matching lines @@
 // again under lock.
 //
 // Without the use of these static category pointers and enabled flags all
 // trace points would carry a significant performance cost of acquiring a lock
 // and resolving the category.
 
 #ifndef SkTraceEvent_DEFINED
 #define SkTraceEvent_DEFINED
 
 #include "SkEventTracer.h"
+#include "SkDynamicAnnotations.h"
 
 // By default, const char* argument values are assumed to have long-lived scope
 // and will not be copied. Use this macro to force a const char* to be copied.
 #define TRACE_STR_COPY(str) \
     skia::tracing_internals::TraceStringWithCopy(str)
 
 // By default, uint64 ID argument values are not mangled with the Process ID in
 // TRACE_EVENT_ASYNC macros. Use this macro to force Process ID mangling.
 #define TRACE_ID_MANGLE(id) \
     skia::tracing_internals::TraceID::ForceMangle(id)
@@ skipping 582 matching lines @@
 //     const char* name,
 //     SkEventTracer::Handle id)
 #define TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION \
     SkEventTracer::GetInstance()->updateTraceEventDuration
 
 // These operations are atomic in the Chrome tracing implementation
 // to cater to ARM's weak memory consistency; we're just doing read/
 // write here because it's not strictly needed for correctness.
 // So says Nat.
 // FIXME
+//
+// Skia addition: we mark these as unprotected reads and writes to shut up TSAN.
 
 #define TRACE_EVENT_API_ATOMIC_WORD intptr_t
-#define TRACE_EVENT_API_ATOMIC_LOAD(var) (*(&var))
-#define TRACE_EVENT_API_ATOMIC_STORE(var, value) (var=value)
+#define TRACE_EVENT_API_ATOMIC_LOAD(var) SK_ANNOTATE_UNPROTECTED_READ(var)
+#define TRACE_EVENT_API_ATOMIC_STORE(var, value) SK_ANNOTATE_UNPROTECTED_WRITE(&var, value)
 
 // Defines visibility for classes in trace_event.h
 #define TRACE_EVENT_API_CLASS_EXPORT SK_API
 
 // The thread buckets for the sampling profiler.
 TRACE_EVENT_API_CLASS_EXPORT extern \
     TRACE_EVENT_API_ATOMIC_WORD g_trace_state[3];
 
 #define TRACE_EVENT_API_THREAD_BUCKET(thread_bucket)                           \
     g_trace_state[thread_bucket]
@@ skipping 455 matching lines @@
   }
 
  private:
   const char* previous_state_;
 };
 
 }  // namespace tracing_internals
 }  // namespace skia
 
 #endif