TSAN: use somewhat pithier SK_ANNOTATE_UNPROTECTED_READ.

include/core/SkRefCnt.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkRefCnt_DEFINED
 #define SkRefCnt_DEFINED
 
+#include "SkDynamicAnnotations.h"
 #include "SkThread.h"
 #include "SkInstCnt.h"
 #include "SkTemplates.h"
 
 /** \class SkRefCntBase
 
     SkRefCntBase is the base class for objects that may be shared by multiple
     objects. When an existing owner wants to share a reference, it calls ref().
     When an owner wants to release its reference, it calls unref(). When the
     shared object's reference count goes to zero as the result of an unref()
@@ skipping 14 matching lines @@
     virtual ~SkRefCntBase() {
 #ifdef SK_DEBUG
         SkASSERT(fRefCnt == 1);
         fRefCnt = 0;    // illegal value, to catch us if we reuse after delete
 #endif
     }
 
     /** Return the reference count. Use only for debugging. */
     int32_t getRefCnt() const { return fRefCnt; }
 
-    /** Returns true if the caller is the only owner.
+    /** May return true if the caller is the only owner.
      *  Ensures that all previous owner's actions are complete.
      */
     bool unique() const {
-        bool const unique = (1 == fRefCnt);
+        // We believe we're reading fRefCnt in a safe way here, so we stifle the TSAN warning about
+        // an unproctected read.  Generally, don't read fRefCnt, and don't stifle this warning.

[bungeman-skia, 2014/02/04 17:21:39]

nit: two spaces after the period.

+        bool const unique = (1 == SK_ANNOTATE_UNPROTECTED_READ(fRefCnt));
         if (unique) {
             // Acquire barrier (L/SL), if not provided by load of fRefCnt.
             // Prevents user's 'unique' code from happening before decrements.
             //TODO: issue the barrier.
         }
         return unique;
     }
 
     /** Increment the reference count. Must be balanced by a call to unref().
     */
@@ skipping 218 matching lines @@
     typedef T* SkRefPtr::*unspecified_bool_type;
     operator unspecified_bool_type() const {
         return fObj ? &SkRefPtr::fObj : NULL;
     }
 
 private:
     T* fObj;
 };
 
 #endif