teach TSAN about SkSpinlock, SkRefCnt, and SkOnce

BUG=skia:
R=bsalomon@google.com, bungeman@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/247813005

git-svn-id: http://skia.googlecode.com/svn/trunk@14353 2bbb7eff-a529-9590-31e7-b0007b416f81

include/core/SkDynamicAnnotations.h

@@ -19,6 +19,10 @@ extern "C" {
 // TSAN provides these hooks.
 void AnnotateIgnoreReadsBegin(const char* file, int line);
 void AnnotateIgnoreReadsEnd(const char* file, int line);
+void AnnotateHappensBefore(const char* file, int line, const volatile void* ptr);
+void AnnotateHappensAfter(const char* file, int line, const volatile void* ptr);
+void AnnotateRWLockAcquired(const char* file, int line, const volatile void* lock, long is_w);
+void AnnotateRWLockReleased(const char* file, int line, const volatile void* lock, long is_w);
 }  // extern "C"
 
 // SK_ANNOTATE_UNPROTECTED_READ can wrap any variable read to tell TSAN to ignore that it appears to
@@ -37,9 +41,19 @@ inline T SK_ANNOTATE_UNPROTECTED_READ(const volatile T& x) {
     return read;
 }
 
+#define SK_ANNOTATE_HAPPENS_BEFORE(obj) AnnotateHappensBefore(__FILE__, __LINE__, obj)
+#define SK_ANNOTATE_HAPPENS_AFTER(obj)  AnnotateHappensAfter(__FILE__, __LINE__, obj)
+
+#define SK_ANNOTATE_RWLOCK_ACQUIRED(lock, w) AnnotateRWLockAcquired(__FILE__, __LINE__, lock, w)
+#define SK_ANNOTATE_RWLOCK_RELEASED(lock, w) AnnotateRWLockReleased(__FILE__, __LINE__, lock, w)
+
 #else  // !DYNAMIC_ANNOTATIONS_ENABLED
 
 #define SK_ANNOTATE_UNPROTECTED_READ(x) (x)
+#define SK_ANNOTATE_HAPPENS_BEFORE(obj)
+#define SK_ANNOTATE_HAPPENS_AFTER(obj)
+#define SK_ANNOTATE_RWLOCK_ACQUIRED(lock, w)
+#define SK_ANNOTATE_RWLOCK_RELEASED(lock, w)
 
 #endif
 

include/core/SkOnce.h

@@ -54,10 +54,12 @@ struct SkSpinlock {
         while (!sk_atomic_cas(&thisIsPrivate, 0, 1)) {
             // spin
         }
+        SK_ANNOTATE_RWLOCK_ACQUIRED(this, true);
     }
 
     void release() {
         SkASSERT(shouldBeZero == 0);
+        SK_ANNOTATE_RWLOCK_RELEASED(this, true);
         // This requires a release memory barrier before storing, which sk_atomic_cas guarantees.
         SkAssertResult(sk_atomic_cas(&thisIsPrivate, 1, 0));
     }
@@ -145,6 +147,7 @@ static void sk_once_slow(bool* done, Lock* lock, Func f, Arg arg, void (*atExit)
         // observable whenever we observe *done == true.
         release_barrier();
         *done = true;
+        SK_ANNOTATE_HAPPENS_BEFORE(done);
     }
 }
 
@@ -165,6 +168,7 @@ inline void SkOnce(bool* done, Lock* lock, Func f, Arg arg, void(*atExit)()) {
     // happens after f(arg), so by syncing to once->done = true here we're
     // forcing ourselves to also wait until the effects of f(arg) are readble.
     acquire_barrier();
+    SK_ANNOTATE_HAPPENS_AFTER(done);
 }
 
 template <typename Func, typename Arg>

include/core/SkRefCnt.h

@@ -37,7 +37,7 @@ public:
     */
     virtual ~SkRefCntBase() {
 #ifdef SK_DEBUG
-        SkASSERT(fRefCnt == 1);
+        SkASSERT(this->unique());
         fRefCnt = 0;    // illegal value, to catch us if we reuse after delete
 #endif
     }
@@ -53,6 +53,7 @@ public:
         // an unproctected read.  Generally, don't read fRefCnt, and don't stifle this warning.
         bool const unique = (1 == SK_ANNOTATE_UNPROTECTED_READ(fRefCnt));
         if (unique) {
+            SK_ANNOTATE_HAPPENS_AFTER(this);
             // Acquire barrier (L/SL), if not provided by load of fRefCnt.
             // Prevents user's 'unique' code from happening before decrements.
             //TODO: issue the barrier.
@@ -63,7 +64,7 @@ public:
     /** Increment the reference count. Must be balanced by a call to unref().
     */
     void ref() const {
-        SkASSERT(fRefCnt > 0);
+        SkASSERT(this->unsafeGetRefCnt() > 0);
         sk_atomic_inc(&fRefCnt);  // No barrier required.
     }
 
@@ -72,9 +73,11 @@ public:
         the object needs to have been allocated via new, and not on the stack.
     */
     void unref() const {
-        SkASSERT(fRefCnt > 0);
+        SkASSERT(this->unsafeGetRefCnt() > 0);
+        SK_ANNOTATE_HAPPENS_BEFORE(this);
         // Release barrier (SL/S), if not provided below.
         if (sk_atomic_dec(&fRefCnt) == 1) {
+            SK_ANNOTATE_HAPPENS_AFTER(this);
             // Acquire barrier (L/SL), if not provided above.
             // Prevents code in dispose from happening before the decrement.
             sk_membar_acquire__after_atomic_dec();
@@ -84,7 +87,7 @@ public:
 
 #ifdef SK_DEBUG
     void validate() const {
-        SkASSERT(fRefCnt > 0);
+        SkASSERT(this->unsafeGetRefCnt() > 0);
     }
 #endif
 
@@ -103,6 +106,9 @@ protected:
     }
 
 private:
+    // OK for use in asserts, but not much else.
+    int32_t unsafeGetRefCnt() { return SK_ANNOTATE_UNPROTECTED_READ(fRefCnt); }
+
     /**
      *  Called when the ref count goes to 0.
      */