Make leak counters thread-safe

include/core/SkInstCnt.h

Index: include/core/SkInstCnt.h
diff --git a/include/core/SkInstCnt.h b/include/core/SkInstCnt.h
index e38c42d917a41bc3bc0dcec1e9cf218f525f7828..be1b06ef7c7da73298df4c18d219fab5cadcee62 100644
--- a/include/core/SkInstCnt.h
+++ b/include/core/SkInstCnt.h
@@ -25,6 +25,8 @@
 
 extern bool gPrintInstCount;
 
+SkBaseMutex& SkGetInstCntAddInstChildMutex();
+
 // The non-root classes just register themselves with their parent
 #define SK_DECLARE_INST_COUNT(className)                                    \
     SK_DECLARE_INST_COUNT_INTERNAL(className,                               \
@@ -40,13 +42,14 @@ extern bool gPrintInstCount;
     public:                                                                 \
         typedef int (*PFCheckInstCnt)(int level, bool cleanUp);             \
         SkInstanceCountHelper() {                                           \
-            static bool gInited;                                            \
-            if (!gInited) {                                                 \
-                initStep                                                    \
-                GetChildren() = new SkTArray<PFCheckInstCnt>;               \
-                gInited = true;                                             \
+            if (0 == sk_atomic_inc(GetInstanceCountPtr())) {                \
+                sk_membar_aquire__after_atomic_dec();                       \
+                static bool gInited;                                        \

[bsalomon, 2013/12/04 15:04:19]

Perhaps we should use SK_DECLARE_STATIC_ONCE()/SkOnce() here.

[bungeman-skia, 2013/12/04 15:24:45]

Seconded.

[Kimmo Kinnunen, 2013/12/05 08:03:23]

Done.

+                if (!gInited) {                                             \
+                    initStep                                                \
+                    gInited = true;                                         \
+                }                                                           \
             }                                                               \
-            sk_atomic_inc(GetInstanceCountPtr());                           \
         }                                                                   \
                                                                             \
         SkInstanceCountHelper(const SkInstanceCountHelper&) {               \
@@ -105,8 +108,11 @@ extern bool gPrintInstCount;
     }                                                                       \
                                                                             \
     static void AddInstChild(int (*childCheckInstCnt)(int, bool)) {         \
-        if (CheckInstanceCount != childCheckInstCnt &&                      \
-            NULL != SkInstanceCountHelper::GetChildren()) {                 \
+        if (CheckInstanceCount != childCheckInstCnt) {                      \
+            SkAutoMutexAcquire ama(SkGetInstCntAddInstChildMutex());        \
+            if (NULL == SkInstanceCountHelper::GetChildren()) {             \

[robertphillips, 2013/12/04 14:01:22]

Why not use PFCheckInstCnt here?

[Kimmo Kinnunen, 2013/12/05 08:03:23]

I was confused with the previous need for separate _TEMPLATE macro, eg. I
assumed typename wouldn't work for non-templated classes. You're right, it
works. 
Done.

+                SkInstanceCountHelper::GetChildren() = new SkTArray<int (*)(int, bool)>; \
+            }                                                               \
             SkInstanceCountHelper::GetChildren()->push_back(childCheckInstCnt); \
         }                                                                   \
     }