Extend locking of GCInfo table to include slot allocation.

Source/platform/heap/Visitor.h

Index: Source/platform/heap/Visitor.h
diff --git a/Source/platform/heap/Visitor.h b/Source/platform/heap/Visitor.h
index 587f0d6b3c3bf1aebe573743aee7b76be46ad482..989c35c31f6fdbfc2a7e0371193ee1ed857d9d11 100644
--- a/Source/platform/heap/Visitor.h
+++ b/Source/platform/heap/Visitor.h
@@ -863,7 +863,7 @@ extern PLATFORM_EXPORT GCInfo const** s_gcInfoTable;
 
 class GCInfoTable {
 public:
-    PLATFORM_EXPORT static size_t allocateGCInfoSlot();
+    PLATFORM_EXPORT static bool allocateGCInfoSlot(size_t&);
 
     static void init();
     static void shutdown();
@@ -872,7 +872,7 @@ public:
     static const size_t maxIndex = 1 << 15;
 
 private:
-    static void resize(size_t);
+    static void resize();
 
     static int s_gcInfoIndex;
     static size_t s_gcInfoTableSize;
@@ -880,12 +880,13 @@ private:
 
 // This macro should be used when returning a unique 15 bit integer
 // for a given gcInfo.
-#define RETURN_GCINFO_INDEX() \
-    static const size_t gcInfoIndex = GCInfoTable::allocateGCInfoSlot(); \
-    ASSERT(gcInfoIndex >= 1); \
-    ASSERT(gcInfoIndex < GCInfoTable::maxIndex);  \
-    ASSERT(s_gcInfoTable); \
-    s_gcInfoTable[gcInfoIndex] = &gcInfo; \
+#define RETURN_GCINFO_INDEX()                          \
+    static size_t gcInfoIndex = 0;                     \
+    ASSERT(s_gcInfoTable);                             \
+    if (!gcInfoIndex && GCInfoTable::allocateGCInfoSlot(gcInfoIndex)) \
+        s_gcInfoTable[gcInfoIndex] = &gcInfo;          \

[haraken, 2015/01/10 08:37:24]

Can we do this assignment in allocateGCInfoSlot? Probably we can rename it to
ensureGCInfoIndex or something.

[sof, 2015/01/10 08:42:46]

I suppose, but I don't see the overall benefit.

[haraken, 2015/01/10 08:48:45]

up to you :)

[sof, 2015/01/10 08:54:23]

Done.

+    ASSERT(gcInfoIndex >= 1);                          \
+    ASSERT(gcInfoIndex < GCInfoTable::maxIndex);       \
     return gcInfoIndex;
 
 template<typename T>