Implement Visitor::isGlobalMarkingVisitor

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 f0b9ed70b31598dee872e40a39293c0055631ad8..c4fe24d4d405ab1584cace4edd7d812abcb4c107 100644
--- a/Source/platform/heap/Visitor.h
+++ b/Source/platform/heap/Visitor.h
@@ -264,6 +264,11 @@ struct ObjectAliveTrait {
 // contained pointers and push them on the marking stack.
 class PLATFORM_EXPORT Visitor {
 public:
+    enum VisitorType {
+        GlobalMarkingVisitorType,
+        GenericVisitorType,
+    };
+
     virtual ~Visitor() { }
 
     // One-argument templated mark method. This uses the static type of
@@ -531,9 +536,12 @@ public:
     inline void incrementTraceDepth() { m_traceDepth++; }
     inline void decrementTraceDepth() { ASSERT(m_traceDepth > 0); m_traceDepth--; }
 
+    inline bool isGlobalMarkingVisitor() const { return m_isGlobalMarkingVisitor; }
+
 protected:
-    Visitor()
+    Visitor(VisitorType type)

[haraken, 2014/12/16 06:53:30]

Add explicit

[kouhei (in TOK), 2014/12/16 06:58:27]

Done.

         : m_traceDepth(0)
+        , m_isGlobalMarkingVisitor(type == GlobalMarkingVisitorType)
     {
     }
 
@@ -557,6 +565,7 @@ private:
     const int kMaxEagerTraceDepth = 100;
 
     int m_traceDepth;
+    bool m_isGlobalMarkingVisitor;

[haraken, 2014/12/16 06:53:29]

Can we store m_visitorType, instead of m_isGlobalMarkingVisitor?

[kouhei (in TOK), 2014/12/16 06:58:27]

"type == GlobalMarkingVisitorType" is slower than m_isGlobalMarkingVisitor, so
I'd prefer just a bool here, but it might be a premature optimization.

 };
 
 // We trace vectors by using the trace trait on each element, which means you