[NotForCommit] inline ensureMarked.

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 94ca56442140c3618c1db43b080493208ec21f04..8da1800bbc9efd09a245f42671e3e5f97b1c29a2 100644
--- a/Source/platform/heap/Visitor.h
+++ b/Source/platform/heap/Visitor.h
@@ -191,7 +191,7 @@ template<typename T> class TraceTrait<const T> : public TraceTrait<T> { };
 // be eagerly traced by default. A class type can opt out by declaring
 // a TraceEagerlyTrait<> specialization, mapping the value to 'false'
 // (see the WILL_NOT_BE_EAGERLY_TRACED() macro below.)
-#define ENABLE_EAGER_TRACING_BY_DEFAULT 0
+#define ENABLE_EAGER_TRACING_BY_DEFAULT 1
 
 // DISABLE_ALL_EAGER_TRACING provides the "kill switch" for eager
 // tracing; setting it to 1 will disable the use of eager tracing
@@ -264,6 +264,11 @@ struct ObjectAliveTrait {
     static bool isHeapObjectAlive(Visitor*, T*);
 };
 
+enum MarkingMode {
+    GlobalMarking,
+    ThreadLocalMarking,
+};
+
 // Visitor is used to traverse the Blink object graph. Used for the
 // marking phase of the mark-sweep garbage collector.
 //
@@ -275,6 +280,7 @@ struct ObjectAliveTrait {
 // contained pointers and push them on the marking stack.
 class PLATFORM_EXPORT Visitor {
 public:
+    Visitor(MarkingMode mode) : m_mode(mode) {}
     virtual ~Visitor() { }
 
     template<typename T>
@@ -465,7 +471,8 @@ public:
 #endif
 
     virtual bool isMarked(const void*) = 0;
-    virtual bool ensureMarked(const void*) = 0;
+
+    bool ensureMarked(const void*);
 
     template<typename T> inline bool isAlive(T* obj)
     {
@@ -497,8 +504,8 @@ public:
 #define DECLARE_VISITOR_METHODS(Type)                            \
     DEBUG_ONLY(void checkGCInfo(const Type*, const GCInfo*);)    \
     virtual void mark(const Type*, TraceCallback) = 0;           \
-    virtual bool isMarked(const Type*) = 0;                      \
-    virtual bool ensureMarked(const Type*) = 0;
+    virtual bool isMarked(const Type*) = 0; \
+    bool ensureMarked(const Type*);
 
     FOR_EACH_TYPED_HEAP(DECLARE_VISITOR_METHODS)
 #undef DECLARE_VISITOR_METHODS
@@ -511,16 +518,7 @@ public:
     }
 #endif
 
-    inline bool canTraceEagerly() const { return m_traceDepth < kMaxEagerTraceDepth; }
-    inline void incrementTraceDepth() { m_traceDepth++; }
-    inline void decrementTraceDepth() { ASSERT(m_traceDepth > 0); m_traceDepth--; }
-
 protected:
-    Visitor()
-        : m_traceDepth(0)
-    {
-    }
-
     virtual void registerWeakCell(void**, WeakPointerCallback) = 0;
 #if ENABLE(GC_PROFILE_MARKING)
     void* m_hostObject;
@@ -536,11 +534,7 @@ private:
             *cell = 0;
     }
 
-    // The maximum depth of eager, unrolled trace() calls that is
-    // considered safe and allowed.
-    const int kMaxEagerTraceDepth = 100;
-
-    int m_traceDepth;
+    MarkingMode m_mode;
 };
 
 // We trace vectors by using the trace trait on each element, which means you
@@ -594,21 +588,9 @@ public:
         // If the trait allows it, invoke the trace callback right here on the
         // not-yet-marked object.
         if (!DISABLE_ALL_EAGER_TRACING && TraceEagerlyTrait<T>::value) {
-            // Protect against too deep trace call chains, and the
-            // unbounded system stack usage they can bring about.
-            //
-            // Assert against deep stacks so as to flush them out,
-            // but test and appropriately handle them should they occur
-            // in release builds.
-            ASSERT(visitor->canTraceEagerly());
-            if (LIKELY(visitor->canTraceEagerly())) {
-                if (visitor->ensureMarked(t)) {
-                    visitor->incrementTraceDepth();
-                    TraceTrait<T>::trace(visitor, const_cast<T*>(t));
-                    visitor->decrementTraceDepth();
-                }
-                return;
-            }
+            if (visitor->ensureMarked(t))
+                TraceTrait<T>::trace(visitor, const_cast<T*>(t));
+            return;
         }
         visitor->mark(const_cast<T*>(t), &TraceTrait<T>::trace);
     }