[heap] Remove size specializations in static object visitors.

src/objects-body-descriptors-inl.h

Index: src/objects-body-descriptors-inl.h
diff --git a/src/objects-body-descriptors-inl.h b/src/objects-body-descriptors-inl.h
index d34c0f04e40a9e68bce0b75011441de7a7761209..ff679c984629063c6e1554ec680ad6d5848601f6 100644
--- a/src/objects-body-descriptors-inl.h
+++ b/src/objects-body-descriptors-inl.h
@@ -131,6 +131,31 @@ class JSObject::BodyDescriptor final : public BodyDescriptorBase {
   }
 };
 
+class JSObject::FastBodyDescriptor final : public BodyDescriptorBase {

[ulan, 2017/03/27 11:23:24]

This is the same as FlexibleBodyDescriptor except for SizeOf, which is much
faster here.

+ public:
+  static const int kStartOffset = JSReceiver::kPropertiesOffset;
+
+  static bool IsValidSlot(HeapObject* obj, int offset) {
+    return offset >= kStartOffset;
+  }
+
+  template <typename ObjectVisitor>
+  static inline void IterateBody(HeapObject* obj, int object_size,
+                                 ObjectVisitor* v) {
+    IteratePointers(obj, kStartOffset, object_size, v);
+  }
+
+  template <typename StaticVisitor>
+  static inline void IterateBody(HeapObject* obj, int object_size) {
+    Heap* heap = obj->GetHeap();
+    IteratePointers<StaticVisitor>(heap, obj, kStartOffset, object_size);
+  }
+
+  static inline int SizeOf(Map* map, HeapObject* object) {
+    return map->instance_size();
+  }
+};
+
 // Iterates the function object according to the visiting policy.
 template <JSFunction::BodyVisitingPolicy body_visiting_policy>
 class JSFunction::BodyDescriptorImpl final : public BodyDescriptorBase {