Optimize Map/Set.prototype.forEach

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index a56792c5f517c0c5b729c5fa7e47acc2cf50c559..ec2ec10230f5a74d1d1fc3286e49a230486bc15c 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -6966,6 +6966,36 @@ void FlexibleBodyDescriptor<start_offset>::IterateBody(HeapObject* obj,
 }
 
 
+template<class Derived, class TableType>
+Object* OrderedHashTableIterator<Derived, TableType>::CurrentKey() {
+  TableType* table(TableType::cast(this->table()));
+  int index = Smi::cast(this->index())->value();
+  Object* key = table->KeyAt(index);
+  ASSERT(!key->IsTheHole());
+  return key;
+}
+
+
+void JSSetIterator::PopulateValueArray(FixedArray* array) {
+  array->set(0, CurrentKey());
+}
+
+
+void JSMapIterator::PopulateValueArray(FixedArray* array) {
+  array->set(0, CurrentKey());
+  array->set(1, CurrentValue());
+}
+
+
+Object* JSMapIterator::CurrentValue() {
+  OrderedHashMap* table(OrderedHashMap::cast(this->table()));
+  int index = Smi::cast(this->index())->value();
+  Object* value = table->ValueAt(index);
+  ASSERT(!value->IsTheHole());
+  return value;
+}
+
+
 #undef TYPE_CHECKER
 #undef CAST_ACCESSOR
 #undef INT_ACCESSORS