Fix usage of literal cloning for large double arrays.

src/ast/ast.cc

Index: src/ast/ast.cc
diff --git a/src/ast/ast.cc b/src/ast/ast.cc
index d847f5449eecc2c300fdfea382a3ae67eb2332e1..fbc70c2abfaacf171fcea5b67b7c40beb7fa71b7 100644
--- a/src/ast/ast.cc
+++ b/src/ast/ast.cc
@@ -574,6 +574,14 @@ void ObjectLiteral::BuildConstantProperties(Isolate* isolate) {
   set_depth(depth_acc);
 }
 
+bool ObjectLiteral::IsFastCloningSupported() const {
+  // FastCloneShallowObjectStub doesn't copy elements, and object literals don't
+  // support copy-on-write (COW) elements for now.
+  // TODO(mvstanton): make object literals support COW elements.
+  return fast_elements() && has_shallow_properties() &&
+         properties_count() <=
+             FastCloneShallowObjectStub::kMaximumClonedProperties;
+}
 
 void ArrayLiteral::BuildConstantElements(Isolate* isolate) {
   DCHECK_LT(first_spread_index_, 0);
@@ -648,6 +656,11 @@ void ArrayLiteral::BuildConstantElements(Isolate* isolate) {
   set_depth(depth_acc);
 }
 
+bool ArrayLiteral::IsFastCloningSupported() const {
+  return depth() <= 1 &&
+         values()->length() <=
+             FastCloneShallowArrayStub::kMaximumClonedElements;
+}
 
 void ArrayLiteral::AssignFeedbackVectorSlots(Isolate* isolate,
                                              FeedbackVectorSpec* spec,