Ensure slow properties for simple {__proto__:null} literals.

src/ast/compile-time-value.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ast/compile-time-value.h"
 
 #include "src/ast/ast.h"
 #include "src/factory.h"
 #include "src/handles-inl.h"
 #include "src/isolate.h"
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
 
 bool CompileTimeValue::IsCompileTimeValue(Expression* expression) {
   if (expression->IsLiteral()) return true;
   MaterializedLiteral* lit = expression->AsMaterializedLiteral();
   return lit != NULL && lit->is_simple();
 }
 
 Handle<FixedArray> CompileTimeValue::GetValue(Isolate* isolate,
                                               Expression* expression) {
   Factory* factory = isolate->factory();
   DCHECK(IsCompileTimeValue(expression));
   Handle<FixedArray> result = factory->NewFixedArray(2, TENURED);
-  ObjectLiteral* object_literal = expression->AsObjectLiteral();
-  if (object_literal != NULL) {
+  if (expression->IsObjectLiteral()) {
+    ObjectLiteral* object_literal = expression->AsObjectLiteral();
     DCHECK(object_literal->is_simple());
-    if (object_literal->fast_elements()) {
-      result->set(kLiteralTypeSlot, Smi::FromInt(OBJECT_LITERAL_FAST_ELEMENTS));
-    } else {
-      result->set(kLiteralTypeSlot, Smi::FromInt(OBJECT_LITERAL_SLOW_ELEMENTS));
-    }
+    result->set(kLiteralTypeSlot,
+                Smi::FromInt(object_literal->EncodeLiteralType()));
     result->set(kElementsSlot, *object_literal->constant_properties());
   } else {
     ArrayLiteral* array_literal = expression->AsArrayLiteral();
     DCHECK(array_literal != NULL && array_literal->is_simple());
-    result->set(kLiteralTypeSlot, Smi::FromInt(ARRAY_LITERAL));
+    result->set(kLiteralTypeSlot, Smi::FromInt(kArrayLiteralFlag));
     result->set(kElementsSlot, *array_literal->constant_elements());
   }
   return result;
 }
 
-CompileTimeValue::LiteralType CompileTimeValue::GetLiteralType(
-    Handle<FixedArray> value) {
-  Smi* literal_type = Smi::cast(value->get(kLiteralTypeSlot));
-  return static_cast<LiteralType>(literal_type->value());
+int CompileTimeValue::GetLiteralTypeFlags(Handle<FixedArray> value) {
+  return Smi::cast(value->get(kLiteralTypeSlot))->value();
 }
 
 Handle<HeapObject> CompileTimeValue::GetElements(Handle<FixedArray> value) {
   return Handle<HeapObject>(HeapObject::cast(value->get(kElementsSlot)));
 }
 
 }  // namespace internal
 }  // namespace v8