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

src/ast/compile-time-value.cc

Index: src/ast/compile-time-value.cc
diff --git a/src/ast/compile-time-value.cc b/src/ast/compile-time-value.cc
index 27dd29fee0a75af04e951f4f35e68fb1c46c63b2..b86343d059f223b11f88da62fddb3edb53d23a08 100644
--- a/src/ast/compile-time-value.cc
+++ b/src/ast/compile-time-value.cc
@@ -24,28 +24,24 @@ Handle<FixedArray> CompileTimeValue::GetValue(Isolate* isolate,
   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));
-    }
+    int literalTypeFlag = object_literal->EncodeLiteralType();
+    DCHECK_NE(kArrayLiteralFlag, literalTypeFlag);
+    result->set(kLiteralTypeSlot, Smi::FromInt(literalTypeFlag));
     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) {