Use generic representation when normalizing boilerplate properties

src/runtime.cc

 // Copyright 2012 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 <stdlib.h>
 #include <limits>
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
@@ skipping 227 matching lines @@
   Handle<JSObject> boilerplate =
       isolate->factory()->NewJSObjectFromMap(map, pretenure_flag);
 
   // Normalize the elements of the boilerplate to save space if needed.
   if (!should_have_fast_elements) JSObject::NormalizeElements(boilerplate);
 
   // Add the constant properties to the boilerplate.
   int length = constant_properties->length();
   bool should_transform =
       !is_result_from_cache && boilerplate->HasFastProperties();
-  if (should_transform || has_function_literal) {
-    // Normalize the properties of object to avoid n^2 behavior
-    // when extending the object multiple properties. Indicate the number of
-    // properties to be added.
+  bool should_normalize = should_transform || has_function_literal;
+  if (should_normalize) {
+    // TODO(verwaest): We might not want to ever normalize here.
     JSObject::NormalizeProperties(
         boilerplate, KEEP_INOBJECT_PROPERTIES, length / 2);
   }
+  Object::ValueType value_type = should_normalize
+      ? Object::FORCE_TAGGED : Object::OPTIMAL_REPRESENTATION;
 
   // TODO(verwaest): Support tracking representations in the boilerplate.
   for (int index = 0; index < length; index +=2) {
     Handle<Object> key(constant_properties->get(index+0), isolate);
     Handle<Object> value(constant_properties->get(index+1), isolate);
     if (value->IsFixedArray()) {
       // The value contains the constant_properties of a
       // simple object or array literal.
       Handle<FixedArray> array = Handle<FixedArray>::cast(value);
       ASSIGN_RETURN_ON_EXCEPTION(
           isolate, value,
           CreateLiteralBoilerplate(isolate, literals, array),
           Object);
     }
     MaybeHandle<Object> maybe_result;
     uint32_t element_index = 0;
     StoreMode mode = value->IsJSObject() ? FORCE_FIELD : ALLOW_AS_CONSTANT;
     if (key->IsInternalizedString()) {
       if (Handle<String>::cast(key)->AsArrayIndex(&element_index)) {
         // Array index as string (uint32).
         maybe_result = JSObject::SetOwnElement(
             boilerplate, element_index, value, SLOPPY);
       } else {
         Handle<String> name(String::cast(*key));
         ASSERT(!name->AsArrayIndex(&element_index));
         maybe_result = JSObject::SetOwnPropertyIgnoreAttributes(
             boilerplate, name, value, NONE,
-            Object::OPTIMAL_REPRESENTATION, mode);
+            value_type, mode);
       }
     } else if (key->ToArrayIndex(&element_index)) {
       // Array index (uint32).
       maybe_result = JSObject::SetOwnElement(
           boilerplate, element_index, value, SLOPPY);
     } else {
       // Non-uint32 number.
       ASSERT(key->IsNumber());
       double num = key->Number();
       char arr[100];
       Vector<char> buffer(arr, ARRAY_SIZE(arr));
       const char* str = DoubleToCString(num, buffer);
       Handle<String> name = isolate->factory()->NewStringFromAsciiChecked(str);
       maybe_result = JSObject::SetOwnPropertyIgnoreAttributes(
           boilerplate, name, value, NONE,
-          Object::OPTIMAL_REPRESENTATION, mode);
+          value_type, mode);
     }
     // If setting the property on the boilerplate throws an
     // exception, the exception is converted to an empty handle in
     // the handle based operations.  In that case, we need to
     // convert back to an exception.
     RETURN_ON_EXCEPTION(isolate, maybe_result, Object);
   }
 
   // Transform to fast properties if necessary. For object literals with
   // containing function literals we defer this operation until after all
@@ skipping 14893 matching lines @@
   }
   return NULL;
 }
 
 
 const Runtime::Function* Runtime::FunctionForId(Runtime::FunctionId id) {
   return &(kIntrinsicFunctions[static_cast<int>(id)]);
 }
 
 } }  // namespace v8::internal