Optimizing nested, constant object literals (like JSON objects) by building o...

src/runtime.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 81 matching lines @@
 }
 
 
 static Object* Runtime_CloneObjectLiteralBoilerplate(Arguments args) {
   CONVERT_CHECKED(JSObject, boilerplate, args[0]);
   return Heap::CopyJSObject(boilerplate);
 }
 
 
 static Handle<Map> ComputeObjectLiteralMap(
-    Handle<Context> context,
-    Handle<FixedArray> constant_properties,
-    bool* is_result_from_cache) {
+      Handle<Context> context,
+      Handle<FixedArray> constant_properties,
+      bool* is_result_from_cache) {
   int number_of_properties = constant_properties->length() / 2;
   if (FLAG_canonicalize_object_literal_maps) {
     // First find prefix of consecutive symbol keys.
     int number_of_symbol_keys = 0;
     while ((number_of_symbol_keys < number_of_properties) &&
            (constant_properties->get(number_of_symbol_keys*2)->IsSymbol())) {
       number_of_symbol_keys++;
     }
     // Based on the number of prefix symbols key we decide whether
     // to use the map cache in the global context.
     const int kMaxKeys = 10;
     if ((number_of_symbol_keys == number_of_properties) &&
         (number_of_symbol_keys < kMaxKeys)) {
       // Create the fixed array with the key.
       Handle<FixedArray> keys = Factory::NewFixedArray(number_of_symbol_keys);
       for (int i = 0; i < number_of_symbol_keys; i++) {
         keys->set(i, constant_properties->get(i*2));
       }
       *is_result_from_cache = true;
       return Factory::ObjectLiteralMapFromCache(context, keys);
     }
   }
   *is_result_from_cache = false;
   return Factory::CopyMap(
       Handle<Map>(context->object_function()->initial_map()),
       number_of_properties);
 }
 
 
-static Object* Runtime_CreateObjectLiteralBoilerplate(Arguments args) {
-  HandleScope scope;
-  ASSERT(args.length() == 3);
-  // Copy the arguments.
-  Handle<FixedArray> literals = args.at<FixedArray>(0);
-  int literals_index = Smi::cast(args[1])->value();
-  Handle<FixedArray> constant_properties = args.at<FixedArray>(2);
-
+static Handle<Object> CreateObjectLiteralBoilerplate(
+      Handle<FixedArray> literals,
+      Handle<FixedArray> constant_properties) {
   // Get the global context from the literals array.  This is the
   // context in which the function was created and we use the object
   // function from this context to create the object literal.  We do
   // not use the object function from the current global context
   // because this might be the object function from another context
   // which we should not have access to.
   Handle<Context> context =
       Handle<Context>(JSFunction::GlobalContextFromLiterals(*literals));
 
   bool is_result_from_cache;
   Handle<Map> map = ComputeObjectLiteralMap(context,
                                             constant_properties,
                                             &is_result_from_cache);
 
   Handle<JSObject> boilerplate = Factory::NewJSObjectFromMap(map);
   {  // Add the constant properties to the boilerplate.
     int length = constant_properties->length();
     OptimizedObjectForAddingMultipleProperties opt(boilerplate,
                                                    !is_result_from_cache);
     for (int index = 0; index < length; index +=2) {
       Handle<Object> key(constant_properties->get(index+0));
       Handle<Object> value(constant_properties->get(index+1));
+      if (value->IsFixedArray()) {
+        // The value contains the constant_properties of a
+        // simple object literal.
+        Handle<FixedArray> array = Handle<FixedArray>::cast(value);
+        value = CreateObjectLiteralBoilerplate(literals, array);
+      }
       Handle<Object> result;
       uint32_t element_index = 0;
       if (key->IsSymbol()) {
         // If key is a symbol it is not an array element.
         Handle<String> name(String::cast(*key));
         ASSERT(!name->AsArrayIndex(&element_index));
         result = SetProperty(boilerplate, name, value, NONE);
       } else if (Array::IndexFromObject(*key, &element_index)) {
         // Array index (uint32).
         result = SetElement(boilerplate, element_index, value);
       } 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 = Factory::NewStringFromAscii(CStrVector(str));
         result = SetProperty(boilerplate, name, value, NONE);
       }
       // 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.
-      if (result.is_null()) return Failure::Exception();
+      if (result.is_null()) return result;
     }
   }
 
-  // Update the functions literal and return the boilerplate.
-  literals->set(literals_index, *boilerplate);
-
-  return *boilerplate;
+  return boilerplate;
 }
 
 
+static Object* Runtime_CreateObjectLiteralBoilerplate(Arguments args) {
+  HandleScope scope;
+  ASSERT(args.length() == 3);
+  // Copy the arguments.
+  Handle<FixedArray> literals = args.at<FixedArray>(0);
+  int literals_index = Smi::cast(args[1])->value();
+  Handle<FixedArray> constant_properties = args.at<FixedArray>(2);
+
+  Handle<Object> result =
+    CreateObjectLiteralBoilerplate(literals, constant_properties);
+
+  if (result.is_null()) return Failure::Exception();
+
+  // Update the functions literal and return the boilerplate.
+  literals->set(literals_index, *result);;
+
+  return *result;
+}
+
+
 static Object* Runtime_CreateArrayLiteral(Arguments args) {
   // Takes a FixedArray of elements containing the literal elements of
   // the array literal and produces JSArray with those elements.
   // Additionally takes the literals array of the surrounding function
   // which contains the context from which to get the Array function
   // to use for creating the array literal.
   ASSERT(args.length() == 2);
   CONVERT_CHECKED(FixedArray, elements, args[0]);
   CONVERT_CHECKED(FixedArray, literals, args[1]);
   JSFunction* constructor =
@@ skipping 5909 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage();
   }
 }
 
 
 } }  // namespace v8::internal