Preallocate space in descriptor arrays.

src/bootstrapper.cc

 // Copyright 2012 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 366 matching lines @@
     function->shared()->set_instance_class_name(*symbol);
   }
   function->shared()->set_native(true);
   return function;
 }
 
 
 void Genesis::SetFunctionInstanceDescriptor(
     Handle<Map> map, PrototypePropertyMode prototypeMode) {
   int size = (prototypeMode == DONT_ADD_PROTOTYPE) ? 4 : 5;
-  Handle<DescriptorArray> descriptors(factory()->NewDescriptorArray(size));
+  Handle<DescriptorArray> descriptors(factory()->NewDescriptorArray(0, size));
   DescriptorArray::WhitenessWitness witness(*descriptors);
 
   Handle<Foreign> length(factory()->NewForeign(&Accessors::FunctionLength));
   Handle<Foreign> name(factory()->NewForeign(&Accessors::FunctionName));
   Handle<Foreign> args(factory()->NewForeign(&Accessors::FunctionArguments));
   Handle<Foreign> caller(factory()->NewForeign(&Accessors::FunctionCaller));
   Handle<Foreign> prototype;
   if (prototypeMode != DONT_ADD_PROTOTYPE) {
     prototype = factory()->NewForeign(&Accessors::FunctionPrototype);
   }
@@ skipping 120 matching lines @@
   empty_function_map->set_prototype(
       native_context()->object_function()->prototype());
   empty_function->set_map(*empty_function_map);
   return empty_function;
 }
 
 
 void Genesis::SetStrictFunctionInstanceDescriptor(
     Handle<Map> map, PrototypePropertyMode prototypeMode) {
   int size = (prototypeMode == DONT_ADD_PROTOTYPE) ? 4 : 5;
-  Handle<DescriptorArray> descriptors(factory()->NewDescriptorArray(size));
+  Handle<DescriptorArray> descriptors(factory()->NewDescriptorArray(0, size));
   DescriptorArray::WhitenessWitness witness(*descriptors);
 
   Handle<Foreign> length(factory()->NewForeign(&Accessors::FunctionLength));
   Handle<Foreign> name(factory()->NewForeign(&Accessors::FunctionName));
   Handle<AccessorPair> arguments(factory()->NewAccessorPair());
   Handle<AccessorPair> caller(factory()->NewAccessorPair());
   Handle<Foreign> prototype;
   if (prototypeMode != DONT_ADD_PROTOTYPE) {
     prototype = factory()->NewForeign(&Accessors::FunctionPrototype);
   }
@@ skipping 322 matching lines @@
                         Builtins::kArrayCode, true);
     array_function->shared()->set_construct_stub(
         isolate->builtins()->builtin(Builtins::kArrayConstructCode));
     array_function->shared()->DontAdaptArguments();
 
     // This seems a bit hackish, but we need to make sure Array.length
     // is 1.
     array_function->shared()->set_length(1);
 
     Handle<Map> initial_map(array_function->initial_map());
-    Handle<DescriptorArray> array_descriptors(factory->NewDescriptorArray(1));
+    Handle<DescriptorArray> array_descriptors(
+        factory->NewDescriptorArray(0, 1));
     DescriptorArray::WhitenessWitness witness(*array_descriptors);
 
     Handle<Foreign> array_length(factory->NewForeign(&Accessors::ArrayLength));
     PropertyAttributes attribs = static_cast<PropertyAttributes>(
         DONT_ENUM | DONT_DELETE);
     Map::SetDescriptors(initial_map, array_descriptors);
 
     {  // Add length.
       CallbacksDescriptor d(*factory->length_symbol(), *array_length, attribs);
       array_function->initial_map()->AppendDescriptor(&d, witness);
@@ skipping 26 matching lines @@
     Handle<JSFunction> string_fun =
         InstallFunction(global, "String", JS_VALUE_TYPE, JSValue::kSize,
                         isolate->initial_object_prototype(),
                         Builtins::kIllegal, true);
     string_fun->shared()->set_construct_stub(
         isolate->builtins()->builtin(Builtins::kStringConstructCode));
     native_context()->set_string_function(*string_fun);
 
     Handle<Map> string_map =
         Handle<Map>(native_context()->string_function()->initial_map());
-    Handle<DescriptorArray> string_descriptors(factory->NewDescriptorArray(1));
+    Handle<DescriptorArray> string_descriptors(
+        factory->NewDescriptorArray(0, 1));
     DescriptorArray::WhitenessWitness witness(*string_descriptors);
 
     Handle<Foreign> string_length(
         factory->NewForeign(&Accessors::StringLength));
     PropertyAttributes attribs = static_cast<PropertyAttributes>(
         DONT_ENUM | DONT_DELETE | READ_ONLY);
     Map::SetDescriptors(string_map, string_descriptors);
 
     {  // Add length.
       CallbacksDescriptor d(*factory->length_symbol(), *string_length, attribs);
@@ skipping 20 matching lines @@
                         Builtins::kIllegal, true);
     native_context()->set_regexp_function(*regexp_fun);
 
     ASSERT(regexp_fun->has_initial_map());
     Handle<Map> initial_map(regexp_fun->initial_map());
 
     ASSERT_EQ(0, initial_map->inobject_properties());
 
     PropertyAttributes final =
         static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY);
-    Handle<DescriptorArray> descriptors = factory->NewDescriptorArray(5);
+    Handle<DescriptorArray> descriptors = factory->NewDescriptorArray(0, 5);
     DescriptorArray::WhitenessWitness witness(*descriptors);
     Map::SetDescriptors(initial_map, descriptors);
 
     {
       // ECMA-262, section 15.10.7.1.
       FieldDescriptor field(heap->source_symbol(),
                             JSRegExp::kSourceFieldIndex,
                             final);
       initial_map->AppendDescriptor(&field, witness);
     }
@@ skipping 163 matching lines @@
     // Install the ThrowTypeError functions.
     callee->set_getter(*throw_function);
     callee->set_setter(*throw_function);
     caller->set_getter(*throw_function);
     caller->set_setter(*throw_function);
 
     // Create the map. Allocate one in-object field for length.
     Handle<Map> map = factory->NewMap(JS_OBJECT_TYPE,
                                       Heap::kArgumentsObjectSizeStrict);
     // Create the descriptor array for the arguments object.
-    Handle<DescriptorArray> descriptors = factory->NewDescriptorArray(3);
+    Handle<DescriptorArray> descriptors = factory->NewDescriptorArray(0, 3);
     DescriptorArray::WhitenessWitness witness(*descriptors);
     Map::SetDescriptors(map, descriptors);
 
     {  // length
       FieldDescriptor d(*factory->length_symbol(), 0, DONT_ENUM);
       map->AppendDescriptor(&d, witness);
     }
     {  // callee
       CallbacksDescriptor d(*factory->callee_symbol(),
                             *callee,
@@ skipping 326 matching lines @@
                         isolate()->initial_object_prototype(),
                         Builtins::kIllegal, false);
     Handle<JSObject> prototype =
         factory()->NewJSObject(isolate()->object_function(), TENURED);
     SetPrototype(script_fun, prototype);
     native_context()->set_script_function(*script_fun);
 
     Handle<Map> script_map = Handle<Map>(script_fun->initial_map());
 
     Handle<DescriptorArray> script_descriptors(
-        factory()->NewDescriptorArray(13));
+        factory()->NewDescriptorArray(0, 13));
     DescriptorArray::WhitenessWitness witness(*script_descriptors);
 
     Handle<Foreign> script_source(
         factory()->NewForeign(&Accessors::ScriptSource));
     Handle<Foreign> script_name(factory()->NewForeign(&Accessors::ScriptName));
     Handle<String> id_symbol(factory()->LookupAsciiSymbol("id"));
     Handle<Foreign> script_id(factory()->NewForeign(&Accessors::ScriptId));
     Handle<String> line_offset_symbol(
         factory()->LookupAsciiSymbol("line_offset"));
     Handle<Foreign> script_line_offset(
@@ skipping 157 matching lines @@
     // through a common bottleneck that would make the SMI_ONLY -> FAST_ELEMENT
     // transition easy to trap. Moreover, they rarely are smi-only.
     MaybeObject* maybe_map = array_function->initial_map()->Copy();
     Map* new_map;
     if (!maybe_map->To(&new_map)) return false;
     new_map->set_elements_kind(FAST_HOLEY_ELEMENTS);
     array_function->set_initial_map(new_map);
 
     // Make "length" magic on instances.
     Handle<Map> initial_map(array_function->initial_map());
-    Handle<DescriptorArray> array_descriptors(factory()->NewDescriptorArray(1));
+    Handle<DescriptorArray> array_descriptors(
+        factory()->NewDescriptorArray(0, 1));
     DescriptorArray::WhitenessWitness witness(*array_descriptors);
 
     Handle<Foreign> array_length(factory()->NewForeign(
         &Accessors::ArrayLength));
     PropertyAttributes attribs = static_cast<PropertyAttributes>(
         DONT_ENUM | DONT_DELETE);
     Map::SetDescriptors(initial_map, array_descriptors);
 
     {  // Add length.
       CallbacksDescriptor d(
@@ skipping 79 matching lines @@
     Handle<Map> initial_map =
         factory()->NewMap(JS_ARRAY_TYPE, JSRegExpResult::kSize);
     initial_map->set_constructor(*array_constructor);
 
     // Set prototype on map.
     initial_map->set_non_instance_prototype(false);
     initial_map->set_prototype(*array_prototype);
 
     // Update map with length accessor from Array and add "index" and "input".
     Handle<DescriptorArray> reresult_descriptors =
-        factory()->NewDescriptorArray(3);
+        factory()->NewDescriptorArray(0, 3);
     DescriptorArray::WhitenessWitness witness(*reresult_descriptors);
     Map::SetDescriptors(initial_map, reresult_descriptors);
 
     {
       JSFunction* array_function = native_context()->array_function();
       Handle<DescriptorArray> array_descriptors(
           array_function->initial_map()->instance_descriptors());
       String* length = heap()->length_symbol();
       int old = array_descriptors->SearchWithCache(
           length, array_function->initial_map());
@@ skipping 617 matching lines @@
   return from + sizeof(NestingCounterType);
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   ASSERT(!IsActive());
 }
 
 } }  // namespace v8::internal