Increment descriptor array slack for prototypes by a constant rather than 50%

src/api-natives.cc

 // Copyright 2015 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/api-natives.h"
 
 #include "src/api.h"
 #include "src/isolate.h"
 #include "src/lookup.h"
 #include "src/messages.h"
@@ skipping 19 matching lines @@
     return InstantiateFunction(isolate,
                                Handle<FunctionTemplateInfo>::cast(data), name);
   } else if (data->IsObjectTemplateInfo()) {
     return InstantiateObject(isolate, Handle<ObjectTemplateInfo>::cast(data));
   } else {
     return data;
   }
 }
 
 
-MaybeHandle<Object> DefineAccessorProperty(
-    Isolate* isolate, Handle<JSObject> object, Handle<Name> name,
-    Handle<Object> getter, Handle<Object> setter, Smi* attributes) {
-  DCHECK(PropertyDetails::AttributesField::is_valid(
-      static_cast<PropertyAttributes>(attributes->value())));
+MaybeHandle<Object> DefineAccessorProperty(Isolate* isolate,
+                                           Handle<JSObject> object,
+                                           Handle<Name> name,
+                                           Handle<Object> getter,
+                                           Handle<Object> setter,
+                                           PropertyAttributes attributes) {
   if (!getter->IsUndefined()) {
     ASSIGN_RETURN_ON_EXCEPTION(
         isolate, getter,
         InstantiateFunction(isolate,
                             Handle<FunctionTemplateInfo>::cast(getter)),
         Object);
   }
   if (!setter->IsUndefined()) {
     ASSIGN_RETURN_ON_EXCEPTION(
         isolate, setter,
         InstantiateFunction(isolate,
                             Handle<FunctionTemplateInfo>::cast(setter)),
         Object);
   }
-  RETURN_ON_EXCEPTION(isolate,
-                      JSObject::DefineAccessor(
-                          object, name, getter, setter,
-                          static_cast<PropertyAttributes>(attributes->value())),
+  RETURN_ON_EXCEPTION(isolate, JSObject::DefineAccessor(object, name, getter,
+                                                        setter, attributes),
                       Object);
   return object;
 }
 
 
 MaybeHandle<Object> DefineDataProperty(Isolate* isolate,
                                        Handle<JSObject> object,
                                        Handle<Name> name,
                                        Handle<Object> prop_data,
-                                       Smi* unchecked_attributes) {
-  DCHECK((unchecked_attributes->value() &
-          ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
-  // Compute attributes.
-  PropertyAttributes attributes =
-      static_cast<PropertyAttributes>(unchecked_attributes->value());
-
+                                       PropertyAttributes attributes) {
   Handle<Object> value;
   ASSIGN_RETURN_ON_EXCEPTION(isolate, value,
                              Instantiate(isolate, prop_data, name), Object);
 
   LookupIterator it = LookupIterator::PropertyOrElement(
       isolate, object, name, LookupIterator::OWN_SKIP_INTERCEPTOR);
 
 #ifdef DEBUG
   Maybe<PropertyAttributes> maybe = JSReceiver::GetPropertyAttributes(&it);
   DCHECK(maybe.IsJust());
@@ skipping 54 matching lines @@
 MaybeHandle<JSObject> ConfigureInstance(Isolate* isolate, Handle<JSObject> obj,
                                         Handle<TemplateInfo> data) {
   auto property_list = handle(data->property_list(), isolate);
   if (property_list->IsUndefined()) return obj;
   // TODO(dcarney): just use a FixedArray here.
   NeanderArray properties(property_list);
   if (properties.length() == 0) return obj;
   HandleScope scope(isolate);
   // Disable access checks while instantiating the object.
   AccessCheckDisableScope access_check_scope(isolate, obj);
-  for (int i = 0; i < properties.length();) {
+
+  int i = 0;
+  for (int c = 0; c < data->number_of_properties(); c++) {
     int length = Smi::cast(properties.get(i))->value();
-    if (length == 3) {
-      auto name = handle(Name::cast(properties.get(i + 1)), isolate);
-      auto prop_data = handle(properties.get(i + 2), isolate);
-      auto attributes = Smi::cast(properties.get(i + 3));
+    PropertyKind kind = length == 3 ? kData : kAccessor;

[Igor Sheludko, 2015/07/03 13:56:40]

Instead of writing a length we could pack kind and attributes into
PropertyDetails to save one word per property.

+    auto name = handle(Name::cast(properties.get(i + 1)), isolate);
+    auto unchecked_attributes = Smi::cast(properties.get(i + 2));
+    PropertyAttributes attributes =
+        static_cast<PropertyAttributes>(unchecked_attributes->value());
+    DCHECK(PropertyDetails::AttributesField::is_valid(attributes));
+
+    if (TransitionArray::SearchTransition(obj->map(), kind, *name,

[Igor Sheludko, 2015/07/03 13:56:40]

Put this call after all the simple checks.

+                                          attributes) == NULL &&
+        obj->map()->owns_descriptors() &&
+        obj->map()->instance_descriptors()->length() != 0 &&
+        obj->map()->instance_descriptors()->NumberOfSlackDescriptors() == 0) {
+      Map::EnsureDescriptorSlack(handle(obj->map()),
+                                 data->number_of_properties() - c);
+    }
+
+    if (kind == kData) {
+      auto prop_data = handle(properties.get(i + 3), isolate);
+
       RETURN_ON_EXCEPTION(isolate, DefineDataProperty(isolate, obj, name,
                                                       prop_data, attributes),
                           JSObject);
     } else {
-      DCHECK(length == 4);
-      auto name = handle(Name::cast(properties.get(i + 1)), isolate);
-      auto getter = handle(properties.get(i + 2), isolate);
-      auto setter = handle(properties.get(i + 3), isolate);
-      auto attributes = Smi::cast(properties.get(i + 4));
+      DCHECK_EQ(4, length);
+      auto getter = handle(properties.get(i + 3), isolate);
+      auto setter = handle(properties.get(i + 4), isolate);
       RETURN_ON_EXCEPTION(isolate,
                           DefineAccessorProperty(isolate, obj, name, getter,
                                                  setter, attributes),
                           JSObject);
     }
     i += length + 1;
   }
   return obj;
 }
 
@@ skipping 126 matching lines @@
 };
 
 
 void AddPropertyToPropertyList(Isolate* isolate, Handle<TemplateInfo> templ,
                                int length, Handle<Object>* data) {
   auto list = handle(templ->property_list(), isolate);
   if (list->IsUndefined()) {
     list = NeanderArray(isolate).value();
     templ->set_property_list(*list);
   }
+  templ->set_number_of_properties(templ->number_of_properties() + 1);
   NeanderArray array(list);
   array.add(isolate, isolate->factory()->NewNumberFromInt(length));
   for (int i = 0; i < length; i++) {
     Handle<Object> value =
         data[i].is_null()
             ? Handle<Object>::cast(isolate->factory()->undefined_value())
             : data[i];
     array.add(isolate, value);
   }
 }
@@ skipping 33 matching lines @@
 }
 
 
 void ApiNatives::AddDataProperty(Isolate* isolate, Handle<TemplateInfo> info,
                                  Handle<Name> name, Handle<Object> value,
                                  PropertyAttributes attributes) {
   const int kSize = 3;
   DCHECK(Smi::IsValid(static_cast<int>(attributes)));
   auto attribute_handle =
       handle(Smi::FromInt(static_cast<int>(attributes)), isolate);
-  Handle<Object> data[kSize] = {name, value, attribute_handle};
+  Handle<Object> data[kSize] = {name, attribute_handle, value};
   AddPropertyToPropertyList(isolate, info, kSize, data);
 }
 
 
 void ApiNatives::AddAccessorProperty(Isolate* isolate,
                                      Handle<TemplateInfo> info,
                                      Handle<Name> name,
                                      Handle<FunctionTemplateInfo> getter,
                                      Handle<FunctionTemplateInfo> setter,
                                      PropertyAttributes attributes) {
   const int kSize = 4;
   DCHECK(Smi::IsValid(static_cast<int>(attributes)));
   auto attribute_handle =
       handle(Smi::FromInt(static_cast<int>(attributes)), isolate);
-  Handle<Object> data[kSize] = {name, getter, setter, attribute_handle};
+  Handle<Object> data[kSize] = {name, attribute_handle, getter, setter};
   AddPropertyToPropertyList(isolate, info, kSize, data);
 }
 
 
 void ApiNatives::AddNativeDataProperty(Isolate* isolate,
                                        Handle<TemplateInfo> info,
                                        Handle<AccessorInfo> property) {
   auto list = handle(info->property_accessors(), isolate);
   if (list->IsUndefined()) {
     list = NeanderArray(isolate).value();
@@ skipping 176 matching lines @@
     Handle<AccessorInfo> accessor(AccessorInfo::cast(array->get(i)));
     JSObject::SetAccessor(result, accessor).Assert();
   }
 
   DCHECK(result->shared()->IsApiFunction());
   return result;
 }
 
 }  // namespace internal
 }  // namespace v8