Get rid of ConvertFieldToDescriptor and simplify related code.

src/objects.cc

 // Copyright 2013 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 1898 matching lines @@
     }
   }
   return true;
 }
 
 
 MaybeObject* JSObject::AddFastProperty(Name* name,
                                        Object* value,
                                        PropertyAttributes attributes,
                                        StoreFromKeyed store_mode,
-                                       ValueType value_type) {
+                                       ValueType value_type,
+                                       TransitionFlag flag) {
   ASSERT(!IsJSGlobalProxy());
   ASSERT(DescriptorArray::kNotFound ==
          map()->instance_descriptors()->Search(
              name, map()->NumberOfOwnDescriptors()));
 
   // Normalize the object if the name is an actual name (not the
   // hidden strings) and is not a real identifier.
   // Normalize the object if it will have too many fast properties.
   Isolate* isolate = GetHeap()->isolate();
-  if ((!name->IsSymbol() && !IsIdentifier(isolate->unicode_cache(), name)
-       && name != isolate->heap()->hidden_string()) ||
-      (map()->unused_property_fields() == 0 &&
-       TooManyFastProperties(properties()->length(), store_mode))) {
-    Object* obj;
-    MaybeObject* maybe_obj =
+  if ((!name->IsSymbol() &&
+       !IsIdentifier(isolate->unicode_cache(), name) &&
+       name != isolate->heap()->hidden_string()) ||
+      TooManyFastProperties(store_mode)) {
+    MaybeObject* maybe_failure =
         NormalizeProperties(CLEAR_INOBJECT_PROPERTIES, 0);
-    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
-
+    if (maybe_failure->IsFailure()) return maybe_failure;
     return AddSlowProperty(name, value, attributes);
   }
 
   // Compute the new index for new field.
   int index = map()->NextFreePropertyIndex();
 
   // Allocate new instance descriptors with (name, index) added
   if (IsJSContextExtensionObject()) value_type = FORCE_TAGGED;
   Representation representation = value->OptimalRepresentation(value_type);
 
   FieldDescriptor new_field(name, index, attributes, representation);
 
   ASSERT(index < map()->inobject_properties() ||
          (index - map()->inobject_properties()) < properties()->length() ||
          map()->unused_property_fields() == 0);
 
   FixedArray* values = NULL;
 
   // TODO(verwaest): Merge with AddFastPropertyUsingMap.
   if (map()->unused_property_fields() == 0) {
     // Make room for the new value
     MaybeObject* maybe_values =
         properties()->CopySize(properties()->length() + kFieldsAdded);
     if (!maybe_values->To(&values)) return maybe_values;
   }
 
-  TransitionFlag flag = INSERT_TRANSITION;
-
   Heap* heap = isolate->heap();
 
   Object* storage;
   MaybeObject* maybe_storage =
       value->AllocateNewStorageFor(heap, representation);
   if (!maybe_storage->To(&storage)) return maybe_storage;
 
   // Note that Map::CopyAddDescriptor has side-effects, the new map is already
   // inserted in the transition tree. No more allocations that might fail are
   // allowed after this point.
@@ skipping 12 matching lines @@
   set_map(new_map);
 
   FastPropertyAtPut(index, storage);
   return value;
 }
 
 
 MaybeObject* JSObject::AddConstantProperty(
     Name* name,
     Object* constant,
-    PropertyAttributes attributes) {
+    PropertyAttributes attributes,
+    TransitionFlag initial_flag) {
   // Allocate new instance descriptors with (name, constant) added
   ConstantDescriptor d(name, constant, attributes);
 
   TransitionFlag flag =
       // Do not add transitions to global objects.
       (IsGlobalObject() ||
       // Don't add transitions to special properties with non-trivial
       // attributes.
        attributes != NONE)
       ? OMIT_TRANSITION
-      : INSERT_TRANSITION;
+      : initial_flag;
 
   Map* new_map;
   MaybeObject* maybe_new_map = map()->CopyAddDescriptor(&d, flag);
   if (!maybe_new_map->To(&new_map)) return maybe_new_map;
 
   set_map(new_map);
   return constant;
 }
 
 
@@ skipping 39 matching lines @@
 }
 
 
 MaybeObject* JSObject::AddProperty(Name* name,
                                    Object* value,
                                    PropertyAttributes attributes,
                                    StrictModeFlag strict_mode,
                                    JSReceiver::StoreFromKeyed store_mode,
                                    ExtensibilityCheck extensibility_check,
                                    ValueType value_type,
-                                   StoreMode mode) {
+                                   StoreMode mode,
+                                   TransitionFlag transition_flag) {
   ASSERT(!IsJSGlobalProxy());
   Map* map_of_this = map();
   Heap* heap = GetHeap();
   Isolate* isolate = heap->isolate();
   MaybeObject* result;
   if (extensibility_check == PERFORM_EXTENSIBILITY_CHECK &&
       !map_of_this->is_extensible()) {
     if (strict_mode == kNonStrictMode) {
       return value;
     } else {
       Handle<Object> args[1] = {Handle<Name>(name)};
       return isolate->Throw(
           *isolate->factory()->NewTypeError("object_not_extensible",
                                             HandleVector(args, 1)));
     }
   }
 
   if (HasFastProperties()) {
     // Ensure the descriptor array does not get too big.
     if (map_of_this->NumberOfOwnDescriptors() <
         DescriptorArray::kMaxNumberOfDescriptors) {
       // TODO(verwaest): Support other constants.
       // if (mode == ALLOW_AS_CONSTANT &&
       //     !value->IsTheHole() &&
       //     !value->IsConsString()) {
       if (value->IsJSFunction()) {
-        result = AddConstantProperty(name, value, attributes);
+        result = AddConstantProperty(name, value, attributes, transition_flag);
       } else {
         result = AddFastProperty(
-            name, value, attributes, store_mode, value_type);
+            name, value, attributes, store_mode, value_type, transition_flag);
       }
     } else {
       // Normalize the object to prevent very large instance descriptors.
       // This eliminates unwanted N^2 allocation and lookup behavior.
       Object* obj;
       MaybeObject* maybe = NormalizeProperties(CLEAR_INOBJECT_PROPERTIES, 0);
       if (!maybe->To(&obj)) return maybe;
       result = AddSlowProperty(name, value, attributes);
     }
   } else {
@@ skipping 83 matching lines @@
   if (old_index != -1) {
     // All calls to ReplaceSlowProperty have had all transitions removed.
     new_enumeration_index = dictionary->DetailsAt(old_index).dictionary_index();
   }
 
   PropertyDetails new_details(attributes, NORMAL, new_enumeration_index);
   return SetNormalizedProperty(name, value, new_details);
 }
 
 
-MaybeObject* JSObject::ConvertDescriptorToField(Name* name,
-                                                Object* new_value,
-                                                PropertyAttributes attributes,
-                                                TransitionFlag flag) {
-  if (map()->unused_property_fields() == 0 &&
-      TooManyFastProperties(properties()->length(), MAY_BE_STORE_FROM_KEYED)) {
-    Object* obj;
-    MaybeObject* maybe_obj = NormalizeProperties(CLEAR_INOBJECT_PROPERTIES, 0);
-    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
-    return ReplaceSlowProperty(name, new_value, attributes);
-  }
-
-  Representation representation = IsJSContextExtensionObject()
-      ? Representation::Tagged() : new_value->OptimalRepresentation();
-  int index = map()->NextFreePropertyIndex();
-  FieldDescriptor new_field(name, index, attributes, representation);
-
-  // Make a new map for the object.
-  Map* new_map;
-  MaybeObject* maybe_new_map = map()->CopyInsertDescriptor(&new_field, flag);
-  if (!maybe_new_map->To(&new_map)) return maybe_new_map;
-
-  // Make new properties array if necessary.
-  FixedArray* new_properties = NULL;
-  int new_unused_property_fields = map()->unused_property_fields() - 1;
-  if (map()->unused_property_fields() == 0) {
-    new_unused_property_fields = kFieldsAdded - 1;
-    MaybeObject* maybe_new_properties =
-        properties()->CopySize(properties()->length() + kFieldsAdded);
-    if (!maybe_new_properties->To(&new_properties)) return maybe_new_properties;
-  }
-
-  Heap* heap = GetHeap();
-  Object* storage;
-  MaybeObject* maybe_storage =
-      new_value->AllocateNewStorageFor(heap, representation);
-  if (!maybe_storage->To(&storage)) return maybe_storage;
-
-  // Update pointers to commit changes.
-  // Object points to the new map.
-  new_map->set_unused_property_fields(new_unused_property_fields);
-  set_map(new_map);
-  if (new_properties != NULL) {
-    set_properties(new_properties);
-  }
-  FastPropertyAtPut(index, storage);
-  return new_value;
-}
-
-
 const char* Representation::Mnemonic() const {
   switch (kind_) {
     case kNone: return "v";
     case kTagged: return "t";
     case kSmi: return "s";
     case kDouble: return "d";
     case kInteger32: return "i";
     case kHeapObject: return "h";
     case kExternal: return "x";
     default:
@@ skipping 126 matching lines @@
   if (!maybe_array->To(&array)) return maybe_array;
 
   DescriptorArray* old_descriptors = old_map->instance_descriptors();
   DescriptorArray* new_descriptors = new_map->instance_descriptors();
   int descriptors = new_map->NumberOfOwnDescriptors();
 
   for (int i = 0; i < descriptors; i++) {
     PropertyDetails details = new_descriptors->GetDetails(i);
     if (details.type() != FIELD) continue;
     PropertyDetails old_details = old_descriptors->GetDetails(i);
+    if (old_details.type() == CALLBACKS) continue;
     ASSERT(old_details.type() == CONSTANT ||
            old_details.type() == FIELD);
     Object* value = old_details.type() == CONSTANT
         ? old_descriptors->GetValue(i)
         : RawFastPropertyAt(old_descriptors->GetFieldIndex(i));
     if (FLAG_track_double_fields &&
         !old_details.representation().IsDouble() &&
         details.representation().IsDouble()) {
       if (old_details.representation().IsNone()) value = Smi::FromInt(0);
       // Objects must be allocated in the old object space, since the
@@ skipping 1380 matching lines @@
                                                Handle<Name> name,
                                                Handle<Object> value,
                                                PropertyAttributes attributes) {
   Map* transition_map = lookup->GetTransitionTarget();
   int descriptor = transition_map->LastAdded();
 
   DescriptorArray* descriptors = transition_map->instance_descriptors();
   PropertyDetails details = descriptors->GetDetails(descriptor);
 
   if (details.type() == CALLBACKS || attributes != details.attributes()) {
-    return lookup->holder()->ConvertDescriptorToField(
-        *name, *value, attributes);
+    // AddProperty will either normalize the object, or create a new fast copy
+    // of the map. If we get a fast copy of the map, all field representations
+    // will be tagged since the transition is omitted.
+    return lookup->holder()->AddProperty(
+        *name, *value, attributes, kNonStrictMode,
+        JSReceiver::CERTAINLY_NOT_STORE_FROM_KEYED,
+        JSReceiver::OMIT_EXTENSIBILITY_CHECK,
+        JSObject::FORCE_TAGGED, FORCE_FIELD, OMIT_TRANSITION);
   }
 
   // Keep the target CONSTANT if the same value is stored.
   // TODO(verwaest): Also support keeping the placeholder
   // (value->IsUninitialized) as constant.
   if (details.type() == CONSTANT &&
       descriptors->GetValue(descriptor) == *value) {
     lookup->holder()->set_map(transition_map);
     return *value;
   }
@@ skipping 282 matching lines @@
     case FIELD:
       if (value->IsUninitialized()) break;
       result = SetPropertyToField(&lookup, name, value);
       break;
     case CONSTANT:
       // Only replace the constant if necessary.
       if (*value == lookup.GetConstant()) return *value;
       if (value->IsUninitialized()) break;
       result = SetPropertyToField(&lookup, name, value);
       break;
-    case CALLBACKS:
     case INTERCEPTOR:
-      // Override callback in clone
-      result = self->ConvertDescriptorToField(*name, *value, attributes);
+      result = self->AddProperty(
+          *name, *value, attributes, kNonStrictMode,
+          MAY_BE_STORE_FROM_KEYED, extensibility_check, value_type, mode);
       break;
+    case CALLBACKS: {
+      if (TooManyFastProperties()) {
+        MaybeObject* maybe_failure =
+            NormalizeProperties(CLEAR_INOBJECT_PROPERTIES, 0);
+        if (maybe_failure->IsFailure()) return maybe_failure;
+      }
+
+      if (!self->HasFastProperties()) {
+        result = ReplaceSlowProperty(*name, *value, attributes);
+        break;

[rossberg, 2013/08/23 09:24:14]

Nit: I'd prefer an if-else instead of a goto.

+      }
+
+      int descriptor_index = lookup.GetDescriptorIndex();
+      MaybeObject* maybe_failure = self->GeneralizeFieldRepresentation(
+          descriptor_index, Representation::Tagged(), FORCE_FIELD);
+      if (maybe_failure->IsFailure()) return maybe_failure;
+      DescriptorArray* descriptors = self->map()->instance_descriptors();
+      int index = descriptors->GetDetails(descriptor_index).field_index();
+      self->FastPropertyAtPut(index, *value);
+      result = *value;
+      break;
+    }
     case TRANSITION:
       result = SetPropertyUsingTransition(&lookup, name, value, attributes);
       break;
     case HANDLER:
     case NONEXISTENT:
       UNREACHABLE();
   }
 
   Handle<Object> hresult;
   if (!result->ToHandle(&hresult, isolate)) return result;
@@ skipping 11834 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal