| // Copyright 2017 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/objects/literal-objects.h" |
| |
| #include "src/accessors.h" |
| #include "src/ast/ast.h" |
| #include "src/factory.h" |
| #include "src/isolate.h" |
| #include "src/objects-inl.h" |
| #include "src/objects/literal-objects-inl.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| Object* BoilerplateDescription::name(int index) const { |
| // get() already checks for out of bounds access, but we do not want to allow |
| // access to the last element, if it is the number of properties. |
| DCHECK_NE(size(), index); |
| return get(2 * index); |
| } |
| |
| Object* BoilerplateDescription::value(int index) const { |
| return get(2 * index + 1); |
| } |
| |
| int BoilerplateDescription::size() const { |
| DCHECK_EQ(0, (length() - (this->has_number_of_properties() ? 1 : 0)) % 2); |
| // Rounding is intended. |
| return length() / 2; |
| } |
| |
| int BoilerplateDescription::backing_store_size() const { |
| if (has_number_of_properties()) { |
| // If present, the last entry contains the number of properties. |
| return Smi::ToInt(this->get(length() - 1)); |
| } |
| // If the number is not given explicitly, we assume there are no |
| // properties with computed names. |
| return size(); |
| } |
| |
| void BoilerplateDescription::set_backing_store_size(Isolate* isolate, |
| int backing_store_size) { |
| DCHECK(has_number_of_properties()); |
| DCHECK_NE(size(), backing_store_size); |
| Handle<Object> backing_store_size_obj = |
| isolate->factory()->NewNumberFromInt(backing_store_size); |
| set(length() - 1, *backing_store_size_obj); |
| } |
| |
| bool BoilerplateDescription::has_number_of_properties() const { |
| return length() % 2 != 0; |
| } |
| |
| namespace { |
| |
| inline int EncodeComputedEntry(ClassBoilerplate::ValueKind value_kind, |
| unsigned key_index) { |
| typedef ClassBoilerplate::ComputedEntryFlags Flags; |
| int flags = Flags::ValueKindBits::encode(value_kind) | |
| Flags::KeyIndexBits::encode(key_index); |
| return flags; |
| } |
| |
| void AddToDescriptorArrayTemplate( |
| Isolate* isolate, Handle<DescriptorArray> descriptor_array_template, |
| Handle<Name> name, ClassBoilerplate::ValueKind value_kind, |
| Handle<Object> value) { |
| int entry = descriptor_array_template->Search( |
| *name, descriptor_array_template->number_of_descriptors()); |
| // TODO(ishell): deduplicate properties at AST level, this will allow us to |
| // avoid creation of closures that will be overwritten anyway. |
| if (entry == DescriptorArray::kNotFound) { |
| // Entry not found, add new one. |
| Descriptor d; |
| if (value_kind == ClassBoilerplate::kData) { |
| d = Descriptor::DataConstant(name, value, DONT_ENUM); |
| } else { |
| DCHECK(value_kind == ClassBoilerplate::kGetter || |
| value_kind == ClassBoilerplate::kSetter); |
| Handle<AccessorPair> pair = isolate->factory()->NewAccessorPair(); |
| pair->set(value_kind == ClassBoilerplate::kGetter ? ACCESSOR_GETTER |
| : ACCESSOR_SETTER, |
| *value); |
| d = Descriptor::AccessorConstant(name, pair, DONT_ENUM); |
| } |
| descriptor_array_template->Append(&d); |
| |
| } else { |
| // Entry found, update it. |
| int sorted_index = descriptor_array_template->GetDetails(entry).pointer(); |
| if (value_kind == ClassBoilerplate::kData) { |
| Descriptor d = Descriptor::DataConstant(name, value, DONT_ENUM); |
| d.SetSortedKeyIndex(sorted_index); |
| descriptor_array_template->Set(entry, &d); |
| } else { |
| DCHECK(value_kind == ClassBoilerplate::kGetter || |
| value_kind == ClassBoilerplate::kSetter); |
| Object* raw_accessor = descriptor_array_template->GetValue(entry); |
| AccessorPair* pair; |
| if (raw_accessor->IsAccessorPair()) { |
| pair = AccessorPair::cast(raw_accessor); |
| } else { |
| Handle<AccessorPair> new_pair = isolate->factory()->NewAccessorPair(); |
| Descriptor d = Descriptor::AccessorConstant(name, new_pair, DONT_ENUM); |
| d.SetSortedKeyIndex(sorted_index); |
| descriptor_array_template->Set(entry, &d); |
| pair = *new_pair; |
| } |
| pair->set(value_kind == ClassBoilerplate::kGetter ? ACCESSOR_GETTER |
| : ACCESSOR_SETTER, |
| *value); |
| } |
| } |
| } |
| |
| Handle<NameDictionary> DictionaryAddNoUpdateNextEnumerationIndex( |
| Handle<NameDictionary> dictionary, Handle<Name> name, Handle<Object> value, |
| PropertyDetails details, int* entry_out = nullptr) { |
| return NameDictionary::AddNoUpdateNextEnumerationIndex( |
| dictionary, name, value, details, entry_out); |
| } |
| |
| Handle<NumberDictionary> DictionaryAddNoUpdateNextEnumerationIndex( |
| Handle<NumberDictionary> dictionary, uint32_t element, Handle<Object> value, |
| PropertyDetails details, int* entry_out = nullptr) { |
| // NumberDictionary does not maintain the enumeration order, so it's |
| // a normal Add(). |
| return NumberDictionary::Add(dictionary, element, value, details, entry_out); |
| } |
| |
| void DictionaryUpdateMaxNumberKey(Handle<NameDictionary> dictionary, |
| Handle<Name> name) { |
| // No-op for name dictionaries. |
| } |
| |
| void DictionaryUpdateMaxNumberKey(Handle<NumberDictionary> dictionary, |
| uint32_t element) { |
| dictionary->UpdateMaxNumberKey(element, Handle<JSObject>()); |
| dictionary->set_requires_slow_elements(); |
| } |
| |
| constexpr int ComputeEnumerationIndex(int value_index) { |
| // We "shift" value indices to ensure that the enumeration index for the value |
| // will not overlap with minimum properties set for both class and prototype |
| // objects. |
| return value_index + Max(ClassBoilerplate::kMinimumClassPropertiesCount, |
| ClassBoilerplate::kMinimumPrototypePropertiesCount); |
| } |
| |
| inline int GetExistingValueIndex(Object* value) { |
| return value->IsSmi() ? Smi::ToInt(value) : -1; |
| } |
| |
| template <typename Dictionary, typename Key> |
| void AddToDictionaryTemplate(Isolate* isolate, Handle<Dictionary> dictionary, |
| Key key, int key_index, |
| ClassBoilerplate::ValueKind value_kind, |
| Object* value) { |
| int entry = dictionary->FindEntry(isolate, key); |
| |
| if (entry == kNotFound) { |
| // Entry not found, add new one. |
| const bool is_elements_dictionary = |
| std::is_same<Dictionary, NumberDictionary>::value; |
| STATIC_ASSERT(is_elements_dictionary != |
| (std::is_same<Dictionary, NameDictionary>::value)); |
| int enum_order = |
| is_elements_dictionary ? 0 : ComputeEnumerationIndex(key_index); |
| Handle<Object> value_handle; |
| PropertyDetails details( |
| value_kind != ClassBoilerplate::kData ? kAccessor : kData, DONT_ENUM, |
| PropertyCellType::kNoCell, enum_order); |
| |
| if (value_kind == ClassBoilerplate::kData) { |
| value_handle = handle(value, isolate); |
| } else { |
| AccessorComponent component = value_kind == ClassBoilerplate::kGetter |
| ? ACCESSOR_GETTER |
| : ACCESSOR_SETTER; |
| Handle<AccessorPair> pair(isolate->factory()->NewAccessorPair()); |
| pair->set(component, value); |
| value_handle = pair; |
| } |
| |
| // Add value to the dictionary without updating next enumeration index. |
| Handle<Dictionary> dict = DictionaryAddNoUpdateNextEnumerationIndex( |
| dictionary, key, value_handle, details, &entry); |
| // It is crucial to avoid dictionary reallocations because it may remove |
| // potential gaps in enumeration indices values that are necessary for |
| // inserting computed properties into right places in the enumeration order. |
| CHECK_EQ(*dict, *dictionary); |
| |
| DictionaryUpdateMaxNumberKey(dictionary, key); |
| |
| } else { |
| // Entry found, update it. |
| int enum_order = dictionary->DetailsAt(entry).dictionary_index(); |
| Object* existing_value = dictionary->ValueAt(entry); |
| if (value_kind == ClassBoilerplate::kData) { |
| // Computed value is a normal method. |
| if (existing_value->IsAccessorPair()) { |
| AccessorPair* current_pair = AccessorPair::cast(existing_value); |
| |
| int existing_getter_index = |
| GetExistingValueIndex(current_pair->getter()); |
| int existing_setter_index = |
| GetExistingValueIndex(current_pair->setter()); |
| if (existing_getter_index < key_index && |
| existing_setter_index < key_index) { |
| // Both getter and setter were defined before the computed method, |
| // so overwrite both. |
| PropertyDetails details(kData, DONT_ENUM, PropertyCellType::kNoCell, |
| enum_order); |
| dictionary->DetailsAtPut(entry, details); |
| dictionary->ValueAtPut(entry, value); |
| |
| } else { |
| if (existing_getter_index < key_index) { |
| DCHECK_LT(existing_setter_index, key_index); |
| // Getter was defined before the computed method and then it was |
| // overwritten by the current computed method which in turn was |
| // later overwritten by the setter method. So we clear the getter. |
| current_pair->set_getter(*isolate->factory()->null_value()); |
| |
| } else if (existing_setter_index < key_index) { |
| DCHECK_LT(existing_getter_index, key_index); |
| // Setter was defined before the computed method and then it was |
| // overwritten by the current computed method which in turn was |
| // later overwritten by the getter method. So we clear the setter. |
| current_pair->set_setter(*isolate->factory()->null_value()); |
| } |
| } |
| } else { |
| // Overwrite existing value if it was defined before the computed one. |
| int existing_value_index = Smi::ToInt(existing_value); |
| if (existing_value_index < key_index) { |
| PropertyDetails details(kData, DONT_ENUM, PropertyCellType::kNoCell, |
| enum_order); |
| dictionary->DetailsAtPut(entry, details); |
| dictionary->ValueAtPut(entry, value); |
| } |
| } |
| } else { |
| AccessorComponent component = value_kind == ClassBoilerplate::kGetter |
| ? ACCESSOR_GETTER |
| : ACCESSOR_SETTER; |
| if (existing_value->IsAccessorPair()) { |
| AccessorPair* current_pair = AccessorPair::cast(existing_value); |
| |
| int existing_component_index = |
| GetExistingValueIndex(current_pair->get(component)); |
| if (existing_component_index < key_index) { |
| current_pair->set(component, value); |
| } |
| |
| } else { |
| Handle<AccessorPair> pair(isolate->factory()->NewAccessorPair()); |
| pair->set(component, value); |
| PropertyDetails details(kAccessor, DONT_ENUM, |
| PropertyCellType::kNoCell); |
| dictionary->DetailsAtPut(entry, details); |
| dictionary->ValueAtPut(entry, *pair); |
| } |
| } |
| } |
| } |
| |
| } // namespace |
| |
| // Helper class that eases building of a properties, elements and computed |
| // properties templates. |
| class ObjectDescriptor { |
| public: |
| void IncComputedCount() { ++computed_count_; } |
| void IncPropertiesCount() { ++property_count_; } |
| void IncElementsCount() { ++element_count_; } |
| |
| bool HasDictionaryProperties() const { |
| return computed_count_ > 0 || property_count_ > kMaxNumberOfDescriptors; |
| } |
| |
| Handle<Object> properties_template() const { |
| return HasDictionaryProperties() |
| ? Handle<Object>::cast(properties_dictionary_template_) |
| : Handle<Object>::cast(descriptor_array_template_); |
| } |
| |
| Handle<NumberDictionary> elements_template() const { |
| return elements_dictionary_template_; |
| } |
| |
| Handle<FixedArray> computed_properties() const { |
| return computed_properties_; |
| } |
| |
| void CreateTemplates(Isolate* isolate, int slack) { |
| Factory* factory = isolate->factory(); |
| descriptor_array_template_ = factory->empty_descriptor_array(); |
| properties_dictionary_template_ = factory->empty_property_dictionary(); |
| if (property_count_ || HasDictionaryProperties() || slack) { |
| if (HasDictionaryProperties()) { |
| properties_dictionary_template_ = NameDictionary::New( |
| isolate, property_count_ + computed_count_ + slack); |
| } else { |
| descriptor_array_template_ = |
| DescriptorArray::Allocate(isolate, 0, property_count_ + slack); |
| } |
| } |
| elements_dictionary_template_ = |
| element_count_ || computed_count_ |
| ? NumberDictionary::New(isolate, element_count_ + computed_count_) |
| : factory->empty_slow_element_dictionary(); |
| |
| computed_properties_ = |
| computed_count_ |
| ? factory->NewFixedArray(computed_count_ * |
| ClassBoilerplate::kFullComputedEntrySize) |
| : factory->empty_fixed_array(); |
| |
| temp_handle_ = handle(Smi::kZero, isolate); |
| } |
| |
| void AddConstant(Handle<Name> name, Handle<Object> value, |
| PropertyAttributes attribs) { |
| bool is_accessor = value->IsAccessorInfo(); |
| DCHECK(!value->IsAccessorPair()); |
| if (HasDictionaryProperties()) { |
| PropertyKind kind = is_accessor ? i::kAccessor : i::kData; |
| PropertyDetails details(kind, attribs, PropertyCellType::kNoCell, |
| next_enumeration_index_++); |
| properties_dictionary_template_ = |
| DictionaryAddNoUpdateNextEnumerationIndex( |
| properties_dictionary_template_, name, value, details); |
| } else { |
| Descriptor d = is_accessor |
| ? Descriptor::AccessorConstant(name, value, attribs) |
| : Descriptor::DataConstant(name, value, attribs); |
| descriptor_array_template_->Append(&d); |
| } |
| } |
| |
| void AddNamedProperty(Isolate* isolate, Handle<Name> name, |
| ClassBoilerplate::ValueKind value_kind, |
| int value_index) { |
| Smi* value = Smi::FromInt(value_index); |
| if (HasDictionaryProperties()) { |
| UpdateNextEnumerationIndex(value_index); |
| AddToDictionaryTemplate(isolate, properties_dictionary_template_, name, |
| value_index, value_kind, value); |
| } else { |
| *temp_handle_.location() = value; |
| AddToDescriptorArrayTemplate(isolate, descriptor_array_template_, name, |
| value_kind, temp_handle_); |
| } |
| } |
| |
| void AddIndexedProperty(Isolate* isolate, uint32_t element, |
| ClassBoilerplate::ValueKind value_kind, |
| int value_index) { |
| Smi* value = Smi::FromInt(value_index); |
| AddToDictionaryTemplate(isolate, elements_dictionary_template_, element, |
| value_index, value_kind, value); |
| } |
| |
| void AddComputed(ClassBoilerplate::ValueKind value_kind, int key_index) { |
| int value_index = key_index + 1; |
| UpdateNextEnumerationIndex(value_index); |
| |
| int flags = EncodeComputedEntry(value_kind, key_index); |
| computed_properties_->set(current_computed_index_++, Smi::FromInt(flags)); |
| } |
| |
| void UpdateNextEnumerationIndex(int value_index) { |
| int next_index = ComputeEnumerationIndex(value_index); |
| DCHECK_LT(next_enumeration_index_, next_index); |
| next_enumeration_index_ = next_index; |
| } |
| |
| void Finalize(Isolate* isolate) { |
| if (HasDictionaryProperties()) { |
| properties_dictionary_template_->SetNextEnumerationIndex( |
| next_enumeration_index_); |
| |
| isolate->heap()->RightTrimFixedArray( |
| *computed_properties_, |
| computed_properties_->length() - current_computed_index_); |
| } else { |
| DCHECK(descriptor_array_template_->IsSortedNoDuplicates()); |
| } |
| } |
| |
| private: |
| int property_count_ = 0; |
| int next_enumeration_index_ = PropertyDetails::kInitialIndex; |
| int element_count_ = 0; |
| int computed_count_ = 0; |
| int current_computed_index_ = 0; |
| |
| Handle<DescriptorArray> descriptor_array_template_; |
| Handle<NameDictionary> properties_dictionary_template_; |
| Handle<NumberDictionary> elements_dictionary_template_; |
| Handle<FixedArray> computed_properties_; |
| // This temporary handle is used for storing to descriptor array. |
| Handle<Object> temp_handle_; |
| }; |
| |
| void ClassBoilerplate::AddToPropertiesTemplate( |
| Isolate* isolate, Handle<NameDictionary> dictionary, Handle<Name> name, |
| int key_index, ClassBoilerplate::ValueKind value_kind, Object* value) { |
| AddToDictionaryTemplate(isolate, dictionary, name, key_index, value_kind, |
| value); |
| } |
| |
| void ClassBoilerplate::AddToElementsTemplate( |
| Isolate* isolate, Handle<NumberDictionary> dictionary, uint32_t key, |
| int key_index, ClassBoilerplate::ValueKind value_kind, Object* value) { |
| AddToDictionaryTemplate(isolate, dictionary, key, key_index, value_kind, |
| value); |
| } |
| |
| Handle<ClassBoilerplate> ClassBoilerplate::BuildClassBoilerplate( |
| Isolate* isolate, ClassLiteral* expr) { |
| Factory* factory = isolate->factory(); |
| ObjectDescriptor static_desc; |
| ObjectDescriptor instance_desc; |
| |
| for (int i = 0; i < expr->properties()->length(); i++) { |
| ClassLiteral::Property* property = expr->properties()->at(i); |
| ObjectDescriptor& desc = |
| property->is_static() ? static_desc : instance_desc; |
| if (property->is_computed_name()) { |
| desc.IncComputedCount(); |
| } else { |
| if (property->key()->AsLiteral()->IsPropertyName()) { |
| desc.IncPropertiesCount(); |
| } else { |
| desc.IncElementsCount(); |
| } |
| } |
| } |
| |
| // |
| // Initialize class object template. |
| // |
| static_desc.CreateTemplates(isolate, kMinimumClassPropertiesCount); |
| Handle<DescriptorArray> class_function_descriptors( |
| isolate->native_context()->class_function_map()->instance_descriptors(), |
| isolate); |
| STATIC_ASSERT(JSFunction::kLengthDescriptorIndex == 0); |
| { |
| // Add length_accessor. |
| PropertyAttributes attribs = |
| static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY); |
| static_desc.AddConstant(factory->length_string(), |
| factory->function_length_accessor(), attribs); |
| } |
| { |
| // Add prototype_accessor. |
| PropertyAttributes attribs = |
| static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY); |
| static_desc.AddConstant(factory->prototype_string(), |
| factory->function_prototype_accessor(), attribs); |
| } |
| if (FunctionLiteral::NeedsHomeObject(expr->constructor())) { |
| PropertyAttributes attribs = |
| static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY); |
| Handle<Object> value( |
| Smi::FromInt(ClassBoilerplate::kPrototypeArgumentIndex), isolate); |
| static_desc.AddConstant(factory->home_object_symbol(), value, attribs); |
| } |
| { |
| Handle<Smi> start_position(Smi::FromInt(expr->start_position()), isolate); |
| Handle<Smi> end_position(Smi::FromInt(expr->end_position()), isolate); |
| Handle<Tuple2> class_positions = |
| factory->NewTuple2(start_position, end_position, NOT_TENURED); |
| static_desc.AddConstant(factory->class_positions_symbol(), class_positions, |
| DONT_ENUM); |
| } |
| |
| // |
| // Initialize prototype object template. |
| // |
| instance_desc.CreateTemplates(isolate, kMinimumPrototypePropertiesCount); |
| { |
| Handle<Object> value( |
| Smi::FromInt(ClassBoilerplate::kConstructorArgumentIndex), isolate); |
| instance_desc.AddConstant(factory->constructor_string(), value, DONT_ENUM); |
| } |
| |
| // |
| // Fill in class boilerplate. |
| // |
| int dynamic_argument_index = ClassBoilerplate::kFirstDynamicArgumentIndex; |
| |
| for (int i = 0; i < expr->properties()->length(); i++) { |
| ClassLiteral::Property* property = expr->properties()->at(i); |
| |
| ClassBoilerplate::ValueKind value_kind; |
| switch (property->kind()) { |
| case ClassLiteral::Property::METHOD: |
| value_kind = ClassBoilerplate::kData; |
| break; |
| case ClassLiteral::Property::GETTER: |
| value_kind = ClassBoilerplate::kGetter; |
| break; |
| case ClassLiteral::Property::SETTER: |
| value_kind = ClassBoilerplate::kSetter; |
| break; |
| case ClassLiteral::Property::FIELD: |
| if (property->is_computed_name()) { |
| ++dynamic_argument_index; |
| } |
| continue; |
| } |
| |
| ObjectDescriptor& desc = |
| property->is_static() ? static_desc : instance_desc; |
| if (property->is_computed_name()) { |
| int computed_name_index = dynamic_argument_index; |
| dynamic_argument_index += 2; // Computed name and value indices. |
| desc.AddComputed(value_kind, computed_name_index); |
| continue; |
| } |
| int value_index = dynamic_argument_index++; |
| |
| Literal* key_literal = property->key()->AsLiteral(); |
| uint32_t index; |
| if (key_literal->AsArrayIndex(&index)) { |
| desc.AddIndexedProperty(isolate, index, value_kind, value_index); |
| |
| } else { |
| Handle<String> name = key_literal->AsRawPropertyName()->string(); |
| DCHECK(name->IsInternalizedString()); |
| desc.AddNamedProperty(isolate, name, value_kind, value_index); |
| } |
| } |
| |
| // Add name accessor to the class object if necessary. |
| bool install_class_name_accessor = false; |
| if (!expr->has_name_static_property() && |
| expr->constructor()->has_shared_name()) { |
| if (static_desc.HasDictionaryProperties()) { |
| // Install class name accessor if necessary during class literal |
| // instantiation. |
| install_class_name_accessor = true; |
| } else { |
| // Set class name accessor if the "name" method was not added yet. |
| PropertyAttributes attribs = |
| static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY); |
| static_desc.AddConstant(factory->name_string(), |
| factory->function_name_accessor(), attribs); |
| } |
| } |
| |
| static_desc.Finalize(isolate); |
| instance_desc.Finalize(isolate); |
| |
| Handle<ClassBoilerplate> class_boilerplate = |
| Handle<ClassBoilerplate>::cast(factory->NewFixedArray(kBoileplateLength)); |
| |
| class_boilerplate->set_flags(0); |
| class_boilerplate->set_install_class_name_accessor( |
| install_class_name_accessor); |
| class_boilerplate->set_arguments_count(dynamic_argument_index); |
| |
| class_boilerplate->set_static_properties_template( |
| *static_desc.properties_template()); |
| class_boilerplate->set_static_elements_template( |
| *static_desc.elements_template()); |
| class_boilerplate->set_static_computed_properties( |
| *static_desc.computed_properties()); |
| |
| class_boilerplate->set_instance_properties_template( |
| *instance_desc.properties_template()); |
| class_boilerplate->set_instance_elements_template( |
| *instance_desc.elements_template()); |
| class_boilerplate->set_instance_computed_properties( |
| *instance_desc.computed_properties()); |
| |
| return class_boilerplate; |
| } |
| |
| } // namespace internal |
| } // namespace v8 |
