89 lines
3.3 KiB
C++
89 lines
3.3 KiB
C++
/*
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* Copyright (c) 2021-2023, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibJS/Bytecode/CommonImplementations.h>
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#include <LibJS/Bytecode/Interpreter.h>
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namespace JS::Bytecode {
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ThrowCompletionOr<NonnullGCPtr<Object>> base_object_for_get(Bytecode::Interpreter& interpreter, Value base_value)
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{
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auto& vm = interpreter.vm();
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if (base_value.is_object())
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return base_value.as_object();
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// OPTIMIZATION: For various primitives we can avoid actually creating a new object for them.
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if (base_value.is_string())
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return vm.current_realm()->intrinsics().string_prototype();
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if (base_value.is_number())
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return vm.current_realm()->intrinsics().number_prototype();
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if (base_value.is_boolean())
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return vm.current_realm()->intrinsics().boolean_prototype();
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return base_value.to_object(vm);
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}
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ThrowCompletionOr<Value> get_by_id(Bytecode::Interpreter& interpreter, IdentifierTableIndex property, Value base_value, Value this_value, u32 cache_index)
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{
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auto& vm = interpreter.vm();
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auto const& name = interpreter.current_executable().get_identifier(property);
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auto& cache = interpreter.current_executable().property_lookup_caches[cache_index];
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if (base_value.is_string()) {
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auto string_value = TRY(base_value.as_string().get(vm, name));
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if (string_value.has_value())
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return *string_value;
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}
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auto base_obj = TRY(base_object_for_get(interpreter, base_value));
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// OPTIMIZATION: If the shape of the object hasn't changed, we can use the cached property offset.
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// NOTE: Unique shapes don't change identity, so we compare their serial numbers instead.
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auto& shape = base_obj->shape();
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if (&shape == cache.shape
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&& (!shape.is_unique() || shape.unique_shape_serial_number() == cache.unique_shape_serial_number)) {
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return base_obj->get_direct(cache.property_offset.value());
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}
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CacheablePropertyMetadata cacheable_metadata;
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auto value = TRY(base_obj->internal_get(name, this_value, &cacheable_metadata));
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if (cacheable_metadata.type == CacheablePropertyMetadata::Type::OwnProperty) {
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cache.shape = shape;
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cache.property_offset = cacheable_metadata.property_offset.value();
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cache.unique_shape_serial_number = shape.unique_shape_serial_number();
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}
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return value;
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}
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ThrowCompletionOr<Value> get_by_value(Bytecode::Interpreter& interpreter, Value base_value, Value property_key_value)
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{
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auto& vm = interpreter.vm();
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auto object = TRY(base_object_for_get(interpreter, base_value));
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// OPTIMIZATION: Fast path for simple Int32 indexes in array-like objects.
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if (property_key_value.is_int32()
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&& property_key_value.as_i32() >= 0
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&& !object->may_interfere_with_indexed_property_access()
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&& object->indexed_properties().has_index(property_key_value.as_i32())) {
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auto value = object->indexed_properties().get(property_key_value.as_i32())->value;
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if (!value.is_accessor())
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return value;
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}
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auto property_key = TRY(property_key_value.to_property_key(vm));
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if (base_value.is_string()) {
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auto string_value = TRY(base_value.as_string().get(vm, property_key));
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if (string_value.has_value())
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return *string_value;
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}
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return TRY(object->internal_get(property_key, base_value));
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}
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}
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