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646457099c
With this change, `GetIterator` no longer GC-allocates an
`IteratorRecord`. Instead, it stores the iterator record fields in
bytecode registers. This avoids per-iteration allocations in patterns
like: `for (let [x] of array) {}`.
`IteratorRecord` now inherits from `IteratorRecordImpl`, which holds the
iteration state. This allows the existing iteration helpers
(`iterator_next()`, `iterator_step()`, etc.) operate on both the
GC-allocated and the register-backed forms.
Microbenchmarks:
1.1x array-destructuring-assignment-rest.js
1.226x array-destructuring-assignment.js
41 lines
1 KiB
C++
41 lines
1 KiB
C++
/*
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* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <LibJS/Runtime/Iterator.h>
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#include <LibJS/Runtime/Map.h>
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#include <LibJS/Runtime/Object.h>
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namespace JS {
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class MapIterator final : public Object
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, public BuiltinIterator {
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JS_OBJECT(MapIterator, Object);
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GC_DECLARE_ALLOCATOR(MapIterator);
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public:
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static GC::Ref<MapIterator> create(Realm&, Map& map, Object::PropertyKind iteration_kind);
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virtual ~MapIterator() override = default;
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BuiltinIterator* as_builtin_iterator_if_next_is_not_redefined(Value next_method) override;
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ThrowCompletionOr<void> next(VM&, bool& done, Value& value) override;
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private:
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friend class MapIteratorPrototype;
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explicit MapIterator(Map& map, Object::PropertyKind iteration_kind, Object& prototype);
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virtual void visit_edges(Cell::Visitor&) override;
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GC::Ref<Map> m_map;
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bool m_done { false };
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Object::PropertyKind m_iteration_kind;
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Map::ConstIterator m_iterator;
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};
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}
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