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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
1.1 KiB
C++
41 lines
1.1 KiB
C++
/*
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* Copyright (c) 2020, Matthew Olsson <mattco@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/Object.h>
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namespace JS {
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class ArrayIterator final : public Object
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, public BuiltinIterator {
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JS_OBJECT(ArrayIterator, Object);
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GC_DECLARE_ALLOCATOR(ArrayIterator);
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public:
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static GC::Ref<ArrayIterator> create(Realm&, Value array, Object::PropertyKind iteration_kind);
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virtual ~ArrayIterator() 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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ArrayIterator(Value array, Object::PropertyKind iteration_kind, Object& prototype);
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virtual bool is_array_iterator() const override { return true; }
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virtual void visit_edges(Cell::Visitor&) override;
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Value m_array;
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Object::PropertyKind m_iteration_kind;
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size_t m_index { 0 };
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};
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template<>
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inline bool Object::fast_is<ArrayIterator>() const { return is_array_iterator(); }
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}
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