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https://github.com/LadybirdBrowser/ladybird.git
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4c789ac689
- Create less GC pressure by making each `await` in async function skip
iteration result object allocation.
- Skip uncached `Object::get()` calls to extract `value` and `done` from
the iteration result object.
With this change, following function goes 30% faster on my computer:
```js
(async () => {
const resolved = Promise.resolve();
for (let i = 0; i < 5_000_000; i++) {
await resolved;
}
})();
```
50 lines
1.6 KiB
C++
50 lines
1.6 KiB
C++
/*
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* Copyright (c) 2023, Tim Flynn <trflynn89@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 <LibGC/Function.h>
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#include <LibJS/Runtime/Completion.h>
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#include <LibJS/Runtime/GeneratorObject.h>
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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 IteratorHelper final : public GeneratorObject {
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JS_OBJECT(IteratorHelper, GeneratorObject);
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GC_DECLARE_ALLOCATOR(IteratorHelper);
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public:
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using Closure = GC::Function<ThrowCompletionOr<Value>(VM&, IteratorHelper&)>;
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using AbruptClosure = GC::Function<ThrowCompletionOr<Value>(VM&, IteratorHelper&, Completion const&)>;
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static ThrowCompletionOr<GC::Ref<IteratorHelper>> create(Realm&, GC::Ref<IteratorRecord>, GC::Ref<Closure>, GC::Ptr<AbruptClosure> = {});
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IteratorRecord& underlying_iterator() { return m_underlying_iterator; }
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IteratorRecord const& underlying_iterator() const { return m_underlying_iterator; }
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size_t counter() const { return m_counter; }
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void increment_counter() { ++m_counter; }
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Value result(Value);
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ThrowCompletionOr<Value> close_result(VM&, Completion);
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private:
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IteratorHelper(Realm&, Object& prototype, GC::Ref<IteratorRecord>, GC::Ref<Closure>, GC::Ptr<AbruptClosure>);
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virtual void visit_edges(Visitor&) override;
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virtual ThrowCompletionOr<IterationResult> execute(VM&, JS::Completion const& completion) override;
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GC::Ref<IteratorRecord> m_underlying_iterator; // [[UnderlyingIterator]]
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GC::Ref<Closure> m_closure;
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GC::Ptr<AbruptClosure> m_abrupt_closure;
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size_t m_counter { 0 };
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bool m_done { false };
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};
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}
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