mirror of
https://github.com/RGBCube/serenity
synced 2025-10-31 19:12:43 +00:00
4699c81fc1
This patch makes IteratorRecord an Object. Although it's not exposed to
author code, this does allow us to store it in a VM register.
Now that we can store it in a VM register, we don't need to convert it
back and forth between IteratorRecord and Object when accessing it from
bytecode.
The big win here is avoiding 3 [[Get]] accesses on every iteration step
of for..of loops. There are also a bunch of smaller efficiencies gained.
20% speed-up on this microbenchmark:
function go(a) {
for (const p of a) {
}
}
const a = [];
a.length = 1_000_000;
go(a);
49 lines
1.5 KiB
C++
49 lines
1.5 KiB
C++
/*
|
|
* Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <LibJS/Runtime/Completion.h>
|
|
#include <LibJS/Runtime/GeneratorObject.h>
|
|
#include <LibJS/Runtime/Iterator.h>
|
|
#include <LibJS/Runtime/Object.h>
|
|
#include <LibJS/SafeFunction.h>
|
|
|
|
namespace JS {
|
|
|
|
class IteratorHelper final : public GeneratorObject {
|
|
JS_OBJECT(IteratorHelper, GeneratorObject);
|
|
JS_DECLARE_ALLOCATOR(IteratorHelper);
|
|
|
|
public:
|
|
using Closure = JS::SafeFunction<ThrowCompletionOr<Value>(VM&, IteratorHelper&)>;
|
|
using AbruptClosure = JS::SafeFunction<ThrowCompletionOr<Value>(VM&, IteratorHelper&, Completion const&)>;
|
|
|
|
static ThrowCompletionOr<NonnullGCPtr<IteratorHelper>> create(Realm&, NonnullGCPtr<IteratorRecord>, Closure, Optional<AbruptClosure> = {});
|
|
|
|
IteratorRecord const& underlying_iterator() const { return m_underlying_iterator; }
|
|
|
|
size_t counter() const { return m_counter; }
|
|
void increment_counter() { ++m_counter; }
|
|
|
|
Value result(Value);
|
|
ThrowCompletionOr<Value> close_result(VM&, Completion);
|
|
|
|
private:
|
|
IteratorHelper(Realm&, Object& prototype, NonnullGCPtr<IteratorRecord>, Closure, Optional<AbruptClosure>);
|
|
|
|
virtual void visit_edges(Visitor&) override;
|
|
virtual ThrowCompletionOr<Value> execute(VM&, JS::Completion const& completion) override;
|
|
|
|
NonnullGCPtr<IteratorRecord> m_underlying_iterator; // [[UnderlyingIterator]]
|
|
Closure m_closure;
|
|
Optional<AbruptClosure> m_abrupt_closure;
|
|
|
|
size_t m_counter { 0 };
|
|
bool m_done { false };
|
|
};
|
|
|
|
}
|