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);
33 lines
1 KiB
C++
33 lines
1 KiB
C++
/*
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* Copyright (c) 2021, David Tuin <davidot@serenityos.org>
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* Copyright (c) 2022-2023, Linus Groh <linusg@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/Runtime/AsyncFromSyncIterator.h>
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#include <LibJS/Runtime/AsyncFromSyncIteratorPrototype.h>
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#include <LibJS/Runtime/GlobalObject.h>
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namespace JS {
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JS_DEFINE_ALLOCATOR(AsyncFromSyncIterator);
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NonnullGCPtr<AsyncFromSyncIterator> AsyncFromSyncIterator::create(Realm& realm, NonnullGCPtr<IteratorRecord> sync_iterator_record)
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{
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return realm.heap().allocate<AsyncFromSyncIterator>(realm, realm, sync_iterator_record);
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}
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AsyncFromSyncIterator::AsyncFromSyncIterator(Realm& realm, NonnullGCPtr<IteratorRecord> sync_iterator_record)
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: Object(ConstructWithPrototypeTag::Tag, realm.intrinsics().async_from_sync_iterator_prototype())
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, m_sync_iterator_record(sync_iterator_record)
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{
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}
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void AsyncFromSyncIterator::visit_edges(Cell::Visitor& visitor)
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{
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Base::visit_edges(visitor);
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visitor.visit(m_sync_iterator_record);
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}
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}
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