mirror of
https://github.com/RGBCube/serenity
synced 2025-10-31 17:32:44 +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);
67 lines
2.2 KiB
C++
67 lines
2.2 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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#include <LibJS/Runtime/GlobalObject.h>
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#include <LibJS/Runtime/Iterator.h>
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#include <LibJS/Runtime/IteratorHelper.h>
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#include <LibJS/Runtime/Realm.h>
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namespace JS {
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JS_DEFINE_ALLOCATOR(IteratorHelper);
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ThrowCompletionOr<NonnullGCPtr<IteratorHelper>> IteratorHelper::create(Realm& realm, NonnullGCPtr<IteratorRecord> underlying_iterator, Closure closure, Optional<AbruptClosure> abrupt_closure)
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{
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return realm.heap().allocate<IteratorHelper>(realm, realm, realm.intrinsics().iterator_helper_prototype(), move(underlying_iterator), move(closure), move(abrupt_closure));
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}
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IteratorHelper::IteratorHelper(Realm& realm, Object& prototype, NonnullGCPtr<IteratorRecord> underlying_iterator, Closure closure, Optional<AbruptClosure> abrupt_closure)
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: GeneratorObject(realm, prototype, realm.vm().running_execution_context().copy(), "Iterator Helper"sv)
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, m_underlying_iterator(move(underlying_iterator))
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, m_closure(move(closure))
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, m_abrupt_closure(move(abrupt_closure))
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{
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}
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void IteratorHelper::visit_edges(Visitor& visitor)
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{
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Base::visit_edges(visitor);
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visitor.visit(m_underlying_iterator);
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}
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Value IteratorHelper::result(Value value)
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{
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set_generator_state(value.is_undefined() ? GeneratorState::Completed : GeneratorState::SuspendedYield);
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return value;
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}
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ThrowCompletionOr<Value> IteratorHelper::close_result(VM& vm, Completion completion)
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{
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set_generator_state(GeneratorState::Completed);
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return *TRY(iterator_close(vm, underlying_iterator(), move(completion)));
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}
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ThrowCompletionOr<Value> IteratorHelper::execute(VM& vm, JS::Completion const& completion)
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{
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ScopeGuard guard { [&] { vm.pop_execution_context(); } };
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if (completion.is_abrupt()) {
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if (m_abrupt_closure.has_value())
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return (*m_abrupt_closure)(vm, *this, completion);
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return close_result(vm, completion);
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}
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auto result_value = m_closure(vm, *this);
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if (result_value.is_throw_completion()) {
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set_generator_state(GeneratorState::Completed);
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return result_value;
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}
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return create_iterator_result_object(vm, result(result_value.release_value()), generator_state() == GeneratorState::Completed);
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}
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}
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