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ladybird/Libraries/LibJS/Runtime/ArgumentsObject.h
Andreas Kling 183c847c80 LibJS: Cache PutById to setters in the prototype chain
This is *extremely* common on the web, but barely shows up at all in
JavaScript benchmarks.

A typical example is setting Element.innerHTML on a HTMLDivElement.
HTMLDivElement doesn't have innerHTML, so it has to travel up the
prototype chain until it finds it.

Before this change, we didn't cache this at all, so we had to travel
the prototype chain every time a setter like this was used.

We now use the same mechanism we already had for GetBydId and cache
PutById setter accesses in the prototype chain as well.

1.74x speedup on MicroBench/setter-in-prototype-chain.js
2025-05-05 15:21:43 +02:00

43 lines
1.5 KiB
C++

/*
* Copyright (c) 2021, Andreas Kling <andreas@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <LibJS/Runtime/Completion.h>
#include <LibJS/Runtime/Environment.h>
#include <LibJS/Runtime/Object.h>
namespace JS {
class ArgumentsObject final : public Object {
JS_OBJECT(ArgumentsObject, Object);
GC_DECLARE_ALLOCATOR(ArgumentsObject);
public:
virtual void initialize(Realm&) override;
virtual ~ArgumentsObject() override = default;
Environment& environment() { return m_environment; }
virtual ThrowCompletionOr<Optional<PropertyDescriptor>> internal_get_own_property(PropertyKey const&) const override;
virtual ThrowCompletionOr<bool> internal_define_own_property(PropertyKey const&, PropertyDescriptor const&, Optional<PropertyDescriptor>* precomputed_get_own_property = nullptr) override;
virtual ThrowCompletionOr<Value> internal_get(PropertyKey const&, Value receiver, CacheablePropertyMetadata*, PropertyLookupPhase) const override;
virtual ThrowCompletionOr<bool> internal_set(PropertyKey const&, Value value, Value receiver, CacheablePropertyMetadata*, PropertyLookupPhase) override;
virtual ThrowCompletionOr<bool> internal_delete(PropertyKey const&) override;
// [[ParameterMap]]
Object& parameter_map() { return *m_parameter_map; }
private:
ArgumentsObject(Realm&, Environment&);
virtual void visit_edges(Cell::Visitor&) override;
GC::Ref<Environment> m_environment;
GC::Ptr<Object> m_parameter_map;
};
}