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
This commit is contained in:
Andreas Kling 2025-05-04 16:00:13 +02:00 committed by Andreas Kling
parent 71665fa504
commit 183c847c80
Notes: github-actions[bot] 2025-05-05 13:22:41 +00:00
18 changed files with 93 additions and 39 deletions

View file

@ -28,7 +28,7 @@ public:
virtual JS::ThrowCompletionOr<Optional<JS::PropertyDescriptor>> internal_get_own_property(JS::PropertyKey const&) const override;
virtual JS::ThrowCompletionOr<bool> internal_define_own_property(JS::PropertyKey const&, JS::PropertyDescriptor const&, Optional<JS::PropertyDescriptor>* precomputed_get_own_property = nullptr) override;
virtual JS::ThrowCompletionOr<JS::Value> internal_get(JS::PropertyKey const&, JS::Value receiver, JS::CacheablePropertyMetadata*, PropertyLookupPhase) const override;
virtual JS::ThrowCompletionOr<bool> internal_set(JS::PropertyKey const&, JS::Value value, JS::Value receiver, JS::CacheablePropertyMetadata*) override;
virtual JS::ThrowCompletionOr<bool> internal_set(JS::PropertyKey const&, JS::Value value, JS::Value receiver, JS::CacheablePropertyMetadata*, PropertyLookupPhase) override;
virtual JS::ThrowCompletionOr<bool> internal_delete(JS::PropertyKey const&) override;
virtual JS::ThrowCompletionOr<GC::RootVector<JS::Value>> internal_own_property_keys() const override;