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LibJS: Add inline caching for adding new own properties to objects

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We already had IC support in PutById for the following cases:
- Changing an existing own property
- Calling a setter located in the prototype chain

This was enough to speed up code where structurally identical objects
(same shape) are processed in a loop:
```js
const arr = [{ a: 1 }, { a: 2 }, { a: 3 }];
for (let obj of arr) {
    obj.a += 1;
}
```

However, creating structurally identical objects in a loop was still
slow:
```js
for (let i = 0; i < 10_000_000; i++) {
    const o = {};
    o.a = 1;
    o.b = 2;
    o.c = 3;
}
```

This change addresses that by adding a new IC type that caches both the
source and target shapes, allowing property additions to be fast-pathed
by directly jumping to the shape that already includes the new property.
This commit is contained in:
Aliaksandr Kalenik
2025-09-15 17:23:39 +02:00
committed by Andreas Kling
parent a54215c07d
commit d45f8a3081
Notes: github-actions[bot] 2025-09-17 10:45:37 +00:00 
Author: https://github.com/kalenikaliaksandr
Commit: https://github.com/LadybirdBrowser/ladybird/commit/d45f8a30817
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/6204
21 changed files with 162 additions and 75 deletions
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4
Libraries/LibJS/Runtime/ModuleNamespaceObject.h
View File

@@ -26,8 +26,8 @@ public:
virtual ThrowCompletionOr<Optional<PropertyDescriptor>> internal_get_own_property(PropertyKey const&) const override;
virtual ThrowCompletionOr<bool> internal_define_own_property(PropertyKey const&, PropertyDescriptor&, Optional<PropertyDescriptor>* precomputed_get_own_property = nullptr) override;
virtual ThrowCompletionOr<bool> internal_has_property(PropertyKey const&) const override;
virtual ThrowCompletionOr<Value> internal_get(PropertyKey const&, Value receiver, CacheablePropertyMetadata* = nullptr, PropertyLookupPhase = PropertyLookupPhase::OwnProperty) const override;
virtual ThrowCompletionOr<bool> internal_set(PropertyKey const&, Value value, Value receiver, CacheablePropertyMetadata*, PropertyLookupPhase) override;
virtual ThrowCompletionOr<Value> internal_get(PropertyKey const&, Value receiver, CacheableGetPropertyMetadata* = nullptr, PropertyLookupPhase = PropertyLookupPhase::OwnProperty) const override;
virtual ThrowCompletionOr<bool> internal_set(PropertyKey const&, Value value, Value receiver, CacheableSetPropertyMetadata*, PropertyLookupPhase) override;
virtual ThrowCompletionOr<bool> internal_delete(PropertyKey const&) override;
virtual ThrowCompletionOr<GC::RootVector<Value>> internal_own_property_keys() const override;
virtual void initialize(Realm&) override;