Flip Intl, Temporal and %AsyncFromSyncIteratorPrototype% to builtin shapes#2597
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…hapes; escalate obsolete Generators flag The three remaining generator-emitted dictionary hosts whose members became expressible with Factory slots (sebastienros#2590): Intl (10 intrinsic refs + 2 functions), Temporal (9 intrinsic refs) and %AsyncFromSyncIteratorPrototype% (3 functions). Intl cold-start allocations drop ~1.1 KB per fresh-engine format call (-4.3%); engine construction is unaffected (hosts are lazy). Audited and skipped: RegExpConstructor (21 hand-rolled legacy accessors like $1-$9 would need instance slots; low value), JsSegments (per-call instance, no representative traffic). Math/JSON/Reflect/Atomics/Generator prototypes already use BuiltinShapeObject. Rider: ExperimentalFeature.Generators [Obsolete] escalated to error: true (flag has been a no-op; removal candidate for next major). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01S2U2y9voMQV9rvCkYeQbka
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Re-run after the builtin-shapes rollout and the 2026-07 performance campaign (#2580-#2597). Highlights vs the 4.11.0 refresh: minimal script -47% time / -45% allocation (prepared execution now under a microsecond), evaluation -33% allocation, stopwatch-modern -22% (ahead of NiL.JS, 1.13x behind Jurassic, from 1.44x), object-string -14%, string-base64 -12% (taking the lead from NiL.JS), object-array -11%. Competitor versions unchanged; their rows served as thermal canaries. Claude-Session: https://claude.ai/code/session_01S2U2y9voMQV9rvCkYeQbka Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
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Flip Intl, Temporal and %AsyncFromSyncIteratorPrototype% to builtin shapes
Completes the host sweep for the builtin-shape system: after #2590 made intrinsic references and throwers expressible as Factory slots, three generator-emitted hosts were still on the dictionary path for no remaining reason:
Intl— 10 lazy intrinsic references (Collator … Segmenter) +getCanonicalLocales/supportedValuesOf+@@toStringTagTemporal— 9 lazy intrinsic references +@@toStringTag%AsyncFromSyncIteratorPrototype%—next/return/throwEach now gets
[JsObject(UseShape = true)]: process-shared layout, per-realm descriptor array, no per-realmPropertyDictionary.Results (BenchmarkDotNet default jobs)
IntlColdStartBenchmark(fresh engine per op): −1.07…−1.08 KB allocated per row (−4.3%) across all five benchmarks, time neutral.EngineConstructionBenchmarkbyte-identical — these hosts are lazily initialized, so engine construction never touches them.Audited and skipped
RegExpConstructor: its Initialize hand-rolls 21 Annex B legacy accessors ($1–$9,$`,$&, …) via rawSetProperty; a flip would need an instance slot per accessor. Low value for the churn — left on the dictionary path with this note.JsSegments: per-call instance (returned byIntl.Segmenter.prototype.segment), not a per-realm singleton, and no representative workload traffic.Math/JSON/Reflect/Atomics/GeneratorPrototype/AsyncGeneratorPrototype/TemporalNowalready useBuiltinShapeObjectstorage — nothing to do.Rider
ExperimentalFeature.Generators[Obsolete]escalated toerror: true— the flag has been a no-op since generators became fully supported; escalation stages its removal for the next major. No in-repo consumers;Jint.Tests.PublicInterfacegreen after the change.Testing
Jint.Tests,Jint.Tests.PublicInterface,Jint.Tests.SourceGeneratorsgreenObject.getOwnPropertyNames(Intl)/(Temporal)key order identical to the dictionary path; formatters construct and format;@@toStringTagintact🤖 Generated with Claude Code
https://claude.ai/code/session_01S2U2y9voMQV9rvCkYeQbka