Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: c9740e5b2bb94d45875c64d3ee4da528f534aeea
https://github.com/WebKit/WebKit/commit/c9740e5b2bb94d45875c64d3ee4da528f534aeea
Author: Sosuke Suzuki <[email protected]>
Date: 2026-08-24 (Mon, 24 Aug 2026)
Changed paths:
A JSTests/microbenchmarks/object-rest-clone.js
A JSTests/stress/object-rest-clone.js
M Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp
Log Message:
-----------
[JSC] Use `objectCloneFast` for object rest destructuring in
`@copyDataProperties`
https://bugs.webkit.org/show_bug.cgi?id=322374
Reviewed by Yusuke Suzuki.
Object rest destructuring (`const { ...rest } = object`) creates an empty
object and
calls @copyDataProperties, which replays the source's shape one property at a
time
via putOwnDataPropertyBatching even when nothing is excluded. This is the
situation
319645@main fixed for Object.assign's batching path.
Try objectCloneFast before enumerating properties when the excluded set is
empty.
The preconditions of the fast enumeration block already satisfy what
objectCloneFast
requires, and a non-empty target fails its first check.
Baseline Patched
object-rest-clone 0.8409+-0.0355 ^
0.5708+-0.0369 ^ definitely 1.4733x faster
Tests: JSTests/microbenchmarks/object-rest-clone.js
JSTests/stress/object-rest-clone.js
* JSTests/microbenchmarks/object-rest-clone.js: Added.
* JSTests/stress/object-rest-clone.js: Added.
(shouldBe):
(shouldBeArray):
(makeState):
(restOnly):
(restParameter):
* Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp:
(JSC::JSC_DEFINE_HOST_FUNCTION):
Canonical link: https://commits.webkit.org/319745@main
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