Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: cab8cdc40a6f3ab6e3943053356f3cd21a2d9e81
https://github.com/WebKit/WebKit/commit/cab8cdc40a6f3ab6e3943053356f3cd21a2d9e81
Author: Sosuke Suzuki <[email protected]>
Date: 2026-06-29 (Mon, 29 Jun 2026)
Changed paths:
A JSTests/microbenchmarks/regexp-prototype-flags-getter.js
A JSTests/stress/regexp-flags-getter-fast-path.js
M Source/JavaScriptCore/runtime/RegExpPrototype.cpp
Log Message:
-----------
[JSC] Add fast path for `RegExp#flags` getter
https://bugs.webkit.org/show_bug.cgi?id=318008
Reviewed by Yusuke Suzuki.
Every read of RegExp.prototype.flags performs eight generic property gets on the
receiver, each landing in a host getter on RegExp.prototype, even when nothing
is
overridden.
Add a fast path that builds the flags string directly from the RegExp's flag
bits
when the receiver is an unmodified RegExpObject covered by
regExpPrimordialPropertiesWatchpointSet.
Baseline Patched
regexp-prototype-flags-getter 328.2361+-8.0599 ^ 32.6714+-0.8326
^ definitely 10.0466x faster
Tests: JSTests/microbenchmarks/regexp-prototype-flags-getter.js
JSTests/stress/regexp-flags-getter-fast-path.js
* JSTests/microbenchmarks/regexp-prototype-flags-getter.js: Added.
* JSTests/stress/regexp-flags-getter-fast-path.js: Added.
(shouldBe):
(get global):
(PlainSubclass):
(OverridingSubclass.prototype.get global):
(OverridingSubclass):
* Source/JavaScriptCore/runtime/RegExpPrototype.cpp:
(JSC::regExpFlagsWatchpointIsValid):
(JSC::JSC_DEFINE_HOST_FUNCTION):
Canonical link: https://commits.webkit.org/316106@main
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