Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 0206365a0d08367d32abb77c39420dac472924b4
https://github.com/WebKit/WebKit/commit/0206365a0d08367d32abb77c39420dac472924b4
Author: Yusuke Suzuki <[email protected]>
Date: 2026-05-27 (Wed, 27 May 2026)
Changed paths:
A JSTests/stress/map-set-for-of-fast-iterator-storage.js
M Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp
Log Message:
-----------
[JSC] Set storage of JSMapIterator / JSSetIterator creation in DFG / FTL
https://bugs.webkit.org/show_bug.cgi?id=315648
rdar://178032814
Reviewed by Yijia Huang.
Let's set storage of JSMapIterator / JSSetIterator for FastMap / FastSet
iteration in DFG / FTL. While nullptr works, setting this avoids calling
an operation at the first call of `next()`, and it is more aligned to
C++ code.
ToT Patched
for-of-map-entries-small 9.8359+-0.0752 ^ 9.5363+-0.0646
^ definitely 1.0314x faster
set-for-of 1.0529+-0.0154 ? 1.0660+-0.0151
? might be 1.0124x slower
for-of-set-values 2.5517+-0.0118 ? 2.5590+-0.0140
?
for-of-map-entries 8.8384+-0.0613 ^ 8.7312+-0.0372
^ definitely 1.0123x faster
map-for-of 1.8168+-0.0151 ? 1.8186+-0.0154
?
for-of-set-values-small 3.2684+-0.0242 ^ 3.0344+-0.0113
^ definitely 1.0771x faster
<geometric> 3.3387+-0.0128 ^ 3.2830+-0.0104
^ definitely 1.0170x faster
Test: JSTests/stress/map-set-for-of-fast-iterator-storage.js
* JSTests/stress/map-set-for-of-fast-iterator-storage.js: Added.
(shouldBe):
(forOfMap):
(testEmptyMap):
(testNonEmptyMap):
(testMapWithDeletions):
(testEmptySet):
(testNonEmptySet):
(testSetWithDeletions):
(testMapMutationDuringIteration):
(testSetMutationDuringIteration):
(testReusedEmptyMap):
(testReusedEmptySet):
* Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::handleIteratorOpen):
Canonical link: https://commits.webkit.org/313982@main
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