Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 71471a58fedd5b39f591f59fd35b13e35827e915
https://github.com/WebKit/WebKit/commit/71471a58fedd5b39f591f59fd35b13e35827e915
Author: Tyler Wilcock <[email protected]>
Date: 2026-04-13 (Mon, 13 Apr 2026)
Changed paths:
M Source/WebCore/accessibility/AccessibilityRenderObject.cpp
M Source/WebCore/accessibility/AccessibilitySVGObject.cpp
M Source/WebCore/accessibility/AccessibilitySVGObject.h
Log Message:
-----------
AX: SVG accname computation expensive in Speedometer runs with accessibility
enabled
https://bugs.webkit.org/show_bug.cgi?id=312163
rdar://174665355
Reviewed by Joshua Hoffman.
Profiling a Speedometer benchmark run shows
AccessibilitySVGObject::accessibilityText() as a significant hotspot during
isolated tree creation (~2,500 samples / ~7.5% of all AX work on the main
thread). The cost comes from
childElementWithMatchingLanguage(), which calls
indexOfBestMatchingLanguageInList(), an expensive Cocoa NSLocale/ICU
locale matching operation.
This PR greatly optimizes accessibilityText() by reducing repeated and
unnecessary work:
4 → 0-2 indexOfBestMatchingLanguageInList calls per element in
accessibilityText() (the hot path during tree building)
4 → 1 languageIncludingAncestors() call
4 → 1 defaultLanguage() call
0 calls to any of the above when no child has a lang attribute. This is the
common case for Chart.js SVGs.
0 calls to any of the above when there are no <title>/<desc> children at all.
This yields a 1.25% improvement in our Speedometer runtime with accessibility
enabled.
* Source/WebCore/accessibility/AccessibilityRenderObject.cpp:
(WebCore::AccessibilityRenderObject::updateRoleAfterChildrenCreation):
* Source/WebCore/accessibility/AccessibilitySVGObject.cpp:
(WebCore::AccessibilitySVGObject::childElementWithMatchingLanguage const):
(WebCore::AccessibilitySVGObject::accessibilityText const):
(WebCore::AccessibilitySVGObject::matchingTitleAndDescChildren const):
(WebCore::AccessibilitySVGObject::descriptionFromTitleChild const):
(WebCore::AccessibilitySVGObject::helpTextFromChildren const):
* Source/WebCore/accessibility/AccessibilitySVGObject.h:
Canonical link: https://commits.webkit.org/311174@main
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