Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 01f04c4fb45608321ce6be8237a0e90a2f487f86
https://github.com/WebKit/WebKit/commit/01f04c4fb45608321ce6be8237a0e90a2f487f86
Author: Sosuke Suzuki <[email protected]>
Date: 2026-08-20 (Thu, 20 Aug 2026)
Changed paths:
A JSTests/microbenchmarks/regexp-lookbehind-backreference.js
A JSTests/stress/regexp-lookbehind-jit-backreferences-unicode.js
A JSTests/stress/regexp-lookbehind-jit-backreferences.js
M Source/JavaScriptCore/yarr/YarrJIT.cpp
Log Message:
-----------
[YARR] Compile lookbehinds containing backreferences in the JIT
https://bugs.webkit.org/show_bug.cgi?id=321867
Reviewed by Daniel Liu.
A backreference inside a lookbehind sent the whole pattern to the interpreter.
Matched backward, a backreference succeeds when the captured text ends at the
current position.
The comparison loop runs down instead of up: the capture cursor starts at the
capture end, the
subject cursor at the current position, each step reads the unit before its
cursor and
decrements both, and the loop stops at the capture start. The availability
check becomes
index >= length. The case-insensitive comparisons, the duplicate named group
lookup, the
unicode reads (readCharacter() already decodes backward) and the quantifier
bookkeeping are
the forward code with the sign of the index moves flipped. Forward code
generation is
unchanged.
Baseline
Patched
regexp-lookbehind-backreference 571.5494+-5.9829 ^
52.8080+-0.6471 ^ definitely 10.8232x faster
Tests: JSTests/microbenchmarks/regexp-lookbehind-backreference.js
JSTests/stress/regexp-lookbehind-jit-backreferences-unicode.js
JSTests/stress/regexp-lookbehind-jit-backreferences.js
* JSTests/microbenchmarks/regexp-lookbehind-backreference.js: Added.
* JSTests/stress/regexp-lookbehind-jit-backreferences-unicode.js: Added.
(shouldBe):
(matchOf):
(indicesOf):
(matchAllOf):
* JSTests/stress/regexp-lookbehind-jit-backreferences.js: Added.
(shouldBe):
(matchOf):
(indicesOf):
(matchAllOf):
* Source/JavaScriptCore/yarr/YarrJIT.cpp:
Canonical link: https://commits.webkit.org/319561@main
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