Yarr: JIT lookbehinds, first-code-point alternation dispatch, Boyer-Moore and /u·/v spec alignment, RegExp correctness fixes - #299

Merged

Jarred-Sumner merged 61 commits into

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claude/yarr-regex-perf-5197

Aug 11, 2026

Commits on Aug 2, 2026

Yarr JIT: compile lookbehind assertions

dylan-conway
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5f01951
Yarr: factor alternation prefixes and fold large alternations into a group

dylan-conway
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2e3e7ae
Yarr JIT: dispatch a group's alternatives on the first character

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cb14bcb
Yarr: also factor alternation prefixes inside pre-existing groups

dylan-conway
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106bc06
Yarr: harden alternation factoring against specialized group shapes

dylan-conway
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2f31936
Yarr JIT: compare dispatched literal alternatives inline

dylan-conway
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9e4a9d9
Yarr: fix review findings in the lookbehind/alternation series

dylan-conway
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5c57f84
Yarr: keep BOL-group lookbehind patterns on the interpreter instead of narrowing BOL bubbling

dylan-conway
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da67beb
Yarr: JIT-compile unicode lookbehinds through the mirrored-body machinery

dylan-conway
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26d6c4b
Yarr: address review nits in the lookbehind/alternation series

dylan-conway
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ad027ca
Yarr: score every Boyer-Moore sub-range, and allow the search on 8-bit unicode subjects

dylan-conway
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e1eecff
Yarr: pick the Boyer-Moore search loop by how often its candidates appear

dylan-conway
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2c97f93
Yarr: cover the Boyer-Moore search's any-character positions

dylan-conway
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bbc6100
Yarr: restore option gates for lookbehind JIT, alternation factoring, and first-character dispatch
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f83e5af
Yarr: bound alternation prefix factoring to linear memory and a fixed work budget
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8dcb75e
Yarr: never filter BOL-anchored alternatives beneath an inverted assertion
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159a531
Yarr JIT: only the term at input position 0 may record the match-start astral read
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67c65ff
Yarr JIT: cache each nested alternative chain's End op instead of re-walking it
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c7c4823
Yarr JIT: check isSafeToRecurse in assignAlternativeOffsets
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524ddfc
JSTests: add regression coverage for the lookbehind/alternation review findings
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d92e207
Yarr JIT: keep small frame-free alternations DFG-inlineable and skip dispatch for tiny groups
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37a8947
Yarr JIT: guard the backward unicode read paths with ENABLE(YARR_JIT_UNICODE_EXPRESSIONS)
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7202c83
Yarr JIT: a fused literal run may only record the match-start astral read for its first chunk
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3d23c0a
Yarr JIT: a fused literal run that stops before the alternative's last term must not take the string-list success exit
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5e22a71
Yarr: derive a character class's BMP/non-BMP widths from its final tables
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6fff5f8
Yarr JIT: stop a unicode backreference walk that steps past the capture's end
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159170f
Yarr interpreter: read astral code points correctly in unicode lookbehinds
Jarred-Sumner
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9d164e0
Yarr interpreter: skip every once-through alternative when advancing the start position
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bff1dcb
RegExp: never start or restart a /u match in the middle of a surrogate pair
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8531a54
Yarr: a quantified forward reference in a lookbehind must convert both split pieces to backreferences
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fda7bee
Yarr: a named backreference inside a lookbehind to a group captured before the lookbehind is an ordinary backreference
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ff857b6
Yarr: apply the pending /v set operation to an inverted property escape operand
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04f493f
RegExp: outline the /u start fixup so the match fast path stays small
dylan-conway
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976dfb7
Yarr JIT: dispatch the body alternation on its first character, framelessly
dylan-conway
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96935ab
Yarr JIT: put the frameless body dispatch behind useRegExpAlternationDispatch too
Jarred-Sumner
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110334b

Commits on Aug 3, 2026

Commits on Aug 4, 2026

Yarr: score a Boyer-Moore search range by its stride, not by a probability ceiling
dylan-conway
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127a0a3

Commits on Aug 9, 2026

Merge remote-tracking branch 'origin/main' into claude/yarr-regex-perf-5197
Jarred-Sumner
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6f3c96d

Commits on Aug 10, 2026

Commits on Aug 11, 2026