Fixes handling of backreferences when the referenced capture group is
undefined or hasn't participated in the match.
CharacterCompareType::NamedReference is added to distinguish numbered
(\1) from named (\k<name>) backreferences. Numbered backreferences use
exact group lookup. Named backreferences search for participating
groups among duplicates.
Not accounting for opcode size when calculating incoming jump edges
meant that we were merging nodes where we otherwise shouldn't have been,
for example /.*a|.*b/.
The opcode may have last been accessed by
block_satisfies_atomic_rewrite_precondition, which would set it to a
state that no longer exists.
Set the state to the correct one unconditionally to ensure we're looking
at the right value.
Fixes#5145.
Fixes a bunch of websites breaking because we now verify jump offsets by
trying to remove 0-offset jumps.
This has been broken for a good while, it was just rare to see Repeat
inside alternatives that lended themselves well to tree alts.
Previously we were counting the total number of *nodes* in the tree for
the chain cost, which greatly underestimated its cost when large
bytecode entries were present,
This commit switches to estimating it using the total bytecode *size*,
which is a closer value to the true cost than the tree node count.
This corresponds to a ~4x perf improvement on /<script|<style|<link/ in
speedometer.
Repeat's 'offset' field is a bit odd in that it is treated as a negative
offset, causing a backwards jump when positive; the optimizer didn't
correctly model this behaviour, which caused crashes and misopts when
dealing with Repeats.
This commit fixes that behaviour.
fe46b2c141 added the reset-temp-inverse flag, but set it up so all
tempinverse ops were negated at the start of the next op; this commit
makes it so these flags actually persist for one op and not zero.
Fixes#2296.
