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LibRegex+LibJS: Combine named and unnamed capture groups in MatchState

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Combining these into one list helps reduce the size of MatchState, and
as a result, reduces the amount of memory consumed during execution of
very large regex matches.

Doing this also allows us to remove a few regex byte code instructions:
ClearNamedCaptureGroup, SaveLeftNamedCaptureGroup, and NamedReference.
Named groups now behave the same as unnamed groups for these operations.
Note that SaveRightNamedCaptureGroup still exists to cache the matched
group name.

This also removes the recursion level from the MatchState, as it can
exist as a local variable in Matcher::execute instead.
This commit is contained in:
Timothy Flynn 2021-08-14 16:28:54 -04:00 • committed by Linus Groh
parent fea181bde3
commit f1ce998d73
9 changed files with 69 additions and 202 deletions
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22
Userland/Libraries/LibRegex/RegexMatcher.cpp
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@ -149,10 +149,7 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const& views, Optiona
if (c_match_preallocation_count) {
state.matches.ensure_capacity(c_match_preallocation_count);
state.capture_group_matches.ensure_capacity(c_match_preallocation_count);
state.named_capture_group_matches.ensure_capacity(c_match_preallocation_count);
auto& capture_groups_count = m_pattern->parser_result.capture_groups_count;
auto& named_capture_groups_count = m_pattern->parser_result.named_capture_groups_count;
for (size_t j = 0; j < c_match_preallocation_count; ++j) {
state.matches.empend();
@ -160,9 +157,6 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const& views, Optiona
state.capture_group_matches.at(j).ensure_capacity(capture_groups_count);
for (size_t k = 0; k < capture_groups_count; ++k)
state.capture_group_matches.at(j).unchecked_append({});
state.named_capture_group_matches.unchecked_append({});
state.named_capture_group_matches.at(j).ensure_capacity(named_capture_groups_count);
}
}
@ -315,15 +309,9 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const& views, Optiona
matches.template remove_all_matching([](auto& match) { return match.view.is_null(); });
}
output_copy.named_capture_group_matches = state.named_capture_group_matches;
// Make sure there are as many capture matches as there are actual matches.
if (output_copy.named_capture_group_matches.size() < match_count)
output_copy.named_capture_group_matches.resize(match_count);
output_copy.matches = state.matches;
} else {
output_copy.capture_group_matches.clear_with_capacity();
output_copy.named_capture_group_matches.clear_with_capacity();
}
return {
@ -331,7 +319,6 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const& views, Optiona
match_count,
move(output_copy.matches),
move(output_copy.capture_group_matches),
move(output_copy.named_capture_group_matches),
output.operations,
m_pattern->parser_result.capture_groups_count,
m_pattern->parser_result.named_capture_groups_count,
@ -399,9 +386,8 @@ private:
template<class Parser>
Optional<bool> Matcher<Parser>::execute(MatchInput const& input, MatchState& state, MatchOutput& output) const
{
state.recursion_level = 0;
BumpAllocatedLinkedList<MatchState> states_to_try_next;
size_t recursion_level = 0;
auto& bytecode = m_pattern->parser_result.bytecode;
@ -410,7 +396,7 @@ Optional<bool> Matcher<Parser>::execute(MatchInput const& input, MatchState& sta
auto& opcode = bytecode.get_opcode(state);
#if REGEX_DEBUG
s_regex_dbg.print_opcode("VM", opcode, state, state.recursion_level, false);
s_regex_dbg.print_opcode("VM", opcode, state, recursion_level, false);
#endif
ExecutionResult result;
@ -435,7 +421,7 @@ Optional<bool> Matcher<Parser>::execute(MatchInput const& input, MatchState& sta
case ExecutionResult::Fork_PrioHigh:
states_to_try_next.append(state);
state.instruction_position = state.fork_at_position;
++state.recursion_level;
++recursion_level;
continue;
case ExecutionResult::Continue:
continue;
@ -454,7 +440,7 @@ Optional<bool> Matcher<Parser>::execute(MatchInput const& input, MatchState& sta
return false;
}
state = states_to_try_next.take_last();
++state.recursion_level;
++recursion_level;
continue;
}
}