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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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39
Userland/Libraries/LibRegex/RegexParser.cpp
View file

@ -150,7 +150,6 @@ ALWAYS_INLINE void Parser::reset()
m_parser_state.capture_group_minimum_lengths.clear();
m_parser_state.capture_groups_count = 0;
m_parser_state.named_capture_groups_count = 0;
m_parser_state.named_capture_group_minimum_lengths.clear();
m_parser_state.named_capture_groups.clear();
}
@ -780,12 +779,8 @@ ALWAYS_INLINE bool PosixExtendedParser::parse_sub_expression(ByteCode& stack, si
}
}
if (!(m_parser_state.regex_options & AllFlags::SkipSubExprResults || prevent_capture_group)) {
if (capture_group_name.has_value())
bytecode.insert_bytecode_group_capture_left(capture_group_name.value());
else
bytecode.insert_bytecode_group_capture_left(m_parser_state.capture_groups_count);
}
if (!(m_parser_state.regex_options & AllFlags::SkipSubExprResults || prevent_capture_group))
bytecode.insert_bytecode_group_capture_left(m_parser_state.capture_groups_count);
ByteCode capture_group_bytecode;
@ -814,12 +809,12 @@ ALWAYS_INLINE bool PosixExtendedParser::parse_sub_expression(ByteCode& stack, si
if (!(m_parser_state.regex_options & AllFlags::SkipSubExprResults || prevent_capture_group)) {
if (capture_group_name.has_value()) {
bytecode.insert_bytecode_group_capture_right(capture_group_name.value());
bytecode.insert_bytecode_group_capture_right(m_parser_state.capture_groups_count, capture_group_name.value());
++m_parser_state.named_capture_groups_count;
} else {
bytecode.insert_bytecode_group_capture_right(m_parser_state.capture_groups_count);
++m_parser_state.capture_groups_count;
}
++m_parser_state.capture_groups_count;
}
should_parse_repetition_symbol = true;
break;
@ -1564,14 +1559,14 @@ bool ECMA262Parser::parse_atom_escape(ByteCode& stack, size_t& match_length_mini
set_error(Error::InvalidNameForCaptureGroup);
return false;
}
auto maybe_length = m_parser_state.named_capture_group_minimum_lengths.get(name);
if (!maybe_length.has_value()) {
auto maybe_capture_group = m_parser_state.named_capture_groups.get(name);
if (!maybe_capture_group.has_value()) {
set_error(Error::InvalidNameForCaptureGroup);
return false;
}
match_length_minimum += maybe_length.value();
match_length_minimum += maybe_capture_group->minimum_length;
stack.insert_bytecode_compare_named_reference(name);
stack.insert_bytecode_compare_values({ { CharacterCompareType::Reference, (ByteCodeValueType)maybe_capture_group->group_index } });
return true;
}
@ -2121,15 +2116,8 @@ bool ECMA262Parser::parse_capture_group(ByteCode& stack, size_t& match_length_mi
m_capture_groups_in_scope.last().empend(identifier);
};
auto clear_all_capture_groups_in_scope = [&] {
for (auto& entry : m_capture_groups_in_scope.last()) {
entry.visit(
[&](size_t index) {
stack.insert_bytecode_clear_capture_group(index);
},
[&](String const& name) {
stack.insert_bytecode_clear_named_capture_group(name);
});
}
for (auto& index : m_capture_groups_in_scope.last())
stack.insert_bytecode_clear_capture_group(index);
};
if (match(TokenType::Questionmark)) {
@ -2172,21 +2160,18 @@ bool ECMA262Parser::parse_capture_group(ByteCode& stack, size_t& match_length_mi
clear_all_capture_groups_in_scope();
exit_capture_group_scope();
register_capture_group_in_current_scope(name);
register_capture_group_in_current_scope(group_index);
consume(TokenType::RightParen, Error::MismatchingParen);
stack.insert_bytecode_group_capture_left(name);
stack.insert_bytecode_group_capture_left(group_index);
stack.extend(move(capture_group_bytecode));
stack.insert_bytecode_group_capture_right(name);
stack.insert_bytecode_group_capture_right(group_index);
stack.insert_bytecode_group_capture_right(group_index, name);
match_length_minimum += length;
m_parser_state.named_capture_group_minimum_lengths.set(name, length);
m_parser_state.capture_group_minimum_lengths.set(group_index, length);
m_parser_state.named_capture_groups.set(name, { group_index, length });
return true;
}