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LibJS/Bytecode: Don't reparse regular expressions on instantiation

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The RegExpLiteral AST node already has the parsed regex::Parser::Result
so let's plumb that over to the bytecode executable instead of reparsing
the regex every time NewRegExp is executed.

~12% speed-up on language/literals/regexp/S7.8.5_A2.1_T2.js in test262.
This commit is contained in:
Andreas Kling 2023-07-13 10:49:07 +02:00
parent a098f38cab
commit c0f985ffcf
9 changed files with 109 additions and 4 deletions
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20
Userland/Libraries/LibJS/Bytecode/Op.cpp
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@ -328,14 +328,30 @@ ThrowCompletionOr<void> NewObject::execute_impl(Bytecode::Interpreter& interpret
return {};
}
// 13.2.7.3 Runtime Semantics: Evaluation, https://tc39.es/ecma262/#sec-regular-expression-literals-runtime-semantics-evaluation
ThrowCompletionOr<void> NewRegExp::execute_impl(Bytecode::Interpreter& interpreter) const
{
auto& vm = interpreter.vm();
auto source = interpreter.current_executable().get_string(m_source_index);
auto& realm = *vm.current_realm();
// 1. Let pattern be CodePointsToString(BodyText of RegularExpressionLiteral).
auto pattern = interpreter.current_executable().get_string(m_source_index);
// 2. Let flags be CodePointsToString(FlagText of RegularExpressionLiteral).
auto flags = interpreter.current_executable().get_string(m_flags_index);
interpreter.accumulator() = TRY(regexp_create(vm, PrimitiveString::create(vm, source), PrimitiveString::create(vm, flags)));
// 3. Return ! RegExpCreate(pattern, flags).
auto& parsed_regex = interpreter.current_executable().regex_table->get(m_regex_index);
Regex<ECMA262> regex(parsed_regex.regex, parsed_regex.pattern, parsed_regex.flags);
// NOTE: We bypass RegExpCreate and subsequently RegExpAlloc as an optimization to use the already parsed values.
auto regexp_object = RegExpObject::create(realm, move(regex), move(pattern), move(flags));
// RegExpAlloc has these two steps from the 'Legacy RegExp features' proposal.
regexp_object->set_realm(*vm.current_realm());
// We don't need to check 'If SameValue(newTarget, thisRealm.[[Intrinsics]].[[%RegExp%]]) is true'
// here as we know RegExpCreate calls RegExpAlloc with %RegExp% for newTarget.
regexp_object->set_legacy_features_enabled(true);
interpreter.accumulator() = regexp_object;
return {};
}