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perf(parser): cache redundant token operations in hot paths #13775

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merged 1 commit into from
Sep 15, 2025
Merged

perf(parser): cache redundant token operations in hot paths #13775

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25 changes: 15 additions & 10 deletions crates/oxc_parser/src/js/expression.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -165,7 +165,8 @@ impl<'a> ParserImpl<'a> {
return self.parse_function_expression(span, r#async);
}

match self.cur_kind() {
let kind = self.cur_kind();
match kind {
Kind::Ident => self.parse_identifier_expression(), // fast path, keywords are checked at the end
// ArrayLiteral
Kind::LBrack => self.parse_array_expression(),
Expand Down Expand Up @@ -255,7 +256,8 @@ impl<'a> ParserImpl<'a> {
/// [Literal Expression](https://tc39.es/ecma262/#prod-Literal)
/// parses string | true | false | null | number
pub(crate) fn parse_literal_expression(&mut self) -> Expression<'a> {
match self.cur_kind() {
let kind = self.cur_kind();
match kind {
Kind::Str => {
let lit = self.parse_literal_string();
Expression::StringLiteral(self.alloc(lit))
Expand Down Expand Up @@ -301,10 +303,11 @@ impl<'a> ParserImpl<'a> {
pub(crate) fn parse_literal_number(&mut self) -> NumericLiteral<'a> {
let token = self.cur_token();
let span = token.span();
let kind = token.kind();
let src = self.cur_src();
let value = match token.kind() {
let value = match kind {
Kind::Decimal | Kind::Binary | Kind::Octal | Kind::Hex => {
parse_int(src, token.kind(), token.has_separator())
parse_int(src, kind, token.has_separator())
}
Kind::Float | Kind::PositiveExponential | Kind::NegativeExponential => {
parse_float(src, token.has_separator())
Expand All @@ -315,7 +318,7 @@ impl<'a> ParserImpl<'a> {
self.set_fatal_error(diagnostics::invalid_number(err, span));
0.0 // Dummy value
});
let base = match token.kind() {
let base = match kind {
Kind::Decimal => NumberBase::Decimal,
Kind::Float => NumberBase::Float,
Kind::Binary => NumberBase::Binary,
Expand All @@ -335,18 +338,19 @@ impl<'a> ParserImpl<'a> {
}

pub(crate) fn parse_literal_bigint(&mut self) -> BigIntLiteral<'a> {
let base = match self.cur_kind() {
let token = self.cur_token();
let kind = token.kind();
let base = match kind {
Kind::Decimal => BigintBase::Decimal,
Kind::Binary => BigintBase::Binary,
Kind::Octal => BigintBase::Octal,
Kind::Hex => BigintBase::Hex,
_ => return self.unexpected(),
};
let token = self.cur_token();
let span = token.span();
let raw = self.cur_src();
let src = raw.strip_suffix('n').unwrap();
let value = parse_big_int(src, token.kind(), token.has_separator(), self.ast.allocator);
let value = parse_big_int(src, kind, token.has_separator(), self.ast.allocator);

self.bump_any();
self.ast.big_int_literal(span, value, Some(Atom::from(raw)), base)
Expand Down Expand Up @@ -1017,8 +1021,9 @@ impl<'a> ParserImpl<'a> {
let span = self.start_span();
let lhs = self.parse_lhs_expression_or_higher();
// ++ -- postfix update expressions
if self.cur_kind().is_update_operator() && !self.cur_token().is_on_new_line() {
let operator = map_update_operator(self.cur_kind());
let post_kind = self.cur_kind();
if post_kind.is_update_operator() && !self.cur_token().is_on_new_line() {
let operator = map_update_operator(post_kind);
self.bump_any();
let lhs = SimpleAssignmentTarget::cover(lhs, self);
return self.ast.expression_update(self.end_span(span), operator, false, lhs);
Expand Down
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