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perf(parser): reorder parse_statement match conditions (#7645)

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For performance reasons, match orders are:
1. plain if check
2. check current token
3. peek token
This commit is contained in:
Boshen 2024-12-04 12:31:48 +00:00
parent e923e4ee46
commit d503a84d57
2 changed files with 15 additions and 7 deletions
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4
crates/oxc_parser/src/js/expression.rs
View file

@ -170,8 +170,6 @@ impl<'a> ParserImpl<'a> {
match self.cur_kind() {
Kind::Ident => self.parse_identifier_expression(), // fast path, keywords are checked at the end
// Literal, RegularExpressionLiteral
kind if kind.is_literal() => self.parse_literal_expression(),
// ArrayLiteral
Kind::LBrack => self.parse_array_expression(),
// ObjectLiteral
@ -199,6 +197,8 @@ impl<'a> ParserImpl<'a> {
Kind::Slash | Kind::SlashEq => self
.parse_literal_regexp()
.map(|literal| Expression::RegExpLiteral(self.alloc(literal))),
// Literal, RegularExpressionLiteral
kind if kind.is_literal() => self.parse_literal_expression(),
// JSXElement, JSXFragment
Kind::LAngle if self.source_type.is_jsx() => self.parse_jsx_expression(),
_ => self.parse_identifier_expression(),

18
crates/oxc_parser/src/js/statement.rs
View file

@ -87,6 +87,10 @@ impl<'a> ParserImpl<'a> {
self.eat_decorators()?;
}
// For performance reasons, match orders are:
// 1. plain if check
// 2. check current token
// 3. peek token
match self.cur_kind() {
Kind::LCurly => self.parse_block_statement(),
Kind::Semicolon => Ok(self.parse_empty_statement()),
@ -101,24 +105,28 @@ impl<'a> ParserImpl<'a> {
Kind::Try => self.parse_try_statement(),
Kind::Debugger => self.parse_debugger_statement(),
Kind::Class => self.parse_class_statement(stmt_ctx, start_span),
Kind::Import if !matches!(self.peek_kind(), Kind::Dot | Kind::LParen) => {
self.parse_import_declaration()
}
Kind::Export => self.parse_export_declaration(),
// [+Return] ReturnStatement[?Yield, ?Await]
Kind::Return => self.parse_return_statement(),
Kind::Var => self.parse_variable_statement(stmt_ctx),
// Fast path
Kind::Function => self.parse_function_declaration(stmt_ctx),
Kind::Let if !self.cur_token().escaped() => self.parse_let(stmt_ctx),
Kind::Import if !matches!(self.peek_kind(), Kind::Dot | Kind::LParen) => {
self.parse_import_declaration()
}
Kind::Const if !(self.is_ts && self.is_at_enum_declaration()) => {
self.parse_variable_statement(stmt_ctx)
}
Kind::Let if !self.cur_token().escaped() => self.parse_let(stmt_ctx),
Kind::Await
if self.peek_kind() == Kind::Using && self.nth_kind(2).is_binding_identifier() =>
{
self.parse_using()
}
Kind::Using if self.peek_kind().is_binding_identifier() => self.parse_using(),
_ if self.at_function_with_async() => self.parse_function_declaration(stmt_ctx),
Kind::Async if self.peek_at(Kind::Function) && !self.peek_token().is_on_new_line => {
self.parse_function_declaration(stmt_ctx)
}
_ if self.is_ts && self.at_start_of_ts_declaration() => {
self.parse_ts_declaration_statement(start_span)
}