bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Avoid some tuple destructuring.

Browse source 
Surprisingly, this is a non-trivial performance win.
This commit is contained in:
Nicholas Nethercote 2022-04-20 16:34:33 +10:00
parent 880318c70a
commit 7a89255b20
1 changed files with 7 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

12
compiler/rustc_parse/src/parser/mod.rs
View file

@ -994,22 +994,24 @@ impl<'a> Parser<'a> {
/// Advance the parser by one token.
pub fn bump(&mut self) {
let (mut next, spacing) = self.token_cursor.inlined_next(self.desugar_doc_comments);
// Note: destructuring here would give nicer code, but it was found in #96210 to be slower
// than `.0`/`.1` access.
let mut next = self.token_cursor.inlined_next(self.desugar_doc_comments);
self.token_cursor.num_next_calls += 1;
// We've retrieved an token from the underlying
// cursor, so we no longer need to worry about
// an unglued token. See `break_and_eat` for more details
self.token_cursor.break_last_token = false;
if next.span.is_dummy() {
if next.0.span.is_dummy() {
// Tweak the location for better diagnostics, but keep syntactic context intact.
let fallback_span = self.token.span;
next.span = fallback_span.with_ctxt(next.span.ctxt());
next.0.span = fallback_span.with_ctxt(next.0.span.ctxt());
}
debug_assert!(!matches!(
next.kind,
next.0.kind,
token::OpenDelim(token::NoDelim) | token::CloseDelim(token::NoDelim)
));
self.inlined_bump_with((next, spacing))
self.inlined_bump_with(next)
}
/// Look-ahead `dist` tokens of `self.token` and get access to that token there.