Skip to content

[Instructions -0.16% vs main; paired PGO estimate] Avoid small macro matching and transcription allocations #136

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
xmakro wants to merge 1 commit into
base: main
Choose a base branch
from
Draft

[Instructions -0.16% vs main; paired PGO estimate] Avoid small macro matching and transcription allocations #136

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 5 additions & 2 deletions compiler/rustc_expand/src/mbe/macro_parser.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -722,14 +722,17 @@ impl TtParser {
ErrorReported(guarantee)
}

fn nameize<I: Iterator<Item = NamedMatch>>(
fn nameize<I: ExactSizeIterator<Item = NamedMatch>>(
&self,
matcher: &[MatcherLoc],
mut res: I,
) -> NamedMatches {
// Make that each metavar has _exactly one_ binding. If so, insert the binding into the
// `NamedParseResult`. Otherwise, it's an error.
let mut ret_val = FxHashMap::default();
if res.len() == 0 {
return FxHashMap::default();
}
let mut ret_val = FxHashMap::with_capacity_and_hasher(res.len(), Default::default());
for loc in matcher {
if let &MatcherLoc::MetaVarDecl { bind, .. } = loc
&& ret_val
Expand Down
5 changes: 3 additions & 2 deletions compiler/rustc_expand/src/mbe/transcribe.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -186,7 +186,7 @@ pub(super) fn transcribe<'a>(
src_span,
DelimSpacing::new(Spacing::Alone, Spacing::Alone)
)],
result: Vec::new(),
result: Vec::with_capacity(src.tts.len()),
result_stack: Vec::new(),
};

Expand Down Expand Up @@ -271,7 +271,8 @@ pub(super) fn transcribe<'a>(
tscx.marker.mark_span(&mut span.open);
tscx.marker.mark_span(&mut span.close);
tscx.stack.push(Frame::new_delimited(delimited, span, *spacing));
tscx.result_stack.push(mem::take(&mut tscx.result));
tscx.result_stack
.push(mem::replace(&mut tscx.result, Vec::with_capacity(delimited.tts.len())));
}

// Nothing much to do here. Just push the token to the result, being careful to
Expand Down