bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Improve tt-heavy expansion performance.

Browse source
This commit is contained in:
Jeffrey Seyfried 2016-11-03 11:59:43 +00:00
parent 7ae083383d
commit 23ad6fdb66
3 changed files with 23 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

9
src/libsyntax/parse/parser.rs
View file

@ -212,6 +212,7 @@ pub struct Parser<'a> {
pub expected_tokens: Vec<TokenType>,
pub tts: Vec<(TokenTree, usize)>,
pub desugar_doc_comments: bool,
pub allow_interpolated_tts: bool,
}
#[derive(PartialEq, Eq, Clone)]
@ -301,6 +302,7 @@ impl<'a> Parser<'a> {
expected_tokens: Vec::new(),
tts: Vec::new(),
desugar_doc_comments: desugar_doc_comments,
allow_interpolated_tts: true,
};
let tok = parser.next_tok();
@ -2718,7 +2720,12 @@ impl<'a> Parser<'a> {
if self.tts.last().map(|&(_, i)| i == 1).unwrap_or(false) {
let tt = self.tts.pop().unwrap().0;
self.bump();
return Ok(tt);
return Ok(if self.allow_interpolated_tts {
// avoid needlessly reparsing token trees in recursive macro expansions
TokenTree::Token(tt.span(), token::Interpolated(Rc::new(token::NtTT(tt))))
} else {
tt
});
}
let parsing_token_tree = ::std::mem::replace(&mut self.parsing_token_tree, true);