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Auto merge of #34652 - jseyfried:fix_expansion_perf, r=nrc

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Fix expansion performance regression

**syntax-[breaking-change] cc #31645**

This fixes #34630 by reverting commit 5bf7970 of PR #33943, which landed in #34424.

By removing the `Rc<_>` wrapping around `Delimited` and `SequenceRepetition` in `TokenTree`, 5bf7970 made cloning `TokenTree`s more expensive. While this had no measurable performance impact on the compiler's crates, it caused an order of magnitude performance regression on some macro-heavy code in the wild. I believe this is due to clones of `TokenTree`s in `macro_parser.rs` and/or `macro_rules.rs`.

r? @nrc
This commit is contained in:
bors
2016-07-06 20:04:11 -07:00
committed by GitHub
parent 5c674a1147 547a930835
commit de78655bca
8 changed files with 72 additions and 53 deletions
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8
src/libsyntax/ext/expand.rs
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@@ -237,7 +237,7 @@ fn expand_mac_invoc<T>(mac: ast::Mac, ident: Option<Ident>, attrs: Vec<ast::Attr
},
});
let marked_tts = mark_tts(tts, mark);
let marked_tts = mark_tts(&tts, mark);
Some(expandfun.expand(fld.cx, call_site, &marked_tts))
}
@@ -257,7 +257,7 @@ fn expand_mac_invoc<T>(mac: ast::Mac, ident: Option<Ident>, attrs: Vec<ast::Attr
}
});
let marked_tts = mark_tts(tts, mark);
let marked_tts = mark_tts(&tts, mark);
Some(expander.expand(fld.cx, call_site, ident, marked_tts))
}
@@ -1130,7 +1130,7 @@ impl Folder for Marker {
Spanned {
node: Mac_ {
path: self.fold_path(node.path),
tts: self.fold_tts(node.tts),
tts: self.fold_tts(&node.tts),
},
span: self.new_span(span),
}
@@ -1145,7 +1145,7 @@ impl Folder for Marker {
}
// apply a given mark to the given token trees. Used prior to expansion of a macro.
fn mark_tts(tts: Vec<TokenTree>, m: Mrk) -> Vec<TokenTree> {
fn mark_tts(tts: &[TokenTree], m: Mrk) -> Vec<TokenTree> {
noop_fold_tts(tts, &mut Marker{mark:m, expn_id: None})
}