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Speed up expansion #42533

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Jun 10, 2017
+35 −28
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Speed up expansion #42533

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40 changes: 23 additions & 17 deletions src/libsyntax/ext/tt/macro_parser.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -139,13 +139,20 @@ struct MatcherPos {
sep: Option<Token>,
idx: usize,
up: Option<Box<MatcherPos>>,
matches: Vec<Vec<Rc<NamedMatch>>>,
matches: Vec<Rc<Vec<NamedMatch>>>,
match_lo: usize,
match_cur: usize,
match_hi: usize,
sp_lo: BytePos,
}

impl MatcherPos {
fn push_match(&mut self, idx: usize, m: NamedMatch) {
let matches = Rc::make_mut(&mut self.matches[idx]);
matches.push(m);
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What a lovely hack 😻

}
}

pub type NamedParseResult = ParseResult<HashMap<Ident, Rc<NamedMatch>>>;

pub fn count_names(ms: &[TokenTree]) -> usize {
Expand Down Expand Up @@ -199,14 +206,15 @@ fn initial_matcher_pos(ms: Vec<TokenTree>, lo: BytePos) -> Box<MatcherPos> {
/// only on the nesting depth of `ast::TTSeq`s in the originating
/// token tree it was derived from.

#[derive(Debug, Clone)]
pub enum NamedMatch {
MatchedSeq(Vec<Rc<NamedMatch>>, syntax_pos::Span),
MatchedSeq(Rc<Vec<NamedMatch>>, syntax_pos::Span),
MatchedNonterminal(Rc<Nonterminal>)
}

fn nameize<I: Iterator<Item=Rc<NamedMatch>>>(sess: &ParseSess, ms: &[TokenTree], mut res: I)
fn nameize<I: Iterator<Item=NamedMatch>>(sess: &ParseSess, ms: &[TokenTree], mut res: I)
-> NamedParseResult {
fn n_rec<I: Iterator<Item=Rc<NamedMatch>>>(sess: &ParseSess, m: &TokenTree, mut res: &mut I,
fn n_rec<I: Iterator<Item=NamedMatch>>(sess: &ParseSess, m: &TokenTree, mut res: &mut I,
ret_val: &mut HashMap<Ident, Rc<NamedMatch>>)
-> Result<(), (syntax_pos::Span, String)> {
match *m {
Expand All @@ -228,7 +236,8 @@ fn nameize<I: Iterator<Item=Rc<NamedMatch>>>(sess: &ParseSess, ms: &[TokenTree],
TokenTree::MetaVarDecl(sp, bind_name, _) => {
match ret_val.entry(bind_name) {
Vacant(spot) => {
spot.insert(res.next().unwrap());
// FIXME(simulacrum): Don't construct Rc here
spot.insert(Rc::new(res.next().unwrap()));
}
Occupied(..) => {
return Err((sp, format!("duplicated bind name: {}", bind_name)))
Expand Down Expand Up @@ -280,8 +289,8 @@ fn token_name_eq(t1 : &Token, t2 : &Token) -> bool {
}
}

fn create_matches(len: usize) -> Vec<Vec<Rc<NamedMatch>>> {
(0..len).into_iter().map(|_| Vec::new()).collect()
fn create_matches(len: usize) -> Vec<Rc<Vec<NamedMatch>>> {
(0..len).into_iter().map(|_| Rc::new(Vec::new())).collect()
}

fn inner_parse_loop(sess: &ParseSess,
Expand Down Expand Up @@ -320,15 +329,10 @@ fn inner_parse_loop(sess: &ParseSess,
// update matches (the MBE "parse tree") by appending
// each tree as a subtree.

// I bet this is a perf problem: we're preemptively
// doing a lot of array work that will get thrown away
// most of the time.

// Only touch the binders we have actually bound
for idx in ei.match_lo..ei.match_hi {
let sub = ei.matches[idx].clone();
new_pos.matches[idx]
.push(Rc::new(MatchedSeq(sub, Span { lo: ei.sp_lo, ..span })));
new_pos.push_match(idx, MatchedSeq(sub, Span { lo: ei.sp_lo, ..span }));
}

new_pos.match_cur = ei.match_hi;
Expand Down Expand Up @@ -362,7 +366,7 @@ fn inner_parse_loop(sess: &ParseSess,
new_ei.match_cur += seq.num_captures;
new_ei.idx += 1;
for idx in ei.match_cur..ei.match_cur + seq.num_captures {
new_ei.matches[idx].push(Rc::new(MatchedSeq(vec![], sp)));
new_ei.push_match(idx, MatchedSeq(Rc::new(vec![]), sp));
}
cur_eis.push(new_ei);
}
Expand Down Expand Up @@ -446,7 +450,9 @@ pub fn parse(sess: &ParseSess,
/* error messages here could be improved with links to orig. rules */
if token_name_eq(&parser.token, &token::Eof) {
if eof_eis.len() == 1 {
let matches = eof_eis[0].matches.iter_mut().map(|mut dv| dv.pop().unwrap());
let matches = eof_eis[0].matches.iter_mut().map(|mut dv| {
Rc::make_mut(dv).pop().unwrap()
});
return nameize(sess, ms, matches);
} else if eof_eis.len() > 1 {
return Error(parser.span, "ambiguity: multiple successful parses".to_string());
Expand Down Expand Up @@ -479,8 +485,8 @@ pub fn parse(sess: &ParseSess,
let mut ei = bb_eis.pop().unwrap();
if let TokenTree::MetaVarDecl(span, _, ident) = ei.top_elts.get_tt(ei.idx) {
let match_cur = ei.match_cur;
ei.matches[match_cur].push(Rc::new(MatchedNonterminal(
Rc::new(parse_nt(&mut parser, span, &ident.name.as_str())))));
ei.push_match(match_cur,
MatchedNonterminal(Rc::new(parse_nt(&mut parser, span, &ident.name.as_str()))));
ei.idx += 1;
ei.match_cur += 1;
} else {
Expand Down
4 changes: 2 additions & 2 deletions src/libsyntax/ext/tt/macro_rules.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -219,7 +219,7 @@ pub fn compile(sess: &ParseSess, features: &RefCell<Features>, def: &ast::Item)
let lhses = match *argument_map[&lhs_nm] {
MatchedSeq(ref s, _) => {
s.iter().map(|m| {
if let MatchedNonterminal(ref nt) = **m {
if let MatchedNonterminal(ref nt) = *m {
if let NtTT(ref tt) = **nt {
let tt = quoted::parse(tt.clone().into(), true, sess).pop().unwrap();
valid &= check_lhs_nt_follows(sess, features, &tt);
Expand All @@ -235,7 +235,7 @@ pub fn compile(sess: &ParseSess, features: &RefCell<Features>, def: &ast::Item)
let rhses = match *argument_map[&rhs_nm] {
MatchedSeq(ref s, _) => {
s.iter().map(|m| {
if let MatchedNonterminal(ref nt) = **m {
if let MatchedNonterminal(ref nt) = *m {
if let NtTT(ref tt) = **nt {
return quoted::parse(tt.clone().into(), false, sess).pop().unwrap();
}
Expand Down
17 changes: 9 additions & 8 deletions src/libsyntax/ext/tt/transcribe.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -182,15 +182,16 @@ fn lookup_cur_matched(ident: Ident,
repeats: &[(usize, usize)])
-> Option<Rc<NamedMatch>> {
interpolations.get(&ident).map(|matched| {
repeats.iter().fold(matched.clone(), |ad, &(idx, _)| {
match *ad {
MatchedNonterminal(_) => {
// end of the line; duplicate henceforth
ad.clone()
}
MatchedSeq(ref ads, _) => ads[idx].clone()
let mut matched = matched.clone();
for &(idx, _) in repeats {
let m = matched.clone();
match *m {
MatchedNonterminal(_) => break,
MatchedSeq(ref ads, _) => matched = Rc::new(ads[idx].clone()),
}
})
}

matched
})
}

Expand Down
2 changes: 1 addition & 1 deletion src/test/run-pass-fulldeps/auxiliary/procedural_mbe_matching.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,7 @@ fn expand_mbe_matches(cx: &mut ExtCtxt, _: Span, args: &[TokenTree])
let mac_expr = match (&*matched_nt, &*map[&Ident::from_str("pat")]) {
(&NtExpr(ref matched_expr), &MatchedSeq(ref pats, seq_sp)) => {
let pats: Vec<P<Pat>> = pats.iter().map(|pat_nt| {
match **pat_nt {
match *pat_nt {
MatchedNonterminal(ref nt) => match **nt {
NtPat(ref pat) => pat.clone(),
_ => unreachable!(),
Expand Down