Auto merge of #37318 - nnethercote:html5ever-more, r=nrc,eddyb
Avoid some allocations in the macro parser These three commits reduce the number of heap allocations done when compiling rustc-benchmarks/html5ever-2016-08-25 by 20%, from 16.5M to 13.3M. This speeds up (debug) compilation of it with a stage1 compiler by about 7%.
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commit
a117bba125
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@ -251,14 +251,22 @@ pub fn nameize(p_s: &ParseSess, ms: &[TokenTree], res: &[Rc<NamedMatch>])
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pub enum ParseResult<T> {
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Success(T),
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/// Arm failed to match
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Failure(syntax_pos::Span, String),
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/// Arm failed to match. If the second parameter is `token::Eof`, it
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/// indicates an unexpected end of macro invocation. Otherwise, it
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/// indicates that no rules expected the given token.
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Failure(syntax_pos::Span, Token),
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/// Fatal error (malformed macro?). Abort compilation.
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Error(syntax_pos::Span, String)
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}
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pub fn parse_failure_msg(tok: Token) -> String {
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match tok {
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token::Eof => "unexpected end of macro invocation".to_string(),
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_ => format!("no rules expected the token `{}`", pprust::token_to_string(&tok)),
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}
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}
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pub type NamedParseResult = ParseResult<HashMap<Ident, Rc<NamedMatch>>>;
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pub type PositionalParseResult = ParseResult<Vec<Rc<NamedMatch>>>;
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/// Perform a token equality check, ignoring syntax context (that is, an
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/// unhygienic comparison)
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@ -425,8 +433,8 @@ pub fn parse(sess: &ParseSess,
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cur_eis.push(ei);
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}
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TokenTree::Token(_, ref t) => {
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let mut ei_t = ei.clone();
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if token_name_eq(t,&tok) {
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let mut ei_t = ei.clone();
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ei_t.idx += 1;
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next_eis.push(ei_t);
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}
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@ -446,7 +454,7 @@ pub fn parse(sess: &ParseSess,
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} else if eof_eis.len() > 1 {
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return Error(sp, "ambiguity: multiple successful parses".to_string());
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} else {
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return Failure(sp, "unexpected end of macro invocation".to_string());
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return Failure(sp, token::Eof);
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}
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} else {
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if (!bb_eis.is_empty() && !next_eis.is_empty())
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@ -467,8 +475,7 @@ pub fn parse(sess: &ParseSess,
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}
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))
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} else if bb_eis.is_empty() && next_eis.is_empty() {
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return Failure(sp, format!("no rules expected the token `{}`",
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pprust::token_to_string(&tok)));
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return Failure(sp, tok);
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} else if !next_eis.is_empty() {
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/* Now process the next token */
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while !next_eis.is_empty() {
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@ -16,7 +16,7 @@ use ext::expand::{Expansion, ExpansionKind};
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use ext::placeholders;
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use ext::tt::macro_parser::{Success, Error, Failure};
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use ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
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use ext::tt::macro_parser::parse;
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use ext::tt::macro_parser::{parse, parse_failure_msg};
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use parse::ParseSess;
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use parse::lexer::new_tt_reader;
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use parse::parser::{Parser, Restrictions};
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@ -97,7 +97,7 @@ fn generic_extension<'cx>(cx: &'cx ExtCtxt,
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// Which arm's failure should we report? (the one furthest along)
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let mut best_fail_spot = DUMMY_SP;
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let mut best_fail_msg = "internal error: ran no matchers".to_string();
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let mut best_fail_tok = None;
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for (i, lhs) in lhses.iter().enumerate() { // try each arm's matchers
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let lhs_tt = match *lhs {
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@ -134,9 +134,9 @@ fn generic_extension<'cx>(cx: &'cx ExtCtxt,
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macro_ident: name
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})
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}
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Failure(sp, ref msg) => if sp.lo >= best_fail_spot.lo {
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Failure(sp, tok) => if sp.lo >= best_fail_spot.lo {
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best_fail_spot = sp;
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best_fail_msg = (*msg).clone();
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best_fail_tok = Some(tok);
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},
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Error(err_sp, ref msg) => {
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cx.span_fatal(err_sp.substitute_dummy(sp), &msg[..])
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@ -144,7 +144,8 @@ fn generic_extension<'cx>(cx: &'cx ExtCtxt,
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}
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}
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cx.span_fatal(best_fail_spot.substitute_dummy(sp), &best_fail_msg[..]);
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let best_fail_msg = parse_failure_msg(best_fail_tok.expect("ran no matchers"));
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cx.span_fatal(best_fail_spot.substitute_dummy(sp), &best_fail_msg);
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}
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pub struct MacroRulesExpander;
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@ -222,8 +223,12 @@ pub fn compile(sess: &ParseSess, def: &ast::MacroDef) -> SyntaxExtension {
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let argument_map = match parse(sess, &Vec::new(), arg_reader, &argument_gram) {
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Success(m) => m,
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Failure(sp, str) | Error(sp, str) => {
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panic!(sess.span_diagnostic.span_fatal(sp.substitute_dummy(def.span), &str));
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Failure(sp, tok) => {
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let s = parse_failure_msg(tok);
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panic!(sess.span_diagnostic.span_fatal(sp.substitute_dummy(def.span), &s));
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}
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Error(sp, s) => {
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panic!(sess.span_diagnostic.span_fatal(sp.substitute_dummy(def.span), &s));
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}
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};
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@ -25,6 +25,7 @@ use syntax::ext::base::{ExtCtxt, MacResult, DummyResult, MacEager};
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use syntax::ext::build::AstBuilder;
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use syntax::ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
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use syntax::ext::tt::macro_parser::{Success, Failure, Error};
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use syntax::ext::tt::macro_parser::parse_failure_msg;
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use syntax::ptr::P;
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use syntax_pos::Span;
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use rustc_plugin::Registry;
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@ -58,8 +59,11 @@ fn expand_mbe_matches(cx: &mut ExtCtxt, sp: Span, args: &[TokenTree])
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_ => unreachable!()
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}
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}
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Failure(_, s) | Error(_, s) => {
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panic!("expected Success, but got Error/Failure: {}", s);
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Failure(_, tok) => {
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panic!("expected Success, but got Failure: {}", parse_failure_msg(tok));
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}
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Error(_, s) => {
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panic!("expected Success, but got Error: {}", s);
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}
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};
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