diff options
| -rw-r--r-- | src/librustc_expand/lib.rs | 1 | ||||
| -rw-r--r-- | src/librustc_expand/mbe/macro_parser.rs | 38 | ||||
| -rw-r--r-- | src/librustc_expand/mbe/macro_rules.rs | 62 |
3 files changed, 56 insertions, 45 deletions
diff --git a/src/librustc_expand/lib.rs b/src/librustc_expand/lib.rs index 4fe7c268c4f..f119c956ced 100644 --- a/src/librustc_expand/lib.rs +++ b/src/librustc_expand/lib.rs @@ -1,3 +1,4 @@ +#![feature(cow_is_borrowed)] #![feature(crate_visibility_modifier)] #![feature(decl_macro)] #![feature(proc_macro_diagnostic)] diff --git a/src/librustc_expand/mbe/macro_parser.rs b/src/librustc_expand/mbe/macro_parser.rs index b14725fd731..78f22f3e443 100644 --- a/src/librustc_expand/mbe/macro_parser.rs +++ b/src/librustc_expand/mbe/macro_parser.rs @@ -78,13 +78,11 @@ use crate::mbe::{self, TokenTree}; use rustc_ast_pretty::pprust; use rustc_parse::parser::{FollowedByType, Parser, PathStyle}; -use rustc_parse::Directory; use rustc_session::parse::ParseSess; use rustc_span::symbol::{kw, sym, Symbol}; use syntax::ast::{Ident, Name}; use syntax::ptr::P; use syntax::token::{self, DocComment, Nonterminal, Token}; -use syntax::tokenstream::TokenStream; use rustc_errors::{FatalError, PResult}; use rustc_span::Span; @@ -92,6 +90,7 @@ use smallvec::{smallvec, SmallVec}; use rustc_data_structures::fx::FxHashMap; use rustc_data_structures::sync::Lrc; +use std::borrow::Cow; use std::collections::hash_map::Entry::{Occupied, Vacant}; use std::mem; use std::ops::{Deref, DerefMut}; @@ -613,28 +612,9 @@ fn inner_parse_loop<'root, 'tt>( Success(()) } -/// Use the given sequence of token trees (`ms`) as a matcher. Match the given token stream `tts` -/// against it and return the match. -/// -/// # Parameters -/// -/// - `sess`: The session into which errors are emitted -/// - `tts`: The tokenstream we are matching against the pattern `ms` -/// - `ms`: A sequence of token trees representing a pattern against which we are matching -/// - `directory`: Information about the file locations (needed for the black-box parser) -/// - `recurse_into_modules`: Whether or not to recurse into modules (needed for the black-box -/// parser) -pub(super) fn parse( - sess: &ParseSess, - tts: TokenStream, - ms: &[TokenTree], - directory: Option<Directory<'_>>, - recurse_into_modules: bool, -) -> NamedParseResult { - // Create a parser that can be used for the "black box" parts. - let mut parser = - Parser::new(sess, tts, directory, recurse_into_modules, true, rustc_parse::MACRO_ARGUMENTS); - +/// Use the given sequence of token trees (`ms`) as a matcher. Match the token +/// stream from the given `parser` against it and return the match. +pub(super) fn parse_tt(parser: &mut Cow<'_, Parser<'_>>, ms: &[TokenTree]) -> NamedParseResult { // A queue of possible matcher positions. We initialize it with the matcher position in which // the "dot" is before the first token of the first token tree in `ms`. `inner_parse_loop` then // processes all of these possible matcher positions and produces possible next positions into @@ -659,7 +639,7 @@ pub(super) fn parse( // parsing from the black-box parser done. The result is that `next_items` will contain a // bunch of possible next matcher positions in `next_items`. match inner_parse_loop( - sess, + parser.sess, &mut cur_items, &mut next_items, &mut eof_items, @@ -684,7 +664,7 @@ pub(super) fn parse( if eof_items.len() == 1 { let matches = eof_items[0].matches.iter_mut().map(|dv| Lrc::make_mut(dv).pop().unwrap()); - return nameize(sess, ms, matches); + return nameize(parser.sess, ms, matches); } else if eof_items.len() > 1 { return Error( parser.token.span, @@ -736,13 +716,13 @@ pub(super) fn parse( // If there are no possible next positions AND we aren't waiting for the black-box parser, // then there is a syntax error. else if bb_items.is_empty() && next_items.is_empty() { - return Failure(parser.token.take(), "no rules expected this token in macro call"); + return Failure(parser.token.clone(), "no rules expected this token in macro call"); } // Dump all possible `next_items` into `cur_items` for the next iteration. else if !next_items.is_empty() { // Now process the next token cur_items.extend(next_items.drain(..)); - parser.bump(); + parser.to_mut().bump(); } // Finally, we have the case where we need to call the black-box parser to get some // nonterminal. @@ -754,7 +734,7 @@ pub(super) fn parse( let match_cur = item.match_cur; item.push_match( match_cur, - MatchedNonterminal(Lrc::new(parse_nt(&mut parser, span, ident.name))), + MatchedNonterminal(Lrc::new(parse_nt(parser.to_mut(), span, ident.name))), ); item.idx += 1; item.match_cur += 1; diff --git a/src/librustc_expand/mbe/macro_rules.rs b/src/librustc_expand/mbe/macro_rules.rs index 29d41543fbf..9432790e78c 100644 --- a/src/librustc_expand/mbe/macro_rules.rs +++ b/src/librustc_expand/mbe/macro_rules.rs @@ -1,11 +1,11 @@ -use crate::base::{DummyResult, ExtCtxt, MacResult, TTMacroExpander}; +use crate::base::{DummyResult, ExpansionData, ExtCtxt, MacResult, TTMacroExpander}; use crate::base::{SyntaxExtension, SyntaxExtensionKind}; use crate::expand::{ensure_complete_parse, parse_ast_fragment, AstFragment, AstFragmentKind}; use crate::mbe; use crate::mbe::macro_check; -use crate::mbe::macro_parser::parse; +use crate::mbe::macro_parser::parse_tt; use crate::mbe::macro_parser::{Error, Failure, Success}; -use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, NamedParseResult}; +use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq}; use crate::mbe::transcribe::transcribe; use rustc_ast_pretty::pprust; @@ -166,9 +166,9 @@ impl TTMacroExpander for MacroRulesMacroExpander { } } -fn trace_macros_note(cx: &mut ExtCtxt<'_>, sp: Span, message: String) { +fn trace_macros_note(cx_expansions: &mut FxHashMap<Span, Vec<String>>, sp: Span, message: String) { let sp = sp.macro_backtrace().last().map(|trace| trace.call_site).unwrap_or(sp); - cx.expansions.entry(sp).or_default().push(message); + cx_expansions.entry(sp).or_default().push(message); } /// Given `lhses` and `rhses`, this is the new macro we create @@ -184,12 +184,36 @@ fn generic_extension<'cx>( ) -> Box<dyn MacResult + 'cx> { if cx.trace_macros() { let msg = format!("expanding `{}! {{ {} }}`", name, pprust::tts_to_string(arg.clone())); - trace_macros_note(cx, sp, msg); + trace_macros_note(&mut cx.expansions, sp, msg); } // Which arm's failure should we report? (the one furthest along) let mut best_failure: Option<(Token, &str)> = None; + + // We create a base parser that can be used for the "black box" parts. + // Every iteration needs a fresh copy of that base parser. However, the + // parser is not mutated on many of the iterations, particularly when + // dealing with macros like this: + // + // macro_rules! foo { + // ("a") => (A); + // ("b") => (B); + // ("c") => (C); + // // ... etc. (maybe hundreds more) + // } + // + // as seen in the `html5ever` benchmark. We use a `Cow` so that the base + // parser is only cloned when necessary (upon mutation). Furthermore, we + // reinitialize the `Cow` with the base parser at the start of every + // iteration, so that any mutated parsers are not reused. This is all quite + // hacky, but speeds up the `html5ever` benchmark significantly. (Issue + // 68836 suggests a more comprehensive but more complex change to deal with + // this situation.) + let base_parser = base_parser_from_cx(&cx.current_expansion, &cx.parse_sess, arg.clone()); + for (i, lhs) in lhses.iter().enumerate() { + let mut parser = Cow::Borrowed(&base_parser); + // try each arm's matchers let lhs_tt = match *lhs { mbe::TokenTree::Delimited(_, ref delim) => &delim.tts[..], @@ -202,7 +226,7 @@ fn generic_extension<'cx>( // are not recorded. On the first `Success(..)`ful matcher, the spans are merged. let mut gated_spans_snaphot = mem::take(&mut *cx.parse_sess.gated_spans.spans.borrow_mut()); - match parse_tt(cx, lhs_tt, arg.clone()) { + match parse_tt(&mut parser, lhs_tt) { Success(named_matches) => { // The matcher was `Success(..)`ful. // Merge the gated spans from parsing the matcher with the pre-existing ones. @@ -232,7 +256,7 @@ fn generic_extension<'cx>( if cx.trace_macros() { let msg = format!("to `{}`", pprust::tts_to_string(tts.clone())); - trace_macros_note(cx, sp, msg); + trace_macros_note(&mut cx.expansions, sp, msg); } let directory = Directory { @@ -269,6 +293,7 @@ fn generic_extension<'cx>( // Restore to the state before snapshotting and maybe try again. mem::swap(&mut gated_spans_snaphot, &mut cx.parse_sess.gated_spans.spans.borrow_mut()); } + drop(base_parser); let (token, label) = best_failure.expect("ran no matchers"); let span = token.span.substitute_dummy(sp); @@ -286,7 +311,9 @@ fn generic_extension<'cx>( mbe::TokenTree::Delimited(_, ref delim) => &delim.tts[..], _ => continue, }; - match parse_tt(cx, lhs_tt, arg.clone()) { + let base_parser = + base_parser_from_cx(&cx.current_expansion, &cx.parse_sess, arg.clone()); + match parse_tt(&mut Cow::Borrowed(&base_parser), lhs_tt) { Success(_) => { if comma_span.is_dummy() { err.note("you might be missing a comma"); @@ -368,7 +395,8 @@ pub fn compile_declarative_macro( ), ]; - let argument_map = match parse(sess, body, &argument_gram, None, true) { + let base_parser = Parser::new(sess, body, None, true, true, rustc_parse::MACRO_ARGUMENTS); + let argument_map = match parse_tt(&mut Cow::Borrowed(&base_parser), &argument_gram) { Success(m) => m, Failure(token, msg) => { let s = parse_failure_msg(&token); @@ -1184,14 +1212,16 @@ fn quoted_tt_to_string(tt: &mbe::TokenTree) -> String { } } -/// Use this token tree as a matcher to parse given tts. -fn parse_tt(cx: &ExtCtxt<'_>, mtch: &[mbe::TokenTree], tts: TokenStream) -> NamedParseResult { - // `None` is because we're not interpolating +fn base_parser_from_cx<'cx>( + current_expansion: &'cx ExpansionData, + sess: &'cx ParseSess, + tts: TokenStream, +) -> Parser<'cx> { let directory = Directory { - path: Cow::from(cx.current_expansion.module.directory.as_path()), - ownership: cx.current_expansion.directory_ownership, + path: Cow::from(current_expansion.module.directory.as_path()), + ownership: current_expansion.directory_ownership, }; - parse(cx.parse_sess(), tts, mtch, Some(directory), true) + Parser::new(sess, tts, Some(directory), true, true, rustc_parse::MACRO_ARGUMENTS) } /// Generates an appropriate parsing failure message. For EOF, this is "unexpected end...". For |