diff --git a/compiler/rustc_expand/src/mbe/macro_parser.rs b/compiler/rustc_expand/src/mbe/macro_parser.rs index 76a92d1f8a0..ffe8b10e687 100644 --- a/compiler/rustc_expand/src/mbe/macro_parser.rs +++ b/compiler/rustc_expand/src/mbe/macro_parser.rs @@ -106,7 +106,7 @@ rustc_data_structures::static_assert_size!(NamedMatchVec, 48); /// /// This means a matcher can be represented by `&[MatcherLoc]`, and traversal mostly involves /// simply incrementing the current matcher position index by one. -enum MatcherLoc { +pub(super) enum MatcherLoc { Token { token: Token, }, @@ -138,6 +138,78 @@ enum MatcherLoc { Eof, } +pub(super) fn compute_locs(sess: &ParseSess, matcher: &[TokenTree]) -> Vec { + fn inner( + sess: &ParseSess, + tts: &[TokenTree], + locs: &mut Vec, + next_metavar: &mut usize, + seq_depth: usize, + ) { + for tt in tts { + match tt { + TokenTree::Token(token) => { + locs.push(MatcherLoc::Token { token: token.clone() }); + } + TokenTree::Delimited(_, delimited) => { + locs.push(MatcherLoc::Delimited); + inner(sess, &delimited.all_tts, locs, next_metavar, seq_depth); + } + TokenTree::Sequence(_, seq) => { + // We can't determine `idx_first_after` and construct the final + // `MatcherLoc::Sequence` until after `inner()` is called and the sequence end + // pieces are processed. So we push a dummy value (`Eof` is cheapest to + // construct) now, and overwrite it with the proper value below. + let dummy = MatcherLoc::Eof; + locs.push(dummy); + + let next_metavar_orig = *next_metavar; + let op = seq.kleene.op; + let idx_first = locs.len(); + let idx_seq = idx_first - 1; + inner(sess, &seq.tts, locs, next_metavar, seq_depth + 1); + + if let Some(separator) = &seq.separator { + locs.push(MatcherLoc::SequenceSep { separator: separator.clone() }); + locs.push(MatcherLoc::SequenceKleeneOpAfterSep { idx_first }); + } else { + locs.push(MatcherLoc::SequenceKleeneOpNoSep { op, idx_first }); + } + + // Overwrite the dummy value pushed above with the proper value. + locs[idx_seq] = MatcherLoc::Sequence { + op, + num_metavar_decls: seq.num_captures, + idx_first_after: locs.len(), + next_metavar: next_metavar_orig, + seq_depth, + }; + } + &TokenTree::MetaVarDecl(span, bind, kind) => { + locs.push(MatcherLoc::MetaVarDecl { + span, + bind, + kind, + next_metavar: *next_metavar, + seq_depth, + }); + *next_metavar += 1; + } + TokenTree::MetaVar(..) | TokenTree::MetaVarExpr(..) => unreachable!(), + } + } + } + + let mut locs = vec![]; + let mut next_metavar = 0; + inner(sess, matcher, &mut locs, &mut next_metavar, /* seq_depth */ 0); + + // A final entry is needed for eof. + locs.push(MatcherLoc::Eof); + + locs +} + /// A single matcher position, representing the state of matching. struct MatcherPos { /// The index into `TtParser::locs`, which represents the "dot". @@ -301,9 +373,6 @@ fn token_name_eq(t1: &Token, t2: &Token) -> bool { pub struct TtParser { macro_name: Ident, - /// The matcher of the current rule. - locs: Vec, - /// The set of current mps to be processed. This should be empty by the end of a successful /// execution of `parse_tt_inner`. cur_mps: Vec, @@ -324,7 +393,6 @@ impl TtParser { pub(super) fn new(macro_name: Ident) -> TtParser { TtParser { macro_name, - locs: vec![], cur_mps: vec![], next_mps: vec![], bb_mps: vec![], @@ -332,84 +400,6 @@ impl TtParser { } } - /// Convert a `&[TokenTree]` to a `&[MatcherLoc]`. Note: this conversion happens every time the - /// macro is called, which may be many times if there are many call sites or if it is - /// recursive. This conversion is fairly cheap and the representation is sufficiently better - /// for matching than `&[TokenTree]` that it's a clear performance win even with the overhead. - /// But it might be possible to move the conversion outwards so it only occurs once per macro. - fn compute_locs(&mut self, sess: &ParseSess, matcher: &[TokenTree]) -> usize { - fn inner( - sess: &ParseSess, - tts: &[TokenTree], - locs: &mut Vec, - next_metavar: &mut usize, - seq_depth: usize, - ) { - for tt in tts { - match tt { - TokenTree::Token(token) => { - locs.push(MatcherLoc::Token { token: token.clone() }); - } - TokenTree::Delimited(_, delimited) => { - locs.push(MatcherLoc::Delimited); - inner(sess, &delimited.all_tts, locs, next_metavar, seq_depth); - } - TokenTree::Sequence(_, seq) => { - // We can't determine `idx_first_after` and construct the final - // `MatcherLoc::Sequence` until after `inner()` is called and the sequence - // end pieces are processed. So we push a dummy value (`Eof` is cheapest to - // construct) now, and overwrite it with the proper value below. - let dummy = MatcherLoc::Eof; - locs.push(dummy); - - let next_metavar_orig = *next_metavar; - let op = seq.kleene.op; - let idx_first = locs.len(); - let idx_seq = idx_first - 1; - inner(sess, &seq.tts, locs, next_metavar, seq_depth + 1); - - if let Some(separator) = &seq.separator { - locs.push(MatcherLoc::SequenceSep { separator: separator.clone() }); - locs.push(MatcherLoc::SequenceKleeneOpAfterSep { idx_first }); - } else { - locs.push(MatcherLoc::SequenceKleeneOpNoSep { op, idx_first }); - } - - // Overwrite the dummy value pushed above with the proper value. - locs[idx_seq] = MatcherLoc::Sequence { - op, - num_metavar_decls: seq.num_captures, - idx_first_after: locs.len(), - next_metavar: next_metavar_orig, - seq_depth, - }; - } - &TokenTree::MetaVarDecl(span, bind, kind) => { - locs.push(MatcherLoc::MetaVarDecl { - span, - bind, - kind, - next_metavar: *next_metavar, - seq_depth, - }); - *next_metavar += 1; - } - TokenTree::MetaVar(..) | TokenTree::MetaVarExpr(..) => unreachable!(), - } - } - } - - self.locs.clear(); - let mut next_metavar = 0; - inner(sess, matcher, &mut self.locs, &mut next_metavar, /* seq_depth */ 0); - - // A final entry is needed for eof. - self.locs.push(MatcherLoc::Eof); - - // This is the number of metavar decls. - next_metavar - } - /// Process the matcher positions of `cur_mps` until it is empty. In the process, this will /// produce more mps in `next_mps` and `bb_mps`. /// @@ -420,7 +410,7 @@ impl TtParser { fn parse_tt_inner( &mut self, sess: &ParseSess, - num_metavar_decls: usize, + matcher: &[MatcherLoc], token: &Token, ) -> Option { // Matcher positions that would be valid if the macro invocation was over now. Only @@ -428,7 +418,7 @@ impl TtParser { let mut eof_mps = EofMatcherPositions::None; while let Some(mut mp) = self.cur_mps.pop() { - match &self.locs[mp.idx] { + match &matcher[mp.idx] { MatcherLoc::Token { token: t } => { // If it's a doc comment, we just ignore it and move on to the next tt in the // matcher. This is a bug, but #95267 showed that existing programs rely on @@ -536,7 +526,7 @@ impl TtParser { } MatcherLoc::Eof => { // We are past the matcher's end, and not in a sequence. Try to end things. - debug_assert_eq!(mp.idx, self.locs.len() - 1); + debug_assert_eq!(mp.idx, matcher.len() - 1); if *token == token::Eof { eof_mps = match eof_mps { EofMatcherPositions::None => EofMatcherPositions::One(mp), @@ -554,11 +544,10 @@ impl TtParser { if *token == token::Eof { Some(match eof_mps { EofMatcherPositions::One(mut eof_mp) => { - assert_eq!(eof_mp.matches.len(), num_metavar_decls); // Need to take ownership of the matches from within the `Lrc`. Lrc::make_mut(&mut eof_mp.matches); let matches = Lrc::try_unwrap(eof_mp.matches).unwrap().into_iter(); - self.nameize(sess, matches) + self.nameize(sess, matcher, matches) } EofMatcherPositions::Multiple => { Error(token.span, "ambiguity: multiple successful parses".to_string()) @@ -580,10 +569,8 @@ impl TtParser { pub(super) fn parse_tt( &mut self, parser: &mut Cow<'_, Parser<'_>>, - matcher: &[TokenTree], + matcher: &[MatcherLoc], ) -> NamedParseResult { - let num_metavar_decls = self.compute_locs(parser.sess, matcher); - // 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 `matcher`. // `parse_tt_inner` then processes all of these possible matcher positions and produces @@ -598,7 +585,7 @@ impl TtParser { // Process `cur_mps` until either we have finished the input or we need to get some // parsing from the black-box parser done. - if let Some(res) = self.parse_tt_inner(&parser.sess, num_metavar_decls, &parser.token) { + if let Some(res) = self.parse_tt_inner(&parser.sess, matcher, &parser.token) { return res; } @@ -626,7 +613,7 @@ impl TtParser { (0, 1) => { // We need to call the black-box parser to get some nonterminal. let mut mp = self.bb_mps.pop().unwrap(); - let loc = &self.locs[mp.idx]; + let loc = &matcher[mp.idx]; if let &MatcherLoc::MetaVarDecl { span, kind: Some(kind), @@ -664,7 +651,7 @@ impl TtParser { (_, _) => { // Too many possibilities! - return self.ambiguity_error(parser.token.span); + return self.ambiguity_error(matcher, parser.token.span); } } @@ -672,11 +659,15 @@ impl TtParser { } } - fn ambiguity_error(&self, token_span: rustc_span::Span) -> NamedParseResult { + fn ambiguity_error( + &self, + matcher: &[MatcherLoc], + token_span: rustc_span::Span, + ) -> NamedParseResult { let nts = self .bb_mps .iter() - .map(|mp| match &self.locs[mp.idx] { + .map(|mp| match &matcher[mp.idx] { MatcherLoc::MetaVarDecl { bind, kind: Some(kind), .. } => { format!("{} ('{}')", kind, bind) } @@ -702,12 +693,13 @@ impl TtParser { fn nameize>( &self, sess: &ParseSess, + matcher: &[MatcherLoc], mut res: I, ) -> NamedParseResult { // Make that each metavar has _exactly one_ binding. If so, insert the binding into the // `NamedParseResult`. Otherwise, it's an error. let mut ret_val = FxHashMap::default(); - for loc in self.locs.iter() { + for loc in matcher { if let &MatcherLoc::MetaVarDecl { span, bind, kind, .. } = loc { if kind.is_some() { match ret_val.entry(MacroRulesNormalizedIdent::new(bind)) { diff --git a/compiler/rustc_expand/src/mbe/macro_rules.rs b/compiler/rustc_expand/src/mbe/macro_rules.rs index 10b2b9f07e2..27fe78516a4 100644 --- a/compiler/rustc_expand/src/mbe/macro_rules.rs +++ b/compiler/rustc_expand/src/mbe/macro_rules.rs @@ -4,7 +4,7 @@ use crate::expand::{ensure_complete_parse, parse_ast_fragment, AstFragment, AstF use crate::mbe; use crate::mbe::macro_check; use crate::mbe::macro_parser::{Error, ErrorReported, Failure, Success, TtParser}; -use crate::mbe::macro_parser::{MatchedSeq, MatchedTokenTree}; +use crate::mbe::macro_parser::{MatchedSeq, MatchedTokenTree, MatcherLoc}; use crate::mbe::transcribe::transcribe; use rustc_ast as ast; @@ -159,7 +159,7 @@ struct MacroRulesMacroExpander { name: Ident, span: Span, transparency: Transparency, - lhses: Vec, + lhses: Vec>, rhses: Vec, valid: bool, is_local: bool, @@ -210,7 +210,7 @@ fn generic_extension<'cx, 'tt>( name: Ident, transparency: Transparency, arg: TokenStream, - lhses: &'tt [mbe::TokenTree], + lhses: &'tt [Vec], rhses: &'tt [mbe::TokenTree], is_local: bool, ) -> Box { @@ -245,14 +245,6 @@ fn generic_extension<'cx, 'tt>( // this situation.) let parser = parser_from_cx(sess, arg.clone()); - // A matcher is always delimited, but the delimiters are ignored. - let delimited_inner_tts = |tt: &'tt mbe::TokenTree| -> &'tt [mbe::TokenTree] { - match tt { - mbe::TokenTree::Delimited(_, delimited) => delimited.inner_tts(), - _ => cx.span_bug(sp, "malformed macro lhs"), - } - }; - // Try each arm's matchers. let mut tt_parser = TtParser::new(name); for (i, lhs) in lhses.iter().enumerate() { @@ -262,13 +254,19 @@ fn generic_extension<'cx, 'tt>( // are not recorded. On the first `Success(..)`ful matcher, the spans are merged. let mut gated_spans_snapshot = mem::take(&mut *sess.gated_spans.spans.borrow_mut()); - match tt_parser.parse_tt(&mut Cow::Borrowed(&parser), delimited_inner_tts(lhs)) { + match tt_parser.parse_tt(&mut Cow::Borrowed(&parser), lhs) { Success(named_matches) => { // The matcher was `Success(..)`ful. // Merge the gated spans from parsing the matcher with the pre-existing ones. sess.gated_spans.merge(gated_spans_snapshot); - let rhs = delimited_inner_tts(&rhses[i]).to_vec().clone(); + // Ignore the delimiters on the RHS. + let rhs = match &rhses[i] { + mbe::TokenTree::Delimited(_, delimited) => { + delimited.inner_tts().to_vec().clone() + } + _ => cx.span_bug(sp, "malformed macro rhs"), + }; let arm_span = rhses[i].span(); let rhs_spans = rhs.iter().map(|t| t.span()).collect::>(); @@ -346,10 +344,8 @@ fn generic_extension<'cx, 'tt>( // Check whether there's a missing comma in this macro call, like `println!("{}" a);` if let Some((arg, comma_span)) = arg.add_comma() { for lhs in lhses { - if let Success(_) = tt_parser.parse_tt( - &mut Cow::Borrowed(&parser_from_cx(sess, arg.clone())), - delimited_inner_tts(lhs), - ) { + let parser = parser_from_cx(sess, arg.clone()); + if let Success(_) = tt_parser.parse_tt(&mut Cow::Borrowed(&parser), lhs) { if comma_span.is_dummy() { err.note("you might be missing a comma"); } else { @@ -440,6 +436,8 @@ pub fn compile_declarative_macro( }), ), ]; + // Convert it into `MatcherLoc` form. + let argument_gram = mbe::macro_parser::compute_locs(&sess.parse_sess, &argument_gram); let parser = Parser::new(&sess.parse_sess, body, true, rustc_parse::MACRO_ARGUMENTS); let mut tt_parser = TtParser::new(def.ident); @@ -536,6 +534,25 @@ pub fn compile_declarative_macro( None => {} } + // Convert the lhses into `MatcherLoc` form, which is better for doing the + // actual matching. Unless the matcher is invalid. + let lhses = if valid { + lhses + .iter() + .map(|lhs| { + // Ignore the delimiters around the matcher. + match lhs { + mbe::TokenTree::Delimited(_, delimited) => { + mbe::macro_parser::compute_locs(&sess.parse_sess, delimited.inner_tts()) + } + _ => sess.parse_sess.span_diagnostic.span_bug(def.span, "malformed macro lhs"), + } + }) + .collect() + } else { + vec![] + }; + mk_syn_ext(Box::new(MacroRulesMacroExpander { name: def.ident, span: def.span,