diff options
Diffstat (limited to 'compiler/rustc_parse/src/parser/mod.rs')
| -rw-r--r-- | compiler/rustc_parse/src/parser/mod.rs | 256 |
1 files changed, 115 insertions, 141 deletions
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs index cb6be8f412c..cd61584a876 100644 --- a/compiler/rustc_parse/src/parser/mod.rs +++ b/compiler/rustc_parse/src/parser/mod.rs @@ -19,7 +19,7 @@ pub use pat::{CommaRecoveryMode, RecoverColon, RecoverComma}; pub use path::PathStyle; use rustc_ast::ptr::P; -use rustc_ast::token::{self, DelimToken, Nonterminal, Token, TokenKind}; +use rustc_ast::token::{self, Delimiter, Nonterminal, Token, TokenKind}; use rustc_ast::tokenstream::AttributesData; use rustc_ast::tokenstream::{self, DelimSpan, Spacing}; use rustc_ast::tokenstream::{TokenStream, TokenTree}; @@ -123,8 +123,8 @@ pub struct Parser<'a> { pub capture_cfg: bool, restrictions: Restrictions, expected_tokens: Vec<TokenType>, - // Important: This must only be advanced from `next_tok` - // to ensure that `token_cursor.num_next_calls` is updated properly + // Important: This must only be advanced from `bump` to ensure that + // `token_cursor.num_next_calls` is updated properly. token_cursor: TokenCursor, desugar_doc_comments: bool, /// This field is used to keep track of how many left angle brackets we have seen. This is @@ -150,6 +150,11 @@ pub struct Parser<'a> { pub current_closure: Option<ClosureSpans>, } +// This type is used a lot, e.g. it's cloned when matching many declarative macro rules. Make sure +// it doesn't unintentionally get bigger. +#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))] +rustc_data_structures::static_assert_size!(Parser<'_>, 328); + /// Stores span information about a closure. #[derive(Clone)] pub struct ClosureSpans { @@ -203,12 +208,15 @@ impl<'a> Drop for Parser<'a> { #[derive(Clone)] struct TokenCursor { + // The current (innermost) frame. `frame` and `stack` could be combined, + // but it's faster to have them separately to access `frame` directly + // rather than via something like `stack.last().unwrap()` or + // `stack[stack.len() - 1]`. frame: TokenCursorFrame, + // Additional frames that enclose `frame`. stack: Vec<TokenCursorFrame>, desugar_doc_comments: bool, - // Counts the number of calls to `{,inlined_}next` or - // `{,inlined_}next_desugared`, depending on whether - // `desugar_doc_comments` is set. + // Counts the number of calls to `{,inlined_}next`. num_next_calls: usize, // During parsing, we may sometimes need to 'unglue' a // glued token into two component tokens @@ -236,75 +244,60 @@ struct TokenCursor { #[derive(Clone)] struct TokenCursorFrame { - delim: token::DelimToken, - span: DelimSpan, - open_delim: bool, + delim_sp: Option<(Delimiter, DelimSpan)>, tree_cursor: tokenstream::Cursor, - close_delim: bool, } impl TokenCursorFrame { - fn new(span: DelimSpan, delim: DelimToken, tts: TokenStream) -> Self { - TokenCursorFrame { - delim, - span, - open_delim: false, - tree_cursor: tts.into_trees(), - close_delim: false, - } + fn new(delim_sp: Option<(Delimiter, DelimSpan)>, tts: TokenStream) -> Self { + TokenCursorFrame { delim_sp, tree_cursor: tts.into_trees() } } } impl TokenCursor { - fn next(&mut self) -> (Token, Spacing) { - self.inlined_next() + fn next(&mut self, desugar_doc_comments: bool) -> (Token, Spacing) { + self.inlined_next(desugar_doc_comments) } /// This always-inlined version should only be used on hot code paths. #[inline(always)] - fn inlined_next(&mut self) -> (Token, Spacing) { + fn inlined_next(&mut self, desugar_doc_comments: bool) -> (Token, Spacing) { loop { - let (tree, spacing) = if !self.frame.open_delim { - self.frame.open_delim = true; - TokenTree::open_tt(self.frame.span, self.frame.delim).into() - } else if let Some(tree) = self.frame.tree_cursor.next_with_spacing() { - tree - } else if !self.frame.close_delim { - self.frame.close_delim = true; - TokenTree::close_tt(self.frame.span, self.frame.delim).into() + // FIXME: we currently don't return `Delimiter` open/close delims. To fix #67062 we will + // need to, whereupon the `delim != Delimiter::Invisible` conditions below can be + // removed. + if let Some((tree, spacing)) = self.frame.tree_cursor.next_with_spacing_ref() { + match tree { + &TokenTree::Token(ref token) => match (desugar_doc_comments, token) { + (true, &Token { kind: token::DocComment(_, attr_style, data), span }) => { + return self.desugar(attr_style, data, span); + } + _ => return (token.clone(), *spacing), + }, + &TokenTree::Delimited(sp, delim, ref tts) => { + // Set `open_delim` to true here because we deal with it immediately. + let frame = TokenCursorFrame::new(Some((delim, sp)), tts.clone()); + self.stack.push(mem::replace(&mut self.frame, frame)); + if delim != Delimiter::Invisible { + return (Token::new(token::OpenDelim(delim), sp.open), Spacing::Alone); + } + // No open delimeter to return; continue on to the next iteration. + } + }; } else if let Some(frame) = self.stack.pop() { + if let Some((delim, span)) = self.frame.delim_sp && delim != Delimiter::Invisible { + self.frame = frame; + return (Token::new(token::CloseDelim(delim), span.close), Spacing::Alone); + } self.frame = frame; - continue; + // No close delimiter to return; continue on to the next iteration. } else { - (TokenTree::Token(Token::new(token::Eof, DUMMY_SP)), Spacing::Alone) - }; - - match tree { - TokenTree::Token(token) => { - return (token, spacing); - } - TokenTree::Delimited(sp, delim, tts) => { - let frame = TokenCursorFrame::new(sp, delim, tts); - self.stack.push(mem::replace(&mut self.frame, frame)); - } + return (Token::new(token::Eof, DUMMY_SP), Spacing::Alone); } } } - fn next_desugared(&mut self) -> (Token, Spacing) { - self.inlined_next_desugared() - } - - /// This always-inlined version should only be used on hot code paths. - #[inline(always)] - fn inlined_next_desugared(&mut self) -> (Token, Spacing) { - let (data, attr_style, sp) = match self.inlined_next() { - (Token { kind: token::DocComment(_, attr_style, data), span }, _) => { - (data, attr_style, span) - } - tok => return tok, - }; - + fn desugar(&mut self, attr_style: AttrStyle, data: Symbol, span: Span) -> (Token, Spacing) { // Searches for the occurrences of `"#*` and returns the minimum number of `#`s // required to wrap the text. let mut num_of_hashes = 0; @@ -318,14 +311,14 @@ impl TokenCursor { num_of_hashes = cmp::max(num_of_hashes, count); } - let delim_span = DelimSpan::from_single(sp); + let delim_span = DelimSpan::from_single(span); let body = TokenTree::Delimited( delim_span, - token::Bracket, + Delimiter::Bracket, [ - TokenTree::token(token::Ident(sym::doc, false), sp), - TokenTree::token(token::Eq, sp), - TokenTree::token(TokenKind::lit(token::StrRaw(num_of_hashes), data, None), sp), + TokenTree::token(token::Ident(sym::doc, false), span), + TokenTree::token(token::Eq, span), + TokenTree::token(TokenKind::lit(token::StrRaw(num_of_hashes), data, None), span), ] .iter() .cloned() @@ -335,15 +328,14 @@ impl TokenCursor { self.stack.push(mem::replace( &mut self.frame, TokenCursorFrame::new( - delim_span, - token::NoDelim, + None, if attr_style == AttrStyle::Inner { - [TokenTree::token(token::Pound, sp), TokenTree::token(token::Not, sp), body] + [TokenTree::token(token::Pound, span), TokenTree::token(token::Not, span), body] .iter() .cloned() .collect::<TokenStream>() } else { - [TokenTree::token(token::Pound, sp), body] + [TokenTree::token(token::Pound, span), body] .iter() .cloned() .collect::<TokenStream>() @@ -351,7 +343,7 @@ impl TokenCursor { ), )); - self.next() + self.next(/* desugar_doc_comments */ false) } } @@ -436,10 +428,6 @@ impl<'a> Parser<'a> { desugar_doc_comments: bool, subparser_name: Option<&'static str>, ) -> Self { - let mut start_frame = TokenCursorFrame::new(DelimSpan::dummy(), token::NoDelim, tokens); - start_frame.open_delim = true; - start_frame.close_delim = true; - let mut parser = Parser { sess, token: Token::dummy(), @@ -449,7 +437,7 @@ impl<'a> Parser<'a> { restrictions: Restrictions::empty(), expected_tokens: Vec::new(), token_cursor: TokenCursor { - frame: start_frame, + frame: TokenCursorFrame::new(None, tokens), stack: Vec::new(), num_next_calls: 0, desugar_doc_comments, @@ -476,33 +464,6 @@ impl<'a> Parser<'a> { parser } - #[inline] - fn next_tok(&mut self, fallback_span: Span) -> (Token, Spacing) { - loop { - let (mut next, spacing) = if self.desugar_doc_comments { - self.token_cursor.inlined_next_desugared() - } else { - self.token_cursor.inlined_next() - }; - self.token_cursor.num_next_calls += 1; - // We've retrieved an token from the underlying - // cursor, so we no longer need to worry about - // an unglued token. See `break_and_eat` for more details - self.token_cursor.break_last_token = false; - if next.span.is_dummy() { - // Tweak the location for better diagnostics, but keep syntactic context intact. - next.span = fallback_span.with_ctxt(next.span.ctxt()); - } - if matches!( - next.kind, - token::OpenDelim(token::NoDelim) | token::CloseDelim(token::NoDelim) - ) { - continue; - } - return (next, spacing); - } - } - pub fn unexpected<T>(&mut self) -> PResult<'a, T> { match self.expect_one_of(&[], &[]) { Err(e) => Err(e), @@ -665,7 +626,7 @@ impl<'a> Parser<'a> { self.is_keyword_ahead(dist, &[kw::Const]) && self.look_ahead(dist + 1, |t| match t.kind { token::Interpolated(ref nt) => matches!(**nt, token::NtBlock(..)), - token::OpenDelim(DelimToken::Brace) => true, + token::OpenDelim(Delimiter::Brace) => true, _ => false, }) } @@ -697,7 +658,7 @@ impl<'a> Parser<'a> { // // If we consume any additional tokens, then this token // is not needed (we'll capture the entire 'glued' token), - // and `next_tok` will set this field to `None` + // and `bump` will set this field to `None` self.token_cursor.break_last_token = true; // Use the spacing of the glued token as the spacing // of the unglued second token. @@ -841,7 +802,7 @@ impl<'a> Parser<'a> { .span_suggestion_verbose( self.prev_token.span.shrink_to_hi().until(self.token.span), &msg, - " @ ".to_string(), + " @ ", Applicability::MaybeIncorrect, ) .emit(); @@ -857,7 +818,7 @@ impl<'a> Parser<'a> { .span_suggestion_short( sp, &format!("missing `{}`", token_str), - token_str.into(), + token_str, Applicability::MaybeIncorrect, ) .emit(); @@ -993,7 +954,7 @@ impl<'a> Parser<'a> { fn parse_delim_comma_seq<T>( &mut self, - delim: DelimToken, + delim: Delimiter, f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, ) -> PResult<'a, (Vec<T>, bool)> { self.parse_unspanned_seq( @@ -1008,7 +969,7 @@ impl<'a> Parser<'a> { &mut self, f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, ) -> PResult<'a, (Vec<T>, bool)> { - self.parse_delim_comma_seq(token::Paren, f) + self.parse_delim_comma_seq(Delimiter::Parenthesis, f) } /// Advance the parser by one token using provided token as the next one. @@ -1019,12 +980,6 @@ impl<'a> Parser<'a> { /// This always-inlined version should only be used on hot code paths. #[inline(always)] fn inlined_bump_with(&mut self, (next_token, next_spacing): (Token, Spacing)) { - // Bumping after EOF is a bad sign, usually an infinite loop. - if self.prev_token.kind == TokenKind::Eof { - let msg = "attempted to bump the parser past EOF (may be stuck in a loop)"; - self.span_bug(self.token.span, msg); - } - // Update the current and previous tokens. self.prev_token = mem::replace(&mut self.token, next_token); self.token_spacing = next_spacing; @@ -1035,8 +990,24 @@ impl<'a> Parser<'a> { /// Advance the parser by one token. pub fn bump(&mut self) { - let next_token = self.next_tok(self.token.span); - self.inlined_bump_with(next_token); + // Note: destructuring here would give nicer code, but it was found in #96210 to be slower + // than `.0`/`.1` access. + let mut next = self.token_cursor.inlined_next(self.desugar_doc_comments); + self.token_cursor.num_next_calls += 1; + // We've retrieved an token from the underlying + // cursor, so we no longer need to worry about + // an unglued token. See `break_and_eat` for more details + self.token_cursor.break_last_token = false; + if next.0.span.is_dummy() { + // Tweak the location for better diagnostics, but keep syntactic context intact. + let fallback_span = self.token.span; + next.0.span = fallback_span.with_ctxt(next.0.span.ctxt()); + } + debug_assert!(!matches!( + next.0.kind, + token::OpenDelim(Delimiter::Invisible) | token::CloseDelim(Delimiter::Invisible) + )); + self.inlined_bump_with(next) } /// Look-ahead `dist` tokens of `self.token` and get access to that token there. @@ -1047,10 +1018,10 @@ impl<'a> Parser<'a> { } let frame = &self.token_cursor.frame; - if frame.delim != DelimToken::NoDelim { + if let Some((delim, span)) = frame.delim_sp && delim != Delimiter::Invisible { let all_normal = (0..dist).all(|i| { let token = frame.tree_cursor.look_ahead(i); - !matches!(token, Some(TokenTree::Delimited(_, DelimToken::NoDelim, _))) + !matches!(token, Some(TokenTree::Delimited(_, Delimiter::Invisible, _))) }); if all_normal { return match frame.tree_cursor.look_ahead(dist - 1) { @@ -1060,7 +1031,7 @@ impl<'a> Parser<'a> { looker(&Token::new(token::OpenDelim(*delim), dspan.open)) } }, - None => looker(&Token::new(token::CloseDelim(frame.delim), frame.span.close)), + None => looker(&Token::new(token::CloseDelim(delim), span.close)), }; } } @@ -1069,10 +1040,10 @@ impl<'a> Parser<'a> { let mut i = 0; let mut token = Token::dummy(); while i < dist { - token = cursor.next().0; + token = cursor.next(/* desugar_doc_comments */ false).0; if matches!( token.kind, - token::OpenDelim(token::NoDelim) | token::CloseDelim(token::NoDelim) + token::OpenDelim(Delimiter::Invisible) | token::CloseDelim(Delimiter::Invisible) ) { continue; } @@ -1108,7 +1079,7 @@ impl<'a> Parser<'a> { /// Parses constness: `const` or nothing. fn parse_constness(&mut self) -> Const { // Avoid const blocks to be parsed as const items - if self.look_ahead(1, |t| t != &token::OpenDelim(DelimToken::Brace)) + if self.look_ahead(1, |t| t != &token::OpenDelim(Delimiter::Brace)) && self.eat_keyword(kw::Const) { Const::Yes(self.prev_token.uninterpolated_span()) @@ -1171,9 +1142,9 @@ impl<'a> Parser<'a> { fn parse_mac_args_common(&mut self, delimited_only: bool) -> PResult<'a, MacArgs> { Ok( - if self.check(&token::OpenDelim(DelimToken::Paren)) - || self.check(&token::OpenDelim(DelimToken::Bracket)) - || self.check(&token::OpenDelim(DelimToken::Brace)) + if self.check(&token::OpenDelim(Delimiter::Parenthesis)) + || self.check(&token::OpenDelim(Delimiter::Bracket)) + || self.check(&token::OpenDelim(Delimiter::Brace)) { match self.parse_token_tree() { TokenTree::Delimited(dspan, delim, tokens) => @@ -1217,24 +1188,27 @@ impl<'a> Parser<'a> { pub(crate) fn parse_token_tree(&mut self) -> TokenTree { match self.token.kind { token::OpenDelim(..) => { - let depth = self.token_cursor.stack.len(); - - // We keep advancing the token cursor until we hit - // the matching `CloseDelim` token. - while !(depth == self.token_cursor.stack.len() - && matches!(self.token.kind, token::CloseDelim(_))) - { + // Grab the tokens from this frame. + let frame = &self.token_cursor.frame; + let stream = frame.tree_cursor.stream.clone(); + let (delim, span) = frame.delim_sp.unwrap(); + + // Advance the token cursor through the entire delimited + // sequence. After getting the `OpenDelim` we are *within* the + // delimited sequence, i.e. at depth `d`. After getting the + // matching `CloseDelim` we are *after* the delimited sequence, + // i.e. at depth `d - 1`. + let target_depth = self.token_cursor.stack.len() - 1; + loop { // Advance one token at a time, so `TokenCursor::next()` // can capture these tokens if necessary. self.bump(); + if self.token_cursor.stack.len() == target_depth { + debug_assert!(matches!(self.token.kind, token::CloseDelim(_))); + break; + } } - // We are still inside the frame corresponding - // to the delimited stream we captured, so grab - // the tokens from this frame. - let frame = &self.token_cursor.frame; - let stream = frame.tree_cursor.stream.clone(); - let span = frame.span; - let delim = frame.delim; + // Consume close delimiter self.bump(); TokenTree::Delimited(span, delim, stream) @@ -1314,7 +1288,7 @@ impl<'a> Parser<'a> { } let lo = self.prev_token.span; - if self.check(&token::OpenDelim(token::Paren)) { + if self.check(&token::OpenDelim(Delimiter::Parenthesis)) { // We don't `self.bump()` the `(` yet because this might be a struct definition where // `()` or a tuple might be allowed. For example, `struct Struct(pub (), pub (usize));`. // Because of this, we only `bump` the `(` if we're assured it is appropriate to do so @@ -1325,7 +1299,7 @@ impl<'a> Parser<'a> { // Parse `pub(crate)`. self.bump(); // `(` self.bump(); // `crate` - self.expect(&token::CloseDelim(token::Paren))?; // `)` + self.expect(&token::CloseDelim(Delimiter::Parenthesis))?; // `)` let vis = VisibilityKind::Crate(CrateSugar::PubCrate); return Ok(Visibility { span: lo.to(self.prev_token.span), @@ -1337,20 +1311,20 @@ impl<'a> Parser<'a> { self.bump(); // `(` self.bump(); // `in` let path = self.parse_path(PathStyle::Mod)?; // `path` - self.expect(&token::CloseDelim(token::Paren))?; // `)` + self.expect(&token::CloseDelim(Delimiter::Parenthesis))?; // `)` let vis = VisibilityKind::Restricted { path: P(path), id: ast::DUMMY_NODE_ID }; return Ok(Visibility { span: lo.to(self.prev_token.span), kind: vis, tokens: None, }); - } else if self.look_ahead(2, |t| t == &token::CloseDelim(token::Paren)) + } else if self.look_ahead(2, |t| t == &token::CloseDelim(Delimiter::Parenthesis)) && self.is_keyword_ahead(1, &[kw::Super, kw::SelfLower]) { // Parse `pub(self)` or `pub(super)`. self.bump(); // `(` let path = self.parse_path(PathStyle::Mod)?; // `super`/`self` - self.expect(&token::CloseDelim(token::Paren))?; // `)` + self.expect(&token::CloseDelim(Delimiter::Parenthesis))?; // `)` let vis = VisibilityKind::Restricted { path: P(path), id: ast::DUMMY_NODE_ID }; return Ok(Visibility { span: lo.to(self.prev_token.span), @@ -1372,7 +1346,7 @@ impl<'a> Parser<'a> { fn recover_incorrect_vis_restriction(&mut self) -> PResult<'a, ()> { self.bump(); // `(` let path = self.parse_path(PathStyle::Mod)?; - self.expect(&token::CloseDelim(token::Paren))?; // `)` + self.expect(&token::CloseDelim(Delimiter::Parenthesis))?; // `)` let msg = "incorrect visibility restriction"; let suggestion = r##"some possible visibility restrictions are: @@ -1439,7 +1413,7 @@ impl<'a> Parser<'a> { fn is_import_coupler(&mut self) -> bool { self.check(&token::ModSep) && self.look_ahead(1, |t| { - *t == token::OpenDelim(token::Brace) || *t == token::BinOp(token::Star) + *t == token::OpenDelim(Delimiter::Brace) || *t == token::BinOp(token::Star) }) } |