1 //! The main parser interface.
3 #![feature(crate_visibility_modifier)]
4 #![feature(bindings_after_at)]
5 #![feature(iter_order_by)]
6 #![feature(or_patterns)]
9 use rustc_ast::attr::HasAttrs;
10 use rustc_ast::token::{self, Nonterminal};
11 use rustc_ast::tokenstream::{self, CanSynthesizeMissingTokens, LazyTokenStream, TokenStream};
12 use rustc_ast_pretty::pprust;
13 use rustc_data_structures::sync::Lrc;
14 use rustc_errors::{Diagnostic, FatalError, Level, PResult};
15 use rustc_session::parse::ParseSess;
16 use rustc_span::{FileName, SourceFile, Span};
23 pub const MACRO_ARGUMENTS: Option<&str> = Some("macro arguments");
27 use parser::{emit_unclosed_delims, make_unclosed_delims_error, Parser};
29 pub mod validate_attr;
31 // A bunch of utility functions of the form `parse_<thing>_from_<source>`
32 // where <thing> includes crate, expr, item, stmt, tts, and one that
33 // uses a HOF to parse anything, and <source> includes file and
36 /// A variant of 'panictry!' that works on a Vec<Diagnostic> instead of a single DiagnosticBuilder.
37 macro_rules! panictry_buffer {
38 ($handler:expr, $e:expr) => {{
39 use rustc_errors::FatalError;
40 use std::result::Result::{Err, Ok};
45 $handler.emit_diagnostic(&e);
53 pub fn parse_crate_from_file<'a>(input: &Path, sess: &'a ParseSess) -> PResult<'a, ast::Crate> {
54 let mut parser = new_parser_from_file(sess, input, None);
55 parser.parse_crate_mod()
58 pub fn parse_crate_attrs_from_file<'a>(
61 ) -> PResult<'a, Vec<ast::Attribute>> {
62 let mut parser = new_parser_from_file(sess, input, None);
63 parser.parse_inner_attributes()
66 pub fn parse_crate_from_source_str(
70 ) -> PResult<'_, ast::Crate> {
71 new_parser_from_source_str(sess, name, source).parse_crate_mod()
74 pub fn parse_crate_attrs_from_source_str(
78 ) -> PResult<'_, Vec<ast::Attribute>> {
79 new_parser_from_source_str(sess, name, source).parse_inner_attributes()
82 pub fn parse_stream_from_source_str(
86 override_span: Option<Span>,
88 let (stream, mut errors) =
89 source_file_to_stream(sess, sess.source_map().new_source_file(name, source), override_span);
90 emit_unclosed_delims(&mut errors, &sess);
94 /// Creates a new parser from a source string.
95 pub fn new_parser_from_source_str(sess: &ParseSess, name: FileName, source: String) -> Parser<'_> {
96 panictry_buffer!(&sess.span_diagnostic, maybe_new_parser_from_source_str(sess, name, source))
99 /// Creates a new parser from a source string. Returns any buffered errors from lexing the initial
101 pub fn maybe_new_parser_from_source_str(
105 ) -> Result<Parser<'_>, Vec<Diagnostic>> {
106 maybe_source_file_to_parser(sess, sess.source_map().new_source_file(name, source))
109 /// Creates a new parser, handling errors as appropriate if the file doesn't exist.
110 /// If a span is given, that is used on an error as the source of the problem.
111 pub fn new_parser_from_file<'a>(sess: &'a ParseSess, path: &Path, sp: Option<Span>) -> Parser<'a> {
112 source_file_to_parser(sess, file_to_source_file(sess, path, sp))
115 /// Given a `source_file` and config, returns a parser.
116 fn source_file_to_parser(sess: &ParseSess, source_file: Lrc<SourceFile>) -> Parser<'_> {
117 panictry_buffer!(&sess.span_diagnostic, maybe_source_file_to_parser(sess, source_file))
120 /// Given a `source_file` and config, return a parser. Returns any buffered errors from lexing the
121 /// initial token stream.
122 fn maybe_source_file_to_parser(
124 source_file: Lrc<SourceFile>,
125 ) -> Result<Parser<'_>, Vec<Diagnostic>> {
126 let end_pos = source_file.end_pos;
127 let (stream, unclosed_delims) = maybe_file_to_stream(sess, source_file, None)?;
128 let mut parser = stream_to_parser(sess, stream, None);
129 parser.unclosed_delims = unclosed_delims;
130 if parser.token == token::Eof {
131 parser.token.span = Span::new(end_pos, end_pos, parser.token.span.ctxt());
139 /// Given a session and a path and an optional span (for error reporting),
140 /// add the path to the session's source_map and return the new source_file or
141 /// error when a file can't be read.
142 fn try_file_to_source_file(
145 spanopt: Option<Span>,
146 ) -> Result<Lrc<SourceFile>, Diagnostic> {
147 sess.source_map().load_file(path).map_err(|e| {
148 let msg = format!("couldn't read {}: {}", path.display(), e);
149 let mut diag = Diagnostic::new(Level::Fatal, &msg);
150 if let Some(sp) = spanopt {
157 /// Given a session and a path and an optional span (for error reporting),
158 /// adds the path to the session's `source_map` and returns the new `source_file`.
159 fn file_to_source_file(sess: &ParseSess, path: &Path, spanopt: Option<Span>) -> Lrc<SourceFile> {
160 match try_file_to_source_file(sess, path, spanopt) {
161 Ok(source_file) => source_file,
163 sess.span_diagnostic.emit_diagnostic(&d);
169 /// Given a `source_file`, produces a sequence of token trees.
170 pub fn source_file_to_stream(
172 source_file: Lrc<SourceFile>,
173 override_span: Option<Span>,
174 ) -> (TokenStream, Vec<lexer::UnmatchedBrace>) {
175 panictry_buffer!(&sess.span_diagnostic, maybe_file_to_stream(sess, source_file, override_span))
178 /// Given a source file, produces a sequence of token trees. Returns any buffered errors from
179 /// parsing the token stream.
180 pub fn maybe_file_to_stream(
182 source_file: Lrc<SourceFile>,
183 override_span: Option<Span>,
184 ) -> Result<(TokenStream, Vec<lexer::UnmatchedBrace>), Vec<Diagnostic>> {
185 let src = source_file.src.as_ref().unwrap_or_else(|| {
187 .bug(&format!("cannot lex `source_file` without source: {}", source_file.name));
190 let (token_trees, unmatched_braces) =
191 lexer::parse_token_trees(sess, src.as_str(), source_file.start_pos, override_span);
194 Ok(stream) => Ok((stream, unmatched_braces)),
196 let mut buffer = Vec::with_capacity(1);
197 err.buffer(&mut buffer);
198 // Not using `emit_unclosed_delims` to use `db.buffer`
199 for unmatched in unmatched_braces {
200 if let Some(err) = make_unclosed_delims_error(unmatched, &sess) {
201 err.buffer(&mut buffer);
209 /// Given a stream and the `ParseSess`, produces a parser.
210 pub fn stream_to_parser<'a>(
213 subparser_name: Option<&'static str>,
215 Parser::new(sess, stream, false, subparser_name)
218 /// Runs the given subparser `f` on the tokens of the given `attr`'s item.
219 pub fn parse_in<'a, T>(
223 mut f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>,
224 ) -> PResult<'a, T> {
225 let mut parser = Parser::new(sess, tts, false, Some(name));
226 let result = f(&mut parser)?;
227 if parser.token != token::Eof {
228 parser.unexpected()?;
233 // NOTE(Centril): The following probably shouldn't be here but it acknowledges the
234 // fact that architecturally, we are using parsing (read on below to understand why).
236 pub fn nt_to_tokenstream(
240 synthesize_tokens: CanSynthesizeMissingTokens,
242 // A `Nonterminal` is often a parsed AST item. At this point we now
243 // need to convert the parsed AST to an actual token stream, e.g.
244 // un-parse it basically.
246 // Unfortunately there's not really a great way to do that in a
247 // guaranteed lossless fashion right now. The fallback here is to just
248 // stringify the AST node and reparse it, but this loses all span
251 // As a result, some AST nodes are annotated with the token stream they
252 // came from. Here we attempt to extract these lossless token streams
253 // before we fall back to the stringification.
256 |tokens: Option<&LazyTokenStream>| tokens.as_ref().map(|t| t.create_token_stream());
258 let tokens = match *nt {
259 Nonterminal::NtItem(ref item) => {
260 prepend_attrs(sess, &item.attrs, nt, span, item.tokens.as_ref())
262 Nonterminal::NtBlock(ref block) => convert_tokens(block.tokens.as_ref()),
263 Nonterminal::NtStmt(ref stmt) => prepend_attrs(sess, stmt.attrs(), nt, span, stmt.tokens()),
264 Nonterminal::NtPat(ref pat) => convert_tokens(pat.tokens.as_ref()),
265 Nonterminal::NtTy(ref ty) => convert_tokens(ty.tokens.as_ref()),
266 Nonterminal::NtIdent(ident, is_raw) => {
267 Some(tokenstream::TokenTree::token(token::Ident(ident.name, is_raw), ident.span).into())
269 Nonterminal::NtLifetime(ident) => {
270 Some(tokenstream::TokenTree::token(token::Lifetime(ident.name), ident.span).into())
272 Nonterminal::NtMeta(ref attr) => convert_tokens(attr.tokens.as_ref()),
273 Nonterminal::NtPath(ref path) => convert_tokens(path.tokens.as_ref()),
274 Nonterminal::NtVis(ref vis) => convert_tokens(vis.tokens.as_ref()),
275 Nonterminal::NtTT(ref tt) => Some(tt.clone().into()),
276 Nonterminal::NtExpr(ref expr) | Nonterminal::NtLiteral(ref expr) => {
277 if expr.tokens.is_none() {
278 debug!("missing tokens for expr {:?}", expr);
280 prepend_attrs(sess, &expr.attrs, nt, span, expr.tokens.as_ref())
284 if let Some(tokens) = tokens {
286 } else if matches!(synthesize_tokens, CanSynthesizeMissingTokens::Yes) {
287 return fake_token_stream(sess, nt, span);
289 let pretty = rustc_ast_pretty::pprust::nonterminal_to_string_no_extra_parens(&nt);
290 panic!("Missing tokens at {:?} for nt {:?}", span, pretty);
294 pub fn fake_token_stream(sess: &ParseSess, nt: &Nonterminal, span: Span) -> TokenStream {
295 let source = pprust::nonterminal_to_string(nt);
296 let filename = FileName::macro_expansion_source_code(&source);
297 parse_stream_from_source_str(filename, source, sess, Some(span))
302 attrs: &[ast::Attribute],
305 tokens: Option<&tokenstream::LazyTokenStream>,
306 ) -> Option<tokenstream::TokenStream> {
307 if attrs.is_empty() {
308 return Some(tokens?.create_token_stream());
310 let mut builder = tokenstream::TokenStreamBuilder::new();
312 // FIXME: Correctly handle tokens for inner attributes.
313 // For now, we fall back to reparsing the original AST node
314 if attr.style == ast::AttrStyle::Inner {
315 return Some(fake_token_stream(sess, nt, span));
317 builder.push(attr.tokens());
319 builder.push(tokens?.create_token_stream());
320 Some(builder.build())