compiler/rustc_builtin_macros/src/source_util.rs

   1 use rustc_ast as ast;
   2 use rustc_ast::ptr::P;
   3 use rustc_ast::token;
   4 use rustc_ast::tokenstream::TokenStream;
   5 use rustc_ast_pretty::pprust;
   6 use rustc_expand::base::{self, *};
   7 use rustc_expand::module::DirOwnership;
   8 use rustc_parse::parser::{ForceCollect, Parser};
   9 use rustc_parse::{self, new_parser_from_file};
  10 use rustc_session::lint::builtin::INCOMPLETE_INCLUDE;
  11 use rustc_span::symbol::Symbol;
  12 use rustc_span::{self, Pos, Span};
  13
  14 use smallvec::SmallVec;
  15 use std::rc::Rc;
  16
  17 // These macros all relate to the file system; they either return
  18 // the column/row/filename of the expression, or they include
  19 // a given file into the current one.
  20
  21 /// line!(): expands to the current line number
  22 pub fn expand_line(
  23     cx: &mut ExtCtxt<'_>,
  24     sp: Span,
  25     tts: TokenStream,
  26 ) -> Box<dyn base::MacResult + 'static> {
  27     let sp = cx.with_def_site_ctxt(sp);
  28     base::check_zero_tts(cx, sp, tts, "line!");
  29
  30     let topmost = cx.expansion_cause().unwrap_or(sp);
  31     let loc = cx.source_map().lookup_char_pos(topmost.lo());
  32
  33     base::MacEager::expr(cx.expr_u32(topmost, loc.line as u32))
  34 }
  35
  36 /* column!(): expands to the current column number */
  37 pub fn expand_column(
  38     cx: &mut ExtCtxt<'_>,
  39     sp: Span,
  40     tts: TokenStream,
  41 ) -> Box<dyn base::MacResult + 'static> {
  42     let sp = cx.with_def_site_ctxt(sp);
  43     base::check_zero_tts(cx, sp, tts, "column!");
  44
  45     let topmost = cx.expansion_cause().unwrap_or(sp);
  46     let loc = cx.source_map().lookup_char_pos(topmost.lo());
  47
  48     base::MacEager::expr(cx.expr_u32(topmost, loc.col.to_usize() as u32 + 1))
  49 }
  50
  51 /// file!(): expands to the current filename */
  52 /// The source_file (`loc.file`) contains a bunch more information we could spit
  53 /// out if we wanted.
  54 pub fn expand_file(
  55     cx: &mut ExtCtxt<'_>,
  56     sp: Span,
  57     tts: TokenStream,
  58 ) -> Box<dyn base::MacResult + 'static> {
  59     let sp = cx.with_def_site_ctxt(sp);
  60     base::check_zero_tts(cx, sp, tts, "file!");
  61
  62     let topmost = cx.expansion_cause().unwrap_or(sp);
  63     let loc = cx.source_map().lookup_char_pos(topmost.lo());
  64     base::MacEager::expr(
  65         cx.expr_str(topmost, Symbol::intern(&loc.file.name.prefer_remapped().to_string_lossy())),
  66     )
  67 }
  68
  69 pub fn expand_stringify(
  70     cx: &mut ExtCtxt<'_>,
  71     sp: Span,
  72     tts: TokenStream,
  73 ) -> Box<dyn base::MacResult + 'static> {
  74     let sp = cx.with_def_site_ctxt(sp);
  75     let s = pprust::tts_to_string(&tts);
  76     base::MacEager::expr(cx.expr_str(sp, Symbol::intern(&s)))
  77 }
  78
  79 pub fn expand_mod(
  80     cx: &mut ExtCtxt<'_>,
  81     sp: Span,
  82     tts: TokenStream,
  83 ) -> Box<dyn base::MacResult + 'static> {
  84     let sp = cx.with_def_site_ctxt(sp);
  85     base::check_zero_tts(cx, sp, tts, "module_path!");
  86     let mod_path = &cx.current_expansion.module.mod_path;
  87     let string = mod_path.iter().map(|x| x.to_string()).collect::<Vec<String>>().join("::");
  88
  89     base::MacEager::expr(cx.expr_str(sp, Symbol::intern(&string)))
  90 }
  91
  92 /// include! : parse the given file as an expr
  93 /// This is generally a bad idea because it's going to behave
  94 /// unhygienically.
  95 pub fn expand_include<'cx>(
  96     cx: &'cx mut ExtCtxt<'_>,
  97     sp: Span,
  98     tts: TokenStream,
  99 ) -> Box<dyn base::MacResult + 'cx> {
 100     let sp = cx.with_def_site_ctxt(sp);
 101     let Some(file) = get_single_str_from_tts(cx, sp, tts, "include!") else {
 102         return DummyResult::any(sp);
 103     };
 104     // The file will be added to the code map by the parser
 105     let file = match resolve_path(&cx.sess.parse_sess, file.as_str(), sp) {
 106         Ok(f) => f,
 107         Err(mut err) => {
 108             err.emit();
 109             return DummyResult::any(sp);
 110         }
 111     };
 112     let p = new_parser_from_file(cx.parse_sess(), &file, Some(sp));
 113
 114     // If in the included file we have e.g., `mod bar;`,
 115     // then the path of `bar.rs` should be relative to the directory of `file`.
 116     // See https://github.com/rust-lang/rust/pull/69838/files#r395217057 for a discussion.
 117     // `MacroExpander::fully_expand_fragment` later restores, so "stack discipline" is maintained.
 118     let dir_path = file.parent().unwrap_or(&file).to_owned();
 119     cx.current_expansion.module = Rc::new(cx.current_expansion.module.with_dir_path(dir_path));
 120     cx.current_expansion.dir_ownership = DirOwnership::Owned { relative: None };
 121
 122     struct ExpandResult<'a> {
 123         p: Parser<'a>,
 124         node_id: ast::NodeId,
 125     }
 126     impl<'a> base::MacResult for ExpandResult<'a> {
 127         fn make_expr(mut self: Box<ExpandResult<'a>>) -> Option<P<ast::Expr>> {
 128             let r = base::parse_expr(&mut self.p)?;
 129             if self.p.token != token::Eof {
 130                 self.p.sess.buffer_lint(
 131                     &INCOMPLETE_INCLUDE,
 132                     self.p.token.span,
 133                     self.node_id,
 134                     "include macro expected single expression in source",
 135                 );
 136             }
 137             Some(r)
 138         }
 139
 140         fn make_items(mut self: Box<ExpandResult<'a>>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
 141             let mut ret = SmallVec::new();
 142             loop {
 143                 match self.p.parse_item(ForceCollect::No) {
 144                     Err(mut err) => {
 145                         err.emit();
 146                         break;
 147                     }
 148                     Ok(Some(item)) => ret.push(item),
 149                     Ok(None) => {
 150                         if self.p.token != token::Eof {
 151                             let token = pprust::token_to_string(&self.p.token);
 152                             let msg = format!("expected item, found `{}`", token);
 153                             self.p.struct_span_err(self.p.token.span, &msg).emit();
 154                         }
 155
 156                         break;
 157                     }
 158                 }
 159             }
 160             Some(ret)
 161         }
 162     }
 163
 164     Box::new(ExpandResult { p, node_id: cx.current_expansion.lint_node_id })
 165 }
 166
 167 /// `include_str!`: read the given file, insert it as a literal string expr
 168 pub fn expand_include_str(
 169     cx: &mut ExtCtxt<'_>,
 170     sp: Span,
 171     tts: TokenStream,
 172 ) -> Box<dyn base::MacResult + 'static> {
 173     let sp = cx.with_def_site_ctxt(sp);
 174     let Some(file) = get_single_str_from_tts(cx, sp, tts, "include_str!") else {
 175         return DummyResult::any(sp);
 176     };
 177     let file = match resolve_path(&cx.sess.parse_sess, file.as_str(), sp) {
 178         Ok(f) => f,
 179         Err(mut err) => {
 180             err.emit();
 181             return DummyResult::any(sp);
 182         }
 183     };
 184     match cx.source_map().load_binary_file(&file) {
 185         Ok(bytes) => match std::str::from_utf8(&bytes) {
 186             Ok(src) => {
 187                 let interned_src = Symbol::intern(&src);
 188                 base::MacEager::expr(cx.expr_str(sp, interned_src))
 189             }
 190             Err(_) => {
 191                 cx.span_err(sp, &format!("{} wasn't a utf-8 file", file.display()));
 192                 DummyResult::any(sp)
 193             }
 194         },
 195         Err(e) => {
 196             cx.span_err(sp, &format!("couldn't read {}: {}", file.display(), e));
 197             DummyResult::any(sp)
 198         }
 199     }
 200 }
 201
 202 pub fn expand_include_bytes(
 203     cx: &mut ExtCtxt<'_>,
 204     sp: Span,
 205     tts: TokenStream,
 206 ) -> Box<dyn base::MacResult + 'static> {
 207     let sp = cx.with_def_site_ctxt(sp);
 208     let Some(file) = get_single_str_from_tts(cx, sp, tts, "include_bytes!") else {
 209         return DummyResult::any(sp);
 210     };
 211     let file = match resolve_path(&cx.sess.parse_sess, file.as_str(), sp) {
 212         Ok(f) => f,
 213         Err(mut err) => {
 214             err.emit();
 215             return DummyResult::any(sp);
 216         }
 217     };
 218     match cx.source_map().load_binary_file(&file) {
 219         Ok(bytes) => {
 220             let expr = cx.expr(sp, ast::ExprKind::IncludedBytes(bytes.into()));
 221             base::MacEager::expr(expr)
 222         }
 223         Err(e) => {
 224             cx.span_err(sp, &format!("couldn't read {}: {}", file.display(), e));
 225             DummyResult::any(sp)
 226         }
 227     }
 228 }