1 files changed, 225 insertions, 0 deletions
diff --git a/compiler/rustc_builtin_macros/src/source_util.rs b/compiler/rustc_builtin_macros/src/source_util.rs
new file mode 100644
index 000000000..8bf3a0799
--- /dev/null
+++ b/compiler/rustc_builtin_macros/src/source_util.rs
@@ -0,0 +1,225 @@
+use rustc_ast as ast;
+use rustc_ast::ptr::P;
+use rustc_ast::token;
+use rustc_ast::tokenstream::TokenStream;
+use rustc_ast_pretty::pprust;
+use rustc_expand::base::{self, *};
+use rustc_expand::module::DirOwnership;
+use rustc_parse::parser::{ForceCollect, Parser};
+use rustc_parse::{self, new_parser_from_file};
+use rustc_session::lint::builtin::INCOMPLETE_INCLUDE;
+use rustc_span::symbol::Symbol;
+use rustc_span::{self, Pos, Span};
+
+use smallvec::SmallVec;
+use std::rc::Rc;
+
+// These macros all relate to the file system; they either return
+// the column/row/filename of the expression, or they include
+// a given file into the current one.
+
+/// line!(): expands to the current line number
+pub fn expand_line(
+    cx: &mut ExtCtxt<'_>,
+    sp: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'static> {
+    let sp = cx.with_def_site_ctxt(sp);
+    base::check_zero_tts(cx, sp, tts, "line!");
+
+    let topmost = cx.expansion_cause().unwrap_or(sp);
+    let loc = cx.source_map().lookup_char_pos(topmost.lo());
+
+    base::MacEager::expr(cx.expr_u32(topmost, loc.line as u32))
+}
+
+/* column!(): expands to the current column number */
+pub fn expand_column(
+    cx: &mut ExtCtxt<'_>,
+    sp: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'static> {
+    let sp = cx.with_def_site_ctxt(sp);
+    base::check_zero_tts(cx, sp, tts, "column!");
+
+    let topmost = cx.expansion_cause().unwrap_or(sp);
+    let loc = cx.source_map().lookup_char_pos(topmost.lo());
+
+    base::MacEager::expr(cx.expr_u32(topmost, loc.col.to_usize() as u32 + 1))
+}
+
+/// file!(): expands to the current filename */
+/// The source_file (`loc.file`) contains a bunch more information we could spit
+/// out if we wanted.
+pub fn expand_file(
+    cx: &mut ExtCtxt<'_>,
+    sp: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'static> {
+    let sp = cx.with_def_site_ctxt(sp);
+    base::check_zero_tts(cx, sp, tts, "file!");
+
+    let topmost = cx.expansion_cause().unwrap_or(sp);
+    let loc = cx.source_map().lookup_char_pos(topmost.lo());
+    base::MacEager::expr(
+        cx.expr_str(topmost, Symbol::intern(&loc.file.name.prefer_remapped().to_string_lossy())),
+    )
+}
+
+pub fn expand_stringify(
+    cx: &mut ExtCtxt<'_>,
+    sp: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'static> {
+    let sp = cx.with_def_site_ctxt(sp);
+    let s = pprust::tts_to_string(&tts);
+    base::MacEager::expr(cx.expr_str(sp, Symbol::intern(&s)))
+}
+
+pub fn expand_mod(
+    cx: &mut ExtCtxt<'_>,
+    sp: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'static> {
+    let sp = cx.with_def_site_ctxt(sp);
+    base::check_zero_tts(cx, sp, tts, "module_path!");
+    let mod_path = &cx.current_expansion.module.mod_path;
+    let string = mod_path.iter().map(|x| x.to_string()).collect::<Vec<String>>().join("::");
+
+    base::MacEager::expr(cx.expr_str(sp, Symbol::intern(&string)))
+}
+
+/// include! : parse the given file as an expr
+/// This is generally a bad idea because it's going to behave
+/// unhygienically.
+pub fn expand_include<'cx>(
+    cx: &'cx mut ExtCtxt<'_>,
+    sp: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'cx> {
+    let sp = cx.with_def_site_ctxt(sp);
+    let Some(file) = get_single_str_from_tts(cx, sp, tts, "include!") else {
+        return DummyResult::any(sp);
+    };
+    // The file will be added to the code map by the parser
+    let file = match resolve_path(&cx.sess.parse_sess, file.as_str(), sp) {
+        Ok(f) => f,
+        Err(mut err) => {
+            err.emit();
+            return DummyResult::any(sp);
+        }
+    };
+    let p = new_parser_from_file(cx.parse_sess(), &file, Some(sp));
+
+    // If in the included file we have e.g., `mod bar;`,
+    // then the path of `bar.rs` should be relative to the directory of `file`.
+    // See https://github.com/rust-lang/rust/pull/69838/files#r395217057 for a discussion.
+    // `MacroExpander::fully_expand_fragment` later restores, so "stack discipline" is maintained.
+    let dir_path = file.parent().unwrap_or(&file).to_owned();
+    cx.current_expansion.module = Rc::new(cx.current_expansion.module.with_dir_path(dir_path));
+    cx.current_expansion.dir_ownership = DirOwnership::Owned { relative: None };
+
+    struct ExpandResult<'a> {
+        p: Parser<'a>,
+        node_id: ast::NodeId,
+    }
+    impl<'a> base::MacResult for ExpandResult<'a> {
+        fn make_expr(mut self: Box<ExpandResult<'a>>) -> Option<P<ast::Expr>> {
+            let r = base::parse_expr(&mut self.p)?;
+            if self.p.token != token::Eof {
+                self.p.sess.buffer_lint(
+                    &INCOMPLETE_INCLUDE,
+                    self.p.token.span,
+                    self.node_id,
+                    "include macro expected single expression in source",
+                );
+            }
+            Some(r)
+        }
+
+        fn make_items(mut self: Box<ExpandResult<'a>>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
+            let mut ret = SmallVec::new();
+            loop {
+                match self.p.parse_item(ForceCollect::No) {
+                    Err(mut err) => {
+                        err.emit();
+                        break;
+                    }
+                    Ok(Some(item)) => ret.push(item),
+                    Ok(None) => {
+                        if self.p.token != token::Eof {
+                            let token = pprust::token_to_string(&self.p.token);
+                            let msg = format!("expected item, found `{}`", token);
+                            self.p.struct_span_err(self.p.token.span, &msg).emit();
+                        }
+
+                        break;
+                    }
+                }
+            }
+            Some(ret)
+        }
+    }
+
+    Box::new(ExpandResult { p, node_id: cx.current_expansion.lint_node_id })
+}
+
+// include_str! : read the given file, insert it as a literal string expr
+pub fn expand_include_str(
+    cx: &mut ExtCtxt<'_>,
+    sp: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'static> {
+    let sp = cx.with_def_site_ctxt(sp);
+    let Some(file) = get_single_str_from_tts(cx, sp, tts, "include_str!") else {
+        return DummyResult::any(sp);
+    };
+    let file = match resolve_path(&cx.sess.parse_sess, file.as_str(), sp) {
+        Ok(f) => f,
+        Err(mut err) => {
+            err.emit();
+            return DummyResult::any(sp);
+        }
+    };
+    match cx.source_map().load_binary_file(&file) {
+        Ok(bytes) => match std::str::from_utf8(&bytes) {
+            Ok(src) => {
+                let interned_src = Symbol::intern(&src);
+                base::MacEager::expr(cx.expr_str(sp, interned_src))
+            }
+            Err(_) => {
+                cx.span_err(sp, &format!("{} wasn't a utf-8 file", file.display()));
+                DummyResult::any(sp)
+            }
+        },
+        Err(e) => {
+            cx.span_err(sp, &format!("couldn't read {}: {}", file.display(), e));
+            DummyResult::any(sp)
+        }
+    }
+}
+
+pub fn expand_include_bytes(
+    cx: &mut ExtCtxt<'_>,
+    sp: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'static> {
+    let sp = cx.with_def_site_ctxt(sp);
+    let Some(file) = get_single_str_from_tts(cx, sp, tts, "include_bytes!") else {
+        return DummyResult::any(sp);
+    };
+    let file = match resolve_path(&cx.sess.parse_sess, file.as_str(), sp) {
+        Ok(f) => f,
+        Err(mut err) => {
+            err.emit();
+            return DummyResult::any(sp);
+        }
+    };
+    match cx.source_map().load_binary_file(&file) {
+        Ok(bytes) => base::MacEager::expr(cx.expr_lit(sp, ast::LitKind::ByteStr(bytes.into()))),
+        Err(e) => {
+            cx.span_err(sp, &format!("couldn't read {}: {}", file.display(), e));
+            DummyResult::any(sp)
+        }
+    }
+}