Auto merge of rust-lang#83813 - cbeuw:remap-std, r=michaelwoerister

Fix `--remap-path-prefix` not correctly remapping `rust-src` component paths and unify handling of path mapping with virtualized paths

This PR fixes rust-lang#73167 ("Binaries end up containing path to the rust-src component despite `--remap-path-prefix`") by preventing real local filesystem paths from reaching compilation output if the path is supposed to be remapped.

`RealFileName::Named` introduced in rust-lang#72767 is now renamed as `LocalPath`, because this variant wraps a (most likely) valid local filesystem path.

`RealFileName::Devirtualized` is renamed as `Remapped` to be used for remapped path from a real path via `--remap-path-prefix` argument, as well as real path inferred from a virtualized (during compiler bootstrapping) `/rustc/...` path. The `local_path` field is now an `Option<PathBuf>`, as it will be set to `None` before serialisation, so it never reaches any build output. Attempting to serialise a non-`None` `local_path` will cause an assertion faliure.

When a path is remapped, a `RealFileName::Remapped` variant is created. The original path is preserved in `local_path` field and the remapped path is saved in `virtual_name` field. Previously, the `local_path` is directly modified which goes against its purpose of "suitable for reading from the file system on the local host".

`rustc_span::SourceFile`'s fields `unmapped_path` (introduced by rust-lang#44940) and `name_was_remapped` (introduced by rust-lang#41508 when `--remap-path-prefix` feature originally added) are removed, as these two pieces of information can be inferred from the `name` field: if it's anything other than a `FileName::Real(_)`, or if it is a `FileName::Real(RealFileName::LocalPath(_))`, then clearly `name_was_remapped` would've been false and `unmapped_path` would've been `None`. If it is a `FileName::Real(RealFileName::Remapped{local_path, virtual_name})`, then `name_was_remapped` would've been true and `unmapped_path` would've been `Some(local_path)`.

cc `@eddyb` who implemented `/rustc/...` path devirtualisation

Author: bors

compiler/rustc_builtin_macros/src/source_util.rs

@@ -61,7 +61,9 @@ pub fn expand_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.to_string())))
+    base::MacEager::expr(
+        cx.expr_str(topmost, Symbol::intern(&loc.file.name.prefer_remapped().to_string_lossy())),
+    )
 }
 
 pub fn expand_stringify(

compiler/rustc_codegen_cranelift/src/common.rs

@@ -334,7 +334,9 @@ impl<'tcx> FunctionCx<'_, '_, 'tcx> {
         let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span);
         let caller = self.tcx.sess.source_map().lookup_char_pos(topmost.lo());
         let const_loc = self.tcx.const_caller_location((
-            rustc_span::symbol::Symbol::intern(&caller.file.name.to_string()),
+            rustc_span::symbol::Symbol::intern(
+                &caller.file.name.prefer_remapped().to_string_lossy(),
+            ),
             caller.line as u32,
             caller.col_display as u32 + 1,
         ));

compiler/rustc_codegen_cranelift/src/debuginfo/line_info.rs

@@ -66,7 +66,7 @@ fn line_program_add_file(
 ) -> FileId {
     match &file.name {
         FileName::Real(path) => {
-            let (dir_path, file_name) = split_path_dir_and_file(path.stable_name());
+            let (dir_path, file_name) = split_path_dir_and_file(path.remapped_path_if_available());
             let dir_name = osstr_as_utf8_bytes(dir_path.as_os_str());
             let file_name = osstr_as_utf8_bytes(file_name);
 
@@ -87,7 +87,7 @@ fn line_program_add_file(
         filename => {
             let dir_id = line_program.default_directory();
             let dummy_file_name = LineString::new(
-                filename.to_string().into_bytes(),
+                filename.prefer_remapped().to_string().into_bytes(),
                 line_program.encoding(),
                 line_strings,
             );

compiler/rustc_codegen_cranelift/src/debuginfo/mod.rs

@@ -64,7 +64,7 @@ impl<'tcx> DebugContext<'tcx> {
         // FIXME: how to get version when building out of tree?
         // Normally this would use option_env!("CFG_VERSION").
         let producer = format!("cg_clif (rustc {})", "unknown version");
-        let comp_dir = tcx.sess.working_dir.0.to_string_lossy().into_owned();
+        let comp_dir = tcx.sess.working_dir.to_string_lossy(false).into_owned();
         let (name, file_info) = match tcx.sess.local_crate_source_file.clone() {
             Some(path) => {
                 let name = path.to_string_lossy().into_owned();

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -760,12 +760,12 @@ fn hex_encode(data: &[u8]) -> String {
 }
 
 pub fn file_metadata(cx: &CodegenCx<'ll, '_>, source_file: &SourceFile) -> &'ll DIFile {
-    debug!("file_metadata: file_name: {}", source_file.name);
+    debug!("file_metadata: file_name: {:?}", source_file.name);
 
     let hash = Some(&source_file.src_hash);
-    let file_name = Some(source_file.name.to_string());
+    let file_name = Some(source_file.name.prefer_remapped().to_string());
     let directory = if source_file.is_real_file() && !source_file.is_imported() {
-        Some(cx.sess().working_dir.0.to_string_lossy().to_string())
+        Some(cx.sess().working_dir.to_string_lossy(false).to_string())
     } else {
         // If the path comes from an upstream crate we assume it has been made
         // independent of the compiler's working directory one way or another.
@@ -993,7 +993,7 @@ pub fn compile_unit_metadata(
     let producer = format!("clang LLVM ({})", rustc_producer);
 
     let name_in_debuginfo = name_in_debuginfo.to_string_lossy();
-    let work_dir = tcx.sess.working_dir.0.to_string_lossy();
+    let work_dir = tcx.sess.working_dir.to_string_lossy(false);
     let flags = "\0";
     let out_dir = &tcx.output_filenames(LOCAL_CRATE).out_directory;
     let split_name = if tcx.sess.target_can_use_split_dwarf() {

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -1144,7 +1144,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span);
             let caller = tcx.sess.source_map().lookup_char_pos(topmost.lo());
             let const_loc = tcx.const_caller_location((
-                Symbol::intern(&caller.file.name.to_string()),
+                Symbol::intern(&caller.file.name.prefer_remapped().to_string_lossy()),
                 caller.line as u32,
                 caller.col_display as u32 + 1,
             ));

compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs

@@ -126,7 +126,8 @@ impl AnnotateSnippetEmitterWriter {
             }
             // owned: line source, line index, annotations
             type Owned = (String, usize, Vec<crate::snippet::Annotation>);
-            let origin = primary_lo.file.name.to_string();
+            let filename = primary_lo.file.name.prefer_local();
+            let origin = filename.to_string_lossy();
             let annotated_files: Vec<Owned> = annotated_files
                 .into_iter()
                 .flat_map(|annotated_file| {

compiler/rustc_errors/src/emitter.rs

@@ -1324,7 +1324,7 @@ impl EmitterWriter {
                         buffer_msg_line_offset,
                         &format!(
                             "{}:{}:{}",
-                            loc.file.name,
+                            loc.file.name.prefer_local(),
                             sm.doctest_offset_line(&loc.file.name, loc.line),
                             loc.col.0 + 1,
                         ),
@@ -1338,7 +1338,7 @@ impl EmitterWriter {
                         0,
                         &format!(
                             "{}:{}:{}: ",
-                            loc.file.name,
+                            loc.file.name.prefer_local(),
                             sm.doctest_offset_line(&loc.file.name, loc.line),
                             loc.col.0 + 1,
                         ),
@@ -1362,12 +1362,12 @@ impl EmitterWriter {
                     };
                     format!(
                         "{}:{}{}",
-                        annotated_file.file.name,
+                        annotated_file.file.name.prefer_local(),
                         sm.doctest_offset_line(&annotated_file.file.name, first_line.line_index),
                         col
                     )
                 } else {
-                    annotated_file.file.name.to_string()
+                    format!("{}", annotated_file.file.name.prefer_local())
                 };
                 buffer.append(buffer_msg_line_offset + 1, &loc, Style::LineAndColumn);
                 for _ in 0..max_line_num_len {

compiler/rustc_errors/src/json.rs

@@ -468,7 +468,7 @@ impl DiagnosticSpan {
         });
 
         DiagnosticSpan {
-            file_name: start.file.name.to_string(),
+            file_name: start.file.name.prefer_local().to_string(),
             byte_start: start.file.original_relative_byte_pos(span.lo()).0,
             byte_end: start.file.original_relative_byte_pos(span.hi()).0,
             line_start: start.line,

compiler/rustc_expand/src/base.rs

@@ -1084,13 +1084,18 @@ impl<'a> ExtCtxt<'a> {
         // after macro expansion (that is, they are unhygienic).
         if !path.is_absolute() {
             let callsite = span.source_callsite();
-            let mut result = match self.source_map().span_to_unmapped_path(callsite) {
-                FileName::Real(name) => name.into_local_path(),
+            let mut result = match self.source_map().span_to_filename(callsite) {
+                FileName::Real(name) => name
+                    .into_local_path()
+                    .expect("attempting to resolve a file path in an external file"),
                 FileName::DocTest(path, _) => path,
                 other => {
                     return Err(self.struct_span_err(
                         span,
-                        &format!("cannot resolve relative path in non-file source `{}`", other),
+                        &format!(
+                            "cannot resolve relative path in non-file source `{}`",
+                            other.prefer_local()
+                        ),
                     ));
                 }
             };