Make cargo aware of dwp files.

When using -Csplit-debuginfo=packed on Linux, rustc will produce a dwp file.
Unlike the dwo files, whose paths are embedded into the binary, there's no
information in the binary to help a debugger locate a dwp file. By convention,
the dwp file for <EXE> is given the name <EXE>.dwp and placed next to <EXE>.

When cargo hardlinks the executable file rustc put in target/debug/deps into
target/debug, it also needs to hardlink the dwp file along with it. Failing to
do this prevents the debugger from finding the dwp file when the binary is
executed from target/debug, as there's no way for the debugger to know to look
in the deps subdirectory.

The split_debuginfo option is passed down into file_types to make this possible.
For cargo clean manual handling is added to match the other split_debuginfo
files. bin_link_for_target also passes in None because it won't care about the
dwp file.

Author: khuey

src/cargo/core/compiler/build_context/target_info.rs

@@ -333,6 +333,7 @@ impl TargetInfo {
         crate_type: &CrateType,
         flavor: FileFlavor,
         target_triple: &str,
+        split_debuginfo: Option<&str>,
     ) -> CargoResult<Option<Vec<FileType>>> {
         let crate_type = if *crate_type == CrateType::Lib {
             CrateType::Rlib
@@ -462,6 +463,14 @@ impl TargetInfo {
                     // preserved.
                     should_replace_hyphens: true,
                 })
+            } else if split_debuginfo == Some("packed") {
+                ret.push(FileType {
+                    suffix: ".dwp".to_string(),
+                    prefix: prefix.clone(),
+                    flavor: FileFlavor::DebugInfo,
+                    crate_type: Some(crate_type),
+                    should_replace_hyphens: false,
+                })
             }
         }
 
@@ -494,11 +503,19 @@ impl TargetInfo {
         mode: CompileMode,
         target_kind: &TargetKind,
         target_triple: &str,
+        split_debuginfo: Option<&str>,
     ) -> CargoResult<(Vec<FileType>, Vec<CrateType>)> {
         match mode {
-            CompileMode::Build => self.calc_rustc_outputs(target_kind, target_triple),
+            CompileMode::Build => {
+                self.calc_rustc_outputs(target_kind, target_triple, split_debuginfo)
+            }
             CompileMode::Test | CompileMode::Bench => {
-                match self.file_types(&CrateType::Bin, FileFlavor::Normal, target_triple)? {
+                match self.file_types(
+                    &CrateType::Bin,
+                    FileFlavor::Normal,
+                    target_triple,
+                    split_debuginfo,
+                )? {
                     Some(fts) => Ok((fts, Vec::new())),
                     None => Ok((Vec::new(), vec![CrateType::Bin])),
                 }
@@ -517,6 +534,7 @@ impl TargetInfo {
         &self,
         target_kind: &TargetKind,
         target_triple: &str,
+        split_debuginfo: Option<&str>,
     ) -> CargoResult<(Vec<FileType>, Vec<CrateType>)> {
         let mut unsupported = Vec::new();
         let mut result = Vec::new();
@@ -527,7 +545,7 @@ impl TargetInfo {
             } else {
                 FileFlavor::Normal
             };
-            let file_types = self.file_types(crate_type, flavor, target_triple)?;
+            let file_types = self.file_types(crate_type, flavor, target_triple, split_debuginfo)?;
             match file_types {
                 Some(types) => {
                     result.extend(types);

src/cargo/core/compiler/context/compilation_files.rs

@@ -346,6 +346,7 @@ impl<'a, 'cfg: 'a> CompilationFiles<'a, 'cfg> {
                 CompileMode::Build,
                 &TargetKind::Bin,
                 bcx.target_data.short_name(&kind),
+                None,
             )
             .expect("target must support `bin`");
 
@@ -486,8 +487,12 @@ impl<'a, 'cfg: 'a> CompilationFiles<'a, 'cfg> {
 
         let info = bcx.target_data.info(unit.kind);
         let triple = bcx.target_data.short_name(&unit.kind);
-        let (file_types, unsupported) =
-            info.rustc_outputs(unit.mode, unit.target.kind(), triple)?;
+        let (file_types, unsupported) = info.rustc_outputs(
+            unit.mode,
+            unit.target.kind(),
+            triple,
+            unit.profile.split_debuginfo.as_deref(),
+        )?;
         if file_types.is_empty() {
             if !unsupported.is_empty() {
                 let unsupported_strs: Vec<_> = unsupported.iter().map(|ct| ct.as_str()).collect();

src/cargo/ops/cargo_clean.rs

@@ -174,7 +174,7 @@ pub fn clean(ws: &Workspace<'_>, opts: &CleanOptions<'_>) -> CargoResult<()> {
 
                     let (file_types, _unsupported) = target_data
                         .info(*compile_kind)
-                        .rustc_outputs(mode, target.kind(), triple)?;
+                        .rustc_outputs(mode, target.kind(), triple, None)?;
                     let (dir, uplift_dir) = match target.kind() {
                         TargetKind::ExampleBin | TargetKind::ExampleLib(..) => {
                             (layout.examples(), Some(layout.examples()))
@@ -203,6 +203,8 @@ pub fn clean(ws: &Workspace<'_>, opts: &CleanOptions<'_>) -> CargoResult<()> {
                         rm_rf_glob(&split_debuginfo_obj, config, &mut progress)?;
                         let split_debuginfo_dwo = dir_glob.join(format!("{}.*.dwo", crate_name));
                         rm_rf_glob(&split_debuginfo_dwo, config, &mut progress)?;
+                        let split_debuginfo_dwp = dir_glob.join(format!("{}.*.dwp", crate_name));
+                        rm_rf_glob(&split_debuginfo_dwp, config, &mut progress)?;
 
                         // Remove the uplifted copy.
                         if let Some(uplift_dir) = uplift_dir {