Auto merge of #83846 - torhovland:issue-10971, r=davidtwco

Added the --temps-dir option

Fixes #10971.

The new `--temps-dir` option puts intermediate files in a user-specified directory. This provides a fix for the issue where parallel invocations of rustc would overwrite each other's intermediate files.

No files are kept in the intermediate directory unless `-C save-temps=yes`.

If additional files are specifically requested using `--emit asm,llvm-bc,llvm-ir,obj,metadata,link,dep-info,mir`, these will be put in the output directory rather than the intermediate directory.

This is a backward-compatible change, i.e. if `--temps-dir` is not specified, the behavior is the same as before.

compiler/rustc_interface/src/interface.rs

@@ -36,6 +36,7 @@ pub struct Compiler {
     pub(crate) input_path: Option<PathBuf>,
     pub(crate) output_dir: Option<PathBuf>,
     pub(crate) output_file: Option<PathBuf>,
+    pub(crate) temps_dir: Option<PathBuf>,
     pub(crate) register_lints: Option<Box<dyn Fn(&Session, &mut LintStore) + Send + Sync>>,
     pub(crate) override_queries:
         Option<fn(&Session, &mut ty::query::Providers, &mut ty::query::ExternProviders)>,
@@ -57,6 +58,9 @@ impl Compiler {
     pub fn output_file(&self) -> &Option<PathBuf> {
         &self.output_file
     }
+    pub fn temps_dir(&self) -> &Option<PathBuf> {
+        &self.temps_dir
+    }
     pub fn register_lints(&self) -> &Option<Box<dyn Fn(&Session, &mut LintStore) + Send + Sync>> {
         &self.register_lints
     }
@@ -65,7 +69,14 @@ impl Compiler {
         sess: &Session,
         attrs: &[ast::Attribute],
     ) -> OutputFilenames {
-        util::build_output_filenames(&self.input, &self.output_dir, &self.output_file, attrs, sess)
+        util::build_output_filenames(
+            &self.input,
+            &self.output_dir,
+            &self.output_file,
+            &self.temps_dir,
+            attrs,
+            sess,
+        )
     }
 }
 
@@ -186,6 +197,8 @@ pub fn create_compiler_and_run<R>(config: Config, f: impl FnOnce(&Compiler) -> R
         );
     }
 
+    let temps_dir = sess.opts.debugging_opts.temps_dir.as_ref().map(|o| PathBuf::from(&o));
+
     let compiler = Compiler {
         sess,
         codegen_backend,
@@ -193,6 +206,7 @@ pub fn create_compiler_and_run<R>(config: Config, f: impl FnOnce(&Compiler) -> R
         input_path: config.input_path,
         output_dir: config.output_dir,
         output_file: config.output_file,
+        temps_dir,
         register_lints: config.register_lints,
         override_queries: config.override_queries,
     };

compiler/rustc_interface/src/passes.rs

@@ -692,6 +692,7 @@ pub fn prepare_outputs(
         &compiler.input,
         &compiler.output_dir,
         &compiler.output_file,
+        &compiler.temps_dir,
         &krate.attrs,
         sess,
     );
@@ -722,6 +723,13 @@ pub fn prepare_outputs(
         }
     }
 
+    if let Some(ref dir) = compiler.temps_dir {
+        if fs::create_dir_all(dir).is_err() {
+            sess.err("failed to find or create the directory specified by `--temps-dir`");
+            return Err(ErrorReported);
+        }
+    }
+
     write_out_deps(sess, boxed_resolver, &outputs, &output_paths);
 
     let only_dep_info = sess.opts.output_types.contains_key(&OutputType::DepInfo)

compiler/rustc_interface/src/tests.rs

@@ -685,6 +685,7 @@ fn test_debugging_options_tracking_hash() {
     untracked!(span_debug, true);
     untracked!(span_free_formats, true);
     untracked!(strip, Strip::Debuginfo);
+    untracked!(temps_dir, Some(String::from("abc")));
     untracked!(terminal_width, Some(80));
     untracked!(threads, 99);
     untracked!(time, true);

compiler/rustc_interface/src/util.rs

@@ -604,6 +604,7 @@ pub fn build_output_filenames(
     input: &Input,
     odir: &Option<PathBuf>,
     ofile: &Option<PathBuf>,
+    temps_dir: &Option<PathBuf>,
     attrs: &[ast::Attribute],
     sess: &Session,
 ) -> OutputFilenames {
@@ -626,6 +627,7 @@ pub fn build_output_filenames(
                 dirpath,
                 stem,
                 None,
+                temps_dir.clone(),
                 sess.opts.cg.extra_filename.clone(),
                 sess.opts.output_types.clone(),
             )
@@ -654,6 +656,7 @@ pub fn build_output_filenames(
                 out_file.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),
                 out_file.file_stem().unwrap_or_default().to_str().unwrap().to_string(),
                 ofile,
+                temps_dir.clone(),
                 sess.opts.cg.extra_filename.clone(),
                 sess.opts.output_types.clone(),
             )