Rollup merge of rust-lang#83846 - torhovland:issue-10971, r=davidtwco

Added the --temps-dir option

Fixes rust-lang#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_driver/src/lib.rs

@@ -216,13 +216,15 @@ fn run_compiler(
 
     let cfg = interface::parse_cfgspecs(matches.opt_strs("cfg"));
     let (odir, ofile) = make_output(&matches);
+    let temps_dir = make_temps_dir(&matches);
     let mut config = interface::Config {
         opts: sopts,
         crate_cfg: cfg,
         input: Input::File(PathBuf::new()),
         input_path: None,
         output_file: ofile,
         output_dir: odir,
+        temps_dir,
         file_loader,
         diagnostic_output,
         stderr: None,
@@ -268,6 +270,7 @@ fn run_compiler(
                         None,
                         &compiler.output_dir(),
                         &compiler.output_file(),
+                        &compiler.temps_dir(),
                     );
 
                     if should_stop == Compilation::Stop {
@@ -296,6 +299,7 @@ fn run_compiler(
             Some(compiler.input()),
             compiler.output_dir(),
             compiler.output_file(),
+            compiler.temps_dir(),
         )
         .and_then(|| {
             RustcDefaultCalls::list_metadata(
@@ -461,6 +465,11 @@ fn make_output(matches: &getopts::Matches) -> (Option<PathBuf>, Option<PathBuf>)
     (odir, ofile)
 }
 
+// Extract temporary directory from matches.
+fn make_temps_dir(matches: &getopts::Matches) -> Option<PathBuf> {
+    matches.opt_str("temps-dir").map(|o| PathBuf::from(&o))
+}
+
 // Extract input (string or file and optional path) from matches.
 fn make_input(
     error_format: ErrorOutputType,
@@ -650,6 +659,7 @@ impl RustcDefaultCalls {
         input: Option<&Input>,
         odir: &Option<PathBuf>,
         ofile: &Option<PathBuf>,
+        temps_dir: &Option<PathBuf>,
     ) -> Compilation {
         use rustc_session::config::PrintRequest::*;
         // PrintRequest::NativeStaticLibs is special - printed during linking
@@ -691,7 +701,7 @@ impl RustcDefaultCalls {
                     });
                     let attrs = attrs.as_ref().unwrap();
                     let t_outputs = rustc_interface::util::build_output_filenames(
-                        input, odir, ofile, attrs, sess,
+                        input, odir, ofile, temps_dir, attrs, sess,
                     );
                     let id = rustc_session::output::find_crate_name(sess, attrs, input);
                     if *req == PrintRequest::CrateName {

compiler/rustc_interface/src/interface.rs

@@ -35,6 +35,7 @@ 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::Providers)>,
@@ -56,6 +57,9 @@ 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
     }
@@ -68,6 +72,7 @@ impl Compiler {
             &self.input,
             &self.output_dir,
             &self.output_file,
+            &self.temps_dir,
             &attrs,
             &sess,
         )
@@ -134,6 +139,7 @@ pub struct Config {
     pub input_path: Option<PathBuf>,
     pub output_dir: Option<PathBuf>,
     pub output_file: Option<PathBuf>,
+    pub temps_dir: Option<PathBuf>,
     pub file_loader: Option<Box<dyn FileLoader + Send + Sync>>,
     pub diagnostic_output: DiagnosticOutput,
 
@@ -195,6 +201,7 @@ 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: config.temps_dir,
         register_lints: config.register_lints,
         override_queries: config.override_queries,
     };

compiler/rustc_interface/src/passes.rs

@@ -709,6 +709,7 @@ pub fn prepare_outputs(
         &compiler.input,
         &compiler.output_dir,
         &compiler.output_file,
+        &compiler.temps_dir,
         &krate.attrs,
         sess,
     );
@@ -739,6 +740,13 @@ 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/util.rs

@@ -636,6 +636,7 @@ pub fn build_output_filenames(
     input: &Input,
     odir: &Option<PathBuf>,
     ofile: &Option<PathBuf>,
+    temps_dir: &Option<PathBuf>,
     attrs: &[ast::Attribute],
     sess: &Session,
 ) -> OutputFilenames {
@@ -658,6 +659,7 @@ pub fn build_output_filenames(
                 dirpath,
                 stem,
                 None,
+                temps_dir.clone(),
                 sess.opts.cg.extra_filename.clone(),
                 sess.opts.output_types.clone(),
             )
@@ -686,6 +688,7 @@ 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(),
             )

compiler/rustc_session/src/config.rs

@@ -563,6 +563,7 @@ pub struct OutputFilenames {
     pub out_directory: PathBuf,
     filestem: String,
     pub single_output_file: Option<PathBuf>,
+    pub temps_directory: Option<PathBuf>,
     pub outputs: OutputTypes,
 }
 
@@ -577,12 +578,14 @@ impl OutputFilenames {
         out_directory: PathBuf,
         out_filestem: String,
         single_output_file: Option<PathBuf>,
+        temps_directory: Option<PathBuf>,
         extra: String,
         outputs: OutputTypes,
     ) -> Self {
         OutputFilenames {
             out_directory,
             single_output_file,
+            temps_directory,
             outputs,
             filestem: format!("{}{}", out_filestem, extra),
         }
@@ -593,7 +596,14 @@ impl OutputFilenames {
             .get(&flavor)
             .and_then(|p| p.to_owned())
             .or_else(|| self.single_output_file.clone())
-            .unwrap_or_else(|| self.temp_path(flavor, None))
+            .unwrap_or_else(|| self.output_path(flavor))
+    }
+
+    /// Gets the output path where a compilation artifact of the given type
+    /// should be placed on disk.
+    pub fn output_path(&self, flavor: OutputType) -> PathBuf {
+        let extension = flavor.extension();
+        self.with_directory_and_extension(&self.out_directory, &extension)
     }
 
     /// Gets the path where a compilation artifact of the given type for the
@@ -628,11 +638,17 @@ impl OutputFilenames {
             extension.push_str(ext);
         }
 
-        self.with_extension(&extension)
+        let temps_directory = self.temps_directory.as_ref().unwrap_or(&self.out_directory);
+
+        self.with_directory_and_extension(&temps_directory, &extension)
     }
 
     pub fn with_extension(&self, extension: &str) -> PathBuf {
-        let mut path = self.out_directory.join(&self.filestem);
+        self.with_directory_and_extension(&self.out_directory, extension)
+    }
+
+    fn with_directory_and_extension(&self, directory: &PathBuf, extension: &str) -> PathBuf {
+        let mut path = directory.join(&self.filestem);
         path.set_extension(extension);
         path
     }
@@ -1072,6 +1088,7 @@ pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
              in <dir>",
             "DIR",
         ),
+        opt::opt_s("", "temps-dir", "Write temporary output files to <dir>", "DIR"),
         opt::opt_s(
             "",
             "explain",

src/doc/rustc/src/command-line-arguments.md

@@ -194,6 +194,15 @@ This flag controls the output filename.
 The outputted crate will be written to this directory. This flag is ignored if
 the [`-o` flag](#option-o-output) is used.
 
+<a id="option-temps-dir"></a>
+## `--temps-dir`: directory to write the intermediate files in
+
+Intermediate files will be written to this directory. If not set, the output
+directory is used. This option is useful if you are running more than one
+instance of `rustc` (e.g. with different `--crate-type` settings), and you
+need to make sure they are not overwriting each other's intermediate files.
+No files are kept unless `-C save-temps=yes` is also set.
+
 <a id="option-explain"></a>
 ## `--explain`: provide a detailed explanation of an error message
 

src/librustdoc/core.rs

@@ -259,6 +259,7 @@ crate fn create_config(
         input_path: cpath,
         output_file: None,
         output_dir: None,
+        temps_dir: None,
         file_loader: None,
         diagnostic_output: DiagnosticOutput::Default,
         stderr: None,

src/librustdoc/doctest.rs

@@ -92,6 +92,7 @@ crate fn run(options: Options) -> Result<(), ErrorReported> {
         input_path: None,
         output_file: None,
         output_dir: None,
+        temps_dir: None,
         file_loader: None,
         diagnostic_output: DiagnosticOutput::Default,
         stderr: None,

src/test/run-make-fulldeps/issue-19371/foo.rs

@@ -53,6 +53,7 @@ fn compile(code: String, output: PathBuf, sysroot: PathBuf) {
         input_path: None,
         output_file: Some(output),
         output_dir: None,
+        temps_dir: None,
         file_loader: None,
         diagnostic_output: DiagnosticOutput::Default,
         stderr: None,

src/test/run-make/issue-10971-temps-dir/Makefile

@@ -0,0 +1,8 @@
+# Regression test for issue #10971
+# Running two invocations in parallel would overwrite each other's temp files.
+
+all:
+	touch $(TMPDIR)/lib.rs
+
+	$(RUSTC) --crate-type=lib --temps-dir=$(TMPDIR)/temp1 --out-dir=$(TMPDIR) $(TMPDIR)/lib.rs \
+		& $(RUSTC) --crate-type=cdylib --temps-dir=$(TMPDIR)/temp2 --out-dir=$(TMPDIR) $(TMPDIR)/lib.rs