Add Rustfmt

.gitmodules

@@ -36,3 +36,6 @@
 [submodule "src/tools/clippy"]
 	path = src/tools/clippy
 	url = https://github.com/rust-lang-nursery/rust-clippy.git
+[submodule "src/tools/rustfmt"]
+	path = src/tools/rustfmt
+	url = [email protected]:rust-lang-nursery/rustfmt.git

src/Cargo.toml

@@ -18,6 +18,7 @@ members = [
   "tools/cargo",
   "tools/rustdoc",
   "tools/rls",
+  "tools/rustfmt",
   # FIXME(https://github.com/rust-lang/cargo/issues/4089): move these to exclude
   "tools/rls/test_data/borrow_error",
   "tools/rls/test_data/completion",
@@ -58,3 +59,9 @@ debug-assertions = false
 
 [patch.'https://github.com/rust-lang/cargo']
 cargo = { path = "tools/cargo" }
+
+[patch.'https://github.com/rust-lang-nursery/rustfmt']
+rustfmt-nightly = { path = "tools/rustfmt" }
+
+[patch.crates-io]
+rustfmt-nightly = { path = "tools/rustfmt" }

src/bootstrap/builder.rs

@@ -249,11 +249,11 @@ impl<'a> Builder<'a> {
                 tool::UnstableBookGen, tool::Tidy, tool::Linkchecker, tool::CargoTest,
                 tool::Compiletest, tool::RemoteTestServer, tool::RemoteTestClient,
                 tool::RustInstaller, tool::Cargo, tool::Rls, tool::Rustdoc, tool::Clippy,
-                native::Llvm),
+                native::Llvm, tool::Rustfmt),
             Kind::Test => describe!(check::Tidy, check::Bootstrap, check::DefaultCompiletest,
                 check::HostCompiletest, check::Crate, check::CrateLibrustc, check::Rustdoc,
                 check::Linkcheck, check::Cargotest, check::Cargo, check::Rls, check::Docs,
-                check::ErrorIndex, check::Distcheck),
+                check::ErrorIndex, check::Distcheck, check::Rustfmt),
             Kind::Bench => describe!(check::Crate, check::CrateLibrustc),
             Kind::Doc => describe!(doc::UnstableBook, doc::UnstableBookGen, doc::TheBook,
                 doc::Standalone, doc::Std, doc::Test, doc::Rustc, doc::ErrorIndex, doc::Nomicon,

src/bootstrap/check.rs

@@ -253,6 +253,47 @@ impl Step for Rls {
     }
 }
 
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub struct Rustfmt {
+    stage: u32,
+    host: Interned<String>,
+}
+
+impl Step for Rustfmt {
+    type Output = ();
+    const ONLY_HOSTS: bool = true;
+
+    fn should_run(run: ShouldRun) -> ShouldRun {
+        run.path("src/tools/rustfmt")
+    }
+
+    fn make_run(run: RunConfig) {
+        run.builder.ensure(Rustfmt {
+            stage: run.builder.top_stage,
+            host: run.target,
+        });
+    }
+
+    /// Runs `cargo test` for rustfmt.
+    fn run(self, builder: &Builder) {
+        let build = builder.build;
+        let stage = self.stage;
+        let host = self.host;
+        let compiler = builder.compiler(stage, host);
+
+        builder.ensure(tool::Rustfmt { compiler, target: self.host });
+        let mut cargo = builder.cargo(compiler, Mode::Tool, host, "test");
+        cargo.arg("--manifest-path").arg(build.src.join("src/tools/rustfmt/Cargo.toml"));
+
+        // Don't build tests dynamically, just a pain to work with
+        cargo.env("RUSTC_NO_PREFER_DYNAMIC", "1");
+
+        builder.add_rustc_lib_path(compiler, &mut cargo);
+
+        try_run(build, &mut cargo);
+    }
+}
+
 fn path_for_cargo(builder: &Builder, compiler: Compiler) -> OsString {
     // Configure PATH to find the right rustc. NB. we have to use PATH
     // and not RUSTC because the Cargo test suite has tests that will

src/bootstrap/tool.rs

@@ -431,6 +431,40 @@ impl Step for Rls {
     }
 }
 
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+pub struct Rustfmt {
+    pub compiler: Compiler,
+    pub target: Interned<String>,
+}
+
+impl Step for Rustfmt {
+    type Output = PathBuf;
+    const DEFAULT: bool = true;
+    const ONLY_HOSTS: bool = true;
+
+    fn should_run(run: ShouldRun) -> ShouldRun {
+        let builder = run.builder;
+        run.path("src/tools/rustfmt").default_condition(builder.build.config.extended)
+    }
+
+    fn make_run(run: RunConfig) {
+        run.builder.ensure(Rustfmt {
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.build.build),
+            target: run.target,
+        });
+    }
+
+    fn run(self, builder: &Builder) -> PathBuf {
+        builder.ensure(ToolBuild {
+            compiler: self.compiler,
+            target: self.target,
+            tool: "rustfmt",
+            mode: Mode::Librustc,
+            path: "src/tools/rustfmt",
+        })
+    }
+}
+
 impl<'a> Builder<'a> {
     /// Get a `Command` which is ready to run `tool` in `stage` built for
     /// `host`.

src/tools/tidy/src/lib.rs

@@ -64,6 +64,7 @@ fn filter_dirs(path: &Path) -> bool {
         "src/tools/rls",
         "src/tools/clippy",
         "src/tools/rust-installer",
+        "src/tools/rustfmt",
     ];
     skip.iter().any(|p| path.ends_with(p))
 }