Enable building clippy in CI

src/bootstrap/check.rs

@@ -358,6 +358,7 @@ impl Step for Miri {
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct Clippy {
+    stage: u32,
     host: Interned<String>,
 }
 
@@ -372,24 +373,28 @@ impl Step for Clippy {
 
     fn make_run(run: RunConfig) {
         run.builder.ensure(Clippy {
+            stage: run.builder.top_stage,
             host: run.target,
         });
     }
 
     /// Runs `cargo test` for clippy.
     fn run(self, builder: &Builder) {
         let build = builder.build;
+        let stage = self.stage;
         let host = self.host;
-        let compiler = builder.compiler(1, host);
+        let compiler = builder.compiler(stage, host);
 
-        let _clippy = builder.ensure(tool::Clippy { compiler, target: self.host });
+        let clippy = builder.ensure(tool::Clippy { compiler, target: self.host });
         let mut cargo = builder.cargo(compiler, Mode::Tool, host, "test");
         cargo.arg("--manifest-path").arg(build.src.join("src/tools/clippy/Cargo.toml"));
 
         // Don't build tests dynamically, just a pain to work with
         cargo.env("RUSTC_NO_PREFER_DYNAMIC", "1");
         // clippy tests need to know about the stage sysroot
         cargo.env("SYSROOT", builder.sysroot(compiler));
+        // clippy tests need to find the driver
+        cargo.env("CLIPPY_DRIVER_PATH", clippy);
 
         builder.add_rustc_lib_path(compiler, &mut cargo);
 

src/bootstrap/tool.rs

@@ -387,7 +387,7 @@ pub struct Clippy {
 
 impl Step for Clippy {
     type Output = PathBuf;
-    const DEFAULT: bool = false;
+    const DEFAULT: bool = true;
     const ONLY_HOSTS: bool = true;
 
     fn should_run(run: ShouldRun) -> ShouldRun {
@@ -411,7 +411,7 @@ impl Step for Clippy {
         builder.ensure(ToolBuild {
             compiler: self.compiler,
             target: self.target,
-            tool: "clippy",
+            tool: "clippy-driver",
             mode: Mode::Librustc,
             path: "src/tools/clippy",
             expectation: builder.build.config.toolstate.clippy.passes(ToolState::Compiling),

src/tools/toolstate.toml

@@ -3,7 +3,7 @@
 #
 # There are three states a tool can be in:
 # 1. Broken: The tool doesn't build
-# 2. Building: The tool builds but its tests are failing
+# 2. Compiling: The tool builds but its tests are failing
 # 3. Testing: The tool builds and its tests are passing
 #
 # In the future there will be further states like "Distributing", which
@@ -26,7 +26,7 @@
 miri = "Broken"
 
 # ping @Manishearth @llogiq @mcarton @oli-obk
-clippy = "Broken"
+clippy = "Compiling"
 
 # ping @nrc
 rls = "Testing"