let ToolBuild to handle compiler tool stages automatically

Signed-off-by: onur-ozkan <work@onurozkan.dev>

Author: onur-ozkan

src/bootstrap/src/core/build_steps/run.rs

@@ -126,7 +126,7 @@ impl Step for Miri {
         // This compiler runs on the host, we'll just use it for the target.
         let target_compiler = builder.compiler(stage, host);
         // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
-        // we'd have stageN/bin/rustc and stageN/bin/rustdoc be effectively different stage
+        // we'd have stageN/bin/rustc and stageN/bin/miri be effectively different stage
         // compilers, which isn't what we want. Rustdoc should be linked in the same way as the
         // rustc compiler it's paired with, so it must be built with the previous stage compiler.
         let host_compiler = builder.compiler(stage - 1, host);

src/bootstrap/src/core/build_steps/test.rs

@@ -522,23 +522,24 @@ impl Step for Miri {
 
         // This compiler runs on the host, we'll just use it for the target.
         let target_compiler = builder.compiler(stage, host);
-        // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
-        // we'd have stageN/bin/rustc and stageN/bin/rustdoc be effectively different stage
-        // compilers, which isn't what we want. Rustdoc should be linked in the same way as the
-        // rustc compiler it's paired with, so it must be built with the previous stage compiler.
-        let host_compiler = builder.compiler(stage - 1, host);
 
         // Build our tools.
-        let miri = builder.ensure(tool::Miri { compiler: host_compiler, target: host });
+        let miri = builder.ensure(tool::Miri { compiler: target_compiler, target: host });
         // the ui tests also assume cargo-miri has been built
-        builder.ensure(tool::CargoMiri { compiler: host_compiler, target: host });
+        builder.ensure(tool::CargoMiri { compiler: target_compiler, target: host });
 
         // We also need sysroots, for Miri and for the host (the latter for build scripts).
         // This is for the tests so everything is done with the target compiler.
         let miri_sysroot = Miri::build_miri_sysroot(builder, target_compiler, target);
         builder.ensure(compile::Std::new(target_compiler, host));
         let host_sysroot = builder.sysroot(target_compiler);
 
+        // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
+        // we'd have stageN/bin/rustc and stageN/bin/miri be effectively different stage
+        // compilers, which isn't what we want. Rustdoc should be linked in the same way as the
+        // rustc compiler it's paired with, so it must be built with the previous stage compiler.
+        let host_compiler = builder.compiler(stage - 1, host);
+
         // Miri has its own "target dir" for ui test dependencies. Make sure it gets cleared when
         // the sysroot gets rebuilt, to avoid "found possibly newer version of crate `std`" errors.
         if !builder.config.dry_run() {
@@ -1720,17 +1721,6 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
                 // If we're using `--stage 0`, we should provide the bootstrap cargo.
                 builder.initial_cargo.clone()
             } else {
-                // We need to properly build cargo using the suitable stage compiler.
-
-                let compiler = builder.download_rustc().then_some(compiler).unwrap_or_else(||
-                    // HACK: currently tool stages are off-by-one compared to compiler stages, i.e. if
-                    // you give `tool::Cargo` a stage 1 rustc, it will cause stage 2 rustc to be built
-                    // and produce a cargo built with stage 2 rustc. To fix this, we need to chop off
-                    // the compiler stage by 1 to align with expected `./x test run-make --stage N`
-                    // behavior, i.e. we need to pass `N - 1` compiler stage to cargo. See also Miri
-                    // which does a similar hack.
-                    builder.compiler(builder.top_stage - 1, compiler.host));
-
                 builder.ensure(tool::Cargo { compiler, target: compiler.host })
             };
 

src/bootstrap/src/core/builder/mod.rs

@@ -1395,8 +1395,8 @@ impl<'a> Builder<'a> {
         self.ensure(tool::Rustdoc { compiler })
     }
 
-    pub fn cargo_clippy_cmd(&self, run_compiler: Compiler) -> BootstrapCommand {
-        if run_compiler.stage == 0 {
+    pub fn cargo_clippy_cmd(&self, compiler: Compiler) -> BootstrapCommand {
+        if compiler.stage == 0 {
             let cargo_clippy = self
                 .config
                 .initial_cargo_clippy
@@ -1408,27 +1408,23 @@ impl<'a> Builder<'a> {
             return cmd;
         }
 
-        let build_compiler = self.compiler(run_compiler.stage - 1, self.build.build);
-        self.ensure(tool::Clippy { compiler: build_compiler, target: self.build.build });
-        let cargo_clippy =
-            self.ensure(tool::CargoClippy { compiler: build_compiler, target: self.build.build });
+        self.ensure(tool::Clippy { compiler, target: self.build.build });
+        let cargo_clippy = self.ensure(tool::CargoClippy { compiler, target: self.build.build });
         let mut dylib_path = helpers::dylib_path();
-        dylib_path.insert(0, self.sysroot(run_compiler).join("lib"));
+        dylib_path.insert(0, self.sysroot(compiler).join("lib"));
 
         let mut cmd = command(cargo_clippy);
         cmd.env(helpers::dylib_path_var(), env::join_paths(&dylib_path).unwrap());
         cmd.env("CARGO", &self.initial_cargo);
         cmd
     }
 
-    pub fn cargo_miri_cmd(&self, run_compiler: Compiler) -> BootstrapCommand {
-        assert!(run_compiler.stage > 0, "miri can not be invoked at stage 0");
-        let build_compiler = self.compiler(run_compiler.stage - 1, self.build.build);
+    pub fn cargo_miri_cmd(&self, compiler: Compiler) -> BootstrapCommand {
+        assert!(compiler.stage > 0, "miri can not be invoked at stage 0");
 
         // Prepare the tools
-        let miri = self.ensure(tool::Miri { compiler: build_compiler, target: self.build.build });
-        let cargo_miri =
-            self.ensure(tool::CargoMiri { compiler: build_compiler, target: self.build.build });
+        let miri = self.ensure(tool::Miri { compiler, target: self.build.build });
+        let cargo_miri = self.ensure(tool::CargoMiri { compiler, target: self.build.build });
         // Invoke cargo-miri, make sure it can find miri and cargo.
         let mut cmd = command(cargo_miri);
         cmd.env("MIRI", &miri);
@@ -1441,7 +1437,7 @@ impl<'a> Builder<'a> {
         // `add_rustc_lib_path` as that's a NOP on Windows but we do need these libraries added to
         // the PATH due to the stage mismatch.
         // Also see https://github.com/rust-lang/rust/pull/123192#issuecomment-2028901503.
-        add_dylib_path(self.rustc_lib_paths(run_compiler), &mut cmd);
+        add_dylib_path(self.rustc_lib_paths(compiler), &mut cmd);
         cmd
     }