stabilize stage management for rustc tools, especially on cargo

src/bootstrap/src/core/build_steps/check.rs

@@ -57,7 +57,7 @@ impl Step for Std {
         builder.require_submodule("library/stdarch", None);
 
         let target = self.target;
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.build, false);
 
         let mut cargo = builder::Cargo::new(
             builder,
@@ -192,7 +192,7 @@ impl Step for Rustc {
     /// the `compiler` targeting the `target` architecture. The artifacts
     /// created will also be linked into the sysroot directory.
     fn run(self, builder: &Builder<'_>) {
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.build, false);
         let target = self.target;
 
         if compiler.stage != 0 {
@@ -274,7 +274,7 @@ impl Step for CodegenBackend {
             return;
         }
 
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.build, false);
         let target = self.target;
         let backend = self.backend;
 
@@ -329,7 +329,7 @@ impl Step for RustAnalyzer {
     }
 
     fn run(self, builder: &Builder<'_>) {
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.build, true);
         let target = self.target;
 
         builder.ensure(Rustc::new(target, builder));
@@ -411,7 +411,7 @@ fn run_tool_check_step(
     path: &str,
 ) {
     let display_name = path.rsplit('/').next().unwrap();
-    let compiler = builder.compiler(builder.top_stage, builder.config.build);
+    let compiler = builder.compiler(builder.top_stage, builder.config.build, true);
 
     builder.ensure(Rustc::new(target, builder));
 

src/bootstrap/src/core/build_steps/clean.rs

@@ -60,7 +60,7 @@ macro_rules! clean_crate_tree {
 
             fn make_run(run: RunConfig<'_>) {
                 let builder = run.builder;
-                let compiler = builder.compiler(builder.top_stage, run.target);
+                let compiler = builder.compiler(builder.top_stage, run.target, false);
                 builder.ensure(Self { crates: run.cargo_crates_in_set(), compiler });
             }
 

src/bootstrap/src/core/build_steps/clippy.rs

@@ -144,7 +144,7 @@ impl Step for Std {
         builder.require_submodule("library/stdarch", None);
 
         let target = self.target;
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.build, false);
 
         let mut cargo = builder::Cargo::new(
             builder,
@@ -204,7 +204,7 @@ impl Step for Rustc {
     /// This will lint the compiler for a particular stage of the build using
     /// the `compiler` targeting the `target` architecture.
     fn run(self, builder: &Builder<'_>) {
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.build, false);
         let target = self.target;
 
         if compiler.stage != 0 {
@@ -254,7 +254,7 @@ impl Step for Rustc {
 
 macro_rules! lint_any {
     ($(
-        $name:ident, $path:expr, $readable_name:expr
+        $name:ident, $path:expr, $readable_name:expr, $mode:expr
         $(,lint_by_default = $lint_by_default:expr)*
         ;
     )+) => {
@@ -283,15 +283,15 @@ macro_rules! lint_any {
             }
 
             fn run(self, builder: &Builder<'_>) -> Self::Output {
-                let compiler = builder.compiler(builder.top_stage, builder.config.build);
+                let compiler = builder.compiler(builder.top_stage, builder.config.build, builder.top_stage > 0 && $mode == Mode::ToolRustc);
                 let target = self.target;
 
                 builder.ensure(check::Rustc::new(target, builder).build_kind(Some(Kind::Check)));
 
                 let cargo = prepare_tool_cargo(
                     builder,
                     compiler,
-                    Mode::ToolRustc,
+                    $mode,
                     target,
                     Kind::Clippy,
                     $path,
@@ -301,15 +301,15 @@ macro_rules! lint_any {
 
                 let _guard = builder.msg_tool(
                     Kind::Clippy,
-                    Mode::ToolRustc,
+                    $mode,
                     $readable_name,
                     compiler.stage,
                     &compiler.host,
                     &target,
                 );
 
                 let stringified_name = stringify!($name).to_lowercase();
-                let stamp = BuildStamp::new(&builder.cargo_out(compiler, Mode::ToolRustc, target))
+                let stamp = BuildStamp::new(&builder.cargo_out(compiler, $mode, target))
                     .with_prefix(&format!("{}-check", stringified_name));
 
                 run_cargo(
@@ -328,31 +328,31 @@ macro_rules! lint_any {
 }
 
 lint_any!(
-    Bootstrap, "src/bootstrap", "bootstrap";
-    BuildHelper, "src/build_helper", "build_helper";
-    BuildManifest, "src/tools/build-manifest", "build-manifest";
-    CargoMiri, "src/tools/miri/cargo-miri", "cargo-miri";
-    Clippy, "src/tools/clippy", "clippy";
-    CollectLicenseMetadata, "src/tools/collect-license-metadata", "collect-license-metadata";
-    CodegenGcc, "compiler/rustc_codegen_gcc", "rustc-codegen-gcc";
-    Compiletest, "src/tools/compiletest", "compiletest";
-    CoverageDump, "src/tools/coverage-dump", "coverage-dump";
-    Jsondocck, "src/tools/jsondocck", "jsondocck";
-    Jsondoclint, "src/tools/jsondoclint", "jsondoclint";
-    LintDocs, "src/tools/lint-docs", "lint-docs";
-    LlvmBitcodeLinker, "src/tools/llvm-bitcode-linker", "llvm-bitcode-linker";
-    Miri, "src/tools/miri", "miri";
-    MiroptTestTools, "src/tools/miropt-test-tools", "miropt-test-tools";
-    OptDist, "src/tools/opt-dist", "opt-dist";
-    RemoteTestClient, "src/tools/remote-test-client", "remote-test-client";
-    RemoteTestServer, "src/tools/remote-test-server", "remote-test-server";
-    Rls, "src/tools/rls", "rls";
-    RustAnalyzer, "src/tools/rust-analyzer", "rust-analyzer";
-    Rustdoc, "src/librustdoc", "clippy";
-    Rustfmt, "src/tools/rustfmt", "rustfmt";
-    RustInstaller, "src/tools/rust-installer", "rust-installer";
-    Tidy, "src/tools/tidy", "tidy";
-    TestFloatParse, "src/etc/test-float-parse", "test-float-parse";
+    Bootstrap, "src/bootstrap", "bootstrap", Mode::ToolBootstrap;
+    BuildHelper, "src/build_helper", "build_helper", Mode::ToolBootstrap;
+    BuildManifest, "src/tools/build-manifest", "build-manifest", Mode::ToolBootstrap;
+    CargoMiri, "src/tools/miri/cargo-miri", "cargo-miri", Mode::ToolRustc;
+    Clippy, "src/tools/clippy", "clippy", Mode::ToolRustc;
+    CollectLicenseMetadata, "src/tools/collect-license-metadata", "collect-license-metadata", Mode::ToolBootstrap;
+    CodegenGcc, "compiler/rustc_codegen_gcc", "rustc-codegen-gcc", Mode::ToolRustc;
+    Compiletest, "src/tools/compiletest", "compiletest", Mode::ToolBootstrap;
+    CoverageDump, "src/tools/coverage-dump", "coverage-dump", Mode::ToolBootstrap;
+    Jsondocck, "src/tools/jsondocck", "jsondocck", Mode::ToolBootstrap;
+    Jsondoclint, "src/tools/jsondoclint", "jsondoclint", Mode::ToolBootstrap;
+    LintDocs, "src/tools/lint-docs", "lint-docs", Mode::ToolBootstrap;
+    LlvmBitcodeLinker, "src/tools/llvm-bitcode-linker", "llvm-bitcode-linker", Mode::ToolRustc;
+    Miri, "src/tools/miri", "miri", Mode::ToolRustc;
+    MiroptTestTools, "src/tools/miropt-test-tools", "miropt-test-tools", Mode::ToolRustc;
+    OptDist, "src/tools/opt-dist", "opt-dist", Mode::ToolBootstrap;
+    RemoteTestClient, "src/tools/remote-test-client", "remote-test-client", Mode::ToolBootstrap;
+    RemoteTestServer, "src/tools/remote-test-server", "remote-test-server", Mode::ToolBootstrap;
+    Rls, "src/tools/rls", "rls", Mode::ToolBootstrap;
+    RustAnalyzer, "src/tools/rust-analyzer", "rust-analyzer", Mode::ToolRustc;
+    Rustdoc, "src/librustdoc", "clippy", Mode::ToolRustc;
+    Rustfmt, "src/tools/rustfmt", "rustfmt", Mode::ToolRustc;
+    RustInstaller, "src/tools/rust-installer", "rust-installer", Mode::ToolBootstrap;
+    Tidy, "src/tools/tidy", "tidy", Mode::ToolBootstrap;
+    TestFloatParse, "src/etc/test-float-parse", "test-float-parse", Mode::ToolStd;
 );
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]

src/bootstrap/src/core/build_steps/compile.rs

@@ -121,7 +121,7 @@ impl Step for Std {
         trace!(force_recompile);
 
         run.builder.ensure(Std {
-            compiler: run.builder.compiler(run.builder.top_stage, run.build_triple()),
+            compiler: run.builder.compiler(run.builder.top_stage, run.build_triple(), false),
             target: run.target,
             crates,
             force_recompile,
@@ -189,7 +189,7 @@ impl Step for Std {
 
         let mut target_deps = builder.ensure(StartupObjects { compiler, target });
 
-        let compiler_to_use = builder.compiler_for(compiler.stage, compiler.host, target);
+        let compiler_to_use = builder.compiler_for(compiler.stage, compiler.host, target, false);
         trace!(?compiler_to_use);
 
         if compiler_to_use != compiler {
@@ -310,7 +310,7 @@ impl Step for Std {
 
         builder.ensure(StdLink::from_std(
             self,
-            builder.compiler(compiler.stage, builder.config.build),
+            builder.compiler(compiler.stage, builder.config.build, false),
         ));
     }
 }
@@ -870,7 +870,7 @@ impl Step for StartupObjects {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(StartupObjects {
-            compiler: run.builder.compiler(run.builder.top_stage, run.build_triple()),
+            compiler: run.builder.compiler(run.builder.top_stage, run.build_triple(), false),
             target: run.target,
         });
     }
@@ -946,11 +946,18 @@ fn cp_rustc_component_to_ci_sysroot(builder: &Builder<'_>, sysroot: &Path, conte
     }
 }
 
+/// Low-level implementation of the compiler's compilation process.
+///
+/// DO NOT `pub` the fields of this type and AVOID using it anywhere
+/// unless it's in the `Assemble` step.
+///
+/// If you want to build a compiler for a specific stage and target, use
+/// `Builder::compiler` instead.
 #[derive(Debug, PartialOrd, Ord, Clone, PartialEq, Eq, Hash)]
 pub struct Rustc {
-    pub target: TargetSelection,
+    target: TargetSelection,
     /// The **previous** compiler used to compile this compiler.
-    pub compiler: Compiler,
+    compiler: Compiler,
     /// Whether to build a subset of crates, rather than the whole compiler.
     ///
     /// This should only be requested by the user, not used within bootstrap itself.
@@ -960,6 +967,9 @@ pub struct Rustc {
 }
 
 impl Rustc {
+    /// Serves as a helpful util for unit tests and should NEVER exist
+    /// for non-test environment.
+    #[cfg(test)]
     pub fn new(compiler: Compiler, target: TargetSelection) -> Self {
         Self { target, compiler, crates: Default::default() }
     }
@@ -993,7 +1003,7 @@ impl Step for Rustc {
     fn make_run(run: RunConfig<'_>) {
         let crates = run.cargo_crates_in_set();
         run.builder.ensure(Rustc {
-            compiler: run.builder.compiler(run.builder.top_stage, run.build_triple()),
+            compiler: run.builder.compiler(run.builder.top_stage, run.build_triple(), false),
             target: run.target,
             crates,
         });
@@ -1043,9 +1053,10 @@ impl Step for Rustc {
             return compiler.stage;
         }
 
-        let compiler_to_use = builder.compiler_for(compiler.stage, compiler.host, target);
+        let compiler_to_use = builder.compiler_for(compiler.stage, compiler.host, target, false);
         if compiler_to_use != compiler {
-            builder.ensure(Rustc::new(compiler_to_use, target));
+            let _ = builder.compiler(compiler_to_use.stage, target, false);
+
             let msg = if compiler_to_use.host == target {
                 format!(
                     "Uplifting rustc (stage{} -> stage{})",
@@ -1068,7 +1079,7 @@ impl Step for Rustc {
 
         // Ensure that build scripts and proc macros have a std / libproc_macro to link against.
         builder.ensure(Std::new(
-            builder.compiler(self.compiler.stage, builder.config.build),
+            builder.compiler(self.compiler.stage, builder.config.build, false),
             builder.config.build,
         ));
 
@@ -1134,7 +1145,7 @@ impl Step for Rustc {
 
         builder.ensure(RustcLink::from_rustc(
             self,
-            builder.compiler(compiler.stage, builder.config.build),
+            builder.compiler(compiler.stage, builder.config.build, false),
         ));
 
         compiler.stage
@@ -1550,7 +1561,7 @@ impl Step for CodegenBackend {
 
             run.builder.ensure(CodegenBackend {
                 target: run.target,
-                compiler: run.builder.compiler(run.builder.top_stage, run.build_triple()),
+                compiler: run.builder.compiler(run.builder.top_stage, run.build_triple(), false),
                 backend: backend.clone(),
             });
         }
@@ -1574,7 +1585,7 @@ impl Step for CodegenBackend {
         let target = self.target;
         let backend = self.backend;
 
-        builder.ensure(Rustc::new(compiler, target));
+        let _ = builder.compiler(compiler.stage, target, false);
 
         if builder.config.keep_stage.contains(&compiler.stage) {
             trace!("`keep-stage` requested");
@@ -1587,7 +1598,7 @@ impl Step for CodegenBackend {
             return;
         }
 
-        let compiler_to_use = builder.compiler_for(compiler.stage, compiler.host, target);
+        let compiler_to_use = builder.compiler_for(compiler.stage, compiler.host, target, false);
         if compiler_to_use != compiler {
             builder.ensure(CodegenBackend { compiler: compiler_to_use, target, backend });
             return;
@@ -1896,7 +1907,7 @@ impl Step for Assemble {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(Assemble {
-            target_compiler: run.builder.compiler(run.builder.top_stage + 1, run.target),
+            target_compiler: run.builder.compiler(run.builder.top_stage + 1, run.target, false),
         });
     }
 
@@ -1974,7 +1985,7 @@ impl Step for Assemble {
             }
         }
 
-        let maybe_install_llvm_bitcode_linker = |compiler| {
+        let maybe_install_llvm_bitcode_linker = |compiler: Compiler| {
             if builder.config.llvm_bitcode_linker_enabled {
                 trace!("llvm-bitcode-linker enabled, installing");
                 let src_path = builder.ensure(crate::core::build_steps::tool::LlvmBitcodeLinker {
@@ -2025,7 +2036,8 @@ impl Step for Assemble {
             target_compiler.stage - 1,
             builder.config.build,
         );
-        let mut build_compiler = builder.compiler(target_compiler.stage - 1, builder.config.build);
+        let mut build_compiler =
+            builder.compiler(target_compiler.stage - 1, builder.config.build, false);
 
         // Build enzyme
         if builder.config.llvm_enzyme {
@@ -2052,7 +2064,11 @@ impl Step for Assemble {
             "target_compiler.host" = ?target_compiler.host,
             "building compiler libraries to link to"
         );
-        let actual_stage = builder.ensure(Rustc::new(build_compiler, target_compiler.host));
+        let actual_stage = builder.ensure(Rustc {
+            compiler: build_compiler,
+            target: target_compiler.host,
+            crates: vec![],
+        });
         // Current build_compiler.stage might be uplifted instead of being built; so update it
         // to not fail while linking the artifacts.
         debug!(
@@ -2182,7 +2198,11 @@ impl Step for Assemble {
             );
         }
 
-        maybe_install_llvm_bitcode_linker(build_compiler);
+        {
+            let mut compiler_for_rustc_tool = build_compiler;
+            compiler_for_rustc_tool.downgraded_from = Some(target_compiler.stage);
+            maybe_install_llvm_bitcode_linker(compiler_for_rustc_tool);
+        }
 
         // Ensure that `libLLVM.so` ends up in the newly build compiler directory,
         // so that it can be found when the newly built `rustc` is run.