Port codegen backends to RustcPrivateCompilers

rust-lang · Zalathar · Jul 16, 2025 · Jul 21, 2025 · Jun 18, 2025 · Jul 22, 2025
commit efbaa77c41226f82df9563f6dd28b8224c4b2b75
diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs
@@ -19,7 +19,7 @@ use serde_derive::Deserialize;
 use tracing::{instrument, span};
 
 use crate::core::build_steps::gcc::{Gcc, add_cg_gcc_cargo_flags};
-use crate::core::build_steps::tool::{SourceType, copy_lld_artifacts};
+use crate::core::build_steps::tool::{RustcPrivateCompilers, SourceType, copy_lld_artifacts};
 use crate::core::build_steps::{dist, llvm};
 use crate::core::builder;
 use crate::core::builder::{
@@ -1133,7 +1133,7 @@ impl Step for Rustc {
             cargo.env("RUSTC_BOLT_LINK_FLAGS", "1");
         }
 
-        let _guard = builder.msg_sysroot_tool(
+        let _guard = builder.msg_rustc_tool(
             Kind::Build,
             build_compiler.stage,
             format_args!("compiler artifacts{}", crate_description(&self.crates)),
@@ -1546,9 +1546,8 @@ impl Step for RustcLink {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct CodegenBackend {
-    pub target: TargetSelection,
-    pub compiler: Compiler,
-    pub backend: String,
+    compilers: RustcPrivateCompilers,
+    backend: String,
 }
 
 fn needs_codegen_config(run: &RunConfig<'_>) -> bool {
@@ -1612,8 +1611,11 @@ impl Step for CodegenBackend {
             }
 
             run.builder.ensure(CodegenBackend {
-                target: run.target,
-                compiler: run.builder.compiler(run.builder.top_stage, run.build_triple()),
+                compilers: RustcPrivateCompilers::new(
+                    run.builder,
+                    run.builder.top_stage,
+                    run.target,
+                ),
                 backend: backend.clone(),
             });
         }
@@ -1626,21 +1628,17 @@ impl Step for CodegenBackend {
             name = "CodegenBackend::run",
             skip_all,
             fields(
-                compiler = ?self.compiler,
-                target = ?self.target,
-                backend = ?self.target,
+                compilers = ?self.compilers,
+                backend = ?self.backend,
             ),
         ),
     )]
     fn run(self, builder: &Builder<'_>) {
-        let compiler = self.compiler;
-        let target = self.target;
         let backend = self.backend;
+        let target = self.compilers.target();
+        let build_compiler = self.compilers.build_compiler();
 
-        // FIXME: migrate to RustcPrivateCompilers
-        builder.ensure(Rustc::new(compiler, target));
-
-        if builder.config.keep_stage.contains(&compiler.stage) {
+        if builder.config.keep_stage.contains(&build_compiler.stage) {
             trace!("`keep-stage` requested");
             builder.info(
                 "WARNING: Using a potentially old codegen backend. \
@@ -1651,17 +1649,11 @@ impl Step for CodegenBackend {
             return;
         }
 
-        let compiler_to_use = builder.compiler_for(compiler.stage, compiler.host, target);
-        if compiler_to_use != compiler {
-            builder.ensure(CodegenBackend { compiler: compiler_to_use, target, backend });
-            return;
-        }
-
-        let out_dir = builder.cargo_out(compiler, Mode::Codegen, target);
+        let out_dir = builder.cargo_out(build_compiler, Mode::Codegen, target);
 
         let mut cargo = builder::Cargo::new(
             builder,
-            compiler,
+            build_compiler,
             Mode::Codegen,
             SourceType::InTree,
             target,
@@ -1682,7 +1674,13 @@ impl Step for CodegenBackend {
 
         let tmp_stamp = BuildStamp::new(&out_dir).with_prefix("tmp");
 
-        let _guard = builder.msg_build(compiler, format_args!("codegen backend {backend}"), target);
+        let _guard = builder.msg_rustc_tool(
+            Kind::Build,
+            build_compiler.stage,
+            format_args!("codegen backend {backend}"),
+            build_compiler.host,
+            target,
+        );
         let files = run_cargo(builder, cargo, vec![], &tmp_stamp, vec![], false, false);
         if builder.config.dry_run() {
             return;
@@ -1702,15 +1700,18 @@ impl Step for CodegenBackend {
                 f.display()
             );
         }
-        let stamp = build_stamp::codegen_backend_stamp(builder, compiler, target, &backend);
+        let stamp = build_stamp::codegen_backend_stamp(builder, build_compiler, target, &backend);
         let codegen_backend = codegen_backend.to_str().unwrap();
         t!(stamp.add_stamp(codegen_backend).write());
     }
 
     fn metadata(&self) -> Option<StepMetadata> {
         Some(
-            StepMetadata::build(&format!("rustc_codegen_{}", self.backend), self.target)
-                .built_by(self.compiler),
+            StepMetadata::build(
+                &format!("rustc_codegen_{}", self.backend),
+                self.compilers.target(),
+            )
+            .built_by(self.compilers.build_compiler()),
         )
     }
 }
@@ -2199,8 +2200,10 @@ impl Step for Assemble {
                 continue;
             }
             builder.ensure(CodegenBackend {
-                compiler: build_compiler,
-                target: target_compiler.host,
+                compilers: RustcPrivateCompilers::from_build_and_link_compiler(
+                    build_compiler,
+                    target_compiler,
+                ),
                 backend: backend.clone(),
             });
         }

diff --git a/src/bootstrap/src/core/build_steps/doc.rs b/src/bootstrap/src/core/build_steps/doc.rs
@@ -811,7 +811,7 @@ impl Step for Rustc {
         let compiler = builder.compiler(stage, builder.config.host_target);
         builder.std(compiler, builder.config.host_target);
 
-        let _guard = builder.msg_sysroot_tool(
+        let _guard = builder.msg_rustc_tool(
             Kind::Doc,
             stage,
             format!("compiler{}", crate_description(&self.crates)),

diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
@@ -600,7 +600,7 @@ impl Step for Miri {
         cargo.env("MIRI_TEST_TARGET", target.rustc_target_arg());
 
         {
-            let _guard = builder.msg_sysroot_tool(Kind::Test, stage, "miri", host, target);
+            let _guard = builder.msg_rustc_tool(Kind::Test, stage, "miri", host, target);
             let _time = helpers::timeit(builder);
             cargo.run(builder);
         }
@@ -616,7 +616,7 @@ impl Step for Miri {
             cargo.args(["tests/pass", "tests/panic"]);
 
             {
-                let _guard = builder.msg_sysroot_tool(
+                let _guard = builder.msg_rustc_tool(
                     Kind::Test,
                     stage,
                     "miri (mir-opt-level 4)",
@@ -693,7 +693,7 @@ impl Step for CargoMiri {
         // Finally, run everything.
         let mut cargo = BootstrapCommand::from(cargo);
         {
-            let _guard = builder.msg_sysroot_tool(Kind::Test, stage, "cargo-miri", host, target);
+            let _guard = builder.msg_rustc_tool(Kind::Test, stage, "cargo-miri", host, target);
             let _time = helpers::timeit(builder);
             cargo.run(builder);
         }
@@ -820,8 +820,7 @@ impl Step for Clippy {
         cargo.add_rustc_lib_path(builder);
         let cargo = prepare_cargo_test(cargo, &[], &[], host, builder);
 
-        let _guard =
-            builder.msg_sysroot_tool(Kind::Test, build_compiler.stage, "clippy", host, host);
+        let _guard = builder.msg_rustc_tool(Kind::Test, build_compiler.stage, "clippy", host, host);
 
         // Clippy reports errors if it blessed the outputs
         if cargo.allow_failure().run(builder) {
@@ -1088,7 +1087,7 @@ impl Step for RustdocGUI {
         }
 
         let _time = helpers::timeit(builder);
-        let _guard = builder.msg_sysroot_tool(
+        let _guard = builder.msg_rustc_tool(
             Kind::Test,
             self.compiler.stage,
             "rustdoc-gui",
@@ -2573,7 +2572,7 @@ fn run_cargo_test<'a>(
     let mut cargo = prepare_cargo_test(cargo, libtest_args, crates, target, builder);
     let _time = helpers::timeit(builder);
     let _group = description.into().and_then(|what| {
-        builder.msg_sysroot_tool(Kind::Test, compiler.stage, what, compiler.host, target)
+        builder.msg_rustc_tool(Kind::Test, compiler.stage, what, compiler.host, target)
     });
 
     #[cfg(feature = "build-metrics")]

diff --git a/src/bootstrap/src/core/build_steps/tool.rs b/src/bootstrap/src/core/build_steps/tool.rs
@@ -71,13 +71,9 @@ impl Builder<'_> {
     ) -> Option<gha::Group> {
         match mode {
             // depends on compiler stage, different to host compiler
-            Mode::ToolRustc => self.msg_sysroot_tool(
-                kind,
-                build_stage,
-                format_args!("tool {tool}"),
-                *host,
-                *target,
-            ),
+            Mode::ToolRustc => {
+                self.msg_rustc_tool(kind, build_stage, format_args!("tool {tool}"), *host, *target)
+            }
             // doesn't depend on compiler, same as host compiler
             _ => self.msg(kind, build_stage, format_args!("tool {tool}"), *host, *target),
         }
@@ -1327,6 +1323,10 @@ impl RustcPrivateCompilers {
         Self { build_compiler, link_compiler }
     }
 
+    pub fn from_build_and_link_compiler(build_compiler: Compiler, link_compiler: Compiler) -> Self {
+        Self { build_compiler, link_compiler }
+    }
+
     /// Create rustc tool compilers from the build compiler.
     pub fn from_build_compiler(
         builder: &Builder<'_>,

diff --git a/src/bootstrap/src/core/builder/tests.rs b/src/bootstrap/src/core/builder/tests.rs
@@ -731,9 +731,6 @@ mod snapshot {
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 0 <host> -> rustc_codegen_cranelift 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
-        [build] rustc 1 <host> -> std 1 <host>
-        [build] rustc 1 <host> -> rustc 2 <host>
-        [build] rustc 1 <host> -> rustc_codegen_cranelift 2 <host>
         [build] rustdoc 1 <host>
         "
         );

diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
@@ -1060,17 +1060,6 @@ impl Build {
         self.msg(Kind::Doc, compiler.stage, what, compiler.host, target.into())
     }
 
-    #[must_use = "Groups should not be dropped until the Step finishes running"]
-    #[track_caller]
-    fn msg_build(
-        &self,
-        compiler: Compiler,
-        what: impl Display,
-        target: impl Into<Option<TargetSelection>>,
-    ) -> Option<gha::Group> {
-        self.msg(Kind::Build, compiler.stage, what, compiler.host, target)
-    }
-
     /// Return a `Group` guard for a [`Step`] that is built for each `--stage`.
     ///
     /// [`Step`]: crate::core::builder::Step
@@ -1117,7 +1106,7 @@ impl Build {
 
     #[must_use = "Groups should not be dropped until the Step finishes running"]
     #[track_caller]
-    fn msg_sysroot_tool(
+    fn msg_rustc_tool(
         &self,
         action: impl Into<Kind>,
         build_stage: u32,