Enforce in bootstrap that check must have stage at least 1

src/bootstrap/defaults/bootstrap.library.toml

@@ -1,7 +1,6 @@
 # These defaults are meant for contributors to the standard library and documentation.
 [build]
 bench-stage = 1
-check-stage = 1
 test-stage = 1
 
 [rust]

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

@@ -215,7 +215,7 @@ impl Step for Rustc {
                 builder.std(compiler, compiler.host);
                 builder.std(compiler, target);
             } else {
-                builder.ensure(check::Std::new(target));
+                builder.ensure(check::Std::new(compiler, target));
             }
         }
 
@@ -287,7 +287,7 @@ macro_rules! lint_any {
                 let target = self.target;
 
                 if !builder.download_rustc() {
-                    builder.ensure(check::Rustc::new(target, builder));
+                    builder.ensure(check::Rustc::new(builder, compiler, target));
                 };
 
                 let cargo = prepare_tool_cargo(

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

@@ -1742,17 +1742,19 @@ fn copy_codegen_backends_to_sysroot(
         }
 
         let stamp = build_stamp::codegen_backend_stamp(builder, compiler, target, backend);
-        let dylib = t!(fs::read_to_string(stamp.path()));
-        let file = Path::new(&dylib);
-        let filename = file.file_name().unwrap().to_str().unwrap();
-        // change `librustc_codegen_cranelift-xxxxxx.so` to
-        // `librustc_codegen_cranelift-release.so`
-        let target_filename = {
-            let dash = filename.find('-').unwrap();
-            let dot = filename.find('.').unwrap();
-            format!("{}-{}{}", &filename[..dash], builder.rust_release(), &filename[dot..])
-        };
-        builder.copy_link(file, &dst.join(target_filename), FileType::NativeLibrary);
+        if stamp.path().exists() {
+            let dylib = t!(fs::read_to_string(stamp.path()));
+            let file = Path::new(&dylib);
+            let filename = file.file_name().unwrap().to_str().unwrap();
+            // change `librustc_codegen_cranelift-xxxxxx.so` to
+            // `librustc_codegen_cranelift-release.so`
+            let target_filename = {
+                let dash = filename.find('-').unwrap();
+                let dot = filename.find('.').unwrap();
+                format!("{}-{}{}", &filename[..dash], builder.rust_release(), &filename[dot..])
+            };
+            builder.copy_link(file, &dst.join(target_filename), FileType::NativeLibrary);
+        }
     }
 }
 
@@ -2163,6 +2165,25 @@ impl Step for Assemble {
                 continue; // Already built as part of rustc
             }
 
+            // FIXME: this is a horrible hack used to make `x check` work when other codegen
+            // backends are enabled.
+            // `x check` will check stage 1 rustc, which copies its rmetas to the stage0 sysroot.
+            // Then it checks codegen backends, which correctly use these rmetas.
+            // Then it needs to check std, but for that it needs to build stage 1 rustc.
+            // This copies the build rmetas into the stage0 sysroot, effectively poisoning it,
+            // because we then have both check and build rmetas in the same sysroot.
+            // That would be fine on its own. However, when another codegen backend is enabled,
+            // then building stage 1 rustc implies also building stage 1 codegen backend (even if
+            // it isn't used for anything). And since that tries to use the poisoned
+            // rmetas, it fails to build.
+            // We don't actually need to build rustc-private codegen backends for checking std,
+            // so instead we skip that.
+            // Note: this would be also an issue for other rustc-private tools, but that is "solved"
+            // by check::Std being last in the list of checked things (see
+            // `Builder::get_step_descriptions`).
+            if builder.kind == Kind::Check && builder.top_stage == 1 {
+                continue;
+            }
             builder.ensure(CodegenBackend {
                 compiler: build_compiler,
                 target: target_compiler.host,

src/bootstrap/src/core/build_steps/llvm.rs

@@ -263,6 +263,15 @@ impl Step for Llvm {
     }
 
     /// Compile LLVM for `target`.
+    #[cfg_attr(
+        feature = "tracing",
+        instrument(
+            level = "debug",
+            name = "Llvm::run",
+            skip_all,
+            fields(target = ?self.target),
+        ),
+    )]
     fn run(self, builder: &Builder<'_>) -> LlvmResult {
         let target = self.target;
         let target_native = if self.target.starts_with("riscv") {

src/bootstrap/src/core/build_steps/tool.rs

@@ -77,7 +77,7 @@ impl Builder<'_> {
                 *target,
             ),
             // doesn't depend on compiler, same as host compiler
-            _ => self.msg(Kind::Build, build_stage, format_args!("tool {tool}"), *host, *target),
+            _ => self.msg(kind, build_stage, format_args!("tool {tool}"), *host, *target),
         }
     }
 }

src/bootstrap/src/core/builder/tests.rs

@@ -1240,24 +1240,23 @@ mod snapshot {
             ctx.config("check")
                 .path("compiler")
                 .render_steps(), @r"
-        [check] std <host>
         [build] llvm <host>
-        [check] rustc <host>
-        [check] cranelift <host>
-        [check] gcc <host>
+        [check] rustc 0 <host> -> rustc 1 <host>
+        [check] rustc 0 <host> -> cranelift 1 <host>
+        [check] rustc 0 <host> -> gcc 1 <host>
         ");
 
         insta::assert_snapshot!(
             ctx.config("check")
                 .path("rustc")
                 .render_steps(), @r"
-        [check] std <host>
         [build] llvm <host>
-        [check] rustc <host>
+        [check] rustc 0 <host> -> rustc 1 <host>
         ");
     }
 
     #[test]
+    #[should_panic]
     fn check_compiler_stage_0() {
         let ctx = TestCtx::new();
         ctx.config("check").path("compiler").stage(0).run();
@@ -1272,11 +1271,9 @@ mod snapshot {
                 .stage(1)
                 .render_steps(), @r"
         [build] llvm <host>
-        [build] rustc 0 <host> -> rustc 1 <host>
-        [build] rustc 1 <host> -> std 1 <host>
-        [check] rustc <host>
-        [check] cranelift <host>
-        [check] gcc <host>
+        [check] rustc 0 <host> -> rustc 1 <host>
+        [check] rustc 0 <host> -> cranelift 1 <host>
+        [check] rustc 0 <host> -> gcc 1 <host>
         ");
     }
 
@@ -1291,11 +1288,9 @@ mod snapshot {
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
-        [build] rustc 1 <host> -> rustc 2 <host>
-        [build] rustc 2 <host> -> std 2 <host>
-        [check] rustc <host>
-        [check] cranelift <host>
-        [check] gcc <host>
+        [check] rustc 1 <host> -> rustc 2 <host>
+        [check] rustc 1 <host> -> cranelift 2 <host>
+        [check] rustc 1 <host> -> gcc 2 <host>
         ");
     }
 
@@ -1304,30 +1299,26 @@ mod snapshot {
         let ctx = TestCtx::new();
         insta::assert_snapshot!(
             ctx.config("check")
-                .stage(2)
                 .targets(&[TEST_TRIPLE_1])
                 .hosts(&[TEST_TRIPLE_1])
                 .render_steps(), @r"
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
-        [build] rustc 1 <host> -> rustc 2 <host>
-        [build] rustc 2 <host> -> std 2 <host>
         [build] rustc 1 <host> -> std 1 <target1>
-        [build] rustc 2 <host> -> std 2 <target1>
-        [check] rustc <target1>
-        [check] Rustdoc <target1>
-        [check] cranelift <target1>
-        [check] gcc <target1>
-        [check] Clippy <target1>
-        [check] Miri <target1>
-        [check] CargoMiri <target1>
-        [check] MiroptTestTools <target1>
-        [check] Rustfmt <target1>
-        [check] rust-analyzer <target1>
-        [check] TestFloatParse <target1>
-        [check] FeaturesStatusDump <target1>
-        [check] std <target1>
+        [check] rustc 1 <host> -> rustc 2 <target1>
+        [check] rustc 1 <host> -> Rustdoc 2 <target1>
+        [check] rustc 1 <host> -> cranelift 2 <target1>
+        [check] rustc 1 <host> -> gcc 2 <target1>
+        [check] rustc 1 <host> -> Clippy 2 <target1>
+        [check] rustc 1 <host> -> Miri 2 <target1>
+        [check] rustc 1 <host> -> CargoMiri 2 <target1>
+        [check] rustc 0 <host> -> MiroptTestTools 1 <target1>
+        [check] rustc 1 <host> -> Rustfmt 2 <target1>
+        [check] rustc 1 <host> -> rust-analyzer 2 <target1>
+        [check] rustc 1 <host> -> TestFloatParse 2 <target1>
+        [check] rustc 0 <host> -> FeaturesStatusDump 1 <target1>
+        [check] rustc 1 <host> -> std 1 <target1>
         ");
     }
 
@@ -1340,11 +1331,12 @@ mod snapshot {
                 .render_steps(), @r"
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
-        [check] std <host>
+        [check] rustc 1 <host> -> std 1 <host>
         ");
     }
 
     #[test]
+    #[should_panic]
     fn check_library_stage_0() {
         let ctx = TestCtx::new();
         ctx.config("check").path("library").stage(0).run();
@@ -1360,7 +1352,7 @@ mod snapshot {
                 .render_steps(), @r"
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
-        [check] std <host>
+        [check] rustc 1 <host> -> std 1 <host>
         ");
     }
 
@@ -1376,7 +1368,7 @@ mod snapshot {
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
         [build] rustc 1 <host> -> rustc 2 <host>
-        [check] std <host>
+        [check] rustc 2 <host> -> std 2 <host>
         ");
     }
 
@@ -1390,8 +1382,8 @@ mod snapshot {
                 .render_steps(), @r"
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
-        [check] std <target1>
-        [check] std <target2>
+        [check] rustc 1 <host> -> std 1 <target1>
+        [check] rustc 1 <host> -> std 1 <target2>
         ");
     }
 
@@ -1402,14 +1394,14 @@ mod snapshot {
             ctx.config("check")
                 .path("miri")
                 .render_steps(), @r"
-        [check] std <host>
         [build] llvm <host>
-        [check] rustc <host>
-        [check] Miri <host>
+        [check] rustc 0 <host> -> rustc 1 <host>
+        [check] rustc 0 <host> -> Miri 1 <host>
         ");
     }
 
     #[test]
+    #[should_panic]
     fn check_miri_stage_0() {
         let ctx = TestCtx::new();
         ctx.config("check").path("miri").stage(0).run();
@@ -1424,10 +1416,8 @@ mod snapshot {
                 .stage(1)
                 .render_steps(), @r"
         [build] llvm <host>
-        [build] rustc 0 <host> -> rustc 1 <host>
-        [build] rustc 1 <host> -> std 1 <host>
-        [check] rustc <host>
-        [check] Miri <host>
+        [check] rustc 0 <host> -> rustc 1 <host>
+        [check] rustc 0 <host> -> Miri 1 <host>
         ");
     }
 
@@ -1442,10 +1432,8 @@ mod snapshot {
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
-        [build] rustc 1 <host> -> rustc 2 <host>
-        [build] rustc 2 <host> -> std 2 <host>
-        [check] rustc <host>
-        [check] Miri <host>
+        [check] rustc 1 <host> -> rustc 2 <host>
+        [check] rustc 1 <host> -> Miri 2 <host>
         ");
     }
 
@@ -1466,9 +1454,9 @@ mod snapshot {
                 .path("compiletest")
                 .args(&["--set", "build.compiletest-use-stage0-libtest=false"])
                 .render_steps(), @r"
-        [check] std <host>
         [build] llvm <host>
-        [check] rustc <host>
+        [build] rustc 0 <host> -> rustc 1 <host>
+        [build] rustc 1 <host> -> std 1 <host>
         [check] compiletest <host>
         ");
     }
@@ -1480,11 +1468,10 @@ mod snapshot {
             ctx.config("check")
                 .path("rustc_codegen_cranelift")
                 .render_steps(), @r"
-        [check] std <host>
         [build] llvm <host>
-        [check] rustc <host>
-        [check] cranelift <host>
-        [check] gcc <host>
+        [check] rustc 0 <host> -> rustc 1 <host>
+        [check] rustc 0 <host> -> cranelift 1 <host>
+        [check] rustc 0 <host> -> gcc 1 <host>
         ");
     }
 
@@ -1495,10 +1482,9 @@ mod snapshot {
             ctx.config("check")
                 .path("rust-analyzer")
                 .render_steps(), @r"
-        [check] std <host>
         [build] llvm <host>
-        [check] rustc <host>
-        [check] rust-analyzer <host>
+        [check] rustc 0 <host> -> rustc 1 <host>
+        [check] rustc 0 <host> -> rust-analyzer 1 <host>
         ");
     }
 
@@ -1508,12 +1494,7 @@ mod snapshot {
         insta::assert_snapshot!(
             ctx.config("check")
                 .path("run-make-support")
-                .render_steps(), @r"
-        [check] std <host>
-        [build] llvm <host>
-        [check] rustc <host>
-        [check] RunMakeSupport <host>
-        ");
+                .render_steps(), @"[check] rustc 0 <host> -> RunMakeSupport 1 <host>");
     }
 
     #[test]

src/bootstrap/src/core/config/config.rs

@@ -1025,7 +1025,7 @@ impl Config {
             || bench_stage.is_some();
 
         config.stage = match config.cmd {
-            Subcommand::Check { .. } => flags_stage.or(check_stage).unwrap_or(0),
+            Subcommand::Check { .. } => flags_stage.or(check_stage).unwrap_or(1),
             Subcommand::Clippy { .. } | Subcommand::Fix => flags_stage.or(check_stage).unwrap_or(1),
             // `download-rustc` only has a speed-up for stage2 builds. Default to stage2 unless explicitly overridden.
             Subcommand::Doc { .. } => {
@@ -1052,9 +1052,16 @@ impl Config {
         };
 
         // Now check that the selected stage makes sense, and if not, print a warning and end
-        if let (0, Subcommand::Build) = (config.stage, &config.cmd) {
-            eprintln!("WARNING: cannot build anything on stage 0. Use at least stage 1.");
-            exit!(1);
+        match (config.stage, &config.cmd) {
+            (0, Subcommand::Build) => {
+                eprintln!("WARNING: cannot build anything on stage 0. Use at least stage 1.");
+                exit!(1);
+            }
+            (0, Subcommand::Check { .. }) => {
+                eprintln!("WARNING: cannot check anything on stage 0. Use at least stage 1.");
+                exit!(1);
+            }
+            _ => {}
         }
 
         // CI should always run stage 2 builds, unless it specifically states otherwise

src/bootstrap/src/utils/change_tracker.rs

@@ -446,4 +446,9 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
         severity: ChangeSeverity::Info,
         summary: "Added new option `build.tidy-extra-checks` to specify a default value for the --extra-checks cli flag.",
     },
+    ChangeInfo {
+        change_id: 143048,
+        severity: ChangeSeverity::Warning,
+        summary: "The default check stage has been changed to 1. It is no longer possible to `x check` with stage 0. All check commands have to be on stage 1+.",
+    },
 ];