bootstrap: Split off StepTask from the main Step trait

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

@@ -13,7 +13,8 @@ use crate::core::build_steps::tool::{
     prepare_tool_cargo,
 };
 use crate::core::builder::{
-    self, Alias, Builder, Cargo, Kind, RunConfig, ShouldRun, Step, StepMetadata, crate_description,
+    self, Alias, Builder, Cargo, Kind, RunConfig, ShouldRun, Step, StepMetadata, StepTask,
+    crate_description,
 };
 use crate::core::config::TargetSelection;
 use crate::utils::build_stamp::{self, BuildStamp};
@@ -219,13 +220,9 @@ impl PrepareRustcRmetaSysroot {
     }
 }
 
-impl Step for PrepareRustcRmetaSysroot {
+impl StepTask for PrepareRustcRmetaSysroot {
     type Output = RmetaSysroot;
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     fn run(self, builder: &Builder<'_>) -> Self::Output {
         // Check rustc
         let stamp = builder.ensure(Rustc::from_build_compiler(
@@ -263,13 +260,9 @@ impl PrepareStdRmetaSysroot {
     }
 }
 
-impl Step for PrepareStdRmetaSysroot {
+impl StepTask for PrepareStdRmetaSysroot {
     type Output = RmetaSysroot;
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     fn run(self, builder: &Builder<'_>) -> Self::Output {
         // Check std
         let stamp = builder.ensure(Std {

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

@@ -21,8 +21,9 @@ impl Step for CleanAll {
     type Output = ();
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        // Only runs as the default `./x clean` step; cannot be selected explicitly.
-        run.never()
+        // Normally this step is invoked implicitly via `./x clean`, but all
+        // steps are required to register at least one explicit path/alias.
+        run.alias("default")
     }
 
     fn is_default_step(_builder: &Builder<'_>) -> bool {

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

@@ -22,9 +22,9 @@ use tracing::span;
 use crate::core::build_steps::gcc::{Gcc, GccOutput, GccTargetPair};
 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::{
-    Builder, Cargo, Kind, RunConfig, ShouldRun, Step, StepMetadata, apply_pgo, crate_description,
+    self, Builder, Cargo, Kind, RunConfig, ShouldRun, Step, StepMetadata, StepTask, apply_pgo,
+    crate_description,
 };
 use crate::core::config::toml::target::DefaultLinuxLinkerOverride;
 use crate::core::config::{
@@ -740,13 +740,9 @@ impl StdLink {
     }
 }
 
-impl Step for StdLink {
+impl StepTask for StdLink {
     type Output = ();
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     /// Link all libstd rlibs/dylibs into the sysroot location.
     ///
     /// Links those artifacts generated by `compiler` to the `stage` compiler's
@@ -1530,13 +1526,9 @@ impl RustcLink {
     }
 }
 
-impl Step for RustcLink {
+impl StepTask for RustcLink {
     type Output = ();
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     /// Same as `StdLink`, only for librustc
     fn run(self, builder: &Builder<'_>) {
         let build_compiler = self.build_compiler;
@@ -1904,13 +1896,9 @@ impl Sysroot {
     }
 }
 
-impl Step for Sysroot {
+impl StepTask for Sysroot {
     type Output = PathBuf;
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     /// Returns the sysroot that `compiler` is supposed to use.
     /// For the stage0 compiler, this is stage0-sysroot (because of the initial std build).
     /// For all other stages, it's the same stage directory that the compiler lives in.

src/bootstrap/src/core/build_steps/dist.rs

@@ -29,7 +29,7 @@ use crate::core::build_steps::tool::{
 };
 use crate::core::build_steps::vendor::Vendor;
 use crate::core::build_steps::{compile, llvm};
-use crate::core::builder::{Builder, Kind, RunConfig, ShouldRun, Step, StepMetadata};
+use crate::core::builder::{Builder, Kind, RunConfig, ShouldRun, Step, StepMetadata, StepTask};
 use crate::core::config::{GccCiMode, TargetSelection};
 use crate::utils::build_stamp::{self, BuildStamp};
 use crate::utils::channel::{self, Info};
@@ -704,13 +704,9 @@ pub struct DebuggerScripts {
     pub target: TargetSelection,
 }
 
-impl Step for DebuggerScripts {
+impl StepTask for DebuggerScripts {
     type Output = ();
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     fn run(self, builder: &Builder<'_>) {
         let target = self.target;
         let sysroot = self.sysroot;

src/bootstrap/src/core/build_steps/doc.rs

@@ -16,7 +16,8 @@ use crate::core::build_steps::tool::{
     self, RustcPrivateCompilers, SourceType, Tool, prepare_tool_cargo,
 };
 use crate::core::builder::{
-    self, Builder, Compiler, Kind, RunConfig, ShouldRun, Step, StepMetadata, crate_description,
+    self, Builder, Compiler, Kind, RunConfig, ShouldRun, Step, StepMetadata, StepTask,
+    crate_description,
 };
 use crate::core::config::{Config, TargetSelection};
 use crate::helpers::{submodule_path_of, symlink_dir, t, up_to_date};
@@ -138,13 +139,9 @@ struct RustbookSrc<P: Step> {
     build_compiler: Option<Compiler>,
 }
 
-impl<P: Step> Step for RustbookSrc<P> {
+impl<P: Step> StepTask for RustbookSrc<P> {
     type Output = ();
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     /// Invoke `rustbook` for `target` for the doc book `name` from the `src` path.
     ///
     /// This will not actually generate any documentation if the documentation has
@@ -574,18 +571,9 @@ pub struct SharedAssets {
     target: TargetSelection,
 }
 
-impl Step for SharedAssets {
+impl StepTask for SharedAssets {
     type Output = SharedAssetsPaths;
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        // Other tasks depend on this, no need to execute it on its own
-        run.never()
-    }
-
-    fn is_default_step(_builder: &Builder<'_>) -> bool {
-        false
-    }
-
     /// Generate shared resources used by other pieces of documentation.
     fn run(self, builder: &Builder<'_>) -> Self::Output {
         let out = builder.doc_out(self.target);

src/bootstrap/src/core/build_steps/synthetic_targets.rs

@@ -8,7 +8,7 @@
 //! that calls create_synthetic_target.
 
 use crate::Compiler;
-use crate::core::builder::{Builder, ShouldRun, Step};
+use crate::core::builder::{Builder, StepTask};
 use crate::core::config::TargetSelection;
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -17,17 +17,9 @@ pub(crate) struct MirOptPanicAbortSyntheticTarget {
     pub(crate) base: TargetSelection,
 }
 
-impl Step for MirOptPanicAbortSyntheticTarget {
+impl StepTask for MirOptPanicAbortSyntheticTarget {
     type Output = TargetSelection;
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
-    fn is_default_step(_builder: &Builder<'_>) -> bool {
-        true
-    }
-
     fn run(self, builder: &Builder<'_>) -> Self::Output {
         create_synthetic_target(builder, self.compiler, "miropt-abort", self.base, |spec| {
             spec.insert("panic-strategy".into(), "abort".into());

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

@@ -28,7 +28,7 @@ use crate::core::build_steps::tool::{
 use crate::core::build_steps::toolstate::ToolState;
 use crate::core::build_steps::{compile, dist, llvm};
 use crate::core::builder::{
-    self, Alias, Builder, Compiler, Kind, RunConfig, ShouldRun, Step, StepMetadata,
+    self, Alias, Builder, Compiler, Kind, RunConfig, ShouldRun, Step, StepMetadata, StepTask,
     crate_description,
 };
 use crate::core::config::TargetSelection;
@@ -2129,13 +2129,9 @@ struct Compiletest {
     compare_mode: Option<&'static str>,
 }
 
-impl Step for Compiletest {
+impl StepTask for Compiletest {
     type Output = ();
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     fn run(self, builder: &Builder<'_>) {
         if builder.test_target == TestTarget::DocOnly {
             return;
@@ -2854,13 +2850,8 @@ struct BookTest {
     dependencies: Vec<&'static str>,
 }
 
-impl Step for BookTest {
+impl StepTask for BookTest {
     type Output = ();
-    const IS_HOST: bool = true;
-
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
 
     fn run(self, builder: &Builder<'_>) {
         // External docs are different from local because:
@@ -3663,13 +3654,9 @@ pub struct RemoteCopyLibs {
     target: TargetSelection,
 }
 
-impl Step for RemoteCopyLibs {
+impl StepTask for RemoteCopyLibs {
     type Output = ();
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     fn run(self, builder: &Builder<'_>) {
         let build_compiler = self.build_compiler;
         let target = self.target;

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

@@ -3,7 +3,7 @@ use std::fs::{self, File};
 use std::io::{BufRead, BufReader, ErrorKind};
 use std::path::{Path, PathBuf};
 
-use crate::core::builder::{Builder, ShouldRun, Step};
+use crate::core::builder::{Builder, StepTask};
 use crate::t;
 
 #[derive(Clone)]
@@ -29,13 +29,9 @@ impl RecordFailedTests {
 /// and the `RecordFailedTest` type doesn't (need to) signify anything.
 #[derive(Clone, Copy, Eq, PartialEq, Hash, Debug)]
 pub struct SetupFailedTestsFile;
-impl Step for SetupFailedTestsFile {
+impl StepTask for SetupFailedTestsFile {
     type Output = RecordFailedTests;
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     fn run(self, builder: &Builder<'_>) -> Self::Output {
         if !builder.config.cmd.record() || builder.config.dry_run() {
             return RecordFailedTests { failed_tests_path: None };

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

@@ -16,10 +16,9 @@ use std::{env, fs};
 use crate::core::build_steps::compile::is_lto_stage;
 use crate::core::build_steps::toolstate::ToolState;
 use crate::core::build_steps::{compile, llvm};
-use crate::core::builder;
 use crate::core::builder::{
-    Builder, Cargo as CargoCommand, RunConfig, ShouldRun, Step, StepMetadata, apply_pgo,
-    cargo_profile_var,
+    self, Builder, Cargo as CargoCommand, RunConfig, ShouldRun, Step, StepMetadata, StepTask,
+    apply_pgo, cargo_profile_var,
 };
 use crate::core::config::{DebuginfoLevel, RustcLto, TargetSelection};
 use crate::utils::exec::{BootstrapCommand, command};
@@ -66,13 +65,9 @@ pub struct ToolBuildResult {
     pub build_compiler: Compiler,
 }
 
-impl Step for ToolBuild {
+impl StepTask for ToolBuild {
     type Output = ToolBuildResult;
 
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
     /// Builds a tool in `src/tools`
     ///
     /// This will build the specified tool with the specified `host` compiler in
@@ -1239,17 +1234,8 @@ pub enum LibcxxVersion {
     Llvm(usize),
 }
 
-impl Step for LibcxxVersionTool {
+impl StepTask for LibcxxVersionTool {
     type Output = LibcxxVersion;
-    const IS_HOST: bool = true;
-
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
-    fn is_default_step(_builder: &Builder<'_>) -> bool {
-        false
-    }
 
     fn run(self, builder: &Builder<'_>) -> LibcxxVersion {
         let out_dir = builder.out.join(self.target.to_string()).join("libcxx-version");

src/bootstrap/src/core/builder/cli_paths/snapshots/x_clean.snap

@@ -4,4 +4,4 @@ expression: clean
 ---
 [Clean] clean::CleanAll
     targets: [aarch64-unknown-linux-gnu]
-    - Set({})
+    - Set({clean::default})