Rollup merge of #111955 - jyn514:step-refactors, r=clubby789

bootstrap: Various Step refactors

This ended up being a bunch of only somewhat related changes, sorry :sweat: on the bright side, they're all fairly small  and well-commented in the commit messages.

- Document `ShouldRun::crates`

- Switch Steps from crates to crate_or_deps where possible

    and document why the single remaining place can't switch

- Switch doc::{Std, Rustc} to `crate_or_deps`

    Previously they were using `all_krates` and various hacks to determine
    which crates to document. Switch them to `crate_or_deps` so `ShouldRun`
    tells them which crate to document instead of having to guess.

    This also makes a few other refactors:
    - Remove the now unused `all_krates`; new code should only use
      `crate_or_deps`.
    - Add tests for documenting Std
    - Remove the unnecessary `run_cargo_rustdoc_for` closure so that we only
      run cargo once
    - Give a more helpful error message when documenting a no_std target
    - Use `builder.msg` in the Steps instead of `builder.info`

- Extend `msg` and `description` to work with any subcommand

    Previously `description` only supported `Testing` and `Benchmarking`,
    and `msg` gave weird results for `doc` (it would say `Docing`).

- Add a `make_run_crates` function and use it Rustc and Std

    This fixes the panic from the previous commit.

- Allow checking individual crates

    This is useful for profiling metadata generation.

    This comes very close to removing all_krates, but doesn't quite -
    there's one last usage left in `doc`. This is fixed in a later commit.

- Give a more helpful error when calling `cargo_crates_in_set` for an alias

    Before:
    ```
    thread 'main' panicked at 'no entry found for key', builder.rs:110:30
    ```

    After:
    ```
    thread 'main' panicked at 'missing crate for path library', check.rs:89:26
    ```

8 files changed, 225 insertions, 167 deletions

diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 2fa445506bc..30359e47e73 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -103,11 +103,14 @@ impl RunConfig<'_> {
     }
 
     /// Return a list of crate names selected by `run.paths`.
+    #[track_caller]
     pub fn cargo_crates_in_set(&self) -> Interned<Vec<String>> {
         let mut crates = Vec::new();
         for krate in &self.paths {
             let path = krate.assert_single_path();
-            let crate_name = self.builder.crate_paths[&path.path];
+            let Some(crate_name) = self.builder.crate_paths.get(&path.path) else {
+                panic!("missing crate for path {}", path.path.display())
+            };
             crates.push(crate_name.to_string());
         }
         INTERNER.intern_list(crates)
@@ -430,25 +433,6 @@ impl<'a> ShouldRun<'a> {
     /// Indicates it should run if the command-line selects the given crate or
     /// any of its (local) dependencies.
     ///
-    /// Compared to `krate`, this treats the dependencies as aliases for the
-    /// same job. Generally it is preferred to use `krate`, and treat each
-    /// individual path separately. For example `./x.py test src/liballoc`
-    /// (which uses `krate`) will test just `liballoc`. However, `./x.py check
-    /// src/liballoc` (which uses `all_krates`) will check all of `libtest`.
-    /// `all_krates` should probably be removed at some point.
-    pub fn all_krates(mut self, name: &str) -> Self {
-        let mut set = BTreeSet::new();
-        for krate in self.builder.in_tree_crates(name, None) {
-            let path = krate.local_path(self.builder);
-            set.insert(TaskPath { path, kind: Some(self.kind) });
-        }
-        self.paths.insert(PathSet::Set(set));
-        self
-    }
-
-    /// Indicates it should run if the command-line selects the given crate or
-    /// any of its (local) dependencies.
-    ///
     /// `make_run` will be called a single time with all matching command-line paths.
     pub fn crate_or_deps(self, name: &str) -> Self {
         let crates = self.builder.in_tree_crates(name, None);
@@ -458,6 +442,8 @@ impl<'a> ShouldRun<'a> {
     /// Indicates it should run if the command-line selects any of the given crates.
     ///
     /// `make_run` will be called a single time with all matching command-line paths.
+    ///
+    /// Prefer [`ShouldRun::crate_or_deps`] to this function where possible.
     pub(crate) fn crates(mut self, crates: Vec<&Crate>) -> Self {
         for krate in crates {
             let path = krate.local_path(self.builder);
@@ -487,7 +473,15 @@ impl<'a> ShouldRun<'a> {
         self.paths(&[path])
     }
 
-    // multiple aliases for the same job
+    /// Multiple aliases for the same job.
+    ///
+    /// This differs from [`path`] in that multiple calls to path will end up calling `make_run`
+    /// multiple times, whereas a single call to `paths` will only ever generate a single call to
+    /// `paths`.
+    ///
+    /// This is analogous to `all_krates`, although `all_krates` is gone now. Prefer [`path`] where possible.
+    ///
+    /// [`path`]: ShouldRun::path
     pub fn paths(mut self, paths: &[&str]) -> Self {
         static SUBMODULES_PATHS: OnceCell<Vec<String>> = OnceCell::new();
 
@@ -641,12 +635,16 @@ impl Kind {
         }
     }
 
-    pub fn test_description(&self) -> &'static str {
+    pub fn description(&self) -> String {
         match self {
             Kind::Test => "Testing",
             Kind::Bench => "Benchmarking",
-            _ => panic!("not a test command: {}!", self.as_str()),
+            Kind::Doc => "Documenting",
+            Kind::Run => "Running",
+            Kind::Suggest => "Suggesting",
+            _ => return format!("{self:?}"),
         }
+        .to_owned()
     }
 }
 
diff --git a/src/bootstrap/builder/tests.rs b/src/bootstrap/builder/tests.rs
index edca8fe9b13..d76b830b0e5 100644
--- a/src/bootstrap/builder/tests.rs
+++ b/src/bootstrap/builder/tests.rs
@@ -1,5 +1,6 @@
 use super::*;
 use crate::config::{Config, DryRun, TargetSelection};
+use crate::doc::DocumentationFormat;
 use std::thread;
 
 fn configure(cmd: &str, host: &[&str], target: &[&str]) -> Config {
@@ -66,6 +67,16 @@ macro_rules! std {
     };
 }
 
+macro_rules! doc_std {
+    ($host:ident => $target:ident, stage = $stage:literal) => {
+        doc::Std::new(
+            $stage,
+            TargetSelection::from_user(stringify!($target)),
+            DocumentationFormat::HTML,
+        )
+    };
+}
+
 macro_rules! rustc {
     ($host:ident => $target:ident, stage = $stage:literal) => {
         compile::Rustc::new(
@@ -144,6 +155,9 @@ fn alias_and_path_for_library() {
         first(cache.all::<compile::Std>()),
         &[std!(A => A, stage = 0), std!(A => A, stage = 1)]
     );
+
+    let mut cache = run_build(&["library".into(), "core".into()], configure("doc", &["A"], &["A"]));
+    assert_eq!(first(cache.all::<doc::Std>()), &[doc_std!(A => A, stage = 0)]);
 }
 
 #[test]
diff --git a/src/bootstrap/check.rs b/src/bootstrap/check.rs
index b11be96cefe..f5a93854bf2 100644
--- a/src/bootstrap/check.rs
+++ b/src/bootstrap/check.rs
@@ -1,8 +1,10 @@
 //! Implementation of compiling the compiler and standard library, in "check"-based modes.
 
-use crate::builder::{Builder, Kind, RunConfig, ShouldRun, Step};
+use crate::builder::{crate_description, Builder, Kind, RunConfig, ShouldRun, Step};
 use crate::cache::Interned;
-use crate::compile::{add_to_sysroot, run_cargo, rustc_cargo, rustc_cargo_env, std_cargo};
+use crate::compile::{
+    add_to_sysroot, make_run_crates, run_cargo, rustc_cargo, rustc_cargo_env, std_cargo,
+};
 use crate::config::TargetSelection;
 use crate::tool::{prepare_tool_cargo, SourceType};
 use crate::INTERNER;
@@ -12,6 +14,12 @@ use std::path::{Path, PathBuf};
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct Std {
     pub target: TargetSelection,
+    /// Whether to build only a subset of crates.
+    ///
+    /// This shouldn't be used from other steps; see the comment on [`compile::Rustc`].
+    ///
+    /// [`compile::Rustc`]: crate::compile::Rustc
+    crates: Interned<Vec<String>>,
 }
 
 /// Returns args for the subcommand itself (not for cargo)
@@ -66,16 +74,23 @@ fn cargo_subcommand(kind: Kind) -> &'static str {
     }
 }
 
+impl Std {
+    pub fn new(target: TargetSelection) -> Self {
+        Self { target, crates: INTERNER.intern_list(vec![]) }
+    }
+}
+
 impl Step for Std {
     type Output = ();
     const DEFAULT: bool = true;
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.all_krates("sysroot").path("library")
+        run.crate_or_deps("sysroot").path("library")
     }
 
     fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(Std { target: run.target });
+        let crates = make_run_crates(&run, "library");
+        run.builder.ensure(Std { target: run.target, crates });
     }
 
     fn run(self, builder: &Builder<'_>) {
@@ -97,7 +112,14 @@ impl Step for Std {
             cargo.arg("--lib");
         }
 
-        let _guard = builder.msg_check("library artifacts", target);
+        for krate in &*self.crates {
+            cargo.arg("-p").arg(krate);
+        }
+
+        let _guard = builder.msg_check(
+            format_args!("library artifacts{}", crate_description(&self.crates)),
+            target,
+        );
         run_cargo(
             builder,
             cargo,
@@ -117,7 +139,8 @@ impl Step for Std {
         }
 
         // don't run on std twice with x.py clippy
-        if builder.kind == Kind::Clippy {
+        // don't check test dependencies if we haven't built libtest
+        if builder.kind == Kind::Clippy || !self.crates.is_empty() {
             return;
         }
 
@@ -147,8 +170,8 @@ impl Step for Std {
         // Explicitly pass -p for all dependencies krates -- this will force cargo
         // to also check the tests/benches/examples for these crates, rather
         // than just the leaf crate.
-        for krate in builder.in_tree_crates("test", Some(target)) {
-            cargo.arg("-p").arg(krate.name);
+        for krate in &*self.crates {
+            cargo.arg("-p").arg(krate);
         }
 
         let _guard = builder.msg_check("library test/bench/example targets", target);
@@ -167,6 +190,22 @@ impl Step for Std {
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct Rustc {
     pub target: TargetSelection,
+    /// Whether to build only a subset of crates.
+    ///
+    /// This shouldn't be used from other steps; see the comment on [`compile::Rustc`].
+    ///
+    /// [`compile::Rustc`]: crate::compile::Rustc
+    crates: Interned<Vec<String>>,
+}
+
+impl Rustc {
+    pub fn new(target: TargetSelection, builder: &Builder<'_>) -> Self {
+        let mut crates = vec![];
+        for krate in builder.in_tree_crates("rustc-main", None) {
+            crates.push(krate.name.to_string());
+        }
+        Self { target, crates: INTERNER.intern_list(crates) }
+    }
 }
 
 impl Step for Rustc {
@@ -175,11 +214,12 @@ impl Step for Rustc {
     const DEFAULT: bool = true;
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.all_krates("rustc-main").path("compiler")
+        run.crate_or_deps("rustc-main").path("compiler")
     }
 
     fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(Rustc { target: run.target });
+        let crates = make_run_crates(&run, "compiler");
+        run.builder.ensure(Rustc { target: run.target, crates });
     }
 
     /// Builds the compiler.
@@ -200,7 +240,7 @@ impl Step for Rustc {
             builder.ensure(crate::compile::Std::new(compiler, compiler.host));
             builder.ensure(crate::compile::Std::new(compiler, target));
         } else {
-            builder.ensure(Std { target });
+            builder.ensure(Std::new(target));
         }
 
         let mut cargo = builder.cargo(
@@ -218,14 +258,17 @@ impl Step for Rustc {
             cargo.arg("--all-targets");
         }
 
-        // Explicitly pass -p for all compiler krates -- this will force cargo
+        // Explicitly pass -p for all compiler crates -- this will force cargo
         // to also check the tests/benches/examples for these crates, rather
         // than just the leaf crate.
-        for krate in builder.in_tree_crates("rustc-main", Some(target)) {
-            cargo.arg("-p").arg(krate.name);
+        for krate in &*self.crates {
+            cargo.arg("-p").arg(krate);
         }
 
-        let _guard = builder.msg_check("compiler artifacts", target);
+        let _guard = builder.msg_check(
+            format_args!("compiler artifacts{}", crate_description(&self.crates)),
+            target,
+        );
         run_cargo(
             builder,
             cargo,
@@ -268,7 +311,7 @@ impl Step for CodegenBackend {
         let target = self.target;
         let backend = self.backend;
 
-        builder.ensure(Rustc { target });
+        builder.ensure(Rustc::new(target, builder));
 
         let mut cargo = builder.cargo(
             compiler,
@@ -318,7 +361,7 @@ impl Step for RustAnalyzer {
         let compiler = builder.compiler(builder.top_stage, builder.config.build);
         let target = self.target;
 
-        builder.ensure(Std { target });
+        builder.ensure(Std::new(target));
 
         let mut cargo = prepare_tool_cargo(
             builder,
@@ -386,7 +429,7 @@ macro_rules! tool_check_step {
                 let compiler = builder.compiler(builder.top_stage, builder.config.build);
                 let target = self.target;
 
-                builder.ensure(Rustc { target });
+                builder.ensure(Rustc::new(target, builder));
 
                 let mut cargo = prepare_tool_cargo(
                     builder,
diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index 33addb90da3..a7ebd018a87 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -48,6 +48,17 @@ impl Std {
     }
 }
 
+/// Given an `alias` selected by the `Step` and the paths passed on the command line,
+/// return a list of the crates that should be built.
+///
+/// Normally, people will pass *just* `library` if they pass it.
+/// But it's possible (although strange) to pass something like `library std core`.
+/// Build all crates anyway, as if they hadn't passed the other args.
+pub(crate) fn make_run_crates(run: &RunConfig<'_>, alias: &str) -> Interned<Vec<String>> {
+    let has_alias = run.paths.iter().any(|set| set.assert_single_path().path.ends_with(alias));
+    if has_alias { Default::default() } else { run.cargo_crates_in_set() }
+}
+
 impl Step for Std {
     type Output = ();
     const DEFAULT: bool = true;
@@ -62,16 +73,10 @@ impl Step for Std {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        // Normally, people will pass *just* library if they pass it.
-        // But it's possible (although strange) to pass something like `library std core`.
-        // Build all crates anyway, as if they hadn't passed the other args.
-        let has_library =
-            run.paths.iter().any(|set| set.assert_single_path().path.ends_with("library"));
-        let crates = if has_library { Default::default() } else { run.cargo_crates_in_set() };
         run.builder.ensure(Std {
             compiler: run.builder.compiler(run.builder.top_stage, run.build_triple()),
             target: run.target,
-            crates,
+            crates: make_run_crates(&run, "library"),
         });
     }
 
@@ -615,6 +620,8 @@ impl Step for Rustc {
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
         let mut crates = run.builder.in_tree_crates("rustc-main", None);
         for (i, krate) in crates.iter().enumerate() {
+            // We can't allow `build rustc` as an alias for this Step, because that's reserved by `Assemble`.
+            // Ideally Assemble would use `build compiler` instead, but that seems too confusing to be worth the breaking change.
             if krate.name == "rustc-main" {
                 crates.swap_remove(i);
                 break;
diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index b49845386da..46fc5b80e99 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -106,11 +106,7 @@ impl Step for JsonDocs {
     /// Builds the `rust-docs-json` installer component.
     fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
         let host = self.host;
-        builder.ensure(crate::doc::Std {
-            stage: builder.top_stage,
-            target: host,
-            format: DocumentationFormat::JSON,
-        });
+        builder.ensure(crate::doc::Std::new(builder.top_stage, host, DocumentationFormat::JSON));
 
         let dest = "share/doc/rust/json";
 
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index b52c3b68cc4..3de85c91516 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -7,7 +7,6 @@
 //! Everything here is basically just a shim around calling either `rustbook` or
 //! `rustdoc`.
 
-use std::ffi::OsStr;
 use std::fs;
 use std::io;
 use std::path::{Path, PathBuf};
@@ -16,6 +15,7 @@ use crate::builder::crate_description;
 use crate::builder::{Builder, Compiler, Kind, RunConfig, ShouldRun, Step};
 use crate::cache::{Interned, INTERNER};
 use crate::compile;
+use crate::compile::make_run_crates;
 use crate::config::{Config, TargetSelection};
 use crate::tool::{self, prepare_tool_cargo, SourceType, Tool};
 use crate::util::{symlink_dir, t, up_to_date};
@@ -87,15 +87,6 @@ book!(
     StyleGuide, "src/doc/style-guide", "style-guide";
 );
 
-// "library/std" -> ["library", "std"]
-//
-// Used for deciding whether a particular step is one requested by the user on
-// the `x.py doc` command line, which determines whether `--open` will open that
-// page.
-pub(crate) fn components_simplified(path: &PathBuf) -> Vec<&str> {
-    path.iter().map(|component| component.to_str().unwrap_or("???")).collect()
-}
-
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct UnstableBook {
     target: TargetSelection,
@@ -425,11 +416,18 @@ impl Step for SharedAssets {
     }
 }
 
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Std {
     pub stage: u32,
     pub target: TargetSelection,
     pub format: DocumentationFormat,
+    crates: Interned<Vec<String>>,
+}
+
+impl Std {
+    pub(crate) fn new(stage: u32, target: TargetSelection, format: DocumentationFormat) -> Self {
+        Std { stage, target, format, crates: INTERNER.intern_list(vec![]) }
+    }
 }
 
 impl Step for Std {
@@ -438,7 +436,7 @@ impl Step for Std {
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
         let builder = run.builder;
-        run.all_krates("sysroot").path("library").default_condition(builder.config.docs)
+        run.crate_or_deps("sysroot").path("library").default_condition(builder.config.docs)
     }
 
     fn make_run(run: RunConfig<'_>) {
@@ -450,6 +448,7 @@ impl Step for Std {
             } else {
                 DocumentationFormat::HTML
             },
+            crates: make_run_crates(&run, "library"),
         });
     }
 
@@ -457,7 +456,7 @@ impl Step for Std {
     ///
     /// This will generate all documentation for the standard library and its
     /// dependencies. This is largely just a wrapper around `cargo doc`.
-    fn run(self, builder: &Builder<'_>) {
+    fn run(mut self, builder: &Builder<'_>) {
         let stage = self.stage;
         let target = self.target;
         let out = match self.format {
@@ -471,41 +470,24 @@ impl Step for Std {
             builder.ensure(SharedAssets { target: self.target });
         }
 
-        let index_page = builder.src.join("src/doc/index.md").into_os_string();
+        let index_page = builder
+            .src
+            .join("src/doc/index.md")
+            .into_os_string()
+            .into_string()
+            .expect("non-utf8 paths are unsupported");
         let mut extra_args = match self.format {
-            DocumentationFormat::HTML => vec![
-                OsStr::new("--markdown-css"),
-                OsStr::new("rust.css"),
-                OsStr::new("--markdown-no-toc"),
-                OsStr::new("--index-page"),
-                &index_page,
-            ],
-            DocumentationFormat::JSON => vec![OsStr::new("--output-format"), OsStr::new("json")],
+            DocumentationFormat::HTML => {
+                vec!["--markdown-css", "rust.css", "--markdown-no-toc", "--index-page", &index_page]
+            }
+            DocumentationFormat::JSON => vec!["--output-format", "json"],
         };
 
         if !builder.config.docs_minification {
-            extra_args.push(OsStr::new("--disable-minification"));
+            extra_args.push("--disable-minification");
         }
 
-        let requested_crates = builder
-            .paths
-            .iter()
-            .map(components_simplified)
-            .filter_map(|path| {
-                if path.len() >= 2 && path.get(0) == Some(&"library") {
-                    // single crate
-                    Some(path[1].to_owned())
-                } else if !path.is_empty() {
-                    // ??
-                    Some(path[0].to_owned())
-                } else {
-                    // all library crates
-                    None
-                }
-            })
-            .collect::<Vec<_>>();
-
-        doc_std(builder, self.format, stage, target, &out, &extra_args, &requested_crates);
+        doc_std(builder, self.format, stage, target, &out, &extra_args, &self.crates);
 
         // Don't open if the format is json
         if let DocumentationFormat::JSON = self.format {
@@ -514,7 +496,11 @@ impl Step for Std {
 
         // Look for library/std, library/core etc in the `x.py doc` arguments and
         // open the corresponding rendered docs.
-        for requested_crate in requested_crates {
+        if self.crates.is_empty() {
+            self.crates = INTERNER.intern_list(vec!["library".to_owned()]);
+        };
+
+        for requested_crate in &*self.crates {
             if requested_crate == "library" {
                 // For `x.py doc library --open`, open `std` by default.
                 let index = out.join("std").join("index.html");
@@ -538,7 +524,7 @@ impl Step for Std {
 /// or remote link.
 const STD_PUBLIC_CRATES: [&str; 5] = ["core", "alloc", "std", "proc_macro", "test"];
 
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
 pub enum DocumentationFormat {
     HTML,
     JSON,
@@ -563,24 +549,22 @@ fn doc_std(
     stage: u32,
     target: TargetSelection,
     out: &Path,
-    extra_args: &[&OsStr],
+    extra_args: &[&str],
     requested_crates: &[String],
 ) {
-    builder.info(&format!(
-        "Documenting{} stage{} library ({}) in {} format",
-        crate_description(requested_crates),
-        stage,
-        target,
-        format.as_str()
-    ));
     if builder.no_std(target) == Some(true) {
         panic!(
             "building std documentation for no_std target {target} is not supported\n\
-             Set `docs = false` in the config to disable documentation."
+             Set `docs = false` in the config to disable documentation, or pass `--exclude doc::library`."
         );
     }
+
     let compiler = builder.compiler(stage, builder.config.build);
 
+    let description =
+        format!("library{} in {} format", crate_description(&requested_crates), format.as_str());
+    let _guard = builder.msg(Kind::Doc, stage, &description, compiler.host, target);
+
     let target_doc_dir_name = if format == DocumentationFormat::JSON { "json-doc" } else { "doc" };
     let target_dir =
         builder.stage_out(compiler, Mode::Std).join(target.triple).join(target_doc_dir_name);
@@ -590,35 +574,42 @@ fn doc_std(
     // as a function parameter.
     let out_dir = target_dir.join(target.triple).join("doc");
 
-    let run_cargo_rustdoc_for = |package: &str| {
-        let mut cargo = builder.cargo(compiler, Mode::Std, SourceType::InTree, target, "rustdoc");
-        compile::std_cargo(builder, target, compiler.stage, &mut cargo);
-        cargo
-            .arg("--target-dir")
-            .arg(&*target_dir.to_string_lossy())
-            .arg("-p")
-            .arg(package)
-            .arg("-Zskip-rustdoc-fingerprint")
-            .arg("--")
-            .arg("-Z")
-            .arg("unstable-options")
-            .arg("--resource-suffix")
-            .arg(&builder.version)
-            .args(extra_args);
-        if builder.config.library_docs_private_items {
-            cargo.arg("--document-private-items").arg("--document-hidden-items");
-        }
-        builder.run(&mut cargo.into());
+    let mut cargo = builder.cargo(compiler, Mode::Std, SourceType::InTree, target, "doc");
+    compile::std_cargo(builder, target, compiler.stage, &mut cargo);
+    cargo
+        .arg("--no-deps")
+        .arg("--target-dir")
+        .arg(&*target_dir.to_string_lossy())
+        .arg("-Zskip-rustdoc-fingerprint")
+        .rustdocflag("-Z")
+        .rustdocflag("unstable-options")
+        .rustdocflag("--resource-suffix")
+        .rustdocflag(&builder.version);
+    for arg in extra_args {
+        cargo.rustdocflag(arg);
+    }
+
+    if builder.config.library_docs_private_items {
+        cargo.rustdocflag("--document-private-items").rustdocflag("--document-hidden-items");
+    }
+
+    // HACK: because we use `--manifest-path library/sysroot/Cargo.toml`, cargo thinks we only want to document that specific crate, not its dependencies.
+    // Override its default.
+    let built_crates = if requested_crates.is_empty() {
+        builder
+            .in_tree_crates("sysroot", None)
+            .into_iter()
+            .map(|krate| krate.name.to_string())
+            .collect()
+    } else {
+        requested_crates.to_vec()
     };
 
-    for krate in STD_PUBLIC_CRATES {
-        run_cargo_rustdoc_for(krate);
-        if requested_crates.iter().any(|p| p == krate) {
-            // No need to document more of the libraries if we have the one we want.
-            break;
-        }
+    for krate in built_crates {
+        cargo.arg("-p").arg(krate);
     }
 
+    builder.run(&mut cargo.into());
     builder.cp_r(&out_dir, &out);
 }
 
@@ -626,6 +617,28 @@ fn doc_std(
 pub struct Rustc {
     pub stage: u32,
     pub target: TargetSelection,
+    crates: Interned<Vec<String>>,
+}
+
+impl Rustc {
+    pub(crate) fn new(stage: u32, target: TargetSelection, builder: &Builder<'_>) -> Self {
+        // Find dependencies for top level crates.
+        let root_crates = vec![
+            INTERNER.intern_str("rustc_driver"),
+            INTERNER.intern_str("rustc_codegen_llvm"),
+            INTERNER.intern_str("rustc_codegen_ssa"),
+        ];
+        let crates: Vec<_> = root_crates
+            .iter()
+            .flat_map(|krate| {
+                builder
+                    .in_tree_crates(krate, Some(target))
+                    .into_iter()
+                    .map(|krate| krate.name.to_string())
+            })
+            .collect();
+        Self { stage, target, crates: INTERNER.intern_list(crates) }
+    }
 }
 
 impl Step for Rustc {
@@ -641,7 +654,11 @@ impl Step for Rustc {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(Rustc { stage: run.builder.top_stage, target: run.target });
+        run.builder.ensure(Rustc {
+            stage: run.builder.top_stage,
+            target: run.target,
+            crates: make_run_crates(&run, "compiler"),
+        });
     }
 
     /// Generates compiler documentation.
@@ -654,15 +671,6 @@ impl Step for Rustc {
         let stage = self.stage;
         let target = self.target;
 
-        let paths = builder
-            .paths
-            .iter()
-            .filter(|path| {
-                let components = components_simplified(path);
-                components.len() >= 2 && components[0] == "compiler"
-            })
-            .collect::<Vec<_>>();
-
         // This is the intended out directory for compiler documentation.
         let out = builder.compiler_doc_out(target);
         t!(fs::create_dir_all(&out));
@@ -672,7 +680,13 @@ impl Step for Rustc {
         let compiler = builder.compiler(stage, builder.config.build);
         builder.ensure(compile::Std::new(compiler, builder.config.build));
 
-        builder.info(&format!("Documenting stage{} compiler ({})", stage, target));
+        let _guard = builder.msg(
+            Kind::Doc,
+            stage,
+            &format!("compiler{}", crate_description(&self.crates)),
+            compiler.host,
+            target,
+        );
 
         // This uses a shared directory so that librustdoc documentation gets
         // correctly built and merged with the rustc documentation. This is
@@ -710,22 +724,8 @@ impl Step for Rustc {
         cargo.rustdocflag("--extern-html-root-url");
         cargo.rustdocflag("ena=https://docs.rs/ena/latest/");
 
-        let root_crates = if paths.is_empty() {
-            vec![
-                INTERNER.intern_str("rustc_driver"),
-                INTERNER.intern_str("rustc_codegen_llvm"),
-                INTERNER.intern_str("rustc_codegen_ssa"),
-            ]
-        } else {
-            paths.into_iter().map(|p| builder.crate_paths[p]).collect()
-        };
-        // Find dependencies for top level crates.
-        let compiler_crates = root_crates.iter().flat_map(|krate| {
-            builder.in_tree_crates(krate, Some(target)).into_iter().map(|krate| krate.name)
-        });
-
         let mut to_open = None;
-        for krate in compiler_crates {
+        for krate in &*self.crates {
             // Create all crate output directories first to make sure rustdoc uses
             // relative links.
             // FIXME: Cargo should probably do this itself.
@@ -785,7 +785,7 @@ macro_rules! tool_doc {
 
                 if true $(&& $rustc_tool)? {
                     // Build rustc docs so that we generate relative links.
-                    builder.ensure(Rustc { stage, target });
+                    builder.ensure(Rustc::new(stage, target, builder));
 
                     // Rustdoc needs the rustc sysroot available to build.
                     // FIXME: is there a way to only ensure `check::Rustc` here? Last time I tried it failed
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index fb76dffd071..f7d30de67eb 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -1020,8 +1020,8 @@ impl Build {
         host: impl Into<Option<TargetSelection>>,
         target: impl Into<Option<TargetSelection>>,
     ) -> Option<gha::Group> {
-        let action = action.into();
-        let msg = |fmt| format!("{action:?}ing stage{stage} {what}{fmt}");
+        let action = action.into().description();
+        let msg = |fmt| format!("{action} stage{stage} {what}{fmt}");
         let msg = if let Some(target) = target.into() {
             let host = host.into().unwrap();
             if host == target {
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index 44cd84be705..960abb31b20 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -101,7 +101,7 @@ impl Step for CrateBootstrap {
         );
         builder.info(&format!(
             "{} {} stage0 ({})",
-            builder.kind.test_description(),
+            builder.kind.description(),
             path,
             bootstrap_host,
         ));
@@ -220,7 +220,7 @@ impl Step for HtmlCheck {
         }
         // Ensure that a few different kinds of documentation are available.
         builder.default_doc(&[]);
-        builder.ensure(crate::doc::Rustc { target: self.target, stage: builder.top_stage });
+        builder.ensure(crate::doc::Rustc::new(builder.top_stage, self.target, builder));
 
         try_run(builder, builder.tool_cmd(Tool::HtmlChecker).arg(builder.doc_out(self.target)));
     }
@@ -886,11 +886,11 @@ impl Step for RustdocJSStd {
                     command.arg("--test-file").arg(path);
                 }
             }
-            builder.ensure(crate::doc::Std {
-                target: self.target,
-                stage: builder.top_stage,
-                format: DocumentationFormat::HTML,
-            });
+            builder.ensure(crate::doc::Std::new(
+                builder.top_stage,
+                self.target,
+                DocumentationFormat::HTML,
+            ));
             builder.run(&mut command);
         } else {
             builder.info("No nodejs found, skipping \"tests/rustdoc-js-std\" tests");