Tests for number of times rustdoc is built with x.py test and doc.

src/bootstrap/builder/tests.rs

@@ -54,6 +54,11 @@ fn dist_baseline() {
         &[dist::Std { compiler: Compiler { host: a, stage: 1 }, target: a },]
     );
     assert_eq!(first(builder.cache.all::<dist::Src>()), &[dist::Src]);
+    // Make sure rustdoc is only built once.
+    assert_eq!(
+        first(builder.cache.all::<tool::Rustdoc>()),
+        &[tool::Rustdoc { compiler: Compiler { host: a, stage: 2 } },]
+    );
 }
 
 #[test]
@@ -414,3 +419,77 @@ fn test_exclude() {
     // Ensure other tests are not affected.
     assert!(builder.cache.contains::<test::RustdocUi>());
 }
+
+#[test]
+fn doc_default() {
+    let mut config = configure(&[], &[]);
+    config.compiler_docs = true;
+    config.cmd = Subcommand::Doc { paths: Vec::new(), open: false };
+    let build = Build::new(config);
+    let mut builder = Builder::new(&build);
+    builder.run_step_descriptions(&Builder::get_step_descriptions(Kind::Doc), &[]);
+    let a = INTERNER.intern_str("A");
+
+    // error_index_generator uses stage 1 to share rustdoc artifacts with the
+    // rustdoc tool.
+    assert_eq!(
+        first(builder.cache.all::<doc::ErrorIndex>()),
+        &[doc::ErrorIndex { compiler: Compiler { host: a, stage: 1 }, target: a },]
+    );
+    assert_eq!(
+        first(builder.cache.all::<tool::ErrorIndex>()),
+        &[tool::ErrorIndex { compiler: Compiler { host: a, stage: 1 } }]
+    );
+    // This is actually stage 1, but Rustdoc::run swaps out the compiler with
+    // stage minus 1 if --stage is not 0. Very confusing!
+    assert_eq!(
+        first(builder.cache.all::<tool::Rustdoc>()),
+        &[tool::Rustdoc { compiler: Compiler { host: a, stage: 2 } },]
+    );
+}
+
+#[test]
+fn test_docs() {
+    // Behavior of `x.py test` doing various documentation tests.
+    let mut config = configure(&[], &[]);
+    config.cmd = Subcommand::Test {
+        paths: vec![],
+        test_args: vec![],
+        rustc_args: vec![],
+        fail_fast: true,
+        doc_tests: DocTests::Yes,
+        bless: false,
+        compare_mode: None,
+        rustfix_coverage: false,
+        pass: None,
+    };
+    let build = Build::new(config);
+    let mut builder = Builder::new(&build);
+    builder.run_step_descriptions(&Builder::get_step_descriptions(Kind::Test), &[]);
+    let a = INTERNER.intern_str("A");
+
+    // error_index_generator uses stage 1 to share rustdoc artifacts with the
+    // rustdoc tool.
+    assert_eq!(
+        first(builder.cache.all::<doc::ErrorIndex>()),
+        &[doc::ErrorIndex { compiler: Compiler { host: a, stage: 1 }, target: a },]
+    );
+    assert_eq!(
+        first(builder.cache.all::<tool::ErrorIndex>()),
+        &[tool::ErrorIndex { compiler: Compiler { host: a, stage: 1 } }]
+    );
+    // Unfortunately rustdoc is built twice. Once from stage1 for compiletest
+    // (and other things), and once from stage0 for std crates. Ideally it
+    // would only be built once. If someone wants to fix this, it might be
+    // worth investigating if it would be possible to test std from stage1.
+    // Note that the stages here are +1 than what they actually are because
+    // Rustdoc::run swaps out the compiler with stage minus 1 if --stage is
+    // not 0.
+    assert_eq!(
+        first(builder.cache.all::<tool::Rustdoc>()),
+        &[
+            tool::Rustdoc { compiler: Compiler { host: a, stage: 1 } },
+            tool::Rustdoc { compiler: Compiler { host: a, stage: 2 } },
+        ]
+    );
+}

src/bootstrap/doc.rs

@@ -637,9 +637,10 @@ impl Step for Rustdoc {
     }
 }
 
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+#[derive(Ord, PartialOrd, Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct ErrorIndex {
-    target: Interned<String>,
+    pub compiler: Compiler,
+    pub target: Interned<String>,
 }
 
 impl Step for ErrorIndex {
@@ -653,22 +654,22 @@ impl Step for ErrorIndex {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(ErrorIndex { target: run.target });
+        let target = run.target;
+        // error_index_generator depends on librustdoc. Use the compiler that
+        // is normally used to build rustdoc for other documentation so that
+        // it shares the same artifacts.
+        let compiler =
+            run.builder.compiler_for(run.builder.top_stage, run.builder.config.build, target);
+        run.builder.ensure(ErrorIndex { compiler, target });
     }
 
     /// Generates the HTML rendered error-index by running the
     /// `error_index_generator` tool.
     fn run(self, builder: &Builder<'_>) {
-        let target = self.target;
-
-        builder.info(&format!("Documenting error index ({})", target));
-        let out = builder.doc_out(target);
+        builder.info(&format!("Documenting error index ({})", self.target));
+        let out = builder.doc_out(self.target);
         t!(fs::create_dir_all(&out));
-        // error_index_generator depends on librustdoc. Use the compiler that
-        // is normally used to build rustdoc for other documentation so that
-        // it shares the same artifacts.
-        let compiler = builder.compiler_for(builder.top_stage, builder.config.build, target);
-        let mut index = tool::ErrorIndex::command(builder, compiler);
+        let mut index = tool::ErrorIndex::command(builder, self.compiler);
         index.arg("html");
         index.arg(out.join("error-index.html"));
         index.arg(crate::channel::CFG_RELEASE_NUM);

src/bootstrap/tool.rs

@@ -366,7 +366,7 @@ bootstrap_tool!(
     ExpandYamlAnchors, "src/tools/expand-yaml-anchors", "expand-yaml-anchors";
 );
 
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
 pub struct ErrorIndex {
     pub compiler: Compiler,
 }
@@ -449,7 +449,7 @@ impl Step for RemoteTestServer {
     }
 }
 
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
 pub struct Rustdoc {
     /// This should only ever be 0 or 2.
     /// We sometimes want to reference the "bootstrap" rustdoc, which is why this option is here.