Compile rustdoc on-demand

src/Cargo.toml

@@ -16,6 +16,7 @@ members = [
   "tools/remote-test-server",
   "tools/rust-installer",
   "tools/cargo",
+  "tools/rustdoc",
   "tools/rls",
   # FIXME(https://github.com/rust-lang/cargo/issues/4089): move these to exclude
   "tools/rls/test_data/borrow_error",

src/bootstrap/builder.rs

@@ -256,7 +256,7 @@ impl<'a> Builder<'a> {
                 compile::StartupObjects, tool::BuildManifest, tool::Rustbook, tool::ErrorIndex,
                 tool::UnstableBookGen, tool::Tidy, tool::Linkchecker, tool::CargoTest,
                 tool::Compiletest, tool::RemoteTestServer, tool::RemoteTestClient,
-                tool::RustInstaller, tool::Cargo, tool::Rls),
+                tool::RustInstaller, tool::Cargo, tool::Rls, tool::Rustdoc),
             Kind::Test => describe!(check::Tidy, check::Bootstrap, check::DefaultCompiletest,
                 check::HostCompiletest, check::Crate, check::CrateLibrustc, check::Linkcheck,
                 check::Cargotest, check::Cargo, check::Rls, check::Docs, check::ErrorIndex,
@@ -412,12 +412,23 @@ impl<'a> Builder<'a> {
         }
     }
 
-    /// Get the `rustdoc` executable next to the specified compiler
     pub fn rustdoc(&self, compiler: Compiler) -> PathBuf {
-        let mut rustdoc = self.rustc(compiler);
-        rustdoc.pop();
-        rustdoc.push(exe("rustdoc", &compiler.host));
-        rustdoc
+        self.ensure(tool::Rustdoc { target_compiler: compiler })
+    }
+
+    pub fn rustdoc_cmd(&self, compiler: Compiler) -> Command {
+        let mut cmd = Command::new(&self.out.join("bootstrap/debug/rustdoc"));
+        cmd
+            .env("RUSTC_STAGE", compiler.stage.to_string())
+            .env("RUSTC_SYSROOT", if compiler.is_snapshot(&self.build) {
+                INTERNER.intern_path(self.build.rustc_snapshot_libdir())
+            } else {
+                self.sysroot(compiler)
+            })
+            .env("RUSTC_LIBDIR", self.sysroot_libdir(compiler, self.build.build))
+            .env("CFG_RELEASE_CHANNEL", &self.build.config.channel)
+            .env("RUSTDOC_REAL", self.rustdoc(compiler));
+        cmd
     }
 
     /// Prepares an invocation of `cargo` to be run.
@@ -469,7 +480,11 @@ impl<'a> Builder<'a> {
              .env("RUSTC_LIBDIR", self.rustc_libdir(compiler))
              .env("RUSTC_RPATH", self.config.rust_rpath.to_string())
              .env("RUSTDOC", self.out.join("bootstrap/debug/rustdoc"))
-             .env("RUSTDOC_REAL", self.rustdoc(compiler))
+             .env("RUSTDOC_REAL", if cmd == "doc" || cmd == "test" {
+                 self.rustdoc(compiler)
+             } else {
+                 PathBuf::from("/path/to/nowhere/rustdoc/not/required")
+             })
              .env("RUSTC_FLAGS", self.rustc_flags(target).join(" "));
 
         if mode != Mode::Tool {
@@ -560,6 +575,9 @@ impl<'a> Builder<'a> {
         // FIXME: should update code to not require this env var
         cargo.env("CFG_COMPILER_HOST_TRIPLE", target);
 
+        // Set this for all builds to make sure doc builds also get it.
+        cargo.env("CFG_RELEASE_CHANNEL", &self.build.config.channel);
+
         if self.is_verbose() {
             cargo.arg("-v");
         }

src/bootstrap/check.rs

@@ -119,7 +119,7 @@ impl Step for Linkcheck {
     }
 
     fn make_run(run: RunConfig) {
-        run.builder.ensure(Linkcheck { host: run.host });
+        run.builder.ensure(Linkcheck { host: run.target });
     }
 }
 
@@ -140,7 +140,7 @@ impl Step for Cargotest {
     fn make_run(run: RunConfig) {
         run.builder.ensure(Cargotest {
             stage: run.builder.top_stage,
-            host: run.host,
+            host: run.target,
         });
     }
 
@@ -194,7 +194,7 @@ impl Step for Cargo {
         let build = builder.build;
         let compiler = builder.compiler(self.stage, self.host);
 
-        builder.ensure(tool::Cargo { stage: self.stage, target: self.host });
+        builder.ensure(tool::Cargo { compiler, target: self.host });
         let mut cargo = builder.cargo(compiler, Mode::Tool, self.host, "test");
         cargo.arg("--manifest-path").arg(build.src.join("src/tools/cargo/Cargo.toml"));
         if !build.fail_fast {
@@ -240,7 +240,7 @@ impl Step for Rls {
         let host = self.host;
         let compiler = builder.compiler(stage, host);
 
-        builder.ensure(tool::Rls { stage: self.stage, target: self.host });
+        builder.ensure(tool::Rls { compiler, target: self.host });
         let mut cargo = builder.cargo(compiler, Mode::Tool, host, "test");
         cargo.arg("--manifest-path").arg(build.src.join("src/tools/rls/Cargo.toml"));
 
@@ -562,7 +562,12 @@ impl Step for Compiletest {
         cmd.arg("--compile-lib-path").arg(builder.rustc_libdir(compiler));
         cmd.arg("--run-lib-path").arg(builder.sysroot_libdir(compiler, target));
         cmd.arg("--rustc-path").arg(builder.rustc(compiler));
-        cmd.arg("--rustdoc-path").arg(builder.rustdoc(compiler));
+
+        // Avoid depending on rustdoc when we don't need it.
+        if mode == "rustdoc" || mode == "run-make" {
+            cmd.arg("--rustdoc-path").arg(builder.rustdoc(compiler));
+        }
+
         cmd.arg("--src-base").arg(build.src.join("src/test").join(suite));
         cmd.arg("--build-base").arg(testdir(build, compiler.host).join(suite));
         cmd.arg("--stage-id").arg(format!("stage{}-{}", compiler.stage, target));
@@ -809,8 +814,7 @@ fn markdown_test(builder: &Builder, compiler: Compiler, markdown: &Path) {
     }
 
     println!("doc tests for: {}", markdown.display());
-    let mut cmd = Command::new(builder.rustdoc(compiler));
-    builder.add_rustc_lib_path(compiler, &mut cmd);
+    let mut cmd = builder.rustdoc_cmd(compiler);
     build.add_rust_test_threads(&mut cmd);
     cmd.arg("--test");
     cmd.arg(markdown);
@@ -1165,7 +1169,7 @@ impl Step for RemoteCopyLibs {
         println!("REMOTE copy libs to emulator ({})", target);
         t!(fs::create_dir_all(build.out.join("tmp")));
 
-        let server = builder.ensure(tool::RemoteTestServer { stage: compiler.stage, target });
+        let server = builder.ensure(tool::RemoteTestServer { compiler, target });
 
         // Spawn the emulator and wait for it to come online
         let tool = builder.tool_exe(Tool::RemoteTestClient);

src/bootstrap/compile.rs

@@ -719,15 +719,6 @@ impl Step for Assemble {
         let _ = fs::remove_file(&compiler);
         copy(&rustc, &compiler);
 
-        // See if rustdoc exists to link it into place
-        let rustdoc = exe("rustdoc", &*host);
-        let rustdoc_src = out_dir.join(&rustdoc);
-        let rustdoc_dst = bindir.join(&rustdoc);
-        if fs::metadata(&rustdoc_src).is_ok() {
-            let _ = fs::remove_file(&rustdoc_dst);
-            copy(&rustdoc_src, &rustdoc_dst);
-        }
-
         target_compiler
     }
 }

src/bootstrap/dist.rs

@@ -413,6 +413,9 @@ impl Step for Rustc {
             t!(fs::create_dir_all(image.join("bin")));
             cp_r(&src.join("bin"), &image.join("bin"));
 
+            install(&builder.ensure(tool::Rustdoc { target_compiler: compiler }),
+                &image.join("bin"), 0o755);
+
             // Copy runtime DLLs needed by the compiler
             if libdir != "bin" {
                 for entry in t!(src.join(libdir).read_dir()).map(|e| t!(e)) {
@@ -963,7 +966,10 @@ impl Step for Cargo {
         // Prepare the image directory
         t!(fs::create_dir_all(image.join("share/zsh/site-functions")));
         t!(fs::create_dir_all(image.join("etc/bash_completion.d")));
-        let cargo = builder.ensure(tool::Cargo { stage, target });
+        let cargo = builder.ensure(tool::Cargo {
+            compiler: builder.compiler(stage, build.build),
+            target
+        });
         install(&cargo, &image.join("bin"), 0o755);
         for man in t!(etc.join("man").read_dir()) {
             let man = t!(man);
@@ -1046,7 +1052,10 @@ impl Step for Rls {
         t!(fs::create_dir_all(&image));
 
         // Prepare the image directory
-        let rls = builder.ensure(tool::Rls { stage, target });
+        let rls = builder.ensure(tool::Rls {
+            compiler: builder.compiler(stage, build.build),
+            target
+        });
         install(&rls, &image.join("bin"), 0o755);
         let doc = image.join("share/doc/rls");
         install(&src.join("README.md"), &doc, 0o644);