Build rustdoc on-demand.

Rustdoc is no longer compiled in every stage, alongside rustc, instead
it is only compiled when requested, and generally only for the last
stage.

14 files changed, 106 insertions, 67 deletions

diff --git a/src/Cargo.lock b/src/Cargo.lock
index 1df8bcf74cd..e193cc612c5 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -439,6 +439,9 @@ dependencies = [
 [[package]]
 name = "error_index_generator"
 version = "0.0.0"
+dependencies = [
+ "rustdoc 0.0.0",
+]
 
 [[package]]
 name = "filetime"
@@ -1222,7 +1225,6 @@ version = "0.0.0"
 dependencies = [
  "rustc_back 0.0.0",
  "rustc_driver 0.0.0",
- "rustdoc 0.0.0",
 ]
 
 [[package]]
@@ -1560,25 +1562,18 @@ dependencies = [
 name = "rustdoc"
 version = "0.0.0"
 dependencies = [
- "arena 0.0.0",
  "build_helper 0.1.0",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "gcc 0.3.51 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "pulldown-cmark 0.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc 0.0.0",
- "rustc_back 0.0.0",
- "rustc_data_structures 0.0.0",
- "rustc_driver 0.0.0",
- "rustc_errors 0.0.0",
- "rustc_lint 0.0.0",
- "rustc_metadata 0.0.0",
- "rustc_resolve 0.0.0",
- "rustc_trans 0.0.0",
- "rustc_typeck 0.0.0",
- "serialize 0.0.0",
- "syntax 0.0.0",
- "syntax_pos 0.0.0",
+]
+
+[[package]]
+name = "rustdoc-tool"
+version = "0.0.0"
+dependencies = [
+ "rustdoc 0.0.0",
 ]
 
 [[package]]
diff --git a/src/Cargo.toml b/src/Cargo.toml
index 6e81ec67260..4b84272df98 100644
--- a/src/Cargo.toml
+++ b/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",
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 7be391e5420..04730081e58 100644
--- a/src/bootstrap/builder.rs
+++ b/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 +412,22 @@ 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("RUSTDOC_REAL", self.rustdoc(compiler));
+        cmd
     }
 
     /// Prepares an invocation of `cargo` to be run.
@@ -469,7 +479,11 @@ 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 {
diff --git a/src/bootstrap/check.rs b/src/bootstrap/check.rs
index 07b027ce5ab..3b3b062b151 100644
--- a/src/bootstrap/check.rs
+++ b/src/bootstrap/check.rs
@@ -809,8 +809,7 @@ 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);
diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index 2e808c65684..92a42b59212 100644
--- a/src/bootstrap/compile.rs
+++ b/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
     }
 }
diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index e5ededbfec7..c322d75dd5b 100644
--- a/src/bootstrap/dist.rs
+++ b/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)) {
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index 249ed2a2223..88612db0d3a 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -21,7 +21,6 @@ use std::fs::{self, File};
 use std::io::prelude::*;
 use std::io;
 use std::path::{PathBuf, Path};
-use std::process::Command;
 
 use Mode;
 use build_helper::up_to_date;
@@ -242,12 +241,8 @@ fn invoke_rustdoc(builder: &Builder, target: Interned<String>, markdown: &str) {
     let build = builder.build;
     let out = build.doc_out(target);
 
-    let compiler = builder.compiler(0, build.build);
-
     let path = build.src.join("src/doc").join(markdown);
 
-    let rustdoc = builder.rustdoc(compiler);
-
     let favicon = build.src.join("src/doc/favicon.inc");
     let footer = build.src.join("src/doc/footer.inc");
 
@@ -263,9 +258,7 @@ fn invoke_rustdoc(builder: &Builder, target: Interned<String>, markdown: &str) {
         t!(t!(File::create(&version_info)).write_all(info.as_bytes()));
     }
 
-    let mut cmd = Command::new(&rustdoc);
-
-    builder.add_rustc_lib_path(compiler, &mut cmd);
+    let mut cmd = builder.rustdoc_cmd(builder.compiler(0, build.build));
 
     let out = out.join("book");
 
@@ -357,8 +350,7 @@ impl Step for Standalone {
                 continue
             }
 
-            let mut cmd = Command::new(&rustdoc);
-            builder.add_rustc_lib_path(compiler, &mut cmd);
+            let mut cmd = builder.rustdoc_cmd(compiler);
             cmd.arg("--html-after-content").arg(&footer)
                .arg("--html-before-content").arg(&version_info)
                .arg("--html-in-header").arg(&favicon)
diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index f78792fc9b5..cbb312e2e4c 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use std::fs;
 use std::env;
 use std::path::PathBuf;
 use std::process::Command;
@@ -15,7 +16,7 @@ use std::process::Command;
 use Mode;
 use Compiler;
 use builder::{Step, RunConfig, ShouldRun, Builder};
-use util::{exe, add_lib_path};
+use util::{copy, exe, add_lib_path};
 use compile::{self, libtest_stamp, libstd_stamp, librustc_stamp};
 use native;
 use channel::GitInfo;
@@ -224,6 +225,56 @@ impl Step for RemoteTestServer {
 }
 
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+pub struct Rustdoc {
+    pub target_compiler: Compiler,
+}
+
+impl Step for Rustdoc {
+    type Output = PathBuf;
+    const DEFAULT: bool = true;
+    const ONLY_HOSTS: bool = true;
+
+    fn should_run(run: ShouldRun) -> ShouldRun {
+        run.path("src/tools/rustdoc")
+    }
+
+    fn make_run(run: RunConfig) {
+        run.builder.ensure(Rustdoc {
+            target_compiler: run.builder.compiler(run.builder.top_stage, run.host),
+        });
+    }
+
+    fn run(self, builder: &Builder) -> PathBuf {
+        let target_compiler = self.target_compiler;
+        let build_compiler = if target_compiler.stage == 0 {
+            target_compiler
+        } else {
+            builder.compiler(target_compiler.stage - 1, target_compiler.host)
+        };
+
+        let tool_rustdoc = builder.ensure(ToolBuild {
+            compiler: build_compiler,
+            target: build_compiler.host,
+            tool: "rustdoc",
+            mode: Mode::Librustc,
+        });
+
+        // don't create a stage0-sysroot/bin directory.
+        if target_compiler.stage > 0 {
+            let sysroot = builder.sysroot(target_compiler);
+            let bindir = sysroot.join("bin");
+            t!(fs::create_dir_all(&bindir));
+            let bin_rustdoc = bindir.join(exe("rustdoc", &*target_compiler.host));
+            let _ = fs::remove_file(&bin_rustdoc);
+            copy(&tool_rustdoc, &bin_rustdoc);
+            bin_rustdoc
+        } else {
+            tool_rustdoc
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct Cargo {
     pub compiler: Compiler,
     pub target: Interned<String>,
diff --git a/src/librustdoc/Cargo.toml b/src/librustdoc/Cargo.toml
index 68f03d32e83..f9400e68a16 100644
--- a/src/librustdoc/Cargo.toml
+++ b/src/librustdoc/Cargo.toml
@@ -7,25 +7,10 @@ build = "build.rs"
 [lib]
 name = "rustdoc"
 path = "lib.rs"
-crate-type = ["dylib"]
 
 [dependencies]
-arena = { path = "../libarena" }
 env_logger = { version = "0.4", default-features = false }
 log = "0.3"
-rustc = { path = "../librustc" }
-rustc_back = { path = "../librustc_back" }
-rustc_data_structures = { path = "../librustc_data_structures" }
-rustc_driver = { path = "../librustc_driver" }
-rustc_errors = { path = "../librustc_errors" }
-rustc_lint = { path = "../librustc_lint" }
-rustc_metadata = { path = "../librustc_metadata" }
-rustc_resolve = { path = "../librustc_resolve" }
-rustc_typeck = { path = "../librustc_typeck" }
-rustc_trans = { path = "../librustc_trans" }
-serialize = { path = "../libserialize" }
-syntax = { path = "../libsyntax" }
-syntax_pos = { path = "../libsyntax_pos" }
 pulldown-cmark = { version = "0.0.14", default-features = false }
 
 [build-dependencies]
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 6c092d01a01..64240d26894 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -17,6 +17,7 @@
        html_playground_url = "https://play.rust-lang.org/")]
 #![deny(warnings)]
 
+#![feature(rustc_private)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(libc)]
diff --git a/src/rustc/Cargo.toml b/src/rustc/Cargo.toml
index dce1a0a8ec8..4452f4a2f44 100644
--- a/src/rustc/Cargo.toml
+++ b/src/rustc/Cargo.toml
@@ -7,16 +7,11 @@ version = "0.0.0"
 name = "rustc"
 path = "rustc.rs"
 
-[[bin]]
-name = "rustdoc"
-path = "rustdoc.rs"
-
 # All optional dependencies so the features passed to this Cargo.toml select
 # what should actually be built.
 [dependencies]
 rustc_back = { path = "../librustc_back" }
 rustc_driver = { path = "../librustc_driver" }
-rustdoc = { path = "../librustdoc" }
 
 [features]
 jemalloc = ["rustc_back/jemalloc"]
diff --git a/src/tools/error_index_generator/Cargo.toml b/src/tools/error_index_generator/Cargo.toml
index 5c5ca273e9c..7f8783c9d89 100644
--- a/src/tools/error_index_generator/Cargo.toml
+++ b/src/tools/error_index_generator/Cargo.toml
@@ -3,6 +3,9 @@ authors = ["The Rust Project Developers"]
 name = "error_index_generator"
 version = "0.0.0"
 
+[dependencies]
+rustdoc = { path = "../../librustdoc" }
+
 [[bin]]
 name = "error_index_generator"
 path = "main.rs"
diff --git a/src/tools/rustdoc/Cargo.toml b/src/tools/rustdoc/Cargo.toml
new file mode 100644
index 00000000000..b6edb76d7f9
--- /dev/null
+++ b/src/tools/rustdoc/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "rustdoc-tool"
+version = "0.0.0"
+authors = ["The Rust Project Developers"]
+
+[[bin]]
+name = "rustdoc"
+path = "main.rs"
+
+[dependencies]
+rustdoc = { path = "../../librustdoc" }
diff --git a/src/rustc/rustdoc.rs b/src/tools/rustdoc/main.rs
index a4f43c42623..9c37e249ba8 100644
--- a/src/rustc/rustdoc.rs
+++ b/src/tools/rustdoc/main.rs
@@ -1,4 +1,4 @@
-// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(rustc_private)]
-
 extern crate rustdoc;
 
 fn main() { rustdoc::main() }