src/bootstrap/tool.rs

   1 use std::collections::HashSet;
   2 use std::env;
   3 use std::fs;
   4 use std::path::PathBuf;
   5 use std::process::{exit, Command};
   6
   7 use build_helper::t;
   8
   9 use crate::builder::{Builder, Cargo as CargoCommand, RunConfig, ShouldRun, Step};
  10 use crate::cache::Interned;
  11 use crate::channel;
  12 use crate::channel::GitInfo;
  13 use crate::compile;
  14 use crate::toolstate::ToolState;
  15 use crate::util::{add_lib_path, exe, CiEnv};
  16 use crate::Compiler;
  17 use crate::Mode;
  18
  19 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
  20 pub enum SourceType {
  21     InTree,
  22     Submodule,
  23 }
  24
  25 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
  26 struct ToolBuild {
  27     compiler: Compiler,
  28     target: Interned<String>,
  29     tool: &'static str,
  30     path: &'static str,
  31     mode: Mode,
  32     is_optional_tool: bool,
  33     source_type: SourceType,
  34     extra_features: Vec<String>,
  35 }
  36
  37 impl Step for ToolBuild {
  38     type Output = Option<PathBuf>;
  39
  40     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
  41         run.never()
  42     }
  43
  44     /// Builds a tool in `src/tools`
  45     ///
  46     /// This will build the specified tool with the specified `host` compiler in
  47     /// `stage` into the normal cargo output directory.
  48     fn run(self, builder: &Builder<'_>) -> Option<PathBuf> {
  49         let compiler = self.compiler;
  50         let target = self.target;
  51         let tool = self.tool;
  52         let path = self.path;
  53         let is_optional_tool = self.is_optional_tool;
  54
  55         match self.mode {
  56             Mode::ToolRustc => builder.ensure(compile::Rustc { compiler, target }),
  57             Mode::ToolStd => builder.ensure(compile::Std { compiler, target }),
  58             Mode::ToolBootstrap => {} // uses downloaded stage0 compiler libs
  59             _ => panic!("unexpected Mode for tool build"),
  60         }
  61
  62         let cargo = prepare_tool_cargo(
  63             builder,
  64             compiler,
  65             self.mode,
  66             target,
  67             "build",
  68             path,
  69             self.source_type,
  70             &self.extra_features,
  71         );
  72
  73         builder.info(&format!("Building stage{} tool {} ({})", compiler.stage, tool, target));
  74         let mut duplicates = Vec::new();
  75         let is_expected = compile::stream_cargo(builder, cargo, vec![], &mut |msg| {
  76             // Only care about big things like the RLS/Cargo for now
  77             match tool {
  78                 "rls" | "cargo" | "clippy-driver" | "miri" | "rustfmt" => {}
  79
  80                 _ => return,
  81             }
  82             let (id, features, filenames) = match msg {
  83                 compile::CargoMessage::CompilerArtifact {
  84                     package_id,
  85                     features,
  86                     filenames,
  87                     target: _,
  88                 } => (package_id, features, filenames),
  89                 _ => return,
  90             };
  91             let features = features.iter().map(|s| s.to_string()).collect::<Vec<_>>();
  92
  93             for path in filenames {
  94                 let val = (tool, PathBuf::from(&*path), features.clone());
  95                 // we're only interested in deduplicating rlibs for now
  96                 if val.1.extension().and_then(|s| s.to_str()) != Some("rlib") {
  97                     continue;
  98                 }
  99
 100                 // Don't worry about compiles that turn out to be host
 101                 // dependencies or build scripts. To skip these we look for
 102                 // anything that goes in `.../release/deps` but *doesn't* go in
 103                 // `$target/release/deps`. This ensure that outputs in
 104                 // `$target/release` are still considered candidates for
 105                 // deduplication.
 106                 if let Some(parent) = val.1.parent() {
 107                     if parent.ends_with("release/deps") {
 108                         let maybe_target = parent
 109                             .parent()
 110                             .and_then(|p| p.parent())
 111                             .and_then(|p| p.file_name())
 112                             .and_then(|p| p.to_str())
 113                             .unwrap();
 114                         if maybe_target != &*target {
 115                             continue;
 116                         }
 117                     }
 118                 }
 119
 120                 // Record that we've built an artifact for `id`, and if one was
 121                 // already listed then we need to see if we reused the same
 122                 // artifact or produced a duplicate.
 123                 let mut artifacts = builder.tool_artifacts.borrow_mut();
 124                 let prev_artifacts = artifacts.entry(target).or_default();
 125                 let prev = match prev_artifacts.get(&*id) {
 126                     Some(prev) => prev,
 127                     None => {
 128                         prev_artifacts.insert(id.to_string(), val);
 129                         continue;
 130                     }
 131                 };
 132                 if prev.1 == val.1 {
 133                     return; // same path, same artifact
 134                 }
 135
 136                 // If the paths are different and one of them *isn't* inside of
 137                 // `release/deps`, then it means it's probably in
 138                 // `$target/release`, or it's some final artifact like
 139                 // `libcargo.rlib`. In these situations Cargo probably just
 140                 // copied it up from `$target/release/deps/libcargo-xxxx.rlib`,
 141                 // so if the features are equal we can just skip it.
 142                 let prev_no_hash = prev.1.parent().unwrap().ends_with("release/deps");
 143                 let val_no_hash = val.1.parent().unwrap().ends_with("release/deps");
 144                 if prev.2 == val.2 || !prev_no_hash || !val_no_hash {
 145                     return;
 146                 }
 147
 148                 // ... and otherwise this looks like we duplicated some sort of
 149                 // compilation, so record it to generate an error later.
 150                 duplicates.push((id.to_string(), val, prev.clone()));
 151             }
 152         });
 153
 154         if is_expected && !duplicates.is_empty() {
 155             println!(
 156                 "duplicate artifacts found when compiling a tool, this \
 157                       typically means that something was recompiled because \
 158                       a transitive dependency has different features activated \
 159                       than in a previous build:\n"
 160             );
 161             println!(
 162                 "the following dependencies are duplicated although they \
 163                       have the same features enabled:"
 164             );
 165             for (id, cur, prev) in duplicates.drain_filter(|(_, cur, prev)| cur.2 == prev.2) {
 166                 println!("  {}", id);
 167                 // same features
 168                 println!("    `{}` ({:?})\n    `{}` ({:?})", cur.0, cur.1, prev.0, prev.1);
 169             }
 170             println!("the following dependencies have different features:");
 171             for (id, cur, prev) in duplicates {
 172                 println!("  {}", id);
 173                 let cur_features: HashSet<_> = cur.2.into_iter().collect();
 174                 let prev_features: HashSet<_> = prev.2.into_iter().collect();
 175                 println!(
 176                     "    `{}` additionally enabled features {:?} at {:?}",
 177                     cur.0,
 178                     &cur_features - &prev_features,
 179                     cur.1
 180                 );
 181                 println!(
 182                     "    `{}` additionally enabled features {:?} at {:?}",
 183                     prev.0,
 184                     &prev_features - &cur_features,
 185                     prev.1
 186                 );
 187             }
 188             println!();
 189             println!(
 190                 "to fix this you will probably want to edit the local \
 191                       src/tools/rustc-workspace-hack/Cargo.toml crate, as \
 192                       that will update the dependency graph to ensure that \
 193                       these crates all share the same feature set"
 194             );
 195             panic!("tools should not compile multiple copies of the same crate");
 196         }
 197
 198         builder.save_toolstate(
 199             tool,
 200             if is_expected { ToolState::TestFail } else { ToolState::BuildFail },
 201         );
 202
 203         if !is_expected {
 204             if !is_optional_tool {
 205                 exit(1);
 206             } else {
 207                 None
 208             }
 209         } else {
 210             let cargo_out =
 211                 builder.cargo_out(compiler, self.mode, target).join(exe(tool, &compiler.host));
 212             let bin = builder.tools_dir(compiler).join(exe(tool, &compiler.host));
 213             builder.copy(&cargo_out, &bin);
 214             Some(bin)
 215         }
 216     }
 217 }
 218
 219 pub fn prepare_tool_cargo(
 220     builder: &Builder<'_>,
 221     compiler: Compiler,
 222     mode: Mode,
 223     target: Interned<String>,
 224     command: &'static str,
 225     path: &'static str,
 226     source_type: SourceType,
 227     extra_features: &[String],
 228 ) -> CargoCommand {
 229     let mut cargo = builder.cargo(compiler, mode, target, command);
 230     let dir = builder.src.join(path);
 231     cargo.arg("--manifest-path").arg(dir.join("Cargo.toml"));
 232
 233     if source_type == SourceType::Submodule {
 234         cargo.env("RUSTC_EXTERNAL_TOOL", "1");
 235     }
 236
 237     let mut features = extra_features.iter().cloned().collect::<Vec<_>>();
 238     if builder.build.config.cargo_native_static {
 239         if path.ends_with("cargo")
 240             || path.ends_with("rls")
 241             || path.ends_with("clippy")
 242             || path.ends_with("miri")
 243             || path.ends_with("rustbook")
 244             || path.ends_with("rustfmt")
 245         {
 246             cargo.env("LIBZ_SYS_STATIC", "1");
 247             features.push("rustc-workspace-hack/all-static".to_string());
 248         }
 249     }
 250
 251     // if tools are using lzma we want to force the build script to build its
 252     // own copy
 253     cargo.env("LZMA_API_STATIC", "1");
 254
 255     cargo.env("CFG_RELEASE_CHANNEL", &builder.config.channel);
 256     cargo.env("CFG_VERSION", builder.rust_version());
 257     cargo.env("CFG_RELEASE_NUM", channel::CFG_RELEASE_NUM);
 258
 259     let info = GitInfo::new(builder.config.ignore_git, &dir);
 260     if let Some(sha) = info.sha() {
 261         cargo.env("CFG_COMMIT_HASH", sha);
 262     }
 263     if let Some(sha_short) = info.sha_short() {
 264         cargo.env("CFG_SHORT_COMMIT_HASH", sha_short);
 265     }
 266     if let Some(date) = info.commit_date() {
 267         cargo.env("CFG_COMMIT_DATE", date);
 268     }
 269     if !features.is_empty() {
 270         cargo.arg("--features").arg(&features.join(", "));
 271     }
 272     cargo
 273 }
 274
 275 fn rustbook_features() -> Vec<String> {
 276     let mut features = Vec::new();
 277
 278     // Due to CI budged and risk of spurious failures we want to limit jobs running this check.
 279     // At same time local builds should run it regardless of the platform.
 280     // `CiEnv::None` means it's local build and `CHECK_LINKS` is defined in x86_64-gnu-tools to
 281     // explicitly enable it on single job
 282     if CiEnv::current() == CiEnv::None || env::var("CHECK_LINKS").is_ok() {
 283         features.push("linkcheck".to_string());
 284     }
 285
 286     features
 287 }
 288
 289 macro_rules! bootstrap_tool {
 290     ($(
 291         $name:ident, $path:expr, $tool_name:expr
 292         $(,llvm_tools = $llvm:expr)*
 293         $(,is_external_tool = $external:expr)*
 294         $(,features = $features:expr)*
 295         ;
 296     )+) => {
 297         #[derive(Copy, PartialEq, Eq, Clone)]
 298         pub enum Tool {
 299             $(
 300                 $name,
 301             )+
 302         }
 303
 304         impl Tool {
 305             /// Whether this tool requires LLVM to run
 306             pub fn uses_llvm_tools(&self) -> bool {
 307                 match self {
 308                     $(Tool::$name => false $(|| $llvm)*,)+
 309                 }
 310             }
 311         }
 312
 313         impl<'a> Builder<'a> {
 314             pub fn tool_exe(&self, tool: Tool) -> PathBuf {
 315                 match tool {
 316                     $(Tool::$name =>
 317                         self.ensure($name {
 318                             compiler: self.compiler(0, self.config.build),
 319                             target: self.config.build,
 320                         }),
 321                     )+
 322                 }
 323             }
 324         }
 325
 326         $(
 327             #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 328         pub struct $name {
 329             pub compiler: Compiler,
 330             pub target: Interned<String>,
 331         }
 332
 333         impl Step for $name {
 334             type Output = PathBuf;
 335
 336             fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
 337                 run.path($path)
 338             }
 339
 340             fn make_run(run: RunConfig<'_>) {
 341                 run.builder.ensure($name {
 342                     // snapshot compiler
 343                     compiler: run.builder.compiler(0, run.builder.config.build),
 344                     target: run.target,
 345                 });
 346             }
 347
 348             fn run(self, builder: &Builder<'_>) -> PathBuf {
 349                 builder.ensure(ToolBuild {
 350                     compiler: self.compiler,
 351                     target: self.target,
 352                     tool: $tool_name,
 353                     mode: Mode::ToolBootstrap,
 354                     path: $path,
 355                     is_optional_tool: false,
 356                     source_type: if false $(|| $external)* {
 357                         SourceType::Submodule
 358                     } else {
 359                         SourceType::InTree
 360                     },
 361                     extra_features: {
 362                         // FIXME(#60643): avoid this lint by using `_`
 363                         let mut _tmp = Vec::new();
 364                         $(_tmp.extend($features);)*
 365                         _tmp
 366                     },
 367                 }).expect("expected to build -- essential tool")
 368             }
 369         }
 370         )+
 371     }
 372 }
 373
 374 bootstrap_tool!(
 375     Rustbook, "src/tools/rustbook", "rustbook", features = rustbook_features();
 376     UnstableBookGen, "src/tools/unstable-book-gen", "unstable-book-gen";
 377     Tidy, "src/tools/tidy", "tidy";
 378     Linkchecker, "src/tools/linkchecker", "linkchecker";
 379     CargoTest, "src/tools/cargotest", "cargotest";
 380     Compiletest, "src/tools/compiletest", "compiletest", llvm_tools = true;
 381     BuildManifest, "src/tools/build-manifest", "build-manifest";
 382     RemoteTestClient, "src/tools/remote-test-client", "remote-test-client";
 383     RustInstaller, "src/tools/rust-installer", "fabricate", is_external_tool = true;
 384     RustdocTheme, "src/tools/rustdoc-themes", "rustdoc-themes";
 385 );
 386
 387 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 388 pub struct ErrorIndex {
 389     pub compiler: Compiler,
 390 }
 391
 392 impl ErrorIndex {
 393     pub fn command(builder: &Builder<'_>, compiler: Compiler) -> Command {
 394         let mut cmd = Command::new(builder.ensure(ErrorIndex { compiler }));
 395         add_lib_path(
 396             vec![PathBuf::from(&builder.sysroot_libdir(compiler, compiler.host))],
 397             &mut cmd,
 398         );
 399         cmd
 400     }
 401 }
 402
 403 impl Step for ErrorIndex {
 404     type Output = PathBuf;
 405
 406     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
 407         run.path("src/tools/error_index_generator")
 408     }
 409
 410     fn make_run(run: RunConfig<'_>) {
 411         // Compile the error-index in the same stage as rustdoc to avoid
 412         // recompiling rustdoc twice if we can.
 413         let stage = if run.builder.top_stage >= 2 { run.builder.top_stage } else { 0 };
 414         run.builder
 415             .ensure(ErrorIndex { compiler: run.builder.compiler(stage, run.builder.config.build) });
 416     }
 417
 418     fn run(self, builder: &Builder<'_>) -> PathBuf {
 419         builder
 420             .ensure(ToolBuild {
 421                 compiler: self.compiler,
 422                 target: self.compiler.host,
 423                 tool: "error_index_generator",
 424                 mode: Mode::ToolRustc,
 425                 path: "src/tools/error_index_generator",
 426                 is_optional_tool: false,
 427                 source_type: SourceType::InTree,
 428                 extra_features: Vec::new(),
 429             })
 430             .expect("expected to build -- essential tool")
 431     }
 432 }
 433
 434 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 435 pub struct RemoteTestServer {
 436     pub compiler: Compiler,
 437     pub target: Interned<String>,
 438 }
 439
 440 impl Step for RemoteTestServer {
 441     type Output = PathBuf;
 442
 443     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
 444         run.path("src/tools/remote-test-server")
 445     }
 446
 447     fn make_run(run: RunConfig<'_>) {
 448         run.builder.ensure(RemoteTestServer {
 449             compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 450             target: run.target,
 451         });
 452     }
 453
 454     fn run(self, builder: &Builder<'_>) -> PathBuf {
 455         builder
 456             .ensure(ToolBuild {
 457                 compiler: self.compiler,
 458                 target: self.target,
 459                 tool: "remote-test-server",
 460                 mode: Mode::ToolStd,
 461                 path: "src/tools/remote-test-server",
 462                 is_optional_tool: false,
 463                 source_type: SourceType::InTree,
 464                 extra_features: Vec::new(),
 465             })
 466             .expect("expected to build -- essential tool")
 467     }
 468 }
 469
 470 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 471 pub struct Rustdoc {
 472     /// This should only ever be 0 or 2.
 473     /// We sometimes want to reference the "bootstrap" rustdoc, which is why this option is here.
 474     pub compiler: Compiler,
 475 }
 476
 477 impl Step for Rustdoc {
 478     type Output = PathBuf;
 479     const DEFAULT: bool = true;
 480     const ONLY_HOSTS: bool = true;
 481
 482     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
 483         run.path("src/tools/rustdoc")
 484     }
 485
 486     fn make_run(run: RunConfig<'_>) {
 487         run.builder
 488             .ensure(Rustdoc { compiler: run.builder.compiler(run.builder.top_stage, run.host) });
 489     }
 490
 491     fn run(self, builder: &Builder<'_>) -> PathBuf {
 492         let target_compiler = self.compiler;
 493         if target_compiler.stage == 0 {
 494             if !target_compiler.is_snapshot(builder) {
 495                 panic!("rustdoc in stage 0 must be snapshot rustdoc");
 496             }
 497             return builder.initial_rustc.with_file_name(exe("rustdoc", &target_compiler.host));
 498         }
 499         let target = target_compiler.host;
 500         // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
 501         // we'd have stageN/bin/rustc and stageN/bin/rustdoc be effectively different stage
 502         // compilers, which isn't what we want. Rustdoc should be linked in the same way as the
 503         // rustc compiler it's paired with, so it must be built with the previous stage compiler.
 504         let build_compiler = builder.compiler(target_compiler.stage - 1, builder.config.build);
 505
 506         // The presence of `target_compiler` ensures that the necessary libraries (codegen backends,
 507         // compiler libraries, ...) are built. Rustdoc does not require the presence of any
 508         // libraries within sysroot_libdir (i.e., rustlib), though doctests may want it (since
 509         // they'll be linked to those libraries). As such, don't explicitly `ensure` any additional
 510         // libraries here. The intuition here is that If we've built a compiler, we should be able
 511         // to build rustdoc.
 512
 513         let cargo = prepare_tool_cargo(
 514             builder,
 515             build_compiler,
 516             Mode::ToolRustc,
 517             target,
 518             "build",
 519             "src/tools/rustdoc",
 520             SourceType::InTree,
 521             &[],
 522         );
 523
 524         builder.info(&format!(
 525             "Building rustdoc for stage{} ({})",
 526             target_compiler.stage, target_compiler.host
 527         ));
 528         builder.run(&mut cargo.into());
 529
 530         // Cargo adds a number of paths to the dylib search path on windows, which results in
 531         // the wrong rustdoc being executed. To avoid the conflicting rustdocs, we name the "tool"
 532         // rustdoc a different name.
 533         let tool_rustdoc = builder
 534             .cargo_out(build_compiler, Mode::ToolRustc, target)
 535             .join(exe("rustdoc_tool_binary", &target_compiler.host));
 536
 537         // don't create a stage0-sysroot/bin directory.
 538         if target_compiler.stage > 0 {
 539             let sysroot = builder.sysroot(target_compiler);
 540             let bindir = sysroot.join("bin");
 541             t!(fs::create_dir_all(&bindir));
 542             let bin_rustdoc = bindir.join(exe("rustdoc", &*target_compiler.host));
 543             let _ = fs::remove_file(&bin_rustdoc);
 544             builder.copy(&tool_rustdoc, &bin_rustdoc);
 545             bin_rustdoc
 546         } else {
 547             tool_rustdoc
 548         }
 549     }
 550 }
 551
 552 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 553 pub struct Cargo {
 554     pub compiler: Compiler,
 555     pub target: Interned<String>,
 556 }
 557
 558 impl Step for Cargo {
 559     type Output = PathBuf;
 560     const DEFAULT: bool = true;
 561     const ONLY_HOSTS: bool = true;
 562
 563     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
 564         let builder = run.builder;
 565         run.path("src/tools/cargo").default_condition(builder.config.extended)
 566     }
 567
 568     fn make_run(run: RunConfig<'_>) {
 569         run.builder.ensure(Cargo {
 570             compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 571             target: run.target,
 572         });
 573     }
 574
 575     fn run(self, builder: &Builder<'_>) -> PathBuf {
 576         builder
 577             .ensure(ToolBuild {
 578                 compiler: self.compiler,
 579                 target: self.target,
 580                 tool: "cargo",
 581                 mode: Mode::ToolRustc,
 582                 path: "src/tools/cargo",
 583                 is_optional_tool: false,
 584                 source_type: SourceType::Submodule,
 585                 extra_features: Vec::new(),
 586             })
 587             .expect("expected to build -- essential tool")
 588     }
 589 }
 590
 591 macro_rules! tool_extended {
 592     (($sel:ident, $builder:ident),
 593        $($name:ident,
 594        $toolstate:ident,
 595        $path:expr,
 596        $tool_name:expr,
 597        $extra_deps:block;)+) => {
 598         $(
 599             #[derive(Debug, Clone, Hash, PartialEq, Eq)]
 600         pub struct $name {
 601             pub compiler: Compiler,
 602             pub target: Interned<String>,
 603             pub extra_features: Vec<String>,
 604         }
 605
 606         impl Step for $name {
 607             type Output = Option<PathBuf>;
 608             const DEFAULT: bool = true;
 609             const ONLY_HOSTS: bool = true;
 610
 611             fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
 612                 let builder = run.builder;
 613                 run.path($path).default_condition(builder.config.extended)
 614             }
 615
 616             fn make_run(run: RunConfig<'_>) {
 617                 run.builder.ensure($name {
 618                     compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 619                     target: run.target,
 620                     extra_features: Vec::new(),
 621                 });
 622             }
 623
 624             #[allow(unused_mut)]
 625             fn run(mut $sel, $builder: &Builder<'_>) -> Option<PathBuf> {
 626                 $extra_deps
 627                 $builder.ensure(ToolBuild {
 628                     compiler: $sel.compiler,
 629                     target: $sel.target,
 630                     tool: $tool_name,
 631                     mode: Mode::ToolRustc,
 632                     path: $path,
 633                     extra_features: $sel.extra_features,
 634                     is_optional_tool: true,
 635                     source_type: SourceType::Submodule,
 636                 })
 637             }
 638         }
 639         )+
 640     }
 641 }
 642
 643 tool_extended!((self, builder),
 644     Cargofmt, rustfmt, "src/tools/rustfmt", "cargo-fmt", {};
 645     CargoClippy, clippy, "src/tools/clippy", "cargo-clippy", {};
 646     Clippy, clippy, "src/tools/clippy", "clippy-driver", {};
 647     Miri, miri, "src/tools/miri", "miri", {};
 648     CargoMiri, miri, "src/tools/miri", "cargo-miri", {};
 649     Rls, rls, "src/tools/rls", "rls", {
 650         let clippy = builder.ensure(Clippy {
 651             compiler: self.compiler,
 652             target: self.target,
 653             extra_features: Vec::new(),
 654         });
 655         if clippy.is_some() {
 656             self.extra_features.push("clippy".to_owned());
 657         }
 658     };
 659     Rustfmt, rustfmt, "src/tools/rustfmt", "rustfmt", {};
 660 );
 661
 662 impl<'a> Builder<'a> {
 663     /// Gets a `Command` which is ready to run `tool` in `stage` built for
 664     /// `host`.
 665     pub fn tool_cmd(&self, tool: Tool) -> Command {
 666         let mut cmd = Command::new(self.tool_exe(tool));
 667         let compiler = self.compiler(0, self.config.build);
 668         let host = &compiler.host;
 669         // Prepares the `cmd` provided to be able to run the `compiler` provided.
 670         //
 671         // Notably this munges the dynamic library lookup path to point to the
 672         // right location to run `compiler`.
 673         let mut lib_paths: Vec<PathBuf> = vec![
 674             self.build.rustc_snapshot_libdir(),
 675             self.cargo_out(compiler, Mode::ToolBootstrap, *host).join("deps"),
 676         ];
 677
 678         // On MSVC a tool may invoke a C compiler (e.g., compiletest in run-make
 679         // mode) and that C compiler may need some extra PATH modification. Do
 680         // so here.
 681         if compiler.host.contains("msvc") {
 682             let curpaths = env::var_os("PATH").unwrap_or_default();
 683             let curpaths = env::split_paths(&curpaths).collect::<Vec<_>>();
 684             for &(ref k, ref v) in self.cc[&compiler.host].env() {
 685                 if k != "PATH" {
 686                     continue;
 687                 }
 688                 for path in env::split_paths(v) {
 689                     if !curpaths.contains(&path) {
 690                         lib_paths.push(path);
 691                     }
 692                 }
 693             }
 694         }
 695
 696         add_lib_path(lib_paths, &mut cmd);
 697         cmd
 698     }
 699 }