src/bootstrap/tool.rs

   1 use std::fs;
   2 use std::env;
   3 use std::path::PathBuf;
   4 use std::process::{Command, exit};
   5 use std::collections::HashSet;
   6
   7 use crate::Mode;
   8 use crate::Compiler;
   9 use crate::builder::{Step, RunConfig, ShouldRun, Builder};
  10 use crate::util::{exe, add_lib_path};
  11 use crate::compile;
  12 use crate::native;
  13 use crate::channel::GitInfo;
  14 use crate::channel;
  15 use crate::cache::Interned;
  16 use crate::toolstate::ToolState;
  17
  18 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
  19 pub enum SourceType {
  20     InTree,
  21     Submodule,
  22 }
  23
  24 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
  25 struct ToolBuild {
  26     compiler: Compiler,
  27     target: Interned<String>,
  28     tool: &'static str,
  29     path: &'static str,
  30     mode: Mode,
  31     is_optional_tool: bool,
  32     source_type: SourceType,
  33     extra_features: Vec<String>,
  34 }
  35
  36 impl Step for ToolBuild {
  37     type Output = Option<PathBuf>;
  38
  39     fn should_run(run: ShouldRun) -> ShouldRun {
  40         run.never()
  41     }
  42
  43     /// Builds a tool in `src/tools`
  44     ///
  45     /// This will build the specified tool with the specified `host` compiler in
  46     /// `stage` into the normal cargo output directory.
  47     fn run(self, builder: &Builder) -> Option<PathBuf> {
  48         let compiler = self.compiler;
  49         let target = self.target;
  50         let tool = self.tool;
  51         let path = self.path;
  52         let is_optional_tool = self.is_optional_tool;
  53
  54         match self.mode {
  55             Mode::ToolRustc => {
  56                 builder.ensure(compile::Rustc { compiler, target })
  57             }
  58             Mode::ToolStd => {
  59                 builder.ensure(compile::Std { compiler, target })
  60             }
  61             Mode::ToolBootstrap => {} // uses downloaded stage0 compiler libs
  62             _ => panic!("unexpected Mode for tool build")
  63         }
  64
  65         let mut cargo = prepare_tool_cargo(
  66             builder,
  67             compiler,
  68             self.mode,
  69             target,
  70             "build",
  71             path,
  72             self.source_type,
  73             &self.extra_features,
  74         );
  75
  76         let _folder = builder.fold_output(|| format!("stage{}-{}", compiler.stage, tool));
  77         builder.info(&format!("Building stage{} tool {} ({})", compiler.stage, tool, target));
  78         let mut duplicates = Vec::new();
  79         let is_expected = compile::stream_cargo(builder, &mut cargo, &mut |msg| {
  80             // Only care about big things like the RLS/Cargo for now
  81             match tool {
  82                 | "rls"
  83                 | "cargo"
  84                 | "clippy-driver"
  85                 | "miri"
  86                 => {}
  87
  88                 _ => return,
  89             }
  90             let (id, features, filenames) = match msg {
  91                 compile::CargoMessage::CompilerArtifact {
  92                     package_id,
  93                     features,
  94                     filenames
  95                 } => {
  96                     (package_id, features, filenames)
  97                 }
  98                 _ => return,
  99             };
 100             let features = features.iter().map(|s| s.to_string()).collect::<Vec<_>>();
 101
 102             for path in filenames {
 103                 let val = (tool, PathBuf::from(&*path), features.clone());
 104                 // we're only interested in deduplicating rlibs for now
 105                 if val.1.extension().and_then(|s| s.to_str()) != Some("rlib") {
 106                     continue
 107                 }
 108
 109                 // Don't worry about libs that turn out to be host dependencies
 110                 // or build scripts, we only care about target dependencies that
 111                 // are in `deps`.
 112                 if let Some(maybe_target) = val.1
 113                     .parent()                   // chop off file name
 114                     .and_then(|p| p.parent())   // chop off `deps`
 115                     .and_then(|p| p.parent())   // chop off `release`
 116                     .and_then(|p| p.file_name())
 117                     .and_then(|p| p.to_str())
 118                 {
 119                     if maybe_target != &*target {
 120                         continue
 121                     }
 122                 }
 123
 124                 let mut artifacts = builder.tool_artifacts.borrow_mut();
 125                 let prev_artifacts = artifacts
 126                     .entry(target)
 127                     .or_default();
 128                 if let Some(prev) = prev_artifacts.get(&*id) {
 129                     if prev.1 != val.1 {
 130                         duplicates.push((
 131                             id.to_string(),
 132                             val,
 133                             prev.clone(),
 134                         ));
 135                     }
 136                     return
 137                 }
 138                 prev_artifacts.insert(id.to_string(), val);
 139             }
 140         });
 141
 142         if is_expected && !duplicates.is_empty() {
 143             println!("duplicate artifacts found when compiling a tool, this \
 144                       typically means that something was recompiled because \
 145                       a transitive dependency has different features activated \
 146                       than in a previous build:\n");
 147             println!("the following dependencies are duplicated although they \
 148                       have the same features enabled:");
 149             for (id, cur, prev) in duplicates.drain_filter(|(_, cur, prev)| cur.2 == prev.2) {
 150                 println!("  {}", id);
 151                 // same features
 152                 println!("    `{}` ({:?})\n    `{}` ({:?})", cur.0, cur.1, prev.0, prev.1);
 153             }
 154             println!("the following dependencies have different features:");
 155             for (id, cur, prev) in duplicates {
 156                 println!("  {}", id);
 157                 let cur_features: HashSet<_> = cur.2.into_iter().collect();
 158                 let prev_features: HashSet<_> = prev.2.into_iter().collect();
 159                 println!("    `{}` additionally enabled features {:?} at {:?}",
 160                          cur.0, &cur_features - &prev_features, cur.1);
 161                 println!("    `{}` additionally enabled features {:?} at {:?}",
 162                          prev.0, &prev_features - &cur_features, prev.1);
 163             }
 164             println!();
 165             println!("to fix this you will probably want to edit the local \
 166                       src/tools/rustc-workspace-hack/Cargo.toml crate, as \
 167                       that will update the dependency graph to ensure that \
 168                       these crates all share the same feature set");
 169             panic!("tools should not compile multiple copies of the same crate");
 170         }
 171
 172         builder.save_toolstate(tool, if is_expected {
 173             ToolState::TestFail
 174         } else {
 175             ToolState::BuildFail
 176         });
 177
 178         if !is_expected {
 179             if !is_optional_tool {
 180                 exit(1);
 181             } else {
 182                 None
 183             }
 184         } else {
 185             let cargo_out = builder.cargo_out(compiler, self.mode, target)
 186                 .join(exe(tool, &compiler.host));
 187             let bin = builder.tools_dir(compiler).join(exe(tool, &compiler.host));
 188             builder.copy(&cargo_out, &bin);
 189             Some(bin)
 190         }
 191     }
 192 }
 193
 194 pub fn prepare_tool_cargo(
 195     builder: &Builder,
 196     compiler: Compiler,
 197     mode: Mode,
 198     target: Interned<String>,
 199     command: &'static str,
 200     path: &'static str,
 201     source_type: SourceType,
 202     extra_features: &[String],
 203 ) -> Command {
 204     let mut cargo = builder.cargo(compiler, mode, target, command);
 205     let dir = builder.src.join(path);
 206     cargo.arg("--manifest-path").arg(dir.join("Cargo.toml"));
 207
 208     // We don't want to build tools dynamically as they'll be running across
 209     // stages and such and it's just easier if they're not dynamically linked.
 210     cargo.env("RUSTC_NO_PREFER_DYNAMIC", "1");
 211
 212     if source_type == SourceType::Submodule {
 213         cargo.env("RUSTC_EXTERNAL_TOOL", "1");
 214     }
 215
 216     let mut features = extra_features.iter().cloned().collect::<Vec<_>>();
 217     if builder.build.config.cargo_native_static {
 218         if path.ends_with("cargo") ||
 219             path.ends_with("rls") ||
 220             path.ends_with("clippy") ||
 221             path.ends_with("miri") ||
 222             path.ends_with("rustfmt")
 223         {
 224             cargo.env("LIBZ_SYS_STATIC", "1");
 225             features.push("rustc-workspace-hack/all-static".to_string());
 226         }
 227     }
 228
 229     // if tools are using lzma we want to force the build script to build its
 230     // own copy
 231     cargo.env("LZMA_API_STATIC", "1");
 232
 233     cargo.env("CFG_RELEASE_CHANNEL", &builder.config.channel);
 234     cargo.env("CFG_VERSION", builder.rust_version());
 235     cargo.env("CFG_RELEASE_NUM", channel::CFG_RELEASE_NUM);
 236
 237     let info = GitInfo::new(&builder.config, &dir);
 238     if let Some(sha) = info.sha() {
 239         cargo.env("CFG_COMMIT_HASH", sha);
 240     }
 241     if let Some(sha_short) = info.sha_short() {
 242         cargo.env("CFG_SHORT_COMMIT_HASH", sha_short);
 243     }
 244     if let Some(date) = info.commit_date() {
 245         cargo.env("CFG_COMMIT_DATE", date);
 246     }
 247     if !features.is_empty() {
 248         cargo.arg("--features").arg(&features.join(", "));
 249     }
 250     cargo
 251 }
 252
 253 macro_rules! tool {
 254     ($(
 255         $name:ident, $path:expr, $tool_name:expr, $mode:expr
 256         $(,llvm_tools = $llvm:expr)*
 257         $(,is_external_tool = $external:expr)*
 258         ;
 259     )+) => {
 260         #[derive(Copy, PartialEq, Eq, Clone)]
 261         pub enum Tool {
 262             $(
 263                 $name,
 264             )+
 265         }
 266
 267         impl Tool {
 268             pub fn get_mode(&self) -> Mode {
 269                 let mode = match self {
 270                     $(Tool::$name => $mode,)+
 271                 };
 272                 mode
 273             }
 274
 275             /// Whether this tool requires LLVM to run
 276             pub fn uses_llvm_tools(&self) -> bool {
 277                 match self {
 278                     $(Tool::$name => false $(|| $llvm)*,)+
 279                 }
 280             }
 281         }
 282
 283         impl<'a> Builder<'a> {
 284             pub fn tool_exe(&self, tool: Tool) -> PathBuf {
 285                 let stage = self.tool_default_stage(tool);
 286                 match tool {
 287                     $(Tool::$name =>
 288                         self.ensure($name {
 289                             compiler: self.compiler(stage, self.config.build),
 290                             target: self.config.build,
 291                         }),
 292                     )+
 293                 }
 294             }
 295
 296             pub fn tool_default_stage(&self, tool: Tool) -> u32 {
 297                 // Compile the error-index in the same stage as rustdoc to avoid
 298                 // recompiling rustdoc twice if we can. Otherwise compile
 299                 // everything else in stage0 as there's no need to rebootstrap
 300                 // everything.
 301                 match tool {
 302                     Tool::ErrorIndex if self.top_stage >= 2 => self.top_stage,
 303                     _ => 0,
 304                 }
 305             }
 306         }
 307
 308         $(
 309             #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 310         pub struct $name {
 311             pub compiler: Compiler,
 312             pub target: Interned<String>,
 313         }
 314
 315         impl Step for $name {
 316             type Output = PathBuf;
 317
 318             fn should_run(run: ShouldRun) -> ShouldRun {
 319                 run.path($path)
 320             }
 321
 322             fn make_run(run: RunConfig) {
 323                 run.builder.ensure($name {
 324                     compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 325                     target: run.target,
 326                 });
 327             }
 328
 329             fn run(self, builder: &Builder) -> PathBuf {
 330                 builder.ensure(ToolBuild {
 331                     compiler: self.compiler,
 332                     target: self.target,
 333                     tool: $tool_name,
 334                     mode: $mode,
 335                     path: $path,
 336                     is_optional_tool: false,
 337                     source_type: if false $(|| $external)* {
 338                         SourceType::Submodule
 339                     } else {
 340                         SourceType::InTree
 341                     },
 342                     extra_features: Vec::new(),
 343                 }).expect("expected to build -- essential tool")
 344             }
 345         }
 346         )+
 347     }
 348 }
 349
 350 tool!(
 351     Rustbook, "src/tools/rustbook", "rustbook", Mode::ToolBootstrap;
 352     ErrorIndex, "src/tools/error_index_generator", "error_index_generator", Mode::ToolRustc;
 353     UnstableBookGen, "src/tools/unstable-book-gen", "unstable-book-gen", Mode::ToolBootstrap;
 354     Tidy, "src/tools/tidy", "tidy", Mode::ToolBootstrap;
 355     Linkchecker, "src/tools/linkchecker", "linkchecker", Mode::ToolBootstrap;
 356     CargoTest, "src/tools/cargotest", "cargotest", Mode::ToolBootstrap;
 357     Compiletest, "src/tools/compiletest", "compiletest", Mode::ToolBootstrap, llvm_tools = true;
 358     BuildManifest, "src/tools/build-manifest", "build-manifest", Mode::ToolBootstrap;
 359     RemoteTestClient, "src/tools/remote-test-client", "remote-test-client", Mode::ToolBootstrap;
 360     RustInstaller, "src/tools/rust-installer", "fabricate", Mode::ToolBootstrap,
 361         is_external_tool = true;
 362     RustdocTheme, "src/tools/rustdoc-themes", "rustdoc-themes", Mode::ToolBootstrap;
 363 );
 364
 365 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 366 pub struct RemoteTestServer {
 367     pub compiler: Compiler,
 368     pub target: Interned<String>,
 369 }
 370
 371 impl Step for RemoteTestServer {
 372     type Output = PathBuf;
 373
 374     fn should_run(run: ShouldRun) -> ShouldRun {
 375         run.path("src/tools/remote-test-server")
 376     }
 377
 378     fn make_run(run: RunConfig) {
 379         run.builder.ensure(RemoteTestServer {
 380             compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 381             target: run.target,
 382         });
 383     }
 384
 385     fn run(self, builder: &Builder) -> PathBuf {
 386         builder.ensure(ToolBuild {
 387             compiler: self.compiler,
 388             target: self.target,
 389             tool: "remote-test-server",
 390             mode: Mode::ToolStd,
 391             path: "src/tools/remote-test-server",
 392             is_optional_tool: false,
 393             source_type: SourceType::InTree,
 394             extra_features: Vec::new(),
 395         }).expect("expected to build -- essential tool")
 396     }
 397 }
 398
 399 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 400 pub struct Rustdoc {
 401     pub host: Interned<String>,
 402 }
 403
 404 impl Step for Rustdoc {
 405     type Output = PathBuf;
 406     const DEFAULT: bool = true;
 407     const ONLY_HOSTS: bool = true;
 408
 409     fn should_run(run: ShouldRun) -> ShouldRun {
 410         run.path("src/tools/rustdoc")
 411     }
 412
 413     fn make_run(run: RunConfig) {
 414         run.builder.ensure(Rustdoc {
 415             host: run.host,
 416         });
 417     }
 418
 419     fn run(self, builder: &Builder) -> PathBuf {
 420         let target_compiler = builder.compiler(builder.top_stage, self.host);
 421         if target_compiler.stage == 0 {
 422             if !target_compiler.is_snapshot(builder) {
 423                 panic!("rustdoc in stage 0 must be snapshot rustdoc");
 424             }
 425             return builder.initial_rustc.with_file_name(exe("rustdoc", &target_compiler.host));
 426         }
 427         let target = target_compiler.host;
 428         // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
 429         // we'd have stageN/bin/rustc and stageN/bin/rustdoc be effectively different stage
 430         // compilers, which isn't what we want. Rustdoc should be linked in the same way as the
 431         // rustc compiler it's paired with, so it must be built with the previous stage compiler.
 432         let build_compiler = builder.compiler(target_compiler.stage - 1, builder.config.build);
 433
 434         // The presence of `target_compiler` ensures that the necessary libraries (codegen backends,
 435         // compiler libraries, ...) are built. Rustdoc does not require the presence of any
 436         // libraries within sysroot_libdir (i.e., rustlib), though doctests may want it (since
 437         // they'll be linked to those libraries). As such, don't explicitly `ensure` any additional
 438         // libraries here. The intuition here is that If we've built a compiler, we should be able
 439         // to build rustdoc.
 440
 441         let mut cargo = prepare_tool_cargo(
 442             builder,
 443             build_compiler,
 444             Mode::ToolRustc,
 445             target,
 446             "build",
 447             "src/tools/rustdoc",
 448             SourceType::InTree,
 449             &[],
 450         );
 451
 452         // Most tools don't get debuginfo, but rustdoc should.
 453         cargo.env("RUSTC_DEBUGINFO", builder.config.rust_debuginfo.to_string())
 454              .env("RUSTC_DEBUGINFO_LINES", builder.config.rust_debuginfo_lines.to_string());
 455
 456         let _folder = builder.fold_output(|| format!("stage{}-rustdoc", target_compiler.stage));
 457         builder.info(&format!("Building rustdoc for stage{} ({})",
 458             target_compiler.stage, target_compiler.host));
 459         builder.run(&mut cargo);
 460
 461         // Cargo adds a number of paths to the dylib search path on windows, which results in
 462         // the wrong rustdoc being executed. To avoid the conflicting rustdocs, we name the "tool"
 463         // rustdoc a different name.
 464         let tool_rustdoc = builder.cargo_out(build_compiler, Mode::ToolRustc, target)
 465             .join(exe("rustdoc_tool_binary", &target_compiler.host));
 466
 467         // don't create a stage0-sysroot/bin directory.
 468         if target_compiler.stage > 0 {
 469             let sysroot = builder.sysroot(target_compiler);
 470             let bindir = sysroot.join("bin");
 471             t!(fs::create_dir_all(&bindir));
 472             let bin_rustdoc = bindir.join(exe("rustdoc", &*target_compiler.host));
 473             let _ = fs::remove_file(&bin_rustdoc);
 474             builder.copy(&tool_rustdoc, &bin_rustdoc);
 475             bin_rustdoc
 476         } else {
 477             tool_rustdoc
 478         }
 479     }
 480 }
 481
 482 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 483 pub struct Cargo {
 484     pub compiler: Compiler,
 485     pub target: Interned<String>,
 486 }
 487
 488 impl Step for Cargo {
 489     type Output = PathBuf;
 490     const DEFAULT: bool = true;
 491     const ONLY_HOSTS: bool = true;
 492
 493     fn should_run(run: ShouldRun) -> ShouldRun {
 494         let builder = run.builder;
 495         run.path("src/tools/cargo").default_condition(builder.config.extended)
 496     }
 497
 498     fn make_run(run: RunConfig) {
 499         run.builder.ensure(Cargo {
 500             compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 501             target: run.target,
 502         });
 503     }
 504
 505     fn run(self, builder: &Builder) -> PathBuf {
 506         // Cargo depends on procedural macros, which requires a full host
 507         // compiler to be available, so we need to depend on that.
 508         builder.ensure(compile::Rustc {
 509             compiler: self.compiler,
 510             target: builder.config.build,
 511         });
 512         builder.ensure(ToolBuild {
 513             compiler: self.compiler,
 514             target: self.target,
 515             tool: "cargo",
 516             mode: Mode::ToolRustc,
 517             path: "src/tools/cargo",
 518             is_optional_tool: false,
 519             source_type: SourceType::Submodule,
 520             extra_features: Vec::new(),
 521         }).expect("expected to build -- essential tool")
 522     }
 523 }
 524
 525 macro_rules! tool_extended {
 526     (($sel:ident, $builder:ident),
 527        $($name:ident,
 528        $toolstate:ident,
 529        $path:expr,
 530        $tool_name:expr,
 531        $extra_deps:block;)+) => {
 532         $(
 533             #[derive(Debug, Clone, Hash, PartialEq, Eq)]
 534         pub struct $name {
 535             pub compiler: Compiler,
 536             pub target: Interned<String>,
 537             pub extra_features: Vec<String>,
 538         }
 539
 540         impl Step for $name {
 541             type Output = Option<PathBuf>;
 542             const DEFAULT: bool = true;
 543             const ONLY_HOSTS: bool = true;
 544
 545             fn should_run(run: ShouldRun) -> ShouldRun {
 546                 let builder = run.builder;
 547                 run.path($path).default_condition(builder.config.extended)
 548             }
 549
 550             fn make_run(run: RunConfig) {
 551                 run.builder.ensure($name {
 552                     compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 553                     target: run.target,
 554                     extra_features: Vec::new(),
 555                 });
 556             }
 557
 558             #[allow(unused_mut)]
 559             fn run(mut $sel, $builder: &Builder) -> Option<PathBuf> {
 560                 $extra_deps
 561                 $builder.ensure(ToolBuild {
 562                     compiler: $sel.compiler,
 563                     target: $sel.target,
 564                     tool: $tool_name,
 565                     mode: Mode::ToolRustc,
 566                     path: $path,
 567                     extra_features: $sel.extra_features,
 568                     is_optional_tool: true,
 569                     source_type: SourceType::Submodule,
 570                 })
 571             }
 572         }
 573         )+
 574     }
 575 }
 576
 577 tool_extended!((self, builder),
 578     Cargofmt, rustfmt, "src/tools/rustfmt", "cargo-fmt", {};
 579     CargoClippy, clippy, "src/tools/clippy", "cargo-clippy", {
 580         // Clippy depends on procedural macros (serde), which requires a full host
 581         // compiler to be available, so we need to depend on that.
 582         builder.ensure(compile::Rustc {
 583             compiler: self.compiler,
 584             target: builder.config.build,
 585         });
 586     };
 587     Clippy, clippy, "src/tools/clippy", "clippy-driver", {
 588         // Clippy depends on procedural macros (serde), which requires a full host
 589         // compiler to be available, so we need to depend on that.
 590         builder.ensure(compile::Rustc {
 591             compiler: self.compiler,
 592             target: builder.config.build,
 593         });
 594     };
 595     Miri, miri, "src/tools/miri", "miri", {};
 596     CargoMiri, miri, "src/tools/miri", "cargo-miri", {
 597         // Miri depends on procedural macros (serde), which requires a full host
 598         // compiler to be available, so we need to depend on that.
 599         builder.ensure(compile::Rustc {
 600             compiler: self.compiler,
 601             target: builder.config.build,
 602         });
 603     };
 604     Rls, rls, "src/tools/rls", "rls", {
 605         let clippy = builder.ensure(Clippy {
 606             compiler: self.compiler,
 607             target: self.target,
 608             extra_features: Vec::new(),
 609         });
 610         if clippy.is_some() {
 611             self.extra_features.push("clippy".to_owned());
 612         }
 613         // RLS depends on procedural macros, which requires a full host
 614         // compiler to be available, so we need to depend on that.
 615         builder.ensure(compile::Rustc {
 616             compiler: self.compiler,
 617             target: builder.config.build,
 618         });
 619     };
 620     Rustfmt, rustfmt, "src/tools/rustfmt", "rustfmt", {};
 621 );
 622
 623 impl<'a> Builder<'a> {
 624     /// Gets a `Command` which is ready to run `tool` in `stage` built for
 625     /// `host`.
 626     pub fn tool_cmd(&self, tool: Tool) -> Command {
 627         let mut cmd = Command::new(self.tool_exe(tool));
 628         let compiler = self.compiler(self.tool_default_stage(tool), self.config.build);
 629         self.prepare_tool_cmd(compiler, tool, &mut cmd);
 630         cmd
 631     }
 632
 633     /// Prepares the `cmd` provided to be able to run the `compiler` provided.
 634     ///
 635     /// Notably this munges the dynamic library lookup path to point to the
 636     /// right location to run `compiler`.
 637     fn prepare_tool_cmd(&self, compiler: Compiler, tool: Tool, cmd: &mut Command) {
 638         let host = &compiler.host;
 639         let mut lib_paths: Vec<PathBuf> = vec![
 640             if compiler.stage == 0 && tool != Tool::ErrorIndex {
 641                 self.build.rustc_snapshot_libdir()
 642             } else {
 643                 PathBuf::from(&self.sysroot_libdir(compiler, compiler.host))
 644             },
 645             self.cargo_out(compiler, tool.get_mode(), *host).join("deps"),
 646         ];
 647
 648         // On MSVC a tool may invoke a C compiler (e.g., compiletest in run-make
 649         // mode) and that C compiler may need some extra PATH modification. Do
 650         // so here.
 651         if compiler.host.contains("msvc") {
 652             let curpaths = env::var_os("PATH").unwrap_or_default();
 653             let curpaths = env::split_paths(&curpaths).collect::<Vec<_>>();
 654             for &(ref k, ref v) in self.cc[&compiler.host].env() {
 655                 if k != "PATH" {
 656                     continue
 657                 }
 658                 for path in env::split_paths(v) {
 659                     if !curpaths.contains(&path) {
 660                         lib_paths.push(path);
 661                     }
 662                 }
 663             }
 664         }
 665
 666         // Add the llvm/bin directory to PATH since it contains lots of
 667         // useful, platform-independent tools
 668         if tool.uses_llvm_tools() && !self.config.dry_run {
 669             let mut additional_paths = vec![];
 670
 671             if let Some(llvm_bin_path) = self.llvm_bin_path() {
 672                 additional_paths.push(llvm_bin_path);
 673             }
 674
 675             // If LLD is available, add that too.
 676             if self.config.lld_enabled {
 677                 let lld_install_root = self.ensure(native::Lld {
 678                     target: self.config.build,
 679                 });
 680
 681                 let lld_bin_path = lld_install_root.join("bin");
 682                 additional_paths.push(lld_bin_path);
 683             }
 684
 685             if host.contains("windows") {
 686                 // On Windows, PATH and the dynamic library path are the same,
 687                 // so we just add the LLVM bin path to lib_path
 688                 lib_paths.extend(additional_paths);
 689             } else {
 690                 let old_path = env::var_os("PATH").unwrap_or_default();
 691                 let new_path = env::join_paths(additional_paths.into_iter()
 692                         .chain(env::split_paths(&old_path)))
 693                     .expect("Could not add LLVM bin path to PATH");
 694                 cmd.env("PATH", new_path);
 695             }
 696         }
 697
 698         add_lib_path(lib_paths, cmd);
 699     }
 700
 701     fn llvm_bin_path(&self) -> Option<PathBuf> {
 702         if self.config.llvm_enabled {
 703             let llvm_config = self.ensure(native::Llvm {
 704                 target: self.config.build,
 705                 emscripten: false,
 706             });
 707
 708             // Add the llvm/bin directory to PATH since it contains lots of
 709             // useful, platform-independent tools
 710             let llvm_bin_path = llvm_config.parent()
 711                 .expect("Expected llvm-config to be contained in directory");
 712             assert!(llvm_bin_path.is_dir());
 713             Some(llvm_bin_path.to_path_buf())
 714         } else {
 715             None
 716         }
 717     }
 718 }