src/bootstrap/tool.rs

   1 // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use std::fs;
  12 use std::env;
  13 use std::iter;
  14 use std::path::PathBuf;
  15 use std::process::{Command, exit};
  16
  17 use Mode;
  18 use Compiler;
  19 use builder::{Step, RunConfig, ShouldRun, Builder};
  20 use util::{exe, add_lib_path};
  21 use compile::{self, libtest_stamp, libstd_stamp, librustc_stamp};
  22 use native;
  23 use channel::GitInfo;
  24 use cache::Interned;
  25 use toolstate::ToolState;
  26
  27 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
  28 pub struct CleanTools {
  29     pub compiler: Compiler,
  30     pub target: Interned<String>,
  31     pub mode: Mode,
  32 }
  33
  34 impl Step for CleanTools {
  35     type Output = ();
  36
  37     fn should_run(run: ShouldRun) -> ShouldRun {
  38         run.never()
  39     }
  40
  41     fn run(self, builder: &Builder) {
  42         let compiler = self.compiler;
  43         let target = self.target;
  44         let mode = self.mode;
  45
  46         // This is for the original compiler, but if we're forced to use stage 1, then
  47         // std/test/rustc stamps won't exist in stage 2, so we need to get those from stage 1, since
  48         // we copy the libs forward.
  49         let tools_dir = builder.stage_out(compiler, Mode::Tool);
  50         let compiler = if builder.force_use_stage1(compiler, target) {
  51             builder.compiler(1, compiler.host)
  52         } else {
  53             compiler
  54         };
  55
  56         for &cur_mode in &[Mode::Libstd, Mode::Libtest, Mode::Librustc] {
  57             let stamp = match cur_mode {
  58                 Mode::Libstd => libstd_stamp(builder, compiler, target),
  59                 Mode::Libtest => libtest_stamp(builder, compiler, target),
  60                 Mode::Librustc => librustc_stamp(builder, compiler, target),
  61                 _ => panic!(),
  62             };
  63
  64             if builder.clear_if_dirty(&tools_dir, &stamp) {
  65                 break;
  66             }
  67
  68             // If we are a rustc tool, and std changed, we also need to clear ourselves out -- our
  69             // dependencies depend on std. Therefore, we iterate up until our own mode.
  70             if mode == cur_mode {
  71                 break;
  72             }
  73         }
  74     }
  75 }
  76
  77 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
  78 struct ToolBuild {
  79     compiler: Compiler,
  80     target: Interned<String>,
  81     tool: &'static str,
  82     path: &'static str,
  83     mode: Mode,
  84     is_ext_tool: bool,
  85     extra_features: Vec<String>,
  86 }
  87
  88 impl Step for ToolBuild {
  89     type Output = Option<PathBuf>;
  90
  91     fn should_run(run: ShouldRun) -> ShouldRun {
  92         run.never()
  93     }
  94
  95     /// Build a tool in `src/tools`
  96     ///
  97     /// This will build the specified tool with the specified `host` compiler in
  98     /// `stage` into the normal cargo output directory.
  99     fn run(self, builder: &Builder) -> Option<PathBuf> {
 100         let compiler = self.compiler;
 101         let target = self.target;
 102         let tool = self.tool;
 103         let path = self.path;
 104         let is_ext_tool = self.is_ext_tool;
 105
 106         match self.mode {
 107             Mode::Libstd => builder.ensure(compile::Std { compiler, target }),
 108             Mode::Libtest => builder.ensure(compile::Test { compiler, target }),
 109             Mode::Librustc => builder.ensure(compile::Rustc { compiler, target }),
 110             Mode::Tool => panic!("unexpected Mode::Tool for tool build")
 111         }
 112
 113         let mut cargo = prepare_tool_cargo(builder, compiler, target, "build", path);
 114         cargo.arg("--features").arg(self.extra_features.join(" "));
 115
 116         let _folder = builder.fold_output(|| format!("stage{}-{}", compiler.stage, tool));
 117         builder.info(&format!("Building stage{} tool {} ({})", compiler.stage, tool, target));
 118         let mut duplicates = Vec::new();
 119         let is_expected = compile::stream_cargo(builder, &mut cargo, &mut |msg| {
 120             // Only care about big things like the RLS/Cargo for now
 121             if tool != "rls" && tool != "cargo" {
 122                 return
 123             }
 124             let (id, features, filenames) = match msg {
 125                 compile::CargoMessage::CompilerArtifact {
 126                     package_id,
 127                     features,
 128                     filenames
 129                 } => {
 130                     (package_id, features, filenames)
 131                 }
 132                 _ => return,
 133             };
 134             let features = features.iter().map(|s| s.to_string()).collect::<Vec<_>>();
 135
 136             for path in filenames {
 137                 let val = (tool, PathBuf::from(&*path), features.clone());
 138                 // we're only interested in deduplicating rlibs for now
 139                 if val.1.extension().and_then(|s| s.to_str()) != Some("rlib") {
 140                     continue
 141                 }
 142
 143                 // Don't worry about libs that turn out to be host dependencies
 144                 // or build scripts, we only care about target dependencies that
 145                 // are in `deps`.
 146                 if let Some(maybe_target) = val.1
 147                     .parent()                   // chop off file name
 148                     .and_then(|p| p.parent())   // chop off `deps`
 149                     .and_then(|p| p.parent())   // chop off `release`
 150                     .and_then(|p| p.file_name())
 151                     .and_then(|p| p.to_str())
 152                 {
 153                     if maybe_target != &*target {
 154                         continue
 155                     }
 156                 }
 157
 158                 let mut artifacts = builder.tool_artifacts.borrow_mut();
 159                 let prev_artifacts = artifacts
 160                     .entry(target)
 161                     .or_insert_with(Default::default);
 162                 if let Some(prev) = prev_artifacts.get(&*id) {
 163                     if prev.1 != val.1 {
 164                         duplicates.push((
 165                             id.to_string(),
 166                             val,
 167                             prev.clone(),
 168                         ));
 169                     }
 170                     return
 171                 }
 172                 prev_artifacts.insert(id.to_string(), val);
 173             }
 174         });
 175
 176         if is_expected && duplicates.len() != 0 {
 177             println!("duplicate artfacts found when compiling a tool, this \
 178                       typically means that something was recompiled because \
 179                       a transitive dependency has different features activated \
 180                       than in a previous build:\n");
 181             for (id, cur, prev) in duplicates {
 182                 println!("  {}", id);
 183                 println!("    `{}` enabled features {:?} at {:?}",
 184                          cur.0, cur.2, cur.1);
 185                 println!("    `{}` enabled features {:?} at {:?}",
 186                          prev.0, prev.2, prev.1);
 187             }
 188             println!("");
 189             panic!("tools should not compile multiple copies of the same crate");
 190         }
 191
 192         builder.save_toolstate(tool, if is_expected {
 193             ToolState::TestFail
 194         } else {
 195             ToolState::BuildFail
 196         });
 197
 198         if !is_expected {
 199             if !is_ext_tool {
 200                 exit(1);
 201             } else {
 202                 return None;
 203             }
 204         } else {
 205             let cargo_out = builder.cargo_out(compiler, Mode::Tool, target)
 206                 .join(exe(tool, &compiler.host));
 207             let bin = builder.tools_dir(compiler).join(exe(tool, &compiler.host));
 208             builder.copy(&cargo_out, &bin);
 209             Some(bin)
 210         }
 211     }
 212 }
 213
 214 pub fn prepare_tool_cargo(
 215     builder: &Builder,
 216     compiler: Compiler,
 217     target: Interned<String>,
 218     command: &'static str,
 219     path: &'static str,
 220 ) -> Command {
 221     let mut cargo = builder.cargo(compiler, Mode::Tool, target, command);
 222     let dir = builder.src.join(path);
 223     cargo.arg("--manifest-path").arg(dir.join("Cargo.toml"));
 224
 225     // We don't want to build tools dynamically as they'll be running across
 226     // stages and such and it's just easier if they're not dynamically linked.
 227     cargo.env("RUSTC_NO_PREFER_DYNAMIC", "1");
 228
 229     if let Some(dir) = builder.openssl_install_dir(target) {
 230         cargo.env("OPENSSL_STATIC", "1");
 231         cargo.env("OPENSSL_DIR", dir);
 232         cargo.env("LIBZ_SYS_STATIC", "1");
 233     }
 234
 235     // if tools are using lzma we want to force the build script to build its
 236     // own copy
 237     cargo.env("LZMA_API_STATIC", "1");
 238
 239     cargo.env("CFG_RELEASE_CHANNEL", &builder.config.channel);
 240     cargo.env("CFG_VERSION", builder.rust_version());
 241
 242     let info = GitInfo::new(&builder.config, &dir);
 243     if let Some(sha) = info.sha() {
 244         cargo.env("CFG_COMMIT_HASH", sha);
 245     }
 246     if let Some(sha_short) = info.sha_short() {
 247         cargo.env("CFG_SHORT_COMMIT_HASH", sha_short);
 248     }
 249     if let Some(date) = info.commit_date() {
 250         cargo.env("CFG_COMMIT_DATE", date);
 251     }
 252     cargo
 253 }
 254
 255 macro_rules! tool {
 256     ($($name:ident, $path:expr, $tool_name:expr, $mode:expr;)+) => {
 257         #[derive(Copy, Clone)]
 258         pub enum Tool {
 259             $(
 260                 $name,
 261             )+
 262         }
 263
 264         impl<'a> Builder<'a> {
 265             pub fn tool_exe(&self, tool: Tool) -> PathBuf {
 266                 let stage = self.tool_default_stage(tool);
 267                 match tool {
 268                     $(Tool::$name =>
 269                         self.ensure($name {
 270                             compiler: self.compiler(stage, self.config.build),
 271                             target: self.config.build,
 272                         }),
 273                     )+
 274                 }
 275             }
 276
 277             pub fn tool_default_stage(&self, tool: Tool) -> u32 {
 278                 // Compile the error-index in the same stage as rustdoc to avoid
 279                 // recompiling rustdoc twice if we can. Otherwise compile
 280                 // everything else in stage0 as there's no need to rebootstrap
 281                 // everything.
 282                 match tool {
 283                     Tool::ErrorIndex if self.top_stage >= 2 => self.top_stage,
 284                     _ => 0,
 285                 }
 286             }
 287         }
 288
 289         $(
 290             #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 291         pub struct $name {
 292             pub compiler: Compiler,
 293             pub target: Interned<String>,
 294         }
 295
 296         impl Step for $name {
 297             type Output = PathBuf;
 298
 299             fn should_run(run: ShouldRun) -> ShouldRun {
 300                 run.path($path)
 301             }
 302
 303             fn make_run(run: RunConfig) {
 304                 run.builder.ensure($name {
 305                     compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 306                     target: run.target,
 307                 });
 308             }
 309
 310             fn run(self, builder: &Builder) -> PathBuf {
 311                 builder.ensure(ToolBuild {
 312                     compiler: self.compiler,
 313                     target: self.target,
 314                     tool: $tool_name,
 315                     mode: $mode,
 316                     path: $path,
 317                     is_ext_tool: false,
 318                     extra_features: Vec::new(),
 319                 }).expect("expected to build -- essential tool")
 320             }
 321         }
 322         )+
 323     }
 324 }
 325
 326 tool!(
 327     Rustbook, "src/tools/rustbook", "rustbook", Mode::Librustc;
 328     ErrorIndex, "src/tools/error_index_generator", "error_index_generator", Mode::Librustc;
 329     UnstableBookGen, "src/tools/unstable-book-gen", "unstable-book-gen", Mode::Libstd;
 330     Tidy, "src/tools/tidy", "tidy", Mode::Libstd;
 331     Linkchecker, "src/tools/linkchecker", "linkchecker", Mode::Libstd;
 332     CargoTest, "src/tools/cargotest", "cargotest", Mode::Libstd;
 333     Compiletest, "src/tools/compiletest", "compiletest", Mode::Libtest;
 334     BuildManifest, "src/tools/build-manifest", "build-manifest", Mode::Libstd;
 335     RemoteTestClient, "src/tools/remote-test-client", "remote-test-client", Mode::Libstd;
 336     RustInstaller, "src/tools/rust-installer", "fabricate", Mode::Libstd;
 337     RustdocTheme, "src/tools/rustdoc-themes", "rustdoc-themes", Mode::Libstd;
 338 );
 339
 340 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 341 pub struct RemoteTestServer {
 342     pub compiler: Compiler,
 343     pub target: Interned<String>,
 344 }
 345
 346 impl Step for RemoteTestServer {
 347     type Output = PathBuf;
 348
 349     fn should_run(run: ShouldRun) -> ShouldRun {
 350         run.path("src/tools/remote-test-server")
 351     }
 352
 353     fn make_run(run: RunConfig) {
 354         run.builder.ensure(RemoteTestServer {
 355             compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 356             target: run.target,
 357         });
 358     }
 359
 360     fn run(self, builder: &Builder) -> PathBuf {
 361         builder.ensure(ToolBuild {
 362             compiler: self.compiler,
 363             target: self.target,
 364             tool: "remote-test-server",
 365             mode: Mode::Libstd,
 366             path: "src/tools/remote-test-server",
 367             is_ext_tool: false,
 368             extra_features: Vec::new(),
 369         }).expect("expected to build -- essential tool")
 370     }
 371 }
 372
 373 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 374 pub struct Rustdoc {
 375     pub host: Interned<String>,
 376 }
 377
 378 impl Step for Rustdoc {
 379     type Output = PathBuf;
 380     const DEFAULT: bool = true;
 381     const ONLY_HOSTS: bool = true;
 382
 383     fn should_run(run: ShouldRun) -> ShouldRun {
 384         run.path("src/tools/rustdoc")
 385     }
 386
 387     fn make_run(run: RunConfig) {
 388         run.builder.ensure(Rustdoc {
 389             host: run.host,
 390         });
 391     }
 392
 393     fn run(self, builder: &Builder) -> PathBuf {
 394         let target_compiler = builder.compiler(builder.top_stage, self.host);
 395         let target = target_compiler.host;
 396         let build_compiler = if target_compiler.stage == 0 {
 397             builder.compiler(0, builder.config.build)
 398         } else if target_compiler.stage >= 2 {
 399             // Past stage 2, we consider the compiler to be ABI-compatible and hence capable of
 400             // building rustdoc itself.
 401             builder.compiler(target_compiler.stage, builder.config.build)
 402         } else {
 403             // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
 404             // we'd have stageN/bin/rustc and stageN/bin/rustdoc be effectively different stage
 405             // compilers, which isn't what we want.
 406             builder.compiler(target_compiler.stage - 1, builder.config.build)
 407         };
 408
 409         builder.ensure(compile::Rustc { compiler: build_compiler, target });
 410         builder.ensure(compile::Rustc {
 411             compiler: build_compiler,
 412             target: builder.config.build,
 413         });
 414
 415         let mut cargo = prepare_tool_cargo(builder,
 416                                            build_compiler,
 417                                            target,
 418                                            "build",
 419                                            "src/tools/rustdoc");
 420
 421         // Most tools don't get debuginfo, but rustdoc should.
 422         cargo.env("RUSTC_DEBUGINFO", builder.config.rust_debuginfo.to_string())
 423              .env("RUSTC_DEBUGINFO_LINES", builder.config.rust_debuginfo_lines.to_string());
 424
 425         let _folder = builder.fold_output(|| format!("stage{}-rustdoc", target_compiler.stage));
 426         builder.info(&format!("Building rustdoc for stage{} ({})",
 427             target_compiler.stage, target_compiler.host));
 428         builder.run(&mut cargo);
 429
 430         // Cargo adds a number of paths to the dylib search path on windows, which results in
 431         // the wrong rustdoc being executed. To avoid the conflicting rustdocs, we name the "tool"
 432         // rustdoc a different name.
 433         let tool_rustdoc = builder.cargo_out(build_compiler, Mode::Tool, target)
 434             .join(exe("rustdoc-tool-binary", &target_compiler.host));
 435
 436         // don't create a stage0-sysroot/bin directory.
 437         if target_compiler.stage > 0 {
 438             let sysroot = builder.sysroot(target_compiler);
 439             let bindir = sysroot.join("bin");
 440             t!(fs::create_dir_all(&bindir));
 441             let bin_rustdoc = bindir.join(exe("rustdoc", &*target_compiler.host));
 442             let _ = fs::remove_file(&bin_rustdoc);
 443             builder.copy(&tool_rustdoc, &bin_rustdoc);
 444             bin_rustdoc
 445         } else {
 446             tool_rustdoc
 447         }
 448     }
 449 }
 450
 451 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 452 pub struct Cargo {
 453     pub compiler: Compiler,
 454     pub target: Interned<String>,
 455 }
 456
 457 impl Step for Cargo {
 458     type Output = PathBuf;
 459     const DEFAULT: bool = true;
 460     const ONLY_HOSTS: bool = true;
 461
 462     fn should_run(run: ShouldRun) -> ShouldRun {
 463         let builder = run.builder;
 464         run.path("src/tools/cargo").default_condition(builder.config.extended)
 465     }
 466
 467     fn make_run(run: RunConfig) {
 468         run.builder.ensure(Cargo {
 469             compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 470             target: run.target,
 471         });
 472     }
 473
 474     fn run(self, builder: &Builder) -> PathBuf {
 475         builder.ensure(native::Openssl {
 476             target: self.target,
 477         });
 478         // Cargo depends on procedural macros, which requires a full host
 479         // compiler to be available, so we need to depend on that.
 480         builder.ensure(compile::Rustc {
 481             compiler: self.compiler,
 482             target: builder.config.build,
 483         });
 484         builder.ensure(ToolBuild {
 485             compiler: self.compiler,
 486             target: self.target,
 487             tool: "cargo",
 488             mode: Mode::Librustc,
 489             path: "src/tools/cargo",
 490             is_ext_tool: false,
 491             extra_features: Vec::new(),
 492         }).expect("expected to build -- essential tool")
 493     }
 494 }
 495
 496 macro_rules! tool_extended {
 497     (($sel:ident, $builder:ident),
 498        $($name:ident,
 499        $toolstate:ident,
 500        $path:expr,
 501        $tool_name:expr,
 502        $extra_deps:block;)+) => {
 503         $(
 504             #[derive(Debug, Clone, Hash, PartialEq, Eq)]
 505         pub struct $name {
 506             pub compiler: Compiler,
 507             pub target: Interned<String>,
 508             pub extra_features: Vec<String>,
 509         }
 510
 511         impl Step for $name {
 512             type Output = Option<PathBuf>;
 513             const DEFAULT: bool = true;
 514             const ONLY_HOSTS: bool = true;
 515
 516             fn should_run(run: ShouldRun) -> ShouldRun {
 517                 let builder = run.builder;
 518                 run.path($path).default_condition(builder.config.extended)
 519             }
 520
 521             fn make_run(run: RunConfig) {
 522                 run.builder.ensure($name {
 523                     compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
 524                     target: run.target,
 525                     extra_features: Vec::new(),
 526                 });
 527             }
 528
 529             #[allow(unused_mut)]
 530             fn run(mut $sel, $builder: &Builder) -> Option<PathBuf> {
 531                 $extra_deps
 532                 $builder.ensure(ToolBuild {
 533                     compiler: $sel.compiler,
 534                     target: $sel.target,
 535                     tool: $tool_name,
 536                     mode: Mode::Librustc,
 537                     path: $path,
 538                     extra_features: $sel.extra_features,
 539                     is_ext_tool: true,
 540                 })
 541             }
 542         }
 543         )+
 544     }
 545 }
 546
 547 tool_extended!((self, builder),
 548     Cargofmt, rustfmt, "src/tools/rustfmt", "cargo-fmt", {};
 549     Clippy, clippy, "src/tools/clippy", "clippy-driver", {
 550         // Clippy depends on procedural macros (serde), which requires a full host
 551         // compiler to be available, so we need to depend on that.
 552         builder.ensure(compile::Rustc {
 553             compiler: self.compiler,
 554             target: builder.config.build,
 555         });
 556     };
 557     Miri, miri, "src/tools/miri", "miri", {};
 558     Rls, rls, "src/tools/rls", "rls", {
 559         builder.ensure(native::Openssl {
 560             target: self.target,
 561         });
 562         // RLS depends on procedural macros, which requires a full host
 563         // compiler to be available, so we need to depend on that.
 564         builder.ensure(compile::Rustc {
 565             compiler: self.compiler,
 566             target: builder.config.build,
 567         });
 568     };
 569     Rustfmt, rustfmt, "src/tools/rustfmt", "rustfmt", {};
 570 );
 571
 572 impl<'a> Builder<'a> {
 573     /// Get a `Command` which is ready to run `tool` in `stage` built for
 574     /// `host`.
 575     pub fn tool_cmd(&self, tool: Tool) -> Command {
 576         let mut cmd = Command::new(self.tool_exe(tool));
 577         let compiler = self.compiler(self.tool_default_stage(tool), self.config.build);
 578         self.prepare_tool_cmd(compiler, &mut cmd);
 579         cmd
 580     }
 581
 582     /// Prepares the `cmd` provided to be able to run the `compiler` provided.
 583     ///
 584     /// Notably this munges the dynamic library lookup path to point to the
 585     /// right location to run `compiler`.
 586     fn prepare_tool_cmd(&self, compiler: Compiler, cmd: &mut Command) {
 587         let host = &compiler.host;
 588         let mut lib_paths: Vec<PathBuf> = vec![
 589             PathBuf::from(&self.sysroot_libdir(compiler, compiler.host)),
 590             self.cargo_out(compiler, Mode::Tool, *host).join("deps"),
 591         ];
 592
 593         // On MSVC a tool may invoke a C compiler (e.g. compiletest in run-make
 594         // mode) and that C compiler may need some extra PATH modification. Do
 595         // so here.
 596         if compiler.host.contains("msvc") {
 597             let curpaths = env::var_os("PATH").unwrap_or_default();
 598             let curpaths = env::split_paths(&curpaths).collect::<Vec<_>>();
 599             for &(ref k, ref v) in self.cc[&compiler.host].env() {
 600                 if k != "PATH" {
 601                     continue
 602                 }
 603                 for path in env::split_paths(v) {
 604                     if !curpaths.contains(&path) {
 605                         lib_paths.push(path);
 606                     }
 607                 }
 608             }
 609         }
 610
 611         // Add the llvm/bin directory to PATH since it contains lots of
 612         // useful, platform-independent tools
 613         if let Some(llvm_bin_path) = self.llvm_bin_path() {
 614             if host.contains("windows") {
 615                 // On Windows, PATH and the dynamic library path are the same,
 616                 // so we just add the LLVM bin path to lib_path
 617                 lib_paths.push(llvm_bin_path);
 618             } else {
 619                 let old_path = env::var_os("PATH").unwrap_or_default();
 620                 let new_path = env::join_paths(iter::once(llvm_bin_path)
 621                         .chain(env::split_paths(&old_path)))
 622                     .expect("Could not add LLVM bin path to PATH");
 623                 cmd.env("PATH", new_path);
 624             }
 625         }
 626
 627         add_lib_path(lib_paths, cmd);
 628     }
 629
 630     fn llvm_bin_path(&self) -> Option<PathBuf> {
 631         if self.config.llvm_enabled && !self.config.dry_run {
 632             let llvm_config = self.ensure(native::Llvm {
 633                 target: self.config.build,
 634                 emscripten: false,
 635             });
 636
 637             // Add the llvm/bin directory to PATH since it contains lots of
 638             // useful, platform-independent tools
 639             let llvm_bin_path = llvm_config.parent()
 640                 .expect("Expected llvm-config to be contained in directory");
 641             assert!(llvm_bin_path.is_dir());
 642             Some(llvm_bin_path.to_path_buf())
 643         } else {
 644             None
 645         }
 646     }
 647 }