src/bootstrap/builder.rs

   1 use std::any::Any;
   2 use std::cell::{Cell, RefCell};
   3 use std::collections::BTreeSet;
   4 use std::collections::HashMap;
   5 use std::env;
   6 use std::ffi::OsStr;
   7 use std::fmt::Debug;
   8 use std::fs;
   9 use std::hash::Hash;
  10 use std::ops::Deref;
  11 use std::path::{Path, PathBuf};
  12 use std::process::Command;
  13 use std::time::{Duration, Instant};
  14
  15 use build_helper::t;
  16
  17 use crate::cache::{Cache, Interned, INTERNER};
  18 use crate::check;
  19 use crate::compile;
  20 use crate::dist;
  21 use crate::doc;
  22 use crate::flags::Subcommand;
  23 use crate::install;
  24 use crate::native;
  25 use crate::test;
  26 use crate::tool;
  27 use crate::util::{self, add_lib_path, exe, libdir};
  28 use crate::{Build, DocTests, Mode, GitRepo};
  29
  30 pub use crate::Compiler;
  31
  32 use petgraph::graph::NodeIndex;
  33 use petgraph::Graph;
  34
  35 pub struct Builder<'a> {
  36     pub build: &'a Build,
  37     pub top_stage: u32,
  38     pub kind: Kind,
  39     cache: Cache,
  40     stack: RefCell<Vec<Box<dyn Any>>>,
  41     time_spent_on_dependencies: Cell<Duration>,
  42     pub paths: Vec<PathBuf>,
  43     graph_nodes: RefCell<HashMap<String, NodeIndex>>,
  44     graph: RefCell<Graph<String, bool>>,
  45     parent: Cell<Option<NodeIndex>>,
  46 }
  47
  48 impl<'a> Deref for Builder<'a> {
  49     type Target = Build;
  50
  51     fn deref(&self) -> &Self::Target {
  52         self.build
  53     }
  54 }
  55
  56 pub trait Step: 'static + Clone + Debug + PartialEq + Eq + Hash {
  57     /// `PathBuf` when directories are created or to return a `Compiler` once
  58     /// it's been assembled.
  59     type Output: Clone;
  60
  61     const DEFAULT: bool = false;
  62
  63     /// If true, then this rule should be skipped if --target was specified, but --host was not
  64     const ONLY_HOSTS: bool = false;
  65
  66     /// Primary function to execute this rule. Can call `builder.ensure()`
  67     /// with other steps to run those.
  68     fn run(self, builder: &Builder<'_>) -> Self::Output;
  69
  70     /// When bootstrap is passed a set of paths, this controls whether this rule
  71     /// will execute. However, it does not get called in a "default" context
  72     /// when we are not passed any paths; in that case, `make_run` is called
  73     /// directly.
  74     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_>;
  75
  76     /// Builds up a "root" rule, either as a default rule or from a path passed
  77     /// to us.
  78     ///
  79     /// When path is `None`, we are executing in a context where no paths were
  80     /// passed. When `./x.py build` is run, for example, this rule could get
  81     /// called if it is in the correct list below with a path of `None`.
  82     fn make_run(_run: RunConfig<'_>) {
  83         // It is reasonable to not have an implementation of make_run for rules
  84         // who do not want to get called from the root context. This means that
  85         // they are likely dependencies (e.g., sysroot creation) or similar, and
  86         // as such calling them from ./x.py isn't logical.
  87         unimplemented!()
  88     }
  89 }
  90
  91 pub struct RunConfig<'a> {
  92     pub builder: &'a Builder<'a>,
  93     pub host: Interned<String>,
  94     pub target: Interned<String>,
  95     pub path: PathBuf,
  96 }
  97
  98 struct StepDescription {
  99     default: bool,
 100     only_hosts: bool,
 101     should_run: fn(ShouldRun<'_>) -> ShouldRun<'_>,
 102     make_run: fn(RunConfig<'_>),
 103     name: &'static str,
 104 }
 105
 106 #[derive(Debug, Clone, PartialOrd, Ord, PartialEq, Eq)]
 107 pub enum PathSet {
 108     Set(BTreeSet<PathBuf>),
 109     Suite(PathBuf),
 110 }
 111
 112 impl PathSet {
 113     fn empty() -> PathSet {
 114         PathSet::Set(BTreeSet::new())
 115     }
 116
 117     fn one<P: Into<PathBuf>>(path: P) -> PathSet {
 118         let mut set = BTreeSet::new();
 119         set.insert(path.into());
 120         PathSet::Set(set)
 121     }
 122
 123     fn has(&self, needle: &Path) -> bool {
 124         match self {
 125             PathSet::Set(set) => set.iter().any(|p| p.ends_with(needle)),
 126             PathSet::Suite(suite) => suite.ends_with(needle),
 127         }
 128     }
 129
 130     fn path(&self, builder: &Builder<'_>) -> PathBuf {
 131         match self {
 132             PathSet::Set(set) => set
 133                 .iter()
 134                 .next()
 135                 .unwrap_or(&builder.build.src)
 136                 .to_path_buf(),
 137             PathSet::Suite(path) => PathBuf::from(path),
 138         }
 139     }
 140 }
 141
 142 impl StepDescription {
 143     fn from<S: Step>() -> StepDescription {
 144         StepDescription {
 145             default: S::DEFAULT,
 146             only_hosts: S::ONLY_HOSTS,
 147             should_run: S::should_run,
 148             make_run: S::make_run,
 149             name: std::any::type_name::<S>(),
 150         }
 151     }
 152
 153     fn maybe_run(&self, builder: &Builder<'_>, pathset: &PathSet) {
 154         if builder.config.exclude.iter().any(|e| pathset.has(e)) {
 155             eprintln!("Skipping {:?} because it is excluded", pathset);
 156             return;
 157         } else if !builder.config.exclude.is_empty() {
 158             eprintln!(
 159                 "{:?} not skipped for {:?} -- not in {:?}",
 160                 pathset, self.name, builder.config.exclude
 161             );
 162         }
 163         let hosts = &builder.hosts;
 164
 165         // Determine the targets participating in this rule.
 166         let targets = if self.only_hosts {
 167             if builder.config.skip_only_host_steps {
 168                 return; // don't run anything
 169             } else {
 170                 &builder.hosts
 171             }
 172         } else {
 173             &builder.targets
 174         };
 175
 176         for host in hosts {
 177             for target in targets {
 178                 let run = RunConfig {
 179                     builder,
 180                     path: pathset.path(builder),
 181                     host: *host,
 182                     target: *target,
 183                 };
 184                 (self.make_run)(run);
 185             }
 186         }
 187     }
 188
 189     fn run(v: &[StepDescription], builder: &Builder<'_>, paths: &[PathBuf]) {
 190         let should_runs = v
 191             .iter()
 192             .map(|desc| (desc.should_run)(ShouldRun::new(builder)))
 193             .collect::<Vec<_>>();
 194
 195         // sanity checks on rules
 196         for (desc, should_run) in v.iter().zip(&should_runs) {
 197             assert!(
 198                 !should_run.paths.is_empty(),
 199                 "{:?} should have at least one pathset",
 200                 desc.name
 201             );
 202         }
 203
 204         if paths.is_empty() {
 205             for (desc, should_run) in v.iter().zip(should_runs) {
 206                 if desc.default && should_run.is_really_default {
 207                     for pathset in &should_run.paths {
 208                         desc.maybe_run(builder, pathset);
 209                     }
 210                 }
 211             }
 212         } else {
 213             for path in paths {
 214                 // strip CurDir prefix if present
 215                 let path = match path.strip_prefix(".") {
 216                     Ok(p) => p,
 217                     Err(_) => path,
 218                 };
 219
 220                 let mut attempted_run = false;
 221                 for (desc, should_run) in v.iter().zip(&should_runs) {
 222                     if let Some(suite) = should_run.is_suite_path(path) {
 223                         attempted_run = true;
 224                         desc.maybe_run(builder, suite);
 225                     } else if let Some(pathset) = should_run.pathset_for_path(path) {
 226                         attempted_run = true;
 227                         desc.maybe_run(builder, pathset);
 228                     }
 229                 }
 230
 231                 if !attempted_run {
 232                     panic!("Error: no rules matched {}.", path.display());
 233                 }
 234             }
 235         }
 236     }
 237 }
 238
 239 #[derive(Clone)]
 240 pub struct ShouldRun<'a> {
 241     pub builder: &'a Builder<'a>,
 242     // use a BTreeSet to maintain sort order
 243     paths: BTreeSet<PathSet>,
 244
 245     // If this is a default rule, this is an additional constraint placed on
 246     // its run. Generally something like compiler docs being enabled.
 247     is_really_default: bool,
 248 }
 249
 250 impl<'a> ShouldRun<'a> {
 251     fn new(builder: &'a Builder<'_>) -> ShouldRun<'a> {
 252         ShouldRun {
 253             builder,
 254             paths: BTreeSet::new(),
 255             is_really_default: true, // by default no additional conditions
 256         }
 257     }
 258
 259     pub fn default_condition(mut self, cond: bool) -> Self {
 260         self.is_really_default = cond;
 261         self
 262     }
 263
 264     // Unlike `krate` this will create just one pathset. As such, it probably shouldn't actually
 265     // ever be used, but as we transition to having all rules properly handle passing krate(...) by
 266     // actually doing something different for every crate passed.
 267     pub fn all_krates(mut self, name: &str) -> Self {
 268         let mut set = BTreeSet::new();
 269         for krate in self.builder.in_tree_crates(name) {
 270             set.insert(PathBuf::from(&krate.path));
 271         }
 272         self.paths.insert(PathSet::Set(set));
 273         self
 274     }
 275
 276     pub fn krate(mut self, name: &str) -> Self {
 277         for krate in self.builder.in_tree_crates(name) {
 278             self.paths.insert(PathSet::one(&krate.path));
 279         }
 280         self
 281     }
 282
 283     // single, non-aliased path
 284     pub fn path(self, path: &str) -> Self {
 285         self.paths(&[path])
 286     }
 287
 288     // multiple aliases for the same job
 289     pub fn paths(mut self, paths: &[&str]) -> Self {
 290         self.paths
 291             .insert(PathSet::Set(paths.iter().map(PathBuf::from).collect()));
 292         self
 293     }
 294
 295     pub fn is_suite_path(&self, path: &Path) -> Option<&PathSet> {
 296         self.paths.iter().find(|pathset| match pathset {
 297             PathSet::Suite(p) => path.starts_with(p),
 298             PathSet::Set(_) => false,
 299         })
 300     }
 301
 302     pub fn suite_path(mut self, suite: &str) -> Self {
 303         self.paths.insert(PathSet::Suite(PathBuf::from(suite)));
 304         self
 305     }
 306
 307     // allows being more explicit about why should_run in Step returns the value passed to it
 308     pub fn never(mut self) -> ShouldRun<'a> {
 309         self.paths.insert(PathSet::empty());
 310         self
 311     }
 312
 313     fn pathset_for_path(&self, path: &Path) -> Option<&PathSet> {
 314         self.paths.iter().find(|pathset| pathset.has(path))
 315     }
 316 }
 317
 318 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 319 pub enum Kind {
 320     Build,
 321     Check,
 322     Clippy,
 323     Fix,
 324     Test,
 325     Bench,
 326     Dist,
 327     Doc,
 328     Install,
 329 }
 330
 331 impl<'a> Builder<'a> {
 332     fn get_step_descriptions(kind: Kind) -> Vec<StepDescription> {
 333         macro_rules! describe {
 334             ($($rule:ty),+ $(,)?) => {{
 335                 vec![$(StepDescription::from::<$rule>()),+]
 336             }};
 337         }
 338         match kind {
 339             Kind::Build => describe!(
 340                 compile::Std,
 341                 compile::Rustc,
 342                 compile::StartupObjects,
 343                 tool::BuildManifest,
 344                 tool::Rustbook,
 345                 tool::ErrorIndex,
 346                 tool::UnstableBookGen,
 347                 tool::Tidy,
 348                 tool::Linkchecker,
 349                 tool::CargoTest,
 350                 tool::Compiletest,
 351                 tool::RemoteTestServer,
 352                 tool::RemoteTestClient,
 353                 tool::RustInstaller,
 354                 tool::Cargo,
 355                 tool::Rls,
 356                 tool::Rustdoc,
 357                 tool::Clippy,
 358                 native::Llvm,
 359                 tool::Rustfmt,
 360                 tool::Miri,
 361                 native::Lld
 362             ),
 363             Kind::Check | Kind::Clippy | Kind::Fix => describe!(
 364                 check::Std,
 365                 check::Rustc,
 366                 check::Rustdoc
 367             ),
 368             Kind::Test => describe!(
 369                 crate::toolstate::ToolStateCheck,
 370                 test::Tidy,
 371                 test::Ui,
 372                 test::CompileFail,
 373                 test::RunFail,
 374                 test::RunPassValgrind,
 375                 test::MirOpt,
 376                 test::Codegen,
 377                 test::CodegenUnits,
 378                 test::Assembly,
 379                 test::Incremental,
 380                 test::Debuginfo,
 381                 test::UiFullDeps,
 382                 test::Rustdoc,
 383                 test::Pretty,
 384                 test::RunFailPretty,
 385                 test::RunPassValgrindPretty,
 386                 test::Crate,
 387                 test::CrateLibrustc,
 388                 test::CrateRustdoc,
 389                 test::Linkcheck,
 390                 test::Cargotest,
 391                 test::Cargo,
 392                 test::Rls,
 393                 test::ErrorIndex,
 394                 test::Distcheck,
 395                 test::RunMakeFullDeps,
 396                 test::Nomicon,
 397                 test::Reference,
 398                 test::RustdocBook,
 399                 test::RustByExample,
 400                 test::TheBook,
 401                 test::UnstableBook,
 402                 test::RustcBook,
 403                 test::RustcGuide,
 404                 test::EmbeddedBook,
 405                 test::EditionGuide,
 406                 test::Rustfmt,
 407                 test::Miri,
 408                 test::Clippy,
 409                 test::CompiletestTest,
 410                 test::RustdocJSStd,
 411                 test::RustdocJSNotStd,
 412                 test::RustdocTheme,
 413                 test::RustdocUi,
 414                 // Run bootstrap close to the end as it's unlikely to fail
 415                 test::Bootstrap,
 416                 // Run run-make last, since these won't pass without make on Windows
 417                 test::RunMake,
 418             ),
 419             Kind::Bench => describe!(test::Crate, test::CrateLibrustc),
 420             Kind::Doc => describe!(
 421                 doc::UnstableBook,
 422                 doc::UnstableBookGen,
 423                 doc::TheBook,
 424                 doc::Standalone,
 425                 doc::Std,
 426                 doc::Rustc,
 427                 doc::Rustdoc,
 428                 doc::ErrorIndex,
 429                 doc::Nomicon,
 430                 doc::Reference,
 431                 doc::RustdocBook,
 432                 doc::RustByExample,
 433                 doc::RustcBook,
 434                 doc::CargoBook,
 435                 doc::EmbeddedBook,
 436                 doc::EditionGuide,
 437             ),
 438             Kind::Dist => describe!(
 439                 dist::Docs,
 440                 dist::RustcDocs,
 441                 dist::Mingw,
 442                 dist::Rustc,
 443                 dist::DebuggerScripts,
 444                 dist::Std,
 445                 dist::RustcDev,
 446                 dist::Analysis,
 447                 dist::Src,
 448                 dist::PlainSourceTarball,
 449                 dist::Cargo,
 450                 dist::Rls,
 451                 dist::Rustfmt,
 452                 dist::Clippy,
 453                 dist::Miri,
 454                 dist::LlvmTools,
 455                 dist::Lldb,
 456                 dist::Extended,
 457                 dist::HashSign
 458             ),
 459             Kind::Install => describe!(
 460                 install::Docs,
 461                 install::Std,
 462                 install::Cargo,
 463                 install::Rls,
 464                 install::Rustfmt,
 465                 install::Clippy,
 466                 install::Miri,
 467                 install::Analysis,
 468                 install::Src,
 469                 install::Rustc
 470             ),
 471         }
 472     }
 473
 474     pub fn get_help(build: &Build, subcommand: &str) -> Option<String> {
 475         let kind = match subcommand {
 476             "build" => Kind::Build,
 477             "doc" => Kind::Doc,
 478             "test" => Kind::Test,
 479             "bench" => Kind::Bench,
 480             "dist" => Kind::Dist,
 481             "install" => Kind::Install,
 482             _ => return None,
 483         };
 484
 485         let builder = Builder {
 486             build,
 487             top_stage: build.config.stage.unwrap_or(2),
 488             kind,
 489             cache: Cache::new(),
 490             stack: RefCell::new(Vec::new()),
 491             time_spent_on_dependencies: Cell::new(Duration::new(0, 0)),
 492             paths: vec![],
 493             graph_nodes: RefCell::new(HashMap::new()),
 494             graph: RefCell::new(Graph::new()),
 495             parent: Cell::new(None),
 496         };
 497
 498         let builder = &builder;
 499         let mut should_run = ShouldRun::new(builder);
 500         for desc in Builder::get_step_descriptions(builder.kind) {
 501             should_run = (desc.should_run)(should_run);
 502         }
 503         let mut help = String::from("Available paths:\n");
 504         for pathset in should_run.paths {
 505             if let PathSet::Set(set) = pathset {
 506                 set.iter().for_each(|path| {
 507                     help.push_str(
 508                         format!("    ./x.py {} {}\n", subcommand, path.display()).as_str(),
 509                     )
 510                 })
 511             }
 512         }
 513         Some(help)
 514     }
 515
 516     pub fn new(build: &Build) -> Builder<'_> {
 517         let (kind, paths) = match build.config.cmd {
 518             Subcommand::Build { ref paths } => (Kind::Build, &paths[..]),
 519             Subcommand::Check { ref paths } => (Kind::Check, &paths[..]),
 520             Subcommand::Clippy { ref paths } => (Kind::Clippy, &paths[..]),
 521             Subcommand::Fix { ref paths } => (Kind::Fix, &paths[..]),
 522             Subcommand::Doc { ref paths } => (Kind::Doc, &paths[..]),
 523             Subcommand::Test { ref paths, .. } => (Kind::Test, &paths[..]),
 524             Subcommand::Bench { ref paths, .. } => (Kind::Bench, &paths[..]),
 525             Subcommand::Dist { ref paths } => (Kind::Dist, &paths[..]),
 526             Subcommand::Install { ref paths } => (Kind::Install, &paths[..]),
 527             Subcommand::Clean { .. } => panic!(),
 528         };
 529
 530         let builder = Builder {
 531             build,
 532             top_stage: build.config.stage.unwrap_or(2),
 533             kind,
 534             cache: Cache::new(),
 535             stack: RefCell::new(Vec::new()),
 536             time_spent_on_dependencies: Cell::new(Duration::new(0, 0)),
 537             paths: paths.to_owned(),
 538             graph_nodes: RefCell::new(HashMap::new()),
 539             graph: RefCell::new(Graph::new()),
 540             parent: Cell::new(None),
 541         };
 542
 543         builder
 544     }
 545
 546     pub fn execute_cli(&self) -> Graph<String, bool> {
 547         self.run_step_descriptions(&Builder::get_step_descriptions(self.kind), &self.paths);
 548         self.graph.borrow().clone()
 549     }
 550
 551     pub fn default_doc(&self, paths: Option<&[PathBuf]>) {
 552         let paths = paths.unwrap_or(&[]);
 553         self.run_step_descriptions(&Builder::get_step_descriptions(Kind::Doc), paths);
 554     }
 555
 556     fn run_step_descriptions(&self, v: &[StepDescription], paths: &[PathBuf]) {
 557         StepDescription::run(v, self, paths);
 558     }
 559
 560     /// Obtain a compiler at a given stage and for a given host. Explicitly does
 561     /// not take `Compiler` since all `Compiler` instances are meant to be
 562     /// obtained through this function, since it ensures that they are valid
 563     /// (i.e., built and assembled).
 564     pub fn compiler(&self, stage: u32, host: Interned<String>) -> Compiler {
 565         self.ensure(compile::Assemble {
 566             target_compiler: Compiler { stage, host },
 567         })
 568     }
 569
 570     /// Similar to `compiler`, except handles the full-bootstrap option to
 571     /// silently use the stage1 compiler instead of a stage2 compiler if one is
 572     /// requested.
 573     ///
 574     /// Note that this does *not* have the side effect of creating
 575     /// `compiler(stage, host)`, unlike `compiler` above which does have such
 576     /// a side effect. The returned compiler here can only be used to compile
 577     /// new artifacts, it can't be used to rely on the presence of a particular
 578     /// sysroot.
 579     ///
 580     /// See `force_use_stage1` for documentation on what each argument is.
 581     pub fn compiler_for(
 582         &self,
 583         stage: u32,
 584         host: Interned<String>,
 585         target: Interned<String>,
 586     ) -> Compiler {
 587         if self.build.force_use_stage1(Compiler { stage, host }, target) {
 588             self.compiler(1, self.config.build)
 589         } else {
 590             self.compiler(stage, host)
 591         }
 592     }
 593
 594     pub fn sysroot(&self, compiler: Compiler) -> Interned<PathBuf> {
 595         self.ensure(compile::Sysroot { compiler })
 596     }
 597
 598     /// Returns the libdir where the standard library and other artifacts are
 599     /// found for a compiler's sysroot.
 600     pub fn sysroot_libdir(
 601         &self,
 602         compiler: Compiler,
 603         target: Interned<String>,
 604     ) -> Interned<PathBuf> {
 605         #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 606         struct Libdir {
 607             compiler: Compiler,
 608             target: Interned<String>,
 609         }
 610         impl Step for Libdir {
 611             type Output = Interned<PathBuf>;
 612
 613             fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
 614                 run.never()
 615             }
 616
 617             fn run(self, builder: &Builder<'_>) -> Interned<PathBuf> {
 618                 let lib = builder.sysroot_libdir_relative(self.compiler);
 619                 let sysroot = builder
 620                     .sysroot(self.compiler)
 621                     .join(lib)
 622                     .join("rustlib")
 623                     .join(self.target)
 624                     .join("lib");
 625                 let _ = fs::remove_dir_all(&sysroot);
 626                 t!(fs::create_dir_all(&sysroot));
 627                 INTERNER.intern_path(sysroot)
 628             }
 629         }
 630         self.ensure(Libdir { compiler, target })
 631     }
 632
 633     /// Returns the compiler's libdir where it stores the dynamic libraries that
 634     /// it itself links against.
 635     ///
 636     /// For example this returns `<sysroot>/lib` on Unix and `<sysroot>/bin` on
 637     /// Windows.
 638     pub fn rustc_libdir(&self, compiler: Compiler) -> PathBuf {
 639         if compiler.is_snapshot(self) {
 640             self.rustc_snapshot_libdir()
 641         } else {
 642             match self.config.libdir_relative() {
 643                 Some(relative_libdir) if compiler.stage >= 1
 644                     => self.sysroot(compiler).join(relative_libdir),
 645                 _ => self.sysroot(compiler).join(libdir(&compiler.host))
 646             }
 647         }
 648     }
 649
 650     /// Returns the compiler's relative libdir where it stores the dynamic libraries that
 651     /// it itself links against.
 652     ///
 653     /// For example this returns `lib` on Unix and `bin` on
 654     /// Windows.
 655     pub fn libdir_relative(&self, compiler: Compiler) -> &Path {
 656         if compiler.is_snapshot(self) {
 657             libdir(&self.config.build).as_ref()
 658         } else {
 659             match self.config.libdir_relative() {
 660                 Some(relative_libdir) if compiler.stage >= 1
 661                     => relative_libdir,
 662                 _ => libdir(&compiler.host).as_ref()
 663             }
 664         }
 665     }
 666
 667     /// Returns the compiler's relative libdir where the standard library and other artifacts are
 668     /// found for a compiler's sysroot.
 669     ///
 670     /// For example this returns `lib` on Unix and Windows.
 671     pub fn sysroot_libdir_relative(&self, compiler: Compiler) -> &Path {
 672         match self.config.libdir_relative() {
 673             Some(relative_libdir) if compiler.stage >= 1
 674                 => relative_libdir,
 675             _ => Path::new("lib")
 676         }
 677     }
 678
 679     /// Adds the compiler's directory of dynamic libraries to `cmd`'s dynamic
 680     /// library lookup path.
 681     pub fn add_rustc_lib_path(&self, compiler: Compiler, cmd: &mut Cargo) {
 682         // Windows doesn't need dylib path munging because the dlls for the
 683         // compiler live next to the compiler and the system will find them
 684         // automatically.
 685         if cfg!(windows) {
 686             return;
 687         }
 688
 689         add_lib_path(vec![self.rustc_libdir(compiler)], &mut cmd.command);
 690     }
 691
 692     /// Gets a path to the compiler specified.
 693     pub fn rustc(&self, compiler: Compiler) -> PathBuf {
 694         if compiler.is_snapshot(self) {
 695             self.initial_rustc.clone()
 696         } else {
 697             self.sysroot(compiler)
 698                 .join("bin")
 699                 .join(exe("rustc", &compiler.host))
 700         }
 701     }
 702
 703     pub fn rustdoc(&self, compiler: Compiler) -> PathBuf {
 704         self.ensure(tool::Rustdoc { compiler })
 705     }
 706
 707     pub fn rustdoc_cmd(&self, compiler: Compiler) -> Command {
 708         let mut cmd = Command::new(&self.out.join("bootstrap/debug/rustdoc"));
 709         cmd.env("RUSTC_STAGE", compiler.stage.to_string())
 710             .env("RUSTC_SYSROOT", self.sysroot(compiler))
 711             // Note that this is *not* the sysroot_libdir because rustdoc must be linked
 712             // equivalently to rustc.
 713             .env("RUSTDOC_LIBDIR", self.rustc_libdir(compiler))
 714             .env("CFG_RELEASE_CHANNEL", &self.config.channel)
 715             .env("RUSTDOC_REAL", self.rustdoc(compiler))
 716             .env("RUSTDOC_CRATE_VERSION", self.rust_version())
 717             .env("RUSTC_BOOTSTRAP", "1");
 718
 719         // Remove make-related flags that can cause jobserver problems.
 720         cmd.env_remove("MAKEFLAGS");
 721         cmd.env_remove("MFLAGS");
 722
 723         if let Some(linker) = self.linker(compiler.host) {
 724             cmd.env("RUSTC_TARGET_LINKER", linker);
 725         }
 726         cmd
 727     }
 728
 729     /// Prepares an invocation of `cargo` to be run.
 730     ///
 731     /// This will create a `Command` that represents a pending execution of
 732     /// Cargo. This cargo will be configured to use `compiler` as the actual
 733     /// rustc compiler, its output will be scoped by `mode`'s output directory,
 734     /// it will pass the `--target` flag for the specified `target`, and will be
 735     /// executing the Cargo command `cmd`.
 736     pub fn cargo(
 737         &self,
 738         compiler: Compiler,
 739         mode: Mode,
 740         target: Interned<String>,
 741         cmd: &str,
 742     ) -> Cargo {
 743         let mut cargo = Command::new(&self.initial_cargo);
 744         let out_dir = self.stage_out(compiler, mode);
 745
 746         if cmd == "doc" || cmd == "rustdoc" {
 747             let my_out = match mode {
 748                 // This is the intended out directory for compiler documentation.
 749                 Mode::Rustc | Mode::ToolRustc | Mode::Codegen => self.compiler_doc_out(target),
 750                 _ => self.crate_doc_out(target),
 751             };
 752             let rustdoc = self.rustdoc(compiler);
 753             self.clear_if_dirty(&my_out, &rustdoc);
 754         }
 755
 756         cargo
 757             .env("CARGO_TARGET_DIR", out_dir)
 758             .arg(cmd)
 759             .arg("-Zconfig-profile");
 760
 761         let profile_var = |name: &str| {
 762             let profile = if self.config.rust_optimize {
 763                 "RELEASE"
 764             } else {
 765                 "DEV"
 766             };
 767             format!("CARGO_PROFILE_{}_{}", profile, name)
 768         };
 769
 770         // See comment in librustc_llvm/build.rs for why this is necessary, largely llvm-config
 771         // needs to not accidentally link to libLLVM in stage0/lib.
 772         cargo.env("REAL_LIBRARY_PATH_VAR", &util::dylib_path_var());
 773         if let Some(e) = env::var_os(util::dylib_path_var()) {
 774             cargo.env("REAL_LIBRARY_PATH", e);
 775         }
 776
 777         if cmd != "install" {
 778             cargo.arg("--target")
 779                  .arg(target);
 780         } else {
 781             assert_eq!(target, compiler.host);
 782         }
 783
 784         // Set a flag for `check`/`clippy`/`fix`, so that certain build
 785         // scripts can do less work (e.g. not building/requiring LLVM).
 786         if cmd == "check" || cmd == "clippy" || cmd == "fix" {
 787             cargo.env("RUST_CHECK", "1");
 788         }
 789
 790         let stage;
 791         if compiler.stage == 0 && self.local_rebuild {
 792             // Assume the local-rebuild rustc already has stage1 features.
 793             stage = 1;
 794         } else {
 795             stage = compiler.stage;
 796         }
 797
 798         let mut rustflags = Rustflags::new(&target);
 799         if stage != 0 {
 800             if let Ok(s) = env::var("CARGOFLAGS_NOT_BOOTSTRAP") {
 801                 cargo.args(s.split_whitespace());
 802             }
 803             rustflags.env("RUSTFLAGS_NOT_BOOTSTRAP");
 804         } else {
 805             if let Ok(s) = env::var("CARGOFLAGS_BOOTSTRAP") {
 806                 cargo.args(s.split_whitespace());
 807             }
 808             rustflags.env("RUSTFLAGS_BOOTSTRAP");
 809             rustflags.arg("--cfg=bootstrap");
 810         }
 811
 812         if let Ok(s) = env::var("CARGOFLAGS") {
 813             cargo.args(s.split_whitespace());
 814         }
 815
 816         match mode {
 817             Mode::Std | Mode::ToolBootstrap | Mode::ToolStd => {},
 818             Mode::Rustc | Mode::Codegen | Mode::ToolRustc => {
 819                 // Build proc macros both for the host and the target
 820                 if target != compiler.host && cmd != "check" {
 821                     cargo.arg("-Zdual-proc-macros");
 822                     rustflags.arg("-Zdual-proc-macros");
 823                 }
 824             },
 825         }
 826
 827         // This tells Cargo (and in turn, rustc) to output more complete
 828         // dependency information.  Most importantly for rustbuild, this
 829         // includes sysroot artifacts, like libstd, which means that we don't
 830         // need to track those in rustbuild (an error prone process!). This
 831         // feature is currently unstable as there may be some bugs and such, but
 832         // it represents a big improvement in rustbuild's reliability on
 833         // rebuilds, so we're using it here.
 834         //
 835         // For some additional context, see #63470 (the PR originally adding
 836         // this), as well as #63012 which is the tracking issue for this
 837         // feature on the rustc side.
 838         cargo.arg("-Zbinary-dep-depinfo");
 839
 840         cargo.arg("-j").arg(self.jobs().to_string());
 841         // Remove make-related flags to ensure Cargo can correctly set things up
 842         cargo.env_remove("MAKEFLAGS");
 843         cargo.env_remove("MFLAGS");
 844
 845         // FIXME: Temporary fix for https://github.com/rust-lang/cargo/issues/3005
 846         // Force cargo to output binaries with disambiguating hashes in the name
 847         let mut metadata = if compiler.stage == 0 {
 848             // Treat stage0 like a special channel, whether it's a normal prior-
 849             // release rustc or a local rebuild with the same version, so we
 850             // never mix these libraries by accident.
 851             "bootstrap".to_string()
 852         } else {
 853             self.config.channel.to_string()
 854         };
 855         // We want to make sure that none of the dependencies between
 856         // std/test/rustc unify with one another. This is done for weird linkage
 857         // reasons but the gist of the problem is that if librustc, libtest, and
 858         // libstd all depend on libc from crates.io (which they actually do) we
 859         // want to make sure they all get distinct versions. Things get really
 860         // weird if we try to unify all these dependencies right now, namely
 861         // around how many times the library is linked in dynamic libraries and
 862         // such. If rustc were a static executable or if we didn't ship dylibs
 863         // this wouldn't be a problem, but we do, so it is. This is in general
 864         // just here to make sure things build right. If you can remove this and
 865         // things still build right, please do!
 866         match mode {
 867             Mode::Std => metadata.push_str("std"),
 868             // When we're building rustc tools, they're built with a search path
 869             // that contains things built during the rustc build. For example,
 870             // bitflags is built during the rustc build, and is a dependency of
 871             // rustdoc as well. We're building rustdoc in a different target
 872             // directory, though, which means that Cargo will rebuild the
 873             // dependency. When we go on to build rustdoc, we'll look for
 874             // bitflags, and find two different copies: one built during the
 875             // rustc step and one that we just built. This isn't always a
 876             // problem, somehow -- not really clear why -- but we know that this
 877             // fixes things.
 878             Mode::ToolRustc => metadata.push_str("tool-rustc"),
 879             _ => {}
 880         }
 881         cargo.env("__CARGO_DEFAULT_LIB_METADATA", &metadata);
 882
 883         if cmd == "clippy" {
 884             rustflags.arg("-Zforce-unstable-if-unmarked");
 885         }
 886
 887         rustflags.arg("-Zexternal-macro-backtrace");
 888
 889         let want_rustdoc = self.doc_tests != DocTests::No;
 890
 891         // We synthetically interpret a stage0 compiler used to build tools as a
 892         // "raw" compiler in that it's the exact snapshot we download. Normally
 893         // the stage0 build means it uses libraries build by the stage0
 894         // compiler, but for tools we just use the precompiled libraries that
 895         // we've downloaded
 896         let use_snapshot = mode == Mode::ToolBootstrap;
 897         assert!(!use_snapshot || stage == 0 || self.local_rebuild);
 898
 899         let maybe_sysroot = self.sysroot(compiler);
 900         let sysroot = if use_snapshot {
 901             self.rustc_snapshot_sysroot()
 902         } else {
 903             &maybe_sysroot
 904         };
 905         let libdir = self.rustc_libdir(compiler);
 906
 907         // Customize the compiler we're running. Specify the compiler to cargo
 908         // as our shim and then pass it some various options used to configure
 909         // how the actual compiler itself is called.
 910         //
 911         // These variables are primarily all read by
 912         // src/bootstrap/bin/{rustc.rs,rustdoc.rs}
 913         cargo
 914             .env("RUSTBUILD_NATIVE_DIR", self.native_dir(target))
 915             .env("RUSTC", self.out.join("bootstrap/debug/rustc"))
 916             .env("RUSTC_REAL", self.rustc(compiler))
 917             .env("RUSTC_STAGE", stage.to_string())
 918             .env(
 919                 "RUSTC_DEBUG_ASSERTIONS",
 920                 self.config.rust_debug_assertions.to_string(),
 921             )
 922             .env("RUSTC_SYSROOT", &sysroot)
 923             .env("RUSTC_LIBDIR", &libdir)
 924             .env("RUSTDOC", self.out.join("bootstrap/debug/rustdoc"))
 925             .env(
 926                 "RUSTDOC_REAL",
 927                 if cmd == "doc" || cmd == "rustdoc" || (cmd == "test" && want_rustdoc) {
 928                     self.rustdoc(compiler)
 929                 } else {
 930                     PathBuf::from("/path/to/nowhere/rustdoc/not/required")
 931                 },
 932             )
 933             .env("RUSTC_ERROR_METADATA_DST", self.extended_error_dir())
 934             .env("RUSTC_BREAK_ON_ICE", "1");
 935
 936         // Dealing with rpath here is a little special, so let's go into some
 937         // detail. First off, `-rpath` is a linker option on Unix platforms
 938         // which adds to the runtime dynamic loader path when looking for
 939         // dynamic libraries. We use this by default on Unix platforms to ensure
 940         // that our nightlies behave the same on Windows, that is they work out
 941         // of the box. This can be disabled, of course, but basically that's why
 942         // we're gated on RUSTC_RPATH here.
 943         //
 944         // Ok, so the astute might be wondering "why isn't `-C rpath` used
 945         // here?" and that is indeed a good question to task. This codegen
 946         // option is the compiler's current interface to generating an rpath.
 947         // Unfortunately it doesn't quite suffice for us. The flag currently
 948         // takes no value as an argument, so the compiler calculates what it
 949         // should pass to the linker as `-rpath`. This unfortunately is based on
 950         // the **compile time** directory structure which when building with
 951         // Cargo will be very different than the runtime directory structure.
 952         //
 953         // All that's a really long winded way of saying that if we use
 954         // `-Crpath` then the executables generated have the wrong rpath of
 955         // something like `$ORIGIN/deps` when in fact the way we distribute
 956         // rustc requires the rpath to be `$ORIGIN/../lib`.
 957         //
 958         // So, all in all, to set up the correct rpath we pass the linker
 959         // argument manually via `-C link-args=-Wl,-rpath,...`. Plus isn't it
 960         // fun to pass a flag to a tool to pass a flag to pass a flag to a tool
 961         // to change a flag in a binary?
 962         if self.config.rust_rpath && util::use_host_linker(&target) {
 963             let rpath = if target.contains("apple") {
 964
 965                 // Note that we need to take one extra step on macOS to also pass
 966                 // `-Wl,-instal_name,@rpath/...` to get things to work right. To
 967                 // do that we pass a weird flag to the compiler to get it to do
 968                 // so. Note that this is definitely a hack, and we should likely
 969                 // flesh out rpath support more fully in the future.
 970                 rustflags.arg("-Zosx-rpath-install-name");
 971                 Some("-Wl,-rpath,@loader_path/../lib")
 972             } else if !target.contains("windows") {
 973                 Some("-Wl,-rpath,$ORIGIN/../lib")
 974             } else {
 975                 None
 976             };
 977             if let Some(rpath) = rpath {
 978                 rustflags.arg(&format!("-Clink-args={}", rpath));
 979             }
 980         }
 981
 982         if let Some(host_linker) = self.linker(compiler.host) {
 983             cargo.env("RUSTC_HOST_LINKER", host_linker);
 984         }
 985         if let Some(target_linker) = self.linker(target) {
 986             let target = crate::envify(&target);
 987             cargo.env(&format!("CARGO_TARGET_{}_LINKER", target), target_linker);
 988         }
 989         if !(["build", "check", "clippy", "fix", "rustc"].contains(&cmd)) && want_rustdoc {
 990             cargo.env("RUSTDOC_LIBDIR", self.rustc_libdir(compiler));
 991         }
 992
 993         let debuginfo_level = match mode {
 994             Mode::Rustc | Mode::Codegen => self.config.rust_debuginfo_level_rustc,
 995             Mode::Std => self.config.rust_debuginfo_level_std,
 996             Mode::ToolBootstrap | Mode::ToolStd |
 997             Mode::ToolRustc => self.config.rust_debuginfo_level_tools,
 998         };
 999         cargo.env(profile_var("DEBUG"), debuginfo_level.to_string());
1000
1001         if !mode.is_tool() {
1002             cargo.env("RUSTC_FORCE_UNSTABLE", "1");
1003         }
1004
1005         if let Some(x) = self.crt_static(target) {
1006             if x {
1007                 rustflags.arg("-Ctarget-feature=+crt-static");
1008             } else {
1009                 rustflags.arg("-Ctarget-feature=-crt-static");
1010             }
1011         }
1012
1013         if let Some(x) = self.crt_static(compiler.host) {
1014             cargo.env("RUSTC_HOST_CRT_STATIC", x.to_string());
1015         }
1016
1017         if let Some(map) = self.build.debuginfo_map(GitRepo::Rustc) {
1018             cargo.env("RUSTC_DEBUGINFO_MAP", map);
1019         }
1020
1021         // Enable usage of unstable features
1022         cargo.env("RUSTC_BOOTSTRAP", "1");
1023         self.add_rust_test_threads(&mut cargo);
1024
1025         // Almost all of the crates that we compile as part of the bootstrap may
1026         // have a build script, including the standard library. To compile a
1027         // build script, however, it itself needs a standard library! This
1028         // introduces a bit of a pickle when we're compiling the standard
1029         // library itself.
1030         //
1031         // To work around this we actually end up using the snapshot compiler
1032         // (stage0) for compiling build scripts of the standard library itself.
1033         // The stage0 compiler is guaranteed to have a libstd available for use.
1034         //
1035         // For other crates, however, we know that we've already got a standard
1036         // library up and running, so we can use the normal compiler to compile
1037         // build scripts in that situation.
1038         if mode == Mode::Std {
1039             cargo
1040                 .env("RUSTC_SNAPSHOT", &self.initial_rustc)
1041                 .env("RUSTC_SNAPSHOT_LIBDIR", self.rustc_snapshot_libdir());
1042         } else {
1043             cargo
1044                 .env("RUSTC_SNAPSHOT", self.rustc(compiler))
1045                 .env("RUSTC_SNAPSHOT_LIBDIR", self.rustc_libdir(compiler));
1046         }
1047
1048         if self.config.incremental {
1049             cargo.env("CARGO_INCREMENTAL", "1");
1050         } else {
1051             // Don't rely on any default setting for incr. comp. in Cargo
1052             cargo.env("CARGO_INCREMENTAL", "0");
1053         }
1054
1055         if let Some(ref on_fail) = self.config.on_fail {
1056             cargo.env("RUSTC_ON_FAIL", on_fail);
1057         }
1058
1059         if self.config.print_step_timings {
1060             cargo.env("RUSTC_PRINT_STEP_TIMINGS", "1");
1061         }
1062
1063         if self.config.backtrace_on_ice {
1064             cargo.env("RUSTC_BACKTRACE_ON_ICE", "1");
1065         }
1066
1067         cargo.env("RUSTC_VERBOSE", self.verbosity.to_string());
1068
1069         if !mode.is_tool() {
1070             // When extending this list, add the new lints to the RUSTFLAGS of the
1071             // build_bootstrap function of src/bootstrap/bootstrap.py as well as
1072             // some code doesn't go through this `rustc` wrapper.
1073             rustflags.arg("-Wrust_2018_idioms");
1074             rustflags.arg("-Wunused_lifetimes");
1075
1076             if self.config.deny_warnings {
1077                 rustflags.arg("-Dwarnings");
1078             }
1079         }
1080
1081         if let Mode::Rustc | Mode::Codegen = mode {
1082             rustflags.arg("-Zunstable-options");
1083             rustflags.arg("-Wrustc::internal");
1084         }
1085
1086         // Throughout the build Cargo can execute a number of build scripts
1087         // compiling C/C++ code and we need to pass compilers, archivers, flags, etc
1088         // obtained previously to those build scripts.
1089         // Build scripts use either the `cc` crate or `configure/make` so we pass
1090         // the options through environment variables that are fetched and understood by both.
1091         //
1092         // FIXME: the guard against msvc shouldn't need to be here
1093         if target.contains("msvc") {
1094             if let Some(ref cl) = self.config.llvm_clang_cl {
1095                 cargo.env("CC", cl).env("CXX", cl);
1096             }
1097         } else {
1098             let ccache = self.config.ccache.as_ref();
1099             let ccacheify = |s: &Path| {
1100                 let ccache = match ccache {
1101                     Some(ref s) => s,
1102                     None => return s.display().to_string(),
1103                 };
1104                 // FIXME: the cc-rs crate only recognizes the literal strings
1105                 // `ccache` and `sccache` when doing caching compilations, so we
1106                 // mirror that here. It should probably be fixed upstream to
1107                 // accept a new env var or otherwise work with custom ccache
1108                 // vars.
1109                 match &ccache[..] {
1110                     "ccache" | "sccache" => format!("{} {}", ccache, s.display()),
1111                     _ => s.display().to_string(),
1112                 }
1113             };
1114             let cc = ccacheify(&self.cc(target));
1115             cargo.env(format!("CC_{}", target), &cc);
1116
1117             let cflags = self.cflags(target, GitRepo::Rustc).join(" ");
1118             cargo
1119                 .env(format!("CFLAGS_{}", target), cflags.clone());
1120
1121             if let Some(ar) = self.ar(target) {
1122                 let ranlib = format!("{} s", ar.display());
1123                 cargo
1124                     .env(format!("AR_{}", target), ar)
1125                     .env(format!("RANLIB_{}", target), ranlib);
1126             }
1127
1128             if let Ok(cxx) = self.cxx(target) {
1129                 let cxx = ccacheify(&cxx);
1130                 cargo
1131                     .env(format!("CXX_{}", target), &cxx)
1132                     .env(format!("CXXFLAGS_{}", target), cflags);
1133             }
1134         }
1135
1136         if mode == Mode::Std
1137             && self.config.extended
1138             && compiler.is_final_stage(self)
1139         {
1140             rustflags.arg("-Zsave-analysis");
1141             cargo.env("RUST_SAVE_ANALYSIS_CONFIG",
1142                       "{\"output_file\": null,\"full_docs\": false,\
1143                        \"pub_only\": true,\"reachable_only\": false,\
1144                        \"distro_crate\": true,\"signatures\": false,\"borrow_data\": false}");
1145         }
1146
1147         // For `cargo doc` invocations, make rustdoc print the Rust version into the docs
1148         cargo.env("RUSTDOC_CRATE_VERSION", self.rust_version());
1149
1150         // Environment variables *required* throughout the build
1151         //
1152         // FIXME: should update code to not require this env var
1153         cargo.env("CFG_COMPILER_HOST_TRIPLE", target);
1154
1155         // Set this for all builds to make sure doc builds also get it.
1156         cargo.env("CFG_RELEASE_CHANNEL", &self.config.channel);
1157
1158         // This one's a bit tricky. As of the time of this writing the compiler
1159         // links to the `winapi` crate on crates.io. This crate provides raw
1160         // bindings to Windows system functions, sort of like libc does for
1161         // Unix. This crate also, however, provides "import libraries" for the
1162         // MinGW targets. There's an import library per dll in the windows
1163         // distribution which is what's linked to. These custom import libraries
1164         // are used because the winapi crate can reference Windows functions not
1165         // present in the MinGW import libraries.
1166         //
1167         // For example MinGW may ship libdbghelp.a, but it may not have
1168         // references to all the functions in the dbghelp dll. Instead the
1169         // custom import library for dbghelp in the winapi crates has all this
1170         // information.
1171         //
1172         // Unfortunately for us though the import libraries are linked by
1173         // default via `-ldylib=winapi_foo`. That is, they're linked with the
1174         // `dylib` type with a `winapi_` prefix (so the winapi ones don't
1175         // conflict with the system MinGW ones). This consequently means that
1176         // the binaries we ship of things like rustc_codegen_llvm (aka the rustc_codegen_llvm
1177         // DLL) when linked against *again*, for example with procedural macros
1178         // or plugins, will trigger the propagation logic of `-ldylib`, passing
1179         // `-lwinapi_foo` to the linker again. This isn't actually available in
1180         // our distribution, however, so the link fails.
1181         //
1182         // To solve this problem we tell winapi to not use its bundled import
1183         // libraries. This means that it will link to the system MinGW import
1184         // libraries by default, and the `-ldylib=foo` directives will still get
1185         // passed to the final linker, but they'll look like `-lfoo` which can
1186         // be resolved because MinGW has the import library. The downside is we
1187         // don't get newer functions from Windows, but we don't use any of them
1188         // anyway.
1189         if !mode.is_tool() {
1190             cargo.env("WINAPI_NO_BUNDLED_LIBRARIES", "1");
1191         }
1192
1193         for _ in 1..self.verbosity {
1194             cargo.arg("-v");
1195         }
1196
1197         match (mode, self.config.rust_codegen_units_std, self.config.rust_codegen_units) {
1198             (Mode::Std, Some(n), _) |
1199             (_, _, Some(n)) => {
1200                 cargo.env(profile_var("CODEGEN_UNITS"), n.to_string());
1201             }
1202             _ => {
1203                 // Don't set anything
1204             }
1205         }
1206
1207         if self.config.rust_optimize {
1208             // FIXME: cargo bench/install do not accept `--release`
1209             if cmd != "bench" && cmd != "install" {
1210                 cargo.arg("--release");
1211             }
1212         }
1213
1214         if self.config.locked_deps {
1215             cargo.arg("--locked");
1216         }
1217         if self.config.vendor || self.is_sudo {
1218             cargo.arg("--frozen");
1219         }
1220
1221         // Try to use a sysroot-relative bindir, in case it was configured absolutely.
1222         cargo.env("RUSTC_INSTALL_BINDIR", self.config.bindir_relative());
1223
1224         self.ci_env.force_coloring_in_ci(&mut cargo);
1225
1226         // When we build Rust dylibs they're all intended for intermediate
1227         // usage, so make sure we pass the -Cprefer-dynamic flag instead of
1228         // linking all deps statically into the dylib.
1229         if let Mode::Std | Mode::Rustc | Mode::Codegen = mode {
1230             rustflags.arg("-Cprefer-dynamic");
1231         }
1232
1233         Cargo {
1234             command: cargo,
1235             rustflags,
1236         }
1237     }
1238
1239     /// Ensure that a given step is built, returning its output. This will
1240     /// cache the step, so it is safe (and good!) to call this as often as
1241     /// needed to ensure that all dependencies are built.
1242     pub fn ensure<S: Step>(&'a self, step: S) -> S::Output {
1243         {
1244             let mut stack = self.stack.borrow_mut();
1245             for stack_step in stack.iter() {
1246                 // should skip
1247                 if stack_step
1248                     .downcast_ref::<S>()
1249                     .map_or(true, |stack_step| *stack_step != step)
1250                 {
1251                     continue;
1252                 }
1253                 let mut out = String::new();
1254                 out += &format!("\n\nCycle in build detected when adding {:?}\n", step);
1255                 for el in stack.iter().rev() {
1256                     out += &format!("\t{:?}\n", el);
1257                 }
1258                 panic!(out);
1259             }
1260             if let Some(out) = self.cache.get(&step) {
1261                 self.verbose(&format!("{}c {:?}", "  ".repeat(stack.len()), step));
1262
1263                 {
1264                     let mut graph = self.graph.borrow_mut();
1265                     let parent = self.parent.get();
1266                     let us = *self
1267                         .graph_nodes
1268                         .borrow_mut()
1269                         .entry(format!("{:?}", step))
1270                         .or_insert_with(|| graph.add_node(format!("{:?}", step)));
1271                     if let Some(parent) = parent {
1272                         graph.add_edge(parent, us, false);
1273                     }
1274                 }
1275
1276                 return out;
1277             }
1278             self.verbose(&format!("{}> {:?}", "  ".repeat(stack.len()), step));
1279             stack.push(Box::new(step.clone()));
1280         }
1281
1282         let prev_parent = self.parent.get();
1283
1284         {
1285             let mut graph = self.graph.borrow_mut();
1286             let parent = self.parent.get();
1287             let us = *self
1288                 .graph_nodes
1289                 .borrow_mut()
1290                 .entry(format!("{:?}", step))
1291                 .or_insert_with(|| graph.add_node(format!("{:?}", step)));
1292             self.parent.set(Some(us));
1293             if let Some(parent) = parent {
1294                 graph.add_edge(parent, us, true);
1295             }
1296         }
1297
1298         let (out, dur) = {
1299             let start = Instant::now();
1300             let zero = Duration::new(0, 0);
1301             let parent = self.time_spent_on_dependencies.replace(zero);
1302             let out = step.clone().run(self);
1303             let dur = start.elapsed();
1304             let deps = self.time_spent_on_dependencies.replace(parent + dur);
1305             (out, dur - deps)
1306         };
1307
1308         self.parent.set(prev_parent);
1309
1310         if self.config.print_step_timings && dur > Duration::from_millis(100) {
1311             println!(
1312                 "[TIMING] {:?} -- {}.{:03}",
1313                 step,
1314                 dur.as_secs(),
1315                 dur.subsec_nanos() / 1_000_000
1316             );
1317         }
1318
1319         {
1320             let mut stack = self.stack.borrow_mut();
1321             let cur_step = stack.pop().expect("step stack empty");
1322             assert_eq!(cur_step.downcast_ref(), Some(&step));
1323         }
1324         self.verbose(&format!(
1325             "{}< {:?}",
1326             "  ".repeat(self.stack.borrow().len()),
1327             step
1328         ));
1329         self.cache.put(step, out.clone());
1330         out
1331     }
1332 }
1333
1334 #[cfg(test)]
1335 mod tests;
1336
1337 #[derive(Debug)]
1338 struct Rustflags(String);
1339
1340 impl Rustflags {
1341     fn new(target: &str) -> Rustflags {
1342         let mut ret = Rustflags(String::new());
1343
1344         // Inherit `RUSTFLAGS` by default ...
1345         ret.env("RUSTFLAGS");
1346
1347         // ... and also handle target-specific env RUSTFLAGS if they're
1348         // configured.
1349         let target_specific = format!("CARGO_TARGET_{}_RUSTFLAGS", crate::envify(target));
1350         ret.env(&target_specific);
1351
1352         ret
1353     }
1354
1355     fn env(&mut self, env: &str) {
1356         if let Ok(s) = env::var(env) {
1357             for part in s.split_whitespace() {
1358                 self.arg(part);
1359             }
1360         }
1361     }
1362
1363     fn arg(&mut self, arg: &str) -> &mut Self {
1364         assert_eq!(arg.split_whitespace().count(), 1);
1365         if self.0.len() > 0 {
1366             self.0.push_str(" ");
1367         }
1368         self.0.push_str(arg);
1369         self
1370     }
1371 }
1372
1373 #[derive(Debug)]
1374 pub struct Cargo {
1375     command: Command,
1376     rustflags: Rustflags,
1377 }
1378
1379 impl Cargo {
1380     pub fn rustflag(&mut self, arg: &str) -> &mut Cargo {
1381         self.rustflags.arg(arg);
1382         self
1383     }
1384
1385     pub fn arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Cargo {
1386         self.command.arg(arg.as_ref());
1387         self
1388     }
1389
1390     pub fn args<I, S>(&mut self, args: I) -> &mut Cargo
1391         where I: IntoIterator<Item=S>, S: AsRef<OsStr>
1392     {
1393         for arg in args {
1394             self.arg(arg.as_ref());
1395         }
1396         self
1397     }
1398
1399     pub fn env(&mut self, key: impl AsRef<OsStr>, value: impl AsRef<OsStr>) -> &mut Cargo {
1400         self.command.env(key.as_ref(), value.as_ref());
1401         self
1402     }
1403 }
1404
1405 impl From<Cargo> for Command {
1406     fn from(mut cargo: Cargo) -> Command {
1407         cargo.command.env("RUSTFLAGS", &cargo.rustflags.0);
1408         cargo.command
1409     }
1410 }