1 use std::collections::HashSet;
4 use std::path::{Path, PathBuf};
5 use std::process::{exit, Command};
7 use crate::builder::{Builder, Cargo as CargoCommand, RunConfig, ShouldRun, Step};
8 use crate::channel::GitInfo;
10 use crate::config::TargetSelection;
11 use crate::toolstate::ToolState;
12 use crate::util::{add_dylib_path, exe, t};
16 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
22 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
25 target: TargetSelection,
29 is_optional_tool: bool,
30 source_type: SourceType,
31 extra_features: Vec<String>,
34 impl Step for ToolBuild {
35 type Output = Option<PathBuf>;
37 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
41 /// Builds a tool in `src/tools`
43 /// This will build the specified tool with the specified `host` compiler in
44 /// `stage` into the normal cargo output directory.
45 fn run(self, builder: &Builder<'_>) -> Option<PathBuf> {
46 let compiler = self.compiler;
47 let target = self.target;
48 let mut tool = self.tool;
50 let is_optional_tool = self.is_optional_tool;
54 builder.ensure(compile::Std { compiler, target: compiler.host });
55 builder.ensure(compile::Rustc { compiler, target });
57 Mode::ToolStd => builder.ensure(compile::Std { compiler, target }),
58 Mode::ToolBootstrap => {} // uses downloaded stage0 compiler libs
59 _ => panic!("unexpected Mode for tool build"),
62 let cargo = prepare_tool_cargo(
73 builder.info(&format!("Building stage{} tool {} ({})", compiler.stage, tool, target));
74 let mut duplicates = Vec::new();
75 let is_expected = compile::stream_cargo(builder, cargo, vec![], &mut |msg| {
76 // Only care about big things like the RLS/Cargo for now
78 "rls" | "cargo" | "clippy-driver" | "miri" | "rustfmt" => {}
82 let (id, features, filenames) = match msg {
83 compile::CargoMessage::CompilerArtifact {
88 } => (package_id, features, filenames),
91 let features = features.iter().map(|s| s.to_string()).collect::<Vec<_>>();
93 for path in filenames {
94 let val = (tool, PathBuf::from(&*path), features.clone());
95 // we're only interested in deduplicating rlibs for now
96 if val.1.extension().and_then(|s| s.to_str()) != Some("rlib") {
100 // Don't worry about compiles that turn out to be host
101 // dependencies or build scripts. To skip these we look for
102 // anything that goes in `.../release/deps` but *doesn't* go in
103 // `$target/release/deps`. This ensure that outputs in
104 // `$target/release` are still considered candidates for
106 if let Some(parent) = val.1.parent() {
107 if parent.ends_with("release/deps") {
108 let maybe_target = parent
110 .and_then(|p| p.parent())
111 .and_then(|p| p.file_name())
112 .and_then(|p| p.to_str())
114 if maybe_target != &*target.triple {
120 // Record that we've built an artifact for `id`, and if one was
121 // already listed then we need to see if we reused the same
122 // artifact or produced a duplicate.
123 let mut artifacts = builder.tool_artifacts.borrow_mut();
124 let prev_artifacts = artifacts.entry(target).or_default();
125 let prev = match prev_artifacts.get(&*id) {
128 prev_artifacts.insert(id.to_string(), val);
133 return; // same path, same artifact
136 // If the paths are different and one of them *isn't* inside of
137 // `release/deps`, then it means it's probably in
138 // `$target/release`, or it's some final artifact like
139 // `libcargo.rlib`. In these situations Cargo probably just
140 // copied it up from `$target/release/deps/libcargo-xxxx.rlib`,
141 // so if the features are equal we can just skip it.
142 let prev_no_hash = prev.1.parent().unwrap().ends_with("release/deps");
143 let val_no_hash = val.1.parent().unwrap().ends_with("release/deps");
144 if prev.2 == val.2 || !prev_no_hash || !val_no_hash {
148 // ... and otherwise this looks like we duplicated some sort of
149 // compilation, so record it to generate an error later.
150 duplicates.push((id.to_string(), val, prev.clone()));
154 if is_expected && !duplicates.is_empty() {
156 "duplicate artifacts found when compiling a tool, this \
157 typically means that something was recompiled because \
158 a transitive dependency has different features activated \
159 than in a previous build:\n"
162 "the following dependencies are duplicated although they \
163 have the same features enabled:"
165 let (same, different): (Vec<_>, Vec<_>) =
166 duplicates.into_iter().partition(|(_, cur, prev)| cur.2 == prev.2);
167 for (id, cur, prev) in same {
170 println!(" `{}` ({:?})\n `{}` ({:?})", cur.0, cur.1, prev.0, prev.1);
172 println!("the following dependencies have different features:");
173 for (id, cur, prev) in different {
175 let cur_features: HashSet<_> = cur.2.into_iter().collect();
176 let prev_features: HashSet<_> = prev.2.into_iter().collect();
178 " `{}` additionally enabled features {:?} at {:?}",
180 &cur_features - &prev_features,
184 " `{}` additionally enabled features {:?} at {:?}",
186 &prev_features - &cur_features,
192 "to fix this you will probably want to edit the local \
193 src/tools/rustc-workspace-hack/Cargo.toml crate, as \
194 that will update the dependency graph to ensure that \
195 these crates all share the same feature set"
197 panic!("tools should not compile multiple copies of the same crate");
200 builder.save_toolstate(
202 if is_expected { ToolState::TestFail } else { ToolState::BuildFail },
206 if !is_optional_tool {
212 // HACK(#82501): on Windows, the tools directory gets added to PATH when running tests, and
213 // compiletest confuses HTML tidy with the in-tree tidy. Name the in-tree tidy something
214 // different so the problem doesn't come up.
218 let cargo_out = builder.cargo_out(compiler, self.mode, target).join(exe(tool, target));
219 let bin = builder.tools_dir(compiler).join(exe(tool, target));
220 builder.copy(&cargo_out, &bin);
226 pub fn prepare_tool_cargo(
227 builder: &Builder<'_>,
230 target: TargetSelection,
231 command: &'static str,
233 source_type: SourceType,
234 extra_features: &[String],
236 let mut cargo = builder.cargo(compiler, mode, source_type, target, command);
237 let dir = builder.src.join(path);
238 cargo.arg("--manifest-path").arg(dir.join("Cargo.toml"));
240 let mut features = extra_features.to_vec();
241 if builder.build.config.cargo_native_static {
242 if path.ends_with("cargo")
243 || path.ends_with("rls")
244 || path.ends_with("clippy")
245 || path.ends_with("miri")
246 || path.ends_with("rustfmt")
248 cargo.env("LIBZ_SYS_STATIC", "1");
249 features.push("rustc-workspace-hack/all-static".to_string());
253 // if tools are using lzma we want to force the build script to build its
255 cargo.env("LZMA_API_STATIC", "1");
257 // CFG_RELEASE is needed by rustfmt (and possibly other tools) which
258 // import rustc-ap-rustc_attr which requires this to be set for the
259 // `#[cfg(version(...))]` attribute.
260 cargo.env("CFG_RELEASE", builder.rust_release());
261 cargo.env("CFG_RELEASE_CHANNEL", &builder.config.channel);
262 cargo.env("CFG_VERSION", builder.rust_version());
263 cargo.env("CFG_RELEASE_NUM", &builder.version);
264 cargo.env("DOC_RUST_LANG_ORG_CHANNEL", builder.doc_rust_lang_org_channel());
266 let info = GitInfo::new(builder.config.ignore_git, &dir);
267 if let Some(sha) = info.sha() {
268 cargo.env("CFG_COMMIT_HASH", sha);
270 if let Some(sha_short) = info.sha_short() {
271 cargo.env("CFG_SHORT_COMMIT_HASH", sha_short);
273 if let Some(date) = info.commit_date() {
274 cargo.env("CFG_COMMIT_DATE", date);
276 if !features.is_empty() {
277 cargo.arg("--features").arg(&features.join(", "));
282 macro_rules! bootstrap_tool {
284 $name:ident, $path:expr, $tool_name:expr
285 $(,is_external_tool = $external:expr)*
286 $(,is_unstable_tool = $unstable:expr)*
289 #[derive(Copy, PartialEq, Eq, Clone)]
296 impl<'a> Builder<'a> {
297 pub fn tool_exe(&self, tool: Tool) -> PathBuf {
301 compiler: self.compiler(0, self.config.build),
302 target: self.config.build,
310 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
312 pub compiler: Compiler,
313 pub target: TargetSelection,
316 impl Step for $name {
317 type Output = PathBuf;
319 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
323 fn make_run(run: RunConfig<'_>) {
324 run.builder.ensure($name {
326 compiler: run.builder.compiler(0, run.builder.config.build),
331 fn run(self, builder: &Builder<'_>) -> PathBuf {
332 builder.ensure(ToolBuild {
333 compiler: self.compiler,
336 mode: if false $(|| $unstable)* {
337 // use in-tree libraries for unstable features
343 is_optional_tool: false,
344 source_type: if false $(|| $external)* {
345 SourceType::Submodule
349 extra_features: vec![],
350 }).expect("expected to build -- essential tool")
358 Rustbook, "src/tools/rustbook", "rustbook";
359 UnstableBookGen, "src/tools/unstable-book-gen", "unstable-book-gen";
360 Tidy, "src/tools/tidy", "tidy";
361 Linkchecker, "src/tools/linkchecker", "linkchecker";
362 CargoTest, "src/tools/cargotest", "cargotest";
363 Compiletest, "src/tools/compiletest", "compiletest", is_unstable_tool = true;
364 BuildManifest, "src/tools/build-manifest", "build-manifest";
365 RemoteTestClient, "src/tools/remote-test-client", "remote-test-client";
366 RustInstaller, "src/tools/rust-installer", "fabricate", is_external_tool = true;
367 RustdocTheme, "src/tools/rustdoc-themes", "rustdoc-themes";
368 ExpandYamlAnchors, "src/tools/expand-yaml-anchors", "expand-yaml-anchors";
369 LintDocs, "src/tools/lint-docs", "lint-docs";
370 JsonDocCk, "src/tools/jsondocck", "jsondocck";
371 HtmlChecker, "src/tools/html-checker", "html-checker";
372 BumpStage0, "src/tools/bump-stage0", "bump-stage0";
375 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
376 pub struct ErrorIndex {
377 pub compiler: Compiler,
381 pub fn command(builder: &Builder<'_>) -> Command {
382 // This uses stage-1 to match the behavior of building rustdoc.
383 // Error-index-generator links with the rustdoc library, so we want to
384 // use the same librustdoc to avoid building rustdoc twice (and to
385 // avoid building the compiler an extra time). This uses
386 // saturating_sub to deal with building with stage 0. (Using stage 0
387 // isn't recommended, since it will fail if any new error index tests
388 // use new syntax, but it should work otherwise.)
389 let compiler = builder.compiler(builder.top_stage.saturating_sub(1), builder.config.build);
390 let mut cmd = Command::new(builder.ensure(ErrorIndex { compiler }));
393 PathBuf::from(&builder.sysroot_libdir(compiler, compiler.host)),
394 builder.rustc_libdir(compiler),
402 impl Step for ErrorIndex {
403 type Output = PathBuf;
405 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
406 run.path("src/tools/error_index_generator")
409 fn make_run(run: RunConfig<'_>) {
410 // Compile the error-index in the same stage as rustdoc to avoid
411 // recompiling rustdoc twice if we can.
413 // NOTE: This `make_run` isn't used in normal situations, only if you
414 // manually build the tool with `x.py build
415 // src/tools/error-index-generator` which almost nobody does.
416 // Normally, `x.py test` or `x.py doc` will use the
417 // `ErrorIndex::command` function instead.
419 run.builder.compiler(run.builder.top_stage.saturating_sub(1), run.builder.config.build);
420 run.builder.ensure(ErrorIndex { compiler });
423 fn run(self, builder: &Builder<'_>) -> PathBuf {
426 compiler: self.compiler,
427 target: self.compiler.host,
428 tool: "error_index_generator",
429 mode: Mode::ToolRustc,
430 path: "src/tools/error_index_generator",
431 is_optional_tool: false,
432 source_type: SourceType::InTree,
433 extra_features: Vec::new(),
435 .expect("expected to build -- essential tool")
439 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
440 pub struct RemoteTestServer {
441 pub compiler: Compiler,
442 pub target: TargetSelection,
445 impl Step for RemoteTestServer {
446 type Output = PathBuf;
448 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
449 run.path("src/tools/remote-test-server")
452 fn make_run(run: RunConfig<'_>) {
453 run.builder.ensure(RemoteTestServer {
454 compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
459 fn run(self, builder: &Builder<'_>) -> PathBuf {
462 compiler: self.compiler,
464 tool: "remote-test-server",
466 path: "src/tools/remote-test-server",
467 is_optional_tool: false,
468 source_type: SourceType::InTree,
469 extra_features: Vec::new(),
471 .expect("expected to build -- essential tool")
475 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
477 /// This should only ever be 0 or 2.
478 /// We sometimes want to reference the "bootstrap" rustdoc, which is why this option is here.
479 pub compiler: Compiler,
482 impl Step for Rustdoc {
483 type Output = PathBuf;
484 const DEFAULT: bool = true;
485 const ONLY_HOSTS: bool = true;
487 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
488 run.path("src/tools/rustdoc").path("src/librustdoc")
491 fn make_run(run: RunConfig<'_>) {
492 run.builder.ensure(Rustdoc {
493 // Note: this is somewhat unique in that we actually want a *target*
494 // compiler here, because rustdoc *is* a compiler. We won't be using
495 // this as the compiler to build with, but rather this is "what
496 // compiler are we producing"?
497 compiler: run.builder.compiler(run.builder.top_stage, run.target),
501 fn run(self, builder: &Builder<'_>) -> PathBuf {
502 let target_compiler = self.compiler;
503 if target_compiler.stage == 0 {
504 if !target_compiler.is_snapshot(builder) {
505 panic!("rustdoc in stage 0 must be snapshot rustdoc");
507 return builder.initial_rustc.with_file_name(exe("rustdoc", target_compiler.host));
509 let target = target_compiler.host;
510 // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
511 // we'd have stageN/bin/rustc and stageN/bin/rustdoc be effectively different stage
512 // compilers, which isn't what we want. Rustdoc should be linked in the same way as the
513 // rustc compiler it's paired with, so it must be built with the previous stage compiler.
514 let build_compiler = builder.compiler(target_compiler.stage - 1, builder.config.build);
516 // When using `download-rustc` and a stage0 build_compiler, copying rustc doesn't actually
517 // build stage0 libstd (because the libstd in sysroot has the wrong ABI). Explicitly build
519 builder.ensure(compile::Std { compiler: build_compiler, target: target_compiler.host });
520 builder.ensure(compile::Rustc { compiler: build_compiler, target: target_compiler.host });
521 // NOTE: this implies that `download-rustc` is pretty useless when compiling with the stage0
522 // compiler, since you do just as much work.
523 if !builder.config.dry_run && builder.config.download_rustc && build_compiler.stage == 0 {
525 "warning: `download-rustc` does nothing when building stage1 tools; consider using `--stage 2` instead"
529 // The presence of `target_compiler` ensures that the necessary libraries (codegen backends,
530 // compiler libraries, ...) are built. Rustdoc does not require the presence of any
531 // libraries within sysroot_libdir (i.e., rustlib), though doctests may want it (since
532 // they'll be linked to those libraries). As such, don't explicitly `ensure` any additional
533 // libraries here. The intuition here is that If we've built a compiler, we should be able
536 let mut features = Vec::new();
537 if builder.config.jemalloc {
538 features.push("jemalloc".to_string());
541 let cargo = prepare_tool_cargo(
552 builder.info(&format!(
553 "Building rustdoc for stage{} ({})",
554 target_compiler.stage, target_compiler.host
556 builder.run(&mut cargo.into());
558 // Cargo adds a number of paths to the dylib search path on windows, which results in
559 // the wrong rustdoc being executed. To avoid the conflicting rustdocs, we name the "tool"
560 // rustdoc a different name.
561 let tool_rustdoc = builder
562 .cargo_out(build_compiler, Mode::ToolRustc, target)
563 .join(exe("rustdoc_tool_binary", target_compiler.host));
565 // don't create a stage0-sysroot/bin directory.
566 if target_compiler.stage > 0 {
567 let sysroot = builder.sysroot(target_compiler);
568 let bindir = sysroot.join("bin");
569 t!(fs::create_dir_all(&bindir));
570 let bin_rustdoc = bindir.join(exe("rustdoc", target_compiler.host));
571 let _ = fs::remove_file(&bin_rustdoc);
572 builder.copy(&tool_rustdoc, &bin_rustdoc);
580 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
582 pub compiler: Compiler,
583 pub target: TargetSelection,
586 impl Step for Cargo {
587 type Output = PathBuf;
588 const DEFAULT: bool = true;
589 const ONLY_HOSTS: bool = true;
591 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
592 let builder = run.builder;
593 run.path("src/tools/cargo").default_condition(
594 builder.config.extended
595 && builder.config.tools.as_ref().map_or(
597 // If `tools` is set, search list for this tool.
598 |tools| tools.iter().any(|tool| tool == "cargo"),
603 fn make_run(run: RunConfig<'_>) {
604 run.builder.ensure(Cargo {
605 compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
610 fn run(self, builder: &Builder<'_>) -> PathBuf {
611 let cargo_bin_path = builder
613 compiler: self.compiler,
616 mode: Mode::ToolRustc,
617 path: "src/tools/cargo",
618 is_optional_tool: false,
619 source_type: SourceType::Submodule,
620 extra_features: Vec::new(),
622 .expect("expected to build -- essential tool");
624 let build_cred = |name, path| {
625 // These credential helpers are currently experimental.
626 // Any build failures will be ignored.
627 let _ = builder.ensure(ToolBuild {
628 compiler: self.compiler,
631 mode: Mode::ToolRustc,
633 is_optional_tool: true,
634 source_type: SourceType::Submodule,
635 extra_features: Vec::new(),
639 if self.target.contains("windows") {
641 "cargo-credential-wincred",
642 "src/tools/cargo/crates/credential/cargo-credential-wincred",
645 if self.target.contains("apple-darwin") {
647 "cargo-credential-macos-keychain",
648 "src/tools/cargo/crates/credential/cargo-credential-macos-keychain",
652 "cargo-credential-1password",
653 "src/tools/cargo/crates/credential/cargo-credential-1password",
659 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
660 pub struct LldWrapper {
661 pub compiler: Compiler,
662 pub target: TargetSelection,
663 pub flavor_feature: &'static str,
666 impl Step for LldWrapper {
667 type Output = PathBuf;
669 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
673 fn run(self, builder: &Builder<'_>) -> PathBuf {
674 let src_exe = builder
676 compiler: self.compiler,
680 path: "src/tools/lld-wrapper",
681 is_optional_tool: false,
682 source_type: SourceType::InTree,
683 extra_features: vec![self.flavor_feature.to_owned()],
685 .expect("expected to build -- essential tool");
691 macro_rules! tool_extended {
692 (($sel:ident, $builder:ident),
697 stable = $stable:expr,
698 $(in_tree = $in_tree:expr,)?
699 $(submodule = $submodule:literal,)?
700 $extra_deps:block;)+) => {
702 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
704 pub compiler: Compiler,
705 pub target: TargetSelection,
706 pub extra_features: Vec<String>,
709 impl Step for $name {
710 type Output = Option<PathBuf>;
711 const DEFAULT: bool = true; // Overwritten below
712 const ONLY_HOSTS: bool = true;
714 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
715 let builder = run.builder;
716 run.path($path).default_condition(
717 builder.config.extended
718 && builder.config.tools.as_ref().map_or(
719 // By default, on nightly/dev enable all tools, else only
720 // build stable tools.
721 $stable || builder.build.unstable_features(),
722 // If `tools` is set, search list for this tool.
724 tools.iter().any(|tool| match tool.as_ref() {
725 "clippy" => $tool_name == "clippy-driver",
726 x => $tool_name == x,
732 fn make_run(run: RunConfig<'_>) {
733 run.builder.ensure($name {
734 compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
736 extra_features: Vec::new(),
741 fn run(mut $sel, $builder: &Builder<'_>) -> Option<PathBuf> {
743 $( $builder.update_submodule(&Path::new("src").join("tools").join($submodule)); )?
744 $builder.ensure(ToolBuild {
745 compiler: $sel.compiler,
748 mode: Mode::ToolRustc,
750 extra_features: $sel.extra_features,
751 is_optional_tool: true,
752 source_type: if false $(|| $in_tree)* {
755 SourceType::Submodule
764 // Note: tools need to be also added to `Builder::get_step_descriptions` in `builder.rs`
765 // to make `./x.py build <tool>` work.
766 // Note: Most submodule updates for tools are handled by bootstrap.py, since they're needed just to
767 // invoke Cargo to build bootstrap. See the comment there for more details.
768 tool_extended!((self, builder),
769 Cargofmt, rustfmt, "src/tools/rustfmt", "cargo-fmt", stable=true, in_tree=true, {};
770 CargoClippy, clippy, "src/tools/clippy", "cargo-clippy", stable=true, in_tree=true, {};
771 Clippy, clippy, "src/tools/clippy", "clippy-driver", stable=true, in_tree=true, {};
772 Miri, miri, "src/tools/miri", "miri", stable=false, {};
773 CargoMiri, miri, "src/tools/miri/cargo-miri", "cargo-miri", stable=false, {};
774 Rls, rls, "src/tools/rls", "rls", stable=true, {
775 builder.ensure(Clippy {
776 compiler: self.compiler,
778 extra_features: Vec::new(),
780 self.extra_features.push("clippy".to_owned());
782 RustDemangler, rust_demangler, "src/tools/rust-demangler", "rust-demangler", stable=false, in_tree=true, {};
783 Rustfmt, rustfmt, "src/tools/rustfmt", "rustfmt", stable=true, in_tree=true, {};
784 RustAnalyzer, rust_analyzer, "src/tools/rust-analyzer/crates/rust-analyzer", "rust-analyzer", stable=false, submodule="rust-analyzer", {};
787 impl<'a> Builder<'a> {
788 /// Gets a `Command` which is ready to run `tool` in `stage` built for
790 pub fn tool_cmd(&self, tool: Tool) -> Command {
791 let mut cmd = Command::new(self.tool_exe(tool));
792 let compiler = self.compiler(0, self.config.build);
793 let host = &compiler.host;
794 // Prepares the `cmd` provided to be able to run the `compiler` provided.
796 // Notably this munges the dynamic library lookup path to point to the
797 // right location to run `compiler`.
798 let mut lib_paths: Vec<PathBuf> = vec![
799 self.build.rustc_snapshot_libdir(),
800 self.cargo_out(compiler, Mode::ToolBootstrap, *host).join("deps"),
803 // On MSVC a tool may invoke a C compiler (e.g., compiletest in run-make
804 // mode) and that C compiler may need some extra PATH modification. Do
806 if compiler.host.contains("msvc") {
807 let curpaths = env::var_os("PATH").unwrap_or_default();
808 let curpaths = env::split_paths(&curpaths).collect::<Vec<_>>();
809 for &(ref k, ref v) in self.cc[&compiler.host].env() {
813 for path in env::split_paths(v) {
814 if !curpaths.contains(&path) {
815 lib_paths.push(path);
821 add_dylib_path(lib_paths, &mut cmd);
823 // Provide a RUSTC for this command to use.
824 cmd.env("RUSTC", &self.initial_rustc);