Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1679 insertions, 0 deletions

diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
new file mode 100644
index 000000000..d265277b4
--- /dev/null
+++ b/src/bootstrap/lib.rs
@@ -0,0 +1,1679 @@
+//! Implementation of rustbuild, the Rust build system.
+//!
+//! This module, and its descendants, are the implementation of the Rust build
+//! system. Most of this build system is backed by Cargo but the outer layer
+//! here serves as the ability to orchestrate calling Cargo, sequencing Cargo
+//! builds, building artifacts like LLVM, etc. The goals of rustbuild are:
+//!
+//! * To be an easily understandable, easily extensible, and maintainable build
+//!   system.
+//! * Leverage standard tools in the Rust ecosystem to build the compiler, aka
+//!   crates.io and Cargo.
+//! * A standard interface to build across all platforms, including MSVC
+//!
+//! ## Architecture
+//!
+//! The build system defers most of the complicated logic managing invocations
+//! of rustc and rustdoc to Cargo itself. However, moving through various stages
+//! and copying artifacts is still necessary for it to do. Each time rustbuild
+//! is invoked, it will iterate through the list of predefined steps and execute
+//! each serially in turn if it matches the paths passed or is a default rule.
+//! For each step rustbuild relies on the step internally being incremental and
+//! parallel. Note, though, that the `-j` parameter to rustbuild gets forwarded
+//! to appropriate test harnesses and such.
+//!
+//! Most of the "meaty" steps that matter are backed by Cargo, which does indeed
+//! have its own parallelism and incremental management. Later steps, like
+//! tests, aren't incremental and simply run the entire suite currently.
+//! However, compiletest itself tries to avoid running tests when the artifacts
+//! that are involved (mainly the compiler) haven't changed.
+//!
+//! When you execute `x.py build`, the steps executed are:
+//!
+//! * First, the python script is run. This will automatically download the
+//!   stage0 rustc and cargo according to `src/stage0.json`, or use the cached
+//!   versions if they're available. These are then used to compile rustbuild
+//!   itself (using Cargo). Finally, control is then transferred to rustbuild.
+//!
+//! * Rustbuild takes over, performs sanity checks, probes the environment,
+//!   reads configuration, and starts executing steps as it reads the command
+//!   line arguments (paths) or going through the default rules.
+//!
+//!   The build output will be something like the following:
+//!
+//!   Building stage0 std artifacts
+//!   Copying stage0 std
+//!   Building stage0 test artifacts
+//!   Copying stage0 test
+//!   Building stage0 compiler artifacts
+//!   Copying stage0 rustc
+//!   Assembling stage1 compiler
+//!   Building stage1 std artifacts
+//!   Copying stage1 std
+//!   Building stage1 test artifacts
+//!   Copying stage1 test
+//!   Building stage1 compiler artifacts
+//!   Copying stage1 rustc
+//!   Assembling stage2 compiler
+//!   Uplifting stage1 std
+//!   Uplifting stage1 test
+//!   Uplifting stage1 rustc
+//!
+//! Let's disect that a little:
+//!
+//! ## Building stage0 {std,test,compiler} artifacts
+//!
+//! These steps use the provided (downloaded, usually) compiler to compile the
+//! local Rust source into libraries we can use.
+//!
+//! ## Copying stage0 {std,test,rustc}
+//!
+//! This copies the build output from Cargo into
+//! `build/$HOST/stage0-sysroot/lib/rustlib/$ARCH/lib`. FIXME: this step's
+//! documentation should be expanded -- the information already here may be
+//! incorrect.
+//!
+//! ## Assembling stage1 compiler
+//!
+//! This copies the libraries we built in "building stage0 ... artifacts" into
+//! the stage1 compiler's lib directory. These are the host libraries that the
+//! compiler itself uses to run. These aren't actually used by artifacts the new
+//! compiler generates. This step also copies the rustc and rustdoc binaries we
+//! generated into build/$HOST/stage/bin.
+//!
+//! The stage1/bin/rustc is a fully functional compiler, but it doesn't yet have
+//! any libraries to link built binaries or libraries to. The next 3 steps will
+//! provide those libraries for it; they are mostly equivalent to constructing
+//! the stage1/bin compiler so we don't go through them individually.
+//!
+//! ## Uplifting stage1 {std,test,rustc}
+//!
+//! This step copies the libraries from the stage1 compiler sysroot into the
+//! stage2 compiler. This is done to avoid rebuilding the compiler; libraries
+//! we'd build in this step should be identical (in function, if not necessarily
+//! identical on disk) so there's no need to recompile the compiler again. Note
+//! that if you want to, you can enable the full-bootstrap option to change this
+//! behavior.
+//!
+//! Each step is driven by a separate Cargo project and rustbuild orchestrates
+//! copying files between steps and otherwise preparing for Cargo to run.
+//!
+//! ## Further information
+//!
+//! More documentation can be found in each respective module below, and you can
+//! also check out the `src/bootstrap/README.md` file for more information.
+
+use std::cell::{Cell, RefCell};
+use std::collections::{HashMap, HashSet};
+use std::env;
+use std::fs::{self, File};
+use std::io;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+use std::str;
+
+use filetime::FileTime;
+use once_cell::sync::OnceCell;
+
+use crate::builder::Kind;
+use crate::config::{LlvmLibunwind, TargetSelection};
+use crate::util::{
+    check_run, exe, libdir, mtime, output, run, run_suppressed, try_run, try_run_suppressed, CiEnv,
+};
+
+mod builder;
+mod cache;
+mod cc_detect;
+mod channel;
+mod check;
+mod clean;
+mod compile;
+mod config;
+mod dist;
+mod doc;
+mod flags;
+mod format;
+mod install;
+mod metadata;
+mod native;
+mod run;
+mod sanity;
+mod setup;
+mod tarball;
+mod test;
+mod tool;
+mod toolstate;
+pub mod util;
+
+#[cfg(feature = "build-metrics")]
+mod metrics;
+
+#[cfg(windows)]
+mod job;
+
+#[cfg(all(unix, not(target_os = "haiku")))]
+mod job {
+    pub unsafe fn setup(build: &mut crate::Build) {
+        if build.config.low_priority {
+            libc::setpriority(libc::PRIO_PGRP as _, 0, 10);
+        }
+    }
+}
+
+#[cfg(any(target_os = "haiku", target_os = "hermit", not(any(unix, windows))))]
+mod job {
+    pub unsafe fn setup(_build: &mut crate::Build) {}
+}
+
+pub use crate::builder::PathSet;
+use crate::cache::{Interned, INTERNER};
+pub use crate::config::Config;
+pub use crate::flags::Subcommand;
+
+const LLVM_TOOLS: &[&str] = &[
+    "llvm-cov",      // used to generate coverage report
+    "llvm-nm",       // used to inspect binaries; it shows symbol names, their sizes and visibility
+    "llvm-objcopy",  // used to transform ELFs into binary format which flashing tools consume
+    "llvm-objdump",  // used to disassemble programs
+    "llvm-profdata", // used to inspect and merge files generated by profiles
+    "llvm-readobj",  // used to get information from ELFs/objects that the other tools don't provide
+    "llvm-size",     // used to prints the size of the linker sections of a program
+    "llvm-strip",    // used to discard symbols from binary files to reduce their size
+    "llvm-ar",       // used for creating and modifying archive files
+    "llvm-as",       // used to convert LLVM assembly to LLVM bitcode
+    "llvm-dis",      // used to disassemble LLVM bitcode
+    "llc",           // used to compile LLVM bytecode
+    "opt",           // used to optimize LLVM bytecode
+];
+
+pub const VERSION: usize = 2;
+
+/// Extra --check-cfg to add when building
+/// (Mode restriction, config name, config values (if any))
+const EXTRA_CHECK_CFGS: &[(Option<Mode>, &'static str, Option<&[&'static str]>)] = &[
+    (None, "bootstrap", None),
+    (Some(Mode::Rustc), "parallel_compiler", None),
+    (Some(Mode::ToolRustc), "parallel_compiler", None),
+    (Some(Mode::Std), "stdarch_intel_sde", None),
+    (Some(Mode::Std), "no_fp_fmt_parse", None),
+    (Some(Mode::Std), "no_global_oom_handling", None),
+    (Some(Mode::Std), "freebsd12", None),
+    (Some(Mode::Std), "backtrace_in_libstd", None),
+    /* Extra values not defined in the built-in targets yet, but used in std */
+    (Some(Mode::Std), "target_env", Some(&["libnx"])),
+    (Some(Mode::Std), "target_os", Some(&["watchos"])),
+    (
+        Some(Mode::Std),
+        "target_arch",
+        Some(&["asmjs", "spirv", "nvptx", "nvptx64", "le32", "xtensa"]),
+    ),
+    /* Extra names used by dependencies */
+    // FIXME: Used by rustfmt is their test but is invalid (neither cargo nor bootstrap ever set
+    // this config) should probably by removed or use a allow attribute.
+    (Some(Mode::ToolRustc), "release", None),
+    // FIXME: Used by stdarch in their test, should use a allow attribute instead.
+    (Some(Mode::Std), "dont_compile_me", None),
+    // FIXME: Used by serde_json, but we should not be triggering on external dependencies.
+    (Some(Mode::Rustc), "no_btreemap_remove_entry", None),
+    (Some(Mode::ToolRustc), "no_btreemap_remove_entry", None),
+    // FIXME: Used by crossbeam-utils, but we should not be triggering on external dependencies.
+    (Some(Mode::Rustc), "crossbeam_loom", None),
+    (Some(Mode::ToolRustc), "crossbeam_loom", None),
+    // FIXME: Used by proc-macro2, but we should not be triggering on external dependencies.
+    (Some(Mode::Rustc), "span_locations", None),
+    (Some(Mode::ToolRustc), "span_locations", None),
+];
+
+/// A structure representing a Rust compiler.
+///
+/// Each compiler has a `stage` that it is associated with and a `host` that
+/// corresponds to the platform the compiler runs on. This structure is used as
+/// a parameter to many methods below.
+#[derive(Eq, PartialOrd, Ord, PartialEq, Clone, Copy, Hash, Debug)]
+pub struct Compiler {
+    stage: u32,
+    host: TargetSelection,
+}
+
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+pub enum DocTests {
+    /// Run normal tests and doc tests (default).
+    Yes,
+    /// Do not run any doc tests.
+    No,
+    /// Only run doc tests.
+    Only,
+}
+
+pub enum GitRepo {
+    Rustc,
+    Llvm,
+}
+
+/// Global configuration for the build system.
+///
+/// This structure transitively contains all configuration for the build system.
+/// All filesystem-encoded configuration is in `config`, all flags are in
+/// `flags`, and then parsed or probed information is listed in the keys below.
+///
+/// This structure is a parameter of almost all methods in the build system,
+/// although most functions are implemented as free functions rather than
+/// methods specifically on this structure itself (to make it easier to
+/// organize).
+pub struct Build {
+    /// User-specified configuration from `config.toml`.
+    config: Config,
+
+    // Version information
+    version: String,
+
+    // Properties derived from the above configuration
+    src: PathBuf,
+    out: PathBuf,
+    bootstrap_out: PathBuf,
+    rust_info: channel::GitInfo,
+    cargo_info: channel::GitInfo,
+    rls_info: channel::GitInfo,
+    rust_analyzer_info: channel::GitInfo,
+    clippy_info: channel::GitInfo,
+    miri_info: channel::GitInfo,
+    rustfmt_info: channel::GitInfo,
+    in_tree_llvm_info: channel::GitInfo,
+    local_rebuild: bool,
+    fail_fast: bool,
+    doc_tests: DocTests,
+    verbosity: usize,
+
+    // Targets for which to build
+    build: TargetSelection,
+    hosts: Vec<TargetSelection>,
+    targets: Vec<TargetSelection>,
+
+    initial_rustc: PathBuf,
+    initial_cargo: PathBuf,
+    initial_lld: PathBuf,
+    initial_libdir: PathBuf,
+
+    // Runtime state filled in later on
+    // C/C++ compilers and archiver for all targets
+    cc: HashMap<TargetSelection, cc::Tool>,
+    cxx: HashMap<TargetSelection, cc::Tool>,
+    ar: HashMap<TargetSelection, PathBuf>,
+    ranlib: HashMap<TargetSelection, PathBuf>,
+    // Miscellaneous
+    // allow bidirectional lookups: both name -> path and path -> name
+    crates: HashMap<Interned<String>, Crate>,
+    crate_paths: HashMap<PathBuf, Interned<String>>,
+    is_sudo: bool,
+    ci_env: CiEnv,
+    delayed_failures: RefCell<Vec<String>>,
+    prerelease_version: Cell<Option<u32>>,
+    tool_artifacts:
+        RefCell<HashMap<TargetSelection, HashMap<String, (&'static str, PathBuf, Vec<String>)>>>,
+
+    #[cfg(feature = "build-metrics")]
+    metrics: metrics::BuildMetrics,
+}
+
+#[derive(Debug)]
+struct Crate {
+    name: Interned<String>,
+    deps: HashSet<Interned<String>>,
+    path: PathBuf,
+}
+
+impl Crate {
+    fn local_path(&self, build: &Build) -> PathBuf {
+        self.path.strip_prefix(&build.config.src).unwrap().into()
+    }
+}
+
+/// When building Rust various objects are handled differently.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub enum DependencyType {
+    /// Libraries originating from proc-macros.
+    Host,
+    /// Typical Rust libraries.
+    Target,
+    /// Non Rust libraries and objects shipped to ease usage of certain targets.
+    TargetSelfContained,
+}
+
+/// The various "modes" of invoking Cargo.
+///
+/// These entries currently correspond to the various output directories of the
+/// build system, with each mod generating output in a different directory.
+#[derive(Debug, Hash, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub enum Mode {
+    /// Build the standard library, placing output in the "stageN-std" directory.
+    Std,
+
+    /// Build librustc, and compiler libraries, placing output in the "stageN-rustc" directory.
+    Rustc,
+
+    /// Build a codegen backend for rustc, placing the output in the "stageN-codegen" directory.
+    Codegen,
+
+    /// Build a tool, placing output in the "stage0-bootstrap-tools"
+    /// directory. This is for miscellaneous sets of tools that are built
+    /// using the bootstrap stage0 compiler in its entirety (target libraries
+    /// and all). Typically these tools compile with stable Rust.
+    ToolBootstrap,
+
+    /// Build a tool which uses the locally built std, placing output in the
+    /// "stageN-tools" directory. Its usage is quite rare, mainly used by
+    /// compiletest which needs libtest.
+    ToolStd,
+
+    /// Build a tool which uses the locally built rustc and the target std,
+    /// placing the output in the "stageN-tools" directory. This is used for
+    /// anything that needs a fully functional rustc, such as rustdoc, clippy,
+    /// cargo, rls, rustfmt, miri, etc.
+    ToolRustc,
+}
+
+impl Mode {
+    pub fn is_tool(&self) -> bool {
+        matches!(self, Mode::ToolBootstrap | Mode::ToolRustc | Mode::ToolStd)
+    }
+
+    pub fn must_support_dlopen(&self) -> bool {
+        matches!(self, Mode::Std | Mode::Codegen)
+    }
+}
+
+pub enum CLang {
+    C,
+    Cxx,
+}
+
+impl Build {
+    /// Creates a new set of build configuration from the `flags` on the command
+    /// line and the filesystem `config`.
+    ///
+    /// By default all build output will be placed in the current directory.
+    pub fn new(config: Config) -> Build {
+        let src = config.src.clone();
+        let out = config.out.clone();
+
+        #[cfg(unix)]
+        // keep this consistent with the equivalent check in x.py:
+        // https://github.com/rust-lang/rust/blob/a8a33cf27166d3eabaffc58ed3799e054af3b0c6/src/bootstrap/bootstrap.py#L796-L797
+        let is_sudo = match env::var_os("SUDO_USER") {
+            Some(_sudo_user) => {
+                let uid = unsafe { libc::getuid() };
+                uid == 0
+            }
+            None => false,
+        };
+        #[cfg(not(unix))]
+        let is_sudo = false;
+
+        let ignore_git = config.ignore_git;
+        let rust_info = channel::GitInfo::new(ignore_git, &src);
+        let cargo_info = channel::GitInfo::new(ignore_git, &src.join("src/tools/cargo"));
+        let rls_info = channel::GitInfo::new(ignore_git, &src.join("src/tools/rls"));
+        let rust_analyzer_info =
+            channel::GitInfo::new(ignore_git, &src.join("src/tools/rust-analyzer"));
+        let clippy_info = channel::GitInfo::new(ignore_git, &src.join("src/tools/clippy"));
+        let miri_info = channel::GitInfo::new(ignore_git, &src.join("src/tools/miri"));
+        let rustfmt_info = channel::GitInfo::new(ignore_git, &src.join("src/tools/rustfmt"));
+
+        // we always try to use git for LLVM builds
+        let in_tree_llvm_info = channel::GitInfo::new(false, &src.join("src/llvm-project"));
+
+        let initial_target_libdir_str = if config.dry_run {
+            "/dummy/lib/path/to/lib/".to_string()
+        } else {
+            output(
+                Command::new(&config.initial_rustc)
+                    .arg("--target")
+                    .arg(config.build.rustc_target_arg())
+                    .arg("--print")
+                    .arg("target-libdir"),
+            )
+        };
+        let initial_target_dir = Path::new(&initial_target_libdir_str).parent().unwrap();
+        let initial_lld = initial_target_dir.join("bin").join("rust-lld");
+
+        let initial_sysroot = if config.dry_run {
+            "/dummy".to_string()
+        } else {
+            output(Command::new(&config.initial_rustc).arg("--print").arg("sysroot"))
+        };
+        let initial_libdir = initial_target_dir
+            .parent()
+            .unwrap()
+            .parent()
+            .unwrap()
+            .strip_prefix(initial_sysroot.trim())
+            .unwrap()
+            .to_path_buf();
+
+        let version = std::fs::read_to_string(src.join("src").join("version"))
+            .expect("failed to read src/version");
+        let version = version.trim();
+
+        let bootstrap_out = if std::env::var("BOOTSTRAP_PYTHON").is_ok() {
+            out.join("bootstrap").join("debug")
+        } else {
+            let workspace_target_dir = std::env::var("CARGO_TARGET_DIR")
+                .map(PathBuf::from)
+                .unwrap_or_else(|_| src.join("target"));
+            let bootstrap_out = workspace_target_dir.join("debug");
+            if !bootstrap_out.join("rustc").exists() && !cfg!(test) {
+                // this restriction can be lifted whenever https://github.com/rust-lang/rfcs/pull/3028 is implemented
+                panic!("run `cargo build --bins` before `cargo run`")
+            }
+            bootstrap_out
+        };
+
+        let mut build = Build {
+            initial_rustc: config.initial_rustc.clone(),
+            initial_cargo: config.initial_cargo.clone(),
+            initial_lld,
+            initial_libdir,
+            local_rebuild: config.local_rebuild,
+            fail_fast: config.cmd.fail_fast(),
+            doc_tests: config.cmd.doc_tests(),
+            verbosity: config.verbose,
+
+            build: config.build,
+            hosts: config.hosts.clone(),
+            targets: config.targets.clone(),
+
+            config,
+            version: version.to_string(),
+            src,
+            out,
+            bootstrap_out,
+
+            rust_info,
+            cargo_info,
+            rls_info,
+            rust_analyzer_info,
+            clippy_info,
+            miri_info,
+            rustfmt_info,
+            in_tree_llvm_info,
+            cc: HashMap::new(),
+            cxx: HashMap::new(),
+            ar: HashMap::new(),
+            ranlib: HashMap::new(),
+            crates: HashMap::new(),
+            crate_paths: HashMap::new(),
+            is_sudo,
+            ci_env: CiEnv::current(),
+            delayed_failures: RefCell::new(Vec::new()),
+            prerelease_version: Cell::new(None),
+            tool_artifacts: Default::default(),
+
+            #[cfg(feature = "build-metrics")]
+            metrics: metrics::BuildMetrics::init(),
+        };
+
+        build.verbose("finding compilers");
+        cc_detect::find(&mut build);
+        // When running `setup`, the profile is about to change, so any requirements we have now may
+        // be different on the next invocation. Don't check for them until the next time x.py is
+        // run. This is ok because `setup` never runs any build commands, so it won't fail if commands are missing.
+        if !matches!(build.config.cmd, Subcommand::Setup { .. }) {
+            build.verbose("running sanity check");
+            sanity::check(&mut build);
+        }
+
+        // If local-rust is the same major.minor as the current version, then force a
+        // local-rebuild
+        let local_version_verbose =
+            output(Command::new(&build.initial_rustc).arg("--version").arg("--verbose"));
+        let local_release = local_version_verbose
+            .lines()
+            .filter_map(|x| x.strip_prefix("release:"))
+            .next()
+            .unwrap()
+            .trim();
+        if local_release.split('.').take(2).eq(version.split('.').take(2)) {
+            build.verbose(&format!("auto-detected local-rebuild {}", local_release));
+            build.local_rebuild = true;
+        }
+
+        // Make sure we update these before gathering metadata so we don't get an error about missing
+        // Cargo.toml files.
+        let rust_submodules = [
+            "src/tools/rust-installer",
+            "src/tools/cargo",
+            "src/tools/rls",
+            "src/tools/miri",
+            "library/backtrace",
+            "library/stdarch",
+        ];
+        for s in rust_submodules {
+            build.update_submodule(Path::new(s));
+        }
+
+        build.verbose("learning about cargo");
+        metadata::build(&mut build);
+
+        build
+    }
+
+    // modified from `check_submodule` and `update_submodule` in bootstrap.py
+    /// Given a path to the directory of a submodule, update it.
+    ///
+    /// `relative_path` should be relative to the root of the git repository, not an absolute path.
+    pub(crate) fn update_submodule(&self, relative_path: &Path) {
+        fn dir_is_empty(dir: &Path) -> bool {
+            t!(std::fs::read_dir(dir)).next().is_none()
+        }
+
+        if !self.config.submodules(&self.rust_info) {
+            return;
+        }
+
+        let absolute_path = self.config.src.join(relative_path);
+
+        // NOTE: The check for the empty directory is here because when running x.py the first time,
+        // the submodule won't be checked out. Check it out now so we can build it.
+        if !channel::GitInfo::new(false, &absolute_path).is_git() && !dir_is_empty(&absolute_path) {
+            return;
+        }
+
+        // check_submodule
+        let checked_out_hash =
+            output(Command::new("git").args(&["rev-parse", "HEAD"]).current_dir(&absolute_path));
+        // update_submodules
+        let recorded = output(
+            Command::new("git")
+                .args(&["ls-tree", "HEAD"])
+                .arg(relative_path)
+                .current_dir(&self.config.src),
+        );
+        let actual_hash = recorded
+            .split_whitespace()
+            .nth(2)
+            .unwrap_or_else(|| panic!("unexpected output `{}`", recorded));
+
+        // update_submodule
+        if actual_hash == checked_out_hash.trim_end() {
+            // already checked out
+            return;
+        }
+
+        println!("Updating submodule {}", relative_path.display());
+        self.run(
+            Command::new("git")
+                .args(&["submodule", "-q", "sync"])
+                .arg(relative_path)
+                .current_dir(&self.config.src),
+        );
+
+        // Try passing `--progress` to start, then run git again without if that fails.
+        let update = |progress: bool| {
+            let mut git = Command::new("git");
+            git.args(&["submodule", "update", "--init", "--recursive", "--depth=1"]);
+            if progress {
+                git.arg("--progress");
+            }
+            git.arg(relative_path).current_dir(&self.config.src);
+            git
+        };
+        // NOTE: doesn't use `try_run` because this shouldn't print an error if it fails.
+        if !update(true).status().map_or(false, |status| status.success()) {
+            self.run(&mut update(false));
+        }
+
+        self.run(Command::new("git").args(&["reset", "-q", "--hard"]).current_dir(&absolute_path));
+        self.run(Command::new("git").args(&["clean", "-qdfx"]).current_dir(absolute_path));
+    }
+
+    /// If any submodule has been initialized already, sync it unconditionally.
+    /// This avoids contributors checking in a submodule change by accident.
+    pub fn maybe_update_submodules(&self) {
+        // Avoid running git when there isn't a git checkout.
+        if !self.config.submodules(&self.rust_info) {
+            return;
+        }
+        let output = output(
+            self.config
+                .git()
+                .args(&["config", "--file"])
+                .arg(&self.config.src.join(".gitmodules"))
+                .args(&["--get-regexp", "path"]),
+        );
+        for line in output.lines() {
+            // Look for `submodule.$name.path = $path`
+            // Sample output: `submodule.src/rust-installer.path src/tools/rust-installer`
+            let submodule = Path::new(line.splitn(2, ' ').nth(1).unwrap());
+            // Don't update the submodule unless it's already been cloned.
+            if channel::GitInfo::new(false, submodule).is_git() {
+                self.update_submodule(submodule);
+            }
+        }
+    }
+
+    /// Executes the entire build, as configured by the flags and configuration.
+    pub fn build(&mut self) {
+        unsafe {
+            job::setup(self);
+        }
+
+        self.maybe_update_submodules();
+
+        if let Subcommand::Format { check, paths } = &self.config.cmd {
+            return format::format(&builder::Builder::new(&self), *check, &paths);
+        }
+
+        if let Subcommand::Clean { all } = self.config.cmd {
+            return clean::clean(self, all);
+        }
+
+        if let Subcommand::Setup { profile } = &self.config.cmd {
+            return setup::setup(&self.config, *profile);
+        }
+
+        {
+            let builder = builder::Builder::new(&self);
+            if let Some(path) = builder.paths.get(0) {
+                if path == Path::new("nonexistent/path/to/trigger/cargo/metadata") {
+                    return;
+                }
+            }
+        }
+
+        if !self.config.dry_run {
+            {
+                self.config.dry_run = true;
+                let builder = builder::Builder::new(&self);
+                builder.execute_cli();
+            }
+            self.config.dry_run = false;
+            let builder = builder::Builder::new(&self);
+            builder.execute_cli();
+        } else {
+            let builder = builder::Builder::new(&self);
+            builder.execute_cli();
+        }
+
+        // Check for postponed failures from `test --no-fail-fast`.
+        let failures = self.delayed_failures.borrow();
+        if failures.len() > 0 {
+            eprintln!("\n{} command(s) did not execute successfully:\n", failures.len());
+            for failure in failures.iter() {
+                eprintln!("  - {}\n", failure);
+            }
+            detail_exit(1);
+        }
+
+        #[cfg(feature = "build-metrics")]
+        self.metrics.persist(self);
+    }
+
+    /// Clear out `dir` if `input` is newer.
+    ///
+    /// After this executes, it will also ensure that `dir` exists.
+    fn clear_if_dirty(&self, dir: &Path, input: &Path) -> bool {
+        let stamp = dir.join(".stamp");
+        let mut cleared = false;
+        if mtime(&stamp) < mtime(input) {
+            self.verbose(&format!("Dirty - {}", dir.display()));
+            let _ = fs::remove_dir_all(dir);
+            cleared = true;
+        } else if stamp.exists() {
+            return cleared;
+        }
+        t!(fs::create_dir_all(dir));
+        t!(File::create(stamp));
+        cleared
+    }
+
+    /// Gets the space-separated set of activated features for the standard
+    /// library.
+    fn std_features(&self, target: TargetSelection) -> String {
+        let mut features = "panic-unwind".to_string();
+
+        match self.config.llvm_libunwind(target) {
+            LlvmLibunwind::InTree => features.push_str(" llvm-libunwind"),
+            LlvmLibunwind::System => features.push_str(" system-llvm-libunwind"),
+            LlvmLibunwind::No => {}
+        }
+        if self.config.backtrace {
+            features.push_str(" backtrace");
+        }
+        if self.config.profiler_enabled(target) {
+            features.push_str(" profiler");
+        }
+        features
+    }
+
+    /// Gets the space-separated set of activated features for the compiler.
+    fn rustc_features(&self, kind: Kind) -> String {
+        let mut features = vec![];
+        if self.config.jemalloc {
+            features.push("jemalloc");
+        }
+        if self.config.llvm_enabled() || kind == Kind::Check {
+            features.push("llvm");
+        }
+        // keep in sync with `bootstrap/compile.rs:rustc_cargo_env`
+        if self.config.rustc_parallel {
+            features.push("rustc_use_parallel_compiler");
+        }
+
+        // If debug logging is on, then we want the default for tracing:
+        // https://github.com/tokio-rs/tracing/blob/3dd5c03d907afdf2c39444a29931833335171554/tracing/src/level_filters.rs#L26
+        // which is everything (including debug/trace/etc.)
+        // if its unset, if debug_assertions is on, then debug_logging will also be on
+        // as well as tracing *ignoring* this feature when debug_assertions is on
+        if !self.config.rust_debug_logging {
+            features.push("max_level_info");
+        }
+
+        features.join(" ")
+    }
+
+    /// Component directory that Cargo will produce output into (e.g.
+    /// release/debug)
+    fn cargo_dir(&self) -> &'static str {
+        if self.config.rust_optimize { "release" } else { "debug" }
+    }
+
+    fn tools_dir(&self, compiler: Compiler) -> PathBuf {
+        let out = self
+            .out
+            .join(&*compiler.host.triple)
+            .join(format!("stage{}-tools-bin", compiler.stage));
+        t!(fs::create_dir_all(&out));
+        out
+    }
+
+    /// Returns the root directory for all output generated in a particular
+    /// stage when running with a particular host compiler.
+    ///
+    /// The mode indicates what the root directory is for.
+    fn stage_out(&self, compiler: Compiler, mode: Mode) -> PathBuf {
+        let suffix = match mode {
+            Mode::Std => "-std",
+            Mode::Rustc => "-rustc",
+            Mode::Codegen => "-codegen",
+            Mode::ToolBootstrap => "-bootstrap-tools",
+            Mode::ToolStd | Mode::ToolRustc => "-tools",
+        };
+        self.out.join(&*compiler.host.triple).join(format!("stage{}{}", compiler.stage, suffix))
+    }
+
+    /// Returns the root output directory for all Cargo output in a given stage,
+    /// running a particular compiler, whether or not we're building the
+    /// standard library, and targeting the specified architecture.
+    fn cargo_out(&self, compiler: Compiler, mode: Mode, target: TargetSelection) -> PathBuf {
+        self.stage_out(compiler, mode).join(&*target.triple).join(self.cargo_dir())
+    }
+
+    /// Root output directory for LLVM compiled for `target`
+    ///
+    /// Note that if LLVM is configured externally then the directory returned
+    /// will likely be empty.
+    fn llvm_out(&self, target: TargetSelection) -> PathBuf {
+        self.out.join(&*target.triple).join("llvm")
+    }
+
+    fn lld_out(&self, target: TargetSelection) -> PathBuf {
+        self.out.join(&*target.triple).join("lld")
+    }
+
+    /// Output directory for all documentation for a target
+    fn doc_out(&self, target: TargetSelection) -> PathBuf {
+        self.out.join(&*target.triple).join("doc")
+    }
+
+    fn test_out(&self, target: TargetSelection) -> PathBuf {
+        self.out.join(&*target.triple).join("test")
+    }
+
+    /// Output directory for all documentation for a target
+    fn compiler_doc_out(&self, target: TargetSelection) -> PathBuf {
+        self.out.join(&*target.triple).join("compiler-doc")
+    }
+
+    /// Output directory for some generated md crate documentation for a target (temporary)
+    fn md_doc_out(&self, target: TargetSelection) -> Interned<PathBuf> {
+        INTERNER.intern_path(self.out.join(&*target.triple).join("md-doc"))
+    }
+
+    /// Returns `true` if no custom `llvm-config` is set for the specified target.
+    ///
+    /// If no custom `llvm-config` was specified then Rust's llvm will be used.
+    fn is_rust_llvm(&self, target: TargetSelection) -> bool {
+        if self.config.llvm_from_ci && target == self.config.build {
+            return true;
+        }
+
+        match self.config.target_config.get(&target) {
+            Some(ref c) => c.llvm_config.is_none(),
+            None => true,
+        }
+    }
+
+    /// Returns the path to `FileCheck` binary for the specified target
+    fn llvm_filecheck(&self, target: TargetSelection) -> PathBuf {
+        let target_config = self.config.target_config.get(&target);
+        if let Some(s) = target_config.and_then(|c| c.llvm_filecheck.as_ref()) {
+            s.to_path_buf()
+        } else if let Some(s) = target_config.and_then(|c| c.llvm_config.as_ref()) {
+            let llvm_bindir = output(Command::new(s).arg("--bindir"));
+            let filecheck = Path::new(llvm_bindir.trim()).join(exe("FileCheck", target));
+            if filecheck.exists() {
+                filecheck
+            } else {
+                // On Fedora the system LLVM installs FileCheck in the
+                // llvm subdirectory of the libdir.
+                let llvm_libdir = output(Command::new(s).arg("--libdir"));
+                let lib_filecheck =
+                    Path::new(llvm_libdir.trim()).join("llvm").join(exe("FileCheck", target));
+                if lib_filecheck.exists() {
+                    lib_filecheck
+                } else {
+                    // Return the most normal file name, even though
+                    // it doesn't exist, so that any error message
+                    // refers to that.
+                    filecheck
+                }
+            }
+        } else {
+            let base = self.llvm_out(target).join("build");
+            let base = if !self.ninja() && target.contains("msvc") {
+                if self.config.llvm_optimize {
+                    if self.config.llvm_release_debuginfo {
+                        base.join("RelWithDebInfo")
+                    } else {
+                        base.join("Release")
+                    }
+                } else {
+                    base.join("Debug")
+                }
+            } else {
+                base
+            };
+            base.join("bin").join(exe("FileCheck", target))
+        }
+    }
+
+    /// Directory for libraries built from C/C++ code and shared between stages.
+    fn native_dir(&self, target: TargetSelection) -> PathBuf {
+        self.out.join(&*target.triple).join("native")
+    }
+
+    /// Root output directory for rust_test_helpers library compiled for
+    /// `target`
+    fn test_helpers_out(&self, target: TargetSelection) -> PathBuf {
+        self.native_dir(target).join("rust-test-helpers")
+    }
+
+    /// Adds the `RUST_TEST_THREADS` env var if necessary
+    fn add_rust_test_threads(&self, cmd: &mut Command) {
+        if env::var_os("RUST_TEST_THREADS").is_none() {
+            cmd.env("RUST_TEST_THREADS", self.jobs().to_string());
+        }
+    }
+
+    /// Returns the libdir of the snapshot compiler.
+    fn rustc_snapshot_libdir(&self) -> PathBuf {
+        self.rustc_snapshot_sysroot().join(libdir(self.config.build))
+    }
+
+    /// Returns the sysroot of the snapshot compiler.
+    fn rustc_snapshot_sysroot(&self) -> &Path {
+        static SYSROOT_CACHE: OnceCell<PathBuf> = once_cell::sync::OnceCell::new();
+        SYSROOT_CACHE.get_or_init(|| {
+            let mut rustc = Command::new(&self.initial_rustc);
+            rustc.args(&["--print", "sysroot"]);
+            output(&mut rustc).trim().into()
+        })
+    }
+
+    /// Runs a command, printing out nice contextual information if it fails.
+    fn run(&self, cmd: &mut Command) {
+        if self.config.dry_run {
+            return;
+        }
+        self.verbose(&format!("running: {:?}", cmd));
+        run(cmd, self.is_verbose())
+    }
+
+    /// Runs a command, printing out nice contextual information if it fails.
+    fn run_quiet(&self, cmd: &mut Command) {
+        if self.config.dry_run {
+            return;
+        }
+        self.verbose(&format!("running: {:?}", cmd));
+        run_suppressed(cmd)
+    }
+
+    /// Runs a command, printing out nice contextual information if it fails.
+    /// Exits if the command failed to execute at all, otherwise returns its
+    /// `status.success()`.
+    fn try_run(&self, cmd: &mut Command) -> bool {
+        if self.config.dry_run {
+            return true;
+        }
+        self.verbose(&format!("running: {:?}", cmd));
+        try_run(cmd, self.is_verbose())
+    }
+
+    /// Runs a command, printing out nice contextual information if it fails.
+    /// Exits if the command failed to execute at all, otherwise returns its
+    /// `status.success()`.
+    fn try_run_quiet(&self, cmd: &mut Command) -> bool {
+        if self.config.dry_run {
+            return true;
+        }
+        self.verbose(&format!("running: {:?}", cmd));
+        try_run_suppressed(cmd)
+    }
+
+    /// Runs a command, printing out nice contextual information if it fails.
+    /// Returns false if do not execute at all, otherwise returns its
+    /// `status.success()`.
+    fn check_run(&self, cmd: &mut Command) -> bool {
+        if self.config.dry_run {
+            return true;
+        }
+        self.verbose(&format!("running: {:?}", cmd));
+        check_run(cmd, self.is_verbose())
+    }
+
+    pub fn is_verbose(&self) -> bool {
+        self.verbosity > 0
+    }
+
+    /// Prints a message if this build is configured in verbose mode.
+    fn verbose(&self, msg: &str) {
+        if self.is_verbose() {
+            println!("{}", msg);
+        }
+    }
+
+    pub fn is_verbose_than(&self, level: usize) -> bool {
+        self.verbosity > level
+    }
+
+    /// Prints a message if this build is configured in more verbose mode than `level`.
+    fn verbose_than(&self, level: usize, msg: &str) {
+        if self.is_verbose_than(level) {
+            println!("{}", msg);
+        }
+    }
+
+    fn info(&self, msg: &str) {
+        if self.config.dry_run {
+            return;
+        }
+        println!("{}", msg);
+    }
+
+    /// Returns the number of parallel jobs that have been configured for this
+    /// build.
+    fn jobs(&self) -> u32 {
+        self.config.jobs.unwrap_or_else(|| num_cpus::get() as u32)
+    }
+
+    fn debuginfo_map_to(&self, which: GitRepo) -> Option<String> {
+        if !self.config.rust_remap_debuginfo {
+            return None;
+        }
+
+        match which {
+            GitRepo::Rustc => {
+                let sha = self.rust_sha().unwrap_or(&self.version);
+                Some(format!("/rustc/{}", sha))
+            }
+            GitRepo::Llvm => Some(String::from("/rustc/llvm")),
+        }
+    }
+
+    /// Returns the path to the C compiler for the target specified.
+    fn cc(&self, target: TargetSelection) -> &Path {
+        self.cc[&target].path()
+    }
+
+    /// Returns a list of flags to pass to the C compiler for the target
+    /// specified.
+    fn cflags(&self, target: TargetSelection, which: GitRepo, c: CLang) -> Vec<String> {
+        let base = match c {
+            CLang::C => &self.cc[&target],
+            CLang::Cxx => &self.cxx[&target],
+        };
+
+        // Filter out -O and /O (the optimization flags) that we picked up from
+        // cc-rs because the build scripts will determine that for themselves.
+        let mut base = base
+            .args()
+            .iter()
+            .map(|s| s.to_string_lossy().into_owned())
+            .filter(|s| !s.starts_with("-O") && !s.starts_with("/O"))
+            .collect::<Vec<String>>();
+
+        // If we're compiling on macOS then we add a few unconditional flags
+        // indicating that we want libc++ (more filled out than libstdc++) and
+        // we want to compile for 10.7. This way we can ensure that
+        // LLVM/etc are all properly compiled.
+        if target.contains("apple-darwin") {
+            base.push("-stdlib=libc++".into());
+        }
+
+        // Work around an apparently bad MinGW / GCC optimization,
+        // See: https://lists.llvm.org/pipermail/cfe-dev/2016-December/051980.html
+        // See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78936
+        if &*target.triple == "i686-pc-windows-gnu" {
+            base.push("-fno-omit-frame-pointer".into());
+        }
+
+        if let Some(map_to) = self.debuginfo_map_to(which) {
+            let map = format!("{}={}", self.src.display(), map_to);
+            let cc = self.cc(target);
+            if cc.ends_with("clang") || cc.ends_with("gcc") {
+                base.push(format!("-fdebug-prefix-map={}", map));
+            } else if cc.ends_with("clang-cl.exe") {
+                base.push("-Xclang".into());
+                base.push(format!("-fdebug-prefix-map={}", map));
+            }
+        }
+        base
+    }
+
+    /// Returns the path to the `ar` archive utility for the target specified.
+    fn ar(&self, target: TargetSelection) -> Option<&Path> {
+        self.ar.get(&target).map(|p| &**p)
+    }
+
+    /// Returns the path to the `ranlib` utility for the target specified.
+    fn ranlib(&self, target: TargetSelection) -> Option<&Path> {
+        self.ranlib.get(&target).map(|p| &**p)
+    }
+
+    /// Returns the path to the C++ compiler for the target specified.
+    fn cxx(&self, target: TargetSelection) -> Result<&Path, String> {
+        match self.cxx.get(&target) {
+            Some(p) => Ok(p.path()),
+            None => {
+                Err(format!("target `{}` is not configured as a host, only as a target", target))
+            }
+        }
+    }
+
+    /// Returns the path to the linker for the given target if it needs to be overridden.
+    fn linker(&self, target: TargetSelection) -> Option<&Path> {
+        if let Some(linker) = self.config.target_config.get(&target).and_then(|c| c.linker.as_ref())
+        {
+            Some(linker)
+        } else if target.contains("vxworks") {
+            // need to use CXX compiler as linker to resolve the exception functions
+            // that are only existed in CXX libraries
+            Some(self.cxx[&target].path())
+        } else if target != self.config.build
+            && util::use_host_linker(target)
+            && !target.contains("msvc")
+        {
+            Some(self.cc(target))
+        } else if self.config.use_lld && !self.is_fuse_ld_lld(target) && self.build == target {
+            Some(&self.initial_lld)
+        } else {
+            None
+        }
+    }
+
+    // LLD is used through `-fuse-ld=lld` rather than directly.
+    // Only MSVC targets use LLD directly at the moment.
+    fn is_fuse_ld_lld(&self, target: TargetSelection) -> bool {
+        self.config.use_lld && !target.contains("msvc")
+    }
+
+    fn lld_flags(&self, target: TargetSelection) -> impl Iterator<Item = String> {
+        let mut options = [None, None];
+
+        if self.config.use_lld {
+            if self.is_fuse_ld_lld(target) {
+                options[0] = Some("-Clink-arg=-fuse-ld=lld".to_string());
+            }
+
+            let threads = if target.contains("windows") { "/threads:1" } else { "--threads=1" };
+            options[1] = Some(format!("-Clink-arg=-Wl,{}", threads));
+        }
+
+        IntoIterator::into_iter(options).flatten()
+    }
+
+    /// Returns if this target should statically link the C runtime, if specified
+    fn crt_static(&self, target: TargetSelection) -> Option<bool> {
+        if target.contains("pc-windows-msvc") {
+            Some(true)
+        } else {
+            self.config.target_config.get(&target).and_then(|t| t.crt_static)
+        }
+    }
+
+    /// Returns the "musl root" for this `target`, if defined
+    fn musl_root(&self, target: TargetSelection) -> Option<&Path> {
+        self.config
+            .target_config
+            .get(&target)
+            .and_then(|t| t.musl_root.as_ref())
+            .or_else(|| self.config.musl_root.as_ref())
+            .map(|p| &**p)
+    }
+
+    /// Returns the "musl libdir" for this `target`.
+    fn musl_libdir(&self, target: TargetSelection) -> Option<PathBuf> {
+        let t = self.config.target_config.get(&target)?;
+        if let libdir @ Some(_) = &t.musl_libdir {
+            return libdir.clone();
+        }
+        self.musl_root(target).map(|root| root.join("lib"))
+    }
+
+    /// Returns the sysroot for the wasi target, if defined
+    fn wasi_root(&self, target: TargetSelection) -> Option<&Path> {
+        self.config.target_config.get(&target).and_then(|t| t.wasi_root.as_ref()).map(|p| &**p)
+    }
+
+    /// Returns `true` if this is a no-std `target`, if defined
+    fn no_std(&self, target: TargetSelection) -> Option<bool> {
+        self.config.target_config.get(&target).map(|t| t.no_std)
+    }
+
+    /// Returns `true` if the target will be tested using the `remote-test-client`
+    /// and `remote-test-server` binaries.
+    fn remote_tested(&self, target: TargetSelection) -> bool {
+        self.qemu_rootfs(target).is_some()
+            || target.contains("android")
+            || env::var_os("TEST_DEVICE_ADDR").is_some()
+    }
+
+    /// Returns the root of the "rootfs" image that this target will be using,
+    /// if one was configured.
+    ///
+    /// If `Some` is returned then that means that tests for this target are
+    /// emulated with QEMU and binaries will need to be shipped to the emulator.
+    fn qemu_rootfs(&self, target: TargetSelection) -> Option<&Path> {
+        self.config.target_config.get(&target).and_then(|t| t.qemu_rootfs.as_ref()).map(|p| &**p)
+    }
+
+    /// Path to the python interpreter to use
+    fn python(&self) -> &Path {
+        if self.config.build.ends_with("apple-darwin") {
+            // Force /usr/bin/python3 on macOS for LLDB tests because we're loading the
+            // LLDB plugin's compiled module which only works with the system python
+            // (namely not Homebrew-installed python)
+            Path::new("/usr/bin/python3")
+        } else {
+            self.config
+                .python
+                .as_ref()
+                .expect("python is required for running LLDB or rustdoc tests")
+        }
+    }
+
+    /// Temporary directory that extended error information is emitted to.
+    fn extended_error_dir(&self) -> PathBuf {
+        self.out.join("tmp/extended-error-metadata")
+    }
+
+    /// Tests whether the `compiler` compiling for `target` should be forced to
+    /// use a stage1 compiler instead.
+    ///
+    /// Currently, by default, the build system does not perform a "full
+    /// bootstrap" by default where we compile the compiler three times.
+    /// Instead, we compile the compiler two times. The final stage (stage2)
+    /// just copies the libraries from the previous stage, which is what this
+    /// method detects.
+    ///
+    /// Here we return `true` if:
+    ///
+    /// * The build isn't performing a full bootstrap
+    /// * The `compiler` is in the final stage, 2
+    /// * We're not cross-compiling, so the artifacts are already available in
+    ///   stage1
+    ///
+    /// When all of these conditions are met the build will lift artifacts from
+    /// the previous stage forward.
+    fn force_use_stage1(&self, compiler: Compiler, target: TargetSelection) -> bool {
+        !self.config.full_bootstrap
+            && compiler.stage >= 2
+            && (self.hosts.iter().any(|h| *h == target) || target == self.build)
+    }
+
+    /// Given `num` in the form "a.b.c" return a "release string" which
+    /// describes the release version number.
+    ///
+    /// For example on nightly this returns "a.b.c-nightly", on beta it returns
+    /// "a.b.c-beta.1" and on stable it just returns "a.b.c".
+    fn release(&self, num: &str) -> String {
+        match &self.config.channel[..] {
+            "stable" => num.to_string(),
+            "beta" => {
+                if self.rust_info.is_git() && !self.config.ignore_git {
+                    format!("{}-beta.{}", num, self.beta_prerelease_version())
+                } else {
+                    format!("{}-beta", num)
+                }
+            }
+            "nightly" => format!("{}-nightly", num),
+            _ => format!("{}-dev", num),
+        }
+    }
+
+    fn beta_prerelease_version(&self) -> u32 {
+        if let Some(s) = self.prerelease_version.get() {
+            return s;
+        }
+
+        // Figure out how many merge commits happened since we branched off master.
+        // That's our beta number!
+        // (Note that we use a `..` range, not the `...` symmetric difference.)
+        let count =
+            output(self.config.git().arg("rev-list").arg("--count").arg("--merges").arg(format!(
+                "refs/remotes/origin/{}..HEAD",
+                self.config.stage0_metadata.config.nightly_branch
+            )));
+        let n = count.trim().parse().unwrap();
+        self.prerelease_version.set(Some(n));
+        n
+    }
+
+    /// Returns the value of `release` above for Rust itself.
+    fn rust_release(&self) -> String {
+        self.release(&self.version)
+    }
+
+    /// Returns the "package version" for a component given the `num` release
+    /// number.
+    ///
+    /// The package version is typically what shows up in the names of tarballs.
+    /// For channels like beta/nightly it's just the channel name, otherwise
+    /// it's the `num` provided.
+    fn package_vers(&self, num: &str) -> String {
+        match &self.config.channel[..] {
+            "stable" => num.to_string(),
+            "beta" => "beta".to_string(),
+            "nightly" => "nightly".to_string(),
+            _ => format!("{}-dev", num),
+        }
+    }
+
+    /// Returns the value of `package_vers` above for Rust itself.
+    fn rust_package_vers(&self) -> String {
+        self.package_vers(&self.version)
+    }
+
+    fn llvm_link_tools_dynamically(&self, target: TargetSelection) -> bool {
+        target.contains("linux-gnu") || target.contains("apple-darwin")
+    }
+
+    /// Returns the `version` string associated with this compiler for Rust
+    /// itself.
+    ///
+    /// Note that this is a descriptive string which includes the commit date,
+    /// sha, version, etc.
+    fn rust_version(&self) -> String {
+        let mut version = self.rust_info.version(self, &self.version);
+        if let Some(ref s) = self.config.description {
+            version.push_str(" (");
+            version.push_str(s);
+            version.push(')');
+        }
+        version
+    }
+
+    /// Returns the full commit hash.
+    fn rust_sha(&self) -> Option<&str> {
+        self.rust_info.sha()
+    }
+
+    /// Returns the `a.b.c` version that the given package is at.
+    fn release_num(&self, package: &str) -> String {
+        let toml_file_name = self.src.join(&format!("src/tools/{}/Cargo.toml", package));
+        let toml = t!(fs::read_to_string(&toml_file_name));
+        for line in toml.lines() {
+            if let Some(stripped) =
+                line.strip_prefix("version = \"").and_then(|s| s.strip_suffix("\""))
+            {
+                return stripped.to_owned();
+            }
+        }
+
+        panic!("failed to find version in {}'s Cargo.toml", package)
+    }
+
+    /// Returns `true` if unstable features should be enabled for the compiler
+    /// we're building.
+    fn unstable_features(&self) -> bool {
+        match &self.config.channel[..] {
+            "stable" | "beta" => false,
+            "nightly" | _ => true,
+        }
+    }
+
+    /// Returns a Vec of all the dependencies of the given root crate,
+    /// including transitive dependencies and the root itself. Only includes
+    /// "local" crates (those in the local source tree, not from a registry).
+    fn in_tree_crates(&self, root: &str, target: Option<TargetSelection>) -> Vec<&Crate> {
+        let mut ret = Vec::new();
+        let mut list = vec![INTERNER.intern_str(root)];
+        let mut visited = HashSet::new();
+        while let Some(krate) = list.pop() {
+            let krate = &self.crates[&krate];
+            ret.push(krate);
+            for dep in &krate.deps {
+                if !self.crates.contains_key(dep) {
+                    // Ignore non-workspace members.
+                    continue;
+                }
+                // Don't include optional deps if their features are not
+                // enabled. Ideally this would be computed from `cargo
+                // metadata --features …`, but that is somewhat slow. In
+                // the future, we may want to consider just filtering all
+                // build and dev dependencies in metadata::build.
+                if visited.insert(dep)
+                    && (dep != "profiler_builtins"
+                        || target
+                            .map(|t| self.config.profiler_enabled(t))
+                            .unwrap_or_else(|| self.config.any_profiler_enabled()))
+                    && (dep != "rustc_codegen_llvm" || self.config.llvm_enabled())
+                {
+                    list.push(*dep);
+                }
+            }
+        }
+        ret
+    }
+
+    fn read_stamp_file(&self, stamp: &Path) -> Vec<(PathBuf, DependencyType)> {
+        if self.config.dry_run {
+            return Vec::new();
+        }
+
+        let mut paths = Vec::new();
+        let contents = t!(fs::read(stamp), &stamp);
+        // This is the method we use for extracting paths from the stamp file passed to us. See
+        // run_cargo for more information (in compile.rs).
+        for part in contents.split(|b| *b == 0) {
+            if part.is_empty() {
+                continue;
+            }
+            let dependency_type = match part[0] as char {
+                'h' => DependencyType::Host,
+                's' => DependencyType::TargetSelfContained,
+                't' => DependencyType::Target,
+                _ => unreachable!(),
+            };
+            let path = PathBuf::from(t!(str::from_utf8(&part[1..])));
+            paths.push((path, dependency_type));
+        }
+        paths
+    }
+
+    /// Create a temporary directory in `out` and return its path.
+    ///
+    /// NOTE: this temporary directory is shared between all steps;
+    /// if you need an empty directory, create a new subdirectory inside it.
+    fn tempdir(&self) -> PathBuf {
+        let tmp = self.out.join("tmp");
+        t!(fs::create_dir_all(&tmp));
+        tmp
+    }
+
+    /// Copies a file from `src` to `dst`
+    pub fn copy(&self, src: &Path, dst: &Path) {
+        self.copy_internal(src, dst, false);
+    }
+
+    fn copy_internal(&self, src: &Path, dst: &Path, dereference_symlinks: bool) {
+        if self.config.dry_run {
+            return;
+        }
+        self.verbose_than(1, &format!("Copy {:?} to {:?}", src, dst));
+        if src == dst {
+            return;
+        }
+        let _ = fs::remove_file(&dst);
+        let metadata = t!(src.symlink_metadata());
+        let mut src = src.to_path_buf();
+        if metadata.file_type().is_symlink() {
+            if dereference_symlinks {
+                src = t!(fs::canonicalize(src));
+            } else {
+                let link = t!(fs::read_link(src));
+                t!(self.symlink_file(link, dst));
+                return;
+            }
+        }
+        if let Ok(()) = fs::hard_link(&src, dst) {
+            // Attempt to "easy copy" by creating a hard link
+            // (symlinks don't work on windows), but if that fails
+            // just fall back to a slow `copy` operation.
+        } else {
+            if let Err(e) = fs::copy(&src, dst) {
+                panic!("failed to copy `{}` to `{}`: {}", src.display(), dst.display(), e)
+            }
+            t!(fs::set_permissions(dst, metadata.permissions()));
+            let atime = FileTime::from_last_access_time(&metadata);
+            let mtime = FileTime::from_last_modification_time(&metadata);
+            t!(filetime::set_file_times(dst, atime, mtime));
+        }
+    }
+
+    /// Copies the `src` directory recursively to `dst`. Both are assumed to exist
+    /// when this function is called.
+    pub fn cp_r(&self, src: &Path, dst: &Path) {
+        if self.config.dry_run {
+            return;
+        }
+        for f in self.read_dir(src) {
+            let path = f.path();
+            let name = path.file_name().unwrap();
+            let dst = dst.join(name);
+            if t!(f.file_type()).is_dir() {
+                t!(fs::create_dir_all(&dst));
+                self.cp_r(&path, &dst);
+            } else {
+                let _ = fs::remove_file(&dst);
+                self.copy(&path, &dst);
+            }
+        }
+    }
+
+    /// Copies the `src` directory recursively to `dst`. Both are assumed to exist
+    /// when this function is called. Unwanted files or directories can be skipped
+    /// by returning `false` from the filter function.
+    pub fn cp_filtered(&self, src: &Path, dst: &Path, filter: &dyn Fn(&Path) -> bool) {
+        // Immediately recurse with an empty relative path
+        self.recurse_(src, dst, Path::new(""), filter)
+    }
+
+    // Inner function does the actual work
+    fn recurse_(&self, src: &Path, dst: &Path, relative: &Path, filter: &dyn Fn(&Path) -> bool) {
+        for f in self.read_dir(src) {
+            let path = f.path();
+            let name = path.file_name().unwrap();
+            let dst = dst.join(name);
+            let relative = relative.join(name);
+            // Only copy file or directory if the filter function returns true
+            if filter(&relative) {
+                if t!(f.file_type()).is_dir() {
+                    let _ = fs::remove_dir_all(&dst);
+                    self.create_dir(&dst);
+                    self.recurse_(&path, &dst, &relative, filter);
+                } else {
+                    let _ = fs::remove_file(&dst);
+                    self.copy(&path, &dst);
+                }
+            }
+        }
+    }
+
+    fn copy_to_folder(&self, src: &Path, dest_folder: &Path) {
+        let file_name = src.file_name().unwrap();
+        let dest = dest_folder.join(file_name);
+        self.copy(src, &dest);
+    }
+
+    fn install(&self, src: &Path, dstdir: &Path, perms: u32) {
+        if self.config.dry_run {
+            return;
+        }
+        let dst = dstdir.join(src.file_name().unwrap());
+        self.verbose_than(1, &format!("Install {:?} to {:?}", src, dst));
+        t!(fs::create_dir_all(dstdir));
+        if !src.exists() {
+            panic!("Error: File \"{}\" not found!", src.display());
+        }
+        self.copy_internal(src, &dst, true);
+        chmod(&dst, perms);
+    }
+
+    fn create(&self, path: &Path, s: &str) {
+        if self.config.dry_run {
+            return;
+        }
+        t!(fs::write(path, s));
+    }
+
+    fn read(&self, path: &Path) -> String {
+        if self.config.dry_run {
+            return String::new();
+        }
+        t!(fs::read_to_string(path))
+    }
+
+    fn create_dir(&self, dir: &Path) {
+        if self.config.dry_run {
+            return;
+        }
+        t!(fs::create_dir_all(dir))
+    }
+
+    fn remove_dir(&self, dir: &Path) {
+        if self.config.dry_run {
+            return;
+        }
+        t!(fs::remove_dir_all(dir))
+    }
+
+    fn read_dir(&self, dir: &Path) -> impl Iterator<Item = fs::DirEntry> {
+        let iter = match fs::read_dir(dir) {
+            Ok(v) => v,
+            Err(_) if self.config.dry_run => return vec![].into_iter(),
+            Err(err) => panic!("could not read dir {:?}: {:?}", dir, err),
+        };
+        iter.map(|e| t!(e)).collect::<Vec<_>>().into_iter()
+    }
+
+    fn symlink_file<P: AsRef<Path>, Q: AsRef<Path>>(&self, src: P, link: Q) -> io::Result<()> {
+        #[cfg(unix)]
+        use std::os::unix::fs::symlink as symlink_file;
+        #[cfg(windows)]
+        use std::os::windows::fs::symlink_file;
+        if !self.config.dry_run { symlink_file(src.as_ref(), link.as_ref()) } else { Ok(()) }
+    }
+
+    fn remove(&self, f: &Path) {
+        if self.config.dry_run {
+            return;
+        }
+        fs::remove_file(f).unwrap_or_else(|_| panic!("failed to remove {:?}", f));
+    }
+
+    /// Returns if config.ninja is enabled, and checks for ninja existence,
+    /// exiting with a nicer error message if not.
+    fn ninja(&self) -> bool {
+        let mut cmd_finder = crate::sanity::Finder::new();
+
+        if self.config.ninja_in_file {
+            // Some Linux distros rename `ninja` to `ninja-build`.
+            // CMake can work with either binary name.
+            if cmd_finder.maybe_have("ninja-build").is_none()
+                && cmd_finder.maybe_have("ninja").is_none()
+            {
+                eprintln!(
+                    "
+Couldn't find required command: ninja (or ninja-build)
+
+You should install ninja as described at
+<https://github.com/ninja-build/ninja/wiki/Pre-built-Ninja-packages>,
+or set `ninja = false` in the `[llvm]` section of `config.toml`.
+Alternatively, set `download-ci-llvm = true` in that `[llvm]` section
+to download LLVM rather than building it.
+"
+                );
+                detail_exit(1);
+            }
+        }
+
+        // If ninja isn't enabled but we're building for MSVC then we try
+        // doubly hard to enable it. It was realized in #43767 that the msbuild
+        // CMake generator for MSVC doesn't respect configuration options like
+        // disabling LLVM assertions, which can often be quite important!
+        //
+        // In these cases we automatically enable Ninja if we find it in the
+        // environment.
+        if !self.config.ninja_in_file && self.config.build.contains("msvc") {
+            if cmd_finder.maybe_have("ninja").is_some() {
+                return true;
+            }
+        }
+
+        self.config.ninja_in_file
+    }
+}
+
+#[cfg(unix)]
+fn chmod(path: &Path, perms: u32) {
+    use std::os::unix::fs::*;
+    t!(fs::set_permissions(path, fs::Permissions::from_mode(perms)));
+}
+#[cfg(windows)]
+fn chmod(_path: &Path, _perms: u32) {}
+
+/// If code is not 0 (successful exit status), exit status is 101 (rust's default error code.)
+/// If the test is running and code is an error code, it will cause a panic.
+fn detail_exit(code: i32) -> ! {
+    // Successful exit
+    if code == 0 {
+        std::process::exit(0);
+    }
+    if cfg!(test) {
+        panic!("status code: {}", code);
+    } else {
+        std::panic::resume_unwind(Box::new(code));
+    }
+}
+
+impl Compiler {
+    pub fn with_stage(mut self, stage: u32) -> Compiler {
+        self.stage = stage;
+        self
+    }
+
+    /// Returns `true` if this is a snapshot compiler for `build`'s configuration
+    pub fn is_snapshot(&self, build: &Build) -> bool {
+        self.stage == 0 && self.host == build.build
+    }
+
+    /// Returns if this compiler should be treated as a final stage one in the
+    /// current build session.
+    /// This takes into account whether we're performing a full bootstrap or
+    /// not; don't directly compare the stage with `2`!
+    pub fn is_final_stage(&self, build: &Build) -> bool {
+        let final_stage = if build.config.full_bootstrap { 2 } else { 1 };
+        self.stage >= final_stage
+    }
+}
+
+fn envify(s: &str) -> String {
+    s.chars()
+        .map(|c| match c {
+            '-' => '_',
+            c => c,
+        })
+        .flat_map(|c| c.to_uppercase())
+        .collect()
+}