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

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

5 files changed, 612 insertions, 0 deletions

diff --git a/src/bootstrap/bin/llvm-config-wrapper.rs b/src/bootstrap/bin/llvm-config-wrapper.rs
new file mode 100644
index 000000000..89984bb55
--- /dev/null
+++ b/src/bootstrap/bin/llvm-config-wrapper.rs
@@ -0,0 +1,24 @@
+// The sheer existence of this file is an awful hack. See the comments in
+// `src/bootstrap/native.rs` for why this is needed when compiling LLD.
+
+use std::env;
+use std::io::{self, Write};
+use std::process::{self, Command, Stdio};
+
+fn main() {
+    let real_llvm_config = env::var_os("LLVM_CONFIG_REAL").unwrap();
+    let mut cmd = Command::new(real_llvm_config);
+    cmd.args(env::args().skip(1)).stderr(Stdio::piped());
+    let output = cmd.output().expect("failed to spawn llvm-config");
+    let mut stdout = String::from_utf8_lossy(&output.stdout);
+
+    if let Ok(to_replace) = env::var("LLVM_CONFIG_SHIM_REPLACE") {
+        if let Ok(replace_with) = env::var("LLVM_CONFIG_SHIM_REPLACE_WITH") {
+            stdout = stdout.replace(&to_replace, &replace_with).into();
+        }
+    }
+
+    print!("{}", stdout.replace("\\", "/"));
+    io::stdout().flush().unwrap();
+    process::exit(output.status.code().unwrap_or(1));
+}
diff --git a/src/bootstrap/bin/main.rs b/src/bootstrap/bin/main.rs
new file mode 100644
index 000000000..9b4861ccd
--- /dev/null
+++ b/src/bootstrap/bin/main.rs
@@ -0,0 +1,100 @@
+//! rustbuild, the Rust build system
+//!
+//! This is the entry point for the build system used to compile the `rustc`
+//! compiler. Lots of documentation can be found in the `README.md` file in the
+//! parent directory, and otherwise documentation can be found throughout the `build`
+//! directory in each respective module.
+
+use std::env;
+
+use bootstrap::{t, Build, Config, Subcommand, VERSION};
+
+fn main() {
+    let args = env::args().skip(1).collect::<Vec<_>>();
+    let config = Config::parse(&args);
+
+    let mut build_lock;
+    let _build_lock_guard;
+    if cfg!(any(unix, windows)) {
+        build_lock = fd_lock::RwLock::new(t!(std::fs::File::create(config.out.join("lock"))));
+        _build_lock_guard = match build_lock.try_write() {
+            Ok(lock) => lock,
+            err => {
+                println!("warning: build directory locked, waiting for lock");
+                drop(err);
+                t!(build_lock.write())
+            }
+        };
+    } else {
+        println!("warning: file locking not supported for target, not locking build directory");
+    }
+
+    // check_version warnings are not printed during setup
+    let changelog_suggestion =
+        if matches!(config.cmd, Subcommand::Setup { .. }) { None } else { check_version(&config) };
+
+    // NOTE: Since `./configure` generates a `config.toml`, distro maintainers will see the
+    // changelog warning, not the `x.py setup` message.
+    let suggest_setup = !config.config.exists() && !matches!(config.cmd, Subcommand::Setup { .. });
+    if suggest_setup {
+        println!("warning: you have not made a `config.toml`");
+        println!(
+            "help: consider running `./x.py setup` or copying `config.toml.example` by running \
+            `cp config.toml.example config.toml`"
+        );
+    } else if let Some(suggestion) = &changelog_suggestion {
+        println!("{}", suggestion);
+    }
+
+    let pre_commit = config.src.join(".git").join("hooks").join("pre-commit");
+    Build::new(config).build();
+
+    if suggest_setup {
+        println!("warning: you have not made a `config.toml`");
+        println!(
+            "help: consider running `./x.py setup` or copying `config.toml.example` by running \
+            `cp config.toml.example config.toml`"
+        );
+    } else if let Some(suggestion) = &changelog_suggestion {
+        println!("{}", suggestion);
+    }
+
+    // Give a warning if the pre-commit script is in pre-commit and not pre-push.
+    // HACK: Since the commit script uses hard links, we can't actually tell if it was installed by x.py setup or not.
+    // We could see if it's identical to src/etc/pre-push.sh, but pre-push may have been modified in the meantime.
+    // Instead, look for this comment, which is almost certainly not in any custom hook.
+    if std::fs::read_to_string(pre_commit).map_or(false, |contents| {
+        contents.contains("https://github.com/rust-lang/rust/issues/77620#issuecomment-705144570")
+    }) {
+        println!(
+            "warning: You have the pre-push script installed to .git/hooks/pre-commit. \
+                  Consider moving it to .git/hooks/pre-push instead, which runs less often."
+        );
+    }
+
+    if suggest_setup || changelog_suggestion.is_some() {
+        println!("note: this message was printed twice to make it more likely to be seen");
+    }
+}
+
+fn check_version(config: &Config) -> Option<String> {
+    let mut msg = String::new();
+
+    let suggestion = if let Some(seen) = config.changelog_seen {
+        if seen != VERSION {
+            msg.push_str("warning: there have been changes to x.py since you last updated.\n");
+            format!("update `config.toml` to use `changelog-seen = {}` instead", VERSION)
+        } else {
+            return None;
+        }
+    } else {
+        msg.push_str("warning: x.py has made several changes recently you may want to look at\n");
+        format!("add `changelog-seen = {}` at the top of `config.toml`", VERSION)
+    };
+
+    msg.push_str("help: consider looking at the changes in `src/bootstrap/CHANGELOG.md`\n");
+    msg.push_str("note: to silence this warning, ");
+    msg.push_str(&suggestion);
+
+    Some(msg)
+}
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
new file mode 100644
index 000000000..40a3cc6d1
--- /dev/null
+++ b/src/bootstrap/bin/rustc.rs
@@ -0,0 +1,369 @@
+//! Shim which is passed to Cargo as "rustc" when running the bootstrap.
+//!
+//! This shim will take care of some various tasks that our build process
+//! requires that Cargo can't quite do through normal configuration:
+//!
+//! 1. When compiling build scripts and build dependencies, we need a guaranteed
+//!    full standard library available. The only compiler which actually has
+//!    this is the snapshot, so we detect this situation and always compile with
+//!    the snapshot compiler.
+//! 2. We pass a bunch of `--cfg` and other flags based on what we're compiling
+//!    (and this slightly differs based on a whether we're using a snapshot or
+//!    not), so we do that all here.
+//!
+//! This may one day be replaced by RUSTFLAGS, but the dynamic nature of
+//! switching compilers for the bootstrap and for build scripts will probably
+//! never get replaced.
+
+include!("../dylib_util.rs");
+
+use std::env;
+use std::path::PathBuf;
+use std::process::{Child, Command};
+use std::str::FromStr;
+use std::time::Instant;
+
+fn main() {
+    let args = env::args_os().skip(1).collect::<Vec<_>>();
+
+    // Detect whether or not we're a build script depending on whether --target
+    // is passed (a bit janky...)
+    let target = args.windows(2).find(|w| &*w[0] == "--target").and_then(|w| w[1].to_str());
+    let version = args.iter().find(|w| &**w == "-vV");
+
+    let verbose = match env::var("RUSTC_VERBOSE") {
+        Ok(s) => usize::from_str(&s).expect("RUSTC_VERBOSE should be an integer"),
+        Err(_) => 0,
+    };
+
+    // Use a different compiler for build scripts, since there may not yet be a
+    // libstd for the real compiler to use. However, if Cargo is attempting to
+    // determine the version of the compiler, the real compiler needs to be
+    // used. Currently, these two states are differentiated based on whether
+    // --target and -vV is/isn't passed.
+    let (rustc, libdir) = if target.is_none() && version.is_none() {
+        ("RUSTC_SNAPSHOT", "RUSTC_SNAPSHOT_LIBDIR")
+    } else {
+        ("RUSTC_REAL", "RUSTC_LIBDIR")
+    };
+    let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
+    let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
+    let on_fail = env::var_os("RUSTC_ON_FAIL").map(Command::new);
+
+    let rustc = env::var_os(rustc).unwrap_or_else(|| panic!("{:?} was not set", rustc));
+    let libdir = env::var_os(libdir).unwrap_or_else(|| panic!("{:?} was not set", libdir));
+    let mut dylib_path = dylib_path();
+    dylib_path.insert(0, PathBuf::from(&libdir));
+
+    let mut cmd = Command::new(rustc);
+    cmd.args(&args).env(dylib_path_var(), env::join_paths(&dylib_path).unwrap());
+
+    // Get the name of the crate we're compiling, if any.
+    let crate_name =
+        args.windows(2).find(|args| args[0] == "--crate-name").and_then(|args| args[1].to_str());
+
+    if let Some(crate_name) = crate_name {
+        if let Some(target) = env::var_os("RUSTC_TIME") {
+            if target == "all"
+                || target.into_string().unwrap().split(',').any(|c| c.trim() == crate_name)
+            {
+                cmd.arg("-Ztime");
+            }
+        }
+    }
+
+    // Print backtrace in case of ICE
+    if env::var("RUSTC_BACKTRACE_ON_ICE").is_ok() && env::var("RUST_BACKTRACE").is_err() {
+        cmd.env("RUST_BACKTRACE", "1");
+    }
+
+    if let Ok(lint_flags) = env::var("RUSTC_LINT_FLAGS") {
+        cmd.args(lint_flags.split_whitespace());
+    }
+
+    if target.is_some() {
+        // The stage0 compiler has a special sysroot distinct from what we
+        // actually downloaded, so we just always pass the `--sysroot` option,
+        // unless one is already set.
+        if !args.iter().any(|arg| arg == "--sysroot") {
+            cmd.arg("--sysroot").arg(&sysroot);
+        }
+
+        // If we're compiling specifically the `panic_abort` crate then we pass
+        // the `-C panic=abort` option. Note that we do not do this for any
+        // other crate intentionally as this is the only crate for now that we
+        // ship with panic=abort.
+        //
+        // This... is a bit of a hack how we detect this. Ideally this
+        // information should be encoded in the crate I guess? Would likely
+        // require an RFC amendment to RFC 1513, however.
+        //
+        // `compiler_builtins` are unconditionally compiled with panic=abort to
+        // workaround undefined references to `rust_eh_unwind_resume` generated
+        // otherwise, see issue https://github.com/rust-lang/rust/issues/43095.
+        if crate_name == Some("panic_abort")
+            || crate_name == Some("compiler_builtins") && stage != "0"
+        {
+            cmd.arg("-C").arg("panic=abort");
+        }
+    } else {
+        // FIXME(rust-lang/cargo#5754) we shouldn't be using special env vars
+        // here, but rather Cargo should know what flags to pass rustc itself.
+
+        // Override linker if necessary.
+        if let Ok(host_linker) = env::var("RUSTC_HOST_LINKER") {
+            cmd.arg(format!("-Clinker={}", host_linker));
+        }
+        if env::var_os("RUSTC_HOST_FUSE_LD_LLD").is_some() {
+            cmd.arg("-Clink-args=-fuse-ld=lld");
+        }
+
+        if let Ok(s) = env::var("RUSTC_HOST_CRT_STATIC") {
+            if s == "true" {
+                cmd.arg("-C").arg("target-feature=+crt-static");
+            }
+            if s == "false" {
+                cmd.arg("-C").arg("target-feature=-crt-static");
+            }
+        }
+
+        // Cargo doesn't pass RUSTFLAGS to proc_macros:
+        // https://github.com/rust-lang/cargo/issues/4423
+        // Thus, if we are on stage 0, we explicitly set `--cfg=bootstrap`.
+        // We also declare that the flag is expected, which is mainly needed for
+        // later stages so that they don't warn about #[cfg(bootstrap)],
+        // but enabling it for stage 0 too lets any warnings, if they occur,
+        // occur more early on, e.g. about #[cfg(bootstrap = "foo")].
+        if stage == "0" {
+            cmd.arg("--cfg=bootstrap");
+        }
+        cmd.arg("-Zunstable-options");
+        cmd.arg("--check-cfg=values(bootstrap)");
+    }
+
+    if let Ok(map) = env::var("RUSTC_DEBUGINFO_MAP") {
+        cmd.arg("--remap-path-prefix").arg(&map);
+    }
+
+    // Force all crates compiled by this compiler to (a) be unstable and (b)
+    // allow the `rustc_private` feature to link to other unstable crates
+    // also in the sysroot. We also do this for host crates, since those
+    // may be proc macros, in which case we might ship them.
+    if env::var_os("RUSTC_FORCE_UNSTABLE").is_some() && (stage != "0" || target.is_some()) {
+        cmd.arg("-Z").arg("force-unstable-if-unmarked");
+    }
+
+    if let Ok(flags) = env::var("MAGIC_EXTRA_RUSTFLAGS") {
+        for flag in flags.split(' ') {
+            cmd.arg(flag);
+        }
+    }
+
+    let is_test = args.iter().any(|a| a == "--test");
+    if verbose > 2 {
+        let rust_env_vars =
+            env::vars().filter(|(k, _)| k.starts_with("RUST") || k.starts_with("CARGO"));
+        let prefix = if is_test { "[RUSTC-SHIM] rustc --test" } else { "[RUSTC-SHIM] rustc" };
+        let prefix = match crate_name {
+            Some(crate_name) => format!("{} {}", prefix, crate_name),
+            None => prefix.to_string(),
+        };
+        for (i, (k, v)) in rust_env_vars.enumerate() {
+            eprintln!("{} env[{}]: {:?}={:?}", prefix, i, k, v);
+        }
+        eprintln!("{} working directory: {}", prefix, env::current_dir().unwrap().display());
+        eprintln!(
+            "{} command: {:?}={:?} {:?}",
+            prefix,
+            dylib_path_var(),
+            env::join_paths(&dylib_path).unwrap(),
+            cmd,
+        );
+        eprintln!("{} sysroot: {:?}", prefix, sysroot);
+        eprintln!("{} libdir: {:?}", prefix, libdir);
+    }
+
+    let start = Instant::now();
+    let (child, status) = {
+        let errmsg = format!("\nFailed to run:\n{:?}\n-------------", cmd);
+        let mut child = cmd.spawn().expect(&errmsg);
+        let status = child.wait().expect(&errmsg);
+        (child, status)
+    };
+
+    if env::var_os("RUSTC_PRINT_STEP_TIMINGS").is_some()
+        || env::var_os("RUSTC_PRINT_STEP_RUSAGE").is_some()
+    {
+        if let Some(crate_name) = crate_name {
+            let dur = start.elapsed();
+            // If the user requested resource usage data, then
+            // include that in addition to the timing output.
+            let rusage_data =
+                env::var_os("RUSTC_PRINT_STEP_RUSAGE").and_then(|_| format_rusage_data(child));
+            eprintln!(
+                "[RUSTC-TIMING] {} test:{} {}.{:03}{}{}",
+                crate_name,
+                is_test,
+                dur.as_secs(),
+                dur.subsec_millis(),
+                if rusage_data.is_some() { " " } else { "" },
+                rusage_data.unwrap_or(String::new()),
+            );
+        }
+    }
+
+    if status.success() {
+        std::process::exit(0);
+        // note: everything below here is unreachable. do not put code that
+        // should run on success, after this block.
+    }
+    if verbose > 0 {
+        println!("\nDid not run successfully: {}\n{:?}\n-------------", status, cmd);
+    }
+
+    if let Some(mut on_fail) = on_fail {
+        on_fail.status().expect("Could not run the on_fail command");
+    }
+
+    // Preserve the exit code. In case of signal, exit with 0xfe since it's
+    // awkward to preserve this status in a cross-platform way.
+    match status.code() {
+        Some(i) => std::process::exit(i),
+        None => {
+            eprintln!("rustc exited with {}", status);
+            std::process::exit(0xfe);
+        }
+    }
+}
+
+#[cfg(all(not(unix), not(windows)))]
+// In the future we can add this for more platforms
+fn format_rusage_data(_child: Child) -> Option<String> {
+    None
+}
+
+#[cfg(windows)]
+fn format_rusage_data(child: Child) -> Option<String> {
+    use std::os::windows::io::AsRawHandle;
+    use winapi::um::{processthreadsapi, psapi, timezoneapi};
+    let handle = child.as_raw_handle();
+    macro_rules! try_bool {
+        ($e:expr) => {
+            if $e != 1 {
+                return None;
+            }
+        };
+    }
+
+    let mut user_filetime = Default::default();
+    let mut user_time = Default::default();
+    let mut kernel_filetime = Default::default();
+    let mut kernel_time = Default::default();
+    let mut memory_counters = psapi::PROCESS_MEMORY_COUNTERS::default();
+
+    unsafe {
+        try_bool!(processthreadsapi::GetProcessTimes(
+            handle,
+            &mut Default::default(),
+            &mut Default::default(),
+            &mut kernel_filetime,
+            &mut user_filetime,
+        ));
+        try_bool!(timezoneapi::FileTimeToSystemTime(&user_filetime, &mut user_time));
+        try_bool!(timezoneapi::FileTimeToSystemTime(&kernel_filetime, &mut kernel_time));
+
+        // Unlike on Linux with RUSAGE_CHILDREN, this will only return memory information for the process
+        // with the given handle and none of that process's children.
+        try_bool!(psapi::GetProcessMemoryInfo(
+            handle as _,
+            &mut memory_counters as *mut _ as _,
+            std::mem::size_of::<psapi::PROCESS_MEMORY_COUNTERS_EX>() as u32,
+        ));
+    }
+
+    // Guide on interpreting these numbers:
+    // https://docs.microsoft.com/en-us/windows/win32/psapi/process-memory-usage-information
+    let peak_working_set = memory_counters.PeakWorkingSetSize / 1024;
+    let peak_page_file = memory_counters.PeakPagefileUsage / 1024;
+    let peak_paged_pool = memory_counters.QuotaPeakPagedPoolUsage / 1024;
+    let peak_nonpaged_pool = memory_counters.QuotaPeakNonPagedPoolUsage / 1024;
+    Some(format!(
+        "user: {USER_SEC}.{USER_USEC:03} \
+         sys: {SYS_SEC}.{SYS_USEC:03} \
+         peak working set (kb): {PEAK_WORKING_SET} \
+         peak page file usage (kb): {PEAK_PAGE_FILE} \
+         peak paged pool usage (kb): {PEAK_PAGED_POOL} \
+         peak non-paged pool usage (kb): {PEAK_NONPAGED_POOL} \
+         page faults: {PAGE_FAULTS}",
+        USER_SEC = user_time.wSecond + (user_time.wMinute * 60),
+        USER_USEC = user_time.wMilliseconds,
+        SYS_SEC = kernel_time.wSecond + (kernel_time.wMinute * 60),
+        SYS_USEC = kernel_time.wMilliseconds,
+        PEAK_WORKING_SET = peak_working_set,
+        PEAK_PAGE_FILE = peak_page_file,
+        PEAK_PAGED_POOL = peak_paged_pool,
+        PEAK_NONPAGED_POOL = peak_nonpaged_pool,
+        PAGE_FAULTS = memory_counters.PageFaultCount,
+    ))
+}
+
+#[cfg(unix)]
+/// Tries to build a string with human readable data for several of the rusage
+/// fields. Note that we are focusing mainly on data that we believe to be
+/// supplied on Linux (the `rusage` struct has other fields in it but they are
+/// currently unsupported by Linux).
+fn format_rusage_data(_child: Child) -> Option<String> {
+    let rusage: libc::rusage = unsafe {
+        let mut recv = std::mem::zeroed();
+        // -1 is RUSAGE_CHILDREN, which means to get the rusage for all children
+        // (and grandchildren, etc) processes that have respectively terminated
+        // and been waited for.
+        let retval = libc::getrusage(-1, &mut recv);
+        if retval != 0 {
+            return None;
+        }
+        recv
+    };
+    // Mac OS X reports the maxrss in bytes, not kb.
+    let divisor = if env::consts::OS == "macos" { 1024 } else { 1 };
+    let maxrss = (rusage.ru_maxrss + (divisor - 1)) / divisor;
+
+    let mut init_str = format!(
+        "user: {USER_SEC}.{USER_USEC:03} \
+         sys: {SYS_SEC}.{SYS_USEC:03} \
+         max rss (kb): {MAXRSS}",
+        USER_SEC = rusage.ru_utime.tv_sec,
+        USER_USEC = rusage.ru_utime.tv_usec,
+        SYS_SEC = rusage.ru_stime.tv_sec,
+        SYS_USEC = rusage.ru_stime.tv_usec,
+        MAXRSS = maxrss
+    );
+
+    // The remaining rusage stats vary in platform support. So we treat
+    // uniformly zero values in each category as "not worth printing", since it
+    // either means no events of that type occurred, or that the platform
+    // does not support it.
+
+    let minflt = rusage.ru_minflt;
+    let majflt = rusage.ru_majflt;
+    if minflt != 0 || majflt != 0 {
+        init_str.push_str(&format!(" page reclaims: {} page faults: {}", minflt, majflt));
+    }
+
+    let inblock = rusage.ru_inblock;
+    let oublock = rusage.ru_oublock;
+    if inblock != 0 || oublock != 0 {
+        init_str.push_str(&format!(" fs block inputs: {} fs block outputs: {}", inblock, oublock));
+    }
+
+    let nvcsw = rusage.ru_nvcsw;
+    let nivcsw = rusage.ru_nivcsw;
+    if nvcsw != 0 || nivcsw != 0 {
+        init_str.push_str(&format!(
+            " voluntary ctxt switches: {} involuntary ctxt switches: {}",
+            nvcsw, nivcsw
+        ));
+    }
+
+    return Some(init_str);
+}
diff --git a/src/bootstrap/bin/rustdoc.rs b/src/bootstrap/bin/rustdoc.rs
new file mode 100644
index 000000000..87c1d22e7
--- /dev/null
+++ b/src/bootstrap/bin/rustdoc.rs
@@ -0,0 +1,81 @@
+//! Shim which is passed to Cargo as "rustdoc" when running the bootstrap.
+//!
+//! See comments in `src/bootstrap/rustc.rs` for more information.
+
+use std::env;
+use std::ffi::OsString;
+use std::path::PathBuf;
+use std::process::Command;
+
+include!("../dylib_util.rs");
+
+fn main() {
+    let args = env::args_os().skip(1).collect::<Vec<_>>();
+    let rustdoc = env::var_os("RUSTDOC_REAL").expect("RUSTDOC_REAL was not set");
+    let libdir = env::var_os("RUSTDOC_LIBDIR").expect("RUSTDOC_LIBDIR was not set");
+    let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
+
+    // Detect whether or not we're a build script depending on whether --target
+    // is passed (a bit janky...)
+    let target = args.windows(2).find(|w| &*w[0] == "--target").and_then(|w| w[1].to_str());
+
+    use std::str::FromStr;
+
+    let verbose = match env::var("RUSTC_VERBOSE") {
+        Ok(s) => usize::from_str(&s).expect("RUSTC_VERBOSE should be an integer"),
+        Err(_) => 0,
+    };
+
+    let mut dylib_path = dylib_path();
+    dylib_path.insert(0, PathBuf::from(libdir.clone()));
+
+    let mut cmd = Command::new(rustdoc);
+
+    if target.is_some() {
+        // The stage0 compiler has a special sysroot distinct from what we
+        // actually downloaded, so we just always pass the `--sysroot` option,
+        // unless one is already set.
+        if !args.iter().any(|arg| arg == "--sysroot") {
+            cmd.arg("--sysroot").arg(&sysroot);
+        }
+    }
+
+    cmd.args(&args);
+    cmd.env(dylib_path_var(), env::join_paths(&dylib_path).unwrap());
+
+    // Force all crates compiled by this compiler to (a) be unstable and (b)
+    // allow the `rustc_private` feature to link to other unstable crates
+    // also in the sysroot.
+    if env::var_os("RUSTC_FORCE_UNSTABLE").is_some() {
+        cmd.arg("-Z").arg("force-unstable-if-unmarked");
+    }
+    if let Some(linker) = env::var_os("RUSTDOC_LINKER") {
+        let mut arg = OsString::from("-Clinker=");
+        arg.push(&linker);
+        cmd.arg(arg);
+    }
+    if env::var_os("RUSTDOC_FUSE_LD_LLD").is_some() {
+        cmd.arg("-Clink-arg=-fuse-ld=lld");
+        if cfg!(windows) {
+            cmd.arg("-Clink-arg=-Wl,/threads:1");
+        } else {
+            cmd.arg("-Clink-arg=-Wl,--threads=1");
+        }
+    }
+
+    if verbose > 1 {
+        eprintln!(
+            "rustdoc command: {:?}={:?} {:?}",
+            dylib_path_var(),
+            env::join_paths(&dylib_path).unwrap(),
+            cmd,
+        );
+        eprintln!("sysroot: {:?}", sysroot);
+        eprintln!("libdir: {:?}", libdir);
+    }
+
+    std::process::exit(match cmd.status() {
+        Ok(s) => s.code().unwrap_or(1),
+        Err(e) => panic!("\n\nfailed to run {:?}: {}\n\n", cmd, e),
+    })
+}
diff --git a/src/bootstrap/bin/sccache-plus-cl.rs b/src/bootstrap/bin/sccache-plus-cl.rs
new file mode 100644
index 000000000..554c2dd4d
--- /dev/null
+++ b/src/bootstrap/bin/sccache-plus-cl.rs
@@ -0,0 +1,38 @@
+use std::env;
+use std::process::{self, Command};
+
+fn main() {
+    let target = env::var("SCCACHE_TARGET").unwrap();
+    // Locate the actual compiler that we're invoking
+    env::set_var("CC", env::var_os("SCCACHE_CC").unwrap());
+    env::set_var("CXX", env::var_os("SCCACHE_CXX").unwrap());
+    let mut cfg = cc::Build::new();
+    cfg.cargo_metadata(false)
+        .out_dir("/")
+        .target(&target)
+        .host(&target)
+        .opt_level(0)
+        .warnings(false)
+        .debug(false);
+    let compiler = cfg.get_compiler();
+
+    // Invoke sccache with said compiler
+    let sccache_path = env::var_os("SCCACHE_PATH").unwrap();
+    let mut cmd = Command::new(&sccache_path);
+    cmd.arg(compiler.path());
+    for &(ref k, ref v) in compiler.env() {
+        cmd.env(k, v);
+    }
+    for arg in env::args().skip(1) {
+        cmd.arg(arg);
+    }
+
+    if let Ok(s) = env::var("SCCACHE_EXTRA_ARGS") {
+        for s in s.split_whitespace() {
+            cmd.arg(s);
+        }
+    }
+
+    let status = cmd.status().expect("failed to spawn");
+    process::exit(status.code().unwrap_or(2))
+}