bootstrap/utils/
helpers.rs

1//! Various utility functions used throughout bootstrap.
2//!
3//! Simple things like testing the various filesystem operations here and there,
4//! not a lot of interesting happenings here unfortunately.
5
6use std::ffi::OsStr;
7use std::path::{Path, PathBuf};
8use std::sync::OnceLock;
9use std::thread::panicking;
10use std::time::{Instant, SystemTime, UNIX_EPOCH};
11use std::{env, fs, io, panic, str};
12
13use object::read::archive::ArchiveFile;
14
15use crate::LldMode;
16use crate::core::builder::Builder;
17use crate::core::config::{Config, TargetSelection};
18use crate::utils::exec::{BootstrapCommand, command};
19pub use crate::utils::shared_helpers::{dylib_path, dylib_path_var};
20
21#[cfg(test)]
22mod tests;
23
24/// A wrapper around `std::panic::Location` used to track the location of panics
25/// triggered by `t` macro usage.
26pub struct PanicTracker<'a>(pub &'a panic::Location<'a>);
27
28impl Drop for PanicTracker<'_> {
29    fn drop(&mut self) {
30        if panicking() {
31            eprintln!(
32                "Panic was initiated from {}:{}:{}",
33                self.0.file(),
34                self.0.line(),
35                self.0.column()
36            );
37        }
38    }
39}
40
41/// A helper macro to `unwrap` a result except also print out details like:
42///
43/// * The file/line of the panic
44/// * The expression that failed
45/// * The error itself
46///
47/// This is currently used judiciously throughout the build system rather than
48/// using a `Result` with `try!`, but this may change one day...
49#[macro_export]
50macro_rules! t {
51    ($e:expr) => {{
52        let _panic_guard = $crate::PanicTracker(std::panic::Location::caller());
53        match $e {
54            Ok(e) => e,
55            Err(e) => panic!("{} failed with {}", stringify!($e), e),
56        }
57    }};
58    // it can show extra info in the second parameter
59    ($e:expr, $extra:expr) => {{
60        let _panic_guard = $crate::PanicTracker(std::panic::Location::caller());
61        match $e {
62            Ok(e) => e,
63            Err(e) => panic!("{} failed with {} ({:?})", stringify!($e), e, $extra),
64        }
65    }};
66}
67
68pub use t;
69pub fn exe(name: &str, target: TargetSelection) -> String {
70    crate::utils::shared_helpers::exe(name, &target.triple)
71}
72
73/// Returns the path to the split debug info for the specified file if it exists.
74pub fn split_debuginfo(name: impl Into<PathBuf>) -> Option<PathBuf> {
75    // FIXME: only msvc is currently supported
76
77    let path = name.into();
78    let pdb = path.with_extension("pdb");
79    if pdb.exists() {
80        return Some(pdb);
81    }
82
83    // pdbs get named with '-' replaced by '_'
84    let file_name = pdb.file_name()?.to_str()?.replace("-", "_");
85
86    let pdb: PathBuf = [path.parent()?, Path::new(&file_name)].into_iter().collect();
87    pdb.exists().then_some(pdb)
88}
89
90/// Returns `true` if the file name given looks like a dynamic library.
91pub fn is_dylib(path: &Path) -> bool {
92    path.extension().and_then(|ext| ext.to_str()).is_some_and(|ext| {
93        ext == "dylib" || ext == "so" || ext == "dll" || (ext == "a" && is_aix_shared_archive(path))
94    })
95}
96
97/// Return the path to the containing submodule if available.
98pub fn submodule_path_of(builder: &Builder<'_>, path: &str) -> Option<String> {
99    let submodule_paths = builder.submodule_paths();
100    submodule_paths.iter().find_map(|submodule_path| {
101        if path.starts_with(submodule_path) { Some(submodule_path.to_string()) } else { None }
102    })
103}
104
105fn is_aix_shared_archive(path: &Path) -> bool {
106    let file = match fs::File::open(path) {
107        Ok(file) => file,
108        Err(_) => return false,
109    };
110    let reader = object::ReadCache::new(file);
111    let archive = match ArchiveFile::parse(&reader) {
112        Ok(result) => result,
113        Err(_) => return false,
114    };
115
116    archive
117        .members()
118        .filter_map(Result::ok)
119        .any(|entry| String::from_utf8_lossy(entry.name()).contains(".so"))
120}
121
122/// Returns `true` if the file name given looks like a debug info file
123pub fn is_debug_info(name: &str) -> bool {
124    // FIXME: consider split debug info on other platforms (e.g., Linux, macOS)
125    name.ends_with(".pdb")
126}
127
128/// Returns the corresponding relative library directory that the compiler's
129/// dylibs will be found in.
130pub fn libdir(target: TargetSelection) -> &'static str {
131    if target.is_windows() || target.contains("cygwin") { "bin" } else { "lib" }
132}
133
134/// Adds a list of lookup paths to `cmd`'s dynamic library lookup path.
135/// If the dylib_path_var is already set for this cmd, the old value will be overwritten!
136pub fn add_dylib_path(path: Vec<PathBuf>, cmd: &mut BootstrapCommand) {
137    let mut list = dylib_path();
138    for path in path {
139        list.insert(0, path);
140    }
141    cmd.env(dylib_path_var(), t!(env::join_paths(list)));
142}
143
144pub struct TimeIt(bool, Instant);
145
146/// Returns an RAII structure that prints out how long it took to drop.
147pub fn timeit(builder: &Builder<'_>) -> TimeIt {
148    TimeIt(builder.config.dry_run(), Instant::now())
149}
150
151impl Drop for TimeIt {
152    fn drop(&mut self) {
153        let time = self.1.elapsed();
154        if !self.0 {
155            println!("\tfinished in {}.{:03} seconds", time.as_secs(), time.subsec_millis());
156        }
157    }
158}
159
160/// Symlinks two directories, using junctions on Windows and normal symlinks on
161/// Unix.
162pub fn symlink_dir(config: &Config, original: &Path, link: &Path) -> io::Result<()> {
163    if config.dry_run() {
164        return Ok(());
165    }
166    let _ = fs::remove_dir_all(link);
167    return symlink_dir_inner(original, link);
168
169    #[cfg(not(windows))]
170    fn symlink_dir_inner(original: &Path, link: &Path) -> io::Result<()> {
171        use std::os::unix::fs;
172        fs::symlink(original, link)
173    }
174
175    #[cfg(windows)]
176    fn symlink_dir_inner(target: &Path, junction: &Path) -> io::Result<()> {
177        junction::create(target, junction)
178    }
179}
180
181/// Return the host target on which we are currently running.
182pub fn get_host_target() -> TargetSelection {
183    TargetSelection::from_user(env!("BUILD_TRIPLE"))
184}
185
186/// Rename a file if from and to are in the same filesystem or
187/// copy and remove the file otherwise
188pub fn move_file<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::Result<()> {
189    match fs::rename(&from, &to) {
190        Err(e) if e.kind() == io::ErrorKind::CrossesDevices => {
191            std::fs::copy(&from, &to)?;
192            std::fs::remove_file(&from)
193        }
194        r => r,
195    }
196}
197
198pub fn forcing_clang_based_tests() -> bool {
199    if let Some(var) = env::var_os("RUSTBUILD_FORCE_CLANG_BASED_TESTS") {
200        match &var.to_string_lossy().to_lowercase()[..] {
201            "1" | "yes" | "on" => true,
202            "0" | "no" | "off" => false,
203            other => {
204                // Let's make sure typos don't go unnoticed
205                panic!(
206                    "Unrecognized option '{other}' set in \
207                        RUSTBUILD_FORCE_CLANG_BASED_TESTS"
208                )
209            }
210        }
211    } else {
212        false
213    }
214}
215
216pub fn use_host_linker(target: TargetSelection) -> bool {
217    // FIXME: this information should be gotten by checking the linker flavor
218    // of the rustc target
219    !(target.contains("emscripten")
220        || target.contains("wasm32")
221        || target.contains("nvptx")
222        || target.contains("fortanix")
223        || target.contains("fuchsia")
224        || target.contains("bpf")
225        || target.contains("switch"))
226}
227
228pub fn target_supports_cranelift_backend(target: TargetSelection) -> bool {
229    if target.contains("linux") {
230        target.contains("x86_64")
231            || target.contains("aarch64")
232            || target.contains("s390x")
233            || target.contains("riscv64gc")
234    } else if target.contains("darwin") {
235        target.contains("x86_64") || target.contains("aarch64")
236    } else if target.is_windows() {
237        target.contains("x86_64")
238    } else {
239        false
240    }
241}
242
243pub fn is_valid_test_suite_arg<'a, P: AsRef<Path>>(
244    path: &'a Path,
245    suite_path: P,
246    builder: &Builder<'_>,
247) -> Option<&'a str> {
248    let suite_path = suite_path.as_ref();
249    let path = match path.strip_prefix(".") {
250        Ok(p) => p,
251        Err(_) => path,
252    };
253    if !path.starts_with(suite_path) {
254        return None;
255    }
256    let abs_path = builder.src.join(path);
257    let exists = abs_path.is_dir() || abs_path.is_file();
258    if !exists {
259        panic!(
260            "Invalid test suite filter \"{}\": file or directory does not exist",
261            abs_path.display()
262        );
263    }
264    // Since test suite paths are themselves directories, if we don't
265    // specify a directory or file, we'll get an empty string here
266    // (the result of the test suite directory without its suite prefix).
267    // Therefore, we need to filter these out, as only the first --test-args
268    // flag is respected, so providing an empty --test-args conflicts with
269    // any following it.
270    match path.strip_prefix(suite_path).ok().and_then(|p| p.to_str()) {
271        Some(s) if !s.is_empty() => Some(s),
272        _ => None,
273    }
274}
275
276pub fn make(host: &str) -> PathBuf {
277    if host.contains("dragonfly")
278        || host.contains("freebsd")
279        || host.contains("netbsd")
280        || host.contains("openbsd")
281    {
282        PathBuf::from("gmake")
283    } else {
284        PathBuf::from("make")
285    }
286}
287
288/// Returns the last-modified time for `path`, or zero if it doesn't exist.
289pub fn mtime(path: &Path) -> SystemTime {
290    fs::metadata(path).and_then(|f| f.modified()).unwrap_or(UNIX_EPOCH)
291}
292
293/// Returns `true` if `dst` is up to date given that the file or files in `src`
294/// are used to generate it.
295///
296/// Uses last-modified time checks to verify this.
297pub fn up_to_date(src: &Path, dst: &Path) -> bool {
298    if !dst.exists() {
299        return false;
300    }
301    let threshold = mtime(dst);
302    let meta = match fs::metadata(src) {
303        Ok(meta) => meta,
304        Err(e) => panic!("source {src:?} failed to get metadata: {e}"),
305    };
306    if meta.is_dir() {
307        dir_up_to_date(src, threshold)
308    } else {
309        meta.modified().unwrap_or(UNIX_EPOCH) <= threshold
310    }
311}
312
313/// Returns the filename without the hash prefix added by the cc crate.
314///
315/// Since v1.0.78 of the cc crate, object files are prefixed with a 16-character hash
316/// to avoid filename collisions.
317pub fn unhashed_basename(obj: &Path) -> &str {
318    let basename = obj.file_stem().unwrap().to_str().expect("UTF-8 file name");
319    basename.split_once('-').unwrap().1
320}
321
322fn dir_up_to_date(src: &Path, threshold: SystemTime) -> bool {
323    t!(fs::read_dir(src)).map(|e| t!(e)).all(|e| {
324        let meta = t!(e.metadata());
325        if meta.is_dir() {
326            dir_up_to_date(&e.path(), threshold)
327        } else {
328            meta.modified().unwrap_or(UNIX_EPOCH) < threshold
329        }
330    })
331}
332
333/// Adapted from <https://github.com/llvm/llvm-project/blob/782e91224601e461c019e0a4573bbccc6094fbcd/llvm/cmake/modules/HandleLLVMOptions.cmake#L1058-L1079>
334///
335/// When `clang-cl` is used with instrumentation, we need to add clang's runtime library resource
336/// directory to the linker flags, otherwise there will be linker errors about the profiler runtime
337/// missing. This function returns the path to that directory.
338pub fn get_clang_cl_resource_dir(builder: &Builder<'_>, clang_cl_path: &str) -> PathBuf {
339    // Similar to how LLVM does it, to find clang's library runtime directory:
340    // - we ask `clang-cl` to locate the `clang_rt.builtins` lib.
341    let mut builtins_locator = command(clang_cl_path);
342    builtins_locator.args(["/clang:-print-libgcc-file-name", "/clang:--rtlib=compiler-rt"]);
343
344    let clang_rt_builtins = builtins_locator.run_capture_stdout(builder).stdout();
345    let clang_rt_builtins = Path::new(clang_rt_builtins.trim());
346    assert!(
347        clang_rt_builtins.exists(),
348        "`clang-cl` must correctly locate the library runtime directory"
349    );
350
351    // - the profiler runtime will be located in the same directory as the builtins lib, like
352    // `$LLVM_DISTRO_ROOT/lib/clang/$LLVM_VERSION/lib/windows`.
353    let clang_rt_dir = clang_rt_builtins.parent().expect("The clang lib folder should exist");
354    clang_rt_dir.to_path_buf()
355}
356
357/// Returns a flag that configures LLD to use only a single thread.
358/// If we use an external LLD, we need to find out which version is it to know which flag should we
359/// pass to it (LLD older than version 10 had a different flag).
360fn lld_flag_no_threads(builder: &Builder<'_>, lld_mode: LldMode, is_windows: bool) -> &'static str {
361    static LLD_NO_THREADS: OnceLock<(&'static str, &'static str)> = OnceLock::new();
362
363    let new_flags = ("/threads:1", "--threads=1");
364    let old_flags = ("/no-threads", "--no-threads");
365
366    let (windows_flag, other_flag) = LLD_NO_THREADS.get_or_init(|| {
367        let newer_version = match lld_mode {
368            LldMode::External => {
369                let mut cmd = command("lld");
370                cmd.arg("-flavor").arg("ld").arg("--version");
371                let out = cmd.run_capture_stdout(builder).stdout();
372                match (out.find(char::is_numeric), out.find('.')) {
373                    (Some(b), Some(e)) => out.as_str()[b..e].parse::<i32>().ok().unwrap_or(14) > 10,
374                    _ => true,
375                }
376            }
377            _ => true,
378        };
379        if newer_version { new_flags } else { old_flags }
380    });
381    if is_windows { windows_flag } else { other_flag }
382}
383
384pub fn dir_is_empty(dir: &Path) -> bool {
385    t!(std::fs::read_dir(dir), dir).next().is_none()
386}
387
388/// Extract the beta revision from the full version string.
389///
390/// The full version string looks like "a.b.c-beta.y". And we need to extract
391/// the "y" part from the string.
392pub fn extract_beta_rev(version: &str) -> Option<String> {
393    let parts = version.splitn(2, "-beta.").collect::<Vec<_>>();
394    parts.get(1).and_then(|s| s.find(' ').map(|p| s[..p].to_string()))
395}
396
397pub enum LldThreads {
398    Yes,
399    No,
400}
401
402/// Returns the linker arguments for rustc/rustdoc for the given builder and target.
403pub fn linker_args(
404    builder: &Builder<'_>,
405    target: TargetSelection,
406    lld_threads: LldThreads,
407) -> Vec<String> {
408    let mut args = linker_flags(builder, target, lld_threads);
409
410    if let Some(linker) = builder.linker(target) {
411        args.push(format!("-Clinker={}", linker.display()));
412    }
413
414    args
415}
416
417/// Returns the linker arguments for rustc/rustdoc for the given builder and target, without the
418/// -Clinker flag.
419pub fn linker_flags(
420    builder: &Builder<'_>,
421    target: TargetSelection,
422    lld_threads: LldThreads,
423) -> Vec<String> {
424    let mut args = vec![];
425    if !builder.is_lld_direct_linker(target) && builder.config.lld_mode.is_used() {
426        match builder.config.lld_mode {
427            LldMode::External => {
428                args.push("-Zlinker-features=+lld".to_string());
429                // FIXME(kobzol): remove this flag once MCP510 gets stabilized
430                args.push("-Zunstable-options".to_string());
431            }
432            LldMode::SelfContained => {
433                args.push("-Zlinker-features=+lld".to_string());
434                args.push("-Clink-self-contained=+linker".to_string());
435                // FIXME(kobzol): remove this flag once MCP510 gets stabilized
436                args.push("-Zunstable-options".to_string());
437            }
438            LldMode::Unused => unreachable!(),
439        };
440
441        if matches!(lld_threads, LldThreads::No) {
442            args.push(format!(
443                "-Clink-arg=-Wl,{}",
444                lld_flag_no_threads(builder, builder.config.lld_mode, target.is_windows())
445            ));
446        }
447    }
448    args
449}
450
451pub fn add_rustdoc_cargo_linker_args(
452    cmd: &mut BootstrapCommand,
453    builder: &Builder<'_>,
454    target: TargetSelection,
455    lld_threads: LldThreads,
456) {
457    let args = linker_args(builder, target, lld_threads);
458    let mut flags = cmd
459        .get_envs()
460        .find_map(|(k, v)| if k == OsStr::new("RUSTDOCFLAGS") { v } else { None })
461        .unwrap_or_default()
462        .to_os_string();
463    for arg in args {
464        if !flags.is_empty() {
465            flags.push(" ");
466        }
467        flags.push(arg);
468    }
469    if !flags.is_empty() {
470        cmd.env("RUSTDOCFLAGS", flags);
471    }
472}
473
474/// Converts `T` into a hexadecimal `String`.
475pub fn hex_encode<T>(input: T) -> String
476where
477    T: AsRef<[u8]>,
478{
479    use std::fmt::Write;
480
481    input.as_ref().iter().fold(String::with_capacity(input.as_ref().len() * 2), |mut acc, &byte| {
482        write!(&mut acc, "{byte:02x}").expect("Failed to write byte to the hex String.");
483        acc
484    })
485}
486
487/// Create a `--check-cfg` argument invocation for a given name
488/// and it's values.
489pub fn check_cfg_arg(name: &str, values: Option<&[&str]>) -> String {
490    // Creating a string of the values by concatenating each value:
491    // ',values("tvos","watchos")' or '' (nothing) when there are no values.
492    let next = match values {
493        Some(values) => {
494            let mut tmp = values.iter().flat_map(|val| [",", "\"", val, "\""]).collect::<String>();
495
496            tmp.insert_str(1, "values(");
497            tmp.push(')');
498            tmp
499        }
500        None => "".to_string(),
501    };
502    format!("--check-cfg=cfg({name}{next})")
503}
504
505/// Prepares `BootstrapCommand` that runs git inside the source directory if given.
506///
507/// Whenever a git invocation is needed, this function should be preferred over
508/// manually building a git `BootstrapCommand`. This approach allows us to manage
509/// bootstrap-specific needs/hacks from a single source, rather than applying them on next to every
510/// git command creation, which is painful to ensure that the required change is applied
511/// on each one of them correctly.
512#[track_caller]
513pub fn git(source_dir: Option<&Path>) -> BootstrapCommand {
514    let mut git = command("git");
515
516    if let Some(source_dir) = source_dir {
517        git.current_dir(source_dir);
518        // If we are running inside git (e.g. via a hook), `GIT_DIR` is set and takes precedence
519        // over the current dir. Un-set it to make the current dir matter.
520        git.env_remove("GIT_DIR");
521        // Also un-set some other variables, to be on the safe side (based on cargo's
522        // `fetch_with_cli`). In particular un-setting `GIT_INDEX_FILE` is required to fix some odd
523        // misbehavior.
524        git.env_remove("GIT_WORK_TREE")
525            .env_remove("GIT_INDEX_FILE")
526            .env_remove("GIT_OBJECT_DIRECTORY")
527            .env_remove("GIT_ALTERNATE_OBJECT_DIRECTORIES");
528    }
529
530    git
531}
532
533/// Sets the file times for a given file at `path`.
534pub fn set_file_times<P: AsRef<Path>>(path: P, times: fs::FileTimes) -> io::Result<()> {
535    // Windows requires file to be writable to modify file times. But on Linux CI the file does not
536    // need to be writable to modify file times and might be read-only.
537    let f = if cfg!(windows) {
538        fs::File::options().write(true).open(path)?
539    } else {
540        fs::File::open(path)?
541    };
542    f.set_times(times)
543}
bootstrap/utils/helpers.rs

bootstrap/utils/
helpers.rs
