1 use libloading::Library;
3 use rustc_codegen_ssa::traits::CodegenBackend;
4 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
5 #[cfg(parallel_compiler)]
6 use rustc_data_structures::jobserver;
7 use rustc_data_structures::sync::Lrc;
8 use rustc_errors::registry::Registry;
9 #[cfg(parallel_compiler)]
10 use rustc_middle::ty::tls;
11 use rustc_parse::validate_attr;
12 #[cfg(parallel_compiler)]
13 use rustc_query_impl::QueryCtxt;
14 use rustc_session as session;
15 use rustc_session::config::CheckCfg;
16 use rustc_session::config::{self, CrateType};
17 use rustc_session::config::{ErrorOutputType, Input, OutputFilenames};
18 use rustc_session::lint::{self, BuiltinLintDiagnostics, LintBuffer};
19 use rustc_session::parse::CrateConfig;
20 use rustc_session::{early_error, filesearch, output, DiagnosticOutput, Session};
21 use rustc_span::edition::Edition;
22 use rustc_span::lev_distance::find_best_match_for_name;
23 use rustc_span::source_map::FileLoader;
24 use rustc_span::symbol::{sym, Symbol};
26 use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
27 use std::lazy::SyncOnceCell;
29 #[cfg(not(parallel_compiler))]
31 use std::path::{Path, PathBuf};
32 use std::sync::atomic::{AtomicBool, Ordering};
36 /// Function pointer type that constructs a new CodegenBackend.
37 pub type MakeBackendFn = fn() -> Box<dyn CodegenBackend>;
39 /// Adds `target_feature = "..."` cfgs for a variety of platform
40 /// specific features (SSE, NEON etc.).
42 /// This is performed by checking whether a set of permitted features
43 /// is available on the target machine, by querying LLVM.
44 pub fn add_configuration(
45 cfg: &mut CrateConfig,
47 codegen_backend: &dyn CodegenBackend,
49 let tf = sym::target_feature;
51 let target_features = codegen_backend.target_features(sess);
52 sess.target_features.extend(target_features.iter().cloned());
54 cfg.extend(target_features.into_iter().map(|feat| (tf, Some(feat))));
56 if sess.crt_static(None) {
57 cfg.insert((tf, Some(sym::crt_dash_static)));
61 pub fn create_session(
62 sopts: config::Options,
63 cfg: FxHashSet<(String, Option<String>)>,
65 diagnostic_output: DiagnosticOutput,
66 file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
67 input_path: Option<PathBuf>,
68 lint_caps: FxHashMap<lint::LintId, lint::Level>,
69 make_codegen_backend: Option<
70 Box<dyn FnOnce(&config::Options) -> Box<dyn CodegenBackend> + Send>,
72 descriptions: Registry,
73 ) -> (Lrc<Session>, Lrc<Box<dyn CodegenBackend>>) {
74 let codegen_backend = if let Some(make_codegen_backend) = make_codegen_backend {
75 make_codegen_backend(&sopts)
79 sopts.debugging_opts.codegen_backend.as_ref().map(|name| &name[..]),
83 // target_override is documented to be called before init(), so this is okay
84 let target_override = codegen_backend.target_override(&sopts);
86 let bundle = match rustc_errors::fluent_bundle(
87 sopts.maybe_sysroot.clone(),
89 sopts.debugging_opts.translate_lang.clone(),
90 sopts.debugging_opts.translate_additional_ftl.as_deref(),
91 sopts.debugging_opts.translate_directionality_markers,
95 early_error(sopts.error_format, &format!("failed to load fluent bundle: {e}"));
99 let mut sess = session::build_session(
110 codegen_backend.init(&sess);
112 let mut cfg = config::build_configuration(&sess, config::to_crate_config(cfg));
113 add_configuration(&mut cfg, &mut sess, &*codegen_backend);
115 let mut check_cfg = config::to_crate_check_config(check_cfg);
116 check_cfg.fill_well_known();
117 check_cfg.fill_actual(&cfg);
119 sess.parse_sess.config = cfg;
120 sess.parse_sess.check_config = check_cfg;
122 (Lrc::new(sess), Lrc::new(codegen_backend))
125 const STACK_SIZE: usize = 8 * 1024 * 1024;
127 fn get_stack_size() -> Option<usize> {
128 // FIXME: Hacks on hacks. If the env is trying to override the stack size
129 // then *don't* set it explicitly.
130 env::var_os("RUST_MIN_STACK").is_none().then_some(STACK_SIZE)
133 /// Like a `thread::Builder::spawn` followed by a `join()`, but avoids the need
134 /// for `'static` bounds.
135 #[cfg(not(parallel_compiler))]
136 fn scoped_thread<F: FnOnce() -> R + Send, R: Send>(cfg: thread::Builder, f: F) -> R {
137 // SAFETY: join() is called immediately, so any closure captures are still
139 match unsafe { cfg.spawn_unchecked(f) }.unwrap().join() {
141 Err(e) => panic::resume_unwind(e),
145 #[cfg(not(parallel_compiler))]
146 pub fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
151 let mut cfg = thread::Builder::new().name("rustc".to_string());
153 if let Some(size) = get_stack_size() {
154 cfg = cfg.stack_size(size);
157 let main_handler = move || rustc_span::create_session_globals_then(edition, f);
159 scoped_thread(cfg, main_handler)
162 /// Creates a new thread and forwards information in thread locals to it.
163 /// The new thread runs the deadlock handler.
164 /// Must only be called when a deadlock is about to happen.
165 #[cfg(parallel_compiler)]
166 unsafe fn handle_deadlock() {
167 let registry = rustc_rayon_core::Registry::current();
169 let context = tls::get_tlv();
170 assert!(context != 0);
171 rustc_data_structures::sync::assert_sync::<tls::ImplicitCtxt<'_, '_>>();
172 let icx: &tls::ImplicitCtxt<'_, '_> = &*(context as *const tls::ImplicitCtxt<'_, '_>);
174 let session_globals = rustc_span::with_session_globals(|sg| sg as *const _);
175 let session_globals = &*session_globals;
176 thread::spawn(move || {
177 tls::enter_context(icx, |_| {
178 rustc_span::set_session_globals_then(session_globals, || {
179 tls::with(|tcx| QueryCtxt::from_tcx(tcx).deadlock(®istry))
185 #[cfg(parallel_compiler)]
186 pub fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
191 let mut config = rayon::ThreadPoolBuilder::new()
192 .thread_name(|_| "rustc".to_string())
193 .acquire_thread_handler(jobserver::acquire_thread)
194 .release_thread_handler(jobserver::release_thread)
195 .num_threads(threads)
196 .deadlock_handler(|| unsafe { handle_deadlock() });
198 if let Some(size) = get_stack_size() {
199 config = config.stack_size(size);
202 let with_pool = move |pool: &rayon::ThreadPool| pool.install(f);
204 rustc_span::create_session_globals_then(edition, || {
205 rustc_span::with_session_globals(|session_globals| {
206 // The main handler runs for each Rayon worker thread and sets up
207 // the thread local rustc uses. `session_globals` is captured and set
208 // on the new threads.
209 let main_handler = move |thread: rayon::ThreadBuilder| {
210 rustc_span::set_session_globals_then(session_globals, || thread.run())
213 config.build_scoped(main_handler, with_pool).unwrap()
218 fn load_backend_from_dylib(path: &Path) -> MakeBackendFn {
219 let lib = unsafe { Library::new(path) }.unwrap_or_else(|err| {
220 let err = format!("couldn't load codegen backend {:?}: {}", path, err);
221 early_error(ErrorOutputType::default(), &err);
224 let backend_sym = unsafe { lib.get::<MakeBackendFn>(b"__rustc_codegen_backend") }
225 .unwrap_or_else(|e| {
226 let err = format!("couldn't load codegen backend: {}", e);
227 early_error(ErrorOutputType::default(), &err);
230 // Intentionally leak the dynamic library. We can't ever unload it
231 // since the library can make things that will live arbitrarily long.
232 let backend_sym = unsafe { backend_sym.into_raw() };
238 /// Get the codegen backend based on the name and specified sysroot.
240 /// A name of `None` indicates that the default backend should be used.
241 pub fn get_codegen_backend(
242 maybe_sysroot: &Option<PathBuf>,
243 backend_name: Option<&str>,
244 ) -> Box<dyn CodegenBackend> {
245 static LOAD: SyncOnceCell<unsafe fn() -> Box<dyn CodegenBackend>> = SyncOnceCell::new();
247 let load = LOAD.get_or_init(|| {
248 let default_codegen_backend = option_env!("CFG_DEFAULT_CODEGEN_BACKEND").unwrap_or("llvm");
250 match backend_name.unwrap_or(default_codegen_backend) {
251 filename if filename.contains('.') => load_backend_from_dylib(filename.as_ref()),
252 #[cfg(feature = "llvm")]
253 "llvm" => rustc_codegen_llvm::LlvmCodegenBackend::new,
254 backend_name => get_codegen_sysroot(maybe_sysroot, backend_name),
258 // SAFETY: In case of a builtin codegen backend this is safe. In case of an external codegen
259 // backend we hope that the backend links against the same rustc_driver version. If this is not
260 // the case, we get UB.
264 // This is used for rustdoc, but it uses similar machinery to codegen backend
265 // loading, so we leave the code here. It is potentially useful for other tools
266 // that want to invoke the rustc binary while linking to rustc as well.
267 pub fn rustc_path<'a>() -> Option<&'a Path> {
268 static RUSTC_PATH: SyncOnceCell<Option<PathBuf>> = SyncOnceCell::new();
270 const BIN_PATH: &str = env!("RUSTC_INSTALL_BINDIR");
272 RUSTC_PATH.get_or_init(|| get_rustc_path_inner(BIN_PATH)).as_ref().map(|v| &**v)
275 fn get_rustc_path_inner(bin_path: &str) -> Option<PathBuf> {
276 sysroot_candidates().iter().find_map(|sysroot| {
277 let candidate = sysroot.join(bin_path).join(if cfg!(target_os = "windows") {
282 candidate.exists().then_some(candidate)
286 fn sysroot_candidates() -> Vec<PathBuf> {
287 let target = session::config::host_triple();
288 let mut sysroot_candidates = vec![filesearch::get_or_default_sysroot()];
289 let path = current_dll_path().and_then(|s| s.canonicalize().ok());
290 if let Some(dll) = path {
291 // use `parent` twice to chop off the file name and then also the
292 // directory containing the dll which should be either `lib` or `bin`.
293 if let Some(path) = dll.parent().and_then(|p| p.parent()) {
294 // The original `path` pointed at the `rustc_driver` crate's dll.
295 // Now that dll should only be in one of two locations. The first is
296 // in the compiler's libdir, for example `$sysroot/lib/*.dll`. The
297 // other is the target's libdir, for example
298 // `$sysroot/lib/rustlib/$target/lib/*.dll`.
300 // We don't know which, so let's assume that if our `path` above
301 // ends in `$target` we *could* be in the target libdir, and always
302 // assume that we may be in the main libdir.
303 sysroot_candidates.push(path.to_owned());
305 if path.ends_with(target) {
306 sysroot_candidates.extend(
307 path.parent() // chop off `$target`
308 .and_then(|p| p.parent()) // chop off `rustlib`
309 .and_then(|p| p.parent()) // chop off `lib`
310 .map(|s| s.to_owned()),
316 return sysroot_candidates;
319 fn current_dll_path() -> Option<PathBuf> {
320 use std::ffi::{CStr, OsStr};
321 use std::os::unix::prelude::*;
324 let addr = current_dll_path as usize as *mut _;
325 let mut info = mem::zeroed();
326 if libc::dladdr(addr, &mut info) == 0 {
327 info!("dladdr failed");
330 if info.dli_fname.is_null() {
331 info!("dladdr returned null pointer");
334 let bytes = CStr::from_ptr(info.dli_fname).to_bytes();
335 let os = OsStr::from_bytes(bytes);
336 Some(PathBuf::from(os))
341 fn current_dll_path() -> Option<PathBuf> {
342 use std::ffi::OsString;
344 use std::os::windows::prelude::*;
347 use winapi::um::libloaderapi::{
348 GetModuleFileNameW, GetModuleHandleExW, GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
352 let mut module = ptr::null_mut();
353 let r = GetModuleHandleExW(
354 GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
355 current_dll_path as usize as *mut _,
359 info!("GetModuleHandleExW failed: {}", io::Error::last_os_error());
362 let mut space = Vec::with_capacity(1024);
363 let r = GetModuleFileNameW(module, space.as_mut_ptr(), space.capacity() as u32);
365 info!("GetModuleFileNameW failed: {}", io::Error::last_os_error());
369 if r >= space.capacity() {
370 info!("our buffer was too small? {}", io::Error::last_os_error());
374 let os = OsString::from_wide(&space);
375 Some(PathBuf::from(os))
380 fn get_codegen_sysroot(maybe_sysroot: &Option<PathBuf>, backend_name: &str) -> MakeBackendFn {
381 // For now we only allow this function to be called once as it'll dlopen a
382 // few things, which seems to work best if we only do that once. In
383 // general this assertion never trips due to the once guard in `get_codegen_backend`,
384 // but there's a few manual calls to this function in this file we protect
386 static LOADED: AtomicBool = AtomicBool::new(false);
388 !LOADED.fetch_or(true, Ordering::SeqCst),
389 "cannot load the default codegen backend twice"
392 let target = session::config::host_triple();
393 let sysroot_candidates = sysroot_candidates();
395 let sysroot = maybe_sysroot
397 .chain(sysroot_candidates.iter())
399 filesearch::make_target_lib_path(sysroot, target).with_file_name("codegen-backends")
402 info!("codegen backend candidate: {}", f.display());
405 let sysroot = sysroot.unwrap_or_else(|| {
406 let candidates = sysroot_candidates
408 .map(|p| p.display().to_string())
412 "failed to find a `codegen-backends` folder \
413 in the sysroot candidates:\n* {}",
416 early_error(ErrorOutputType::default(), &err);
418 info!("probing {} for a codegen backend", sysroot.display());
420 let d = sysroot.read_dir().unwrap_or_else(|e| {
422 "failed to load default codegen backend, couldn't \
427 early_error(ErrorOutputType::default(), &err);
430 let mut file: Option<PathBuf> = None;
432 let expected_names = &[
433 format!("rustc_codegen_{}-{}", backend_name, release_str().expect("CFG_RELEASE")),
434 format!("rustc_codegen_{}", backend_name),
436 for entry in d.filter_map(|e| e.ok()) {
437 let path = entry.path();
438 let Some(filename) = path.file_name().and_then(|s| s.to_str()) else { continue };
439 if !(filename.starts_with(DLL_PREFIX) && filename.ends_with(DLL_SUFFIX)) {
442 let name = &filename[DLL_PREFIX.len()..filename.len() - DLL_SUFFIX.len()];
443 if !expected_names.iter().any(|expected| expected == name) {
446 if let Some(ref prev) = file {
448 "duplicate codegen backends found\n\
455 early_error(ErrorOutputType::default(), &err);
457 file = Some(path.clone());
461 Some(ref s) => load_backend_from_dylib(s),
463 let err = format!("unsupported builtin codegen backend `{}`", backend_name);
464 early_error(ErrorOutputType::default(), &err);
469 pub(crate) fn check_attr_crate_type(
471 attrs: &[ast::Attribute],
472 lint_buffer: &mut LintBuffer,
474 // Unconditionally collect crate types from attributes to make them used
475 for a in attrs.iter() {
476 if a.has_name(sym::crate_type) {
477 if let Some(n) = a.value_str() {
478 if categorize_crate_type(n).is_some() {
482 if let ast::MetaItemKind::NameValue(spanned) = a.meta_kind().unwrap() {
483 let span = spanned.span;
484 let lev_candidate = find_best_match_for_name(
485 &CRATE_TYPES.iter().map(|(k, _)| *k).collect::<Vec<_>>(),
489 if let Some(candidate) = lev_candidate {
490 lint_buffer.buffer_lint_with_diagnostic(
491 lint::builtin::UNKNOWN_CRATE_TYPES,
494 "invalid `crate_type` value",
495 BuiltinLintDiagnostics::UnknownCrateTypes(
497 "did you mean".to_string(),
498 format!("\"{}\"", candidate),
502 lint_buffer.buffer_lint(
503 lint::builtin::UNKNOWN_CRATE_TYPES,
506 "invalid `crate_type` value",
511 // This is here mainly to check for using a macro, such as
512 // #![crate_type = foo!()]. That is not supported since the
513 // crate type needs to be known very early in compilation long
514 // before expansion. Otherwise, validation would normally be
515 // caught in AstValidator (via `check_builtin_attribute`), but
516 // by the time that runs the macro is expanded, and it doesn't
518 validate_attr::emit_fatal_malformed_builtin_attribute(
528 const CRATE_TYPES: &[(Symbol, CrateType)] = &[
529 (sym::rlib, CrateType::Rlib),
530 (sym::dylib, CrateType::Dylib),
531 (sym::cdylib, CrateType::Cdylib),
532 (sym::lib, config::default_lib_output()),
533 (sym::staticlib, CrateType::Staticlib),
534 (sym::proc_dash_macro, CrateType::ProcMacro),
535 (sym::bin, CrateType::Executable),
538 fn categorize_crate_type(s: Symbol) -> Option<CrateType> {
539 Some(CRATE_TYPES.iter().find(|(key, _)| *key == s)?.1)
542 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<CrateType> {
543 // Unconditionally collect crate types from attributes to make them used
544 let attr_types: Vec<CrateType> = attrs
547 if a.has_name(sym::crate_type) {
548 match a.value_str() {
549 Some(s) => categorize_crate_type(s),
558 // If we're generating a test executable, then ignore all other output
559 // styles at all other locations
560 if session.opts.test {
561 return vec![CrateType::Executable];
564 // Only check command line flags if present. If no types are specified by
565 // command line, then reuse the empty `base` Vec to hold the types that
566 // will be found in crate attributes.
567 let mut base = session.opts.crate_types.clone();
569 base.extend(attr_types);
571 base.push(output::default_output_for_target(session));
578 base.retain(|crate_type| {
579 let res = !output::invalid_output_for_target(session, *crate_type);
582 session.warn(&format!(
583 "dropping unsupported crate type `{}` for target `{}`",
584 *crate_type, session.opts.target_triple
594 pub fn build_output_filenames(
596 odir: &Option<PathBuf>,
597 ofile: &Option<PathBuf>,
598 temps_dir: &Option<PathBuf>,
599 attrs: &[ast::Attribute],
601 ) -> OutputFilenames {
604 // "-" as input file will cause the parser to read from stdin so we
605 // have to make up a name
606 // We want to toss everything after the final '.'
607 let dirpath = (*odir).as_ref().cloned().unwrap_or_default();
609 // If a crate name is present, we use it as the link name
614 .or_else(|| rustc_attr::find_crate_name(sess, attrs).map(|n| n.to_string()))
615 .unwrap_or_else(|| input.filestem().to_owned());
617 OutputFilenames::new(
622 sess.opts.cg.extra_filename.clone(),
623 sess.opts.output_types.clone(),
627 Some(ref out_file) => {
628 let unnamed_output_types =
629 sess.opts.output_types.values().filter(|a| a.is_none()).count();
630 let ofile = if unnamed_output_types > 1 {
632 "due to multiple output types requested, the explicitly specified \
633 output file name will be adapted for each output type",
637 if !sess.opts.cg.extra_filename.is_empty() {
638 sess.warn("ignoring -C extra-filename flag due to -o flag");
640 Some(out_file.clone())
643 sess.warn("ignoring --out-dir flag due to -o flag");
646 OutputFilenames::new(
647 out_file.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),
648 out_file.file_stem().unwrap_or_default().to_str().unwrap().to_string(),
651 sess.opts.cg.extra_filename.clone(),
652 sess.opts.output_types.clone(),
658 #[cfg(not(target_os = "linux"))]
659 pub fn non_durable_rename(src: &Path, dst: &Path) -> std::io::Result<()> {
660 std::fs::rename(src, dst)
663 /// This function attempts to bypass the auto_da_alloc heuristic implemented by some filesystems
664 /// such as btrfs and ext4. When renaming over a file that already exists then they will "helpfully"
665 /// write back the source file before committing the rename in case a developer forgot some of
666 /// the fsyncs in the open/write/fsync(file)/rename/fsync(dir) dance for atomic file updates.
668 /// To avoid triggering this heuristic we delete the destination first, if it exists.
669 /// The cost of an extra syscall is much lower than getting descheduled for the sync IO.
670 #[cfg(target_os = "linux")]
671 pub fn non_durable_rename(src: &Path, dst: &Path) -> std::io::Result<()> {
672 let _ = std::fs::remove_file(dst);
673 std::fs::rename(src, dst)
676 /// Returns a version string such as "1.46.0 (04488afe3 2020-08-24)"
677 pub fn version_str() -> Option<&'static str> {
678 option_env!("CFG_VERSION")
681 /// Returns a version string such as "0.12.0-dev".
682 pub fn release_str() -> Option<&'static str> {
683 option_env!("CFG_RELEASE")
686 /// Returns the full SHA1 hash of HEAD of the Git repo from which rustc was built.
687 pub fn commit_hash_str() -> Option<&'static str> {
688 option_env!("CFG_VER_HASH")
691 /// Returns the "commit date" of HEAD of the Git repo from which rustc was built as a static string.
692 pub fn commit_date_str() -> Option<&'static str> {
693 option_env!("CFG_VER_DATE")