2 use libloading::Library;
4 use rustc_codegen_ssa::traits::CodegenBackend;
5 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
6 #[cfg(parallel_compiler)]
7 use rustc_data_structures::jobserver;
8 use rustc_data_structures::sync::Lrc;
9 use rustc_errors::registry::Registry;
10 #[cfg(parallel_compiler)]
11 use rustc_middle::ty::tls;
12 use rustc_parse::validate_attr;
13 #[cfg(parallel_compiler)]
14 use rustc_query_impl::{QueryContext, QueryCtxt};
15 use rustc_session as session;
16 use rustc_session::config::CheckCfg;
17 use rustc_session::config::{self, CrateType};
18 use rustc_session::config::{ErrorOutputType, Input, OutputFilenames};
19 use rustc_session::lint::{self, BuiltinLintDiagnostics, LintBuffer};
20 use rustc_session::parse::CrateConfig;
21 use rustc_session::{early_error, filesearch, output, Session};
22 use rustc_span::edition::Edition;
23 use rustc_span::lev_distance::find_best_match_for_name;
24 use rustc_span::source_map::FileLoader;
25 use rustc_span::symbol::{sym, Symbol};
27 use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
29 #[cfg(not(parallel_compiler))]
31 use std::path::{Path, PathBuf};
32 use std::sync::atomic::{AtomicBool, Ordering};
33 use std::sync::OnceLock;
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 unstable_target_features = codegen_backend.target_features(sess, true);
52 sess.unstable_target_features.extend(unstable_target_features.iter().cloned());
54 let target_features = codegen_backend.target_features(sess, false);
55 sess.target_features.extend(target_features.iter().cloned());
57 cfg.extend(target_features.into_iter().map(|feat| (tf, Some(feat))));
59 if sess.crt_static(None) {
60 cfg.insert((tf, Some(sym::crt_dash_static)));
64 pub fn create_session(
65 sopts: config::Options,
66 cfg: FxHashSet<(String, Option<String>)>,
68 file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
69 input_path: Option<PathBuf>,
70 lint_caps: FxHashMap<lint::LintId, lint::Level>,
71 make_codegen_backend: Option<
72 Box<dyn FnOnce(&config::Options) -> Box<dyn CodegenBackend> + Send>,
74 descriptions: Registry,
75 ) -> (Lrc<Session>, Lrc<Box<dyn CodegenBackend>>) {
76 let codegen_backend = if let Some(make_codegen_backend) = make_codegen_backend {
77 make_codegen_backend(&sopts)
81 sopts.unstable_opts.codegen_backend.as_ref().map(|name| &name[..]),
85 // target_override is documented to be called before init(), so this is okay
86 let target_override = codegen_backend.target_override(&sopts);
88 let bundle = match rustc_errors::fluent_bundle(
89 sopts.maybe_sysroot.clone(),
91 sopts.unstable_opts.translate_lang.clone(),
92 sopts.unstable_opts.translate_additional_ftl.as_deref(),
93 sopts.unstable_opts.translate_directionality_markers,
97 early_error(sopts.error_format, &format!("failed to load fluent bundle: {e}"));
101 let mut sess = session::build_session(
111 codegen_backend.init(&sess);
113 let mut cfg = config::build_configuration(&sess, config::to_crate_config(cfg));
114 add_configuration(&mut cfg, &mut sess, &*codegen_backend);
116 let mut check_cfg = config::to_crate_check_config(check_cfg);
117 check_cfg.fill_well_known();
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 #[cfg(not(parallel_compiler))]
134 pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
139 // The thread pool is a single thread in the non-parallel compiler.
140 let mut cfg = thread::Builder::new().name("rustc".to_string());
141 if let Some(size) = get_stack_size() {
142 cfg = cfg.stack_size(size);
145 let f = move || rustc_span::create_session_globals_then(edition, f);
147 // This avoids the need for `'static` bounds.
149 // SAFETY: join() is called immediately, so any closure captures are still alive.
150 match unsafe { cfg.spawn_unchecked(f) }.unwrap().join() {
152 Err(e) => panic::resume_unwind(e),
156 /// Creates a new thread and forwards information in thread locals to it.
157 /// The new thread runs the deadlock handler.
158 /// Must only be called when a deadlock is about to happen.
159 #[cfg(parallel_compiler)]
160 unsafe fn handle_deadlock() {
161 let registry = rustc_rayon_core::Registry::current();
163 let query_map = tls::with(|tcx| {
164 QueryCtxt::from_tcx(tcx)
165 .try_collect_active_jobs()
166 .expect("active jobs shouldn't be locked in deadlock handler")
168 thread::spawn(move || rustc_query_impl::deadlock(query_map, ®istry));
171 #[cfg(parallel_compiler)]
172 pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
177 let mut config = rayon::ThreadPoolBuilder::new()
178 .thread_name(|_| "rustc".to_string())
179 .acquire_thread_handler(jobserver::acquire_thread)
180 .release_thread_handler(jobserver::release_thread)
181 .num_threads(threads)
182 .deadlock_handler(|| unsafe { handle_deadlock() });
184 if let Some(size) = get_stack_size() {
185 config = config.stack_size(size);
188 let with_pool = move |pool: &rayon::ThreadPool| pool.install(f);
190 rustc_span::create_session_globals_then(edition, || {
191 rustc_span::with_session_globals(|session_globals| {
192 // The main handler runs for each Rayon worker thread and sets up
193 // the thread local rustc uses. `session_globals` is captured and set
194 // on the new threads.
195 let main_handler = move |thread: rayon::ThreadBuilder| {
196 rustc_span::set_session_globals_then(session_globals, || thread.run())
199 config.build_scoped(main_handler, with_pool).unwrap()
204 fn load_backend_from_dylib(path: &Path) -> MakeBackendFn {
205 let lib = unsafe { Library::new(path) }.unwrap_or_else(|err| {
206 let err = format!("couldn't load codegen backend {:?}: {}", path, err);
207 early_error(ErrorOutputType::default(), &err);
210 let backend_sym = unsafe { lib.get::<MakeBackendFn>(b"__rustc_codegen_backend") }
211 .unwrap_or_else(|e| {
212 let err = format!("couldn't load codegen backend: {}", e);
213 early_error(ErrorOutputType::default(), &err);
216 // Intentionally leak the dynamic library. We can't ever unload it
217 // since the library can make things that will live arbitrarily long.
218 let backend_sym = unsafe { backend_sym.into_raw() };
224 /// Get the codegen backend based on the name and specified sysroot.
226 /// A name of `None` indicates that the default backend should be used.
227 pub fn get_codegen_backend(
228 maybe_sysroot: &Option<PathBuf>,
229 backend_name: Option<&str>,
230 ) -> Box<dyn CodegenBackend> {
231 static LOAD: OnceLock<unsafe fn() -> Box<dyn CodegenBackend>> = OnceLock::new();
233 let load = LOAD.get_or_init(|| {
234 let default_codegen_backend = option_env!("CFG_DEFAULT_CODEGEN_BACKEND").unwrap_or("llvm");
236 match backend_name.unwrap_or(default_codegen_backend) {
237 filename if filename.contains('.') => load_backend_from_dylib(filename.as_ref()),
238 #[cfg(feature = "llvm")]
239 "llvm" => rustc_codegen_llvm::LlvmCodegenBackend::new,
240 backend_name => get_codegen_sysroot(maybe_sysroot, backend_name),
244 // SAFETY: In case of a builtin codegen backend this is safe. In case of an external codegen
245 // backend we hope that the backend links against the same rustc_driver version. If this is not
246 // the case, we get UB.
250 // This is used for rustdoc, but it uses similar machinery to codegen backend
251 // loading, so we leave the code here. It is potentially useful for other tools
252 // that want to invoke the rustc binary while linking to rustc as well.
253 pub fn rustc_path<'a>() -> Option<&'a Path> {
254 static RUSTC_PATH: OnceLock<Option<PathBuf>> = OnceLock::new();
256 const BIN_PATH: &str = env!("RUSTC_INSTALL_BINDIR");
258 RUSTC_PATH.get_or_init(|| get_rustc_path_inner(BIN_PATH)).as_ref().map(|v| &**v)
261 fn get_rustc_path_inner(bin_path: &str) -> Option<PathBuf> {
262 sysroot_candidates().iter().find_map(|sysroot| {
263 let candidate = sysroot.join(bin_path).join(if cfg!(target_os = "windows") {
268 candidate.exists().then_some(candidate)
272 fn sysroot_candidates() -> Vec<PathBuf> {
273 let target = session::config::host_triple();
274 let mut sysroot_candidates = vec![filesearch::get_or_default_sysroot()];
275 let path = current_dll_path().and_then(|s| s.canonicalize().ok());
276 if let Some(dll) = path {
277 // use `parent` twice to chop off the file name and then also the
278 // directory containing the dll which should be either `lib` or `bin`.
279 if let Some(path) = dll.parent().and_then(|p| p.parent()) {
280 // The original `path` pointed at the `rustc_driver` crate's dll.
281 // Now that dll should only be in one of two locations. The first is
282 // in the compiler's libdir, for example `$sysroot/lib/*.dll`. The
283 // other is the target's libdir, for example
284 // `$sysroot/lib/rustlib/$target/lib/*.dll`.
286 // We don't know which, so let's assume that if our `path` above
287 // ends in `$target` we *could* be in the target libdir, and always
288 // assume that we may be in the main libdir.
289 sysroot_candidates.push(path.to_owned());
291 if path.ends_with(target) {
292 sysroot_candidates.extend(
293 path.parent() // chop off `$target`
294 .and_then(|p| p.parent()) // chop off `rustlib`
295 .and_then(|p| p.parent()) // chop off `lib`
296 .map(|s| s.to_owned()),
302 return sysroot_candidates;
305 fn current_dll_path() -> Option<PathBuf> {
306 use std::ffi::{CStr, OsStr};
307 use std::os::unix::prelude::*;
310 let addr = current_dll_path as usize as *mut _;
311 let mut info = mem::zeroed();
312 if libc::dladdr(addr, &mut info) == 0 {
313 info!("dladdr failed");
316 if info.dli_fname.is_null() {
317 info!("dladdr returned null pointer");
320 let bytes = CStr::from_ptr(info.dli_fname).to_bytes();
321 let os = OsStr::from_bytes(bytes);
322 Some(PathBuf::from(os))
327 fn current_dll_path() -> Option<PathBuf> {
328 use std::ffi::OsString;
330 use std::os::windows::prelude::*;
333 use winapi::um::libloaderapi::{
334 GetModuleFileNameW, GetModuleHandleExW, GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
338 let mut module = ptr::null_mut();
339 let r = GetModuleHandleExW(
340 GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
341 current_dll_path as usize as *mut _,
345 info!("GetModuleHandleExW failed: {}", io::Error::last_os_error());
348 let mut space = Vec::with_capacity(1024);
349 let r = GetModuleFileNameW(module, space.as_mut_ptr(), space.capacity() as u32);
351 info!("GetModuleFileNameW failed: {}", io::Error::last_os_error());
355 if r >= space.capacity() {
356 info!("our buffer was too small? {}", io::Error::last_os_error());
360 let os = OsString::from_wide(&space);
361 Some(PathBuf::from(os))
366 fn get_codegen_sysroot(maybe_sysroot: &Option<PathBuf>, backend_name: &str) -> MakeBackendFn {
367 // For now we only allow this function to be called once as it'll dlopen a
368 // few things, which seems to work best if we only do that once. In
369 // general this assertion never trips due to the once guard in `get_codegen_backend`,
370 // but there's a few manual calls to this function in this file we protect
372 static LOADED: AtomicBool = AtomicBool::new(false);
374 !LOADED.fetch_or(true, Ordering::SeqCst),
375 "cannot load the default codegen backend twice"
378 let target = session::config::host_triple();
379 let sysroot_candidates = sysroot_candidates();
381 let sysroot = maybe_sysroot
383 .chain(sysroot_candidates.iter())
385 filesearch::make_target_lib_path(sysroot, target).with_file_name("codegen-backends")
388 info!("codegen backend candidate: {}", f.display());
391 let sysroot = sysroot.unwrap_or_else(|| {
392 let candidates = sysroot_candidates
394 .map(|p| p.display().to_string())
398 "failed to find a `codegen-backends` folder \
399 in the sysroot candidates:\n* {}",
402 early_error(ErrorOutputType::default(), &err);
404 info!("probing {} for a codegen backend", sysroot.display());
406 let d = sysroot.read_dir().unwrap_or_else(|e| {
408 "failed to load default codegen backend, couldn't \
413 early_error(ErrorOutputType::default(), &err);
416 let mut file: Option<PathBuf> = None;
418 let expected_names = &[
419 format!("rustc_codegen_{}-{}", backend_name, release_str().expect("CFG_RELEASE")),
420 format!("rustc_codegen_{}", backend_name),
422 for entry in d.filter_map(|e| e.ok()) {
423 let path = entry.path();
424 let Some(filename) = path.file_name().and_then(|s| s.to_str()) else { continue };
425 if !(filename.starts_with(DLL_PREFIX) && filename.ends_with(DLL_SUFFIX)) {
428 let name = &filename[DLL_PREFIX.len()..filename.len() - DLL_SUFFIX.len()];
429 if !expected_names.iter().any(|expected| expected == name) {
432 if let Some(ref prev) = file {
434 "duplicate codegen backends found\n\
441 early_error(ErrorOutputType::default(), &err);
443 file = Some(path.clone());
447 Some(ref s) => load_backend_from_dylib(s),
449 let err = format!("unsupported builtin codegen backend `{}`", backend_name);
450 early_error(ErrorOutputType::default(), &err);
455 pub(crate) fn check_attr_crate_type(
457 attrs: &[ast::Attribute],
458 lint_buffer: &mut LintBuffer,
460 // Unconditionally collect crate types from attributes to make them used
461 for a in attrs.iter() {
462 if a.has_name(sym::crate_type) {
463 if let Some(n) = a.value_str() {
464 if categorize_crate_type(n).is_some() {
468 if let ast::MetaItemKind::NameValue(spanned) = a.meta_kind().unwrap() {
469 let span = spanned.span;
470 let lev_candidate = find_best_match_for_name(
471 &CRATE_TYPES.iter().map(|(k, _)| *k).collect::<Vec<_>>(),
475 if let Some(candidate) = lev_candidate {
476 lint_buffer.buffer_lint_with_diagnostic(
477 lint::builtin::UNKNOWN_CRATE_TYPES,
480 "invalid `crate_type` value",
481 BuiltinLintDiagnostics::UnknownCrateTypes(
483 "did you mean".to_string(),
484 format!("\"{}\"", candidate),
488 lint_buffer.buffer_lint(
489 lint::builtin::UNKNOWN_CRATE_TYPES,
492 "invalid `crate_type` value",
497 // This is here mainly to check for using a macro, such as
498 // #![crate_type = foo!()]. That is not supported since the
499 // crate type needs to be known very early in compilation long
500 // before expansion. Otherwise, validation would normally be
501 // caught in AstValidator (via `check_builtin_attribute`), but
502 // by the time that runs the macro is expanded, and it doesn't
504 validate_attr::emit_fatal_malformed_builtin_attribute(
514 const CRATE_TYPES: &[(Symbol, CrateType)] = &[
515 (sym::rlib, CrateType::Rlib),
516 (sym::dylib, CrateType::Dylib),
517 (sym::cdylib, CrateType::Cdylib),
518 (sym::lib, config::default_lib_output()),
519 (sym::staticlib, CrateType::Staticlib),
520 (sym::proc_dash_macro, CrateType::ProcMacro),
521 (sym::bin, CrateType::Executable),
524 fn categorize_crate_type(s: Symbol) -> Option<CrateType> {
525 Some(CRATE_TYPES.iter().find(|(key, _)| *key == s)?.1)
528 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<CrateType> {
529 // Unconditionally collect crate types from attributes to make them used
530 let attr_types: Vec<CrateType> = attrs
533 if a.has_name(sym::crate_type) {
534 match a.value_str() {
535 Some(s) => categorize_crate_type(s),
544 // If we're generating a test executable, then ignore all other output
545 // styles at all other locations
546 if session.opts.test {
547 return vec![CrateType::Executable];
550 // Only check command line flags if present. If no types are specified by
551 // command line, then reuse the empty `base` Vec to hold the types that
552 // will be found in crate attributes.
553 // JUSTIFICATION: before wrapper fn is available
554 #[allow(rustc::bad_opt_access)]
555 let mut base = session.opts.crate_types.clone();
557 base.extend(attr_types);
559 base.push(output::default_output_for_target(session));
566 base.retain(|crate_type| {
567 let res = !output::invalid_output_for_target(session, *crate_type);
570 session.warn(&format!(
571 "dropping unsupported crate type `{}` for target `{}`",
572 *crate_type, session.opts.target_triple
582 pub fn build_output_filenames(
584 odir: &Option<PathBuf>,
585 ofile: &Option<PathBuf>,
586 temps_dir: &Option<PathBuf>,
587 attrs: &[ast::Attribute],
589 ) -> OutputFilenames {
592 // "-" as input file will cause the parser to read from stdin so we
593 // have to make up a name
594 // We want to toss everything after the final '.'
595 let dirpath = (*odir).as_ref().cloned().unwrap_or_default();
597 // If a crate name is present, we use it as the link name
602 .or_else(|| rustc_attr::find_crate_name(sess, attrs).map(|n| n.to_string()))
603 .unwrap_or_else(|| input.filestem().to_owned());
605 OutputFilenames::new(
610 sess.opts.cg.extra_filename.clone(),
611 sess.opts.output_types.clone(),
615 Some(ref out_file) => {
616 let unnamed_output_types =
617 sess.opts.output_types.values().filter(|a| a.is_none()).count();
618 let ofile = if unnamed_output_types > 1 {
620 "due to multiple output types requested, the explicitly specified \
621 output file name will be adapted for each output type",
625 if !sess.opts.cg.extra_filename.is_empty() {
626 sess.warn("ignoring -C extra-filename flag due to -o flag");
628 Some(out_file.clone())
631 sess.warn("ignoring --out-dir flag due to -o flag");
634 OutputFilenames::new(
635 out_file.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),
636 out_file.file_stem().unwrap_or_default().to_str().unwrap().to_string(),
639 sess.opts.cg.extra_filename.clone(),
640 sess.opts.output_types.clone(),
646 /// Returns a version string such as "1.46.0 (04488afe3 2020-08-24)"
647 pub fn version_str() -> Option<&'static str> {
648 option_env!("CFG_VERSION")
651 /// Returns a version string such as "0.12.0-dev".
652 pub fn release_str() -> Option<&'static str> {
653 option_env!("CFG_RELEASE")
656 /// Returns the full SHA1 hash of HEAD of the Git repo from which rustc was built.
657 pub fn commit_hash_str() -> Option<&'static str> {
658 option_env!("CFG_VER_HASH")
661 /// Returns the "commit date" of HEAD of the Git repo from which rustc was built as a static string.
662 pub fn commit_date_str() -> Option<&'static str> {
663 option_env!("CFG_VER_DATE")