1 //! Validates all used crates and extern libraries and loads their metadata
4 ConflictingAllocErrorHandler, ConflictingGlobalAlloc, CrateNotPanicRuntime,
5 GlobalAllocRequired, NoMultipleAllocErrorHandler, NoMultipleGlobalAlloc, NoPanicStrategy,
6 NoTransitiveNeedsDep, NotProfilerRuntime, ProfilerBuiltinsNeedsCore,
8 use crate::locator::{CrateError, CrateLocator, CratePaths};
9 use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
11 use rustc_ast::expand::allocator::AllocatorKind;
12 use rustc_ast::{self as ast, *};
13 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
14 use rustc_data_structures::svh::Svh;
15 use rustc_data_structures::sync::{Lrc, ReadGuard};
16 use rustc_expand::base::SyntaxExtension;
17 use rustc_hir::def_id::{CrateNum, LocalDefId, StableCrateId, LOCAL_CRATE};
18 use rustc_hir::definitions::Definitions;
19 use rustc_index::vec::IndexVec;
20 use rustc_middle::ty::TyCtxt;
21 use rustc_session::config::{self, CrateType, ExternLocation};
22 use rustc_session::cstore::{CrateDepKind, CrateSource, ExternCrate};
23 use rustc_session::cstore::{ExternCrateSource, MetadataLoaderDyn};
24 use rustc_session::lint;
25 use rustc_session::output::validate_crate_name;
26 use rustc_session::search_paths::PathKind;
27 use rustc_session::Session;
28 use rustc_span::edition::Edition;
29 use rustc_span::symbol::{sym, Symbol};
30 use rustc_span::{Span, DUMMY_SP};
31 use rustc_target::spec::{PanicStrategy, TargetTriple};
33 use proc_macro::bridge::client::ProcMacro;
40 metas: IndexVec<CrateNum, Option<Lrc<CrateMetadata>>>,
41 injected_panic_runtime: Option<CrateNum>,
42 /// This crate needs an allocator and either provides it itself, or finds it in a dependency.
43 /// If the above is true, then this field denotes the kind of the found allocator.
44 allocator_kind: Option<AllocatorKind>,
45 /// This crate needs an allocation error handler and either provides it itself, or finds it in a dependency.
46 /// If the above is true, then this field denotes the kind of the found allocator.
47 alloc_error_handler_kind: Option<AllocatorKind>,
48 /// This crate has a `#[global_allocator]` item.
49 has_global_allocator: bool,
50 /// This crate has a `#[alloc_error_handler]` item.
51 has_alloc_error_handler: bool,
53 /// This map is used to verify we get no hash conflicts between
54 /// `StableCrateId` values.
55 pub(crate) stable_crate_ids: FxHashMap<StableCrateId, CrateNum>,
57 /// Unused externs of the crate
58 unused_externs: Vec<Symbol>,
61 impl std::fmt::Debug for CStore {
62 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
63 f.debug_struct("CStore").finish_non_exhaustive()
67 pub struct CrateLoader<'a> {
68 // Immutable configuration.
70 metadata_loader: &'a MetadataLoaderDyn,
71 definitions: ReadGuard<'a, Definitions>,
72 local_crate_name: Symbol,
74 cstore: &'a mut CStore,
75 used_extern_options: &'a mut FxHashSet<Symbol>,
78 pub enum LoadedMacro {
79 MacroDef(ast::Item, Edition),
80 ProcMacro(SyntaxExtension),
83 pub(crate) struct Library {
84 pub source: CrateSource,
85 pub metadata: MetadataBlob,
93 /// A reference to `CrateMetadata` that can also give access to whole crate store when necessary.
94 #[derive(Clone, Copy)]
95 pub(crate) struct CrateMetadataRef<'a> {
96 pub cdata: &'a CrateMetadata,
97 pub cstore: &'a CStore,
100 impl std::ops::Deref for CrateMetadataRef<'_> {
101 type Target = CrateMetadata;
103 fn deref(&self) -> &Self::Target {
108 struct CrateDump<'a>(&'a CStore);
110 impl<'a> std::fmt::Debug for CrateDump<'a> {
111 fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
112 writeln!(fmt, "resolved crates:")?;
113 for (cnum, data) in self.0.iter_crate_data() {
114 writeln!(fmt, " name: {}", data.name())?;
115 writeln!(fmt, " cnum: {}", cnum)?;
116 writeln!(fmt, " hash: {}", data.hash())?;
117 writeln!(fmt, " reqd: {:?}", data.dep_kind())?;
118 let CrateSource { dylib, rlib, rmeta } = data.source();
119 if let Some(dylib) = dylib {
120 writeln!(fmt, " dylib: {}", dylib.0.display())?;
122 if let Some(rlib) = rlib {
123 writeln!(fmt, " rlib: {}", rlib.0.display())?;
125 if let Some(rmeta) = rmeta {
126 writeln!(fmt, " rmeta: {}", rmeta.0.display())?;
134 pub fn from_tcx(tcx: TyCtxt<'_>) -> &CStore {
135 tcx.cstore_untracked()
137 .downcast_ref::<CStore>()
138 .expect("`tcx.cstore` is not a `CStore`")
141 fn alloc_new_crate_num(&mut self) -> CrateNum {
142 self.metas.push(None);
143 CrateNum::new(self.metas.len() - 1)
146 pub fn has_crate_data(&self, cnum: CrateNum) -> bool {
147 self.metas[cnum].is_some()
150 pub(crate) fn get_crate_data(&self, cnum: CrateNum) -> CrateMetadataRef<'_> {
151 let cdata = self.metas[cnum]
153 .unwrap_or_else(|| panic!("Failed to get crate data for {:?}", cnum));
154 CrateMetadataRef { cdata, cstore: self }
157 fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
158 assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
159 self.metas[cnum] = Some(Lrc::new(data));
162 pub(crate) fn iter_crate_data(&self) -> impl Iterator<Item = (CrateNum, &CrateMetadata)> {
165 .filter_map(|(cnum, data)| data.as_deref().map(|data| (cnum, data)))
168 fn push_dependencies_in_postorder(&self, deps: &mut Vec<CrateNum>, cnum: CrateNum) {
169 if !deps.contains(&cnum) {
170 let data = self.get_crate_data(cnum);
171 for &dep in data.dependencies().iter() {
173 self.push_dependencies_in_postorder(deps, dep);
181 pub(crate) fn crate_dependencies_in_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
182 let mut deps = Vec::new();
183 if cnum == LOCAL_CRATE {
184 for (cnum, _) in self.iter_crate_data() {
185 self.push_dependencies_in_postorder(&mut deps, cnum);
188 self.push_dependencies_in_postorder(&mut deps, cnum);
193 fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
194 let mut deps = self.crate_dependencies_in_postorder(cnum);
199 pub(crate) fn injected_panic_runtime(&self) -> Option<CrateNum> {
200 self.injected_panic_runtime
203 pub(crate) fn allocator_kind(&self) -> Option<AllocatorKind> {
207 pub(crate) fn alloc_error_handler_kind(&self) -> Option<AllocatorKind> {
208 self.alloc_error_handler_kind
211 pub(crate) fn has_global_allocator(&self) -> bool {
212 self.has_global_allocator
215 pub(crate) fn has_alloc_error_handler(&self) -> bool {
216 self.has_alloc_error_handler
219 pub fn report_unused_deps(&self, tcx: TyCtxt<'_>) {
220 let json_unused_externs = tcx.sess.opts.json_unused_externs;
222 // We put the check for the option before the lint_level_at_node call
223 // because the call mutates internal state and introducing it
224 // leads to some ui tests failing.
225 if !json_unused_externs.is_enabled() {
229 .lint_level_at_node(lint::builtin::UNUSED_CRATE_DEPENDENCIES, rustc_hir::CRATE_HIR_ID)
231 if level != lint::Level::Allow {
233 self.unused_externs.iter().map(|ident| ident.to_ident_string()).collect::<Vec<_>>();
234 let unused_externs = unused_externs.iter().map(String::as_str).collect::<Vec<&str>>();
235 tcx.sess.parse_sess.span_diagnostic.emit_unused_externs(
237 json_unused_externs.is_loud(),
243 pub fn new(sess: &Session) -> CStore {
244 let mut stable_crate_ids = FxHashMap::default();
245 stable_crate_ids.insert(sess.local_stable_crate_id(), LOCAL_CRATE);
247 // We add an empty entry for LOCAL_CRATE (which maps to zero) in
248 // order to make array indices in `metas` match with the
249 // corresponding `CrateNum`. This first entry will always remain
251 metas: IndexVec::from_elem_n(None, 1),
252 injected_panic_runtime: None,
253 allocator_kind: None,
254 alloc_error_handler_kind: None,
255 has_global_allocator: false,
256 has_alloc_error_handler: false,
258 unused_externs: Vec::new(),
263 impl<'a> CrateLoader<'a> {
266 metadata_loader: &'a MetadataLoaderDyn,
267 local_crate_name: Symbol,
268 cstore: &'a mut CStore,
269 definitions: ReadGuard<'a, Definitions>,
270 used_extern_options: &'a mut FxHashSet<Symbol>,
281 pub fn cstore(&self) -> &CStore {
285 fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
286 for (cnum, data) in self.cstore.iter_crate_data() {
287 if data.name() != name {
288 trace!("{} did not match {}", data.name(), name);
293 Some(hash) if hash == data.hash() => return Some(cnum),
295 debug!("actual hash {} did not match expected {}", hash, data.hash());
301 // When the hash is None we're dealing with a top-level dependency
302 // in which case we may have a specification on the command line for
303 // this library. Even though an upstream library may have loaded
304 // something of the same name, we have to make sure it was loaded
305 // from the exact same location as well.
307 // We're also sure to compare *paths*, not actual byte slices. The
308 // `source` stores paths which are normalized which may be different
309 // from the strings on the command line.
310 let source = self.cstore.get_crate_data(cnum).cdata.source();
311 if let Some(entry) = self.sess.opts.externs.get(name.as_str()) {
312 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
313 if let Some(mut files) = entry.files() {
315 let l = l.canonicalized();
316 source.dylib.as_ref().map(|(p, _)| p) == Some(l)
317 || source.rlib.as_ref().map(|(p, _)| p) == Some(l)
318 || source.rmeta.as_ref().map(|(p, _)| p) == Some(l)
326 // Alright, so we've gotten this far which means that `data` has the
327 // right name, we don't have a hash, and we don't have a --extern
328 // pointing for ourselves. We're still not quite yet done because we
329 // have to make sure that this crate was found in the crate lookup
330 // path (this is a top-level dependency) as we don't want to
331 // implicitly load anything inside the dependency lookup path.
332 let prev_kind = source
335 .or(source.rlib.as_ref())
336 .or(source.rmeta.as_ref())
337 .expect("No sources for crate")
339 if kind.matches(prev_kind) {
343 "failed to load existing crate {}; kind {:?} did not match prev_kind {:?}",
344 name, kind, prev_kind
352 fn verify_no_symbol_conflicts(&self, root: &CrateRoot) -> Result<(), CrateError> {
353 // Check for (potential) conflicts with the local crate
354 if self.sess.local_stable_crate_id() == root.stable_crate_id() {
355 return Err(CrateError::SymbolConflictsCurrent(root.name()));
358 // Check for conflicts with any crate loaded so far
359 for (_, other) in self.cstore.iter_crate_data() {
360 // Same stable crate id but different SVH
361 if other.stable_crate_id() == root.stable_crate_id() && other.hash() != root.hash() {
362 return Err(CrateError::SymbolConflictsOthers(root.name()));
369 fn verify_no_stable_crate_id_hash_conflicts(
373 ) -> Result<(), CrateError> {
374 if let Some(existing) = self.cstore.stable_crate_ids.insert(root.stable_crate_id(), cnum) {
375 let crate_name0 = root.name();
376 let crate_name1 = self.cstore.get_crate_data(existing).name();
377 return Err(CrateError::StableCrateIdCollision(crate_name0, crate_name1));
385 host_lib: Option<Library>,
386 root: Option<&CratePaths>,
388 dep_kind: CrateDepKind,
390 ) -> Result<CrateNum, CrateError> {
391 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
393 let Library { source, metadata } = lib;
394 let crate_root = metadata.get_root();
395 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
398 self.sess.opts.externs.get(name.as_str()).map_or(false, |e| e.is_private_dep);
400 // Claim this crate number and cache it
401 let cnum = self.cstore.alloc_new_crate_num();
404 "register crate `{}` (cnum = {}. private_dep = {})",
410 // Maintain a reference to the top most crate.
411 // Stash paths for top-most crate locally if necessary.
413 let root = if let Some(root) = root {
416 crate_paths = CratePaths::new(crate_root.name(), source.clone());
420 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, dep_kind)?;
422 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
424 let (dlsym_source, dlsym_root) = match &host_lib {
425 Some(host_lib) => (&host_lib.source, {
426 temp_root = host_lib.metadata.get_root();
429 None => (&source, &crate_root),
431 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
432 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.stable_crate_id())?)
437 // Perform some verification *after* resolve_crate_deps() above is
438 // known to have been successful. It seems that - in error cases - the
439 // cstore can be in a temporarily invalid state between cnum allocation
440 // and dependency resolution and the verification code would produce
441 // ICEs in that case (see #83045).
442 self.verify_no_symbol_conflicts(&crate_root)?;
443 self.verify_no_stable_crate_id_hash_conflicts(&crate_root, cnum)?;
445 let crate_metadata = CrateMetadata::new(
459 self.cstore.set_crate_data(cnum, crate_metadata);
464 fn load_proc_macro<'b>(
466 locator: &mut CrateLocator<'b>,
468 host_hash: Option<Svh>,
469 ) -> Result<Option<(LoadResult, Option<Library>)>, CrateError>
473 // Use a new crate locator so trying to load a proc macro doesn't affect the error
475 let mut proc_macro_locator = locator.clone();
477 // Try to load a proc macro
478 proc_macro_locator.is_proc_macro = true;
480 // Load the proc macro crate for the target
481 let (locator, target_result) = if self.sess.opts.unstable_opts.dual_proc_macros {
482 proc_macro_locator.reset();
483 let result = match self.load(&mut proc_macro_locator)? {
484 Some(LoadResult::Previous(cnum)) => {
485 return Ok(Some((LoadResult::Previous(cnum), None)));
487 Some(LoadResult::Loaded(library)) => Some(LoadResult::Loaded(library)),
488 None => return Ok(None),
490 locator.hash = host_hash;
491 // Use the locator when looking for the host proc macro crate, as that is required
492 // so we want it to affect the error message
495 (&mut proc_macro_locator, None)
498 // Load the proc macro crate for the host
501 locator.is_proc_macro = true;
502 locator.target = &self.sess.host;
503 locator.triple = TargetTriple::from_triple(config::host_triple());
504 locator.filesearch = self.sess.host_filesearch(path_kind);
506 let Some(host_result) = self.load(locator)? else {
510 Ok(Some(if self.sess.opts.unstable_opts.dual_proc_macros {
511 let host_result = match host_result {
512 LoadResult::Previous(..) => {
513 panic!("host and target proc macros must be loaded in lock-step")
515 LoadResult::Loaded(library) => library,
517 (target_result.unwrap(), Some(host_result))
527 dep_kind: CrateDepKind,
528 ) -> Option<CrateNum> {
529 self.used_extern_options.insert(name);
530 match self.maybe_resolve_crate(name, dep_kind, None) {
531 Ok(cnum) => Some(cnum),
534 self.maybe_resolve_crate(sym::core, CrateDepKind::Explicit, None).is_err();
535 err.report(&self.sess, span, missing_core);
541 fn maybe_resolve_crate<'b>(
544 mut dep_kind: CrateDepKind,
545 dep: Option<(&'b CratePaths, &'b CrateDep)>,
546 ) -> Result<CrateNum, CrateError> {
547 info!("resolving crate `{}`", name);
548 if !name.as_str().is_ascii() {
549 return Err(CrateError::NonAsciiName(name));
551 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
552 Some((root, dep)) => (
556 Some(&dep.extra_filename[..]),
557 PathKind::Dependency,
559 None => (None, None, None, None, PathKind::Crate),
561 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
562 (LoadResult::Previous(cnum), None)
564 info!("falling back to a load");
565 let mut locator = CrateLocator::new(
567 &*self.metadata_loader,
575 match self.load(&mut locator)? {
576 Some(res) => (res, None),
578 dep_kind = CrateDepKind::MacrosOnly;
579 match self.load_proc_macro(&mut locator, path_kind, host_hash)? {
581 None => return Err(locator.into_error(root.cloned())),
588 (LoadResult::Previous(cnum), None) => {
589 let data = self.cstore.get_crate_data(cnum);
590 if data.is_proc_macro_crate() {
591 dep_kind = CrateDepKind::MacrosOnly;
593 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
596 (LoadResult::Loaded(library), host_library) => {
597 self.register_crate(host_library, root, library, dep_kind, name)
603 fn load(&self, locator: &mut CrateLocator<'_>) -> Result<Option<LoadResult>, CrateError> {
604 let Some(library) = locator.maybe_load_library_crate()? else {
608 // In the case that we're loading a crate, but not matching
609 // against a hash, we could load a crate which has the same hash
610 // as an already loaded crate. If this is the case prevent
611 // duplicates by just using the first crate.
613 // Note that we only do this for target triple crates, though, as we
614 // don't want to match a host crate against an equivalent target one
616 let root = library.metadata.get_root();
617 // FIXME: why is this condition necessary? It was adding in #33625 but I
618 // don't know why and the original author doesn't remember ...
619 let can_reuse_cratenum =
620 locator.triple == self.sess.opts.target_triple || locator.is_proc_macro;
621 Ok(Some(if can_reuse_cratenum {
622 let mut result = LoadResult::Loaded(library);
623 for (cnum, data) in self.cstore.iter_crate_data() {
624 if data.name() == root.name() && root.hash() == data.hash() {
625 assert!(locator.hash.is_none());
626 info!("load success, going to previous cnum: {}", cnum);
627 result = LoadResult::Previous(cnum);
633 LoadResult::Loaded(library)
637 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
638 let cmeta = self.cstore.get_crate_data(cnum);
639 if cmeta.update_extern_crate(extern_crate) {
640 // Propagate the extern crate info to dependencies if it was updated.
641 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
642 for &dep_cnum in cmeta.dependencies().iter() {
643 self.update_extern_crate(dep_cnum, extern_crate);
648 // Go through the crate metadata and load any crates that it references
649 fn resolve_crate_deps(
652 crate_root: &CrateRoot,
653 metadata: &MetadataBlob,
655 dep_kind: CrateDepKind,
656 ) -> Result<CrateNumMap, CrateError> {
657 debug!("resolving deps of external crate");
658 if crate_root.is_proc_macro_crate() {
659 return Ok(CrateNumMap::new());
662 // The map from crate numbers in the crate we're resolving to local crate numbers.
663 // We map 0 and all other holes in the map to our parent crate. The "additional"
664 // self-dependencies should be harmless.
665 let deps = crate_root.decode_crate_deps(metadata);
666 let mut crate_num_map = CrateNumMap::with_capacity(1 + deps.len());
667 crate_num_map.push(krate);
670 "resolving dep crate {} hash: `{}` extra filename: `{}`",
671 dep.name, dep.hash, dep.extra_filename
673 let dep_kind = match dep_kind {
674 CrateDepKind::MacrosOnly => CrateDepKind::MacrosOnly,
677 let cnum = self.maybe_resolve_crate(dep.name, dep_kind, Some((root, &dep)))?;
678 crate_num_map.push(cnum);
681 debug!("resolve_crate_deps: cnum_map for {:?} is {:?}", krate, crate_num_map);
685 fn dlsym_proc_macros(
688 stable_crate_id: StableCrateId,
689 ) -> Result<&'static [ProcMacro], CrateError> {
690 // Make sure the path contains a / or the linker will search for it.
691 let path = env::current_dir().unwrap().join(path);
692 let lib = unsafe { libloading::Library::new(path) }
693 .map_err(|err| CrateError::DlOpen(err.to_string()))?;
695 let sym_name = self.sess.generate_proc_macro_decls_symbol(stable_crate_id);
696 let sym = unsafe { lib.get::<*const &[ProcMacro]>(sym_name.as_bytes()) }
697 .map_err(|err| CrateError::DlSym(err.to_string()))?;
699 // Intentionally leak the dynamic library. We can't ever unload it
700 // since the library can make things that will live arbitrarily long.
701 let sym = unsafe { sym.into_raw() };
702 std::mem::forget(lib);
707 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
708 // If we're only compiling an rlib, then there's no need to select a
709 // panic runtime, so we just skip this section entirely.
710 let any_non_rlib = self.sess.crate_types().iter().any(|ct| *ct != CrateType::Rlib);
712 info!("panic runtime injection skipped, only generating rlib");
716 // If we need a panic runtime, we try to find an existing one here. At
717 // the same time we perform some general validation of the DAG we've got
718 // going such as ensuring everything has a compatible panic strategy.
720 // The logic for finding the panic runtime here is pretty much the same
721 // as the allocator case with the only addition that the panic strategy
722 // compilation mode also comes into play.
723 let desired_strategy = self.sess.panic_strategy();
724 let mut runtime_found = false;
725 let mut needs_panic_runtime =
726 self.sess.contains_name(&krate.attrs, sym::needs_panic_runtime);
728 for (cnum, data) in self.cstore.iter_crate_data() {
729 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
730 if data.is_panic_runtime() {
731 // Inject a dependency from all #![needs_panic_runtime] to this
732 // #![panic_runtime] crate.
733 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
734 data.needs_panic_runtime()
736 runtime_found = runtime_found || data.dep_kind() == CrateDepKind::Explicit;
740 // If an explicitly linked and matching panic runtime was found, or if
741 // we just don't need one at all, then we're done here and there's
742 // nothing else to do.
743 if !needs_panic_runtime || runtime_found {
747 // By this point we know that we (a) need a panic runtime and (b) no
748 // panic runtime was explicitly linked. Here we just load an appropriate
749 // default runtime for our panic strategy and then inject the
752 // We may resolve to an already loaded crate (as the crate may not have
753 // been explicitly linked prior to this) and we may re-inject
754 // dependencies again, but both of those situations are fine.
756 // Also note that we have yet to perform validation of the crate graph
757 // in terms of everyone has a compatible panic runtime format, that's
758 // performed later as part of the `dependency_format` module.
759 let name = match desired_strategy {
760 PanicStrategy::Unwind => sym::panic_unwind,
761 PanicStrategy::Abort => sym::panic_abort,
763 info!("panic runtime not found -- loading {}", name);
765 let Some(cnum) = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit) else { return; };
766 let data = self.cstore.get_crate_data(cnum);
768 // Sanity check the loaded crate to ensure it is indeed a panic runtime
769 // and the panic strategy is indeed what we thought it was.
770 if !data.is_panic_runtime() {
771 self.sess.emit_err(CrateNotPanicRuntime { crate_name: name });
773 if data.required_panic_strategy() != Some(desired_strategy) {
774 self.sess.emit_err(NoPanicStrategy { crate_name: name, strategy: desired_strategy });
777 self.cstore.injected_panic_runtime = Some(cnum);
778 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
781 fn inject_profiler_runtime(&mut self, krate: &ast::Crate) {
782 if self.sess.opts.unstable_opts.no_profiler_runtime
783 || !(self.sess.instrument_coverage()
784 || self.sess.opts.unstable_opts.profile
785 || self.sess.opts.cg.profile_generate.enabled())
790 info!("loading profiler");
792 let name = Symbol::intern(&self.sess.opts.unstable_opts.profiler_runtime);
793 if name == sym::profiler_builtins && self.sess.contains_name(&krate.attrs, sym::no_core) {
794 self.sess.emit_err(ProfilerBuiltinsNeedsCore);
797 let Some(cnum) = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit) else { return; };
798 let data = self.cstore.get_crate_data(cnum);
800 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
801 if !data.is_profiler_runtime() {
802 self.sess.emit_err(NotProfilerRuntime { crate_name: name });
806 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
807 self.cstore.has_global_allocator = match &*global_allocator_spans(&self.sess, krate) {
808 [span1, span2, ..] => {
809 self.sess.emit_err(NoMultipleGlobalAlloc { span2: *span2, span1: *span1 });
812 spans => !spans.is_empty(),
814 self.cstore.has_alloc_error_handler = match &*alloc_error_handler_spans(&self.sess, krate) {
815 [span1, span2, ..] => {
816 self.sess.emit_err(NoMultipleAllocErrorHandler { span2: *span2, span1: *span1 });
819 spans => !spans.is_empty(),
822 // Check to see if we actually need an allocator. This desire comes
823 // about through the `#![needs_allocator]` attribute and is typically
824 // written down in liballoc.
825 if !self.sess.contains_name(&krate.attrs, sym::needs_allocator)
826 && !self.cstore.iter_crate_data().any(|(_, data)| data.needs_allocator())
831 // At this point we've determined that we need an allocator. Let's see
832 // if our compilation session actually needs an allocator based on what
834 let all_rlib = self.sess.crate_types().iter().all(|ct| matches!(*ct, CrateType::Rlib));
839 // Ok, we need an allocator. Not only that but we're actually going to
840 // create an artifact that needs one linked in. Let's go find the one
841 // that we're going to link in.
843 // First up we check for global allocators. Look at the crate graph here
844 // and see what's a global allocator, including if we ourselves are a
846 let mut global_allocator =
847 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
848 for (_, data) in self.cstore.iter_crate_data() {
849 if data.has_global_allocator() {
850 match global_allocator {
851 Some(other_crate) => {
852 self.sess.emit_err(ConflictingGlobalAlloc {
853 crate_name: data.name(),
854 other_crate_name: other_crate,
857 None => global_allocator = Some(data.name()),
861 let mut alloc_error_handler =
862 self.cstore.has_alloc_error_handler.then(|| Symbol::intern("this crate"));
863 for (_, data) in self.cstore.iter_crate_data() {
864 if data.has_alloc_error_handler() {
865 match alloc_error_handler {
866 Some(other_crate) => {
867 self.sess.emit_err(ConflictingAllocErrorHandler {
868 crate_name: data.name(),
869 other_crate_name: other_crate,
872 None => alloc_error_handler = Some(data.name()),
877 if global_allocator.is_some() {
878 self.cstore.allocator_kind = Some(AllocatorKind::Global);
880 // Ok we haven't found a global allocator but we still need an
881 // allocator. At this point our allocator request is typically fulfilled
882 // by the standard library, denoted by the `#![default_lib_allocator]`
884 if !self.sess.contains_name(&krate.attrs, sym::default_lib_allocator)
885 && !self.cstore.iter_crate_data().any(|(_, data)| data.has_default_lib_allocator())
887 self.sess.emit_err(GlobalAllocRequired);
889 self.cstore.allocator_kind = Some(AllocatorKind::Default);
892 if alloc_error_handler.is_some() {
893 self.cstore.alloc_error_handler_kind = Some(AllocatorKind::Global);
895 // The alloc crate provides a default allocation error handler if
896 // one isn't specified.
897 self.cstore.alloc_error_handler_kind = Some(AllocatorKind::Default);
901 fn inject_dependency_if(
905 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
907 // don't perform this validation if the session has errors, as one of
908 // those errors may indicate a circular dependency which could cause
909 // this to stack overflow.
910 if self.sess.has_errors().is_some() {
914 // Before we inject any dependencies, make sure we don't inject a
915 // circular dependency by validating that this crate doesn't
916 // transitively depend on any crates satisfying `needs_dep`.
917 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
918 let data = self.cstore.get_crate_data(dep);
919 if needs_dep(&data) {
920 self.sess.emit_err(NoTransitiveNeedsDep {
921 crate_name: self.cstore.get_crate_data(krate).name(),
922 needs_crate_name: what,
923 deps_crate_name: data.name(),
928 // All crates satisfying `needs_dep` do not explicitly depend on the
929 // crate provided for this compile, but in order for this compilation to
930 // be successfully linked we need to inject a dependency (to order the
931 // crates on the command line correctly).
932 for (cnum, data) in self.cstore.iter_crate_data() {
934 info!("injecting a dep from {} to {}", cnum, krate);
935 data.add_dependency(krate);
940 fn report_unused_deps(&mut self, krate: &ast::Crate) {
941 // Make a point span rather than covering the whole file
942 let span = krate.spans.inner_span.shrink_to_lo();
943 // Complain about anything left over
944 for (name, entry) in self.sess.opts.externs.iter() {
945 if let ExternLocation::FoundInLibrarySearchDirectories = entry.location {
946 // Don't worry about pathless `--extern foo` sysroot references
949 if entry.nounused_dep {
950 // We're not worried about this one
953 let name_interned = Symbol::intern(name);
954 if self.used_extern_options.contains(&name_interned) {
958 // Got a real unused --extern
959 if self.sess.opts.json_unused_externs.is_enabled() {
960 self.cstore.unused_externs.push(name_interned);
964 self.sess.parse_sess.buffer_lint(
965 lint::builtin::UNUSED_CRATE_DEPENDENCIES,
969 "external crate `{}` unused in `{}`: remove the dependency or add `use {} as _;`",
971 self.local_crate_name,
977 pub fn postprocess(&mut self, krate: &ast::Crate) {
978 self.inject_profiler_runtime(krate);
979 self.inject_allocator_crate(krate);
980 self.inject_panic_runtime(krate);
982 self.report_unused_deps(krate);
984 info!("{:?}", CrateDump(&self.cstore));
987 pub fn process_extern_crate(
991 ) -> Option<CrateNum> {
993 ast::ItemKind::ExternCrate(orig_name) => {
995 "resolving extern crate stmt. ident: {} orig_name: {:?}",
996 item.ident, orig_name
998 let name = match orig_name {
1000 validate_crate_name(self.sess, orig_name, Some(item.span));
1003 None => item.ident.name,
1005 let dep_kind = if self.sess.contains_name(&item.attrs, sym::no_link) {
1006 CrateDepKind::MacrosOnly
1008 CrateDepKind::Explicit
1011 let cnum = self.resolve_crate(name, item.span, dep_kind)?;
1013 let path_len = self.definitions.def_path(def_id).data.len();
1014 self.update_extern_crate(
1017 src: ExternCrateSource::Extern(def_id.to_def_id()),
1020 dependency_of: LOCAL_CRATE,
1029 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> Option<CrateNum> {
1030 let cnum = self.resolve_crate(name, span, CrateDepKind::Explicit)?;
1032 self.update_extern_crate(
1035 src: ExternCrateSource::Path,
1037 // to have the least priority in `update_extern_crate`
1038 path_len: usize::MAX,
1039 dependency_of: LOCAL_CRATE,
1046 pub fn maybe_process_path_extern(&mut self, name: Symbol) -> Option<CrateNum> {
1047 self.maybe_resolve_crate(name, CrateDepKind::Explicit, None).ok()
1051 fn global_allocator_spans(sess: &Session, krate: &ast::Crate) -> Vec<Span> {
1057 impl<'ast, 'a> visit::Visitor<'ast> for Finder<'a> {
1058 fn visit_item(&mut self, item: &'ast ast::Item) {
1059 if item.ident.name == self.name
1060 && self.sess.contains_name(&item.attrs, sym::rustc_std_internal_symbol)
1062 self.spans.push(item.span);
1064 visit::walk_item(self, item)
1068 let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::alloc));
1069 let mut f = Finder { sess, name, spans: Vec::new() };
1070 visit::walk_crate(&mut f, krate);
1074 fn alloc_error_handler_spans(sess: &Session, krate: &ast::Crate) -> Vec<Span> {
1080 impl<'ast, 'a> visit::Visitor<'ast> for Finder<'a> {
1081 fn visit_item(&mut self, item: &'ast ast::Item) {
1082 if item.ident.name == self.name
1083 && self.sess.contains_name(&item.attrs, sym::rustc_std_internal_symbol)
1085 self.spans.push(item.span);
1087 visit::walk_item(self, item)
1091 let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::oom));
1092 let mut f = Finder { sess, name, spans: Vec::new() };
1093 visit::walk_crate(&mut f, krate);