1 //! Validates all used crates and extern libraries and loads their metadata
3 use crate::locator::{CrateLocator, CratePaths};
4 use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
6 use rustc_ast::expand::allocator::{global_allocator_spans, AllocatorKind};
7 use rustc_ast::{ast, attr};
8 use rustc_data_structures::fx::FxHashSet;
9 use rustc_data_structures::svh::Svh;
10 use rustc_data_structures::sync::Lrc;
11 use rustc_errors::struct_span_err;
12 use rustc_expand::base::SyntaxExtension;
13 use rustc_hir::def_id::{CrateNum, LocalDefId, LOCAL_CRATE};
14 use rustc_hir::definitions::Definitions;
15 use rustc_index::vec::IndexVec;
16 use rustc_middle::middle::cstore::DepKind;
17 use rustc_middle::middle::cstore::{
18 CrateSource, ExternCrate, ExternCrateSource, MetadataLoaderDyn,
20 use rustc_middle::ty::TyCtxt;
21 use rustc_session::config::{self, CrateType, ExternLocation};
22 use rustc_session::lint;
23 use rustc_session::output::validate_crate_name;
24 use rustc_session::search_paths::PathKind;
25 use rustc_session::{CrateDisambiguator, Session};
26 use rustc_span::edition::Edition;
27 use rustc_span::symbol::{sym, Symbol};
28 use rustc_span::{Span, DUMMY_SP};
29 use rustc_target::spec::{PanicStrategy, TargetTriple};
31 use log::{debug, info, log_enabled};
32 use proc_macro::bridge::client::ProcMacro;
38 metas: IndexVec<CrateNum, Option<Lrc<CrateMetadata>>>,
39 injected_panic_runtime: Option<CrateNum>,
40 /// This crate needs an allocator and either provides it itself, or finds it in a dependency.
41 /// If the above is true, then this field denotes the kind of the found allocator.
42 allocator_kind: Option<AllocatorKind>,
43 /// This crate has a `#[global_allocator]` item.
44 has_global_allocator: bool,
47 pub struct CrateLoader<'a> {
48 // Immutable configuration.
50 metadata_loader: &'a MetadataLoaderDyn,
51 local_crate_name: Symbol,
54 used_extern_options: FxHashSet<Symbol>,
57 pub enum LoadedMacro {
58 MacroDef(ast::Item, Edition),
59 ProcMacro(SyntaxExtension),
62 crate struct Library {
63 pub source: CrateSource,
64 pub metadata: MetadataBlob,
73 LocatorError(CrateLocator<'a>),
76 impl<'a> LoadError<'a> {
77 fn report(self) -> ! {
79 LoadError::LocatorError(locator) => locator.report_errs(),
84 /// A reference to `CrateMetadata` that can also give access to whole crate store when necessary.
85 #[derive(Clone, Copy)]
86 crate struct CrateMetadataRef<'a> {
87 pub cdata: &'a CrateMetadata,
88 pub cstore: &'a CStore,
91 impl std::ops::Deref for CrateMetadataRef<'_> {
92 type Target = CrateMetadata;
94 fn deref(&self) -> &Self::Target {
99 fn dump_crates(cstore: &CStore) {
100 info!("resolved crates:");
101 cstore.iter_crate_data(|cnum, data| {
102 info!(" name: {}", data.name());
103 info!(" cnum: {}", cnum);
104 info!(" hash: {}", data.hash());
105 info!(" reqd: {:?}", data.dep_kind());
106 let CrateSource { dylib, rlib, rmeta } = data.source();
107 if let Some(dylib) = dylib {
108 info!(" dylib: {}", dylib.0.display());
110 if let Some(rlib) = rlib {
111 info!(" rlib: {}", rlib.0.display());
113 if let Some(rmeta) = rmeta {
114 info!(" rmeta: {}", rmeta.0.display());
120 crate fn from_tcx(tcx: TyCtxt<'_>) -> &CStore {
121 tcx.cstore_as_any().downcast_ref::<CStore>().expect("`tcx.cstore` is not a `CStore`")
124 fn alloc_new_crate_num(&mut self) -> CrateNum {
125 self.metas.push(None);
126 CrateNum::new(self.metas.len() - 1)
129 crate fn get_crate_data(&self, cnum: CrateNum) -> CrateMetadataRef<'_> {
130 let cdata = self.metas[cnum]
132 .unwrap_or_else(|| panic!("Failed to get crate data for {:?}", cnum));
133 CrateMetadataRef { cdata, cstore: self }
136 fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
137 assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
138 self.metas[cnum] = Some(Lrc::new(data));
141 crate fn iter_crate_data(&self, mut f: impl FnMut(CrateNum, &CrateMetadata)) {
142 for (cnum, data) in self.metas.iter_enumerated() {
143 if let Some(data) = data {
149 fn push_dependencies_in_postorder(&self, deps: &mut Vec<CrateNum>, cnum: CrateNum) {
150 if !deps.contains(&cnum) {
151 let data = self.get_crate_data(cnum);
152 for &dep in data.dependencies().iter() {
154 self.push_dependencies_in_postorder(deps, dep);
162 crate fn crate_dependencies_in_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
163 let mut deps = Vec::new();
164 if cnum == LOCAL_CRATE {
165 self.iter_crate_data(|cnum, _| self.push_dependencies_in_postorder(&mut deps, cnum));
167 self.push_dependencies_in_postorder(&mut deps, cnum);
172 fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
173 let mut deps = self.crate_dependencies_in_postorder(cnum);
178 crate fn injected_panic_runtime(&self) -> Option<CrateNum> {
179 self.injected_panic_runtime
182 crate fn allocator_kind(&self) -> Option<AllocatorKind> {
186 crate fn has_global_allocator(&self) -> bool {
187 self.has_global_allocator
191 impl<'a> CrateLoader<'a> {
194 metadata_loader: &'a MetadataLoaderDyn,
195 local_crate_name: &str,
200 local_crate_name: Symbol::intern(local_crate_name),
202 // We add an empty entry for LOCAL_CRATE (which maps to zero) in
203 // order to make array indices in `metas` match with the
204 // corresponding `CrateNum`. This first entry will always remain
206 metas: IndexVec::from_elem_n(None, 1),
207 injected_panic_runtime: None,
208 allocator_kind: None,
209 has_global_allocator: false,
211 used_extern_options: Default::default(),
215 pub fn cstore(&self) -> &CStore {
219 pub fn into_cstore(self) -> CStore {
223 fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
225 self.cstore.iter_crate_data(|cnum, data| {
226 if data.name() != name {
231 Some(hash) if hash == data.hash() => {
239 // When the hash is None we're dealing with a top-level dependency
240 // in which case we may have a specification on the command line for
241 // this library. Even though an upstream library may have loaded
242 // something of the same name, we have to make sure it was loaded
243 // from the exact same location as well.
245 // We're also sure to compare *paths*, not actual byte slices. The
246 // `source` stores paths which are normalized which may be different
247 // from the strings on the command line.
248 let source = self.cstore.get_crate_data(cnum).cdata.source();
249 if let Some(entry) = self.sess.opts.externs.get(&name.as_str()) {
250 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
251 if let Some(mut files) = entry.files() {
253 let l = fs::canonicalize(l).ok();
254 source.dylib.as_ref().map(|p| &p.0) == l.as_ref()
255 || source.rlib.as_ref().map(|p| &p.0) == l.as_ref()
263 // Alright, so we've gotten this far which means that `data` has the
264 // right name, we don't have a hash, and we don't have a --extern
265 // pointing for ourselves. We're still not quite yet done because we
266 // have to make sure that this crate was found in the crate lookup
267 // path (this is a top-level dependency) as we don't want to
268 // implicitly load anything inside the dependency lookup path.
269 let prev_kind = source
272 .or(source.rlib.as_ref())
273 .or(source.rmeta.as_ref())
274 .expect("No sources for crate")
276 if kind.matches(prev_kind) {
283 fn verify_no_symbol_conflicts(&self, span: Span, root: &CrateRoot<'_>) {
284 // Check for (potential) conflicts with the local crate
285 if self.local_crate_name == root.name()
286 && self.sess.local_crate_disambiguator() == root.disambiguator()
292 "the current crate is indistinguishable from one of its \
293 dependencies: it has the same crate-name `{}` and was \
294 compiled with the same `-C metadata` arguments. This \
295 will result in symbol conflicts between the two.",
301 // Check for conflicts with any crate loaded so far
302 self.cstore.iter_crate_data(|_, other| {
303 if other.name() == root.name() && // same crate-name
304 other.disambiguator() == root.disambiguator() && // same crate-disambiguator
305 other.hash() != root.hash()
312 "found two different crates with name `{}` that are \
313 not distinguished by differing `-C metadata`. This \
314 will result in symbol conflicts between the two.",
324 host_lib: Option<Library>,
325 root: Option<&CratePaths>,
331 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
333 let Library { source, metadata } = lib;
334 let crate_root = metadata.get_root();
335 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
336 self.verify_no_symbol_conflicts(span, &crate_root);
339 self.sess.opts.externs.get(&name.as_str()).map(|e| e.is_private_dep).unwrap_or(false);
341 info!("register crate `{}` (private_dep = {})", crate_root.name(), private_dep);
343 // Claim this crate number and cache it
344 let cnum = self.cstore.alloc_new_crate_num();
346 // Maintain a reference to the top most crate.
347 // Stash paths for top-most crate locally if necessary.
349 let root = if let Some(root) = root {
352 crate_paths = CratePaths::new(crate_root.name(), source.clone());
356 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, span, dep_kind);
358 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
360 let (dlsym_source, dlsym_root) = match &host_lib {
361 Some(host_lib) => (&host_lib.source, {
362 temp_root = host_lib.metadata.get_root();
365 None => (&source, &crate_root),
367 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
368 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.disambiguator(), span))
373 self.cstore.set_crate_data(
392 fn load_proc_macro<'b>(
394 locator: &mut CrateLocator<'b>,
396 ) -> Option<(LoadResult, Option<Library>)>
400 // Use a new crate locator so trying to load a proc macro doesn't affect the error
402 let mut proc_macro_locator = locator.clone();
404 // Try to load a proc macro
405 proc_macro_locator.is_proc_macro = Some(true);
407 // Load the proc macro crate for the target
408 let (locator, target_result) = if self.sess.opts.debugging_opts.dual_proc_macros {
409 proc_macro_locator.reset();
410 let result = match self.load(&mut proc_macro_locator)? {
411 LoadResult::Previous(cnum) => return Some((LoadResult::Previous(cnum), None)),
412 LoadResult::Loaded(library) => Some(LoadResult::Loaded(library)),
414 locator.hash = locator.host_hash;
415 // Use the locator when looking for the host proc macro crate, as that is required
416 // so we want it to affect the error message
419 (&mut proc_macro_locator, None)
422 // Load the proc macro crate for the host
425 locator.is_proc_macro = Some(true);
426 locator.target = &self.sess.host;
427 locator.triple = TargetTriple::from_triple(config::host_triple());
428 locator.filesearch = self.sess.host_filesearch(path_kind);
430 let host_result = self.load(locator)?;
432 Some(if self.sess.opts.debugging_opts.dual_proc_macros {
433 let host_result = match host_result {
434 LoadResult::Previous(..) => {
435 panic!("host and target proc macros must be loaded in lock-step")
437 LoadResult::Loaded(library) => library,
439 (target_result.unwrap(), Some(host_result))
445 fn resolve_crate<'b>(
450 dep: Option<(&'b CratePaths, &'b CrateDep)>,
453 self.used_extern_options.insert(name);
455 if !name.as_str().is_ascii() {
459 &format!("cannot load a crate with a non-ascii name `{}`", name,),
463 self.maybe_resolve_crate(name, span, dep_kind, dep).unwrap_or_else(|err| err.report())
466 fn maybe_resolve_crate<'b>(
470 mut dep_kind: DepKind,
471 dep: Option<(&'b CratePaths, &'b CrateDep)>,
472 ) -> Result<CrateNum, LoadError<'b>> {
473 info!("resolving crate `{}`", name);
474 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
475 Some((root, dep)) => (
479 Some(&dep.extra_filename[..]),
480 PathKind::Dependency,
482 None => (None, None, None, None, PathKind::Crate),
484 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
485 (LoadResult::Previous(cnum), None)
487 info!("falling back to a load");
488 let mut locator = CrateLocator::new(
490 self.metadata_loader,
499 Some(false), // is_proc_macro
502 self.load(&mut locator)
505 dep_kind = DepKind::MacrosOnly;
506 self.load_proc_macro(&mut locator, path_kind)
508 .ok_or_else(move || LoadError::LocatorError(locator))?
512 (LoadResult::Previous(cnum), None) => {
513 let data = self.cstore.get_crate_data(cnum);
514 if data.is_proc_macro_crate() {
515 dep_kind = DepKind::MacrosOnly;
517 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
520 (LoadResult::Loaded(library), host_library) => {
521 Ok(self.register_crate(host_library, root, span, library, dep_kind, name))
527 fn load(&self, locator: &mut CrateLocator<'_>) -> Option<LoadResult> {
528 let library = locator.maybe_load_library_crate()?;
530 // In the case that we're loading a crate, but not matching
531 // against a hash, we could load a crate which has the same hash
532 // as an already loaded crate. If this is the case prevent
533 // duplicates by just using the first crate.
535 // Note that we only do this for target triple crates, though, as we
536 // don't want to match a host crate against an equivalent target one
538 let root = library.metadata.get_root();
539 if locator.triple == self.sess.opts.target_triple {
540 let mut result = LoadResult::Loaded(library);
541 self.cstore.iter_crate_data(|cnum, data| {
542 if data.name() == root.name() && root.hash() == data.hash() {
543 assert!(locator.hash.is_none());
544 info!("load success, going to previous cnum: {}", cnum);
545 result = LoadResult::Previous(cnum);
550 Some(LoadResult::Loaded(library))
554 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
555 let cmeta = self.cstore.get_crate_data(cnum);
556 if cmeta.update_extern_crate(extern_crate) {
557 // Propagate the extern crate info to dependencies if it was updated.
558 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
559 for &dep_cnum in cmeta.dependencies().iter() {
560 self.update_extern_crate(dep_cnum, extern_crate);
565 // Go through the crate metadata and load any crates that it references
566 fn resolve_crate_deps(
569 crate_root: &CrateRoot<'_>,
570 metadata: &MetadataBlob,
575 debug!("resolving deps of external crate");
576 if crate_root.is_proc_macro_crate() {
577 return CrateNumMap::new();
580 // The map from crate numbers in the crate we're resolving to local crate numbers.
581 // We map 0 and all other holes in the map to our parent crate. The "additional"
582 // self-dependencies should be harmless.
583 std::iter::once(krate)
584 .chain(crate_root.decode_crate_deps(metadata).map(|dep| {
586 "resolving dep crate {} hash: `{}` extra filename: `{}`",
587 dep.name, dep.hash, dep.extra_filename
589 let dep_kind = match dep_kind {
590 DepKind::MacrosOnly => DepKind::MacrosOnly,
593 self.resolve_crate(dep.name, span, dep_kind, Some((root, &dep)))
598 fn dlsym_proc_macros(
601 disambiguator: CrateDisambiguator,
603 ) -> &'static [ProcMacro] {
604 use crate::dynamic_lib::DynamicLibrary;
607 // Make sure the path contains a / or the linker will search for it.
608 let path = env::current_dir().unwrap().join(path);
609 let lib = match DynamicLibrary::open(&path) {
611 Err(err) => self.sess.span_fatal(span, &err),
614 let sym = self.sess.generate_proc_macro_decls_symbol(disambiguator);
616 let sym = match lib.symbol(&sym) {
618 Err(err) => self.sess.span_fatal(span, &err),
620 *(sym as *const &[ProcMacro])
623 // Intentionally leak the dynamic library. We can't ever unload it
624 // since the library can make things that will live arbitrarily long.
625 std::mem::forget(lib);
630 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
631 // If we're only compiling an rlib, then there's no need to select a
632 // panic runtime, so we just skip this section entirely.
633 let any_non_rlib = self.sess.crate_types().iter().any(|ct| *ct != CrateType::Rlib);
635 info!("panic runtime injection skipped, only generating rlib");
639 // If we need a panic runtime, we try to find an existing one here. At
640 // the same time we perform some general validation of the DAG we've got
641 // going such as ensuring everything has a compatible panic strategy.
643 // The logic for finding the panic runtime here is pretty much the same
644 // as the allocator case with the only addition that the panic strategy
645 // compilation mode also comes into play.
646 let desired_strategy = self.sess.panic_strategy();
647 let mut runtime_found = false;
648 let mut needs_panic_runtime = attr::contains_name(&krate.attrs, sym::needs_panic_runtime);
650 self.cstore.iter_crate_data(|cnum, data| {
651 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
652 if data.is_panic_runtime() {
653 // Inject a dependency from all #![needs_panic_runtime] to this
654 // #![panic_runtime] crate.
655 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
656 data.needs_panic_runtime()
658 runtime_found = runtime_found || data.dep_kind() == DepKind::Explicit;
662 // If an explicitly linked and matching panic runtime was found, or if
663 // we just don't need one at all, then we're done here and there's
664 // nothing else to do.
665 if !needs_panic_runtime || runtime_found {
669 // By this point we know that we (a) need a panic runtime and (b) no
670 // panic runtime was explicitly linked. Here we just load an appropriate
671 // default runtime for our panic strategy and then inject the
674 // We may resolve to an already loaded crate (as the crate may not have
675 // been explicitly linked prior to this) and we may re-inject
676 // dependencies again, but both of those situations are fine.
678 // Also note that we have yet to perform validation of the crate graph
679 // in terms of everyone has a compatible panic runtime format, that's
680 // performed later as part of the `dependency_format` module.
681 let name = match desired_strategy {
682 PanicStrategy::Unwind => Symbol::intern("panic_unwind"),
683 PanicStrategy::Abort => Symbol::intern("panic_abort"),
685 info!("panic runtime not found -- loading {}", name);
687 let cnum = self.resolve_crate(name, DUMMY_SP, DepKind::Implicit, None);
688 let data = self.cstore.get_crate_data(cnum);
690 // Sanity check the loaded crate to ensure it is indeed a panic runtime
691 // and the panic strategy is indeed what we thought it was.
692 if !data.is_panic_runtime() {
693 self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
695 if data.panic_strategy() != desired_strategy {
696 self.sess.err(&format!(
697 "the crate `{}` does not have the panic \
700 desired_strategy.desc()
704 self.cstore.injected_panic_runtime = Some(cnum);
705 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
708 fn inject_profiler_runtime(&mut self) {
709 if (self.sess.opts.debugging_opts.instrument_coverage
710 || self.sess.opts.debugging_opts.profile
711 || self.sess.opts.cg.profile_generate.enabled())
712 && !self.sess.opts.debugging_opts.no_profiler_runtime
714 info!("loading profiler");
716 let name = Symbol::intern("profiler_builtins");
717 let cnum = self.resolve_crate(name, DUMMY_SP, DepKind::Implicit, None);
718 let data = self.cstore.get_crate_data(cnum);
720 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
721 if !data.is_profiler_runtime() {
722 self.sess.err("the crate `profiler_builtins` is not a profiler runtime");
727 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
728 self.cstore.has_global_allocator = match &*global_allocator_spans(krate) {
729 [span1, span2, ..] => {
731 .struct_span_err(*span2, "cannot define multiple global allocators")
732 .span_label(*span2, "cannot define a new global allocator")
733 .span_label(*span1, "previous global allocator defined here")
737 spans => !spans.is_empty(),
740 // Check to see if we actually need an allocator. This desire comes
741 // about through the `#![needs_allocator]` attribute and is typically
742 // written down in liballoc.
743 let mut needs_allocator = attr::contains_name(&krate.attrs, sym::needs_allocator);
744 self.cstore.iter_crate_data(|_, data| {
745 needs_allocator = needs_allocator || data.needs_allocator();
747 if !needs_allocator {
751 // At this point we've determined that we need an allocator. Let's see
752 // if our compilation session actually needs an allocator based on what
754 let all_rlib = self.sess.crate_types().iter().all(|ct| match *ct {
755 CrateType::Rlib => true,
762 // Ok, we need an allocator. Not only that but we're actually going to
763 // create an artifact that needs one linked in. Let's go find the one
764 // that we're going to link in.
766 // First up we check for global allocators. Look at the crate graph here
767 // and see what's a global allocator, including if we ourselves are a
769 let mut global_allocator =
770 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
771 self.cstore.iter_crate_data(|_, data| {
772 if !data.has_global_allocator() {
775 match global_allocator {
776 Some(other_crate) => {
777 self.sess.err(&format!(
778 "the `#[global_allocator]` in {} \
779 conflicts with global \
785 None => global_allocator = Some(data.name()),
788 if global_allocator.is_some() {
789 self.cstore.allocator_kind = Some(AllocatorKind::Global);
793 // Ok we haven't found a global allocator but we still need an
794 // allocator. At this point our allocator request is typically fulfilled
795 // by the standard library, denoted by the `#![default_lib_allocator]`
797 let mut has_default = attr::contains_name(&krate.attrs, sym::default_lib_allocator);
798 self.cstore.iter_crate_data(|_, data| {
799 if data.has_default_lib_allocator() {
806 "no global memory allocator found but one is \
807 required; link to std or \
808 add `#[global_allocator]` to a static item \
809 that implements the GlobalAlloc trait.",
812 self.cstore.allocator_kind = Some(AllocatorKind::Default);
815 fn inject_dependency_if(
819 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
821 // don't perform this validation if the session has errors, as one of
822 // those errors may indicate a circular dependency which could cause
823 // this to stack overflow.
824 if self.sess.has_errors() {
828 // Before we inject any dependencies, make sure we don't inject a
829 // circular dependency by validating that this crate doesn't
830 // transitively depend on any crates satisfying `needs_dep`.
831 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
832 let data = self.cstore.get_crate_data(dep);
833 if needs_dep(&data) {
834 self.sess.err(&format!(
835 "the crate `{}` cannot depend \
836 on a crate that needs {}, but \
838 self.cstore.get_crate_data(krate).name(),
845 // All crates satisfying `needs_dep` do not explicitly depend on the
846 // crate provided for this compile, but in order for this compilation to
847 // be successfully linked we need to inject a dependency (to order the
848 // crates on the command line correctly).
849 self.cstore.iter_crate_data(|cnum, data| {
850 if !needs_dep(data) {
854 info!("injecting a dep from {} to {}", cnum, krate);
855 data.add_dependency(krate);
859 fn report_unused_deps(&mut self, krate: &ast::Crate) {
860 // Make a point span rather than covering the whole file
861 let span = krate.span.shrink_to_lo();
862 // Complain about anything left over
863 for (name, entry) in self.sess.opts.externs.iter() {
864 if let ExternLocation::FoundInLibrarySearchDirectories = entry.location {
865 // Don't worry about pathless `--extern foo` sysroot references
868 if !self.used_extern_options.contains(&Symbol::intern(name)) {
869 self.sess.parse_sess.buffer_lint(
870 lint::builtin::UNUSED_CRATE_DEPENDENCIES,
874 "external crate `{}` unused in `{}`: remove the dependency or add `use {} as _;`",
876 self.local_crate_name,
883 pub fn postprocess(&mut self, krate: &ast::Crate) {
884 self.inject_profiler_runtime();
885 self.inject_allocator_crate(krate);
886 self.inject_panic_runtime(krate);
888 if log_enabled!(log::Level::Info) {
889 dump_crates(&self.cstore);
892 self.report_unused_deps(krate);
895 pub fn process_extern_crate(
898 definitions: &Definitions,
902 ast::ItemKind::ExternCrate(orig_name) => {
904 "resolving extern crate stmt. ident: {} orig_name: {:?}",
905 item.ident, orig_name
907 let name = match orig_name {
909 validate_crate_name(Some(self.sess), &orig_name.as_str(), Some(item.span));
912 None => item.ident.name,
914 let dep_kind = if attr::contains_name(&item.attrs, sym::no_link) {
920 let cnum = self.resolve_crate(name, item.span, dep_kind, None);
922 let path_len = definitions.def_path(def_id).data.len();
923 self.update_extern_crate(
926 src: ExternCrateSource::Extern(def_id.to_def_id()),
929 dependency_of: LOCAL_CRATE,
938 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> CrateNum {
939 let cnum = self.resolve_crate(name, span, DepKind::Explicit, None);
941 self.update_extern_crate(
944 src: ExternCrateSource::Path,
946 // to have the least priority in `update_extern_crate`
947 path_len: usize::MAX,
948 dependency_of: LOCAL_CRATE,
955 pub fn maybe_process_path_extern(&mut self, name: Symbol, span: Span) -> Option<CrateNum> {
956 self.maybe_resolve_crate(name, span, DepKind::Explicit, None).ok()