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::svh::Svh;
9 use rustc_data_structures::sync::Lrc;
10 use rustc_errors::struct_span_err;
11 use rustc_expand::base::SyntaxExtension;
12 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
13 use rustc_hir::definitions::Definitions;
14 use rustc_index::vec::IndexVec;
15 use rustc_middle::middle::cstore::DepKind;
16 use rustc_middle::middle::cstore::{
17 CrateSource, ExternCrate, ExternCrateSource, MetadataLoaderDyn,
19 use rustc_middle::ty::TyCtxt;
20 use rustc_session::config;
21 use rustc_session::output::validate_crate_name;
22 use rustc_session::search_paths::PathKind;
23 use rustc_session::{CrateDisambiguator, Session};
24 use rustc_span::edition::Edition;
25 use rustc_span::symbol::{sym, Symbol};
26 use rustc_span::{Span, DUMMY_SP};
27 use rustc_target::spec::{PanicStrategy, TargetTriple};
29 use log::{debug, info, log_enabled};
30 use proc_macro::bridge::client::ProcMacro;
36 metas: IndexVec<CrateNum, Option<Lrc<CrateMetadata>>>,
37 injected_panic_runtime: Option<CrateNum>,
38 /// This crate needs an allocator and either provides it itself, or finds it in a dependency.
39 /// If the above is true, then this field denotes the kind of the found allocator.
40 allocator_kind: Option<AllocatorKind>,
41 /// This crate has a `#[global_allocator]` item.
42 has_global_allocator: bool,
45 pub struct CrateLoader<'a> {
46 // Immutable configuration.
48 metadata_loader: &'a MetadataLoaderDyn,
49 local_crate_name: Symbol,
54 pub enum LoadedMacro {
55 MacroDef(ast::Item, Edition),
56 ProcMacro(SyntaxExtension),
59 crate struct Library {
60 pub source: CrateSource,
61 pub metadata: MetadataBlob,
70 LocatorError(CrateLocator<'a>),
73 impl<'a> LoadError<'a> {
74 fn report(self) -> ! {
76 LoadError::LocatorError(locator) => locator.report_errs(),
81 /// A reference to `CrateMetadata` that can also give access to whole crate store when necessary.
82 #[derive(Clone, Copy)]
83 crate struct CrateMetadataRef<'a> {
84 pub cdata: &'a CrateMetadata,
85 pub cstore: &'a CStore,
88 impl std::ops::Deref for CrateMetadataRef<'_> {
89 type Target = CrateMetadata;
91 fn deref(&self) -> &Self::Target {
96 fn dump_crates(cstore: &CStore) {
97 info!("resolved crates:");
98 cstore.iter_crate_data(|cnum, data| {
99 info!(" name: {}", data.name());
100 info!(" cnum: {}", cnum);
101 info!(" hash: {}", data.hash());
102 info!(" reqd: {:?}", data.dep_kind());
103 let CrateSource { dylib, rlib, rmeta } = data.source();
104 dylib.as_ref().map(|dl| info!(" dylib: {}", dl.0.display()));
105 rlib.as_ref().map(|rl| info!(" rlib: {}", rl.0.display()));
106 rmeta.as_ref().map(|rl| info!(" rmeta: {}", rl.0.display()));
111 crate fn from_tcx(tcx: TyCtxt<'_>) -> &CStore {
112 tcx.cstore_as_any().downcast_ref::<CStore>().expect("`tcx.cstore` is not a `CStore`")
115 fn alloc_new_crate_num(&mut self) -> CrateNum {
116 self.metas.push(None);
117 CrateNum::new(self.metas.len() - 1)
120 crate fn get_crate_data(&self, cnum: CrateNum) -> CrateMetadataRef<'_> {
121 let cdata = self.metas[cnum]
123 .unwrap_or_else(|| panic!("Failed to get crate data for {:?}", cnum));
124 CrateMetadataRef { cdata, cstore: self }
127 fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
128 assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
129 self.metas[cnum] = Some(Lrc::new(data));
132 crate fn iter_crate_data(&self, mut f: impl FnMut(CrateNum, &CrateMetadata)) {
133 for (cnum, data) in self.metas.iter_enumerated() {
134 if let Some(data) = data {
140 fn push_dependencies_in_postorder(&self, deps: &mut Vec<CrateNum>, cnum: CrateNum) {
141 if !deps.contains(&cnum) {
142 let data = self.get_crate_data(cnum);
143 for &dep in data.dependencies().iter() {
145 self.push_dependencies_in_postorder(deps, dep);
153 crate fn crate_dependencies_in_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
154 let mut deps = Vec::new();
155 if cnum == LOCAL_CRATE {
156 self.iter_crate_data(|cnum, _| self.push_dependencies_in_postorder(&mut deps, cnum));
158 self.push_dependencies_in_postorder(&mut deps, cnum);
163 fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
164 let mut deps = self.crate_dependencies_in_postorder(cnum);
169 crate fn injected_panic_runtime(&self) -> Option<CrateNum> {
170 self.injected_panic_runtime
173 crate fn allocator_kind(&self) -> Option<AllocatorKind> {
177 crate fn has_global_allocator(&self) -> bool {
178 self.has_global_allocator
182 impl<'a> CrateLoader<'a> {
185 metadata_loader: &'a MetadataLoaderDyn,
186 local_crate_name: &str,
191 local_crate_name: Symbol::intern(local_crate_name),
193 // We add an empty entry for LOCAL_CRATE (which maps to zero) in
194 // order to make array indices in `metas` match with the
195 // corresponding `CrateNum`. This first entry will always remain
197 metas: IndexVec::from_elem_n(None, 1),
198 injected_panic_runtime: None,
199 allocator_kind: None,
200 has_global_allocator: false,
205 pub fn cstore(&self) -> &CStore {
209 pub fn into_cstore(self) -> CStore {
213 fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
215 self.cstore.iter_crate_data(|cnum, data| {
216 if data.name() != name {
221 Some(hash) if hash == data.hash() => {
229 // When the hash is None we're dealing with a top-level dependency
230 // in which case we may have a specification on the command line for
231 // this library. Even though an upstream library may have loaded
232 // something of the same name, we have to make sure it was loaded
233 // from the exact same location as well.
235 // We're also sure to compare *paths*, not actual byte slices. The
236 // `source` stores paths which are normalized which may be different
237 // from the strings on the command line.
238 let source = self.cstore.get_crate_data(cnum).cdata.source();
239 if let Some(entry) = self.sess.opts.externs.get(&name.as_str()) {
240 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
241 if let Some(mut files) = entry.files() {
243 let l = fs::canonicalize(l).ok();
244 source.dylib.as_ref().map(|p| &p.0) == l.as_ref()
245 || source.rlib.as_ref().map(|p| &p.0) == l.as_ref()
253 // Alright, so we've gotten this far which means that `data` has the
254 // right name, we don't have a hash, and we don't have a --extern
255 // pointing for ourselves. We're still not quite yet done because we
256 // have to make sure that this crate was found in the crate lookup
257 // path (this is a top-level dependency) as we don't want to
258 // implicitly load anything inside the dependency lookup path.
259 let prev_kind = source
262 .or(source.rlib.as_ref())
263 .or(source.rmeta.as_ref())
264 .expect("No sources for crate")
266 if kind.matches(prev_kind) {
273 fn verify_no_symbol_conflicts(&self, span: Span, root: &CrateRoot<'_>) {
274 // Check for (potential) conflicts with the local crate
275 if self.local_crate_name == root.name()
276 && self.sess.local_crate_disambiguator() == root.disambiguator()
282 "the current crate is indistinguishable from one of its \
283 dependencies: it has the same crate-name `{}` and was \
284 compiled with the same `-C metadata` arguments. This \
285 will result in symbol conflicts between the two.",
291 // Check for conflicts with any crate loaded so far
292 self.cstore.iter_crate_data(|_, other| {
293 if other.name() == root.name() && // same crate-name
294 other.disambiguator() == root.disambiguator() && // same crate-disambiguator
295 other.hash() != root.hash()
302 "found two different crates with name `{}` that are \
303 not distinguished by differing `-C metadata`. This \
304 will result in symbol conflicts between the two.",
314 host_lib: Option<Library>,
315 root: Option<&CratePaths>,
321 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
323 let Library { source, metadata } = lib;
324 let crate_root = metadata.get_root();
325 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
326 self.verify_no_symbol_conflicts(span, &crate_root);
329 self.sess.opts.externs.get(&name.as_str()).map(|e| e.is_private_dep).unwrap_or(false);
331 info!("register crate `{}` (private_dep = {})", crate_root.name(), private_dep);
333 // Claim this crate number and cache it
334 let cnum = self.cstore.alloc_new_crate_num();
336 // Maintain a reference to the top most crate.
337 // Stash paths for top-most crate locally if necessary.
339 let root = if let Some(root) = root {
342 crate_paths = CratePaths::new(crate_root.name(), source.clone());
346 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, span, dep_kind);
348 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
350 let (dlsym_source, dlsym_root) = match &host_lib {
351 Some(host_lib) => (&host_lib.source, {
352 temp_root = host_lib.metadata.get_root();
355 None => (&source, &crate_root),
357 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
358 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.disambiguator(), span))
363 self.cstore.set_crate_data(
382 fn load_proc_macro<'b>(
384 locator: &mut CrateLocator<'b>,
386 ) -> Option<(LoadResult, Option<Library>)>
390 // Use a new crate locator so trying to load a proc macro doesn't affect the error
392 let mut proc_macro_locator = locator.clone();
394 // Try to load a proc macro
395 proc_macro_locator.is_proc_macro = Some(true);
397 // Load the proc macro crate for the target
398 let (locator, target_result) = if self.sess.opts.debugging_opts.dual_proc_macros {
399 proc_macro_locator.reset();
400 let result = match self.load(&mut proc_macro_locator)? {
401 LoadResult::Previous(cnum) => return Some((LoadResult::Previous(cnum), None)),
402 LoadResult::Loaded(library) => Some(LoadResult::Loaded(library)),
404 locator.hash = locator.host_hash;
405 // Use the locator when looking for the host proc macro crate, as that is required
406 // so we want it to affect the error message
409 (&mut proc_macro_locator, None)
412 // Load the proc macro crate for the host
415 locator.is_proc_macro = Some(true);
416 locator.target = &self.sess.host;
417 locator.triple = TargetTriple::from_triple(config::host_triple());
418 locator.filesearch = self.sess.host_filesearch(path_kind);
420 let host_result = self.load(locator)?;
422 Some(if self.sess.opts.debugging_opts.dual_proc_macros {
423 let host_result = match host_result {
424 LoadResult::Previous(..) => {
425 panic!("host and target proc macros must be loaded in lock-step")
427 LoadResult::Loaded(library) => library,
429 (target_result.unwrap(), Some(host_result))
435 fn resolve_crate<'b>(
440 dep: Option<(&'b CratePaths, &'b CrateDep)>,
442 self.maybe_resolve_crate(name, span, dep_kind, dep).unwrap_or_else(|err| err.report())
445 fn maybe_resolve_crate<'b>(
449 mut dep_kind: DepKind,
450 dep: Option<(&'b CratePaths, &'b CrateDep)>,
451 ) -> Result<CrateNum, LoadError<'b>> {
452 info!("resolving crate `{}`", name);
453 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
454 Some((root, dep)) => (
458 Some(&dep.extra_filename[..]),
459 PathKind::Dependency,
461 None => (None, None, None, None, PathKind::Crate),
463 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
464 (LoadResult::Previous(cnum), None)
466 info!("falling back to a load");
467 let mut locator = CrateLocator::new(
469 self.metadata_loader,
478 Some(false), // is_proc_macro
481 self.load(&mut locator)
484 dep_kind = DepKind::MacrosOnly;
485 self.load_proc_macro(&mut locator, path_kind)
487 .ok_or_else(move || LoadError::LocatorError(locator))?
491 (LoadResult::Previous(cnum), None) => {
492 let data = self.cstore.get_crate_data(cnum);
493 if data.is_proc_macro_crate() {
494 dep_kind = DepKind::MacrosOnly;
496 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
499 (LoadResult::Loaded(library), host_library) => {
500 Ok(self.register_crate(host_library, root, span, library, dep_kind, name))
506 fn load(&self, locator: &mut CrateLocator<'_>) -> Option<LoadResult> {
507 let library = locator.maybe_load_library_crate()?;
509 // In the case that we're loading a crate, but not matching
510 // against a hash, we could load a crate which has the same hash
511 // as an already loaded crate. If this is the case prevent
512 // duplicates by just using the first crate.
514 // Note that we only do this for target triple crates, though, as we
515 // don't want to match a host crate against an equivalent target one
517 let root = library.metadata.get_root();
518 if locator.triple == self.sess.opts.target_triple {
519 let mut result = LoadResult::Loaded(library);
520 self.cstore.iter_crate_data(|cnum, data| {
521 if data.name() == root.name() && root.hash() == data.hash() {
522 assert!(locator.hash.is_none());
523 info!("load success, going to previous cnum: {}", cnum);
524 result = LoadResult::Previous(cnum);
529 Some(LoadResult::Loaded(library))
533 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
534 let cmeta = self.cstore.get_crate_data(cnum);
535 if cmeta.update_extern_crate(extern_crate) {
536 // Propagate the extern crate info to dependencies if it was updated.
537 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
538 for &dep_cnum in cmeta.dependencies().iter() {
539 self.update_extern_crate(dep_cnum, extern_crate);
544 // Go through the crate metadata and load any crates that it references
545 fn resolve_crate_deps(
548 crate_root: &CrateRoot<'_>,
549 metadata: &MetadataBlob,
554 debug!("resolving deps of external crate");
555 if crate_root.is_proc_macro_crate() {
556 return CrateNumMap::new();
559 // The map from crate numbers in the crate we're resolving to local crate numbers.
560 // We map 0 and all other holes in the map to our parent crate. The "additional"
561 // self-dependencies should be harmless.
562 std::iter::once(krate)
563 .chain(crate_root.decode_crate_deps(metadata).map(|dep| {
565 "resolving dep crate {} hash: `{}` extra filename: `{}`",
566 dep.name, dep.hash, dep.extra_filename
568 let dep_kind = match dep_kind {
569 DepKind::MacrosOnly => DepKind::MacrosOnly,
572 self.resolve_crate(dep.name, span, dep_kind, Some((root, &dep)))
577 fn dlsym_proc_macros(
580 disambiguator: CrateDisambiguator,
582 ) -> &'static [ProcMacro] {
583 use crate::dynamic_lib::DynamicLibrary;
586 // Make sure the path contains a / or the linker will search for it.
587 let path = env::current_dir().unwrap().join(path);
588 let lib = match DynamicLibrary::open(Some(&path)) {
590 Err(err) => self.sess.span_fatal(span, &err),
593 let sym = self.sess.generate_proc_macro_decls_symbol(disambiguator);
595 let sym = match lib.symbol(&sym) {
597 Err(err) => self.sess.span_fatal(span, &err),
599 *(sym as *const &[ProcMacro])
602 // Intentionally leak the dynamic library. We can't ever unload it
603 // since the library can make things that will live arbitrarily long.
604 std::mem::forget(lib);
609 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
610 // If we're only compiling an rlib, then there's no need to select a
611 // panic runtime, so we just skip this section entirely.
613 self.sess.crate_types.borrow().iter().any(|ct| *ct != config::CrateType::Rlib);
615 info!("panic runtime injection skipped, only generating rlib");
619 // If we need a panic runtime, we try to find an existing one here. At
620 // the same time we perform some general validation of the DAG we've got
621 // going such as ensuring everything has a compatible panic strategy.
623 // The logic for finding the panic runtime here is pretty much the same
624 // as the allocator case with the only addition that the panic strategy
625 // compilation mode also comes into play.
626 let desired_strategy = self.sess.panic_strategy();
627 let mut runtime_found = false;
628 let mut needs_panic_runtime = attr::contains_name(&krate.attrs, sym::needs_panic_runtime);
630 self.cstore.iter_crate_data(|cnum, data| {
631 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
632 if data.is_panic_runtime() {
633 // Inject a dependency from all #![needs_panic_runtime] to this
634 // #![panic_runtime] crate.
635 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
636 data.needs_panic_runtime()
638 runtime_found = runtime_found || data.dep_kind() == DepKind::Explicit;
642 // If an explicitly linked and matching panic runtime was found, or if
643 // we just don't need one at all, then we're done here and there's
644 // nothing else to do.
645 if !needs_panic_runtime || runtime_found {
649 // By this point we know that we (a) need a panic runtime and (b) no
650 // panic runtime was explicitly linked. Here we just load an appropriate
651 // default runtime for our panic strategy and then inject the
654 // We may resolve to an already loaded crate (as the crate may not have
655 // been explicitly linked prior to this) and we may re-inject
656 // dependencies again, but both of those situations are fine.
658 // Also note that we have yet to perform validation of the crate graph
659 // in terms of everyone has a compatible panic runtime format, that's
660 // performed later as part of the `dependency_format` module.
661 let name = match desired_strategy {
662 PanicStrategy::Unwind => Symbol::intern("panic_unwind"),
663 PanicStrategy::Abort => Symbol::intern("panic_abort"),
665 info!("panic runtime not found -- loading {}", name);
667 let cnum = self.resolve_crate(name, DUMMY_SP, DepKind::Implicit, None);
668 let data = self.cstore.get_crate_data(cnum);
670 // Sanity check the loaded crate to ensure it is indeed a panic runtime
671 // and the panic strategy is indeed what we thought it was.
672 if !data.is_panic_runtime() {
673 self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
675 if data.panic_strategy() != desired_strategy {
676 self.sess.err(&format!(
677 "the crate `{}` does not have the panic \
680 desired_strategy.desc()
684 self.cstore.injected_panic_runtime = Some(cnum);
685 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
688 fn inject_profiler_runtime(&mut self) {
689 if self.sess.opts.debugging_opts.profile || self.sess.opts.cg.profile_generate.enabled() {
690 info!("loading profiler");
692 let name = Symbol::intern("profiler_builtins");
693 let cnum = self.resolve_crate(name, DUMMY_SP, DepKind::Implicit, None);
694 let data = self.cstore.get_crate_data(cnum);
696 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
697 if !data.is_profiler_runtime() {
698 self.sess.err("the crate `profiler_builtins` is not a profiler runtime");
703 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
704 self.cstore.has_global_allocator = match &*global_allocator_spans(krate) {
705 [span1, span2, ..] => {
707 .struct_span_err(*span2, "cannot define multiple global allocators")
708 .span_label(*span2, "cannot define a new global allocator")
709 .span_label(*span1, "previous global allocator defined here")
713 spans => !spans.is_empty(),
716 // Check to see if we actually need an allocator. This desire comes
717 // about through the `#![needs_allocator]` attribute and is typically
718 // written down in liballoc.
719 let mut needs_allocator = attr::contains_name(&krate.attrs, sym::needs_allocator);
720 self.cstore.iter_crate_data(|_, data| {
721 needs_allocator = needs_allocator || data.needs_allocator();
723 if !needs_allocator {
727 // At this point we've determined that we need an allocator. Let's see
728 // if our compilation session actually needs an allocator based on what
730 let all_rlib = self.sess.crate_types.borrow().iter().all(|ct| match *ct {
731 config::CrateType::Rlib => true,
738 // Ok, we need an allocator. Not only that but we're actually going to
739 // create an artifact that needs one linked in. Let's go find the one
740 // that we're going to link in.
742 // First up we check for global allocators. Look at the crate graph here
743 // and see what's a global allocator, including if we ourselves are a
745 let mut global_allocator =
746 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
747 self.cstore.iter_crate_data(|_, data| {
748 if !data.has_global_allocator() {
751 match global_allocator {
752 Some(other_crate) => {
753 self.sess.err(&format!(
754 "the `#[global_allocator]` in {} \
755 conflicts with global \
761 None => global_allocator = Some(data.name()),
764 if global_allocator.is_some() {
765 self.cstore.allocator_kind = Some(AllocatorKind::Global);
769 // Ok we haven't found a global allocator but we still need an
770 // allocator. At this point our allocator request is typically fulfilled
771 // by the standard library, denoted by the `#![default_lib_allocator]`
773 let mut has_default = attr::contains_name(&krate.attrs, sym::default_lib_allocator);
774 self.cstore.iter_crate_data(|_, data| {
775 if data.has_default_lib_allocator() {
782 "no global memory allocator found but one is \
783 required; link to std or \
784 add `#[global_allocator]` to a static item \
785 that implements the GlobalAlloc trait.",
788 self.cstore.allocator_kind = Some(AllocatorKind::Default);
791 fn inject_dependency_if(
795 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
797 // don't perform this validation if the session has errors, as one of
798 // those errors may indicate a circular dependency which could cause
799 // this to stack overflow.
800 if self.sess.has_errors() {
804 // Before we inject any dependencies, make sure we don't inject a
805 // circular dependency by validating that this crate doesn't
806 // transitively depend on any crates satisfying `needs_dep`.
807 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
808 let data = self.cstore.get_crate_data(dep);
809 if needs_dep(&data) {
810 self.sess.err(&format!(
811 "the crate `{}` cannot depend \
812 on a crate that needs {}, but \
814 self.cstore.get_crate_data(krate).name(),
821 // All crates satisfying `needs_dep` do not explicitly depend on the
822 // crate provided for this compile, but in order for this compilation to
823 // be successfully linked we need to inject a dependency (to order the
824 // crates on the command line correctly).
825 self.cstore.iter_crate_data(|cnum, data| {
826 if !needs_dep(data) {
830 info!("injecting a dep from {} to {}", cnum, krate);
831 data.add_dependency(krate);
835 pub fn postprocess(&mut self, krate: &ast::Crate) {
836 self.inject_profiler_runtime();
837 self.inject_allocator_crate(krate);
838 self.inject_panic_runtime(krate);
840 if log_enabled!(log::Level::Info) {
841 dump_crates(&self.cstore);
845 pub fn process_extern_crate(
848 definitions: &Definitions,
851 ast::ItemKind::ExternCrate(orig_name) => {
853 "resolving extern crate stmt. ident: {} orig_name: {:?}",
854 item.ident, orig_name
856 let name = match orig_name {
858 validate_crate_name(Some(self.sess), &orig_name.as_str(), Some(item.span));
861 None => item.ident.name,
863 let dep_kind = if attr::contains_name(&item.attrs, sym::no_link) {
869 let cnum = self.resolve_crate(name, item.span, dep_kind, None);
871 let def_id = definitions.opt_local_def_id(item.id).unwrap();
872 let path_len = definitions.def_path(def_id).data.len();
873 self.update_extern_crate(
876 src: ExternCrateSource::Extern(def_id.to_def_id()),
879 dependency_of: LOCAL_CRATE,
888 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> CrateNum {
889 let cnum = self.resolve_crate(name, span, DepKind::Explicit, None);
891 self.update_extern_crate(
894 src: ExternCrateSource::Path,
896 // to have the least priority in `update_extern_crate`
897 path_len: usize::max_value(),
898 dependency_of: LOCAL_CRATE,
905 pub fn maybe_process_path_extern(&mut self, name: Symbol, span: Span) -> Option<CrateNum> {
906 self.maybe_resolve_crate(name, span, DepKind::Explicit, None).ok()