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::hir::map::Definitions;
7 use rustc::middle::cstore::DepKind;
8 use rustc::middle::cstore::{CrateSource, ExternCrate, ExternCrateSource, MetadataLoaderDyn};
9 use rustc::session::config;
10 use rustc::session::search_paths::PathKind;
11 use rustc::session::{CrateDisambiguator, Session};
12 use rustc::ty::TyCtxt;
13 use rustc_data_structures::svh::Svh;
14 use rustc_data_structures::sync::Lrc;
15 use rustc_hir::def_id::CrateNum;
16 use rustc_hir::def_id::LOCAL_CRATE;
17 use rustc_index::vec::IndexVec;
18 use rustc_target::spec::{PanicStrategy, TargetTriple};
23 use errors::struct_span_err;
24 use log::{debug, info, log_enabled};
25 use proc_macro::bridge::client::ProcMacro;
26 use rustc_expand::base::SyntaxExtension;
27 use rustc_span::edition::Edition;
28 use rustc_span::symbol::{sym, Symbol};
29 use rustc_span::{Span, DUMMY_SP};
32 use syntax::expand::allocator::{global_allocator_spans, AllocatorKind};
34 use rustc_error_codes::*;
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,
56 pub enum LoadedMacro {
57 MacroDef(ast::Item, Edition),
58 ProcMacro(SyntaxExtension),
61 crate struct Library {
62 pub source: CrateSource,
63 pub metadata: MetadataBlob,
72 LocatorError(CrateLocator<'a>),
75 impl<'a> LoadError<'a> {
76 fn report(self) -> ! {
78 LoadError::LocatorError(locator) => locator.report_errs(),
83 fn dump_crates(cstore: &CStore) {
84 info!("resolved crates:");
85 cstore.iter_crate_data(|cnum, data| {
86 info!(" name: {}", data.name());
87 info!(" cnum: {}", cnum);
88 info!(" hash: {}", data.hash());
89 info!(" reqd: {:?}", data.dep_kind());
90 let CrateSource { dylib, rlib, rmeta } = data.source();
91 dylib.as_ref().map(|dl| info!(" dylib: {}", dl.0.display()));
92 rlib.as_ref().map(|rl| info!(" rlib: {}", rl.0.display()));
93 rmeta.as_ref().map(|rl| info!(" rmeta: {}", rl.0.display()));
98 crate fn from_tcx(tcx: TyCtxt<'_>) -> &CStore {
99 tcx.cstore_as_any().downcast_ref::<CStore>().expect("`tcx.cstore` is not a `CStore`")
102 fn alloc_new_crate_num(&mut self) -> CrateNum {
103 self.metas.push(None);
104 CrateNum::new(self.metas.len() - 1)
107 crate fn get_crate_data(&self, cnum: CrateNum) -> &CrateMetadata {
110 .unwrap_or_else(|| panic!("Failed to get crate data for {:?}", cnum))
113 fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
114 assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
115 self.metas[cnum] = Some(Lrc::new(data));
118 crate fn iter_crate_data(&self, mut f: impl FnMut(CrateNum, &CrateMetadata)) {
119 for (cnum, data) in self.metas.iter_enumerated() {
120 if let Some(data) = data {
126 fn push_dependencies_in_postorder(&self, deps: &mut Vec<CrateNum>, cnum: CrateNum) {
127 if !deps.contains(&cnum) {
128 let data = self.get_crate_data(cnum);
129 for &dep in data.dependencies().iter() {
131 self.push_dependencies_in_postorder(deps, dep);
139 crate fn crate_dependencies_in_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
140 let mut deps = Vec::new();
141 if cnum == LOCAL_CRATE {
142 self.iter_crate_data(|cnum, _| self.push_dependencies_in_postorder(&mut deps, cnum));
144 self.push_dependencies_in_postorder(&mut deps, cnum);
149 fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
150 let mut deps = self.crate_dependencies_in_postorder(cnum);
155 crate fn injected_panic_runtime(&self) -> Option<CrateNum> {
156 self.injected_panic_runtime
159 crate fn allocator_kind(&self) -> Option<AllocatorKind> {
163 crate fn has_global_allocator(&self) -> bool {
164 self.has_global_allocator
168 impl<'a> CrateLoader<'a> {
171 metadata_loader: &'a MetadataLoaderDyn,
172 local_crate_name: &str,
177 local_crate_name: Symbol::intern(local_crate_name),
179 // We add an empty entry for LOCAL_CRATE (which maps to zero) in
180 // order to make array indices in `metas` match with the
181 // corresponding `CrateNum`. This first entry will always remain
183 metas: IndexVec::from_elem_n(None, 1),
184 injected_panic_runtime: None,
185 allocator_kind: None,
186 has_global_allocator: false,
191 pub fn cstore(&self) -> &CStore {
195 pub fn into_cstore(self) -> CStore {
199 fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
201 self.cstore.iter_crate_data(|cnum, data| {
202 if data.name() != name {
207 Some(hash) if hash == data.hash() => {
215 // When the hash is None we're dealing with a top-level dependency
216 // in which case we may have a specification on the command line for
217 // this library. Even though an upstream library may have loaded
218 // something of the same name, we have to make sure it was loaded
219 // from the exact same location as well.
221 // We're also sure to compare *paths*, not actual byte slices. The
222 // `source` stores paths which are normalized which may be different
223 // from the strings on the command line.
224 let source = self.cstore.get_crate_data(cnum).source();
225 if let Some(entry) = self.sess.opts.externs.get(&name.as_str()) {
226 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
227 if let Some(mut files) = entry.files() {
229 let l = fs::canonicalize(l).ok();
230 source.dylib.as_ref().map(|p| &p.0) == l.as_ref()
231 || source.rlib.as_ref().map(|p| &p.0) == l.as_ref()
239 // Alright, so we've gotten this far which means that `data` has the
240 // right name, we don't have a hash, and we don't have a --extern
241 // pointing for ourselves. We're still not quite yet done because we
242 // have to make sure that this crate was found in the crate lookup
243 // path (this is a top-level dependency) as we don't want to
244 // implicitly load anything inside the dependency lookup path.
245 let prev_kind = source
248 .or(source.rlib.as_ref())
249 .or(source.rmeta.as_ref())
250 .expect("No sources for crate")
252 if kind.matches(prev_kind) {
259 fn verify_no_symbol_conflicts(&self, span: Span, root: &CrateRoot<'_>) {
260 // Check for (potential) conflicts with the local crate
261 if self.local_crate_name == root.name()
262 && self.sess.local_crate_disambiguator() == root.disambiguator()
268 "the current crate is indistinguishable from one of its \
269 dependencies: it has the same crate-name `{}` and was \
270 compiled with the same `-C metadata` arguments. This \
271 will result in symbol conflicts between the two.",
277 // Check for conflicts with any crate loaded so far
278 self.cstore.iter_crate_data(|_, other| {
279 if other.name() == root.name() && // same crate-name
280 other.disambiguator() == root.disambiguator() && // same crate-disambiguator
281 other.hash() != root.hash()
288 "found two different crates with name `{}` that are \
289 not distinguished by differing `-C metadata`. This \
290 will result in symbol conflicts between the two.",
300 host_lib: Option<Library>,
301 root: Option<&CratePaths>,
307 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
309 let Library { source, metadata } = lib;
310 let crate_root = metadata.get_root();
311 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
312 self.verify_no_symbol_conflicts(span, &crate_root);
315 self.sess.opts.externs.get(&name.as_str()).map(|e| e.is_private_dep).unwrap_or(false);
317 info!("register crate `{}` (private_dep = {})", crate_root.name(), private_dep);
319 // Claim this crate number and cache it
320 let cnum = self.cstore.alloc_new_crate_num();
322 // Maintain a reference to the top most crate.
323 // Stash paths for top-most crate locally if necessary.
325 let root = if let Some(root) = root {
328 crate_paths = CratePaths::new(crate_root.name(), source.clone());
332 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, span, dep_kind);
334 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
336 let (dlsym_source, dlsym_root) = match &host_lib {
337 Some(host_lib) => (&host_lib.source, {
338 temp_root = host_lib.metadata.get_root();
341 None => (&source, &crate_root),
343 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
344 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.disambiguator(), span))
349 self.cstore.set_crate_data(
368 fn load_proc_macro<'b>(
370 locator: &mut CrateLocator<'b>,
372 ) -> Option<(LoadResult, Option<Library>)>
376 // Use a new crate locator so trying to load a proc macro doesn't affect the error
378 let mut proc_macro_locator = locator.clone();
380 // Try to load a proc macro
381 proc_macro_locator.is_proc_macro = Some(true);
383 // Load the proc macro crate for the target
384 let (locator, target_result) = if self.sess.opts.debugging_opts.dual_proc_macros {
385 proc_macro_locator.reset();
386 let result = match self.load(&mut proc_macro_locator)? {
387 LoadResult::Previous(cnum) => return Some((LoadResult::Previous(cnum), None)),
388 LoadResult::Loaded(library) => Some(LoadResult::Loaded(library)),
390 locator.hash = locator.host_hash;
391 // Use the locator when looking for the host proc macro crate, as that is required
392 // so we want it to affect the error message
395 (&mut proc_macro_locator, None)
398 // Load the proc macro crate for the host
401 locator.is_proc_macro = Some(true);
402 locator.target = &self.sess.host;
403 locator.triple = TargetTriple::from_triple(config::host_triple());
404 locator.filesearch = self.sess.host_filesearch(path_kind);
406 let host_result = self.load(locator)?;
408 Some(if self.sess.opts.debugging_opts.dual_proc_macros {
409 let host_result = match host_result {
410 LoadResult::Previous(..) => {
411 panic!("host and target proc macros must be loaded in lock-step")
413 LoadResult::Loaded(library) => library,
415 (target_result.unwrap(), Some(host_result))
421 fn resolve_crate<'b>(
426 dep: Option<(&'b CratePaths, &'b CrateDep)>,
428 self.maybe_resolve_crate(name, span, dep_kind, dep).unwrap_or_else(|err| err.report())
431 fn maybe_resolve_crate<'b>(
435 mut dep_kind: DepKind,
436 dep: Option<(&'b CratePaths, &'b CrateDep)>,
437 ) -> Result<CrateNum, LoadError<'b>> {
438 info!("resolving crate `{}`", name);
439 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
440 Some((root, dep)) => (
444 Some(&dep.extra_filename[..]),
445 PathKind::Dependency,
447 None => (None, None, None, None, PathKind::Crate),
449 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
450 (LoadResult::Previous(cnum), None)
452 info!("falling back to a load");
453 let mut locator = CrateLocator::new(
455 self.metadata_loader,
464 Some(false), // is_proc_macro
467 self.load(&mut locator)
470 dep_kind = DepKind::UnexportedMacrosOnly;
471 self.load_proc_macro(&mut locator, path_kind)
473 .ok_or_else(move || LoadError::LocatorError(locator))?
477 (LoadResult::Previous(cnum), None) => {
478 let data = self.cstore.get_crate_data(cnum);
479 if data.is_proc_macro_crate() {
480 dep_kind = DepKind::UnexportedMacrosOnly;
482 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
485 (LoadResult::Loaded(library), host_library) => {
486 Ok(self.register_crate(host_library, root, span, library, dep_kind, name))
492 fn load(&self, locator: &mut CrateLocator<'_>) -> Option<LoadResult> {
493 let library = locator.maybe_load_library_crate()?;
495 // In the case that we're loading a crate, but not matching
496 // against a hash, we could load a crate which has the same hash
497 // as an already loaded crate. If this is the case prevent
498 // duplicates by just using the first crate.
500 // Note that we only do this for target triple crates, though, as we
501 // don't want to match a host crate against an equivalent target one
503 let root = library.metadata.get_root();
504 if locator.triple == self.sess.opts.target_triple {
505 let mut result = LoadResult::Loaded(library);
506 self.cstore.iter_crate_data(|cnum, data| {
507 if data.name() == root.name() && root.hash() == data.hash() {
508 assert!(locator.hash.is_none());
509 info!("load success, going to previous cnum: {}", cnum);
510 result = LoadResult::Previous(cnum);
515 Some(LoadResult::Loaded(library))
519 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
520 let cmeta = self.cstore.get_crate_data(cnum);
521 if cmeta.update_extern_crate(extern_crate) {
522 // Propagate the extern crate info to dependencies if it was updated.
523 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
524 for &dep_cnum in cmeta.dependencies().iter() {
525 self.update_extern_crate(dep_cnum, extern_crate);
530 // Go through the crate metadata and load any crates that it references
531 fn resolve_crate_deps(
534 crate_root: &CrateRoot<'_>,
535 metadata: &MetadataBlob,
540 debug!("resolving deps of external crate");
541 if crate_root.is_proc_macro_crate() {
542 return CrateNumMap::new();
545 // The map from crate numbers in the crate we're resolving to local crate numbers.
546 // We map 0 and all other holes in the map to our parent crate. The "additional"
547 // self-dependencies should be harmless.
548 std::iter::once(krate)
549 .chain(crate_root.decode_crate_deps(metadata).map(|dep| {
551 "resolving dep crate {} hash: `{}` extra filename: `{}`",
552 dep.name, dep.hash, dep.extra_filename
554 if dep.kind == DepKind::UnexportedMacrosOnly {
557 let dep_kind = match dep_kind {
558 DepKind::MacrosOnly => DepKind::MacrosOnly,
561 self.resolve_crate(dep.name, span, dep_kind, Some((root, &dep)))
566 fn dlsym_proc_macros(
569 disambiguator: CrateDisambiguator,
571 ) -> &'static [ProcMacro] {
572 use crate::dynamic_lib::DynamicLibrary;
575 // Make sure the path contains a / or the linker will search for it.
576 let path = env::current_dir().unwrap().join(path);
577 let lib = match DynamicLibrary::open(Some(&path)) {
579 Err(err) => self.sess.span_fatal(span, &err),
582 let sym = self.sess.generate_proc_macro_decls_symbol(disambiguator);
584 let sym = match lib.symbol(&sym) {
586 Err(err) => self.sess.span_fatal(span, &err),
588 *(sym as *const &[ProcMacro])
591 // Intentionally leak the dynamic library. We can't ever unload it
592 // since the library can make things that will live arbitrarily long.
593 std::mem::forget(lib);
598 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
599 // If we're only compiling an rlib, then there's no need to select a
600 // panic runtime, so we just skip this section entirely.
602 self.sess.crate_types.borrow().iter().any(|ct| *ct != config::CrateType::Rlib);
604 info!("panic runtime injection skipped, only generating rlib");
608 // If we need a panic runtime, we try to find an existing one here. At
609 // the same time we perform some general validation of the DAG we've got
610 // going such as ensuring everything has a compatible panic strategy.
612 // The logic for finding the panic runtime here is pretty much the same
613 // as the allocator case with the only addition that the panic strategy
614 // compilation mode also comes into play.
615 let desired_strategy = self.sess.panic_strategy();
616 let mut runtime_found = false;
617 let mut needs_panic_runtime = attr::contains_name(&krate.attrs, sym::needs_panic_runtime);
619 self.cstore.iter_crate_data(|cnum, data| {
620 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
621 if data.is_panic_runtime() {
622 // Inject a dependency from all #![needs_panic_runtime] to this
623 // #![panic_runtime] crate.
624 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
625 data.needs_panic_runtime()
627 runtime_found = runtime_found || data.dep_kind() == DepKind::Explicit;
631 // If an explicitly linked and matching panic runtime was found, or if
632 // we just don't need one at all, then we're done here and there's
633 // nothing else to do.
634 if !needs_panic_runtime || runtime_found {
638 // By this point we know that we (a) need a panic runtime and (b) no
639 // panic runtime was explicitly linked. Here we just load an appropriate
640 // default runtime for our panic strategy and then inject the
643 // We may resolve to an already loaded crate (as the crate may not have
644 // been explicitly linked prior to this) and we may re-inject
645 // dependencies again, but both of those situations are fine.
647 // Also note that we have yet to perform validation of the crate graph
648 // in terms of everyone has a compatible panic runtime format, that's
649 // performed later as part of the `dependency_format` module.
650 let name = match desired_strategy {
651 PanicStrategy::Unwind => Symbol::intern("panic_unwind"),
652 PanicStrategy::Abort => Symbol::intern("panic_abort"),
654 info!("panic runtime not found -- loading {}", name);
656 let cnum = self.resolve_crate(name, DUMMY_SP, DepKind::Implicit, None);
657 let data = self.cstore.get_crate_data(cnum);
659 // Sanity check the loaded crate to ensure it is indeed a panic runtime
660 // and the panic strategy is indeed what we thought it was.
661 if !data.is_panic_runtime() {
662 self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
664 if data.panic_strategy() != desired_strategy {
665 self.sess.err(&format!(
666 "the crate `{}` does not have the panic \
669 desired_strategy.desc()
673 self.cstore.injected_panic_runtime = Some(cnum);
674 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
677 fn inject_profiler_runtime(&mut self) {
678 if self.sess.opts.debugging_opts.profile || self.sess.opts.cg.profile_generate.enabled() {
679 info!("loading profiler");
681 let name = Symbol::intern("profiler_builtins");
682 let cnum = self.resolve_crate(name, DUMMY_SP, DepKind::Implicit, None);
683 let data = self.cstore.get_crate_data(cnum);
685 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
686 if !data.is_profiler_runtime() {
687 self.sess.err(&format!(
688 "the crate `profiler_builtins` is not \
695 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
696 self.cstore.has_global_allocator = match &*global_allocator_spans(krate) {
697 [span1, span2, ..] => {
699 .struct_span_err(*span2, "cannot define multiple global allocators")
700 .span_label(*span2, "cannot define a new global allocator")
701 .span_label(*span1, "previous global allocator is defined here")
705 spans => !spans.is_empty(),
708 // Check to see if we actually need an allocator. This desire comes
709 // about through the `#![needs_allocator]` attribute and is typically
710 // written down in liballoc.
711 let mut needs_allocator = attr::contains_name(&krate.attrs, sym::needs_allocator);
712 self.cstore.iter_crate_data(|_, data| {
713 needs_allocator = needs_allocator || data.needs_allocator();
715 if !needs_allocator {
719 // At this point we've determined that we need an allocator. Let's see
720 // if our compilation session actually needs an allocator based on what
722 let all_rlib = self.sess.crate_types.borrow().iter().all(|ct| match *ct {
723 config::CrateType::Rlib => true,
730 // Ok, we need an allocator. Not only that but we're actually going to
731 // create an artifact that needs one linked in. Let's go find the one
732 // that we're going to link in.
734 // First up we check for global allocators. Look at the crate graph here
735 // and see what's a global allocator, including if we ourselves are a
737 let mut global_allocator =
738 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
739 self.cstore.iter_crate_data(|_, data| {
740 if !data.has_global_allocator() {
743 match global_allocator {
744 Some(other_crate) => {
745 self.sess.err(&format!(
746 "the `#[global_allocator]` in {} \
747 conflicts with global \
753 None => global_allocator = Some(data.name()),
756 if global_allocator.is_some() {
757 self.cstore.allocator_kind = Some(AllocatorKind::Global);
761 // Ok we haven't found a global allocator but we still need an
762 // allocator. At this point our allocator request is typically fulfilled
763 // by the standard library, denoted by the `#![default_lib_allocator]`
765 let mut has_default = attr::contains_name(&krate.attrs, sym::default_lib_allocator);
766 self.cstore.iter_crate_data(|_, data| {
767 if data.has_default_lib_allocator() {
774 "no global memory allocator found but one is \
775 required; link to std or \
776 add `#[global_allocator]` to a static item \
777 that implements the GlobalAlloc trait.",
780 self.cstore.allocator_kind = Some(AllocatorKind::Default);
783 fn inject_dependency_if(
787 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
789 // don't perform this validation if the session has errors, as one of
790 // those errors may indicate a circular dependency which could cause
791 // this to stack overflow.
792 if self.sess.has_errors() {
796 // Before we inject any dependencies, make sure we don't inject a
797 // circular dependency by validating that this crate doesn't
798 // transitively depend on any crates satisfying `needs_dep`.
799 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
800 let data = self.cstore.get_crate_data(dep);
801 if needs_dep(&data) {
802 self.sess.err(&format!(
803 "the crate `{}` cannot depend \
804 on a crate that needs {}, but \
806 self.cstore.get_crate_data(krate).name(),
813 // All crates satisfying `needs_dep` do not explicitly depend on the
814 // crate provided for this compile, but in order for this compilation to
815 // be successfully linked we need to inject a dependency (to order the
816 // crates on the command line correctly).
817 self.cstore.iter_crate_data(|cnum, data| {
818 if !needs_dep(data) {
822 info!("injecting a dep from {} to {}", cnum, krate);
823 data.add_dependency(krate);
827 pub fn postprocess(&mut self, krate: &ast::Crate) {
828 self.inject_profiler_runtime();
829 self.inject_allocator_crate(krate);
830 self.inject_panic_runtime(krate);
832 if log_enabled!(log::Level::Info) {
833 dump_crates(&self.cstore);
837 pub fn process_extern_crate(
840 definitions: &Definitions,
843 ast::ItemKind::ExternCrate(orig_name) => {
845 "resolving extern crate stmt. ident: {} orig_name: {:?}",
846 item.ident, orig_name
848 let name = match orig_name {
850 crate::validate_crate_name(
857 None => item.ident.name,
859 let dep_kind = if attr::contains_name(&item.attrs, sym::no_link) {
860 DepKind::UnexportedMacrosOnly
865 let cnum = self.resolve_crate(name, item.span, dep_kind, None);
867 let def_id = definitions.opt_local_def_id(item.id).unwrap();
868 let path_len = definitions.def_path(def_id.index).data.len();
869 self.update_extern_crate(
872 src: ExternCrateSource::Extern(def_id),
875 dependency_of: LOCAL_CRATE,
884 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> CrateNum {
885 let cnum = self.resolve_crate(name, span, DepKind::Explicit, None);
887 self.update_extern_crate(
890 src: ExternCrateSource::Path,
892 // to have the least priority in `update_extern_crate`
893 path_len: usize::max_value(),
894 dependency_of: LOCAL_CRATE,
901 pub fn maybe_process_path_extern(&mut self, name: Symbol, span: Span) -> Option<CrateNum> {
902 self.maybe_resolve_crate(name, span, DepKind::Explicit, None).ok()