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;
15 use rustc_ast::expand::allocator::{global_allocator_spans, AllocatorKind};
16 use rustc_data_structures::svh::Svh;
17 use rustc_data_structures::sync::Lrc;
18 use rustc_errors::struct_span_err;
19 use rustc_expand::base::SyntaxExtension;
20 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
21 use rustc_index::vec::IndexVec;
22 use rustc_span::edition::Edition;
23 use rustc_span::symbol::{sym, Symbol};
24 use rustc_span::{Span, DUMMY_SP};
25 use rustc_target::spec::{PanicStrategy, TargetTriple};
27 use log::{debug, info, log_enabled};
28 use proc_macro::bridge::client::ProcMacro;
34 metas: IndexVec<CrateNum, Option<Lrc<CrateMetadata>>>,
35 injected_panic_runtime: Option<CrateNum>,
36 /// This crate needs an allocator and either provides it itself, or finds it in a dependency.
37 /// If the above is true, then this field denotes the kind of the found allocator.
38 allocator_kind: Option<AllocatorKind>,
39 /// This crate has a `#[global_allocator]` item.
40 has_global_allocator: bool,
43 pub struct CrateLoader<'a> {
44 // Immutable configuration.
46 metadata_loader: &'a MetadataLoaderDyn,
47 local_crate_name: Symbol,
52 pub enum LoadedMacro {
53 MacroDef(ast::Item, Edition),
54 ProcMacro(SyntaxExtension),
57 crate struct Library {
58 pub source: CrateSource,
59 pub metadata: MetadataBlob,
68 LocatorError(CrateLocator<'a>),
71 impl<'a> LoadError<'a> {
72 fn report(self) -> ! {
74 LoadError::LocatorError(locator) => locator.report_errs(),
79 /// A reference to `CrateMetadata` that can also give access to whole crate store when necessary.
80 #[derive(Clone, Copy)]
81 crate struct CrateMetadataRef<'a> {
82 pub cdata: &'a CrateMetadata,
83 pub cstore: &'a CStore,
86 impl std::ops::Deref for CrateMetadataRef<'_> {
87 type Target = CrateMetadata;
89 fn deref(&self) -> &Self::Target {
94 fn dump_crates(cstore: &CStore) {
95 info!("resolved crates:");
96 cstore.iter_crate_data(|cnum, data| {
97 info!(" name: {}", data.name());
98 info!(" cnum: {}", cnum);
99 info!(" hash: {}", data.hash());
100 info!(" reqd: {:?}", data.dep_kind());
101 let CrateSource { dylib, rlib, rmeta } = data.source();
102 dylib.as_ref().map(|dl| info!(" dylib: {}", dl.0.display()));
103 rlib.as_ref().map(|rl| info!(" rlib: {}", rl.0.display()));
104 rmeta.as_ref().map(|rl| info!(" rmeta: {}", rl.0.display()));
109 crate fn from_tcx(tcx: TyCtxt<'_>) -> &CStore {
110 tcx.cstore_as_any().downcast_ref::<CStore>().expect("`tcx.cstore` is not a `CStore`")
113 fn alloc_new_crate_num(&mut self) -> CrateNum {
114 self.metas.push(None);
115 CrateNum::new(self.metas.len() - 1)
118 crate fn get_crate_data(&self, cnum: CrateNum) -> CrateMetadataRef<'_> {
119 let cdata = self.metas[cnum]
121 .unwrap_or_else(|| panic!("Failed to get crate data for {:?}", cnum));
122 CrateMetadataRef { cdata, cstore: self }
125 fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
126 assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
127 self.metas[cnum] = Some(Lrc::new(data));
130 crate fn iter_crate_data(&self, mut f: impl FnMut(CrateNum, &CrateMetadata)) {
131 for (cnum, data) in self.metas.iter_enumerated() {
132 if let Some(data) = data {
138 fn push_dependencies_in_postorder(&self, deps: &mut Vec<CrateNum>, cnum: CrateNum) {
139 if !deps.contains(&cnum) {
140 let data = self.get_crate_data(cnum);
141 for &dep in data.dependencies().iter() {
143 self.push_dependencies_in_postorder(deps, dep);
151 crate fn crate_dependencies_in_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
152 let mut deps = Vec::new();
153 if cnum == LOCAL_CRATE {
154 self.iter_crate_data(|cnum, _| self.push_dependencies_in_postorder(&mut deps, cnum));
156 self.push_dependencies_in_postorder(&mut deps, cnum);
161 fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
162 let mut deps = self.crate_dependencies_in_postorder(cnum);
167 crate fn injected_panic_runtime(&self) -> Option<CrateNum> {
168 self.injected_panic_runtime
171 crate fn allocator_kind(&self) -> Option<AllocatorKind> {
175 crate fn has_global_allocator(&self) -> bool {
176 self.has_global_allocator
180 impl<'a> CrateLoader<'a> {
183 metadata_loader: &'a MetadataLoaderDyn,
184 local_crate_name: &str,
189 local_crate_name: Symbol::intern(local_crate_name),
191 // We add an empty entry for LOCAL_CRATE (which maps to zero) in
192 // order to make array indices in `metas` match with the
193 // corresponding `CrateNum`. This first entry will always remain
195 metas: IndexVec::from_elem_n(None, 1),
196 injected_panic_runtime: None,
197 allocator_kind: None,
198 has_global_allocator: false,
203 pub fn cstore(&self) -> &CStore {
207 pub fn into_cstore(self) -> CStore {
211 fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
213 self.cstore.iter_crate_data(|cnum, data| {
214 if data.name() != name {
219 Some(hash) if hash == data.hash() => {
227 // When the hash is None we're dealing with a top-level dependency
228 // in which case we may have a specification on the command line for
229 // this library. Even though an upstream library may have loaded
230 // something of the same name, we have to make sure it was loaded
231 // from the exact same location as well.
233 // We're also sure to compare *paths*, not actual byte slices. The
234 // `source` stores paths which are normalized which may be different
235 // from the strings on the command line.
236 let source = self.cstore.get_crate_data(cnum).cdata.source();
237 if let Some(entry) = self.sess.opts.externs.get(&name.as_str()) {
238 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
239 if let Some(mut files) = entry.files() {
241 let l = fs::canonicalize(l).ok();
242 source.dylib.as_ref().map(|p| &p.0) == l.as_ref()
243 || source.rlib.as_ref().map(|p| &p.0) == l.as_ref()
251 // Alright, so we've gotten this far which means that `data` has the
252 // right name, we don't have a hash, and we don't have a --extern
253 // pointing for ourselves. We're still not quite yet done because we
254 // have to make sure that this crate was found in the crate lookup
255 // path (this is a top-level dependency) as we don't want to
256 // implicitly load anything inside the dependency lookup path.
257 let prev_kind = source
260 .or(source.rlib.as_ref())
261 .or(source.rmeta.as_ref())
262 .expect("No sources for crate")
264 if kind.matches(prev_kind) {
271 fn verify_no_symbol_conflicts(&self, span: Span, root: &CrateRoot<'_>) {
272 // Check for (potential) conflicts with the local crate
273 if self.local_crate_name == root.name()
274 && self.sess.local_crate_disambiguator() == root.disambiguator()
280 "the current crate is indistinguishable from one of its \
281 dependencies: it has the same crate-name `{}` and was \
282 compiled with the same `-C metadata` arguments. This \
283 will result in symbol conflicts between the two.",
289 // Check for conflicts with any crate loaded so far
290 self.cstore.iter_crate_data(|_, other| {
291 if other.name() == root.name() && // same crate-name
292 other.disambiguator() == root.disambiguator() && // same crate-disambiguator
293 other.hash() != root.hash()
300 "found two different crates with name `{}` that are \
301 not distinguished by differing `-C metadata`. This \
302 will result in symbol conflicts between the two.",
312 host_lib: Option<Library>,
313 root: Option<&CratePaths>,
319 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
321 let Library { source, metadata } = lib;
322 let crate_root = metadata.get_root();
323 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
324 self.verify_no_symbol_conflicts(span, &crate_root);
327 self.sess.opts.externs.get(&name.as_str()).map(|e| e.is_private_dep).unwrap_or(false);
329 info!("register crate `{}` (private_dep = {})", crate_root.name(), private_dep);
331 // Claim this crate number and cache it
332 let cnum = self.cstore.alloc_new_crate_num();
334 // Maintain a reference to the top most crate.
335 // Stash paths for top-most crate locally if necessary.
337 let root = if let Some(root) = root {
340 crate_paths = CratePaths::new(crate_root.name(), source.clone());
344 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, span, dep_kind);
346 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
348 let (dlsym_source, dlsym_root) = match &host_lib {
349 Some(host_lib) => (&host_lib.source, {
350 temp_root = host_lib.metadata.get_root();
353 None => (&source, &crate_root),
355 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
356 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.disambiguator(), span))
361 self.cstore.set_crate_data(
380 fn load_proc_macro<'b>(
382 locator: &mut CrateLocator<'b>,
384 ) -> Option<(LoadResult, Option<Library>)>
388 // Use a new crate locator so trying to load a proc macro doesn't affect the error
390 let mut proc_macro_locator = locator.clone();
392 // Try to load a proc macro
393 proc_macro_locator.is_proc_macro = Some(true);
395 // Load the proc macro crate for the target
396 let (locator, target_result) = if self.sess.opts.debugging_opts.dual_proc_macros {
397 proc_macro_locator.reset();
398 let result = match self.load(&mut proc_macro_locator)? {
399 LoadResult::Previous(cnum) => return Some((LoadResult::Previous(cnum), None)),
400 LoadResult::Loaded(library) => Some(LoadResult::Loaded(library)),
402 locator.hash = locator.host_hash;
403 // Use the locator when looking for the host proc macro crate, as that is required
404 // so we want it to affect the error message
407 (&mut proc_macro_locator, None)
410 // Load the proc macro crate for the host
413 locator.is_proc_macro = Some(true);
414 locator.target = &self.sess.host;
415 locator.triple = TargetTriple::from_triple(config::host_triple());
416 locator.filesearch = self.sess.host_filesearch(path_kind);
418 let host_result = self.load(locator)?;
420 Some(if self.sess.opts.debugging_opts.dual_proc_macros {
421 let host_result = match host_result {
422 LoadResult::Previous(..) => {
423 panic!("host and target proc macros must be loaded in lock-step")
425 LoadResult::Loaded(library) => library,
427 (target_result.unwrap(), Some(host_result))
433 fn resolve_crate<'b>(
438 dep: Option<(&'b CratePaths, &'b CrateDep)>,
440 self.maybe_resolve_crate(name, span, dep_kind, dep).unwrap_or_else(|err| err.report())
443 fn maybe_resolve_crate<'b>(
447 mut dep_kind: DepKind,
448 dep: Option<(&'b CratePaths, &'b CrateDep)>,
449 ) -> Result<CrateNum, LoadError<'b>> {
450 info!("resolving crate `{}`", name);
451 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
452 Some((root, dep)) => (
456 Some(&dep.extra_filename[..]),
457 PathKind::Dependency,
459 None => (None, None, None, None, PathKind::Crate),
461 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
462 (LoadResult::Previous(cnum), None)
464 info!("falling back to a load");
465 let mut locator = CrateLocator::new(
467 self.metadata_loader,
476 Some(false), // is_proc_macro
479 self.load(&mut locator)
482 dep_kind = DepKind::MacrosOnly;
483 self.load_proc_macro(&mut locator, path_kind)
485 .ok_or_else(move || LoadError::LocatorError(locator))?
489 (LoadResult::Previous(cnum), None) => {
490 let data = self.cstore.get_crate_data(cnum);
491 if data.is_proc_macro_crate() {
492 dep_kind = DepKind::MacrosOnly;
494 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
497 (LoadResult::Loaded(library), host_library) => {
498 Ok(self.register_crate(host_library, root, span, library, dep_kind, name))
504 fn load(&self, locator: &mut CrateLocator<'_>) -> Option<LoadResult> {
505 let library = locator.maybe_load_library_crate()?;
507 // In the case that we're loading a crate, but not matching
508 // against a hash, we could load a crate which has the same hash
509 // as an already loaded crate. If this is the case prevent
510 // duplicates by just using the first crate.
512 // Note that we only do this for target triple crates, though, as we
513 // don't want to match a host crate against an equivalent target one
515 let root = library.metadata.get_root();
516 if locator.triple == self.sess.opts.target_triple {
517 let mut result = LoadResult::Loaded(library);
518 self.cstore.iter_crate_data(|cnum, data| {
519 if data.name() == root.name() && root.hash() == data.hash() {
520 assert!(locator.hash.is_none());
521 info!("load success, going to previous cnum: {}", cnum);
522 result = LoadResult::Previous(cnum);
527 Some(LoadResult::Loaded(library))
531 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
532 let cmeta = self.cstore.get_crate_data(cnum);
533 if cmeta.update_extern_crate(extern_crate) {
534 // Propagate the extern crate info to dependencies if it was updated.
535 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
536 for &dep_cnum in cmeta.dependencies().iter() {
537 self.update_extern_crate(dep_cnum, extern_crate);
542 // Go through the crate metadata and load any crates that it references
543 fn resolve_crate_deps(
546 crate_root: &CrateRoot<'_>,
547 metadata: &MetadataBlob,
552 debug!("resolving deps of external crate");
553 if crate_root.is_proc_macro_crate() {
554 return CrateNumMap::new();
557 // The map from crate numbers in the crate we're resolving to local crate numbers.
558 // We map 0 and all other holes in the map to our parent crate. The "additional"
559 // self-dependencies should be harmless.
560 std::iter::once(krate)
561 .chain(crate_root.decode_crate_deps(metadata).map(|dep| {
563 "resolving dep crate {} hash: `{}` extra filename: `{}`",
564 dep.name, dep.hash, dep.extra_filename
566 let dep_kind = match dep_kind {
567 DepKind::MacrosOnly => DepKind::MacrosOnly,
570 self.resolve_crate(dep.name, span, dep_kind, Some((root, &dep)))
575 fn dlsym_proc_macros(
578 disambiguator: CrateDisambiguator,
580 ) -> &'static [ProcMacro] {
581 use crate::dynamic_lib::DynamicLibrary;
584 // Make sure the path contains a / or the linker will search for it.
585 let path = env::current_dir().unwrap().join(path);
586 let lib = match DynamicLibrary::open(Some(&path)) {
588 Err(err) => self.sess.span_fatal(span, &err),
591 let sym = self.sess.generate_proc_macro_decls_symbol(disambiguator);
593 let sym = match lib.symbol(&sym) {
595 Err(err) => self.sess.span_fatal(span, &err),
597 *(sym as *const &[ProcMacro])
600 // Intentionally leak the dynamic library. We can't ever unload it
601 // since the library can make things that will live arbitrarily long.
602 std::mem::forget(lib);
607 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
608 // If we're only compiling an rlib, then there's no need to select a
609 // panic runtime, so we just skip this section entirely.
611 self.sess.crate_types.borrow().iter().any(|ct| *ct != config::CrateType::Rlib);
613 info!("panic runtime injection skipped, only generating rlib");
617 // If we need a panic runtime, we try to find an existing one here. At
618 // the same time we perform some general validation of the DAG we've got
619 // going such as ensuring everything has a compatible panic strategy.
621 // The logic for finding the panic runtime here is pretty much the same
622 // as the allocator case with the only addition that the panic strategy
623 // compilation mode also comes into play.
624 let desired_strategy = self.sess.panic_strategy();
625 let mut runtime_found = false;
626 let mut needs_panic_runtime = attr::contains_name(&krate.attrs, sym::needs_panic_runtime);
628 self.cstore.iter_crate_data(|cnum, data| {
629 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
630 if data.is_panic_runtime() {
631 // Inject a dependency from all #![needs_panic_runtime] to this
632 // #![panic_runtime] crate.
633 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
634 data.needs_panic_runtime()
636 runtime_found = runtime_found || data.dep_kind() == DepKind::Explicit;
640 // If an explicitly linked and matching panic runtime was found, or if
641 // we just don't need one at all, then we're done here and there's
642 // nothing else to do.
643 if !needs_panic_runtime || runtime_found {
647 // By this point we know that we (a) need a panic runtime and (b) no
648 // panic runtime was explicitly linked. Here we just load an appropriate
649 // default runtime for our panic strategy and then inject the
652 // We may resolve to an already loaded crate (as the crate may not have
653 // been explicitly linked prior to this) and we may re-inject
654 // dependencies again, but both of those situations are fine.
656 // Also note that we have yet to perform validation of the crate graph
657 // in terms of everyone has a compatible panic runtime format, that's
658 // performed later as part of the `dependency_format` module.
659 let name = match desired_strategy {
660 PanicStrategy::Unwind => Symbol::intern("panic_unwind"),
661 PanicStrategy::Abort => Symbol::intern("panic_abort"),
663 info!("panic runtime not found -- loading {}", name);
665 let cnum = self.resolve_crate(name, DUMMY_SP, DepKind::Implicit, None);
666 let data = self.cstore.get_crate_data(cnum);
668 // Sanity check the loaded crate to ensure it is indeed a panic runtime
669 // and the panic strategy is indeed what we thought it was.
670 if !data.is_panic_runtime() {
671 self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
673 if data.panic_strategy() != desired_strategy {
674 self.sess.err(&format!(
675 "the crate `{}` does not have the panic \
678 desired_strategy.desc()
682 self.cstore.injected_panic_runtime = Some(cnum);
683 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
686 fn inject_profiler_runtime(&mut self) {
687 if self.sess.opts.debugging_opts.profile || self.sess.opts.cg.profile_generate.enabled() {
688 info!("loading profiler");
690 let name = Symbol::intern("profiler_builtins");
691 let cnum = self.resolve_crate(name, DUMMY_SP, DepKind::Implicit, None);
692 let data = self.cstore.get_crate_data(cnum);
694 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
695 if !data.is_profiler_runtime() {
696 self.sess.err("the crate `profiler_builtins` is not a profiler runtime");
701 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
702 self.cstore.has_global_allocator = match &*global_allocator_spans(krate) {
703 [span1, span2, ..] => {
705 .struct_span_err(*span2, "cannot define multiple global allocators")
706 .span_label(*span2, "cannot define a new global allocator")
707 .span_label(*span1, "previous global allocator defined here")
711 spans => !spans.is_empty(),
714 // Check to see if we actually need an allocator. This desire comes
715 // about through the `#![needs_allocator]` attribute and is typically
716 // written down in liballoc.
717 let mut needs_allocator = attr::contains_name(&krate.attrs, sym::needs_allocator);
718 self.cstore.iter_crate_data(|_, data| {
719 needs_allocator = needs_allocator || data.needs_allocator();
721 if !needs_allocator {
725 // At this point we've determined that we need an allocator. Let's see
726 // if our compilation session actually needs an allocator based on what
728 let all_rlib = self.sess.crate_types.borrow().iter().all(|ct| match *ct {
729 config::CrateType::Rlib => true,
736 // Ok, we need an allocator. Not only that but we're actually going to
737 // create an artifact that needs one linked in. Let's go find the one
738 // that we're going to link in.
740 // First up we check for global allocators. Look at the crate graph here
741 // and see what's a global allocator, including if we ourselves are a
743 let mut global_allocator =
744 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
745 self.cstore.iter_crate_data(|_, data| {
746 if !data.has_global_allocator() {
749 match global_allocator {
750 Some(other_crate) => {
751 self.sess.err(&format!(
752 "the `#[global_allocator]` in {} \
753 conflicts with global \
759 None => global_allocator = Some(data.name()),
762 if global_allocator.is_some() {
763 self.cstore.allocator_kind = Some(AllocatorKind::Global);
767 // Ok we haven't found a global allocator but we still need an
768 // allocator. At this point our allocator request is typically fulfilled
769 // by the standard library, denoted by the `#![default_lib_allocator]`
771 let mut has_default = attr::contains_name(&krate.attrs, sym::default_lib_allocator);
772 self.cstore.iter_crate_data(|_, data| {
773 if data.has_default_lib_allocator() {
780 "no global memory allocator found but one is \
781 required; link to std or \
782 add `#[global_allocator]` to a static item \
783 that implements the GlobalAlloc trait.",
786 self.cstore.allocator_kind = Some(AllocatorKind::Default);
789 fn inject_dependency_if(
793 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
795 // don't perform this validation if the session has errors, as one of
796 // those errors may indicate a circular dependency which could cause
797 // this to stack overflow.
798 if self.sess.has_errors() {
802 // Before we inject any dependencies, make sure we don't inject a
803 // circular dependency by validating that this crate doesn't
804 // transitively depend on any crates satisfying `needs_dep`.
805 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
806 let data = self.cstore.get_crate_data(dep);
807 if needs_dep(&data) {
808 self.sess.err(&format!(
809 "the crate `{}` cannot depend \
810 on a crate that needs {}, but \
812 self.cstore.get_crate_data(krate).name(),
819 // All crates satisfying `needs_dep` do not explicitly depend on the
820 // crate provided for this compile, but in order for this compilation to
821 // be successfully linked we need to inject a dependency (to order the
822 // crates on the command line correctly).
823 self.cstore.iter_crate_data(|cnum, data| {
824 if !needs_dep(data) {
828 info!("injecting a dep from {} to {}", cnum, krate);
829 data.add_dependency(krate);
833 pub fn postprocess(&mut self, krate: &ast::Crate) {
834 self.inject_profiler_runtime();
835 self.inject_allocator_crate(krate);
836 self.inject_panic_runtime(krate);
838 if log_enabled!(log::Level::Info) {
839 dump_crates(&self.cstore);
843 pub fn process_extern_crate(
846 definitions: &Definitions,
849 ast::ItemKind::ExternCrate(orig_name) => {
851 "resolving extern crate stmt. ident: {} orig_name: {:?}",
852 item.ident, orig_name
854 let name = match orig_name {
856 crate::validate_crate_name(
863 None => item.ident.name,
865 let dep_kind = if attr::contains_name(&item.attrs, sym::no_link) {
871 let cnum = self.resolve_crate(name, item.span, dep_kind, None);
873 let def_id = definitions.opt_local_def_id(item.id).unwrap();
874 let path_len = definitions.def_path(def_id.index).data.len();
875 self.update_extern_crate(
878 src: ExternCrateSource::Extern(def_id),
881 dependency_of: LOCAL_CRATE,
890 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> CrateNum {
891 let cnum = self.resolve_crate(name, span, DepKind::Explicit, None);
893 self.update_extern_crate(
896 src: ExternCrateSource::Path,
898 // to have the least priority in `update_extern_crate`
899 path_len: usize::max_value(),
900 dependency_of: LOCAL_CRATE,
907 pub fn maybe_process_path_extern(&mut self, name: Symbol, span: Span) -> Option<CrateNum> {
908 self.maybe_resolve_crate(name, span, DepKind::Explicit, None).ok()