1 //! Validates all used crates and extern libraries and loads their metadata
3 use crate::dynamic_lib::DynamicLibrary;
4 use crate::locator::{CrateError, CrateLocator, CratePaths};
5 use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
7 use rustc_ast::expand::allocator::AllocatorKind;
8 use rustc_ast::{self as ast, *};
9 use rustc_data_structures::fx::FxHashSet;
10 use rustc_data_structures::svh::Svh;
11 use rustc_data_structures::sync::Lrc;
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::{CrateDepKind, CrateSource, ExternCrate};
17 use rustc_middle::middle::cstore::{ExternCrateSource, MetadataLoaderDyn};
18 use rustc_middle::ty::TyCtxt;
19 use rustc_serialize::json::ToJson;
20 use rustc_session::config::{self, CrateType, ExternLocation};
21 use rustc_session::lint::{self, BuiltinLintDiagnostics, ExternDepSpec};
22 use rustc_session::output::validate_crate_name;
23 use rustc_session::search_paths::PathKind;
24 use rustc_session::{CrateDisambiguator, Session};
25 use rustc_span::edition::Edition;
26 use rustc_span::symbol::{sym, Symbol};
27 use rustc_span::{Span, DUMMY_SP};
28 use rustc_target::spec::{PanicStrategy, TargetTriple};
30 use proc_macro::bridge::client::ProcMacro;
31 use std::collections::BTreeMap;
34 use tracing::{debug, info};
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,
72 /// A reference to `CrateMetadata` that can also give access to whole crate store when necessary.
73 #[derive(Clone, Copy)]
74 crate struct CrateMetadataRef<'a> {
75 pub cdata: &'a CrateMetadata,
76 pub cstore: &'a CStore,
79 impl std::ops::Deref for CrateMetadataRef<'_> {
80 type Target = CrateMetadata;
82 fn deref(&self) -> &Self::Target {
87 struct CrateDump<'a>(&'a CStore);
89 impl<'a> std::fmt::Debug for CrateDump<'a> {
90 fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
91 writeln!(fmt, "resolved crates:")?;
92 // `iter_crate_data` does not allow returning values. Thus we use a mutable variable here
93 // that aggregates the value (and any errors that could happen).
95 self.0.iter_crate_data(|cnum, data| {
98 writeln!(fmt, " name: {}", data.name())?;
99 writeln!(fmt, " cnum: {}", cnum)?;
100 writeln!(fmt, " hash: {}", data.hash())?;
101 writeln!(fmt, " reqd: {:?}", data.dep_kind())?;
102 let CrateSource { dylib, rlib, rmeta } = data.source();
103 if let Some(dylib) = dylib {
104 writeln!(fmt, " dylib: {}", dylib.0.display())?;
106 if let Some(rlib) = rlib {
107 writeln!(fmt, " rlib: {}", rlib.0.display())?;
109 if let Some(rmeta) = rmeta {
110 writeln!(fmt, " 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 {
227 tracing::trace!("{} did not match {}", data.name(), name);
232 Some(hash) if hash == data.hash() => {
237 debug!("actual hash {} did not match expected {}", hash, data.hash());
243 // When the hash is None we're dealing with a top-level dependency
244 // in which case we may have a specification on the command line for
245 // this library. Even though an upstream library may have loaded
246 // something of the same name, we have to make sure it was loaded
247 // from the exact same location as well.
249 // We're also sure to compare *paths*, not actual byte slices. The
250 // `source` stores paths which are normalized which may be different
251 // from the strings on the command line.
252 let source = self.cstore.get_crate_data(cnum).cdata.source();
253 if let Some(entry) = self.sess.opts.externs.get(&name.as_str()) {
254 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
255 if let Some(mut files) = entry.files() {
257 let l = l.canonicalized();
258 source.dylib.as_ref().map(|(p, _)| p) == Some(l)
259 || source.rlib.as_ref().map(|(p, _)| p) == Some(l)
260 || source.rmeta.as_ref().map(|(p, _)| p) == Some(l)
268 // Alright, so we've gotten this far which means that `data` has the
269 // right name, we don't have a hash, and we don't have a --extern
270 // pointing for ourselves. We're still not quite yet done because we
271 // have to make sure that this crate was found in the crate lookup
272 // path (this is a top-level dependency) as we don't want to
273 // implicitly load anything inside the dependency lookup path.
274 let prev_kind = source
277 .or(source.rlib.as_ref())
278 .or(source.rmeta.as_ref())
279 .expect("No sources for crate")
281 if kind.matches(prev_kind) {
285 "failed to load existing crate {}; kind {:?} did not match prev_kind {:?}",
286 name, kind, prev_kind
293 fn verify_no_symbol_conflicts(&self, root: &CrateRoot<'_>) -> Result<(), CrateError> {
294 // Check for (potential) conflicts with the local crate
295 if self.local_crate_name == root.name()
296 && self.sess.local_crate_disambiguator() == root.disambiguator()
298 return Err(CrateError::SymbolConflictsCurrent(root.name()));
301 // Check for conflicts with any crate loaded so far
302 let mut res = Ok(());
303 self.cstore.iter_crate_data(|_, other| {
304 if other.name() == root.name() && // same crate-name
305 other.disambiguator() == root.disambiguator() && // same crate-disambiguator
306 other.hash() != root.hash()
309 res = Err(CrateError::SymbolConflictsOthers(root.name()));
318 host_lib: Option<Library>,
319 root: Option<&CratePaths>,
321 dep_kind: CrateDepKind,
323 ) -> Result<CrateNum, CrateError> {
324 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
326 let Library { source, metadata } = lib;
327 let crate_root = metadata.get_root();
328 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
329 self.verify_no_symbol_conflicts(&crate_root)?;
332 self.sess.opts.externs.get(&name.as_str()).map_or(false, |e| e.is_private_dep);
334 // Claim this crate number and cache it
335 let cnum = self.cstore.alloc_new_crate_num();
338 "register crate `{}` (cnum = {}. private_dep = {})",
344 // Maintain a reference to the top most crate.
345 // Stash paths for top-most crate locally if necessary.
347 let root = if let Some(root) = root {
350 crate_paths = CratePaths::new(crate_root.name(), source.clone());
354 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, dep_kind)?;
356 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
358 let (dlsym_source, dlsym_root) = match &host_lib {
359 Some(host_lib) => (&host_lib.source, {
360 temp_root = host_lib.metadata.get_root();
363 None => (&source, &crate_root),
365 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
366 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.disambiguator())?)
371 let crate_metadata = CrateMetadata::new(
384 self.cstore.set_crate_data(cnum, crate_metadata);
389 fn load_proc_macro<'b>(
391 locator: &mut CrateLocator<'b>,
393 ) -> Result<Option<(LoadResult, Option<Library>)>, CrateError>
397 // Use a new crate locator so trying to load a proc macro doesn't affect the error
399 let mut proc_macro_locator = locator.clone();
401 // Try to load a proc macro
402 proc_macro_locator.is_proc_macro = Some(true);
404 // Load the proc macro crate for the target
405 let (locator, target_result) = if self.sess.opts.debugging_opts.dual_proc_macros {
406 proc_macro_locator.reset();
407 let result = match self.load(&mut proc_macro_locator)? {
408 Some(LoadResult::Previous(cnum)) => {
409 return Ok(Some((LoadResult::Previous(cnum), None)));
411 Some(LoadResult::Loaded(library)) => Some(LoadResult::Loaded(library)),
412 None => return Ok(None),
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 = match self.load(locator)? {
431 Some(host_result) => host_result,
432 None => return Ok(None),
435 Ok(Some(if self.sess.opts.debugging_opts.dual_proc_macros {
436 let host_result = match host_result {
437 LoadResult::Previous(..) => {
438 panic!("host and target proc macros must be loaded in lock-step")
440 LoadResult::Loaded(library) => library,
442 (target_result.unwrap(), Some(host_result))
448 fn resolve_crate<'b>(
452 dep_kind: CrateDepKind,
453 dep: Option<(&'b CratePaths, &'b CrateDep)>,
456 self.used_extern_options.insert(name);
458 self.maybe_resolve_crate(name, dep_kind, dep)
459 .unwrap_or_else(|err| err.report(self.sess, span))
462 fn maybe_resolve_crate<'b>(
465 mut dep_kind: CrateDepKind,
466 dep: Option<(&'b CratePaths, &'b CrateDep)>,
467 ) -> Result<CrateNum, CrateError> {
468 info!("resolving crate `{}`", name);
469 if !name.as_str().is_ascii() {
470 return Err(CrateError::NonAsciiName(name));
472 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
473 Some((root, dep)) => (
477 Some(&dep.extra_filename[..]),
478 PathKind::Dependency,
480 None => (None, None, None, None, PathKind::Crate),
482 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
483 (LoadResult::Previous(cnum), None)
485 info!("falling back to a load");
486 let mut locator = CrateLocator::new(
488 self.metadata_loader,
496 Some(false), // is_proc_macro
499 match self.load(&mut locator)? {
500 Some(res) => (res, None),
502 dep_kind = CrateDepKind::MacrosOnly;
503 match self.load_proc_macro(&mut locator, path_kind)? {
505 None => return Err(locator.into_error()),
512 (LoadResult::Previous(cnum), None) => {
513 let data = self.cstore.get_crate_data(cnum);
514 if data.is_proc_macro_crate() {
515 dep_kind = CrateDepKind::MacrosOnly;
517 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
520 (LoadResult::Loaded(library), host_library) => {
521 self.register_crate(host_library, root, library, dep_kind, name)
527 fn load(&self, locator: &mut CrateLocator<'_>) -> Result<Option<LoadResult>, CrateError> {
528 let library = match locator.maybe_load_library_crate()? {
529 Some(library) => library,
530 None => return Ok(None),
533 // In the case that we're loading a crate, but not matching
534 // against a hash, we could load a crate which has the same hash
535 // as an already loaded crate. If this is the case prevent
536 // duplicates by just using the first crate.
538 // Note that we only do this for target triple crates, though, as we
539 // don't want to match a host crate against an equivalent target one
541 let root = library.metadata.get_root();
542 Ok(Some(if locator.triple == self.sess.opts.target_triple {
543 let mut result = LoadResult::Loaded(library);
544 self.cstore.iter_crate_data(|cnum, data| {
545 if data.name() == root.name() && root.hash() == data.hash() {
546 assert!(locator.hash.is_none());
547 info!("load success, going to previous cnum: {}", cnum);
548 result = LoadResult::Previous(cnum);
553 LoadResult::Loaded(library)
557 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
558 let cmeta = self.cstore.get_crate_data(cnum);
559 if cmeta.update_extern_crate(extern_crate) {
560 // Propagate the extern crate info to dependencies if it was updated.
561 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
562 for &dep_cnum in cmeta.dependencies().iter() {
563 self.update_extern_crate(dep_cnum, extern_crate);
568 // Go through the crate metadata and load any crates that it references
569 fn resolve_crate_deps(
572 crate_root: &CrateRoot<'_>,
573 metadata: &MetadataBlob,
575 dep_kind: CrateDepKind,
576 ) -> Result<CrateNumMap, CrateError> {
577 debug!("resolving deps of external crate");
578 if crate_root.is_proc_macro_crate() {
579 return Ok(CrateNumMap::new());
582 // The map from crate numbers in the crate we're resolving to local crate numbers.
583 // We map 0 and all other holes in the map to our parent crate. The "additional"
584 // self-dependencies should be harmless.
585 let deps = crate_root.decode_crate_deps(metadata);
586 let mut crate_num_map = CrateNumMap::with_capacity(1 + deps.len());
587 crate_num_map.push(krate);
590 "resolving dep crate {} hash: `{}` extra filename: `{}`",
591 dep.name, dep.hash, dep.extra_filename
593 let dep_kind = match dep_kind {
594 CrateDepKind::MacrosOnly => CrateDepKind::MacrosOnly,
597 let cnum = self.maybe_resolve_crate(dep.name, dep_kind, Some((root, &dep)))?;
598 crate_num_map.push(cnum);
601 debug!("resolve_crate_deps: cnum_map for {:?} is {:?}", krate, crate_num_map);
605 fn dlsym_proc_macros(
608 disambiguator: CrateDisambiguator,
609 ) -> Result<&'static [ProcMacro], CrateError> {
610 // Make sure the path contains a / or the linker will search for it.
611 let path = env::current_dir().unwrap().join(path);
612 let lib = match DynamicLibrary::open(&path) {
614 Err(s) => return Err(CrateError::DlOpen(s)),
617 let sym = self.sess.generate_proc_macro_decls_symbol(disambiguator);
619 let sym = match lib.symbol(&sym) {
621 Err(s) => return Err(CrateError::DlSym(s)),
623 *(sym as *const &[ProcMacro])
626 // Intentionally leak the dynamic library. We can't ever unload it
627 // since the library can make things that will live arbitrarily long.
628 std::mem::forget(lib);
633 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
634 // If we're only compiling an rlib, then there's no need to select a
635 // panic runtime, so we just skip this section entirely.
636 let any_non_rlib = self.sess.crate_types().iter().any(|ct| *ct != CrateType::Rlib);
638 info!("panic runtime injection skipped, only generating rlib");
642 // If we need a panic runtime, we try to find an existing one here. At
643 // the same time we perform some general validation of the DAG we've got
644 // going such as ensuring everything has a compatible panic strategy.
646 // The logic for finding the panic runtime here is pretty much the same
647 // as the allocator case with the only addition that the panic strategy
648 // compilation mode also comes into play.
649 let desired_strategy = self.sess.panic_strategy();
650 let mut runtime_found = false;
651 let mut needs_panic_runtime =
652 self.sess.contains_name(&krate.attrs, sym::needs_panic_runtime);
654 self.cstore.iter_crate_data(|cnum, data| {
655 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
656 if data.is_panic_runtime() {
657 // Inject a dependency from all #![needs_panic_runtime] to this
658 // #![panic_runtime] crate.
659 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
660 data.needs_panic_runtime()
662 runtime_found = runtime_found || data.dep_kind() == CrateDepKind::Explicit;
666 // If an explicitly linked and matching panic runtime was found, or if
667 // we just don't need one at all, then we're done here and there's
668 // nothing else to do.
669 if !needs_panic_runtime || runtime_found {
673 // By this point we know that we (a) need a panic runtime and (b) no
674 // panic runtime was explicitly linked. Here we just load an appropriate
675 // default runtime for our panic strategy and then inject the
678 // We may resolve to an already loaded crate (as the crate may not have
679 // been explicitly linked prior to this) and we may re-inject
680 // dependencies again, but both of those situations are fine.
682 // Also note that we have yet to perform validation of the crate graph
683 // in terms of everyone has a compatible panic runtime format, that's
684 // performed later as part of the `dependency_format` module.
685 let name = match desired_strategy {
686 PanicStrategy::Unwind => sym::panic_unwind,
687 PanicStrategy::Abort => sym::panic_abort,
689 info!("panic runtime not found -- loading {}", name);
691 let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
692 let data = self.cstore.get_crate_data(cnum);
694 // Sanity check the loaded crate to ensure it is indeed a panic runtime
695 // and the panic strategy is indeed what we thought it was.
696 if !data.is_panic_runtime() {
697 self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
699 if data.panic_strategy() != desired_strategy {
700 self.sess.err(&format!(
701 "the crate `{}` does not have the panic \
704 desired_strategy.desc()
708 self.cstore.injected_panic_runtime = Some(cnum);
709 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
712 fn inject_profiler_runtime(&mut self, krate: &ast::Crate) {
713 if (self.sess.opts.debugging_opts.instrument_coverage
714 || self.sess.opts.debugging_opts.profile
715 || self.sess.opts.cg.profile_generate.enabled())
716 && !self.sess.opts.debugging_opts.no_profiler_runtime
718 info!("loading profiler");
720 if self.sess.contains_name(&krate.attrs, sym::no_core) {
722 "`profiler_builtins` crate (required by compiler options) \
723 is not compatible with crate attribute `#![no_core]`",
727 let name = sym::profiler_builtins;
728 let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
729 let data = self.cstore.get_crate_data(cnum);
731 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
732 if !data.is_profiler_runtime() {
733 self.sess.err("the crate `profiler_builtins` is not a profiler runtime");
738 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
739 self.cstore.has_global_allocator = match &*global_allocator_spans(&self.sess, krate) {
740 [span1, span2, ..] => {
742 .struct_span_err(*span2, "cannot define multiple global allocators")
743 .span_label(*span2, "cannot define a new global allocator")
744 .span_label(*span1, "previous global allocator defined here")
748 spans => !spans.is_empty(),
751 // Check to see if we actually need an allocator. This desire comes
752 // about through the `#![needs_allocator]` attribute and is typically
753 // written down in liballoc.
754 let mut needs_allocator = self.sess.contains_name(&krate.attrs, sym::needs_allocator);
755 self.cstore.iter_crate_data(|_, data| {
756 needs_allocator = needs_allocator || data.needs_allocator();
758 if !needs_allocator {
762 // At this point we've determined that we need an allocator. Let's see
763 // if our compilation session actually needs an allocator based on what
765 let all_rlib = self.sess.crate_types().iter().all(|ct| matches!(*ct, CrateType::Rlib));
770 // Ok, we need an allocator. Not only that but we're actually going to
771 // create an artifact that needs one linked in. Let's go find the one
772 // that we're going to link in.
774 // First up we check for global allocators. Look at the crate graph here
775 // and see what's a global allocator, including if we ourselves are a
777 let mut global_allocator =
778 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
779 self.cstore.iter_crate_data(|_, data| {
780 if !data.has_global_allocator() {
783 match global_allocator {
784 Some(other_crate) => {
785 self.sess.err(&format!(
786 "the `#[global_allocator]` in {} \
787 conflicts with global \
793 None => global_allocator = Some(data.name()),
796 if global_allocator.is_some() {
797 self.cstore.allocator_kind = Some(AllocatorKind::Global);
801 // Ok we haven't found a global allocator but we still need an
802 // allocator. At this point our allocator request is typically fulfilled
803 // by the standard library, denoted by the `#![default_lib_allocator]`
805 let mut has_default = self.sess.contains_name(&krate.attrs, sym::default_lib_allocator);
806 self.cstore.iter_crate_data(|_, data| {
807 if data.has_default_lib_allocator() {
814 "no global memory allocator found but one is \
815 required; link to std or \
816 add `#[global_allocator]` to a static item \
817 that implements the GlobalAlloc trait.",
820 self.cstore.allocator_kind = Some(AllocatorKind::Default);
823 fn inject_dependency_if(
827 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
829 // don't perform this validation if the session has errors, as one of
830 // those errors may indicate a circular dependency which could cause
831 // this to stack overflow.
832 if self.sess.has_errors() {
836 // Before we inject any dependencies, make sure we don't inject a
837 // circular dependency by validating that this crate doesn't
838 // transitively depend on any crates satisfying `needs_dep`.
839 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
840 let data = self.cstore.get_crate_data(dep);
841 if needs_dep(&data) {
842 self.sess.err(&format!(
843 "the crate `{}` cannot depend \
844 on a crate that needs {}, but \
846 self.cstore.get_crate_data(krate).name(),
853 // All crates satisfying `needs_dep` do not explicitly depend on the
854 // crate provided for this compile, but in order for this compilation to
855 // be successfully linked we need to inject a dependency (to order the
856 // crates on the command line correctly).
857 self.cstore.iter_crate_data(|cnum, data| {
858 if !needs_dep(data) {
862 info!("injecting a dep from {} to {}", cnum, krate);
863 data.add_dependency(krate);
867 fn report_unused_deps(&mut self, krate: &ast::Crate) {
868 // Make a point span rather than covering the whole file
869 let span = krate.span.shrink_to_lo();
870 // Complain about anything left over
871 for (name, entry) in self.sess.opts.externs.iter() {
872 if let ExternLocation::FoundInLibrarySearchDirectories = entry.location {
873 // Don't worry about pathless `--extern foo` sysroot references
876 if self.used_extern_options.contains(&Symbol::intern(name)) {
880 // Got a real unused --extern
881 let diag = match self.sess.opts.extern_dep_specs.get(name) {
882 Some(loc) => BuiltinLintDiagnostics::ExternDepSpec(name.clone(), loc.into()),
884 // If we don't have a specific location, provide a json encoding of the `--extern`
886 let meta: BTreeMap<String, String> =
887 std::iter::once(("name".to_string(), name.to_string())).collect();
888 BuiltinLintDiagnostics::ExternDepSpec(
890 ExternDepSpec::Json(meta.to_json()),
894 self.sess.parse_sess.buffer_lint_with_diagnostic(
895 lint::builtin::UNUSED_CRATE_DEPENDENCIES,
899 "external crate `{}` unused in `{}`: remove the dependency or add `use {} as _;`",
901 self.local_crate_name,
908 pub fn postprocess(&mut self, krate: &ast::Crate) {
909 self.inject_profiler_runtime(krate);
910 self.inject_allocator_crate(krate);
911 self.inject_panic_runtime(krate);
913 info!("{:?}", CrateDump(&self.cstore));
915 self.report_unused_deps(krate);
918 pub fn process_extern_crate(
921 definitions: &Definitions,
925 ast::ItemKind::ExternCrate(orig_name) => {
927 "resolving extern crate stmt. ident: {} orig_name: {:?}",
928 item.ident, orig_name
930 let name = match orig_name {
932 validate_crate_name(self.sess, &orig_name.as_str(), Some(item.span));
935 None => item.ident.name,
937 let dep_kind = if self.sess.contains_name(&item.attrs, sym::no_link) {
938 CrateDepKind::MacrosOnly
940 CrateDepKind::Explicit
943 let cnum = self.resolve_crate(name, item.span, dep_kind, None);
945 let path_len = definitions.def_path(def_id).data.len();
946 self.update_extern_crate(
949 src: ExternCrateSource::Extern(def_id.to_def_id()),
952 dependency_of: LOCAL_CRATE,
961 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> CrateNum {
962 let cnum = self.resolve_crate(name, span, CrateDepKind::Explicit, None);
964 self.update_extern_crate(
967 src: ExternCrateSource::Path,
969 // to have the least priority in `update_extern_crate`
970 path_len: usize::MAX,
971 dependency_of: LOCAL_CRATE,
978 pub fn maybe_process_path_extern(&mut self, name: Symbol) -> Option<CrateNum> {
979 self.maybe_resolve_crate(name, CrateDepKind::Explicit, None).ok()
983 fn global_allocator_spans(sess: &Session, krate: &ast::Crate) -> Vec<Span> {
989 impl<'ast, 'a> visit::Visitor<'ast> for Finder<'a> {
990 fn visit_item(&mut self, item: &'ast ast::Item) {
991 if item.ident.name == self.name
992 && self.sess.contains_name(&item.attrs, sym::rustc_std_internal_symbol)
994 self.spans.push(item.span);
996 visit::walk_item(self, item)
1000 let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::alloc));
1001 let mut f = Finder { sess, name, spans: Vec::new() };
1002 visit::walk_crate(&mut f, krate);