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::{FxHashMap, 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, StableCrateId, 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::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,
46 /// This map is used to verify we get no hash conflicts between
47 /// `StableCrateId` values.
48 stable_crate_ids: FxHashMap<StableCrateId, CrateNum>,
50 /// Unused externs of the crate
51 unused_externs: Vec<Symbol>,
54 impl std::fmt::Debug for CStore {
55 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
56 f.debug_struct("CStore").finish_non_exhaustive()
60 pub struct CrateLoader<'a> {
61 // Immutable configuration.
63 metadata_loader: Box<MetadataLoaderDyn>,
64 local_crate_name: Symbol,
67 used_extern_options: FxHashSet<Symbol>,
70 pub enum LoadedMacro {
71 MacroDef(ast::Item, Edition),
72 ProcMacro(SyntaxExtension),
75 crate struct Library {
76 pub source: CrateSource,
77 pub metadata: MetadataBlob,
85 /// A reference to `CrateMetadata` that can also give access to whole crate store when necessary.
86 #[derive(Clone, Copy)]
87 crate struct CrateMetadataRef<'a> {
88 pub cdata: &'a CrateMetadata,
89 pub cstore: &'a CStore,
92 impl std::ops::Deref for CrateMetadataRef<'_> {
93 type Target = CrateMetadata;
95 fn deref(&self) -> &Self::Target {
100 struct CrateDump<'a>(&'a CStore);
102 impl<'a> std::fmt::Debug for CrateDump<'a> {
103 fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
104 writeln!(fmt, "resolved crates:")?;
105 // `iter_crate_data` does not allow returning values. Thus we use a mutable variable here
106 // that aggregates the value (and any errors that could happen).
107 let mut res = Ok(());
108 self.0.iter_crate_data(|cnum, data| {
111 writeln!(fmt, " name: {}", data.name())?;
112 writeln!(fmt, " cnum: {}", cnum)?;
113 writeln!(fmt, " hash: {}", data.hash())?;
114 writeln!(fmt, " reqd: {:?}", data.dep_kind())?;
115 let CrateSource { dylib, rlib, rmeta } = data.source();
116 if let Some(dylib) = dylib {
117 writeln!(fmt, " dylib: {}", dylib.0.display())?;
119 if let Some(rlib) = rlib {
120 writeln!(fmt, " rlib: {}", rlib.0.display())?;
122 if let Some(rmeta) = rmeta {
123 writeln!(fmt, " rmeta: {}", rmeta.0.display())?;
133 pub fn from_tcx(tcx: TyCtxt<'_>) -> &CStore {
134 tcx.cstore_untracked()
136 .downcast_ref::<CStore>()
137 .expect("`tcx.cstore` is not a `CStore`")
140 fn alloc_new_crate_num(&mut self) -> CrateNum {
141 self.metas.push(None);
142 CrateNum::new(self.metas.len() - 1)
145 crate fn get_crate_data(&self, cnum: CrateNum) -> CrateMetadataRef<'_> {
146 let cdata = self.metas[cnum]
148 .unwrap_or_else(|| panic!("Failed to get crate data for {:?}", cnum));
149 CrateMetadataRef { cdata, cstore: self }
152 fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
153 assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
154 self.metas[cnum] = Some(Lrc::new(data));
157 crate fn iter_crate_data(&self, mut f: impl FnMut(CrateNum, &CrateMetadata)) {
158 for (cnum, data) in self.metas.iter_enumerated() {
159 if let Some(data) = data {
165 fn push_dependencies_in_postorder(&self, deps: &mut Vec<CrateNum>, cnum: CrateNum) {
166 if !deps.contains(&cnum) {
167 let data = self.get_crate_data(cnum);
168 for &dep in data.dependencies().iter() {
170 self.push_dependencies_in_postorder(deps, dep);
178 crate fn crate_dependencies_in_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
179 let mut deps = Vec::new();
180 if cnum == LOCAL_CRATE {
181 self.iter_crate_data(|cnum, _| self.push_dependencies_in_postorder(&mut deps, cnum));
183 self.push_dependencies_in_postorder(&mut deps, cnum);
188 fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
189 let mut deps = self.crate_dependencies_in_postorder(cnum);
194 crate fn injected_panic_runtime(&self) -> Option<CrateNum> {
195 self.injected_panic_runtime
198 crate fn allocator_kind(&self) -> Option<AllocatorKind> {
202 crate fn has_global_allocator(&self) -> bool {
203 self.has_global_allocator
206 pub fn report_unused_deps(&self, tcx: TyCtxt<'_>) {
207 // We put the check for the option before the lint_level_at_node call
208 // because the call mutates internal state and introducing it
209 // leads to some ui tests failing.
210 if !tcx.sess.opts.json_unused_externs {
214 .lint_level_at_node(lint::builtin::UNUSED_CRATE_DEPENDENCIES, rustc_hir::CRATE_HIR_ID)
216 if level != lint::Level::Allow {
218 self.unused_externs.iter().map(|ident| ident.to_ident_string()).collect::<Vec<_>>();
219 let unused_externs = unused_externs.iter().map(String::as_str).collect::<Vec<&str>>();
223 .emit_unused_externs(level.as_str(), &unused_externs);
228 impl<'a> CrateLoader<'a> {
231 metadata_loader: Box<MetadataLoaderDyn>,
232 local_crate_name: &str,
234 let mut stable_crate_ids = FxHashMap::default();
235 stable_crate_ids.insert(sess.local_stable_crate_id(), LOCAL_CRATE);
240 local_crate_name: Symbol::intern(local_crate_name),
242 // We add an empty entry for LOCAL_CRATE (which maps to zero) in
243 // order to make array indices in `metas` match with the
244 // corresponding `CrateNum`. This first entry will always remain
246 metas: IndexVec::from_elem_n(None, 1),
247 injected_panic_runtime: None,
248 allocator_kind: None,
249 has_global_allocator: false,
251 unused_externs: Vec::new(),
253 used_extern_options: Default::default(),
257 pub fn cstore(&self) -> &CStore {
261 pub fn into_cstore(self) -> CStore {
265 fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
267 self.cstore.iter_crate_data(|cnum, data| {
268 if data.name() != name {
269 tracing::trace!("{} did not match {}", data.name(), name);
274 Some(hash) if hash == data.hash() => {
279 debug!("actual hash {} did not match expected {}", hash, data.hash());
285 // When the hash is None we're dealing with a top-level dependency
286 // in which case we may have a specification on the command line for
287 // this library. Even though an upstream library may have loaded
288 // something of the same name, we have to make sure it was loaded
289 // from the exact same location as well.
291 // We're also sure to compare *paths*, not actual byte slices. The
292 // `source` stores paths which are normalized which may be different
293 // from the strings on the command line.
294 let source = self.cstore.get_crate_data(cnum).cdata.source();
295 if let Some(entry) = self.sess.opts.externs.get(&name.as_str()) {
296 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
297 if let Some(mut files) = entry.files() {
299 let l = l.canonicalized();
300 source.dylib.as_ref().map(|(p, _)| p) == Some(l)
301 || source.rlib.as_ref().map(|(p, _)| p) == Some(l)
302 || source.rmeta.as_ref().map(|(p, _)| p) == Some(l)
310 // Alright, so we've gotten this far which means that `data` has the
311 // right name, we don't have a hash, and we don't have a --extern
312 // pointing for ourselves. We're still not quite yet done because we
313 // have to make sure that this crate was found in the crate lookup
314 // path (this is a top-level dependency) as we don't want to
315 // implicitly load anything inside the dependency lookup path.
316 let prev_kind = source
319 .or(source.rlib.as_ref())
320 .or(source.rmeta.as_ref())
321 .expect("No sources for crate")
323 if kind.matches(prev_kind) {
327 "failed to load existing crate {}; kind {:?} did not match prev_kind {:?}",
328 name, kind, prev_kind
335 fn verify_no_symbol_conflicts(&self, root: &CrateRoot<'_>) -> Result<(), CrateError> {
336 // Check for (potential) conflicts with the local crate
337 if self.sess.local_stable_crate_id() == root.stable_crate_id() {
338 return Err(CrateError::SymbolConflictsCurrent(root.name()));
341 // Check for conflicts with any crate loaded so far
342 let mut res = Ok(());
343 self.cstore.iter_crate_data(|_, other| {
344 if other.stable_crate_id() == root.stable_crate_id() && // same stable crate id
345 other.hash() != root.hash()
348 res = Err(CrateError::SymbolConflictsOthers(root.name()));
355 fn verify_no_stable_crate_id_hash_conflicts(
357 root: &CrateRoot<'_>,
359 ) -> Result<(), CrateError> {
360 if let Some(existing) = self.cstore.stable_crate_ids.insert(root.stable_crate_id(), cnum) {
361 let crate_name0 = root.name();
362 let crate_name1 = self.cstore.get_crate_data(existing).name();
363 return Err(CrateError::StableCrateIdCollision(crate_name0, crate_name1));
371 host_lib: Option<Library>,
372 root: Option<&CratePaths>,
374 dep_kind: CrateDepKind,
376 ) -> Result<CrateNum, CrateError> {
377 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
379 let Library { source, metadata } = lib;
380 let crate_root = metadata.get_root();
381 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
384 self.sess.opts.externs.get(&name.as_str()).map_or(false, |e| e.is_private_dep);
386 // Claim this crate number and cache it
387 let cnum = self.cstore.alloc_new_crate_num();
390 "register crate `{}` (cnum = {}. private_dep = {})",
396 // Maintain a reference to the top most crate.
397 // Stash paths for top-most crate locally if necessary.
399 let root = if let Some(root) = root {
402 crate_paths = CratePaths::new(crate_root.name(), source.clone());
406 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, dep_kind)?;
408 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
410 let (dlsym_source, dlsym_root) = match &host_lib {
411 Some(host_lib) => (&host_lib.source, {
412 temp_root = host_lib.metadata.get_root();
415 None => (&source, &crate_root),
417 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
418 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.stable_crate_id())?)
423 // Perform some verification *after* resolve_crate_deps() above is
424 // known to have been successful. It seems that - in error cases - the
425 // cstore can be in a temporarily invalid state between cnum allocation
426 // and dependency resolution and the verification code would produce
427 // ICEs in that case (see #83045).
428 self.verify_no_symbol_conflicts(&crate_root)?;
429 self.verify_no_stable_crate_id_hash_conflicts(&crate_root, cnum)?;
431 let crate_metadata = CrateMetadata::new(
444 self.cstore.set_crate_data(cnum, crate_metadata);
449 fn load_proc_macro<'b>(
451 locator: &mut CrateLocator<'b>,
453 ) -> Result<Option<(LoadResult, Option<Library>)>, CrateError>
457 // Use a new crate locator so trying to load a proc macro doesn't affect the error
459 let mut proc_macro_locator = locator.clone();
461 // Try to load a proc macro
462 proc_macro_locator.is_proc_macro = Some(true);
464 // Load the proc macro crate for the target
465 let (locator, target_result) = if self.sess.opts.debugging_opts.dual_proc_macros {
466 proc_macro_locator.reset();
467 let result = match self.load(&mut proc_macro_locator)? {
468 Some(LoadResult::Previous(cnum)) => {
469 return Ok(Some((LoadResult::Previous(cnum), None)));
471 Some(LoadResult::Loaded(library)) => Some(LoadResult::Loaded(library)),
472 None => return Ok(None),
474 locator.hash = locator.host_hash;
475 // Use the locator when looking for the host proc macro crate, as that is required
476 // so we want it to affect the error message
479 (&mut proc_macro_locator, None)
482 // Load the proc macro crate for the host
485 locator.is_proc_macro = Some(true);
486 locator.target = &self.sess.host;
487 locator.triple = TargetTriple::from_triple(config::host_triple());
488 locator.filesearch = self.sess.host_filesearch(path_kind);
490 let host_result = match self.load(locator)? {
491 Some(host_result) => host_result,
492 None => return Ok(None),
495 Ok(Some(if self.sess.opts.debugging_opts.dual_proc_macros {
496 let host_result = match host_result {
497 LoadResult::Previous(..) => {
498 panic!("host and target proc macros must be loaded in lock-step")
500 LoadResult::Loaded(library) => library,
502 (target_result.unwrap(), Some(host_result))
508 fn resolve_crate<'b>(
512 dep_kind: CrateDepKind,
513 dep: Option<(&'b CratePaths, &'b CrateDep)>,
516 self.used_extern_options.insert(name);
518 self.maybe_resolve_crate(name, dep_kind, dep).unwrap_or_else(|err| {
520 self.maybe_resolve_crate(sym::core, CrateDepKind::Explicit, None).is_err();
521 err.report(&self.sess, span, missing_core)
525 fn maybe_resolve_crate<'b>(
528 mut dep_kind: CrateDepKind,
529 dep: Option<(&'b CratePaths, &'b CrateDep)>,
530 ) -> Result<CrateNum, CrateError> {
531 info!("resolving crate `{}`", name);
532 if !name.as_str().is_ascii() {
533 return Err(CrateError::NonAsciiName(name));
535 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
536 Some((root, dep)) => (
540 Some(&dep.extra_filename[..]),
541 PathKind::Dependency,
543 None => (None, None, None, None, PathKind::Crate),
545 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
546 (LoadResult::Previous(cnum), None)
548 info!("falling back to a load");
549 let mut locator = CrateLocator::new(
551 &*self.metadata_loader,
559 Some(false), // is_proc_macro
562 match self.load(&mut locator)? {
563 Some(res) => (res, None),
565 dep_kind = CrateDepKind::MacrosOnly;
566 match self.load_proc_macro(&mut locator, path_kind)? {
568 None => return Err(locator.into_error()),
575 (LoadResult::Previous(cnum), None) => {
576 let data = self.cstore.get_crate_data(cnum);
577 if data.is_proc_macro_crate() {
578 dep_kind = CrateDepKind::MacrosOnly;
580 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
583 (LoadResult::Loaded(library), host_library) => {
584 self.register_crate(host_library, root, library, dep_kind, name)
590 fn load(&self, locator: &mut CrateLocator<'_>) -> Result<Option<LoadResult>, CrateError> {
591 let library = match locator.maybe_load_library_crate()? {
592 Some(library) => library,
593 None => return Ok(None),
596 // In the case that we're loading a crate, but not matching
597 // against a hash, we could load a crate which has the same hash
598 // as an already loaded crate. If this is the case prevent
599 // duplicates by just using the first crate.
601 // Note that we only do this for target triple crates, though, as we
602 // don't want to match a host crate against an equivalent target one
604 let root = library.metadata.get_root();
605 // FIXME: why is this condition necessary? It was adding in #33625 but I
606 // don't know why and the original author doesn't remember ...
607 let can_reuse_cratenum =
608 locator.triple == self.sess.opts.target_triple || locator.is_proc_macro == Some(true);
609 Ok(Some(if can_reuse_cratenum {
610 let mut result = LoadResult::Loaded(library);
611 self.cstore.iter_crate_data(|cnum, data| {
612 if data.name() == root.name() && root.hash() == data.hash() {
613 assert!(locator.hash.is_none());
614 info!("load success, going to previous cnum: {}", cnum);
615 result = LoadResult::Previous(cnum);
620 LoadResult::Loaded(library)
624 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
625 let cmeta = self.cstore.get_crate_data(cnum);
626 if cmeta.update_extern_crate(extern_crate) {
627 // Propagate the extern crate info to dependencies if it was updated.
628 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
629 for &dep_cnum in cmeta.dependencies().iter() {
630 self.update_extern_crate(dep_cnum, extern_crate);
635 // Go through the crate metadata and load any crates that it references
636 fn resolve_crate_deps(
639 crate_root: &CrateRoot<'_>,
640 metadata: &MetadataBlob,
642 dep_kind: CrateDepKind,
643 ) -> Result<CrateNumMap, CrateError> {
644 debug!("resolving deps of external crate");
645 if crate_root.is_proc_macro_crate() {
646 return Ok(CrateNumMap::new());
649 // The map from crate numbers in the crate we're resolving to local crate numbers.
650 // We map 0 and all other holes in the map to our parent crate. The "additional"
651 // self-dependencies should be harmless.
652 let deps = crate_root.decode_crate_deps(metadata);
653 let mut crate_num_map = CrateNumMap::with_capacity(1 + deps.len());
654 crate_num_map.push(krate);
657 "resolving dep crate {} hash: `{}` extra filename: `{}`",
658 dep.name, dep.hash, dep.extra_filename
660 let dep_kind = match dep_kind {
661 CrateDepKind::MacrosOnly => CrateDepKind::MacrosOnly,
664 let cnum = self.maybe_resolve_crate(dep.name, dep_kind, Some((root, &dep)))?;
665 crate_num_map.push(cnum);
668 debug!("resolve_crate_deps: cnum_map for {:?} is {:?}", krate, crate_num_map);
672 fn dlsym_proc_macros(
675 stable_crate_id: StableCrateId,
676 ) -> Result<&'static [ProcMacro], CrateError> {
677 // Make sure the path contains a / or the linker will search for it.
678 let path = env::current_dir().unwrap().join(path);
679 let lib = match DynamicLibrary::open(&path) {
681 Err(s) => return Err(CrateError::DlOpen(s)),
684 let sym = self.sess.generate_proc_macro_decls_symbol(stable_crate_id);
686 let sym = match lib.symbol(&sym) {
688 Err(s) => return Err(CrateError::DlSym(s)),
690 *(sym as *const &[ProcMacro])
693 // Intentionally leak the dynamic library. We can't ever unload it
694 // since the library can make things that will live arbitrarily long.
695 std::mem::forget(lib);
700 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
701 // If we're only compiling an rlib, then there's no need to select a
702 // panic runtime, so we just skip this section entirely.
703 let any_non_rlib = self.sess.crate_types().iter().any(|ct| *ct != CrateType::Rlib);
705 info!("panic runtime injection skipped, only generating rlib");
709 // If we need a panic runtime, we try to find an existing one here. At
710 // the same time we perform some general validation of the DAG we've got
711 // going such as ensuring everything has a compatible panic strategy.
713 // The logic for finding the panic runtime here is pretty much the same
714 // as the allocator case with the only addition that the panic strategy
715 // compilation mode also comes into play.
716 let desired_strategy = self.sess.panic_strategy();
717 let mut runtime_found = false;
718 let mut needs_panic_runtime =
719 self.sess.contains_name(&krate.attrs, sym::needs_panic_runtime);
721 self.cstore.iter_crate_data(|cnum, data| {
722 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
723 if data.is_panic_runtime() {
724 // Inject a dependency from all #![needs_panic_runtime] to this
725 // #![panic_runtime] crate.
726 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
727 data.needs_panic_runtime()
729 runtime_found = runtime_found || data.dep_kind() == CrateDepKind::Explicit;
733 // If an explicitly linked and matching panic runtime was found, or if
734 // we just don't need one at all, then we're done here and there's
735 // nothing else to do.
736 if !needs_panic_runtime || runtime_found {
740 // By this point we know that we (a) need a panic runtime and (b) no
741 // panic runtime was explicitly linked. Here we just load an appropriate
742 // default runtime for our panic strategy and then inject the
745 // We may resolve to an already loaded crate (as the crate may not have
746 // been explicitly linked prior to this) and we may re-inject
747 // dependencies again, but both of those situations are fine.
749 // Also note that we have yet to perform validation of the crate graph
750 // in terms of everyone has a compatible panic runtime format, that's
751 // performed later as part of the `dependency_format` module.
752 let name = match desired_strategy {
753 PanicStrategy::Unwind => sym::panic_unwind,
754 PanicStrategy::Abort => sym::panic_abort,
756 info!("panic runtime not found -- loading {}", name);
758 let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
759 let data = self.cstore.get_crate_data(cnum);
761 // Sanity check the loaded crate to ensure it is indeed a panic runtime
762 // and the panic strategy is indeed what we thought it was.
763 if !data.is_panic_runtime() {
764 self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
766 if data.panic_strategy() != desired_strategy {
767 self.sess.err(&format!(
768 "the crate `{}` does not have the panic \
771 desired_strategy.desc()
775 self.cstore.injected_panic_runtime = Some(cnum);
776 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
779 fn inject_profiler_runtime(&mut self, krate: &ast::Crate) {
780 if self.sess.opts.debugging_opts.no_profiler_runtime
781 || !(self.sess.instrument_coverage()
782 || self.sess.opts.debugging_opts.profile
783 || self.sess.opts.cg.profile_generate.enabled())
788 info!("loading profiler");
790 let name = Symbol::intern(&self.sess.opts.debugging_opts.profiler_runtime);
791 if name == sym::profiler_builtins && self.sess.contains_name(&krate.attrs, sym::no_core) {
793 "`profiler_builtins` crate (required by compiler options) \
794 is not compatible with crate attribute `#![no_core]`",
798 let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
799 let data = self.cstore.get_crate_data(cnum);
801 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
802 if !data.is_profiler_runtime() {
803 self.sess.err(&format!("the crate `{}` is not a profiler runtime", name));
807 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
808 self.cstore.has_global_allocator = match &*global_allocator_spans(&self.sess, krate) {
809 [span1, span2, ..] => {
811 .struct_span_err(*span2, "cannot define multiple global allocators")
812 .span_label(*span2, "cannot define a new global allocator")
813 .span_label(*span1, "previous global allocator defined here")
817 spans => !spans.is_empty(),
820 // Check to see if we actually need an allocator. This desire comes
821 // about through the `#![needs_allocator]` attribute and is typically
822 // written down in liballoc.
823 let mut needs_allocator = self.sess.contains_name(&krate.attrs, sym::needs_allocator);
824 self.cstore.iter_crate_data(|_, data| {
825 needs_allocator = needs_allocator || data.needs_allocator();
827 if !needs_allocator {
831 // At this point we've determined that we need an allocator. Let's see
832 // if our compilation session actually needs an allocator based on what
834 let all_rlib = self.sess.crate_types().iter().all(|ct| matches!(*ct, CrateType::Rlib));
839 // Ok, we need an allocator. Not only that but we're actually going to
840 // create an artifact that needs one linked in. Let's go find the one
841 // that we're going to link in.
843 // First up we check for global allocators. Look at the crate graph here
844 // and see what's a global allocator, including if we ourselves are a
846 let mut global_allocator =
847 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
848 self.cstore.iter_crate_data(|_, data| {
849 if !data.has_global_allocator() {
852 match global_allocator {
853 Some(other_crate) => {
854 self.sess.err(&format!(
855 "the `#[global_allocator]` in {} \
856 conflicts with global \
862 None => global_allocator = Some(data.name()),
865 if global_allocator.is_some() {
866 self.cstore.allocator_kind = Some(AllocatorKind::Global);
870 // Ok we haven't found a global allocator but we still need an
871 // allocator. At this point our allocator request is typically fulfilled
872 // by the standard library, denoted by the `#![default_lib_allocator]`
874 let mut has_default = self.sess.contains_name(&krate.attrs, sym::default_lib_allocator);
875 self.cstore.iter_crate_data(|_, data| {
876 if data.has_default_lib_allocator() {
883 "no global memory allocator found but one is \
884 required; link to std or \
885 add `#[global_allocator]` to a static item \
886 that implements the GlobalAlloc trait.",
889 self.cstore.allocator_kind = Some(AllocatorKind::Default);
892 fn inject_dependency_if(
896 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
898 // don't perform this validation if the session has errors, as one of
899 // those errors may indicate a circular dependency which could cause
900 // this to stack overflow.
901 if self.sess.has_errors() {
905 // Before we inject any dependencies, make sure we don't inject a
906 // circular dependency by validating that this crate doesn't
907 // transitively depend on any crates satisfying `needs_dep`.
908 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
909 let data = self.cstore.get_crate_data(dep);
910 if needs_dep(&data) {
911 self.sess.err(&format!(
912 "the crate `{}` cannot depend \
913 on a crate that needs {}, but \
915 self.cstore.get_crate_data(krate).name(),
922 // All crates satisfying `needs_dep` do not explicitly depend on the
923 // crate provided for this compile, but in order for this compilation to
924 // be successfully linked we need to inject a dependency (to order the
925 // crates on the command line correctly).
926 self.cstore.iter_crate_data(|cnum, data| {
927 if !needs_dep(data) {
931 info!("injecting a dep from {} to {}", cnum, krate);
932 data.add_dependency(krate);
936 fn report_unused_deps(&mut self, krate: &ast::Crate) {
937 // Make a point span rather than covering the whole file
938 let span = krate.span.shrink_to_lo();
939 // Complain about anything left over
940 for (name, entry) in self.sess.opts.externs.iter() {
941 if let ExternLocation::FoundInLibrarySearchDirectories = entry.location {
942 // Don't worry about pathless `--extern foo` sysroot references
945 let name_interned = Symbol::intern(name);
946 if self.used_extern_options.contains(&name_interned) {
950 // Got a real unused --extern
951 if self.sess.opts.json_unused_externs {
952 self.cstore.unused_externs.push(name_interned);
956 let diag = match self.sess.opts.extern_dep_specs.get(name) {
957 Some(loc) => BuiltinLintDiagnostics::ExternDepSpec(name.clone(), loc.into()),
959 // If we don't have a specific location, provide a json encoding of the `--extern`
961 let meta: BTreeMap<String, String> =
962 std::iter::once(("name".to_string(), name.to_string())).collect();
963 BuiltinLintDiagnostics::ExternDepSpec(
965 ExternDepSpec::Json(meta.to_json()),
969 self.sess.parse_sess.buffer_lint_with_diagnostic(
970 lint::builtin::UNUSED_CRATE_DEPENDENCIES,
974 "external crate `{}` unused in `{}`: remove the dependency or add `use {} as _;`",
976 self.local_crate_name,
983 pub fn postprocess(&mut self, krate: &ast::Crate) {
984 self.inject_profiler_runtime(krate);
985 self.inject_allocator_crate(krate);
986 self.inject_panic_runtime(krate);
988 self.report_unused_deps(krate);
990 info!("{:?}", CrateDump(&self.cstore));
993 pub fn process_extern_crate(
996 definitions: &Definitions,
1000 ast::ItemKind::ExternCrate(orig_name) => {
1002 "resolving extern crate stmt. ident: {} orig_name: {:?}",
1003 item.ident, orig_name
1005 let name = match orig_name {
1006 Some(orig_name) => {
1007 validate_crate_name(self.sess, &orig_name.as_str(), Some(item.span));
1010 None => item.ident.name,
1012 let dep_kind = if self.sess.contains_name(&item.attrs, sym::no_link) {
1013 CrateDepKind::MacrosOnly
1015 CrateDepKind::Explicit
1018 let cnum = self.resolve_crate(name, item.span, dep_kind, None);
1020 let path_len = definitions.def_path(def_id).data.len();
1021 self.update_extern_crate(
1024 src: ExternCrateSource::Extern(def_id.to_def_id()),
1027 dependency_of: LOCAL_CRATE,
1036 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> CrateNum {
1037 let cnum = self.resolve_crate(name, span, CrateDepKind::Explicit, None);
1039 self.update_extern_crate(
1042 src: ExternCrateSource::Path,
1044 // to have the least priority in `update_extern_crate`
1045 path_len: usize::MAX,
1046 dependency_of: LOCAL_CRATE,
1053 pub fn maybe_process_path_extern(&mut self, name: Symbol) -> Option<CrateNum> {
1054 self.maybe_resolve_crate(name, CrateDepKind::Explicit, None).ok()
1058 fn global_allocator_spans(sess: &Session, krate: &ast::Crate) -> Vec<Span> {
1064 impl<'ast, 'a> visit::Visitor<'ast> for Finder<'a> {
1065 fn visit_item(&mut self, item: &'ast ast::Item) {
1066 if item.ident.name == self.name
1067 && self.sess.contains_name(&item.attrs, sym::rustc_std_internal_symbol)
1069 self.spans.push(item.span);
1071 visit::walk_item(self, item)
1075 let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::alloc));
1076 let mut f = Finder { sess, name, spans: Vec::new() };
1077 visit::walk_crate(&mut f, krate);