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 pub struct CrateLoader<'a> {
55 // Immutable configuration.
57 metadata_loader: &'a MetadataLoaderDyn,
58 local_crate_name: Symbol,
61 used_extern_options: FxHashSet<Symbol>,
64 pub enum LoadedMacro {
65 MacroDef(ast::Item, Edition),
66 ProcMacro(SyntaxExtension),
69 crate struct Library {
70 pub source: CrateSource,
71 pub metadata: MetadataBlob,
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 struct CrateDump<'a>(&'a CStore);
96 impl<'a> std::fmt::Debug for CrateDump<'a> {
97 fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
98 writeln!(fmt, "resolved crates:")?;
99 // `iter_crate_data` does not allow returning values. Thus we use a mutable variable here
100 // that aggregates the value (and any errors that could happen).
101 let mut res = Ok(());
102 self.0.iter_crate_data(|cnum, data| {
105 writeln!(fmt, " name: {}", data.name())?;
106 writeln!(fmt, " cnum: {}", cnum)?;
107 writeln!(fmt, " hash: {}", data.hash())?;
108 writeln!(fmt, " reqd: {:?}", data.dep_kind())?;
109 let CrateSource { dylib, rlib, rmeta } = data.source();
110 if let Some(dylib) = dylib {
111 writeln!(fmt, " dylib: {}", dylib.0.display())?;
113 if let Some(rlib) = rlib {
114 writeln!(fmt, " rlib: {}", rlib.0.display())?;
116 if let Some(rmeta) = rmeta {
117 writeln!(fmt, " rmeta: {}", rmeta.0.display())?;
127 crate fn from_tcx(tcx: TyCtxt<'_>) -> &CStore {
128 tcx.cstore_as_any().downcast_ref::<CStore>().expect("`tcx.cstore` is not a `CStore`")
131 fn alloc_new_crate_num(&mut self) -> CrateNum {
132 self.metas.push(None);
133 CrateNum::new(self.metas.len() - 1)
136 crate fn get_crate_data(&self, cnum: CrateNum) -> CrateMetadataRef<'_> {
137 let cdata = self.metas[cnum]
139 .unwrap_or_else(|| panic!("Failed to get crate data for {:?}", cnum));
140 CrateMetadataRef { cdata, cstore: self }
143 fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
144 assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
145 self.metas[cnum] = Some(Lrc::new(data));
148 crate fn iter_crate_data(&self, mut f: impl FnMut(CrateNum, &CrateMetadata)) {
149 for (cnum, data) in self.metas.iter_enumerated() {
150 if let Some(data) = data {
156 fn push_dependencies_in_postorder(&self, deps: &mut Vec<CrateNum>, cnum: CrateNum) {
157 if !deps.contains(&cnum) {
158 let data = self.get_crate_data(cnum);
159 for &dep in data.dependencies().iter() {
161 self.push_dependencies_in_postorder(deps, dep);
169 crate fn crate_dependencies_in_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
170 let mut deps = Vec::new();
171 if cnum == LOCAL_CRATE {
172 self.iter_crate_data(|cnum, _| self.push_dependencies_in_postorder(&mut deps, cnum));
174 self.push_dependencies_in_postorder(&mut deps, cnum);
179 fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
180 let mut deps = self.crate_dependencies_in_postorder(cnum);
185 crate fn injected_panic_runtime(&self) -> Option<CrateNum> {
186 self.injected_panic_runtime
189 crate fn allocator_kind(&self) -> Option<AllocatorKind> {
193 crate fn has_global_allocator(&self) -> bool {
194 self.has_global_allocator
197 pub fn report_unused_deps(&self, tcx: TyCtxt<'_>) {
198 // We put the check for the option before the lint_level_at_node call
199 // because the call mutates internal state and introducing it
200 // leads to some ui tests failing.
201 if !tcx.sess.opts.json_unused_externs {
205 .lint_level_at_node(lint::builtin::UNUSED_CRATE_DEPENDENCIES, rustc_hir::CRATE_HIR_ID)
207 if level != lint::Level::Allow {
209 self.unused_externs.iter().map(|ident| ident.to_ident_string()).collect::<Vec<_>>();
210 let unused_externs = unused_externs.iter().map(String::as_str).collect::<Vec<&str>>();
214 .emit_unused_externs(level.as_str(), &unused_externs);
219 impl<'a> CrateLoader<'a> {
222 metadata_loader: &'a MetadataLoaderDyn,
223 local_crate_name: &str,
225 let mut stable_crate_ids = FxHashMap::default();
226 stable_crate_ids.insert(sess.local_stable_crate_id(), LOCAL_CRATE);
231 local_crate_name: Symbol::intern(local_crate_name),
233 // We add an empty entry for LOCAL_CRATE (which maps to zero) in
234 // order to make array indices in `metas` match with the
235 // corresponding `CrateNum`. This first entry will always remain
237 metas: IndexVec::from_elem_n(None, 1),
238 injected_panic_runtime: None,
239 allocator_kind: None,
240 has_global_allocator: false,
242 unused_externs: Vec::new(),
244 used_extern_options: Default::default(),
248 pub fn cstore(&self) -> &CStore {
252 pub fn into_cstore(self) -> CStore {
256 fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
258 self.cstore.iter_crate_data(|cnum, data| {
259 if data.name() != name {
260 tracing::trace!("{} did not match {}", data.name(), name);
265 Some(hash) if hash == data.hash() => {
270 debug!("actual hash {} did not match expected {}", hash, data.hash());
276 // When the hash is None we're dealing with a top-level dependency
277 // in which case we may have a specification on the command line for
278 // this library. Even though an upstream library may have loaded
279 // something of the same name, we have to make sure it was loaded
280 // from the exact same location as well.
282 // We're also sure to compare *paths*, not actual byte slices. The
283 // `source` stores paths which are normalized which may be different
284 // from the strings on the command line.
285 let source = self.cstore.get_crate_data(cnum).cdata.source();
286 if let Some(entry) = self.sess.opts.externs.get(&name.as_str()) {
287 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
288 if let Some(mut files) = entry.files() {
290 let l = l.canonicalized();
291 source.dylib.as_ref().map(|(p, _)| p) == Some(l)
292 || source.rlib.as_ref().map(|(p, _)| p) == Some(l)
293 || source.rmeta.as_ref().map(|(p, _)| p) == Some(l)
301 // Alright, so we've gotten this far which means that `data` has the
302 // right name, we don't have a hash, and we don't have a --extern
303 // pointing for ourselves. We're still not quite yet done because we
304 // have to make sure that this crate was found in the crate lookup
305 // path (this is a top-level dependency) as we don't want to
306 // implicitly load anything inside the dependency lookup path.
307 let prev_kind = source
310 .or(source.rlib.as_ref())
311 .or(source.rmeta.as_ref())
312 .expect("No sources for crate")
314 if kind.matches(prev_kind) {
318 "failed to load existing crate {}; kind {:?} did not match prev_kind {:?}",
319 name, kind, prev_kind
326 fn verify_no_symbol_conflicts(&self, root: &CrateRoot<'_>) -> Result<(), CrateError> {
327 // Check for (potential) conflicts with the local crate
328 if self.sess.local_stable_crate_id() == root.stable_crate_id() {
329 return Err(CrateError::SymbolConflictsCurrent(root.name()));
332 // Check for conflicts with any crate loaded so far
333 let mut res = Ok(());
334 self.cstore.iter_crate_data(|_, other| {
335 if other.stable_crate_id() == root.stable_crate_id() && // same stable crate id
336 other.hash() != root.hash()
339 res = Err(CrateError::SymbolConflictsOthers(root.name()));
346 fn verify_no_stable_crate_id_hash_conflicts(
348 root: &CrateRoot<'_>,
350 ) -> Result<(), CrateError> {
351 if let Some(existing) = self.cstore.stable_crate_ids.insert(root.stable_crate_id(), cnum) {
352 let crate_name0 = root.name();
353 let crate_name1 = self.cstore.get_crate_data(existing).name();
354 return Err(CrateError::StableCrateIdCollision(crate_name0, crate_name1));
362 host_lib: Option<Library>,
363 root: Option<&CratePaths>,
365 dep_kind: CrateDepKind,
367 ) -> Result<CrateNum, CrateError> {
368 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
370 let Library { source, metadata } = lib;
371 let crate_root = metadata.get_root();
372 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
375 self.sess.opts.externs.get(&name.as_str()).map_or(false, |e| e.is_private_dep);
377 // Claim this crate number and cache it
378 let cnum = self.cstore.alloc_new_crate_num();
381 "register crate `{}` (cnum = {}. private_dep = {})",
387 // Maintain a reference to the top most crate.
388 // Stash paths for top-most crate locally if necessary.
390 let root = if let Some(root) = root {
393 crate_paths = CratePaths::new(crate_root.name(), source.clone());
397 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, dep_kind)?;
399 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
401 let (dlsym_source, dlsym_root) = match &host_lib {
402 Some(host_lib) => (&host_lib.source, {
403 temp_root = host_lib.metadata.get_root();
406 None => (&source, &crate_root),
408 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
409 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.stable_crate_id())?)
414 // Perform some verification *after* resolve_crate_deps() above is
415 // known to have been successful. It seems that - in error cases - the
416 // cstore can be in a temporarily invalid state between cnum allocation
417 // and dependency resolution and the verification code would produce
418 // ICEs in that case (see #83045).
419 self.verify_no_symbol_conflicts(&crate_root)?;
420 self.verify_no_stable_crate_id_hash_conflicts(&crate_root, cnum)?;
422 let crate_metadata = CrateMetadata::new(
435 self.cstore.set_crate_data(cnum, crate_metadata);
440 fn load_proc_macro<'b>(
442 locator: &mut CrateLocator<'b>,
444 ) -> Result<Option<(LoadResult, Option<Library>)>, CrateError>
448 // Use a new crate locator so trying to load a proc macro doesn't affect the error
450 let mut proc_macro_locator = locator.clone();
452 // Try to load a proc macro
453 proc_macro_locator.is_proc_macro = Some(true);
455 // Load the proc macro crate for the target
456 let (locator, target_result) = if self.sess.opts.debugging_opts.dual_proc_macros {
457 proc_macro_locator.reset();
458 let result = match self.load(&mut proc_macro_locator)? {
459 Some(LoadResult::Previous(cnum)) => {
460 return Ok(Some((LoadResult::Previous(cnum), None)));
462 Some(LoadResult::Loaded(library)) => Some(LoadResult::Loaded(library)),
463 None => return Ok(None),
465 locator.hash = locator.host_hash;
466 // Use the locator when looking for the host proc macro crate, as that is required
467 // so we want it to affect the error message
470 (&mut proc_macro_locator, None)
473 // Load the proc macro crate for the host
476 locator.is_proc_macro = Some(true);
477 locator.target = &self.sess.host;
478 locator.triple = TargetTriple::from_triple(config::host_triple());
479 locator.filesearch = self.sess.host_filesearch(path_kind);
481 let host_result = match self.load(locator)? {
482 Some(host_result) => host_result,
483 None => return Ok(None),
486 Ok(Some(if self.sess.opts.debugging_opts.dual_proc_macros {
487 let host_result = match host_result {
488 LoadResult::Previous(..) => {
489 panic!("host and target proc macros must be loaded in lock-step")
491 LoadResult::Loaded(library) => library,
493 (target_result.unwrap(), Some(host_result))
499 fn resolve_crate<'b>(
503 dep_kind: CrateDepKind,
504 dep: Option<(&'b CratePaths, &'b CrateDep)>,
507 self.used_extern_options.insert(name);
509 self.maybe_resolve_crate(name, dep_kind, dep).unwrap_or_else(|err| {
511 self.maybe_resolve_crate(sym::core, CrateDepKind::Explicit, None).is_err();
512 err.report(&self.sess, span, missing_core)
516 fn maybe_resolve_crate<'b>(
519 mut dep_kind: CrateDepKind,
520 dep: Option<(&'b CratePaths, &'b CrateDep)>,
521 ) -> Result<CrateNum, CrateError> {
522 info!("resolving crate `{}`", name);
523 if !name.as_str().is_ascii() {
524 return Err(CrateError::NonAsciiName(name));
526 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
527 Some((root, dep)) => (
531 Some(&dep.extra_filename[..]),
532 PathKind::Dependency,
534 None => (None, None, None, None, PathKind::Crate),
536 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
537 (LoadResult::Previous(cnum), None)
539 info!("falling back to a load");
540 let mut locator = CrateLocator::new(
542 self.metadata_loader,
550 Some(false), // is_proc_macro
553 match self.load(&mut locator)? {
554 Some(res) => (res, None),
556 dep_kind = CrateDepKind::MacrosOnly;
557 match self.load_proc_macro(&mut locator, path_kind)? {
559 None => return Err(locator.into_error()),
566 (LoadResult::Previous(cnum), None) => {
567 let data = self.cstore.get_crate_data(cnum);
568 if data.is_proc_macro_crate() {
569 dep_kind = CrateDepKind::MacrosOnly;
571 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
574 (LoadResult::Loaded(library), host_library) => {
575 self.register_crate(host_library, root, library, dep_kind, name)
581 fn load(&self, locator: &mut CrateLocator<'_>) -> Result<Option<LoadResult>, CrateError> {
582 let library = match locator.maybe_load_library_crate()? {
583 Some(library) => library,
584 None => return Ok(None),
587 // In the case that we're loading a crate, but not matching
588 // against a hash, we could load a crate which has the same hash
589 // as an already loaded crate. If this is the case prevent
590 // duplicates by just using the first crate.
592 // Note that we only do this for target triple crates, though, as we
593 // don't want to match a host crate against an equivalent target one
595 let root = library.metadata.get_root();
596 Ok(Some(if locator.triple == self.sess.opts.target_triple {
597 let mut result = LoadResult::Loaded(library);
598 self.cstore.iter_crate_data(|cnum, data| {
599 if data.name() == root.name() && root.hash() == data.hash() {
600 assert!(locator.hash.is_none());
601 info!("load success, going to previous cnum: {}", cnum);
602 result = LoadResult::Previous(cnum);
607 LoadResult::Loaded(library)
611 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
612 let cmeta = self.cstore.get_crate_data(cnum);
613 if cmeta.update_extern_crate(extern_crate) {
614 // Propagate the extern crate info to dependencies if it was updated.
615 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
616 for &dep_cnum in cmeta.dependencies().iter() {
617 self.update_extern_crate(dep_cnum, extern_crate);
622 // Go through the crate metadata and load any crates that it references
623 fn resolve_crate_deps(
626 crate_root: &CrateRoot<'_>,
627 metadata: &MetadataBlob,
629 dep_kind: CrateDepKind,
630 ) -> Result<CrateNumMap, CrateError> {
631 debug!("resolving deps of external crate");
632 if crate_root.is_proc_macro_crate() {
633 return Ok(CrateNumMap::new());
636 // The map from crate numbers in the crate we're resolving to local crate numbers.
637 // We map 0 and all other holes in the map to our parent crate. The "additional"
638 // self-dependencies should be harmless.
639 let deps = crate_root.decode_crate_deps(metadata);
640 let mut crate_num_map = CrateNumMap::with_capacity(1 + deps.len());
641 crate_num_map.push(krate);
644 "resolving dep crate {} hash: `{}` extra filename: `{}`",
645 dep.name, dep.hash, dep.extra_filename
647 let dep_kind = match dep_kind {
648 CrateDepKind::MacrosOnly => CrateDepKind::MacrosOnly,
651 let cnum = self.maybe_resolve_crate(dep.name, dep_kind, Some((root, &dep)))?;
652 crate_num_map.push(cnum);
655 debug!("resolve_crate_deps: cnum_map for {:?} is {:?}", krate, crate_num_map);
659 fn dlsym_proc_macros(
662 stable_crate_id: StableCrateId,
663 ) -> Result<&'static [ProcMacro], CrateError> {
664 // Make sure the path contains a / or the linker will search for it.
665 let path = env::current_dir().unwrap().join(path);
666 let lib = match DynamicLibrary::open(&path) {
668 Err(s) => return Err(CrateError::DlOpen(s)),
671 let sym = self.sess.generate_proc_macro_decls_symbol(stable_crate_id);
673 let sym = match lib.symbol(&sym) {
675 Err(s) => return Err(CrateError::DlSym(s)),
677 *(sym as *const &[ProcMacro])
680 // Intentionally leak the dynamic library. We can't ever unload it
681 // since the library can make things that will live arbitrarily long.
682 std::mem::forget(lib);
687 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
688 // If we're only compiling an rlib, then there's no need to select a
689 // panic runtime, so we just skip this section entirely.
690 let any_non_rlib = self.sess.crate_types().iter().any(|ct| *ct != CrateType::Rlib);
692 info!("panic runtime injection skipped, only generating rlib");
696 // If we need a panic runtime, we try to find an existing one here. At
697 // the same time we perform some general validation of the DAG we've got
698 // going such as ensuring everything has a compatible panic strategy.
700 // The logic for finding the panic runtime here is pretty much the same
701 // as the allocator case with the only addition that the panic strategy
702 // compilation mode also comes into play.
703 let desired_strategy = self.sess.panic_strategy();
704 let mut runtime_found = false;
705 let mut needs_panic_runtime =
706 self.sess.contains_name(&krate.attrs, sym::needs_panic_runtime);
708 self.cstore.iter_crate_data(|cnum, data| {
709 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
710 if data.is_panic_runtime() {
711 // Inject a dependency from all #![needs_panic_runtime] to this
712 // #![panic_runtime] crate.
713 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
714 data.needs_panic_runtime()
716 runtime_found = runtime_found || data.dep_kind() == CrateDepKind::Explicit;
720 // If an explicitly linked and matching panic runtime was found, or if
721 // we just don't need one at all, then we're done here and there's
722 // nothing else to do.
723 if !needs_panic_runtime || runtime_found {
727 // By this point we know that we (a) need a panic runtime and (b) no
728 // panic runtime was explicitly linked. Here we just load an appropriate
729 // default runtime for our panic strategy and then inject the
732 // We may resolve to an already loaded crate (as the crate may not have
733 // been explicitly linked prior to this) and we may re-inject
734 // dependencies again, but both of those situations are fine.
736 // Also note that we have yet to perform validation of the crate graph
737 // in terms of everyone has a compatible panic runtime format, that's
738 // performed later as part of the `dependency_format` module.
739 let name = match desired_strategy {
740 PanicStrategy::Unwind => sym::panic_unwind,
741 PanicStrategy::Abort => sym::panic_abort,
743 info!("panic runtime not found -- loading {}", name);
745 let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
746 let data = self.cstore.get_crate_data(cnum);
748 // Sanity check the loaded crate to ensure it is indeed a panic runtime
749 // and the panic strategy is indeed what we thought it was.
750 if !data.is_panic_runtime() {
751 self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
753 if data.panic_strategy() != desired_strategy {
754 self.sess.err(&format!(
755 "the crate `{}` does not have the panic \
758 desired_strategy.desc()
762 self.cstore.injected_panic_runtime = Some(cnum);
763 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
766 fn inject_profiler_runtime(&mut self, krate: &ast::Crate) {
767 if (self.sess.instrument_coverage()
768 || self.sess.opts.debugging_opts.profile
769 || self.sess.opts.cg.profile_generate.enabled())
770 && !self.sess.opts.debugging_opts.no_profiler_runtime
772 info!("loading profiler");
774 if self.sess.contains_name(&krate.attrs, sym::no_core) {
776 "`profiler_builtins` crate (required by compiler options) \
777 is not compatible with crate attribute `#![no_core]`",
781 let name = sym::profiler_builtins;
782 let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
783 let data = self.cstore.get_crate_data(cnum);
785 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
786 if !data.is_profiler_runtime() {
787 self.sess.err("the crate `profiler_builtins` is not a profiler runtime");
792 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
793 self.cstore.has_global_allocator = match &*global_allocator_spans(&self.sess, krate) {
794 [span1, span2, ..] => {
796 .struct_span_err(*span2, "cannot define multiple global allocators")
797 .span_label(*span2, "cannot define a new global allocator")
798 .span_label(*span1, "previous global allocator defined here")
802 spans => !spans.is_empty(),
805 // Check to see if we actually need an allocator. This desire comes
806 // about through the `#![needs_allocator]` attribute and is typically
807 // written down in liballoc.
808 let mut needs_allocator = self.sess.contains_name(&krate.attrs, sym::needs_allocator);
809 self.cstore.iter_crate_data(|_, data| {
810 needs_allocator = needs_allocator || data.needs_allocator();
812 if !needs_allocator {
816 // At this point we've determined that we need an allocator. Let's see
817 // if our compilation session actually needs an allocator based on what
819 let all_rlib = self.sess.crate_types().iter().all(|ct| matches!(*ct, CrateType::Rlib));
824 // Ok, we need an allocator. Not only that but we're actually going to
825 // create an artifact that needs one linked in. Let's go find the one
826 // that we're going to link in.
828 // First up we check for global allocators. Look at the crate graph here
829 // and see what's a global allocator, including if we ourselves are a
831 let mut global_allocator =
832 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
833 self.cstore.iter_crate_data(|_, data| {
834 if !data.has_global_allocator() {
837 match global_allocator {
838 Some(other_crate) => {
839 self.sess.err(&format!(
840 "the `#[global_allocator]` in {} \
841 conflicts with global \
847 None => global_allocator = Some(data.name()),
850 if global_allocator.is_some() {
851 self.cstore.allocator_kind = Some(AllocatorKind::Global);
855 // Ok we haven't found a global allocator but we still need an
856 // allocator. At this point our allocator request is typically fulfilled
857 // by the standard library, denoted by the `#![default_lib_allocator]`
859 let mut has_default = self.sess.contains_name(&krate.attrs, sym::default_lib_allocator);
860 self.cstore.iter_crate_data(|_, data| {
861 if data.has_default_lib_allocator() {
868 "no global memory allocator found but one is \
869 required; link to std or \
870 add `#[global_allocator]` to a static item \
871 that implements the GlobalAlloc trait.",
874 self.cstore.allocator_kind = Some(AllocatorKind::Default);
877 fn inject_dependency_if(
881 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
883 // don't perform this validation if the session has errors, as one of
884 // those errors may indicate a circular dependency which could cause
885 // this to stack overflow.
886 if self.sess.has_errors() {
890 // Before we inject any dependencies, make sure we don't inject a
891 // circular dependency by validating that this crate doesn't
892 // transitively depend on any crates satisfying `needs_dep`.
893 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
894 let data = self.cstore.get_crate_data(dep);
895 if needs_dep(&data) {
896 self.sess.err(&format!(
897 "the crate `{}` cannot depend \
898 on a crate that needs {}, but \
900 self.cstore.get_crate_data(krate).name(),
907 // All crates satisfying `needs_dep` do not explicitly depend on the
908 // crate provided for this compile, but in order for this compilation to
909 // be successfully linked we need to inject a dependency (to order the
910 // crates on the command line correctly).
911 self.cstore.iter_crate_data(|cnum, data| {
912 if !needs_dep(data) {
916 info!("injecting a dep from {} to {}", cnum, krate);
917 data.add_dependency(krate);
921 fn report_unused_deps(&mut self, krate: &ast::Crate) {
922 // Make a point span rather than covering the whole file
923 let span = krate.span.shrink_to_lo();
924 // Complain about anything left over
925 for (name, entry) in self.sess.opts.externs.iter() {
926 if let ExternLocation::FoundInLibrarySearchDirectories = entry.location {
927 // Don't worry about pathless `--extern foo` sysroot references
930 let name_interned = Symbol::intern(name);
931 if self.used_extern_options.contains(&name_interned) {
935 // Got a real unused --extern
936 if self.sess.opts.json_unused_externs {
937 self.cstore.unused_externs.push(name_interned);
941 let diag = match self.sess.opts.extern_dep_specs.get(name) {
942 Some(loc) => BuiltinLintDiagnostics::ExternDepSpec(name.clone(), loc.into()),
944 // If we don't have a specific location, provide a json encoding of the `--extern`
946 let meta: BTreeMap<String, String> =
947 std::iter::once(("name".to_string(), name.to_string())).collect();
948 BuiltinLintDiagnostics::ExternDepSpec(
950 ExternDepSpec::Json(meta.to_json()),
954 self.sess.parse_sess.buffer_lint_with_diagnostic(
955 lint::builtin::UNUSED_CRATE_DEPENDENCIES,
959 "external crate `{}` unused in `{}`: remove the dependency or add `use {} as _;`",
961 self.local_crate_name,
968 pub fn postprocess(&mut self, krate: &ast::Crate) {
969 self.inject_profiler_runtime(krate);
970 self.inject_allocator_crate(krate);
971 self.inject_panic_runtime(krate);
973 self.report_unused_deps(krate);
975 info!("{:?}", CrateDump(&self.cstore));
978 pub fn process_extern_crate(
981 definitions: &Definitions,
985 ast::ItemKind::ExternCrate(orig_name) => {
987 "resolving extern crate stmt. ident: {} orig_name: {:?}",
988 item.ident, orig_name
990 let name = match orig_name {
992 validate_crate_name(self.sess, &orig_name.as_str(), Some(item.span));
995 None => item.ident.name,
997 let dep_kind = if self.sess.contains_name(&item.attrs, sym::no_link) {
998 CrateDepKind::MacrosOnly
1000 CrateDepKind::Explicit
1003 let cnum = self.resolve_crate(name, item.span, dep_kind, None);
1005 let path_len = definitions.def_path(def_id).data.len();
1006 self.update_extern_crate(
1009 src: ExternCrateSource::Extern(def_id.to_def_id()),
1012 dependency_of: LOCAL_CRATE,
1021 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> CrateNum {
1022 let cnum = self.resolve_crate(name, span, CrateDepKind::Explicit, None);
1024 self.update_extern_crate(
1027 src: ExternCrateSource::Path,
1029 // to have the least priority in `update_extern_crate`
1030 path_len: usize::MAX,
1031 dependency_of: LOCAL_CRATE,
1038 pub fn maybe_process_path_extern(&mut self, name: Symbol) -> Option<CrateNum> {
1039 self.maybe_resolve_crate(name, CrateDepKind::Explicit, None).ok()
1043 fn global_allocator_spans(sess: &Session, krate: &ast::Crate) -> Vec<Span> {
1049 impl<'ast, 'a> visit::Visitor<'ast> for Finder<'a> {
1050 fn visit_item(&mut self, item: &'ast ast::Item) {
1051 if item.ident.name == self.name
1052 && self.sess.contains_name(&item.attrs, sym::rustc_std_internal_symbol)
1054 self.spans.push(item.span);
1056 visit::walk_item(self, item)
1060 let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::alloc));
1061 let mut f = Finder { sess, name, spans: Vec::new() };
1062 visit::walk_crate(&mut f, krate);