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: &'a 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 crate fn from_tcx(tcx: TyCtxt<'_>) -> &CStore {
134 tcx.cstore_as_any().downcast_ref::<CStore>().expect("`tcx.cstore` is not a `CStore`")
137 fn alloc_new_crate_num(&mut self) -> CrateNum {
138 self.metas.push(None);
139 CrateNum::new(self.metas.len() - 1)
142 crate fn get_crate_data(&self, cnum: CrateNum) -> CrateMetadataRef<'_> {
143 let cdata = self.metas[cnum]
145 .unwrap_or_else(|| panic!("Failed to get crate data for {:?}", cnum));
146 CrateMetadataRef { cdata, cstore: self }
149 fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
150 assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
151 self.metas[cnum] = Some(Lrc::new(data));
154 crate fn iter_crate_data(&self, mut f: impl FnMut(CrateNum, &CrateMetadata)) {
155 for (cnum, data) in self.metas.iter_enumerated() {
156 if let Some(data) = data {
162 fn push_dependencies_in_postorder(&self, deps: &mut Vec<CrateNum>, cnum: CrateNum) {
163 if !deps.contains(&cnum) {
164 let data = self.get_crate_data(cnum);
165 for &dep in data.dependencies().iter() {
167 self.push_dependencies_in_postorder(deps, dep);
175 crate fn crate_dependencies_in_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
176 let mut deps = Vec::new();
177 if cnum == LOCAL_CRATE {
178 self.iter_crate_data(|cnum, _| self.push_dependencies_in_postorder(&mut deps, cnum));
180 self.push_dependencies_in_postorder(&mut deps, cnum);
185 fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
186 let mut deps = self.crate_dependencies_in_postorder(cnum);
191 crate fn injected_panic_runtime(&self) -> Option<CrateNum> {
192 self.injected_panic_runtime
195 crate fn allocator_kind(&self) -> Option<AllocatorKind> {
199 crate fn has_global_allocator(&self) -> bool {
200 self.has_global_allocator
203 pub fn report_unused_deps(&self, tcx: TyCtxt<'_>) {
204 // We put the check for the option before the lint_level_at_node call
205 // because the call mutates internal state and introducing it
206 // leads to some ui tests failing.
207 if !tcx.sess.opts.json_unused_externs {
211 .lint_level_at_node(lint::builtin::UNUSED_CRATE_DEPENDENCIES, rustc_hir::CRATE_HIR_ID)
213 if level != lint::Level::Allow {
215 self.unused_externs.iter().map(|ident| ident.to_ident_string()).collect::<Vec<_>>();
216 let unused_externs = unused_externs.iter().map(String::as_str).collect::<Vec<&str>>();
220 .emit_unused_externs(level.as_str(), &unused_externs);
225 impl<'a> CrateLoader<'a> {
228 metadata_loader: &'a MetadataLoaderDyn,
229 local_crate_name: &str,
231 let mut stable_crate_ids = FxHashMap::default();
232 stable_crate_ids.insert(sess.local_stable_crate_id(), LOCAL_CRATE);
237 local_crate_name: Symbol::intern(local_crate_name),
239 // We add an empty entry for LOCAL_CRATE (which maps to zero) in
240 // order to make array indices in `metas` match with the
241 // corresponding `CrateNum`. This first entry will always remain
243 metas: IndexVec::from_elem_n(None, 1),
244 injected_panic_runtime: None,
245 allocator_kind: None,
246 has_global_allocator: false,
248 unused_externs: Vec::new(),
250 used_extern_options: Default::default(),
254 pub fn cstore(&self) -> &CStore {
258 pub fn into_cstore(self) -> CStore {
262 fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
264 self.cstore.iter_crate_data(|cnum, data| {
265 if data.name() != name {
266 tracing::trace!("{} did not match {}", data.name(), name);
271 Some(hash) if hash == data.hash() => {
276 debug!("actual hash {} did not match expected {}", hash, data.hash());
282 // When the hash is None we're dealing with a top-level dependency
283 // in which case we may have a specification on the command line for
284 // this library. Even though an upstream library may have loaded
285 // something of the same name, we have to make sure it was loaded
286 // from the exact same location as well.
288 // We're also sure to compare *paths*, not actual byte slices. The
289 // `source` stores paths which are normalized which may be different
290 // from the strings on the command line.
291 let source = self.cstore.get_crate_data(cnum).cdata.source();
292 if let Some(entry) = self.sess.opts.externs.get(&name.as_str()) {
293 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
294 if let Some(mut files) = entry.files() {
296 let l = l.canonicalized();
297 source.dylib.as_ref().map(|(p, _)| p) == Some(l)
298 || source.rlib.as_ref().map(|(p, _)| p) == Some(l)
299 || source.rmeta.as_ref().map(|(p, _)| p) == Some(l)
307 // Alright, so we've gotten this far which means that `data` has the
308 // right name, we don't have a hash, and we don't have a --extern
309 // pointing for ourselves. We're still not quite yet done because we
310 // have to make sure that this crate was found in the crate lookup
311 // path (this is a top-level dependency) as we don't want to
312 // implicitly load anything inside the dependency lookup path.
313 let prev_kind = source
316 .or(source.rlib.as_ref())
317 .or(source.rmeta.as_ref())
318 .expect("No sources for crate")
320 if kind.matches(prev_kind) {
324 "failed to load existing crate {}; kind {:?} did not match prev_kind {:?}",
325 name, kind, prev_kind
332 fn verify_no_symbol_conflicts(&self, root: &CrateRoot<'_>) -> Result<(), CrateError> {
333 // Check for (potential) conflicts with the local crate
334 if self.sess.local_stable_crate_id() == root.stable_crate_id() {
335 return Err(CrateError::SymbolConflictsCurrent(root.name()));
338 // Check for conflicts with any crate loaded so far
339 let mut res = Ok(());
340 self.cstore.iter_crate_data(|_, other| {
341 if other.stable_crate_id() == root.stable_crate_id() && // same stable crate id
342 other.hash() != root.hash()
345 res = Err(CrateError::SymbolConflictsOthers(root.name()));
352 fn verify_no_stable_crate_id_hash_conflicts(
354 root: &CrateRoot<'_>,
356 ) -> Result<(), CrateError> {
357 if let Some(existing) = self.cstore.stable_crate_ids.insert(root.stable_crate_id(), cnum) {
358 let crate_name0 = root.name();
359 let crate_name1 = self.cstore.get_crate_data(existing).name();
360 return Err(CrateError::StableCrateIdCollision(crate_name0, crate_name1));
368 host_lib: Option<Library>,
369 root: Option<&CratePaths>,
371 dep_kind: CrateDepKind,
373 ) -> Result<CrateNum, CrateError> {
374 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
376 let Library { source, metadata } = lib;
377 let crate_root = metadata.get_root();
378 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
381 self.sess.opts.externs.get(&name.as_str()).map_or(false, |e| e.is_private_dep);
383 // Claim this crate number and cache it
384 let cnum = self.cstore.alloc_new_crate_num();
387 "register crate `{}` (cnum = {}. private_dep = {})",
393 // Maintain a reference to the top most crate.
394 // Stash paths for top-most crate locally if necessary.
396 let root = if let Some(root) = root {
399 crate_paths = CratePaths::new(crate_root.name(), source.clone());
403 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, dep_kind)?;
405 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
407 let (dlsym_source, dlsym_root) = match &host_lib {
408 Some(host_lib) => (&host_lib.source, {
409 temp_root = host_lib.metadata.get_root();
412 None => (&source, &crate_root),
414 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
415 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.stable_crate_id())?)
420 // Perform some verification *after* resolve_crate_deps() above is
421 // known to have been successful. It seems that - in error cases - the
422 // cstore can be in a temporarily invalid state between cnum allocation
423 // and dependency resolution and the verification code would produce
424 // ICEs in that case (see #83045).
425 self.verify_no_symbol_conflicts(&crate_root)?;
426 self.verify_no_stable_crate_id_hash_conflicts(&crate_root, cnum)?;
428 let crate_metadata = CrateMetadata::new(
441 self.cstore.set_crate_data(cnum, crate_metadata);
446 fn load_proc_macro<'b>(
448 locator: &mut CrateLocator<'b>,
450 ) -> Result<Option<(LoadResult, Option<Library>)>, CrateError>
454 // Use a new crate locator so trying to load a proc macro doesn't affect the error
456 let mut proc_macro_locator = locator.clone();
458 // Try to load a proc macro
459 proc_macro_locator.is_proc_macro = Some(true);
461 // Load the proc macro crate for the target
462 let (locator, target_result) = if self.sess.opts.debugging_opts.dual_proc_macros {
463 proc_macro_locator.reset();
464 let result = match self.load(&mut proc_macro_locator)? {
465 Some(LoadResult::Previous(cnum)) => {
466 return Ok(Some((LoadResult::Previous(cnum), None)));
468 Some(LoadResult::Loaded(library)) => Some(LoadResult::Loaded(library)),
469 None => return Ok(None),
471 locator.hash = locator.host_hash;
472 // Use the locator when looking for the host proc macro crate, as that is required
473 // so we want it to affect the error message
476 (&mut proc_macro_locator, None)
479 // Load the proc macro crate for the host
482 locator.is_proc_macro = Some(true);
483 locator.target = &self.sess.host;
484 locator.triple = TargetTriple::from_triple(config::host_triple());
485 locator.filesearch = self.sess.host_filesearch(path_kind);
487 let host_result = match self.load(locator)? {
488 Some(host_result) => host_result,
489 None => return Ok(None),
492 Ok(Some(if self.sess.opts.debugging_opts.dual_proc_macros {
493 let host_result = match host_result {
494 LoadResult::Previous(..) => {
495 panic!("host and target proc macros must be loaded in lock-step")
497 LoadResult::Loaded(library) => library,
499 (target_result.unwrap(), Some(host_result))
505 fn resolve_crate<'b>(
509 dep_kind: CrateDepKind,
510 dep: Option<(&'b CratePaths, &'b CrateDep)>,
513 self.used_extern_options.insert(name);
515 self.maybe_resolve_crate(name, dep_kind, dep).unwrap_or_else(|err| {
517 self.maybe_resolve_crate(sym::core, CrateDepKind::Explicit, None).is_err();
518 err.report(&self.sess, span, missing_core)
522 fn maybe_resolve_crate<'b>(
525 mut dep_kind: CrateDepKind,
526 dep: Option<(&'b CratePaths, &'b CrateDep)>,
527 ) -> Result<CrateNum, CrateError> {
528 info!("resolving crate `{}`", name);
529 if !name.as_str().is_ascii() {
530 return Err(CrateError::NonAsciiName(name));
532 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
533 Some((root, dep)) => (
537 Some(&dep.extra_filename[..]),
538 PathKind::Dependency,
540 None => (None, None, None, None, PathKind::Crate),
542 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
543 (LoadResult::Previous(cnum), None)
545 info!("falling back to a load");
546 let mut locator = CrateLocator::new(
548 self.metadata_loader,
556 Some(false), // is_proc_macro
559 match self.load(&mut locator)? {
560 Some(res) => (res, None),
562 dep_kind = CrateDepKind::MacrosOnly;
563 match self.load_proc_macro(&mut locator, path_kind)? {
565 None => return Err(locator.into_error()),
572 (LoadResult::Previous(cnum), None) => {
573 let data = self.cstore.get_crate_data(cnum);
574 if data.is_proc_macro_crate() {
575 dep_kind = CrateDepKind::MacrosOnly;
577 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
580 (LoadResult::Loaded(library), host_library) => {
581 self.register_crate(host_library, root, library, dep_kind, name)
587 fn load(&self, locator: &mut CrateLocator<'_>) -> Result<Option<LoadResult>, CrateError> {
588 let library = match locator.maybe_load_library_crate()? {
589 Some(library) => library,
590 None => return Ok(None),
593 // In the case that we're loading a crate, but not matching
594 // against a hash, we could load a crate which has the same hash
595 // as an already loaded crate. If this is the case prevent
596 // duplicates by just using the first crate.
598 // Note that we only do this for target triple crates, though, as we
599 // don't want to match a host crate against an equivalent target one
601 let root = library.metadata.get_root();
602 Ok(Some(if locator.triple == self.sess.opts.target_triple {
603 let mut result = LoadResult::Loaded(library);
604 self.cstore.iter_crate_data(|cnum, data| {
605 if data.name() == root.name() && root.hash() == data.hash() {
606 assert!(locator.hash.is_none());
607 info!("load success, going to previous cnum: {}", cnum);
608 result = LoadResult::Previous(cnum);
613 LoadResult::Loaded(library)
617 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
618 let cmeta = self.cstore.get_crate_data(cnum);
619 if cmeta.update_extern_crate(extern_crate) {
620 // Propagate the extern crate info to dependencies if it was updated.
621 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
622 for &dep_cnum in cmeta.dependencies().iter() {
623 self.update_extern_crate(dep_cnum, extern_crate);
628 // Go through the crate metadata and load any crates that it references
629 fn resolve_crate_deps(
632 crate_root: &CrateRoot<'_>,
633 metadata: &MetadataBlob,
635 dep_kind: CrateDepKind,
636 ) -> Result<CrateNumMap, CrateError> {
637 debug!("resolving deps of external crate");
638 if crate_root.is_proc_macro_crate() {
639 return Ok(CrateNumMap::new());
642 // The map from crate numbers in the crate we're resolving to local crate numbers.
643 // We map 0 and all other holes in the map to our parent crate. The "additional"
644 // self-dependencies should be harmless.
645 let deps = crate_root.decode_crate_deps(metadata);
646 let mut crate_num_map = CrateNumMap::with_capacity(1 + deps.len());
647 crate_num_map.push(krate);
650 "resolving dep crate {} hash: `{}` extra filename: `{}`",
651 dep.name, dep.hash, dep.extra_filename
653 let dep_kind = match dep_kind {
654 CrateDepKind::MacrosOnly => CrateDepKind::MacrosOnly,
657 let cnum = self.maybe_resolve_crate(dep.name, dep_kind, Some((root, &dep)))?;
658 crate_num_map.push(cnum);
661 debug!("resolve_crate_deps: cnum_map for {:?} is {:?}", krate, crate_num_map);
665 fn dlsym_proc_macros(
668 stable_crate_id: StableCrateId,
669 ) -> Result<&'static [ProcMacro], CrateError> {
670 // Make sure the path contains a / or the linker will search for it.
671 let path = env::current_dir().unwrap().join(path);
672 let lib = match DynamicLibrary::open(&path) {
674 Err(s) => return Err(CrateError::DlOpen(s)),
677 let sym = self.sess.generate_proc_macro_decls_symbol(stable_crate_id);
679 let sym = match lib.symbol(&sym) {
681 Err(s) => return Err(CrateError::DlSym(s)),
683 *(sym as *const &[ProcMacro])
686 // Intentionally leak the dynamic library. We can't ever unload it
687 // since the library can make things that will live arbitrarily long.
688 std::mem::forget(lib);
693 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
694 // If we're only compiling an rlib, then there's no need to select a
695 // panic runtime, so we just skip this section entirely.
696 let any_non_rlib = self.sess.crate_types().iter().any(|ct| *ct != CrateType::Rlib);
698 info!("panic runtime injection skipped, only generating rlib");
702 // If we need a panic runtime, we try to find an existing one here. At
703 // the same time we perform some general validation of the DAG we've got
704 // going such as ensuring everything has a compatible panic strategy.
706 // The logic for finding the panic runtime here is pretty much the same
707 // as the allocator case with the only addition that the panic strategy
708 // compilation mode also comes into play.
709 let desired_strategy = self.sess.panic_strategy();
710 let mut runtime_found = false;
711 let mut needs_panic_runtime =
712 self.sess.contains_name(&krate.attrs, sym::needs_panic_runtime);
714 self.cstore.iter_crate_data(|cnum, data| {
715 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
716 if data.is_panic_runtime() {
717 // Inject a dependency from all #![needs_panic_runtime] to this
718 // #![panic_runtime] crate.
719 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
720 data.needs_panic_runtime()
722 runtime_found = runtime_found || data.dep_kind() == CrateDepKind::Explicit;
726 // If an explicitly linked and matching panic runtime was found, or if
727 // we just don't need one at all, then we're done here and there's
728 // nothing else to do.
729 if !needs_panic_runtime || runtime_found {
733 // By this point we know that we (a) need a panic runtime and (b) no
734 // panic runtime was explicitly linked. Here we just load an appropriate
735 // default runtime for our panic strategy and then inject the
738 // We may resolve to an already loaded crate (as the crate may not have
739 // been explicitly linked prior to this) and we may re-inject
740 // dependencies again, but both of those situations are fine.
742 // Also note that we have yet to perform validation of the crate graph
743 // in terms of everyone has a compatible panic runtime format, that's
744 // performed later as part of the `dependency_format` module.
745 let name = match desired_strategy {
746 PanicStrategy::Unwind => sym::panic_unwind,
747 PanicStrategy::Abort => sym::panic_abort,
749 info!("panic runtime not found -- loading {}", name);
751 let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
752 let data = self.cstore.get_crate_data(cnum);
754 // Sanity check the loaded crate to ensure it is indeed a panic runtime
755 // and the panic strategy is indeed what we thought it was.
756 if !data.is_panic_runtime() {
757 self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
759 if data.panic_strategy() != desired_strategy {
760 self.sess.err(&format!(
761 "the crate `{}` does not have the panic \
764 desired_strategy.desc()
768 self.cstore.injected_panic_runtime = Some(cnum);
769 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
772 fn inject_profiler_runtime(&mut self, krate: &ast::Crate) {
773 if (self.sess.instrument_coverage()
774 || self.sess.opts.debugging_opts.profile
775 || self.sess.opts.cg.profile_generate.enabled())
776 && !self.sess.opts.debugging_opts.no_profiler_runtime
778 info!("loading profiler");
780 if self.sess.contains_name(&krate.attrs, sym::no_core) {
782 "`profiler_builtins` crate (required by compiler options) \
783 is not compatible with crate attribute `#![no_core]`",
787 let name = sym::profiler_builtins;
788 let cnum = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit, None);
789 let data = self.cstore.get_crate_data(cnum);
791 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
792 if !data.is_profiler_runtime() {
793 self.sess.err("the crate `profiler_builtins` is not a profiler runtime");
798 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
799 self.cstore.has_global_allocator = match &*global_allocator_spans(&self.sess, krate) {
800 [span1, span2, ..] => {
802 .struct_span_err(*span2, "cannot define multiple global allocators")
803 .span_label(*span2, "cannot define a new global allocator")
804 .span_label(*span1, "previous global allocator defined here")
808 spans => !spans.is_empty(),
811 // Check to see if we actually need an allocator. This desire comes
812 // about through the `#![needs_allocator]` attribute and is typically
813 // written down in liballoc.
814 let mut needs_allocator = self.sess.contains_name(&krate.attrs, sym::needs_allocator);
815 self.cstore.iter_crate_data(|_, data| {
816 needs_allocator = needs_allocator || data.needs_allocator();
818 if !needs_allocator {
822 // At this point we've determined that we need an allocator. Let's see
823 // if our compilation session actually needs an allocator based on what
825 let all_rlib = self.sess.crate_types().iter().all(|ct| matches!(*ct, CrateType::Rlib));
830 // Ok, we need an allocator. Not only that but we're actually going to
831 // create an artifact that needs one linked in. Let's go find the one
832 // that we're going to link in.
834 // First up we check for global allocators. Look at the crate graph here
835 // and see what's a global allocator, including if we ourselves are a
837 let mut global_allocator =
838 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
839 self.cstore.iter_crate_data(|_, data| {
840 if !data.has_global_allocator() {
843 match global_allocator {
844 Some(other_crate) => {
845 self.sess.err(&format!(
846 "the `#[global_allocator]` in {} \
847 conflicts with global \
853 None => global_allocator = Some(data.name()),
856 if global_allocator.is_some() {
857 self.cstore.allocator_kind = Some(AllocatorKind::Global);
861 // Ok we haven't found a global allocator but we still need an
862 // allocator. At this point our allocator request is typically fulfilled
863 // by the standard library, denoted by the `#![default_lib_allocator]`
865 let mut has_default = self.sess.contains_name(&krate.attrs, sym::default_lib_allocator);
866 self.cstore.iter_crate_data(|_, data| {
867 if data.has_default_lib_allocator() {
874 "no global memory allocator found but one is \
875 required; link to std or \
876 add `#[global_allocator]` to a static item \
877 that implements the GlobalAlloc trait.",
880 self.cstore.allocator_kind = Some(AllocatorKind::Default);
883 fn inject_dependency_if(
887 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
889 // don't perform this validation if the session has errors, as one of
890 // those errors may indicate a circular dependency which could cause
891 // this to stack overflow.
892 if self.sess.has_errors() {
896 // Before we inject any dependencies, make sure we don't inject a
897 // circular dependency by validating that this crate doesn't
898 // transitively depend on any crates satisfying `needs_dep`.
899 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
900 let data = self.cstore.get_crate_data(dep);
901 if needs_dep(&data) {
902 self.sess.err(&format!(
903 "the crate `{}` cannot depend \
904 on a crate that needs {}, but \
906 self.cstore.get_crate_data(krate).name(),
913 // All crates satisfying `needs_dep` do not explicitly depend on the
914 // crate provided for this compile, but in order for this compilation to
915 // be successfully linked we need to inject a dependency (to order the
916 // crates on the command line correctly).
917 self.cstore.iter_crate_data(|cnum, data| {
918 if !needs_dep(data) {
922 info!("injecting a dep from {} to {}", cnum, krate);
923 data.add_dependency(krate);
927 fn report_unused_deps(&mut self, krate: &ast::Crate) {
928 // Make a point span rather than covering the whole file
929 let span = krate.span.shrink_to_lo();
930 // Complain about anything left over
931 for (name, entry) in self.sess.opts.externs.iter() {
932 if let ExternLocation::FoundInLibrarySearchDirectories = entry.location {
933 // Don't worry about pathless `--extern foo` sysroot references
936 let name_interned = Symbol::intern(name);
937 if self.used_extern_options.contains(&name_interned) {
941 // Got a real unused --extern
942 if self.sess.opts.json_unused_externs {
943 self.cstore.unused_externs.push(name_interned);
947 let diag = match self.sess.opts.extern_dep_specs.get(name) {
948 Some(loc) => BuiltinLintDiagnostics::ExternDepSpec(name.clone(), loc.into()),
950 // If we don't have a specific location, provide a json encoding of the `--extern`
952 let meta: BTreeMap<String, String> =
953 std::iter::once(("name".to_string(), name.to_string())).collect();
954 BuiltinLintDiagnostics::ExternDepSpec(
956 ExternDepSpec::Json(meta.to_json()),
960 self.sess.parse_sess.buffer_lint_with_diagnostic(
961 lint::builtin::UNUSED_CRATE_DEPENDENCIES,
965 "external crate `{}` unused in `{}`: remove the dependency or add `use {} as _;`",
967 self.local_crate_name,
974 pub fn postprocess(&mut self, krate: &ast::Crate) {
975 self.inject_profiler_runtime(krate);
976 self.inject_allocator_crate(krate);
977 self.inject_panic_runtime(krate);
979 self.report_unused_deps(krate);
981 info!("{:?}", CrateDump(&self.cstore));
984 pub fn process_extern_crate(
987 definitions: &Definitions,
991 ast::ItemKind::ExternCrate(orig_name) => {
993 "resolving extern crate stmt. ident: {} orig_name: {:?}",
994 item.ident, orig_name
996 let name = match orig_name {
998 validate_crate_name(self.sess, &orig_name.as_str(), Some(item.span));
1001 None => item.ident.name,
1003 let dep_kind = if self.sess.contains_name(&item.attrs, sym::no_link) {
1004 CrateDepKind::MacrosOnly
1006 CrateDepKind::Explicit
1009 let cnum = self.resolve_crate(name, item.span, dep_kind, None);
1011 let path_len = definitions.def_path(def_id).data.len();
1012 self.update_extern_crate(
1015 src: ExternCrateSource::Extern(def_id.to_def_id()),
1018 dependency_of: LOCAL_CRATE,
1027 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> CrateNum {
1028 let cnum = self.resolve_crate(name, span, CrateDepKind::Explicit, None);
1030 self.update_extern_crate(
1033 src: ExternCrateSource::Path,
1035 // to have the least priority in `update_extern_crate`
1036 path_len: usize::MAX,
1037 dependency_of: LOCAL_CRATE,
1044 pub fn maybe_process_path_extern(&mut self, name: Symbol) -> Option<CrateNum> {
1045 self.maybe_resolve_crate(name, CrateDepKind::Explicit, None).ok()
1049 fn global_allocator_spans(sess: &Session, krate: &ast::Crate) -> Vec<Span> {
1055 impl<'ast, 'a> visit::Visitor<'ast> for Finder<'a> {
1056 fn visit_item(&mut self, item: &'ast ast::Item) {
1057 if item.ident.name == self.name
1058 && self.sess.contains_name(&item.attrs, sym::rustc_std_internal_symbol)
1060 self.spans.push(item.span);
1062 visit::walk_item(self, item)
1066 let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::alloc));
1067 let mut f = Finder { sess, name, spans: Vec::new() };
1068 visit::walk_crate(&mut f, krate);