1 //! Validates all used crates and extern libraries and loads their metadata
3 use crate::locator::{CrateError, CrateLocator, CratePaths};
4 use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
6 use rustc_ast::expand::allocator::AllocatorKind;
7 use rustc_ast::{self as ast, *};
8 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
9 use rustc_data_structures::svh::Svh;
10 use rustc_data_structures::sync::Lrc;
11 use rustc_expand::base::SyntaxExtension;
12 use rustc_hir::def_id::{CrateNum, LocalDefId, StableCrateId, LOCAL_CRATE};
13 use rustc_hir::definitions::Definitions;
14 use rustc_index::vec::IndexVec;
15 use rustc_middle::ty::TyCtxt;
16 use rustc_serialize::json::ToJson;
17 use rustc_session::config::{self, CrateType, ExternLocation};
18 use rustc_session::cstore::{CrateDepKind, CrateSource, ExternCrate};
19 use rustc_session::cstore::{ExternCrateSource, MetadataLoaderDyn};
20 use rustc_session::lint::{self, BuiltinLintDiagnostics, ExternDepSpec};
21 use rustc_session::output::validate_crate_name;
22 use rustc_session::search_paths::PathKind;
23 use rustc_session::Session;
24 use rustc_span::edition::Edition;
25 use rustc_span::symbol::{sym, Symbol};
26 use rustc_span::{Span, DUMMY_SP};
27 use rustc_target::spec::{PanicStrategy, TargetTriple};
29 use proc_macro::bridge::client::ProcMacro;
30 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 pub(crate) 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 for (cnum, data) in self.0.iter_crate_data() {
106 writeln!(fmt, " name: {}", data.name())?;
107 writeln!(fmt, " cnum: {}", cnum)?;
108 writeln!(fmt, " hash: {}", data.hash())?;
109 writeln!(fmt, " reqd: {:?}", data.dep_kind())?;
110 let CrateSource { dylib, rlib, rmeta } = data.source();
111 if let Some(dylib) = dylib {
112 writeln!(fmt, " dylib: {}", dylib.0.display())?;
114 if let Some(rlib) = rlib {
115 writeln!(fmt, " rlib: {}", rlib.0.display())?;
117 if let Some(rmeta) = rmeta {
118 writeln!(fmt, " rmeta: {}", rmeta.0.display())?;
126 pub fn from_tcx(tcx: TyCtxt<'_>) -> &CStore {
127 tcx.cstore_untracked()
129 .downcast_ref::<CStore>()
130 .expect("`tcx.cstore` is not a `CStore`")
133 fn alloc_new_crate_num(&mut self) -> CrateNum {
134 self.metas.push(None);
135 CrateNum::new(self.metas.len() - 1)
138 crate fn get_crate_data(&self, cnum: CrateNum) -> CrateMetadataRef<'_> {
139 let cdata = self.metas[cnum]
141 .unwrap_or_else(|| panic!("Failed to get crate data for {:?}", cnum));
142 CrateMetadataRef { cdata, cstore: self }
145 fn set_crate_data(&mut self, cnum: CrateNum, data: CrateMetadata) {
146 assert!(self.metas[cnum].is_none(), "Overwriting crate metadata entry");
147 self.metas[cnum] = Some(Lrc::new(data));
150 crate fn iter_crate_data(&self) -> impl Iterator<Item = (CrateNum, &CrateMetadata)> {
153 .filter_map(|(cnum, data)| data.as_ref().map(|data| (cnum, &**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 for (cnum, _) in self.iter_crate_data() {
173 self.push_dependencies_in_postorder(&mut deps, cnum);
176 self.push_dependencies_in_postorder(&mut deps, cnum);
181 fn crate_dependencies_in_reverse_postorder(&self, cnum: CrateNum) -> Vec<CrateNum> {
182 let mut deps = self.crate_dependencies_in_postorder(cnum);
187 crate fn injected_panic_runtime(&self) -> Option<CrateNum> {
188 self.injected_panic_runtime
191 crate fn allocator_kind(&self) -> Option<AllocatorKind> {
195 crate fn has_global_allocator(&self) -> bool {
196 self.has_global_allocator
199 pub fn report_unused_deps(&self, tcx: TyCtxt<'_>) {
200 // We put the check for the option before the lint_level_at_node call
201 // because the call mutates internal state and introducing it
202 // leads to some ui tests failing.
203 if !tcx.sess.opts.json_unused_externs {
207 .lint_level_at_node(lint::builtin::UNUSED_CRATE_DEPENDENCIES, rustc_hir::CRATE_HIR_ID)
209 if level != lint::Level::Allow {
211 self.unused_externs.iter().map(|ident| ident.to_ident_string()).collect::<Vec<_>>();
212 let unused_externs = unused_externs.iter().map(String::as_str).collect::<Vec<&str>>();
216 .emit_unused_externs(level.as_str(), &unused_externs);
221 impl<'a> CrateLoader<'a> {
224 metadata_loader: Box<MetadataLoaderDyn>,
225 local_crate_name: &str,
227 let mut stable_crate_ids = FxHashMap::default();
228 stable_crate_ids.insert(sess.local_stable_crate_id(), LOCAL_CRATE);
233 local_crate_name: Symbol::intern(local_crate_name),
235 // We add an empty entry for LOCAL_CRATE (which maps to zero) in
236 // order to make array indices in `metas` match with the
237 // corresponding `CrateNum`. This first entry will always remain
239 metas: IndexVec::from_elem_n(None, 1),
240 injected_panic_runtime: None,
241 allocator_kind: None,
242 has_global_allocator: false,
244 unused_externs: Vec::new(),
246 used_extern_options: Default::default(),
250 pub fn cstore(&self) -> &CStore {
254 pub fn into_cstore(self) -> CStore {
258 fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
259 for (cnum, data) in self.cstore.iter_crate_data() {
260 if data.name() != name {
261 tracing::trace!("{} did not match {}", data.name(), name);
266 Some(hash) if hash == data.hash() => return Some(cnum),
268 debug!("actual hash {} did not match expected {}", hash, data.hash());
274 // When the hash is None we're dealing with a top-level dependency
275 // in which case we may have a specification on the command line for
276 // this library. Even though an upstream library may have loaded
277 // something of the same name, we have to make sure it was loaded
278 // from the exact same location as well.
280 // We're also sure to compare *paths*, not actual byte slices. The
281 // `source` stores paths which are normalized which may be different
282 // from the strings on the command line.
283 let source = self.cstore.get_crate_data(cnum).cdata.source();
284 if let Some(entry) = self.sess.opts.externs.get(name.as_str()) {
285 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
286 if let Some(mut files) = entry.files() {
288 let l = l.canonicalized();
289 source.dylib.as_ref().map(|(p, _)| p) == Some(l)
290 || source.rlib.as_ref().map(|(p, _)| p) == Some(l)
291 || source.rmeta.as_ref().map(|(p, _)| p) == Some(l)
299 // Alright, so we've gotten this far which means that `data` has the
300 // right name, we don't have a hash, and we don't have a --extern
301 // pointing for ourselves. We're still not quite yet done because we
302 // have to make sure that this crate was found in the crate lookup
303 // path (this is a top-level dependency) as we don't want to
304 // implicitly load anything inside the dependency lookup path.
305 let prev_kind = source
308 .or(source.rlib.as_ref())
309 .or(source.rmeta.as_ref())
310 .expect("No sources for crate")
312 if kind.matches(prev_kind) {
316 "failed to load existing crate {}; kind {:?} did not match prev_kind {:?}",
317 name, kind, prev_kind
325 fn verify_no_symbol_conflicts(&self, root: &CrateRoot<'_>) -> Result<(), CrateError> {
326 // Check for (potential) conflicts with the local crate
327 if self.sess.local_stable_crate_id() == root.stable_crate_id() {
328 return Err(CrateError::SymbolConflictsCurrent(root.name()));
331 // Check for conflicts with any crate loaded so far
332 for (_, other) in self.cstore.iter_crate_data() {
333 // Same stable crate id but different SVH
334 if other.stable_crate_id() == root.stable_crate_id() && other.hash() != root.hash() {
335 return Err(CrateError::SymbolConflictsOthers(root.name()));
342 fn verify_no_stable_crate_id_hash_conflicts(
344 root: &CrateRoot<'_>,
346 ) -> Result<(), CrateError> {
347 if let Some(existing) = self.cstore.stable_crate_ids.insert(root.stable_crate_id(), cnum) {
348 let crate_name0 = root.name();
349 let crate_name1 = self.cstore.get_crate_data(existing).name();
350 return Err(CrateError::StableCrateIdCollision(crate_name0, crate_name1));
358 host_lib: Option<Library>,
359 root: Option<&CratePaths>,
361 dep_kind: CrateDepKind,
363 ) -> Result<CrateNum, CrateError> {
364 let _prof_timer = self.sess.prof.generic_activity("metadata_register_crate");
366 let Library { source, metadata } = lib;
367 let crate_root = metadata.get_root();
368 let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
371 self.sess.opts.externs.get(name.as_str()).map_or(false, |e| e.is_private_dep);
373 // Claim this crate number and cache it
374 let cnum = self.cstore.alloc_new_crate_num();
377 "register crate `{}` (cnum = {}. private_dep = {})",
383 // Maintain a reference to the top most crate.
384 // Stash paths for top-most crate locally if necessary.
386 let root = if let Some(root) = root {
389 crate_paths = CratePaths::new(crate_root.name(), source.clone());
393 let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, dep_kind)?;
395 let raw_proc_macros = if crate_root.is_proc_macro_crate() {
397 let (dlsym_source, dlsym_root) = match &host_lib {
398 Some(host_lib) => (&host_lib.source, {
399 temp_root = host_lib.metadata.get_root();
402 None => (&source, &crate_root),
404 let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
405 Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.stable_crate_id())?)
410 // Perform some verification *after* resolve_crate_deps() above is
411 // known to have been successful. It seems that - in error cases - the
412 // cstore can be in a temporarily invalid state between cnum allocation
413 // and dependency resolution and the verification code would produce
414 // ICEs in that case (see #83045).
415 self.verify_no_symbol_conflicts(&crate_root)?;
416 self.verify_no_stable_crate_id_hash_conflicts(&crate_root, cnum)?;
418 let crate_metadata = CrateMetadata::new(
432 self.cstore.set_crate_data(cnum, crate_metadata);
437 fn load_proc_macro<'b>(
439 locator: &mut CrateLocator<'b>,
441 host_hash: Option<Svh>,
442 ) -> Result<Option<(LoadResult, Option<Library>)>, CrateError>
446 // Use a new crate locator so trying to load a proc macro doesn't affect the error
448 let mut proc_macro_locator = locator.clone();
450 // Try to load a proc macro
451 proc_macro_locator.is_proc_macro = true;
453 // Load the proc macro crate for the target
454 let (locator, target_result) = if self.sess.opts.debugging_opts.dual_proc_macros {
455 proc_macro_locator.reset();
456 let result = match self.load(&mut proc_macro_locator)? {
457 Some(LoadResult::Previous(cnum)) => {
458 return Ok(Some((LoadResult::Previous(cnum), None)));
460 Some(LoadResult::Loaded(library)) => Some(LoadResult::Loaded(library)),
461 None => return Ok(None),
463 locator.hash = host_hash;
464 // Use the locator when looking for the host proc macro crate, as that is required
465 // so we want it to affect the error message
468 (&mut proc_macro_locator, None)
471 // Load the proc macro crate for the host
474 locator.is_proc_macro = true;
475 locator.target = &self.sess.host;
476 locator.triple = TargetTriple::from_triple(config::host_triple());
477 locator.filesearch = self.sess.host_filesearch(path_kind);
479 let Some(host_result) = self.load(locator)? else {
483 Ok(Some(if self.sess.opts.debugging_opts.dual_proc_macros {
484 let host_result = match host_result {
485 LoadResult::Previous(..) => {
486 panic!("host and target proc macros must be loaded in lock-step")
488 LoadResult::Loaded(library) => library,
490 (target_result.unwrap(), Some(host_result))
496 fn resolve_crate<'b>(
500 dep_kind: CrateDepKind,
501 ) -> Option<CrateNum> {
502 self.used_extern_options.insert(name);
503 match self.maybe_resolve_crate(name, dep_kind, None) {
504 Ok(cnum) => Some(cnum),
507 self.maybe_resolve_crate(sym::core, CrateDepKind::Explicit, None).is_err();
508 err.report(&self.sess, span, missing_core);
514 fn maybe_resolve_crate<'b>(
517 mut dep_kind: CrateDepKind,
518 dep: Option<(&'b CratePaths, &'b CrateDep)>,
519 ) -> Result<CrateNum, CrateError> {
520 info!("resolving crate `{}`", name);
521 if !name.as_str().is_ascii() {
522 return Err(CrateError::NonAsciiName(name));
524 let (root, hash, host_hash, extra_filename, path_kind) = match dep {
525 Some((root, dep)) => (
529 Some(&dep.extra_filename[..]),
530 PathKind::Dependency,
532 None => (None, None, None, None, PathKind::Crate),
534 let result = if let Some(cnum) = self.existing_match(name, hash, path_kind) {
535 (LoadResult::Previous(cnum), None)
537 info!("falling back to a load");
538 let mut locator = CrateLocator::new(
540 &*self.metadata_loader,
548 match self.load(&mut locator)? {
549 Some(res) => (res, None),
551 dep_kind = CrateDepKind::MacrosOnly;
552 match self.load_proc_macro(&mut locator, path_kind, host_hash)? {
554 None => return Err(locator.into_error(root.cloned())),
561 (LoadResult::Previous(cnum), None) => {
562 let data = self.cstore.get_crate_data(cnum);
563 if data.is_proc_macro_crate() {
564 dep_kind = CrateDepKind::MacrosOnly;
566 data.update_dep_kind(|data_dep_kind| cmp::max(data_dep_kind, dep_kind));
569 (LoadResult::Loaded(library), host_library) => {
570 self.register_crate(host_library, root, library, dep_kind, name)
576 fn load(&self, locator: &mut CrateLocator<'_>) -> Result<Option<LoadResult>, CrateError> {
577 let Some(library) = locator.maybe_load_library_crate()? else {
581 // In the case that we're loading a crate, but not matching
582 // against a hash, we could load a crate which has the same hash
583 // as an already loaded crate. If this is the case prevent
584 // duplicates by just using the first crate.
586 // Note that we only do this for target triple crates, though, as we
587 // don't want to match a host crate against an equivalent target one
589 let root = library.metadata.get_root();
590 // FIXME: why is this condition necessary? It was adding in #33625 but I
591 // don't know why and the original author doesn't remember ...
592 let can_reuse_cratenum =
593 locator.triple == self.sess.opts.target_triple || locator.is_proc_macro;
594 Ok(Some(if can_reuse_cratenum {
595 let mut result = LoadResult::Loaded(library);
596 for (cnum, data) in self.cstore.iter_crate_data() {
597 if data.name() == root.name() && root.hash() == data.hash() {
598 assert!(locator.hash.is_none());
599 info!("load success, going to previous cnum: {}", cnum);
600 result = LoadResult::Previous(cnum);
606 LoadResult::Loaded(library)
610 fn update_extern_crate(&self, cnum: CrateNum, extern_crate: ExternCrate) {
611 let cmeta = self.cstore.get_crate_data(cnum);
612 if cmeta.update_extern_crate(extern_crate) {
613 // Propagate the extern crate info to dependencies if it was updated.
614 let extern_crate = ExternCrate { dependency_of: cnum, ..extern_crate };
615 for &dep_cnum in cmeta.dependencies().iter() {
616 self.update_extern_crate(dep_cnum, extern_crate);
621 // Go through the crate metadata and load any crates that it references
622 fn resolve_crate_deps(
625 crate_root: &CrateRoot<'_>,
626 metadata: &MetadataBlob,
628 dep_kind: CrateDepKind,
629 ) -> Result<CrateNumMap, CrateError> {
630 debug!("resolving deps of external crate");
631 if crate_root.is_proc_macro_crate() {
632 return Ok(CrateNumMap::new());
635 // The map from crate numbers in the crate we're resolving to local crate numbers.
636 // We map 0 and all other holes in the map to our parent crate. The "additional"
637 // self-dependencies should be harmless.
638 let deps = crate_root.decode_crate_deps(metadata);
639 let mut crate_num_map = CrateNumMap::with_capacity(1 + deps.len());
640 crate_num_map.push(krate);
643 "resolving dep crate {} hash: `{}` extra filename: `{}`",
644 dep.name, dep.hash, dep.extra_filename
646 let dep_kind = match dep_kind {
647 CrateDepKind::MacrosOnly => CrateDepKind::MacrosOnly,
650 let cnum = self.maybe_resolve_crate(dep.name, dep_kind, Some((root, &dep)))?;
651 crate_num_map.push(cnum);
654 debug!("resolve_crate_deps: cnum_map for {:?} is {:?}", krate, crate_num_map);
658 fn dlsym_proc_macros(
661 stable_crate_id: StableCrateId,
662 ) -> Result<&'static [ProcMacro], CrateError> {
663 // Make sure the path contains a / or the linker will search for it.
664 let path = env::current_dir().unwrap().join(path);
665 let lib = unsafe { libloading::Library::new(path) }
666 .map_err(|err| CrateError::DlOpen(err.to_string()))?;
668 let sym_name = self.sess.generate_proc_macro_decls_symbol(stable_crate_id);
669 let sym = unsafe { lib.get::<*const &[ProcMacro]>(sym_name.as_bytes()) }
670 .map_err(|err| CrateError::DlSym(err.to_string()))?;
672 // Intentionally leak the dynamic library. We can't ever unload it
673 // since the library can make things that will live arbitrarily long.
674 let sym = unsafe { sym.into_raw() };
675 std::mem::forget(lib);
680 fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
681 // If we're only compiling an rlib, then there's no need to select a
682 // panic runtime, so we just skip this section entirely.
683 let any_non_rlib = self.sess.crate_types().iter().any(|ct| *ct != CrateType::Rlib);
685 info!("panic runtime injection skipped, only generating rlib");
689 // If we need a panic runtime, we try to find an existing one here. At
690 // the same time we perform some general validation of the DAG we've got
691 // going such as ensuring everything has a compatible panic strategy.
693 // The logic for finding the panic runtime here is pretty much the same
694 // as the allocator case with the only addition that the panic strategy
695 // compilation mode also comes into play.
696 let desired_strategy = self.sess.panic_strategy();
697 let mut runtime_found = false;
698 let mut needs_panic_runtime =
699 self.sess.contains_name(&krate.attrs, sym::needs_panic_runtime);
701 for (cnum, data) in self.cstore.iter_crate_data() {
702 needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
703 if data.is_panic_runtime() {
704 // Inject a dependency from all #![needs_panic_runtime] to this
705 // #![panic_runtime] crate.
706 self.inject_dependency_if(cnum, "a panic runtime", &|data| {
707 data.needs_panic_runtime()
709 runtime_found = runtime_found || data.dep_kind() == CrateDepKind::Explicit;
713 // If an explicitly linked and matching panic runtime was found, or if
714 // we just don't need one at all, then we're done here and there's
715 // nothing else to do.
716 if !needs_panic_runtime || runtime_found {
720 // By this point we know that we (a) need a panic runtime and (b) no
721 // panic runtime was explicitly linked. Here we just load an appropriate
722 // default runtime for our panic strategy and then inject the
725 // We may resolve to an already loaded crate (as the crate may not have
726 // been explicitly linked prior to this) and we may re-inject
727 // dependencies again, but both of those situations are fine.
729 // Also note that we have yet to perform validation of the crate graph
730 // in terms of everyone has a compatible panic runtime format, that's
731 // performed later as part of the `dependency_format` module.
732 let name = match desired_strategy {
733 PanicStrategy::Unwind => sym::panic_unwind,
734 PanicStrategy::Abort => sym::panic_abort,
736 info!("panic runtime not found -- loading {}", name);
738 let Some(cnum) = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit) else { return; };
739 let data = self.cstore.get_crate_data(cnum);
741 // Sanity check the loaded crate to ensure it is indeed a panic runtime
742 // and the panic strategy is indeed what we thought it was.
743 if !data.is_panic_runtime() {
744 self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
746 if data.panic_strategy() != desired_strategy {
747 self.sess.err(&format!(
748 "the crate `{}` does not have the panic \
751 desired_strategy.desc()
755 self.cstore.injected_panic_runtime = Some(cnum);
756 self.inject_dependency_if(cnum, "a panic runtime", &|data| data.needs_panic_runtime());
759 fn inject_profiler_runtime(&mut self, krate: &ast::Crate) {
760 if self.sess.opts.debugging_opts.no_profiler_runtime
761 || !(self.sess.instrument_coverage()
762 || self.sess.opts.debugging_opts.profile
763 || self.sess.opts.cg.profile_generate.enabled())
768 info!("loading profiler");
770 let name = Symbol::intern(&self.sess.opts.debugging_opts.profiler_runtime);
771 if name == sym::profiler_builtins && self.sess.contains_name(&krate.attrs, sym::no_core) {
773 "`profiler_builtins` crate (required by compiler options) \
774 is not compatible with crate attribute `#![no_core]`",
778 let Some(cnum) = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit) else { return; };
779 let data = self.cstore.get_crate_data(cnum);
781 // Sanity check the loaded crate to ensure it is indeed a profiler runtime
782 if !data.is_profiler_runtime() {
783 self.sess.err(&format!("the crate `{}` is not a profiler runtime", name));
787 fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
788 self.cstore.has_global_allocator = match &*global_allocator_spans(&self.sess, krate) {
789 [span1, span2, ..] => {
791 .struct_span_err(*span2, "cannot define multiple global allocators")
792 .span_label(*span2, "cannot define a new global allocator")
793 .span_label(*span1, "previous global allocator defined here")
797 spans => !spans.is_empty(),
800 // Check to see if we actually need an allocator. This desire comes
801 // about through the `#![needs_allocator]` attribute and is typically
802 // written down in liballoc.
803 if !self.sess.contains_name(&krate.attrs, sym::needs_allocator)
804 && !self.cstore.iter_crate_data().any(|(_, data)| data.needs_allocator())
809 // At this point we've determined that we need an allocator. Let's see
810 // if our compilation session actually needs an allocator based on what
812 let all_rlib = self.sess.crate_types().iter().all(|ct| matches!(*ct, CrateType::Rlib));
817 // Ok, we need an allocator. Not only that but we're actually going to
818 // create an artifact that needs one linked in. Let's go find the one
819 // that we're going to link in.
821 // First up we check for global allocators. Look at the crate graph here
822 // and see what's a global allocator, including if we ourselves are a
824 let mut global_allocator =
825 self.cstore.has_global_allocator.then(|| Symbol::intern("this crate"));
826 for (_, data) in self.cstore.iter_crate_data() {
827 if data.has_global_allocator() {
828 match global_allocator {
829 Some(other_crate) => {
830 self.sess.err(&format!(
831 "the `#[global_allocator]` in {} conflicts with global allocator in: {}",
836 None => global_allocator = Some(data.name()),
841 if global_allocator.is_some() {
842 self.cstore.allocator_kind = Some(AllocatorKind::Global);
846 // Ok we haven't found a global allocator but we still need an
847 // allocator. At this point our allocator request is typically fulfilled
848 // by the standard library, denoted by the `#![default_lib_allocator]`
850 if !self.sess.contains_name(&krate.attrs, sym::default_lib_allocator)
851 && !self.cstore.iter_crate_data().any(|(_, data)| data.has_default_lib_allocator())
854 "no global memory allocator found but one is required; link to std or add \
855 `#[global_allocator]` to a static item that implements the GlobalAlloc trait",
858 self.cstore.allocator_kind = Some(AllocatorKind::Default);
861 fn inject_dependency_if(
865 needs_dep: &dyn Fn(&CrateMetadata) -> bool,
867 // don't perform this validation if the session has errors, as one of
868 // those errors may indicate a circular dependency which could cause
869 // this to stack overflow.
870 if self.sess.has_errors().is_some() {
874 // Before we inject any dependencies, make sure we don't inject a
875 // circular dependency by validating that this crate doesn't
876 // transitively depend on any crates satisfying `needs_dep`.
877 for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
878 let data = self.cstore.get_crate_data(dep);
879 if needs_dep(&data) {
880 self.sess.err(&format!(
881 "the crate `{}` cannot depend \
882 on a crate that needs {}, but \
884 self.cstore.get_crate_data(krate).name(),
891 // All crates satisfying `needs_dep` do not explicitly depend on the
892 // crate provided for this compile, but in order for this compilation to
893 // be successfully linked we need to inject a dependency (to order the
894 // crates on the command line correctly).
895 for (cnum, data) in self.cstore.iter_crate_data() {
897 info!("injecting a dep from {} to {}", cnum, krate);
898 data.add_dependency(krate);
903 fn report_unused_deps(&mut self, krate: &ast::Crate) {
904 // Make a point span rather than covering the whole file
905 let span = krate.spans.inner_span.shrink_to_lo();
906 // Complain about anything left over
907 for (name, entry) in self.sess.opts.externs.iter() {
908 if let ExternLocation::FoundInLibrarySearchDirectories = entry.location {
909 // Don't worry about pathless `--extern foo` sysroot references
912 let name_interned = Symbol::intern(name);
913 if self.used_extern_options.contains(&name_interned) {
917 // Got a real unused --extern
918 if self.sess.opts.json_unused_externs {
919 self.cstore.unused_externs.push(name_interned);
923 let diag = match self.sess.opts.extern_dep_specs.get(name) {
924 Some(loc) => BuiltinLintDiagnostics::ExternDepSpec(name.clone(), loc.into()),
926 // If we don't have a specific location, provide a json encoding of the `--extern`
928 let meta: BTreeMap<String, String> =
929 std::iter::once(("name".to_string(), name.to_string())).collect();
930 BuiltinLintDiagnostics::ExternDepSpec(
932 ExternDepSpec::Json(meta.to_json()),
936 self.sess.parse_sess.buffer_lint_with_diagnostic(
937 lint::builtin::UNUSED_CRATE_DEPENDENCIES,
941 "external crate `{}` unused in `{}`: remove the dependency or add `use {} as _;`",
943 self.local_crate_name,
950 pub fn postprocess(&mut self, krate: &ast::Crate) {
951 self.inject_profiler_runtime(krate);
952 self.inject_allocator_crate(krate);
953 self.inject_panic_runtime(krate);
955 self.report_unused_deps(krate);
957 info!("{:?}", CrateDump(&self.cstore));
960 pub fn process_extern_crate(
963 definitions: &Definitions,
965 ) -> Option<CrateNum> {
967 ast::ItemKind::ExternCrate(orig_name) => {
969 "resolving extern crate stmt. ident: {} orig_name: {:?}",
970 item.ident, orig_name
972 let name = match orig_name {
974 validate_crate_name(self.sess, orig_name.as_str(), Some(item.span));
977 None => item.ident.name,
979 let dep_kind = if self.sess.contains_name(&item.attrs, sym::no_link) {
980 CrateDepKind::MacrosOnly
982 CrateDepKind::Explicit
985 let cnum = self.resolve_crate(name, item.span, dep_kind)?;
987 let path_len = definitions.def_path(def_id).data.len();
988 self.update_extern_crate(
991 src: ExternCrateSource::Extern(def_id.to_def_id()),
994 dependency_of: LOCAL_CRATE,
1003 pub fn process_path_extern(&mut self, name: Symbol, span: Span) -> Option<CrateNum> {
1004 let cnum = self.resolve_crate(name, span, CrateDepKind::Explicit)?;
1006 self.update_extern_crate(
1009 src: ExternCrateSource::Path,
1011 // to have the least priority in `update_extern_crate`
1012 path_len: usize::MAX,
1013 dependency_of: LOCAL_CRATE,
1020 pub fn maybe_process_path_extern(&mut self, name: Symbol) -> Option<CrateNum> {
1021 self.maybe_resolve_crate(name, CrateDepKind::Explicit, None).ok()
1025 fn global_allocator_spans(sess: &Session, krate: &ast::Crate) -> Vec<Span> {
1031 impl<'ast, 'a> visit::Visitor<'ast> for Finder<'a> {
1032 fn visit_item(&mut self, item: &'ast ast::Item) {
1033 if item.ident.name == self.name
1034 && self.sess.contains_name(&item.attrs, sym::rustc_std_internal_symbol)
1036 self.spans.push(item.span);
1038 visit::walk_item(self, item)
1042 let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::alloc));
1043 let mut f = Finder { sess, name, spans: Vec::new() };
1044 visit::walk_crate(&mut f, krate);