1 //! Finds crate binaries and loads their metadata
3 //! Might I be the first to welcome you to a world of platform differences,
4 //! version requirements, dependency graphs, conflicting desires, and fun! This
5 //! is the major guts (along with metadata::creader) of the compiler for loading
6 //! crates and resolving dependencies. Let's take a tour!
10 //! Each invocation of the compiler is immediately concerned with one primary
11 //! problem, to connect a set of crates to resolved crates on the filesystem.
12 //! Concretely speaking, the compiler follows roughly these steps to get here:
14 //! 1. Discover a set of `extern crate` statements.
15 //! 2. Transform these directives into crate names. If the directive does not
16 //! have an explicit name, then the identifier is the name.
17 //! 3. For each of these crate names, find a corresponding crate on the
20 //! Sounds easy, right? Let's walk into some of the nuances.
22 //! ## Transitive Dependencies
24 //! Let's say we've got three crates: A, B, and C. A depends on B, and B depends
25 //! on C. When we're compiling A, we primarily need to find and locate B, but we
26 //! also end up needing to find and locate C as well.
28 //! The reason for this is that any of B's types could be composed of C's types,
29 //! any function in B could return a type from C, etc. To be able to guarantee
30 //! that we can always type-check/translate any function, we have to have
31 //! complete knowledge of the whole ecosystem, not just our immediate
34 //! So now as part of the "find a corresponding crate on the filesystem" step
35 //! above, this involves also finding all crates for *all upstream
36 //! dependencies*. This includes all dependencies transitively.
38 //! ## Rlibs and Dylibs
40 //! The compiler has two forms of intermediate dependencies. These are dubbed
41 //! rlibs and dylibs for the static and dynamic variants, respectively. An rlib
42 //! is a rustc-defined file format (currently just an ar archive) while a dylib
43 //! is a platform-defined dynamic library. Each library has a metadata somewhere
46 //! A third kind of dependency is an rmeta file. These are metadata files and do
47 //! not contain any code, etc. To a first approximation, these are treated in the
48 //! same way as rlibs. Where there is both an rlib and an rmeta file, the rlib
49 //! gets priority (even if the rmeta file is newer). An rmeta file is only
50 //! useful for checking a downstream crate, attempting to link one will cause an
53 //! When translating a crate name to a crate on the filesystem, we all of a
54 //! sudden need to take into account both rlibs and dylibs! Linkage later on may
55 //! use either one of these files, as each has their pros/cons. The job of crate
56 //! loading is to discover what's possible by finding all candidates.
58 //! Most parts of this loading systems keep the dylib/rlib as just separate
63 //! We can't exactly scan your whole hard drive when looking for dependencies,
64 //! so we need to places to look. Currently the compiler will implicitly add the
65 //! target lib search path ($prefix/lib/rustlib/$target/lib) to any compilation,
66 //! and otherwise all -L flags are added to the search paths.
68 //! ## What criterion to select on?
70 //! This is a pretty tricky area of loading crates. Given a file, how do we know
71 //! whether it's the right crate? Currently, the rules look along these lines:
73 //! 1. Does the filename match an rlib/dylib pattern? That is to say, does the
74 //! filename have the right prefix/suffix?
75 //! 2. Does the filename have the right prefix for the crate name being queried?
76 //! This is filtering for files like `libfoo*.rlib` and such. If the crate
77 //! we're looking for was originally compiled with -C extra-filename, the
78 //! extra filename will be included in this prefix to reduce reading
79 //! metadata from crates that would otherwise share our prefix.
80 //! 3. Is the file an actual rust library? This is done by loading the metadata
81 //! from the library and making sure it's actually there.
82 //! 4. Does the name in the metadata agree with the name of the library?
83 //! 5. Does the target in the metadata agree with the current target?
84 //! 6. Does the SVH match? (more on this later)
86 //! If the file answers `yes` to all these questions, then the file is
87 //! considered as being *candidate* for being accepted. It is illegal to have
88 //! more than two candidates as the compiler has no method by which to resolve
89 //! this conflict. Additionally, rlib/dylib candidates are considered
92 //! After all this has happened, we have 1 or two files as candidates. These
93 //! represent the rlib/dylib file found for a library, and they're returned as
96 //! ### What about versions?
98 //! A lot of effort has been put forth to remove versioning from the compiler.
99 //! There have been forays in the past to have versioning baked in, but it was
100 //! largely always deemed insufficient to the point that it was recognized that
101 //! it's probably something the compiler shouldn't do anyway due to its
102 //! complicated nature and the state of the half-baked solutions.
104 //! With a departure from versioning, the primary criterion for loading crates
105 //! is just the name of a crate. If we stopped here, it would imply that you
106 //! could never link two crates of the same name from different sources
107 //! together, which is clearly a bad state to be in.
109 //! To resolve this problem, we come to the next section!
113 //! A number of flags have been added to the compiler to solve the "version
114 //! problem" in the previous section, as well as generally enabling more
115 //! powerful usage of the crate loading system of the compiler. The goal of
116 //! these flags and options are to enable third-party tools to drive the
117 //! compiler with prior knowledge about how the world should look.
119 //! ## The `--extern` flag
121 //! The compiler accepts a flag of this form a number of times:
124 //! --extern crate-name=path/to/the/crate.rlib
127 //! This flag is basically the following letter to the compiler:
131 //! > When you are attempting to load the immediate dependency `crate-name`, I
132 //! > would like you to assume that the library is located at
133 //! > `path/to/the/crate.rlib`, and look nowhere else. Also, please do not
134 //! > assume that the path I specified has the name `crate-name`.
136 //! This flag basically overrides most matching logic except for validating that
137 //! the file is indeed a rust library. The same `crate-name` can be specified
138 //! twice to specify the rlib/dylib pair.
140 //! ## Enabling "multiple versions"
142 //! This basically boils down to the ability to specify arbitrary packages to
143 //! the compiler. For example, if crate A wanted to use Bv1 and Bv2, then it
144 //! would look something like:
146 //! ```compile_fail,E0463
153 //! and the compiler would be invoked as:
156 //! rustc a.rs --extern b1=path/to/libb1.rlib --extern b2=path/to/libb2.rlib
159 //! In this scenario there are two crates named `b` and the compiler must be
160 //! manually driven to be informed where each crate is.
162 //! ## Frobbing symbols
164 //! One of the immediate problems with linking the same library together twice
165 //! in the same problem is dealing with duplicate symbols. The primary way to
166 //! deal with this in rustc is to add hashes to the end of each symbol.
168 //! In order to force hashes to change between versions of a library, if
169 //! desired, the compiler exposes an option `-C metadata=foo`, which is used to
170 //! initially seed each symbol hash. The string `foo` is prepended to each
171 //! string-to-hash to ensure that symbols change over time.
173 //! ## Loading transitive dependencies
175 //! Dealing with same-named-but-distinct crates is not just a local problem, but
176 //! one that also needs to be dealt with for transitive dependencies. Note that
177 //! in the letter above `--extern` flags only apply to the *local* set of
178 //! dependencies, not the upstream transitive dependencies. Consider this
179 //! dependency graph:
191 //! In this scenario, when we compile `D`, we need to be able to distinctly
192 //! resolve `A.1` and `A.2`, but an `--extern` flag cannot apply to these
193 //! transitive dependencies.
195 //! Note that the key idea here is that `B` and `C` are both *already compiled*.
196 //! That is, they have already resolved their dependencies. Due to unrelated
197 //! technical reasons, when a library is compiled, it is only compatible with
198 //! the *exact same* version of the upstream libraries it was compiled against.
199 //! We use the "Strict Version Hash" to identify the exact copy of an upstream
202 //! With this knowledge, we know that `B` and `C` will depend on `A` with
203 //! different SVH values, so we crawl the normal `-L` paths looking for
204 //! `liba*.rlib` and filter based on the contained SVH.
206 //! In the end, this ends up not needing `--extern` to specify upstream
207 //! transitive dependencies.
211 //! That's the general overview of loading crates in the compiler, but it's by
212 //! no means all of the necessary details. Take a look at the rest of
213 //! metadata::locator or metadata::creader for all the juicy details!
215 use crate::creader::Library;
217 CannotFindCrate, CrateLocationUnknownType, DlError, ExternLocationNotExist,
218 ExternLocationNotFile, FoundStaticlib, IncompatibleRustc, InvalidMetadataFiles,
219 LibFilenameForm, MultipleCandidates, NewerCrateVersion, NoCrateWithTriple, NoDylibPlugin,
220 NonAsciiName, StableCrateIdCollision, SymbolConflictsCurrent, SymbolConflictsOthers,
222 use crate::rmeta::{rustc_version, MetadataBlob, METADATA_HEADER};
224 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
225 use rustc_data_structures::memmap::Mmap;
226 use rustc_data_structures::owning_ref::OwningRef;
227 use rustc_data_structures::svh::Svh;
228 use rustc_data_structures::sync::MetadataRef;
229 use rustc_errors::{DiagnosticArgValue, FatalError, IntoDiagnosticArg};
230 use rustc_session::config::{self, CrateType};
231 use rustc_session::cstore::{CrateSource, MetadataLoader};
232 use rustc_session::filesearch::FileSearch;
233 use rustc_session::search_paths::PathKind;
234 use rustc_session::utils::CanonicalizedPath;
235 use rustc_session::Session;
236 use rustc_span::symbol::Symbol;
237 use rustc_span::Span;
238 use rustc_target::spec::{Target, TargetTriple};
240 use snap::read::FrameDecoder;
241 use std::borrow::Cow;
242 use std::io::{Read, Result as IoResult, Write};
243 use std::path::{Path, PathBuf};
244 use std::{cmp, fmt, fs};
247 pub(crate) struct CrateLocator<'a> {
248 // Immutable per-session configuration.
249 only_needs_metadata: bool,
251 metadata_loader: &'a dyn MetadataLoader,
253 // Immutable per-search configuration.
255 exact_paths: Vec<CanonicalizedPath>,
256 pub hash: Option<Svh>,
257 extra_filename: Option<&'a str>,
258 pub target: &'a Target,
259 pub triple: TargetTriple,
260 pub filesearch: FileSearch<'a>,
261 pub is_proc_macro: bool,
263 // Mutable in-progress state or output.
264 crate_rejections: CrateRejections,
268 pub(crate) struct CratePaths {
274 pub(crate) fn new(name: Symbol, source: CrateSource) -> CratePaths {
275 CratePaths { name, source }
279 #[derive(Copy, Clone, PartialEq)]
280 pub(crate) enum CrateFlavor {
286 impl fmt::Display for CrateFlavor {
287 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
288 f.write_str(match *self {
289 CrateFlavor::Rlib => "rlib",
290 CrateFlavor::Rmeta => "rmeta",
291 CrateFlavor::Dylib => "dylib",
296 impl IntoDiagnosticArg for CrateFlavor {
297 fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
299 CrateFlavor::Rlib => DiagnosticArgValue::Str(Cow::Borrowed("rlib")),
300 CrateFlavor::Rmeta => DiagnosticArgValue::Str(Cow::Borrowed("rmeta")),
301 CrateFlavor::Dylib => DiagnosticArgValue::Str(Cow::Borrowed("dylib")),
306 impl<'a> CrateLocator<'a> {
309 metadata_loader: &'a dyn MetadataLoader,
312 extra_filename: Option<&'a str>,
315 ) -> CrateLocator<'a> {
316 // The all loop is because `--crate-type=rlib --crate-type=rlib` is
317 // legal and produces both inside this type.
318 let is_rlib = sess.crate_types().iter().all(|c| *c == CrateType::Rlib);
319 let needs_object_code = sess.opts.output_types.should_codegen();
320 // If we're producing an rlib, then we don't need object code.
321 // Or, if we're not producing object code, then we don't need it either
322 // (e.g., if we're a cdylib but emitting just metadata).
323 let only_needs_metadata = is_rlib || !needs_object_code;
327 sysroot: &sess.sysroot,
330 exact_paths: if hash.is_none() {
333 .get(crate_name.as_str())
335 .filter_map(|entry| entry.files())
340 // SVH being specified means this is a transitive dependency,
341 // so `--extern` options do not apply.
346 target: if is_host { &sess.host } else { &sess.target },
348 TargetTriple::from_triple(config::host_triple())
350 sess.opts.target_triple.clone()
352 filesearch: if is_host {
353 sess.host_filesearch(path_kind)
355 sess.target_filesearch(path_kind)
357 is_proc_macro: false,
358 crate_rejections: CrateRejections::default(),
362 pub(crate) fn reset(&mut self) {
363 self.crate_rejections.via_hash.clear();
364 self.crate_rejections.via_triple.clear();
365 self.crate_rejections.via_kind.clear();
366 self.crate_rejections.via_version.clear();
367 self.crate_rejections.via_filename.clear();
368 self.crate_rejections.via_invalid.clear();
371 pub(crate) fn maybe_load_library_crate(&mut self) -> Result<Option<Library>, CrateError> {
372 if !self.exact_paths.is_empty() {
373 return self.find_commandline_library();
375 let mut seen_paths = FxHashSet::default();
376 if let Some(extra_filename) = self.extra_filename {
377 if let library @ Some(_) = self.find_library_crate(extra_filename, &mut seen_paths)? {
381 self.find_library_crate("", &mut seen_paths)
384 fn find_library_crate(
387 seen_paths: &mut FxHashSet<PathBuf>,
388 ) -> Result<Option<Library>, CrateError> {
389 let rmeta_prefix = &format!("lib{}{}", self.crate_name, extra_prefix);
390 let rlib_prefix = rmeta_prefix;
392 &format!("{}{}{}", self.target.dll_prefix, self.crate_name, extra_prefix);
393 let staticlib_prefix =
394 &format!("{}{}{}", self.target.staticlib_prefix, self.crate_name, extra_prefix);
396 let rmeta_suffix = ".rmeta";
397 let rlib_suffix = ".rlib";
398 let dylib_suffix = &self.target.dll_suffix;
399 let staticlib_suffix = &self.target.staticlib_suffix;
401 let mut candidates: FxHashMap<_, (FxHashMap<_, _>, FxHashMap<_, _>, FxHashMap<_, _>)> =
404 // First, find all possible candidate rlibs and dylibs purely based on
405 // the name of the files themselves. We're trying to match against an
406 // exact crate name and a possibly an exact hash.
408 // During this step, we can filter all found libraries based on the
409 // name and id found in the crate id (we ignore the path portion for
410 // filename matching), as well as the exact hash (if specified). If we
411 // end up having many candidates, we must look at the metadata to
412 // perform exact matches against hashes/crate ids. Note that opening up
413 // the metadata is where we do an exact match against the full contents
414 // of the crate id (path/name/id).
416 // The goal of this step is to look at as little metadata as possible.
417 // Unfortunately, the prefix-based matching sometimes is over-eager.
418 // E.g. if `rlib_suffix` is `libstd` it'll match the file
419 // `libstd_detect-8d6701fb958915ad.rlib` (incorrect) as well as
420 // `libstd-f3ab5b1dea981f17.rlib` (correct). But this is hard to avoid
421 // given that `extra_filename` comes from the `-C extra-filename`
422 // option and thus can be anything, and the incorrect match will be
423 // handled safely in `extract_one`.
424 for search_path in self.filesearch.search_paths() {
425 debug!("searching {}", search_path.dir.display());
426 for spf in search_path.files.iter() {
427 debug!("testing {}", spf.path.display());
429 let f = &spf.file_name_str;
430 let (hash, kind) = if f.starts_with(rlib_prefix) && f.ends_with(rlib_suffix) {
431 (&f[rlib_prefix.len()..(f.len() - rlib_suffix.len())], CrateFlavor::Rlib)
432 } else if f.starts_with(rmeta_prefix) && f.ends_with(rmeta_suffix) {
433 (&f[rmeta_prefix.len()..(f.len() - rmeta_suffix.len())], CrateFlavor::Rmeta)
434 } else if f.starts_with(dylib_prefix) && f.ends_with(dylib_suffix.as_ref()) {
435 (&f[dylib_prefix.len()..(f.len() - dylib_suffix.len())], CrateFlavor::Dylib)
437 if f.starts_with(staticlib_prefix) && f.ends_with(staticlib_suffix.as_ref()) {
438 self.crate_rejections.via_kind.push(CrateMismatch {
439 path: spf.path.clone(),
440 got: "static".to_string(),
446 info!("lib candidate: {}", spf.path.display());
448 let (rlibs, rmetas, dylibs) = candidates.entry(hash.to_string()).or_default();
449 let path = fs::canonicalize(&spf.path).unwrap_or_else(|_| spf.path.clone());
450 if seen_paths.contains(&path) {
453 seen_paths.insert(path.clone());
455 CrateFlavor::Rlib => rlibs.insert(path, search_path.kind),
456 CrateFlavor::Rmeta => rmetas.insert(path, search_path.kind),
457 CrateFlavor::Dylib => dylibs.insert(path, search_path.kind),
462 // We have now collected all known libraries into a set of candidates
463 // keyed of the filename hash listed. For each filename, we also have a
464 // list of rlibs/dylibs that apply. Here, we map each of these lists
465 // (per hash), to a Library candidate for returning.
467 // A Library candidate is created if the metadata for the set of
468 // libraries corresponds to the crate id and hash criteria that this
469 // search is being performed for.
470 let mut libraries = FxHashMap::default();
471 for (_hash, (rlibs, rmetas, dylibs)) in candidates {
472 if let Some((svh, lib)) = self.extract_lib(rlibs, rmetas, dylibs)? {
473 libraries.insert(svh, lib);
477 // Having now translated all relevant found hashes into libraries, see
478 // what we've got and figure out if we found multiple candidates for
480 match libraries.len() {
482 1 => Ok(Some(libraries.into_iter().next().unwrap().1)),
484 let mut libraries: Vec<_> = libraries.into_values().collect();
486 libraries.sort_by_cached_key(|lib| lib.source.paths().next().unwrap().clone());
487 let candidates = libraries
489 .map(|lib| lib.source.paths().next().unwrap().clone())
490 .collect::<Vec<_>>();
492 Err(CrateError::MultipleCandidates(
494 // these are the same for all candidates
495 get_flavor_from_path(candidates.first().unwrap()),
504 rlibs: FxHashMap<PathBuf, PathKind>,
505 rmetas: FxHashMap<PathBuf, PathKind>,
506 dylibs: FxHashMap<PathBuf, PathKind>,
507 ) -> Result<Option<(Svh, Library)>, CrateError> {
509 // Order here matters, rmeta should come first. See comment in
510 // `extract_one` below.
511 let source = CrateSource {
512 rmeta: self.extract_one(rmetas, CrateFlavor::Rmeta, &mut slot)?,
513 rlib: self.extract_one(rlibs, CrateFlavor::Rlib, &mut slot)?,
514 dylib: self.extract_one(dylibs, CrateFlavor::Dylib, &mut slot)?,
516 Ok(slot.map(|(svh, metadata)| (svh, Library { source, metadata })))
519 fn needs_crate_flavor(&self, flavor: CrateFlavor) -> bool {
520 if flavor == CrateFlavor::Dylib && self.is_proc_macro {
524 if self.only_needs_metadata {
525 flavor == CrateFlavor::Rmeta
527 // we need all flavors (perhaps not true, but what we do for now)
532 // Attempts to extract *one* library from the set `m`. If the set has no
533 // elements, `None` is returned. If the set has more than one element, then
534 // the errors and notes are emitted about the set of libraries.
536 // With only one library in the set, this function will extract it, and then
537 // read the metadata from it if `*slot` is `None`. If the metadata couldn't
538 // be read, it is assumed that the file isn't a valid rust library (no
539 // errors are emitted).
542 m: FxHashMap<PathBuf, PathKind>,
544 slot: &mut Option<(Svh, MetadataBlob)>,
545 ) -> Result<Option<(PathBuf, PathKind)>, CrateError> {
546 // If we are producing an rlib, and we've already loaded metadata, then
547 // we should not attempt to discover further crate sources (unless we're
548 // locating a proc macro; exact logic is in needs_crate_flavor). This means
549 // that under -Zbinary-dep-depinfo we will not emit a dependency edge on
550 // the *unused* rlib, and by returning `None` here immediately we
551 // guarantee that we do indeed not use it.
553 // See also #68149 which provides more detail on why emitting the
554 // dependency on the rlib is a bad thing.
556 // We currently do not verify that these other sources are even in sync,
557 // and this is arguably a bug (see #10786), but because reading metadata
558 // is quite slow (especially from dylibs) we currently do not read it
559 // from the other crate sources.
561 if m.is_empty() || !self.needs_crate_flavor(flavor) {
563 } else if m.len() == 1 {
564 return Ok(Some(m.into_iter().next().unwrap()));
568 let mut ret: Option<(PathBuf, PathKind)> = None;
569 let mut err_data: Option<Vec<PathBuf>> = None;
570 for (lib, kind) in m {
571 info!("{} reading metadata from: {}", flavor, lib.display());
572 if flavor == CrateFlavor::Rmeta && lib.metadata().map_or(false, |m| m.len() == 0) {
573 // Empty files will cause get_metadata_section to fail. Rmeta
574 // files can be empty, for example with binaries (which can
575 // often appear with `cargo check` when checking a library as
576 // a unittest). We don't want to emit a user-visible warning
577 // in this case as it is not a real problem.
578 debug!("skipping empty file");
581 let (hash, metadata) =
582 match get_metadata_section(self.target, flavor, &lib, self.metadata_loader) {
584 if let Some(h) = self.crate_matches(&blob, &lib) {
587 info!("metadata mismatch");
591 Err(MetadataError::LoadFailure(err)) => {
592 info!("no metadata found: {}", err);
593 // The file was present and created by the same compiler version, but we
594 // couldn't load it for some reason. Give a hard error instead of silently
595 // ignoring it, but only if we would have given an error anyway.
596 self.crate_rejections
598 .push(CrateMismatch { path: lib, got: err });
601 Err(err @ MetadataError::NotPresent(_)) => {
602 info!("no metadata found: {}", err);
606 // If we see multiple hashes, emit an error about duplicate candidates.
607 if slot.as_ref().map_or(false, |s| s.0 != hash) {
608 if let Some(candidates) = err_data {
609 return Err(CrateError::MultipleCandidates(
615 err_data = Some(vec![ret.as_ref().unwrap().0.clone()]);
618 if let Some(candidates) = &mut err_data {
619 candidates.push(lib);
623 // Ok so at this point we've determined that `(lib, kind)` above is
624 // a candidate crate to load, and that `slot` is either none (this
625 // is the first crate of its kind) or if some the previous path has
626 // the exact same hash (e.g., it's the exact same crate).
628 // In principle these two candidate crates are exactly the same so
629 // we can choose either of them to link. As a stupidly gross hack,
630 // however, we favor crate in the sysroot.
632 // You can find more info in rust-lang/rust#39518 and various linked
633 // issues, but the general gist is that during testing libstd the
634 // compilers has two candidates to choose from: one in the sysroot
635 // and one in the deps folder. These two crates are the exact same
636 // crate but if the compiler chooses the one in the deps folder
637 // it'll cause spurious errors on Windows.
639 // As a result, we favor the sysroot crate here. Note that the
640 // candidates are all canonicalized, so we canonicalize the sysroot
642 if let Some((prev, _)) = &ret {
643 let sysroot = self.sysroot;
644 let sysroot = sysroot.canonicalize().unwrap_or_else(|_| sysroot.to_path_buf());
645 if prev.starts_with(&sysroot) {
649 *slot = Some((hash, metadata));
650 ret = Some((lib, kind));
653 if let Some(candidates) = err_data {
654 Err(CrateError::MultipleCandidates(self.crate_name, flavor, candidates))
660 fn crate_matches(&mut self, metadata: &MetadataBlob, libpath: &Path) -> Option<Svh> {
661 let rustc_version = rustc_version();
662 let found_version = metadata.get_rustc_version();
663 if found_version != rustc_version {
664 info!("Rejecting via version: expected {} got {}", rustc_version, found_version);
665 self.crate_rejections
667 .push(CrateMismatch { path: libpath.to_path_buf(), got: found_version });
671 let root = metadata.get_root();
672 if root.is_proc_macro_crate() != self.is_proc_macro {
674 "Rejecting via proc macro: expected {} got {}",
676 root.is_proc_macro_crate(),
681 if self.exact_paths.is_empty() && self.crate_name != root.name() {
682 info!("Rejecting via crate name");
686 if root.triple() != &self.triple {
687 info!("Rejecting via crate triple: expected {} got {}", self.triple, root.triple());
688 self.crate_rejections.via_triple.push(CrateMismatch {
689 path: libpath.to_path_buf(),
690 got: root.triple().to_string(),
695 let hash = root.hash();
696 if let Some(expected_hash) = self.hash {
697 if hash != expected_hash {
698 info!("Rejecting via hash: expected {} got {}", expected_hash, hash);
699 self.crate_rejections
701 .push(CrateMismatch { path: libpath.to_path_buf(), got: hash.to_string() });
709 fn find_commandline_library(&mut self) -> Result<Option<Library>, CrateError> {
710 // First, filter out all libraries that look suspicious. We only accept
711 // files which actually exist that have the correct naming scheme for
713 let mut rlibs = FxHashMap::default();
714 let mut rmetas = FxHashMap::default();
715 let mut dylibs = FxHashMap::default();
716 for loc in &self.exact_paths {
717 if !loc.canonicalized().exists() {
718 return Err(CrateError::ExternLocationNotExist(
720 loc.original().clone(),
723 if !loc.original().is_file() {
724 return Err(CrateError::ExternLocationNotFile(
726 loc.original().clone(),
729 let Some(file) = loc.original().file_name().and_then(|s| s.to_str()) else {
730 return Err(CrateError::ExternLocationNotFile(
732 loc.original().clone(),
736 if file.starts_with("lib") && (file.ends_with(".rlib") || file.ends_with(".rmeta"))
737 || file.starts_with(self.target.dll_prefix.as_ref())
738 && file.ends_with(self.target.dll_suffix.as_ref())
740 // Make sure there's at most one rlib and at most one dylib.
741 // Note to take care and match against the non-canonicalized name:
742 // some systems save build artifacts into content-addressed stores
743 // that do not preserve extensions, and then link to them using
744 // e.g. symbolic links. If we canonicalize too early, we resolve
745 // the symlink, the file type is lost and we might treat rlibs and
747 let loc_canon = loc.canonicalized().clone();
748 let loc = loc.original();
749 if loc.file_name().unwrap().to_str().unwrap().ends_with(".rlib") {
750 rlibs.insert(loc_canon, PathKind::ExternFlag);
751 } else if loc.file_name().unwrap().to_str().unwrap().ends_with(".rmeta") {
752 rmetas.insert(loc_canon, PathKind::ExternFlag);
754 dylibs.insert(loc_canon, PathKind::ExternFlag);
757 self.crate_rejections
759 .push(CrateMismatch { path: loc.original().clone(), got: String::new() });
763 // Extract the dylib/rlib/rmeta triple.
764 Ok(self.extract_lib(rlibs, rmetas, dylibs)?.map(|(_, lib)| lib))
767 pub(crate) fn into_error(self, root: Option<CratePaths>) -> CrateError {
768 CrateError::LocatorCombined(CombinedLocatorError {
769 crate_name: self.crate_name,
772 dll_prefix: self.target.dll_prefix.to_string(),
773 dll_suffix: self.target.dll_suffix.to_string(),
774 crate_rejections: self.crate_rejections,
779 fn get_metadata_section<'p>(
783 loader: &dyn MetadataLoader,
784 ) -> Result<MetadataBlob, MetadataError<'p>> {
785 if !filename.exists() {
786 return Err(MetadataError::NotPresent(filename));
788 let raw_bytes: MetadataRef = match flavor {
789 CrateFlavor::Rlib => {
790 loader.get_rlib_metadata(target, filename).map_err(MetadataError::LoadFailure)?
792 CrateFlavor::Dylib => {
794 loader.get_dylib_metadata(target, filename).map_err(MetadataError::LoadFailure)?;
795 // The header is uncompressed
796 let header_len = METADATA_HEADER.len();
797 debug!("checking {} bytes of metadata-version stamp", header_len);
798 let header = &buf[..cmp::min(header_len, buf.len())];
799 if header != METADATA_HEADER {
800 return Err(MetadataError::LoadFailure(format!(
801 "invalid metadata version found: {}",
806 // Header is okay -> inflate the actual metadata
807 let compressed_bytes = &buf[header_len..];
808 debug!("inflating {} bytes of compressed metadata", compressed_bytes.len());
809 // Assume the decompressed data will be at least the size of the compressed data, so we
810 // don't have to grow the buffer as much.
811 let mut inflated = Vec::with_capacity(compressed_bytes.len());
812 match FrameDecoder::new(compressed_bytes).read_to_end(&mut inflated) {
813 Ok(_) => rustc_erase_owner!(OwningRef::new(inflated).map_owner_box()),
815 return Err(MetadataError::LoadFailure(format!(
816 "failed to decompress metadata: {}",
822 CrateFlavor::Rmeta => {
823 // mmap the file, because only a small fraction of it is read.
824 let file = std::fs::File::open(filename).map_err(|_| {
825 MetadataError::LoadFailure(format!(
826 "failed to open rmeta metadata: '{}'",
830 let mmap = unsafe { Mmap::map(file) };
831 let mmap = mmap.map_err(|_| {
832 MetadataError::LoadFailure(format!(
833 "failed to mmap rmeta metadata: '{}'",
838 rustc_erase_owner!(OwningRef::new(mmap).map_owner_box())
841 let blob = MetadataBlob::new(raw_bytes);
842 if blob.is_compatible() {
845 Err(MetadataError::LoadFailure(format!(
846 "invalid metadata version found: {}",
852 /// Look for a plugin registrar. Returns its library path and crate disambiguator.
853 pub fn find_plugin_registrar(
855 metadata_loader: &dyn MetadataLoader,
859 find_plugin_registrar_impl(sess, metadata_loader, name).unwrap_or_else(|err| {
860 // `core` is always available if we got as far as loading plugins.
861 err.report(sess, span, false);
866 fn find_plugin_registrar_impl<'a>(
868 metadata_loader: &dyn MetadataLoader,
870 ) -> Result<PathBuf, CrateError> {
871 info!("find plugin registrar `{}`", name);
872 let mut locator = CrateLocator::new(
877 None, // extra_filename
882 match locator.maybe_load_library_crate()? {
883 Some(library) => match library.source.dylib {
884 Some(dylib) => Ok(dylib.0),
885 None => Err(CrateError::NonDylibPlugin(name)),
887 None => Err(locator.into_error(None)),
891 /// A diagnostic function for dumping crate metadata to an output stream.
892 pub fn list_file_metadata(
895 metadata_loader: &dyn MetadataLoader,
898 let flavor = get_flavor_from_path(path);
899 match get_metadata_section(target, flavor, path, metadata_loader) {
900 Ok(metadata) => metadata.list_crate_metadata(out),
901 Err(msg) => write!(out, "{}\n", msg),
905 fn get_flavor_from_path(path: &Path) -> CrateFlavor {
906 let filename = path.file_name().unwrap().to_str().unwrap();
908 if filename.ends_with(".rlib") {
910 } else if filename.ends_with(".rmeta") {
917 // ------------------------------------------ Error reporting -------------------------------------
920 struct CrateMismatch {
925 #[derive(Clone, Default)]
926 struct CrateRejections {
927 via_hash: Vec<CrateMismatch>,
928 via_triple: Vec<CrateMismatch>,
929 via_kind: Vec<CrateMismatch>,
930 via_version: Vec<CrateMismatch>,
931 via_filename: Vec<CrateMismatch>,
932 via_invalid: Vec<CrateMismatch>,
935 /// Candidate rejection reasons collected during crate search.
936 /// If no candidate is accepted, then these reasons are presented to the user,
937 /// otherwise they are ignored.
938 pub(crate) struct CombinedLocatorError {
940 root: Option<CratePaths>,
941 triple: TargetTriple,
944 crate_rejections: CrateRejections,
947 pub(crate) enum CrateError {
948 NonAsciiName(Symbol),
949 ExternLocationNotExist(Symbol, PathBuf),
950 ExternLocationNotFile(Symbol, PathBuf),
951 MultipleCandidates(Symbol, CrateFlavor, Vec<PathBuf>),
952 SymbolConflictsCurrent(Symbol),
953 SymbolConflictsOthers(Symbol),
954 StableCrateIdCollision(Symbol, Symbol),
957 LocatorCombined(CombinedLocatorError),
958 NonDylibPlugin(Symbol),
961 enum MetadataError<'a> {
962 /// The file was missing.
963 NotPresent(&'a Path),
964 /// The file was present and invalid.
968 impl fmt::Display for MetadataError<'_> {
969 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
971 MetadataError::NotPresent(filename) => {
972 f.write_str(&format!("no such file: '{}'", filename.display()))
974 MetadataError::LoadFailure(msg) => f.write_str(msg),
980 pub(crate) fn report(self, sess: &Session, span: Span, missing_core: bool) {
982 CrateError::NonAsciiName(crate_name) => {
983 sess.emit_err(NonAsciiName { span, crate_name });
985 CrateError::ExternLocationNotExist(crate_name, loc) => {
986 sess.emit_err(ExternLocationNotExist { span, crate_name, location: &loc });
988 CrateError::ExternLocationNotFile(crate_name, loc) => {
989 sess.emit_err(ExternLocationNotFile { span, crate_name, location: &loc });
991 CrateError::MultipleCandidates(crate_name, flavor, candidates) => {
992 sess.emit_err(MultipleCandidates { span, crate_name, flavor, candidates });
994 CrateError::SymbolConflictsCurrent(root_name) => {
995 sess.emit_err(SymbolConflictsCurrent { span, crate_name: root_name });
997 CrateError::SymbolConflictsOthers(root_name) => {
998 sess.emit_err(SymbolConflictsOthers { span, crate_name: root_name });
1000 CrateError::StableCrateIdCollision(crate_name0, crate_name1) => {
1001 sess.emit_err(StableCrateIdCollision { span, crate_name0, crate_name1 });
1003 CrateError::DlOpen(s) | CrateError::DlSym(s) => {
1004 sess.emit_err(DlError { span, err: s });
1006 CrateError::LocatorCombined(locator) => {
1007 let crate_name = locator.crate_name;
1008 let add_info = match &locator.root {
1009 None => String::new(),
1010 Some(r) => format!(" which `{}` depends on", r.name),
1012 if !locator.crate_rejections.via_filename.is_empty() {
1013 let mismatches = locator.crate_rejections.via_filename.iter();
1014 for CrateMismatch { path, .. } in mismatches {
1015 sess.emit_err(CrateLocationUnknownType { span, path: &path, crate_name });
1016 sess.emit_err(LibFilenameForm {
1018 dll_prefix: &locator.dll_prefix,
1019 dll_suffix: &locator.dll_suffix,
1023 let mut found_crates = String::new();
1024 if !locator.crate_rejections.via_hash.is_empty() {
1025 let mismatches = locator.crate_rejections.via_hash.iter();
1026 for CrateMismatch { path, .. } in mismatches {
1027 found_crates.push_str(&format!(
1033 if let Some(r) = locator.root {
1034 for path in r.source.paths() {
1035 found_crates.push_str(&format!(
1042 sess.emit_err(NewerCrateVersion {
1044 crate_name: crate_name,
1048 } else if !locator.crate_rejections.via_triple.is_empty() {
1049 let mismatches = locator.crate_rejections.via_triple.iter();
1050 for CrateMismatch { path, got } in mismatches {
1051 found_crates.push_str(&format!(
1052 "\ncrate `{}`, target triple {}: {}",
1058 sess.emit_err(NoCrateWithTriple {
1061 locator_triple: locator.triple.triple(),
1065 } else if !locator.crate_rejections.via_kind.is_empty() {
1066 let mismatches = locator.crate_rejections.via_kind.iter();
1067 for CrateMismatch { path, .. } in mismatches {
1068 found_crates.push_str(&format!(
1074 sess.emit_err(FoundStaticlib { span, crate_name, add_info, found_crates });
1075 } else if !locator.crate_rejections.via_version.is_empty() {
1076 let mismatches = locator.crate_rejections.via_version.iter();
1077 for CrateMismatch { path, got } in mismatches {
1078 found_crates.push_str(&format!(
1079 "\ncrate `{}` compiled by {}: {}",
1085 sess.emit_err(IncompatibleRustc {
1090 rustc_version: rustc_version(),
1092 } else if !locator.crate_rejections.via_invalid.is_empty() {
1093 let mut crate_rejections = Vec::new();
1094 for CrateMismatch { path: _, got } in locator.crate_rejections.via_invalid {
1095 crate_rejections.push(got);
1097 sess.emit_err(InvalidMetadataFiles {
1104 sess.emit_err(CannotFindCrate {
1113 .unwrap_or("<unknown>".to_string()),
1114 is_nightly_build: sess.is_nightly_build(),
1115 profiler_runtime: Symbol::intern(&sess.opts.unstable_opts.profiler_runtime),
1116 locator_triple: locator.triple,
1120 CrateError::NonDylibPlugin(crate_name) => {
1121 sess.emit_err(NoDylibPlugin { span, crate_name });