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 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;
216 use crate::rmeta::{METADATA_HEADER, rustc_version, MetadataBlob};
218 use rustc_data_structures::fx::FxHashSet;
219 use rustc_data_structures::svh::Svh;
220 use rustc_data_structures::sync::MetadataRef;
221 use rustc::middle::cstore::{CrateSource, MetadataLoader};
222 use rustc::session::{config, Session, CrateDisambiguator};
223 use rustc::session::filesearch::{FileSearch, FileMatches, FileDoesntMatch};
224 use rustc::session::search_paths::PathKind;
225 use rustc::util::nodemap::FxHashMap;
227 use errors::DiagnosticBuilder;
228 use syntax::{span_err, span_fatal};
229 use syntax::symbol::{Symbol, sym};
230 use syntax::struct_span_err;
231 use syntax_pos::Span;
232 use rustc_target::spec::{Target, TargetTriple};
237 use std::io::{self, Read};
239 use std::path::{Path, PathBuf};
240 use std::time::Instant;
242 use flate2::read::DeflateDecoder;
244 use rustc_data_structures::owning_ref::OwningRef;
246 use log::{debug, info, warn};
248 use rustc_error_codes::*;
251 struct CrateMismatch {
257 crate struct CrateLocator<'a> {
258 // Immutable per-session configuration.
260 metadata_loader: &'a dyn MetadataLoader,
262 // Immutable per-search configuration.
264 pub hash: Option<&'a Svh>,
265 pub host_hash: Option<&'a Svh>,
266 extra_filename: Option<&'a str>,
267 pub target: &'a Target,
268 pub triple: TargetTriple,
269 pub filesearch: FileSearch<'a>,
271 root: Option<&'a CratePaths>,
272 pub is_proc_macro: Option<bool>,
274 // Mutable in-progress state or output.
275 rejected_via_hash: Vec<CrateMismatch>,
276 rejected_via_triple: Vec<CrateMismatch>,
277 rejected_via_kind: Vec<CrateMismatch>,
278 rejected_via_version: Vec<CrateMismatch>,
279 rejected_via_filename: Vec<CrateMismatch>,
280 should_match_name: bool,
283 crate struct CratePaths {
289 crate fn new(name: Symbol, source: CrateSource) -> CratePaths {
290 CratePaths { name, source }
294 #[derive(Copy, Clone, PartialEq)]
301 impl fmt::Display for CrateFlavor {
302 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
303 f.write_str(match *self {
304 CrateFlavor::Rlib => "rlib",
305 CrateFlavor::Rmeta => "rmeta",
306 CrateFlavor::Dylib => "dylib",
311 impl<'a> CrateLocator<'a> {
314 metadata_loader: &'a dyn MetadataLoader,
316 hash: Option<&'a Svh>,
317 host_hash: Option<&'a Svh>,
318 extra_filename: Option<&'a str>,
322 root: Option<&'a CratePaths>,
323 is_proc_macro: Option<bool>,
324 ) -> CrateLocator<'a> {
332 target: if is_host { &sess.host } else { &sess.target.target },
334 TargetTriple::from_triple(config::host_triple())
336 sess.opts.target_triple.clone()
338 filesearch: if is_host {
339 sess.host_filesearch(path_kind)
341 sess.target_filesearch(path_kind)
346 rejected_via_hash: Vec::new(),
347 rejected_via_triple: Vec::new(),
348 rejected_via_kind: Vec::new(),
349 rejected_via_version: Vec::new(),
350 rejected_via_filename: Vec::new(),
351 should_match_name: true,
355 crate fn reset(&mut self) {
356 self.rejected_via_hash.clear();
357 self.rejected_via_triple.clear();
358 self.rejected_via_kind.clear();
359 self.rejected_via_version.clear();
360 self.rejected_via_filename.clear();
363 crate fn maybe_load_library_crate(&mut self) -> Option<Library> {
364 let mut seen_paths = FxHashSet::default();
365 match self.extra_filename {
366 Some(s) => self.find_library_crate(s, &mut seen_paths)
367 .or_else(|| self.find_library_crate("", &mut seen_paths)),
368 None => self.find_library_crate("", &mut seen_paths)
372 crate fn report_errs(self) -> ! {
373 let add = match self.root {
374 None => String::new(),
375 Some(r) => format!(" which `{}` depends on", r.name),
377 let mut msg = "the following crate versions were found:".to_string();
378 let mut err = if !self.rejected_via_hash.is_empty() {
379 let mut err = struct_span_err!(self.sess,
382 "found possibly newer version of crate `{}`{}",
385 err.note("perhaps that crate needs to be recompiled?");
386 let mismatches = self.rejected_via_hash.iter();
387 for &CrateMismatch { ref path, .. } in mismatches {
388 msg.push_str(&format!("\ncrate `{}`: {}", self.crate_name, path.display()));
393 for path in r.source.paths() {
394 msg.push_str(&format!("\ncrate `{}`: {}", r.name, path.display()));
400 } else if !self.rejected_via_triple.is_empty() {
401 let mut err = struct_span_err!(self.sess,
404 "couldn't find crate `{}` \
405 with expected target triple {}{}",
409 let mismatches = self.rejected_via_triple.iter();
410 for &CrateMismatch { ref path, ref got } in mismatches {
411 msg.push_str(&format!("\ncrate `{}`, target triple {}: {}",
418 } else if !self.rejected_via_kind.is_empty() {
419 let mut err = struct_span_err!(self.sess,
422 "found staticlib `{}` instead of rlib or dylib{}",
425 err.help("please recompile that crate using --crate-type lib");
426 let mismatches = self.rejected_via_kind.iter();
427 for &CrateMismatch { ref path, .. } in mismatches {
428 msg.push_str(&format!("\ncrate `{}`: {}", self.crate_name, path.display()));
432 } else if !self.rejected_via_version.is_empty() {
433 let mut err = struct_span_err!(self.sess,
436 "found crate `{}` compiled by an incompatible version \
440 err.help(&format!("please recompile that crate using this compiler ({})",
442 let mismatches = self.rejected_via_version.iter();
443 for &CrateMismatch { ref path, ref got } in mismatches {
444 msg.push_str(&format!("\ncrate `{}` compiled by {}: {}",
452 let mut err = struct_span_err!(self.sess,
455 "can't find crate for `{}`{}",
459 if (self.crate_name == sym::std || self.crate_name == sym::core)
460 && self.triple != TargetTriple::from_triple(config::host_triple()) {
461 err.note(&format!("the `{}` target may not be installed", self.triple));
463 err.span_label(self.span, "can't find crate");
467 if !self.rejected_via_filename.is_empty() {
468 let dylibname = self.dylibname();
469 let mismatches = self.rejected_via_filename.iter();
470 for &CrateMismatch { ref path, .. } in mismatches {
471 err.note(&format!("extern location for {} is of an unknown type: {}",
474 .help(&format!("file name should be lib*.rlib or {}*.{}",
481 self.sess.abort_if_errors();
485 fn find_library_crate(&mut self,
487 seen_paths: &mut FxHashSet<PathBuf>)
489 // If an SVH is specified, then this is a transitive dependency that
490 // must be loaded via -L plus some filtering.
491 if self.hash.is_none() {
492 self.should_match_name = false;
493 if let Some(entry) = self.sess.opts.externs.get(&self.crate_name.as_str()) {
494 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
495 if entry.locations.iter().any(|l| l.is_some()) {
496 return self.find_commandline_library(
497 entry.locations.iter().filter_map(|l| l.as_ref()),
501 self.should_match_name = true;
504 let dypair = self.dylibname();
505 let staticpair = self.staticlibname();
507 // want: crate_name.dir_part() + prefix + crate_name.file_part + "-"
508 let dylib_prefix = format!("{}{}{}", dypair.0, self.crate_name, extra_prefix);
509 let rlib_prefix = format!("lib{}{}", self.crate_name, extra_prefix);
510 let staticlib_prefix = format!("{}{}{}", staticpair.0, self.crate_name, extra_prefix);
512 let mut candidates: FxHashMap<
514 (FxHashMap<_, _>, FxHashMap<_, _>, FxHashMap<_, _>),
515 > = Default::default();
516 let mut staticlibs = vec![];
518 // First, find all possible candidate rlibs and dylibs purely based on
519 // the name of the files themselves. We're trying to match against an
520 // exact crate name and a possibly an exact hash.
522 // During this step, we can filter all found libraries based on the
523 // name and id found in the crate id (we ignore the path portion for
524 // filename matching), as well as the exact hash (if specified). If we
525 // end up having many candidates, we must look at the metadata to
526 // perform exact matches against hashes/crate ids. Note that opening up
527 // the metadata is where we do an exact match against the full contents
528 // of the crate id (path/name/id).
530 // The goal of this step is to look at as little metadata as possible.
531 self.filesearch.search(|path, kind| {
532 let file = match path.file_name().and_then(|s| s.to_str()) {
533 None => return FileDoesntMatch,
536 let (hash, found_kind) =
537 if file.starts_with(&rlib_prefix) && file.ends_with(".rlib") {
538 (&file[(rlib_prefix.len())..(file.len() - ".rlib".len())], CrateFlavor::Rlib)
539 } else if file.starts_with(&rlib_prefix) && file.ends_with(".rmeta") {
540 (&file[(rlib_prefix.len())..(file.len() - ".rmeta".len())], CrateFlavor::Rmeta)
541 } else if file.starts_with(&dylib_prefix) &&
542 file.ends_with(&dypair.1) {
543 (&file[(dylib_prefix.len())..(file.len() - dypair.1.len())], CrateFlavor::Dylib)
545 if file.starts_with(&staticlib_prefix) && file.ends_with(&staticpair.1) {
546 staticlibs.push(CrateMismatch {
547 path: path.to_path_buf(),
548 got: "static".to_string(),
551 return FileDoesntMatch;
554 info!("lib candidate: {}", path.display());
556 let hash_str = hash.to_string();
557 let slot = candidates.entry(hash_str).or_default();
558 let (ref mut rlibs, ref mut rmetas, ref mut dylibs) = *slot;
559 fs::canonicalize(path)
561 if seen_paths.contains(&p) {
562 return FileDoesntMatch
564 seen_paths.insert(p.clone());
566 CrateFlavor::Rlib => { rlibs.insert(p, kind); }
567 CrateFlavor::Rmeta => { rmetas.insert(p, kind); }
568 CrateFlavor::Dylib => { dylibs.insert(p, kind); }
572 .unwrap_or(FileDoesntMatch)
574 self.rejected_via_kind.extend(staticlibs);
576 // We have now collected all known libraries into a set of candidates
577 // keyed of the filename hash listed. For each filename, we also have a
578 // list of rlibs/dylibs that apply. Here, we map each of these lists
579 // (per hash), to a Library candidate for returning.
581 // A Library candidate is created if the metadata for the set of
582 // libraries corresponds to the crate id and hash criteria that this
583 // search is being performed for.
584 let mut libraries = FxHashMap::default();
585 for (_hash, (rlibs, rmetas, dylibs)) in candidates {
586 if let Some((svh, lib)) = self.extract_lib(rlibs, rmetas, dylibs) {
587 libraries.insert(svh, lib);
591 // Having now translated all relevant found hashes into libraries, see
592 // what we've got and figure out if we found multiple candidates for
594 match libraries.len() {
596 1 => Some(libraries.into_iter().next().unwrap().1),
598 let mut err = struct_span_err!(self.sess,
601 "multiple matching crates for `{}`",
603 let candidates = libraries.iter().filter_map(|(_, lib)| {
604 let crate_name = &lib.metadata.get_root().name.as_str();
605 match &(&lib.source.dylib, &lib.source.rlib) {
606 &(&Some((ref pd, _)), &Some((ref pr, _))) => {
607 Some(format!("\ncrate `{}`: {}\n{:>padding$}",
611 padding=8 + crate_name.len()))
613 &(&Some((ref p, _)), &None) | &(&None, &Some((ref p, _))) => {
614 Some(format!("\ncrate `{}`: {}", crate_name, p.display()))
616 &(&None, &None) => None,
618 }).collect::<String>();
619 err.note(&format!("candidates:{}", candidates));
628 rlibs: FxHashMap<PathBuf, PathKind>,
629 rmetas: FxHashMap<PathBuf, PathKind>,
630 dylibs: FxHashMap<PathBuf, PathKind>,
631 ) -> Option<(Svh, Library)> {
633 let source = CrateSource {
634 rlib: self.extract_one(rlibs, CrateFlavor::Rlib, &mut slot),
635 rmeta: self.extract_one(rmetas, CrateFlavor::Rmeta, &mut slot),
636 dylib: self.extract_one(dylibs, CrateFlavor::Dylib, &mut slot),
638 slot.map(|(svh, metadata)| (svh, Library { source, metadata }))
641 // Attempts to extract *one* library from the set `m`. If the set has no
642 // elements, `None` is returned. If the set has more than one element, then
643 // the errors and notes are emitted about the set of libraries.
645 // With only one library in the set, this function will extract it, and then
646 // read the metadata from it if `*slot` is `None`. If the metadata couldn't
647 // be read, it is assumed that the file isn't a valid rust library (no
648 // errors are emitted).
649 fn extract_one(&mut self,
650 m: FxHashMap<PathBuf, PathKind>,
652 slot: &mut Option<(Svh, MetadataBlob)>)
653 -> Option<(PathBuf, PathKind)> {
654 let mut ret: Option<(PathBuf, PathKind)> = None;
658 // FIXME(#10786): for an optimization, we only read one of the
659 // libraries' metadata sections. In theory we should
660 // read both, but reading dylib metadata is quite
664 } else if m.len() == 1 {
665 return Some(m.into_iter().next().unwrap());
669 let mut err: Option<DiagnosticBuilder<'_>> = None;
670 for (lib, kind) in m {
671 info!("{} reading metadata from: {}", flavor, lib.display());
672 let (hash, metadata) =
673 match get_metadata_section(self.target, flavor, &lib, self.metadata_loader) {
675 if let Some(h) = self.crate_matches(&blob, &lib) {
678 info!("metadata mismatch");
683 warn!("no metadata found: {}", err);
687 // If we see multiple hashes, emit an error about duplicate candidates.
688 if slot.as_ref().map_or(false, |s| s.0 != hash) {
689 let mut e = struct_span_err!(self.sess,
692 "multiple {} candidates for `{}` found",
695 e.span_note(self.span,
696 &format!(r"candidate #1: {}",
701 if let Some(ref mut e) = err {
710 err.as_mut().unwrap().span_note(self.span,
711 &format!(r"candidate #{}: {}",
717 // Ok so at this point we've determined that `(lib, kind)` above is
718 // a candidate crate to load, and that `slot` is either none (this
719 // is the first crate of its kind) or if some the previous path has
720 // the exact same hash (e.g., it's the exact same crate).
722 // In principle these two candidate crates are exactly the same so
723 // we can choose either of them to link. As a stupidly gross hack,
724 // however, we favor crate in the sysroot.
726 // You can find more info in rust-lang/rust#39518 and various linked
727 // issues, but the general gist is that during testing libstd the
728 // compilers has two candidates to choose from: one in the sysroot
729 // and one in the deps folder. These two crates are the exact same
730 // crate but if the compiler chooses the one in the deps folder
731 // it'll cause spurious errors on Windows.
733 // As a result, we favor the sysroot crate here. Note that the
734 // candidates are all canonicalized, so we canonicalize the sysroot
736 if let Some((ref prev, _)) = ret {
737 let sysroot = &self.sess.sysroot;
738 let sysroot = sysroot.canonicalize()
739 .unwrap_or_else(|_| sysroot.to_path_buf());
740 if prev.starts_with(&sysroot) {
744 *slot = Some((hash, metadata));
745 ret = Some((lib, kind));
756 fn crate_matches(&mut self, metadata: &MetadataBlob, libpath: &Path) -> Option<Svh> {
757 let rustc_version = rustc_version();
758 let found_version = metadata.get_rustc_version();
759 if found_version != rustc_version {
760 info!("Rejecting via version: expected {} got {}",
763 self.rejected_via_version.push(CrateMismatch {
764 path: libpath.to_path_buf(),
770 let root = metadata.get_root();
771 if let Some(is_proc_macro) = self.is_proc_macro {
772 if root.proc_macro_data.is_some() != is_proc_macro {
773 info!("Rejecting via proc macro: expected {} got {}",
774 is_proc_macro, root.proc_macro_data.is_some());
779 if self.should_match_name {
780 if self.crate_name != root.name {
781 info!("Rejecting via crate name");
786 if root.triple != self.triple {
787 info!("Rejecting via crate triple: expected {} got {}",
790 self.rejected_via_triple.push(CrateMismatch {
791 path: libpath.to_path_buf(),
792 got: root.triple.to_string(),
797 if let Some(myhash) = self.hash {
798 if *myhash != root.hash {
799 info!("Rejecting via hash: expected {} got {}", *myhash, root.hash);
800 self.rejected_via_hash.push(CrateMismatch {
801 path: libpath.to_path_buf(),
802 got: myhash.to_string(),
812 // Returns the corresponding (prefix, suffix) that files need to have for
814 fn dylibname(&self) -> (String, String) {
815 let t = &self.target;
816 (t.options.dll_prefix.clone(), t.options.dll_suffix.clone())
819 // Returns the corresponding (prefix, suffix) that files need to have for
821 fn staticlibname(&self) -> (String, String) {
822 let t = &self.target;
823 (t.options.staticlib_prefix.clone(), t.options.staticlib_suffix.clone())
826 fn find_commandline_library<'b, LOCS>(&mut self, locs: LOCS) -> Option<Library>
827 where LOCS: Iterator<Item = &'b String>
829 // First, filter out all libraries that look suspicious. We only accept
830 // files which actually exist that have the correct naming scheme for
832 let sess = self.sess;
833 let dylibname = self.dylibname();
834 let mut rlibs = FxHashMap::default();
835 let mut rmetas = FxHashMap::default();
836 let mut dylibs = FxHashMap::default();
838 let locs = locs.map(|l| PathBuf::from(l)).filter(|loc| {
840 sess.err(&format!("extern location for {} does not exist: {}",
845 let file = match loc.file_name().and_then(|s| s.to_str()) {
848 sess.err(&format!("extern location for {} is not a file: {}",
854 if file.starts_with("lib") &&
855 (file.ends_with(".rlib") || file.ends_with(".rmeta")) {
858 let (ref prefix, ref suffix) = dylibname;
859 if file.starts_with(&prefix[..]) && file.ends_with(&suffix[..]) {
864 self.rejected_via_filename.push(CrateMismatch {
872 // Now that we have an iterator of good candidates, make sure
873 // there's at most one rlib and at most one dylib.
875 if loc.file_name().unwrap().to_str().unwrap().ends_with(".rlib") {
876 rlibs.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
877 } else if loc.file_name().unwrap().to_str().unwrap().ends_with(".rmeta") {
878 rmetas.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
880 dylibs.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
885 // Extract the dylib/rlib/rmeta triple.
886 self.extract_lib(rlibs, rmetas, dylibs).map(|(_, lib)| lib)
890 // Just a small wrapper to time how long reading metadata takes.
891 fn get_metadata_section(target: &Target,
894 loader: &dyn MetadataLoader)
895 -> Result<MetadataBlob, String> {
896 let start = Instant::now();
897 let ret = get_metadata_section_imp(target, flavor, filename, loader);
898 info!("reading {:?} => {:?}",
899 filename.file_name().unwrap(),
904 /// A trivial wrapper for `Mmap` that implements `StableDeref`.
905 struct StableDerefMmap(memmap::Mmap);
907 impl Deref for StableDerefMmap {
910 fn deref(&self) -> &[u8] {
915 unsafe impl stable_deref_trait::StableDeref for StableDerefMmap {}
917 fn get_metadata_section_imp(target: &Target,
920 loader: &dyn MetadataLoader)
921 -> Result<MetadataBlob, String> {
922 if !filename.exists() {
923 return Err(format!("no such file: '{}'", filename.display()));
925 let raw_bytes: MetadataRef = match flavor {
926 CrateFlavor::Rlib => loader.get_rlib_metadata(target, filename)?,
927 CrateFlavor::Dylib => {
928 let buf = loader.get_dylib_metadata(target, filename)?;
929 // The header is uncompressed
930 let header_len = METADATA_HEADER.len();
931 debug!("checking {} bytes of metadata-version stamp", header_len);
932 let header = &buf[..cmp::min(header_len, buf.len())];
933 if header != METADATA_HEADER {
934 return Err(format!("incompatible metadata version found: '{}'",
935 filename.display()));
938 // Header is okay -> inflate the actual metadata
939 let compressed_bytes = &buf[header_len..];
940 debug!("inflating {} bytes of compressed metadata", compressed_bytes.len());
941 let mut inflated = Vec::new();
942 match DeflateDecoder::new(compressed_bytes).read_to_end(&mut inflated) {
944 rustc_erase_owner!(OwningRef::new(inflated).map_owner_box())
947 return Err(format!("failed to decompress metadata: {}", filename.display()));
951 CrateFlavor::Rmeta => {
952 // mmap the file, because only a small fraction of it is read.
953 let file = std::fs::File::open(filename).map_err(|_|
954 format!("failed to open rmeta metadata: '{}'", filename.display()))?;
955 let mmap = unsafe { memmap::Mmap::map(&file) };
956 let mmap = mmap.map_err(|_|
957 format!("failed to mmap rmeta metadata: '{}'", filename.display()))?;
959 rustc_erase_owner!(OwningRef::new(StableDerefMmap(mmap)).map_owner_box())
962 let blob = MetadataBlob::new(raw_bytes);
963 if blob.is_compatible() {
966 Err(format!("incompatible metadata version found: '{}'", filename.display()))
970 /// Look for a plugin registrar. Returns its library path and crate disambiguator.
971 pub fn find_plugin_registrar(
973 metadata_loader: &dyn MetadataLoader,
976 ) -> Option<(PathBuf, CrateDisambiguator)> {
977 info!("find plugin registrar `{}`", name);
978 let target_triple = sess.opts.target_triple.clone();
979 let host_triple = TargetTriple::from_triple(config::host_triple());
980 let is_cross = target_triple != host_triple;
981 let mut target_only = false;
982 let mut locator = CrateLocator::new(
988 None, // extra_filename
993 None, // is_proc_macro
996 let library = locator.maybe_load_library_crate().or_else(|| {
1000 // Try loading from target crates. This will abort later if we
1001 // try to load a plugin registrar function,
1004 locator.target = &sess.target.target;
1005 locator.triple = target_triple;
1006 locator.filesearch = sess.target_filesearch(PathKind::Crate);
1008 locator.maybe_load_library_crate()
1010 let library = match library {
1012 None => locator.report_errs(),
1016 // Need to abort before syntax expansion.
1017 let message = format!("plugin `{}` is not available for triple `{}` \
1020 config::host_triple(),
1021 sess.opts.target_triple);
1022 span_fatal!(sess, span, E0456, "{}", &message);
1025 match library.source.dylib {
1027 Some((dylib.0, library.metadata.get_root().disambiguator))
1030 span_err!(sess, span, E0457,
1031 "plugin `{}` only found in rlib format, but must be available \
1034 // No need to abort because the loading code will just ignore this
1041 /// A diagnostic function for dumping crate metadata to an output stream.
1042 pub fn list_file_metadata(target: &Target,
1044 metadata_loader: &dyn MetadataLoader,
1045 out: &mut dyn io::Write)
1047 let filename = path.file_name().unwrap().to_str().unwrap();
1048 let flavor = if filename.ends_with(".rlib") {
1050 } else if filename.ends_with(".rmeta") {
1055 match get_metadata_section(target, flavor, path, metadata_loader) {
1056 Ok(metadata) => metadata.list_crate_metadata(out),
1057 Err(msg) => write!(out, "{}\n", msg),