1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Finds crate binaries and loads their metadata
13 //! Might I be the first to welcome you to a world of platform differences,
14 //! version requirements, dependency graphs, conflicting desires, and fun! This
15 //! is the major guts (along with metadata::creader) of the compiler for loading
16 //! crates and resolving dependencies. Let's take a tour!
20 //! Each invocation of the compiler is immediately concerned with one primary
21 //! problem, to connect a set of crates to resolved crates on the filesystem.
22 //! Concretely speaking, the compiler follows roughly these steps to get here:
24 //! 1. Discover a set of `extern crate` statements.
25 //! 2. Transform these directives into crate names. If the directive does not
26 //! have an explicit name, then the identifier is the name.
27 //! 3. For each of these crate names, find a corresponding crate on the
30 //! Sounds easy, right? Let's walk into some of the nuances.
32 //! ## Transitive Dependencies
34 //! Let's say we've got three crates: A, B, and C. A depends on B, and B depends
35 //! on C. When we're compiling A, we primarily need to find and locate B, but we
36 //! also end up needing to find and locate C as well.
38 //! The reason for this is that any of B's types could be composed of C's types,
39 //! any function in B could return a type from C, etc. To be able to guarantee
40 //! that we can always typecheck/translate any function, we have to have
41 //! complete knowledge of the whole ecosystem, not just our immediate
44 //! So now as part of the "find a corresponding crate on the filesystem" step
45 //! above, this involves also finding all crates for *all upstream
46 //! dependencies*. This includes all dependencies transitively.
48 //! ## Rlibs and Dylibs
50 //! The compiler has two forms of intermediate dependencies. These are dubbed
51 //! rlibs and dylibs for the static and dynamic variants, respectively. An rlib
52 //! is a rustc-defined file format (currently just an ar archive) while a dylib
53 //! is a platform-defined dynamic library. Each library has a metadata somewhere
56 //! A third kind of dependency is an rmeta file. These are metadata files and do
57 //! not contain any code, etc. To a first approximation, these are treated in the
58 //! same way as rlibs. Where there is both an rlib and an rmeta file, the rlib
59 //! gets priority (even if the rmeta file is newer). An rmeta file is only
60 //! useful for checking a downstream crate, attempting to link one will cause an
63 //! When translating a crate name to a crate on the filesystem, we all of a
64 //! sudden need to take into account both rlibs and dylibs! Linkage later on may
65 //! use either one of these files, as each has their pros/cons. The job of crate
66 //! loading is to discover what's possible by finding all candidates.
68 //! Most parts of this loading systems keep the dylib/rlib as just separate
73 //! We can't exactly scan your whole hard drive when looking for dependencies,
74 //! so we need to places to look. Currently the compiler will implicitly add the
75 //! target lib search path ($prefix/lib/rustlib/$target/lib) to any compilation,
76 //! and otherwise all -L flags are added to the search paths.
78 //! ## What criterion to select on?
80 //! This a pretty tricky area of loading crates. Given a file, how do we know
81 //! whether it's the right crate? Currently, the rules look along these lines:
83 //! 1. Does the filename match an rlib/dylib pattern? That is to say, does the
84 //! filename have the right prefix/suffix?
85 //! 2. Does the filename have the right prefix for the crate name being queried?
86 //! This is filtering for files like `libfoo*.rlib` and such. If the crate
87 //! we're looking for was originally compiled with -C extra-filename, the
88 //! extra filename will be included in this prefix to reduce reading
89 //! metadata from crates that would otherwise share our prefix.
90 //! 3. Is the file an actual rust library? This is done by loading the metadata
91 //! from the library and making sure it's actually there.
92 //! 4. Does the name in the metadata agree with the name of the library?
93 //! 5. Does the target in the metadata agree with the current target?
94 //! 6. Does the SVH match? (more on this later)
96 //! If the file answers `yes` to all these questions, then the file is
97 //! considered as being *candidate* for being accepted. It is illegal to have
98 //! more than two candidates as the compiler has no method by which to resolve
99 //! this conflict. Additionally, rlib/dylib candidates are considered
102 //! After all this has happened, we have 1 or two files as candidates. These
103 //! represent the rlib/dylib file found for a library, and they're returned as
106 //! ### What about versions?
108 //! A lot of effort has been put forth to remove versioning from the compiler.
109 //! There have been forays in the past to have versioning baked in, but it was
110 //! largely always deemed insufficient to the point that it was recognized that
111 //! it's probably something the compiler shouldn't do anyway due to its
112 //! complicated nature and the state of the half-baked solutions.
114 //! With a departure from versioning, the primary criterion for loading crates
115 //! is just the name of a crate. If we stopped here, it would imply that you
116 //! could never link two crates of the same name from different sources
117 //! together, which is clearly a bad state to be in.
119 //! To resolve this problem, we come to the next section!
123 //! A number of flags have been added to the compiler to solve the "version
124 //! problem" in the previous section, as well as generally enabling more
125 //! powerful usage of the crate loading system of the compiler. The goal of
126 //! these flags and options are to enable third-party tools to drive the
127 //! compiler with prior knowledge about how the world should look.
129 //! ## The `--extern` flag
131 //! The compiler accepts a flag of this form a number of times:
134 //! --extern crate-name=path/to/the/crate.rlib
137 //! This flag is basically the following letter to the compiler:
141 //! > When you are attempting to load the immediate dependency `crate-name`, I
142 //! > would like you to assume that the library is located at
143 //! > `path/to/the/crate.rlib`, and look nowhere else. Also, please do not
144 //! > assume that the path I specified has the name `crate-name`.
146 //! This flag basically overrides most matching logic except for validating that
147 //! the file is indeed a rust library. The same `crate-name` can be specified
148 //! twice to specify the rlib/dylib pair.
150 //! ## Enabling "multiple versions"
152 //! This basically boils down to the ability to specify arbitrary packages to
153 //! the compiler. For example, if crate A wanted to use Bv1 and Bv2, then it
154 //! would look something like:
156 //! ```compile_fail,E0463
163 //! and the compiler would be invoked as:
166 //! rustc a.rs --extern b1=path/to/libb1.rlib --extern b2=path/to/libb2.rlib
169 //! In this scenario there are two crates named `b` and the compiler must be
170 //! manually driven to be informed where each crate is.
172 //! ## Frobbing symbols
174 //! One of the immediate problems with linking the same library together twice
175 //! in the same problem is dealing with duplicate symbols. The primary way to
176 //! deal with this in rustc is to add hashes to the end of each symbol.
178 //! In order to force hashes to change between versions of a library, if
179 //! desired, the compiler exposes an option `-C metadata=foo`, which is used to
180 //! initially seed each symbol hash. The string `foo` is prepended to each
181 //! string-to-hash to ensure that symbols change over time.
183 //! ## Loading transitive dependencies
185 //! Dealing with same-named-but-distinct crates is not just a local problem, but
186 //! one that also needs to be dealt with for transitive dependencies. Note that
187 //! in the letter above `--extern` flags only apply to the *local* set of
188 //! dependencies, not the upstream transitive dependencies. Consider this
189 //! dependency graph:
201 //! In this scenario, when we compile `D`, we need to be able to distinctly
202 //! resolve `A.1` and `A.2`, but an `--extern` flag cannot apply to these
203 //! transitive dependencies.
205 //! Note that the key idea here is that `B` and `C` are both *already compiled*.
206 //! That is, they have already resolved their dependencies. Due to unrelated
207 //! technical reasons, when a library is compiled, it is only compatible with
208 //! the *exact same* version of the upstream libraries it was compiled against.
209 //! We use the "Strict Version Hash" to identify the exact copy of an upstream
212 //! With this knowledge, we know that `B` and `C` will depend on `A` with
213 //! different SVH values, so we crawl the normal `-L` paths looking for
214 //! `liba*.rlib` and filter based on the contained SVH.
216 //! In the end, this ends up not needing `--extern` to specify upstream
217 //! transitive dependencies.
221 //! That's the general overview of loading crates in the compiler, but it's by
222 //! no means all of the necessary details. Take a look at the rest of
223 //! metadata::locator or metadata::creader for all the juicy details!
225 use cstore::{MetadataRef, MetadataBlob};
226 use creader::Library;
227 use schema::{METADATA_HEADER, rustc_version};
229 use rustc_data_structures::fx::FxHashSet;
230 use rustc_data_structures::svh::Svh;
231 use rustc::middle::cstore::MetadataLoader;
232 use rustc::session::{config, Session};
233 use rustc::session::filesearch::{FileSearch, FileMatches, FileDoesntMatch};
234 use rustc::session::search_paths::PathKind;
235 use rustc::util::nodemap::FxHashMap;
237 use errors::DiagnosticBuilder;
238 use syntax::symbol::Symbol;
239 use syntax_pos::Span;
240 use rustc_target::spec::{Target, TargetTriple};
245 use std::io::{self, Read};
246 use std::path::{Path, PathBuf};
247 use std::time::Instant;
249 use flate2::read::DeflateDecoder;
251 use rustc_data_structures::owning_ref::OwningRef;
252 pub struct CrateMismatch {
257 pub struct Context<'a> {
258 pub sess: &'a Session,
261 pub crate_name: Symbol,
262 pub hash: Option<&'a Svh>,
263 pub extra_filename: Option<&'a str>,
264 // points to either self.sess.target.target or self.sess.host, must match triple
265 pub target: &'a Target,
266 pub triple: &'a TargetTriple,
267 pub filesearch: FileSearch<'a>,
268 pub root: &'a Option<CratePaths>,
269 pub rejected_via_hash: Vec<CrateMismatch>,
270 pub rejected_via_triple: Vec<CrateMismatch>,
271 pub rejected_via_kind: Vec<CrateMismatch>,
272 pub rejected_via_version: Vec<CrateMismatch>,
273 pub rejected_via_filename: Vec<CrateMismatch>,
274 pub should_match_name: bool,
275 pub is_proc_macro: Option<bool>,
276 pub metadata_loader: &'a dyn MetadataLoader,
279 pub struct CratePaths {
281 pub dylib: Option<PathBuf>,
282 pub rlib: Option<PathBuf>,
283 pub rmeta: Option<PathBuf>,
286 #[derive(Copy, Clone, PartialEq)]
293 impl fmt::Display for CrateFlavor {
294 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
295 f.write_str(match *self {
296 CrateFlavor::Rlib => "rlib",
297 CrateFlavor::Rmeta => "rmeta",
298 CrateFlavor::Dylib => "dylib",
304 fn paths(&self) -> Vec<PathBuf> {
305 self.dylib.iter().chain(self.rlib.iter()).chain(self.rmeta.iter()).cloned().collect()
309 impl<'a> Context<'a> {
310 pub fn maybe_load_library_crate(&mut self) -> Option<Library> {
311 let mut seen_paths = FxHashSet::default();
312 match self.extra_filename {
313 Some(s) => self.find_library_crate(s, &mut seen_paths)
314 .or_else(|| self.find_library_crate("", &mut seen_paths)),
315 None => self.find_library_crate("", &mut seen_paths)
319 pub fn report_errs(&mut self) -> ! {
320 let add = match self.root {
321 &None => String::new(),
322 &Some(ref r) => format!(" which `{}` depends on", r.ident),
324 let mut msg = "the following crate versions were found:".to_string();
325 let mut err = if !self.rejected_via_hash.is_empty() {
326 let mut err = struct_span_err!(self.sess,
329 "found possibly newer version of crate `{}`{}",
332 err.note("perhaps that crate needs to be recompiled?");
333 let mismatches = self.rejected_via_hash.iter();
334 for &CrateMismatch { ref path, .. } in mismatches {
335 msg.push_str(&format!("\ncrate `{}`: {}", self.ident, path.display()));
340 for path in r.paths().iter() {
341 msg.push_str(&format!("\ncrate `{}`: {}", r.ident, path.display()));
347 } else if !self.rejected_via_triple.is_empty() {
348 let mut err = struct_span_err!(self.sess,
351 "couldn't find crate `{}` \
352 with expected target triple {}{}",
356 let mismatches = self.rejected_via_triple.iter();
357 for &CrateMismatch { ref path, ref got } in mismatches {
358 msg.push_str(&format!("\ncrate `{}`, target triple {}: {}",
365 } else if !self.rejected_via_kind.is_empty() {
366 let mut err = struct_span_err!(self.sess,
369 "found staticlib `{}` instead of rlib or dylib{}",
372 err.help("please recompile that crate using --crate-type lib");
373 let mismatches = self.rejected_via_kind.iter();
374 for &CrateMismatch { ref path, .. } in mismatches {
375 msg.push_str(&format!("\ncrate `{}`: {}", self.ident, path.display()));
379 } else if !self.rejected_via_version.is_empty() {
380 let mut err = struct_span_err!(self.sess,
383 "found crate `{}` compiled by an incompatible version \
387 err.help(&format!("please recompile that crate using this compiler ({})",
389 let mismatches = self.rejected_via_version.iter();
390 for &CrateMismatch { ref path, ref got } in mismatches {
391 msg.push_str(&format!("\ncrate `{}` compiled by {}: {}",
399 let mut err = struct_span_err!(self.sess,
402 "can't find crate for `{}`{}",
406 if (self.ident == "std" || self.ident == "core")
407 && self.triple != &TargetTriple::from_triple(config::host_triple()) {
408 err.note(&format!("the `{}` target may not be installed", self.triple));
410 err.span_label(self.span, "can't find crate");
414 if !self.rejected_via_filename.is_empty() {
415 let dylibname = self.dylibname();
416 let mismatches = self.rejected_via_filename.iter();
417 for &CrateMismatch { ref path, .. } in mismatches {
418 err.note(&format!("extern location for {} is of an unknown type: {}",
421 .help(&format!("file name should be lib*.rlib or {}*.{}",
428 self.sess.abort_if_errors();
432 fn find_library_crate(&mut self,
434 seen_paths: &mut FxHashSet<PathBuf>)
436 // If an SVH is specified, then this is a transitive dependency that
437 // must be loaded via -L plus some filtering.
438 if self.hash.is_none() {
439 self.should_match_name = false;
440 if let Some(s) = self.sess.opts.externs.get(&self.crate_name.as_str()) {
441 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
442 if s.iter().any(|l| l.is_some()) {
443 return self.find_commandline_library(
444 s.iter().filter_map(|l| l.as_ref()),
448 self.should_match_name = true;
451 let dypair = self.dylibname();
452 let staticpair = self.staticlibname();
454 // want: crate_name.dir_part() + prefix + crate_name.file_part + "-"
455 let dylib_prefix = format!("{}{}{}", dypair.0, self.crate_name, extra_prefix);
456 let rlib_prefix = format!("lib{}{}", self.crate_name, extra_prefix);
457 let staticlib_prefix = format!("{}{}{}", staticpair.0, self.crate_name, extra_prefix);
459 let mut candidates: FxHashMap<
461 (FxHashMap<_, _>, FxHashMap<_, _>, FxHashMap<_, _>),
462 > = Default::default();
463 let mut staticlibs = vec![];
465 // First, find all possible candidate rlibs and dylibs purely based on
466 // the name of the files themselves. We're trying to match against an
467 // exact crate name and a possibly an exact hash.
469 // During this step, we can filter all found libraries based on the
470 // name and id found in the crate id (we ignore the path portion for
471 // filename matching), as well as the exact hash (if specified). If we
472 // end up having many candidates, we must look at the metadata to
473 // perform exact matches against hashes/crate ids. Note that opening up
474 // the metadata is where we do an exact match against the full contents
475 // of the crate id (path/name/id).
477 // The goal of this step is to look at as little metadata as possible.
478 self.filesearch.search(|path, kind| {
479 let file = match path.file_name().and_then(|s| s.to_str()) {
480 None => return FileDoesntMatch,
483 let (hash, found_kind) =
484 if file.starts_with(&rlib_prefix) && file.ends_with(".rlib") {
485 (&file[(rlib_prefix.len())..(file.len() - ".rlib".len())], CrateFlavor::Rlib)
486 } else if file.starts_with(&rlib_prefix) && file.ends_with(".rmeta") {
487 (&file[(rlib_prefix.len())..(file.len() - ".rmeta".len())], CrateFlavor::Rmeta)
488 } else if file.starts_with(&dylib_prefix) &&
489 file.ends_with(&dypair.1) {
490 (&file[(dylib_prefix.len())..(file.len() - dypair.1.len())], CrateFlavor::Dylib)
492 if file.starts_with(&staticlib_prefix) && file.ends_with(&staticpair.1) {
493 staticlibs.push(CrateMismatch {
494 path: path.to_path_buf(),
495 got: "static".to_string(),
498 return FileDoesntMatch;
501 info!("lib candidate: {}", path.display());
503 let hash_str = hash.to_string();
504 let slot = candidates.entry(hash_str).or_default();
505 let (ref mut rlibs, ref mut rmetas, ref mut dylibs) = *slot;
506 fs::canonicalize(path)
508 if seen_paths.contains(&p) {
509 return FileDoesntMatch
511 seen_paths.insert(p.clone());
513 CrateFlavor::Rlib => { rlibs.insert(p, kind); }
514 CrateFlavor::Rmeta => { rmetas.insert(p, kind); }
515 CrateFlavor::Dylib => { dylibs.insert(p, kind); }
519 .unwrap_or(FileDoesntMatch)
521 self.rejected_via_kind.extend(staticlibs);
523 // We have now collected all known libraries into a set of candidates
524 // keyed of the filename hash listed. For each filename, we also have a
525 // list of rlibs/dylibs that apply. Here, we map each of these lists
526 // (per hash), to a Library candidate for returning.
528 // A Library candidate is created if the metadata for the set of
529 // libraries corresponds to the crate id and hash criteria that this
530 // search is being performed for.
531 let mut libraries = FxHashMap::default();
532 for (_hash, (rlibs, rmetas, dylibs)) in candidates {
534 let rlib = self.extract_one(rlibs, CrateFlavor::Rlib, &mut slot);
535 let rmeta = self.extract_one(rmetas, CrateFlavor::Rmeta, &mut slot);
536 let dylib = self.extract_one(dylibs, CrateFlavor::Dylib, &mut slot);
537 if let Some((h, m)) = slot {
548 // Having now translated all relevant found hashes into libraries, see
549 // what we've got and figure out if we found multiple candidates for
551 match libraries.len() {
553 1 => Some(libraries.into_iter().next().unwrap().1),
555 let mut err = struct_span_err!(self.sess,
558 "multiple matching crates for `{}`",
560 let candidates = libraries.iter().filter_map(|(_, lib)| {
561 let crate_name = &lib.metadata.get_root().name.as_str();
562 match &(&lib.dylib, &lib.rlib) {
563 &(&Some((ref pd, _)), &Some((ref pr, _))) => {
564 Some(format!("\ncrate `{}`: {}\n{:>padding$}",
568 padding=8 + crate_name.len()))
570 &(&Some((ref p, _)), &None) | &(&None, &Some((ref p, _))) => {
571 Some(format!("\ncrate `{}`: {}", crate_name, p.display()))
573 &(&None, &None) => None,
575 }).collect::<String>();
576 err.note(&format!("candidates:{}", candidates));
583 // Attempts to extract *one* library from the set `m`. If the set has no
584 // elements, `None` is returned. If the set has more than one element, then
585 // the errors and notes are emitted about the set of libraries.
587 // With only one library in the set, this function will extract it, and then
588 // read the metadata from it if `*slot` is `None`. If the metadata couldn't
589 // be read, it is assumed that the file isn't a valid rust library (no
590 // errors are emitted).
591 fn extract_one(&mut self,
592 m: FxHashMap<PathBuf, PathKind>,
594 slot: &mut Option<(Svh, MetadataBlob)>)
595 -> Option<(PathBuf, PathKind)> {
596 let mut ret: Option<(PathBuf, PathKind)> = None;
600 // FIXME(#10786): for an optimization, we only read one of the
601 // libraries' metadata sections. In theory we should
602 // read both, but reading dylib metadata is quite
606 } else if m.len() == 1 {
607 return Some(m.into_iter().next().unwrap());
611 let mut err: Option<DiagnosticBuilder> = None;
612 for (lib, kind) in m {
613 info!("{} reading metadata from: {}", flavor, lib.display());
614 let (hash, metadata) =
615 match get_metadata_section(self.target, flavor, &lib, self.metadata_loader) {
617 if let Some(h) = self.crate_matches(&blob, &lib) {
620 info!("metadata mismatch");
625 warn!("no metadata found: {}", err);
629 // If we see multiple hashes, emit an error about duplicate candidates.
630 if slot.as_ref().map_or(false, |s| s.0 != hash) {
631 let mut e = struct_span_err!(self.sess,
634 "multiple {} candidates for `{}` found",
637 e.span_note(self.span,
638 &format!(r"candidate #1: {}",
643 if let Some(ref mut e) = err {
652 err.as_mut().unwrap().span_note(self.span,
653 &format!(r"candidate #{}: {}",
659 // Ok so at this point we've determined that `(lib, kind)` above is
660 // a candidate crate to load, and that `slot` is either none (this
661 // is the first crate of its kind) or if some the previous path has
662 // the exact same hash (e.g. it's the exact same crate).
664 // In principle these two candidate crates are exactly the same so
665 // we can choose either of them to link. As a stupidly gross hack,
666 // however, we favor crate in the sysroot.
668 // You can find more info in rust-lang/rust#39518 and various linked
669 // issues, but the general gist is that during testing libstd the
670 // compilers has two candidates to choose from: one in the sysroot
671 // and one in the deps folder. These two crates are the exact same
672 // crate but if the compiler chooses the one in the deps folder
673 // it'll cause spurious errors on Windows.
675 // As a result, we favor the sysroot crate here. Note that the
676 // candidates are all canonicalized, so we canonicalize the sysroot
678 if let Some((ref prev, _)) = ret {
679 let sysroot = self.sess.sysroot();
680 let sysroot = sysroot.canonicalize()
681 .unwrap_or_else(|_| sysroot.to_path_buf());
682 if prev.starts_with(&sysroot) {
686 *slot = Some((hash, metadata));
687 ret = Some((lib, kind));
698 fn crate_matches(&mut self, metadata: &MetadataBlob, libpath: &Path) -> Option<Svh> {
699 let rustc_version = rustc_version();
700 let found_version = metadata.get_rustc_version();
701 if found_version != rustc_version {
702 info!("Rejecting via version: expected {} got {}",
705 self.rejected_via_version.push(CrateMismatch {
706 path: libpath.to_path_buf(),
712 let root = metadata.get_root();
713 if let Some(is_proc_macro) = self.is_proc_macro {
714 if root.macro_derive_registrar.is_some() != is_proc_macro {
719 if self.should_match_name {
720 if self.crate_name != root.name {
721 info!("Rejecting via crate name");
726 if &root.triple != self.triple {
727 info!("Rejecting via crate triple: expected {} got {}",
730 self.rejected_via_triple.push(CrateMismatch {
731 path: libpath.to_path_buf(),
732 got: root.triple.to_string(),
737 if let Some(myhash) = self.hash {
738 if *myhash != root.hash {
739 info!("Rejecting via hash: expected {} got {}", *myhash, root.hash);
740 self.rejected_via_hash.push(CrateMismatch {
741 path: libpath.to_path_buf(),
742 got: myhash.to_string(),
752 // Returns the corresponding (prefix, suffix) that files need to have for
754 fn dylibname(&self) -> (String, String) {
755 let t = &self.target;
756 (t.options.dll_prefix.clone(), t.options.dll_suffix.clone())
759 // Returns the corresponding (prefix, suffix) that files need to have for
761 fn staticlibname(&self) -> (String, String) {
762 let t = &self.target;
763 (t.options.staticlib_prefix.clone(), t.options.staticlib_suffix.clone())
766 fn find_commandline_library<'b, LOCS>(&mut self, locs: LOCS) -> Option<Library>
767 where LOCS: Iterator<Item = &'b String>
769 // First, filter out all libraries that look suspicious. We only accept
770 // files which actually exist that have the correct naming scheme for
772 let sess = self.sess;
773 let dylibname = self.dylibname();
774 let mut rlibs = FxHashMap::default();
775 let mut rmetas = FxHashMap::default();
776 let mut dylibs = FxHashMap::default();
778 let locs = locs.map(|l| PathBuf::from(l)).filter(|loc| {
780 sess.err(&format!("extern location for {} does not exist: {}",
785 let file = match loc.file_name().and_then(|s| s.to_str()) {
788 sess.err(&format!("extern location for {} is not a file: {}",
794 if file.starts_with("lib") &&
795 (file.ends_with(".rlib") || file.ends_with(".rmeta")) {
798 let (ref prefix, ref suffix) = dylibname;
799 if file.starts_with(&prefix[..]) && file.ends_with(&suffix[..]) {
804 self.rejected_via_filename.push(CrateMismatch {
812 // Now that we have an iterator of good candidates, make sure
813 // there's at most one rlib and at most one dylib.
815 if loc.file_name().unwrap().to_str().unwrap().ends_with(".rlib") {
816 rlibs.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
817 } else if loc.file_name().unwrap().to_str().unwrap().ends_with(".rmeta") {
818 rmetas.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
820 dylibs.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
825 // Extract the rlib/dylib pair.
827 let rlib = self.extract_one(rlibs, CrateFlavor::Rlib, &mut slot);
828 let rmeta = self.extract_one(rmetas, CrateFlavor::Rmeta, &mut slot);
829 let dylib = self.extract_one(dylibs, CrateFlavor::Dylib, &mut slot);
831 if rlib.is_none() && rmeta.is_none() && dylib.is_none() {
834 slot.map(|(_, metadata)|
845 // Just a small wrapper to time how long reading metadata takes.
846 fn get_metadata_section(target: &Target,
849 loader: &dyn MetadataLoader)
850 -> Result<MetadataBlob, String> {
851 let start = Instant::now();
852 let ret = get_metadata_section_imp(target, flavor, filename, loader);
853 info!("reading {:?} => {:?}",
854 filename.file_name().unwrap(),
859 fn get_metadata_section_imp(target: &Target,
862 loader: &dyn MetadataLoader)
863 -> Result<MetadataBlob, String> {
864 if !filename.exists() {
865 return Err(format!("no such file: '{}'", filename.display()));
867 let raw_bytes: MetadataRef = match flavor {
868 CrateFlavor::Rlib => loader.get_rlib_metadata(target, filename)?,
869 CrateFlavor::Dylib => {
870 let buf = loader.get_dylib_metadata(target, filename)?;
871 // The header is uncompressed
872 let header_len = METADATA_HEADER.len();
873 debug!("checking {} bytes of metadata-version stamp", header_len);
874 let header = &buf[..cmp::min(header_len, buf.len())];
875 if header != METADATA_HEADER {
876 return Err(format!("incompatible metadata version found: '{}'",
877 filename.display()));
880 // Header is okay -> inflate the actual metadata
881 let compressed_bytes = &buf[header_len..];
882 debug!("inflating {} bytes of compressed metadata", compressed_bytes.len());
883 let mut inflated = Vec::new();
884 match DeflateDecoder::new(compressed_bytes).read_to_end(&mut inflated) {
886 let buf = unsafe { OwningRef::new_assert_stable_address(inflated) };
887 rustc_erase_owner!(buf.map_owner_box())
890 return Err(format!("failed to decompress metadata: {}", filename.display()));
894 CrateFlavor::Rmeta => {
895 let buf = fs::read(filename).map_err(|_|
896 format!("failed to read rmeta metadata: '{}'", filename.display()))?;
897 rustc_erase_owner!(OwningRef::new(buf).map_owner_box())
900 let blob = MetadataBlob(raw_bytes);
901 if blob.is_compatible() {
904 Err(format!("incompatible metadata version found: '{}'", filename.display()))
908 // A diagnostic function for dumping crate metadata to an output stream
909 pub fn list_file_metadata(target: &Target,
911 loader: &dyn MetadataLoader,
912 out: &mut dyn io::Write)
914 let filename = path.file_name().unwrap().to_str().unwrap();
915 let flavor = if filename.ends_with(".rlib") {
917 } else if filename.ends_with(".rmeta") {
922 match get_metadata_section(target, flavor, path, loader) {
923 Ok(metadata) => metadata.list_crate_metadata(out),
924 Err(msg) => write!(out, "{}\n", msg),