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.
87 //! 3. Is the file an actual rust library? This is done by loading the metadata
88 //! from the library and making sure it's actually there.
89 //! 4. Does the name in the metadata agree with the name of the library?
90 //! 5. Does the target in the metadata agree with the current target?
91 //! 6. Does the SVH match? (more on this later)
93 //! If the file answers `yes` to all these questions, then the file is
94 //! considered as being *candidate* for being accepted. It is illegal to have
95 //! more than two candidates as the compiler has no method by which to resolve
96 //! this conflict. Additionally, rlib/dylib candidates are considered
99 //! After all this has happened, we have 1 or two files as candidates. These
100 //! represent the rlib/dylib file found for a library, and they're returned as
103 //! ### What about versions?
105 //! A lot of effort has been put forth to remove versioning from the compiler.
106 //! There have been forays in the past to have versioning baked in, but it was
107 //! largely always deemed insufficient to the point that it was recognized that
108 //! it's probably something the compiler shouldn't do anyway due to its
109 //! complicated nature and the state of the half-baked solutions.
111 //! With a departure from versioning, the primary criterion for loading crates
112 //! is just the name of a crate. If we stopped here, it would imply that you
113 //! could never link two crates of the same name from different sources
114 //! together, which is clearly a bad state to be in.
116 //! To resolve this problem, we come to the next section!
120 //! A number of flags have been added to the compiler to solve the "version
121 //! problem" in the previous section, as well as generally enabling more
122 //! powerful usage of the crate loading system of the compiler. The goal of
123 //! these flags and options are to enable third-party tools to drive the
124 //! compiler with prior knowledge about how the world should look.
126 //! ## The `--extern` flag
128 //! The compiler accepts a flag of this form a number of times:
131 //! --extern crate-name=path/to/the/crate.rlib
134 //! This flag is basically the following letter to the compiler:
138 //! > When you are attempting to load the immediate dependency `crate-name`, I
139 //! > would like you to assume that the library is located at
140 //! > `path/to/the/crate.rlib`, and look nowhere else. Also, please do not
141 //! > assume that the path I specified has the name `crate-name`.
143 //! This flag basically overrides most matching logic except for validating that
144 //! the file is indeed a rust library. The same `crate-name` can be specified
145 //! twice to specify the rlib/dylib pair.
147 //! ## Enabling "multiple versions"
149 //! This basically boils down to the ability to specify arbitrary packages to
150 //! the compiler. For example, if crate A wanted to use Bv1 and Bv2, then it
151 //! would look something like:
160 //! and the compiler would be invoked as:
163 //! rustc a.rs --extern b1=path/to/libb1.rlib --extern b2=path/to/libb2.rlib
166 //! In this scenario there are two crates named `b` and the compiler must be
167 //! manually driven to be informed where each crate is.
169 //! ## Frobbing symbols
171 //! One of the immediate problems with linking the same library together twice
172 //! in the same problem is dealing with duplicate symbols. The primary way to
173 //! deal with this in rustc is to add hashes to the end of each symbol.
175 //! In order to force hashes to change between versions of a library, if
176 //! desired, the compiler exposes an option `-C metadata=foo`, which is used to
177 //! initially seed each symbol hash. The string `foo` is prepended to each
178 //! string-to-hash to ensure that symbols change over time.
180 //! ## Loading transitive dependencies
182 //! Dealing with same-named-but-distinct crates is not just a local problem, but
183 //! one that also needs to be dealt with for transitive dependencies. Note that
184 //! in the letter above `--extern` flags only apply to the *local* set of
185 //! dependencies, not the upstream transitive dependencies. Consider this
186 //! dependency graph:
198 //! In this scenario, when we compile `D`, we need to be able to distinctly
199 //! resolve `A.1` and `A.2`, but an `--extern` flag cannot apply to these
200 //! transitive dependencies.
202 //! Note that the key idea here is that `B` and `C` are both *already compiled*.
203 //! That is, they have already resolved their dependencies. Due to unrelated
204 //! technical reasons, when a library is compiled, it is only compatible with
205 //! the *exact same* version of the upstream libraries it was compiled against.
206 //! We use the "Strict Version Hash" to identify the exact copy of an upstream
209 //! With this knowledge, we know that `B` and `C` will depend on `A` with
210 //! different SVH values, so we crawl the normal `-L` paths looking for
211 //! `liba*.rlib` and filter based on the contained SVH.
213 //! In the end, this ends up not needing `--extern` to specify upstream
214 //! transitive dependencies.
218 //! That's the general overview of loading crates in the compiler, but it's by
219 //! no means all of the necessary details. Take a look at the rest of
220 //! metadata::locator or metadata::creader for all the juicy details!
222 use cstore::MetadataBlob;
223 use creader::Library;
224 use schema::{METADATA_HEADER, rustc_version};
226 use rustc::hir::svh::Svh;
227 use rustc::session::{config, Session};
228 use rustc::session::filesearch::{FileSearch, FileMatches, FileDoesntMatch};
229 use rustc::session::search_paths::PathKind;
230 use rustc::util::common;
231 use rustc::util::nodemap::FxHashMap;
233 use rustc_llvm as llvm;
234 use rustc_llvm::{False, ObjectFile, mk_section_iter};
235 use rustc_llvm::archive_ro::ArchiveRO;
236 use errors::DiagnosticBuilder;
237 use syntax::symbol::Symbol;
238 use syntax_pos::Span;
239 use rustc_back::target::Target;
243 use std::fs::{self, File};
244 use std::io::{self, Read};
245 use std::path::{Path, PathBuf};
248 use std::time::Instant;
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 // points to either self.sess.target.target or self.sess.host, must match triple
264 pub target: &'a Target,
266 pub filesearch: FileSearch<'a>,
267 pub root: &'a Option<CratePaths>,
268 pub rejected_via_hash: Vec<CrateMismatch>,
269 pub rejected_via_triple: Vec<CrateMismatch>,
270 pub rejected_via_kind: Vec<CrateMismatch>,
271 pub rejected_via_version: Vec<CrateMismatch>,
272 pub rejected_via_filename: Vec<CrateMismatch>,
273 pub should_match_name: bool,
274 pub is_proc_macro: Option<bool>,
277 pub struct ArchiveMetadata {
279 // points into self._archive
283 pub struct CratePaths {
285 pub dylib: Option<PathBuf>,
286 pub rlib: Option<PathBuf>,
287 pub rmeta: Option<PathBuf>,
290 pub const METADATA_FILENAME: &'static str = "rust.metadata.bin";
292 #[derive(Copy, Clone, PartialEq)]
299 impl fmt::Display for CrateFlavor {
300 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
301 f.write_str(match *self {
302 CrateFlavor::Rlib => "rlib",
303 CrateFlavor::Rmeta => "rmeta",
304 CrateFlavor::Dylib => "dylib",
310 fn paths(&self) -> Vec<PathBuf> {
311 self.dylib.iter().chain(self.rlib.iter()).chain(self.rmeta.iter()).cloned().collect()
315 impl<'a> Context<'a> {
316 pub fn maybe_load_library_crate(&mut self) -> Option<Library> {
317 self.find_library_crate()
320 pub fn load_library_crate(&mut self) -> Library {
321 self.find_library_crate().unwrap_or_else(|| self.report_errs())
324 pub fn report_errs(&mut self) -> ! {
325 let add = match self.root {
326 &None => String::new(),
327 &Some(ref r) => format!(" which `{}` depends on", r.ident),
329 let mut err = if !self.rejected_via_hash.is_empty() {
330 struct_span_err!(self.sess,
333 "found possibly newer version of crate `{}`{}",
336 } else if !self.rejected_via_triple.is_empty() {
337 struct_span_err!(self.sess,
340 "couldn't find crate `{}` with expected target triple {}{}",
344 } else if !self.rejected_via_kind.is_empty() {
345 struct_span_err!(self.sess,
348 "found staticlib `{}` instead of rlib or dylib{}",
351 } else if !self.rejected_via_version.is_empty() {
352 struct_span_err!(self.sess,
355 "found crate `{}` compiled by an incompatible version of rustc{}",
359 let mut err = struct_span_err!(self.sess,
362 "can't find crate for `{}`{}",
366 if (self.ident == "std" || self.ident == "core")
367 && self.triple != config::host_triple() {
368 err.note(&format!("the `{}` target may not be installed", self.triple));
370 err.span_label(self.span, &format!("can't find crate"));
374 if !self.rejected_via_triple.is_empty() {
375 let mismatches = self.rejected_via_triple.iter();
376 for (i, &CrateMismatch { ref path, ref got }) in mismatches.enumerate() {
377 err.note(&format!("crate `{}`, path #{}, triple {}: {}",
384 if !self.rejected_via_hash.is_empty() {
385 err.note("perhaps that crate needs to be recompiled?");
386 let mismatches = self.rejected_via_hash.iter();
387 for (i, &CrateMismatch { ref path, .. }) in mismatches.enumerate() {
388 err.note(&format!("crate `{}` path #{}: {}", self.ident, i + 1, path.display()));
393 for (i, path) in r.paths().iter().enumerate() {
394 err.note(&format!("crate `{}` path #{}: {}",
402 if !self.rejected_via_kind.is_empty() {
403 err.help("please recompile that crate using --crate-type lib");
404 let mismatches = self.rejected_via_kind.iter();
405 for (i, &CrateMismatch { ref path, .. }) in mismatches.enumerate() {
406 err.note(&format!("crate `{}` path #{}: {}", self.ident, i + 1, path.display()));
409 if !self.rejected_via_version.is_empty() {
410 err.help(&format!("please recompile that crate using this compiler ({})",
412 let mismatches = self.rejected_via_version.iter();
413 for (i, &CrateMismatch { ref path, ref got }) in mismatches.enumerate() {
414 err.note(&format!("crate `{}` path #{}: {} compiled by {:?}",
421 if !self.rejected_via_filename.is_empty() {
422 let dylibname = self.dylibname();
423 let mismatches = self.rejected_via_filename.iter();
424 for &CrateMismatch { ref path, .. } in mismatches {
425 err.note(&format!("extern location for {} is of an unknown type: {}",
428 .help(&format!("file name should be lib*.rlib or {}*.{}",
435 self.sess.abort_if_errors();
439 fn find_library_crate(&mut self) -> Option<Library> {
440 // If an SVH is specified, then this is a transitive dependency that
441 // must be loaded via -L plus some filtering.
442 if self.hash.is_none() {
443 self.should_match_name = false;
444 if let Some(s) = self.sess.opts.externs.get(&self.crate_name.as_str()) {
445 return self.find_commandline_library(s.iter());
447 self.should_match_name = true;
450 let dypair = self.dylibname();
451 let staticpair = self.staticlibname();
453 // want: crate_name.dir_part() + prefix + crate_name.file_part + "-"
454 let dylib_prefix = format!("{}{}", dypair.0, self.crate_name);
455 let rlib_prefix = format!("lib{}", self.crate_name);
456 let staticlib_prefix = format!("{}{}", staticpair.0, self.crate_name);
458 let mut candidates = FxHashMap();
459 let mut staticlibs = vec![];
461 // First, find all possible candidate rlibs and dylibs purely based on
462 // the name of the files themselves. We're trying to match against an
463 // exact crate name and a possibly an exact hash.
465 // During this step, we can filter all found libraries based on the
466 // name and id found in the crate id (we ignore the path portion for
467 // filename matching), as well as the exact hash (if specified). If we
468 // end up having many candidates, we must look at the metadata to
469 // perform exact matches against hashes/crate ids. Note that opening up
470 // the metadata is where we do an exact match against the full contents
471 // of the crate id (path/name/id).
473 // The goal of this step is to look at as little metadata as possible.
474 self.filesearch.search(|path, kind| {
475 let file = match path.file_name().and_then(|s| s.to_str()) {
476 None => return FileDoesntMatch,
479 let (hash, found_kind) =
480 if file.starts_with(&rlib_prefix) && file.ends_with(".rlib") {
481 (&file[(rlib_prefix.len())..(file.len() - ".rlib".len())], CrateFlavor::Rlib)
482 } else if file.starts_with(&rlib_prefix) && file.ends_with(".rmeta") {
483 (&file[(rlib_prefix.len())..(file.len() - ".rmeta".len())], CrateFlavor::Rmeta)
484 } else if file.starts_with(&dylib_prefix) &&
485 file.ends_with(&dypair.1) {
486 (&file[(dylib_prefix.len())..(file.len() - dypair.1.len())], CrateFlavor::Dylib)
488 if file.starts_with(&staticlib_prefix) && file.ends_with(&staticpair.1) {
489 staticlibs.push(CrateMismatch {
490 path: path.to_path_buf(),
491 got: "static".to_string(),
494 return FileDoesntMatch;
496 info!("lib candidate: {}", path.display());
498 let hash_str = hash.to_string();
499 let slot = candidates.entry(hash_str)
500 .or_insert_with(|| (FxHashMap(), FxHashMap(), FxHashMap()));
501 let (ref mut rlibs, ref mut rmetas, ref mut dylibs) = *slot;
502 fs::canonicalize(path)
505 CrateFlavor::Rlib => { rlibs.insert(p, kind); }
506 CrateFlavor::Rmeta => { rmetas.insert(p, kind); }
507 CrateFlavor::Dylib => { dylibs.insert(p, kind); }
511 .unwrap_or(FileDoesntMatch)
513 self.rejected_via_kind.extend(staticlibs);
515 // We have now collected all known libraries into a set of candidates
516 // keyed of the filename hash listed. For each filename, we also have a
517 // list of rlibs/dylibs that apply. Here, we map each of these lists
518 // (per hash), to a Library candidate for returning.
520 // A Library candidate is created if the metadata for the set of
521 // libraries corresponds to the crate id and hash criteria that this
522 // search is being performed for.
523 let mut libraries = FxHashMap();
524 for (_hash, (rlibs, rmetas, dylibs)) in candidates {
526 let rlib = self.extract_one(rlibs, CrateFlavor::Rlib, &mut slot);
527 let rmeta = self.extract_one(rmetas, CrateFlavor::Rmeta, &mut slot);
528 let dylib = self.extract_one(dylibs, CrateFlavor::Dylib, &mut slot);
529 if let Some((h, m)) = slot {
540 // Having now translated all relevant found hashes into libraries, see
541 // what we've got and figure out if we found multiple candidates for
543 match libraries.len() {
545 1 => Some(libraries.into_iter().next().unwrap().1),
547 let mut err = struct_span_err!(self.sess,
550 "multiple matching crates for `{}`",
552 err.note("candidates:");
553 for (_, lib) in libraries {
554 if let Some((ref p, _)) = lib.dylib {
555 err.note(&format!("path: {}", p.display()));
557 if let Some((ref p, _)) = lib.rlib {
558 err.note(&format!("path: {}", p.display()));
560 note_crate_name(&mut err, &lib.metadata.get_root().name.as_str());
568 // Attempts to extract *one* library from the set `m`. If the set has no
569 // elements, `None` is returned. If the set has more than one element, then
570 // the errors and notes are emitted about the set of libraries.
572 // With only one library in the set, this function will extract it, and then
573 // read the metadata from it if `*slot` is `None`. If the metadata couldn't
574 // be read, it is assumed that the file isn't a valid rust library (no
575 // errors are emitted).
576 fn extract_one(&mut self,
577 m: FxHashMap<PathBuf, PathKind>,
579 slot: &mut Option<(Svh, MetadataBlob)>)
580 -> Option<(PathBuf, PathKind)> {
581 let mut ret: Option<(PathBuf, PathKind)> = None;
585 // FIXME(#10786): for an optimization, we only read one of the
586 // libraries' metadata sections. In theory we should
587 // read both, but reading dylib metadata is quite
591 } else if m.len() == 1 {
592 return Some(m.into_iter().next().unwrap());
596 let mut err: Option<DiagnosticBuilder> = None;
597 for (lib, kind) in m {
598 info!("{} reading metadata from: {}", flavor, lib.display());
599 let (hash, metadata) = match get_metadata_section(self.target, flavor, &lib) {
601 if let Some(h) = self.crate_matches(&blob, &lib) {
604 info!("metadata mismatch");
609 info!("no metadata found: {}", err);
613 // If we see multiple hashes, emit an error about duplicate candidates.
614 if slot.as_ref().map_or(false, |s| s.0 != hash) {
615 let mut e = struct_span_err!(self.sess,
618 "multiple {} candidates for `{}` found",
621 e.span_note(self.span,
622 &format!(r"candidate #1: {}",
627 if let Some(ref mut e) = err {
636 err.as_mut().unwrap().span_note(self.span,
637 &format!(r"candidate #{}: {}",
643 // Ok so at this point we've determined that `(lib, kind)` above is
644 // a candidate crate to load, and that `slot` is either none (this
645 // is the first crate of its kind) or if some the previous path has
646 // the exact same hash (e.g. it's the exact same crate).
648 // In principle these two candidate crates are exactly the same so
649 // we can choose either of them to link. As a stupidly gross hack,
650 // however, we favor crate in the sysroot.
652 // You can find more info in rust-lang/rust#39518 and various linked
653 // issues, but the general gist is that during testing libstd the
654 // compilers has two candidates to choose from: one in the sysroot
655 // and one in the deps folder. These two crates are the exact same
656 // crate but if the compiler chooses the one in the deps folder
657 // it'll cause spurious errors on Windows.
659 // As a result, we favor the sysroot crate here. Note that the
660 // candidates are all canonicalized, so we canonicalize the sysroot
662 if let Some((ref prev, _)) = ret {
663 let sysroot = self.sess.sysroot();
664 let sysroot = sysroot.canonicalize()
665 .unwrap_or(sysroot.to_path_buf());
666 if prev.starts_with(&sysroot) {
670 *slot = Some((hash, metadata));
671 ret = Some((lib, kind));
682 fn crate_matches(&mut self, metadata: &MetadataBlob, libpath: &Path) -> Option<Svh> {
683 let rustc_version = rustc_version();
684 let found_version = metadata.get_rustc_version();
685 if found_version != rustc_version {
686 info!("Rejecting via version: expected {} got {}",
689 self.rejected_via_version.push(CrateMismatch {
690 path: libpath.to_path_buf(),
696 let root = metadata.get_root();
697 if let Some(is_proc_macro) = self.is_proc_macro {
698 if root.macro_derive_registrar.is_some() != is_proc_macro {
703 if self.should_match_name {
704 if self.crate_name != root.name {
705 info!("Rejecting via crate name");
710 if root.triple != self.triple {
711 info!("Rejecting via crate triple: expected {} got {}",
714 self.rejected_via_triple.push(CrateMismatch {
715 path: libpath.to_path_buf(),
721 if let Some(myhash) = self.hash {
722 if *myhash != root.hash {
723 info!("Rejecting via hash: expected {} got {}", *myhash, root.hash);
724 self.rejected_via_hash.push(CrateMismatch {
725 path: libpath.to_path_buf(),
726 got: myhash.to_string(),
736 // Returns the corresponding (prefix, suffix) that files need to have for
738 fn dylibname(&self) -> (String, String) {
739 let t = &self.target;
740 (t.options.dll_prefix.clone(), t.options.dll_suffix.clone())
743 // Returns the corresponding (prefix, suffix) that files need to have for
745 fn staticlibname(&self) -> (String, String) {
746 let t = &self.target;
747 (t.options.staticlib_prefix.clone(), t.options.staticlib_suffix.clone())
750 fn find_commandline_library<'b, LOCS>(&mut self, locs: LOCS) -> Option<Library>
751 where LOCS: Iterator<Item = &'b String>
753 // First, filter out all libraries that look suspicious. We only accept
754 // files which actually exist that have the correct naming scheme for
756 let sess = self.sess;
757 let dylibname = self.dylibname();
758 let mut rlibs = FxHashMap();
759 let mut rmetas = FxHashMap();
760 let mut dylibs = FxHashMap();
762 let locs = locs.map(|l| PathBuf::from(l)).filter(|loc| {
764 sess.err(&format!("extern location for {} does not exist: {}",
769 let file = match loc.file_name().and_then(|s| s.to_str()) {
772 sess.err(&format!("extern location for {} is not a file: {}",
778 if file.starts_with("lib") &&
779 (file.ends_with(".rlib") || file.ends_with(".rmeta")) {
782 let (ref prefix, ref suffix) = dylibname;
783 if file.starts_with(&prefix[..]) && file.ends_with(&suffix[..]) {
788 self.rejected_via_filename.push(CrateMismatch {
796 // Now that we have an iterator of good candidates, make sure
797 // there's at most one rlib and at most one dylib.
799 if loc.file_name().unwrap().to_str().unwrap().ends_with(".rlib") {
800 rlibs.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
801 } else if loc.file_name().unwrap().to_str().unwrap().ends_with(".rmeta") {
802 rmetas.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
804 dylibs.insert(fs::canonicalize(&loc).unwrap(), PathKind::ExternFlag);
809 // Extract the rlib/dylib pair.
811 let rlib = self.extract_one(rlibs, CrateFlavor::Rlib, &mut slot);
812 let rmeta = self.extract_one(rmetas, CrateFlavor::Rmeta, &mut slot);
813 let dylib = self.extract_one(dylibs, CrateFlavor::Dylib, &mut slot);
815 if rlib.is_none() && rmeta.is_none() && dylib.is_none() {
819 Some((_, metadata)) => {
832 pub fn note_crate_name(err: &mut DiagnosticBuilder, name: &str) {
833 err.note(&format!("crate name: {}", name));
836 impl ArchiveMetadata {
837 fn new(ar: ArchiveRO) -> Option<ArchiveMetadata> {
839 let section = ar.iter()
840 .filter_map(|s| s.ok())
841 .find(|sect| sect.name() == Some(METADATA_FILENAME));
843 Some(s) => s.data() as *const [u8],
845 debug!("didn't find '{}' in the archive", METADATA_FILENAME);
851 Some(ArchiveMetadata {
857 pub fn as_slice<'a>(&'a self) -> &'a [u8] {
858 unsafe { &*self.data }
862 fn verify_decompressed_encoding_version(blob: &MetadataBlob,
864 -> Result<(), String> {
865 if !blob.is_compatible() {
866 Err((format!("incompatible metadata version found: '{}'",
867 filename.display())))
873 // Just a small wrapper to time how long reading metadata takes.
874 fn get_metadata_section(target: &Target,
877 -> Result<MetadataBlob, String> {
878 let start = Instant::now();
879 let ret = get_metadata_section_imp(target, flavor, filename);
880 info!("reading {:?} => {:?}",
881 filename.file_name().unwrap(),
886 fn get_metadata_section_imp(target: &Target,
889 -> Result<MetadataBlob, String> {
890 if !filename.exists() {
891 return Err(format!("no such file: '{}'", filename.display()));
893 if flavor == CrateFlavor::Rlib {
894 // Use ArchiveRO for speed here, it's backed by LLVM and uses mmap
895 // internally to read the file. We also avoid even using a memcpy by
896 // just keeping the archive along while the metadata is in use.
897 let archive = match ArchiveRO::open(filename) {
900 debug!("llvm didn't like `{}`", filename.display());
901 return Err(format!("failed to read rlib metadata: '{}'", filename.display()));
904 return match ArchiveMetadata::new(archive).map(|ar| MetadataBlob::Archive(ar)) {
905 None => Err(format!("failed to read rlib metadata: '{}'", filename.display())),
907 verify_decompressed_encoding_version(&blob, filename)?;
911 } else if flavor == CrateFlavor::Rmeta {
912 let mut file = File::open(filename).map_err(|_|
913 format!("could not open file: '{}'", filename.display()))?;
914 let mut buf = vec![];
915 file.read_to_end(&mut buf).map_err(|_|
916 format!("failed to read rlib metadata: '{}'", filename.display()))?;
917 let blob = MetadataBlob::Raw(buf);
918 verify_decompressed_encoding_version(&blob, filename)?;
922 let buf = common::path2cstr(filename);
923 let mb = llvm::LLVMRustCreateMemoryBufferWithContentsOfFile(buf.as_ptr());
924 if mb as isize == 0 {
925 return Err(format!("error reading library: '{}'", filename.display()));
927 let of = match ObjectFile::new(mb) {
930 return Err((format!("provided path not an object file: '{}'", filename.display())))
933 let si = mk_section_iter(of.llof);
934 while llvm::LLVMIsSectionIteratorAtEnd(of.llof, si.llsi) == False {
935 let mut name_buf = ptr::null();
936 let name_len = llvm::LLVMRustGetSectionName(si.llsi, &mut name_buf);
937 let name = slice::from_raw_parts(name_buf as *const u8, name_len as usize).to_vec();
938 let name = String::from_utf8(name).unwrap();
939 debug!("get_metadata_section: name {}", name);
940 if read_meta_section_name(target) == name {
941 let cbuf = llvm::LLVMGetSectionContents(si.llsi);
942 let csz = llvm::LLVMGetSectionSize(si.llsi) as usize;
943 let cvbuf: *const u8 = cbuf as *const u8;
944 let vlen = METADATA_HEADER.len();
945 debug!("checking {} bytes of metadata-version stamp", vlen);
946 let minsz = cmp::min(vlen, csz);
947 let buf0 = slice::from_raw_parts(cvbuf, minsz);
948 let version_ok = buf0 == METADATA_HEADER;
950 return Err((format!("incompatible metadata version found: '{}'",
951 filename.display())));
954 let cvbuf1 = cvbuf.offset(vlen as isize);
955 debug!("inflating {} bytes of compressed metadata", csz - vlen);
956 let bytes = slice::from_raw_parts(cvbuf1, csz - vlen);
957 match flate::inflate_bytes(bytes) {
959 let blob = MetadataBlob::Inflated(inflated);
960 verify_decompressed_encoding_version(&blob, filename)?;
966 llvm::LLVMMoveToNextSection(si.llsi);
968 Err(format!("metadata not found: '{}'", filename.display()))
972 pub fn meta_section_name(target: &Target) -> &'static str {
975 // When using link.exe it was seen that the section name `.note.rustc`
976 // was getting shortened to `.note.ru`, and according to the PE and COFF
979 // > Executable images do not use a string table and do not support
980 // > section names longer than 8 characters
982 // https://msdn.microsoft.com/en-us/library/windows/hardware/gg463119.aspx
984 // As a result, we choose a slightly shorter name! As to why
985 // `.note.rustc` works on MinGW, that's another good question...
987 if target.options.is_like_osx {
994 pub fn read_meta_section_name(_target: &Target) -> &'static str {
998 // A diagnostic function for dumping crate metadata to an output stream
999 pub fn list_file_metadata(target: &Target, path: &Path, out: &mut io::Write) -> io::Result<()> {
1000 let filename = path.file_name().unwrap().to_str().unwrap();
1001 let flavor = if filename.ends_with(".rlib") {
1003 } else if filename.ends_with(".rmeta") {
1008 match get_metadata_section(target, flavor, path) {
1009 Ok(metadata) => metadata.list_crate_metadata(out),
1010 Err(msg) => write!(out, "{}\n", msg),