1 // Copyright 2012 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 //! When translating a crate name to a crate on the filesystem, we all of a
57 //! sudden need to take into account both rlibs and dylibs! Linkage later on may
58 //! use either one of these files, as each has their pros/cons. The job of crate
59 //! loading is to discover what's possible by finding all candidates.
61 //! Most parts of this loading systems keep the dylib/rlib as just separate
66 //! We can't exactly scan your whole hard drive when looking for dependencies,
67 //! so we need to places to look. Currently the compiler will implicitly add the
68 //! target lib search path ($prefix/lib/rustlib/$target/lib) to any compilation,
69 //! and otherwise all -L flags are added to the search paths.
71 //! ## What criterion to select on?
73 //! This a pretty tricky area of loading crates. Given a file, how do we know
74 //! whether it's the right crate? Currently, the rules look along these lines:
76 //! 1. Does the filename match an rlib/dylib pattern? That is to say, does the
77 //! filename have the right prefix/suffix?
78 //! 2. Does the filename have the right prefix for the crate name being queried?
79 //! This is filtering for files like `libfoo*.rlib` and such.
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 too 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:
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::loader or metadata::creader for all the juicy details!
215 use back::archive::{METADATA_FILENAME};
217 use driver::session::Session;
219 use llvm::{False, ObjectFile, mk_section_iter};
220 use llvm::archive_ro::ArchiveRO;
221 use metadata::cstore::{MetadataBlob, MetadataVec, MetadataArchive};
222 use metadata::decoder;
223 use metadata::encoder;
224 use metadata::filesearch::{FileSearch, FileMatches, FileDoesntMatch};
226 use syntax::codemap::Span;
227 use syntax::diagnostic::SpanHandler;
230 use std::c_str::ToCStr;
232 use std::io::fs::PathExtensions;
239 use std::collections::{HashMap, HashSet};
243 pub static MACOS_DLL_PREFIX: &'static str = "lib";
244 pub static MACOS_DLL_SUFFIX: &'static str = ".dylib";
246 pub static WIN32_DLL_PREFIX: &'static str = "";
247 pub static WIN32_DLL_SUFFIX: &'static str = ".dll";
249 pub static LINUX_DLL_PREFIX: &'static str = "lib";
250 pub static LINUX_DLL_SUFFIX: &'static str = ".so";
252 pub static FREEBSD_DLL_PREFIX: &'static str = "lib";
253 pub static FREEBSD_DLL_SUFFIX: &'static str = ".so";
255 pub static DRAGONFLY_DLL_PREFIX: &'static str = "lib";
256 pub static DRAGONFLY_DLL_SUFFIX: &'static str = ".so";
258 pub static ANDROID_DLL_PREFIX: &'static str = "lib";
259 pub static ANDROID_DLL_SUFFIX: &'static str = ".so";
261 pub struct CrateMismatch {
266 pub struct Context<'a> {
267 pub sess: &'a Session,
270 pub crate_name: &'a str,
271 pub hash: Option<&'a Svh>,
274 pub filesearch: FileSearch<'a>,
275 pub root: &'a Option<CratePaths>,
276 pub rejected_via_hash: Vec<CrateMismatch>,
277 pub rejected_via_triple: Vec<CrateMismatch>,
278 pub should_match_name: bool,
282 pub dylib: Option<Path>,
283 pub rlib: Option<Path>,
284 pub metadata: MetadataBlob,
287 pub struct ArchiveMetadata {
289 // See comments in ArchiveMetadata::new for why this is static
293 pub struct CratePaths {
295 pub dylib: Option<Path>,
296 pub rlib: Option<Path>
300 fn paths(&self) -> Vec<Path> {
301 match (&self.dylib, &self.rlib) {
302 (&None, &None) => vec!(),
303 (&Some(ref p), &None) |
304 (&None, &Some(ref p)) => vec!(p.clone()),
305 (&Some(ref p1), &Some(ref p2)) => vec!(p1.clone(), p2.clone()),
310 impl<'a> Context<'a> {
311 pub fn maybe_load_library_crate(&mut self) -> Option<Library> {
312 self.find_library_crate()
315 pub fn load_library_crate(&mut self) -> Library {
316 match self.find_library_crate() {
319 self.report_load_errs();
325 pub fn report_load_errs(&mut self) {
326 let message = if self.rejected_via_hash.len() > 0 {
327 format!("found possibly newer version of crate `{}`",
329 } else if self.rejected_via_triple.len() > 0 {
330 format!("found incorrect triple for crate `{}`", self.ident)
332 format!("can't find crate for `{}`", self.ident)
334 let message = match self.root {
336 &Some(ref r) => format!("{} which `{}` depends on",
339 self.sess.span_err(self.span, message.as_slice());
341 let mismatches = self.rejected_via_triple.iter();
342 if self.rejected_via_triple.len() > 0 {
343 self.sess.span_note(self.span,
344 format!("expected triple of {}",
345 self.triple).as_slice());
346 for (i, &CrateMismatch{ ref path, ref got }) in mismatches.enumerate() {
347 self.sess.fileline_note(self.span,
348 format!("crate `{}` path {}{}, triple {}: {}",
349 self.ident, "#", i+1, got, path.display()).as_slice());
352 if self.rejected_via_hash.len() > 0 {
353 self.sess.span_note(self.span, "perhaps this crate needs \
355 let mismatches = self.rejected_via_hash.iter();
356 for (i, &CrateMismatch{ ref path, .. }) in mismatches.enumerate() {
357 self.sess.fileline_note(self.span,
358 format!("crate `{}` path {}{}: {}",
359 self.ident, "#", i+1, path.display()).as_slice());
364 for (i, path) in r.paths().iter().enumerate() {
365 self.sess.fileline_note(self.span,
366 format!("crate `{}` path #{}: {}",
367 r.ident, i+1, path.display()).as_slice());
372 self.sess.abort_if_errors();
375 fn find_library_crate(&mut self) -> Option<Library> {
376 // If an SVH is specified, then this is a transitive dependency that
377 // must be loaded via -L plus some filtering.
378 if self.hash.is_none() {
379 self.should_match_name = false;
380 match self.find_commandline_library() {
381 Some(l) => return Some(l),
384 self.should_match_name = true;
387 let dypair = self.dylibname();
389 // want: crate_name.dir_part() + prefix + crate_name.file_part + "-"
390 let dylib_prefix = dypair.map(|(prefix, _)| {
391 format!("{}{}", prefix, self.crate_name)
393 let rlib_prefix = format!("lib{}", self.crate_name);
395 let mut candidates = HashMap::new();
397 // First, find all possible candidate rlibs and dylibs purely based on
398 // the name of the files themselves. We're trying to match against an
399 // exact crate name and a possibly an exact hash.
401 // During this step, we can filter all found libraries based on the
402 // name and id found in the crate id (we ignore the path portion for
403 // filename matching), as well as the exact hash (if specified). If we
404 // end up having many candidates, we must look at the metadata to
405 // perform exact matches against hashes/crate ids. Note that opening up
406 // the metadata is where we do an exact match against the full contents
407 // of the crate id (path/name/id).
409 // The goal of this step is to look at as little metadata as possible.
410 self.filesearch.search(|path| {
411 let file = match path.filename_str() {
412 None => return FileDoesntMatch,
415 let (hash, rlib) = if file.starts_with(rlib_prefix.as_slice()) &&
416 file.ends_with(".rlib") {
417 (file.slice(rlib_prefix.len(), file.len() - ".rlib".len()),
419 } else if dypair.map_or(false, |(_, suffix)| {
420 file.starts_with(dylib_prefix.get_ref().as_slice()) &&
421 file.ends_with(suffix)
423 let (_, suffix) = dypair.unwrap();
424 let dylib_prefix = dylib_prefix.get_ref().as_slice();
425 (file.slice(dylib_prefix.len(), file.len() - suffix.len()),
428 return FileDoesntMatch
430 info!("lib candidate: {}", path.display());
431 let slot = candidates.find_or_insert_with(hash.to_string(), |_| {
432 (HashSet::new(), HashSet::new())
434 let (ref mut rlibs, ref mut dylibs) = *slot;
436 rlibs.insert(fs::realpath(path).unwrap());
438 dylibs.insert(fs::realpath(path).unwrap());
443 // We have now collected all known libraries into a set of candidates
444 // keyed of the filename hash listed. For each filename, we also have a
445 // list of rlibs/dylibs that apply. Here, we map each of these lists
446 // (per hash), to a Library candidate for returning.
448 // A Library candidate is created if the metadata for the set of
449 // libraries corresponds to the crate id and hash criteria that this
450 // search is being performed for.
451 let mut libraries = Vec::new();
452 for (_hash, (rlibs, dylibs)) in candidates.move_iter() {
453 let mut metadata = None;
454 let rlib = self.extract_one(rlibs, "rlib", &mut metadata);
455 let dylib = self.extract_one(dylibs, "dylib", &mut metadata);
458 libraries.push(Library {
468 // Having now translated all relevant found hashes into libraries, see
469 // what we've got and figure out if we found multiple candidates for
471 match libraries.len() {
473 1 => Some(libraries.move_iter().next().unwrap()),
475 self.sess.span_err(self.span,
476 format!("multiple matching crates for `{}`",
477 self.crate_name).as_slice());
478 self.sess.note("candidates:");
479 for lib in libraries.iter() {
482 self.sess.note(format!("path: {}",
483 p.display()).as_slice());
489 self.sess.note(format!("path: {}",
490 p.display()).as_slice());
494 let data = lib.metadata.as_slice();
495 let name = decoder::get_crate_name(data);
496 note_crate_name(self.sess.diagnostic(), name.as_slice());
503 // Attempts to extract *one* library from the set `m`. If the set has no
504 // elements, `None` is returned. If the set has more than one element, then
505 // the errors and notes are emitted about the set of libraries.
507 // With only one library in the set, this function will extract it, and then
508 // read the metadata from it if `*slot` is `None`. If the metadata couldn't
509 // be read, it is assumed that the file isn't a valid rust library (no
510 // errors are emitted).
511 fn extract_one(&mut self, m: HashSet<Path>, flavor: &str,
512 slot: &mut Option<MetadataBlob>) -> Option<Path> {
513 let mut ret = None::<Path>;
517 // FIXME(#10786): for an optimization, we only read one of the
518 // library's metadata sections. In theory we should
519 // read both, but reading dylib metadata is quite
523 } else if m.len() == 1 {
524 return Some(m.move_iter().next().unwrap())
528 for lib in m.move_iter() {
529 info!("{} reading metadata from: {}", flavor, lib.display());
530 let metadata = match get_metadata_section(self.os, &lib) {
532 if self.crate_matches(blob.as_slice(), &lib) {
535 info!("metadata mismatch");
540 info!("no metadata found");
545 self.sess.span_err(self.span,
546 format!("multiple {} candidates for `{}` \
549 self.crate_name).as_slice());
550 self.sess.span_note(self.span,
551 format!(r"candidate #1: {}",
553 .display()).as_slice());
559 self.sess.span_note(self.span,
560 format!(r"candidate #{}: {}", error,
561 lib.display()).as_slice());
564 *slot = Some(metadata);
567 return if error > 0 {None} else {ret}
570 fn crate_matches(&mut self, crate_data: &[u8], libpath: &Path) -> bool {
571 if self.should_match_name {
572 match decoder::maybe_get_crate_name(crate_data) {
573 Some(ref name) if self.crate_name == name.as_slice() => {}
574 _ => { info!("Rejecting via crate name"); return false }
577 let hash = match decoder::maybe_get_crate_hash(crate_data) {
578 Some(hash) => hash, None => {
579 info!("Rejecting via lack of crate hash");
584 let triple = match decoder::get_crate_triple(crate_data) {
585 None => { debug!("triple not present"); return false }
588 if triple.as_slice() != self.triple {
589 info!("Rejecting via crate triple: expected {} got {}", self.triple, triple);
590 self.rejected_via_triple.push(CrateMismatch {
591 path: libpath.clone(),
592 got: triple.to_string()
601 info!("Rejecting via hash: expected {} got {}", *myhash, hash);
602 self.rejected_via_hash.push(CrateMismatch {
603 path: libpath.clone(),
604 got: myhash.as_str().to_string()
615 // Returns the corresponding (prefix, suffix) that files need to have for
617 fn dylibname(&self) -> Option<(&'static str, &'static str)> {
619 abi::OsWindows => Some((WIN32_DLL_PREFIX, WIN32_DLL_SUFFIX)),
620 abi::OsMacos => Some((MACOS_DLL_PREFIX, MACOS_DLL_SUFFIX)),
621 abi::OsLinux => Some((LINUX_DLL_PREFIX, LINUX_DLL_SUFFIX)),
622 abi::OsAndroid => Some((ANDROID_DLL_PREFIX, ANDROID_DLL_SUFFIX)),
623 abi::OsFreebsd => Some((FREEBSD_DLL_PREFIX, FREEBSD_DLL_SUFFIX)),
624 abi::OsDragonfly => Some((DRAGONFLY_DLL_PREFIX, DRAGONFLY_DLL_SUFFIX)),
629 fn find_commandline_library(&mut self) -> Option<Library> {
630 let locs = match self.sess.opts.externs.find_equiv(&self.crate_name) {
635 // First, filter out all libraries that look suspicious. We only accept
636 // files which actually exist that have the correct naming scheme for
638 let sess = self.sess;
639 let dylibname = self.dylibname();
640 let mut locs = locs.iter().map(|l| Path::new(l.as_slice())).filter(|loc| {
642 sess.err(format!("extern location does not exist: {}",
643 loc.display()).as_slice());
646 let file = loc.filename_str().unwrap();
647 if file.starts_with("lib") && file.ends_with(".rlib") {
651 Some((prefix, suffix)) => {
652 if file.starts_with(prefix) && file.ends_with(suffix) {
659 sess.err(format!("extern location is of an unknown type: {}",
660 loc.display()).as_slice());
664 // Now that we have an iterator of good candidates, make sure there's at
665 // most one rlib and at most one dylib.
666 let mut rlibs = HashSet::new();
667 let mut dylibs = HashSet::new();
669 if loc.filename_str().unwrap().ends_with(".rlib") {
670 rlibs.insert(fs::realpath(&loc).unwrap());
672 dylibs.insert(fs::realpath(&loc).unwrap());
676 // Extract the rlib/dylib pair.
677 let mut metadata = None;
678 let rlib = self.extract_one(rlibs, "rlib", &mut metadata);
679 let dylib = self.extract_one(dylibs, "dylib", &mut metadata);
681 if rlib.is_none() && dylib.is_none() { return None }
683 Some(metadata) => Some(Library {
693 pub fn note_crate_name(diag: &SpanHandler, name: &str) {
694 diag.handler().note(format!("crate name: {}", name).as_slice());
697 impl ArchiveMetadata {
698 fn new(ar: ArchiveRO) -> Option<ArchiveMetadata> {
699 let data: &'static [u8] = {
700 let data = match ar.read(METADATA_FILENAME) {
703 debug!("didn't find '{}' in the archive", METADATA_FILENAME);
707 // This data is actually a pointer inside of the archive itself, but
708 // we essentially want to cache it because the lookup inside the
709 // archive is a fairly expensive operation (and it's queried for
710 // *very* frequently). For this reason, we transmute it to the
711 // static lifetime to put into the struct. Note that the buffer is
712 // never actually handed out with a static lifetime, but rather the
713 // buffer is loaned with the lifetime of this containing object.
714 // Hence, we're guaranteed that the buffer will never be used after
715 // this object is dead, so this is a safe operation to transmute and
716 // store the data as a static buffer.
717 unsafe { mem::transmute(data) }
719 Some(ArchiveMetadata {
725 pub fn as_slice<'a>(&'a self) -> &'a [u8] { self.data }
728 // Just a small wrapper to time how long reading metadata takes.
729 fn get_metadata_section(os: abi::Os, filename: &Path) -> Result<MetadataBlob, String> {
730 let start = time::precise_time_ns();
731 let ret = get_metadata_section_imp(os, filename);
732 info!("reading {} => {}ms", filename.filename_display(),
733 (time::precise_time_ns() - start) / 1000000);
737 fn get_metadata_section_imp(os: abi::Os, filename: &Path) -> Result<MetadataBlob, String> {
738 if !filename.exists() {
739 return Err(format!("no such file: '{}'", filename.display()));
741 if filename.filename_str().unwrap().ends_with(".rlib") {
742 // Use ArchiveRO for speed here, it's backed by LLVM and uses mmap
743 // internally to read the file. We also avoid even using a memcpy by
744 // just keeping the archive along while the metadata is in use.
745 let archive = match ArchiveRO::open(filename) {
748 debug!("llvm didn't like `{}`", filename.display());
749 return Err(format!("failed to read rlib metadata: '{}'",
750 filename.display()));
753 return match ArchiveMetadata::new(archive).map(|ar| MetadataArchive(ar)) {
755 return Err((format!("failed to read rlib metadata: '{}'",
756 filename.display())))
758 Some(blob) => return Ok(blob)
762 let mb = filename.with_c_str(|buf| {
763 llvm::LLVMRustCreateMemoryBufferWithContentsOfFile(buf)
766 return Err(format!("error reading library: '{}'",
769 let of = match ObjectFile::new(mb) {
772 return Err((format!("provided path not an object file: '{}'",
773 filename.display())))
776 let si = mk_section_iter(of.llof);
777 while llvm::LLVMIsSectionIteratorAtEnd(of.llof, si.llsi) == False {
778 let mut name_buf = ptr::null();
779 let name_len = llvm::LLVMRustGetSectionName(si.llsi, &mut name_buf);
780 let name = string::raw::from_buf_len(name_buf as *const u8,
782 debug!("get_metadata_section: name {}", name);
783 if read_meta_section_name(os).as_slice() == name.as_slice() {
784 let cbuf = llvm::LLVMGetSectionContents(si.llsi);
785 let csz = llvm::LLVMGetSectionSize(si.llsi) as uint;
787 Err(format!("metadata not found: '{}'", filename.display()));
788 let cvbuf: *const u8 = mem::transmute(cbuf);
789 let vlen = encoder::metadata_encoding_version.len();
790 debug!("checking {} bytes of metadata-version stamp",
792 let minsz = cmp::min(vlen, csz);
793 let version_ok = slice::raw::buf_as_slice(cvbuf, minsz,
794 |buf0| buf0 == encoder::metadata_encoding_version);
796 return Err((format!("incompatible metadata version found: '{}'",
797 filename.display())));
800 let cvbuf1 = cvbuf.offset(vlen as int);
801 debug!("inflating {} bytes of compressed metadata",
803 slice::raw::buf_as_slice(cvbuf1, csz-vlen, |bytes| {
804 match flate::inflate_bytes(bytes) {
805 Some(inflated) => found = Ok(MetadataVec(inflated)),
808 Err(format!("failed to decompress \
818 llvm::LLVMMoveToNextSection(si.llsi);
820 return Err(format!("metadata not found: '{}'", filename.display()));
824 pub fn meta_section_name(os: abi::Os) -> Option<&'static str> {
826 abi::OsMacos => Some("__DATA,__note.rustc"),
827 abi::OsiOS => Some("__DATA,__note.rustc"),
828 abi::OsWindows => Some(".note.rustc"),
829 abi::OsLinux => Some(".note.rustc"),
830 abi::OsAndroid => Some(".note.rustc"),
831 abi::OsFreebsd => Some(".note.rustc"),
832 abi::OsDragonfly => Some(".note.rustc"),
836 pub fn read_meta_section_name(os: abi::Os) -> &'static str {
838 abi::OsMacos => "__note.rustc",
839 abi::OsiOS => unreachable!(),
840 abi::OsWindows => ".note.rustc",
841 abi::OsLinux => ".note.rustc",
842 abi::OsAndroid => ".note.rustc",
843 abi::OsFreebsd => ".note.rustc",
844 abi::OsDragonfly => ".note.rustc"
848 // A diagnostic function for dumping crate metadata to an output stream
849 pub fn list_file_metadata(os: abi::Os, path: &Path,
850 out: &mut io::Writer) -> io::IoResult<()> {
851 match get_metadata_section(os, path) {
852 Ok(bytes) => decoder::list_crate_metadata(bytes.as_slice(), out),
854 write!(out, "{}\n", msg)