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 #![allow(non_camel_case_types)]
13 //! Validates all used crates and extern libraries and loads their metadata
15 use common::rustc_version;
16 use cstore::{self, CStore, CrateSource, MetadataBlob};
18 use loader::{self, CratePaths};
20 use rustc::back::svh::Svh;
21 use rustc::session::{config, Session};
22 use rustc::session::search_paths::PathKind;
23 use rustc::middle::cstore::{CrateStore, validate_crate_name};
24 use rustc::util::nodemap::FnvHashMap;
25 use rustc::front::map as hir_map;
27 use std::cell::{RefCell, Cell};
28 use std::path::PathBuf;
34 use syntax::codemap::{self, Span, mk_sp, Pos};
37 use syntax::attr::AttrMetaMethods;
38 use syntax::errors::FatalError;
39 use syntax::parse::token::InternedString;
40 use syntax::util::small_vector::SmallVector;
41 use rustc_front::intravisit::Visitor;
45 pub struct LocalCrateReader<'a, 'b:'a> {
48 creader: CrateReader<'a>,
49 ast_map: &'a hir_map::Map<'b>,
52 pub struct CrateReader<'a> {
55 next_crate_num: ast::CrateNum,
56 foreign_item_map: FnvHashMap<String, Vec<ast::NodeId>>,
59 impl<'a, 'b, 'hir> Visitor<'hir> for LocalCrateReader<'a, 'b> {
60 fn visit_item(&mut self, a: &'hir hir::Item) {
65 fn dump_crates(cstore: &CStore) {
66 info!("resolved crates:");
67 cstore.iter_crate_data_origins(|_, data, opt_source| {
68 info!(" name: {}", data.name());
69 info!(" cnum: {}", data.cnum);
70 info!(" hash: {}", data.hash());
71 info!(" reqd: {}", data.explicitly_linked.get());
73 let CrateSource { dylib, rlib, cnum: _ } = cs;
74 dylib.map(|dl| info!(" dylib: {}", dl.0.display()));
75 rlib.map(|rl| info!(" rlib: {}", rl.0.display()));
80 fn should_link(i: &ast::Item) -> bool {
81 !attr::contains_name(&i.attrs, "no_link")
84 fn should_link_hir(i: &hir::Item) -> bool {
85 !attr::contains_name(&i.attrs, "no_link")
95 fn register_native_lib(sess: &Session,
99 kind: cstore::NativeLibraryKind) {
103 span_err!(sess, span, E0454,
104 "#[link(name = \"\")] given with empty name");
107 sess.err("empty library name given via `-l`");
112 let is_osx = sess.target.target.options.is_like_osx;
113 if kind == cstore::NativeFramework && !is_osx {
114 let msg = "native frameworks are only available on OSX targets";
117 span_err!(sess, span, E0455,
120 None => sess.err(msg),
123 cstore.add_used_library(name, kind);
126 // Extra info about a crate loaded for plugins or exported macros.
127 struct ExtensionCrate {
129 dylib: Option<PathBuf>,
134 Registered(Rc<cstore::crate_metadata>),
139 pub fn as_slice<'a>(&'a self) -> &'a [u8] {
141 PMDSource::Registered(ref cmd) => cmd.data(),
142 PMDSource::Owned(ref mdb) => mdb.as_slice(),
147 impl<'a> CrateReader<'a> {
148 pub fn new(sess: &'a Session, cstore: &'a CStore) -> CrateReader<'a> {
152 next_crate_num: cstore.next_crate_num(),
153 foreign_item_map: FnvHashMap(),
157 fn extract_crate_info(&self, i: &ast::Item) -> Option<CrateInfo> {
159 ast::ItemExternCrate(ref path_opt) => {
160 debug!("resolving extern crate stmt. ident: {} path_opt: {:?}",
162 let name = match *path_opt {
164 validate_crate_name(Some(self.sess), &name.as_str(),
168 None => i.ident.to_string(),
171 ident: i.ident.to_string(),
174 should_link: should_link(i),
181 // Dup of the above, but for the hir
182 fn extract_crate_info_hir(&self, i: &hir::Item) -> Option<CrateInfo> {
184 hir::ItemExternCrate(ref path_opt) => {
185 debug!("resolving extern crate stmt. ident: {} path_opt: {:?}",
187 let name = match *path_opt {
189 validate_crate_name(Some(self.sess), &name.as_str(),
193 None => i.name.to_string(),
196 ident: i.name.to_string(),
199 should_link: should_link_hir(i),
206 fn existing_match(&self, name: &str, hash: Option<&Svh>, kind: PathKind)
207 -> Option<ast::CrateNum> {
209 self.cstore.iter_crate_data(|cnum, data| {
210 if data.name != name { return }
213 Some(hash) if *hash == data.hash() => { ret = Some(cnum); return }
218 // When the hash is None we're dealing with a top-level dependency
219 // in which case we may have a specification on the command line for
220 // this library. Even though an upstream library may have loaded
221 // something of the same name, we have to make sure it was loaded
222 // from the exact same location as well.
224 // We're also sure to compare *paths*, not actual byte slices. The
225 // `source` stores paths which are normalized which may be different
226 // from the strings on the command line.
227 let source = self.cstore.used_crate_source(cnum);
228 if let Some(locs) = self.sess.opts.externs.get(name) {
229 let found = locs.iter().any(|l| {
230 let l = fs::canonicalize(l).ok();
231 source.dylib.as_ref().map(|p| &p.0) == l.as_ref() ||
232 source.rlib.as_ref().map(|p| &p.0) == l.as_ref()
240 // Alright, so we've gotten this far which means that `data` has the
241 // right name, we don't have a hash, and we don't have a --extern
242 // pointing for ourselves. We're still not quite yet done because we
243 // have to make sure that this crate was found in the crate lookup
244 // path (this is a top-level dependency) as we don't want to
245 // implicitly load anything inside the dependency lookup path.
246 let prev_kind = source.dylib.as_ref().or(source.rlib.as_ref())
248 if ret.is_none() && (prev_kind == kind || prev_kind == PathKind::All) {
255 fn verify_rustc_version(&self,
258 metadata: &MetadataBlob) {
259 let crate_rustc_version = decoder::crate_rustc_version(metadata.as_slice());
260 if crate_rustc_version != Some(rustc_version()) {
261 span_fatal!(self.sess, span, E0514,
262 "the crate `{}` has been compiled with {}, which is \
263 incompatible with this version of rustc",
266 .as_ref().map(|s|&**s)
267 .unwrap_or("an old version of rustc")
272 fn register_crate(&mut self,
273 root: &Option<CratePaths>,
277 lib: loader::Library,
278 explicitly_linked: bool)
279 -> (ast::CrateNum, Rc<cstore::crate_metadata>,
280 cstore::CrateSource) {
281 self.verify_rustc_version(name, span, &lib.metadata);
283 // Claim this crate number and cache it
284 let cnum = self.next_crate_num;
285 self.next_crate_num += 1;
287 // Stash paths for top-most crate locally if necessary.
288 let crate_paths = if root.is_none() {
290 ident: ident.to_string(),
291 dylib: lib.dylib.clone().map(|p| p.0),
292 rlib: lib.rlib.clone().map(|p| p.0),
297 // Maintain a reference to the top most crate.
298 let root = if root.is_some() { root } else { &crate_paths };
300 let loader::Library { dylib, rlib, metadata } = lib;
302 let cnum_map = self.resolve_crate_deps(root, metadata.as_slice(), span);
303 let staged_api = self.is_staged_api(metadata.as_slice());
305 let cmeta = Rc::new(cstore::crate_metadata {
306 name: name.to_string(),
307 local_path: RefCell::new(SmallVector::zero()),
308 local_def_path: RefCell::new(vec![]),
309 index: decoder::load_index(metadata.as_slice()),
310 xref_index: decoder::load_xrefs(metadata.as_slice()),
312 cnum_map: RefCell::new(cnum_map),
314 codemap_import_info: RefCell::new(vec![]),
316 staged_api: staged_api,
317 explicitly_linked: Cell::new(explicitly_linked),
320 let source = cstore::CrateSource {
326 self.cstore.set_crate_data(cnum, cmeta.clone());
327 self.cstore.add_used_crate_source(source.clone());
328 (cnum, cmeta, source)
331 fn is_staged_api(&self, data: &[u8]) -> bool {
332 let attrs = decoder::get_crate_attributes(data);
334 if attr.name() == "stable" || attr.name() == "unstable" {
341 fn resolve_crate(&mut self,
342 root: &Option<CratePaths>,
348 explicitly_linked: bool)
349 -> (ast::CrateNum, Rc<cstore::crate_metadata>,
350 cstore::CrateSource) {
352 Previous(ast::CrateNum),
353 Loaded(loader::Library),
355 let result = match self.existing_match(name, hash, kind) {
356 Some(cnum) => LookupResult::Previous(cnum),
358 let mut load_ctxt = loader::Context {
363 hash: hash.map(|a| &*a),
364 filesearch: self.sess.target_filesearch(kind),
365 target: &self.sess.target.target,
366 triple: &self.sess.opts.target_triple,
368 rejected_via_hash: vec!(),
369 rejected_via_triple: vec!(),
370 rejected_via_kind: vec!(),
371 should_match_name: true,
373 let library = load_ctxt.load_library_crate();
375 // In the case that we're loading a crate, but not matching
376 // against a hash, we could load a crate which has the same hash
377 // as an already loaded crate. If this is the case prevent
378 // duplicates by just using the first crate.
379 let meta_hash = decoder::get_crate_hash(library.metadata
381 let mut result = LookupResult::Loaded(library);
382 self.cstore.iter_crate_data(|cnum, data| {
383 if data.name() == name && meta_hash == data.hash() {
384 assert!(hash.is_none());
385 result = LookupResult::Previous(cnum);
393 LookupResult::Previous(cnum) => {
394 let data = self.cstore.get_crate_data(cnum);
395 if explicitly_linked && !data.explicitly_linked.get() {
396 data.explicitly_linked.set(explicitly_linked);
398 (cnum, data, self.cstore.used_crate_source(cnum))
400 LookupResult::Loaded(library) => {
401 self.register_crate(root, ident, name, span, library,
407 // Go through the crate metadata and load any crates that it references
408 fn resolve_crate_deps(&mut self,
409 root: &Option<CratePaths>,
410 cdata: &[u8], span : Span)
411 -> cstore::cnum_map {
412 debug!("resolving deps of external crate");
413 // The map from crate numbers in the crate we're resolving to local crate
415 decoder::get_crate_deps(cdata).iter().map(|dep| {
416 debug!("resolving dep crate {} hash: `{}`", dep.name, dep.hash);
417 let (local_cnum, _, _) = self.resolve_crate(root,
422 PathKind::Dependency,
423 dep.explicitly_linked);
424 (dep.cnum, local_cnum)
428 fn read_extension_crate(&mut self, span: Span, info: &CrateInfo) -> ExtensionCrate {
429 let target_triple = &self.sess.opts.target_triple[..];
430 let is_cross = target_triple != config::host_triple();
431 let mut should_link = info.should_link && !is_cross;
432 let mut target_only = false;
433 let ident = info.ident.clone();
434 let name = info.name.clone();
435 let mut load_ctxt = loader::Context {
439 crate_name: &name[..],
441 filesearch: self.sess.host_filesearch(PathKind::Crate),
442 target: &self.sess.host,
443 triple: config::host_triple(),
445 rejected_via_hash: vec!(),
446 rejected_via_triple: vec!(),
447 rejected_via_kind: vec!(),
448 should_match_name: true,
450 let library = match load_ctxt.maybe_load_library_crate() {
452 None if is_cross => {
453 // Try loading from target crates. This will abort later if we
454 // try to load a plugin registrar function,
456 should_link = info.should_link;
458 load_ctxt.target = &self.sess.target.target;
459 load_ctxt.triple = target_triple;
460 load_ctxt.filesearch = self.sess.target_filesearch(PathKind::Crate);
461 load_ctxt.load_library_crate()
463 None => { load_ctxt.report_load_errs(); unreachable!() },
466 let dylib = library.dylib.clone();
467 let register = should_link && self.existing_match(&info.name,
469 PathKind::Crate).is_none();
470 let metadata = if register {
471 // Register crate now to avoid double-reading metadata
472 let (_, cmd, _) = self.register_crate(&None, &info.ident,
473 &info.name, span, library,
475 PMDSource::Registered(cmd)
477 // Not registering the crate; just hold on to the metadata
478 PMDSource::Owned(library.metadata)
483 dylib: dylib.map(|p| p.0),
484 target_only: target_only,
488 /// Read exported macros.
489 pub fn read_exported_macros(&mut self, item: &ast::Item) -> Vec<ast::MacroDef> {
490 let ci = self.extract_crate_info(item).unwrap();
491 let ekrate = self.read_extension_crate(item.span, &ci);
493 let source_name = format!("<{} macros>", item.ident);
494 let mut macros = vec![];
495 decoder::each_exported_macro(ekrate.metadata.as_slice(),
497 |name, attrs, body| {
498 // NB: Don't use parse::parse_tts_from_source_str because it parses with
500 let mut p = parse::new_parser_from_source_str(&self.sess.parse_sess,
501 self.sess.opts.cfg.clone(),
505 let body = match p.parse_all_token_trees() {
512 let span = mk_sp(lo, p.last_span.hi);
514 // Mark the attrs as used
516 attr::mark_used(attr);
519 macros.push(ast::MacroDef {
520 ident: ast::Ident::with_empty_ctxt(name),
522 id: ast::DUMMY_NODE_ID,
524 imported_from: Some(item.ident),
525 // overridden in plugin/load.rs
528 allow_internal_unstable: false,
538 /// Look for a plugin registrar. Returns library path and symbol name.
539 pub fn find_plugin_registrar(&mut self, span: Span, name: &str)
540 -> Option<(PathBuf, String)> {
541 let ekrate = self.read_extension_crate(span, &CrateInfo {
542 name: name.to_string(),
543 ident: name.to_string(),
544 id: ast::DUMMY_NODE_ID,
548 if ekrate.target_only {
549 // Need to abort before syntax expansion.
550 let message = format!("plugin `{}` is not available for triple `{}` \
553 config::host_triple(),
554 self.sess.opts.target_triple);
555 span_fatal!(self.sess, span, E0456, "{}", &message[..]);
559 decoder::get_plugin_registrar_fn(ekrate.metadata.as_slice())
560 .map(|id| decoder::get_symbol_from_buf(ekrate.metadata.as_slice(), id));
562 match (ekrate.dylib.as_ref(), registrar) {
563 (Some(dylib), Some(reg)) => Some((dylib.to_path_buf(), reg)),
565 span_err!(self.sess, span, E0457,
566 "plugin `{}` only found in rlib format, but must be available \
569 // No need to abort because the loading code will just ignore this
577 fn register_statically_included_foreign_items(&mut self) {
578 let libs = self.cstore.get_used_libraries();
579 for (lib, list) in self.foreign_item_map.iter() {
580 let is_static = libs.borrow().iter().any(|&(ref name, kind)| {
581 lib == name && kind == cstore::NativeStatic
585 self.cstore.add_statically_included_foreign_item(*id);
591 fn inject_allocator_crate(&mut self) {
592 // Make sure that we actually need an allocator, if none of our
593 // dependencies need one then we definitely don't!
595 // Also, if one of our dependencies has an explicit allocator, then we
596 // also bail out as we don't need to implicitly inject one.
597 let mut needs_allocator = false;
598 let mut found_required_allocator = false;
599 self.cstore.iter_crate_data(|cnum, data| {
600 needs_allocator = needs_allocator || data.needs_allocator();
601 if data.is_allocator() {
602 debug!("{} required by rlib and is an allocator", data.name());
603 self.inject_allocator_dependency(cnum);
604 found_required_allocator = found_required_allocator ||
605 data.explicitly_linked.get();
608 if !needs_allocator || found_required_allocator { return }
610 // At this point we've determined that we need an allocator and no
611 // previous allocator has been activated. We look through our outputs of
612 // crate types to see what kind of allocator types we may need.
614 // The main special output type here is that rlibs do **not** need an
615 // allocator linked in (they're just object files), only final products
616 // (exes, dylibs, staticlibs) need allocators.
617 let mut need_lib_alloc = false;
618 let mut need_exe_alloc = false;
619 for ct in self.sess.crate_types.borrow().iter() {
621 config::CrateTypeExecutable => need_exe_alloc = true,
622 config::CrateTypeDylib |
623 config::CrateTypeStaticlib => need_lib_alloc = true,
624 config::CrateTypeRlib => {}
627 if !need_lib_alloc && !need_exe_alloc { return }
629 // The default allocator crate comes from the custom target spec, and we
630 // choose between the standard library allocator or exe allocator. This
631 // distinction exists because the default allocator for binaries (where
632 // the world is Rust) is different than library (where the world is
633 // likely *not* Rust).
635 // If a library is being produced, but we're also flagged with `-C
636 // prefer-dynamic`, then we interpret this as a *Rust* dynamic library
637 // is being produced so we use the exe allocator instead.
639 // What this boils down to is:
641 // * Binaries use jemalloc
642 // * Staticlibs and Rust dylibs use system malloc
643 // * Rust dylibs used as dependencies to rust use jemalloc
644 let name = if need_lib_alloc && !self.sess.opts.cg.prefer_dynamic {
645 &self.sess.target.target.options.lib_allocation_crate
647 &self.sess.target.target.options.exe_allocation_crate
649 let (cnum, data, _) = self.resolve_crate(&None, name, name, None,
651 PathKind::Crate, false);
653 // To ensure that the `-Z allocation-crate=foo` option isn't abused, and
654 // to ensure that the allocator is indeed an allocator, we verify that
655 // the crate loaded here is indeed tagged #![allocator].
656 if !data.is_allocator() {
657 self.sess.err(&format!("the allocator crate `{}` is not tagged \
658 with #![allocator]", data.name()));
661 self.sess.injected_allocator.set(Some(cnum));
662 self.inject_allocator_dependency(cnum);
665 fn inject_allocator_dependency(&self, allocator: ast::CrateNum) {
666 // Before we inject any dependencies, make sure we don't inject a
667 // circular dependency by validating that this allocator crate doesn't
668 // transitively depend on any `#![needs_allocator]` crates.
669 validate(self, allocator, allocator);
671 // All crates tagged with `needs_allocator` do not explicitly depend on
672 // the allocator selected for this compile, but in order for this
673 // compilation to be successfully linked we need to inject a dependency
674 // (to order the crates on the command line correctly).
676 // Here we inject a dependency from all crates with #![needs_allocator]
677 // to the crate tagged with #![allocator] for this compilation unit.
678 self.cstore.iter_crate_data(|cnum, data| {
679 if !data.needs_allocator() {
683 info!("injecting a dep from {} to {}", cnum, allocator);
684 let mut cnum_map = data.cnum_map.borrow_mut();
685 let remote_cnum = cnum_map.len() + 1;
686 let prev = cnum_map.insert(remote_cnum as ast::CrateNum, allocator);
687 assert!(prev.is_none());
690 fn validate(me: &CrateReader, krate: ast::CrateNum,
691 allocator: ast::CrateNum) {
692 let data = me.cstore.get_crate_data(krate);
693 if data.needs_allocator() {
694 let krate_name = data.name();
695 let data = me.cstore.get_crate_data(allocator);
696 let alloc_name = data.name();
697 me.sess.err(&format!("the allocator crate `{}` cannot depend \
698 on a crate that needs an allocator, but \
699 it depends on `{}`", alloc_name,
703 for (_, &dep) in data.cnum_map.borrow().iter() {
704 validate(me, dep, allocator);
710 impl<'a, 'b> LocalCrateReader<'a, 'b> {
711 pub fn new(sess: &'a Session, cstore: &'a CStore,
712 map: &'a hir_map::Map<'b>) -> LocalCrateReader<'a, 'b> {
716 creader: CrateReader::new(sess, cstore),
721 // Traverses an AST, reading all the information about use'd crates and
722 // extern libraries necessary for later resolving, typechecking, linking,
724 pub fn read_crates(&mut self, krate: &hir::Crate) {
725 self.process_crate(krate);
726 krate.visit_all_items(self);
727 self.creader.inject_allocator_crate();
729 if log_enabled!(log::INFO) {
730 dump_crates(&self.cstore);
733 for &(ref name, kind) in &self.sess.opts.libs {
734 register_native_lib(self.sess, self.cstore, None, name.clone(), kind);
736 self.creader.register_statically_included_foreign_items();
739 fn process_crate(&self, c: &hir::Crate) {
740 for a in c.attrs.iter().filter(|m| m.name() == "link_args") {
741 match a.value_str() {
742 Some(ref linkarg) => self.cstore.add_used_link_args(&linkarg),
743 None => { /* fallthrough */ }
748 fn process_item(&mut self, i: &hir::Item) {
750 hir::ItemExternCrate(_) => {
751 if !should_link_hir(i) {
755 match self.creader.extract_crate_info_hir(i) {
757 let (cnum, cmeta, _) = self.creader.resolve_crate(&None,
764 let def_id = self.ast_map.local_def_id(i.id);
765 let def_path = self.ast_map.def_path(def_id);
766 cmeta.update_local_def_path(def_path);
767 self.ast_map.with_path(i.id, |path| {
768 cmeta.update_local_path(path)
770 self.cstore.add_extern_mod_stmt_cnum(info.id, cnum);
775 hir::ItemForeignMod(ref fm) => self.process_foreign_mod(i, fm),
780 fn process_foreign_mod(&mut self, i: &hir::Item, fm: &hir::ForeignMod) {
781 if fm.abi == abi::Rust || fm.abi == abi::RustIntrinsic || fm.abi == abi::PlatformIntrinsic {
785 // First, add all of the custom #[link_args] attributes
786 for m in i.attrs.iter().filter(|a| a.check_name("link_args")) {
787 if let Some(linkarg) = m.value_str() {
788 self.cstore.add_used_link_args(&linkarg);
792 // Next, process all of the #[link(..)]-style arguments
793 for m in i.attrs.iter().filter(|a| a.check_name("link")) {
794 let items = match m.meta_item_list() {
798 let kind = items.iter().find(|k| {
800 }).and_then(|a| a.value_str());
801 let kind = match kind.as_ref().map(|s| &s[..]) {
802 Some("static") => cstore::NativeStatic,
803 Some("dylib") => cstore::NativeUnknown,
804 Some("framework") => cstore::NativeFramework,
806 span_err!(self.sess, m.span, E0458,
807 "unknown kind: `{}`", k);
808 cstore::NativeUnknown
810 None => cstore::NativeUnknown
812 let n = items.iter().find(|n| {
814 }).and_then(|a| a.value_str());
818 span_err!(self.sess, m.span, E0459,
819 "#[link(...)] specified without `name = \"foo\"`");
820 InternedString::new("foo")
823 register_native_lib(self.sess, self.cstore, Some(m.span), n.to_string(), kind);
826 // Finally, process the #[linked_from = "..."] attribute
827 for m in i.attrs.iter().filter(|a| a.check_name("linked_from")) {
828 let lib_name = match m.value_str() {
832 let list = self.creader.foreign_item_map.entry(lib_name.to_string())
833 .or_insert(Vec::new());
834 list.extend(fm.items.iter().map(|it| it.id));
839 /// Imports the codemap from an external crate into the codemap of the crate
840 /// currently being compiled (the "local crate").
842 /// The import algorithm works analogous to how AST items are inlined from an
843 /// external crate's metadata:
844 /// For every FileMap in the external codemap an 'inline' copy is created in the
845 /// local codemap. The correspondence relation between external and local
846 /// FileMaps is recorded in the `ImportedFileMap` objects returned from this
847 /// function. When an item from an external crate is later inlined into this
848 /// crate, this correspondence information is used to translate the span
849 /// information of the inlined item so that it refers the correct positions in
850 /// the local codemap (see `astencode::DecodeContext::tr_span()`).
852 /// The import algorithm in the function below will reuse FileMaps already
853 /// existing in the local codemap. For example, even if the FileMap of some
854 /// source file of libstd gets imported many times, there will only ever be
855 /// one FileMap object for the corresponding file in the local codemap.
857 /// Note that imported FileMaps do not actually contain the source code of the
858 /// file they represent, just information about length, line breaks, and
859 /// multibyte characters. This information is enough to generate valid debuginfo
860 /// for items inlined from other crates.
861 pub fn import_codemap(local_codemap: &codemap::CodeMap,
862 metadata: &MetadataBlob)
863 -> Vec<cstore::ImportedFileMap> {
864 let external_codemap = decoder::get_imported_filemaps(metadata.as_slice());
866 let imported_filemaps = external_codemap.into_iter().map(|filemap_to_import| {
867 // Try to find an existing FileMap that can be reused for the filemap to
868 // be imported. A FileMap is reusable if it is exactly the same, just
869 // positioned at a different offset within the codemap.
870 let reusable_filemap = {
874 .find(|fm| are_equal_modulo_startpos(&fm, &filemap_to_import))
875 .map(|rc| rc.clone())
878 match reusable_filemap {
880 cstore::ImportedFileMap {
881 original_start_pos: filemap_to_import.start_pos,
882 original_end_pos: filemap_to_import.end_pos,
883 translated_filemap: fm
887 // We can't reuse an existing FileMap, so allocate a new one
888 // containing the information we need.
889 let codemap::FileMap {
896 } = filemap_to_import;
898 let source_length = (end_pos - start_pos).to_usize();
900 // Translate line-start positions and multibyte character
901 // position into frame of reference local to file.
902 // `CodeMap::new_imported_filemap()` will then translate those
903 // coordinates to their new global frame of reference when the
904 // offset of the FileMap is known.
905 let mut lines = lines.into_inner();
906 for pos in &mut lines {
907 *pos = *pos - start_pos;
909 let mut multibyte_chars = multibyte_chars.into_inner();
910 for mbc in &mut multibyte_chars {
911 mbc.pos = mbc.pos - start_pos;
914 let local_version = local_codemap.new_imported_filemap(name,
918 cstore::ImportedFileMap {
919 original_start_pos: start_pos,
920 original_end_pos: end_pos,
921 translated_filemap: local_version
927 return imported_filemaps;
929 fn are_equal_modulo_startpos(fm1: &codemap::FileMap,
930 fm2: &codemap::FileMap)
932 if fm1.name != fm2.name {
936 let lines1 = fm1.lines.borrow();
937 let lines2 = fm2.lines.borrow();
939 if lines1.len() != lines2.len() {
943 for (&line1, &line2) in lines1.iter().zip(lines2.iter()) {
944 if (line1 - fm1.start_pos) != (line2 - fm2.start_pos) {
949 let multibytes1 = fm1.multibyte_chars.borrow();
950 let multibytes2 = fm2.multibyte_chars.borrow();
952 if multibytes1.len() != multibytes2.len() {
956 for (mb1, mb2) in multibytes1.iter().zip(multibytes2.iter()) {
957 if (mb1.bytes != mb2.bytes) ||
958 ((mb1.pos - fm1.start_pos) != (mb2.pos - fm2.start_pos)) {