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
16 use session::{config, Session};
17 use session::search_paths::PathKind;
18 use metadata::common::rustc_version;
20 use metadata::cstore::{CStore, CrateSource, MetadataBlob};
21 use metadata::decoder;
23 use metadata::loader::CratePaths;
24 use util::nodemap::FnvHashMap;
25 use 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::parse::token::InternedString;
39 use syntax::util::small_vector::SmallVector;
40 use rustc_front::visit;
44 pub struct LocalCrateReader<'a, 'b:'a> {
46 creader: CrateReader<'a>,
47 ast_map: &'a hir_map::Map<'b>,
50 pub struct CrateReader<'a> {
52 next_crate_num: ast::CrateNum,
53 foreign_item_map: FnvHashMap<String, Vec<ast::NodeId>>,
56 impl<'a, 'b, 'v> visit::Visitor<'v> for LocalCrateReader<'a, 'b> {
57 fn visit_item(&mut self, a: &hir::Item) {
59 visit::walk_item(self, a);
63 fn dump_crates(cstore: &CStore) {
64 info!("resolved crates:");
65 cstore.iter_crate_data_origins(|_, data, opt_source| {
66 info!(" name: {}", data.name());
67 info!(" cnum: {}", data.cnum);
68 info!(" hash: {}", data.hash());
69 info!(" reqd: {}", data.explicitly_linked.get());
71 let CrateSource { dylib, rlib, cnum: _ } = cs;
72 dylib.map(|dl| info!(" dylib: {}", dl.0.display()));
73 rlib.map(|rl| info!(" rlib: {}", rl.0.display()));
78 fn should_link(i: &ast::Item) -> bool {
79 !attr::contains_name(&i.attrs, "no_link")
82 fn should_link_hir(i: &hir::Item) -> bool {
83 !attr::contains_name(&i.attrs, "no_link")
93 pub fn validate_crate_name(sess: Option<&Session>, s: &str, sp: Option<Span>) {
96 (_, None) => panic!("{}", s),
97 (Some(sp), Some(sess)) => sess.span_err(sp, s),
98 (None, Some(sess)) => sess.err(s),
102 say("crate name must not be empty");
105 if c.is_alphanumeric() { continue }
106 if c == '_' { continue }
107 say(&format!("invalid character `{}` in crate name: `{}`", c, s));
110 Some(sess) => sess.abort_if_errors(),
116 fn register_native_lib(sess: &Session,
119 kind: cstore::NativeLibraryKind) {
123 span_err!(sess, span, E0454,
124 "#[link(name = \"\")] given with empty name");
127 sess.err("empty library name given via `-l`");
132 let is_osx = sess.target.target.options.is_like_osx;
133 if kind == cstore::NativeFramework && !is_osx {
134 let msg = "native frameworks are only available on OSX targets";
137 span_err!(sess, span, E0455,
140 None => sess.err(msg),
143 sess.cstore.add_used_library(name, kind);
146 // Extra info about a crate loaded for plugins or exported macros.
147 struct ExtensionCrate {
149 dylib: Option<PathBuf>,
154 Registered(Rc<cstore::crate_metadata>),
159 pub fn as_slice<'a>(&'a self) -> &'a [u8] {
161 PMDSource::Registered(ref cmd) => cmd.data(),
162 PMDSource::Owned(ref mdb) => mdb.as_slice(),
167 impl<'a> CrateReader<'a> {
168 pub fn new(sess: &'a Session) -> CrateReader<'a> {
171 next_crate_num: sess.cstore.next_crate_num(),
172 foreign_item_map: FnvHashMap(),
176 fn extract_crate_info(&self, i: &ast::Item) -> Option<CrateInfo> {
178 ast::ItemExternCrate(ref path_opt) => {
179 debug!("resolving extern crate stmt. ident: {} path_opt: {:?}",
181 let name = match *path_opt {
183 validate_crate_name(Some(self.sess), &name.as_str(),
187 None => i.ident.to_string(),
190 ident: i.ident.to_string(),
193 should_link: should_link(i),
200 // Dup of the above, but for the hir
201 fn extract_crate_info_hir(&self, i: &hir::Item) -> Option<CrateInfo> {
203 hir::ItemExternCrate(ref path_opt) => {
204 debug!("resolving extern crate stmt. ident: {} path_opt: {:?}",
206 let name = match *path_opt {
208 validate_crate_name(Some(self.sess), &name.as_str(),
212 None => i.name.to_string(),
215 ident: i.name.to_string(),
218 should_link: should_link_hir(i),
225 fn existing_match(&self, name: &str, hash: Option<&Svh>, kind: PathKind)
226 -> Option<ast::CrateNum> {
228 self.sess.cstore.iter_crate_data(|cnum, data| {
229 if data.name != name { return }
232 Some(hash) if *hash == data.hash() => { ret = Some(cnum); return }
237 // When the hash is None we're dealing with a top-level dependency
238 // in which case we may have a specification on the command line for
239 // this library. Even though an upstream library may have loaded
240 // something of the same name, we have to make sure it was loaded
241 // from the exact same location as well.
243 // We're also sure to compare *paths*, not actual byte slices. The
244 // `source` stores paths which are normalized which may be different
245 // from the strings on the command line.
246 let source = self.sess.cstore.get_used_crate_source(cnum).unwrap();
247 if let Some(locs) = self.sess.opts.externs.get(name) {
248 let found = locs.iter().any(|l| {
249 let l = fs::canonicalize(l).ok();
250 source.dylib.as_ref().map(|p| &p.0) == l.as_ref() ||
251 source.rlib.as_ref().map(|p| &p.0) == l.as_ref()
259 // Alright, so we've gotten this far which means that `data` has the
260 // right name, we don't have a hash, and we don't have a --extern
261 // pointing for ourselves. We're still not quite yet done because we
262 // have to make sure that this crate was found in the crate lookup
263 // path (this is a top-level dependency) as we don't want to
264 // implicitly load anything inside the dependency lookup path.
265 let prev_kind = source.dylib.as_ref().or(source.rlib.as_ref())
267 if ret.is_none() && (prev_kind == kind || prev_kind == PathKind::All) {
274 fn verify_rustc_version(&self,
277 metadata: &MetadataBlob) {
278 let crate_rustc_version = decoder::crate_rustc_version(metadata.as_slice());
279 if crate_rustc_version != Some(rustc_version()) {
280 span_err!(self.sess, span, E0514,
281 "the crate `{}` has been compiled with {}, which is \
282 incompatible with this version of rustc",
285 .as_ref().map(|s|&**s)
286 .unwrap_or("an old version of rustc")
288 self.sess.abort_if_errors();
292 fn register_crate(&mut self,
293 root: &Option<CratePaths>,
297 lib: loader::Library,
298 explicitly_linked: bool)
299 -> (ast::CrateNum, Rc<cstore::crate_metadata>,
300 cstore::CrateSource) {
301 self.verify_rustc_version(name, span, &lib.metadata);
303 // Claim this crate number and cache it
304 let cnum = self.next_crate_num;
305 self.next_crate_num += 1;
307 // Stash paths for top-most crate locally if necessary.
308 let crate_paths = if root.is_none() {
310 ident: ident.to_string(),
311 dylib: lib.dylib.clone().map(|p| p.0),
312 rlib: lib.rlib.clone().map(|p| p.0),
317 // Maintain a reference to the top most crate.
318 let root = if root.is_some() { root } else { &crate_paths };
320 let loader::Library { dylib, rlib, metadata } = lib;
322 let cnum_map = self.resolve_crate_deps(root, metadata.as_slice(), span);
323 let staged_api = self.is_staged_api(metadata.as_slice());
325 let cmeta = Rc::new(cstore::crate_metadata {
326 name: name.to_string(),
327 local_path: RefCell::new(SmallVector::zero()),
328 local_def_path: RefCell::new(vec![]),
329 index: decoder::load_index(metadata.as_slice()),
330 xref_index: decoder::load_xrefs(metadata.as_slice()),
332 cnum_map: RefCell::new(cnum_map),
334 codemap_import_info: RefCell::new(vec![]),
336 staged_api: staged_api,
337 explicitly_linked: Cell::new(explicitly_linked),
340 let source = cstore::CrateSource {
346 self.sess.cstore.set_crate_data(cnum, cmeta.clone());
347 self.sess.cstore.add_used_crate_source(source.clone());
348 (cnum, cmeta, source)
351 fn is_staged_api(&self, data: &[u8]) -> bool {
352 let attrs = decoder::get_crate_attributes(data);
354 if &attr.name()[..] == "staged_api" {
355 match attr.node.value.node { ast::MetaWord(_) => return true, _ => (/*pass*/) }
362 fn resolve_crate(&mut self,
363 root: &Option<CratePaths>,
369 explicitly_linked: bool)
370 -> (ast::CrateNum, Rc<cstore::crate_metadata>,
371 cstore::CrateSource) {
372 match self.existing_match(name, hash, kind) {
374 let mut load_ctxt = loader::Context {
379 hash: hash.map(|a| &*a),
380 filesearch: self.sess.target_filesearch(kind),
381 target: &self.sess.target.target,
382 triple: &self.sess.opts.target_triple,
384 rejected_via_hash: vec!(),
385 rejected_via_triple: vec!(),
386 rejected_via_kind: vec!(),
387 should_match_name: true,
389 let library = load_ctxt.load_library_crate();
390 self.register_crate(root, ident, name, span, library,
394 let data = self.sess.cstore.get_crate_data(cnum);
395 if explicitly_linked && !data.explicitly_linked.get() {
396 data.explicitly_linked.set(explicitly_linked);
398 (cnum, data, self.sess.cstore.get_used_crate_source(cnum).unwrap())
403 // Go through the crate metadata and load any crates that it references
404 fn resolve_crate_deps(&mut self,
405 root: &Option<CratePaths>,
406 cdata: &[u8], span : Span)
407 -> cstore::cnum_map {
408 debug!("resolving deps of external crate");
409 // The map from crate numbers in the crate we're resolving to local crate
411 decoder::get_crate_deps(cdata).iter().map(|dep| {
412 debug!("resolving dep crate {} hash: `{}`", dep.name, dep.hash);
413 let (local_cnum, _, _) = self.resolve_crate(root,
418 PathKind::Dependency,
419 dep.explicitly_linked);
420 (dep.cnum, local_cnum)
424 fn read_extension_crate(&mut self, span: Span, info: &CrateInfo) -> ExtensionCrate {
425 let target_triple = &self.sess.opts.target_triple[..];
426 let is_cross = target_triple != config::host_triple();
427 let mut should_link = info.should_link && !is_cross;
428 let mut target_only = false;
429 let ident = info.ident.clone();
430 let name = info.name.clone();
431 let mut load_ctxt = loader::Context {
435 crate_name: &name[..],
437 filesearch: self.sess.host_filesearch(PathKind::Crate),
438 target: &self.sess.host,
439 triple: config::host_triple(),
441 rejected_via_hash: vec!(),
442 rejected_via_triple: vec!(),
443 rejected_via_kind: vec!(),
444 should_match_name: true,
446 let library = match load_ctxt.maybe_load_library_crate() {
448 None if is_cross => {
449 // Try loading from target crates. This will abort later if we
450 // try to load a plugin registrar function,
452 should_link = info.should_link;
454 load_ctxt.target = &self.sess.target.target;
455 load_ctxt.triple = target_triple;
456 load_ctxt.filesearch = self.sess.target_filesearch(PathKind::Crate);
457 load_ctxt.load_library_crate()
459 None => { load_ctxt.report_load_errs(); unreachable!() },
462 let dylib = library.dylib.clone();
463 let register = should_link && self.existing_match(&info.name,
465 PathKind::Crate).is_none();
466 let metadata = if register {
467 // Register crate now to avoid double-reading metadata
468 let (_, cmd, _) = self.register_crate(&None, &info.ident,
469 &info.name, span, library,
471 PMDSource::Registered(cmd)
473 // Not registering the crate; just hold on to the metadata
474 PMDSource::Owned(library.metadata)
479 dylib: dylib.map(|p| p.0),
480 target_only: target_only,
484 /// Read exported macros.
485 pub fn read_exported_macros(&mut self, item: &ast::Item) -> Vec<ast::MacroDef> {
486 let ci = self.extract_crate_info(item).unwrap();
487 let ekrate = self.read_extension_crate(item.span, &ci);
489 let source_name = format!("<{} macros>", item.ident);
490 let mut macros = vec![];
491 decoder::each_exported_macro(ekrate.metadata.as_slice(),
492 &*self.sess.cstore.intr,
493 |name, attrs, body| {
494 // NB: Don't use parse::parse_tts_from_source_str because it parses with
496 let mut p = parse::new_parser_from_source_str(&self.sess.parse_sess,
497 self.sess.opts.cfg.clone(),
501 let body = match p.parse_all_token_trees() {
503 Err(err) => panic!(err),
505 let span = mk_sp(lo, p.last_span.hi);
508 // Mark the attrs as used
510 attr::mark_used(attr);
513 macros.push(ast::MacroDef {
514 ident: ast::Ident::with_empty_ctxt(name),
516 id: ast::DUMMY_NODE_ID,
518 imported_from: Some(item.ident),
519 // overridden in plugin/load.rs
522 allow_internal_unstable: false,
532 /// Look for a plugin registrar. Returns library path and symbol name.
533 pub fn find_plugin_registrar(&mut self, span: Span, name: &str)
534 -> Option<(PathBuf, String)> {
535 let ekrate = self.read_extension_crate(span, &CrateInfo {
536 name: name.to_string(),
537 ident: name.to_string(),
538 id: ast::DUMMY_NODE_ID,
542 if ekrate.target_only {
543 // Need to abort before syntax expansion.
544 let message = format!("plugin `{}` is not available for triple `{}` \
547 config::host_triple(),
548 self.sess.opts.target_triple);
549 span_err!(self.sess, span, E0456, "{}", &message[..]);
550 self.sess.abort_if_errors();
554 decoder::get_plugin_registrar_fn(ekrate.metadata.as_slice())
555 .map(|id| decoder::get_symbol_from_buf(ekrate.metadata.as_slice(), id));
557 match (ekrate.dylib.as_ref(), registrar) {
558 (Some(dylib), Some(reg)) => Some((dylib.to_path_buf(), reg)),
560 span_err!(self.sess, span, E0457,
561 "plugin `{}` only found in rlib format, but must be available \
564 // No need to abort because the loading code will just ignore this
572 fn register_statically_included_foreign_items(&mut self) {
573 let libs = self.sess.cstore.get_used_libraries();
574 for (lib, list) in self.foreign_item_map.iter() {
575 let is_static = libs.borrow().iter().any(|&(ref name, kind)| {
576 lib == name && kind == cstore::NativeStatic
580 self.sess.cstore.add_statically_included_foreign_item(*id);
586 fn inject_allocator_crate(&mut self) {
587 // Make sure that we actually need an allocator, if none of our
588 // dependencies need one then we definitely don't!
590 // Also, if one of our dependencies has an explicit allocator, then we
591 // also bail out as we don't need to implicitly inject one.
592 let mut needs_allocator = false;
593 let mut found_required_allocator = false;
594 self.sess.cstore.iter_crate_data(|cnum, data| {
595 needs_allocator = needs_allocator || data.needs_allocator();
596 if data.is_allocator() {
597 debug!("{} required by rlib and is an allocator", data.name());
598 self.inject_allocator_dependency(cnum);
599 found_required_allocator = found_required_allocator ||
600 data.explicitly_linked.get();
603 if !needs_allocator || found_required_allocator { return }
605 // At this point we've determined that we need an allocator and no
606 // previous allocator has been activated. We look through our outputs of
607 // crate types to see what kind of allocator types we may need.
609 // The main special output type here is that rlibs do **not** need an
610 // allocator linked in (they're just object files), only final products
611 // (exes, dylibs, staticlibs) need allocators.
612 let mut need_lib_alloc = false;
613 let mut need_exe_alloc = false;
614 for ct in self.sess.crate_types.borrow().iter() {
616 config::CrateTypeExecutable => need_exe_alloc = true,
617 config::CrateTypeDylib |
618 config::CrateTypeStaticlib => need_lib_alloc = true,
619 config::CrateTypeRlib => {}
622 if !need_lib_alloc && !need_exe_alloc { return }
624 // The default allocator crate comes from the custom target spec, and we
625 // choose between the standard library allocator or exe allocator. This
626 // distinction exists because the default allocator for binaries (where
627 // the world is Rust) is different than library (where the world is
628 // likely *not* Rust).
630 // If a library is being produced, but we're also flagged with `-C
631 // prefer-dynamic`, then we interpret this as a *Rust* dynamic library
632 // is being produced so we use the exe allocator instead.
634 // What this boils down to is:
636 // * Binaries use jemalloc
637 // * Staticlibs and Rust dylibs use system malloc
638 // * Rust dylibs used as dependencies to rust use jemalloc
639 let name = if need_lib_alloc && !self.sess.opts.cg.prefer_dynamic {
640 &self.sess.target.target.options.lib_allocation_crate
642 &self.sess.target.target.options.exe_allocation_crate
644 let (cnum, data, _) = self.resolve_crate(&None, name, name, None,
646 PathKind::Crate, false);
648 // To ensure that the `-Z allocation-crate=foo` option isn't abused, and
649 // to ensure that the allocator is indeed an allocator, we verify that
650 // the crate loaded here is indeed tagged #![allocator].
651 if !data.is_allocator() {
652 self.sess.err(&format!("the allocator crate `{}` is not tagged \
653 with #![allocator]", data.name()));
656 self.sess.injected_allocator.set(Some(cnum));
657 self.inject_allocator_dependency(cnum);
660 fn inject_allocator_dependency(&self, allocator: ast::CrateNum) {
661 // Before we inject any dependencies, make sure we don't inject a
662 // circular dependency by validating that this allocator crate doesn't
663 // transitively depend on any `#![needs_allocator]` crates.
664 validate(self, allocator, allocator);
666 // All crates tagged with `needs_allocator` do not explicitly depend on
667 // the allocator selected for this compile, but in order for this
668 // compilation to be successfully linked we need to inject a dependency
669 // (to order the crates on the command line correctly).
671 // Here we inject a dependency from all crates with #![needs_allocator]
672 // to the crate tagged with #![allocator] for this compilation unit.
673 self.sess.cstore.iter_crate_data(|cnum, data| {
674 if !data.needs_allocator() {
678 info!("injecting a dep from {} to {}", cnum, allocator);
679 let mut cnum_map = data.cnum_map.borrow_mut();
680 let remote_cnum = cnum_map.len() + 1;
681 let prev = cnum_map.insert(remote_cnum as ast::CrateNum, allocator);
682 assert!(prev.is_none());
685 fn validate(me: &CrateReader, krate: ast::CrateNum,
686 allocator: ast::CrateNum) {
687 let data = me.sess.cstore.get_crate_data(krate);
688 if data.needs_allocator() {
689 let krate_name = data.name();
690 let data = me.sess.cstore.get_crate_data(allocator);
691 let alloc_name = data.name();
692 me.sess.err(&format!("the allocator crate `{}` cannot depend \
693 on a crate that needs an allocator, but \
694 it depends on `{}`", alloc_name,
698 for (_, &dep) in data.cnum_map.borrow().iter() {
699 validate(me, dep, allocator);
705 impl<'a, 'b> LocalCrateReader<'a, 'b> {
706 pub fn new(sess: &'a Session, map: &'a hir_map::Map<'b>) -> LocalCrateReader<'a, 'b> {
709 creader: CrateReader::new(sess),
714 // Traverses an AST, reading all the information about use'd crates and
715 // extern libraries necessary for later resolving, typechecking, linking,
717 pub fn read_crates(&mut self, krate: &hir::Crate) {
718 self.process_crate(krate);
719 visit::walk_crate(self, krate);
720 self.creader.inject_allocator_crate();
722 if log_enabled!(log::INFO) {
723 dump_crates(&self.sess.cstore);
726 for &(ref name, kind) in &self.sess.opts.libs {
727 register_native_lib(self.sess, None, name.clone(), kind);
729 self.creader.register_statically_included_foreign_items();
732 fn process_crate(&self, c: &hir::Crate) {
733 for a in c.attrs.iter().filter(|m| m.name() == "link_args") {
734 match a.value_str() {
735 Some(ref linkarg) => self.sess.cstore.add_used_link_args(&linkarg),
736 None => { /* fallthrough */ }
741 fn process_item(&mut self, i: &hir::Item) {
743 hir::ItemExternCrate(_) => {
744 if !should_link_hir(i) {
748 match self.creader.extract_crate_info_hir(i) {
750 let (cnum, cmeta, _) = self.creader.resolve_crate(&None,
757 let def_id = self.ast_map.local_def_id(i.id);
758 let def_path = self.ast_map.def_path(def_id);
759 cmeta.update_local_def_path(def_path);
760 self.ast_map.with_path(i.id, |path| {
761 cmeta.update_local_path(path)
763 self.sess.cstore.add_extern_mod_stmt_cnum(info.id, cnum);
768 hir::ItemForeignMod(ref fm) => self.process_foreign_mod(i, fm),
773 fn process_foreign_mod(&mut self, i: &hir::Item, fm: &hir::ForeignMod) {
774 if fm.abi == abi::Rust || fm.abi == abi::RustIntrinsic || fm.abi == abi::PlatformIntrinsic {
778 // First, add all of the custom #[link_args] attributes
779 for m in i.attrs.iter().filter(|a| a.check_name("link_args")) {
780 if let Some(linkarg) = m.value_str() {
781 self.sess.cstore.add_used_link_args(&linkarg);
785 // Next, process all of the #[link(..)]-style arguments
786 for m in i.attrs.iter().filter(|a| a.check_name("link")) {
787 let items = match m.meta_item_list() {
791 let kind = items.iter().find(|k| {
793 }).and_then(|a| a.value_str());
794 let kind = match kind.as_ref().map(|s| &s[..]) {
795 Some("static") => cstore::NativeStatic,
796 Some("dylib") => cstore::NativeUnknown,
797 Some("framework") => cstore::NativeFramework,
799 span_err!(self.sess, m.span, E0458,
800 "unknown kind: `{}`", k);
801 cstore::NativeUnknown
803 None => cstore::NativeUnknown
805 let n = items.iter().find(|n| {
807 }).and_then(|a| a.value_str());
811 span_err!(self.sess, m.span, E0459,
812 "#[link(...)] specified without `name = \"foo\"`");
813 InternedString::new("foo")
816 register_native_lib(self.sess, Some(m.span), n.to_string(), kind);
819 // Finally, process the #[linked_from = "..."] attribute
820 for m in i.attrs.iter().filter(|a| a.check_name("linked_from")) {
821 let lib_name = match m.value_str() {
825 let list = self.creader.foreign_item_map.entry(lib_name.to_string())
826 .or_insert(Vec::new());
827 list.extend(fm.items.iter().map(|it| it.id));
832 /// Imports the codemap from an external crate into the codemap of the crate
833 /// currently being compiled (the "local crate").
835 /// The import algorithm works analogous to how AST items are inlined from an
836 /// external crate's metadata:
837 /// For every FileMap in the external codemap an 'inline' copy is created in the
838 /// local codemap. The correspondence relation between external and local
839 /// FileMaps is recorded in the `ImportedFileMap` objects returned from this
840 /// function. When an item from an external crate is later inlined into this
841 /// crate, this correspondence information is used to translate the span
842 /// information of the inlined item so that it refers the correct positions in
843 /// the local codemap (see `astencode::DecodeContext::tr_span()`).
845 /// The import algorithm in the function below will reuse FileMaps already
846 /// existing in the local codemap. For example, even if the FileMap of some
847 /// source file of libstd gets imported many times, there will only ever be
848 /// one FileMap object for the corresponding file in the local codemap.
850 /// Note that imported FileMaps do not actually contain the source code of the
851 /// file they represent, just information about length, line breaks, and
852 /// multibyte characters. This information is enough to generate valid debuginfo
853 /// for items inlined from other crates.
854 pub fn import_codemap(local_codemap: &codemap::CodeMap,
855 metadata: &MetadataBlob)
856 -> Vec<cstore::ImportedFileMap> {
857 let external_codemap = decoder::get_imported_filemaps(metadata.as_slice());
859 let imported_filemaps = external_codemap.into_iter().map(|filemap_to_import| {
860 // Try to find an existing FileMap that can be reused for the filemap to
861 // be imported. A FileMap is reusable if it is exactly the same, just
862 // positioned at a different offset within the codemap.
863 let reusable_filemap = {
867 .find(|fm| are_equal_modulo_startpos(&fm, &filemap_to_import))
868 .map(|rc| rc.clone())
871 match reusable_filemap {
873 cstore::ImportedFileMap {
874 original_start_pos: filemap_to_import.start_pos,
875 original_end_pos: filemap_to_import.end_pos,
876 translated_filemap: fm
880 // We can't reuse an existing FileMap, so allocate a new one
881 // containing the information we need.
882 let codemap::FileMap {
889 } = filemap_to_import;
891 let source_length = (end_pos - start_pos).to_usize();
893 // Translate line-start positions and multibyte character
894 // position into frame of reference local to file.
895 // `CodeMap::new_imported_filemap()` will then translate those
896 // coordinates to their new global frame of reference when the
897 // offset of the FileMap is known.
898 let mut lines = lines.into_inner();
899 for pos in &mut lines {
900 *pos = *pos - start_pos;
902 let mut multibyte_chars = multibyte_chars.into_inner();
903 for mbc in &mut multibyte_chars {
904 mbc.pos = mbc.pos - start_pos;
907 let local_version = local_codemap.new_imported_filemap(name,
911 cstore::ImportedFileMap {
912 original_start_pos: start_pos,
913 original_end_pos: end_pos,
914 translated_filemap: local_version
920 return imported_filemaps;
922 fn are_equal_modulo_startpos(fm1: &codemap::FileMap,
923 fm2: &codemap::FileMap)
925 if fm1.name != fm2.name {
929 let lines1 = fm1.lines.borrow();
930 let lines2 = fm2.lines.borrow();
932 if lines1.len() != lines2.len() {
936 for (&line1, &line2) in lines1.iter().zip(lines2.iter()) {
937 if (line1 - fm1.start_pos) != (line2 - fm2.start_pos) {
942 let multibytes1 = fm1.multibyte_chars.borrow();
943 let multibytes2 = fm2.multibyte_chars.borrow();
945 if multibytes1.len() != multibytes2.len() {
949 for (mb1, mb2) in multibytes1.iter().zip(multibytes2.iter()) {
950 if (mb1.bytes != mb2.bytes) ||
951 ((mb1.pos - fm1.start_pos) != (mb2.pos - fm2.start_pos)) {