src/librustc_metadata/creader.rs

   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.
   4 //
   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.
  10
  11 //! Validates all used crates and extern libraries and loads their metadata
  12
  13 use cstore::{self, CStore, CrateSource, MetadataBlob};
  14 use locator::{self, CratePaths};
  15 use schema::CrateRoot;
  16
  17 use rustc::hir::def_id::{CrateNum, DefIndex};
  18 use rustc::hir::svh::Svh;
  19 use rustc::middle::cstore::LoadedMacros;
  20 use rustc::session::{config, Session};
  21 use rustc_back::PanicStrategy;
  22 use rustc::session::search_paths::PathKind;
  23 use rustc::middle;
  24 use rustc::middle::cstore::{CrateStore, validate_crate_name, ExternCrate};
  25 use rustc::util::nodemap::{FnvHashMap, FnvHashSet};
  26 use rustc::hir::map::Definitions;
  27
  28 use std::cell::{RefCell, Cell};
  29 use std::ops::Deref;
  30 use std::path::PathBuf;
  31 use std::rc::Rc;
  32 use std::fs;
  33
  34 use syntax::ast;
  35 use syntax::abi::Abi;
  36 use syntax::parse;
  37 use syntax::attr;
  38 use syntax::ext::base::SyntaxExtension;
  39 use syntax::parse::token::{InternedString, intern};
  40 use syntax_pos::{self, Span, mk_sp};
  41 use log;
  42
  43 pub struct Library {
  44     pub dylib: Option<(PathBuf, PathKind)>,
  45     pub rlib: Option<(PathBuf, PathKind)>,
  46     pub metadata: MetadataBlob,
  47 }
  48
  49 pub struct CrateLoader<'a> {
  50     pub sess: &'a Session,
  51     cstore: &'a CStore,
  52     next_crate_num: CrateNum,
  53     foreign_item_map: FnvHashMap<String, Vec<ast::NodeId>>,
  54     local_crate_name: String,
  55 }
  56
  57 fn dump_crates(cstore: &CStore) {
  58     info!("resolved crates:");
  59     cstore.iter_crate_data_origins(|_, data, opt_source| {
  60         info!("  name: {}", data.name());
  61         info!("  cnum: {}", data.cnum);
  62         info!("  hash: {}", data.hash());
  63         info!("  reqd: {}", data.explicitly_linked.get());
  64         opt_source.map(|cs| {
  65             let CrateSource { dylib, rlib, cnum: _ } = cs;
  66             dylib.map(|dl| info!("  dylib: {}", dl.0.display()));
  67             rlib.map(|rl|  info!("   rlib: {}", rl.0.display()));
  68         });
  69     })
  70 }
  71
  72 fn should_link(i: &ast::Item) -> bool {
  73     !attr::contains_name(&i.attrs, "no_link")
  74 }
  75
  76 #[derive(Debug)]
  77 struct ExternCrateInfo {
  78     ident: String,
  79     name: String,
  80     id: ast::NodeId,
  81     should_link: bool,
  82 }
  83
  84 fn register_native_lib(sess: &Session,
  85                        cstore: &CStore,
  86                        span: Option<Span>,
  87                        name: String,
  88                        kind: cstore::NativeLibraryKind) {
  89     if name.is_empty() {
  90         match span {
  91             Some(span) => {
  92                 struct_span_err!(sess, span, E0454,
  93                                  "#[link(name = \"\")] given with empty name")
  94                     .span_label(span, &format!("empty name given"))
  95                     .emit();
  96             }
  97             None => {
  98                 sess.err("empty library name given via `-l`");
  99             }
 100         }
 101         return
 102     }
 103     let is_osx = sess.target.target.options.is_like_osx;
 104     if kind == cstore::NativeFramework && !is_osx {
 105         let msg = "native frameworks are only available on OSX targets";
 106         match span {
 107             Some(span) => {
 108                 span_err!(sess, span, E0455,
 109                           "{}", msg)
 110             }
 111             None => sess.err(msg),
 112         }
 113     }
 114     cstore.add_used_library(name, kind);
 115 }
 116
 117 // Extra info about a crate loaded for plugins or exported macros.
 118 struct ExtensionCrate {
 119     metadata: PMDSource,
 120     dylib: Option<PathBuf>,
 121     target_only: bool,
 122 }
 123
 124 enum PMDSource {
 125     Registered(Rc<cstore::CrateMetadata>),
 126     Owned(Library),
 127 }
 128
 129 impl Deref for PMDSource {
 130     type Target = MetadataBlob;
 131
 132     fn deref(&self) -> &MetadataBlob {
 133         match *self {
 134             PMDSource::Registered(ref cmd) => &cmd.blob,
 135             PMDSource::Owned(ref lib) => &lib.metadata
 136         }
 137     }
 138 }
 139
 140 enum LoadResult {
 141     Previous(CrateNum),
 142     Loaded(Library),
 143 }
 144
 145 impl<'a> CrateLoader<'a> {
 146     pub fn new(sess: &'a Session, cstore: &'a CStore, local_crate_name: &str) -> Self {
 147         CrateLoader {
 148             sess: sess,
 149             cstore: cstore,
 150             next_crate_num: cstore.next_crate_num(),
 151             foreign_item_map: FnvHashMap(),
 152             local_crate_name: local_crate_name.to_owned(),
 153         }
 154     }
 155
 156     fn extract_crate_info(&self, i: &ast::Item) -> Option<ExternCrateInfo> {
 157         match i.node {
 158             ast::ItemKind::ExternCrate(ref path_opt) => {
 159                 debug!("resolving extern crate stmt. ident: {} path_opt: {:?}",
 160                        i.ident, path_opt);
 161                 let name = match *path_opt {
 162                     Some(name) => {
 163                         validate_crate_name(Some(self.sess), &name.as_str(),
 164                                             Some(i.span));
 165                         name.to_string()
 166                     }
 167                     None => i.ident.to_string(),
 168                 };
 169                 Some(ExternCrateInfo {
 170                     ident: i.ident.to_string(),
 171                     name: name,
 172                     id: i.id,
 173                     should_link: should_link(i),
 174                 })
 175             }
 176             _ => None
 177         }
 178     }
 179
 180     fn existing_match(&self, name: &str, hash: Option<&Svh>, kind: PathKind)
 181                       -> Option<CrateNum> {
 182         let mut ret = None;
 183         self.cstore.iter_crate_data(|cnum, data| {
 184             if data.name != name { return }
 185
 186             match hash {
 187                 Some(hash) if *hash == data.hash() => { ret = Some(cnum); return }
 188                 Some(..) => return,
 189                 None => {}
 190             }
 191
 192             // When the hash is None we're dealing with a top-level dependency
 193             // in which case we may have a specification on the command line for
 194             // this library. Even though an upstream library may have loaded
 195             // something of the same name, we have to make sure it was loaded
 196             // from the exact same location as well.
 197             //
 198             // We're also sure to compare *paths*, not actual byte slices. The
 199             // `source` stores paths which are normalized which may be different
 200             // from the strings on the command line.
 201             let source = self.cstore.used_crate_source(cnum);
 202             if let Some(locs) = self.sess.opts.externs.get(name) {
 203                 let found = locs.iter().any(|l| {
 204                     let l = fs::canonicalize(l).ok();
 205                     source.dylib.as_ref().map(|p| &p.0) == l.as_ref() ||
 206                     source.rlib.as_ref().map(|p| &p.0) == l.as_ref()
 207                 });
 208                 if found {
 209                     ret = Some(cnum);
 210                 }
 211                 return
 212             }
 213
 214             // Alright, so we've gotten this far which means that `data` has the
 215             // right name, we don't have a hash, and we don't have a --extern
 216             // pointing for ourselves. We're still not quite yet done because we
 217             // have to make sure that this crate was found in the crate lookup
 218             // path (this is a top-level dependency) as we don't want to
 219             // implicitly load anything inside the dependency lookup path.
 220             let prev_kind = source.dylib.as_ref().or(source.rlib.as_ref())
 221                                   .unwrap().1;
 222             if ret.is_none() && (prev_kind == kind || prev_kind == PathKind::All) {
 223                 ret = Some(cnum);
 224             }
 225         });
 226         return ret;
 227     }
 228
 229     fn verify_no_symbol_conflicts(&self,
 230                                   span: Span,
 231                                   root: &CrateRoot) {
 232         // Check for (potential) conflicts with the local crate
 233         if self.local_crate_name == root.name &&
 234            self.sess.local_crate_disambiguator() == &root.disambiguator[..] {
 235             span_fatal!(self.sess, span, E0519,
 236                         "the current crate is indistinguishable from one of its \
 237                          dependencies: it has the same crate-name `{}` and was \
 238                          compiled with the same `-C metadata` arguments. This \
 239                          will result in symbol conflicts between the two.",
 240                         root.name)
 241         }
 242
 243         // Check for conflicts with any crate loaded so far
 244         self.cstore.iter_crate_data(|_, other| {
 245             if other.name() == root.name && // same crate-name
 246                other.disambiguator() == root.disambiguator &&  // same crate-disambiguator
 247                other.hash() != root.hash { // but different SVH
 248                 span_fatal!(self.sess, span, E0523,
 249                         "found two different crates with name `{}` that are \
 250                          not distinguished by differing `-C metadata`. This \
 251                          will result in symbol conflicts between the two.",
 252                         root.name)
 253             }
 254         });
 255     }
 256
 257     fn register_crate(&mut self,
 258                       root: &Option<CratePaths>,
 259                       ident: &str,
 260                       name: &str,
 261                       span: Span,
 262                       lib: Library,
 263                       explicitly_linked: bool)
 264                       -> (CrateNum, Rc<cstore::CrateMetadata>,
 265                           cstore::CrateSource) {
 266         info!("register crate `extern crate {} as {}`", name, ident);
 267         let crate_root = lib.metadata.get_root();
 268         self.verify_no_symbol_conflicts(span, &crate_root);
 269
 270         // Claim this crate number and cache it
 271         let cnum = self.next_crate_num;
 272         self.next_crate_num = CrateNum::from_u32(cnum.as_u32() + 1);
 273
 274         // Stash paths for top-most crate locally if necessary.
 275         let crate_paths = if root.is_none() {
 276             Some(CratePaths {
 277                 ident: ident.to_string(),
 278                 dylib: lib.dylib.clone().map(|p| p.0),
 279                 rlib:  lib.rlib.clone().map(|p| p.0),
 280             })
 281         } else {
 282             None
 283         };
 284         // Maintain a reference to the top most crate.
 285         let root = if root.is_some() { root } else { &crate_paths };
 286
 287         let Library { dylib, rlib, metadata } = lib;
 288
 289         let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, span);
 290
 291         if crate_root.macro_derive_registrar.is_some() {
 292             self.sess.span_err(span, "crates of the `proc-macro` crate type \
 293                                       cannot be linked at runtime");
 294         }
 295
 296         let cmeta = Rc::new(cstore::CrateMetadata {
 297             name: name.to_string(),
 298             extern_crate: Cell::new(None),
 299             key_map: metadata.load_key_map(crate_root.index),
 300             root: crate_root,
 301             blob: metadata,
 302             cnum_map: RefCell::new(cnum_map),
 303             cnum: cnum,
 304             codemap_import_info: RefCell::new(vec![]),
 305             explicitly_linked: Cell::new(explicitly_linked),
 306         });
 307
 308         let source = cstore::CrateSource {
 309             dylib: dylib,
 310             rlib: rlib,
 311             cnum: cnum,
 312         };
 313
 314         self.cstore.set_crate_data(cnum, cmeta.clone());
 315         self.cstore.add_used_crate_source(source.clone());
 316         (cnum, cmeta, source)
 317     }
 318
 319     fn resolve_crate(&mut self,
 320                      root: &Option<CratePaths>,
 321                      ident: &str,
 322                      name: &str,
 323                      hash: Option<&Svh>,
 324                      span: Span,
 325                      kind: PathKind,
 326                      explicitly_linked: bool)
 327                      -> (CrateNum, Rc<cstore::CrateMetadata>, cstore::CrateSource) {
 328         info!("resolving crate `extern crate {} as {}`", name, ident);
 329         let result = match self.existing_match(name, hash, kind) {
 330             Some(cnum) => LoadResult::Previous(cnum),
 331             None => {
 332                 info!("falling back to a load");
 333                 let mut locate_ctxt = locator::Context {
 334                     sess: self.sess,
 335                     span: span,
 336                     ident: ident,
 337                     crate_name: name,
 338                     hash: hash.map(|a| &*a),
 339                     filesearch: self.sess.target_filesearch(kind),
 340                     target: &self.sess.target.target,
 341                     triple: &self.sess.opts.target_triple,
 342                     root: root,
 343                     rejected_via_hash: vec![],
 344                     rejected_via_triple: vec![],
 345                     rejected_via_kind: vec![],
 346                     rejected_via_version: vec![],
 347                     should_match_name: true,
 348                 };
 349                 match self.load(&mut locate_ctxt) {
 350                     Some(result) => result,
 351                     None => locate_ctxt.report_errs(),
 352                 }
 353             }
 354         };
 355
 356         match result {
 357             LoadResult::Previous(cnum) => {
 358                 let data = self.cstore.get_crate_data(cnum);
 359                 if explicitly_linked && !data.explicitly_linked.get() {
 360                     data.explicitly_linked.set(explicitly_linked);
 361                 }
 362                 (cnum, data, self.cstore.used_crate_source(cnum))
 363             }
 364             LoadResult::Loaded(library) => {
 365                 self.register_crate(root, ident, name, span, library,
 366                                     explicitly_linked)
 367             }
 368         }
 369     }
 370
 371     fn load(&mut self, locate_ctxt: &mut locator::Context) -> Option<LoadResult> {
 372         let library = match locate_ctxt.maybe_load_library_crate() {
 373             Some(lib) => lib,
 374             None => return None,
 375         };
 376
 377         // In the case that we're loading a crate, but not matching
 378         // against a hash, we could load a crate which has the same hash
 379         // as an already loaded crate. If this is the case prevent
 380         // duplicates by just using the first crate.
 381         //
 382         // Note that we only do this for target triple crates, though, as we
 383         // don't want to match a host crate against an equivalent target one
 384         // already loaded.
 385         let root = library.metadata.get_root();
 386         if locate_ctxt.triple == self.sess.opts.target_triple {
 387             let mut result = LoadResult::Loaded(library);
 388             self.cstore.iter_crate_data(|cnum, data| {
 389                 if data.name() == root.name && root.hash == data.hash() {
 390                     assert!(locate_ctxt.hash.is_none());
 391                     info!("load success, going to previous cnum: {}", cnum);
 392                     result = LoadResult::Previous(cnum);
 393                 }
 394             });
 395             Some(result)
 396         } else {
 397             Some(LoadResult::Loaded(library))
 398         }
 399     }
 400
 401     fn update_extern_crate(&mut self,
 402                            cnum: CrateNum,
 403                            mut extern_crate: ExternCrate,
 404                            visited: &mut FnvHashSet<(CrateNum, bool)>)
 405     {
 406         if !visited.insert((cnum, extern_crate.direct)) { return }
 407
 408         let cmeta = self.cstore.get_crate_data(cnum);
 409         let old_extern_crate = cmeta.extern_crate.get();
 410
 411         // Prefer:
 412         // - something over nothing (tuple.0);
 413         // - direct extern crate to indirect (tuple.1);
 414         // - shorter paths to longer (tuple.2).
 415         let new_rank = (true, extern_crate.direct, !extern_crate.path_len);
 416         let old_rank = match old_extern_crate {
 417             None => (false, false, !0),
 418             Some(ref c) => (true, c.direct, !c.path_len),
 419         };
 420
 421         if old_rank >= new_rank {
 422             return; // no change needed
 423         }
 424
 425         cmeta.extern_crate.set(Some(extern_crate));
 426         // Propagate the extern crate info to dependencies.
 427         extern_crate.direct = false;
 428         for &dep_cnum in cmeta.cnum_map.borrow().iter() {
 429             self.update_extern_crate(dep_cnum, extern_crate, visited);
 430         }
 431     }
 432
 433     // Go through the crate metadata and load any crates that it references
 434     fn resolve_crate_deps(&mut self,
 435                           root: &Option<CratePaths>,
 436                           crate_root: &CrateRoot,
 437                           metadata: &MetadataBlob,
 438                           krate: CrateNum,
 439                           span: Span)
 440                           -> cstore::CrateNumMap {
 441         debug!("resolving deps of external crate");
 442         // The map from crate numbers in the crate we're resolving to local crate
 443         // numbers
 444         let deps = crate_root.crate_deps.decode(metadata);
 445         let map: FnvHashMap<_, _> = deps.enumerate().map(|(crate_num, dep)| {
 446             debug!("resolving dep crate {} hash: `{}`", dep.name, dep.hash);
 447             let (local_cnum, ..) = self.resolve_crate(root,
 448                                                         &dep.name.as_str(),
 449                                                         &dep.name.as_str(),
 450                                                         Some(&dep.hash),
 451                                                         span,
 452                                                         PathKind::Dependency,
 453                                                         dep.explicitly_linked);
 454             (CrateNum::new(crate_num + 1), local_cnum)
 455         }).collect();
 456
 457         let max_cnum = map.values().cloned().max().map(|cnum| cnum.as_u32()).unwrap_or(0);
 458
 459         // we map 0 and all other holes in the map to our parent crate. The "additional"
 460         // self-dependencies should be harmless.
 461         (0..max_cnum+1).map(|cnum| {
 462             map.get(&CrateNum::from_u32(cnum)).cloned().unwrap_or(krate)
 463         }).collect()
 464     }
 465
 466     fn read_extension_crate(&mut self, span: Span, info: &ExternCrateInfo) -> ExtensionCrate {
 467         info!("read extension crate {} `extern crate {} as {}` linked={}",
 468               info.id, info.name, info.ident, info.should_link);
 469         let target_triple = &self.sess.opts.target_triple[..];
 470         let is_cross = target_triple != config::host_triple();
 471         let mut target_only = false;
 472         let ident = info.ident.clone();
 473         let name = info.name.clone();
 474         let mut locate_ctxt = locator::Context {
 475             sess: self.sess,
 476             span: span,
 477             ident: &ident[..],
 478             crate_name: &name[..],
 479             hash: None,
 480             filesearch: self.sess.host_filesearch(PathKind::Crate),
 481             target: &self.sess.host,
 482             triple: config::host_triple(),
 483             root: &None,
 484             rejected_via_hash: vec![],
 485             rejected_via_triple: vec![],
 486             rejected_via_kind: vec![],
 487             rejected_via_version: vec![],
 488             should_match_name: true,
 489         };
 490         let library = self.load(&mut locate_ctxt).or_else(|| {
 491             if !is_cross {
 492                 return None
 493             }
 494             // Try loading from target crates. This will abort later if we
 495             // try to load a plugin registrar function,
 496             target_only = true;
 497
 498             locate_ctxt.target = &self.sess.target.target;
 499             locate_ctxt.triple = target_triple;
 500             locate_ctxt.filesearch = self.sess.target_filesearch(PathKind::Crate);
 501
 502             self.load(&mut locate_ctxt)
 503         });
 504         let library = match library {
 505             Some(l) => l,
 506             None => locate_ctxt.report_errs(),
 507         };
 508
 509         let (dylib, metadata) = match library {
 510             LoadResult::Previous(cnum) => {
 511                 let dylib = self.cstore.opt_used_crate_source(cnum).unwrap().dylib;
 512                 let data = self.cstore.get_crate_data(cnum);
 513                 (dylib, PMDSource::Registered(data))
 514             }
 515             LoadResult::Loaded(library) => {
 516                 let dylib = library.dylib.clone();
 517                 let metadata = PMDSource::Owned(library);
 518                 (dylib, metadata)
 519             }
 520         };
 521
 522         ExtensionCrate {
 523             metadata: metadata,
 524             dylib: dylib.map(|p| p.0),
 525             target_only: target_only,
 526         }
 527     }
 528
 529     fn read_macros(&mut self, item: &ast::Item, ekrate: &ExtensionCrate) -> LoadedMacros {
 530         let root = ekrate.metadata.get_root();
 531         let source_name = format!("<{} macros>", item.ident);
 532         let mut macro_rules = Vec::new();
 533
 534         for def in root.macro_defs.decode(&*ekrate.metadata) {
 535             // NB: Don't use parse::parse_tts_from_source_str because it parses with
 536             // quote_depth > 0.
 537             let mut p = parse::new_parser_from_source_str(&self.sess.parse_sess,
 538                                                           source_name.clone(),
 539                                                           def.body);
 540             let lo = p.span.lo;
 541             let body = match p.parse_all_token_trees() {
 542                 Ok(body) => body,
 543                 Err(mut err) => {
 544                     err.emit();
 545                     self.sess.abort_if_errors();
 546                     unreachable!();
 547                 }
 548             };
 549             let local_span = mk_sp(lo, p.prev_span.hi);
 550
 551             // Mark the attrs as used
 552             for attr in &def.attrs {
 553                 attr::mark_used(attr);
 554             }
 555
 556             macro_rules.push(ast::MacroDef {
 557                 ident: ast::Ident::with_empty_ctxt(def.name),
 558                 id: ast::DUMMY_NODE_ID,
 559                 span: local_span,
 560                 imported_from: Some(item.ident),
 561                 allow_internal_unstable: attr::contains_name(&def.attrs, "allow_internal_unstable"),
 562                 attrs: def.attrs,
 563                 body: body,
 564             });
 565             self.sess.imported_macro_spans.borrow_mut()
 566                 .insert(local_span, (def.name.as_str().to_string(), def.span));
 567         }
 568
 569         if let Some(id) = root.macro_derive_registrar {
 570             let dylib = match ekrate.dylib.clone() {
 571                 Some(dylib) => dylib,
 572                 None => span_bug!(item.span, "proc-macro crate not dylib"),
 573             };
 574             if ekrate.target_only {
 575                 let message = format!("proc-macro crate is not available for \
 576                                        triple `{}` (only found {})",
 577                                       config::host_triple(),
 578                                       self.sess.opts.target_triple);
 579                 self.sess.span_fatal(item.span, &message);
 580             }
 581
 582             // custom derive crates currently should not have any macro_rules!
 583             // exported macros, enforced elsewhere
 584             assert_eq!(macro_rules.len(), 0);
 585             LoadedMacros::ProcMacros(self.load_derive_macros(item, id, root.hash, dylib))
 586         } else {
 587             LoadedMacros::MacroRules(macro_rules)
 588         }
 589     }
 590
 591     /// Load custom derive macros.
 592     ///
 593     /// Note that this is intentionally similar to how we load plugins today,
 594     /// but also intentionally separate. Plugins are likely always going to be
 595     /// implemented as dynamic libraries, but we have a possible future where
 596     /// custom derive (and other macro-1.1 style features) are implemented via
 597     /// executables and custom IPC.
 598     fn load_derive_macros(&mut self, item: &ast::Item, index: DefIndex, svh: Svh, path: PathBuf)
 599                           -> Vec<(ast::Name, SyntaxExtension)> {
 600         use std::{env, mem};
 601         use proc_macro::TokenStream;
 602         use proc_macro::__internal::Registry;
 603         use rustc_back::dynamic_lib::DynamicLibrary;
 604         use syntax_ext::deriving::custom::CustomDerive;
 605
 606         // Make sure the path contains a / or the linker will search for it.
 607         let path = env::current_dir().unwrap().join(path);
 608         let lib = match DynamicLibrary::open(Some(&path)) {
 609             Ok(lib) => lib,
 610             Err(err) => self.sess.span_fatal(item.span, &err),
 611         };
 612
 613         let sym = self.sess.generate_derive_registrar_symbol(&svh, index);
 614         let registrar = unsafe {
 615             let sym = match lib.symbol(&sym) {
 616                 Ok(f) => f,
 617                 Err(err) => self.sess.span_fatal(item.span, &err),
 618             };
 619             mem::transmute::<*mut u8, fn(&mut Registry)>(sym)
 620         };
 621
 622         struct MyRegistrar(Vec<(ast::Name, SyntaxExtension)>);
 623
 624         impl Registry for MyRegistrar {
 625             fn register_custom_derive(&mut self,
 626                                       trait_name: &str,
 627                                       expand: fn(TokenStream) -> TokenStream) {
 628                 let derive = SyntaxExtension::CustomDerive(Box::new(CustomDerive::new(expand)));
 629                 self.0.push((intern(trait_name), derive));
 630             }
 631         }
 632
 633         let mut my_registrar = MyRegistrar(Vec::new());
 634         registrar(&mut my_registrar);
 635
 636         // Intentionally leak the dynamic library. We can't ever unload it
 637         // since the library can make things that will live arbitrarily long.
 638         mem::forget(lib);
 639         my_registrar.0
 640     }
 641
 642     /// Look for a plugin registrar. Returns library path, crate
 643     /// SVH and DefIndex of the registrar function.
 644     pub fn find_plugin_registrar(&mut self, span: Span, name: &str)
 645                                  -> Option<(PathBuf, Svh, DefIndex)> {
 646         let ekrate = self.read_extension_crate(span, &ExternCrateInfo {
 647              name: name.to_string(),
 648              ident: name.to_string(),
 649              id: ast::DUMMY_NODE_ID,
 650              should_link: false,
 651         });
 652
 653         if ekrate.target_only {
 654             // Need to abort before syntax expansion.
 655             let message = format!("plugin `{}` is not available for triple `{}` \
 656                                    (only found {})",
 657                                   name,
 658                                   config::host_triple(),
 659                                   self.sess.opts.target_triple);
 660             span_fatal!(self.sess, span, E0456, "{}", &message[..]);
 661         }
 662
 663         let root = ekrate.metadata.get_root();
 664         match (ekrate.dylib.as_ref(), root.plugin_registrar_fn) {
 665             (Some(dylib), Some(reg)) => {
 666                 Some((dylib.to_path_buf(), root.hash, reg))
 667             }
 668             (None, Some(_)) => {
 669                 span_err!(self.sess, span, E0457,
 670                           "plugin `{}` only found in rlib format, but must be available \
 671                            in dylib format",
 672                           name);
 673                 // No need to abort because the loading code will just ignore this
 674                 // empty dylib.
 675                 None
 676             }
 677             _ => None,
 678         }
 679     }
 680
 681     fn register_statically_included_foreign_items(&mut self) {
 682         let libs = self.cstore.get_used_libraries();
 683         for (lib, list) in self.foreign_item_map.iter() {
 684             let is_static = libs.borrow().iter().any(|&(ref name, kind)| {
 685                 lib == name && kind == cstore::NativeStatic
 686             });
 687             if is_static {
 688                 for id in list {
 689                     self.cstore.add_statically_included_foreign_item(*id);
 690                 }
 691             }
 692         }
 693     }
 694
 695     fn inject_panic_runtime(&mut self, krate: &ast::Crate) {
 696         // If we're only compiling an rlib, then there's no need to select a
 697         // panic runtime, so we just skip this section entirely.
 698         let any_non_rlib = self.sess.crate_types.borrow().iter().any(|ct| {
 699             *ct != config::CrateTypeRlib
 700         });
 701         if !any_non_rlib {
 702             info!("panic runtime injection skipped, only generating rlib");
 703             return
 704         }
 705
 706         // If we need a panic runtime, we try to find an existing one here. At
 707         // the same time we perform some general validation of the DAG we've got
 708         // going such as ensuring everything has a compatible panic strategy.
 709         //
 710         // The logic for finding the panic runtime here is pretty much the same
 711         // as the allocator case with the only addition that the panic strategy
 712         // compilation mode also comes into play.
 713         let desired_strategy = self.sess.panic_strategy();
 714         let mut runtime_found = false;
 715         let mut needs_panic_runtime = attr::contains_name(&krate.attrs,
 716                                                           "needs_panic_runtime");
 717         self.cstore.iter_crate_data(|cnum, data| {
 718             needs_panic_runtime = needs_panic_runtime || data.needs_panic_runtime();
 719             if data.is_panic_runtime() {
 720                 // Inject a dependency from all #![needs_panic_runtime] to this
 721                 // #![panic_runtime] crate.
 722                 self.inject_dependency_if(cnum, "a panic runtime",
 723                                           &|data| data.needs_panic_runtime());
 724                 runtime_found = runtime_found || data.explicitly_linked.get();
 725             }
 726         });
 727
 728         // If an explicitly linked and matching panic runtime was found, or if
 729         // we just don't need one at all, then we're done here and there's
 730         // nothing else to do.
 731         if !needs_panic_runtime || runtime_found {
 732             return
 733         }
 734
 735         // By this point we know that we (a) need a panic runtime and (b) no
 736         // panic runtime was explicitly linked. Here we just load an appropriate
 737         // default runtime for our panic strategy and then inject the
 738         // dependencies.
 739         //
 740         // We may resolve to an already loaded crate (as the crate may not have
 741         // been explicitly linked prior to this) and we may re-inject
 742         // dependencies again, but both of those situations are fine.
 743         //
 744         // Also note that we have yet to perform validation of the crate graph
 745         // in terms of everyone has a compatible panic runtime format, that's
 746         // performed later as part of the `dependency_format` module.
 747         let name = match desired_strategy {
 748             PanicStrategy::Unwind => "panic_unwind",
 749             PanicStrategy::Abort => "panic_abort",
 750         };
 751         info!("panic runtime not found -- loading {}", name);
 752
 753         let (cnum, data, _) = self.resolve_crate(&None, name, name, None,
 754                                                  syntax_pos::DUMMY_SP,
 755                                                  PathKind::Crate, false);
 756
 757         // Sanity check the loaded crate to ensure it is indeed a panic runtime
 758         // and the panic strategy is indeed what we thought it was.
 759         if !data.is_panic_runtime() {
 760             self.sess.err(&format!("the crate `{}` is not a panic runtime",
 761                                    name));
 762         }
 763         if data.panic_strategy() != desired_strategy {
 764             self.sess.err(&format!("the crate `{}` does not have the panic \
 765                                     strategy `{}`",
 766                                    name, desired_strategy.desc()));
 767         }
 768
 769         self.sess.injected_panic_runtime.set(Some(cnum));
 770         self.inject_dependency_if(cnum, "a panic runtime",
 771                                   &|data| data.needs_panic_runtime());
 772     }
 773
 774     fn inject_allocator_crate(&mut self) {
 775         // Make sure that we actually need an allocator, if none of our
 776         // dependencies need one then we definitely don't!
 777         //
 778         // Also, if one of our dependencies has an explicit allocator, then we
 779         // also bail out as we don't need to implicitly inject one.
 780         let mut needs_allocator = false;
 781         let mut found_required_allocator = false;
 782         self.cstore.iter_crate_data(|cnum, data| {
 783             needs_allocator = needs_allocator || data.needs_allocator();
 784             if data.is_allocator() {
 785                 info!("{} required by rlib and is an allocator", data.name());
 786                 self.inject_dependency_if(cnum, "an allocator",
 787                                           &|data| data.needs_allocator());
 788                 found_required_allocator = found_required_allocator ||
 789                     data.explicitly_linked.get();
 790             }
 791         });
 792         if !needs_allocator || found_required_allocator { return }
 793
 794         // At this point we've determined that we need an allocator and no
 795         // previous allocator has been activated. We look through our outputs of
 796         // crate types to see what kind of allocator types we may need.
 797         //
 798         // The main special output type here is that rlibs do **not** need an
 799         // allocator linked in (they're just object files), only final products
 800         // (exes, dylibs, staticlibs) need allocators.
 801         let mut need_lib_alloc = false;
 802         let mut need_exe_alloc = false;
 803         for ct in self.sess.crate_types.borrow().iter() {
 804             match *ct {
 805                 config::CrateTypeExecutable => need_exe_alloc = true,
 806                 config::CrateTypeDylib |
 807                 config::CrateTypeProcMacro |
 808                 config::CrateTypeCdylib |
 809                 config::CrateTypeStaticlib => need_lib_alloc = true,
 810                 config::CrateTypeRlib => {}
 811             }
 812         }
 813         if !need_lib_alloc && !need_exe_alloc { return }
 814
 815         // The default allocator crate comes from the custom target spec, and we
 816         // choose between the standard library allocator or exe allocator. This
 817         // distinction exists because the default allocator for binaries (where
 818         // the world is Rust) is different than library (where the world is
 819         // likely *not* Rust).
 820         //
 821         // If a library is being produced, but we're also flagged with `-C
 822         // prefer-dynamic`, then we interpret this as a *Rust* dynamic library
 823         // is being produced so we use the exe allocator instead.
 824         //
 825         // What this boils down to is:
 826         //
 827         // * Binaries use jemalloc
 828         // * Staticlibs and Rust dylibs use system malloc
 829         // * Rust dylibs used as dependencies to rust use jemalloc
 830         let name = if need_lib_alloc && !self.sess.opts.cg.prefer_dynamic {
 831             &self.sess.target.target.options.lib_allocation_crate
 832         } else {
 833             &self.sess.target.target.options.exe_allocation_crate
 834         };
 835         let (cnum, data, _) = self.resolve_crate(&None, name, name, None,
 836                                                  syntax_pos::DUMMY_SP,
 837                                                  PathKind::Crate, false);
 838
 839         // Sanity check the crate we loaded to ensure that it is indeed an
 840         // allocator.
 841         if !data.is_allocator() {
 842             self.sess.err(&format!("the allocator crate `{}` is not tagged \
 843                                     with #![allocator]", data.name()));
 844         }
 845
 846         self.sess.injected_allocator.set(Some(cnum));
 847         self.inject_dependency_if(cnum, "an allocator",
 848                                   &|data| data.needs_allocator());
 849     }
 850
 851     fn inject_dependency_if(&self,
 852                             krate: CrateNum,
 853                             what: &str,
 854                             needs_dep: &Fn(&cstore::CrateMetadata) -> bool) {
 855         // don't perform this validation if the session has errors, as one of
 856         // those errors may indicate a circular dependency which could cause
 857         // this to stack overflow.
 858         if self.sess.has_errors() {
 859             return
 860         }
 861
 862         // Before we inject any dependencies, make sure we don't inject a
 863         // circular dependency by validating that this crate doesn't
 864         // transitively depend on any crates satisfying `needs_dep`.
 865         for dep in self.cstore.crate_dependencies_in_rpo(krate) {
 866             let data = self.cstore.get_crate_data(dep);
 867             if needs_dep(&data) {
 868                 self.sess.err(&format!("the crate `{}` cannot depend \
 869                                         on a crate that needs {}, but \
 870                                         it depends on `{}`",
 871                                        self.cstore.get_crate_data(krate).name(),
 872                                        what,
 873                                        data.name()));
 874             }
 875         }
 876
 877         // All crates satisfying `needs_dep` do not explicitly depend on the
 878         // crate provided for this compile, but in order for this compilation to
 879         // be successfully linked we need to inject a dependency (to order the
 880         // crates on the command line correctly).
 881         self.cstore.iter_crate_data(|cnum, data| {
 882             if !needs_dep(data) {
 883                 return
 884             }
 885
 886             info!("injecting a dep from {} to {}", cnum, krate);
 887             data.cnum_map.borrow_mut().push(krate);
 888         });
 889     }
 890 }
 891
 892 impl<'a> CrateLoader<'a> {
 893     pub fn preprocess(&mut self, krate: &ast::Crate) {
 894         for attr in krate.attrs.iter().filter(|m| m.name() == "link_args") {
 895             if let Some(ref linkarg) = attr.value_str() {
 896                 self.cstore.add_used_link_args(&linkarg);
 897             }
 898         }
 899     }
 900
 901     fn process_foreign_mod(&mut self, i: &ast::Item, fm: &ast::ForeignMod) {
 902         if fm.abi == Abi::Rust || fm.abi == Abi::RustIntrinsic || fm.abi == Abi::PlatformIntrinsic {
 903             return;
 904         }
 905
 906         // First, add all of the custom #[link_args] attributes
 907         for m in i.attrs.iter().filter(|a| a.check_name("link_args")) {
 908             if let Some(linkarg) = m.value_str() {
 909                 self.cstore.add_used_link_args(&linkarg);
 910             }
 911         }
 912
 913         // Next, process all of the #[link(..)]-style arguments
 914         for m in i.attrs.iter().filter(|a| a.check_name("link")) {
 915             let items = match m.meta_item_list() {
 916                 Some(item) => item,
 917                 None => continue,
 918             };
 919             let kind = items.iter().find(|k| {
 920                 k.check_name("kind")
 921             }).and_then(|a| a.value_str());
 922             let kind = match kind.as_ref().map(|s| &s[..]) {
 923                 Some("static") => cstore::NativeStatic,
 924                 Some("dylib") => cstore::NativeUnknown,
 925                 Some("framework") => cstore::NativeFramework,
 926                 Some(k) => {
 927                     struct_span_err!(self.sess, m.span, E0458,
 928                               "unknown kind: `{}`", k)
 929                         .span_label(m.span, &format!("unknown kind")).emit();
 930                     cstore::NativeUnknown
 931                 }
 932                 None => cstore::NativeUnknown
 933             };
 934             let n = items.iter().find(|n| {
 935                 n.check_name("name")
 936             }).and_then(|a| a.value_str());
 937             let n = match n {
 938                 Some(n) => n,
 939                 None => {
 940                     struct_span_err!(self.sess, m.span, E0459,
 941                                      "#[link(...)] specified without `name = \"foo\"`")
 942                         .span_label(m.span, &format!("missing `name` argument")).emit();
 943                     InternedString::new("foo")
 944                 }
 945             };
 946             register_native_lib(self.sess, self.cstore, Some(m.span), n.to_string(), kind);
 947         }
 948
 949         // Finally, process the #[linked_from = "..."] attribute
 950         for m in i.attrs.iter().filter(|a| a.check_name("linked_from")) {
 951             let lib_name = match m.value_str() {
 952                 Some(name) => name,
 953                 None => continue,
 954             };
 955             let list = self.foreign_item_map.entry(lib_name.to_string())
 956                                                     .or_insert(Vec::new());
 957             list.extend(fm.items.iter().map(|it| it.id));
 958         }
 959     }
 960 }
 961
 962 impl<'a> middle::cstore::CrateLoader for CrateLoader<'a> {
 963     fn postprocess(&mut self, krate: &ast::Crate) {
 964         self.inject_allocator_crate();
 965         self.inject_panic_runtime(krate);
 966
 967         if log_enabled!(log::INFO) {
 968             dump_crates(&self.cstore);
 969         }
 970
 971         for &(ref name, kind) in &self.sess.opts.libs {
 972             register_native_lib(self.sess, self.cstore, None, name.clone(), kind);
 973         }
 974         self.register_statically_included_foreign_items();
 975     }
 976
 977     fn process_item(&mut self, item: &ast::Item, definitions: &Definitions, load_macros: bool)
 978                     -> Option<LoadedMacros> {
 979         match item.node {
 980             ast::ItemKind::ExternCrate(_) => {}
 981             ast::ItemKind::ForeignMod(ref fm) => {
 982                 self.process_foreign_mod(item, fm);
 983                 return None;
 984             }
 985             _ => return None,
 986         }
 987
 988         let info = self.extract_crate_info(item).unwrap();
 989         let loaded_macros = if load_macros {
 990             let ekrate = self.read_extension_crate(item.span, &info);
 991             let loaded_macros = self.read_macros(item, &ekrate);
 992
 993             // If this is a proc-macro crate or `#[no_link]` crate, it is only used at compile time,
 994             // so we return here to avoid registering the crate.
 995             if loaded_macros.is_proc_macros() || !info.should_link {
 996                 return Some(loaded_macros);
 997             }
 998
 999             // Register crate now to avoid double-reading metadata
1000             if let PMDSource::Owned(lib) = ekrate.metadata {
1001                 if ekrate.target_only || config::host_triple() == self.sess.opts.target_triple {
1002                     let ExternCrateInfo { ref ident, ref name, .. } = info;
1003                     self.register_crate(&None, ident, name, item.span, lib, true);
1004                 }
1005             }
1006
1007             Some(loaded_macros)
1008         } else {
1009             if !info.should_link {
1010                 return None;
1011             }
1012             None
1013         };
1014
1015         let (cnum, ..) = self.resolve_crate(
1016             &None, &info.ident, &info.name, None, item.span, PathKind::Crate, true,
1017         );
1018
1019         let def_id = definitions.opt_local_def_id(item.id).unwrap();
1020         let len = definitions.def_path(def_id.index).data.len();
1021
1022         let extern_crate =
1023             ExternCrate { def_id: def_id, span: item.span, direct: true, path_len: len };
1024         self.update_extern_crate(cnum, extern_crate, &mut FnvHashSet());
1025         self.cstore.add_extern_mod_stmt_cnum(info.id, cnum);
1026
1027         loaded_macros
1028     }
1029 }