src/librustc_driver/driver.rs

   1 // Copyright 2012-2013 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 use rustc::session::Session;
  12 use rustc::session::config::{self, Input, OutputFilenames};
  13 use rustc::session::search_paths::PathKind;
  14 use rustc::lint;
  15 use rustc::metadata::creader;
  16 use rustc::middle::{stability, ty, reachable};
  17 use rustc::middle::dependency_format;
  18 use rustc::middle;
  19 use rustc::plugin::load::Plugins;
  20 use rustc::plugin::registry::Registry;
  21 use rustc::plugin;
  22 use rustc::util::common::time;
  23 use rustc_borrowck as borrowck;
  24 use rustc_resolve as resolve;
  25 use rustc_trans::back::link;
  26 use rustc_trans::back::write;
  27 use rustc_trans::save;
  28 use rustc_trans::trans;
  29 use rustc_typeck as typeck;
  30
  31 use serialize::json;
  32
  33 use std::io;
  34 use std::io::fs;
  35 use std::os;
  36 use syntax::ast;
  37 use syntax::ast_map;
  38 use syntax::attr;
  39 use syntax::attr::{AttrMetaMethods};
  40 use syntax::diagnostics;
  41 use syntax::parse;
  42 use syntax::parse::token;
  43 use syntax;
  44
  45 pub fn compile_input(sess: Session,
  46                      cfg: ast::CrateConfig,
  47                      input: &Input,
  48                      outdir: &Option<Path>,
  49                      output: &Option<Path>,
  50                      addl_plugins: Option<Plugins>) {
  51     // We need nested scopes here, because the intermediate results can keep
  52     // large chunks of memory alive and we want to free them as soon as
  53     // possible to keep the peak memory usage low
  54     let (outputs, trans, sess) = {
  55         let (outputs, expanded_crate, id) = {
  56             let krate = phase_1_parse_input(&sess, cfg, input);
  57             if stop_after_phase_1(&sess) { return; }
  58             let outputs = build_output_filenames(input,
  59                                                  outdir,
  60                                                  output,
  61                                                  krate.attrs[],
  62                                                  &sess);
  63             let id = link::find_crate_name(Some(&sess), krate.attrs[],
  64                                            input);
  65             let expanded_crate
  66                 = match phase_2_configure_and_expand(&sess, krate, id[],
  67                                                      addl_plugins) {
  68                     None => return,
  69                     Some(k) => k
  70                 };
  71
  72             (outputs, expanded_crate, id)
  73         };
  74
  75         let mut forest = ast_map::Forest::new(expanded_crate);
  76         let ast_map = assign_node_ids_and_map(&sess, &mut forest);
  77
  78         write_out_deps(&sess, input, &outputs, id[]);
  79
  80         if stop_after_phase_2(&sess) { return; }
  81
  82         let arenas = ty::CtxtArenas::new();
  83         let analysis = phase_3_run_analysis_passes(sess, ast_map, &arenas, id);
  84         phase_save_analysis(&analysis.ty_cx.sess, analysis.ty_cx.map.krate(), &analysis, outdir);
  85
  86         if log_enabled!(::log::INFO) {
  87             println!("Pre-trans");
  88             analysis.ty_cx.print_debug_stats();
  89         }
  90
  91         if stop_after_phase_3(&analysis.ty_cx.sess) { return; }
  92         let (tcx, trans) = phase_4_translate_to_llvm(analysis);
  93
  94         if log_enabled!(::log::INFO) {
  95             println!("Post-trans");
  96             tcx.print_debug_stats();
  97         }
  98
  99         // Discard interned strings as they are no longer required.
 100         token::get_ident_interner().clear();
 101
 102         (outputs, trans, tcx.sess)
 103     };
 104     phase_5_run_llvm_passes(&sess, &trans, &outputs);
 105     if stop_after_phase_5(&sess) { return; }
 106     phase_6_link_output(&sess, &trans, &outputs);
 107 }
 108
 109 /// The name used for source code that doesn't originate in a file
 110 /// (e.g. source from stdin or a string)
 111 pub fn anon_src() -> String {
 112     "<anon>".to_string()
 113 }
 114
 115 pub fn source_name(input: &Input) -> String {
 116     match *input {
 117         // FIXME (#9639): This needs to handle non-utf8 paths
 118         Input::File(ref ifile) => ifile.as_str().unwrap().to_string(),
 119         Input::Str(_) => anon_src()
 120     }
 121 }
 122
 123 pub fn phase_1_parse_input(sess: &Session, cfg: ast::CrateConfig, input: &Input)
 124     -> ast::Crate {
 125     // These may be left in an incoherent state after a previous compile.
 126     // `clear_tables` and `get_ident_interner().clear()` can be used to free
 127     // memory, but they do not restore the initial state.
 128     syntax::ext::mtwt::reset_tables();
 129     token::reset_ident_interner();
 130
 131     let krate = time(sess.time_passes(), "parsing", (), |_| {
 132         match *input {
 133             Input::File(ref file) => {
 134                 parse::parse_crate_from_file(&(*file), cfg.clone(), &sess.parse_sess)
 135             }
 136             Input::Str(ref src) => {
 137                 parse::parse_crate_from_source_str(anon_src().to_string(),
 138                                                    src.to_string(),
 139                                                    cfg.clone(),
 140                                                    &sess.parse_sess)
 141             }
 142         }
 143     });
 144
 145     if sess.opts.debugging_opts & config::AST_JSON_NOEXPAND != 0 {
 146         println!("{}", json::as_json(&krate));
 147     }
 148
 149     if let Some(ref s) = sess.opts.show_span {
 150         syntax::show_span::run(sess.diagnostic(), s.as_slice(), &krate);
 151     }
 152
 153     krate
 154 }
 155
 156 // For continuing compilation after a parsed crate has been
 157 // modified
 158
 159 /// Run the "early phases" of the compiler: initial `cfg` processing,
 160 /// loading compiler plugins (including those from `addl_plugins`),
 161 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 162 /// harness if one is to be provided and injection of a dependency on the
 163 /// standard library and prelude.
 164 ///
 165 /// Returns `None` if we're aborting after handling -W help.
 166 pub fn phase_2_configure_and_expand(sess: &Session,
 167                                     mut krate: ast::Crate,
 168                                     crate_name: &str,
 169                                     addl_plugins: Option<Plugins>)
 170                                     -> Option<ast::Crate> {
 171     let time_passes = sess.time_passes();
 172
 173     *sess.crate_types.borrow_mut() =
 174         collect_crate_types(sess, krate.attrs[]);
 175     *sess.crate_metadata.borrow_mut() =
 176         collect_crate_metadata(sess, krate.attrs[]);
 177
 178     time(time_passes, "recursion limit", (), |_| {
 179         middle::recursion_limit::update_recursion_limit(sess, &krate);
 180     });
 181
 182     // strip before expansion to allow macros to depend on
 183     // configuration variables e.g/ in
 184     //
 185     //   #[macro_escape] #[cfg(foo)]
 186     //   mod bar { macro_rules! baz!(() => {{}}) }
 187     //
 188     // baz! should not use this definition unless foo is enabled.
 189
 190     time(time_passes, "gated macro checking", (), |_| {
 191         let (features, unknown_features) =
 192             syntax::feature_gate::check_crate_macros(sess.codemap(),
 193                                                      &sess.parse_sess.span_diagnostic,
 194                                                      &krate);
 195         for uf in unknown_features.iter() {
 196             sess.add_lint(lint::builtin::UNKNOWN_FEATURES,
 197                           ast::CRATE_NODE_ID,
 198                           *uf,
 199                           "unknown feature".to_string());
 200         }
 201
 202         // these need to be set "early" so that expansion sees `quote` if enabled.
 203         *sess.features.borrow_mut() = features;
 204         sess.abort_if_errors();
 205     });
 206
 207     krate = time(time_passes, "configuration 1", krate, |krate|
 208                  syntax::config::strip_unconfigured_items(sess.diagnostic(), krate));
 209
 210     krate = time(time_passes, "crate injection", krate, |krate|
 211                  syntax::std_inject::maybe_inject_crates_ref(krate,
 212                                                              sess.opts.alt_std_name.clone()));
 213
 214     let mut addl_plugins = Some(addl_plugins);
 215     let Plugins { macros, registrars }
 216         = time(time_passes, "plugin loading", (), |_|
 217                plugin::load::load_plugins(sess, &krate, addl_plugins.take().unwrap()));
 218
 219     let mut registry = Registry::new(&krate);
 220
 221     time(time_passes, "plugin registration", (), |_| {
 222         if sess.features.borrow().rustc_diagnostic_macros {
 223             registry.register_macro("__diagnostic_used",
 224                 diagnostics::plugin::expand_diagnostic_used);
 225             registry.register_macro("__register_diagnostic",
 226                 diagnostics::plugin::expand_register_diagnostic);
 227             registry.register_macro("__build_diagnostic_array",
 228                 diagnostics::plugin::expand_build_diagnostic_array);
 229         }
 230
 231         for &registrar in registrars.iter() {
 232             registrar(&mut registry);
 233         }
 234     });
 235
 236     let Registry { syntax_exts, lint_passes, lint_groups, .. } = registry;
 237
 238     {
 239         let mut ls = sess.lint_store.borrow_mut();
 240         for pass in lint_passes.into_iter() {
 241             ls.register_pass(Some(sess), true, pass);
 242         }
 243
 244         for (name, to) in lint_groups.into_iter() {
 245             ls.register_group(Some(sess), true, name, to);
 246         }
 247     }
 248
 249     // Lint plugins are registered; now we can process command line flags.
 250     if sess.opts.describe_lints {
 251         super::describe_lints(&*sess.lint_store.borrow(), true);
 252         return None;
 253     }
 254     sess.lint_store.borrow_mut().process_command_line(sess);
 255
 256     // Abort if there are errors from lint processing or a plugin registrar.
 257     sess.abort_if_errors();
 258
 259     krate = time(time_passes, "expansion", (krate, macros, syntax_exts),
 260         |(krate, macros, syntax_exts)| {
 261             // Windows dlls do not have rpaths, so they don't know how to find their
 262             // dependencies. It's up to us to tell the system where to find all the
 263             // dependent dlls. Note that this uses cfg!(windows) as opposed to
 264             // targ_cfg because syntax extensions are always loaded for the host
 265             // compiler, not for the target.
 266             let mut _old_path = String::new();
 267             if cfg!(windows) {
 268                 _old_path = os::getenv("PATH").unwrap_or(_old_path);
 269                 let mut new_path = sess.host_filesearch(PathKind::All).get_dylib_search_paths();
 270                 new_path.extend(os::split_paths(_old_path[]).into_iter());
 271                 os::setenv("PATH", os::join_paths(new_path[]).unwrap());
 272             }
 273             let cfg = syntax::ext::expand::ExpansionConfig {
 274                 crate_name: crate_name.to_string(),
 275                 enable_quotes: sess.features.borrow().quote,
 276                 recursion_limit: sess.recursion_limit.get(),
 277             };
 278             let ret = syntax::ext::expand::expand_crate(&sess.parse_sess,
 279                                               cfg,
 280                                               macros,
 281                                               syntax_exts,
 282                                               krate);
 283             if cfg!(windows) {
 284                 os::setenv("PATH", _old_path);
 285             }
 286             ret
 287         }
 288     );
 289
 290     // Needs to go *after* expansion to be able to check the results of macro expansion.
 291     time(time_passes, "complete gated feature checking", (), |_| {
 292         syntax::feature_gate::check_crate(sess.codemap(),
 293                                           &sess.parse_sess.span_diagnostic,
 294                                           &krate);
 295         sess.abort_if_errors();
 296     });
 297
 298     // JBC: make CFG processing part of expansion to avoid this problem:
 299
 300     // strip again, in case expansion added anything with a #[cfg].
 301     krate = time(time_passes, "configuration 2", krate, |krate|
 302                  syntax::config::strip_unconfigured_items(sess.diagnostic(), krate));
 303
 304     krate = time(time_passes, "maybe building test harness", krate, |krate|
 305                  syntax::test::modify_for_testing(&sess.parse_sess,
 306                                                   &sess.opts.cfg,
 307                                                   krate,
 308                                                   sess.diagnostic()));
 309
 310     krate = time(time_passes, "prelude injection", krate, |krate|
 311                  syntax::std_inject::maybe_inject_prelude(krate));
 312
 313     time(time_passes, "checking that all macro invocations are gone", &krate, |krate|
 314          syntax::ext::expand::check_for_macros(&sess.parse_sess, krate));
 315
 316     Some(krate)
 317 }
 318
 319 pub fn assign_node_ids_and_map<'ast>(sess: &Session,
 320                                      forest: &'ast mut ast_map::Forest)
 321                                      -> ast_map::Map<'ast> {
 322     struct NodeIdAssigner<'a> {
 323         sess: &'a Session
 324     }
 325
 326     impl<'a> ast_map::FoldOps for NodeIdAssigner<'a> {
 327         fn new_id(&self, old_id: ast::NodeId) -> ast::NodeId {
 328             assert_eq!(old_id, ast::DUMMY_NODE_ID);
 329             self.sess.next_node_id()
 330         }
 331     }
 332
 333     let map = time(sess.time_passes(), "assigning node ids and indexing ast", forest, |forest|
 334                    ast_map::map_crate(forest, NodeIdAssigner { sess: sess }));
 335
 336     if sess.opts.debugging_opts & config::AST_JSON != 0 {
 337         println!("{}", json::as_json(map.krate()));
 338     }
 339
 340     map
 341 }
 342
 343 /// Run the resolution, typechecking, region checking and other
 344 /// miscellaneous analysis passes on the crate. Return various
 345 /// structures carrying the results of the analysis.
 346 pub fn phase_3_run_analysis_passes<'tcx>(sess: Session,
 347                                          ast_map: ast_map::Map<'tcx>,
 348                                          arenas: &'tcx ty::CtxtArenas<'tcx>,
 349                                          name: String) -> ty::CrateAnalysis<'tcx> {
 350     let time_passes = sess.time_passes();
 351     let krate = ast_map.krate();
 352
 353     time(time_passes, "external crate/lib resolution", (), |_|
 354          creader::read_crates(&sess, krate));
 355
 356     let lang_items = time(time_passes, "language item collection", (), |_|
 357                           middle::lang_items::collect_language_items(krate, &sess));
 358
 359     let make_glob_map = if save_analysis(&sess) {
 360         resolve::MakeGlobMap::Yes
 361     } else {
 362         resolve::MakeGlobMap::No
 363     };
 364     let resolve::CrateMap {
 365         def_map,
 366         freevars,
 367         capture_mode_map,
 368         export_map,
 369         trait_map,
 370         external_exports,
 371         last_private_map,
 372         glob_map,
 373     } =
 374         time(time_passes, "resolution", (),
 375              |_| resolve::resolve_crate(&sess,
 376                                         &ast_map,
 377                                         &lang_items,
 378                                         krate,
 379                                         make_glob_map));
 380
 381     // Discard MTWT tables that aren't required past resolution.
 382     syntax::ext::mtwt::clear_tables();
 383
 384     let named_region_map = time(time_passes, "lifetime resolution", (),
 385                                 |_| middle::resolve_lifetime::krate(&sess, krate, &def_map));
 386
 387     time(time_passes, "looking for entry point", (),
 388          |_| middle::entry::find_entry_point(&sess, &ast_map));
 389
 390     sess.plugin_registrar_fn.set(
 391         time(time_passes, "looking for plugin registrar", (), |_|
 392             plugin::build::find_plugin_registrar(
 393                 sess.diagnostic(), krate)));
 394
 395     let region_map = time(time_passes, "region resolution", (), |_|
 396                           middle::region::resolve_crate(&sess, krate));
 397
 398     time(time_passes, "loop checking", (), |_|
 399          middle::check_loop::check_crate(&sess, krate));
 400
 401     let stability_index = time(time_passes, "stability index", (), |_|
 402                                stability::Index::build(krate));
 403
 404     time(time_passes, "static item recursion checking", (), |_|
 405          middle::check_static_recursion::check_crate(&sess, krate, &def_map, &ast_map));
 406
 407     let ty_cx = ty::mk_ctxt(sess,
 408                             arenas,
 409                             def_map,
 410                             named_region_map,
 411                             ast_map,
 412                             freevars,
 413                             capture_mode_map,
 414                             region_map,
 415                             lang_items,
 416                             stability_index);
 417
 418     // passes are timed inside typeck
 419     typeck::check_crate(&ty_cx, trait_map);
 420
 421     time(time_passes, "check static items", (), |_|
 422          middle::check_static::check_crate(&ty_cx));
 423
 424     // These next two const passes can probably be merged
 425     time(time_passes, "const marking", (), |_|
 426          middle::const_eval::process_crate(&ty_cx));
 427
 428     time(time_passes, "const checking", (), |_|
 429          middle::check_const::check_crate(&ty_cx));
 430
 431     let maps = (external_exports, last_private_map);
 432     let (exported_items, public_items) =
 433             time(time_passes, "privacy checking", maps, |(a, b)|
 434                  middle::privacy::check_crate(&ty_cx, &export_map, a, b));
 435
 436     time(time_passes, "intrinsic checking", (), |_|
 437          middle::intrinsicck::check_crate(&ty_cx));
 438
 439     time(time_passes, "effect checking", (), |_|
 440          middle::effect::check_crate(&ty_cx));
 441
 442     time(time_passes, "match checking", (), |_|
 443          middle::check_match::check_crate(&ty_cx));
 444
 445     time(time_passes, "liveness checking", (), |_|
 446          middle::liveness::check_crate(&ty_cx));
 447
 448     time(time_passes, "borrow checking", (), |_|
 449          borrowck::check_crate(&ty_cx));
 450
 451     time(time_passes, "rvalue checking", (), |_|
 452          middle::check_rvalues::check_crate(&ty_cx, krate));
 453
 454     // Avoid overwhelming user with errors if type checking failed.
 455     // I'm not sure how helpful this is, to be honest, but it avoids a
 456     // lot of annoying errors in the compile-fail tests (basically,
 457     // lint warnings and so on -- kindck used to do this abort, but
 458     // kindck is gone now). -nmatsakis
 459     ty_cx.sess.abort_if_errors();
 460
 461     let reachable_map =
 462         time(time_passes, "reachability checking", (), |_|
 463              reachable::find_reachable(&ty_cx, &exported_items));
 464
 465     time(time_passes, "death checking", (), |_| {
 466         middle::dead::check_crate(&ty_cx,
 467                                   &exported_items,
 468                                   &reachable_map)
 469     });
 470
 471     time(time_passes, "lint checking", (), |_|
 472          lint::check_crate(&ty_cx, &exported_items));
 473
 474     ty::CrateAnalysis {
 475         export_map: export_map,
 476         ty_cx: ty_cx,
 477         exported_items: exported_items,
 478         public_items: public_items,
 479         reachable: reachable_map,
 480         name: name,
 481         glob_map: glob_map,
 482     }
 483 }
 484
 485 fn save_analysis(sess: &Session) -> bool {
 486     (sess.opts.debugging_opts & config::SAVE_ANALYSIS) != 0
 487 }
 488
 489 pub fn phase_save_analysis(sess: &Session,
 490                            krate: &ast::Crate,
 491                            analysis: &ty::CrateAnalysis,
 492                            odir: &Option<Path>) {
 493     if !save_analysis(sess) {
 494         return;
 495     }
 496     time(sess.time_passes(), "save analysis", krate, |krate|
 497          save::process_crate(sess, krate, analysis, odir));
 498 }
 499
 500 /// Run the translation phase to LLVM, after which the AST and analysis can
 501 /// be discarded.
 502 pub fn phase_4_translate_to_llvm<'tcx>(analysis: ty::CrateAnalysis<'tcx>)
 503                                        -> (ty::ctxt<'tcx>, trans::CrateTranslation) {
 504     let time_passes = analysis.ty_cx.sess.time_passes();
 505
 506     time(time_passes, "resolving dependency formats", (), |_|
 507          dependency_format::calculate(&analysis.ty_cx));
 508
 509     // Option dance to work around the lack of stack once closures.
 510     time(time_passes, "translation", analysis, |analysis|
 511          trans::trans_crate(analysis))
 512 }
 513
 514 /// Run LLVM itself, producing a bitcode file, assembly file or object file
 515 /// as a side effect.
 516 pub fn phase_5_run_llvm_passes(sess: &Session,
 517                                trans: &trans::CrateTranslation,
 518                                outputs: &OutputFilenames) {
 519     if sess.opts.cg.no_integrated_as {
 520         let output_type = config::OutputTypeAssembly;
 521
 522         time(sess.time_passes(), "LLVM passes", (), |_|
 523             write::run_passes(sess, trans, &[output_type], outputs));
 524
 525         write::run_assembler(sess, outputs);
 526
 527         // Remove assembly source, unless --save-temps was specified
 528         if !sess.opts.cg.save_temps {
 529             fs::unlink(&outputs.temp_path(config::OutputTypeAssembly)).unwrap();
 530         }
 531     } else {
 532         time(sess.time_passes(), "LLVM passes", (), |_|
 533             write::run_passes(sess,
 534                               trans,
 535                               sess.opts.output_types[],
 536                               outputs));
 537     }
 538
 539     sess.abort_if_errors();
 540 }
 541
 542 /// Run the linker on any artifacts that resulted from the LLVM run.
 543 /// This should produce either a finished executable or library.
 544 pub fn phase_6_link_output(sess: &Session,
 545                            trans: &trans::CrateTranslation,
 546                            outputs: &OutputFilenames) {
 547     let old_path = os::getenv("PATH").unwrap_or_else(||String::new());
 548     let mut new_path = sess.host_filesearch(PathKind::All).get_tools_search_paths();
 549     new_path.extend(os::split_paths(old_path[]).into_iter());
 550     os::setenv("PATH", os::join_paths(new_path[]).unwrap());
 551
 552     time(sess.time_passes(), "linking", (), |_|
 553          link::link_binary(sess,
 554                            trans,
 555                            outputs,
 556                            trans.link.crate_name[]));
 557
 558     os::setenv("PATH", old_path);
 559 }
 560
 561 pub fn stop_after_phase_3(sess: &Session) -> bool {
 562    if sess.opts.no_trans {
 563         debug!("invoked with --no-trans, returning early from compile_input");
 564         return true;
 565     }
 566     return false;
 567 }
 568
 569 pub fn stop_after_phase_1(sess: &Session) -> bool {
 570     if sess.opts.parse_only {
 571         debug!("invoked with --parse-only, returning early from compile_input");
 572         return true;
 573     }
 574     if sess.opts.show_span.is_some() {
 575         return true;
 576     }
 577     return sess.opts.debugging_opts & config::AST_JSON_NOEXPAND != 0;
 578 }
 579
 580 pub fn stop_after_phase_2(sess: &Session) -> bool {
 581     if sess.opts.no_analysis {
 582         debug!("invoked with --no-analysis, returning early from compile_input");
 583         return true;
 584     }
 585     return sess.opts.debugging_opts & config::AST_JSON != 0;
 586 }
 587
 588 pub fn stop_after_phase_5(sess: &Session) -> bool {
 589     if !sess.opts.output_types.iter().any(|&i| i == config::OutputTypeExe) {
 590         debug!("not building executable, returning early from compile_input");
 591         return true;
 592     }
 593     return false;
 594 }
 595
 596 fn escape_dep_filename(filename: &str) -> String {
 597     // Apparently clang and gcc *only* escape spaces:
 598     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
 599     filename.replace(" ", "\\ ")
 600 }
 601
 602 fn write_out_deps(sess: &Session,
 603                   input: &Input,
 604                   outputs: &OutputFilenames,
 605                   id: &str) {
 606
 607     let mut out_filenames = Vec::new();
 608     for output_type in sess.opts.output_types.iter() {
 609         let file = outputs.path(*output_type);
 610         match *output_type {
 611             config::OutputTypeExe => {
 612                 for output in sess.crate_types.borrow().iter() {
 613                     let p = link::filename_for_input(sess, *output,
 614                                                      id, &file);
 615                     out_filenames.push(p);
 616                 }
 617             }
 618             _ => { out_filenames.push(file); }
 619         }
 620     }
 621
 622     // Write out dependency rules to the dep-info file if requested with
 623     // --dep-info
 624     let deps_filename = match sess.opts.write_dependency_info {
 625         // Use filename from --dep-file argument if given
 626         (true, Some(ref filename)) => filename.clone(),
 627         // Use default filename: crate source filename with extension replaced
 628         // by ".d"
 629         (true, None) => match *input {
 630             Input::File(..) => outputs.with_extension("d"),
 631             Input::Str(..) => {
 632                 sess.warn("can not write --dep-info without a filename \
 633                            when compiling stdin.");
 634                 return
 635             },
 636         },
 637         _ => return,
 638     };
 639
 640     let result = (|&:| -> io::IoResult<()> {
 641         // Build a list of files used to compile the output and
 642         // write Makefile-compatible dependency rules
 643         let files: Vec<String> = sess.codemap().files.borrow()
 644                                    .iter().filter(|fmap| fmap.is_real_file())
 645                                    .map(|fmap| escape_dep_filename(fmap.name[]))
 646                                    .collect();
 647         let mut file = try!(io::File::create(&deps_filename));
 648         for path in out_filenames.iter() {
 649             try!(write!(&mut file as &mut Writer,
 650                           "{}: {}\n\n", path.display(), files.connect(" ")));
 651         }
 652         Ok(())
 653     })();
 654
 655     match result {
 656         Ok(()) => {}
 657         Err(e) => {
 658             sess.fatal(format!("error writing dependencies to `{}`: {}",
 659                                deps_filename.display(), e)[]);
 660         }
 661     }
 662 }
 663
 664 pub fn collect_crate_types(session: &Session,
 665                            attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
 666     // Unconditionally collect crate types from attributes to make them used
 667     let attr_types: Vec<config::CrateType> = attrs.iter().filter_map(|a| {
 668         if a.check_name("crate_type") {
 669             match a.value_str() {
 670                 Some(ref n) if *n == "rlib" => {
 671                     Some(config::CrateTypeRlib)
 672                 }
 673                 Some(ref n) if *n == "dylib" => {
 674                     Some(config::CrateTypeDylib)
 675                 }
 676                 Some(ref n) if *n == "lib" => {
 677                     Some(config::default_lib_output())
 678                 }
 679                 Some(ref n) if *n == "staticlib" => {
 680                     Some(config::CrateTypeStaticlib)
 681                 }
 682                 Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
 683                 Some(_) => {
 684                     session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
 685                                      ast::CRATE_NODE_ID,
 686                                      a.span,
 687                                      "invalid `crate_type` \
 688                                       value".to_string());
 689                     None
 690                 }
 691                 _ => {
 692                     session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
 693                                      ast::CRATE_NODE_ID,
 694                                      a.span,
 695                                      "`crate_type` requires a \
 696                                       value".to_string());
 697                     None
 698                 }
 699             }
 700         } else {
 701             None
 702         }
 703     }).collect();
 704
 705     // If we're generating a test executable, then ignore all other output
 706     // styles at all other locations
 707     if session.opts.test {
 708         return vec!(config::CrateTypeExecutable)
 709     }
 710
 711     // Only check command line flags if present. If no types are specified by
 712     // command line, then reuse the empty `base` Vec to hold the types that
 713     // will be found in crate attributes.
 714     let mut base = session.opts.crate_types.clone();
 715     if base.len() == 0 {
 716         base.extend(attr_types.into_iter());
 717         if base.len() == 0 {
 718             base.push(link::default_output_for_target(session));
 719         }
 720         base.sort();
 721         base.dedup();
 722     }
 723
 724     base.into_iter().filter(|crate_type| {
 725         let res = !link::invalid_output_for_target(session, *crate_type);
 726
 727         if !res {
 728             session.warn(format!("dropping unsupported crate type `{}` \
 729                                    for target `{}`",
 730                                  *crate_type, session.opts.target_triple)[]);
 731         }
 732
 733         res
 734     }).collect()
 735 }
 736
 737 pub fn collect_crate_metadata(session: &Session,
 738                               _attrs: &[ast::Attribute]) -> Vec<String> {
 739     session.opts.cg.metadata.clone()
 740 }
 741
 742 pub fn build_output_filenames(input: &Input,
 743                               odir: &Option<Path>,
 744                               ofile: &Option<Path>,
 745                               attrs: &[ast::Attribute],
 746                               sess: &Session)
 747                            -> OutputFilenames {
 748     match *ofile {
 749         None => {
 750             // "-" as input file will cause the parser to read from stdin so we
 751             // have to make up a name
 752             // We want to toss everything after the final '.'
 753             let dirpath = match *odir {
 754                 Some(ref d) => d.clone(),
 755                 None => Path::new(".")
 756             };
 757
 758             // If a crate name is present, we use it as the link name
 759             let stem = sess.opts.crate_name.clone().or_else(|| {
 760                 attr::find_crate_name(attrs).map(|n| n.get().to_string())
 761             }).unwrap_or(input.filestem());
 762
 763             OutputFilenames {
 764                 out_directory: dirpath,
 765                 out_filestem: stem,
 766                 single_output_file: None,
 767                 extra: sess.opts.cg.extra_filename.clone(),
 768             }
 769         }
 770
 771         Some(ref out_file) => {
 772             let ofile = if sess.opts.output_types.len() > 1 {
 773                 sess.warn("ignoring specified output filename because multiple \
 774                            outputs were requested");
 775                 None
 776             } else {
 777                 Some(out_file.clone())
 778             };
 779             if *odir != None {
 780                 sess.warn("ignoring --out-dir flag due to -o flag.");
 781             }
 782             OutputFilenames {
 783                 out_directory: out_file.dir_path(),
 784                 out_filestem: out_file.filestem_str().unwrap().to_string(),
 785                 single_output_file: ofile,
 786                 extra: sess.opts.cg.extra_filename.clone(),
 787             }
 788         }
 789     }
 790 }