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 sess.show_span() {
 150         syntax::show_span::run(sess.diagnostic(), &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                 deriving_hash_type_parameter: sess.features.borrow().default_type_params,
 276                 enable_quotes: sess.features.borrow().quote,
 277                 recursion_limit: sess.recursion_limit.get(),
 278             };
 279             let ret = syntax::ext::expand::expand_crate(&sess.parse_sess,
 280                                               cfg,
 281                                               macros,
 282                                               syntax_exts,
 283                                               krate);
 284             if cfg!(windows) {
 285                 os::setenv("PATH", _old_path);
 286             }
 287             ret
 288         }
 289     );
 290
 291     // Needs to go *after* expansion to be able to check the results of macro expansion.
 292     time(time_passes, "complete gated feature checking", (), |_| {
 293         syntax::feature_gate::check_crate(sess.codemap(),
 294                                           &sess.parse_sess.span_diagnostic,
 295                                           &krate);
 296         sess.abort_if_errors();
 297     });
 298
 299     // JBC: make CFG processing part of expansion to avoid this problem:
 300
 301     // strip again, in case expansion added anything with a #[cfg].
 302     krate = time(time_passes, "configuration 2", krate, |krate|
 303                  syntax::config::strip_unconfigured_items(sess.diagnostic(), krate));
 304
 305     krate = time(time_passes, "maybe building test harness", krate, |krate|
 306                  syntax::test::modify_for_testing(&sess.parse_sess,
 307                                                   &sess.opts.cfg,
 308                                                   krate,
 309                                                   sess.diagnostic()));
 310
 311     krate = time(time_passes, "prelude injection", krate, |krate|
 312                  syntax::std_inject::maybe_inject_prelude(krate));
 313
 314     time(time_passes, "checking that all macro invocations are gone", &krate, |krate|
 315          syntax::ext::expand::check_for_macros(&sess.parse_sess, krate));
 316
 317     Some(krate)
 318 }
 319
 320 pub fn assign_node_ids_and_map<'ast>(sess: &Session,
 321                                      forest: &'ast mut ast_map::Forest)
 322                                      -> ast_map::Map<'ast> {
 323     struct NodeIdAssigner<'a> {
 324         sess: &'a Session
 325     }
 326
 327     impl<'a> ast_map::FoldOps for NodeIdAssigner<'a> {
 328         fn new_id(&self, old_id: ast::NodeId) -> ast::NodeId {
 329             assert_eq!(old_id, ast::DUMMY_NODE_ID);
 330             self.sess.next_node_id()
 331         }
 332     }
 333
 334     let map = time(sess.time_passes(), "assigning node ids and indexing ast", forest, |forest|
 335                    ast_map::map_crate(forest, NodeIdAssigner { sess: sess }));
 336
 337     if sess.opts.debugging_opts & config::AST_JSON != 0 {
 338         println!("{}", json::as_json(map.krate()));
 339     }
 340
 341     map
 342 }
 343
 344 /// Run the resolution, typechecking, region checking and other
 345 /// miscellaneous analysis passes on the crate. Return various
 346 /// structures carrying the results of the analysis.
 347 pub fn phase_3_run_analysis_passes<'tcx>(sess: Session,
 348                                          ast_map: ast_map::Map<'tcx>,
 349                                          arenas: &'tcx ty::CtxtArenas<'tcx>,
 350                                          name: String) -> ty::CrateAnalysis<'tcx> {
 351     let time_passes = sess.time_passes();
 352     let krate = ast_map.krate();
 353
 354     time(time_passes, "external crate/lib resolution", (), |_|
 355          creader::read_crates(&sess, krate));
 356
 357     let lang_items = time(time_passes, "language item collection", (), |_|
 358                           middle::lang_items::collect_language_items(krate, &sess));
 359
 360     let make_glob_map = if save_analysis(&sess) {
 361         resolve::MakeGlobMap::Yes
 362     } else {
 363         resolve::MakeGlobMap::No
 364     };
 365     let resolve::CrateMap {
 366         def_map,
 367         freevars,
 368         capture_mode_map,
 369         export_map,
 370         trait_map,
 371         external_exports,
 372         last_private_map,
 373         glob_map,
 374     } =
 375         time(time_passes, "resolution", (),
 376              |_| resolve::resolve_crate(&sess,
 377                                         &ast_map,
 378                                         &lang_items,
 379                                         krate,
 380                                         make_glob_map));
 381
 382     // Discard MTWT tables that aren't required past resolution.
 383     syntax::ext::mtwt::clear_tables();
 384
 385     let named_region_map = time(time_passes, "lifetime resolution", (),
 386                                 |_| middle::resolve_lifetime::krate(&sess, krate, &def_map));
 387
 388     time(time_passes, "looking for entry point", (),
 389          |_| middle::entry::find_entry_point(&sess, &ast_map));
 390
 391     sess.plugin_registrar_fn.set(
 392         time(time_passes, "looking for plugin registrar", (), |_|
 393             plugin::build::find_plugin_registrar(
 394                 sess.diagnostic(), krate)));
 395
 396     let region_map = time(time_passes, "region resolution", (), |_|
 397                           middle::region::resolve_crate(&sess, krate));
 398
 399     time(time_passes, "loop checking", (), |_|
 400          middle::check_loop::check_crate(&sess, krate));
 401
 402     let stability_index = time(time_passes, "stability index", (), |_|
 403                                stability::Index::build(krate));
 404
 405     time(time_passes, "static item recursion checking", (), |_|
 406          middle::check_static_recursion::check_crate(&sess, krate, &def_map, &ast_map));
 407
 408     let ty_cx = ty::mk_ctxt(sess,
 409                             arenas,
 410                             def_map,
 411                             named_region_map,
 412                             ast_map,
 413                             freevars,
 414                             capture_mode_map,
 415                             region_map,
 416                             lang_items,
 417                             stability_index);
 418
 419     // passes are timed inside typeck
 420     typeck::check_crate(&ty_cx, trait_map);
 421
 422     time(time_passes, "check static items", (), |_|
 423          middle::check_static::check_crate(&ty_cx));
 424
 425     // These next two const passes can probably be merged
 426     time(time_passes, "const marking", (), |_|
 427          middle::const_eval::process_crate(&ty_cx));
 428
 429     time(time_passes, "const checking", (), |_|
 430          middle::check_const::check_crate(&ty_cx));
 431
 432     let maps = (external_exports, last_private_map);
 433     let (exported_items, public_items) =
 434             time(time_passes, "privacy checking", maps, |(a, b)|
 435                  middle::privacy::check_crate(&ty_cx, &export_map, a, b));
 436
 437     time(time_passes, "intrinsic checking", (), |_|
 438          middle::intrinsicck::check_crate(&ty_cx));
 439
 440     time(time_passes, "effect checking", (), |_|
 441          middle::effect::check_crate(&ty_cx));
 442
 443     time(time_passes, "match checking", (), |_|
 444          middle::check_match::check_crate(&ty_cx));
 445
 446     time(time_passes, "liveness checking", (), |_|
 447          middle::liveness::check_crate(&ty_cx));
 448
 449     time(time_passes, "borrow checking", (), |_|
 450          borrowck::check_crate(&ty_cx));
 451
 452     time(time_passes, "rvalue checking", (), |_|
 453          middle::check_rvalues::check_crate(&ty_cx, krate));
 454
 455     // Avoid overwhelming user with errors if type checking failed.
 456     // I'm not sure how helpful this is, to be honest, but it avoids a
 457     // lot of annoying errors in the compile-fail tests (basically,
 458     // lint warnings and so on -- kindck used to do this abort, but
 459     // kindck is gone now). -nmatsakis
 460     ty_cx.sess.abort_if_errors();
 461
 462     let reachable_map =
 463         time(time_passes, "reachability checking", (), |_|
 464              reachable::find_reachable(&ty_cx, &exported_items));
 465
 466     time(time_passes, "death checking", (), |_| {
 467         middle::dead::check_crate(&ty_cx,
 468                                   &exported_items,
 469                                   &reachable_map)
 470     });
 471
 472     time(time_passes, "lint checking", (), |_|
 473          lint::check_crate(&ty_cx, &exported_items));
 474
 475     ty::CrateAnalysis {
 476         export_map: export_map,
 477         ty_cx: ty_cx,
 478         exported_items: exported_items,
 479         public_items: public_items,
 480         reachable: reachable_map,
 481         name: name,
 482         glob_map: glob_map,
 483     }
 484 }
 485
 486 fn save_analysis(sess: &Session) -> bool {
 487     (sess.opts.debugging_opts & config::SAVE_ANALYSIS) != 0
 488 }
 489
 490 pub fn phase_save_analysis(sess: &Session,
 491                            krate: &ast::Crate,
 492                            analysis: &ty::CrateAnalysis,
 493                            odir: &Option<Path>) {
 494     if !save_analysis(sess) {
 495         return;
 496     }
 497     time(sess.time_passes(), "save analysis", krate, |krate|
 498          save::process_crate(sess, krate, analysis, odir));
 499 }
 500
 501 /// Run the translation phase to LLVM, after which the AST and analysis can
 502 /// be discarded.
 503 pub fn phase_4_translate_to_llvm<'tcx>(analysis: ty::CrateAnalysis<'tcx>)
 504                                        -> (ty::ctxt<'tcx>, trans::CrateTranslation) {
 505     let time_passes = analysis.ty_cx.sess.time_passes();
 506
 507     time(time_passes, "resolving dependency formats", (), |_|
 508          dependency_format::calculate(&analysis.ty_cx));
 509
 510     // Option dance to work around the lack of stack once closures.
 511     time(time_passes, "translation", analysis, |analysis|
 512          trans::trans_crate(analysis))
 513 }
 514
 515 /// Run LLVM itself, producing a bitcode file, assembly file or object file
 516 /// as a side effect.
 517 pub fn phase_5_run_llvm_passes(sess: &Session,
 518                                trans: &trans::CrateTranslation,
 519                                outputs: &OutputFilenames) {
 520     if sess.opts.cg.no_integrated_as {
 521         let output_type = config::OutputTypeAssembly;
 522
 523         time(sess.time_passes(), "LLVM passes", (), |_|
 524             write::run_passes(sess, trans, &[output_type], outputs));
 525
 526         write::run_assembler(sess, outputs);
 527
 528         // Remove assembly source, unless --save-temps was specified
 529         if !sess.opts.cg.save_temps {
 530             fs::unlink(&outputs.temp_path(config::OutputTypeAssembly)).unwrap();
 531         }
 532     } else {
 533         time(sess.time_passes(), "LLVM passes", (), |_|
 534             write::run_passes(sess,
 535                               trans,
 536                               sess.opts.output_types[],
 537                               outputs));
 538     }
 539
 540     sess.abort_if_errors();
 541 }
 542
 543 /// Run the linker on any artifacts that resulted from the LLVM run.
 544 /// This should produce either a finished executable or library.
 545 pub fn phase_6_link_output(sess: &Session,
 546                            trans: &trans::CrateTranslation,
 547                            outputs: &OutputFilenames) {
 548     let old_path = os::getenv("PATH").unwrap_or_else(||String::new());
 549     let mut new_path = sess.host_filesearch(PathKind::All).get_tools_search_paths();
 550     new_path.extend(os::split_paths(old_path[]).into_iter());
 551     os::setenv("PATH", os::join_paths(new_path[]).unwrap());
 552
 553     time(sess.time_passes(), "linking", (), |_|
 554          link::link_binary(sess,
 555                            trans,
 556                            outputs,
 557                            trans.link.crate_name[]));
 558
 559     os::setenv("PATH", old_path);
 560 }
 561
 562 pub fn stop_after_phase_3(sess: &Session) -> bool {
 563    if sess.opts.no_trans {
 564         debug!("invoked with --no-trans, returning early from compile_input");
 565         return true;
 566     }
 567     return false;
 568 }
 569
 570 pub fn stop_after_phase_1(sess: &Session) -> bool {
 571     if sess.opts.parse_only {
 572         debug!("invoked with --parse-only, returning early from compile_input");
 573         return true;
 574     }
 575     if sess.show_span() {
 576         return true;
 577     }
 578     return sess.opts.debugging_opts & config::AST_JSON_NOEXPAND != 0;
 579 }
 580
 581 pub fn stop_after_phase_2(sess: &Session) -> bool {
 582     if sess.opts.no_analysis {
 583         debug!("invoked with --no-analysis, returning early from compile_input");
 584         return true;
 585     }
 586     return sess.opts.debugging_opts & config::AST_JSON != 0;
 587 }
 588
 589 pub fn stop_after_phase_5(sess: &Session) -> bool {
 590     if !sess.opts.output_types.iter().any(|&i| i == config::OutputTypeExe) {
 591         debug!("not building executable, returning early from compile_input");
 592         return true;
 593     }
 594     return false;
 595 }
 596
 597 fn escape_dep_filename(filename: &str) -> String {
 598     // Apparently clang and gcc *only* escape spaces:
 599     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
 600     filename.replace(" ", "\\ ")
 601 }
 602
 603 fn write_out_deps(sess: &Session,
 604                   input: &Input,
 605                   outputs: &OutputFilenames,
 606                   id: &str) {
 607
 608     let mut out_filenames = Vec::new();
 609     for output_type in sess.opts.output_types.iter() {
 610         let file = outputs.path(*output_type);
 611         match *output_type {
 612             config::OutputTypeExe => {
 613                 for output in sess.crate_types.borrow().iter() {
 614                     let p = link::filename_for_input(sess, *output,
 615                                                      id, &file);
 616                     out_filenames.push(p);
 617                 }
 618             }
 619             _ => { out_filenames.push(file); }
 620         }
 621     }
 622
 623     // Write out dependency rules to the dep-info file if requested with
 624     // --dep-info
 625     let deps_filename = match sess.opts.write_dependency_info {
 626         // Use filename from --dep-file argument if given
 627         (true, Some(ref filename)) => filename.clone(),
 628         // Use default filename: crate source filename with extension replaced
 629         // by ".d"
 630         (true, None) => match *input {
 631             Input::File(..) => outputs.with_extension("d"),
 632             Input::Str(..) => {
 633                 sess.warn("can not write --dep-info without a filename \
 634                            when compiling stdin.");
 635                 return
 636             },
 637         },
 638         _ => return,
 639     };
 640
 641     let result = (|| -> io::IoResult<()> {
 642         // Build a list of files used to compile the output and
 643         // write Makefile-compatible dependency rules
 644         let files: Vec<String> = sess.codemap().files.borrow()
 645                                    .iter().filter(|fmap| fmap.is_real_file())
 646                                    .map(|fmap| escape_dep_filename(fmap.name[]))
 647                                    .collect();
 648         let mut file = try!(io::File::create(&deps_filename));
 649         for path in out_filenames.iter() {
 650             try!(write!(&mut file as &mut Writer,
 651                           "{}: {}\n\n", path.display(), files.connect(" ")));
 652         }
 653         Ok(())
 654     })();
 655
 656     match result {
 657         Ok(()) => {}
 658         Err(e) => {
 659             sess.fatal(format!("error writing dependencies to `{}`: {}",
 660                                deps_filename.display(), e)[]);
 661         }
 662     }
 663 }
 664
 665 pub fn collect_crate_types(session: &Session,
 666                            attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
 667     // Unconditionally collect crate types from attributes to make them used
 668     let attr_types: Vec<config::CrateType> = attrs.iter().filter_map(|a| {
 669         if a.check_name("crate_type") {
 670             match a.value_str() {
 671                 Some(ref n) if *n == "rlib" => {
 672                     Some(config::CrateTypeRlib)
 673                 }
 674                 Some(ref n) if *n == "dylib" => {
 675                     Some(config::CrateTypeDylib)
 676                 }
 677                 Some(ref n) if *n == "lib" => {
 678                     Some(config::default_lib_output())
 679                 }
 680                 Some(ref n) if *n == "staticlib" => {
 681                     Some(config::CrateTypeStaticlib)
 682                 }
 683                 Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
 684                 Some(_) => {
 685                     session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
 686                                      ast::CRATE_NODE_ID,
 687                                      a.span,
 688                                      "invalid `crate_type` \
 689                                       value".to_string());
 690                     None
 691                 }
 692                 _ => {
 693                     session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
 694                                      ast::CRATE_NODE_ID,
 695                                      a.span,
 696                                      "`crate_type` requires a \
 697                                       value".to_string());
 698                     None
 699                 }
 700             }
 701         } else {
 702             None
 703         }
 704     }).collect();
 705
 706     // If we're generating a test executable, then ignore all other output
 707     // styles at all other locations
 708     if session.opts.test {
 709         return vec!(config::CrateTypeExecutable)
 710     }
 711
 712     // Only check command line flags if present. If no types are specified by
 713     // command line, then reuse the empty `base` Vec to hold the types that
 714     // will be found in crate attributes.
 715     let mut base = session.opts.crate_types.clone();
 716     if base.len() == 0 {
 717         base.extend(attr_types.into_iter());
 718         if base.len() == 0 {
 719             base.push(link::default_output_for_target(session));
 720         }
 721         base.sort();
 722         base.dedup();
 723     }
 724
 725     base.into_iter().filter(|crate_type| {
 726         let res = !link::invalid_output_for_target(session, *crate_type);
 727
 728         if !res {
 729             session.warn(format!("dropping unsupported crate type `{}` \
 730                                    for target `{}`",
 731                                  *crate_type, session.opts.target_triple)[]);
 732         }
 733
 734         res
 735     }).collect()
 736 }
 737
 738 pub fn collect_crate_metadata(session: &Session,
 739                               _attrs: &[ast::Attribute]) -> Vec<String> {
 740     session.opts.cg.metadata.clone()
 741 }
 742
 743 pub fn build_output_filenames(input: &Input,
 744                               odir: &Option<Path>,
 745                               ofile: &Option<Path>,
 746                               attrs: &[ast::Attribute],
 747                               sess: &Session)
 748                            -> OutputFilenames {
 749     match *ofile {
 750         None => {
 751             // "-" as input file will cause the parser to read from stdin so we
 752             // have to make up a name
 753             // We want to toss everything after the final '.'
 754             let dirpath = match *odir {
 755                 Some(ref d) => d.clone(),
 756                 None => Path::new(".")
 757             };
 758
 759             // If a crate name is present, we use it as the link name
 760             let stem = sess.opts.crate_name.clone().or_else(|| {
 761                 attr::find_crate_name(attrs).map(|n| n.get().to_string())
 762             }).unwrap_or(input.filestem());
 763
 764             OutputFilenames {
 765                 out_directory: dirpath,
 766                 out_filestem: stem,
 767                 single_output_file: None,
 768                 extra: sess.opts.cg.extra_filename.clone(),
 769             }
 770         }
 771
 772         Some(ref out_file) => {
 773             let ofile = if sess.opts.output_types.len() > 1 {
 774                 sess.warn("ignoring specified output filename because multiple \
 775                            outputs were requested");
 776                 None
 777             } else {
 778                 Some(out_file.clone())
 779             };
 780             if *odir != None {
 781                 sess.warn("ignoring --out-dir flag due to -o flag.");
 782             }
 783             OutputFilenames {
 784                 out_directory: out_file.dir_path(),
 785                 out_filestem: out_file.filestem_str().unwrap().to_string(),
 786                 single_output_file: ofile,
 787                 extra: sess.opts.cg.extra_filename.clone(),
 788             }
 789         }
 790     }
 791 }