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