src/librustc_driver/driver.rs

   1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use rustc::hir::{self, map as hir_map};
  12 use rustc::hir::lowering::lower_crate;
  13 use rustc::ich::Fingerprint;
  14 use rustc_data_structures::stable_hasher::StableHasher;
  15 use rustc_mir as mir;
  16 use rustc::session::{Session, CompileResult};
  17 use rustc::session::CompileIncomplete;
  18 use rustc::session::config::{self, Input, OutputFilenames, OutputType,
  19                              OutputTypes};
  20 use rustc::session::search_paths::PathKind;
  21 use rustc::lint;
  22 use rustc::middle::{self, dependency_format, stability, reachable};
  23 use rustc::middle::privacy::AccessLevels;
  24 use rustc::mir::transform::{MIR_CONST, MIR_VALIDATED, MIR_OPTIMIZED, Passes};
  25 use rustc::ty::{self, TyCtxt, Resolutions, GlobalArenas};
  26 use rustc::traits;
  27 use rustc::util::common::{ErrorReported, time};
  28 use rustc::util::nodemap::NodeSet;
  29 use rustc::util::fs::rename_or_copy_remove;
  30 use rustc_allocator as allocator;
  31 use rustc_borrowck as borrowck;
  32 use rustc_incremental::{self, IncrementalHashesMap};
  33 use rustc_resolve::{MakeGlobMap, Resolver};
  34 use rustc_metadata::creader::CrateLoader;
  35 use rustc_metadata::cstore::{self, CStore};
  36 use rustc_trans::back::{link, write};
  37 use rustc_trans as trans;
  38 use rustc_typeck as typeck;
  39 use rustc_privacy;
  40 use rustc_plugin::registry::Registry;
  41 use rustc_plugin as plugin;
  42 use rustc_passes::{ast_validation, no_asm, loops, consts, static_recursion, hir_stats};
  43 use rustc_const_eval::{self, check_match};
  44 use super::Compilation;
  45
  46 use serialize::json;
  47
  48 use std::env;
  49 use std::ffi::{OsString, OsStr};
  50 use std::fs;
  51 use std::io::{self, Write};
  52 use std::iter;
  53 use std::path::{Path, PathBuf};
  54 use std::rc::Rc;
  55 use syntax::{ast, diagnostics, visit};
  56 use syntax::attr;
  57 use syntax::ext::base::ExtCtxt;
  58 use syntax::parse::{self, PResult};
  59 use syntax::symbol::Symbol;
  60 use syntax::util::node_count::NodeCounter;
  61 use syntax;
  62 use syntax_ext;
  63 use arena::DroplessArena;
  64
  65 use derive_registrar;
  66
  67 pub fn compile_input(sess: &Session,
  68                      cstore: &CStore,
  69                      input: &Input,
  70                      outdir: &Option<PathBuf>,
  71                      output: &Option<PathBuf>,
  72                      addl_plugins: Option<Vec<String>>,
  73                      control: &CompileController) -> CompileResult {
  74     macro_rules! controller_entry_point {
  75         ($point: ident, $tsess: expr, $make_state: expr, $phase_result: expr) => {{
  76             let state = &mut $make_state;
  77             let phase_result: &CompileResult = &$phase_result;
  78             if phase_result.is_ok() || control.$point.run_callback_on_error {
  79                 (control.$point.callback)(state);
  80             }
  81
  82             if control.$point.stop == Compilation::Stop {
  83                 // FIXME: shouldn't this return Err(CompileIncomplete::Stopped)
  84                 // if there are no errors?
  85                 return $tsess.compile_status();
  86             }
  87         }}
  88     }
  89
  90     // We need nested scopes here, because the intermediate results can keep
  91     // large chunks of memory alive and we want to free them as soon as
  92     // possible to keep the peak memory usage low
  93     let (outputs, trans) = {
  94         let krate = match phase_1_parse_input(sess, input) {
  95             Ok(krate) => krate,
  96             Err(mut parse_error) => {
  97                 parse_error.emit();
  98                 return Err(CompileIncomplete::Errored(ErrorReported));
  99             }
 100         };
 101
 102         let (krate, registry) = {
 103             let mut compile_state = CompileState::state_after_parse(input,
 104                                                                     sess,
 105                                                                     outdir,
 106                                                                     output,
 107                                                                     krate,
 108                                                                     &cstore);
 109             controller_entry_point!(after_parse,
 110                                     sess,
 111                                     compile_state,
 112                                     Ok(()));
 113
 114             (compile_state.krate.unwrap(), compile_state.registry)
 115         };
 116
 117         let outputs = build_output_filenames(input, outdir, output, &krate.attrs, sess);
 118         let crate_name = link::find_crate_name(Some(sess), &krate.attrs, input);
 119         let ExpansionResult { expanded_crate, defs, analysis, resolutions, mut hir_forest } = {
 120             phase_2_configure_and_expand(
 121                 sess, &cstore, krate, registry, &crate_name, addl_plugins, control.make_glob_map,
 122                 |expanded_crate| {
 123                     let mut state = CompileState::state_after_expand(
 124                         input, sess, outdir, output, &cstore, expanded_crate, &crate_name,
 125                     );
 126                     controller_entry_point!(after_expand, sess, state, Ok(()));
 127                     Ok(())
 128                 }
 129             )?
 130         };
 131
 132         write_out_deps(sess, &outputs, &crate_name);
 133         if sess.opts.output_types.contains_key(&OutputType::DepInfo) &&
 134             sess.opts.output_types.keys().count() == 1 {
 135             return Ok(())
 136         }
 137
 138         let arena = DroplessArena::new();
 139         let arenas = GlobalArenas::new();
 140
 141         // Construct the HIR map
 142         let hir_map = time(sess.time_passes(),
 143                            "indexing hir",
 144                            || hir_map::map_crate(&mut hir_forest, defs));
 145
 146         {
 147             let _ignore = hir_map.dep_graph.in_ignore();
 148             controller_entry_point!(after_hir_lowering,
 149                                     sess,
 150                                     CompileState::state_after_hir_lowering(input,
 151                                                                   sess,
 152                                                                   outdir,
 153                                                                   output,
 154                                                                   &arena,
 155                                                                   &arenas,
 156                                                                   &cstore,
 157                                                                   &hir_map,
 158                                                                   &analysis,
 159                                                                   &resolutions,
 160                                                                   &expanded_crate,
 161                                                                   &hir_map.krate(),
 162                                                                   &crate_name),
 163                                     Ok(()));
 164         }
 165
 166         time(sess.time_passes(), "attribute checking", || {
 167             hir::check_attr::check_crate(sess, &expanded_crate);
 168         });
 169
 170         let opt_crate = if control.keep_ast {
 171             Some(&expanded_crate)
 172         } else {
 173             drop(expanded_crate);
 174             None
 175         };
 176
 177         phase_3_run_analysis_passes(sess,
 178                                     hir_map,
 179                                     analysis,
 180                                     resolutions,
 181                                     &arena,
 182                                     &arenas,
 183                                     &crate_name,
 184                                     |tcx, analysis, incremental_hashes_map, result| {
 185             {
 186                 // Eventually, we will want to track plugins.
 187                 let _ignore = tcx.dep_graph.in_ignore();
 188
 189                 let mut state = CompileState::state_after_analysis(input,
 190                                                                    sess,
 191                                                                    outdir,
 192                                                                    output,
 193                                                                    opt_crate,
 194                                                                    tcx.hir.krate(),
 195                                                                    &analysis,
 196                                                                    tcx,
 197                                                                    &crate_name);
 198                 (control.after_analysis.callback)(&mut state);
 199
 200                 if control.after_analysis.stop == Compilation::Stop {
 201                     return result.and_then(|_| Err(CompileIncomplete::Stopped));
 202                 }
 203             }
 204
 205             result?;
 206
 207             if log_enabled!(::log::LogLevel::Info) {
 208                 println!("Pre-trans");
 209                 tcx.print_debug_stats();
 210             }
 211             let trans = phase_4_translate_to_llvm(tcx, analysis, &incremental_hashes_map,
 212                                                   &outputs);
 213
 214             if log_enabled!(::log::LogLevel::Info) {
 215                 println!("Post-trans");
 216                 tcx.print_debug_stats();
 217             }
 218
 219             if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
 220                 if let Err(e) = mir::transform::dump_mir::emit_mir(tcx, &outputs) {
 221                     sess.err(&format!("could not emit MIR: {}", e));
 222                     sess.abort_if_errors();
 223                 }
 224             }
 225
 226             Ok((outputs, trans))
 227         })??
 228     };
 229
 230     if sess.opts.debugging_opts.print_type_sizes {
 231         sess.code_stats.borrow().print_type_sizes();
 232     }
 233
 234     let phase5_result = phase_5_run_llvm_passes(sess, &trans, &outputs);
 235
 236     controller_entry_point!(after_llvm,
 237                             sess,
 238                             CompileState::state_after_llvm(input, sess, outdir, output, &trans),
 239                             phase5_result);
 240     phase5_result?;
 241
 242     write::cleanup_llvm(&trans);
 243
 244     phase_6_link_output(sess, &trans, &outputs);
 245
 246     // Now that we won't touch anything in the incremental compilation directory
 247     // any more, we can finalize it (which involves renaming it)
 248     rustc_incremental::finalize_session_directory(sess, trans.link.crate_hash);
 249
 250     if sess.opts.debugging_opts.perf_stats {
 251         sess.print_perf_stats();
 252     }
 253
 254     controller_entry_point!(compilation_done,
 255                             sess,
 256                             CompileState::state_when_compilation_done(input, sess, outdir, output),
 257                             Ok(()));
 258
 259     Ok(())
 260 }
 261
 262 fn keep_hygiene_data(sess: &Session) -> bool {
 263     sess.opts.debugging_opts.keep_hygiene_data
 264 }
 265
 266
 267 /// The name used for source code that doesn't originate in a file
 268 /// (e.g. source from stdin or a string)
 269 pub fn anon_src() -> String {
 270     "<anon>".to_string()
 271 }
 272
 273 pub fn source_name(input: &Input) -> String {
 274     match *input {
 275         // FIXME (#9639): This needs to handle non-utf8 paths
 276         Input::File(ref ifile) => ifile.to_str().unwrap().to_string(),
 277         Input::Str { ref name, .. } => name.clone(),
 278     }
 279 }
 280
 281 /// CompileController is used to customise compilation, it allows compilation to
 282 /// be stopped and/or to call arbitrary code at various points in compilation.
 283 /// It also allows for various flags to be set to influence what information gets
 284 /// collected during compilation.
 285 ///
 286 /// This is a somewhat higher level controller than a Session - the Session
 287 /// controls what happens in each phase, whereas the CompileController controls
 288 /// whether a phase is run at all and whether other code (from outside the
 289 /// the compiler) is run between phases.
 290 ///
 291 /// Note that if compilation is set to stop and a callback is provided for a
 292 /// given entry point, the callback is called before compilation is stopped.
 293 ///
 294 /// Expect more entry points to be added in the future.
 295 pub struct CompileController<'a> {
 296     pub after_parse: PhaseController<'a>,
 297     pub after_expand: PhaseController<'a>,
 298     pub after_hir_lowering: PhaseController<'a>,
 299     pub after_analysis: PhaseController<'a>,
 300     pub after_llvm: PhaseController<'a>,
 301     pub compilation_done: PhaseController<'a>,
 302
 303     pub make_glob_map: MakeGlobMap,
 304     // Whether the compiler should keep the ast beyond parsing.
 305     pub keep_ast: bool,
 306 }
 307
 308 impl<'a> CompileController<'a> {
 309     pub fn basic() -> CompileController<'a> {
 310         CompileController {
 311             after_parse: PhaseController::basic(),
 312             after_expand: PhaseController::basic(),
 313             after_hir_lowering: PhaseController::basic(),
 314             after_analysis: PhaseController::basic(),
 315             after_llvm: PhaseController::basic(),
 316             compilation_done: PhaseController::basic(),
 317             make_glob_map: MakeGlobMap::No,
 318             keep_ast: false,
 319         }
 320     }
 321 }
 322
 323 pub struct PhaseController<'a> {
 324     pub stop: Compilation,
 325     // If true then the compiler will try to run the callback even if the phase
 326     // ends with an error. Note that this is not always possible.
 327     pub run_callback_on_error: bool,
 328     pub callback: Box<Fn(&mut CompileState) + 'a>,
 329 }
 330
 331 impl<'a> PhaseController<'a> {
 332     pub fn basic() -> PhaseController<'a> {
 333         PhaseController {
 334             stop: Compilation::Continue,
 335             run_callback_on_error: false,
 336             callback: box |_| {},
 337         }
 338     }
 339 }
 340
 341 /// State that is passed to a callback. What state is available depends on when
 342 /// during compilation the callback is made. See the various constructor methods
 343 /// (`state_*`) in the impl to see which data is provided for any given entry point.
 344 pub struct CompileState<'a, 'tcx: 'a> {
 345     pub input: &'a Input,
 346     pub session: &'tcx Session,
 347     pub krate: Option<ast::Crate>,
 348     pub registry: Option<Registry<'a>>,
 349     pub cstore: Option<&'a CStore>,
 350     pub crate_name: Option<&'a str>,
 351     pub output_filenames: Option<&'a OutputFilenames>,
 352     pub out_dir: Option<&'a Path>,
 353     pub out_file: Option<&'a Path>,
 354     pub arena: Option<&'tcx DroplessArena>,
 355     pub arenas: Option<&'tcx GlobalArenas<'tcx>>,
 356     pub expanded_crate: Option<&'a ast::Crate>,
 357     pub hir_crate: Option<&'a hir::Crate>,
 358     pub hir_map: Option<&'a hir_map::Map<'tcx>>,
 359     pub resolutions: Option<&'a Resolutions>,
 360     pub analysis: Option<&'a ty::CrateAnalysis>,
 361     pub tcx: Option<TyCtxt<'a, 'tcx, 'tcx>>,
 362     pub trans: Option<&'a trans::CrateTranslation>,
 363 }
 364
 365 impl<'a, 'tcx> CompileState<'a, 'tcx> {
 366     fn empty(input: &'a Input,
 367              session: &'tcx Session,
 368              out_dir: &'a Option<PathBuf>)
 369              -> Self {
 370         CompileState {
 371             input: input,
 372             session: session,
 373             out_dir: out_dir.as_ref().map(|s| &**s),
 374             out_file: None,
 375             arena: None,
 376             arenas: None,
 377             krate: None,
 378             registry: None,
 379             cstore: None,
 380             crate_name: None,
 381             output_filenames: None,
 382             expanded_crate: None,
 383             hir_crate: None,
 384             hir_map: None,
 385             resolutions: None,
 386             analysis: None,
 387             tcx: None,
 388             trans: None,
 389         }
 390     }
 391
 392     fn state_after_parse(input: &'a Input,
 393                          session: &'tcx Session,
 394                          out_dir: &'a Option<PathBuf>,
 395                          out_file: &'a Option<PathBuf>,
 396                          krate: ast::Crate,
 397                          cstore: &'a CStore)
 398                          -> Self {
 399         CompileState {
 400             // Initialize the registry before moving `krate`
 401             registry: Some(Registry::new(&session, krate.span)),
 402             krate: Some(krate),
 403             cstore: Some(cstore),
 404             out_file: out_file.as_ref().map(|s| &**s),
 405             ..CompileState::empty(input, session, out_dir)
 406         }
 407     }
 408
 409     fn state_after_expand(input: &'a Input,
 410                           session: &'tcx Session,
 411                           out_dir: &'a Option<PathBuf>,
 412                           out_file: &'a Option<PathBuf>,
 413                           cstore: &'a CStore,
 414                           expanded_crate: &'a ast::Crate,
 415                           crate_name: &'a str)
 416                           -> Self {
 417         CompileState {
 418             crate_name: Some(crate_name),
 419             cstore: Some(cstore),
 420             expanded_crate: Some(expanded_crate),
 421             out_file: out_file.as_ref().map(|s| &**s),
 422             ..CompileState::empty(input, session, out_dir)
 423         }
 424     }
 425
 426     fn state_after_hir_lowering(input: &'a Input,
 427                                 session: &'tcx Session,
 428                                 out_dir: &'a Option<PathBuf>,
 429                                 out_file: &'a Option<PathBuf>,
 430                                 arena: &'tcx DroplessArena,
 431                                 arenas: &'tcx GlobalArenas<'tcx>,
 432                                 cstore: &'a CStore,
 433                                 hir_map: &'a hir_map::Map<'tcx>,
 434                                 analysis: &'a ty::CrateAnalysis,
 435                                 resolutions: &'a Resolutions,
 436                                 krate: &'a ast::Crate,
 437                                 hir_crate: &'a hir::Crate,
 438                                 crate_name: &'a str)
 439                                 -> Self {
 440         CompileState {
 441             crate_name: Some(crate_name),
 442             arena: Some(arena),
 443             arenas: Some(arenas),
 444             cstore: Some(cstore),
 445             hir_map: Some(hir_map),
 446             analysis: Some(analysis),
 447             resolutions: Some(resolutions),
 448             expanded_crate: Some(krate),
 449             hir_crate: Some(hir_crate),
 450             out_file: out_file.as_ref().map(|s| &**s),
 451             ..CompileState::empty(input, session, out_dir)
 452         }
 453     }
 454
 455     fn state_after_analysis(input: &'a Input,
 456                             session: &'tcx Session,
 457                             out_dir: &'a Option<PathBuf>,
 458                             out_file: &'a Option<PathBuf>,
 459                             krate: Option<&'a ast::Crate>,
 460                             hir_crate: &'a hir::Crate,
 461                             analysis: &'a ty::CrateAnalysis,
 462                             tcx: TyCtxt<'a, 'tcx, 'tcx>,
 463                             crate_name: &'a str)
 464                             -> Self {
 465         CompileState {
 466             analysis: Some(analysis),
 467             tcx: Some(tcx),
 468             expanded_crate: krate,
 469             hir_crate: Some(hir_crate),
 470             crate_name: Some(crate_name),
 471             out_file: out_file.as_ref().map(|s| &**s),
 472             ..CompileState::empty(input, session, out_dir)
 473         }
 474     }
 475
 476
 477     fn state_after_llvm(input: &'a Input,
 478                         session: &'tcx Session,
 479                         out_dir: &'a Option<PathBuf>,
 480                         out_file: &'a Option<PathBuf>,
 481                         trans: &'a trans::CrateTranslation)
 482                         -> Self {
 483         CompileState {
 484             trans: Some(trans),
 485             out_file: out_file.as_ref().map(|s| &**s),
 486             ..CompileState::empty(input, session, out_dir)
 487         }
 488     }
 489
 490     fn state_when_compilation_done(input: &'a Input,
 491                                     session: &'tcx Session,
 492                                     out_dir: &'a Option<PathBuf>,
 493                                     out_file: &'a Option<PathBuf>)
 494                                     -> Self {
 495         CompileState {
 496             out_file: out_file.as_ref().map(|s| &**s),
 497             ..CompileState::empty(input, session, out_dir)
 498         }
 499     }
 500 }
 501
 502 pub fn phase_1_parse_input<'a>(sess: &'a Session, input: &Input) -> PResult<'a, ast::Crate> {
 503     let continue_after_error = sess.opts.debugging_opts.continue_parse_after_error;
 504     sess.diagnostic().set_continue_after_error(continue_after_error);
 505
 506     let krate = time(sess.time_passes(), "parsing", || {
 507         match *input {
 508             Input::File(ref file) => {
 509                 parse::parse_crate_from_file(file, &sess.parse_sess)
 510             }
 511             Input::Str { ref input, ref name } => {
 512                 parse::parse_crate_from_source_str(name.clone(), input.clone(), &sess.parse_sess)
 513             }
 514         }
 515     })?;
 516
 517     sess.diagnostic().set_continue_after_error(true);
 518
 519     if sess.opts.debugging_opts.ast_json_noexpand {
 520         println!("{}", json::as_json(&krate));
 521     }
 522
 523     if sess.opts.debugging_opts.input_stats {
 524         println!("Lines of code:             {}", sess.codemap().count_lines());
 525         println!("Pre-expansion node count:  {}", count_nodes(&krate));
 526     }
 527
 528     if let Some(ref s) = sess.opts.debugging_opts.show_span {
 529         syntax::show_span::run(sess.diagnostic(), s, &krate);
 530     }
 531
 532     if sess.opts.debugging_opts.hir_stats {
 533         hir_stats::print_ast_stats(&krate, "PRE EXPANSION AST STATS");
 534     }
 535
 536     Ok(krate)
 537 }
 538
 539 fn count_nodes(krate: &ast::Crate) -> usize {
 540     let mut counter = NodeCounter::new();
 541     visit::walk_crate(&mut counter, krate);
 542     counter.count
 543 }
 544
 545 // For continuing compilation after a parsed crate has been
 546 // modified
 547
 548 pub struct ExpansionResult {
 549     pub expanded_crate: ast::Crate,
 550     pub defs: hir_map::Definitions,
 551     pub analysis: ty::CrateAnalysis,
 552     pub resolutions: Resolutions,
 553     pub hir_forest: hir_map::Forest,
 554 }
 555
 556 /// Run the "early phases" of the compiler: initial `cfg` processing,
 557 /// loading compiler plugins (including those from `addl_plugins`),
 558 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 559 /// harness if one is to be provided, injection of a dependency on the
 560 /// standard library and prelude, and name resolution.
 561 ///
 562 /// Returns `None` if we're aborting after handling -W help.
 563 pub fn phase_2_configure_and_expand<F>(sess: &Session,
 564                                        cstore: &CStore,
 565                                        krate: ast::Crate,
 566                                        registry: Option<Registry>,
 567                                        crate_name: &str,
 568                                        addl_plugins: Option<Vec<String>>,
 569                                        make_glob_map: MakeGlobMap,
 570                                        after_expand: F)
 571                                        -> Result<ExpansionResult, CompileIncomplete>
 572     where F: FnOnce(&ast::Crate) -> CompileResult,
 573 {
 574     let time_passes = sess.time_passes();
 575
 576     let (mut krate, features) = syntax::config::features(krate, &sess.parse_sess, sess.opts.test);
 577     // these need to be set "early" so that expansion sees `quote` if enabled.
 578     *sess.features.borrow_mut() = features;
 579
 580     *sess.crate_types.borrow_mut() = collect_crate_types(sess, &krate.attrs);
 581     *sess.crate_disambiguator.borrow_mut() = Symbol::intern(&compute_crate_disambiguator(sess));
 582
 583     time(time_passes, "recursion limit", || {
 584         middle::recursion_limit::update_limits(sess, &krate);
 585     });
 586
 587     krate = time(time_passes, "crate injection", || {
 588         let alt_std_name = sess.opts.alt_std_name.clone();
 589         syntax::std_inject::maybe_inject_crates_ref(krate, alt_std_name)
 590     });
 591
 592     let mut addl_plugins = Some(addl_plugins);
 593     let registrars = time(time_passes, "plugin loading", || {
 594         plugin::load::load_plugins(sess,
 595                                    &cstore,
 596                                    &krate,
 597                                    crate_name,
 598                                    addl_plugins.take().unwrap())
 599     });
 600
 601     let mut registry = registry.unwrap_or(Registry::new(sess, krate.span));
 602
 603     time(time_passes, "plugin registration", || {
 604         if sess.features.borrow().rustc_diagnostic_macros {
 605             registry.register_macro("__diagnostic_used",
 606                                     diagnostics::plugin::expand_diagnostic_used);
 607             registry.register_macro("__register_diagnostic",
 608                                     diagnostics::plugin::expand_register_diagnostic);
 609             registry.register_macro("__build_diagnostic_array",
 610                                     diagnostics::plugin::expand_build_diagnostic_array);
 611         }
 612
 613         for registrar in registrars {
 614             registry.args_hidden = Some(registrar.args);
 615             (registrar.fun)(&mut registry);
 616         }
 617     });
 618
 619     let whitelisted_legacy_custom_derives = registry.take_whitelisted_custom_derives();
 620     let Registry { syntax_exts, early_lint_passes, late_lint_passes, lint_groups,
 621                    llvm_passes, attributes, .. } = registry;
 622
 623     sess.track_errors(|| {
 624         let mut ls = sess.lint_store.borrow_mut();
 625         for pass in early_lint_passes {
 626             ls.register_early_pass(Some(sess), true, pass);
 627         }
 628         for pass in late_lint_passes {
 629             ls.register_late_pass(Some(sess), true, pass);
 630         }
 631
 632         for (name, to) in lint_groups {
 633             ls.register_group(Some(sess), true, name, to);
 634         }
 635
 636         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
 637         *sess.plugin_attributes.borrow_mut() = attributes.clone();
 638     })?;
 639
 640     // Lint plugins are registered; now we can process command line flags.
 641     if sess.opts.describe_lints {
 642         super::describe_lints(&sess.lint_store.borrow(), true);
 643         return Err(CompileIncomplete::Stopped);
 644     }
 645     sess.track_errors(|| sess.lint_store.borrow_mut().process_command_line(sess))?;
 646
 647     // Currently, we ignore the name resolution data structures for the purposes of dependency
 648     // tracking. Instead we will run name resolution and include its output in the hash of each
 649     // item, much like we do for macro expansion. In other words, the hash reflects not just
 650     // its contents but the results of name resolution on those contents. Hopefully we'll push
 651     // this back at some point.
 652     let _ignore = sess.dep_graph.in_ignore();
 653     let mut crate_loader = CrateLoader::new(sess, &cstore, crate_name);
 654     crate_loader.preprocess(&krate);
 655     let resolver_arenas = Resolver::arenas();
 656     let mut resolver = Resolver::new(sess,
 657                                      &krate,
 658                                      crate_name,
 659                                      make_glob_map,
 660                                      &mut crate_loader,
 661                                      &resolver_arenas);
 662     resolver.whitelisted_legacy_custom_derives = whitelisted_legacy_custom_derives;
 663     syntax_ext::register_builtins(&mut resolver, syntax_exts, sess.features.borrow().quote);
 664
 665     krate = time(time_passes, "expansion", || {
 666         // Windows dlls do not have rpaths, so they don't know how to find their
 667         // dependencies. It's up to us to tell the system where to find all the
 668         // dependent dlls. Note that this uses cfg!(windows) as opposed to
 669         // targ_cfg because syntax extensions are always loaded for the host
 670         // compiler, not for the target.
 671         //
 672         // This is somewhat of an inherently racy operation, however, as
 673         // multiple threads calling this function could possibly continue
 674         // extending PATH far beyond what it should. To solve this for now we
 675         // just don't add any new elements to PATH which are already there
 676         // within PATH. This is basically a targeted fix at #17360 for rustdoc
 677         // which runs rustc in parallel but has been seen (#33844) to cause
 678         // problems with PATH becoming too long.
 679         let mut old_path = OsString::new();
 680         if cfg!(windows) {
 681             old_path = env::var_os("PATH").unwrap_or(old_path);
 682             let mut new_path = sess.host_filesearch(PathKind::All)
 683                                    .get_dylib_search_paths();
 684             for path in env::split_paths(&old_path) {
 685                 if !new_path.contains(&path) {
 686                     new_path.push(path);
 687                 }
 688             }
 689             env::set_var("PATH",
 690                 &env::join_paths(new_path.iter()
 691                                          .filter(|p| env::join_paths(iter::once(p)).is_ok()))
 692                      .unwrap());
 693         }
 694         let features = sess.features.borrow();
 695         let cfg = syntax::ext::expand::ExpansionConfig {
 696             features: Some(&features),
 697             recursion_limit: sess.recursion_limit.get(),
 698             trace_mac: sess.opts.debugging_opts.trace_macros,
 699             should_test: sess.opts.test,
 700             ..syntax::ext::expand::ExpansionConfig::default(crate_name.to_string())
 701         };
 702
 703         let mut ecx = ExtCtxt::new(&sess.parse_sess, cfg, &mut resolver);
 704         let err_count = ecx.parse_sess.span_diagnostic.err_count();
 705
 706         let krate = ecx.monotonic_expander().expand_crate(krate);
 707
 708         ecx.check_unused_macros();
 709
 710         let mut missing_fragment_specifiers: Vec<_> =
 711             ecx.parse_sess.missing_fragment_specifiers.borrow().iter().cloned().collect();
 712         missing_fragment_specifiers.sort();
 713         for span in missing_fragment_specifiers {
 714             let lint = lint::builtin::MISSING_FRAGMENT_SPECIFIER;
 715             let msg = "missing fragment specifier".to_string();
 716             sess.add_lint(lint, ast::CRATE_NODE_ID, span, msg);
 717         }
 718         if ecx.parse_sess.span_diagnostic.err_count() - ecx.resolve_err_count > err_count {
 719             ecx.parse_sess.span_diagnostic.abort_if_errors();
 720         }
 721         if cfg!(windows) {
 722             env::set_var("PATH", &old_path);
 723         }
 724         krate
 725     });
 726
 727     krate = time(time_passes, "maybe building test harness", || {
 728         syntax::test::modify_for_testing(&sess.parse_sess,
 729                                          &mut resolver,
 730                                          sess.opts.test,
 731                                          krate,
 732                                          sess.diagnostic())
 733     });
 734
 735     // If we're in rustdoc we're always compiling as an rlib, but that'll trip a
 736     // bunch of checks in the `modify` function below. For now just skip this
 737     // step entirely if we're rustdoc as it's not too useful anyway.
 738     if !sess.opts.actually_rustdoc {
 739         krate = time(time_passes, "maybe creating a macro crate", || {
 740             let crate_types = sess.crate_types.borrow();
 741             let num_crate_types = crate_types.len();
 742             let is_proc_macro_crate = crate_types.contains(&config::CrateTypeProcMacro);
 743             let is_test_crate = sess.opts.test;
 744             syntax_ext::proc_macro_registrar::modify(&sess.parse_sess,
 745                                                      &mut resolver,
 746                                                      krate,
 747                                                      is_proc_macro_crate,
 748                                                      is_test_crate,
 749                                                      num_crate_types,
 750                                                      sess.diagnostic())
 751         });
 752     }
 753
 754     krate = time(time_passes, "creating allocators", || {
 755         allocator::expand::modify(&sess.parse_sess,
 756                                   &mut resolver,
 757                                   krate,
 758                                   sess.diagnostic())
 759     });
 760
 761     after_expand(&krate)?;
 762
 763     if sess.opts.debugging_opts.input_stats {
 764         println!("Post-expansion node count: {}", count_nodes(&krate));
 765     }
 766
 767     if sess.opts.debugging_opts.hir_stats {
 768         hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS");
 769     }
 770
 771     if sess.opts.debugging_opts.ast_json {
 772         println!("{}", json::as_json(&krate));
 773     }
 774
 775     time(time_passes,
 776          "checking for inline asm in case the target doesn't support it",
 777          || no_asm::check_crate(sess, &krate));
 778
 779     time(time_passes,
 780          "early lint checks",
 781          || lint::check_ast_crate(sess, &krate));
 782
 783     time(time_passes,
 784          "AST validation",
 785          || ast_validation::check_crate(sess, &krate));
 786
 787     time(time_passes, "name resolution", || -> CompileResult {
 788         resolver.resolve_crate(&krate);
 789         Ok(())
 790     })?;
 791
 792     if resolver.found_unresolved_macro {
 793         sess.parse_sess.span_diagnostic.abort_if_errors();
 794     }
 795
 796     // Needs to go *after* expansion to be able to check the results of macro expansion.
 797     time(time_passes, "complete gated feature checking", || {
 798         sess.track_errors(|| {
 799             syntax::feature_gate::check_crate(&krate,
 800                                               &sess.parse_sess,
 801                                               &sess.features.borrow(),
 802                                               &attributes,
 803                                               sess.opts.unstable_features);
 804         })
 805     })?;
 806
 807     // Lower ast -> hir.
 808     let hir_forest = time(time_passes, "lowering ast -> hir", || {
 809         let hir_crate = lower_crate(sess, &krate, &mut resolver);
 810
 811         if sess.opts.debugging_opts.hir_stats {
 812             hir_stats::print_hir_stats(&hir_crate);
 813         }
 814
 815         hir_map::Forest::new(hir_crate, &sess.dep_graph)
 816     });
 817
 818     // Discard hygiene data, which isn't required after lowering to HIR.
 819     if !keep_hygiene_data(sess) {
 820         syntax::ext::hygiene::clear_markings();
 821     }
 822
 823     Ok(ExpansionResult {
 824         expanded_crate: krate,
 825         defs: resolver.definitions,
 826         analysis: ty::CrateAnalysis {
 827             access_levels: Rc::new(AccessLevels::default()),
 828             reachable: Rc::new(NodeSet()),
 829             name: crate_name.to_string(),
 830             glob_map: if resolver.make_glob_map { Some(resolver.glob_map) } else { None },
 831         },
 832         resolutions: Resolutions {
 833             freevars: resolver.freevars,
 834             export_map: resolver.export_map,
 835             trait_map: resolver.trait_map,
 836             maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
 837         },
 838         hir_forest: hir_forest,
 839     })
 840 }
 841
 842 /// Run the resolution, typechecking, region checking and other
 843 /// miscellaneous analysis passes on the crate. Return various
 844 /// structures carrying the results of the analysis.
 845 pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 846                                                hir_map: hir_map::Map<'tcx>,
 847                                                mut analysis: ty::CrateAnalysis,
 848                                                resolutions: Resolutions,
 849                                                arena: &'tcx DroplessArena,
 850                                                arenas: &'tcx GlobalArenas<'tcx>,
 851                                                name: &str,
 852                                                f: F)
 853                                                -> Result<R, CompileIncomplete>
 854     where F: for<'a> FnOnce(TyCtxt<'a, 'tcx, 'tcx>,
 855                             ty::CrateAnalysis,
 856                             IncrementalHashesMap,
 857                             CompileResult) -> R
 858 {
 859     macro_rules! try_with_f {
 860         ($e: expr, ($t: expr, $a: expr, $h: expr)) => {
 861             match $e {
 862                 Ok(x) => x,
 863                 Err(x) => {
 864                     f($t, $a, $h, Err(x));
 865                     return Err(x);
 866                 }
 867             }
 868         }
 869     }
 870
 871     let time_passes = sess.time_passes();
 872
 873     let lang_items = time(time_passes, "language item collection", || {
 874         sess.track_errors(|| {
 875             middle::lang_items::collect_language_items(&sess, &hir_map)
 876         })
 877     })?;
 878
 879     let named_region_map = time(time_passes,
 880                                 "lifetime resolution",
 881                                 || middle::resolve_lifetime::krate(sess, &hir_map))?;
 882
 883     time(time_passes,
 884          "looking for entry point",
 885          || middle::entry::find_entry_point(sess, &hir_map));
 886
 887     sess.plugin_registrar_fn.set(time(time_passes, "looking for plugin registrar", || {
 888         plugin::build::find_plugin_registrar(sess.diagnostic(), &hir_map)
 889     }));
 890     sess.derive_registrar_fn.set(derive_registrar::find(&hir_map));
 891
 892     time(time_passes,
 893          "loop checking",
 894          || loops::check_crate(sess, &hir_map));
 895
 896     time(time_passes,
 897               "static item recursion checking",
 898               || static_recursion::check_crate(sess, &hir_map))?;
 899
 900     let index = stability::Index::new(&sess);
 901
 902     let mut local_providers = ty::maps::Providers::default();
 903     borrowck::provide(&mut local_providers);
 904     mir::provide(&mut local_providers);
 905     reachable::provide(&mut local_providers);
 906     rustc_privacy::provide(&mut local_providers);
 907     trans::provide(&mut local_providers);
 908     typeck::provide(&mut local_providers);
 909     ty::provide(&mut local_providers);
 910     traits::provide(&mut local_providers);
 911     reachable::provide(&mut local_providers);
 912     rustc_const_eval::provide(&mut local_providers);
 913     middle::region::provide(&mut local_providers);
 914     cstore::provide_local(&mut local_providers);
 915
 916     let mut extern_providers = ty::maps::Providers::default();
 917     cstore::provide(&mut extern_providers);
 918     trans::provide(&mut extern_providers);
 919     ty::provide_extern(&mut extern_providers);
 920     traits::provide_extern(&mut extern_providers);
 921     // FIXME(eddyb) get rid of this once we replace const_eval with miri.
 922     rustc_const_eval::provide(&mut extern_providers);
 923
 924     // Setup the MIR passes that we want to run.
 925     let mut passes = Passes::new();
 926     passes.push_hook(mir::transform::dump_mir::DumpMir);
 927
 928     // Remove all `EndRegion` statements that are not involved in borrows.
 929     passes.push_pass(MIR_CONST, mir::transform::clean_end_regions::CleanEndRegions);
 930
 931     // What we need to do constant evaluation.
 932     passes.push_pass(MIR_CONST, mir::transform::simplify::SimplifyCfg::new("initial"));
 933     passes.push_pass(MIR_CONST, mir::transform::type_check::TypeckMir);
 934     passes.push_pass(MIR_CONST, mir::transform::rustc_peek::SanityCheck);
 935
 936     // What we need to run borrowck etc.
 937     passes.push_pass(MIR_VALIDATED, mir::transform::qualify_consts::QualifyAndPromoteConstants);
 938     passes.push_pass(MIR_VALIDATED,
 939                      mir::transform::simplify_branches::SimplifyBranches::new("initial"));
 940     passes.push_pass(MIR_VALIDATED, mir::transform::simplify::SimplifyCfg::new("qualify-consts"));
 941     passes.push_pass(MIR_VALIDATED, mir::transform::nll::NLL);
 942
 943     // Optimizations begin.
 944     passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads);
 945     passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyCfg::new("no-landing-pads"));
 946
 947     // From here on out, regions are gone.
 948     passes.push_pass(MIR_OPTIMIZED, mir::transform::erase_regions::EraseRegions);
 949     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::AddCallGuards);
 950     passes.push_pass(MIR_OPTIMIZED, mir::transform::elaborate_drops::ElaborateDrops);
 951     passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads);
 952     passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyCfg::new("elaborate-drops"));
 953
 954     // No lifetime analysis based on borrowing can be done from here on out.
 955     passes.push_pass(MIR_OPTIMIZED, mir::transform::inline::Inline);
 956     passes.push_pass(MIR_OPTIMIZED, mir::transform::instcombine::InstCombine);
 957     passes.push_pass(MIR_OPTIMIZED, mir::transform::deaggregator::Deaggregator);
 958     passes.push_pass(MIR_OPTIMIZED, mir::transform::copy_prop::CopyPropagation);
 959     passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyLocals);
 960     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::AddCallGuards);
 961     passes.push_pass(MIR_OPTIMIZED, mir::transform::dump_mir::Marker("PreTrans"));
 962
 963     TyCtxt::create_and_enter(sess,
 964                              local_providers,
 965                              extern_providers,
 966                              Rc::new(passes),
 967                              arenas,
 968                              arena,
 969                              resolutions,
 970                              named_region_map,
 971                              hir_map,
 972                              lang_items,
 973                              index,
 974                              name,
 975                              |tcx| {
 976         let incremental_hashes_map =
 977             time(time_passes,
 978                  "compute_incremental_hashes_map",
 979                  || rustc_incremental::compute_incremental_hashes_map(tcx));
 980
 981         time(time_passes,
 982              "load_dep_graph",
 983              || rustc_incremental::load_dep_graph(tcx, &incremental_hashes_map));
 984
 985         time(time_passes, "stability index", || {
 986             tcx.stability.borrow_mut().build(tcx)
 987         });
 988
 989         time(time_passes,
 990              "stability checking",
 991              || stability::check_unstable_api_usage(tcx));
 992
 993         // passes are timed inside typeck
 994         try_with_f!(typeck::check_crate(tcx), (tcx, analysis, incremental_hashes_map));
 995
 996         time(time_passes,
 997              "const checking",
 998              || consts::check_crate(tcx));
 999
1000         analysis.access_levels =
1001             time(time_passes, "privacy checking", || rustc_privacy::check_crate(tcx));
1002
1003         time(time_passes,
1004              "intrinsic checking",
1005              || middle::intrinsicck::check_crate(tcx));
1006
1007         time(time_passes,
1008              "effect checking",
1009              || middle::effect::check_crate(tcx));
1010
1011         time(time_passes,
1012              "match checking",
1013              || check_match::check_crate(tcx));
1014
1015         // this must run before MIR dump, because
1016         // "not all control paths return a value" is reported here.
1017         //
1018         // maybe move the check to a MIR pass?
1019         time(time_passes,
1020              "liveness checking",
1021              || middle::liveness::check_crate(tcx));
1022
1023         time(time_passes,
1024              "borrow checking",
1025              || borrowck::check_crate(tcx));
1026
1027         // Avoid overwhelming user with errors if type checking failed.
1028         // I'm not sure how helpful this is, to be honest, but it avoids
1029         // a
1030         // lot of annoying errors in the compile-fail tests (basically,
1031         // lint warnings and so on -- kindck used to do this abort, but
1032         // kindck is gone now). -nmatsakis
1033         if sess.err_count() > 0 {
1034             return Ok(f(tcx, analysis, incremental_hashes_map, sess.compile_status()));
1035         }
1036
1037         analysis.reachable =
1038             time(time_passes,
1039                  "reachability checking",
1040                  || reachable::find_reachable(tcx));
1041
1042         time(time_passes, "death checking", || middle::dead::check_crate(tcx));
1043
1044         time(time_passes, "unused lib feature checking", || {
1045             stability::check_unused_or_stable_features(tcx)
1046         });
1047
1048         time(time_passes, "lint checking", || lint::check_crate(tcx));
1049
1050         return Ok(f(tcx, analysis, incremental_hashes_map, tcx.sess.compile_status()));
1051     })
1052 }
1053
1054 /// Run the translation phase to LLVM, after which the AST and analysis can
1055 /// be discarded.
1056 pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1057                                            analysis: ty::CrateAnalysis,
1058                                            incremental_hashes_map: &IncrementalHashesMap,
1059                                            output_filenames: &OutputFilenames)
1060                                            -> trans::CrateTranslation {
1061     let time_passes = tcx.sess.time_passes();
1062
1063     time(time_passes,
1064          "resolving dependency formats",
1065          || dependency_format::calculate(tcx));
1066
1067     let translation =
1068         time(time_passes,
1069              "translation",
1070              move || trans::trans_crate(tcx, analysis, &incremental_hashes_map, output_filenames));
1071
1072     time(time_passes,
1073          "assert dep graph",
1074          || rustc_incremental::assert_dep_graph(tcx));
1075
1076     time(time_passes,
1077          "serialize dep graph",
1078          || rustc_incremental::save_dep_graph(tcx,
1079                                               &incremental_hashes_map,
1080                                               &translation.metadata.hashes,
1081                                               translation.link.crate_hash));
1082     translation
1083 }
1084
1085 /// Run LLVM itself, producing a bitcode file, assembly file or object file
1086 /// as a side effect.
1087 pub fn phase_5_run_llvm_passes(sess: &Session,
1088                                trans: &trans::CrateTranslation,
1089                                outputs: &OutputFilenames) -> CompileResult {
1090     if sess.opts.cg.no_integrated_as ||
1091         (sess.target.target.options.no_integrated_as &&
1092          (outputs.outputs.contains_key(&OutputType::Object) ||
1093           outputs.outputs.contains_key(&OutputType::Exe)))
1094     {
1095         let output_types = OutputTypes::new(&[(OutputType::Assembly, None)]);
1096         time(sess.time_passes(),
1097              "LLVM passes",
1098              || write::run_passes(sess, trans, &output_types, outputs));
1099
1100         write::run_assembler(sess, outputs);
1101
1102         // HACK the linker expects the object file to be named foo.0.o but
1103         // `run_assembler` produces an object named just foo.o. Rename it if we
1104         // are going to build an executable
1105         if sess.opts.output_types.contains_key(&OutputType::Exe) {
1106             let f = outputs.path(OutputType::Object);
1107             rename_or_copy_remove(&f,
1108                      f.with_file_name(format!("{}.0.o",
1109                                               f.file_stem().unwrap().to_string_lossy()))).unwrap();
1110         }
1111
1112         // Remove assembly source, unless --save-temps was specified
1113         if !sess.opts.cg.save_temps {
1114             fs::remove_file(&outputs.temp_path(OutputType::Assembly, None)).unwrap();
1115         }
1116     } else {
1117         time(sess.time_passes(),
1118              "LLVM passes",
1119              || write::run_passes(sess, trans, &sess.opts.output_types, outputs));
1120     }
1121
1122     time(sess.time_passes(),
1123          "serialize work products",
1124          move || rustc_incremental::save_work_products(sess));
1125
1126     sess.compile_status()
1127 }
1128
1129 /// Run the linker on any artifacts that resulted from the LLVM run.
1130 /// This should produce either a finished executable or library.
1131 pub fn phase_6_link_output(sess: &Session,
1132                            trans: &trans::CrateTranslation,
1133                            outputs: &OutputFilenames) {
1134     time(sess.time_passes(),
1135          "linking",
1136          || link::link_binary(sess, trans, outputs, &trans.crate_name.as_str()));
1137 }
1138
1139 fn escape_dep_filename(filename: &str) -> String {
1140     // Apparently clang and gcc *only* escape spaces:
1141     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
1142     filename.replace(" ", "\\ ")
1143 }
1144
1145 fn write_out_deps(sess: &Session, outputs: &OutputFilenames, crate_name: &str) {
1146     let mut out_filenames = Vec::new();
1147     for output_type in sess.opts.output_types.keys() {
1148         let file = outputs.path(*output_type);
1149         match *output_type {
1150             OutputType::Exe => {
1151                 for output in sess.crate_types.borrow().iter() {
1152                     let p = link::filename_for_input(sess, *output, crate_name, outputs);
1153                     out_filenames.push(p);
1154                 }
1155             }
1156             _ => {
1157                 out_filenames.push(file);
1158             }
1159         }
1160     }
1161
1162     // Write out dependency rules to the dep-info file if requested
1163     if !sess.opts.output_types.contains_key(&OutputType::DepInfo) {
1164         return;
1165     }
1166     let deps_filename = outputs.path(OutputType::DepInfo);
1167
1168     let result =
1169         (|| -> io::Result<()> {
1170             // Build a list of files used to compile the output and
1171             // write Makefile-compatible dependency rules
1172             let files: Vec<String> = sess.codemap()
1173                                          .files()
1174                                          .iter()
1175                                          .filter(|fmap| fmap.is_real_file())
1176                                          .filter(|fmap| !fmap.is_imported())
1177                                          .map(|fmap| escape_dep_filename(&fmap.name))
1178                                          .collect();
1179             let mut file = fs::File::create(&deps_filename)?;
1180             for path in &out_filenames {
1181                 write!(file, "{}: {}\n\n", path.display(), files.join(" "))?;
1182             }
1183
1184             // Emit a fake target for each input file to the compilation. This
1185             // prevents `make` from spitting out an error if a file is later
1186             // deleted. For more info see #28735
1187             for path in files {
1188                 writeln!(file, "{}:", path)?;
1189             }
1190             Ok(())
1191         })();
1192
1193     match result {
1194         Ok(()) => {}
1195         Err(e) => {
1196             sess.fatal(&format!("error writing dependencies to `{}`: {}",
1197                                 deps_filename.display(),
1198                                 e));
1199         }
1200     }
1201 }
1202
1203 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
1204     // Unconditionally collect crate types from attributes to make them used
1205     let attr_types: Vec<config::CrateType> =
1206         attrs.iter()
1207              .filter_map(|a| {
1208                  if a.check_name("crate_type") {
1209                      match a.value_str() {
1210                          Some(ref n) if *n == "rlib" => {
1211                              Some(config::CrateTypeRlib)
1212                          }
1213                          Some(ref n) if *n == "dylib" => {
1214                              Some(config::CrateTypeDylib)
1215                          }
1216                          Some(ref n) if *n == "cdylib" => {
1217                              Some(config::CrateTypeCdylib)
1218                          }
1219                          Some(ref n) if *n == "lib" => {
1220                              Some(config::default_lib_output())
1221                          }
1222                          Some(ref n) if *n == "staticlib" => {
1223                              Some(config::CrateTypeStaticlib)
1224                          }
1225                          Some(ref n) if *n == "proc-macro" => {
1226                              Some(config::CrateTypeProcMacro)
1227                          }
1228                          Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
1229                          Some(_) => {
1230                              session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
1231                                               ast::CRATE_NODE_ID,
1232                                               a.span,
1233                                               "invalid `crate_type` value".to_string());
1234                              None
1235                          }
1236                          _ => {
1237                              session.struct_span_err(a.span, "`crate_type` requires a value")
1238                                  .note("for example: `#![crate_type=\"lib\"]`")
1239                                  .emit();
1240                              None
1241                          }
1242                      }
1243                  } else {
1244                      None
1245                  }
1246              })
1247              .collect();
1248
1249     // If we're generating a test executable, then ignore all other output
1250     // styles at all other locations
1251     if session.opts.test {
1252         return vec![config::CrateTypeExecutable];
1253     }
1254
1255     // Only check command line flags if present. If no types are specified by
1256     // command line, then reuse the empty `base` Vec to hold the types that
1257     // will be found in crate attributes.
1258     let mut base = session.opts.crate_types.clone();
1259     if base.is_empty() {
1260         base.extend(attr_types);
1261         if base.is_empty() {
1262             base.push(link::default_output_for_target(session));
1263         }
1264         base.sort();
1265         base.dedup();
1266     }
1267
1268     base.into_iter()
1269         .filter(|crate_type| {
1270             let res = !link::invalid_output_for_target(session, *crate_type);
1271
1272             if !res {
1273                 session.warn(&format!("dropping unsupported crate type `{}` for target `{}`",
1274                                       *crate_type,
1275                                       session.opts.target_triple));
1276             }
1277
1278             res
1279         })
1280         .collect()
1281 }
1282
1283 pub fn compute_crate_disambiguator(session: &Session) -> String {
1284     use std::hash::Hasher;
1285
1286     // The crate_disambiguator is a 128 bit hash. The disambiguator is fed
1287     // into various other hashes quite a bit (symbol hashes, incr. comp. hashes,
1288     // debuginfo type IDs, etc), so we don't want it to be too wide. 128 bits
1289     // should still be safe enough to avoid collisions in practice.
1290     // FIXME(mw): It seems that the crate_disambiguator is used everywhere as
1291     //            a hex-string instead of raw bytes. We should really use the
1292     //            smaller representation.
1293     let mut hasher = StableHasher::<Fingerprint>::new();
1294
1295     let mut metadata = session.opts.cg.metadata.clone();
1296     // We don't want the crate_disambiguator to dependent on the order
1297     // -C metadata arguments, so sort them:
1298     metadata.sort();
1299     // Every distinct -C metadata value is only incorporated once:
1300     metadata.dedup();
1301
1302     hasher.write(b"metadata");
1303     for s in &metadata {
1304         // Also incorporate the length of a metadata string, so that we generate
1305         // different values for `-Cmetadata=ab -Cmetadata=c` and
1306         // `-Cmetadata=a -Cmetadata=bc`
1307         hasher.write_usize(s.len());
1308         hasher.write(s.as_bytes());
1309     }
1310
1311     // If this is an executable, add a special suffix, so that we don't get
1312     // symbol conflicts when linking against a library of the same name.
1313     let is_exe = session.crate_types.borrow().contains(&config::CrateTypeExecutable);
1314
1315     format!("{}{}", hasher.finish().to_hex(), if is_exe { "-exe" } else {""})
1316 }
1317
1318 pub fn build_output_filenames(input: &Input,
1319                               odir: &Option<PathBuf>,
1320                               ofile: &Option<PathBuf>,
1321                               attrs: &[ast::Attribute],
1322                               sess: &Session)
1323                               -> OutputFilenames {
1324     match *ofile {
1325         None => {
1326             // "-" as input file will cause the parser to read from stdin so we
1327             // have to make up a name
1328             // We want to toss everything after the final '.'
1329             let dirpath = match *odir {
1330                 Some(ref d) => d.clone(),
1331                 None => PathBuf::new(),
1332             };
1333
1334             // If a crate name is present, we use it as the link name
1335             let stem = sess.opts
1336                            .crate_name
1337                            .clone()
1338                            .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
1339                            .unwrap_or(input.filestem());
1340
1341             OutputFilenames {
1342                 out_directory: dirpath,
1343                 out_filestem: stem,
1344                 single_output_file: None,
1345                 extra: sess.opts.cg.extra_filename.clone(),
1346                 outputs: sess.opts.output_types.clone(),
1347             }
1348         }
1349
1350         Some(ref out_file) => {
1351             let unnamed_output_types = sess.opts
1352                                            .output_types
1353                                            .values()
1354                                            .filter(|a| a.is_none())
1355                                            .count();
1356             let ofile = if unnamed_output_types > 1 {
1357                 sess.warn("due to multiple output types requested, the explicitly specified \
1358                            output file name will be adapted for each output type");
1359                 None
1360             } else {
1361                 Some(out_file.clone())
1362             };
1363             if *odir != None {
1364                 sess.warn("ignoring --out-dir flag due to -o flag.");
1365             }
1366
1367             let cur_dir = Path::new("");
1368
1369             OutputFilenames {
1370                 out_directory: out_file.parent().unwrap_or(cur_dir).to_path_buf(),
1371                 out_filestem: out_file.file_stem()
1372                                       .unwrap_or(OsStr::new(""))
1373                                       .to_str()
1374                                       .unwrap()
1375                                       .to_string(),
1376                 single_output_file: ofile,
1377                 extra: sess.opts.cg.extra_filename.clone(),
1378                 outputs: sess.opts.output_types.clone(),
1379             }
1380         }
1381     }
1382 }