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