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, stability, reachable};
  22 #[cfg(feature="llvm")]
  23 use rustc::middle::dependency_format;
  24 use rustc::middle::privacy::AccessLevels;
  25 use rustc::mir::transform::{MIR_CONST, MIR_VALIDATED, MIR_OPTIMIZED, Passes};
  26 use rustc::ty::{self, TyCtxt, Resolutions, GlobalArenas};
  27 use rustc::traits;
  28 use rustc::util::common::{ErrorReported, time};
  29 use rustc::util::nodemap::NodeSet;
  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 #[cfg(feature="llvm")]
  37 use rustc_trans::back::{link, write};
  38 #[cfg(feature="llvm")]
  39 use rustc_trans as trans;
  40 use rustc_typeck as typeck;
  41 use rustc_privacy;
  42 use rustc_plugin::registry::Registry;
  43 use rustc_plugin as plugin;
  44 use rustc_passes::{ast_validation, no_asm, loops, consts, static_recursion, hir_stats};
  45 use rustc_const_eval::{self, check_match};
  46 use super::Compilation;
  47
  48 use serialize::json;
  49
  50 use std::env;
  51 use std::ffi::{OsString, OsStr};
  52 use std::fs;
  53 use std::io::{self, Write};
  54 use std::iter;
  55 use std::path::{Path, PathBuf};
  56 use std::rc::Rc;
  57 use syntax::{ast, diagnostics, visit};
  58 use syntax::attr;
  59 use syntax::ext::base::ExtCtxt;
  60 use syntax::parse::{self, PResult};
  61 use syntax::symbol::Symbol;
  62 use syntax::util::node_count::NodeCounter;
  63 use syntax;
  64 use syntax_ext;
  65 use arena::DroplessArena;
  66
  67 use derive_registrar;
  68
  69 pub fn compile_input(sess: &Session,
  70                      cstore: &CStore,
  71                      input: &Input,
  72                      outdir: &Option<PathBuf>,
  73                      output: &Option<PathBuf>,
  74                      addl_plugins: Option<Vec<String>>,
  75                      control: &CompileController) -> CompileResult {
  76     use rustc_trans::back::write::OngoingCrateTranslation;
  77
  78     macro_rules! controller_entry_point {
  79         ($point: ident, $tsess: expr, $make_state: expr, $phase_result: expr) => {{
  80             let state = &mut $make_state;
  81             let phase_result: &CompileResult = &$phase_result;
  82             if phase_result.is_ok() || control.$point.run_callback_on_error {
  83                 (control.$point.callback)(state);
  84             }
  85
  86             if control.$point.stop == Compilation::Stop {
  87                 // FIXME: shouldn't this return Err(CompileIncomplete::Stopped)
  88                 // if there are no errors?
  89                 return $tsess.compile_status();
  90             }
  91         }}
  92     }
  93
  94     // We need nested scopes here, because the intermediate results can keep
  95     // large chunks of memory alive and we want to free them as soon as
  96     // possible to keep the peak memory usage low
  97     let (outputs, trans): (OutputFilenames, OngoingCrateTranslation) = {
  98         let krate = match phase_1_parse_input(control, sess, input) {
  99             Ok(krate) => krate,
 100             Err(mut parse_error) => {
 101                 parse_error.emit();
 102                 return Err(CompileIncomplete::Errored(ErrorReported));
 103             }
 104         };
 105
 106         let (krate, registry) = {
 107             let mut compile_state = CompileState::state_after_parse(input,
 108                                                                     sess,
 109                                                                     outdir,
 110                                                                     output,
 111                                                                     krate,
 112                                                                     &cstore);
 113             controller_entry_point!(after_parse,
 114                                     sess,
 115                                     compile_state,
 116                                     Ok(()));
 117
 118             (compile_state.krate.unwrap(), compile_state.registry)
 119         };
 120
 121         let outputs = build_output_filenames(input, outdir, output, &krate.attrs, sess);
 122         let crate_name =
 123             ::rustc_trans_utils::link::find_crate_name(Some(sess), &krate.attrs, input);
 124         let ExpansionResult { expanded_crate, defs, analysis, resolutions, mut hir_forest } = {
 125             phase_2_configure_and_expand(
 126                 sess, &cstore, krate, registry, &crate_name, addl_plugins, control.make_glob_map,
 127                 |expanded_crate| {
 128                     let mut state = CompileState::state_after_expand(
 129                         input, sess, outdir, output, &cstore, expanded_crate, &crate_name,
 130                     );
 131                     controller_entry_point!(after_expand, sess, state, Ok(()));
 132                     Ok(())
 133                 }
 134             )?
 135         };
 136
 137         write_out_deps(sess, &outputs, &crate_name);
 138         if sess.opts.output_types.contains_key(&OutputType::DepInfo) &&
 139             sess.opts.output_types.keys().count() == 1 {
 140             return Ok(())
 141         }
 142
 143         let arena = DroplessArena::new();
 144         let arenas = GlobalArenas::new();
 145
 146         // Construct the HIR map
 147         let hir_map = time(sess.time_passes(),
 148                            "indexing hir",
 149                            || hir_map::map_crate(&mut hir_forest, defs));
 150
 151         {
 152             let _ignore = hir_map.dep_graph.in_ignore();
 153             controller_entry_point!(after_hir_lowering,
 154                                     sess,
 155                                     CompileState::state_after_hir_lowering(input,
 156                                                                   sess,
 157                                                                   outdir,
 158                                                                   output,
 159                                                                   &arena,
 160                                                                   &arenas,
 161                                                                   &cstore,
 162                                                                   &hir_map,
 163                                                                   &analysis,
 164                                                                   &resolutions,
 165                                                                   &expanded_crate,
 166                                                                   &hir_map.krate(),
 167                                                                   &crate_name),
 168                                     Ok(()));
 169         }
 170
 171         time(sess.time_passes(), "attribute checking", || {
 172             hir::check_attr::check_crate(sess, &expanded_crate);
 173         });
 174
 175         let opt_crate = if control.keep_ast {
 176             Some(&expanded_crate)
 177         } else {
 178             drop(expanded_crate);
 179             None
 180         };
 181
 182         phase_3_run_analysis_passes(sess,
 183                                     hir_map,
 184                                     analysis,
 185                                     resolutions,
 186                                     &arena,
 187                                     &arenas,
 188                                     &crate_name,
 189                                     |tcx, analysis, incremental_hashes_map, result| {
 190             {
 191                 // Eventually, we will want to track plugins.
 192                 let _ignore = tcx.dep_graph.in_ignore();
 193
 194                 let mut state = CompileState::state_after_analysis(input,
 195                                                                    sess,
 196                                                                    outdir,
 197                                                                    output,
 198                                                                    opt_crate,
 199                                                                    tcx.hir.krate(),
 200                                                                    &analysis,
 201                                                                    tcx,
 202                                                                    &crate_name);
 203                 (control.after_analysis.callback)(&mut state);
 204
 205                 if control.after_analysis.stop == Compilation::Stop {
 206                     return result.and_then(|_| Err(CompileIncomplete::Stopped));
 207                 }
 208             }
 209
 210             result?;
 211
 212             if log_enabled!(::log::LogLevel::Info) {
 213                 println!("Pre-trans");
 214                 tcx.print_debug_stats();
 215             }
 216
 217             #[cfg(feature="llvm")]
 218             let trans = phase_4_translate_to_llvm(tcx, analysis, incremental_hashes_map,
 219                                                   &outputs);
 220
 221             if log_enabled!(::log::LogLevel::Info) {
 222                 println!("Post-trans");
 223                 tcx.print_debug_stats();
 224             }
 225
 226             if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
 227                 if let Err(e) = mir::transform::dump_mir::emit_mir(tcx, &outputs) {
 228                     sess.err(&format!("could not emit MIR: {}", e));
 229                     sess.abort_if_errors();
 230                 }
 231             }
 232
 233             #[cfg(not(feature="llvm"))]
 234             {
 235                 let _ = incremental_hashes_map;
 236                 sess.err(&format!("LLVM is not supported by this rustc"));
 237                 sess.abort_if_errors();
 238                 unreachable!();
 239             }
 240
 241             #[cfg(feature="llvm")]
 242             Ok((outputs, trans))
 243         })??
 244     };
 245
 246     #[cfg(not(feature="llvm"))]
 247     {
 248         let _ = outputs;
 249         let _ = trans;
 250         unreachable!();
 251     }
 252
 253     #[cfg(feature="llvm")]
 254     {
 255         if sess.opts.debugging_opts.print_type_sizes {
 256             sess.code_stats.borrow().print_type_sizes();
 257         }
 258
 259         let (phase5_result, trans) = phase_5_run_llvm_passes(sess, trans);
 260
 261         controller_entry_point!(after_llvm,
 262                                 sess,
 263                                 CompileState::state_after_llvm(input, sess, outdir, output, &trans),
 264                                 phase5_result);
 265         phase5_result?;
 266
 267         phase_6_link_output(sess, &trans, &outputs);
 268
 269         // Now that we won't touch anything in the incremental compilation directory
 270         // any more, we can finalize it (which involves renaming it)
 271         rustc_incremental::finalize_session_directory(sess, trans.link.crate_hash);
 272
 273         if sess.opts.debugging_opts.perf_stats {
 274             sess.print_perf_stats();
 275         }
 276
 277         controller_entry_point!(
 278             compilation_done,
 279             sess,
 280             CompileState::state_when_compilation_done(input, sess, outdir, output),
 281             Ok(())
 282         );
 283
 284         Ok(())
 285     }
 286 }
 287
 288 fn keep_hygiene_data(sess: &Session) -> bool {
 289     sess.opts.debugging_opts.keep_hygiene_data
 290 }
 291
 292
 293 /// The name used for source code that doesn't originate in a file
 294 /// (e.g. source from stdin or a string)
 295 pub fn anon_src() -> String {
 296     "<anon>".to_string()
 297 }
 298
 299 pub fn source_name(input: &Input) -> String {
 300     match *input {
 301         // FIXME (#9639): This needs to handle non-utf8 paths
 302         Input::File(ref ifile) => ifile.to_str().unwrap().to_string(),
 303         Input::Str { ref name, .. } => name.clone(),
 304     }
 305 }
 306
 307 /// CompileController is used to customise compilation, it allows compilation to
 308 /// be stopped and/or to call arbitrary code at various points in compilation.
 309 /// It also allows for various flags to be set to influence what information gets
 310 /// collected during compilation.
 311 ///
 312 /// This is a somewhat higher level controller than a Session - the Session
 313 /// controls what happens in each phase, whereas the CompileController controls
 314 /// whether a phase is run at all and whether other code (from outside the
 315 /// compiler) is run between phases.
 316 ///
 317 /// Note that if compilation is set to stop and a callback is provided for a
 318 /// given entry point, the callback is called before compilation is stopped.
 319 ///
 320 /// Expect more entry points to be added in the future.
 321 pub struct CompileController<'a> {
 322     pub after_parse: PhaseController<'a>,
 323     pub after_expand: PhaseController<'a>,
 324     pub after_hir_lowering: PhaseController<'a>,
 325     pub after_analysis: PhaseController<'a>,
 326     pub after_llvm: PhaseController<'a>,
 327     pub compilation_done: PhaseController<'a>,
 328
 329     // FIXME we probably want to group the below options together and offer a
 330     // better API, rather than this ad-hoc approach.
 331     pub make_glob_map: MakeGlobMap,
 332     // Whether the compiler should keep the ast beyond parsing.
 333     pub keep_ast: bool,
 334     // -Zcontinue-parse-after-error
 335     pub continue_parse_after_error: bool,
 336 }
 337
 338 impl<'a> CompileController<'a> {
 339     pub fn basic() -> CompileController<'a> {
 340         CompileController {
 341             after_parse: PhaseController::basic(),
 342             after_expand: PhaseController::basic(),
 343             after_hir_lowering: PhaseController::basic(),
 344             after_analysis: PhaseController::basic(),
 345             after_llvm: PhaseController::basic(),
 346             compilation_done: PhaseController::basic(),
 347             make_glob_map: MakeGlobMap::No,
 348             keep_ast: false,
 349             continue_parse_after_error: false,
 350         }
 351     }
 352 }
 353
 354 pub struct PhaseController<'a> {
 355     pub stop: Compilation,
 356     // If true then the compiler will try to run the callback even if the phase
 357     // ends with an error. Note that this is not always possible.
 358     pub run_callback_on_error: bool,
 359     pub callback: Box<Fn(&mut CompileState) + 'a>,
 360 }
 361
 362 impl<'a> PhaseController<'a> {
 363     pub fn basic() -> PhaseController<'a> {
 364         PhaseController {
 365             stop: Compilation::Continue,
 366             run_callback_on_error: false,
 367             callback: box |_| {},
 368         }
 369     }
 370 }
 371
 372 /// State that is passed to a callback. What state is available depends on when
 373 /// during compilation the callback is made. See the various constructor methods
 374 /// (`state_*`) in the impl to see which data is provided for any given entry point.
 375 pub struct CompileState<'a, 'tcx: 'a> {
 376     pub input: &'a Input,
 377     pub session: &'tcx Session,
 378     pub krate: Option<ast::Crate>,
 379     pub registry: Option<Registry<'a>>,
 380     pub cstore: Option<&'a CStore>,
 381     pub crate_name: Option<&'a str>,
 382     pub output_filenames: Option<&'a OutputFilenames>,
 383     pub out_dir: Option<&'a Path>,
 384     pub out_file: Option<&'a Path>,
 385     pub arena: Option<&'tcx DroplessArena>,
 386     pub arenas: Option<&'tcx GlobalArenas<'tcx>>,
 387     pub expanded_crate: Option<&'a ast::Crate>,
 388     pub hir_crate: Option<&'a hir::Crate>,
 389     pub hir_map: Option<&'a hir_map::Map<'tcx>>,
 390     pub resolutions: Option<&'a Resolutions>,
 391     pub analysis: Option<&'a ty::CrateAnalysis>,
 392     pub tcx: Option<TyCtxt<'a, 'tcx, 'tcx>>,
 393     pub trans: Option<&'a trans::CrateTranslation>,
 394 }
 395
 396 impl<'a, 'tcx> CompileState<'a, 'tcx> {
 397     fn empty(input: &'a Input,
 398              session: &'tcx Session,
 399              out_dir: &'a Option<PathBuf>)
 400              -> Self {
 401         CompileState {
 402             input: input,
 403             session: session,
 404             out_dir: out_dir.as_ref().map(|s| &**s),
 405             out_file: None,
 406             arena: None,
 407             arenas: None,
 408             krate: None,
 409             registry: None,
 410             cstore: None,
 411             crate_name: None,
 412             output_filenames: None,
 413             expanded_crate: None,
 414             hir_crate: None,
 415             hir_map: None,
 416             resolutions: None,
 417             analysis: None,
 418             tcx: None,
 419             trans: None,
 420         }
 421     }
 422
 423     fn state_after_parse(input: &'a Input,
 424                          session: &'tcx Session,
 425                          out_dir: &'a Option<PathBuf>,
 426                          out_file: &'a Option<PathBuf>,
 427                          krate: ast::Crate,
 428                          cstore: &'a CStore)
 429                          -> Self {
 430         CompileState {
 431             // Initialize the registry before moving `krate`
 432             registry: Some(Registry::new(&session, krate.span)),
 433             krate: Some(krate),
 434             cstore: Some(cstore),
 435             out_file: out_file.as_ref().map(|s| &**s),
 436             ..CompileState::empty(input, session, out_dir)
 437         }
 438     }
 439
 440     fn state_after_expand(input: &'a Input,
 441                           session: &'tcx Session,
 442                           out_dir: &'a Option<PathBuf>,
 443                           out_file: &'a Option<PathBuf>,
 444                           cstore: &'a CStore,
 445                           expanded_crate: &'a ast::Crate,
 446                           crate_name: &'a str)
 447                           -> Self {
 448         CompileState {
 449             crate_name: Some(crate_name),
 450             cstore: Some(cstore),
 451             expanded_crate: Some(expanded_crate),
 452             out_file: out_file.as_ref().map(|s| &**s),
 453             ..CompileState::empty(input, session, out_dir)
 454         }
 455     }
 456
 457     fn state_after_hir_lowering(input: &'a Input,
 458                                 session: &'tcx Session,
 459                                 out_dir: &'a Option<PathBuf>,
 460                                 out_file: &'a Option<PathBuf>,
 461                                 arena: &'tcx DroplessArena,
 462                                 arenas: &'tcx GlobalArenas<'tcx>,
 463                                 cstore: &'a CStore,
 464                                 hir_map: &'a hir_map::Map<'tcx>,
 465                                 analysis: &'a ty::CrateAnalysis,
 466                                 resolutions: &'a Resolutions,
 467                                 krate: &'a ast::Crate,
 468                                 hir_crate: &'a hir::Crate,
 469                                 crate_name: &'a str)
 470                                 -> Self {
 471         CompileState {
 472             crate_name: Some(crate_name),
 473             arena: Some(arena),
 474             arenas: Some(arenas),
 475             cstore: Some(cstore),
 476             hir_map: Some(hir_map),
 477             analysis: Some(analysis),
 478             resolutions: Some(resolutions),
 479             expanded_crate: Some(krate),
 480             hir_crate: Some(hir_crate),
 481             out_file: out_file.as_ref().map(|s| &**s),
 482             ..CompileState::empty(input, session, out_dir)
 483         }
 484     }
 485
 486     fn state_after_analysis(input: &'a Input,
 487                             session: &'tcx Session,
 488                             out_dir: &'a Option<PathBuf>,
 489                             out_file: &'a Option<PathBuf>,
 490                             krate: Option<&'a ast::Crate>,
 491                             hir_crate: &'a hir::Crate,
 492                             analysis: &'a ty::CrateAnalysis,
 493                             tcx: TyCtxt<'a, 'tcx, 'tcx>,
 494                             crate_name: &'a str)
 495                             -> Self {
 496         CompileState {
 497             analysis: Some(analysis),
 498             tcx: Some(tcx),
 499             expanded_crate: krate,
 500             hir_crate: Some(hir_crate),
 501             crate_name: Some(crate_name),
 502             out_file: out_file.as_ref().map(|s| &**s),
 503             ..CompileState::empty(input, session, out_dir)
 504         }
 505     }
 506
 507     #[cfg(feature="llvm")]
 508     fn state_after_llvm(input: &'a Input,
 509                         session: &'tcx Session,
 510                         out_dir: &'a Option<PathBuf>,
 511                         out_file: &'a Option<PathBuf>,
 512                         trans: &'a trans::CrateTranslation)
 513                         -> Self {
 514         CompileState {
 515             trans: Some(trans),
 516             out_file: out_file.as_ref().map(|s| &**s),
 517             ..CompileState::empty(input, session, out_dir)
 518         }
 519     }
 520
 521     #[cfg(feature="llvm")]
 522     fn state_when_compilation_done(input: &'a Input,
 523                                    session: &'tcx Session,
 524                                    out_dir: &'a Option<PathBuf>,
 525                                    out_file: &'a Option<PathBuf>)
 526                                    -> Self {
 527         CompileState {
 528             out_file: out_file.as_ref().map(|s| &**s),
 529             ..CompileState::empty(input, session, out_dir)
 530         }
 531     }
 532 }
 533
 534 pub fn phase_1_parse_input<'a>(control: &CompileController,
 535                                sess: &'a Session,
 536                                input: &Input)
 537                                -> PResult<'a, ast::Crate> {
 538     sess.diagnostic().set_continue_after_error(control.continue_parse_after_error);
 539
 540     let krate = time(sess.time_passes(), "parsing", || {
 541         match *input {
 542             Input::File(ref file) => {
 543                 parse::parse_crate_from_file(file, &sess.parse_sess)
 544             }
 545             Input::Str { ref input, ref name } => {
 546                 parse::parse_crate_from_source_str(name.clone(), input.clone(), &sess.parse_sess)
 547             }
 548         }
 549     })?;
 550
 551     sess.diagnostic().set_continue_after_error(true);
 552
 553     if sess.opts.debugging_opts.ast_json_noexpand {
 554         println!("{}", json::as_json(&krate));
 555     }
 556
 557     if sess.opts.debugging_opts.input_stats {
 558         println!("Lines of code:             {}", sess.codemap().count_lines());
 559         println!("Pre-expansion node count:  {}", count_nodes(&krate));
 560     }
 561
 562     if let Some(ref s) = sess.opts.debugging_opts.show_span {
 563         syntax::show_span::run(sess.diagnostic(), s, &krate);
 564     }
 565
 566     if sess.opts.debugging_opts.hir_stats {
 567         hir_stats::print_ast_stats(&krate, "PRE EXPANSION AST STATS");
 568     }
 569
 570     Ok(krate)
 571 }
 572
 573 fn count_nodes(krate: &ast::Crate) -> usize {
 574     let mut counter = NodeCounter::new();
 575     visit::walk_crate(&mut counter, krate);
 576     counter.count
 577 }
 578
 579 // For continuing compilation after a parsed crate has been
 580 // modified
 581
 582 pub struct ExpansionResult {
 583     pub expanded_crate: ast::Crate,
 584     pub defs: hir_map::Definitions,
 585     pub analysis: ty::CrateAnalysis,
 586     pub resolutions: Resolutions,
 587     pub hir_forest: hir_map::Forest,
 588 }
 589
 590 /// Run the "early phases" of the compiler: initial `cfg` processing,
 591 /// loading compiler plugins (including those from `addl_plugins`),
 592 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 593 /// harness if one is to be provided, injection of a dependency on the
 594 /// standard library and prelude, and name resolution.
 595 ///
 596 /// Returns `None` if we're aborting after handling -W help.
 597 pub fn phase_2_configure_and_expand<F>(sess: &Session,
 598                                        cstore: &CStore,
 599                                        krate: ast::Crate,
 600                                        registry: Option<Registry>,
 601                                        crate_name: &str,
 602                                        addl_plugins: Option<Vec<String>>,
 603                                        make_glob_map: MakeGlobMap,
 604                                        after_expand: F)
 605                                        -> Result<ExpansionResult, CompileIncomplete>
 606     where F: FnOnce(&ast::Crate) -> CompileResult,
 607 {
 608     let time_passes = sess.time_passes();
 609
 610     let (mut krate, features) = syntax::config::features(krate, &sess.parse_sess, sess.opts.test);
 611     // these need to be set "early" so that expansion sees `quote` if enabled.
 612     *sess.features.borrow_mut() = features;
 613
 614     *sess.crate_types.borrow_mut() = collect_crate_types(sess, &krate.attrs);
 615     *sess.crate_disambiguator.borrow_mut() = Symbol::intern(&compute_crate_disambiguator(sess));
 616
 617     time(time_passes, "recursion limit", || {
 618         middle::recursion_limit::update_limits(sess, &krate);
 619     });
 620
 621     krate = time(time_passes, "crate injection", || {
 622         let alt_std_name = sess.opts.alt_std_name.clone();
 623         syntax::std_inject::maybe_inject_crates_ref(krate, alt_std_name)
 624     });
 625
 626     let mut addl_plugins = Some(addl_plugins);
 627     let registrars = time(time_passes, "plugin loading", || {
 628         plugin::load::load_plugins(sess,
 629                                    &cstore,
 630                                    &krate,
 631                                    crate_name,
 632                                    addl_plugins.take().unwrap())
 633     });
 634
 635     let mut registry = registry.unwrap_or(Registry::new(sess, krate.span));
 636
 637     time(time_passes, "plugin registration", || {
 638         if sess.features.borrow().rustc_diagnostic_macros {
 639             registry.register_macro("__diagnostic_used",
 640                                     diagnostics::plugin::expand_diagnostic_used);
 641             registry.register_macro("__register_diagnostic",
 642                                     diagnostics::plugin::expand_register_diagnostic);
 643             registry.register_macro("__build_diagnostic_array",
 644                                     diagnostics::plugin::expand_build_diagnostic_array);
 645         }
 646
 647         for registrar in registrars {
 648             registry.args_hidden = Some(registrar.args);
 649             (registrar.fun)(&mut registry);
 650         }
 651     });
 652
 653     let whitelisted_legacy_custom_derives = registry.take_whitelisted_custom_derives();
 654     let Registry { syntax_exts, early_lint_passes, late_lint_passes, lint_groups,
 655                    llvm_passes, attributes, .. } = registry;
 656
 657     sess.track_errors(|| {
 658         let mut ls = sess.lint_store.borrow_mut();
 659         for pass in early_lint_passes {
 660             ls.register_early_pass(Some(sess), true, pass);
 661         }
 662         for pass in late_lint_passes {
 663             ls.register_late_pass(Some(sess), true, pass);
 664         }
 665
 666         for (name, to) in lint_groups {
 667             ls.register_group(Some(sess), true, name, to);
 668         }
 669
 670         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
 671         *sess.plugin_attributes.borrow_mut() = attributes.clone();
 672     })?;
 673
 674     // Lint plugins are registered; now we can process command line flags.
 675     if sess.opts.describe_lints {
 676         super::describe_lints(&sess.lint_store.borrow(), true);
 677         return Err(CompileIncomplete::Stopped);
 678     }
 679
 680     // Currently, we ignore the name resolution data structures for the purposes of dependency
 681     // tracking. Instead we will run name resolution and include its output in the hash of each
 682     // item, much like we do for macro expansion. In other words, the hash reflects not just
 683     // its contents but the results of name resolution on those contents. Hopefully we'll push
 684     // this back at some point.
 685     let _ignore = sess.dep_graph.in_ignore();
 686     let mut crate_loader = CrateLoader::new(sess, &cstore, crate_name);
 687     crate_loader.preprocess(&krate);
 688     let resolver_arenas = Resolver::arenas();
 689     let mut resolver = Resolver::new(sess,
 690                                      &krate,
 691                                      crate_name,
 692                                      make_glob_map,
 693                                      &mut crate_loader,
 694                                      &resolver_arenas);
 695     resolver.whitelisted_legacy_custom_derives = whitelisted_legacy_custom_derives;
 696     syntax_ext::register_builtins(&mut resolver, syntax_exts, sess.features.borrow().quote);
 697
 698     krate = time(time_passes, "expansion", || {
 699         // Windows dlls do not have rpaths, so they don't know how to find their
 700         // dependencies. It's up to us to tell the system where to find all the
 701         // dependent dlls. Note that this uses cfg!(windows) as opposed to
 702         // targ_cfg because syntax extensions are always loaded for the host
 703         // compiler, not for the target.
 704         //
 705         // This is somewhat of an inherently racy operation, however, as
 706         // multiple threads calling this function could possibly continue
 707         // extending PATH far beyond what it should. To solve this for now we
 708         // just don't add any new elements to PATH which are already there
 709         // within PATH. This is basically a targeted fix at #17360 for rustdoc
 710         // which runs rustc in parallel but has been seen (#33844) to cause
 711         // problems with PATH becoming too long.
 712         let mut old_path = OsString::new();
 713         if cfg!(windows) {
 714             old_path = env::var_os("PATH").unwrap_or(old_path);
 715             let mut new_path = sess.host_filesearch(PathKind::All)
 716                                    .get_dylib_search_paths();
 717             for path in env::split_paths(&old_path) {
 718                 if !new_path.contains(&path) {
 719                     new_path.push(path);
 720                 }
 721             }
 722             env::set_var("PATH",
 723                 &env::join_paths(new_path.iter()
 724                                          .filter(|p| env::join_paths(iter::once(p)).is_ok()))
 725                      .unwrap());
 726         }
 727         let features = sess.features.borrow();
 728         let cfg = syntax::ext::expand::ExpansionConfig {
 729             features: Some(&features),
 730             recursion_limit: sess.recursion_limit.get(),
 731             trace_mac: sess.opts.debugging_opts.trace_macros,
 732             should_test: sess.opts.test,
 733             ..syntax::ext::expand::ExpansionConfig::default(crate_name.to_string())
 734         };
 735
 736         let mut ecx = ExtCtxt::new(&sess.parse_sess, cfg, &mut resolver);
 737         let err_count = ecx.parse_sess.span_diagnostic.err_count();
 738
 739         let krate = ecx.monotonic_expander().expand_crate(krate);
 740
 741         ecx.check_unused_macros();
 742
 743         let mut missing_fragment_specifiers: Vec<_> =
 744             ecx.parse_sess.missing_fragment_specifiers.borrow().iter().cloned().collect();
 745         missing_fragment_specifiers.sort();
 746         for span in missing_fragment_specifiers {
 747             let lint = lint::builtin::MISSING_FRAGMENT_SPECIFIER;
 748             let msg = "missing fragment specifier";
 749             sess.buffer_lint(lint, ast::CRATE_NODE_ID, span, msg);
 750         }
 751         if ecx.parse_sess.span_diagnostic.err_count() - ecx.resolve_err_count > err_count {
 752             ecx.parse_sess.span_diagnostic.abort_if_errors();
 753         }
 754         if cfg!(windows) {
 755             env::set_var("PATH", &old_path);
 756         }
 757         krate
 758     });
 759
 760     krate = time(time_passes, "maybe building test harness", || {
 761         syntax::test::modify_for_testing(&sess.parse_sess,
 762                                          &mut resolver,
 763                                          sess.opts.test,
 764                                          krate,
 765                                          sess.diagnostic())
 766     });
 767
 768     // If we're in rustdoc we're always compiling as an rlib, but that'll trip a
 769     // bunch of checks in the `modify` function below. For now just skip this
 770     // step entirely if we're rustdoc as it's not too useful anyway.
 771     if !sess.opts.actually_rustdoc {
 772         krate = time(time_passes, "maybe creating a macro crate", || {
 773             let crate_types = sess.crate_types.borrow();
 774             let num_crate_types = crate_types.len();
 775             let is_proc_macro_crate = crate_types.contains(&config::CrateTypeProcMacro);
 776             let is_test_crate = sess.opts.test;
 777             syntax_ext::proc_macro_registrar::modify(&sess.parse_sess,
 778                                                      &mut resolver,
 779                                                      krate,
 780                                                      is_proc_macro_crate,
 781                                                      is_test_crate,
 782                                                      num_crate_types,
 783                                                      sess.diagnostic())
 784         });
 785     }
 786
 787     krate = time(time_passes, "creating allocators", || {
 788         allocator::expand::modify(&sess.parse_sess,
 789                                   &mut resolver,
 790                                   krate,
 791                                   sess.diagnostic())
 792     });
 793
 794     after_expand(&krate)?;
 795
 796     if sess.opts.debugging_opts.input_stats {
 797         println!("Post-expansion node count: {}", count_nodes(&krate));
 798     }
 799
 800     if sess.opts.debugging_opts.hir_stats {
 801         hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS");
 802     }
 803
 804     if sess.opts.debugging_opts.ast_json {
 805         println!("{}", json::as_json(&krate));
 806     }
 807
 808     time(time_passes,
 809          "checking for inline asm in case the target doesn't support it",
 810          || no_asm::check_crate(sess, &krate));
 811
 812     time(time_passes,
 813          "AST validation",
 814          || ast_validation::check_crate(sess, &krate));
 815
 816     time(time_passes, "name resolution", || -> CompileResult {
 817         resolver.resolve_crate(&krate);
 818         Ok(())
 819     })?;
 820
 821     if resolver.found_unresolved_macro {
 822         sess.parse_sess.span_diagnostic.abort_if_errors();
 823     }
 824
 825     // Needs to go *after* expansion to be able to check the results of macro expansion.
 826     time(time_passes, "complete gated feature checking", || {
 827         sess.track_errors(|| {
 828             syntax::feature_gate::check_crate(&krate,
 829                                               &sess.parse_sess,
 830                                               &sess.features.borrow(),
 831                                               &attributes,
 832                                               sess.opts.unstable_features);
 833         })
 834     })?;
 835
 836     time(time_passes,
 837          "early lint checks",
 838          || lint::check_ast_crate(sess, &krate));
 839
 840     // Lower ast -> hir.
 841     let hir_forest = time(time_passes, "lowering ast -> hir", || {
 842         let hir_crate = lower_crate(sess, &krate, &mut resolver);
 843
 844         if sess.opts.debugging_opts.hir_stats {
 845             hir_stats::print_hir_stats(&hir_crate);
 846         }
 847
 848         hir_map::Forest::new(hir_crate, &sess.dep_graph)
 849     });
 850
 851     // Discard hygiene data, which isn't required after lowering to HIR.
 852     if !keep_hygiene_data(sess) {
 853         syntax::ext::hygiene::clear_markings();
 854     }
 855
 856     Ok(ExpansionResult {
 857         expanded_crate: krate,
 858         defs: resolver.definitions,
 859         analysis: ty::CrateAnalysis {
 860             access_levels: Rc::new(AccessLevels::default()),
 861             reachable: Rc::new(NodeSet()),
 862             name: crate_name.to_string(),
 863             glob_map: if resolver.make_glob_map { Some(resolver.glob_map) } else { None },
 864         },
 865         resolutions: Resolutions {
 866             freevars: resolver.freevars,
 867             export_map: resolver.export_map,
 868             trait_map: resolver.trait_map,
 869             maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
 870         },
 871         hir_forest: hir_forest,
 872     })
 873 }
 874
 875 /// Run the resolution, typechecking, region checking and other
 876 /// miscellaneous analysis passes on the crate. Return various
 877 /// structures carrying the results of the analysis.
 878 pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 879                                                hir_map: hir_map::Map<'tcx>,
 880                                                mut analysis: ty::CrateAnalysis,
 881                                                resolutions: Resolutions,
 882                                                arena: &'tcx DroplessArena,
 883                                                arenas: &'tcx GlobalArenas<'tcx>,
 884                                                name: &str,
 885                                                f: F)
 886                                                -> Result<R, CompileIncomplete>
 887     where F: for<'a> FnOnce(TyCtxt<'a, 'tcx, 'tcx>,
 888                             ty::CrateAnalysis,
 889                             IncrementalHashesMap,
 890                             CompileResult) -> R
 891 {
 892     macro_rules! try_with_f {
 893         ($e: expr, ($t: expr, $a: expr, $h: expr)) => {
 894             match $e {
 895                 Ok(x) => x,
 896                 Err(x) => {
 897                     f($t, $a, $h, Err(x));
 898                     return Err(x);
 899                 }
 900             }
 901         }
 902     }
 903
 904     let time_passes = sess.time_passes();
 905
 906     let lang_items = time(time_passes, "language item collection", || {
 907         sess.track_errors(|| {
 908             middle::lang_items::collect_language_items(&sess, &hir_map)
 909         })
 910     })?;
 911
 912     let named_region_map = time(time_passes,
 913                                 "lifetime resolution",
 914                                 || middle::resolve_lifetime::krate(sess, &hir_map))?;
 915
 916     time(time_passes,
 917          "looking for entry point",
 918          || middle::entry::find_entry_point(sess, &hir_map));
 919
 920     sess.plugin_registrar_fn.set(time(time_passes, "looking for plugin registrar", || {
 921         plugin::build::find_plugin_registrar(sess.diagnostic(), &hir_map)
 922     }));
 923     sess.derive_registrar_fn.set(derive_registrar::find(&hir_map));
 924
 925     time(time_passes,
 926          "loop checking",
 927          || loops::check_crate(sess, &hir_map));
 928
 929     time(time_passes,
 930               "static item recursion checking",
 931               || static_recursion::check_crate(sess, &hir_map))?;
 932
 933     let index = stability::Index::new(&sess);
 934
 935     let mut local_providers = ty::maps::Providers::default();
 936     borrowck::provide(&mut local_providers);
 937     mir::provide(&mut local_providers);
 938     reachable::provide(&mut local_providers);
 939     rustc_privacy::provide(&mut local_providers);
 940     trans::provide(&mut local_providers);
 941     typeck::provide(&mut local_providers);
 942     ty::provide(&mut local_providers);
 943     traits::provide(&mut local_providers);
 944     reachable::provide(&mut local_providers);
 945     rustc_const_eval::provide(&mut local_providers);
 946     middle::region::provide(&mut local_providers);
 947     cstore::provide_local(&mut local_providers);
 948     lint::provide(&mut local_providers);
 949
 950     let mut extern_providers = ty::maps::Providers::default();
 951     cstore::provide(&mut extern_providers);
 952     trans::provide(&mut extern_providers);
 953     ty::provide_extern(&mut extern_providers);
 954     traits::provide_extern(&mut extern_providers);
 955     // FIXME(eddyb) get rid of this once we replace const_eval with miri.
 956     rustc_const_eval::provide(&mut extern_providers);
 957
 958     // Setup the MIR passes that we want to run.
 959     let mut passes = Passes::new();
 960     passes.push_hook(mir::transform::dump_mir::DumpMir);
 961
 962     // Remove all `EndRegion` statements that are not involved in borrows.
 963     passes.push_pass(MIR_CONST, mir::transform::clean_end_regions::CleanEndRegions);
 964
 965     // What we need to do constant evaluation.
 966     passes.push_pass(MIR_CONST, mir::transform::simplify::SimplifyCfg::new("initial"));
 967     passes.push_pass(MIR_CONST, mir::transform::type_check::TypeckMir);
 968     passes.push_pass(MIR_CONST, mir::transform::rustc_peek::SanityCheck);
 969
 970     // We compute "constant qualifications" betwen MIR_CONST and MIR_VALIDATED.
 971
 972     // What we need to run borrowck etc.
 973     passes.push_pass(MIR_VALIDATED, mir::transform::qualify_consts::QualifyAndPromoteConstants);
 974     passes.push_pass(MIR_VALIDATED,
 975                      mir::transform::simplify_branches::SimplifyBranches::new("initial"));
 976     passes.push_pass(MIR_VALIDATED, mir::transform::simplify::SimplifyCfg::new("qualify-consts"));
 977     passes.push_pass(MIR_VALIDATED, mir::transform::nll::NLL);
 978
 979     // borrowck runs between MIR_VALIDATED and MIR_OPTIMIZED.
 980
 981     // These next passes must be executed together
 982     passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads);
 983     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::CriticalCallEdges);
 984     passes.push_pass(MIR_OPTIMIZED, mir::transform::elaborate_drops::ElaborateDrops);
 985     passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads);
 986     // AddValidation needs to run after ElaborateDrops and before EraseRegions, and it needs
 987     // an AllCallEdges pass right before it.
 988     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::AllCallEdges);
 989     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_validation::AddValidation);
 990     passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyCfg::new("elaborate-drops"));
 991     // No lifetime analysis based on borrowing can be done from here on out.
 992
 993     // From here on out, regions are gone.
 994     passes.push_pass(MIR_OPTIMIZED, mir::transform::erase_regions::EraseRegions);
 995
 996     // Optimizations begin.
 997     passes.push_pass(MIR_OPTIMIZED, mir::transform::inline::Inline);
 998     passes.push_pass(MIR_OPTIMIZED, mir::transform::instcombine::InstCombine);
 999     passes.push_pass(MIR_OPTIMIZED, mir::transform::deaggregator::Deaggregator);
1000     passes.push_pass(MIR_OPTIMIZED, mir::transform::copy_prop::CopyPropagation);
1001     passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyLocals);
1002     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::CriticalCallEdges);
1003     passes.push_pass(MIR_OPTIMIZED, mir::transform::dump_mir::Marker("PreTrans"));
1004
1005     TyCtxt::create_and_enter(sess,
1006                              local_providers,
1007                              extern_providers,
1008                              Rc::new(passes),
1009                              arenas,
1010                              arena,
1011                              resolutions,
1012                              named_region_map,
1013                              hir_map,
1014                              lang_items,
1015                              index,
1016                              name,
1017                              |tcx| {
1018         let incremental_hashes_map =
1019             time(time_passes,
1020                  "compute_incremental_hashes_map",
1021                  || rustc_incremental::compute_incremental_hashes_map(tcx));
1022
1023         time(time_passes,
1024              "load_dep_graph",
1025              || rustc_incremental::load_dep_graph(tcx, &incremental_hashes_map));
1026
1027         time(time_passes, "stability index", || {
1028             tcx.stability.borrow_mut().build(tcx)
1029         });
1030
1031         time(time_passes,
1032              "stability checking",
1033              || stability::check_unstable_api_usage(tcx));
1034
1035         // passes are timed inside typeck
1036         try_with_f!(typeck::check_crate(tcx), (tcx, analysis, incremental_hashes_map));
1037
1038         time(time_passes,
1039              "const checking",
1040              || consts::check_crate(tcx));
1041
1042         analysis.access_levels =
1043             time(time_passes, "privacy checking", || rustc_privacy::check_crate(tcx));
1044
1045         time(time_passes,
1046              "intrinsic checking",
1047              || middle::intrinsicck::check_crate(tcx));
1048
1049         time(time_passes,
1050              "effect checking",
1051              || middle::effect::check_crate(tcx));
1052
1053         time(time_passes,
1054              "match checking",
1055              || check_match::check_crate(tcx));
1056
1057         // this must run before MIR dump, because
1058         // "not all control paths return a value" is reported here.
1059         //
1060         // maybe move the check to a MIR pass?
1061         time(time_passes,
1062              "liveness checking",
1063              || middle::liveness::check_crate(tcx));
1064
1065         time(time_passes,
1066              "borrow checking",
1067              || borrowck::check_crate(tcx));
1068
1069         // Avoid overwhelming user with errors if type checking failed.
1070         // I'm not sure how helpful this is, to be honest, but it avoids
1071         // a
1072         // lot of annoying errors in the compile-fail tests (basically,
1073         // lint warnings and so on -- kindck used to do this abort, but
1074         // kindck is gone now). -nmatsakis
1075         if sess.err_count() > 0 {
1076             return Ok(f(tcx, analysis, incremental_hashes_map, sess.compile_status()));
1077         }
1078
1079         analysis.reachable =
1080             time(time_passes,
1081                  "reachability checking",
1082                  || reachable::find_reachable(tcx));
1083
1084         time(time_passes, "death checking", || middle::dead::check_crate(tcx));
1085
1086         time(time_passes, "unused lib feature checking", || {
1087             stability::check_unused_or_stable_features(tcx)
1088         });
1089
1090         time(time_passes, "lint checking", || lint::check_crate(tcx));
1091
1092         return Ok(f(tcx, analysis, incremental_hashes_map, tcx.sess.compile_status()));
1093     })
1094 }
1095
1096 /// Run the translation phase to LLVM, after which the AST and analysis can
1097 /// be discarded.
1098 #[cfg(feature="llvm")]
1099 pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1100                                            analysis: ty::CrateAnalysis,
1101                                            incremental_hashes_map: IncrementalHashesMap,
1102                                            output_filenames: &OutputFilenames)
1103                                            -> write::OngoingCrateTranslation {
1104     let time_passes = tcx.sess.time_passes();
1105
1106     time(time_passes,
1107          "resolving dependency formats",
1108          || dependency_format::calculate(tcx));
1109
1110     let translation =
1111         time(time_passes,
1112              "translation",
1113              move || trans::trans_crate(tcx, analysis, incremental_hashes_map, output_filenames));
1114
1115     translation
1116 }
1117
1118 /// Run LLVM itself, producing a bitcode file, assembly file or object file
1119 /// as a side effect.
1120 #[cfg(feature="llvm")]
1121 pub fn phase_5_run_llvm_passes(sess: &Session,
1122                                trans: write::OngoingCrateTranslation)
1123                                -> (CompileResult, trans::CrateTranslation) {
1124     let trans = trans.join(sess);
1125
1126     if sess.opts.debugging_opts.incremental_info {
1127         write::dump_incremental_data(&trans);
1128     }
1129
1130     time(sess.time_passes(),
1131          "serialize work products",
1132          move || rustc_incremental::save_work_products(sess));
1133
1134     (sess.compile_status(), trans)
1135 }
1136
1137 /// Run the linker on any artifacts that resulted from the LLVM run.
1138 /// This should produce either a finished executable or library.
1139 #[cfg(feature="llvm")]
1140 pub fn phase_6_link_output(sess: &Session,
1141                            trans: &trans::CrateTranslation,
1142                            outputs: &OutputFilenames) {
1143     time(sess.time_passes(),
1144          "linking",
1145          || link::link_binary(sess, trans, outputs, &trans.crate_name.as_str()));
1146 }
1147
1148 fn escape_dep_filename(filename: &str) -> String {
1149     // Apparently clang and gcc *only* escape spaces:
1150     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
1151     filename.replace(" ", "\\ ")
1152 }
1153
1154 fn write_out_deps(sess: &Session, outputs: &OutputFilenames, crate_name: &str) {
1155     let mut out_filenames = Vec::new();
1156     for output_type in sess.opts.output_types.keys() {
1157         let file = outputs.path(*output_type);
1158         match *output_type {
1159             OutputType::Exe => {
1160                 for output in sess.crate_types.borrow().iter() {
1161                     let p = ::rustc_trans_utils::link::filename_for_input(
1162                         sess,
1163                         *output,
1164                         crate_name,
1165                         outputs
1166                     );
1167                     out_filenames.push(p);
1168                 }
1169             }
1170             _ => {
1171                 out_filenames.push(file);
1172             }
1173         }
1174     }
1175
1176     // Write out dependency rules to the dep-info file if requested
1177     if !sess.opts.output_types.contains_key(&OutputType::DepInfo) {
1178         return;
1179     }
1180     let deps_filename = outputs.path(OutputType::DepInfo);
1181
1182     let result =
1183         (|| -> io::Result<()> {
1184             // Build a list of files used to compile the output and
1185             // write Makefile-compatible dependency rules
1186             let files: Vec<String> = sess.codemap()
1187                                          .files()
1188                                          .iter()
1189                                          .filter(|fmap| fmap.is_real_file())
1190                                          .filter(|fmap| !fmap.is_imported())
1191                                          .map(|fmap| escape_dep_filename(&fmap.name))
1192                                          .collect();
1193             let mut file = fs::File::create(&deps_filename)?;
1194             for path in &out_filenames {
1195                 write!(file, "{}: {}\n\n", path.display(), files.join(" "))?;
1196             }
1197
1198             // Emit a fake target for each input file to the compilation. This
1199             // prevents `make` from spitting out an error if a file is later
1200             // deleted. For more info see #28735
1201             for path in files {
1202                 writeln!(file, "{}:", path)?;
1203             }
1204             Ok(())
1205         })();
1206
1207     match result {
1208         Ok(()) => {}
1209         Err(e) => {
1210             sess.fatal(&format!("error writing dependencies to `{}`: {}",
1211                                 deps_filename.display(),
1212                                 e));
1213         }
1214     }
1215 }
1216
1217 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
1218     // Unconditionally collect crate types from attributes to make them used
1219     let attr_types: Vec<config::CrateType> =
1220         attrs.iter()
1221              .filter_map(|a| {
1222                  if a.check_name("crate_type") {
1223                      match a.value_str() {
1224                          Some(ref n) if *n == "rlib" => {
1225                              Some(config::CrateTypeRlib)
1226                          }
1227                          Some(ref n) if *n == "dylib" => {
1228                              Some(config::CrateTypeDylib)
1229                          }
1230                          Some(ref n) if *n == "cdylib" => {
1231                              Some(config::CrateTypeCdylib)
1232                          }
1233                          Some(ref n) if *n == "lib" => {
1234                              Some(config::default_lib_output())
1235                          }
1236                          Some(ref n) if *n == "staticlib" => {
1237                              Some(config::CrateTypeStaticlib)
1238                          }
1239                          Some(ref n) if *n == "proc-macro" => {
1240                              Some(config::CrateTypeProcMacro)
1241                          }
1242                          Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
1243                          Some(_) => {
1244                              session.buffer_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
1245                                                  ast::CRATE_NODE_ID,
1246                                                  a.span,
1247                                                  "invalid `crate_type` value");
1248                              None
1249                          }
1250                          _ => {
1251                              session.struct_span_err(a.span, "`crate_type` requires a value")
1252                                  .note("for example: `#![crate_type=\"lib\"]`")
1253                                  .emit();
1254                              None
1255                          }
1256                      }
1257                  } else {
1258                      None
1259                  }
1260              })
1261              .collect();
1262
1263     // If we're generating a test executable, then ignore all other output
1264     // styles at all other locations
1265     if session.opts.test {
1266         return vec![config::CrateTypeExecutable];
1267     }
1268
1269     // Only check command line flags if present. If no types are specified by
1270     // command line, then reuse the empty `base` Vec to hold the types that
1271     // will be found in crate attributes.
1272     let mut base = session.opts.crate_types.clone();
1273     if base.is_empty() {
1274         base.extend(attr_types);
1275         if base.is_empty() {
1276             base.push(::rustc_trans_utils::link::default_output_for_target(session));
1277         }
1278         base.sort();
1279         base.dedup();
1280     }
1281
1282     base.into_iter()
1283         .filter(|crate_type| {
1284             let res = !::rustc_trans_utils::link::invalid_output_for_target(session, *crate_type);
1285
1286             if !res {
1287                 session.warn(&format!("dropping unsupported crate type `{}` for target `{}`",
1288                                       *crate_type,
1289                                       session.opts.target_triple));
1290             }
1291
1292             res
1293         })
1294         .collect()
1295 }
1296
1297 pub fn compute_crate_disambiguator(session: &Session) -> String {
1298     use std::hash::Hasher;
1299
1300     // The crate_disambiguator is a 128 bit hash. The disambiguator is fed
1301     // into various other hashes quite a bit (symbol hashes, incr. comp. hashes,
1302     // debuginfo type IDs, etc), so we don't want it to be too wide. 128 bits
1303     // should still be safe enough to avoid collisions in practice.
1304     // FIXME(mw): It seems that the crate_disambiguator is used everywhere as
1305     //            a hex-string instead of raw bytes. We should really use the
1306     //            smaller representation.
1307     let mut hasher = StableHasher::<Fingerprint>::new();
1308
1309     let mut metadata = session.opts.cg.metadata.clone();
1310     // We don't want the crate_disambiguator to dependent on the order
1311     // -C metadata arguments, so sort them:
1312     metadata.sort();
1313     // Every distinct -C metadata value is only incorporated once:
1314     metadata.dedup();
1315
1316     hasher.write(b"metadata");
1317     for s in &metadata {
1318         // Also incorporate the length of a metadata string, so that we generate
1319         // different values for `-Cmetadata=ab -Cmetadata=c` and
1320         // `-Cmetadata=a -Cmetadata=bc`
1321         hasher.write_usize(s.len());
1322         hasher.write(s.as_bytes());
1323     }
1324
1325     // If this is an executable, add a special suffix, so that we don't get
1326     // symbol conflicts when linking against a library of the same name.
1327     let is_exe = session.crate_types.borrow().contains(&config::CrateTypeExecutable);
1328
1329     format!("{}{}", hasher.finish().to_hex(), if is_exe { "-exe" } else {""})
1330 }
1331
1332 pub fn build_output_filenames(input: &Input,
1333                               odir: &Option<PathBuf>,
1334                               ofile: &Option<PathBuf>,
1335                               attrs: &[ast::Attribute],
1336                               sess: &Session)
1337                               -> OutputFilenames {
1338     match *ofile {
1339         None => {
1340             // "-" as input file will cause the parser to read from stdin so we
1341             // have to make up a name
1342             // We want to toss everything after the final '.'
1343             let dirpath = match *odir {
1344                 Some(ref d) => d.clone(),
1345                 None => PathBuf::new(),
1346             };
1347
1348             // If a crate name is present, we use it as the link name
1349             let stem = sess.opts
1350                            .crate_name
1351                            .clone()
1352                            .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
1353                            .unwrap_or(input.filestem());
1354
1355             OutputFilenames {
1356                 out_directory: dirpath,
1357                 out_filestem: stem,
1358                 single_output_file: None,
1359                 extra: sess.opts.cg.extra_filename.clone(),
1360                 outputs: sess.opts.output_types.clone(),
1361             }
1362         }
1363
1364         Some(ref out_file) => {
1365             let unnamed_output_types = sess.opts
1366                                            .output_types
1367                                            .values()
1368                                            .filter(|a| a.is_none())
1369                                            .count();
1370             let ofile = if unnamed_output_types > 1 {
1371                 sess.warn("due to multiple output types requested, the explicitly specified \
1372                            output file name will be adapted for each output type");
1373                 None
1374             } else {
1375                 Some(out_file.clone())
1376             };
1377             if *odir != None {
1378                 sess.warn("ignoring --out-dir flag due to -o flag.");
1379             }
1380
1381             let cur_dir = Path::new("");
1382
1383             OutputFilenames {
1384                 out_directory: out_file.parent().unwrap_or(cur_dir).to_path_buf(),
1385                 out_filestem: out_file.file_stem()
1386                                       .unwrap_or(OsStr::new(""))
1387                                       .to_str()
1388                                       .unwrap()
1389                                       .to_string(),
1390                 single_output_file: ofile,
1391                 extra: sess.opts.cg.extra_filename.clone(),
1392                 outputs: sess.opts.output_types.clone(),
1393             }
1394         }
1395     }
1396 }