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 #![cfg_attr(not(feature="llvm"), allow(dead_code))]
  12
  13 use rustc::dep_graph::DepGraph;
  14 use rustc::hir::{self, map as hir_map};
  15 use rustc::hir::lowering::lower_crate;
  16 use rustc::ich::Fingerprint;
  17 use rustc_data_structures::stable_hasher::StableHasher;
  18 use rustc_mir as mir;
  19 use rustc::session::{Session, CompileResult};
  20 use rustc::session::CompileIncomplete;
  21 use rustc::session::config::{self, Input, OutputFilenames, OutputType};
  22 use rustc::session::search_paths::PathKind;
  23 use rustc::lint;
  24 use rustc::middle::{self, stability, reachable};
  25 use rustc::middle::cstore::CrateStore;
  26 use rustc::middle::privacy::AccessLevels;
  27 use rustc::mir::transform::{MIR_CONST, MIR_VALIDATED, MIR_OPTIMIZED, Passes};
  28 use rustc::ty::{self, TyCtxt, Resolutions, GlobalArenas};
  29 use rustc::traits;
  30 use rustc::util::common::{ErrorReported, time};
  31 use rustc::util::nodemap::NodeSet;
  32 use rustc_allocator as allocator;
  33 use rustc_borrowck as borrowck;
  34 use rustc_incremental::{self, IncrementalHashesMap};
  35 use rustc_resolve::{MakeGlobMap, Resolver};
  36 use rustc_metadata::creader::CrateLoader;
  37 use rustc_metadata::cstore::{self, CStore};
  38 use rustc_trans::back::write;
  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 use profile;
  70
  71 pub fn compile_input(sess: &Session,
  72                      cstore: &CStore,
  73                      input: &Input,
  74                      outdir: &Option<PathBuf>,
  75                      output: &Option<PathBuf>,
  76                      addl_plugins: Option<Vec<String>>,
  77                      control: &CompileController) -> CompileResult {
  78     use rustc_trans::back::write::OngoingCrateTranslation;
  79     macro_rules! controller_entry_point {
  80         ($point: ident, $tsess: expr, $make_state: expr, $phase_result: expr) => {{
  81             let state = &mut $make_state;
  82             let phase_result: &CompileResult = &$phase_result;
  83             if phase_result.is_ok() || control.$point.run_callback_on_error {
  84                 (control.$point.callback)(state);
  85             }
  86
  87             if control.$point.stop == Compilation::Stop {
  88                 // FIXME: shouldn't this return Err(CompileIncomplete::Stopped)
  89                 // if there are no errors?
  90                 return $tsess.compile_status();
  91             }
  92         }}
  93     }
  94
  95     if cfg!(not(feature="llvm")) {
  96         use rustc::session::config::CrateType;
  97         if !sess.opts.debugging_opts.no_trans && sess.opts.output_types.should_trans() {
  98             sess.err("LLVM is not supported by this rustc. Please use -Z no-trans to compile")
  99         }
 100
 101         if sess.opts.crate_types.iter().all(|&t|{
 102             t != CrateType::CrateTypeRlib && t != CrateType::CrateTypeExecutable
 103         }) && !sess.opts.crate_types.is_empty() {
 104             sess.err(
 105                 "LLVM is not supported by this rustc, so non rlib libraries are not supported"
 106             );
 107         }
 108
 109         sess.abort_if_errors();
 110     }
 111
 112     if sess.profile_queries() {
 113         profile::begin();
 114     }
 115
 116     // We need nested scopes here, because the intermediate results can keep
 117     // large chunks of memory alive and we want to free them as soon as
 118     // possible to keep the peak memory usage low
 119     let (outputs, trans, dep_graph): (OutputFilenames, OngoingCrateTranslation, DepGraph) = {
 120         let krate = match phase_1_parse_input(control, sess, input) {
 121             Ok(krate) => krate,
 122             Err(mut parse_error) => {
 123                 parse_error.emit();
 124                 return Err(CompileIncomplete::Errored(ErrorReported));
 125             }
 126         };
 127
 128         let (krate, registry) = {
 129             let mut compile_state = CompileState::state_after_parse(input,
 130                                                                     sess,
 131                                                                     outdir,
 132                                                                     output,
 133                                                                     krate,
 134                                                                     &cstore);
 135             controller_entry_point!(after_parse,
 136                                     sess,
 137                                     compile_state,
 138                                     Ok(()));
 139
 140             (compile_state.krate.unwrap(), compile_state.registry)
 141         };
 142
 143         let outputs = build_output_filenames(input, outdir, output, &krate.attrs, sess);
 144         let crate_name =
 145             ::rustc_trans_utils::link::find_crate_name(Some(sess), &krate.attrs, input);
 146         let ExpansionResult { expanded_crate, defs, analysis, resolutions, mut hir_forest } = {
 147             phase_2_configure_and_expand(
 148                 sess,
 149                 &cstore,
 150                 krate,
 151                 registry,
 152                 &crate_name,
 153                 addl_plugins,
 154                 control.make_glob_map,
 155                 |expanded_crate| {
 156                     let mut state = CompileState::state_after_expand(
 157                         input, sess, outdir, output, &cstore, expanded_crate, &crate_name,
 158                     );
 159                     controller_entry_point!(after_expand, sess, state, Ok(()));
 160                     Ok(())
 161                 }
 162             )?
 163         };
 164
 165         write_out_deps(sess, &outputs, &crate_name);
 166         if sess.opts.output_types.contains_key(&OutputType::DepInfo) &&
 167             sess.opts.output_types.keys().count() == 1 {
 168             return Ok(())
 169         }
 170
 171         let arena = DroplessArena::new();
 172         let arenas = GlobalArenas::new();
 173
 174         // Construct the HIR map
 175         let hir_map = time(sess.time_passes(),
 176                            "indexing hir",
 177                            || hir_map::map_crate(&mut hir_forest, defs));
 178
 179         {
 180             let _ignore = hir_map.dep_graph.in_ignore();
 181             controller_entry_point!(after_hir_lowering,
 182                                     sess,
 183                                     CompileState::state_after_hir_lowering(input,
 184                                                                   sess,
 185                                                                   outdir,
 186                                                                   output,
 187                                                                   &arena,
 188                                                                   &arenas,
 189                                                                   &cstore,
 190                                                                   &hir_map,
 191                                                                   &analysis,
 192                                                                   &resolutions,
 193                                                                   &expanded_crate,
 194                                                                   &hir_map.krate(),
 195                                                                   &crate_name),
 196                                     Ok(()));
 197         }
 198
 199         time(sess.time_passes(), "attribute checking", || {
 200             hir::check_attr::check_crate(sess, &expanded_crate);
 201         });
 202
 203         let opt_crate = if control.keep_ast {
 204             Some(&expanded_crate)
 205         } else {
 206             drop(expanded_crate);
 207             None
 208         };
 209
 210         phase_3_run_analysis_passes(sess,
 211                                     cstore,
 212                                     hir_map,
 213                                     analysis,
 214                                     resolutions,
 215                                     &arena,
 216                                     &arenas,
 217                                     &crate_name,
 218                                     |tcx, analysis, incremental_hashes_map, result| {
 219             {
 220                 // Eventually, we will want to track plugins.
 221                 let _ignore = tcx.dep_graph.in_ignore();
 222
 223                 let mut state = CompileState::state_after_analysis(input,
 224                                                                    sess,
 225                                                                    outdir,
 226                                                                    output,
 227                                                                    opt_crate,
 228                                                                    tcx.hir.krate(),
 229                                                                    &analysis,
 230                                                                    tcx,
 231                                                                    &crate_name);
 232                 (control.after_analysis.callback)(&mut state);
 233
 234                 if control.after_analysis.stop == Compilation::Stop {
 235                     return result.and_then(|_| Err(CompileIncomplete::Stopped));
 236                 }
 237             }
 238
 239             result?;
 240
 241             if log_enabled!(::log::LogLevel::Info) {
 242                 println!("Pre-trans");
 243                 tcx.print_debug_stats();
 244             }
 245
 246             let trans = phase_4_translate_to_llvm(tcx, analysis, incremental_hashes_map,
 247                                                   &outputs);
 248
 249             if log_enabled!(::log::LogLevel::Info) {
 250                 println!("Post-trans");
 251                 tcx.print_debug_stats();
 252             }
 253
 254             if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
 255                 if let Err(e) = mir::transform::dump_mir::emit_mir(tcx, &outputs) {
 256                     sess.err(&format!("could not emit MIR: {}", e));
 257                     sess.abort_if_errors();
 258                 }
 259             }
 260
 261             Ok((outputs, trans, tcx.dep_graph.clone()))
 262         })??
 263     };
 264
 265     if cfg!(not(feature="llvm")) {
 266         let (_, _) = (outputs, trans);
 267         sess.fatal("LLVM is not supported by this rustc");
 268     }
 269
 270     #[cfg(feature="llvm")]
 271     {
 272         if sess.opts.debugging_opts.print_type_sizes {
 273             sess.code_stats.borrow().print_type_sizes();
 274         }
 275
 276         let (phase5_result, trans) = phase_5_run_llvm_passes(sess, &dep_graph, trans);
 277
 278         controller_entry_point!(after_llvm,
 279                                 sess,
 280                                 CompileState::state_after_llvm(input, sess, outdir, output, &trans),
 281                                 phase5_result);
 282         phase5_result?;
 283
 284         phase_6_link_output(sess, &trans, &outputs);
 285
 286         // Now that we won't touch anything in the incremental compilation directory
 287         // any more, we can finalize it (which involves renaming it)
 288         rustc_incremental::finalize_session_directory(sess, trans.link.crate_hash);
 289
 290         if sess.opts.debugging_opts.perf_stats {
 291             sess.print_perf_stats();
 292         }
 293
 294         controller_entry_point!(
 295             compilation_done,
 296             sess,
 297             CompileState::state_when_compilation_done(input, sess, outdir, output),
 298             Ok(())
 299         );
 300
 301         Ok(())
 302     }
 303 }
 304
 305 fn keep_hygiene_data(sess: &Session) -> bool {
 306     sess.opts.debugging_opts.keep_hygiene_data
 307 }
 308
 309
 310 /// The name used for source code that doesn't originate in a file
 311 /// (e.g. source from stdin or a string)
 312 pub fn anon_src() -> String {
 313     "<anon>".to_string()
 314 }
 315
 316 pub fn source_name(input: &Input) -> String {
 317     match *input {
 318         // FIXME (#9639): This needs to handle non-utf8 paths
 319         Input::File(ref ifile) => ifile.to_str().unwrap().to_string(),
 320         Input::Str { ref name, .. } => name.clone(),
 321     }
 322 }
 323
 324 /// CompileController is used to customize compilation, it allows compilation to
 325 /// be stopped and/or to call arbitrary code at various points in compilation.
 326 /// It also allows for various flags to be set to influence what information gets
 327 /// collected during compilation.
 328 ///
 329 /// This is a somewhat higher level controller than a Session - the Session
 330 /// controls what happens in each phase, whereas the CompileController controls
 331 /// whether a phase is run at all and whether other code (from outside the
 332 /// compiler) is run between phases.
 333 ///
 334 /// Note that if compilation is set to stop and a callback is provided for a
 335 /// given entry point, the callback is called before compilation is stopped.
 336 ///
 337 /// Expect more entry points to be added in the future.
 338 pub struct CompileController<'a> {
 339     pub after_parse: PhaseController<'a>,
 340     pub after_expand: PhaseController<'a>,
 341     pub after_hir_lowering: PhaseController<'a>,
 342     pub after_analysis: PhaseController<'a>,
 343     pub after_llvm: PhaseController<'a>,
 344     pub compilation_done: PhaseController<'a>,
 345
 346     // FIXME we probably want to group the below options together and offer a
 347     // better API, rather than this ad-hoc approach.
 348     pub make_glob_map: MakeGlobMap,
 349     // Whether the compiler should keep the ast beyond parsing.
 350     pub keep_ast: bool,
 351     // -Zcontinue-parse-after-error
 352     pub continue_parse_after_error: bool,
 353 }
 354
 355 impl<'a> CompileController<'a> {
 356     pub fn basic() -> CompileController<'a> {
 357         CompileController {
 358             after_parse: PhaseController::basic(),
 359             after_expand: PhaseController::basic(),
 360             after_hir_lowering: PhaseController::basic(),
 361             after_analysis: PhaseController::basic(),
 362             after_llvm: PhaseController::basic(),
 363             compilation_done: PhaseController::basic(),
 364             make_glob_map: MakeGlobMap::No,
 365             keep_ast: false,
 366             continue_parse_after_error: false,
 367         }
 368     }
 369 }
 370
 371 pub struct PhaseController<'a> {
 372     pub stop: Compilation,
 373     // If true then the compiler will try to run the callback even if the phase
 374     // ends with an error. Note that this is not always possible.
 375     pub run_callback_on_error: bool,
 376     pub callback: Box<Fn(&mut CompileState) + 'a>,
 377 }
 378
 379 impl<'a> PhaseController<'a> {
 380     pub fn basic() -> PhaseController<'a> {
 381         PhaseController {
 382             stop: Compilation::Continue,
 383             run_callback_on_error: false,
 384             callback: box |_| {},
 385         }
 386     }
 387 }
 388
 389 /// State that is passed to a callback. What state is available depends on when
 390 /// during compilation the callback is made. See the various constructor methods
 391 /// (`state_*`) in the impl to see which data is provided for any given entry point.
 392 pub struct CompileState<'a, 'tcx: 'a> {
 393     pub input: &'a Input,
 394     pub session: &'tcx Session,
 395     pub krate: Option<ast::Crate>,
 396     pub registry: Option<Registry<'a>>,
 397     pub cstore: Option<&'tcx CStore>,
 398     pub crate_name: Option<&'a str>,
 399     pub output_filenames: Option<&'a OutputFilenames>,
 400     pub out_dir: Option<&'a Path>,
 401     pub out_file: Option<&'a Path>,
 402     pub arena: Option<&'tcx DroplessArena>,
 403     pub arenas: Option<&'tcx GlobalArenas<'tcx>>,
 404     pub expanded_crate: Option<&'a ast::Crate>,
 405     pub hir_crate: Option<&'a hir::Crate>,
 406     pub hir_map: Option<&'a hir_map::Map<'tcx>>,
 407     pub resolutions: Option<&'a Resolutions>,
 408     pub analysis: Option<&'a ty::CrateAnalysis>,
 409     pub tcx: Option<TyCtxt<'a, 'tcx, 'tcx>>,
 410     pub trans: Option<&'a trans::CrateTranslation>,
 411 }
 412
 413 impl<'a, 'tcx> CompileState<'a, 'tcx> {
 414     fn empty(input: &'a Input,
 415              session: &'tcx Session,
 416              out_dir: &'a Option<PathBuf>)
 417              -> Self {
 418         CompileState {
 419             input,
 420             session,
 421             out_dir: out_dir.as_ref().map(|s| &**s),
 422             out_file: None,
 423             arena: None,
 424             arenas: None,
 425             krate: None,
 426             registry: None,
 427             cstore: None,
 428             crate_name: None,
 429             output_filenames: None,
 430             expanded_crate: None,
 431             hir_crate: None,
 432             hir_map: None,
 433             resolutions: None,
 434             analysis: None,
 435             tcx: None,
 436             trans: None,
 437         }
 438     }
 439
 440     fn state_after_parse(input: &'a Input,
 441                          session: &'tcx Session,
 442                          out_dir: &'a Option<PathBuf>,
 443                          out_file: &'a Option<PathBuf>,
 444                          krate: ast::Crate,
 445                          cstore: &'tcx CStore)
 446                          -> Self {
 447         CompileState {
 448             // Initialize the registry before moving `krate`
 449             registry: Some(Registry::new(&session, krate.span)),
 450             krate: Some(krate),
 451             cstore: Some(cstore),
 452             out_file: out_file.as_ref().map(|s| &**s),
 453             ..CompileState::empty(input, session, out_dir)
 454         }
 455     }
 456
 457     fn state_after_expand(input: &'a Input,
 458                           session: &'tcx Session,
 459                           out_dir: &'a Option<PathBuf>,
 460                           out_file: &'a Option<PathBuf>,
 461                           cstore: &'tcx CStore,
 462                           expanded_crate: &'a ast::Crate,
 463                           crate_name: &'a str)
 464                           -> Self {
 465         CompileState {
 466             crate_name: Some(crate_name),
 467             cstore: Some(cstore),
 468             expanded_crate: Some(expanded_crate),
 469             out_file: out_file.as_ref().map(|s| &**s),
 470             ..CompileState::empty(input, session, out_dir)
 471         }
 472     }
 473
 474     fn state_after_hir_lowering(input: &'a Input,
 475                                 session: &'tcx Session,
 476                                 out_dir: &'a Option<PathBuf>,
 477                                 out_file: &'a Option<PathBuf>,
 478                                 arena: &'tcx DroplessArena,
 479                                 arenas: &'tcx GlobalArenas<'tcx>,
 480                                 cstore: &'tcx CStore,
 481                                 hir_map: &'a hir_map::Map<'tcx>,
 482                                 analysis: &'a ty::CrateAnalysis,
 483                                 resolutions: &'a Resolutions,
 484                                 krate: &'a ast::Crate,
 485                                 hir_crate: &'a hir::Crate,
 486                                 crate_name: &'a str)
 487                                 -> Self {
 488         CompileState {
 489             crate_name: Some(crate_name),
 490             arena: Some(arena),
 491             arenas: Some(arenas),
 492             cstore: Some(cstore),
 493             hir_map: Some(hir_map),
 494             analysis: Some(analysis),
 495             resolutions: Some(resolutions),
 496             expanded_crate: Some(krate),
 497             hir_crate: Some(hir_crate),
 498             out_file: out_file.as_ref().map(|s| &**s),
 499             ..CompileState::empty(input, session, out_dir)
 500         }
 501     }
 502
 503     fn state_after_analysis(input: &'a Input,
 504                             session: &'tcx Session,
 505                             out_dir: &'a Option<PathBuf>,
 506                             out_file: &'a Option<PathBuf>,
 507                             krate: Option<&'a ast::Crate>,
 508                             hir_crate: &'a hir::Crate,
 509                             analysis: &'a ty::CrateAnalysis,
 510                             tcx: TyCtxt<'a, 'tcx, 'tcx>,
 511                             crate_name: &'a str)
 512                             -> Self {
 513         CompileState {
 514             analysis: Some(analysis),
 515             tcx: Some(tcx),
 516             expanded_crate: krate,
 517             hir_crate: Some(hir_crate),
 518             crate_name: Some(crate_name),
 519             out_file: out_file.as_ref().map(|s| &**s),
 520             ..CompileState::empty(input, session, out_dir)
 521         }
 522     }
 523
 524     fn state_after_llvm(input: &'a Input,
 525                         session: &'tcx Session,
 526                         out_dir: &'a Option<PathBuf>,
 527                         out_file: &'a Option<PathBuf>,
 528                         trans: &'a trans::CrateTranslation)
 529                         -> Self {
 530         CompileState {
 531             trans: Some(trans),
 532             out_file: out_file.as_ref().map(|s| &**s),
 533             ..CompileState::empty(input, session, out_dir)
 534         }
 535     }
 536
 537     fn state_when_compilation_done(input: &'a Input,
 538                                    session: &'tcx Session,
 539                                    out_dir: &'a Option<PathBuf>,
 540                                    out_file: &'a Option<PathBuf>)
 541                                    -> Self {
 542         CompileState {
 543             out_file: out_file.as_ref().map(|s| &**s),
 544             ..CompileState::empty(input, session, out_dir)
 545         }
 546     }
 547 }
 548
 549 pub fn phase_1_parse_input<'a>(control: &CompileController,
 550                                sess: &'a Session,
 551                                input: &Input)
 552                                -> PResult<'a, ast::Crate> {
 553     sess.diagnostic().set_continue_after_error(control.continue_parse_after_error);
 554
 555     if sess.profile_queries() {
 556         profile::begin();
 557     }
 558
 559     let krate = time(sess.time_passes(), "parsing", || {
 560         match *input {
 561             Input::File(ref file) => {
 562                 parse::parse_crate_from_file(file, &sess.parse_sess)
 563             }
 564             Input::Str { ref input, ref name } => {
 565                 parse::parse_crate_from_source_str(name.clone(), input.clone(), &sess.parse_sess)
 566             }
 567         }
 568     })?;
 569
 570     sess.diagnostic().set_continue_after_error(true);
 571
 572     if sess.opts.debugging_opts.ast_json_noexpand {
 573         println!("{}", json::as_json(&krate));
 574     }
 575
 576     if sess.opts.debugging_opts.input_stats {
 577         println!("Lines of code:             {}", sess.codemap().count_lines());
 578         println!("Pre-expansion node count:  {}", count_nodes(&krate));
 579     }
 580
 581     if let Some(ref s) = sess.opts.debugging_opts.show_span {
 582         syntax::show_span::run(sess.diagnostic(), s, &krate);
 583     }
 584
 585     if sess.opts.debugging_opts.hir_stats {
 586         hir_stats::print_ast_stats(&krate, "PRE EXPANSION AST STATS");
 587     }
 588
 589     Ok(krate)
 590 }
 591
 592 fn count_nodes(krate: &ast::Crate) -> usize {
 593     let mut counter = NodeCounter::new();
 594     visit::walk_crate(&mut counter, krate);
 595     counter.count
 596 }
 597
 598 // For continuing compilation after a parsed crate has been
 599 // modified
 600
 601 pub struct ExpansionResult {
 602     pub expanded_crate: ast::Crate,
 603     pub defs: hir_map::Definitions,
 604     pub analysis: ty::CrateAnalysis,
 605     pub resolutions: Resolutions,
 606     pub hir_forest: hir_map::Forest,
 607 }
 608
 609 /// Run the "early phases" of the compiler: initial `cfg` processing,
 610 /// loading compiler plugins (including those from `addl_plugins`),
 611 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 612 /// harness if one is to be provided, injection of a dependency on the
 613 /// standard library and prelude, and name resolution.
 614 ///
 615 /// Returns `None` if we're aborting after handling -W help.
 616 pub fn phase_2_configure_and_expand<F>(sess: &Session,
 617                                        cstore: &CStore,
 618                                        krate: ast::Crate,
 619                                        registry: Option<Registry>,
 620                                        crate_name: &str,
 621                                        addl_plugins: Option<Vec<String>>,
 622                                        make_glob_map: MakeGlobMap,
 623                                        after_expand: F)
 624                                        -> Result<ExpansionResult, CompileIncomplete>
 625     where F: FnOnce(&ast::Crate) -> CompileResult,
 626 {
 627     let time_passes = sess.time_passes();
 628
 629     let (mut krate, features) = syntax::config::features(krate, &sess.parse_sess, sess.opts.test);
 630     // these need to be set "early" so that expansion sees `quote` if enabled.
 631     *sess.features.borrow_mut() = features;
 632
 633     *sess.crate_types.borrow_mut() = collect_crate_types(sess, &krate.attrs);
 634
 635     let disambiguator = Symbol::intern(&compute_crate_disambiguator(sess));
 636     *sess.crate_disambiguator.borrow_mut() = Some(disambiguator);
 637     rustc_incremental::prepare_session_directory(
 638         sess,
 639         &crate_name,
 640         &disambiguator.as_str(),
 641     );
 642     let dep_graph = DepGraph::new(sess.opts.build_dep_graph());
 643
 644     time(time_passes, "recursion limit", || {
 645         middle::recursion_limit::update_limits(sess, &krate);
 646     });
 647
 648     krate = time(time_passes, "crate injection", || {
 649         let alt_std_name = sess.opts.alt_std_name.clone();
 650         syntax::std_inject::maybe_inject_crates_ref(krate, alt_std_name)
 651     });
 652
 653     let mut addl_plugins = Some(addl_plugins);
 654     let registrars = time(time_passes, "plugin loading", || {
 655         plugin::load::load_plugins(sess,
 656                                    &cstore,
 657                                    &krate,
 658                                    crate_name,
 659                                    addl_plugins.take().unwrap())
 660     });
 661
 662     let mut registry = registry.unwrap_or(Registry::new(sess, krate.span));
 663
 664     time(time_passes, "plugin registration", || {
 665         if sess.features.borrow().rustc_diagnostic_macros {
 666             registry.register_macro("__diagnostic_used",
 667                                     diagnostics::plugin::expand_diagnostic_used);
 668             registry.register_macro("__register_diagnostic",
 669                                     diagnostics::plugin::expand_register_diagnostic);
 670             registry.register_macro("__build_diagnostic_array",
 671                                     diagnostics::plugin::expand_build_diagnostic_array);
 672         }
 673
 674         for registrar in registrars {
 675             registry.args_hidden = Some(registrar.args);
 676             (registrar.fun)(&mut registry);
 677         }
 678     });
 679
 680     let whitelisted_legacy_custom_derives = registry.take_whitelisted_custom_derives();
 681     let Registry { syntax_exts, early_lint_passes, late_lint_passes, lint_groups,
 682                    llvm_passes, attributes, .. } = registry;
 683
 684     sess.track_errors(|| {
 685         let mut ls = sess.lint_store.borrow_mut();
 686         for pass in early_lint_passes {
 687             ls.register_early_pass(Some(sess), true, pass);
 688         }
 689         for pass in late_lint_passes {
 690             ls.register_late_pass(Some(sess), true, pass);
 691         }
 692
 693         for (name, to) in lint_groups {
 694             ls.register_group(Some(sess), true, name, to);
 695         }
 696
 697         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
 698         *sess.plugin_attributes.borrow_mut() = attributes.clone();
 699     })?;
 700
 701     // Lint plugins are registered; now we can process command line flags.
 702     if sess.opts.describe_lints {
 703         super::describe_lints(&sess.lint_store.borrow(), true);
 704         return Err(CompileIncomplete::Stopped);
 705     }
 706
 707     // Currently, we ignore the name resolution data structures for the purposes of dependency
 708     // tracking. Instead we will run name resolution and include its output in the hash of each
 709     // item, much like we do for macro expansion. In other words, the hash reflects not just
 710     // its contents but the results of name resolution on those contents. Hopefully we'll push
 711     // this back at some point.
 712     let _ignore = dep_graph.in_ignore();
 713     let mut crate_loader = CrateLoader::new(sess, &cstore, crate_name);
 714     let resolver_arenas = Resolver::arenas();
 715     let mut resolver = Resolver::new(sess,
 716                                      cstore,
 717                                      &krate,
 718                                      crate_name,
 719                                      make_glob_map,
 720                                      &mut crate_loader,
 721                                      &resolver_arenas);
 722     resolver.whitelisted_legacy_custom_derives = whitelisted_legacy_custom_derives;
 723     syntax_ext::register_builtins(&mut resolver, syntax_exts, sess.features.borrow().quote);
 724
 725     krate = time(time_passes, "expansion", || {
 726         // Windows dlls do not have rpaths, so they don't know how to find their
 727         // dependencies. It's up to us to tell the system where to find all the
 728         // dependent dlls. Note that this uses cfg!(windows) as opposed to
 729         // targ_cfg because syntax extensions are always loaded for the host
 730         // compiler, not for the target.
 731         //
 732         // This is somewhat of an inherently racy operation, however, as
 733         // multiple threads calling this function could possibly continue
 734         // extending PATH far beyond what it should. To solve this for now we
 735         // just don't add any new elements to PATH which are already there
 736         // within PATH. This is basically a targeted fix at #17360 for rustdoc
 737         // which runs rustc in parallel but has been seen (#33844) to cause
 738         // problems with PATH becoming too long.
 739         let mut old_path = OsString::new();
 740         if cfg!(windows) {
 741             old_path = env::var_os("PATH").unwrap_or(old_path);
 742             let mut new_path = sess.host_filesearch(PathKind::All)
 743                                    .get_dylib_search_paths();
 744             for path in env::split_paths(&old_path) {
 745                 if !new_path.contains(&path) {
 746                     new_path.push(path);
 747                 }
 748             }
 749             env::set_var("PATH",
 750                 &env::join_paths(new_path.iter()
 751                                          .filter(|p| env::join_paths(iter::once(p)).is_ok()))
 752                      .unwrap());
 753         }
 754         let features = sess.features.borrow();
 755         let cfg = syntax::ext::expand::ExpansionConfig {
 756             features: Some(&features),
 757             recursion_limit: sess.recursion_limit.get(),
 758             trace_mac: sess.opts.debugging_opts.trace_macros,
 759             should_test: sess.opts.test,
 760             ..syntax::ext::expand::ExpansionConfig::default(crate_name.to_string())
 761         };
 762
 763         let mut ecx = ExtCtxt::new(&sess.parse_sess, cfg, &mut resolver);
 764         let err_count = ecx.parse_sess.span_diagnostic.err_count();
 765
 766         let krate = ecx.monotonic_expander().expand_crate(krate);
 767
 768         ecx.check_unused_macros();
 769
 770         let mut missing_fragment_specifiers: Vec<_> =
 771             ecx.parse_sess.missing_fragment_specifiers.borrow().iter().cloned().collect();
 772         missing_fragment_specifiers.sort();
 773         for span in missing_fragment_specifiers {
 774             let lint = lint::builtin::MISSING_FRAGMENT_SPECIFIER;
 775             let msg = "missing fragment specifier";
 776             sess.buffer_lint(lint, ast::CRATE_NODE_ID, span, msg);
 777         }
 778         if ecx.parse_sess.span_diagnostic.err_count() - ecx.resolve_err_count > err_count {
 779             ecx.parse_sess.span_diagnostic.abort_if_errors();
 780         }
 781         if cfg!(windows) {
 782             env::set_var("PATH", &old_path);
 783         }
 784         krate
 785     });
 786
 787     krate = time(time_passes, "maybe building test harness", || {
 788         syntax::test::modify_for_testing(&sess.parse_sess,
 789                                          &mut resolver,
 790                                          sess.opts.test,
 791                                          krate,
 792                                          sess.diagnostic())
 793     });
 794
 795     // If we're in rustdoc we're always compiling as an rlib, but that'll trip a
 796     // bunch of checks in the `modify` function below. For now just skip this
 797     // step entirely if we're rustdoc as it's not too useful anyway.
 798     if !sess.opts.actually_rustdoc {
 799         krate = time(time_passes, "maybe creating a macro crate", || {
 800             let crate_types = sess.crate_types.borrow();
 801             let num_crate_types = crate_types.len();
 802             let is_proc_macro_crate = crate_types.contains(&config::CrateTypeProcMacro);
 803             let is_test_crate = sess.opts.test;
 804             syntax_ext::proc_macro_registrar::modify(&sess.parse_sess,
 805                                                      &mut resolver,
 806                                                      krate,
 807                                                      is_proc_macro_crate,
 808                                                      is_test_crate,
 809                                                      num_crate_types,
 810                                                      sess.diagnostic())
 811         });
 812     }
 813
 814     krate = time(time_passes, "creating allocators", || {
 815         allocator::expand::modify(&sess.parse_sess,
 816                                   &mut resolver,
 817                                   krate,
 818                                   sess.diagnostic())
 819     });
 820
 821     after_expand(&krate)?;
 822
 823     if sess.opts.debugging_opts.input_stats {
 824         println!("Post-expansion node count: {}", count_nodes(&krate));
 825     }
 826
 827     if sess.opts.debugging_opts.hir_stats {
 828         hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS");
 829     }
 830
 831     if sess.opts.debugging_opts.ast_json {
 832         println!("{}", json::as_json(&krate));
 833     }
 834
 835     time(time_passes,
 836          "checking for inline asm in case the target doesn't support it",
 837          || no_asm::check_crate(sess, &krate));
 838
 839     time(time_passes,
 840          "AST validation",
 841          || ast_validation::check_crate(sess, &krate));
 842
 843     time(time_passes, "name resolution", || -> CompileResult {
 844         resolver.resolve_crate(&krate);
 845         Ok(())
 846     })?;
 847
 848     if resolver.found_unresolved_macro {
 849         sess.parse_sess.span_diagnostic.abort_if_errors();
 850     }
 851
 852     // Needs to go *after* expansion to be able to check the results of macro expansion.
 853     time(time_passes, "complete gated feature checking", || {
 854         sess.track_errors(|| {
 855             syntax::feature_gate::check_crate(&krate,
 856                                               &sess.parse_sess,
 857                                               &sess.features.borrow(),
 858                                               &attributes,
 859                                               sess.opts.unstable_features);
 860         })
 861     })?;
 862
 863     // Lower ast -> hir.
 864     let hir_forest = time(time_passes, "lowering ast -> hir", || {
 865         let hir_crate = lower_crate(sess, cstore, &dep_graph, &krate, &mut resolver);
 866
 867         if sess.opts.debugging_opts.hir_stats {
 868             hir_stats::print_hir_stats(&hir_crate);
 869         }
 870
 871         hir_map::Forest::new(hir_crate, &dep_graph)
 872     });
 873
 874     time(time_passes,
 875          "early lint checks",
 876          || lint::check_ast_crate(sess, &krate));
 877
 878     // Discard hygiene data, which isn't required after lowering to HIR.
 879     if !keep_hygiene_data(sess) {
 880         syntax::ext::hygiene::clear_markings();
 881     }
 882
 883     Ok(ExpansionResult {
 884         expanded_crate: krate,
 885         defs: resolver.definitions,
 886         analysis: ty::CrateAnalysis {
 887             access_levels: Rc::new(AccessLevels::default()),
 888             reachable: Rc::new(NodeSet()),
 889             name: crate_name.to_string(),
 890             glob_map: if resolver.make_glob_map { Some(resolver.glob_map) } else { None },
 891         },
 892         resolutions: Resolutions {
 893             freevars: resolver.freevars,
 894             export_map: resolver.export_map,
 895             trait_map: resolver.trait_map,
 896             maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
 897             maybe_unused_extern_crates: resolver.maybe_unused_extern_crates,
 898         },
 899         hir_forest,
 900     })
 901 }
 902
 903 /// Run the resolution, typechecking, region checking and other
 904 /// miscellaneous analysis passes on the crate. Return various
 905 /// structures carrying the results of the analysis.
 906 pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 907                                                cstore: &'tcx CrateStore,
 908                                                hir_map: hir_map::Map<'tcx>,
 909                                                mut analysis: ty::CrateAnalysis,
 910                                                resolutions: Resolutions,
 911                                                arena: &'tcx DroplessArena,
 912                                                arenas: &'tcx GlobalArenas<'tcx>,
 913                                                name: &str,
 914                                                f: F)
 915                                                -> Result<R, CompileIncomplete>
 916     where F: for<'a> FnOnce(TyCtxt<'a, 'tcx, 'tcx>,
 917                             ty::CrateAnalysis,
 918                             IncrementalHashesMap,
 919                             CompileResult) -> R
 920 {
 921     macro_rules! try_with_f {
 922         ($e: expr, ($t: expr, $a: expr, $h: expr)) => {
 923             match $e {
 924                 Ok(x) => x,
 925                 Err(x) => {
 926                     f($t, $a, $h, Err(x));
 927                     return Err(x);
 928                 }
 929             }
 930         }
 931     }
 932
 933     let time_passes = sess.time_passes();
 934
 935     let named_region_map = time(time_passes,
 936                                 "lifetime resolution",
 937                                 || middle::resolve_lifetime::krate(sess, cstore, &hir_map))?;
 938
 939     time(time_passes,
 940          "looking for entry point",
 941          || middle::entry::find_entry_point(sess, &hir_map));
 942
 943     sess.plugin_registrar_fn.set(time(time_passes, "looking for plugin registrar", || {
 944         plugin::build::find_plugin_registrar(sess.diagnostic(), &hir_map)
 945     }));
 946     sess.derive_registrar_fn.set(derive_registrar::find(&hir_map));
 947
 948     time(time_passes,
 949          "loop checking",
 950          || loops::check_crate(sess, &hir_map));
 951
 952     time(time_passes,
 953               "static item recursion checking",
 954               || static_recursion::check_crate(sess, &hir_map))?;
 955
 956     let mut local_providers = ty::maps::Providers::default();
 957     borrowck::provide(&mut local_providers);
 958     mir::provide(&mut local_providers);
 959     reachable::provide(&mut local_providers);
 960     rustc_privacy::provide(&mut local_providers);
 961     trans::provide(&mut local_providers);
 962     typeck::provide(&mut local_providers);
 963     ty::provide(&mut local_providers);
 964     traits::provide(&mut local_providers);
 965     reachable::provide(&mut local_providers);
 966     rustc_const_eval::provide(&mut local_providers);
 967     middle::region::provide(&mut local_providers);
 968     cstore::provide_local(&mut local_providers);
 969     lint::provide(&mut local_providers);
 970
 971     let mut extern_providers = ty::maps::Providers::default();
 972     cstore::provide(&mut extern_providers);
 973     trans::provide(&mut extern_providers);
 974     ty::provide_extern(&mut extern_providers);
 975     traits::provide_extern(&mut extern_providers);
 976     // FIXME(eddyb) get rid of this once we replace const_eval with miri.
 977     rustc_const_eval::provide(&mut extern_providers);
 978
 979     // Setup the MIR passes that we want to run.
 980     let mut passes = Passes::new();
 981     passes.push_hook(mir::transform::dump_mir::DumpMir);
 982
 983     // Remove all `EndRegion` statements that are not involved in borrows.
 984     passes.push_pass(MIR_CONST, mir::transform::clean_end_regions::CleanEndRegions);
 985
 986     // What we need to do constant evaluation.
 987     passes.push_pass(MIR_CONST, mir::transform::simplify::SimplifyCfg::new("initial"));
 988     passes.push_pass(MIR_CONST, mir::transform::type_check::TypeckMir);
 989     passes.push_pass(MIR_CONST, mir::transform::rustc_peek::SanityCheck);
 990
 991     // We compute "constant qualifications" between MIR_CONST and MIR_VALIDATED.
 992
 993     // What we need to run borrowck etc.
 994
 995     passes.push_pass(MIR_VALIDATED, mir::transform::qualify_consts::QualifyAndPromoteConstants);
 996
 997     // FIXME: ariel points SimplifyBranches should run after
 998     // mir-borrowck; otherwise code within `if false { ... }` would
 999     // not be checked.
1000     passes.push_pass(MIR_VALIDATED,
1001                      mir::transform::simplify_branches::SimplifyBranches::new("initial"));
1002     passes.push_pass(MIR_VALIDATED, mir::transform::simplify::SimplifyCfg::new("qualify-consts"));
1003     passes.push_pass(MIR_VALIDATED, mir::transform::nll::NLL);
1004
1005     // borrowck runs between MIR_VALIDATED and MIR_OPTIMIZED.
1006
1007     // These next passes must be executed together
1008     passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads);
1009     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::CriticalCallEdges);
1010     passes.push_pass(MIR_OPTIMIZED, mir::transform::elaborate_drops::ElaborateDrops);
1011     passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads);
1012     // AddValidation needs to run after ElaborateDrops and before EraseRegions, and it needs
1013     // an AllCallEdges pass right before it.
1014     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::AllCallEdges);
1015     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_validation::AddValidation);
1016     passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyCfg::new("elaborate-drops"));
1017     // No lifetime analysis based on borrowing can be done from here on out.
1018
1019     // From here on out, regions are gone.
1020     passes.push_pass(MIR_OPTIMIZED, mir::transform::erase_regions::EraseRegions);
1021
1022     // Optimizations begin.
1023     passes.push_pass(MIR_OPTIMIZED, mir::transform::inline::Inline);
1024     passes.push_pass(MIR_OPTIMIZED, mir::transform::instcombine::InstCombine);
1025     passes.push_pass(MIR_OPTIMIZED, mir::transform::deaggregator::Deaggregator);
1026     passes.push_pass(MIR_OPTIMIZED, mir::transform::copy_prop::CopyPropagation);
1027     passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyLocals);
1028
1029     passes.push_pass(MIR_OPTIMIZED, mir::transform::generator::StateTransform);
1030     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::CriticalCallEdges);
1031     passes.push_pass(MIR_OPTIMIZED, mir::transform::dump_mir::Marker("PreTrans"));
1032
1033     TyCtxt::create_and_enter(sess,
1034                              cstore,
1035                              local_providers,
1036                              extern_providers,
1037                              Rc::new(passes),
1038                              arenas,
1039                              arena,
1040                              resolutions,
1041                              named_region_map,
1042                              hir_map,
1043                              name,
1044                              |tcx| {
1045         let incremental_hashes_map =
1046             time(time_passes,
1047                  "compute_incremental_hashes_map",
1048                  || rustc_incremental::compute_incremental_hashes_map(tcx));
1049
1050         time(time_passes,
1051              "load_dep_graph",
1052              || rustc_incremental::load_dep_graph(tcx, &incremental_hashes_map));
1053
1054         time(time_passes,
1055              "stability checking",
1056              || stability::check_unstable_api_usage(tcx));
1057
1058         // passes are timed inside typeck
1059         try_with_f!(typeck::check_crate(tcx), (tcx, analysis, incremental_hashes_map));
1060
1061         time(time_passes,
1062              "const checking",
1063              || consts::check_crate(tcx));
1064
1065         analysis.access_levels =
1066             time(time_passes, "privacy checking", || rustc_privacy::check_crate(tcx));
1067
1068         time(time_passes,
1069              "intrinsic checking",
1070              || middle::intrinsicck::check_crate(tcx));
1071
1072         time(time_passes,
1073              "effect checking",
1074              || middle::effect::check_crate(tcx));
1075
1076         time(time_passes,
1077              "match checking",
1078              || check_match::check_crate(tcx));
1079
1080         // this must run before MIR dump, because
1081         // "not all control paths return a value" is reported here.
1082         //
1083         // maybe move the check to a MIR pass?
1084         time(time_passes,
1085              "liveness checking",
1086              || middle::liveness::check_crate(tcx));
1087
1088         time(time_passes,
1089              "borrow checking",
1090              || borrowck::check_crate(tcx));
1091
1092         time(time_passes,
1093              "MIR borrow checking",
1094              || for def_id in tcx.body_owners() { tcx.mir_borrowck(def_id) });
1095
1096         // Avoid overwhelming user with errors if type checking failed.
1097         // I'm not sure how helpful this is, to be honest, but it avoids
1098         // a
1099         // lot of annoying errors in the compile-fail tests (basically,
1100         // lint warnings and so on -- kindck used to do this abort, but
1101         // kindck is gone now). -nmatsakis
1102         if sess.err_count() > 0 {
1103             return Ok(f(tcx, analysis, incremental_hashes_map, sess.compile_status()));
1104         }
1105
1106         analysis.reachable =
1107             time(time_passes,
1108                  "reachability checking",
1109                  || reachable::find_reachable(tcx));
1110
1111         time(time_passes, "death checking", || middle::dead::check_crate(tcx));
1112
1113         time(time_passes, "unused lib feature checking", || {
1114             stability::check_unused_or_stable_features(tcx)
1115         });
1116
1117         time(time_passes, "lint checking", || lint::check_crate(tcx));
1118
1119         return Ok(f(tcx, analysis, incremental_hashes_map, tcx.sess.compile_status()));
1120     })
1121 }
1122
1123 /// Run the translation phase to LLVM, after which the AST and analysis can
1124 /// be discarded.
1125 pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1126                                            analysis: ty::CrateAnalysis,
1127                                            incremental_hashes_map: IncrementalHashesMap,
1128                                            output_filenames: &OutputFilenames)
1129                                            -> write::OngoingCrateTranslation {
1130     let time_passes = tcx.sess.time_passes();
1131
1132     time(time_passes,
1133          "resolving dependency formats",
1134          || ::rustc::middle::dependency_format::calculate(tcx));
1135
1136     let translation =
1137         time(time_passes,
1138              "translation",
1139              move || trans::trans_crate(tcx, analysis, incremental_hashes_map, output_filenames));
1140
1141     if tcx.sess.profile_queries() {
1142         profile::dump("profile_queries".to_string())
1143     }
1144
1145     translation
1146 }
1147
1148 /// Run LLVM itself, producing a bitcode file, assembly file or object file
1149 /// as a side effect.
1150 #[cfg(feature="llvm")]
1151 pub fn phase_5_run_llvm_passes(sess: &Session,
1152                                dep_graph: &DepGraph,
1153                                trans: write::OngoingCrateTranslation)
1154                                -> (CompileResult, trans::CrateTranslation) {
1155     let trans = trans.join(sess, dep_graph);
1156
1157     if sess.opts.debugging_opts.incremental_info {
1158         write::dump_incremental_data(&trans);
1159     }
1160
1161     time(sess.time_passes(),
1162          "serialize work products",
1163          move || rustc_incremental::save_work_products(sess, dep_graph));
1164
1165     (sess.compile_status(), trans)
1166 }
1167
1168 /// Run the linker on any artifacts that resulted from the LLVM run.
1169 /// This should produce either a finished executable or library.
1170 #[cfg(feature="llvm")]
1171 pub fn phase_6_link_output(sess: &Session,
1172                            trans: &trans::CrateTranslation,
1173                            outputs: &OutputFilenames) {
1174     time(sess.time_passes(), "linking", || {
1175         ::rustc_trans::back::link::link_binary(sess,
1176                                                trans,
1177                                                outputs,
1178                                                &trans.crate_name.as_str())
1179     });
1180 }
1181
1182 fn escape_dep_filename(filename: &str) -> String {
1183     // Apparently clang and gcc *only* escape spaces:
1184     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
1185     filename.replace(" ", "\\ ")
1186 }
1187
1188 fn write_out_deps(sess: &Session, outputs: &OutputFilenames, crate_name: &str) {
1189     let mut out_filenames = Vec::new();
1190     for output_type in sess.opts.output_types.keys() {
1191         let file = outputs.path(*output_type);
1192         match *output_type {
1193             OutputType::Exe => {
1194                 for output in sess.crate_types.borrow().iter() {
1195                     let p = ::rustc_trans_utils::link::filename_for_input(
1196                         sess,
1197                         *output,
1198                         crate_name,
1199                         outputs
1200                     );
1201                     out_filenames.push(p);
1202                 }
1203             }
1204             _ => {
1205                 out_filenames.push(file);
1206             }
1207         }
1208     }
1209
1210     // Write out dependency rules to the dep-info file if requested
1211     if !sess.opts.output_types.contains_key(&OutputType::DepInfo) {
1212         return;
1213     }
1214     let deps_filename = outputs.path(OutputType::DepInfo);
1215
1216     let result =
1217         (|| -> io::Result<()> {
1218             // Build a list of files used to compile the output and
1219             // write Makefile-compatible dependency rules
1220             let files: Vec<String> = sess.codemap()
1221                                          .files()
1222                                          .iter()
1223                                          .filter(|fmap| fmap.is_real_file())
1224                                          .filter(|fmap| !fmap.is_imported())
1225                                          .map(|fmap| escape_dep_filename(&fmap.name))
1226                                          .collect();
1227             let mut file = fs::File::create(&deps_filename)?;
1228             for path in &out_filenames {
1229                 write!(file, "{}: {}\n\n", path.display(), files.join(" "))?;
1230             }
1231
1232             // Emit a fake target for each input file to the compilation. This
1233             // prevents `make` from spitting out an error if a file is later
1234             // deleted. For more info see #28735
1235             for path in files {
1236                 writeln!(file, "{}:", path)?;
1237             }
1238             Ok(())
1239         })();
1240
1241     match result {
1242         Ok(()) => {}
1243         Err(e) => {
1244             sess.fatal(&format!("error writing dependencies to `{}`: {}",
1245                                 deps_filename.display(),
1246                                 e));
1247         }
1248     }
1249 }
1250
1251 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
1252     // Unconditionally collect crate types from attributes to make them used
1253     let attr_types: Vec<config::CrateType> =
1254         attrs.iter()
1255              .filter_map(|a| {
1256                  if a.check_name("crate_type") {
1257                      match a.value_str() {
1258                          Some(ref n) if *n == "rlib" => {
1259                              Some(config::CrateTypeRlib)
1260                          }
1261                          Some(ref n) if *n == "dylib" => {
1262                              Some(config::CrateTypeDylib)
1263                          }
1264                          Some(ref n) if *n == "cdylib" => {
1265                              Some(config::CrateTypeCdylib)
1266                          }
1267                          Some(ref n) if *n == "lib" => {
1268                              Some(config::default_lib_output())
1269                          }
1270                          Some(ref n) if *n == "staticlib" => {
1271                              Some(config::CrateTypeStaticlib)
1272                          }
1273                          Some(ref n) if *n == "proc-macro" => {
1274                              Some(config::CrateTypeProcMacro)
1275                          }
1276                          Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
1277                          Some(_) => {
1278                              session.buffer_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
1279                                                  ast::CRATE_NODE_ID,
1280                                                  a.span,
1281                                                  "invalid `crate_type` value");
1282                              None
1283                          }
1284                          _ => {
1285                              session.struct_span_err(a.span, "`crate_type` requires a value")
1286                                  .note("for example: `#![crate_type=\"lib\"]`")
1287                                  .emit();
1288                              None
1289                          }
1290                      }
1291                  } else {
1292                      None
1293                  }
1294              })
1295              .collect();
1296
1297     // If we're generating a test executable, then ignore all other output
1298     // styles at all other locations
1299     if session.opts.test {
1300         return vec![config::CrateTypeExecutable];
1301     }
1302
1303     // Only check command line flags if present. If no types are specified by
1304     // command line, then reuse the empty `base` Vec to hold the types that
1305     // will be found in crate attributes.
1306     let mut base = session.opts.crate_types.clone();
1307     if base.is_empty() {
1308         base.extend(attr_types);
1309         if base.is_empty() {
1310             base.push(::rustc_trans_utils::link::default_output_for_target(session));
1311         }
1312         base.sort();
1313         base.dedup();
1314     }
1315
1316     base.into_iter()
1317         .filter(|crate_type| {
1318             let res = !::rustc_trans_utils::link::invalid_output_for_target(session, *crate_type);
1319
1320             if !res {
1321                 session.warn(&format!("dropping unsupported crate type `{}` for target `{}`",
1322                                       *crate_type,
1323                                       session.opts.target_triple));
1324             }
1325
1326             res
1327         })
1328         .collect()
1329 }
1330
1331 pub fn compute_crate_disambiguator(session: &Session) -> String {
1332     use std::hash::Hasher;
1333
1334     // The crate_disambiguator is a 128 bit hash. The disambiguator is fed
1335     // into various other hashes quite a bit (symbol hashes, incr. comp. hashes,
1336     // debuginfo type IDs, etc), so we don't want it to be too wide. 128 bits
1337     // should still be safe enough to avoid collisions in practice.
1338     // FIXME(mw): It seems that the crate_disambiguator is used everywhere as
1339     //            a hex-string instead of raw bytes. We should really use the
1340     //            smaller representation.
1341     let mut hasher = StableHasher::<Fingerprint>::new();
1342
1343     let mut metadata = session.opts.cg.metadata.clone();
1344     // We don't want the crate_disambiguator to dependent on the order
1345     // -C metadata arguments, so sort them:
1346     metadata.sort();
1347     // Every distinct -C metadata value is only incorporated once:
1348     metadata.dedup();
1349
1350     hasher.write(b"metadata");
1351     for s in &metadata {
1352         // Also incorporate the length of a metadata string, so that we generate
1353         // different values for `-Cmetadata=ab -Cmetadata=c` and
1354         // `-Cmetadata=a -Cmetadata=bc`
1355         hasher.write_usize(s.len());
1356         hasher.write(s.as_bytes());
1357     }
1358
1359     // If this is an executable, add a special suffix, so that we don't get
1360     // symbol conflicts when linking against a library of the same name.
1361     let is_exe = session.crate_types.borrow().contains(&config::CrateTypeExecutable);
1362
1363     format!("{}{}", hasher.finish().to_hex(), if is_exe { "-exe" } else {""})
1364 }
1365
1366 pub fn build_output_filenames(input: &Input,
1367                               odir: &Option<PathBuf>,
1368                               ofile: &Option<PathBuf>,
1369                               attrs: &[ast::Attribute],
1370                               sess: &Session)
1371                               -> OutputFilenames {
1372     match *ofile {
1373         None => {
1374             // "-" as input file will cause the parser to read from stdin so we
1375             // have to make up a name
1376             // We want to toss everything after the final '.'
1377             let dirpath = match *odir {
1378                 Some(ref d) => d.clone(),
1379                 None => PathBuf::new(),
1380             };
1381
1382             // If a crate name is present, we use it as the link name
1383             let stem = sess.opts
1384                            .crate_name
1385                            .clone()
1386                            .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
1387                            .unwrap_or(input.filestem());
1388
1389             OutputFilenames {
1390                 out_directory: dirpath,
1391                 out_filestem: stem,
1392                 single_output_file: None,
1393                 extra: sess.opts.cg.extra_filename.clone(),
1394                 outputs: sess.opts.output_types.clone(),
1395             }
1396         }
1397
1398         Some(ref out_file) => {
1399             let unnamed_output_types = sess.opts
1400                                            .output_types
1401                                            .values()
1402                                            .filter(|a| a.is_none())
1403                                            .count();
1404             let ofile = if unnamed_output_types > 1 {
1405                 sess.warn("due to multiple output types requested, the explicitly specified \
1406                            output file name will be adapted for each output type");
1407                 None
1408             } else {
1409                 Some(out_file.clone())
1410             };
1411             if *odir != None {
1412                 sess.warn("ignoring --out-dir flag due to -o flag.");
1413             }
1414
1415             let cur_dir = Path::new("");
1416
1417             OutputFilenames {
1418                 out_directory: out_file.parent().unwrap_or(cur_dir).to_path_buf(),
1419                 out_filestem: out_file.file_stem()
1420                                       .unwrap_or(OsStr::new(""))
1421                                       .to_str()
1422                                       .unwrap()
1423                                       .to_string(),
1424                 single_output_file: ofile,
1425                 extra: sess.opts.cg.extra_filename.clone(),
1426                 outputs: sess.opts.output_types.clone(),
1427             }
1428         }
1429     }
1430 }