src/librustc_driver/driver.rs

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