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