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::ty::{self, TyCtxt, Resolutions, GlobalArenas};
  24 use rustc::util::common::time;
  25 use rustc::util::nodemap::NodeSet;
  26 use rustc::util::fs::rename_or_copy_remove;
  27 use rustc_borrowck as borrowck;
  28 use rustc_incremental::{self, IncrementalHashesMap};
  29 use rustc_resolve::{MakeGlobMap, Resolver};
  30 use rustc_metadata::creader::CrateLoader;
  31 use rustc_metadata::cstore::{self, CStore};
  32 use rustc_trans::back::{link, write};
  33 use rustc_trans as trans;
  34 use rustc_typeck as typeck;
  35 use rustc_privacy;
  36 use rustc_plugin::registry::Registry;
  37 use rustc_plugin as plugin;
  38 use rustc_passes::{ast_validation, no_asm, loops, consts, rvalues,
  39                    static_recursion, hir_stats, mir_stats};
  40 use rustc_const_eval::check_match;
  41 use super::Compilation;
  42
  43 use serialize::json;
  44
  45 use std::env;
  46 use std::ffi::{OsString, OsStr};
  47 use std::fs;
  48 use std::io::{self, Write};
  49 use std::iter;
  50 use std::path::{Path, PathBuf};
  51 use std::rc::Rc;
  52 use syntax::{ast, diagnostics, visit};
  53 use syntax::attr;
  54 use syntax::ext::base::ExtCtxt;
  55 use syntax::parse::{self, PResult};
  56 use syntax::symbol::Symbol;
  57 use syntax::util::node_count::NodeCounter;
  58 use syntax;
  59 use syntax_ext;
  60 use arena::DroplessArena;
  61
  62 use derive_registrar;
  63
  64 pub fn compile_input(sess: &Session,
  65                      cstore: &CStore,
  66                      input: &Input,
  67                      outdir: &Option<PathBuf>,
  68                      output: &Option<PathBuf>,
  69                      addl_plugins: Option<Vec<String>>,
  70                      control: &CompileController) -> CompileResult {
  71     macro_rules! controller_entry_point {
  72         ($point: ident, $tsess: expr, $make_state: expr, $phase_result: expr) => {{
  73             let state = &mut $make_state;
  74             let phase_result: &CompileResult = &$phase_result;
  75             if phase_result.is_ok() || control.$point.run_callback_on_error {
  76                 (control.$point.callback)(state);
  77             }
  78
  79             if control.$point.stop == Compilation::Stop {
  80                 return compile_result_from_err_count($tsess.err_count());
  81             }
  82         }}
  83     }
  84
  85     // We need nested scopes here, because the intermediate results can keep
  86     // large chunks of memory alive and we want to free them as soon as
  87     // possible to keep the peak memory usage low
  88     let (outputs, trans) = {
  89         let krate = match phase_1_parse_input(sess, input) {
  90             Ok(krate) => krate,
  91             Err(mut parse_error) => {
  92                 parse_error.emit();
  93                 return Err(1);
  94             }
  95         };
  96
  97         let (krate, registry) = {
  98             let mut compile_state = CompileState::state_after_parse(input,
  99                                                                     sess,
 100                                                                     outdir,
 101                                                                     output,
 102                                                                     krate,
 103                                                                     &cstore);
 104             controller_entry_point!(after_parse,
 105                                     sess,
 106                                     compile_state,
 107                                     Ok(()));
 108
 109             (compile_state.krate.unwrap(), compile_state.registry)
 110         };
 111
 112         let outputs = build_output_filenames(input, outdir, output, &krate.attrs, sess);
 113         let crate_name = link::find_crate_name(Some(sess), &krate.attrs, input);
 114         let ExpansionResult { expanded_crate, defs, analysis, resolutions, mut hir_forest } = {
 115             phase_2_configure_and_expand(
 116                 sess, &cstore, krate, registry, &crate_name, addl_plugins, control.make_glob_map,
 117                 |expanded_crate| {
 118                     let mut state = CompileState::state_after_expand(
 119                         input, sess, outdir, output, &cstore, expanded_crate, &crate_name,
 120                     );
 121                     controller_entry_point!(after_expand, sess, state, Ok(()));
 122                     Ok(())
 123                 }
 124             )?
 125         };
 126
 127         write_out_deps(sess, &outputs, &crate_name);
 128         if sess.opts.output_types.contains_key(&OutputType::DepInfo) &&
 129             sess.opts.output_types.keys().count() == 1 {
 130             return Ok(())
 131         }
 132
 133         let arena = DroplessArena::new();
 134         let arenas = GlobalArenas::new();
 135
 136         // Construct the HIR map
 137         let hir_map = time(sess.time_passes(),
 138                            "indexing hir",
 139                            || hir_map::map_crate(&mut hir_forest, defs));
 140
 141         {
 142             let _ignore = hir_map.dep_graph.in_ignore();
 143             controller_entry_point!(after_hir_lowering,
 144                                     sess,
 145                                     CompileState::state_after_hir_lowering(input,
 146                                                                   sess,
 147                                                                   outdir,
 148                                                                   output,
 149                                                                   &arena,
 150                                                                   &arenas,
 151                                                                   &cstore,
 152                                                                   &hir_map,
 153                                                                   &analysis,
 154                                                                   &resolutions,
 155                                                                   &expanded_crate,
 156                                                                   &hir_map.krate(),
 157                                                                   &crate_name),
 158                                     Ok(()));
 159         }
 160
 161         time(sess.time_passes(), "attribute checking", || {
 162             hir::check_attr::check_crate(sess, &expanded_crate);
 163         });
 164
 165         let opt_crate = if keep_ast(sess) {
 166             Some(&expanded_crate)
 167         } else {
 168             drop(expanded_crate);
 169             None
 170         };
 171
 172         phase_3_run_analysis_passes(sess,
 173                                     hir_map,
 174                                     analysis,
 175                                     resolutions,
 176                                     &arena,
 177                                     &arenas,
 178                                     &crate_name,
 179                                     |tcx, analysis, incremental_hashes_map, result| {
 180             {
 181                 // Eventually, we will want to track plugins.
 182                 let _ignore = tcx.dep_graph.in_ignore();
 183
 184                 let mut state = CompileState::state_after_analysis(input,
 185                                                                    sess,
 186                                                                    outdir,
 187                                                                    output,
 188                                                                    opt_crate,
 189                                                                    tcx.hir.krate(),
 190                                                                    &analysis,
 191                                                                    tcx,
 192                                                                    &crate_name);
 193                 (control.after_analysis.callback)(&mut state);
 194
 195                 if control.after_analysis.stop == Compilation::Stop {
 196                     return result.and_then(|_| Err(0usize));
 197                 }
 198             }
 199
 200             result?;
 201
 202             if log_enabled!(::log::LogLevel::Info) {
 203                 println!("Pre-trans");
 204                 tcx.print_debug_stats();
 205             }
 206             let trans = phase_4_translate_to_llvm(tcx, analysis, &incremental_hashes_map);
 207
 208             if log_enabled!(::log::LogLevel::Info) {
 209                 println!("Post-trans");
 210                 tcx.print_debug_stats();
 211             }
 212
 213             if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
 214                 if let Err(e) = mir::transform::dump_mir::emit_mir(tcx, &outputs) {
 215                     sess.err(&format!("could not emit MIR: {}", e));
 216                     sess.abort_if_errors();
 217                 }
 218             }
 219
 220             Ok((outputs, trans))
 221         })??
 222     };
 223
 224     if sess.opts.debugging_opts.print_type_sizes {
 225         sess.code_stats.borrow().print_type_sizes();
 226     }
 227
 228     let phase5_result = phase_5_run_llvm_passes(sess, &trans, &outputs);
 229
 230     controller_entry_point!(after_llvm,
 231                             sess,
 232                             CompileState::state_after_llvm(input, sess, outdir, output, &trans),
 233                             phase5_result);
 234     phase5_result?;
 235
 236     write::cleanup_llvm(&trans);
 237
 238     phase_6_link_output(sess, &trans, &outputs);
 239
 240     // Now that we won't touch anything in the incremental compilation directory
 241     // any more, we can finalize it (which involves renaming it)
 242     rustc_incremental::finalize_session_directory(sess, trans.link.crate_hash);
 243
 244     if sess.opts.debugging_opts.perf_stats {
 245         sess.print_perf_stats();
 246     }
 247
 248     controller_entry_point!(compilation_done,
 249                             sess,
 250                             CompileState::state_when_compilation_done(input, sess, outdir, output),
 251                             Ok(()));
 252
 253     Ok(())
 254 }
 255
 256 fn keep_hygiene_data(sess: &Session) -> bool {
 257     sess.opts.debugging_opts.keep_hygiene_data
 258 }
 259
 260 fn keep_ast(sess: &Session) -> bool {
 261     sess.opts.debugging_opts.keep_ast || ::save_analysis(sess)
 262 }
 263
 264 /// The name used for source code that doesn't originate in a file
 265 /// (e.g. source from stdin or a string)
 266 pub fn anon_src() -> String {
 267     "<anon>".to_string()
 268 }
 269
 270 pub fn source_name(input: &Input) -> String {
 271     match *input {
 272         // FIXME (#9639): This needs to handle non-utf8 paths
 273         Input::File(ref ifile) => ifile.to_str().unwrap().to_string(),
 274         Input::Str { ref name, .. } => name.clone(),
 275     }
 276 }
 277
 278 /// CompileController is used to customise compilation, it allows compilation to
 279 /// be stopped and/or to call arbitrary code at various points in compilation.
 280 /// It also allows for various flags to be set to influence what information gets
 281 /// collected during compilation.
 282 ///
 283 /// This is a somewhat higher level controller than a Session - the Session
 284 /// controls what happens in each phase, whereas the CompileController controls
 285 /// whether a phase is run at all and whether other code (from outside the
 286 /// the compiler) is run between phases.
 287 ///
 288 /// Note that if compilation is set to stop and a callback is provided for a
 289 /// given entry point, the callback is called before compilation is stopped.
 290 ///
 291 /// Expect more entry points to be added in the future.
 292 pub struct CompileController<'a> {
 293     pub after_parse: PhaseController<'a>,
 294     pub after_expand: PhaseController<'a>,
 295     pub after_hir_lowering: PhaseController<'a>,
 296     pub after_analysis: PhaseController<'a>,
 297     pub after_llvm: PhaseController<'a>,
 298     pub compilation_done: PhaseController<'a>,
 299
 300     pub make_glob_map: MakeGlobMap,
 301 }
 302
 303 impl<'a> CompileController<'a> {
 304     pub fn basic() -> CompileController<'a> {
 305         CompileController {
 306             after_parse: PhaseController::basic(),
 307             after_expand: PhaseController::basic(),
 308             after_hir_lowering: PhaseController::basic(),
 309             after_analysis: PhaseController::basic(),
 310             after_llvm: PhaseController::basic(),
 311             compilation_done: PhaseController::basic(),
 312             make_glob_map: MakeGlobMap::No,
 313         }
 314     }
 315 }
 316
 317 pub struct PhaseController<'a> {
 318     pub stop: Compilation,
 319     // If true then the compiler will try to run the callback even if the phase
 320     // ends with an error. Note that this is not always possible.
 321     pub run_callback_on_error: bool,
 322     pub callback: Box<Fn(&mut CompileState) + 'a>,
 323 }
 324
 325 impl<'a> PhaseController<'a> {
 326     pub fn basic() -> PhaseController<'a> {
 327         PhaseController {
 328             stop: Compilation::Continue,
 329             run_callback_on_error: false,
 330             callback: box |_| {},
 331         }
 332     }
 333 }
 334
 335 /// State that is passed to a callback. What state is available depends on when
 336 /// during compilation the callback is made. See the various constructor methods
 337 /// (`state_*`) in the impl to see which data is provided for any given entry point.
 338 pub struct CompileState<'a, 'tcx: 'a> {
 339     pub input: &'a Input,
 340     pub session: &'tcx Session,
 341     pub krate: Option<ast::Crate>,
 342     pub registry: Option<Registry<'a>>,
 343     pub cstore: Option<&'a CStore>,
 344     pub crate_name: Option<&'a str>,
 345     pub output_filenames: Option<&'a OutputFilenames>,
 346     pub out_dir: Option<&'a Path>,
 347     pub out_file: Option<&'a Path>,
 348     pub arena: Option<&'tcx DroplessArena>,
 349     pub arenas: Option<&'tcx GlobalArenas<'tcx>>,
 350     pub expanded_crate: Option<&'a ast::Crate>,
 351     pub hir_crate: Option<&'a hir::Crate>,
 352     pub hir_map: Option<&'a hir_map::Map<'tcx>>,
 353     pub resolutions: Option<&'a Resolutions>,
 354     pub analysis: Option<&'a ty::CrateAnalysis>,
 355     pub tcx: Option<TyCtxt<'a, 'tcx, 'tcx>>,
 356     pub trans: Option<&'a trans::CrateTranslation>,
 357 }
 358
 359 impl<'a, 'tcx> CompileState<'a, 'tcx> {
 360     fn empty(input: &'a Input,
 361              session: &'tcx Session,
 362              out_dir: &'a Option<PathBuf>)
 363              -> Self {
 364         CompileState {
 365             input: input,
 366             session: session,
 367             out_dir: out_dir.as_ref().map(|s| &**s),
 368             out_file: None,
 369             arena: None,
 370             arenas: None,
 371             krate: None,
 372             registry: None,
 373             cstore: None,
 374             crate_name: None,
 375             output_filenames: None,
 376             expanded_crate: None,
 377             hir_crate: None,
 378             hir_map: None,
 379             resolutions: None,
 380             analysis: None,
 381             tcx: None,
 382             trans: None,
 383         }
 384     }
 385
 386     fn state_after_parse(input: &'a Input,
 387                          session: &'tcx Session,
 388                          out_dir: &'a Option<PathBuf>,
 389                          out_file: &'a Option<PathBuf>,
 390                          krate: ast::Crate,
 391                          cstore: &'a CStore)
 392                          -> Self {
 393         CompileState {
 394             // Initialize the registry before moving `krate`
 395             registry: Some(Registry::new(&session, krate.span)),
 396             krate: Some(krate),
 397             cstore: Some(cstore),
 398             out_file: out_file.as_ref().map(|s| &**s),
 399             ..CompileState::empty(input, session, out_dir)
 400         }
 401     }
 402
 403     fn state_after_expand(input: &'a Input,
 404                           session: &'tcx Session,
 405                           out_dir: &'a Option<PathBuf>,
 406                           out_file: &'a Option<PathBuf>,
 407                           cstore: &'a CStore,
 408                           expanded_crate: &'a ast::Crate,
 409                           crate_name: &'a str)
 410                           -> Self {
 411         CompileState {
 412             crate_name: Some(crate_name),
 413             cstore: Some(cstore),
 414             expanded_crate: Some(expanded_crate),
 415             out_file: out_file.as_ref().map(|s| &**s),
 416             ..CompileState::empty(input, session, out_dir)
 417         }
 418     }
 419
 420     fn state_after_hir_lowering(input: &'a Input,
 421                                 session: &'tcx Session,
 422                                 out_dir: &'a Option<PathBuf>,
 423                                 out_file: &'a Option<PathBuf>,
 424                                 arena: &'tcx DroplessArena,
 425                                 arenas: &'tcx GlobalArenas<'tcx>,
 426                                 cstore: &'a CStore,
 427                                 hir_map: &'a hir_map::Map<'tcx>,
 428                                 analysis: &'a ty::CrateAnalysis,
 429                                 resolutions: &'a Resolutions,
 430                                 krate: &'a ast::Crate,
 431                                 hir_crate: &'a hir::Crate,
 432                                 crate_name: &'a str)
 433                                 -> Self {
 434         CompileState {
 435             crate_name: Some(crate_name),
 436             arena: Some(arena),
 437             arenas: Some(arenas),
 438             cstore: Some(cstore),
 439             hir_map: Some(hir_map),
 440             analysis: Some(analysis),
 441             resolutions: Some(resolutions),
 442             expanded_crate: Some(krate),
 443             hir_crate: Some(hir_crate),
 444             out_file: out_file.as_ref().map(|s| &**s),
 445             ..CompileState::empty(input, session, out_dir)
 446         }
 447     }
 448
 449     fn state_after_analysis(input: &'a Input,
 450                             session: &'tcx Session,
 451                             out_dir: &'a Option<PathBuf>,
 452                             out_file: &'a Option<PathBuf>,
 453                             krate: Option<&'a ast::Crate>,
 454                             hir_crate: &'a hir::Crate,
 455                             analysis: &'a ty::CrateAnalysis,
 456                             tcx: TyCtxt<'a, 'tcx, 'tcx>,
 457                             crate_name: &'a str)
 458                             -> Self {
 459         CompileState {
 460             analysis: Some(analysis),
 461             tcx: Some(tcx),
 462             expanded_crate: krate,
 463             hir_crate: Some(hir_crate),
 464             crate_name: Some(crate_name),
 465             out_file: out_file.as_ref().map(|s| &**s),
 466             ..CompileState::empty(input, session, out_dir)
 467         }
 468     }
 469
 470
 471     fn state_after_llvm(input: &'a Input,
 472                         session: &'tcx Session,
 473                         out_dir: &'a Option<PathBuf>,
 474                         out_file: &'a Option<PathBuf>,
 475                         trans: &'a trans::CrateTranslation)
 476                         -> Self {
 477         CompileState {
 478             trans: Some(trans),
 479             out_file: out_file.as_ref().map(|s| &**s),
 480             ..CompileState::empty(input, session, out_dir)
 481         }
 482     }
 483
 484     fn state_when_compilation_done(input: &'a Input,
 485                                     session: &'tcx Session,
 486                                     out_dir: &'a Option<PathBuf>,
 487                                     out_file: &'a Option<PathBuf>)
 488                                     -> Self {
 489         CompileState {
 490             out_file: out_file.as_ref().map(|s| &**s),
 491             ..CompileState::empty(input, session, out_dir)
 492         }
 493     }
 494 }
 495
 496 pub fn phase_1_parse_input<'a>(sess: &'a Session, input: &Input) -> PResult<'a, ast::Crate> {
 497     let continue_after_error = sess.opts.debugging_opts.continue_parse_after_error;
 498     sess.diagnostic().set_continue_after_error(continue_after_error);
 499
 500     let krate = time(sess.time_passes(), "parsing", || {
 501         match *input {
 502             Input::File(ref file) => {
 503                 parse::parse_crate_from_file(file, &sess.parse_sess)
 504             }
 505             Input::Str { ref input, ref name } => {
 506                 parse::parse_crate_from_source_str(name.clone(), input.clone(), &sess.parse_sess)
 507             }
 508         }
 509     })?;
 510
 511     sess.diagnostic().set_continue_after_error(true);
 512
 513     if sess.opts.debugging_opts.ast_json_noexpand {
 514         println!("{}", json::as_json(&krate));
 515     }
 516
 517     if sess.opts.debugging_opts.input_stats {
 518         println!("Lines of code:             {}", sess.codemap().count_lines());
 519         println!("Pre-expansion node count:  {}", count_nodes(&krate));
 520     }
 521
 522     if let Some(ref s) = sess.opts.debugging_opts.show_span {
 523         syntax::show_span::run(sess.diagnostic(), s, &krate);
 524     }
 525
 526     if sess.opts.debugging_opts.hir_stats {
 527         hir_stats::print_ast_stats(&krate, "PRE EXPANSION AST STATS");
 528     }
 529
 530     Ok(krate)
 531 }
 532
 533 fn count_nodes(krate: &ast::Crate) -> usize {
 534     let mut counter = NodeCounter::new();
 535     visit::walk_crate(&mut counter, krate);
 536     counter.count
 537 }
 538
 539 // For continuing compilation after a parsed crate has been
 540 // modified
 541
 542 pub struct ExpansionResult {
 543     pub expanded_crate: ast::Crate,
 544     pub defs: hir_map::Definitions,
 545     pub analysis: ty::CrateAnalysis,
 546     pub resolutions: Resolutions,
 547     pub hir_forest: hir_map::Forest,
 548 }
 549
 550 /// Run the "early phases" of the compiler: initial `cfg` processing,
 551 /// loading compiler plugins (including those from `addl_plugins`),
 552 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 553 /// harness if one is to be provided, injection of a dependency on the
 554 /// standard library and prelude, and name resolution.
 555 ///
 556 /// Returns `None` if we're aborting after handling -W help.
 557 pub fn phase_2_configure_and_expand<F>(sess: &Session,
 558                                        cstore: &CStore,
 559                                        krate: ast::Crate,
 560                                        registry: Option<Registry>,
 561                                        crate_name: &str,
 562                                        addl_plugins: Option<Vec<String>>,
 563                                        make_glob_map: MakeGlobMap,
 564                                        after_expand: F)
 565                                        -> Result<ExpansionResult, usize>
 566     where F: FnOnce(&ast::Crate) -> CompileResult,
 567 {
 568     let time_passes = sess.time_passes();
 569
 570     let (mut krate, features) = syntax::config::features(krate, &sess.parse_sess, sess.opts.test);
 571     // these need to be set "early" so that expansion sees `quote` if enabled.
 572     *sess.features.borrow_mut() = features;
 573
 574     *sess.crate_types.borrow_mut() = collect_crate_types(sess, &krate.attrs);
 575     *sess.crate_disambiguator.borrow_mut() = Symbol::intern(&compute_crate_disambiguator(sess));
 576
 577     time(time_passes, "recursion limit", || {
 578         middle::recursion_limit::update_limits(sess, &krate);
 579     });
 580
 581     krate = time(time_passes, "crate injection", || {
 582         let alt_std_name = sess.opts.alt_std_name.clone();
 583         syntax::std_inject::maybe_inject_crates_ref(krate, alt_std_name)
 584     });
 585
 586     let mut addl_plugins = Some(addl_plugins);
 587     let registrars = time(time_passes, "plugin loading", || {
 588         plugin::load::load_plugins(sess,
 589                                    &cstore,
 590                                    &krate,
 591                                    crate_name,
 592                                    addl_plugins.take().unwrap())
 593     });
 594
 595     let mut registry = registry.unwrap_or(Registry::new(sess, krate.span));
 596
 597     time(time_passes, "plugin registration", || {
 598         if sess.features.borrow().rustc_diagnostic_macros {
 599             registry.register_macro("__diagnostic_used",
 600                                     diagnostics::plugin::expand_diagnostic_used);
 601             registry.register_macro("__register_diagnostic",
 602                                     diagnostics::plugin::expand_register_diagnostic);
 603             registry.register_macro("__build_diagnostic_array",
 604                                     diagnostics::plugin::expand_build_diagnostic_array);
 605         }
 606
 607         for registrar in registrars {
 608             registry.args_hidden = Some(registrar.args);
 609             (registrar.fun)(&mut registry);
 610         }
 611     });
 612
 613     let whitelisted_legacy_custom_derives = registry.take_whitelisted_custom_derives();
 614     let Registry { syntax_exts, early_lint_passes, late_lint_passes, lint_groups,
 615                    llvm_passes, attributes, .. } = registry;
 616
 617     sess.track_errors(|| {
 618         let mut ls = sess.lint_store.borrow_mut();
 619         for pass in early_lint_passes {
 620             ls.register_early_pass(Some(sess), true, pass);
 621         }
 622         for pass in late_lint_passes {
 623             ls.register_late_pass(Some(sess), true, pass);
 624         }
 625
 626         for (name, to) in lint_groups {
 627             ls.register_group(Some(sess), true, name, to);
 628         }
 629
 630         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
 631         *sess.plugin_attributes.borrow_mut() = attributes.clone();
 632     })?;
 633
 634     // Lint plugins are registered; now we can process command line flags.
 635     if sess.opts.describe_lints {
 636         super::describe_lints(&sess.lint_store.borrow(), true);
 637         return Err(0);
 638     }
 639     sess.track_errors(|| sess.lint_store.borrow_mut().process_command_line(sess))?;
 640
 641     // Currently, we ignore the name resolution data structures for the purposes of dependency
 642     // tracking. Instead we will run name resolution and include its output in the hash of each
 643     // item, much like we do for macro expansion. In other words, the hash reflects not just
 644     // its contents but the results of name resolution on those contents. Hopefully we'll push
 645     // this back at some point.
 646     let _ignore = sess.dep_graph.in_ignore();
 647     let mut crate_loader = CrateLoader::new(sess, &cstore, crate_name);
 648     crate_loader.preprocess(&krate);
 649     let resolver_arenas = Resolver::arenas();
 650     let mut resolver = Resolver::new(sess,
 651                                      &krate,
 652                                      crate_name,
 653                                      make_glob_map,
 654                                      &mut crate_loader,
 655                                      &resolver_arenas);
 656     resolver.whitelisted_legacy_custom_derives = whitelisted_legacy_custom_derives;
 657     syntax_ext::register_builtins(&mut resolver, syntax_exts, sess.features.borrow().quote);
 658
 659     krate = time(time_passes, "expansion", || {
 660         // Windows dlls do not have rpaths, so they don't know how to find their
 661         // dependencies. It's up to us to tell the system where to find all the
 662         // dependent dlls. Note that this uses cfg!(windows) as opposed to
 663         // targ_cfg because syntax extensions are always loaded for the host
 664         // compiler, not for the target.
 665         //
 666         // This is somewhat of an inherently racy operation, however, as
 667         // multiple threads calling this function could possibly continue
 668         // extending PATH far beyond what it should. To solve this for now we
 669         // just don't add any new elements to PATH which are already there
 670         // within PATH. This is basically a targeted fix at #17360 for rustdoc
 671         // which runs rustc in parallel but has been seen (#33844) to cause
 672         // problems with PATH becoming too long.
 673         let mut old_path = OsString::new();
 674         if cfg!(windows) {
 675             old_path = env::var_os("PATH").unwrap_or(old_path);
 676             let mut new_path = sess.host_filesearch(PathKind::All)
 677                                    .get_dylib_search_paths();
 678             for path in env::split_paths(&old_path) {
 679                 if !new_path.contains(&path) {
 680                     new_path.push(path);
 681                 }
 682             }
 683             env::set_var("PATH",
 684                 &env::join_paths(new_path.iter()
 685                                          .filter(|p| env::join_paths(iter::once(p)).is_ok()))
 686                      .unwrap());
 687         }
 688         let features = sess.features.borrow();
 689         let cfg = syntax::ext::expand::ExpansionConfig {
 690             features: Some(&features),
 691             recursion_limit: sess.recursion_limit.get(),
 692             trace_mac: sess.opts.debugging_opts.trace_macros,
 693             should_test: sess.opts.test,
 694             ..syntax::ext::expand::ExpansionConfig::default(crate_name.to_string())
 695         };
 696
 697         let mut ecx = ExtCtxt::new(&sess.parse_sess, cfg, &mut resolver);
 698         let err_count = ecx.parse_sess.span_diagnostic.err_count();
 699
 700         let krate = ecx.monotonic_expander().expand_crate(krate);
 701
 702         let mut missing_fragment_specifiers: Vec<_> =
 703             ecx.parse_sess.missing_fragment_specifiers.borrow().iter().cloned().collect();
 704         missing_fragment_specifiers.sort();
 705         for span in missing_fragment_specifiers {
 706             let lint = lint::builtin::MISSING_FRAGMENT_SPECIFIER;
 707             let msg = "missing fragment specifier".to_string();
 708             sess.add_lint(lint, ast::CRATE_NODE_ID, span, msg);
 709         }
 710         if ecx.parse_sess.span_diagnostic.err_count() - ecx.resolve_err_count > err_count {
 711             ecx.parse_sess.span_diagnostic.abort_if_errors();
 712         }
 713         if cfg!(windows) {
 714             env::set_var("PATH", &old_path);
 715         }
 716         krate
 717     });
 718
 719     krate = time(time_passes, "maybe building test harness", || {
 720         syntax::test::modify_for_testing(&sess.parse_sess,
 721                                          &mut resolver,
 722                                          sess.opts.test,
 723                                          krate,
 724                                          sess.diagnostic())
 725     });
 726
 727     // If we're in rustdoc we're always compiling as an rlib, but that'll trip a
 728     // bunch of checks in the `modify` function below. For now just skip this
 729     // step entirely if we're rustdoc as it's not too useful anyway.
 730     if !sess.opts.actually_rustdoc {
 731         krate = time(time_passes, "maybe creating a macro crate", || {
 732             let crate_types = sess.crate_types.borrow();
 733             let num_crate_types = crate_types.len();
 734             let is_proc_macro_crate = crate_types.contains(&config::CrateTypeProcMacro);
 735             let is_test_crate = sess.opts.test;
 736             syntax_ext::proc_macro_registrar::modify(&sess.parse_sess,
 737                                                      &mut resolver,
 738                                                      krate,
 739                                                      is_proc_macro_crate,
 740                                                      is_test_crate,
 741                                                      num_crate_types,
 742                                                      sess.diagnostic())
 743         });
 744     }
 745
 746     after_expand(&krate)?;
 747
 748     if sess.opts.debugging_opts.input_stats {
 749         println!("Post-expansion node count: {}", count_nodes(&krate));
 750     }
 751
 752     if sess.opts.debugging_opts.hir_stats {
 753         hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS");
 754     }
 755
 756     if sess.opts.debugging_opts.ast_json {
 757         println!("{}", json::as_json(&krate));
 758     }
 759
 760     time(time_passes,
 761          "checking for inline asm in case the target doesn't support it",
 762          || no_asm::check_crate(sess, &krate));
 763
 764     time(time_passes,
 765          "early lint checks",
 766          || lint::check_ast_crate(sess, &krate));
 767
 768     time(time_passes,
 769          "AST validation",
 770          || ast_validation::check_crate(sess, &krate));
 771
 772     time(time_passes, "name resolution", || -> CompileResult {
 773         resolver.resolve_crate(&krate);
 774         Ok(())
 775     })?;
 776
 777     if resolver.found_unresolved_macro {
 778         sess.parse_sess.span_diagnostic.abort_if_errors();
 779     }
 780
 781     // Needs to go *after* expansion to be able to check the results of macro expansion.
 782     time(time_passes, "complete gated feature checking", || {
 783         sess.track_errors(|| {
 784             syntax::feature_gate::check_crate(&krate,
 785                                               &sess.parse_sess,
 786                                               &sess.features.borrow(),
 787                                               &attributes,
 788                                               sess.opts.unstable_features);
 789         })
 790     })?;
 791
 792     // Lower ast -> hir.
 793     let hir_forest = time(time_passes, "lowering ast -> hir", || {
 794         let hir_crate = lower_crate(sess, &krate, &mut resolver);
 795
 796         if sess.opts.debugging_opts.hir_stats {
 797             hir_stats::print_hir_stats(&hir_crate);
 798         }
 799
 800         hir_map::Forest::new(hir_crate, &sess.dep_graph)
 801     });
 802
 803     // Discard hygiene data, which isn't required after lowering to HIR.
 804     if !keep_hygiene_data(sess) {
 805         syntax::ext::hygiene::clear_markings();
 806     }
 807
 808     Ok(ExpansionResult {
 809         expanded_crate: krate,
 810         defs: resolver.definitions,
 811         analysis: ty::CrateAnalysis {
 812             access_levels: Rc::new(AccessLevels::default()),
 813             reachable: NodeSet(),
 814             name: crate_name.to_string(),
 815             glob_map: if resolver.make_glob_map { Some(resolver.glob_map) } else { None },
 816         },
 817         resolutions: Resolutions {
 818             freevars: resolver.freevars,
 819             export_map: resolver.export_map,
 820             trait_map: resolver.trait_map,
 821             maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
 822         },
 823         hir_forest: hir_forest,
 824     })
 825 }
 826
 827 /// Run the resolution, typechecking, region checking and other
 828 /// miscellaneous analysis passes on the crate. Return various
 829 /// structures carrying the results of the analysis.
 830 pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 831                                                hir_map: hir_map::Map<'tcx>,
 832                                                mut analysis: ty::CrateAnalysis,
 833                                                resolutions: Resolutions,
 834                                                arena: &'tcx DroplessArena,
 835                                                arenas: &'tcx GlobalArenas<'tcx>,
 836                                                name: &str,
 837                                                f: F)
 838                                                -> Result<R, usize>
 839     where F: for<'a> FnOnce(TyCtxt<'a, 'tcx, 'tcx>,
 840                             ty::CrateAnalysis,
 841                             IncrementalHashesMap,
 842                             CompileResult) -> R
 843 {
 844     macro_rules! try_with_f {
 845         ($e: expr, ($t: expr, $a: expr, $h: expr)) => {
 846             match $e {
 847                 Ok(x) => x,
 848                 Err(x) => {
 849                     f($t, $a, $h, Err(x));
 850                     return Err(x);
 851                 }
 852             }
 853         }
 854     }
 855
 856     let time_passes = sess.time_passes();
 857
 858     let lang_items = time(time_passes, "language item collection", || {
 859         sess.track_errors(|| {
 860             middle::lang_items::collect_language_items(&sess, &hir_map)
 861         })
 862     })?;
 863
 864     let named_region_map = time(time_passes,
 865                                 "lifetime resolution",
 866                                 || middle::resolve_lifetime::krate(sess, &hir_map))?;
 867
 868     time(time_passes,
 869          "looking for entry point",
 870          || middle::entry::find_entry_point(sess, &hir_map));
 871
 872     sess.plugin_registrar_fn.set(time(time_passes, "looking for plugin registrar", || {
 873         plugin::build::find_plugin_registrar(sess.diagnostic(), &hir_map)
 874     }));
 875     sess.derive_registrar_fn.set(derive_registrar::find(&hir_map));
 876
 877     let region_map = time(time_passes,
 878                           "region resolution",
 879                           || middle::region::resolve_crate(sess, &hir_map));
 880
 881     time(time_passes,
 882          "loop checking",
 883          || loops::check_crate(sess, &hir_map));
 884
 885     time(time_passes,
 886               "static item recursion checking",
 887               || static_recursion::check_crate(sess, &hir_map))?;
 888
 889     let index = stability::Index::new(&hir_map);
 890
 891     let mut local_providers = ty::maps::Providers::default();
 892     mir::provide(&mut local_providers);
 893     rustc_privacy::provide(&mut local_providers);
 894     typeck::provide(&mut local_providers);
 895     ty::provide(&mut local_providers);
 896     reachable::provide(&mut local_providers);
 897
 898     let mut extern_providers = ty::maps::Providers::default();
 899     cstore::provide(&mut extern_providers);
 900
 901     TyCtxt::create_and_enter(sess,
 902                              local_providers,
 903                              extern_providers,
 904                              arenas,
 905                              arena,
 906                              resolutions,
 907                              named_region_map,
 908                              hir_map,
 909                              region_map,
 910                              lang_items,
 911                              index,
 912                              name,
 913                              |tcx| {
 914         let incremental_hashes_map =
 915             time(time_passes,
 916                  "compute_incremental_hashes_map",
 917                  || rustc_incremental::compute_incremental_hashes_map(tcx));
 918         time(time_passes,
 919              "load_dep_graph",
 920              || rustc_incremental::load_dep_graph(tcx, &incremental_hashes_map));
 921
 922         time(time_passes, "stability index", || {
 923             tcx.stability.borrow_mut().build(tcx)
 924         });
 925
 926         time(time_passes,
 927              "stability checking",
 928              || stability::check_unstable_api_usage(tcx));
 929
 930         // passes are timed inside typeck
 931         try_with_f!(typeck::check_crate(tcx), (tcx, analysis, incremental_hashes_map));
 932
 933         time(time_passes,
 934              "const checking",
 935              || consts::check_crate(tcx));
 936
 937         analysis.access_levels =
 938             time(time_passes, "privacy checking", || rustc_privacy::check_crate(tcx));
 939
 940         time(time_passes,
 941              "intrinsic checking",
 942              || middle::intrinsicck::check_crate(tcx));
 943
 944         time(time_passes,
 945              "effect checking",
 946              || middle::effect::check_crate(tcx));
 947
 948         time(time_passes,
 949              "match checking",
 950              || check_match::check_crate(tcx));
 951
 952         // this must run before MIR dump, because
 953         // "not all control paths return a value" is reported here.
 954         //
 955         // maybe move the check to a MIR pass?
 956         time(time_passes,
 957              "liveness checking",
 958              || middle::liveness::check_crate(tcx));
 959
 960         time(time_passes,
 961              "rvalue checking",
 962              || rvalues::check_crate(tcx));
 963
 964         time(time_passes,
 965              "MIR dump",
 966              || mir::mir_map::build_mir_for_crate(tcx));
 967
 968         if sess.opts.debugging_opts.mir_stats {
 969             mir_stats::print_mir_stats(tcx, "PRE CLEANUP MIR STATS");
 970         }
 971
 972         time(time_passes, "MIR cleanup and validation", || {
 973             let mut passes = sess.mir_passes.borrow_mut();
 974             // Push all the built-in validation passes.
 975             // NB: if you’re adding an *optimisation* it ought to go to another set of passes
 976             // in stage 4 below.
 977             passes.push_hook(box mir::transform::dump_mir::DumpMir);
 978             passes.push_pass(box mir::transform::simplify::SimplifyCfg::new("initial"));
 979             passes.push_pass(box mir::transform::qualify_consts::QualifyAndPromoteConstants);
 980             passes.push_pass(box mir::transform::type_check::TypeckMir);
 981             passes.push_pass(
 982                 box mir::transform::simplify_branches::SimplifyBranches::new("initial"));
 983             passes.push_pass(box mir::transform::simplify::SimplifyCfg::new("qualify-consts"));
 984             // And run everything.
 985             passes.run_passes(tcx);
 986         });
 987
 988         time(time_passes,
 989              "borrow checking",
 990              || borrowck::check_crate(tcx));
 991
 992         // Avoid overwhelming user with errors if type checking failed.
 993         // I'm not sure how helpful this is, to be honest, but it avoids
 994         // a
 995         // lot of annoying errors in the compile-fail tests (basically,
 996         // lint warnings and so on -- kindck used to do this abort, but
 997         // kindck is gone now). -nmatsakis
 998         if sess.err_count() > 0 {
 999             return Ok(f(tcx, analysis, incremental_hashes_map, Err(sess.err_count())));
1000         }
1001
1002         analysis.reachable =
1003             time(time_passes,
1004                  "reachability checking",
1005                  || reachable::find_reachable(tcx));
1006
1007         time(time_passes, "death checking", || middle::dead::check_crate(tcx));
1008
1009         time(time_passes, "unused lib feature checking", || {
1010             stability::check_unused_or_stable_features(tcx)
1011         });
1012
1013         time(time_passes, "lint checking", || lint::check_crate(tcx));
1014
1015         // The above three passes generate errors w/o aborting
1016         if sess.err_count() > 0 {
1017             return Ok(f(tcx, analysis, incremental_hashes_map, Err(sess.err_count())));
1018         }
1019
1020         Ok(f(tcx, analysis, incremental_hashes_map, Ok(())))
1021     })
1022 }
1023
1024 /// Run the translation phase to LLVM, after which the AST and analysis can
1025 /// be discarded.
1026 pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1027                                            analysis: ty::CrateAnalysis,
1028                                            incremental_hashes_map: &IncrementalHashesMap)
1029                                            -> trans::CrateTranslation {
1030     let time_passes = tcx.sess.time_passes();
1031
1032     time(time_passes,
1033          "resolving dependency formats",
1034          || dependency_format::calculate(&tcx.sess));
1035
1036     if tcx.sess.opts.debugging_opts.mir_stats {
1037         mir_stats::print_mir_stats(tcx, "PRE OPTIMISATION MIR STATS");
1038     }
1039
1040     // Run the passes that transform the MIR into a more suitable form for translation to LLVM
1041     // code.
1042     time(time_passes, "MIR optimisations", || {
1043         let mut passes = ::rustc::mir::transform::Passes::new();
1044         passes.push_hook(box mir::transform::dump_mir::DumpMir);
1045         passes.push_pass(box mir::transform::no_landing_pads::NoLandingPads);
1046         passes.push_pass(box mir::transform::simplify::SimplifyCfg::new("no-landing-pads"));
1047
1048         // From here on out, regions are gone.
1049         passes.push_pass(box mir::transform::erase_regions::EraseRegions);
1050
1051         passes.push_pass(box mir::transform::add_call_guards::AddCallGuards);
1052         passes.push_pass(box borrowck::ElaborateDrops);
1053         passes.push_pass(box mir::transform::no_landing_pads::NoLandingPads);
1054         passes.push_pass(box mir::transform::simplify::SimplifyCfg::new("elaborate-drops"));
1055
1056         // No lifetime analysis based on borrowing can be done from here on out.
1057         passes.push_pass(box mir::transform::inline::Inline);
1058         passes.push_pass(box mir::transform::instcombine::InstCombine::new());
1059         passes.push_pass(box mir::transform::deaggregator::Deaggregator);
1060         passes.push_pass(box mir::transform::copy_prop::CopyPropagation);
1061
1062         passes.push_pass(box mir::transform::simplify::SimplifyLocals);
1063         passes.push_pass(box mir::transform::add_call_guards::AddCallGuards);
1064         passes.push_pass(box mir::transform::dump_mir::Marker("PreTrans"));
1065
1066         passes.run_passes(tcx);
1067     });
1068
1069     if tcx.sess.opts.debugging_opts.mir_stats {
1070         mir_stats::print_mir_stats(tcx, "POST OPTIMISATION MIR STATS");
1071     }
1072
1073     let translation =
1074         time(time_passes,
1075              "translation",
1076              move || trans::trans_crate(tcx, analysis, &incremental_hashes_map));
1077
1078     time(time_passes,
1079          "assert dep graph",
1080          || rustc_incremental::assert_dep_graph(tcx));
1081
1082     time(time_passes,
1083          "serialize dep graph",
1084          || rustc_incremental::save_dep_graph(tcx,
1085                                               &incremental_hashes_map,
1086                                               translation.link.crate_hash));
1087     translation
1088 }
1089
1090 /// Run LLVM itself, producing a bitcode file, assembly file or object file
1091 /// as a side effect.
1092 pub fn phase_5_run_llvm_passes(sess: &Session,
1093                                trans: &trans::CrateTranslation,
1094                                outputs: &OutputFilenames) -> CompileResult {
1095     if sess.opts.cg.no_integrated_as ||
1096         (sess.target.target.options.no_integrated_as &&
1097          (outputs.outputs.contains_key(&OutputType::Object) ||
1098           outputs.outputs.contains_key(&OutputType::Exe)))
1099     {
1100         let output_types = OutputTypes::new(&[(OutputType::Assembly, None)]);
1101         time(sess.time_passes(),
1102              "LLVM passes",
1103              || write::run_passes(sess, trans, &output_types, outputs));
1104
1105         write::run_assembler(sess, outputs);
1106
1107         // HACK the linker expects the object file to be named foo.0.o but
1108         // `run_assembler` produces an object named just foo.o. Rename it if we
1109         // are going to build an executable
1110         if sess.opts.output_types.contains_key(&OutputType::Exe) {
1111             let f = outputs.path(OutputType::Object);
1112             rename_or_copy_remove(&f,
1113                      f.with_file_name(format!("{}.0.o",
1114                                               f.file_stem().unwrap().to_string_lossy()))).unwrap();
1115         }
1116
1117         // Remove assembly source, unless --save-temps was specified
1118         if !sess.opts.cg.save_temps {
1119             fs::remove_file(&outputs.temp_path(OutputType::Assembly, None)).unwrap();
1120         }
1121     } else {
1122         time(sess.time_passes(),
1123              "LLVM passes",
1124              || write::run_passes(sess, trans, &sess.opts.output_types, outputs));
1125     }
1126
1127     time(sess.time_passes(),
1128          "serialize work products",
1129          move || rustc_incremental::save_work_products(sess));
1130
1131     if sess.err_count() > 0 {
1132         Err(sess.err_count())
1133     } else {
1134         Ok(())
1135     }
1136 }
1137
1138 /// Run the linker on any artifacts that resulted from the LLVM run.
1139 /// This should produce either a finished executable or library.
1140 pub fn phase_6_link_output(sess: &Session,
1141                            trans: &trans::CrateTranslation,
1142                            outputs: &OutputFilenames) {
1143     time(sess.time_passes(),
1144          "linking",
1145          || link::link_binary(sess, trans, outputs, &trans.link.crate_name.as_str()));
1146 }
1147
1148 fn escape_dep_filename(filename: &str) -> String {
1149     // Apparently clang and gcc *only* escape spaces:
1150     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
1151     filename.replace(" ", "\\ ")
1152 }
1153
1154 fn write_out_deps(sess: &Session, outputs: &OutputFilenames, crate_name: &str) {
1155     let mut out_filenames = Vec::new();
1156     for output_type in sess.opts.output_types.keys() {
1157         let file = outputs.path(*output_type);
1158         match *output_type {
1159             OutputType::Exe => {
1160                 for output in sess.crate_types.borrow().iter() {
1161                     let p = link::filename_for_input(sess, *output, crate_name, outputs);
1162                     out_filenames.push(p);
1163                 }
1164             }
1165             _ => {
1166                 out_filenames.push(file);
1167             }
1168         }
1169     }
1170
1171     // Write out dependency rules to the dep-info file if requested
1172     if !sess.opts.output_types.contains_key(&OutputType::DepInfo) {
1173         return;
1174     }
1175     let deps_filename = outputs.path(OutputType::DepInfo);
1176
1177     let result =
1178         (|| -> io::Result<()> {
1179             // Build a list of files used to compile the output and
1180             // write Makefile-compatible dependency rules
1181             let files: Vec<String> = sess.codemap()
1182                                          .files
1183                                          .borrow()
1184                                          .iter()
1185                                          .filter(|fmap| fmap.is_real_file())
1186                                          .filter(|fmap| !fmap.is_imported())
1187                                          .map(|fmap| escape_dep_filename(&fmap.name))
1188                                          .collect();
1189             let mut file = fs::File::create(&deps_filename)?;
1190             for path in &out_filenames {
1191                 write!(file, "{}: {}\n\n", path.display(), files.join(" "))?;
1192             }
1193
1194             // Emit a fake target for each input file to the compilation. This
1195             // prevents `make` from spitting out an error if a file is later
1196             // deleted. For more info see #28735
1197             for path in files {
1198                 writeln!(file, "{}:", path)?;
1199             }
1200             Ok(())
1201         })();
1202
1203     match result {
1204         Ok(()) => {}
1205         Err(e) => {
1206             sess.fatal(&format!("error writing dependencies to `{}`: {}",
1207                                 deps_filename.display(),
1208                                 e));
1209         }
1210     }
1211 }
1212
1213 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
1214     // Unconditionally collect crate types from attributes to make them used
1215     let attr_types: Vec<config::CrateType> =
1216         attrs.iter()
1217              .filter_map(|a| {
1218                  if a.check_name("crate_type") {
1219                      match a.value_str() {
1220                          Some(ref n) if *n == "rlib" => {
1221                              Some(config::CrateTypeRlib)
1222                          }
1223                          Some(ref n) if *n == "dylib" => {
1224                              Some(config::CrateTypeDylib)
1225                          }
1226                          Some(ref n) if *n == "cdylib" => {
1227                              Some(config::CrateTypeCdylib)
1228                          }
1229                          Some(ref n) if *n == "lib" => {
1230                              Some(config::default_lib_output())
1231                          }
1232                          Some(ref n) if *n == "staticlib" => {
1233                              Some(config::CrateTypeStaticlib)
1234                          }
1235                          Some(ref n) if *n == "proc-macro" => {
1236                              Some(config::CrateTypeProcMacro)
1237                          }
1238                          Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
1239                          Some(_) => {
1240                              session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
1241                                               ast::CRATE_NODE_ID,
1242                                               a.span,
1243                                               "invalid `crate_type` value".to_string());
1244                              None
1245                          }
1246                          _ => {
1247                              session.struct_span_err(a.span, "`crate_type` requires a value")
1248                                  .note("for example: `#![crate_type=\"lib\"]`")
1249                                  .emit();
1250                              None
1251                          }
1252                      }
1253                  } else {
1254                      None
1255                  }
1256              })
1257              .collect();
1258
1259     // If we're generating a test executable, then ignore all other output
1260     // styles at all other locations
1261     if session.opts.test {
1262         return vec![config::CrateTypeExecutable];
1263     }
1264
1265     // Only check command line flags if present. If no types are specified by
1266     // command line, then reuse the empty `base` Vec to hold the types that
1267     // will be found in crate attributes.
1268     let mut base = session.opts.crate_types.clone();
1269     if base.is_empty() {
1270         base.extend(attr_types);
1271         if base.is_empty() {
1272             base.push(link::default_output_for_target(session));
1273         }
1274         base.sort();
1275         base.dedup();
1276     }
1277
1278     base.into_iter()
1279         .filter(|crate_type| {
1280             let res = !link::invalid_output_for_target(session, *crate_type);
1281
1282             if !res {
1283                 session.warn(&format!("dropping unsupported crate type `{}` for target `{}`",
1284                                       *crate_type,
1285                                       session.opts.target_triple));
1286             }
1287
1288             res
1289         })
1290         .collect()
1291 }
1292
1293 pub fn compute_crate_disambiguator(session: &Session) -> String {
1294     use std::hash::Hasher;
1295
1296     // The crate_disambiguator is a 128 bit hash. The disambiguator is fed
1297     // into various other hashes quite a bit (symbol hashes, incr. comp. hashes,
1298     // debuginfo type IDs, etc), so we don't want it to be too wide. 128 bits
1299     // should still be safe enough to avoid collisions in practice.
1300     // FIXME(mw): It seems that the crate_disambiguator is used everywhere as
1301     //            a hex-string instead of raw bytes. We should really use the
1302     //            smaller representation.
1303     let mut hasher = StableHasher::<Fingerprint>::new();
1304
1305     let mut metadata = session.opts.cg.metadata.clone();
1306     // We don't want the crate_disambiguator to dependent on the order
1307     // -C metadata arguments, so sort them:
1308     metadata.sort();
1309     // Every distinct -C metadata value is only incorporated once:
1310     metadata.dedup();
1311
1312     hasher.write(b"metadata");
1313     for s in &metadata {
1314         // Also incorporate the length of a metadata string, so that we generate
1315         // different values for `-Cmetadata=ab -Cmetadata=c` and
1316         // `-Cmetadata=a -Cmetadata=bc`
1317         hasher.write_usize(s.len());
1318         hasher.write(s.as_bytes());
1319     }
1320
1321     // If this is an executable, add a special suffix, so that we don't get
1322     // symbol conflicts when linking against a library of the same name.
1323     let is_exe = session.crate_types.borrow().contains(&config::CrateTypeExecutable);
1324
1325     format!("{}{}", hasher.finish().to_hex(), if is_exe { "-exe" } else {""})
1326 }
1327
1328 pub fn build_output_filenames(input: &Input,
1329                               odir: &Option<PathBuf>,
1330                               ofile: &Option<PathBuf>,
1331                               attrs: &[ast::Attribute],
1332                               sess: &Session)
1333                               -> OutputFilenames {
1334     match *ofile {
1335         None => {
1336             // "-" as input file will cause the parser to read from stdin so we
1337             // have to make up a name
1338             // We want to toss everything after the final '.'
1339             let dirpath = match *odir {
1340                 Some(ref d) => d.clone(),
1341                 None => PathBuf::new(),
1342             };
1343
1344             // If a crate name is present, we use it as the link name
1345             let stem = sess.opts
1346                            .crate_name
1347                            .clone()
1348                            .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
1349                            .unwrap_or(input.filestem());
1350
1351             OutputFilenames {
1352                 out_directory: dirpath,
1353                 out_filestem: stem,
1354                 single_output_file: None,
1355                 extra: sess.opts.cg.extra_filename.clone(),
1356                 outputs: sess.opts.output_types.clone(),
1357             }
1358         }
1359
1360         Some(ref out_file) => {
1361             let unnamed_output_types = sess.opts
1362                                            .output_types
1363                                            .values()
1364                                            .filter(|a| a.is_none())
1365                                            .count();
1366             let ofile = if unnamed_output_types > 1 {
1367                 sess.warn("due to multiple output types requested, the explicitly specified \
1368                            output file name will be adapted for each output type");
1369                 None
1370             } else {
1371                 Some(out_file.clone())
1372             };
1373             if *odir != None {
1374                 sess.warn("ignoring --out-dir flag due to -o flag.");
1375             }
1376
1377             let cur_dir = Path::new("");
1378
1379             OutputFilenames {
1380                 out_directory: out_file.parent().unwrap_or(cur_dir).to_path_buf(),
1381                 out_filestem: out_file.file_stem()
1382                                       .unwrap_or(OsStr::new(""))
1383                                       .to_str()
1384                                       .unwrap()
1385                                       .to_string(),
1386                 single_output_file: ofile,
1387                 extra: sess.opts.cg.extra_filename.clone(),
1388                 outputs: sess.opts.output_types.clone(),
1389             }
1390         }
1391     }
1392 }