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;
  12 use rustc::hir::{map as hir_map, FreevarMap, TraitMap};
  13 use rustc::hir::def::DefMap;
  14 use rustc::hir::lowering::lower_crate;
  15 use rustc_mir as mir;
  16 use rustc::mir::mir_map::MirMap;
  17 use rustc::session::{Session, CompileResult, compile_result_from_err_count};
  18 use rustc::session::config::{self, Input, OutputFilenames, OutputType,
  19                              OutputTypes};
  20 use rustc::session::search_paths::PathKind;
  21 use rustc::lint;
  22 use rustc::middle::{self, dependency_format, stability, reachable};
  23 use rustc::middle::privacy::AccessLevels;
  24 use rustc::ty::{self, TyCtxt};
  25 use rustc::util::common::time;
  26 use rustc::util::nodemap::NodeSet;
  27 use rustc_back::sha2::{Sha256, Digest};
  28 use rustc_borrowck as borrowck;
  29 use rustc_incremental;
  30 use rustc_resolve::{MakeGlobMap, Resolver};
  31 use rustc_metadata::macro_import;
  32 use rustc_metadata::creader::read_local_crates;
  33 use rustc_metadata::cstore::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, rvalues, static_recursion};
  41 use rustc_const_eval::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::path::{Path, PathBuf};
  51 use syntax::{ast, diagnostics, visit};
  52 use syntax::attr::{self, AttrMetaMethods};
  53 use syntax::parse::{self, PResult, token};
  54 use syntax::util::node_count::NodeCounter;
  55 use syntax;
  56 use syntax_ext;
  57
  58 #[derive(Clone)]
  59 pub struct Resolutions {
  60     pub def_map: DefMap,
  61     pub freevars: FreevarMap,
  62     pub trait_map: TraitMap,
  63     pub maybe_unused_trait_imports: NodeSet,
  64 }
  65
  66 pub fn compile_input(sess: &Session,
  67                      cstore: &CStore,
  68                      cfg: ast::CrateConfig,
  69                      input: &Input,
  70                      outdir: &Option<PathBuf>,
  71                      output: &Option<PathBuf>,
  72                      addl_plugins: Option<Vec<String>>,
  73                      control: &CompileController) -> CompileResult {
  74     macro_rules! controller_entry_point {
  75         ($point: ident, $tsess: expr, $make_state: expr, $phase_result: expr) => {{
  76             let state = &mut $make_state;
  77             let phase_result: &CompileResult = &$phase_result;
  78             if phase_result.is_ok() || control.$point.run_callback_on_error {
  79                 (control.$point.callback)(state);
  80             }
  81
  82             if control.$point.stop == Compilation::Stop {
  83                 return compile_result_from_err_count($tsess.err_count());
  84             }
  85         }}
  86     }
  87
  88     // We need nested scopes here, because the intermediate results can keep
  89     // large chunks of memory alive and we want to free them as soon as
  90     // possible to keep the peak memory usage low
  91     let (outputs, trans, crate_name) = {
  92         let krate = match phase_1_parse_input(sess, cfg, input) {
  93             Ok(krate) => krate,
  94             Err(mut parse_error) => {
  95                 parse_error.emit();
  96                 return Err(1);
  97             }
  98         };
  99
 100         let krate = {
 101             let mut compile_state = CompileState::state_after_parse(input,
 102                                                                     sess,
 103                                                                     outdir,
 104                                                                     output,
 105                                                                     krate,
 106                                                                     &cstore);
 107             controller_entry_point!(after_parse,
 108                                     sess,
 109                                     compile_state,
 110                                     Ok(()));
 111
 112             compile_state.krate.unwrap()
 113         };
 114
 115         let outputs = build_output_filenames(input, outdir, output, &krate.attrs, sess);
 116         let crate_name = link::find_crate_name(Some(sess), &krate.attrs, input);
 117         let ExpansionResult { expanded_crate, defs, analysis, resolutions, mut hir_forest } = {
 118             phase_2_configure_and_expand(
 119                 sess, &cstore, krate, &crate_name, addl_plugins, control.make_glob_map,
 120                 |expanded_crate| {
 121                     let mut state = CompileState::state_after_expand(
 122                         input, sess, outdir, output, &cstore, expanded_crate, &crate_name,
 123                     );
 124                     controller_entry_point!(after_expand, sess, state, Ok(()));
 125                     Ok(())
 126                 }
 127             )?
 128         };
 129
 130         write_out_deps(sess, &outputs, &crate_name);
 131
 132         let arenas = ty::CtxtArenas::new();
 133
 134         // Construct the HIR map
 135         let hir_map = time(sess.time_passes(),
 136                            "indexing hir",
 137                            || hir_map::map_crate(&mut hir_forest, defs));
 138
 139         {
 140             let _ignore = hir_map.dep_graph.in_ignore();
 141             controller_entry_point!(after_hir_lowering,
 142                                     sess,
 143                                     CompileState::state_after_hir_lowering(input,
 144                                                                   sess,
 145                                                                   outdir,
 146                                                                   output,
 147                                                                   &arenas,
 148                                                                   &cstore,
 149                                                                   &hir_map,
 150                                                                   &analysis,
 151                                                                   &resolutions,
 152                                                                   &expanded_crate,
 153                                                                   &hir_map.krate(),
 154                                                                   &crate_name),
 155                                     Ok(()));
 156         }
 157
 158         time(sess.time_passes(), "attribute checking", || {
 159             hir::check_attr::check_crate(sess, &expanded_crate);
 160         });
 161
 162         let opt_crate = if keep_ast(sess) {
 163             Some(&expanded_crate)
 164         } else {
 165             drop(expanded_crate);
 166             None
 167         };
 168
 169         phase_3_run_analysis_passes(sess,
 170                                     hir_map,
 171                                     analysis,
 172                                     resolutions,
 173                                     &arenas,
 174                                     &crate_name,
 175                                     |tcx, mir_map, analysis, result| {
 176             {
 177                 // Eventually, we will want to track plugins.
 178                 let _ignore = tcx.dep_graph.in_ignore();
 179
 180                 let mut state = CompileState::state_after_analysis(input,
 181                                                                    sess,
 182                                                                    outdir,
 183                                                                    output,
 184                                                                    opt_crate,
 185                                                                    tcx.map.krate(),
 186                                                                    &analysis,
 187                                                                    mir_map.as_ref(),
 188                                                                    tcx,
 189                                                                    &crate_name);
 190                 (control.after_analysis.callback)(&mut state);
 191
 192                 if control.after_analysis.stop == Compilation::Stop {
 193                     return result.and_then(|_| Err(0usize));
 194                 }
 195             }
 196
 197             result?;
 198
 199             if log_enabled!(::log::INFO) {
 200                 println!("Pre-trans");
 201                 tcx.print_debug_stats();
 202             }
 203             let trans = phase_4_translate_to_llvm(tcx,
 204                                                   mir_map.unwrap(),
 205                                                   analysis);
 206
 207             if log_enabled!(::log::INFO) {
 208                 println!("Post-trans");
 209                 tcx.print_debug_stats();
 210             }
 211
 212             // Discard interned strings as they are no longer required.
 213             token::clear_ident_interner();
 214
 215             Ok((outputs, trans, crate_name.clone()))
 216         })??
 217     };
 218
 219     let phase5_result = phase_5_run_llvm_passes(sess, &crate_name, &trans, &outputs);
 220
 221     controller_entry_point!(after_llvm,
 222                             sess,
 223                             CompileState::state_after_llvm(input, sess, outdir, output, &trans),
 224                             phase5_result);
 225     phase5_result?;
 226
 227     write::cleanup_llvm(&trans);
 228
 229     phase_6_link_output(sess, &trans, &outputs);
 230
 231     controller_entry_point!(compilation_done,
 232                             sess,
 233                             CompileState::state_when_compilation_done(input, sess, outdir, output),
 234                             Ok(()));
 235
 236     Ok(())
 237 }
 238
 239 fn keep_hygiene_data(sess: &Session) -> bool {
 240     sess.opts.debugging_opts.keep_hygiene_data
 241 }
 242
 243 fn keep_ast(sess: &Session) -> bool {
 244     sess.opts.debugging_opts.keep_ast ||
 245     sess.opts.debugging_opts.save_analysis ||
 246     sess.opts.debugging_opts.save_analysis_csv
 247 }
 248
 249 /// The name used for source code that doesn't originate in a file
 250 /// (e.g. source from stdin or a string)
 251 pub fn anon_src() -> String {
 252     "<anon>".to_string()
 253 }
 254
 255 pub fn source_name(input: &Input) -> String {
 256     match *input {
 257         // FIXME (#9639): This needs to handle non-utf8 paths
 258         Input::File(ref ifile) => ifile.to_str().unwrap().to_string(),
 259         Input::Str { ref name, .. } => name.clone(),
 260     }
 261 }
 262
 263 /// CompileController is used to customise compilation, it allows compilation to
 264 /// be stopped and/or to call arbitrary code at various points in compilation.
 265 /// It also allows for various flags to be set to influence what information gets
 266 /// collected during compilation.
 267 ///
 268 /// This is a somewhat higher level controller than a Session - the Session
 269 /// controls what happens in each phase, whereas the CompileController controls
 270 /// whether a phase is run at all and whether other code (from outside the
 271 /// the compiler) is run between phases.
 272 ///
 273 /// Note that if compilation is set to stop and a callback is provided for a
 274 /// given entry point, the callback is called before compilation is stopped.
 275 ///
 276 /// Expect more entry points to be added in the future.
 277 pub struct CompileController<'a> {
 278     pub after_parse: PhaseController<'a>,
 279     pub after_expand: PhaseController<'a>,
 280     pub after_hir_lowering: PhaseController<'a>,
 281     pub after_analysis: PhaseController<'a>,
 282     pub after_llvm: PhaseController<'a>,
 283     pub compilation_done: PhaseController<'a>,
 284
 285     pub make_glob_map: MakeGlobMap,
 286 }
 287
 288 impl<'a> CompileController<'a> {
 289     pub fn basic() -> CompileController<'a> {
 290         CompileController {
 291             after_parse: PhaseController::basic(),
 292             after_expand: PhaseController::basic(),
 293             after_hir_lowering: PhaseController::basic(),
 294             after_analysis: PhaseController::basic(),
 295             after_llvm: PhaseController::basic(),
 296             compilation_done: PhaseController::basic(),
 297             make_glob_map: MakeGlobMap::No,
 298         }
 299     }
 300 }
 301
 302 pub struct PhaseController<'a> {
 303     pub stop: Compilation,
 304     // If true then the compiler will try to run the callback even if the phase
 305     // ends with an error. Note that this is not always possible.
 306     pub run_callback_on_error: bool,
 307     pub callback: Box<Fn(&mut CompileState) + 'a>,
 308 }
 309
 310 impl<'a> PhaseController<'a> {
 311     pub fn basic() -> PhaseController<'a> {
 312         PhaseController {
 313             stop: Compilation::Continue,
 314             run_callback_on_error: false,
 315             callback: box |_| {},
 316         }
 317     }
 318 }
 319
 320 /// State that is passed to a callback. What state is available depends on when
 321 /// during compilation the callback is made. See the various constructor methods
 322 /// (`state_*`) in the impl to see which data is provided for any given entry point.
 323 pub struct CompileState<'a, 'b, 'ast: 'a, 'tcx: 'b> where 'ast: 'tcx {
 324     pub input: &'a Input,
 325     pub session: &'ast Session,
 326     pub krate: Option<ast::Crate>,
 327     pub cstore: Option<&'a CStore>,
 328     pub crate_name: Option<&'a str>,
 329     pub output_filenames: Option<&'a OutputFilenames>,
 330     pub out_dir: Option<&'a Path>,
 331     pub out_file: Option<&'a Path>,
 332     pub arenas: Option<&'ast ty::CtxtArenas<'ast>>,
 333     pub expanded_crate: Option<&'a ast::Crate>,
 334     pub hir_crate: Option<&'a hir::Crate>,
 335     pub ast_map: Option<&'a hir_map::Map<'ast>>,
 336     pub resolutions: Option<&'a Resolutions>,
 337     pub mir_map: Option<&'b MirMap<'tcx>>,
 338     pub analysis: Option<&'a ty::CrateAnalysis<'a>>,
 339     pub tcx: Option<TyCtxt<'b, 'tcx, 'tcx>>,
 340     pub trans: Option<&'a trans::CrateTranslation>,
 341 }
 342
 343 impl<'a, 'b, 'ast, 'tcx> CompileState<'a, 'b, 'ast, 'tcx> {
 344     fn empty(input: &'a Input,
 345              session: &'ast Session,
 346              out_dir: &'a Option<PathBuf>)
 347              -> CompileState<'a, 'b, 'ast, 'tcx> {
 348         CompileState {
 349             input: input,
 350             session: session,
 351             out_dir: out_dir.as_ref().map(|s| &**s),
 352             out_file: None,
 353             arenas: None,
 354             krate: None,
 355             cstore: None,
 356             crate_name: None,
 357             output_filenames: None,
 358             expanded_crate: None,
 359             hir_crate: None,
 360             ast_map: None,
 361             resolutions: None,
 362             analysis: None,
 363             mir_map: None,
 364             tcx: None,
 365             trans: None,
 366         }
 367     }
 368
 369     fn state_after_parse(input: &'a Input,
 370                          session: &'ast Session,
 371                          out_dir: &'a Option<PathBuf>,
 372                          out_file: &'a Option<PathBuf>,
 373                          krate: ast::Crate,
 374                          cstore: &'a CStore)
 375                          -> CompileState<'a, 'b, 'ast, 'tcx> {
 376         CompileState {
 377             krate: Some(krate),
 378             cstore: Some(cstore),
 379             out_file: out_file.as_ref().map(|s| &**s),
 380             ..CompileState::empty(input, session, out_dir)
 381         }
 382     }
 383
 384     fn state_after_expand(input: &'a Input,
 385                           session: &'ast Session,
 386                           out_dir: &'a Option<PathBuf>,
 387                           out_file: &'a Option<PathBuf>,
 388                           cstore: &'a CStore,
 389                           expanded_crate: &'a ast::Crate,
 390                           crate_name: &'a str)
 391                           -> CompileState<'a, 'b, 'ast, 'tcx> {
 392         CompileState {
 393             crate_name: Some(crate_name),
 394             cstore: Some(cstore),
 395             expanded_crate: Some(expanded_crate),
 396             out_file: out_file.as_ref().map(|s| &**s),
 397             ..CompileState::empty(input, session, out_dir)
 398         }
 399     }
 400
 401     fn state_after_hir_lowering(input: &'a Input,
 402                                 session: &'ast Session,
 403                                 out_dir: &'a Option<PathBuf>,
 404                                 out_file: &'a Option<PathBuf>,
 405                                 arenas: &'ast ty::CtxtArenas<'ast>,
 406                                 cstore: &'a CStore,
 407                                 hir_map: &'a hir_map::Map<'ast>,
 408                                 analysis: &'a ty::CrateAnalysis,
 409                                 resolutions: &'a Resolutions,
 410                                 krate: &'a ast::Crate,
 411                                 hir_crate: &'a hir::Crate,
 412                                 crate_name: &'a str)
 413                                 -> CompileState<'a, 'b, 'ast, 'tcx> {
 414         CompileState {
 415             crate_name: Some(crate_name),
 416             arenas: Some(arenas),
 417             cstore: Some(cstore),
 418             ast_map: Some(hir_map),
 419             analysis: Some(analysis),
 420             resolutions: Some(resolutions),
 421             expanded_crate: Some(krate),
 422             hir_crate: Some(hir_crate),
 423             out_file: out_file.as_ref().map(|s| &**s),
 424             ..CompileState::empty(input, session, out_dir)
 425         }
 426     }
 427
 428     fn state_after_analysis(input: &'a Input,
 429                             session: &'ast Session,
 430                             out_dir: &'a Option<PathBuf>,
 431                             out_file: &'a Option<PathBuf>,
 432                             krate: Option<&'a ast::Crate>,
 433                             hir_crate: &'a hir::Crate,
 434                             analysis: &'a ty::CrateAnalysis<'a>,
 435                             mir_map: Option<&'b MirMap<'tcx>>,
 436                             tcx: TyCtxt<'b, 'tcx, 'tcx>,
 437                             crate_name: &'a str)
 438                             -> CompileState<'a, 'b, 'ast, 'tcx> {
 439         CompileState {
 440             analysis: Some(analysis),
 441             mir_map: mir_map,
 442             tcx: Some(tcx),
 443             expanded_crate: krate,
 444             hir_crate: Some(hir_crate),
 445             crate_name: Some(crate_name),
 446             out_file: out_file.as_ref().map(|s| &**s),
 447             ..CompileState::empty(input, session, out_dir)
 448         }
 449     }
 450
 451
 452     fn state_after_llvm(input: &'a Input,
 453                         session: &'ast Session,
 454                         out_dir: &'a Option<PathBuf>,
 455                         out_file: &'a Option<PathBuf>,
 456                         trans: &'a trans::CrateTranslation)
 457                         -> CompileState<'a, 'b, 'ast, 'tcx> {
 458         CompileState {
 459             trans: Some(trans),
 460             out_file: out_file.as_ref().map(|s| &**s),
 461             ..CompileState::empty(input, session, out_dir)
 462         }
 463     }
 464
 465     fn state_when_compilation_done(input: &'a Input,
 466                                     session: &'ast Session,
 467                                     out_dir: &'a Option<PathBuf>,
 468                                     out_file: &'a Option<PathBuf>)
 469                                     -> CompileState<'a, 'b, 'ast, 'tcx> {
 470         CompileState {
 471             out_file: out_file.as_ref().map(|s| &**s),
 472             ..CompileState::empty(input, session, out_dir)
 473         }
 474     }
 475 }
 476
 477 pub fn phase_1_parse_input<'a>(sess: &'a Session,
 478                                cfg: ast::CrateConfig,
 479                                input: &Input)
 480                                -> PResult<'a, ast::Crate> {
 481     let continue_after_error = sess.opts.debugging_opts.continue_parse_after_error;
 482     sess.diagnostic().set_continue_after_error(continue_after_error);
 483
 484     let krate = time(sess.time_passes(), "parsing", || {
 485         match *input {
 486             Input::File(ref file) => {
 487                 parse::parse_crate_from_file(file, cfg.clone(), &sess.parse_sess)
 488             }
 489             Input::Str { ref input, ref name } => {
 490                 parse::parse_crate_from_source_str(name.clone(),
 491                                                    input.clone(),
 492                                                    cfg.clone(),
 493                                                    &sess.parse_sess)
 494             }
 495         }
 496     })?;
 497
 498     sess.diagnostic().set_continue_after_error(true);
 499
 500     if sess.opts.debugging_opts.ast_json_noexpand {
 501         println!("{}", json::as_json(&krate));
 502     }
 503
 504     if sess.opts.debugging_opts.input_stats {
 505         println!("Lines of code:             {}", sess.codemap().count_lines());
 506         println!("Pre-expansion node count:  {}", count_nodes(&krate));
 507     }
 508
 509     if let Some(ref s) = sess.opts.debugging_opts.show_span {
 510         syntax::show_span::run(sess.diagnostic(), s, &krate);
 511     }
 512
 513     Ok(krate)
 514 }
 515
 516 fn count_nodes(krate: &ast::Crate) -> usize {
 517     let mut counter = NodeCounter::new();
 518     visit::walk_crate(&mut counter, krate);
 519     counter.count
 520 }
 521
 522 // For continuing compilation after a parsed crate has been
 523 // modified
 524
 525 pub struct ExpansionResult<'a> {
 526     pub expanded_crate: ast::Crate,
 527     pub defs: hir_map::Definitions,
 528     pub analysis: ty::CrateAnalysis<'a>,
 529     pub resolutions: Resolutions,
 530     pub hir_forest: hir_map::Forest,
 531 }
 532
 533 /// Run the "early phases" of the compiler: initial `cfg` processing,
 534 /// loading compiler plugins (including those from `addl_plugins`),
 535 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 536 /// harness if one is to be provided, injection of a dependency on the
 537 /// standard library and prelude, and name resolution.
 538 ///
 539 /// Returns `None` if we're aborting after handling -W help.
 540 pub fn phase_2_configure_and_expand<'a, F>(sess: &Session,
 541                                            cstore: &CStore,
 542                                            mut krate: ast::Crate,
 543                                            crate_name: &'a str,
 544                                            addl_plugins: Option<Vec<String>>,
 545                                            make_glob_map: MakeGlobMap,
 546                                            after_expand: F)
 547                                            -> Result<ExpansionResult<'a>, usize>
 548     where F: FnOnce(&ast::Crate) -> CompileResult,
 549 {
 550     let time_passes = sess.time_passes();
 551
 552     // strip before anything else because crate metadata may use #[cfg_attr]
 553     // and so macros can depend on configuration variables, such as
 554     //
 555     //   #[macro_use] #[cfg(foo)]
 556     //   mod bar { macro_rules! baz!(() => {{}}) }
 557     //
 558     // baz! should not use this definition unless foo is enabled.
 559
 560     krate = time(time_passes, "configuration", || {
 561         let (krate, features) =
 562             syntax::config::strip_unconfigured_items(krate, &sess.parse_sess, sess.opts.test);
 563         // these need to be set "early" so that expansion sees `quote` if enabled.
 564         *sess.features.borrow_mut() = features;
 565         krate
 566     });
 567
 568     *sess.crate_types.borrow_mut() = collect_crate_types(sess, &krate.attrs);
 569     *sess.crate_disambiguator.borrow_mut() =
 570         token::intern(&compute_crate_disambiguator(sess)).as_str();
 571
 572     time(time_passes, "recursion limit", || {
 573         middle::recursion_limit::update_recursion_limit(sess, &krate);
 574     });
 575
 576     krate = time(time_passes, "crate injection", || {
 577         let alt_std_name = sess.opts.alt_std_name.clone();
 578         syntax::std_inject::maybe_inject_crates_ref(&sess.parse_sess, krate, alt_std_name)
 579     });
 580
 581     let mut addl_plugins = Some(addl_plugins);
 582     let registrars = time(time_passes, "plugin loading", || {
 583         plugin::load::load_plugins(sess,
 584                                    &cstore,
 585                                    &krate,
 586                                    crate_name,
 587                                    addl_plugins.take().unwrap())
 588     });
 589
 590     let mut registry = Registry::new(sess, &krate);
 591
 592     time(time_passes, "plugin registration", || {
 593         if sess.features.borrow().rustc_diagnostic_macros {
 594             registry.register_macro("__diagnostic_used",
 595                                     diagnostics::plugin::expand_diagnostic_used);
 596             registry.register_macro("__register_diagnostic",
 597                                     diagnostics::plugin::expand_register_diagnostic);
 598             registry.register_macro("__build_diagnostic_array",
 599                                     diagnostics::plugin::expand_build_diagnostic_array);
 600         }
 601
 602         for registrar in registrars {
 603             registry.args_hidden = Some(registrar.args);
 604             (registrar.fun)(&mut registry);
 605         }
 606     });
 607
 608     let Registry { syntax_exts, early_lint_passes, late_lint_passes, lint_groups,
 609                    llvm_passes, attributes, mir_passes, .. } = registry;
 610
 611     sess.track_errors(|| {
 612         let mut ls = sess.lint_store.borrow_mut();
 613         for pass in early_lint_passes {
 614             ls.register_early_pass(Some(sess), true, pass);
 615         }
 616         for pass in late_lint_passes {
 617             ls.register_late_pass(Some(sess), true, pass);
 618         }
 619
 620         for (name, to) in lint_groups {
 621             ls.register_group(Some(sess), true, name, to);
 622         }
 623
 624         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
 625         sess.mir_passes.borrow_mut().extend(mir_passes);
 626         *sess.plugin_attributes.borrow_mut() = attributes.clone();
 627     })?;
 628
 629     // Lint plugins are registered; now we can process command line flags.
 630     if sess.opts.describe_lints {
 631         super::describe_lints(&sess.lint_store.borrow(), true);
 632         return Err(0);
 633     }
 634     sess.track_errors(|| sess.lint_store.borrow_mut().process_command_line(sess))?;
 635
 636     krate = time(time_passes, "expansion", || {
 637         // Windows dlls do not have rpaths, so they don't know how to find their
 638         // dependencies. It's up to us to tell the system where to find all the
 639         // dependent dlls. Note that this uses cfg!(windows) as opposed to
 640         // targ_cfg because syntax extensions are always loaded for the host
 641         // compiler, not for the target.
 642         //
 643         // This is somewhat of an inherently racy operation, however, as
 644         // multiple threads calling this function could possibly continue
 645         // extending PATH far beyond what it should. To solve this for now we
 646         // just don't add any new elements to PATH which are already there
 647         // within PATH. This is basically a targeted fix at #17360 for rustdoc
 648         // which runs rustc in parallel but has been seen (#33844) to cause
 649         // problems with PATH becoming too long.
 650         let mut old_path = OsString::new();
 651         if cfg!(windows) {
 652             old_path = env::var_os("PATH").unwrap_or(old_path);
 653             let mut new_path = sess.host_filesearch(PathKind::All)
 654                                    .get_dylib_search_paths();
 655             for path in env::split_paths(&old_path) {
 656                 if !new_path.contains(&path) {
 657                     new_path.push(path);
 658                 }
 659             }
 660             env::set_var("PATH", &env::join_paths(new_path).unwrap());
 661         }
 662         let features = sess.features.borrow();
 663         let cfg = syntax::ext::expand::ExpansionConfig {
 664             crate_name: crate_name.to_string(),
 665             features: Some(&features),
 666             recursion_limit: sess.recursion_limit.get(),
 667             trace_mac: sess.opts.debugging_opts.trace_macros,
 668             should_test: sess.opts.test,
 669         };
 670         let mut loader = macro_import::MacroLoader::new(sess,
 671                                                         &cstore,
 672                                                         crate_name,
 673                                                         krate.config.clone());
 674         let mut ecx = syntax::ext::base::ExtCtxt::new(&sess.parse_sess,
 675                                                       krate.config.clone(),
 676                                                       cfg,
 677                                                       &mut loader);
 678         syntax_ext::register_builtins(&mut ecx.syntax_env);
 679         let ret = syntax::ext::expand::expand_crate(&mut ecx, syntax_exts, krate);
 680         if cfg!(windows) {
 681             env::set_var("PATH", &old_path);
 682         }
 683         *sess.available_macros.borrow_mut() = ecx.syntax_env.names;
 684         ret
 685     });
 686
 687     krate = time(time_passes, "maybe building test harness", || {
 688         syntax::test::modify_for_testing(&sess.parse_sess,
 689                                          sess.opts.test,
 690                                          krate,
 691                                          sess.diagnostic())
 692     });
 693
 694     let resolver_arenas = Resolver::arenas();
 695     let mut resolver = Resolver::new(sess, make_glob_map, &resolver_arenas);
 696
 697     let krate = time(sess.time_passes(), "assigning node ids", || resolver.assign_node_ids(krate));
 698
 699     if sess.opts.debugging_opts.input_stats {
 700         println!("Post-expansion node count: {}", count_nodes(&krate));
 701     }
 702
 703     if sess.opts.debugging_opts.ast_json {
 704         println!("{}", json::as_json(&krate));
 705     }
 706
 707     time(time_passes,
 708          "checking for inline asm in case the target doesn't support it",
 709          || no_asm::check_crate(sess, &krate));
 710
 711     // Needs to go *after* expansion to be able to check the results of macro expansion.
 712     time(time_passes, "complete gated feature checking", || {
 713         sess.track_errors(|| {
 714             syntax::feature_gate::check_crate(&krate,
 715                                               &sess.parse_sess,
 716                                               &sess.features.borrow(),
 717                                               &attributes,
 718                                               sess.opts.unstable_features);
 719         })
 720     })?;
 721
 722     // Collect defintions for def ids.
 723     time(sess.time_passes(), "collecting defs", || resolver.definitions.collect(&krate));
 724
 725     time(sess.time_passes(), "external crate/lib resolution", || {
 726         let defs = &resolver.definitions;
 727         read_local_crates(sess, &cstore, defs, &krate, crate_name, &sess.dep_graph)
 728     });
 729
 730     time(sess.time_passes(),
 731          "early lint checks",
 732          || lint::check_ast_crate(sess, &krate));
 733
 734     time(sess.time_passes(),
 735          "AST validation",
 736          || ast_validation::check_crate(sess, &krate));
 737
 738     time(sess.time_passes(), "name resolution", || -> CompileResult {
 739         // Currently, we ignore the name resolution data structures for the purposes of dependency
 740         // tracking. Instead we will run name resolution and include its output in the hash of each
 741         // item, much like we do for macro expansion. In other words, the hash reflects not just
 742         // its contents but the results of name resolution on those contents. Hopefully we'll push
 743         // this back at some point.
 744         let _ignore = sess.dep_graph.in_ignore();
 745         resolver.build_reduced_graph(&krate);
 746         resolver.resolve_imports();
 747
 748         // Since import resolution will eventually happen in expansion,
 749         // don't perform `after_expand` until after import resolution.
 750         after_expand(&krate)?;
 751
 752         resolver.resolve_crate(&krate);
 753         Ok(())
 754     })?;
 755
 756     // Lower ast -> hir.
 757     let hir_forest = time(sess.time_passes(), "lowering ast -> hir", || {
 758         hir_map::Forest::new(lower_crate(sess, &krate, &mut resolver), &sess.dep_graph)
 759     });
 760
 761     // Discard hygiene data, which isn't required past lowering to HIR.
 762     if !keep_hygiene_data(sess) {
 763         syntax::ext::hygiene::reset_hygiene_data();
 764     }
 765
 766     Ok(ExpansionResult {
 767         expanded_crate: krate,
 768         defs: resolver.definitions,
 769         analysis: ty::CrateAnalysis {
 770             export_map: resolver.export_map,
 771             access_levels: AccessLevels::default(),
 772             reachable: NodeSet(),
 773             name: crate_name,
 774             glob_map: if resolver.make_glob_map { Some(resolver.glob_map) } else { None },
 775         },
 776         resolutions: Resolutions {
 777             def_map: resolver.def_map,
 778             freevars: resolver.freevars,
 779             trait_map: resolver.trait_map,
 780             maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
 781         },
 782         hir_forest: hir_forest
 783     })
 784 }
 785
 786 /// Run the resolution, typechecking, region checking and other
 787 /// miscellaneous analysis passes on the crate. Return various
 788 /// structures carrying the results of the analysis.
 789 pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 790                                                hir_map: hir_map::Map<'tcx>,
 791                                                mut analysis: ty::CrateAnalysis,
 792                                                resolutions: Resolutions,
 793                                                arenas: &'tcx ty::CtxtArenas<'tcx>,
 794                                                name: &str,
 795                                                f: F)
 796                                                -> Result<R, usize>
 797     where F: for<'a> FnOnce(TyCtxt<'a, 'tcx, 'tcx>,
 798                             Option<MirMap<'tcx>>,
 799                             ty::CrateAnalysis,
 800                             CompileResult) -> R
 801 {
 802     macro_rules! try_with_f {
 803         ($e: expr, ($t: expr, $m: expr, $a: expr)) => {
 804             match $e {
 805                 Ok(x) => x,
 806                 Err(x) => {
 807                     f($t, $m, $a, Err(x));
 808                     return Err(x);
 809                 }
 810             }
 811         }
 812     }
 813
 814     let time_passes = sess.time_passes();
 815
 816     let lang_items = time(time_passes, "language item collection", || {
 817         sess.track_errors(|| {
 818             middle::lang_items::collect_language_items(&sess, &hir_map)
 819         })
 820     })?;
 821
 822     let named_region_map = time(time_passes,
 823                                 "lifetime resolution",
 824                                 || middle::resolve_lifetime::krate(sess,
 825                                                                    &hir_map,
 826                                                                    &resolutions.def_map))?;
 827
 828     time(time_passes,
 829          "looking for entry point",
 830          || middle::entry::find_entry_point(sess, &hir_map));
 831
 832     sess.plugin_registrar_fn.set(time(time_passes, "looking for plugin registrar", || {
 833         plugin::build::find_plugin_registrar(sess.diagnostic(), &hir_map)
 834     }));
 835
 836     let region_map = time(time_passes,
 837                           "region resolution",
 838                           || middle::region::resolve_crate(sess, &hir_map));
 839
 840     time(time_passes,
 841          "loop checking",
 842          || loops::check_crate(sess, &hir_map));
 843
 844     time(time_passes,
 845               "static item recursion checking",
 846               || static_recursion::check_crate(sess, &resolutions.def_map, &hir_map))?;
 847
 848     let index = stability::Index::new(&hir_map);
 849
 850     TyCtxt::create_and_enter(sess,
 851                              arenas,
 852                              resolutions.def_map,
 853                              resolutions.trait_map,
 854                              named_region_map,
 855                              hir_map,
 856                              resolutions.freevars,
 857                              resolutions.maybe_unused_trait_imports,
 858                              region_map,
 859                              lang_items,
 860                              index,
 861                              name,
 862                              |tcx| {
 863         time(time_passes,
 864              "load_dep_graph",
 865              || rustc_incremental::load_dep_graph(tcx));
 866
 867         // passes are timed inside typeck
 868         try_with_f!(typeck::check_crate(tcx), (tcx, None, analysis));
 869
 870         time(time_passes,
 871              "const checking",
 872              || consts::check_crate(tcx));
 873
 874         analysis.access_levels =
 875             time(time_passes, "privacy checking", || {
 876                 rustc_privacy::check_crate(tcx, &analysis.export_map)
 877             });
 878
 879         // Do not move this check past lint
 880         time(time_passes, "stability index", || {
 881             tcx.stability.borrow_mut().build(tcx, &analysis.access_levels)
 882         });
 883
 884         time(time_passes,
 885              "intrinsic checking",
 886              || middle::intrinsicck::check_crate(tcx));
 887
 888         time(time_passes,
 889              "effect checking",
 890              || middle::effect::check_crate(tcx));
 891
 892         time(time_passes,
 893              "match checking",
 894              || check_match::check_crate(tcx));
 895
 896         // this must run before MIR dump, because
 897         // "not all control paths return a value" is reported here.
 898         //
 899         // maybe move the check to a MIR pass?
 900         time(time_passes,
 901              "liveness checking",
 902              || middle::liveness::check_crate(tcx));
 903
 904         time(time_passes,
 905              "rvalue checking",
 906              || rvalues::check_crate(tcx));
 907
 908         let mut mir_map =
 909             time(time_passes,
 910                  "MIR dump",
 911                  || mir::mir_map::build_mir_for_crate(tcx));
 912
 913         time(time_passes, "MIR passes", || {
 914             let mut passes = sess.mir_passes.borrow_mut();
 915             // Push all the built-in passes.
 916             passes.push_hook(box mir::transform::dump_mir::DumpMir);
 917             passes.push_pass(box mir::transform::simplify_cfg::SimplifyCfg::new("initial"));
 918             passes.push_pass(box mir::transform::qualify_consts::QualifyAndPromoteConstants);
 919             passes.push_pass(box mir::transform::type_check::TypeckMir);
 920             passes.push_pass(
 921                 box mir::transform::simplify_branches::SimplifyBranches::new("initial"));
 922             passes.push_pass(box mir::transform::simplify_cfg::SimplifyCfg::new("qualify-consts"));
 923             // And run everything.
 924             passes.run_passes(tcx, &mut mir_map);
 925         });
 926
 927         time(time_passes,
 928              "borrow checking",
 929              || borrowck::check_crate(tcx, &mir_map));
 930
 931         // Avoid overwhelming user with errors if type checking failed.
 932         // I'm not sure how helpful this is, to be honest, but it avoids
 933         // a
 934         // lot of annoying errors in the compile-fail tests (basically,
 935         // lint warnings and so on -- kindck used to do this abort, but
 936         // kindck is gone now). -nmatsakis
 937         if sess.err_count() > 0 {
 938             return Ok(f(tcx, Some(mir_map), analysis, Err(sess.err_count())));
 939         }
 940
 941         analysis.reachable =
 942             time(time_passes,
 943                  "reachability checking",
 944                  || reachable::find_reachable(tcx, &analysis.access_levels));
 945
 946         time(time_passes, "death checking", || {
 947             middle::dead::check_crate(tcx, &analysis.access_levels);
 948         });
 949
 950         let ref lib_features_used =
 951             time(time_passes,
 952                  "stability checking",
 953                  || stability::check_unstable_api_usage(tcx));
 954
 955         time(time_passes, "unused lib feature checking", || {
 956             stability::check_unused_or_stable_features(&tcx.sess,
 957                                                        lib_features_used)
 958         });
 959
 960         time(time_passes,
 961              "lint checking",
 962              || lint::check_crate(tcx, &analysis.access_levels));
 963
 964         // The above three passes generate errors w/o aborting
 965         if sess.err_count() > 0 {
 966             return Ok(f(tcx, Some(mir_map), analysis, Err(sess.err_count())));
 967         }
 968
 969         Ok(f(tcx, Some(mir_map), analysis, Ok(())))
 970     })
 971 }
 972
 973 /// Run the translation phase to LLVM, after which the AST and analysis can
 974 pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 975                                            mut mir_map: MirMap<'tcx>,
 976                                            analysis: ty::CrateAnalysis)
 977                                            -> trans::CrateTranslation {
 978     let time_passes = tcx.sess.time_passes();
 979
 980     time(time_passes,
 981          "resolving dependency formats",
 982          || dependency_format::calculate(&tcx.sess));
 983
 984     // Run the passes that transform the MIR into a more suitable for translation
 985     // to LLVM code.
 986     time(time_passes, "Prepare MIR codegen passes", || {
 987         let mut passes = ::rustc::mir::transform::Passes::new();
 988         passes.push_hook(box mir::transform::dump_mir::DumpMir);
 989         passes.push_pass(box mir::transform::no_landing_pads::NoLandingPads);
 990         passes.push_pass(box mir::transform::simplify_cfg::SimplifyCfg::new("no-landing-pads"));
 991
 992         passes.push_pass(box mir::transform::erase_regions::EraseRegions);
 993
 994         passes.push_pass(box mir::transform::add_call_guards::AddCallGuards);
 995         passes.push_pass(box borrowck::ElaborateDrops);
 996         passes.push_pass(box mir::transform::no_landing_pads::NoLandingPads);
 997         passes.push_pass(box mir::transform::simplify_cfg::SimplifyCfg::new("elaborate-drops"));
 998
 999         passes.push_pass(box mir::transform::deaggregator::Deaggregator);
1000
1001         passes.push_pass(box mir::transform::add_call_guards::AddCallGuards);
1002         passes.push_pass(box mir::transform::dump_mir::Marker("PreTrans"));
1003
1004         passes.run_passes(tcx, &mut mir_map);
1005     });
1006
1007     let translation =
1008         time(time_passes,
1009              "translation",
1010              move || trans::trans_crate(tcx, &mir_map, analysis));
1011
1012     time(time_passes,
1013          "assert dep graph",
1014          move || rustc_incremental::assert_dep_graph(tcx));
1015
1016     time(time_passes,
1017          "serialize dep graph",
1018          move || rustc_incremental::save_dep_graph(tcx));
1019
1020     translation
1021 }
1022
1023 /// Run LLVM itself, producing a bitcode file, assembly file or object file
1024 /// as a side effect.
1025 pub fn phase_5_run_llvm_passes(sess: &Session,
1026                                crate_name: &str,
1027                                trans: &trans::CrateTranslation,
1028                                outputs: &OutputFilenames) -> CompileResult {
1029     if sess.opts.cg.no_integrated_as {
1030         let output_types = OutputTypes::new(&[(OutputType::Assembly, None)]);
1031         time(sess.time_passes(),
1032              "LLVM passes",
1033              || write::run_passes(sess, trans, &output_types, outputs));
1034
1035         write::run_assembler(sess, outputs);
1036
1037         // Remove assembly source, unless --save-temps was specified
1038         if !sess.opts.cg.save_temps {
1039             fs::remove_file(&outputs.temp_path(OutputType::Assembly, None)).unwrap();
1040         }
1041     } else {
1042         time(sess.time_passes(),
1043              "LLVM passes",
1044              || write::run_passes(sess, trans, &sess.opts.output_types, outputs));
1045     }
1046
1047     time(sess.time_passes(),
1048          "serialize work products",
1049          move || rustc_incremental::save_work_products(sess, crate_name));
1050
1051     if sess.err_count() > 0 {
1052         Err(sess.err_count())
1053     } else {
1054         Ok(())
1055     }
1056 }
1057
1058 /// Run the linker on any artifacts that resulted from the LLVM run.
1059 /// This should produce either a finished executable or library.
1060 pub fn phase_6_link_output(sess: &Session,
1061                            trans: &trans::CrateTranslation,
1062                            outputs: &OutputFilenames) {
1063     time(sess.time_passes(),
1064          "linking",
1065          || link::link_binary(sess, trans, outputs, &trans.link.crate_name));
1066 }
1067
1068 fn escape_dep_filename(filename: &str) -> String {
1069     // Apparently clang and gcc *only* escape spaces:
1070     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
1071     filename.replace(" ", "\\ ")
1072 }
1073
1074 fn write_out_deps(sess: &Session, outputs: &OutputFilenames, crate_name: &str) {
1075     let mut out_filenames = Vec::new();
1076     for output_type in sess.opts.output_types.keys() {
1077         let file = outputs.path(*output_type);
1078         match *output_type {
1079             OutputType::Exe => {
1080                 for output in sess.crate_types.borrow().iter() {
1081                     let p = link::filename_for_input(sess, *output, crate_name, outputs);
1082                     out_filenames.push(p);
1083                 }
1084             }
1085             _ => {
1086                 out_filenames.push(file);
1087             }
1088         }
1089     }
1090
1091     // Write out dependency rules to the dep-info file if requested
1092     if !sess.opts.output_types.contains_key(&OutputType::DepInfo) {
1093         return;
1094     }
1095     let deps_filename = outputs.path(OutputType::DepInfo);
1096
1097     let result =
1098         (|| -> io::Result<()> {
1099             // Build a list of files used to compile the output and
1100             // write Makefile-compatible dependency rules
1101             let files: Vec<String> = sess.codemap()
1102                                          .files
1103                                          .borrow()
1104                                          .iter()
1105                                          .filter(|fmap| fmap.is_real_file())
1106                                          .filter(|fmap| !fmap.is_imported())
1107                                          .map(|fmap| escape_dep_filename(&fmap.name))
1108                                          .collect();
1109             let mut file = fs::File::create(&deps_filename)?;
1110             for path in &out_filenames {
1111                 write!(file, "{}: {}\n\n", path.display(), files.join(" "))?;
1112             }
1113
1114             // Emit a fake target for each input file to the compilation. This
1115             // prevents `make` from spitting out an error if a file is later
1116             // deleted. For more info see #28735
1117             for path in files {
1118                 writeln!(file, "{}:", path)?;
1119             }
1120             Ok(())
1121         })();
1122
1123     match result {
1124         Ok(()) => {}
1125         Err(e) => {
1126             sess.fatal(&format!("error writing dependencies to `{}`: {}",
1127                                 deps_filename.display(),
1128                                 e));
1129         }
1130     }
1131 }
1132
1133 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
1134     // Unconditionally collect crate types from attributes to make them used
1135     let attr_types: Vec<config::CrateType> =
1136         attrs.iter()
1137              .filter_map(|a| {
1138                  if a.check_name("crate_type") {
1139                      match a.value_str() {
1140                          Some(ref n) if *n == "rlib" => {
1141                              Some(config::CrateTypeRlib)
1142                          }
1143                          Some(ref n) if *n == "dylib" => {
1144                              Some(config::CrateTypeDylib)
1145                          }
1146                          Some(ref n) if *n == "cdylib" => {
1147                              Some(config::CrateTypeCdylib)
1148                          }
1149                          Some(ref n) if *n == "lib" => {
1150                              Some(config::default_lib_output())
1151                          }
1152                          Some(ref n) if *n == "staticlib" => {
1153                              Some(config::CrateTypeStaticlib)
1154                          }
1155                          Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
1156                          Some(_) => {
1157                              session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
1158                                               ast::CRATE_NODE_ID,
1159                                               a.span,
1160                                               "invalid `crate_type` value".to_string());
1161                              None
1162                          }
1163                          _ => {
1164                              session.struct_span_err(a.span, "`crate_type` requires a value")
1165                                  .note("for example: `#![crate_type=\"lib\"]`")
1166                                  .emit();
1167                              None
1168                          }
1169                      }
1170                  } else {
1171                      None
1172                  }
1173              })
1174              .collect();
1175
1176     // If we're generating a test executable, then ignore all other output
1177     // styles at all other locations
1178     if session.opts.test {
1179         return vec![config::CrateTypeExecutable];
1180     }
1181
1182     // Only check command line flags if present. If no types are specified by
1183     // command line, then reuse the empty `base` Vec to hold the types that
1184     // will be found in crate attributes.
1185     let mut base = session.opts.crate_types.clone();
1186     if base.is_empty() {
1187         base.extend(attr_types);
1188         if base.is_empty() {
1189             base.push(link::default_output_for_target(session));
1190         }
1191         base.sort();
1192         base.dedup();
1193     }
1194
1195     base.into_iter()
1196         .filter(|crate_type| {
1197             let res = !link::invalid_output_for_target(session, *crate_type);
1198
1199             if !res {
1200                 session.warn(&format!("dropping unsupported crate type `{}` for target `{}`",
1201                                       *crate_type,
1202                                       session.opts.target_triple));
1203             }
1204
1205             res
1206         })
1207         .collect()
1208 }
1209
1210 pub fn compute_crate_disambiguator(session: &Session) -> String {
1211     let mut hasher = Sha256::new();
1212
1213     let mut metadata = session.opts.cg.metadata.clone();
1214     // We don't want the crate_disambiguator to dependent on the order
1215     // -C metadata arguments, so sort them:
1216     metadata.sort();
1217     // Every distinct -C metadata value is only incorporated once:
1218     metadata.dedup();
1219
1220     hasher.input_str("metadata");
1221     for s in &metadata {
1222         // Also incorporate the length of a metadata string, so that we generate
1223         // different values for `-Cmetadata=ab -Cmetadata=c` and
1224         // `-Cmetadata=a -Cmetadata=bc`
1225         hasher.input_str(&format!("{}", s.len())[..]);
1226         hasher.input_str(&s[..]);
1227     }
1228
1229     let mut hash = hasher.result_str();
1230
1231     // If this is an executable, add a special suffix, so that we don't get
1232     // symbol conflicts when linking against a library of the same name.
1233     if session.crate_types.borrow().contains(&config::CrateTypeExecutable) {
1234        hash.push_str("-exe");
1235     }
1236
1237     hash
1238 }
1239
1240 pub fn build_output_filenames(input: &Input,
1241                               odir: &Option<PathBuf>,
1242                               ofile: &Option<PathBuf>,
1243                               attrs: &[ast::Attribute],
1244                               sess: &Session)
1245                               -> OutputFilenames {
1246     match *ofile {
1247         None => {
1248             // "-" as input file will cause the parser to read from stdin so we
1249             // have to make up a name
1250             // We want to toss everything after the final '.'
1251             let dirpath = match *odir {
1252                 Some(ref d) => d.clone(),
1253                 None => PathBuf::new(),
1254             };
1255
1256             // If a crate name is present, we use it as the link name
1257             let stem = sess.opts
1258                            .crate_name
1259                            .clone()
1260                            .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
1261                            .unwrap_or(input.filestem());
1262
1263             OutputFilenames {
1264                 out_directory: dirpath,
1265                 out_filestem: stem,
1266                 single_output_file: None,
1267                 extra: sess.opts.cg.extra_filename.clone(),
1268                 outputs: sess.opts.output_types.clone(),
1269             }
1270         }
1271
1272         Some(ref out_file) => {
1273             let unnamed_output_types = sess.opts
1274                                            .output_types
1275                                            .values()
1276                                            .filter(|a| a.is_none())
1277                                            .count();
1278             let ofile = if unnamed_output_types > 1 {
1279                 sess.warn("ignoring specified output filename because multiple outputs were \
1280                            requested");
1281                 None
1282             } else {
1283                 Some(out_file.clone())
1284             };
1285             if *odir != None {
1286                 sess.warn("ignoring --out-dir flag due to -o flag.");
1287             }
1288
1289             let cur_dir = Path::new("");
1290
1291             OutputFilenames {
1292                 out_directory: out_file.parent().unwrap_or(cur_dir).to_path_buf(),
1293                 out_filestem: out_file.file_stem()
1294                                       .unwrap_or(OsStr::new(""))
1295                                       .to_str()
1296                                       .unwrap()
1297                                       .to_string(),
1298                 single_output_file: ofile,
1299                 extra: sess.opts.cg.extra_filename.clone(),
1300                 outputs: sess.opts.output_types.clone(),
1301             }
1302         }
1303     }
1304 }
1305
1306 // For use by the `rusti` project (https://github.com/murarth/rusti).
1307 pub fn reset_thread_local_state() {
1308     // These may be left in an incoherent state after a previous compile.
1309     syntax::ext::hygiene::reset_hygiene_data();
1310     // `clear_ident_interner` can be used to free memory, but it does not restore the initial state.
1311     token::reset_ident_interner();
1312 }