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::dep_graph::DepGraph;
  12 use rustc::hir::{self, map as hir_map};
  13 use rustc::hir::lowering::lower_crate;
  14 use rustc::ich::Fingerprint;
  15 use rustc_data_structures::stable_hasher::StableHasher;
  16 use rustc_mir as mir;
  17 use rustc::session::{Session, CompileResult, CrateDisambiguator};
  18 use rustc::session::CompileIncomplete;
  19 use rustc::session::config::{self, Input, OutputFilenames, OutputType};
  20 use rustc::session::search_paths::PathKind;
  21 use rustc::lint;
  22 use rustc::middle::{self, stability, reachable, resolve_lifetime};
  23 use rustc::middle::cstore::CrateStore;
  24 use rustc::middle::privacy::AccessLevels;
  25 use rustc::ty::{self, TyCtxt, Resolutions, AllArenas};
  26 use rustc::traits;
  27 use rustc::util::common::{ErrorReported, time};
  28 use rustc_allocator as allocator;
  29 use rustc_borrowck as borrowck;
  30 use rustc_incremental;
  31 use rustc_resolve::{MakeGlobMap, Resolver};
  32 use rustc_metadata::creader::CrateLoader;
  33 use rustc_metadata::cstore::{self, CStore};
  34 use rustc_trans as trans;
  35 use rustc_trans_utils::trans_crate::TransCrate;
  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::{self, ast_validation, no_asm, loops, consts, static_recursion, hir_stats};
  41 use rustc_const_eval::{self, check_match};
  42 use super::Compilation;
  43 use ::DefaultTransCrate;
  44
  45 use serialize::json;
  46
  47 use std::any::Any;
  48 use std::env;
  49 use std::ffi::{OsString, OsStr};
  50 use std::fs;
  51 use std::io::{self, Write};
  52 use std::iter;
  53 use std::path::{Path, PathBuf};
  54 use std::rc::Rc;
  55 use std::sync::mpsc;
  56 use syntax::{ast, diagnostics, visit};
  57 use syntax::attr;
  58 use syntax::ext::base::ExtCtxt;
  59 use syntax::fold::Folder;
  60 use syntax::parse::{self, PResult};
  61 use syntax::util::node_count::NodeCounter;
  62 use syntax_pos::FileName;
  63 use syntax;
  64 use syntax_ext;
  65
  66 use derive_registrar;
  67 use pretty::ReplaceBodyWithLoop;
  68
  69 use profile;
  70
  71 pub fn compile_input(sess: &Session,
  72                      cstore: &CStore,
  73                      input_path: &Option<PathBuf>,
  74                      input: &Input,
  75                      outdir: &Option<PathBuf>,
  76                      output: &Option<PathBuf>,
  77                      addl_plugins: Option<Vec<String>>,
  78                      control: &CompileController) -> CompileResult {
  79     use rustc::session::config::CrateType;
  80
  81     macro_rules! controller_entry_point {
  82         ($point: ident, $tsess: expr, $make_state: expr, $phase_result: expr) => {{
  83             let state = &mut $make_state;
  84             let phase_result: &CompileResult = &$phase_result;
  85             if phase_result.is_ok() || control.$point.run_callback_on_error {
  86                 (control.$point.callback)(state);
  87             }
  88
  89             if control.$point.stop == Compilation::Stop {
  90                 // FIXME: shouldn't this return Err(CompileIncomplete::Stopped)
  91                 // if there are no errors?
  92                 return $tsess.compile_status();
  93             }
  94         }}
  95     }
  96
  97     if cfg!(not(feature="llvm")) {
  98         for cty in sess.opts.crate_types.iter() {
  99             match *cty {
 100                 CrateType::CrateTypeRlib | CrateType::CrateTypeDylib |
 101                 CrateType::CrateTypeExecutable => {},
 102                 _ => {
 103                     sess.parse_sess.span_diagnostic.warn(
 104                         &format!("LLVM unsupported, so output type {} is not supported", cty)
 105                     );
 106                 },
 107             }
 108         }
 109
 110         sess.abort_if_errors();
 111     }
 112
 113     if sess.profile_queries() {
 114         profile::begin();
 115     }
 116
 117     // We need nested scopes here, because the intermediate results can keep
 118     // large chunks of memory alive and we want to free them as soon as
 119     // possible to keep the peak memory usage low
 120     let (outputs, trans, dep_graph) = {
 121         let krate = match phase_1_parse_input(control, sess, input) {
 122             Ok(krate) => krate,
 123             Err(mut parse_error) => {
 124                 parse_error.emit();
 125                 return Err(CompileIncomplete::Errored(ErrorReported));
 126             }
 127         };
 128
 129         let (krate, registry) = {
 130             let mut compile_state = CompileState::state_after_parse(input,
 131                                                                     sess,
 132                                                                     outdir,
 133                                                                     output,
 134                                                                     krate,
 135                                                                     &cstore);
 136             controller_entry_point!(after_parse,
 137                                     sess,
 138                                     compile_state,
 139                                     Ok(()));
 140
 141             (compile_state.krate.unwrap(), compile_state.registry)
 142         };
 143
 144         let outputs = build_output_filenames(input, outdir, output, &krate.attrs, sess);
 145
 146         // Ensure the source file isn't accidentally overwritten during compilation.
 147         match *input_path {
 148             Some(ref input_path) => {
 149                 if outputs.contains_path(input_path) && sess.opts.will_create_output_file() {
 150                     sess.err(&format!(
 151                         "the input file \"{}\" would be overwritten by the generated executable",
 152                         input_path.display()));
 153                     return Err(CompileIncomplete::Stopped);
 154                 }
 155             },
 156             None => {}
 157         }
 158
 159         let crate_name =
 160             ::rustc_trans_utils::link::find_crate_name(Some(sess), &krate.attrs, input);
 161         let ExpansionResult { expanded_crate, defs, analysis, resolutions, mut hir_forest } = {
 162             phase_2_configure_and_expand(
 163                 sess,
 164                 &cstore,
 165                 krate,
 166                 registry,
 167                 &crate_name,
 168                 addl_plugins,
 169                 control.make_glob_map,
 170                 |expanded_crate| {
 171                     let mut state = CompileState::state_after_expand(
 172                         input, sess, outdir, output, &cstore, expanded_crate, &crate_name,
 173                     );
 174                     controller_entry_point!(after_expand, sess, state, Ok(()));
 175                     Ok(())
 176                 }
 177             )?
 178         };
 179
 180         write_out_deps(sess, &outputs, &crate_name);
 181         if sess.opts.output_types.contains_key(&OutputType::DepInfo) &&
 182             sess.opts.output_types.keys().count() == 1 {
 183             return Ok(())
 184         }
 185
 186         let arenas = AllArenas::new();
 187
 188         // Construct the HIR map
 189         let hir_map = time(sess.time_passes(),
 190                            "indexing hir",
 191                            || hir_map::map_crate(sess, cstore, &mut hir_forest, &defs));
 192
 193         {
 194             let _ignore = hir_map.dep_graph.in_ignore();
 195             controller_entry_point!(after_hir_lowering,
 196                                     sess,
 197                                     CompileState::state_after_hir_lowering(input,
 198                                                                   sess,
 199                                                                   outdir,
 200                                                                   output,
 201                                                                   &arenas,
 202                                                                   &cstore,
 203                                                                   &hir_map,
 204                                                                   &analysis,
 205                                                                   &resolutions,
 206                                                                   &expanded_crate,
 207                                                                   &hir_map.krate(),
 208                                                                   &outputs,
 209                                                                   &crate_name),
 210                                     Ok(()));
 211         }
 212
 213         time(sess.time_passes(), "attribute checking", || {
 214             hir::check_attr::check_crate(sess, &expanded_crate);
 215         });
 216
 217         let opt_crate = if control.keep_ast {
 218             Some(&expanded_crate)
 219         } else {
 220             drop(expanded_crate);
 221             None
 222         };
 223
 224         phase_3_run_analysis_passes(control,
 225                                     sess,
 226                                     cstore,
 227                                     hir_map,
 228                                     analysis,
 229                                     resolutions,
 230                                     &arenas,
 231                                     &crate_name,
 232                                     &outputs,
 233                                     |tcx, analysis, rx, result| {
 234             {
 235                 // Eventually, we will want to track plugins.
 236                 let _ignore = tcx.dep_graph.in_ignore();
 237
 238                 let mut state = CompileState::state_after_analysis(input,
 239                                                                    sess,
 240                                                                    outdir,
 241                                                                    output,
 242                                                                    opt_crate,
 243                                                                    tcx.hir.krate(),
 244                                                                    &analysis,
 245                                                                    tcx,
 246                                                                    &crate_name);
 247                 (control.after_analysis.callback)(&mut state);
 248
 249                 if control.after_analysis.stop == Compilation::Stop {
 250                     return result.and_then(|_| Err(CompileIncomplete::Stopped));
 251                 }
 252             }
 253
 254             result?;
 255
 256             if log_enabled!(::log::Level::Info) {
 257                 println!("Pre-trans");
 258                 tcx.print_debug_stats();
 259             }
 260
 261             let trans = phase_4_translate_to_llvm::<DefaultTransCrate>(tcx, rx);
 262
 263             if log_enabled!(::log::Level::Info) {
 264                 println!("Post-trans");
 265                 tcx.print_debug_stats();
 266             }
 267
 268             if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
 269                 if let Err(e) = mir::transform::dump_mir::emit_mir(tcx, &outputs) {
 270                     sess.err(&format!("could not emit MIR: {}", e));
 271                     sess.abort_if_errors();
 272                 }
 273             }
 274
 275             Ok((outputs.clone(), trans, tcx.dep_graph.clone()))
 276         })??
 277     };
 278
 279     if sess.opts.debugging_opts.print_type_sizes {
 280         sess.code_stats.borrow().print_type_sizes();
 281     }
 282
 283     let (phase5_result, trans) =
 284         phase_5_run_llvm_passes::<DefaultTransCrate>(sess, &dep_graph, trans);
 285
 286     controller_entry_point!(after_llvm,
 287                             sess,
 288                             CompileState::state_after_llvm(input, sess, outdir, output, &trans),
 289                             phase5_result);
 290     phase5_result?;
 291
 292     // Run the linker on any artifacts that resulted from the LLVM run.
 293     // This should produce either a finished executable or library.
 294     time(sess.time_passes(), "linking", || {
 295         DefaultTransCrate::link_binary(sess, &trans, &outputs)
 296     });
 297
 298     // Now that we won't touch anything in the incremental compilation directory
 299     // any more, we can finalize it (which involves renaming it)
 300     #[cfg(feature="llvm")]
 301     rustc_incremental::finalize_session_directory(sess, trans.link.crate_hash);
 302
 303     if sess.opts.debugging_opts.perf_stats {
 304         sess.print_perf_stats();
 305     }
 306
 307     controller_entry_point!(
 308         compilation_done,
 309         sess,
 310         CompileState::state_when_compilation_done(input, sess, outdir, output),
 311         Ok(())
 312     );
 313
 314     Ok(())
 315 }
 316
 317 fn keep_hygiene_data(sess: &Session) -> bool {
 318     sess.opts.debugging_opts.keep_hygiene_data
 319 }
 320
 321 pub fn source_name(input: &Input) -> FileName {
 322     match *input {
 323         Input::File(ref ifile) => ifile.clone().into(),
 324         Input::Str { ref name, .. } => name.clone(),
 325     }
 326 }
 327
 328 /// CompileController is used to customize compilation, it allows compilation to
 329 /// be stopped and/or to call arbitrary code at various points in compilation.
 330 /// It also allows for various flags to be set to influence what information gets
 331 /// collected during compilation.
 332 ///
 333 /// This is a somewhat higher level controller than a Session - the Session
 334 /// controls what happens in each phase, whereas the CompileController controls
 335 /// whether a phase is run at all and whether other code (from outside the
 336 /// compiler) is run between phases.
 337 ///
 338 /// Note that if compilation is set to stop and a callback is provided for a
 339 /// given entry point, the callback is called before compilation is stopped.
 340 ///
 341 /// Expect more entry points to be added in the future.
 342 pub struct CompileController<'a> {
 343     pub after_parse: PhaseController<'a>,
 344     pub after_expand: PhaseController<'a>,
 345     pub after_hir_lowering: PhaseController<'a>,
 346     pub after_analysis: PhaseController<'a>,
 347     pub after_llvm: PhaseController<'a>,
 348     pub compilation_done: PhaseController<'a>,
 349
 350     // FIXME we probably want to group the below options together and offer a
 351     // better API, rather than this ad-hoc approach.
 352     pub make_glob_map: MakeGlobMap,
 353     // Whether the compiler should keep the ast beyond parsing.
 354     pub keep_ast: bool,
 355     // -Zcontinue-parse-after-error
 356     pub continue_parse_after_error: bool,
 357
 358     /// Allows overriding default rustc query providers,
 359     /// after `default_provide` has installed them.
 360     pub provide: Box<Fn(&mut ty::maps::Providers) + 'a>,
 361     /// Same as `provide`, but only for non-local crates,
 362     /// applied after `default_provide_extern`.
 363     pub provide_extern: Box<Fn(&mut ty::maps::Providers) + 'a>,
 364 }
 365
 366 impl<'a> CompileController<'a> {
 367     pub fn basic() -> CompileController<'a> {
 368         CompileController {
 369             after_parse: PhaseController::basic(),
 370             after_expand: PhaseController::basic(),
 371             after_hir_lowering: PhaseController::basic(),
 372             after_analysis: PhaseController::basic(),
 373             after_llvm: PhaseController::basic(),
 374             compilation_done: PhaseController::basic(),
 375             make_glob_map: MakeGlobMap::No,
 376             keep_ast: false,
 377             continue_parse_after_error: false,
 378             provide: box |_| {},
 379             provide_extern: box |_| {},
 380         }
 381     }
 382 }
 383
 384 pub struct PhaseController<'a> {
 385     pub stop: Compilation,
 386     // If true then the compiler will try to run the callback even if the phase
 387     // ends with an error. Note that this is not always possible.
 388     pub run_callback_on_error: bool,
 389     pub callback: Box<Fn(&mut CompileState) + 'a>,
 390 }
 391
 392 impl<'a> PhaseController<'a> {
 393     pub fn basic() -> PhaseController<'a> {
 394         PhaseController {
 395             stop: Compilation::Continue,
 396             run_callback_on_error: false,
 397             callback: box |_| {},
 398         }
 399     }
 400 }
 401
 402 /// State that is passed to a callback. What state is available depends on when
 403 /// during compilation the callback is made. See the various constructor methods
 404 /// (`state_*`) in the impl to see which data is provided for any given entry point.
 405 pub struct CompileState<'a, 'tcx: 'a> {
 406     pub input: &'a Input,
 407     pub session: &'tcx Session,
 408     pub krate: Option<ast::Crate>,
 409     pub registry: Option<Registry<'a>>,
 410     pub cstore: Option<&'tcx CStore>,
 411     pub crate_name: Option<&'a str>,
 412     pub output_filenames: Option<&'a OutputFilenames>,
 413     pub out_dir: Option<&'a Path>,
 414     pub out_file: Option<&'a Path>,
 415     pub arenas: Option<&'tcx AllArenas<'tcx>>,
 416     pub expanded_crate: Option<&'a ast::Crate>,
 417     pub hir_crate: Option<&'a hir::Crate>,
 418     pub hir_map: Option<&'a hir_map::Map<'tcx>>,
 419     pub resolutions: Option<&'a Resolutions>,
 420     pub analysis: Option<&'a ty::CrateAnalysis>,
 421     pub tcx: Option<TyCtxt<'a, 'tcx, 'tcx>>,
 422     pub trans: Option<&'a trans::CrateTranslation>,
 423 }
 424
 425 impl<'a, 'tcx> CompileState<'a, 'tcx> {
 426     fn empty(input: &'a Input,
 427              session: &'tcx Session,
 428              out_dir: &'a Option<PathBuf>)
 429              -> Self {
 430         CompileState {
 431             input,
 432             session,
 433             out_dir: out_dir.as_ref().map(|s| &**s),
 434             out_file: None,
 435             arenas: None,
 436             krate: None,
 437             registry: None,
 438             cstore: None,
 439             crate_name: None,
 440             output_filenames: None,
 441             expanded_crate: None,
 442             hir_crate: None,
 443             hir_map: None,
 444             resolutions: None,
 445             analysis: None,
 446             tcx: None,
 447             trans: None,
 448         }
 449     }
 450
 451     fn state_after_parse(input: &'a Input,
 452                          session: &'tcx Session,
 453                          out_dir: &'a Option<PathBuf>,
 454                          out_file: &'a Option<PathBuf>,
 455                          krate: ast::Crate,
 456                          cstore: &'tcx CStore)
 457                          -> Self {
 458         CompileState {
 459             // Initialize the registry before moving `krate`
 460             registry: Some(Registry::new(&session, krate.span)),
 461             krate: Some(krate),
 462             cstore: Some(cstore),
 463             out_file: out_file.as_ref().map(|s| &**s),
 464             ..CompileState::empty(input, session, out_dir)
 465         }
 466     }
 467
 468     fn state_after_expand(input: &'a Input,
 469                           session: &'tcx Session,
 470                           out_dir: &'a Option<PathBuf>,
 471                           out_file: &'a Option<PathBuf>,
 472                           cstore: &'tcx CStore,
 473                           expanded_crate: &'a ast::Crate,
 474                           crate_name: &'a str)
 475                           -> Self {
 476         CompileState {
 477             crate_name: Some(crate_name),
 478             cstore: Some(cstore),
 479             expanded_crate: Some(expanded_crate),
 480             out_file: out_file.as_ref().map(|s| &**s),
 481             ..CompileState::empty(input, session, out_dir)
 482         }
 483     }
 484
 485     fn state_after_hir_lowering(input: &'a Input,
 486                                 session: &'tcx Session,
 487                                 out_dir: &'a Option<PathBuf>,
 488                                 out_file: &'a Option<PathBuf>,
 489                                 arenas: &'tcx AllArenas<'tcx>,
 490                                 cstore: &'tcx CStore,
 491                                 hir_map: &'a hir_map::Map<'tcx>,
 492                                 analysis: &'a ty::CrateAnalysis,
 493                                 resolutions: &'a Resolutions,
 494                                 krate: &'a ast::Crate,
 495                                 hir_crate: &'a hir::Crate,
 496                                 output_filenames: &'a OutputFilenames,
 497                                 crate_name: &'a str)
 498                                 -> Self {
 499         CompileState {
 500             crate_name: Some(crate_name),
 501             arenas: Some(arenas),
 502             cstore: Some(cstore),
 503             hir_map: Some(hir_map),
 504             analysis: Some(analysis),
 505             resolutions: Some(resolutions),
 506             expanded_crate: Some(krate),
 507             hir_crate: Some(hir_crate),
 508             output_filenames: Some(output_filenames),
 509             out_file: out_file.as_ref().map(|s| &**s),
 510             ..CompileState::empty(input, session, out_dir)
 511         }
 512     }
 513
 514     fn state_after_analysis(input: &'a Input,
 515                             session: &'tcx Session,
 516                             out_dir: &'a Option<PathBuf>,
 517                             out_file: &'a Option<PathBuf>,
 518                             krate: Option<&'a ast::Crate>,
 519                             hir_crate: &'a hir::Crate,
 520                             analysis: &'a ty::CrateAnalysis,
 521                             tcx: TyCtxt<'a, 'tcx, 'tcx>,
 522                             crate_name: &'a str)
 523                             -> Self {
 524         CompileState {
 525             analysis: Some(analysis),
 526             tcx: Some(tcx),
 527             expanded_crate: krate,
 528             hir_crate: Some(hir_crate),
 529             crate_name: Some(crate_name),
 530             out_file: out_file.as_ref().map(|s| &**s),
 531             ..CompileState::empty(input, session, out_dir)
 532         }
 533     }
 534
 535     fn state_after_llvm(input: &'a Input,
 536                         session: &'tcx Session,
 537                         out_dir: &'a Option<PathBuf>,
 538                         out_file: &'a Option<PathBuf>,
 539                         trans: &'a trans::CrateTranslation)
 540                         -> Self {
 541         CompileState {
 542             trans: Some(trans),
 543             out_file: out_file.as_ref().map(|s| &**s),
 544             ..CompileState::empty(input, session, out_dir)
 545         }
 546     }
 547
 548     fn state_when_compilation_done(input: &'a Input,
 549                                    session: &'tcx Session,
 550                                    out_dir: &'a Option<PathBuf>,
 551                                    out_file: &'a Option<PathBuf>)
 552                                    -> Self {
 553         CompileState {
 554             out_file: out_file.as_ref().map(|s| &**s),
 555             ..CompileState::empty(input, session, out_dir)
 556         }
 557     }
 558 }
 559
 560 pub fn phase_1_parse_input<'a>(control: &CompileController,
 561                                sess: &'a Session,
 562                                input: &Input)
 563                                -> PResult<'a, ast::Crate> {
 564     sess.diagnostic().set_continue_after_error(control.continue_parse_after_error);
 565
 566     if sess.profile_queries() {
 567         profile::begin();
 568     }
 569
 570     let krate = time(sess.time_passes(), "parsing", || {
 571         match *input {
 572             Input::File(ref file) => {
 573                 parse::parse_crate_from_file(file, &sess.parse_sess)
 574             }
 575             Input::Str { ref input, ref name } => {
 576                 parse::parse_crate_from_source_str(name.clone(),
 577                                                    input.clone(),
 578                                                    &sess.parse_sess)
 579             }
 580         }
 581     })?;
 582
 583     sess.diagnostic().set_continue_after_error(true);
 584
 585     if sess.opts.debugging_opts.ast_json_noexpand {
 586         println!("{}", json::as_json(&krate));
 587     }
 588
 589     if sess.opts.debugging_opts.input_stats {
 590         println!("Lines of code:             {}", sess.codemap().count_lines());
 591         println!("Pre-expansion node count:  {}", count_nodes(&krate));
 592     }
 593
 594     if let Some(ref s) = sess.opts.debugging_opts.show_span {
 595         syntax::show_span::run(sess.diagnostic(), s, &krate);
 596     }
 597
 598     if sess.opts.debugging_opts.hir_stats {
 599         hir_stats::print_ast_stats(&krate, "PRE EXPANSION AST STATS");
 600     }
 601
 602     Ok(krate)
 603 }
 604
 605 fn count_nodes(krate: &ast::Crate) -> usize {
 606     let mut counter = NodeCounter::new();
 607     visit::walk_crate(&mut counter, krate);
 608     counter.count
 609 }
 610
 611 // For continuing compilation after a parsed crate has been
 612 // modified
 613
 614 pub struct ExpansionResult {
 615     pub expanded_crate: ast::Crate,
 616     pub defs: hir_map::Definitions,
 617     pub analysis: ty::CrateAnalysis,
 618     pub resolutions: Resolutions,
 619     pub hir_forest: hir_map::Forest,
 620 }
 621
 622 /// Run the "early phases" of the compiler: initial `cfg` processing,
 623 /// loading compiler plugins (including those from `addl_plugins`),
 624 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 625 /// harness if one is to be provided, injection of a dependency on the
 626 /// standard library and prelude, and name resolution.
 627 ///
 628 /// Returns `None` if we're aborting after handling -W help.
 629 pub fn phase_2_configure_and_expand<F>(sess: &Session,
 630                                        cstore: &CStore,
 631                                        krate: ast::Crate,
 632                                        registry: Option<Registry>,
 633                                        crate_name: &str,
 634                                        addl_plugins: Option<Vec<String>>,
 635                                        make_glob_map: MakeGlobMap,
 636                                        after_expand: F)
 637                                        -> Result<ExpansionResult, CompileIncomplete>
 638     where F: FnOnce(&ast::Crate) -> CompileResult,
 639 {
 640     let time_passes = sess.time_passes();
 641
 642     let (mut krate, features) = syntax::config::features(krate, &sess.parse_sess, sess.opts.test);
 643     // these need to be set "early" so that expansion sees `quote` if enabled.
 644     *sess.features.borrow_mut() = features;
 645
 646     *sess.crate_types.borrow_mut() = collect_crate_types(sess, &krate.attrs);
 647
 648     let disambiguator = compute_crate_disambiguator(sess);
 649     *sess.crate_disambiguator.borrow_mut() = Some(disambiguator);
 650     rustc_incremental::prepare_session_directory(
 651         sess,
 652         &crate_name,
 653         disambiguator,
 654     );
 655
 656     // If necessary, compute the dependency graph (in the background).
 657     let future_dep_graph = if sess.opts.build_dep_graph() {
 658         Some(rustc_incremental::load_dep_graph(sess, time_passes))
 659     } else {
 660         None
 661     };
 662
 663     time(time_passes, "recursion limit", || {
 664         middle::recursion_limit::update_limits(sess, &krate);
 665     });
 666
 667     krate = time(time_passes, "crate injection", || {
 668         let alt_std_name = sess.opts.alt_std_name.clone();
 669         syntax::std_inject::maybe_inject_crates_ref(krate, alt_std_name)
 670     });
 671
 672     let mut addl_plugins = Some(addl_plugins);
 673     let registrars = time(time_passes, "plugin loading", || {
 674         plugin::load::load_plugins(sess,
 675                                    &cstore,
 676                                    &krate,
 677                                    crate_name,
 678                                    addl_plugins.take().unwrap())
 679     });
 680
 681     let mut registry = registry.unwrap_or(Registry::new(sess, krate.span));
 682
 683     time(time_passes, "plugin registration", || {
 684         if sess.features.borrow().rustc_diagnostic_macros {
 685             registry.register_macro("__diagnostic_used",
 686                                     diagnostics::plugin::expand_diagnostic_used);
 687             registry.register_macro("__register_diagnostic",
 688                                     diagnostics::plugin::expand_register_diagnostic);
 689             registry.register_macro("__build_diagnostic_array",
 690                                     diagnostics::plugin::expand_build_diagnostic_array);
 691         }
 692
 693         for registrar in registrars {
 694             registry.args_hidden = Some(registrar.args);
 695             (registrar.fun)(&mut registry);
 696         }
 697     });
 698
 699     let whitelisted_legacy_custom_derives = registry.take_whitelisted_custom_derives();
 700     let Registry { syntax_exts, early_lint_passes, late_lint_passes, lint_groups,
 701                    llvm_passes, attributes, .. } = registry;
 702
 703     sess.track_errors(|| {
 704         let mut ls = sess.lint_store.borrow_mut();
 705         for pass in early_lint_passes {
 706             ls.register_early_pass(Some(sess), true, pass);
 707         }
 708         for pass in late_lint_passes {
 709             ls.register_late_pass(Some(sess), true, pass);
 710         }
 711
 712         for (name, to) in lint_groups {
 713             ls.register_group(Some(sess), true, name, to);
 714         }
 715
 716         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
 717         *sess.plugin_attributes.borrow_mut() = attributes.clone();
 718     })?;
 719
 720     // Lint plugins are registered; now we can process command line flags.
 721     if sess.opts.describe_lints {
 722         super::describe_lints(&sess.lint_store.borrow(), true);
 723         return Err(CompileIncomplete::Stopped);
 724     }
 725
 726     // Currently, we ignore the name resolution data structures for the purposes of dependency
 727     // tracking. Instead we will run name resolution and include its output in the hash of each
 728     // item, much like we do for macro expansion. In other words, the hash reflects not just
 729     // its contents but the results of name resolution on those contents. Hopefully we'll push
 730     // this back at some point.
 731     let mut crate_loader = CrateLoader::new(sess, &cstore, crate_name);
 732     let resolver_arenas = Resolver::arenas();
 733     let mut resolver = Resolver::new(sess,
 734                                      cstore,
 735                                      &krate,
 736                                      crate_name,
 737                                      make_glob_map,
 738                                      &mut crate_loader,
 739                                      &resolver_arenas);
 740     resolver.whitelisted_legacy_custom_derives = whitelisted_legacy_custom_derives;
 741     syntax_ext::register_builtins(&mut resolver, syntax_exts, sess.features.borrow().quote);
 742
 743     krate = time(time_passes, "expansion", || {
 744         // Windows dlls do not have rpaths, so they don't know how to find their
 745         // dependencies. It's up to us to tell the system where to find all the
 746         // dependent dlls. Note that this uses cfg!(windows) as opposed to
 747         // targ_cfg because syntax extensions are always loaded for the host
 748         // compiler, not for the target.
 749         //
 750         // This is somewhat of an inherently racy operation, however, as
 751         // multiple threads calling this function could possibly continue
 752         // extending PATH far beyond what it should. To solve this for now we
 753         // just don't add any new elements to PATH which are already there
 754         // within PATH. This is basically a targeted fix at #17360 for rustdoc
 755         // which runs rustc in parallel but has been seen (#33844) to cause
 756         // problems with PATH becoming too long.
 757         let mut old_path = OsString::new();
 758         if cfg!(windows) {
 759             old_path = env::var_os("PATH").unwrap_or(old_path);
 760             let mut new_path = sess.host_filesearch(PathKind::All)
 761                                    .get_dylib_search_paths();
 762             for path in env::split_paths(&old_path) {
 763                 if !new_path.contains(&path) {
 764                     new_path.push(path);
 765                 }
 766             }
 767             env::set_var("PATH",
 768                 &env::join_paths(new_path.iter()
 769                                          .filter(|p| env::join_paths(iter::once(p)).is_ok()))
 770                      .unwrap());
 771         }
 772         let features = sess.features.borrow();
 773         let cfg = syntax::ext::expand::ExpansionConfig {
 774             features: Some(&features),
 775             recursion_limit: sess.recursion_limit.get(),
 776             trace_mac: sess.opts.debugging_opts.trace_macros,
 777             should_test: sess.opts.test,
 778             ..syntax::ext::expand::ExpansionConfig::default(crate_name.to_string())
 779         };
 780
 781         let mut ecx = ExtCtxt::new(&sess.parse_sess, cfg, &mut resolver);
 782         let err_count = ecx.parse_sess.span_diagnostic.err_count();
 783
 784         let krate = ecx.monotonic_expander().expand_crate(krate);
 785
 786         ecx.check_unused_macros();
 787
 788         let mut missing_fragment_specifiers: Vec<_> =
 789             ecx.parse_sess.missing_fragment_specifiers.borrow().iter().cloned().collect();
 790         missing_fragment_specifiers.sort();
 791         for span in missing_fragment_specifiers {
 792             let lint = lint::builtin::MISSING_FRAGMENT_SPECIFIER;
 793             let msg = "missing fragment specifier";
 794             sess.buffer_lint(lint, ast::CRATE_NODE_ID, span, msg);
 795         }
 796         if ecx.parse_sess.span_diagnostic.err_count() - ecx.resolve_err_count > err_count {
 797             ecx.parse_sess.span_diagnostic.abort_if_errors();
 798         }
 799         if cfg!(windows) {
 800             env::set_var("PATH", &old_path);
 801         }
 802         krate
 803     });
 804
 805     krate = time(time_passes, "maybe building test harness", || {
 806         syntax::test::modify_for_testing(&sess.parse_sess,
 807                                          &mut resolver,
 808                                          sess.opts.test,
 809                                          krate,
 810                                          sess.diagnostic())
 811     });
 812
 813     // If we're actually rustdoc then there's no need to actually compile
 814     // anything, so switch everything to just looping
 815     if sess.opts.actually_rustdoc {
 816         krate = ReplaceBodyWithLoop::new(sess).fold_crate(krate);
 817     }
 818
 819     // If we're in rustdoc we're always compiling as an rlib, but that'll trip a
 820     // bunch of checks in the `modify` function below. For now just skip this
 821     // step entirely if we're rustdoc as it's not too useful anyway.
 822     if !sess.opts.actually_rustdoc {
 823         krate = time(time_passes, "maybe creating a macro crate", || {
 824             let crate_types = sess.crate_types.borrow();
 825             let num_crate_types = crate_types.len();
 826             let is_proc_macro_crate = crate_types.contains(&config::CrateTypeProcMacro);
 827             let is_test_crate = sess.opts.test;
 828             syntax_ext::proc_macro_registrar::modify(&sess.parse_sess,
 829                                                      &mut resolver,
 830                                                      krate,
 831                                                      is_proc_macro_crate,
 832                                                      is_test_crate,
 833                                                      num_crate_types,
 834                                                      sess.diagnostic())
 835         });
 836     }
 837
 838     krate = time(time_passes, "creating allocators", || {
 839         allocator::expand::modify(&sess.parse_sess,
 840                                   &mut resolver,
 841                                   krate,
 842                                   sess.diagnostic())
 843     });
 844
 845     after_expand(&krate)?;
 846
 847     if sess.opts.debugging_opts.input_stats {
 848         println!("Post-expansion node count: {}", count_nodes(&krate));
 849     }
 850
 851     if sess.opts.debugging_opts.hir_stats {
 852         hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS");
 853     }
 854
 855     if sess.opts.debugging_opts.ast_json {
 856         println!("{}", json::as_json(&krate));
 857     }
 858
 859     time(time_passes,
 860          "checking for inline asm in case the target doesn't support it",
 861          || no_asm::check_crate(sess, &krate));
 862
 863     time(time_passes,
 864          "AST validation",
 865          || ast_validation::check_crate(sess, &krate));
 866
 867     time(time_passes, "name resolution", || -> CompileResult {
 868         resolver.resolve_crate(&krate);
 869         Ok(())
 870     })?;
 871
 872     if resolver.found_unresolved_macro {
 873         sess.parse_sess.span_diagnostic.abort_if_errors();
 874     }
 875
 876     // Needs to go *after* expansion to be able to check the results of macro expansion.
 877     time(time_passes, "complete gated feature checking", || {
 878         sess.track_errors(|| {
 879             syntax::feature_gate::check_crate(&krate,
 880                                               &sess.parse_sess,
 881                                               &sess.features.borrow(),
 882                                               &attributes,
 883                                               sess.opts.unstable_features);
 884         })
 885     })?;
 886
 887     // Lower ast -> hir.
 888     // First, we need to collect the dep_graph.
 889     let dep_graph = match future_dep_graph {
 890         None => DepGraph::new_disabled(),
 891         Some(future) => {
 892             let prev_graph = future
 893                 .open()
 894                 .expect("Could not join with background dep_graph thread")
 895                 .open(sess);
 896             DepGraph::new(prev_graph)
 897         }
 898     };
 899     let hir_forest = time(time_passes, "lowering ast -> hir", || {
 900         let hir_crate = lower_crate(sess, cstore, &dep_graph, &krate, &mut resolver);
 901
 902         if sess.opts.debugging_opts.hir_stats {
 903             hir_stats::print_hir_stats(&hir_crate);
 904         }
 905
 906         hir_map::Forest::new(hir_crate, &dep_graph)
 907     });
 908
 909     time(time_passes,
 910          "early lint checks",
 911          || lint::check_ast_crate(sess, &krate));
 912
 913     // Discard hygiene data, which isn't required after lowering to HIR.
 914     if !keep_hygiene_data(sess) {
 915         syntax::ext::hygiene::clear_markings();
 916     }
 917
 918     Ok(ExpansionResult {
 919         expanded_crate: krate,
 920         defs: resolver.definitions,
 921         analysis: ty::CrateAnalysis {
 922             access_levels: Rc::new(AccessLevels::default()),
 923             name: crate_name.to_string(),
 924             glob_map: if resolver.make_glob_map { Some(resolver.glob_map) } else { None },
 925         },
 926         resolutions: Resolutions {
 927             freevars: resolver.freevars,
 928             export_map: resolver.export_map,
 929             trait_map: resolver.trait_map,
 930             maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
 931             maybe_unused_extern_crates: resolver.maybe_unused_extern_crates,
 932         },
 933         hir_forest,
 934     })
 935 }
 936
 937 pub fn default_provide(providers: &mut ty::maps::Providers) {
 938     borrowck::provide(providers);
 939     mir::provide(providers);
 940     reachable::provide(providers);
 941     resolve_lifetime::provide(providers);
 942     rustc_privacy::provide(providers);
 943     DefaultTransCrate::provide(providers);
 944     typeck::provide(providers);
 945     ty::provide(providers);
 946     traits::provide(providers);
 947     reachable::provide(providers);
 948     rustc_const_eval::provide(providers);
 949     rustc_passes::provide(providers);
 950     middle::region::provide(providers);
 951     cstore::provide(providers);
 952     lint::provide(providers);
 953 }
 954
 955 pub fn default_provide_extern(providers: &mut ty::maps::Providers) {
 956     cstore::provide_extern(providers);
 957     DefaultTransCrate::provide_extern(providers);
 958 }
 959
 960 /// Run the resolution, typechecking, region checking and other
 961 /// miscellaneous analysis passes on the crate. Return various
 962 /// structures carrying the results of the analysis.
 963 pub fn phase_3_run_analysis_passes<'tcx, F, R>(control: &CompileController,
 964                                                sess: &'tcx Session,
 965                                                cstore: &'tcx CrateStore,
 966                                                hir_map: hir_map::Map<'tcx>,
 967                                                mut analysis: ty::CrateAnalysis,
 968                                                resolutions: Resolutions,
 969                                                arenas: &'tcx AllArenas<'tcx>,
 970                                                name: &str,
 971                                                output_filenames: &OutputFilenames,
 972                                                f: F)
 973                                                -> Result<R, CompileIncomplete>
 974     where F: for<'a> FnOnce(TyCtxt<'a, 'tcx, 'tcx>,
 975                             ty::CrateAnalysis,
 976                             mpsc::Receiver<Box<Any + Send>>,
 977                             CompileResult) -> R
 978 {
 979     macro_rules! try_with_f {
 980         ($e: expr, ($($t:tt)*)) => {
 981             match $e {
 982                 Ok(x) => x,
 983                 Err(x) => {
 984                     f($($t)*, Err(x));
 985                     return Err(x);
 986                 }
 987             }
 988         }
 989     }
 990
 991     let time_passes = sess.time_passes();
 992
 993     let query_result_on_disk_cache = time(time_passes,
 994         "load query result cache",
 995         || rustc_incremental::load_query_result_cache(sess));
 996
 997     time(time_passes,
 998          "looking for entry point",
 999          || middle::entry::find_entry_point(sess, &hir_map));
1000
1001     sess.plugin_registrar_fn.set(time(time_passes, "looking for plugin registrar", || {
1002         plugin::build::find_plugin_registrar(sess.diagnostic(), &hir_map)
1003     }));
1004     sess.derive_registrar_fn.set(derive_registrar::find(&hir_map));
1005
1006     time(time_passes,
1007          "loop checking",
1008          || loops::check_crate(sess, &hir_map));
1009
1010     time(time_passes,
1011               "static item recursion checking",
1012               || static_recursion::check_crate(sess, &hir_map))?;
1013
1014     let mut local_providers = ty::maps::Providers::default();
1015     default_provide(&mut local_providers);
1016     (control.provide)(&mut local_providers);
1017
1018     let mut extern_providers = local_providers;
1019     default_provide_extern(&mut extern_providers);
1020     (control.provide_extern)(&mut extern_providers);
1021
1022     let (tx, rx) = mpsc::channel();
1023
1024     TyCtxt::create_and_enter(sess,
1025                              cstore,
1026                              local_providers,
1027                              extern_providers,
1028                              arenas,
1029                              resolutions,
1030                              hir_map,
1031                              query_result_on_disk_cache,
1032                              name,
1033                              tx,
1034                              output_filenames,
1035                              |tcx| {
1036         // Do some initialization of the DepGraph that can only be done with the
1037         // tcx available.
1038         rustc_incremental::dep_graph_tcx_init(tcx);
1039
1040         time(time_passes,
1041              "stability checking",
1042              || stability::check_unstable_api_usage(tcx));
1043
1044         // passes are timed inside typeck
1045         try_with_f!(typeck::check_crate(tcx), (tcx, analysis, rx));
1046
1047         time(time_passes,
1048              "const checking",
1049              || consts::check_crate(tcx));
1050
1051         analysis.access_levels =
1052             time(time_passes, "privacy checking", || rustc_privacy::check_crate(tcx));
1053
1054         time(time_passes,
1055              "intrinsic checking",
1056              || middle::intrinsicck::check_crate(tcx));
1057
1058         time(time_passes,
1059              "match checking",
1060              || check_match::check_crate(tcx));
1061
1062         // this must run before MIR dump, because
1063         // "not all control paths return a value" is reported here.
1064         //
1065         // maybe move the check to a MIR pass?
1066         time(time_passes,
1067              "liveness checking",
1068              || middle::liveness::check_crate(tcx));
1069
1070         time(time_passes,
1071              "borrow checking",
1072              || borrowck::check_crate(tcx));
1073
1074         time(time_passes,
1075              "MIR borrow checking",
1076              || for def_id in tcx.body_owners() { tcx.mir_borrowck(def_id); });
1077
1078         time(time_passes,
1079              "MIR effect checking",
1080              || for def_id in tcx.body_owners() {
1081                  mir::transform::check_unsafety::check_unsafety(tcx, def_id)
1082              });
1083         // Avoid overwhelming user with errors if type checking failed.
1084         // I'm not sure how helpful this is, to be honest, but it avoids
1085         // a
1086         // lot of annoying errors in the compile-fail tests (basically,
1087         // lint warnings and so on -- kindck used to do this abort, but
1088         // kindck is gone now). -nmatsakis
1089         if sess.err_count() > 0 {
1090             return Ok(f(tcx, analysis, rx, sess.compile_status()));
1091         }
1092
1093         time(time_passes, "death checking", || middle::dead::check_crate(tcx));
1094
1095         time(time_passes, "unused lib feature checking", || {
1096             stability::check_unused_or_stable_features(tcx)
1097         });
1098
1099         time(time_passes, "lint checking", || lint::check_crate(tcx));
1100
1101         return Ok(f(tcx, analysis, rx, tcx.sess.compile_status()));
1102     })
1103 }
1104
1105 /// Run the translation phase to LLVM, after which the AST and analysis can
1106 /// be discarded.
1107 pub fn phase_4_translate_to_llvm<'a, 'tcx, Trans: TransCrate>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1108                                            rx: mpsc::Receiver<Box<Any + Send>>)
1109                                            -> <Trans as TransCrate>::OngoingCrateTranslation {
1110     let time_passes = tcx.sess.time_passes();
1111
1112     time(time_passes,
1113          "resolving dependency formats",
1114          || ::rustc::middle::dependency_format::calculate(tcx));
1115
1116     let translation =
1117         time(time_passes, "translation", move || {
1118             Trans::trans_crate(tcx, rx)
1119         });
1120     if tcx.sess.profile_queries() {
1121         profile::dump("profile_queries".to_string())
1122     }
1123
1124     translation
1125 }
1126
1127 /// Run LLVM itself, producing a bitcode file, assembly file or object file
1128 /// as a side effect.
1129 pub fn phase_5_run_llvm_passes<Trans: TransCrate>(sess: &Session,
1130                                dep_graph: &DepGraph,
1131                                trans: <Trans as TransCrate>::OngoingCrateTranslation)
1132                                -> (CompileResult, <Trans as TransCrate>::TranslatedCrate) {
1133     let trans = Trans::join_trans(trans, sess, dep_graph);
1134
1135     if sess.opts.debugging_opts.incremental_info {
1136         Trans::dump_incremental_data(&trans);
1137     }
1138
1139     time(sess.time_passes(),
1140          "serialize work products",
1141          move || rustc_incremental::save_work_products(sess, dep_graph));
1142
1143     (sess.compile_status(), trans)
1144 }
1145
1146 fn escape_dep_filename(filename: &FileName) -> String {
1147     // Apparently clang and gcc *only* escape spaces:
1148     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
1149     filename.to_string().replace(" ", "\\ ")
1150 }
1151
1152 fn write_out_deps(sess: &Session, outputs: &OutputFilenames, crate_name: &str) {
1153     let mut out_filenames = Vec::new();
1154     for output_type in sess.opts.output_types.keys() {
1155         let file = outputs.path(*output_type);
1156         match *output_type {
1157             OutputType::Exe => {
1158                 for output in sess.crate_types.borrow().iter() {
1159                     let p = ::rustc_trans_utils::link::filename_for_input(
1160                         sess,
1161                         *output,
1162                         crate_name,
1163                         outputs
1164                     );
1165                     out_filenames.push(p);
1166                 }
1167             }
1168             _ => {
1169                 out_filenames.push(file);
1170             }
1171         }
1172     }
1173
1174     // Write out dependency rules to the dep-info file if requested
1175     if !sess.opts.output_types.contains_key(&OutputType::DepInfo) {
1176         return;
1177     }
1178     let deps_filename = outputs.path(OutputType::DepInfo);
1179
1180     let result =
1181         (|| -> io::Result<()> {
1182             // Build a list of files used to compile the output and
1183             // write Makefile-compatible dependency rules
1184             let files: Vec<String> = sess.codemap()
1185                                          .files()
1186                                          .iter()
1187                                          .filter(|fmap| fmap.is_real_file())
1188                                          .filter(|fmap| !fmap.is_imported())
1189                                          .map(|fmap| escape_dep_filename(&fmap.name))
1190                                          .collect();
1191             let mut file = fs::File::create(&deps_filename)?;
1192             for path in &out_filenames {
1193                 write!(file, "{}: {}\n\n", path.display(), files.join(" "))?;
1194             }
1195
1196             // Emit a fake target for each input file to the compilation. This
1197             // prevents `make` from spitting out an error if a file is later
1198             // deleted. For more info see #28735
1199             for path in files {
1200                 writeln!(file, "{}:", path)?;
1201             }
1202             Ok(())
1203         })();
1204
1205     match result {
1206         Ok(()) => {}
1207         Err(e) => {
1208             sess.fatal(&format!("error writing dependencies to `{}`: {}",
1209                                 deps_filename.display(),
1210                                 e));
1211         }
1212     }
1213 }
1214
1215 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
1216     // Unconditionally collect crate types from attributes to make them used
1217     let attr_types: Vec<config::CrateType> =
1218         attrs.iter()
1219              .filter_map(|a| {
1220                  if a.check_name("crate_type") {
1221                      match a.value_str() {
1222                          Some(ref n) if *n == "rlib" => {
1223                              Some(config::CrateTypeRlib)
1224                          }
1225                          Some(ref n) if *n == "dylib" => {
1226                              Some(config::CrateTypeDylib)
1227                          }
1228                          Some(ref n) if *n == "cdylib" => {
1229                              Some(config::CrateTypeCdylib)
1230                          }
1231                          Some(ref n) if *n == "lib" => {
1232                              Some(config::default_lib_output())
1233                          }
1234                          Some(ref n) if *n == "staticlib" => {
1235                              Some(config::CrateTypeStaticlib)
1236                          }
1237                          Some(ref n) if *n == "proc-macro" => {
1238                              Some(config::CrateTypeProcMacro)
1239                          }
1240                          Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
1241                          Some(_) => {
1242                              session.buffer_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
1243                                                  ast::CRATE_NODE_ID,
1244                                                  a.span,
1245                                                  "invalid `crate_type` value");
1246                              None
1247                          }
1248                          _ => {
1249                              session.struct_span_err(a.span, "`crate_type` requires a value")
1250                                  .note("for example: `#![crate_type=\"lib\"]`")
1251                                  .emit();
1252                              None
1253                          }
1254                      }
1255                  } else {
1256                      None
1257                  }
1258              })
1259              .collect();
1260
1261     // If we're generating a test executable, then ignore all other output
1262     // styles at all other locations
1263     if session.opts.test {
1264         return vec![config::CrateTypeExecutable];
1265     }
1266
1267     // Only check command line flags if present. If no types are specified by
1268     // command line, then reuse the empty `base` Vec to hold the types that
1269     // will be found in crate attributes.
1270     let mut base = session.opts.crate_types.clone();
1271     if base.is_empty() {
1272         base.extend(attr_types);
1273         if base.is_empty() {
1274             base.push(::rustc_trans_utils::link::default_output_for_target(session));
1275         }
1276         base.sort();
1277         base.dedup();
1278     }
1279
1280     base.into_iter()
1281         .filter(|crate_type| {
1282             let res = !::rustc_trans_utils::link::invalid_output_for_target(session, *crate_type);
1283
1284             if !res {
1285                 session.warn(&format!("dropping unsupported crate type `{}` for target `{}`",
1286                                       *crate_type,
1287                                       session.opts.target_triple));
1288             }
1289
1290             res
1291         })
1292         .collect()
1293 }
1294
1295 pub fn compute_crate_disambiguator(session: &Session) -> CrateDisambiguator {
1296     use std::hash::Hasher;
1297
1298     // The crate_disambiguator is a 128 bit hash. The disambiguator is fed
1299     // into various other hashes quite a bit (symbol hashes, incr. comp. hashes,
1300     // debuginfo type IDs, etc), so we don't want it to be too wide. 128 bits
1301     // should still be safe enough to avoid collisions in practice.
1302     let mut hasher = StableHasher::<Fingerprint>::new();
1303
1304     let mut metadata = session.opts.cg.metadata.clone();
1305     // We don't want the crate_disambiguator to dependent on the order
1306     // -C metadata arguments, so sort them:
1307     metadata.sort();
1308     // Every distinct -C metadata value is only incorporated once:
1309     metadata.dedup();
1310
1311     hasher.write(b"metadata");
1312     for s in &metadata {
1313         // Also incorporate the length of a metadata string, so that we generate
1314         // different values for `-Cmetadata=ab -Cmetadata=c` and
1315         // `-Cmetadata=a -Cmetadata=bc`
1316         hasher.write_usize(s.len());
1317         hasher.write(s.as_bytes());
1318     }
1319
1320     // Also incorporate crate type, so that we don't get symbol conflicts when
1321     // linking against a library of the same name, if this is an executable.
1322     let is_exe = session.crate_types.borrow().contains(&config::CrateTypeExecutable);
1323     hasher.write(if is_exe { b"exe" } else { b"lib" });
1324
1325     CrateDisambiguator::from(hasher.finish())
1326
1327 }
1328
1329 pub fn build_output_filenames(input: &Input,
1330                               odir: &Option<PathBuf>,
1331                               ofile: &Option<PathBuf>,
1332                               attrs: &[ast::Attribute],
1333                               sess: &Session)
1334                               -> OutputFilenames {
1335     match *ofile {
1336         None => {
1337             // "-" as input file will cause the parser to read from stdin so we
1338             // have to make up a name
1339             // We want to toss everything after the final '.'
1340             let dirpath = match *odir {
1341                 Some(ref d) => d.clone(),
1342                 None => PathBuf::new(),
1343             };
1344
1345             // If a crate name is present, we use it as the link name
1346             let stem = sess.opts
1347                            .crate_name
1348                            .clone()
1349                            .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
1350                            .unwrap_or(input.filestem());
1351
1352             OutputFilenames {
1353                 out_directory: dirpath,
1354                 out_filestem: stem,
1355                 single_output_file: None,
1356                 extra: sess.opts.cg.extra_filename.clone(),
1357                 outputs: sess.opts.output_types.clone(),
1358             }
1359         }
1360
1361         Some(ref out_file) => {
1362             let unnamed_output_types = sess.opts
1363                                            .output_types
1364                                            .values()
1365                                            .filter(|a| a.is_none())
1366                                            .count();
1367             let ofile = if unnamed_output_types > 1 {
1368                 sess.warn("due to multiple output types requested, the explicitly specified \
1369                            output file name will be adapted for each output type");
1370                 None
1371             } else {
1372                 Some(out_file.clone())
1373             };
1374             if *odir != None {
1375                 sess.warn("ignoring --out-dir flag due to -o flag.");
1376             }
1377
1378             let cur_dir = Path::new("");
1379
1380             OutputFilenames {
1381                 out_directory: out_file.parent().unwrap_or(cur_dir).to_path_buf(),
1382                 out_filestem: out_file.file_stem()
1383                                       .unwrap_or(OsStr::new(""))
1384                                       .to_str()
1385                                       .unwrap()
1386                                       .to_string(),
1387                 single_output_file: ofile,
1388                 extra: sess.opts.cg.extra_filename.clone(),
1389                 outputs: sess.opts.output_types.clone(),
1390             }
1391         }
1392     }
1393 }