src/librustc_driver/driver.rs

   1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use rustc::hir::{self, map as hir_map};
  12 use rustc::hir::lowering::lower_crate;
  13 use rustc::ich::Fingerprint;
  14 use rustc_data_structures::stable_hasher::StableHasher;
  15 use rustc_mir as mir;
  16 use rustc::session::{Session, CompileResult};
  17 use rustc::session::CompileIncomplete;
  18 use rustc::session::config::{self, Input, OutputFilenames, OutputType};
  19 use rustc::session::search_paths::PathKind;
  20 use rustc::lint;
  21 use rustc::middle::{self, dependency_format, stability, reachable};
  22 use rustc::middle::privacy::AccessLevels;
  23 use rustc::mir::transform::{MIR_CONST, MIR_VALIDATED, MIR_OPTIMIZED, Passes};
  24 use rustc::ty::{self, TyCtxt, Resolutions, GlobalArenas};
  25 use rustc::traits;
  26 use rustc::util::common::{ErrorReported, time};
  27 use rustc::util::nodemap::NodeSet;
  28 use rustc_allocator as allocator;
  29 use rustc_borrowck as borrowck;
  30 use rustc_incremental::{self, IncrementalHashesMap};
  31 use rustc_resolve::{MakeGlobMap, Resolver};
  32 use rustc_metadata::creader::CrateLoader;
  33 use rustc_metadata::cstore::{self, CStore};
  34 #[cfg(feature="llvm")]
  35 use rustc_trans::back::{link, write};
  36 #[cfg(feature="llvm")]
  37 use rustc_trans as trans;
  38 use rustc_typeck as typeck;
  39 use rustc_privacy;
  40 use rustc_plugin::registry::Registry;
  41 use rustc_plugin as plugin;
  42 use rustc_passes::{ast_validation, no_asm, loops, consts, static_recursion, hir_stats};
  43 use rustc_const_eval::{self, check_match};
  44 use super::Compilation;
  45
  46 use serialize::json;
  47
  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 syntax::{ast, diagnostics, visit};
  56 use syntax::attr;
  57 use syntax::ext::base::ExtCtxt;
  58 use syntax::parse::{self, PResult};
  59 use syntax::symbol::Symbol;
  60 use syntax::util::node_count::NodeCounter;
  61 use syntax;
  62 use syntax_ext;
  63 use arena::DroplessArena;
  64
  65 use derive_registrar;
  66
  67 pub fn compile_input(sess: &Session,
  68                      cstore: &CStore,
  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                 // FIXME: shouldn't this return Err(CompileIncomplete::Stopped)
  84                 // if there are no errors?
  85                 return $tsess.compile_status();
  86             }
  87         }}
  88     }
  89
  90     // We need nested scopes here, because the intermediate results can keep
  91     // large chunks of memory alive and we want to free them as soon as
  92     // possible to keep the peak memory usage low
  93     let (outputs, trans) = {
  94         let krate = match phase_1_parse_input(control, sess, input) {
  95             Ok(krate) => krate,
  96             Err(mut parse_error) => {
  97                 parse_error.emit();
  98                 return Err(CompileIncomplete::Errored(ErrorReported));
  99             }
 100         };
 101
 102         let (krate, registry) = {
 103             let mut compile_state = CompileState::state_after_parse(input,
 104                                                                     sess,
 105                                                                     outdir,
 106                                                                     output,
 107                                                                     krate,
 108                                                                     &cstore);
 109             controller_entry_point!(after_parse,
 110                                     sess,
 111                                     compile_state,
 112                                     Ok(()));
 113
 114             (compile_state.krate.unwrap(), compile_state.registry)
 115         };
 116
 117         let outputs = build_output_filenames(input, outdir, output, &krate.attrs, sess);
 118         let crate_name =
 119             ::rustc_trans_utils::link::find_crate_name(Some(sess), &krate.attrs, input);
 120         let ExpansionResult { expanded_crate, defs, analysis, resolutions, mut hir_forest } = {
 121             phase_2_configure_and_expand(
 122                 sess, &cstore, krate, registry, &crate_name, addl_plugins, control.make_glob_map,
 123                 |expanded_crate| {
 124                     let mut state = CompileState::state_after_expand(
 125                         input, sess, outdir, output, &cstore, expanded_crate, &crate_name,
 126                     );
 127                     controller_entry_point!(after_expand, sess, state, Ok(()));
 128                     Ok(())
 129                 }
 130             )?
 131         };
 132
 133         write_out_deps(sess, &outputs, &crate_name);
 134         if sess.opts.output_types.contains_key(&OutputType::DepInfo) &&
 135             sess.opts.output_types.keys().count() == 1 {
 136             return Ok(())
 137         }
 138
 139         let arena = DroplessArena::new();
 140         let arenas = GlobalArenas::new();
 141
 142         // Construct the HIR map
 143         let hir_map = time(sess.time_passes(),
 144                            "indexing hir",
 145                            || hir_map::map_crate(&mut hir_forest, defs));
 146
 147         {
 148             let _ignore = hir_map.dep_graph.in_ignore();
 149             controller_entry_point!(after_hir_lowering,
 150                                     sess,
 151                                     CompileState::state_after_hir_lowering(input,
 152                                                                   sess,
 153                                                                   outdir,
 154                                                                   output,
 155                                                                   &arena,
 156                                                                   &arenas,
 157                                                                   &cstore,
 158                                                                   &hir_map,
 159                                                                   &analysis,
 160                                                                   &resolutions,
 161                                                                   &expanded_crate,
 162                                                                   &hir_map.krate(),
 163                                                                   &crate_name),
 164                                     Ok(()));
 165         }
 166
 167         time(sess.time_passes(), "attribute checking", || {
 168             hir::check_attr::check_crate(sess, &expanded_crate);
 169         });
 170
 171         let opt_crate = if control.keep_ast {
 172             Some(&expanded_crate)
 173         } else {
 174             drop(expanded_crate);
 175             None
 176         };
 177
 178         phase_3_run_analysis_passes(sess,
 179                                     hir_map,
 180                                     analysis,
 181                                     resolutions,
 182                                     &arena,
 183                                     &arenas,
 184                                     &crate_name,
 185                                     |tcx, analysis, incremental_hashes_map, result| {
 186             {
 187                 // Eventually, we will want to track plugins.
 188                 let _ignore = tcx.dep_graph.in_ignore();
 189
 190                 let mut state = CompileState::state_after_analysis(input,
 191                                                                    sess,
 192                                                                    outdir,
 193                                                                    output,
 194                                                                    opt_crate,
 195                                                                    tcx.hir.krate(),
 196                                                                    &analysis,
 197                                                                    tcx,
 198                                                                    &crate_name);
 199                 (control.after_analysis.callback)(&mut state);
 200
 201                 if control.after_analysis.stop == Compilation::Stop {
 202                     return result.and_then(|_| Err(CompileIncomplete::Stopped));
 203                 }
 204             }
 205
 206             result?;
 207
 208             if log_enabled!(::log::LogLevel::Info) {
 209                 println!("Pre-trans");
 210                 tcx.print_debug_stats();
 211             }
 212
 213             #[cfg(feature="llvm")]
 214             let trans = phase_4_translate_to_llvm(tcx, analysis, incremental_hashes_map,
 215                                                   &outputs);
 216             #[cfg(not(feature="llvm"))]
 217             let trans = { panic!("LLVM not supported by this rustc."); () };
 218
 219             if log_enabled!(::log::LogLevel::Info) {
 220                 println!("Post-trans");
 221                 tcx.print_debug_stats();
 222             }
 223
 224             if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
 225                 if let Err(e) = mir::transform::dump_mir::emit_mir(tcx, &outputs) {
 226                     sess.err(&format!("could not emit MIR: {}", e));
 227                     sess.abort_if_errors();
 228                 }
 229             }
 230
 231             Ok((outputs, trans))
 232         })??
 233     };
 234
 235     #[cfg(not(feature="llvm"))]
 236     unreachable!();
 237
 238     #[cfg(feature="llvm")]
 239     {
 240         if sess.opts.debugging_opts.print_type_sizes {
 241             sess.code_stats.borrow().print_type_sizes();
 242         }
 243
 244         let (phase5_result, trans) = phase_5_run_llvm_passes(sess, trans);
 245
 246         controller_entry_point!(after_llvm,
 247                                 sess,
 248                                 CompileState::state_after_llvm(input, sess, outdir, output, &trans),
 249                                 phase5_result);
 250         phase5_result?;
 251
 252         phase_6_link_output(sess, &trans, &outputs);
 253
 254         // Now that we won't touch anything in the incremental compilation directory
 255         // any more, we can finalize it (which involves renaming it)
 256         rustc_incremental::finalize_session_directory(sess, trans.link.crate_hash);
 257
 258         if sess.opts.debugging_opts.perf_stats {
 259             sess.print_perf_stats();
 260         }
 261
 262         controller_entry_point!(
 263             compilation_done,
 264             sess,
 265             CompileState::state_when_compilation_done(input, sess, outdir, output),
 266             Ok(())
 267         );
 268
 269         Ok(())
 270     }
 271 }
 272
 273 fn keep_hygiene_data(sess: &Session) -> bool {
 274     sess.opts.debugging_opts.keep_hygiene_data
 275 }
 276
 277
 278 /// The name used for source code that doesn't originate in a file
 279 /// (e.g. source from stdin or a string)
 280 pub fn anon_src() -> String {
 281     "<anon>".to_string()
 282 }
 283
 284 pub fn source_name(input: &Input) -> String {
 285     match *input {
 286         // FIXME (#9639): This needs to handle non-utf8 paths
 287         Input::File(ref ifile) => ifile.to_str().unwrap().to_string(),
 288         Input::Str { ref name, .. } => name.clone(),
 289     }
 290 }
 291
 292 /// CompileController is used to customise compilation, it allows compilation to
 293 /// be stopped and/or to call arbitrary code at various points in compilation.
 294 /// It also allows for various flags to be set to influence what information gets
 295 /// collected during compilation.
 296 ///
 297 /// This is a somewhat higher level controller than a Session - the Session
 298 /// controls what happens in each phase, whereas the CompileController controls
 299 /// whether a phase is run at all and whether other code (from outside the
 300 /// the compiler) is run between phases.
 301 ///
 302 /// Note that if compilation is set to stop and a callback is provided for a
 303 /// given entry point, the callback is called before compilation is stopped.
 304 ///
 305 /// Expect more entry points to be added in the future.
 306 pub struct CompileController<'a> {
 307     pub after_parse: PhaseController<'a>,
 308     pub after_expand: PhaseController<'a>,
 309     pub after_hir_lowering: PhaseController<'a>,
 310     pub after_analysis: PhaseController<'a>,
 311     pub after_llvm: PhaseController<'a>,
 312     pub compilation_done: PhaseController<'a>,
 313
 314     // FIXME we probably want to group the below options together and offer a
 315     // better API, rather than this ad-hoc approach.
 316     pub make_glob_map: MakeGlobMap,
 317     // Whether the compiler should keep the ast beyond parsing.
 318     pub keep_ast: bool,
 319     // -Zcontinue-parse-after-error
 320     pub continue_parse_after_error: bool,
 321 }
 322
 323 impl<'a> CompileController<'a> {
 324     pub fn basic() -> CompileController<'a> {
 325         CompileController {
 326             after_parse: PhaseController::basic(),
 327             after_expand: PhaseController::basic(),
 328             after_hir_lowering: PhaseController::basic(),
 329             after_analysis: PhaseController::basic(),
 330             after_llvm: PhaseController::basic(),
 331             compilation_done: PhaseController::basic(),
 332             make_glob_map: MakeGlobMap::No,
 333             keep_ast: false,
 334             continue_parse_after_error: false,
 335         }
 336     }
 337 }
 338
 339 pub struct PhaseController<'a> {
 340     pub stop: Compilation,
 341     // If true then the compiler will try to run the callback even if the phase
 342     // ends with an error. Note that this is not always possible.
 343     pub run_callback_on_error: bool,
 344     pub callback: Box<Fn(&mut CompileState) + 'a>,
 345 }
 346
 347 impl<'a> PhaseController<'a> {
 348     pub fn basic() -> PhaseController<'a> {
 349         PhaseController {
 350             stop: Compilation::Continue,
 351             run_callback_on_error: false,
 352             callback: box |_| {},
 353         }
 354     }
 355 }
 356
 357 /// State that is passed to a callback. What state is available depends on when
 358 /// during compilation the callback is made. See the various constructor methods
 359 /// (`state_*`) in the impl to see which data is provided for any given entry point.
 360 pub struct CompileState<'a, 'tcx: 'a> {
 361     pub input: &'a Input,
 362     pub session: &'tcx Session,
 363     pub krate: Option<ast::Crate>,
 364     pub registry: Option<Registry<'a>>,
 365     pub cstore: Option<&'a CStore>,
 366     pub crate_name: Option<&'a str>,
 367     pub output_filenames: Option<&'a OutputFilenames>,
 368     pub out_dir: Option<&'a Path>,
 369     pub out_file: Option<&'a Path>,
 370     pub arena: Option<&'tcx DroplessArena>,
 371     pub arenas: Option<&'tcx GlobalArenas<'tcx>>,
 372     pub expanded_crate: Option<&'a ast::Crate>,
 373     pub hir_crate: Option<&'a hir::Crate>,
 374     pub hir_map: Option<&'a hir_map::Map<'tcx>>,
 375     pub resolutions: Option<&'a Resolutions>,
 376     pub analysis: Option<&'a ty::CrateAnalysis>,
 377     pub tcx: Option<TyCtxt<'a, 'tcx, 'tcx>>,
 378     #[cfg(feature="llvm")]
 379     pub trans: Option<&'a trans::CrateTranslation>,
 380 }
 381
 382 impl<'a, 'tcx> CompileState<'a, 'tcx> {
 383     fn empty(input: &'a Input,
 384              session: &'tcx Session,
 385              out_dir: &'a Option<PathBuf>)
 386              -> Self {
 387         CompileState {
 388             input: input,
 389             session: session,
 390             out_dir: out_dir.as_ref().map(|s| &**s),
 391             out_file: None,
 392             arena: None,
 393             arenas: None,
 394             krate: None,
 395             registry: None,
 396             cstore: None,
 397             crate_name: None,
 398             output_filenames: None,
 399             expanded_crate: None,
 400             hir_crate: None,
 401             hir_map: None,
 402             resolutions: None,
 403             analysis: None,
 404             tcx: None,
 405             #[cfg(feature="llvm")]
 406             trans: None,
 407         }
 408     }
 409
 410     fn state_after_parse(input: &'a Input,
 411                          session: &'tcx Session,
 412                          out_dir: &'a Option<PathBuf>,
 413                          out_file: &'a Option<PathBuf>,
 414                          krate: ast::Crate,
 415                          cstore: &'a CStore)
 416                          -> Self {
 417         CompileState {
 418             // Initialize the registry before moving `krate`
 419             registry: Some(Registry::new(&session, krate.span)),
 420             krate: Some(krate),
 421             cstore: Some(cstore),
 422             out_file: out_file.as_ref().map(|s| &**s),
 423             ..CompileState::empty(input, session, out_dir)
 424         }
 425     }
 426
 427     fn state_after_expand(input: &'a Input,
 428                           session: &'tcx Session,
 429                           out_dir: &'a Option<PathBuf>,
 430                           out_file: &'a Option<PathBuf>,
 431                           cstore: &'a CStore,
 432                           expanded_crate: &'a ast::Crate,
 433                           crate_name: &'a str)
 434                           -> Self {
 435         CompileState {
 436             crate_name: Some(crate_name),
 437             cstore: Some(cstore),
 438             expanded_crate: Some(expanded_crate),
 439             out_file: out_file.as_ref().map(|s| &**s),
 440             ..CompileState::empty(input, session, out_dir)
 441         }
 442     }
 443
 444     fn state_after_hir_lowering(input: &'a Input,
 445                                 session: &'tcx Session,
 446                                 out_dir: &'a Option<PathBuf>,
 447                                 out_file: &'a Option<PathBuf>,
 448                                 arena: &'tcx DroplessArena,
 449                                 arenas: &'tcx GlobalArenas<'tcx>,
 450                                 cstore: &'a CStore,
 451                                 hir_map: &'a hir_map::Map<'tcx>,
 452                                 analysis: &'a ty::CrateAnalysis,
 453                                 resolutions: &'a Resolutions,
 454                                 krate: &'a ast::Crate,
 455                                 hir_crate: &'a hir::Crate,
 456                                 crate_name: &'a str)
 457                                 -> Self {
 458         CompileState {
 459             crate_name: Some(crate_name),
 460             arena: Some(arena),
 461             arenas: Some(arenas),
 462             cstore: Some(cstore),
 463             hir_map: Some(hir_map),
 464             analysis: Some(analysis),
 465             resolutions: Some(resolutions),
 466             expanded_crate: Some(krate),
 467             hir_crate: Some(hir_crate),
 468             out_file: out_file.as_ref().map(|s| &**s),
 469             ..CompileState::empty(input, session, out_dir)
 470         }
 471     }
 472
 473     fn state_after_analysis(input: &'a Input,
 474                             session: &'tcx Session,
 475                             out_dir: &'a Option<PathBuf>,
 476                             out_file: &'a Option<PathBuf>,
 477                             krate: Option<&'a ast::Crate>,
 478                             hir_crate: &'a hir::Crate,
 479                             analysis: &'a ty::CrateAnalysis,
 480                             tcx: TyCtxt<'a, 'tcx, 'tcx>,
 481                             crate_name: &'a str)
 482                             -> Self {
 483         CompileState {
 484             analysis: Some(analysis),
 485             tcx: Some(tcx),
 486             expanded_crate: krate,
 487             hir_crate: Some(hir_crate),
 488             crate_name: Some(crate_name),
 489             out_file: out_file.as_ref().map(|s| &**s),
 490             ..CompileState::empty(input, session, out_dir)
 491         }
 492     }
 493
 494     #[cfg(feature="llvm")]
 495     fn state_after_llvm(input: &'a Input,
 496                         session: &'tcx Session,
 497                         out_dir: &'a Option<PathBuf>,
 498                         out_file: &'a Option<PathBuf>,
 499                         trans: &'a trans::CrateTranslation)
 500                         -> Self {
 501         CompileState {
 502             trans: Some(trans),
 503             out_file: out_file.as_ref().map(|s| &**s),
 504             ..CompileState::empty(input, session, out_dir)
 505         }
 506     }
 507
 508     fn state_when_compilation_done(input: &'a Input,
 509                                    session: &'tcx Session,
 510                                    out_dir: &'a Option<PathBuf>,
 511                                    out_file: &'a Option<PathBuf>)
 512                                    -> Self {
 513         CompileState {
 514             out_file: out_file.as_ref().map(|s| &**s),
 515             ..CompileState::empty(input, session, out_dir)
 516         }
 517     }
 518 }
 519
 520 pub fn phase_1_parse_input<'a>(control: &CompileController,
 521                                sess: &'a Session,
 522                                input: &Input)
 523                                -> PResult<'a, ast::Crate> {
 524     sess.diagnostic().set_continue_after_error(control.continue_parse_after_error);
 525
 526     let krate = time(sess.time_passes(), "parsing", || {
 527         match *input {
 528             Input::File(ref file) => {
 529                 parse::parse_crate_from_file(file, &sess.parse_sess)
 530             }
 531             Input::Str { ref input, ref name } => {
 532                 parse::parse_crate_from_source_str(name.clone(), input.clone(), &sess.parse_sess)
 533             }
 534         }
 535     })?;
 536
 537     sess.diagnostic().set_continue_after_error(true);
 538
 539     if sess.opts.debugging_opts.ast_json_noexpand {
 540         println!("{}", json::as_json(&krate));
 541     }
 542
 543     if sess.opts.debugging_opts.input_stats {
 544         println!("Lines of code:             {}", sess.codemap().count_lines());
 545         println!("Pre-expansion node count:  {}", count_nodes(&krate));
 546     }
 547
 548     if let Some(ref s) = sess.opts.debugging_opts.show_span {
 549         syntax::show_span::run(sess.diagnostic(), s, &krate);
 550     }
 551
 552     if sess.opts.debugging_opts.hir_stats {
 553         hir_stats::print_ast_stats(&krate, "PRE EXPANSION AST STATS");
 554     }
 555
 556     Ok(krate)
 557 }
 558
 559 fn count_nodes(krate: &ast::Crate) -> usize {
 560     let mut counter = NodeCounter::new();
 561     visit::walk_crate(&mut counter, krate);
 562     counter.count
 563 }
 564
 565 // For continuing compilation after a parsed crate has been
 566 // modified
 567
 568 pub struct ExpansionResult {
 569     pub expanded_crate: ast::Crate,
 570     pub defs: hir_map::Definitions,
 571     pub analysis: ty::CrateAnalysis,
 572     pub resolutions: Resolutions,
 573     pub hir_forest: hir_map::Forest,
 574 }
 575
 576 /// Run the "early phases" of the compiler: initial `cfg` processing,
 577 /// loading compiler plugins (including those from `addl_plugins`),
 578 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 579 /// harness if one is to be provided, injection of a dependency on the
 580 /// standard library and prelude, and name resolution.
 581 ///
 582 /// Returns `None` if we're aborting after handling -W help.
 583 pub fn phase_2_configure_and_expand<F>(sess: &Session,
 584                                        cstore: &CStore,
 585                                        krate: ast::Crate,
 586                                        registry: Option<Registry>,
 587                                        crate_name: &str,
 588                                        addl_plugins: Option<Vec<String>>,
 589                                        make_glob_map: MakeGlobMap,
 590                                        after_expand: F)
 591                                        -> Result<ExpansionResult, CompileIncomplete>
 592     where F: FnOnce(&ast::Crate) -> CompileResult,
 593 {
 594     let time_passes = sess.time_passes();
 595
 596     let (mut krate, features) = syntax::config::features(krate, &sess.parse_sess, sess.opts.test);
 597     // these need to be set "early" so that expansion sees `quote` if enabled.
 598     *sess.features.borrow_mut() = features;
 599
 600     *sess.crate_types.borrow_mut() = collect_crate_types(sess, &krate.attrs);
 601     *sess.crate_disambiguator.borrow_mut() = Symbol::intern(&compute_crate_disambiguator(sess));
 602
 603     time(time_passes, "recursion limit", || {
 604         middle::recursion_limit::update_limits(sess, &krate);
 605     });
 606
 607     krate = time(time_passes, "crate injection", || {
 608         let alt_std_name = sess.opts.alt_std_name.clone();
 609         syntax::std_inject::maybe_inject_crates_ref(krate, alt_std_name)
 610     });
 611
 612     let mut addl_plugins = Some(addl_plugins);
 613     let registrars = time(time_passes, "plugin loading", || {
 614         plugin::load::load_plugins(sess,
 615                                    &cstore,
 616                                    &krate,
 617                                    crate_name,
 618                                    addl_plugins.take().unwrap())
 619     });
 620
 621     let mut registry = registry.unwrap_or(Registry::new(sess, krate.span));
 622
 623     time(time_passes, "plugin registration", || {
 624         if sess.features.borrow().rustc_diagnostic_macros {
 625             registry.register_macro("__diagnostic_used",
 626                                     diagnostics::plugin::expand_diagnostic_used);
 627             registry.register_macro("__register_diagnostic",
 628                                     diagnostics::plugin::expand_register_diagnostic);
 629             registry.register_macro("__build_diagnostic_array",
 630                                     diagnostics::plugin::expand_build_diagnostic_array);
 631         }
 632
 633         for registrar in registrars {
 634             registry.args_hidden = Some(registrar.args);
 635             (registrar.fun)(&mut registry);
 636         }
 637     });
 638
 639     let whitelisted_legacy_custom_derives = registry.take_whitelisted_custom_derives();
 640     let Registry { syntax_exts, early_lint_passes, late_lint_passes, lint_groups,
 641                    llvm_passes, attributes, .. } = registry;
 642
 643     sess.track_errors(|| {
 644         let mut ls = sess.lint_store.borrow_mut();
 645         for pass in early_lint_passes {
 646             ls.register_early_pass(Some(sess), true, pass);
 647         }
 648         for pass in late_lint_passes {
 649             ls.register_late_pass(Some(sess), true, pass);
 650         }
 651
 652         for (name, to) in lint_groups {
 653             ls.register_group(Some(sess), true, name, to);
 654         }
 655
 656         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
 657         *sess.plugin_attributes.borrow_mut() = attributes.clone();
 658     })?;
 659
 660     // Lint plugins are registered; now we can process command line flags.
 661     if sess.opts.describe_lints {
 662         super::describe_lints(&sess.lint_store.borrow(), true);
 663         return Err(CompileIncomplete::Stopped);
 664     }
 665
 666     // Currently, we ignore the name resolution data structures for the purposes of dependency
 667     // tracking. Instead we will run name resolution and include its output in the hash of each
 668     // item, much like we do for macro expansion. In other words, the hash reflects not just
 669     // its contents but the results of name resolution on those contents. Hopefully we'll push
 670     // this back at some point.
 671     let _ignore = sess.dep_graph.in_ignore();
 672     let mut crate_loader = CrateLoader::new(sess, &cstore, crate_name);
 673     crate_loader.preprocess(&krate);
 674     let resolver_arenas = Resolver::arenas();
 675     let mut resolver = Resolver::new(sess,
 676                                      &krate,
 677                                      crate_name,
 678                                      make_glob_map,
 679                                      &mut crate_loader,
 680                                      &resolver_arenas);
 681     resolver.whitelisted_legacy_custom_derives = whitelisted_legacy_custom_derives;
 682     syntax_ext::register_builtins(&mut resolver, syntax_exts, sess.features.borrow().quote);
 683
 684     krate = time(time_passes, "expansion", || {
 685         // Windows dlls do not have rpaths, so they don't know how to find their
 686         // dependencies. It's up to us to tell the system where to find all the
 687         // dependent dlls. Note that this uses cfg!(windows) as opposed to
 688         // targ_cfg because syntax extensions are always loaded for the host
 689         // compiler, not for the target.
 690         //
 691         // This is somewhat of an inherently racy operation, however, as
 692         // multiple threads calling this function could possibly continue
 693         // extending PATH far beyond what it should. To solve this for now we
 694         // just don't add any new elements to PATH which are already there
 695         // within PATH. This is basically a targeted fix at #17360 for rustdoc
 696         // which runs rustc in parallel but has been seen (#33844) to cause
 697         // problems with PATH becoming too long.
 698         let mut old_path = OsString::new();
 699         if cfg!(windows) {
 700             old_path = env::var_os("PATH").unwrap_or(old_path);
 701             let mut new_path = sess.host_filesearch(PathKind::All)
 702                                    .get_dylib_search_paths();
 703             for path in env::split_paths(&old_path) {
 704                 if !new_path.contains(&path) {
 705                     new_path.push(path);
 706                 }
 707             }
 708             env::set_var("PATH",
 709                 &env::join_paths(new_path.iter()
 710                                          .filter(|p| env::join_paths(iter::once(p)).is_ok()))
 711                      .unwrap());
 712         }
 713         let features = sess.features.borrow();
 714         let cfg = syntax::ext::expand::ExpansionConfig {
 715             features: Some(&features),
 716             recursion_limit: sess.recursion_limit.get(),
 717             trace_mac: sess.opts.debugging_opts.trace_macros,
 718             should_test: sess.opts.test,
 719             ..syntax::ext::expand::ExpansionConfig::default(crate_name.to_string())
 720         };
 721
 722         let mut ecx = ExtCtxt::new(&sess.parse_sess, cfg, &mut resolver);
 723         let err_count = ecx.parse_sess.span_diagnostic.err_count();
 724
 725         let krate = ecx.monotonic_expander().expand_crate(krate);
 726
 727         ecx.check_unused_macros();
 728
 729         let mut missing_fragment_specifiers: Vec<_> =
 730             ecx.parse_sess.missing_fragment_specifiers.borrow().iter().cloned().collect();
 731         missing_fragment_specifiers.sort();
 732         for span in missing_fragment_specifiers {
 733             let lint = lint::builtin::MISSING_FRAGMENT_SPECIFIER;
 734             let msg = "missing fragment specifier";
 735             sess.buffer_lint(lint, ast::CRATE_NODE_ID, span, msg);
 736         }
 737         if ecx.parse_sess.span_diagnostic.err_count() - ecx.resolve_err_count > err_count {
 738             ecx.parse_sess.span_diagnostic.abort_if_errors();
 739         }
 740         if cfg!(windows) {
 741             env::set_var("PATH", &old_path);
 742         }
 743         krate
 744     });
 745
 746     krate = time(time_passes, "maybe building test harness", || {
 747         syntax::test::modify_for_testing(&sess.parse_sess,
 748                                          &mut resolver,
 749                                          sess.opts.test,
 750                                          krate,
 751                                          sess.diagnostic())
 752     });
 753
 754     // If we're in rustdoc we're always compiling as an rlib, but that'll trip a
 755     // bunch of checks in the `modify` function below. For now just skip this
 756     // step entirely if we're rustdoc as it's not too useful anyway.
 757     if !sess.opts.actually_rustdoc {
 758         krate = time(time_passes, "maybe creating a macro crate", || {
 759             let crate_types = sess.crate_types.borrow();
 760             let num_crate_types = crate_types.len();
 761             let is_proc_macro_crate = crate_types.contains(&config::CrateTypeProcMacro);
 762             let is_test_crate = sess.opts.test;
 763             syntax_ext::proc_macro_registrar::modify(&sess.parse_sess,
 764                                                      &mut resolver,
 765                                                      krate,
 766                                                      is_proc_macro_crate,
 767                                                      is_test_crate,
 768                                                      num_crate_types,
 769                                                      sess.diagnostic())
 770         });
 771     }
 772
 773     krate = time(time_passes, "creating allocators", || {
 774         allocator::expand::modify(&sess.parse_sess,
 775                                   &mut resolver,
 776                                   krate,
 777                                   sess.diagnostic())
 778     });
 779
 780     after_expand(&krate)?;
 781
 782     if sess.opts.debugging_opts.input_stats {
 783         println!("Post-expansion node count: {}", count_nodes(&krate));
 784     }
 785
 786     if sess.opts.debugging_opts.hir_stats {
 787         hir_stats::print_ast_stats(&krate, "POST EXPANSION AST STATS");
 788     }
 789
 790     if sess.opts.debugging_opts.ast_json {
 791         println!("{}", json::as_json(&krate));
 792     }
 793
 794     time(time_passes,
 795          "checking for inline asm in case the target doesn't support it",
 796          || no_asm::check_crate(sess, &krate));
 797
 798     time(time_passes,
 799          "AST validation",
 800          || ast_validation::check_crate(sess, &krate));
 801
 802     time(time_passes, "name resolution", || -> CompileResult {
 803         resolver.resolve_crate(&krate);
 804         Ok(())
 805     })?;
 806
 807     if resolver.found_unresolved_macro {
 808         sess.parse_sess.span_diagnostic.abort_if_errors();
 809     }
 810
 811     // Needs to go *after* expansion to be able to check the results of macro expansion.
 812     time(time_passes, "complete gated feature checking", || {
 813         sess.track_errors(|| {
 814             syntax::feature_gate::check_crate(&krate,
 815                                               &sess.parse_sess,
 816                                               &sess.features.borrow(),
 817                                               &attributes,
 818                                               sess.opts.unstable_features);
 819         })
 820     })?;
 821
 822     time(time_passes,
 823          "early lint checks",
 824          || lint::check_ast_crate(sess, &krate));
 825
 826     // Lower ast -> hir.
 827     let hir_forest = time(time_passes, "lowering ast -> hir", || {
 828         let hir_crate = lower_crate(sess, &krate, &mut resolver);
 829
 830         if sess.opts.debugging_opts.hir_stats {
 831             hir_stats::print_hir_stats(&hir_crate);
 832         }
 833
 834         hir_map::Forest::new(hir_crate, &sess.dep_graph)
 835     });
 836
 837     // Discard hygiene data, which isn't required after lowering to HIR.
 838     if !keep_hygiene_data(sess) {
 839         syntax::ext::hygiene::clear_markings();
 840     }
 841
 842     Ok(ExpansionResult {
 843         expanded_crate: krate,
 844         defs: resolver.definitions,
 845         analysis: ty::CrateAnalysis {
 846             access_levels: Rc::new(AccessLevels::default()),
 847             reachable: Rc::new(NodeSet()),
 848             name: crate_name.to_string(),
 849             glob_map: if resolver.make_glob_map { Some(resolver.glob_map) } else { None },
 850         },
 851         resolutions: Resolutions {
 852             freevars: resolver.freevars,
 853             export_map: resolver.export_map,
 854             trait_map: resolver.trait_map,
 855             maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
 856         },
 857         hir_forest: hir_forest,
 858     })
 859 }
 860
 861 /// Run the resolution, typechecking, region checking and other
 862 /// miscellaneous analysis passes on the crate. Return various
 863 /// structures carrying the results of the analysis.
 864 pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 865                                                hir_map: hir_map::Map<'tcx>,
 866                                                mut analysis: ty::CrateAnalysis,
 867                                                resolutions: Resolutions,
 868                                                arena: &'tcx DroplessArena,
 869                                                arenas: &'tcx GlobalArenas<'tcx>,
 870                                                name: &str,
 871                                                f: F)
 872                                                -> Result<R, CompileIncomplete>
 873     where F: for<'a> FnOnce(TyCtxt<'a, 'tcx, 'tcx>,
 874                             ty::CrateAnalysis,
 875                             IncrementalHashesMap,
 876                             CompileResult) -> R
 877 {
 878     macro_rules! try_with_f {
 879         ($e: expr, ($t: expr, $a: expr, $h: expr)) => {
 880             match $e {
 881                 Ok(x) => x,
 882                 Err(x) => {
 883                     f($t, $a, $h, Err(x));
 884                     return Err(x);
 885                 }
 886             }
 887         }
 888     }
 889
 890     let time_passes = sess.time_passes();
 891
 892     let lang_items = time(time_passes, "language item collection", || {
 893         sess.track_errors(|| {
 894             middle::lang_items::collect_language_items(&sess, &hir_map)
 895         })
 896     })?;
 897
 898     let named_region_map = time(time_passes,
 899                                 "lifetime resolution",
 900                                 || middle::resolve_lifetime::krate(sess, &hir_map))?;
 901
 902     time(time_passes,
 903          "looking for entry point",
 904          || middle::entry::find_entry_point(sess, &hir_map));
 905
 906     sess.plugin_registrar_fn.set(time(time_passes, "looking for plugin registrar", || {
 907         plugin::build::find_plugin_registrar(sess.diagnostic(), &hir_map)
 908     }));
 909     sess.derive_registrar_fn.set(derive_registrar::find(&hir_map));
 910
 911     time(time_passes,
 912          "loop checking",
 913          || loops::check_crate(sess, &hir_map));
 914
 915     time(time_passes,
 916               "static item recursion checking",
 917               || static_recursion::check_crate(sess, &hir_map))?;
 918
 919     let index = stability::Index::new(&sess);
 920
 921     let mut local_providers = ty::maps::Providers::default();
 922     borrowck::provide(&mut local_providers);
 923     mir::provide(&mut local_providers);
 924     reachable::provide(&mut local_providers);
 925     rustc_privacy::provide(&mut local_providers);
 926     #[cfg(feature="llvm")]
 927     trans::provide(&mut local_providers);
 928     typeck::provide(&mut local_providers);
 929     ty::provide(&mut local_providers);
 930     traits::provide(&mut local_providers);
 931     reachable::provide(&mut local_providers);
 932     rustc_const_eval::provide(&mut local_providers);
 933     middle::region::provide(&mut local_providers);
 934     cstore::provide_local(&mut local_providers);
 935     lint::provide(&mut local_providers);
 936
 937     let mut extern_providers = ty::maps::Providers::default();
 938     cstore::provide(&mut extern_providers);
 939     #[cfg(feature="llvm")]
 940     trans::provide(&mut extern_providers);
 941     ty::provide_extern(&mut extern_providers);
 942     traits::provide_extern(&mut extern_providers);
 943     // FIXME(eddyb) get rid of this once we replace const_eval with miri.
 944     rustc_const_eval::provide(&mut extern_providers);
 945
 946     // Setup the MIR passes that we want to run.
 947     let mut passes = Passes::new();
 948     passes.push_hook(mir::transform::dump_mir::DumpMir);
 949
 950     // Remove all `EndRegion` statements that are not involved in borrows.
 951     passes.push_pass(MIR_CONST, mir::transform::clean_end_regions::CleanEndRegions);
 952
 953     // What we need to do constant evaluation.
 954     passes.push_pass(MIR_CONST, mir::transform::simplify::SimplifyCfg::new("initial"));
 955     passes.push_pass(MIR_CONST, mir::transform::type_check::TypeckMir);
 956     passes.push_pass(MIR_CONST, mir::transform::rustc_peek::SanityCheck);
 957
 958     // We compute "constant qualifications" betwen MIR_CONST and MIR_VALIDATED.
 959
 960     // What we need to run borrowck etc.
 961     passes.push_pass(MIR_VALIDATED, mir::transform::qualify_consts::QualifyAndPromoteConstants);
 962     passes.push_pass(MIR_VALIDATED,
 963                      mir::transform::simplify_branches::SimplifyBranches::new("initial"));
 964     passes.push_pass(MIR_VALIDATED, mir::transform::simplify::SimplifyCfg::new("qualify-consts"));
 965     passes.push_pass(MIR_VALIDATED, mir::transform::nll::NLL);
 966
 967     // borrowck runs between MIR_VALIDATED and MIR_OPTIMIZED.
 968
 969     // These next passes must be executed together
 970     passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads);
 971     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::AddCallGuards);
 972     passes.push_pass(MIR_OPTIMIZED, mir::transform::elaborate_drops::ElaborateDrops);
 973     passes.push_pass(MIR_OPTIMIZED, mir::transform::no_landing_pads::NoLandingPads);
 974     passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyCfg::new("elaborate-drops"));
 975     // No lifetime analysis based on borrowing can be done from here on out.
 976
 977     // AddValidation needs to run after ElaborateDrops and before EraseRegions.
 978     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_validation::AddValidation);
 979
 980     // From here on out, regions are gone.
 981     passes.push_pass(MIR_OPTIMIZED, mir::transform::erase_regions::EraseRegions);
 982
 983     // Optimizations begin.
 984     passes.push_pass(MIR_OPTIMIZED, mir::transform::inline::Inline);
 985     passes.push_pass(MIR_OPTIMIZED, mir::transform::instcombine::InstCombine);
 986     passes.push_pass(MIR_OPTIMIZED, mir::transform::deaggregator::Deaggregator);
 987     passes.push_pass(MIR_OPTIMIZED, mir::transform::copy_prop::CopyPropagation);
 988     passes.push_pass(MIR_OPTIMIZED, mir::transform::simplify::SimplifyLocals);
 989     passes.push_pass(MIR_OPTIMIZED, mir::transform::add_call_guards::AddCallGuards);
 990     passes.push_pass(MIR_OPTIMIZED, mir::transform::dump_mir::Marker("PreTrans"));
 991
 992     TyCtxt::create_and_enter(sess,
 993                              local_providers,
 994                              extern_providers,
 995                              Rc::new(passes),
 996                              arenas,
 997                              arena,
 998                              resolutions,
 999                              named_region_map,
1000                              hir_map,
1001                              lang_items,
1002                              index,
1003                              name,
1004                              |tcx| {
1005         let incremental_hashes_map =
1006             time(time_passes,
1007                  "compute_incremental_hashes_map",
1008                  || rustc_incremental::compute_incremental_hashes_map(tcx));
1009
1010         time(time_passes,
1011              "load_dep_graph",
1012              || rustc_incremental::load_dep_graph(tcx, &incremental_hashes_map));
1013
1014         time(time_passes, "stability index", || {
1015             tcx.stability.borrow_mut().build(tcx)
1016         });
1017
1018         time(time_passes,
1019              "stability checking",
1020              || stability::check_unstable_api_usage(tcx));
1021
1022         // passes are timed inside typeck
1023         try_with_f!(typeck::check_crate(tcx), (tcx, analysis, incremental_hashes_map));
1024
1025         time(time_passes,
1026              "const checking",
1027              || consts::check_crate(tcx));
1028
1029         analysis.access_levels =
1030             time(time_passes, "privacy checking", || rustc_privacy::check_crate(tcx));
1031
1032         time(time_passes,
1033              "intrinsic checking",
1034              || middle::intrinsicck::check_crate(tcx));
1035
1036         time(time_passes,
1037              "effect checking",
1038              || middle::effect::check_crate(tcx));
1039
1040         time(time_passes,
1041              "match checking",
1042              || check_match::check_crate(tcx));
1043
1044         // this must run before MIR dump, because
1045         // "not all control paths return a value" is reported here.
1046         //
1047         // maybe move the check to a MIR pass?
1048         time(time_passes,
1049              "liveness checking",
1050              || middle::liveness::check_crate(tcx));
1051
1052         time(time_passes,
1053              "borrow checking",
1054              || borrowck::check_crate(tcx));
1055
1056         // Avoid overwhelming user with errors if type checking failed.
1057         // I'm not sure how helpful this is, to be honest, but it avoids
1058         // a
1059         // lot of annoying errors in the compile-fail tests (basically,
1060         // lint warnings and so on -- kindck used to do this abort, but
1061         // kindck is gone now). -nmatsakis
1062         if sess.err_count() > 0 {
1063             return Ok(f(tcx, analysis, incremental_hashes_map, sess.compile_status()));
1064         }
1065
1066         analysis.reachable =
1067             time(time_passes,
1068                  "reachability checking",
1069                  || reachable::find_reachable(tcx));
1070
1071         time(time_passes, "death checking", || middle::dead::check_crate(tcx));
1072
1073         time(time_passes, "unused lib feature checking", || {
1074             stability::check_unused_or_stable_features(tcx)
1075         });
1076
1077         time(time_passes, "lint checking", || lint::check_crate(tcx));
1078
1079         return Ok(f(tcx, analysis, incremental_hashes_map, tcx.sess.compile_status()));
1080     })
1081 }
1082
1083 /// Run the translation phase to LLVM, after which the AST and analysis can
1084 /// be discarded.
1085 #[cfg(feature="llvm")]
1086 pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1087                                            analysis: ty::CrateAnalysis,
1088                                            incremental_hashes_map: IncrementalHashesMap,
1089                                            output_filenames: &OutputFilenames)
1090                                            -> write::OngoingCrateTranslation {
1091     let time_passes = tcx.sess.time_passes();
1092
1093     time(time_passes,
1094          "resolving dependency formats",
1095          || dependency_format::calculate(tcx));
1096
1097     let translation =
1098         time(time_passes,
1099              "translation",
1100              move || trans::trans_crate(tcx, analysis, incremental_hashes_map, output_filenames));
1101
1102     translation
1103 }
1104
1105 /// Run LLVM itself, producing a bitcode file, assembly file or object file
1106 /// as a side effect.
1107 #[cfg(feature="llvm")]
1108 pub fn phase_5_run_llvm_passes(sess: &Session,
1109                                trans: write::OngoingCrateTranslation)
1110                                -> (CompileResult, trans::CrateTranslation) {
1111     let trans = trans.join(sess);
1112
1113     if sess.opts.debugging_opts.incremental_info {
1114         write::dump_incremental_data(&trans);
1115     }
1116
1117     time(sess.time_passes(),
1118          "serialize work products",
1119          move || rustc_incremental::save_work_products(sess));
1120
1121     (sess.compile_status(), trans)
1122 }
1123
1124 /// Run the linker on any artifacts that resulted from the LLVM run.
1125 /// This should produce either a finished executable or library.
1126 #[cfg(feature="llvm")]
1127 pub fn phase_6_link_output(sess: &Session,
1128                            trans: &trans::CrateTranslation,
1129                            outputs: &OutputFilenames) {
1130     time(sess.time_passes(),
1131          "linking",
1132          || link::link_binary(sess, trans, outputs, &trans.crate_name.as_str()));
1133 }
1134
1135 fn escape_dep_filename(filename: &str) -> String {
1136     // Apparently clang and gcc *only* escape spaces:
1137     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
1138     filename.replace(" ", "\\ ")
1139 }
1140
1141 fn write_out_deps(sess: &Session, outputs: &OutputFilenames, crate_name: &str) {
1142     let mut out_filenames = Vec::new();
1143     for output_type in sess.opts.output_types.keys() {
1144         let file = outputs.path(*output_type);
1145         match *output_type {
1146             OutputType::Exe => {
1147                 for output in sess.crate_types.borrow().iter() {
1148                     let p = ::rustc_trans_utils::link::filename_for_input(sess, *output, crate_name, outputs);
1149                     out_filenames.push(p);
1150                 }
1151             }
1152             _ => {
1153                 out_filenames.push(file);
1154             }
1155         }
1156     }
1157
1158     // Write out dependency rules to the dep-info file if requested
1159     if !sess.opts.output_types.contains_key(&OutputType::DepInfo) {
1160         return;
1161     }
1162     let deps_filename = outputs.path(OutputType::DepInfo);
1163
1164     let result =
1165         (|| -> io::Result<()> {
1166             // Build a list of files used to compile the output and
1167             // write Makefile-compatible dependency rules
1168             let files: Vec<String> = sess.codemap()
1169                                          .files()
1170                                          .iter()
1171                                          .filter(|fmap| fmap.is_real_file())
1172                                          .filter(|fmap| !fmap.is_imported())
1173                                          .map(|fmap| escape_dep_filename(&fmap.name))
1174                                          .collect();
1175             let mut file = fs::File::create(&deps_filename)?;
1176             for path in &out_filenames {
1177                 write!(file, "{}: {}\n\n", path.display(), files.join(" "))?;
1178             }
1179
1180             // Emit a fake target for each input file to the compilation. This
1181             // prevents `make` from spitting out an error if a file is later
1182             // deleted. For more info see #28735
1183             for path in files {
1184                 writeln!(file, "{}:", path)?;
1185             }
1186             Ok(())
1187         })();
1188
1189     match result {
1190         Ok(()) => {}
1191         Err(e) => {
1192             sess.fatal(&format!("error writing dependencies to `{}`: {}",
1193                                 deps_filename.display(),
1194                                 e));
1195         }
1196     }
1197 }
1198
1199 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
1200     // Unconditionally collect crate types from attributes to make them used
1201     let attr_types: Vec<config::CrateType> =
1202         attrs.iter()
1203              .filter_map(|a| {
1204                  if a.check_name("crate_type") {
1205                      match a.value_str() {
1206                          Some(ref n) if *n == "rlib" => {
1207                              Some(config::CrateTypeRlib)
1208                          }
1209                          Some(ref n) if *n == "dylib" => {
1210                              Some(config::CrateTypeDylib)
1211                          }
1212                          Some(ref n) if *n == "cdylib" => {
1213                              Some(config::CrateTypeCdylib)
1214                          }
1215                          Some(ref n) if *n == "lib" => {
1216                              Some(config::default_lib_output())
1217                          }
1218                          Some(ref n) if *n == "staticlib" => {
1219                              Some(config::CrateTypeStaticlib)
1220                          }
1221                          Some(ref n) if *n == "proc-macro" => {
1222                              Some(config::CrateTypeProcMacro)
1223                          }
1224                          Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
1225                          Some(_) => {
1226                              session.buffer_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
1227                                                  ast::CRATE_NODE_ID,
1228                                                  a.span,
1229                                                  "invalid `crate_type` value");
1230                              None
1231                          }
1232                          _ => {
1233                              session.struct_span_err(a.span, "`crate_type` requires a value")
1234                                  .note("for example: `#![crate_type=\"lib\"]`")
1235                                  .emit();
1236                              None
1237                          }
1238                      }
1239                  } else {
1240                      None
1241                  }
1242              })
1243              .collect();
1244
1245     // If we're generating a test executable, then ignore all other output
1246     // styles at all other locations
1247     if session.opts.test {
1248         return vec![config::CrateTypeExecutable];
1249     }
1250
1251     // Only check command line flags if present. If no types are specified by
1252     // command line, then reuse the empty `base` Vec to hold the types that
1253     // will be found in crate attributes.
1254     let mut base = session.opts.crate_types.clone();
1255     if base.is_empty() {
1256         base.extend(attr_types);
1257         if base.is_empty() {
1258             base.push(::rustc_trans_utils::link::default_output_for_target(session));
1259         }
1260         base.sort();
1261         base.dedup();
1262     }
1263
1264     base.into_iter()
1265         .filter(|crate_type| {
1266             let res = !rustc_trans_utils::link::invalid_output_for_target(session, *crate_type);
1267
1268             if !res {
1269                 session.warn(&format!("dropping unsupported crate type `{}` for target `{}`",
1270                                       *crate_type,
1271                                       session.opts.target_triple));
1272             }
1273
1274             res
1275         })
1276         .collect()
1277 }
1278
1279 pub fn compute_crate_disambiguator(session: &Session) -> String {
1280     use std::hash::Hasher;
1281
1282     // The crate_disambiguator is a 128 bit hash. The disambiguator is fed
1283     // into various other hashes quite a bit (symbol hashes, incr. comp. hashes,
1284     // debuginfo type IDs, etc), so we don't want it to be too wide. 128 bits
1285     // should still be safe enough to avoid collisions in practice.
1286     // FIXME(mw): It seems that the crate_disambiguator is used everywhere as
1287     //            a hex-string instead of raw bytes. We should really use the
1288     //            smaller representation.
1289     let mut hasher = StableHasher::<Fingerprint>::new();
1290
1291     let mut metadata = session.opts.cg.metadata.clone();
1292     // We don't want the crate_disambiguator to dependent on the order
1293     // -C metadata arguments, so sort them:
1294     metadata.sort();
1295     // Every distinct -C metadata value is only incorporated once:
1296     metadata.dedup();
1297
1298     hasher.write(b"metadata");
1299     for s in &metadata {
1300         // Also incorporate the length of a metadata string, so that we generate
1301         // different values for `-Cmetadata=ab -Cmetadata=c` and
1302         // `-Cmetadata=a -Cmetadata=bc`
1303         hasher.write_usize(s.len());
1304         hasher.write(s.as_bytes());
1305     }
1306
1307     // If this is an executable, add a special suffix, so that we don't get
1308     // symbol conflicts when linking against a library of the same name.
1309     let is_exe = session.crate_types.borrow().contains(&config::CrateTypeExecutable);
1310
1311     format!("{}{}", hasher.finish().to_hex(), if is_exe { "-exe" } else {""})
1312 }
1313
1314 pub fn build_output_filenames(input: &Input,
1315                               odir: &Option<PathBuf>,
1316                               ofile: &Option<PathBuf>,
1317                               attrs: &[ast::Attribute],
1318                               sess: &Session)
1319                               -> OutputFilenames {
1320     match *ofile {
1321         None => {
1322             // "-" as input file will cause the parser to read from stdin so we
1323             // have to make up a name
1324             // We want to toss everything after the final '.'
1325             let dirpath = match *odir {
1326                 Some(ref d) => d.clone(),
1327                 None => PathBuf::new(),
1328             };
1329
1330             // If a crate name is present, we use it as the link name
1331             let stem = sess.opts
1332                            .crate_name
1333                            .clone()
1334                            .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
1335                            .unwrap_or(input.filestem());
1336
1337             OutputFilenames {
1338                 out_directory: dirpath,
1339                 out_filestem: stem,
1340                 single_output_file: None,
1341                 extra: sess.opts.cg.extra_filename.clone(),
1342                 outputs: sess.opts.output_types.clone(),
1343             }
1344         }
1345
1346         Some(ref out_file) => {
1347             let unnamed_output_types = sess.opts
1348                                            .output_types
1349                                            .values()
1350                                            .filter(|a| a.is_none())
1351                                            .count();
1352             let ofile = if unnamed_output_types > 1 {
1353                 sess.warn("due to multiple output types requested, the explicitly specified \
1354                            output file name will be adapted for each output type");
1355                 None
1356             } else {
1357                 Some(out_file.clone())
1358             };
1359             if *odir != None {
1360                 sess.warn("ignoring --out-dir flag due to -o flag.");
1361             }
1362
1363             let cur_dir = Path::new("");
1364
1365             OutputFilenames {
1366                 out_directory: out_file.parent().unwrap_or(cur_dir).to_path_buf(),
1367                 out_filestem: out_file.file_stem()
1368                                       .unwrap_or(OsStr::new(""))
1369                                       .to_str()
1370                                       .unwrap()
1371                                       .to_string(),
1372                 single_output_file: ofile,
1373                 extra: sess.opts.cg.extra_filename.clone(),
1374                 outputs: sess.opts.output_types.clone(),
1375             }
1376         }
1377     }
1378 }