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;
  13 use rustc::hir::{map as hir_map, FreevarMap, TraitMap};
  14 use rustc::hir::def::DefMap;
  15 use rustc::hir::lowering::lower_crate;
  16 use rustc_mir as mir;
  17 use rustc::mir::mir_map::MirMap;
  18 use rustc::session::{Session, CompileResult, compile_result_from_err_count};
  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, dependency_format, stability, reachable};
  23 use rustc::middle::privacy::AccessLevels;
  24 use rustc::ty::{self, TyCtxt};
  25 use rustc::util::common::time;
  26 use rustc::util::nodemap::NodeSet;
  27 use rustc_back::sha2::{Sha256, Digest};
  28 use rustc_borrowck as borrowck;
  29 use rustc_incremental;
  30 use rustc_resolve as resolve;
  31 use rustc_metadata::macro_import;
  32 use rustc_metadata::creader::read_local_crates;
  33 use rustc_metadata::cstore::CStore;
  34 use rustc_trans::back::{link, write};
  35 use rustc_trans as trans;
  36 use rustc_typeck as typeck;
  37 use rustc_privacy;
  38 use rustc_plugin::registry::Registry;
  39 use rustc_plugin as plugin;
  40 use rustc_passes::{ast_validation, no_asm, loops, consts, rvalues, static_recursion};
  41 use rustc_const_eval::check_match;
  42 use super::Compilation;
  43
  44 use serialize::json;
  45
  46 use std::collections::HashMap;
  47 use std::env;
  48 use std::ffi::{OsString, OsStr};
  49 use std::fs;
  50 use std::io::{self, Write};
  51 use std::path::{Path, PathBuf};
  52 use syntax::ast::{self, NodeIdAssigner};
  53 use syntax::attr::{self, AttrMetaMethods};
  54 use syntax::diagnostics;
  55 use syntax::fold::Folder;
  56 use syntax::parse::{self, PResult, token};
  57 use syntax::util::node_count::NodeCounter;
  58 use syntax::visit;
  59 use syntax;
  60 use syntax_ext;
  61
  62 #[derive(Clone)]
  63 pub struct Resolutions {
  64     pub def_map: DefMap,
  65     pub freevars: FreevarMap,
  66     pub trait_map: TraitMap,
  67     pub maybe_unused_trait_imports: NodeSet,
  68 }
  69
  70 pub fn compile_input(sess: &Session,
  71                      cstore: &CStore,
  72                      cfg: ast::CrateConfig,
  73                      input: &Input,
  74                      outdir: &Option<PathBuf>,
  75                      output: &Option<PathBuf>,
  76                      addl_plugins: Option<Vec<String>>,
  77                      control: &CompileController) -> CompileResult {
  78     macro_rules! controller_entry_point {
  79         ($point: ident, $tsess: expr, $make_state: expr, $phase_result: expr) => {{
  80             let state = &mut $make_state;
  81             let phase_result: &CompileResult = &$phase_result;
  82             if phase_result.is_ok() || control.$point.run_callback_on_error {
  83                 (control.$point.callback)(state);
  84             }
  85
  86             if control.$point.stop == Compilation::Stop {
  87                 return compile_result_from_err_count($tsess.err_count());
  88             }
  89         }}
  90     }
  91
  92     // We need nested scopes here, because the intermediate results can keep
  93     // large chunks of memory alive and we want to free them as soon as
  94     // possible to keep the peak memory usage low
  95     let (outputs, trans) = {
  96         let krate = match phase_1_parse_input(sess, cfg, input) {
  97             Ok(krate) => krate,
  98             Err(mut parse_error) => {
  99                 parse_error.emit();
 100                 return Err(1);
 101             }
 102         };
 103
 104         let krate = {
 105             let mut compile_state = CompileState::state_after_parse(input,
 106                                                                     sess,
 107                                                                     outdir,
 108                                                                     output,
 109                                                                     krate,
 110                                                                     &cstore);
 111             controller_entry_point!(after_parse,
 112                                     sess,
 113                                     compile_state,
 114                                     Ok(()));
 115
 116             compile_state.krate.unwrap()
 117         };
 118
 119         let outputs = build_output_filenames(input, outdir, output, &krate.attrs, sess);
 120         let id = link::find_crate_name(Some(sess), &krate.attrs, input);
 121         let ExpansionResult { expanded_crate, defs, analysis, resolutions, mut hir_forest } = {
 122             let make_glob_map = control.make_glob_map;
 123             phase_2_configure_and_expand(sess, &cstore, krate, &id, addl_plugins, make_glob_map)?
 124         };
 125
 126         controller_entry_point!(after_expand,
 127                                 sess,
 128                                 CompileState::state_after_expand(input,
 129                                                                  sess,
 130                                                                  outdir,
 131                                                                  output,
 132                                                                  &cstore,
 133                                                                  &expanded_crate,
 134                                                                  &id),
 135                                 Ok(()));
 136
 137         write_out_deps(sess, &outputs, &id);
 138
 139         controller_entry_point!(after_write_deps,
 140                                 sess,
 141                                 CompileState::state_after_write_deps(input,
 142                                                                      sess,
 143                                                                      outdir,
 144                                                                      output,
 145                                                                      &cstore,
 146                                                                      &expanded_crate,
 147                                                                      &id),
 148                                 Ok(()));
 149
 150         let arenas = ty::CtxtArenas::new();
 151
 152         // Construct the HIR map
 153         let hir_map = time(sess.time_passes(),
 154                            "indexing hir",
 155                            || hir_map::map_crate(&mut hir_forest, defs));
 156
 157         {
 158             let _ignore = hir_map.dep_graph.in_ignore();
 159             controller_entry_point!(after_hir_lowering,
 160                                     sess,
 161                                     CompileState::state_after_hir_lowering(input,
 162                                                                   sess,
 163                                                                   outdir,
 164                                                                   output,
 165                                                                   &arenas,
 166                                                                   &cstore,
 167                                                                   &hir_map,
 168                                                                   &analysis,
 169                                                                   &resolutions,
 170                                                                   &expanded_crate,
 171                                                                   &hir_map.krate(),
 172                                                                   &id),
 173                                     Ok(()));
 174         }
 175
 176         time(sess.time_passes(), "attribute checking", || {
 177             hir::check_attr::check_crate(sess, &expanded_crate);
 178         });
 179
 180         let opt_crate = if keep_ast(sess) {
 181             Some(&expanded_crate)
 182         } else {
 183             drop(expanded_crate);
 184             None
 185         };
 186
 187         phase_3_run_analysis_passes(sess,
 188                                     hir_map,
 189                                     analysis,
 190                                     resolutions,
 191                                     &arenas,
 192                                     &id,
 193                                     |tcx, mir_map, analysis, result| {
 194             {
 195                 // Eventually, we will want to track plugins.
 196                 let _ignore = tcx.dep_graph.in_ignore();
 197
 198                 let mut state = CompileState::state_after_analysis(input,
 199                                                                    sess,
 200                                                                    outdir,
 201                                                                    output,
 202                                                                    opt_crate,
 203                                                                    tcx.map.krate(),
 204                                                                    &analysis,
 205                                                                    mir_map.as_ref(),
 206                                                                    tcx,
 207                                                                    &id);
 208                 (control.after_analysis.callback)(&mut state);
 209
 210                 if control.after_analysis.stop == Compilation::Stop {
 211                     return result.and_then(|_| Err(0usize));
 212                 }
 213             }
 214
 215             result?;
 216
 217             if log_enabled!(::log::INFO) {
 218                 println!("Pre-trans");
 219                 tcx.print_debug_stats();
 220             }
 221             let trans = phase_4_translate_to_llvm(tcx,
 222                                                   mir_map.unwrap(),
 223                                                   analysis);
 224
 225             if log_enabled!(::log::INFO) {
 226                 println!("Post-trans");
 227                 tcx.print_debug_stats();
 228             }
 229
 230             // Discard interned strings as they are no longer required.
 231             token::get_ident_interner().clear();
 232
 233             Ok((outputs, trans))
 234         })??
 235     };
 236
 237     let phase5_result = phase_5_run_llvm_passes(sess, &trans, &outputs);
 238
 239     controller_entry_point!(after_llvm,
 240                             sess,
 241                             CompileState::state_after_llvm(input, sess, outdir, output, &trans),
 242                             phase5_result);
 243     phase5_result?;
 244
 245     phase_6_link_output(sess, &trans, &outputs);
 246
 247     Ok(())
 248 }
 249
 250 fn keep_mtwt_tables(sess: &Session) -> bool {
 251     sess.opts.debugging_opts.keep_mtwt_tables
 252 }
 253
 254 fn keep_ast(sess: &Session) -> bool {
 255     sess.opts.debugging_opts.keep_ast ||
 256     sess.opts.debugging_opts.save_analysis ||
 257     sess.opts.debugging_opts.save_analysis_csv
 258 }
 259
 260 /// The name used for source code that doesn't originate in a file
 261 /// (e.g. source from stdin or a string)
 262 pub fn anon_src() -> String {
 263     "<anon>".to_string()
 264 }
 265
 266 pub fn source_name(input: &Input) -> String {
 267     match *input {
 268         // FIXME (#9639): This needs to handle non-utf8 paths
 269         Input::File(ref ifile) => ifile.to_str().unwrap().to_string(),
 270         Input::Str { ref name, .. } => name.clone(),
 271     }
 272 }
 273
 274 /// CompileController is used to customise compilation, it allows compilation to
 275 /// be stopped and/or to call arbitrary code at various points in compilation.
 276 /// It also allows for various flags to be set to influence what information gets
 277 /// collected during compilation.
 278 ///
 279 /// This is a somewhat higher level controller than a Session - the Session
 280 /// controls what happens in each phase, whereas the CompileController controls
 281 /// whether a phase is run at all and whether other code (from outside the
 282 /// the compiler) is run between phases.
 283 ///
 284 /// Note that if compilation is set to stop and a callback is provided for a
 285 /// given entry point, the callback is called before compilation is stopped.
 286 ///
 287 /// Expect more entry points to be added in the future.
 288 pub struct CompileController<'a> {
 289     pub after_parse: PhaseController<'a>,
 290     pub after_expand: PhaseController<'a>,
 291     pub after_write_deps: PhaseController<'a>,
 292     pub after_hir_lowering: PhaseController<'a>,
 293     pub after_analysis: PhaseController<'a>,
 294     pub after_llvm: PhaseController<'a>,
 295
 296     pub make_glob_map: resolve::MakeGlobMap,
 297 }
 298
 299 impl<'a> CompileController<'a> {
 300     pub fn basic() -> CompileController<'a> {
 301         CompileController {
 302             after_parse: PhaseController::basic(),
 303             after_expand: PhaseController::basic(),
 304             after_write_deps: PhaseController::basic(),
 305             after_hir_lowering: PhaseController::basic(),
 306             after_analysis: PhaseController::basic(),
 307             after_llvm: PhaseController::basic(),
 308             make_glob_map: resolve::MakeGlobMap::No,
 309         }
 310     }
 311 }
 312
 313 pub struct PhaseController<'a> {
 314     pub stop: Compilation,
 315     // If true then the compiler will try to run the callback even if the phase
 316     // ends with an error. Note that this is not always possible.
 317     pub run_callback_on_error: bool,
 318     pub callback: Box<Fn(&mut CompileState) + 'a>,
 319 }
 320
 321 impl<'a> PhaseController<'a> {
 322     pub fn basic() -> PhaseController<'a> {
 323         PhaseController {
 324             stop: Compilation::Continue,
 325             run_callback_on_error: false,
 326             callback: box |_| {},
 327         }
 328     }
 329 }
 330
 331 /// State that is passed to a callback. What state is available depends on when
 332 /// during compilation the callback is made. See the various constructor methods
 333 /// (`state_*`) in the impl to see which data is provided for any given entry point.
 334 pub struct CompileState<'a, 'b, 'ast: 'a, 'tcx: 'b> where 'ast: 'tcx {
 335     pub input: &'a Input,
 336     pub session: &'ast Session,
 337     pub krate: Option<ast::Crate>,
 338     pub cstore: Option<&'a CStore>,
 339     pub crate_name: Option<&'a str>,
 340     pub output_filenames: Option<&'a OutputFilenames>,
 341     pub out_dir: Option<&'a Path>,
 342     pub out_file: Option<&'a Path>,
 343     pub arenas: Option<&'ast ty::CtxtArenas<'ast>>,
 344     pub expanded_crate: Option<&'a ast::Crate>,
 345     pub hir_crate: Option<&'a hir::Crate>,
 346     pub ast_map: Option<&'a hir_map::Map<'ast>>,
 347     pub resolutions: Option<&'a Resolutions>,
 348     pub mir_map: Option<&'b MirMap<'tcx>>,
 349     pub analysis: Option<&'a ty::CrateAnalysis<'a>>,
 350     pub tcx: Option<TyCtxt<'b, 'tcx, 'tcx>>,
 351     pub trans: Option<&'a trans::CrateTranslation>,
 352 }
 353
 354 impl<'a, 'b, 'ast, 'tcx> CompileState<'a, 'b, 'ast, 'tcx> {
 355     fn empty(input: &'a Input,
 356              session: &'ast Session,
 357              out_dir: &'a Option<PathBuf>)
 358              -> CompileState<'a, 'b, 'ast, 'tcx> {
 359         CompileState {
 360             input: input,
 361             session: session,
 362             out_dir: out_dir.as_ref().map(|s| &**s),
 363             out_file: None,
 364             arenas: None,
 365             krate: None,
 366             cstore: None,
 367             crate_name: None,
 368             output_filenames: None,
 369             expanded_crate: None,
 370             hir_crate: None,
 371             ast_map: None,
 372             resolutions: None,
 373             analysis: None,
 374             mir_map: None,
 375             tcx: None,
 376             trans: None,
 377         }
 378     }
 379
 380     fn state_after_parse(input: &'a Input,
 381                          session: &'ast Session,
 382                          out_dir: &'a Option<PathBuf>,
 383                          out_file: &'a Option<PathBuf>,
 384                          krate: ast::Crate,
 385                          cstore: &'a CStore)
 386                          -> CompileState<'a, 'b, 'ast, 'tcx> {
 387         CompileState {
 388             krate: Some(krate),
 389             cstore: Some(cstore),
 390             out_file: out_file.as_ref().map(|s| &**s),
 391             ..CompileState::empty(input, session, out_dir)
 392         }
 393     }
 394
 395     fn state_after_expand(input: &'a Input,
 396                           session: &'ast Session,
 397                           out_dir: &'a Option<PathBuf>,
 398                           out_file: &'a Option<PathBuf>,
 399                           cstore: &'a CStore,
 400                           expanded_crate: &'a ast::Crate,
 401                           crate_name: &'a str)
 402                           -> CompileState<'a, 'b, 'ast, 'tcx> {
 403         CompileState {
 404             crate_name: Some(crate_name),
 405             cstore: Some(cstore),
 406             expanded_crate: Some(expanded_crate),
 407             out_file: out_file.as_ref().map(|s| &**s),
 408             ..CompileState::empty(input, session, out_dir)
 409         }
 410     }
 411
 412     fn state_after_write_deps(input: &'a Input,
 413                               session: &'ast Session,
 414                               out_dir: &'a Option<PathBuf>,
 415                               out_file: &'a Option<PathBuf>,
 416                               cstore: &'a CStore,
 417                               krate: &'a ast::Crate,
 418                               crate_name: &'a str)
 419                               -> CompileState<'a, 'b, 'ast, 'tcx> {
 420         CompileState {
 421             crate_name: Some(crate_name),
 422             cstore: Some(cstore),
 423             expanded_crate: Some(krate),
 424             out_file: out_file.as_ref().map(|s| &**s),
 425             ..CompileState::empty(input, session, out_dir)
 426         }
 427     }
 428
 429     fn state_after_hir_lowering(input: &'a Input,
 430                                 session: &'ast Session,
 431                                 out_dir: &'a Option<PathBuf>,
 432                                 out_file: &'a Option<PathBuf>,
 433                                 arenas: &'ast ty::CtxtArenas<'ast>,
 434                                 cstore: &'a CStore,
 435                                 hir_map: &'a hir_map::Map<'ast>,
 436                                 analysis: &'a ty::CrateAnalysis,
 437                                 resolutions: &'a Resolutions,
 438                                 krate: &'a ast::Crate,
 439                                 hir_crate: &'a hir::Crate,
 440                                 crate_name: &'a str)
 441                                 -> CompileState<'a, 'b, 'ast, 'tcx> {
 442         CompileState {
 443             crate_name: Some(crate_name),
 444             arenas: Some(arenas),
 445             cstore: Some(cstore),
 446             ast_map: Some(hir_map),
 447             analysis: Some(analysis),
 448             resolutions: Some(resolutions),
 449             expanded_crate: Some(krate),
 450             hir_crate: Some(hir_crate),
 451             out_file: out_file.as_ref().map(|s| &**s),
 452             ..CompileState::empty(input, session, out_dir)
 453         }
 454     }
 455
 456     fn state_after_analysis(input: &'a Input,
 457                             session: &'ast Session,
 458                             out_dir: &'a Option<PathBuf>,
 459                             out_file: &'a Option<PathBuf>,
 460                             krate: Option<&'a ast::Crate>,
 461                             hir_crate: &'a hir::Crate,
 462                             analysis: &'a ty::CrateAnalysis<'a>,
 463                             mir_map: Option<&'b MirMap<'tcx>>,
 464                             tcx: TyCtxt<'b, 'tcx, 'tcx>,
 465                             crate_name: &'a str)
 466                             -> CompileState<'a, 'b, 'ast, 'tcx> {
 467         CompileState {
 468             analysis: Some(analysis),
 469             mir_map: mir_map,
 470             tcx: Some(tcx),
 471             expanded_crate: krate,
 472             hir_crate: Some(hir_crate),
 473             crate_name: Some(crate_name),
 474             out_file: out_file.as_ref().map(|s| &**s),
 475             ..CompileState::empty(input, session, out_dir)
 476         }
 477     }
 478
 479
 480     fn state_after_llvm(input: &'a Input,
 481                         session: &'ast Session,
 482                         out_dir: &'a Option<PathBuf>,
 483                         out_file: &'a Option<PathBuf>,
 484                         trans: &'a trans::CrateTranslation)
 485                         -> CompileState<'a, 'b, 'ast, 'tcx> {
 486         CompileState {
 487             trans: Some(trans),
 488             out_file: out_file.as_ref().map(|s| &**s),
 489             ..CompileState::empty(input, session, out_dir)
 490         }
 491     }
 492 }
 493
 494 pub fn phase_1_parse_input<'a>(sess: &'a Session,
 495                                cfg: ast::CrateConfig,
 496                                input: &Input)
 497                                -> PResult<'a, ast::Crate> {
 498     // These may be left in an incoherent state after a previous compile.
 499     // `clear_tables` and `get_ident_interner().clear()` can be used to free
 500     // memory, but they do not restore the initial state.
 501     syntax::ext::mtwt::reset_tables();
 502     token::reset_ident_interner();
 503     let continue_after_error = sess.opts.continue_parse_after_error;
 504     sess.diagnostic().set_continue_after_error(continue_after_error);
 505
 506     let krate = time(sess.time_passes(), "parsing", || {
 507         match *input {
 508             Input::File(ref file) => {
 509                 parse::parse_crate_from_file(file, cfg.clone(), &sess.parse_sess)
 510             }
 511             Input::Str { ref input, ref name } => {
 512                 parse::parse_crate_from_source_str(name.clone(),
 513                                                    input.clone(),
 514                                                    cfg.clone(),
 515                                                    &sess.parse_sess)
 516             }
 517         }
 518     })?;
 519
 520     sess.diagnostic().set_continue_after_error(true);
 521
 522     if sess.opts.debugging_opts.ast_json_noexpand {
 523         println!("{}", json::as_json(&krate));
 524     }
 525
 526     if sess.opts.debugging_opts.input_stats {
 527         println!("Lines of code:             {}", sess.codemap().count_lines());
 528         println!("Pre-expansion node count:  {}", count_nodes(&krate));
 529     }
 530
 531     if let Some(ref s) = sess.opts.debugging_opts.show_span {
 532         syntax::show_span::run(sess.diagnostic(), s, &krate);
 533     }
 534
 535     Ok(krate)
 536 }
 537
 538 fn count_nodes(krate: &ast::Crate) -> usize {
 539     let mut counter = NodeCounter::new();
 540     visit::walk_crate(&mut counter, krate);
 541     counter.count
 542 }
 543
 544 // For continuing compilation after a parsed crate has been
 545 // modified
 546
 547 pub struct ExpansionResult<'a> {
 548     pub expanded_crate: ast::Crate,
 549     pub defs: hir_map::Definitions,
 550     pub analysis: ty::CrateAnalysis<'a>,
 551     pub resolutions: Resolutions,
 552     pub hir_forest: hir_map::Forest,
 553 }
 554
 555 /// Run the "early phases" of the compiler: initial `cfg` processing,
 556 /// loading compiler plugins (including those from `addl_plugins`),
 557 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 558 /// harness if one is to be provided, injection of a dependency on the
 559 /// standard library and prelude, and name resolution.
 560 ///
 561 /// Returns `None` if we're aborting after handling -W help.
 562 pub fn phase_2_configure_and_expand<'a>(sess: &Session,
 563                                         cstore: &CStore,
 564                                         mut krate: ast::Crate,
 565                                         crate_name: &'a str,
 566                                         addl_plugins: Option<Vec<String>>,
 567                                         make_glob_map: resolve::MakeGlobMap)
 568                                         -> Result<ExpansionResult<'a>, usize> {
 569     let time_passes = sess.time_passes();
 570
 571     // strip before anything else because crate metadata may use #[cfg_attr]
 572     // and so macros can depend on configuration variables, such as
 573     //
 574     //   #[macro_use] #[cfg(foo)]
 575     //   mod bar { macro_rules! baz!(() => {{}}) }
 576     //
 577     // baz! should not use this definition unless foo is enabled.
 578
 579     krate = time(time_passes, "configuration", || {
 580         let (krate, features) =
 581             syntax::config::strip_unconfigured_items(krate, &sess.parse_sess, sess.opts.test);
 582         // these need to be set "early" so that expansion sees `quote` if enabled.
 583         *sess.features.borrow_mut() = features;
 584         krate
 585     });
 586
 587     *sess.crate_types.borrow_mut() = collect_crate_types(sess, &krate.attrs);
 588     sess.crate_disambiguator.set(token::intern(&compute_crate_disambiguator(sess)));
 589
 590     time(time_passes, "recursion limit", || {
 591         middle::recursion_limit::update_recursion_limit(sess, &krate);
 592     });
 593
 594     krate = time(time_passes, "crate injection", || {
 595         let alt_std_name = sess.opts.alt_std_name.clone();
 596         syntax::std_inject::maybe_inject_crates_ref(&sess.parse_sess, krate, alt_std_name)
 597     });
 598
 599     let mut addl_plugins = Some(addl_plugins);
 600     let registrars = time(time_passes, "plugin loading", || {
 601         plugin::load::load_plugins(sess,
 602                                    &cstore,
 603                                    &krate,
 604                                    crate_name,
 605                                    addl_plugins.take().unwrap())
 606     });
 607
 608     let mut registry = Registry::new(sess, &krate);
 609
 610     time(time_passes, "plugin registration", || {
 611         if sess.features.borrow().rustc_diagnostic_macros {
 612             registry.register_macro("__diagnostic_used",
 613                                     diagnostics::plugin::expand_diagnostic_used);
 614             registry.register_macro("__register_diagnostic",
 615                                     diagnostics::plugin::expand_register_diagnostic);
 616             registry.register_macro("__build_diagnostic_array",
 617                                     diagnostics::plugin::expand_build_diagnostic_array);
 618         }
 619
 620         for registrar in registrars {
 621             registry.args_hidden = Some(registrar.args);
 622             (registrar.fun)(&mut registry);
 623         }
 624     });
 625
 626     let Registry { syntax_exts, early_lint_passes, late_lint_passes, lint_groups,
 627                    llvm_passes, attributes, mir_passes, .. } = registry;
 628
 629     sess.track_errors(|| {
 630         let mut ls = sess.lint_store.borrow_mut();
 631         for pass in early_lint_passes {
 632             ls.register_early_pass(Some(sess), true, pass);
 633         }
 634         for pass in late_lint_passes {
 635             ls.register_late_pass(Some(sess), true, pass);
 636         }
 637
 638         for (name, to) in lint_groups {
 639             ls.register_group(Some(sess), true, name, to);
 640         }
 641
 642         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
 643         sess.mir_passes.borrow_mut().extend(mir_passes);
 644         *sess.plugin_attributes.borrow_mut() = attributes.clone();
 645     })?;
 646
 647     // Lint plugins are registered; now we can process command line flags.
 648     if sess.opts.describe_lints {
 649         super::describe_lints(&sess.lint_store.borrow(), true);
 650         return Err(0);
 651     }
 652     sess.track_errors(|| sess.lint_store.borrow_mut().process_command_line(sess))?;
 653
 654     krate = time(time_passes, "expansion", || {
 655         // Windows dlls do not have rpaths, so they don't know how to find their
 656         // dependencies. It's up to us to tell the system where to find all the
 657         // dependent dlls. Note that this uses cfg!(windows) as opposed to
 658         // targ_cfg because syntax extensions are always loaded for the host
 659         // compiler, not for the target.
 660         //
 661         // This is somewhat of an inherently racy operation, however, as
 662         // multiple threads calling this function could possibly continue
 663         // extending PATH far beyond what it should. To solve this for now we
 664         // just don't add any new elements to PATH which are already there
 665         // within PATH. This is basically a targeted fix at #17360 for rustdoc
 666         // which runs rustc in parallel but has been seen (#33844) to cause
 667         // problems with PATH becoming too long.
 668         let mut old_path = OsString::new();
 669         if cfg!(windows) {
 670             old_path = env::var_os("PATH").unwrap_or(old_path);
 671             let mut new_path = sess.host_filesearch(PathKind::All)
 672                                    .get_dylib_search_paths();
 673             for path in env::split_paths(&old_path) {
 674                 if !new_path.contains(&path) {
 675                     new_path.push(path);
 676                 }
 677             }
 678             env::set_var("PATH", &env::join_paths(new_path).unwrap());
 679         }
 680         let features = sess.features.borrow();
 681         let cfg = syntax::ext::expand::ExpansionConfig {
 682             crate_name: crate_name.to_string(),
 683             features: Some(&features),
 684             recursion_limit: sess.recursion_limit.get(),
 685             trace_mac: sess.opts.debugging_opts.trace_macros,
 686             should_test: sess.opts.test,
 687         };
 688         let mut loader = macro_import::MacroLoader::new(sess, &cstore, crate_name);
 689         let mut ecx = syntax::ext::base::ExtCtxt::new(&sess.parse_sess,
 690                                                       krate.config.clone(),
 691                                                       cfg,
 692                                                       &mut loader);
 693         syntax_ext::register_builtins(&mut ecx.syntax_env);
 694         let (ret, macro_names) = syntax::ext::expand::expand_crate(ecx,
 695                                                                    syntax_exts,
 696                                                                    krate);
 697         if cfg!(windows) {
 698             env::set_var("PATH", &old_path);
 699         }
 700         *sess.available_macros.borrow_mut() = macro_names;
 701         ret
 702     });
 703
 704     krate = time(time_passes, "maybe building test harness", || {
 705         syntax::test::modify_for_testing(&sess.parse_sess,
 706                                          sess.opts.test,
 707                                          krate,
 708                                          sess.diagnostic())
 709     });
 710
 711     time(time_passes,
 712          "checking for inline asm in case the target doesn't support it",
 713          || no_asm::check_crate(sess, &krate));
 714
 715     // Needs to go *after* expansion to be able to check the results of macro expansion.
 716     time(time_passes, "complete gated feature checking", || {
 717         sess.track_errors(|| {
 718             syntax::feature_gate::check_crate(&krate,
 719                                               &sess.parse_sess,
 720                                               &sess.features.borrow(),
 721                                               &attributes,
 722                                               sess.opts.unstable_features);
 723         })
 724     })?;
 725
 726     if sess.opts.debugging_opts.input_stats {
 727         println!("Post-expansion node count: {}", count_nodes(&krate));
 728     }
 729
 730     krate = assign_node_ids(sess, krate);
 731
 732     // Collect defintions for def ids.
 733     let mut defs =
 734         time(sess.time_passes(), "collecting defs", || hir_map::collect_definitions(&krate));
 735
 736     time(sess.time_passes(),
 737          "external crate/lib resolution",
 738          || read_local_crates(sess, &cstore, &defs, &krate, crate_name, &sess.dep_graph));
 739
 740     time(sess.time_passes(),
 741          "early lint checks",
 742          || lint::check_ast_crate(sess, &krate));
 743
 744     time(sess.time_passes(),
 745          "AST validation",
 746          || ast_validation::check_crate(sess, &krate));
 747
 748     let (analysis, resolutions, hir_forest) =
 749         lower_and_resolve(sess, crate_name, &mut defs, &krate, &sess.dep_graph, make_glob_map);
 750
 751     // Discard MTWT tables that aren't required past lowering to HIR.
 752     if !keep_mtwt_tables(sess) {
 753         syntax::ext::mtwt::clear_tables();
 754     }
 755
 756     Ok(ExpansionResult {
 757         expanded_crate: krate,
 758         defs: defs,
 759         analysis: analysis,
 760         resolutions: resolutions,
 761         hir_forest: hir_forest
 762     })
 763 }
 764
 765 pub fn assign_node_ids(sess: &Session, krate: ast::Crate) -> ast::Crate {
 766     use syntax::ptr::P;
 767     use syntax::util::move_map::MoveMap;
 768
 769     struct NodeIdAssigner<'a> {
 770         sess: &'a Session,
 771     }
 772
 773     impl<'a> Folder for NodeIdAssigner<'a> {
 774         fn new_id(&mut self, old_id: ast::NodeId) -> ast::NodeId {
 775             assert_eq!(old_id, ast::DUMMY_NODE_ID);
 776             self.sess.next_node_id()
 777         }
 778
 779         fn fold_block(&mut self, block: P<ast::Block>) -> P<ast::Block> {
 780             block.map(|mut block| {
 781                 block.id = self.new_id(block.id);
 782
 783                 let stmt = block.stmts.pop();
 784                 block.stmts = block.stmts.move_flat_map(|s| self.fold_stmt(s).into_iter());
 785                 if let Some(ast::Stmt { node: ast::StmtKind::Expr(expr), span, .. }) = stmt {
 786                     let expr = self.fold_expr(expr);
 787                     block.stmts.push(ast::Stmt {
 788                         id: expr.id,
 789                         node: ast::StmtKind::Expr(expr),
 790                         span: span,
 791                     });
 792                 } else if let Some(stmt) = stmt {
 793                     block.stmts.extend(self.fold_stmt(stmt));
 794                 }
 795
 796                 block
 797             })
 798         }
 799     }
 800
 801     let krate = time(sess.time_passes(),
 802                      "assigning node ids",
 803                      || NodeIdAssigner { sess: sess }.fold_crate(krate));
 804
 805     if sess.opts.debugging_opts.ast_json {
 806         println!("{}", json::as_json(&krate));
 807     }
 808
 809     krate
 810 }
 811
 812 pub fn lower_and_resolve<'a>(sess: &Session,
 813                              id: &'a str,
 814                              defs: &mut hir_map::Definitions,
 815                              krate: &ast::Crate,
 816                              dep_graph: &DepGraph,
 817                              make_glob_map: resolve::MakeGlobMap)
 818                              -> (ty::CrateAnalysis<'a>, Resolutions, hir_map::Forest) {
 819     resolve::with_resolver(sess, defs, make_glob_map, |mut resolver| {
 820         time(sess.time_passes(), "name resolution", || {
 821             resolve::resolve_crate(&mut resolver, krate);
 822         });
 823
 824         // Lower ast -> hir.
 825         let hir_forest = time(sess.time_passes(), "lowering ast -> hir", || {
 826             hir_map::Forest::new(lower_crate(sess, krate, sess, &mut resolver), dep_graph)
 827         });
 828
 829         (ty::CrateAnalysis {
 830             export_map: resolver.export_map,
 831             access_levels: AccessLevels::default(),
 832             reachable: NodeSet(),
 833             name: &id,
 834             glob_map: if resolver.make_glob_map { Some(resolver.glob_map) } else { None },
 835         }, Resolutions {
 836             def_map: resolver.def_map,
 837             freevars: resolver.freevars,
 838             trait_map: resolver.trait_map,
 839             maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
 840         }, hir_forest)
 841     })
 842 }
 843
 844 /// Run the resolution, typechecking, region checking and other
 845 /// miscellaneous analysis passes on the crate. Return various
 846 /// structures carrying the results of the analysis.
 847 pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 848                                                hir_map: hir_map::Map<'tcx>,
 849                                                mut analysis: ty::CrateAnalysis,
 850                                                resolutions: Resolutions,
 851                                                arenas: &'tcx ty::CtxtArenas<'tcx>,
 852                                                name: &str,
 853                                                f: F)
 854                                                -> Result<R, usize>
 855     where F: for<'a> FnOnce(TyCtxt<'a, 'tcx, 'tcx>,
 856                             Option<MirMap<'tcx>>,
 857                             ty::CrateAnalysis,
 858                             CompileResult) -> R
 859 {
 860     macro_rules! try_with_f {
 861         ($e: expr, ($t: expr, $m: expr, $a: expr)) => {
 862             match $e {
 863                 Ok(x) => x,
 864                 Err(x) => {
 865                     f($t, $m, $a, Err(x));
 866                     return Err(x);
 867                 }
 868             }
 869         }
 870     }
 871
 872     let time_passes = sess.time_passes();
 873
 874     let lang_items = time(time_passes, "language item collection", || {
 875         sess.track_errors(|| {
 876             middle::lang_items::collect_language_items(&sess, &hir_map)
 877         })
 878     })?;
 879
 880     let named_region_map = time(time_passes,
 881                                 "lifetime resolution",
 882                                 || middle::resolve_lifetime::krate(sess,
 883                                                                    &hir_map,
 884                                                                    &resolutions.def_map))?;
 885
 886     time(time_passes,
 887          "looking for entry point",
 888          || middle::entry::find_entry_point(sess, &hir_map));
 889
 890     sess.plugin_registrar_fn.set(time(time_passes, "looking for plugin registrar", || {
 891         plugin::build::find_plugin_registrar(sess.diagnostic(), &hir_map)
 892     }));
 893
 894     let region_map = time(time_passes,
 895                           "region resolution",
 896                           || middle::region::resolve_crate(sess, &hir_map));
 897
 898     time(time_passes,
 899          "loop checking",
 900          || loops::check_crate(sess, &hir_map));
 901
 902     time(time_passes,
 903               "static item recursion checking",
 904               || static_recursion::check_crate(sess, &resolutions.def_map, &hir_map))?;
 905
 906     let index = stability::Index::new(&hir_map);
 907
 908     let trait_map = resolutions.trait_map;
 909     TyCtxt::create_and_enter(sess,
 910                              arenas,
 911                              resolutions.def_map,
 912                              named_region_map,
 913                              hir_map,
 914                              resolutions.freevars,
 915                              resolutions.maybe_unused_trait_imports,
 916                              region_map,
 917                              lang_items,
 918                              index,
 919                              name,
 920                              |tcx| {
 921         time(time_passes,
 922              "load_dep_graph",
 923              || rustc_incremental::load_dep_graph(tcx));
 924
 925         // passes are timed inside typeck
 926         try_with_f!(typeck::check_crate(tcx, trait_map), (tcx, None, analysis));
 927
 928         time(time_passes,
 929              "const checking",
 930              || consts::check_crate(tcx));
 931
 932         analysis.access_levels =
 933             time(time_passes, "privacy checking", || {
 934                 rustc_privacy::check_crate(tcx, &analysis.export_map)
 935             });
 936
 937         // Do not move this check past lint
 938         time(time_passes, "stability index", || {
 939             tcx.stability.borrow_mut().build(tcx, &analysis.access_levels)
 940         });
 941
 942         time(time_passes,
 943              "intrinsic checking",
 944              || middle::intrinsicck::check_crate(tcx));
 945
 946         time(time_passes,
 947              "effect checking",
 948              || middle::effect::check_crate(tcx));
 949
 950         time(time_passes,
 951              "match checking",
 952              || check_match::check_crate(tcx));
 953
 954         // this must run before MIR dump, because
 955         // "not all control paths return a value" is reported here.
 956         //
 957         // maybe move the check to a MIR pass?
 958         time(time_passes,
 959              "liveness checking",
 960              || middle::liveness::check_crate(tcx));
 961
 962         time(time_passes,
 963              "rvalue checking",
 964              || rvalues::check_crate(tcx));
 965
 966         let mut mir_map =
 967             time(time_passes,
 968                  "MIR dump",
 969                  || mir::mir_map::build_mir_for_crate(tcx));
 970
 971         time(time_passes, "MIR passes", || {
 972             let mut passes = sess.mir_passes.borrow_mut();
 973             // Push all the built-in passes.
 974             passes.push_hook(box mir::transform::dump_mir::DumpMir);
 975             passes.push_pass(box mir::transform::simplify_cfg::SimplifyCfg::new("initial"));
 976             passes.push_pass(box mir::transform::qualify_consts::QualifyAndPromoteConstants);
 977             passes.push_pass(box mir::transform::type_check::TypeckMir);
 978             passes.push_pass(
 979                 box mir::transform::simplify_branches::SimplifyBranches::new("initial"));
 980             passes.push_pass(box mir::transform::simplify_cfg::SimplifyCfg::new("qualify-consts"));
 981             // And run everything.
 982             passes.run_passes(tcx, &mut mir_map);
 983         });
 984
 985         time(time_passes,
 986              "borrow checking",
 987              || borrowck::check_crate(tcx, &mir_map));
 988
 989         // Avoid overwhelming user with errors if type checking failed.
 990         // I'm not sure how helpful this is, to be honest, but it avoids
 991         // a
 992         // lot of annoying errors in the compile-fail tests (basically,
 993         // lint warnings and so on -- kindck used to do this abort, but
 994         // kindck is gone now). -nmatsakis
 995         if sess.err_count() > 0 {
 996             return Ok(f(tcx, Some(mir_map), analysis, Err(sess.err_count())));
 997         }
 998
 999         analysis.reachable =
1000             time(time_passes,
1001                  "reachability checking",
1002                  || reachable::find_reachable(tcx, &analysis.access_levels));
1003
1004         time(time_passes, "death checking", || {
1005             middle::dead::check_crate(tcx, &analysis.access_levels);
1006         });
1007
1008         let ref lib_features_used =
1009             time(time_passes,
1010                  "stability checking",
1011                  || stability::check_unstable_api_usage(tcx));
1012
1013         time(time_passes, "unused lib feature checking", || {
1014             stability::check_unused_or_stable_features(&tcx.sess,
1015                                                        lib_features_used)
1016         });
1017
1018         time(time_passes,
1019              "lint checking",
1020              || lint::check_crate(tcx, &analysis.access_levels));
1021
1022         // The above three passes generate errors w/o aborting
1023         if sess.err_count() > 0 {
1024             return Ok(f(tcx, Some(mir_map), analysis, Err(sess.err_count())));
1025         }
1026
1027         Ok(f(tcx, Some(mir_map), analysis, Ok(())))
1028     })
1029 }
1030
1031 /// Run the translation phase to LLVM, after which the AST and analysis can
1032 pub fn phase_4_translate_to_llvm<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1033                                            mut mir_map: MirMap<'tcx>,
1034                                            analysis: ty::CrateAnalysis)
1035                                            -> trans::CrateTranslation {
1036     let time_passes = tcx.sess.time_passes();
1037
1038     time(time_passes,
1039          "resolving dependency formats",
1040          || dependency_format::calculate(&tcx.sess));
1041
1042     // Run the passes that transform the MIR into a more suitable for translation
1043     // to LLVM code.
1044     time(time_passes, "Prepare MIR codegen passes", || {
1045         let mut passes = ::rustc::mir::transform::Passes::new();
1046         passes.push_hook(box mir::transform::dump_mir::DumpMir);
1047         passes.push_pass(box mir::transform::no_landing_pads::NoLandingPads);
1048         passes.push_pass(box mir::transform::simplify_cfg::SimplifyCfg::new("no-landing-pads"));
1049
1050         passes.push_pass(box mir::transform::erase_regions::EraseRegions);
1051
1052         passes.push_pass(box mir::transform::add_call_guards::AddCallGuards);
1053         passes.push_pass(box borrowck::ElaborateDrops);
1054         passes.push_pass(box mir::transform::no_landing_pads::NoLandingPads);
1055         passes.push_pass(box mir::transform::simplify_cfg::SimplifyCfg::new("elaborate-drops"));
1056
1057         passes.push_pass(box mir::transform::add_call_guards::AddCallGuards);
1058         passes.push_pass(box mir::transform::dump_mir::Marker("PreTrans"));
1059
1060         passes.run_passes(tcx, &mut mir_map);
1061     });
1062
1063     let translation =
1064         time(time_passes,
1065              "translation",
1066              move || trans::trans_crate(tcx, &mir_map, analysis));
1067
1068     time(time_passes,
1069          "assert dep graph",
1070          move || rustc_incremental::assert_dep_graph(tcx));
1071
1072     time(time_passes,
1073          "serialize dep graph",
1074          move || rustc_incremental::save_dep_graph(tcx));
1075
1076     translation
1077 }
1078
1079 /// Run LLVM itself, producing a bitcode file, assembly file or object file
1080 /// as a side effect.
1081 pub fn phase_5_run_llvm_passes(sess: &Session,
1082                                trans: &trans::CrateTranslation,
1083                                outputs: &OutputFilenames) -> CompileResult {
1084     if sess.opts.cg.no_integrated_as {
1085         let mut map = HashMap::new();
1086         map.insert(OutputType::Assembly, None);
1087         time(sess.time_passes(),
1088              "LLVM passes",
1089              || write::run_passes(sess, trans, &map, outputs));
1090
1091         write::run_assembler(sess, outputs);
1092
1093         // Remove assembly source, unless --save-temps was specified
1094         if !sess.opts.cg.save_temps {
1095             fs::remove_file(&outputs.temp_path(OutputType::Assembly)).unwrap();
1096         }
1097     } else {
1098         time(sess.time_passes(),
1099              "LLVM passes",
1100              || write::run_passes(sess, trans, &sess.opts.output_types, outputs));
1101     }
1102
1103     if sess.err_count() > 0 {
1104         Err(sess.err_count())
1105     } else {
1106         Ok(())
1107     }
1108 }
1109
1110 /// Run the linker on any artifacts that resulted from the LLVM run.
1111 /// This should produce either a finished executable or library.
1112 pub fn phase_6_link_output(sess: &Session,
1113                            trans: &trans::CrateTranslation,
1114                            outputs: &OutputFilenames) {
1115     time(sess.time_passes(),
1116          "linking",
1117          || link::link_binary(sess, trans, outputs, &trans.link.crate_name));
1118 }
1119
1120 fn escape_dep_filename(filename: &str) -> String {
1121     // Apparently clang and gcc *only* escape spaces:
1122     // http://llvm.org/klaus/clang/commit/9d50634cfc268ecc9a7250226dd5ca0e945240d4
1123     filename.replace(" ", "\\ ")
1124 }
1125
1126 fn write_out_deps(sess: &Session, outputs: &OutputFilenames, id: &str) {
1127     let mut out_filenames = Vec::new();
1128     for output_type in sess.opts.output_types.keys() {
1129         let file = outputs.path(*output_type);
1130         match *output_type {
1131             OutputType::Exe => {
1132                 for output in sess.crate_types.borrow().iter() {
1133                     let p = link::filename_for_input(sess, *output, id, outputs);
1134                     out_filenames.push(p);
1135                 }
1136             }
1137             _ => {
1138                 out_filenames.push(file);
1139             }
1140         }
1141     }
1142
1143     // Write out dependency rules to the dep-info file if requested
1144     if !sess.opts.output_types.contains_key(&OutputType::DepInfo) {
1145         return;
1146     }
1147     let deps_filename = outputs.path(OutputType::DepInfo);
1148
1149     let result =
1150         (|| -> io::Result<()> {
1151             // Build a list of files used to compile the output and
1152             // write Makefile-compatible dependency rules
1153             let files: Vec<String> = sess.codemap()
1154                                          .files
1155                                          .borrow()
1156                                          .iter()
1157                                          .filter(|fmap| fmap.is_real_file())
1158                                          .filter(|fmap| !fmap.is_imported())
1159                                          .map(|fmap| escape_dep_filename(&fmap.name))
1160                                          .collect();
1161             let mut file = fs::File::create(&deps_filename)?;
1162             for path in &out_filenames {
1163                 write!(file, "{}: {}\n\n", path.display(), files.join(" "))?;
1164             }
1165
1166             // Emit a fake target for each input file to the compilation. This
1167             // prevents `make` from spitting out an error if a file is later
1168             // deleted. For more info see #28735
1169             for path in files {
1170                 writeln!(file, "{}:", path)?;
1171             }
1172             Ok(())
1173         })();
1174
1175     match result {
1176         Ok(()) => {}
1177         Err(e) => {
1178             sess.fatal(&format!("error writing dependencies to `{}`: {}",
1179                                 deps_filename.display(),
1180                                 e));
1181         }
1182     }
1183 }
1184
1185 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
1186     // Unconditionally collect crate types from attributes to make them used
1187     let attr_types: Vec<config::CrateType> =
1188         attrs.iter()
1189              .filter_map(|a| {
1190                  if a.check_name("crate_type") {
1191                      match a.value_str() {
1192                          Some(ref n) if *n == "rlib" => {
1193                              Some(config::CrateTypeRlib)
1194                          }
1195                          Some(ref n) if *n == "dylib" => {
1196                              Some(config::CrateTypeDylib)
1197                          }
1198                          Some(ref n) if *n == "cdylib" => {
1199                              Some(config::CrateTypeCdylib)
1200                          }
1201                          Some(ref n) if *n == "lib" => {
1202                              Some(config::default_lib_output())
1203                          }
1204                          Some(ref n) if *n == "staticlib" => {
1205                              Some(config::CrateTypeStaticlib)
1206                          }
1207                          Some(ref n) if *n == "bin" => Some(config::CrateTypeExecutable),
1208                          Some(_) => {
1209                              session.add_lint(lint::builtin::UNKNOWN_CRATE_TYPES,
1210                                               ast::CRATE_NODE_ID,
1211                                               a.span,
1212                                               "invalid `crate_type` value".to_string());
1213                              None
1214                          }
1215                          _ => {
1216                              session.struct_span_err(a.span, "`crate_type` requires a value")
1217                                  .note("for example: `#![crate_type=\"lib\"]`")
1218                                  .emit();
1219                              None
1220                          }
1221                      }
1222                  } else {
1223                      None
1224                  }
1225              })
1226              .collect();
1227
1228     // If we're generating a test executable, then ignore all other output
1229     // styles at all other locations
1230     if session.opts.test {
1231         return vec![config::CrateTypeExecutable];
1232     }
1233
1234     // Only check command line flags if present. If no types are specified by
1235     // command line, then reuse the empty `base` Vec to hold the types that
1236     // will be found in crate attributes.
1237     let mut base = session.opts.crate_types.clone();
1238     if base.is_empty() {
1239         base.extend(attr_types);
1240         if base.is_empty() {
1241             base.push(link::default_output_for_target(session));
1242         }
1243         base.sort();
1244         base.dedup();
1245     }
1246
1247     base.into_iter()
1248         .filter(|crate_type| {
1249             let res = !link::invalid_output_for_target(session, *crate_type);
1250
1251             if !res {
1252                 session.warn(&format!("dropping unsupported crate type `{}` for target `{}`",
1253                                       *crate_type,
1254                                       session.opts.target_triple));
1255             }
1256
1257             res
1258         })
1259         .collect()
1260 }
1261
1262 pub fn compute_crate_disambiguator(session: &Session) -> String {
1263     let mut hasher = Sha256::new();
1264
1265     let mut metadata = session.opts.cg.metadata.clone();
1266     // We don't want the crate_disambiguator to dependent on the order
1267     // -C metadata arguments, so sort them:
1268     metadata.sort();
1269     // Every distinct -C metadata value is only incorporated once:
1270     metadata.dedup();
1271
1272     hasher.input_str("metadata");
1273     for s in &metadata {
1274         // Also incorporate the length of a metadata string, so that we generate
1275         // different values for `-Cmetadata=ab -Cmetadata=c` and
1276         // `-Cmetadata=a -Cmetadata=bc`
1277         hasher.input_str(&format!("{}", s.len())[..]);
1278         hasher.input_str(&s[..]);
1279     }
1280
1281     let mut hash = hasher.result_str();
1282
1283     // If this is an executable, add a special suffix, so that we don't get
1284     // symbol conflicts when linking against a library of the same name.
1285     if session.crate_types.borrow().contains(&config::CrateTypeExecutable) {
1286        hash.push_str("-exe");
1287     }
1288
1289     hash
1290 }
1291
1292 pub fn build_output_filenames(input: &Input,
1293                               odir: &Option<PathBuf>,
1294                               ofile: &Option<PathBuf>,
1295                               attrs: &[ast::Attribute],
1296                               sess: &Session)
1297                               -> OutputFilenames {
1298     match *ofile {
1299         None => {
1300             // "-" as input file will cause the parser to read from stdin so we
1301             // have to make up a name
1302             // We want to toss everything after the final '.'
1303             let dirpath = match *odir {
1304                 Some(ref d) => d.clone(),
1305                 None => PathBuf::new(),
1306             };
1307
1308             // If a crate name is present, we use it as the link name
1309             let stem = sess.opts
1310                            .crate_name
1311                            .clone()
1312                            .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
1313                            .unwrap_or(input.filestem());
1314
1315             OutputFilenames {
1316                 out_directory: dirpath,
1317                 out_filestem: stem,
1318                 single_output_file: None,
1319                 extra: sess.opts.cg.extra_filename.clone(),
1320                 outputs: sess.opts.output_types.clone(),
1321             }
1322         }
1323
1324         Some(ref out_file) => {
1325             let unnamed_output_types = sess.opts
1326                                            .output_types
1327                                            .values()
1328                                            .filter(|a| a.is_none())
1329                                            .count();
1330             let ofile = if unnamed_output_types > 1 {
1331                 sess.warn("ignoring specified output filename because multiple outputs were \
1332                            requested");
1333                 None
1334             } else {
1335                 Some(out_file.clone())
1336             };
1337             if *odir != None {
1338                 sess.warn("ignoring --out-dir flag due to -o flag.");
1339             }
1340
1341             let cur_dir = Path::new("");
1342
1343             OutputFilenames {
1344                 out_directory: out_file.parent().unwrap_or(cur_dir).to_path_buf(),
1345                 out_filestem: out_file.file_stem()
1346                                       .unwrap_or(OsStr::new(""))
1347                                       .to_str()
1348                                       .unwrap()
1349                                       .to_string(),
1350                 single_output_file: ofile,
1351                 extra: sess.opts.cg.extra_filename.clone(),
1352                 outputs: sess.opts.output_types.clone(),
1353             }
1354         }
1355     }
1356 }