src/librustc/session/mod.rs

   1 // Copyright 2012-2013 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 pub use self::code_stats::{CodeStats, DataTypeKind, FieldInfo};
  12 pub use self::code_stats::{SizeKind, TypeSizeInfo, VariantInfo};
  13
  14 use dep_graph::DepGraph;
  15 use hir::def_id::{CrateNum, DefIndex};
  16
  17 use lint;
  18 use middle::cstore::CrateStore;
  19 use middle::dependency_format;
  20 use session::search_paths::PathKind;
  21 use session::config::DebugInfoLevel;
  22 use ty::tls;
  23 use util::nodemap::{FxHashMap, FxHashSet};
  24 use util::common::duration_to_secs_str;
  25
  26 use syntax::ast::NodeId;
  27 use errors::{self, DiagnosticBuilder};
  28 use errors::emitter::{Emitter, EmitterWriter};
  29 use syntax::json::JsonEmitter;
  30 use syntax::feature_gate;
  31 use syntax::parse;
  32 use syntax::parse::ParseSess;
  33 use syntax::symbol::Symbol;
  34 use syntax::{ast, codemap};
  35 use syntax::feature_gate::AttributeType;
  36 use syntax_pos::{Span, MultiSpan};
  37
  38 use rustc_back::{LinkerFlavor, PanicStrategy};
  39 use rustc_back::target::Target;
  40 use rustc_data_structures::flock;
  41 use jobserver::Client;
  42
  43 use std::cell::{self, Cell, RefCell};
  44 use std::collections::HashMap;
  45 use std::env;
  46 use std::fmt;
  47 use std::io::Write;
  48 use std::path::{Path, PathBuf};
  49 use std::rc::Rc;
  50 use std::sync::{Once, ONCE_INIT};
  51 use std::time::Duration;
  52
  53 mod code_stats;
  54 pub mod config;
  55 pub mod filesearch;
  56 pub mod search_paths;
  57
  58 // Represents the data associated with a compilation
  59 // session for a single crate.
  60 pub struct Session {
  61     pub dep_graph: DepGraph,
  62     pub target: config::Config,
  63     pub host: Target,
  64     pub opts: config::Options,
  65     pub cstore: Rc<CrateStore>,
  66     pub parse_sess: ParseSess,
  67     // For a library crate, this is always none
  68     pub entry_fn: RefCell<Option<(NodeId, Span)>>,
  69     pub entry_type: Cell<Option<config::EntryFnType>>,
  70     pub plugin_registrar_fn: Cell<Option<ast::NodeId>>,
  71     pub derive_registrar_fn: Cell<Option<ast::NodeId>>,
  72     pub default_sysroot: Option<PathBuf>,
  73     // The name of the root source file of the crate, in the local file system.
  74     // The path is always expected to be absolute. `None` means that there is no
  75     // source file.
  76     pub local_crate_source_file: Option<String>,
  77     // The directory the compiler has been executed in plus a flag indicating
  78     // if the value stored here has been affected by path remapping.
  79     pub working_dir: (String, bool),
  80     pub lint_store: RefCell<lint::LintStore>,
  81     pub lints: RefCell<lint::LintTable>,
  82     /// Set of (LintId, span, message) tuples tracking lint (sub)diagnostics
  83     /// that have been set once, but should not be set again, in order to avoid
  84     /// redundantly verbose output (Issue #24690).
  85     pub one_time_diagnostics: RefCell<FxHashSet<(lint::LintId, Span, String)>>,
  86     pub plugin_llvm_passes: RefCell<Vec<String>>,
  87     pub plugin_attributes: RefCell<Vec<(String, AttributeType)>>,
  88     pub crate_types: RefCell<Vec<config::CrateType>>,
  89     pub dependency_formats: RefCell<dependency_format::Dependencies>,
  90     // The crate_disambiguator is constructed out of all the `-C metadata`
  91     // arguments passed to the compiler. Its value together with the crate-name
  92     // forms a unique global identifier for the crate. It is used to allow
  93     // multiple crates with the same name to coexist. See the
  94     // trans::back::symbol_names module for more information.
  95     pub crate_disambiguator: RefCell<Symbol>,
  96     pub features: RefCell<feature_gate::Features>,
  97
  98     /// The maximum recursion limit for potentially infinitely recursive
  99     /// operations such as auto-dereference and monomorphization.
 100     pub recursion_limit: Cell<usize>,
 101
 102     /// The maximum length of types during monomorphization.
 103     pub type_length_limit: Cell<usize>,
 104
 105     /// The metadata::creader module may inject an allocator/panic_runtime
 106     /// dependency if it didn't already find one, and this tracks what was
 107     /// injected.
 108     pub injected_allocator: Cell<Option<CrateNum>>,
 109     pub injected_panic_runtime: Cell<Option<CrateNum>>,
 110
 111     /// Map from imported macro spans (which consist of
 112     /// the localized span for the macro body) to the
 113     /// macro name and defintion span in the source crate.
 114     pub imported_macro_spans: RefCell<HashMap<Span, (String, Span)>>,
 115
 116     incr_comp_session: RefCell<IncrCompSession>,
 117
 118     /// Some measurements that are being gathered during compilation.
 119     pub perf_stats: PerfStats,
 120
 121     /// Data about code being compiled, gathered during compilation.
 122     pub code_stats: RefCell<CodeStats>,
 123
 124     next_node_id: Cell<ast::NodeId>,
 125
 126     /// If -zfuel=crate=n is specified, Some(crate).
 127     optimization_fuel_crate: Option<String>,
 128     /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0.
 129     optimization_fuel_limit: Cell<u64>,
 130     /// We're rejecting all further optimizations.
 131     out_of_fuel: Cell<bool>,
 132
 133     // The next two are public because the driver needs to read them.
 134
 135     /// If -zprint-fuel=crate, Some(crate).
 136     pub print_fuel_crate: Option<String>,
 137     /// Always set to zero and incremented so that we can print fuel expended by a crate.
 138     pub print_fuel: Cell<u64>,
 139
 140     /// Loaded up early on in the initialization of this `Session` to avoid
 141     /// false positives about a job server in our environment.
 142     pub jobserver_from_env: Option<Client>,
 143 }
 144
 145 pub struct PerfStats {
 146     // The accumulated time needed for computing the SVH of the crate
 147     pub svh_time: Cell<Duration>,
 148     // The accumulated time spent on computing incr. comp. hashes
 149     pub incr_comp_hashes_time: Cell<Duration>,
 150     // The number of incr. comp. hash computations performed
 151     pub incr_comp_hashes_count: Cell<u64>,
 152     // The number of bytes hashed when computing ICH values
 153     pub incr_comp_bytes_hashed: Cell<u64>,
 154     // The accumulated time spent on computing symbol hashes
 155     pub symbol_hash_time: Cell<Duration>,
 156     // The accumulated time spent decoding def path tables from metadata
 157     pub decode_def_path_tables_time: Cell<Duration>,
 158 }
 159
 160 impl Session {
 161     pub fn local_crate_disambiguator(&self) -> Symbol {
 162         *self.crate_disambiguator.borrow()
 163     }
 164     pub fn struct_span_warn<'a, S: Into<MultiSpan>>(&'a self,
 165                                                     sp: S,
 166                                                     msg: &str)
 167                                                     -> DiagnosticBuilder<'a> {
 168         self.diagnostic().struct_span_warn(sp, msg)
 169     }
 170     pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(&'a self,
 171                                                               sp: S,
 172                                                               msg: &str,
 173                                                               code: &str)
 174                                                               -> DiagnosticBuilder<'a> {
 175         self.diagnostic().struct_span_warn_with_code(sp, msg, code)
 176     }
 177     pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a>  {
 178         self.diagnostic().struct_warn(msg)
 179     }
 180     pub fn struct_span_err<'a, S: Into<MultiSpan>>(&'a self,
 181                                                    sp: S,
 182                                                    msg: &str)
 183                                                    -> DiagnosticBuilder<'a> {
 184         self.diagnostic().struct_span_err(sp, msg)
 185     }
 186     pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(&'a self,
 187                                                              sp: S,
 188                                                              msg: &str,
 189                                                              code: &str)
 190                                                              -> DiagnosticBuilder<'a> {
 191         self.diagnostic().struct_span_err_with_code(sp, msg, code)
 192     }
 193     // FIXME: This method should be removed (every error should have an associated error code).
 194     pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
 195         self.diagnostic().struct_err(msg)
 196     }
 197     pub fn struct_err_with_code<'a>(&'a self, msg: &str, code: &str) -> DiagnosticBuilder<'a> {
 198         self.diagnostic().struct_err_with_code(msg, code)
 199     }
 200     pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(&'a self,
 201                                                      sp: S,
 202                                                      msg: &str)
 203                                                      -> DiagnosticBuilder<'a> {
 204         self.diagnostic().struct_span_fatal(sp, msg)
 205     }
 206     pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(&'a self,
 207                                                                sp: S,
 208                                                                msg: &str,
 209                                                                code: &str)
 210                                                                -> DiagnosticBuilder<'a> {
 211         self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
 212     }
 213     pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a>  {
 214         self.diagnostic().struct_fatal(msg)
 215     }
 216
 217     pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
 218         panic!(self.diagnostic().span_fatal(sp, msg))
 219     }
 220     pub fn span_fatal_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) -> ! {
 221         panic!(self.diagnostic().span_fatal_with_code(sp, msg, code))
 222     }
 223     pub fn fatal(&self, msg: &str) -> ! {
 224         panic!(self.diagnostic().fatal(msg))
 225     }
 226     pub fn span_err_or_warn<S: Into<MultiSpan>>(&self, is_warning: bool, sp: S, msg: &str) {
 227         if is_warning {
 228             self.span_warn(sp, msg);
 229         } else {
 230             self.span_err(sp, msg);
 231         }
 232     }
 233     pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 234         self.diagnostic().span_err(sp, msg)
 235     }
 236     pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) {
 237         self.diagnostic().span_err_with_code(sp, &msg, code)
 238     }
 239     pub fn err(&self, msg: &str) {
 240         self.diagnostic().err(msg)
 241     }
 242     pub fn err_count(&self) -> usize {
 243         self.diagnostic().err_count()
 244     }
 245     pub fn has_errors(&self) -> bool {
 246         self.diagnostic().has_errors()
 247     }
 248     pub fn abort_if_errors(&self) {
 249         self.diagnostic().abort_if_errors();
 250     }
 251     pub fn track_errors<F, T>(&self, f: F) -> Result<T, usize>
 252         where F: FnOnce() -> T
 253     {
 254         let old_count = self.err_count();
 255         let result = f();
 256         let errors = self.err_count() - old_count;
 257         if errors == 0 {
 258             Ok(result)
 259         } else {
 260             Err(errors)
 261         }
 262     }
 263     pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 264         self.diagnostic().span_warn(sp, msg)
 265     }
 266     pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) {
 267         self.diagnostic().span_warn_with_code(sp, msg, code)
 268     }
 269     pub fn warn(&self, msg: &str) {
 270         self.diagnostic().warn(msg)
 271     }
 272     pub fn opt_span_warn<S: Into<MultiSpan>>(&self, opt_sp: Option<S>, msg: &str) {
 273         match opt_sp {
 274             Some(sp) => self.span_warn(sp, msg),
 275             None => self.warn(msg),
 276         }
 277     }
 278     /// Delay a span_bug() call until abort_if_errors()
 279     pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 280         self.diagnostic().delay_span_bug(sp, msg)
 281     }
 282     pub fn note_without_error(&self, msg: &str) {
 283         self.diagnostic().note_without_error(msg)
 284     }
 285     pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 286         self.diagnostic().span_note_without_error(sp, msg)
 287     }
 288     pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
 289         self.diagnostic().span_unimpl(sp, msg)
 290     }
 291     pub fn unimpl(&self, msg: &str) -> ! {
 292         self.diagnostic().unimpl(msg)
 293     }
 294
 295     pub fn add_lint<S: Into<MultiSpan>>(&self,
 296                                         lint: &'static lint::Lint,
 297                                         id: ast::NodeId,
 298                                         sp: S,
 299                                         msg: String)
 300     {
 301         self.lints.borrow_mut().add_lint(lint, id, sp, msg);
 302     }
 303
 304     pub fn add_lint_diagnostic<M>(&self,
 305                                   lint: &'static lint::Lint,
 306                                   id: ast::NodeId,
 307                                   msg: M)
 308         where M: lint::IntoEarlyLint,
 309     {
 310         self.lints.borrow_mut().add_lint_diagnostic(lint, id, msg);
 311     }
 312
 313     pub fn reserve_node_ids(&self, count: usize) -> ast::NodeId {
 314         let id = self.next_node_id.get();
 315
 316         match id.as_usize().checked_add(count) {
 317             Some(next) => {
 318                 self.next_node_id.set(ast::NodeId::new(next));
 319             }
 320             None => bug!("Input too large, ran out of node ids!")
 321         }
 322
 323         id
 324     }
 325     pub fn next_node_id(&self) -> NodeId {
 326         self.reserve_node_ids(1)
 327     }
 328     pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler {
 329         &self.parse_sess.span_diagnostic
 330     }
 331
 332     /// Analogous to calling `.span_note` on the given DiagnosticBuilder, but
 333     /// deduplicates on lint ID, span, and message for this `Session` if we're
 334     /// not outputting in JSON mode.
 335     //
 336     // FIXME: if the need arises for one-time diagnostics other than
 337     // `span_note`, we almost certainly want to generalize this
 338     // "check/insert-into the one-time diagnostics map, then set message if
 339     // it's not already there" code to accomodate all of them
 340     pub fn diag_span_note_once<'a, 'b>(&'a self,
 341                                        diag_builder: &'b mut DiagnosticBuilder<'a>,
 342                                        lint: &'static lint::Lint, span: Span, message: &str) {
 343         match self.opts.error_format {
 344             // when outputting JSON for tool consumption, the tool might want
 345             // the duplicates
 346             config::ErrorOutputType::Json => {
 347                 diag_builder.span_note(span, &message);
 348             },
 349             _ => {
 350                 let lint_id = lint::LintId::of(lint);
 351                 let id_span_message = (lint_id, span, message.to_owned());
 352                 let fresh = self.one_time_diagnostics.borrow_mut().insert(id_span_message);
 353                 if fresh {
 354                     diag_builder.span_note(span, &message);
 355                 }
 356             }
 357         }
 358     }
 359
 360     pub fn codemap<'a>(&'a self) -> &'a codemap::CodeMap {
 361         self.parse_sess.codemap()
 362     }
 363     pub fn verbose(&self) -> bool { self.opts.debugging_opts.verbose }
 364     pub fn time_passes(&self) -> bool { self.opts.debugging_opts.time_passes }
 365     pub fn count_llvm_insns(&self) -> bool {
 366         self.opts.debugging_opts.count_llvm_insns
 367     }
 368     pub fn time_llvm_passes(&self) -> bool {
 369         self.opts.debugging_opts.time_llvm_passes
 370     }
 371     pub fn trans_stats(&self) -> bool { self.opts.debugging_opts.trans_stats }
 372     pub fn meta_stats(&self) -> bool { self.opts.debugging_opts.meta_stats }
 373     pub fn asm_comments(&self) -> bool { self.opts.debugging_opts.asm_comments }
 374     pub fn no_verify(&self) -> bool { self.opts.debugging_opts.no_verify }
 375     pub fn borrowck_stats(&self) -> bool { self.opts.debugging_opts.borrowck_stats }
 376     pub fn print_llvm_passes(&self) -> bool {
 377         self.opts.debugging_opts.print_llvm_passes
 378     }
 379     pub fn lto(&self) -> bool {
 380         self.opts.cg.lto
 381     }
 382     /// Returns the panic strategy for this compile session. If the user explicitly selected one
 383     /// using '-C panic', use that, otherwise use the panic strategy defined by the target.
 384     pub fn panic_strategy(&self) -> PanicStrategy {
 385         self.opts.cg.panic.unwrap_or(self.target.target.options.panic_strategy)
 386     }
 387     pub fn linker_flavor(&self) -> LinkerFlavor {
 388         self.opts.debugging_opts.linker_flavor.unwrap_or(self.target.target.linker_flavor)
 389     }
 390     pub fn no_landing_pads(&self) -> bool {
 391         self.opts.debugging_opts.no_landing_pads || self.panic_strategy() == PanicStrategy::Abort
 392     }
 393     pub fn unstable_options(&self) -> bool {
 394         self.opts.debugging_opts.unstable_options
 395     }
 396     pub fn nonzeroing_move_hints(&self) -> bool {
 397         self.opts.debugging_opts.enable_nonzeroing_move_hints
 398     }
 399     pub fn overflow_checks(&self) -> bool {
 400         self.opts.cg.overflow_checks
 401             .or(self.opts.debugging_opts.force_overflow_checks)
 402             .unwrap_or(self.opts.debug_assertions)
 403     }
 404
 405     pub fn must_not_eliminate_frame_pointers(&self) -> bool {
 406         self.opts.debuginfo != DebugInfoLevel::NoDebugInfo ||
 407         !self.target.target.options.eliminate_frame_pointer
 408     }
 409
 410     /// Returns the symbol name for the registrar function,
 411     /// given the crate Svh and the function DefIndex.
 412     pub fn generate_plugin_registrar_symbol(&self, disambiguator: Symbol, index: DefIndex)
 413                                             -> String {
 414         format!("__rustc_plugin_registrar__{}_{}", disambiguator, index.as_usize())
 415     }
 416
 417     pub fn generate_derive_registrar_symbol(&self, disambiguator: Symbol, index: DefIndex)
 418                                             -> String {
 419         format!("__rustc_derive_registrar__{}_{}", disambiguator, index.as_usize())
 420     }
 421
 422     pub fn sysroot<'a>(&'a self) -> &'a Path {
 423         match self.opts.maybe_sysroot {
 424             Some (ref sysroot) => sysroot,
 425             None => self.default_sysroot.as_ref()
 426                         .expect("missing sysroot and default_sysroot in Session")
 427         }
 428     }
 429     pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch {
 430         filesearch::FileSearch::new(self.sysroot(),
 431                                     &self.opts.target_triple,
 432                                     &self.opts.search_paths,
 433                                     kind)
 434     }
 435     pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch {
 436         filesearch::FileSearch::new(
 437             self.sysroot(),
 438             config::host_triple(),
 439             &self.opts.search_paths,
 440             kind)
 441     }
 442
 443     pub fn init_incr_comp_session(&self,
 444                                   session_dir: PathBuf,
 445                                   lock_file: flock::Lock) {
 446         let mut incr_comp_session = self.incr_comp_session.borrow_mut();
 447
 448         if let IncrCompSession::NotInitialized = *incr_comp_session { } else {
 449             bug!("Trying to initialize IncrCompSession `{:?}`", *incr_comp_session)
 450         }
 451
 452         *incr_comp_session = IncrCompSession::Active {
 453             session_directory: session_dir,
 454             lock_file: lock_file,
 455         };
 456     }
 457
 458     pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) {
 459         let mut incr_comp_session = self.incr_comp_session.borrow_mut();
 460
 461         if let IncrCompSession::Active { .. } = *incr_comp_session { } else {
 462             bug!("Trying to finalize IncrCompSession `{:?}`", *incr_comp_session)
 463         }
 464
 465         // Note: This will also drop the lock file, thus unlocking the directory
 466         *incr_comp_session = IncrCompSession::Finalized {
 467             session_directory: new_directory_path,
 468         };
 469     }
 470
 471     pub fn mark_incr_comp_session_as_invalid(&self) {
 472         let mut incr_comp_session = self.incr_comp_session.borrow_mut();
 473
 474         let session_directory = match *incr_comp_session {
 475             IncrCompSession::Active { ref session_directory, .. } => {
 476                 session_directory.clone()
 477             }
 478             _ => bug!("Trying to invalidate IncrCompSession `{:?}`",
 479                       *incr_comp_session),
 480         };
 481
 482         // Note: This will also drop the lock file, thus unlocking the directory
 483         *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors {
 484             session_directory: session_directory
 485         };
 486     }
 487
 488     pub fn incr_comp_session_dir(&self) -> cell::Ref<PathBuf> {
 489         let incr_comp_session = self.incr_comp_session.borrow();
 490         cell::Ref::map(incr_comp_session, |incr_comp_session| {
 491             match *incr_comp_session {
 492                 IncrCompSession::NotInitialized => {
 493                     bug!("Trying to get session directory from IncrCompSession `{:?}`",
 494                         *incr_comp_session)
 495                 }
 496                 IncrCompSession::Active { ref session_directory, .. } |
 497                 IncrCompSession::Finalized { ref session_directory } |
 498                 IncrCompSession::InvalidBecauseOfErrors { ref session_directory } => {
 499                     session_directory
 500                 }
 501             }
 502         })
 503     }
 504
 505     pub fn incr_comp_session_dir_opt(&self) -> Option<cell::Ref<PathBuf>> {
 506         if self.opts.incremental.is_some() {
 507             Some(self.incr_comp_session_dir())
 508         } else {
 509             None
 510         }
 511     }
 512
 513     pub fn print_perf_stats(&self) {
 514         println!("Total time spent computing SVHs:               {}",
 515                  duration_to_secs_str(self.perf_stats.svh_time.get()));
 516         println!("Total time spent computing incr. comp. hashes: {}",
 517                  duration_to_secs_str(self.perf_stats.incr_comp_hashes_time.get()));
 518         println!("Total number of incr. comp. hashes computed:   {}",
 519                  self.perf_stats.incr_comp_hashes_count.get());
 520         println!("Total number of bytes hashed for incr. comp.:  {}",
 521                  self.perf_stats.incr_comp_bytes_hashed.get());
 522         println!("Average bytes hashed per incr. comp. HIR node: {}",
 523                  self.perf_stats.incr_comp_bytes_hashed.get() /
 524                  self.perf_stats.incr_comp_hashes_count.get());
 525         println!("Total time spent computing symbol hashes:      {}",
 526                  duration_to_secs_str(self.perf_stats.symbol_hash_time.get()));
 527         println!("Total time spent decoding DefPath tables:      {}",
 528                  duration_to_secs_str(self.perf_stats.decode_def_path_tables_time.get()));
 529     }
 530
 531     /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
 532     /// This expends fuel if applicable, and records fuel if applicable.
 533     pub fn consider_optimizing<T: Fn() -> String>(&self, crate_name: &str, msg: T) -> bool {
 534         let mut ret = true;
 535         match self.optimization_fuel_crate {
 536             Some(ref c) if c == crate_name => {
 537                 let fuel = self.optimization_fuel_limit.get();
 538                 ret = fuel != 0;
 539                 if fuel == 0 && !self.out_of_fuel.get() {
 540                     println!("optimization-fuel-exhausted: {}", msg());
 541                     self.out_of_fuel.set(true);
 542                 } else if fuel > 0 {
 543                     self.optimization_fuel_limit.set(fuel-1);
 544                 }
 545             }
 546             _ => {}
 547         }
 548         match self.print_fuel_crate {
 549             Some(ref c) if c == crate_name=> {
 550                 self.print_fuel.set(self.print_fuel.get()+1);
 551             },
 552             _ => {}
 553         }
 554         ret
 555     }
 556 }
 557
 558 pub fn build_session(sopts: config::Options,
 559                      dep_graph: &DepGraph,
 560                      local_crate_source_file: Option<PathBuf>,
 561                      registry: errors::registry::Registry,
 562                      cstore: Rc<CrateStore>)
 563                      -> Session {
 564     let file_path_mapping = sopts.file_path_mapping();
 565
 566     build_session_with_codemap(sopts,
 567                                dep_graph,
 568                                local_crate_source_file,
 569                                registry,
 570                                cstore,
 571                                Rc::new(codemap::CodeMap::new(file_path_mapping)),
 572                                None)
 573 }
 574
 575 pub fn build_session_with_codemap(sopts: config::Options,
 576                                   dep_graph: &DepGraph,
 577                                   local_crate_source_file: Option<PathBuf>,
 578                                   registry: errors::registry::Registry,
 579                                   cstore: Rc<CrateStore>,
 580                                   codemap: Rc<codemap::CodeMap>,
 581                                   emitter_dest: Option<Box<Write + Send>>)
 582                                   -> Session {
 583     // FIXME: This is not general enough to make the warning lint completely override
 584     // normal diagnostic warnings, since the warning lint can also be denied and changed
 585     // later via the source code.
 586     let can_print_warnings = sopts.lint_opts
 587         .iter()
 588         .filter(|&&(ref key, _)| *key == "warnings")
 589         .map(|&(_, ref level)| *level != lint::Allow)
 590         .last()
 591         .unwrap_or(true);
 592     let treat_err_as_bug = sopts.debugging_opts.treat_err_as_bug;
 593
 594     let emitter: Box<Emitter> = match (sopts.error_format, emitter_dest) {
 595         (config::ErrorOutputType::HumanReadable(color_config), None) => {
 596             Box::new(EmitterWriter::stderr(color_config,
 597                                            Some(codemap.clone())))
 598         }
 599         (config::ErrorOutputType::HumanReadable(_), Some(dst)) => {
 600             Box::new(EmitterWriter::new(dst,
 601                                         Some(codemap.clone())))
 602         }
 603         (config::ErrorOutputType::Json, None) => {
 604             Box::new(JsonEmitter::stderr(Some(registry), codemap.clone()))
 605         }
 606         (config::ErrorOutputType::Json, Some(dst)) => {
 607             Box::new(JsonEmitter::new(dst, Some(registry), codemap.clone()))
 608         }
 609     };
 610
 611     let diagnostic_handler =
 612         errors::Handler::with_emitter(can_print_warnings,
 613                                       treat_err_as_bug,
 614                                       emitter);
 615
 616     build_session_(sopts,
 617                    dep_graph,
 618                    local_crate_source_file,
 619                    diagnostic_handler,
 620                    codemap,
 621                    cstore)
 622 }
 623
 624 pub fn build_session_(sopts: config::Options,
 625                       dep_graph: &DepGraph,
 626                       local_crate_source_file: Option<PathBuf>,
 627                       span_diagnostic: errors::Handler,
 628                       codemap: Rc<codemap::CodeMap>,
 629                       cstore: Rc<CrateStore>)
 630                       -> Session {
 631     let host = match Target::search(config::host_triple()) {
 632         Ok(t) => t,
 633         Err(e) => {
 634             panic!(span_diagnostic.fatal(&format!("Error loading host specification: {}", e)));
 635         }
 636     };
 637     let target_cfg = config::build_target_config(&sopts, &span_diagnostic);
 638
 639     let p_s = parse::ParseSess::with_span_handler(span_diagnostic, codemap);
 640     let default_sysroot = match sopts.maybe_sysroot {
 641         Some(_) => None,
 642         None => Some(filesearch::get_or_default_sysroot())
 643     };
 644
 645     let file_path_mapping = sopts.file_path_mapping();
 646
 647     // Make the path absolute, if necessary
 648     let local_crate_source_file = local_crate_source_file.map(|path| {
 649         file_path_mapping.map_prefix(path.to_string_lossy().into_owned()).0
 650     });
 651
 652     let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone());
 653     let optimization_fuel_limit = Cell::new(sopts.debugging_opts.fuel.as_ref()
 654         .map(|i| i.1).unwrap_or(0));
 655     let print_fuel_crate = sopts.debugging_opts.print_fuel.clone();
 656     let print_fuel = Cell::new(0);
 657
 658     let working_dir = env::current_dir().unwrap().to_string_lossy().into_owned();
 659     let working_dir = file_path_mapping.map_prefix(working_dir);
 660
 661     let sess = Session {
 662         dep_graph: dep_graph.clone(),
 663         target: target_cfg,
 664         host: host,
 665         opts: sopts,
 666         cstore: cstore,
 667         parse_sess: p_s,
 668         // For a library crate, this is always none
 669         entry_fn: RefCell::new(None),
 670         entry_type: Cell::new(None),
 671         plugin_registrar_fn: Cell::new(None),
 672         derive_registrar_fn: Cell::new(None),
 673         default_sysroot: default_sysroot,
 674         local_crate_source_file: local_crate_source_file,
 675         working_dir: working_dir,
 676         lint_store: RefCell::new(lint::LintStore::new()),
 677         lints: RefCell::new(lint::LintTable::new()),
 678         one_time_diagnostics: RefCell::new(FxHashSet()),
 679         plugin_llvm_passes: RefCell::new(Vec::new()),
 680         plugin_attributes: RefCell::new(Vec::new()),
 681         crate_types: RefCell::new(Vec::new()),
 682         dependency_formats: RefCell::new(FxHashMap()),
 683         crate_disambiguator: RefCell::new(Symbol::intern("")),
 684         features: RefCell::new(feature_gate::Features::new()),
 685         recursion_limit: Cell::new(64),
 686         type_length_limit: Cell::new(1048576),
 687         next_node_id: Cell::new(NodeId::new(1)),
 688         injected_allocator: Cell::new(None),
 689         injected_panic_runtime: Cell::new(None),
 690         imported_macro_spans: RefCell::new(HashMap::new()),
 691         incr_comp_session: RefCell::new(IncrCompSession::NotInitialized),
 692         perf_stats: PerfStats {
 693             svh_time: Cell::new(Duration::from_secs(0)),
 694             incr_comp_hashes_time: Cell::new(Duration::from_secs(0)),
 695             incr_comp_hashes_count: Cell::new(0),
 696             incr_comp_bytes_hashed: Cell::new(0),
 697             symbol_hash_time: Cell::new(Duration::from_secs(0)),
 698             decode_def_path_tables_time: Cell::new(Duration::from_secs(0)),
 699         },
 700         code_stats: RefCell::new(CodeStats::new()),
 701         optimization_fuel_crate: optimization_fuel_crate,
 702         optimization_fuel_limit: optimization_fuel_limit,
 703         print_fuel_crate: print_fuel_crate,
 704         print_fuel: print_fuel,
 705         out_of_fuel: Cell::new(false),
 706
 707         // Note that this is unsafe because it may misinterpret file descriptors
 708         // on Unix as jobserver file descriptors. We hopefully execute this near
 709         // the beginning of the process though to ensure we don't get false
 710         // positives, or in other words we try to execute this before we open
 711         // any file descriptors ourselves.
 712         //
 713         // Also note that we stick this in a global because there could be
 714         // multiple `Session` instances in this process, and the jobserver is
 715         // per-process.
 716         jobserver_from_env: unsafe {
 717             static mut GLOBAL_JOBSERVER: *mut Option<Client> = 0 as *mut _;
 718             static INIT: Once = ONCE_INIT;
 719             INIT.call_once(|| {
 720                 GLOBAL_JOBSERVER = Box::into_raw(Box::new(Client::from_env()));
 721             });
 722             (*GLOBAL_JOBSERVER).clone()
 723         },
 724     };
 725
 726     sess
 727 }
 728
 729 /// Holds data on the current incremental compilation session, if there is one.
 730 #[derive(Debug)]
 731 pub enum IncrCompSession {
 732     // This is the state the session will be in until the incr. comp. dir is
 733     // needed.
 734     NotInitialized,
 735     // This is the state during which the session directory is private and can
 736     // be modified.
 737     Active {
 738         session_directory: PathBuf,
 739         lock_file: flock::Lock,
 740     },
 741     // This is the state after the session directory has been finalized. In this
 742     // state, the contents of the directory must not be modified any more.
 743     Finalized {
 744         session_directory: PathBuf,
 745     },
 746     // This is an error state that is reached when some compilation error has
 747     // occurred. It indicates that the contents of the session directory must
 748     // not be used, since they might be invalid.
 749     InvalidBecauseOfErrors {
 750         session_directory: PathBuf,
 751     }
 752 }
 753
 754 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
 755     let emitter: Box<Emitter> = match output {
 756         config::ErrorOutputType::HumanReadable(color_config) => {
 757             Box::new(EmitterWriter::stderr(color_config,
 758                                            None))
 759         }
 760         config::ErrorOutputType::Json => Box::new(JsonEmitter::basic()),
 761     };
 762     let handler = errors::Handler::with_emitter(true, false, emitter);
 763     handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal);
 764     panic!(errors::FatalError);
 765 }
 766
 767 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
 768     let emitter: Box<Emitter> = match output {
 769         config::ErrorOutputType::HumanReadable(color_config) => {
 770             Box::new(EmitterWriter::stderr(color_config,
 771                                            None))
 772         }
 773         config::ErrorOutputType::Json => Box::new(JsonEmitter::basic()),
 774     };
 775     let handler = errors::Handler::with_emitter(true, false, emitter);
 776     handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
 777 }
 778
 779 // Err(0) means compilation was stopped, but no errors were found.
 780 // This would be better as a dedicated enum, but using try! is so convenient.
 781 pub type CompileResult = Result<(), usize>;
 782
 783 pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
 784     if err_count == 0 {
 785         Ok(())
 786     } else {
 787         Err(err_count)
 788     }
 789 }
 790
 791 #[cold]
 792 #[inline(never)]
 793 pub fn bug_fmt(file: &'static str, line: u32, args: fmt::Arguments) -> ! {
 794     // this wrapper mostly exists so I don't have to write a fully
 795     // qualified path of None::<Span> inside the bug!() macro defintion
 796     opt_span_bug_fmt(file, line, None::<Span>, args);
 797 }
 798
 799 #[cold]
 800 #[inline(never)]
 801 pub fn span_bug_fmt<S: Into<MultiSpan>>(file: &'static str,
 802                                         line: u32,
 803                                         span: S,
 804                                         args: fmt::Arguments) -> ! {
 805     opt_span_bug_fmt(file, line, Some(span), args);
 806 }
 807
 808 fn opt_span_bug_fmt<S: Into<MultiSpan>>(file: &'static str,
 809                                         line: u32,
 810                                         span: Option<S>,
 811                                         args: fmt::Arguments) -> ! {
 812     tls::with_opt(move |tcx| {
 813         let msg = format!("{}:{}: {}", file, line, args);
 814         match (tcx, span) {
 815             (Some(tcx), Some(span)) => tcx.sess.diagnostic().span_bug(span, &msg),
 816             (Some(tcx), None) => tcx.sess.diagnostic().bug(&msg),
 817             (None, _) => panic!(msg)
 818         }
 819     });
 820     unreachable!();
 821 }