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, DepNode};
  15 use hir::def_id::{DefId, CrateNum, DefIndex, CRATE_DEF_INDEX};
  16 use lint;
  17 use middle::cstore::CrateStore;
  18 use middle::dependency_format;
  19 use session::search_paths::PathKind;
  20 use session::config::DebugInfoLevel;
  21 use ty::tls;
  22 use util::nodemap::{FxHashMap, FxHashSet};
  23 use util::common::duration_to_secs_str;
  24
  25 use syntax::ast::NodeId;
  26 use errors::{self, DiagnosticBuilder};
  27 use errors::emitter::{Emitter, EmitterWriter};
  28 use syntax::json::JsonEmitter;
  29 use syntax::feature_gate;
  30 use syntax::parse;
  31 use syntax::parse::ParseSess;
  32 use syntax::symbol::Symbol;
  33 use syntax::{ast, codemap};
  34 use syntax::feature_gate::AttributeType;
  35 use syntax_pos::{Span, MultiSpan, FileMap};
  36
  37 use rustc_back::{LinkerFlavor, PanicStrategy};
  38 use rustc_back::target::Target;
  39 use rustc_data_structures::flock;
  40 use llvm;
  41
  42 use std::path::{Path, PathBuf};
  43 use std::cell::{self, Cell, RefCell};
  44 use std::collections::HashMap;
  45 use std::env;
  46 use std::ffi::CString;
  47 use std::io::Write;
  48 use std::rc::Rc;
  49 use std::fmt;
  50 use std::time::Duration;
  51 use std::sync::Arc;
  52 use libc::c_int;
  53
  54 mod code_stats;
  55 pub mod config;
  56 pub mod filesearch;
  57 pub mod search_paths;
  58
  59 // Represents the data associated with a compilation
  60 // session for a single crate.
  61 pub struct Session {
  62     pub dep_graph: DepGraph,
  63     pub target: config::Config,
  64     pub host: Target,
  65     pub opts: config::Options,
  66     pub cstore: Rc<CrateStore>,
  67     pub parse_sess: ParseSess,
  68     // For a library crate, this is always none
  69     pub entry_fn: RefCell<Option<(NodeId, Span)>>,
  70     pub entry_type: Cell<Option<config::EntryFnType>>,
  71     pub plugin_registrar_fn: Cell<Option<ast::NodeId>>,
  72     pub derive_registrar_fn: Cell<Option<ast::NodeId>>,
  73     pub default_sysroot: Option<PathBuf>,
  74     // The name of the root source file of the crate, in the local file system.
  75     // The path is always expected to be absolute. `None` means that there is no
  76     // source file.
  77     pub local_crate_source_file: Option<String>,
  78     // The directory the compiler has been executed in plus a flag indicating
  79     // if the value stored here has been affected by path remapping.
  80     pub working_dir: (String, bool),
  81     pub lint_store: RefCell<lint::LintStore>,
  82     pub lints: RefCell<lint::LintTable>,
  83     /// Set of (LintId, span, message) tuples tracking lint (sub)diagnostics
  84     /// that have been set once, but should not be set again, in order to avoid
  85     /// redundantly verbose output (Issue #24690).
  86     pub one_time_diagnostics: RefCell<FxHashSet<(lint::LintId, Span, String)>>,
  87     pub plugin_llvm_passes: RefCell<Vec<String>>,
  88     pub plugin_attributes: RefCell<Vec<(String, AttributeType)>>,
  89     pub crate_types: RefCell<Vec<config::CrateType>>,
  90     pub dependency_formats: RefCell<dependency_format::Dependencies>,
  91     // The crate_disambiguator is constructed out of all the `-C metadata`
  92     // arguments passed to the compiler. Its value together with the crate-name
  93     // forms a unique global identifier for the crate. It is used to allow
  94     // multiple crates with the same name to coexist. See the
  95     // trans::back::symbol_names module for more information.
  96     pub crate_disambiguator: RefCell<Symbol>,
  97     pub features: RefCell<feature_gate::Features>,
  98
  99     /// The maximum recursion limit for potentially infinitely recursive
 100     /// operations such as auto-dereference and monomorphization.
 101     pub recursion_limit: Cell<usize>,
 102
 103     /// The maximum length of types during monomorphization.
 104     pub type_length_limit: Cell<usize>,
 105
 106     /// The metadata::creader module may inject an allocator/panic_runtime
 107     /// dependency if it didn't already find one, and this tracks what was
 108     /// injected.
 109     pub injected_allocator: Cell<Option<CrateNum>>,
 110     pub injected_panic_runtime: Cell<Option<CrateNum>>,
 111
 112     /// Map from imported macro spans (which consist of
 113     /// the localized span for the macro body) to the
 114     /// macro name and defintion span in the source crate.
 115     pub imported_macro_spans: RefCell<HashMap<Span, (String, Span)>>,
 116
 117     incr_comp_session: RefCell<IncrCompSession>,
 118
 119     /// Some measurements that are being gathered during compilation.
 120     pub perf_stats: PerfStats,
 121
 122     /// Data about code being compiled, gathered during compilation.
 123     pub code_stats: RefCell<CodeStats>,
 124
 125     next_node_id: Cell<ast::NodeId>,
 126
 127     /// If -zfuel=crate=n is specified, Some(crate).
 128     optimization_fuel_crate: Option<String>,
 129     /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0.
 130     optimization_fuel_limit: Cell<u64>,
 131     /// We're rejecting all further optimizations.
 132     out_of_fuel: Cell<bool>,
 133
 134     // The next two are public because the driver needs to read them.
 135
 136     /// If -zprint-fuel=crate, Some(crate).
 137     pub print_fuel_crate: Option<String>,
 138     /// Always set to zero and incremented so that we can print fuel expended by a crate.
 139     pub print_fuel: Cell<u64>,
 140 }
 141
 142 pub struct PerfStats {
 143     // The accumulated time needed for computing the SVH of the crate
 144     pub svh_time: Cell<Duration>,
 145     // The accumulated time spent on computing incr. comp. hashes
 146     pub incr_comp_hashes_time: Cell<Duration>,
 147     // The number of incr. comp. hash computations performed
 148     pub incr_comp_hashes_count: Cell<u64>,
 149     // The number of bytes hashed when computing ICH values
 150     pub incr_comp_bytes_hashed: Cell<u64>,
 151     // The accumulated time spent on computing symbol hashes
 152     pub symbol_hash_time: Cell<Duration>,
 153     // The accumulated time spent decoding def path tables from metadata
 154     pub decode_def_path_tables_time: Cell<Duration>,
 155 }
 156
 157 impl Session {
 158     pub fn local_crate_disambiguator(&self) -> Symbol {
 159         *self.crate_disambiguator.borrow()
 160     }
 161     pub fn struct_span_warn<'a, S: Into<MultiSpan>>(&'a self,
 162                                                     sp: S,
 163                                                     msg: &str)
 164                                                     -> DiagnosticBuilder<'a>  {
 165         self.diagnostic().struct_span_warn(sp, msg)
 166     }
 167     pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(&'a self,
 168                                                               sp: S,
 169                                                               msg: &str,
 170                                                               code: &str)
 171                                                               -> DiagnosticBuilder<'a>  {
 172         self.diagnostic().struct_span_warn_with_code(sp, msg, code)
 173     }
 174     pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a>  {
 175         self.diagnostic().struct_warn(msg)
 176     }
 177     pub fn struct_span_err<'a, S: Into<MultiSpan>>(&'a self,
 178                                                    sp: S,
 179                                                    msg: &str)
 180                                                    -> DiagnosticBuilder<'a>  {
 181         self.diagnostic().struct_span_err(sp, msg)
 182     }
 183     pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(&'a self,
 184                                                              sp: S,
 185                                                              msg: &str,
 186                                                              code: &str)
 187                                                              -> DiagnosticBuilder<'a>  {
 188         self.diagnostic().struct_span_err_with_code(sp, msg, code)
 189     }
 190     pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a>  {
 191         self.diagnostic().struct_err(msg)
 192     }
 193     pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(&'a self,
 194                                                      sp: S,
 195                                                      msg: &str)
 196                                                      -> DiagnosticBuilder<'a>  {
 197         self.diagnostic().struct_span_fatal(sp, msg)
 198     }
 199     pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(&'a self,
 200                                                                sp: S,
 201                                                                msg: &str,
 202                                                                code: &str)
 203                                                                -> DiagnosticBuilder<'a>  {
 204         self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
 205     }
 206     pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a>  {
 207         self.diagnostic().struct_fatal(msg)
 208     }
 209
 210     pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
 211         panic!(self.diagnostic().span_fatal(sp, msg))
 212     }
 213     pub fn span_fatal_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) -> ! {
 214         panic!(self.diagnostic().span_fatal_with_code(sp, msg, code))
 215     }
 216     pub fn fatal(&self, msg: &str) -> ! {
 217         panic!(self.diagnostic().fatal(msg))
 218     }
 219     pub fn span_err_or_warn<S: Into<MultiSpan>>(&self, is_warning: bool, sp: S, msg: &str) {
 220         if is_warning {
 221             self.span_warn(sp, msg);
 222         } else {
 223             self.span_err(sp, msg);
 224         }
 225     }
 226     pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 227         self.diagnostic().span_err(sp, msg)
 228     }
 229     pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) {
 230         self.diagnostic().span_err_with_code(sp, &msg, code)
 231     }
 232     pub fn err(&self, msg: &str) {
 233         self.diagnostic().err(msg)
 234     }
 235     pub fn err_count(&self) -> usize {
 236         self.diagnostic().err_count()
 237     }
 238     pub fn has_errors(&self) -> bool {
 239         self.diagnostic().has_errors()
 240     }
 241     pub fn abort_if_errors(&self) {
 242         self.diagnostic().abort_if_errors();
 243     }
 244     pub fn track_errors<F, T>(&self, f: F) -> Result<T, usize>
 245         where F: FnOnce() -> T
 246     {
 247         let old_count = self.err_count();
 248         let result = f();
 249         let errors = self.err_count() - old_count;
 250         if errors == 0 {
 251             Ok(result)
 252         } else {
 253             Err(errors)
 254         }
 255     }
 256     pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 257         self.diagnostic().span_warn(sp, msg)
 258     }
 259     pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: &str) {
 260         self.diagnostic().span_warn_with_code(sp, msg, code)
 261     }
 262     pub fn warn(&self, msg: &str) {
 263         self.diagnostic().warn(msg)
 264     }
 265     pub fn opt_span_warn<S: Into<MultiSpan>>(&self, opt_sp: Option<S>, msg: &str) {
 266         match opt_sp {
 267             Some(sp) => self.span_warn(sp, msg),
 268             None => self.warn(msg),
 269         }
 270     }
 271     /// Delay a span_bug() call until abort_if_errors()
 272     pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 273         self.diagnostic().delay_span_bug(sp, msg)
 274     }
 275     pub fn note_without_error(&self, msg: &str) {
 276         self.diagnostic().note_without_error(msg)
 277     }
 278     pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
 279         self.diagnostic().span_note_without_error(sp, msg)
 280     }
 281     pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
 282         self.diagnostic().span_unimpl(sp, msg)
 283     }
 284     pub fn unimpl(&self, msg: &str) -> ! {
 285         self.diagnostic().unimpl(msg)
 286     }
 287
 288     pub fn add_lint<S: Into<MultiSpan>>(&self,
 289                                         lint: &'static lint::Lint,
 290                                         id: ast::NodeId,
 291                                         sp: S,
 292                                         msg: String)
 293     {
 294         self.lints.borrow_mut().add_lint(lint, id, sp, msg);
 295     }
 296
 297     pub fn add_lint_diagnostic<M>(&self,
 298                                   lint: &'static lint::Lint,
 299                                   id: ast::NodeId,
 300                                   msg: M)
 301         where M: lint::IntoEarlyLint,
 302     {
 303         self.lints.borrow_mut().add_lint_diagnostic(lint, id, msg);
 304     }
 305
 306     pub fn reserve_node_ids(&self, count: usize) -> ast::NodeId {
 307         let id = self.next_node_id.get();
 308
 309         match id.as_usize().checked_add(count) {
 310             Some(next) => {
 311                 self.next_node_id.set(ast::NodeId::new(next));
 312             }
 313             None => bug!("Input too large, ran out of node ids!")
 314         }
 315
 316         id
 317     }
 318     pub fn next_node_id(&self) -> NodeId {
 319         self.reserve_node_ids(1)
 320     }
 321     pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler {
 322         &self.parse_sess.span_diagnostic
 323     }
 324
 325     /// Analogous to calling `.span_note` on the given DiagnosticBuilder, but
 326     /// deduplicates on lint ID, span, and message for this `Session` if we're
 327     /// not outputting in JSON mode.
 328     //
 329     // FIXME: if the need arises for one-time diagnostics other than
 330     // `span_note`, we almost certainly want to generalize this
 331     // "check/insert-into the one-time diagnostics map, then set message if
 332     // it's not already there" code to accomodate all of them
 333     pub fn diag_span_note_once<'a, 'b>(&'a self,
 334                                        diag_builder: &'b mut DiagnosticBuilder<'a>,
 335                                        lint: &'static lint::Lint, span: Span, message: &str) {
 336         match self.opts.error_format {
 337             // when outputting JSON for tool consumption, the tool might want
 338             // the duplicates
 339             config::ErrorOutputType::Json => {
 340                 diag_builder.span_note(span, &message);
 341             },
 342             _ => {
 343                 let lint_id = lint::LintId::of(lint);
 344                 let id_span_message = (lint_id, span, message.to_owned());
 345                 let fresh = self.one_time_diagnostics.borrow_mut().insert(id_span_message);
 346                 if fresh {
 347                     diag_builder.span_note(span, &message);
 348                 }
 349             }
 350         }
 351     }
 352
 353     pub fn codemap<'a>(&'a self) -> &'a codemap::CodeMap {
 354         self.parse_sess.codemap()
 355     }
 356     pub fn verbose(&self) -> bool { self.opts.debugging_opts.verbose }
 357     pub fn time_passes(&self) -> bool { self.opts.debugging_opts.time_passes }
 358     pub fn count_llvm_insns(&self) -> bool {
 359         self.opts.debugging_opts.count_llvm_insns
 360     }
 361     pub fn time_llvm_passes(&self) -> bool {
 362         self.opts.debugging_opts.time_llvm_passes
 363     }
 364     pub fn trans_stats(&self) -> bool { self.opts.debugging_opts.trans_stats }
 365     pub fn meta_stats(&self) -> bool { self.opts.debugging_opts.meta_stats }
 366     pub fn asm_comments(&self) -> bool { self.opts.debugging_opts.asm_comments }
 367     pub fn no_verify(&self) -> bool { self.opts.debugging_opts.no_verify }
 368     pub fn borrowck_stats(&self) -> bool { self.opts.debugging_opts.borrowck_stats }
 369     pub fn print_llvm_passes(&self) -> bool {
 370         self.opts.debugging_opts.print_llvm_passes
 371     }
 372     pub fn lto(&self) -> bool {
 373         self.opts.cg.lto
 374     }
 375     /// Returns the panic strategy for this compile session. If the user explicitly selected one
 376     /// using '-C panic', use that, otherwise use the panic strategy defined by the target.
 377     pub fn panic_strategy(&self) -> PanicStrategy {
 378         self.opts.cg.panic.unwrap_or(self.target.target.options.panic_strategy)
 379     }
 380     pub fn linker_flavor(&self) -> LinkerFlavor {
 381         self.opts.debugging_opts.linker_flavor.unwrap_or(self.target.target.linker_flavor)
 382     }
 383     pub fn no_landing_pads(&self) -> bool {
 384         self.opts.debugging_opts.no_landing_pads || self.panic_strategy() == PanicStrategy::Abort
 385     }
 386     pub fn unstable_options(&self) -> bool {
 387         self.opts.debugging_opts.unstable_options
 388     }
 389     pub fn nonzeroing_move_hints(&self) -> bool {
 390         self.opts.debugging_opts.enable_nonzeroing_move_hints
 391     }
 392     pub fn overflow_checks(&self) -> bool {
 393         self.opts.cg.overflow_checks
 394             .or(self.opts.debugging_opts.force_overflow_checks)
 395             .unwrap_or(self.opts.debug_assertions)
 396     }
 397
 398     pub fn must_not_eliminate_frame_pointers(&self) -> bool {
 399         self.opts.debuginfo != DebugInfoLevel::NoDebugInfo ||
 400         !self.target.target.options.eliminate_frame_pointer
 401     }
 402
 403     /// Returns the symbol name for the registrar function,
 404     /// given the crate Svh and the function DefIndex.
 405     pub fn generate_plugin_registrar_symbol(&self, disambiguator: Symbol, index: DefIndex)
 406                                             -> String {
 407         format!("__rustc_plugin_registrar__{}_{}", disambiguator, index.as_usize())
 408     }
 409
 410     pub fn generate_derive_registrar_symbol(&self, disambiguator: Symbol, index: DefIndex)
 411                                             -> String {
 412         format!("__rustc_derive_registrar__{}_{}", disambiguator, index.as_usize())
 413     }
 414
 415     pub fn sysroot<'a>(&'a self) -> &'a Path {
 416         match self.opts.maybe_sysroot {
 417             Some (ref sysroot) => sysroot,
 418             None => self.default_sysroot.as_ref()
 419                         .expect("missing sysroot and default_sysroot in Session")
 420         }
 421     }
 422     pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch {
 423         filesearch::FileSearch::new(self.sysroot(),
 424                                     &self.opts.target_triple,
 425                                     &self.opts.search_paths,
 426                                     kind)
 427     }
 428     pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch {
 429         filesearch::FileSearch::new(
 430             self.sysroot(),
 431             config::host_triple(),
 432             &self.opts.search_paths,
 433             kind)
 434     }
 435
 436     pub fn init_incr_comp_session(&self,
 437                                   session_dir: PathBuf,
 438                                   lock_file: flock::Lock) {
 439         let mut incr_comp_session = self.incr_comp_session.borrow_mut();
 440
 441         if let IncrCompSession::NotInitialized = *incr_comp_session { } else {
 442             bug!("Trying to initialize IncrCompSession `{:?}`", *incr_comp_session)
 443         }
 444
 445         *incr_comp_session = IncrCompSession::Active {
 446             session_directory: session_dir,
 447             lock_file: lock_file,
 448         };
 449     }
 450
 451     pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) {
 452         let mut incr_comp_session = self.incr_comp_session.borrow_mut();
 453
 454         if let IncrCompSession::Active { .. } = *incr_comp_session { } else {
 455             bug!("Trying to finalize IncrCompSession `{:?}`", *incr_comp_session)
 456         }
 457
 458         // Note: This will also drop the lock file, thus unlocking the directory
 459         *incr_comp_session = IncrCompSession::Finalized {
 460             session_directory: new_directory_path,
 461         };
 462     }
 463
 464     pub fn mark_incr_comp_session_as_invalid(&self) {
 465         let mut incr_comp_session = self.incr_comp_session.borrow_mut();
 466
 467         let session_directory = match *incr_comp_session {
 468             IncrCompSession::Active { ref session_directory, .. } => {
 469                 session_directory.clone()
 470             }
 471             _ => bug!("Trying to invalidate IncrCompSession `{:?}`",
 472                       *incr_comp_session),
 473         };
 474
 475         // Note: This will also drop the lock file, thus unlocking the directory
 476         *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors {
 477             session_directory: session_directory
 478         };
 479     }
 480
 481     pub fn incr_comp_session_dir(&self) -> cell::Ref<PathBuf> {
 482         let incr_comp_session = self.incr_comp_session.borrow();
 483         cell::Ref::map(incr_comp_session, |incr_comp_session| {
 484             match *incr_comp_session {
 485                 IncrCompSession::NotInitialized => {
 486                     bug!("Trying to get session directory from IncrCompSession `{:?}`",
 487                         *incr_comp_session)
 488                 }
 489                 IncrCompSession::Active { ref session_directory, .. } |
 490                 IncrCompSession::Finalized { ref session_directory } |
 491                 IncrCompSession::InvalidBecauseOfErrors { ref session_directory } => {
 492                     session_directory
 493                 }
 494             }
 495         })
 496     }
 497
 498     pub fn incr_comp_session_dir_opt(&self) -> Option<cell::Ref<PathBuf>> {
 499         if self.opts.incremental.is_some() {
 500             Some(self.incr_comp_session_dir())
 501         } else {
 502             None
 503         }
 504     }
 505
 506     pub fn print_perf_stats(&self) {
 507         println!("Total time spent computing SVHs:               {}",
 508                  duration_to_secs_str(self.perf_stats.svh_time.get()));
 509         println!("Total time spent computing incr. comp. hashes: {}",
 510                  duration_to_secs_str(self.perf_stats.incr_comp_hashes_time.get()));
 511         println!("Total number of incr. comp. hashes computed:   {}",
 512                  self.perf_stats.incr_comp_hashes_count.get());
 513         println!("Total number of bytes hashed for incr. comp.:  {}",
 514                  self.perf_stats.incr_comp_bytes_hashed.get());
 515         println!("Average bytes hashed per incr. comp. HIR node: {}",
 516                  self.perf_stats.incr_comp_bytes_hashed.get() /
 517                  self.perf_stats.incr_comp_hashes_count.get());
 518         println!("Total time spent computing symbol hashes:      {}",
 519                  duration_to_secs_str(self.perf_stats.symbol_hash_time.get()));
 520         println!("Total time spent decoding DefPath tables:      {}",
 521                  duration_to_secs_str(self.perf_stats.decode_def_path_tables_time.get()));
 522     }
 523
 524     /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
 525     /// This expends fuel if applicable, and records fuel if applicable.
 526     pub fn consider_optimizing<T: Fn() -> String>(&self, crate_name: &str, msg: T) -> bool {
 527         let mut ret = true;
 528         match self.optimization_fuel_crate {
 529             Some(ref c) if c == crate_name => {
 530                 let fuel = self.optimization_fuel_limit.get();
 531                 ret = fuel != 0;
 532                 if fuel == 0 && !self.out_of_fuel.get() {
 533                     println!("optimization-fuel-exhausted: {}", msg());
 534                     self.out_of_fuel.set(true);
 535                 } else if fuel > 0 {
 536                     self.optimization_fuel_limit.set(fuel-1);
 537                 }
 538             }
 539             _ => {}
 540         }
 541         match self.print_fuel_crate {
 542             Some(ref c) if c == crate_name=> {
 543                 self.print_fuel.set(self.print_fuel.get()+1);
 544             },
 545             _ => {}
 546         }
 547         ret
 548     }
 549 }
 550
 551 pub fn build_session(sopts: config::Options,
 552                      dep_graph: &DepGraph,
 553                      local_crate_source_file: Option<PathBuf>,
 554                      registry: errors::registry::Registry,
 555                      cstore: Rc<CrateStore>)
 556                      -> Session {
 557     let file_path_mapping = sopts.file_path_mapping();
 558
 559     build_session_with_codemap(sopts,
 560                                dep_graph,
 561                                local_crate_source_file,
 562                                registry,
 563                                cstore,
 564                                Rc::new(codemap::CodeMap::new(file_path_mapping)),
 565                                None)
 566 }
 567
 568 pub fn build_session_with_codemap(sopts: config::Options,
 569                                   dep_graph: &DepGraph,
 570                                   local_crate_source_file: Option<PathBuf>,
 571                                   registry: errors::registry::Registry,
 572                                   cstore: Rc<CrateStore>,
 573                                   codemap: Rc<codemap::CodeMap>,
 574                                   emitter_dest: Option<Box<Write + Send>>)
 575                                   -> Session {
 576     // FIXME: This is not general enough to make the warning lint completely override
 577     // normal diagnostic warnings, since the warning lint can also be denied and changed
 578     // later via the source code.
 579     let can_print_warnings = sopts.lint_opts
 580         .iter()
 581         .filter(|&&(ref key, _)| *key == "warnings")
 582         .map(|&(_, ref level)| *level != lint::Allow)
 583         .last()
 584         .unwrap_or(true);
 585     let treat_err_as_bug = sopts.debugging_opts.treat_err_as_bug;
 586
 587     let emitter: Box<Emitter> = match (sopts.error_format, emitter_dest) {
 588         (config::ErrorOutputType::HumanReadable(color_config), None) => {
 589             Box::new(EmitterWriter::stderr(color_config,
 590                                            Some(codemap.clone())))
 591         }
 592         (config::ErrorOutputType::HumanReadable(_), Some(dst)) => {
 593             Box::new(EmitterWriter::new(dst,
 594                                         Some(codemap.clone())))
 595         }
 596         (config::ErrorOutputType::Json, None) => {
 597             Box::new(JsonEmitter::stderr(Some(registry), codemap.clone()))
 598         }
 599         (config::ErrorOutputType::Json, Some(dst)) => {
 600             Box::new(JsonEmitter::new(dst, Some(registry), codemap.clone()))
 601         }
 602     };
 603
 604     let diagnostic_handler =
 605         errors::Handler::with_emitter(can_print_warnings,
 606                                       treat_err_as_bug,
 607                                       emitter);
 608
 609     build_session_(sopts,
 610                    dep_graph,
 611                    local_crate_source_file,
 612                    diagnostic_handler,
 613                    codemap,
 614                    cstore)
 615 }
 616
 617 pub fn build_session_(sopts: config::Options,
 618                       dep_graph: &DepGraph,
 619                       local_crate_source_file: Option<PathBuf>,
 620                       span_diagnostic: errors::Handler,
 621                       codemap: Rc<codemap::CodeMap>,
 622                       cstore: Rc<CrateStore>)
 623                       -> Session {
 624     let host = match Target::search(config::host_triple()) {
 625         Ok(t) => t,
 626         Err(e) => {
 627             panic!(span_diagnostic.fatal(&format!("Error loading host specification: {}", e)));
 628         }
 629     };
 630     let target_cfg = config::build_target_config(&sopts, &span_diagnostic);
 631
 632     // Hook up the codemap with a callback that allows it to register FileMap
 633     // accesses with the dependency graph.
 634     let cm_depgraph = dep_graph.clone();
 635     let codemap_dep_tracking_callback = Box::new(move |filemap: &FileMap| {
 636         let def_id = DefId {
 637             krate: CrateNum::from_u32(filemap.crate_of_origin),
 638             index: CRATE_DEF_INDEX,
 639         };
 640         let name = Arc::new(filemap.name.clone());
 641         let dep_node = DepNode::FileMap(def_id, name);
 642
 643         cm_depgraph.read(dep_node);
 644     });
 645     codemap.set_dep_tracking_callback(codemap_dep_tracking_callback);
 646
 647     let p_s = parse::ParseSess::with_span_handler(span_diagnostic, codemap);
 648     let default_sysroot = match sopts.maybe_sysroot {
 649         Some(_) => None,
 650         None => Some(filesearch::get_or_default_sysroot())
 651     };
 652
 653     let file_path_mapping = sopts.file_path_mapping();
 654
 655     // Make the path absolute, if necessary
 656     let local_crate_source_file = local_crate_source_file.map(|path| {
 657         file_path_mapping.map_prefix(path.to_string_lossy().into_owned()).0
 658     });
 659
 660     let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone());
 661     let optimization_fuel_limit = Cell::new(sopts.debugging_opts.fuel.as_ref()
 662         .map(|i| i.1).unwrap_or(0));
 663     let print_fuel_crate = sopts.debugging_opts.print_fuel.clone();
 664     let print_fuel = Cell::new(0);
 665
 666     let working_dir = env::current_dir().unwrap().to_string_lossy().into_owned();
 667     let working_dir = file_path_mapping.map_prefix(working_dir);
 668
 669     let sess = Session {
 670         dep_graph: dep_graph.clone(),
 671         target: target_cfg,
 672         host: host,
 673         opts: sopts,
 674         cstore: cstore,
 675         parse_sess: p_s,
 676         // For a library crate, this is always none
 677         entry_fn: RefCell::new(None),
 678         entry_type: Cell::new(None),
 679         plugin_registrar_fn: Cell::new(None),
 680         derive_registrar_fn: Cell::new(None),
 681         default_sysroot: default_sysroot,
 682         local_crate_source_file: local_crate_source_file,
 683         working_dir: working_dir,
 684         lint_store: RefCell::new(lint::LintStore::new()),
 685         lints: RefCell::new(lint::LintTable::new()),
 686         one_time_diagnostics: RefCell::new(FxHashSet()),
 687         plugin_llvm_passes: RefCell::new(Vec::new()),
 688         plugin_attributes: RefCell::new(Vec::new()),
 689         crate_types: RefCell::new(Vec::new()),
 690         dependency_formats: RefCell::new(FxHashMap()),
 691         crate_disambiguator: RefCell::new(Symbol::intern("")),
 692         features: RefCell::new(feature_gate::Features::new()),
 693         recursion_limit: Cell::new(64),
 694         type_length_limit: Cell::new(1048576),
 695         next_node_id: Cell::new(NodeId::new(1)),
 696         injected_allocator: Cell::new(None),
 697         injected_panic_runtime: Cell::new(None),
 698         imported_macro_spans: RefCell::new(HashMap::new()),
 699         incr_comp_session: RefCell::new(IncrCompSession::NotInitialized),
 700         perf_stats: PerfStats {
 701             svh_time: Cell::new(Duration::from_secs(0)),
 702             incr_comp_hashes_time: Cell::new(Duration::from_secs(0)),
 703             incr_comp_hashes_count: Cell::new(0),
 704             incr_comp_bytes_hashed: Cell::new(0),
 705             symbol_hash_time: Cell::new(Duration::from_secs(0)),
 706             decode_def_path_tables_time: Cell::new(Duration::from_secs(0)),
 707         },
 708         code_stats: RefCell::new(CodeStats::new()),
 709         optimization_fuel_crate: optimization_fuel_crate,
 710         optimization_fuel_limit: optimization_fuel_limit,
 711         print_fuel_crate: print_fuel_crate,
 712         print_fuel: print_fuel,
 713         out_of_fuel: Cell::new(false),
 714     };
 715
 716     init_llvm(&sess);
 717
 718     sess
 719 }
 720
 721 /// Holds data on the current incremental compilation session, if there is one.
 722 #[derive(Debug)]
 723 pub enum IncrCompSession {
 724     // This is the state the session will be in until the incr. comp. dir is
 725     // needed.
 726     NotInitialized,
 727     // This is the state during which the session directory is private and can
 728     // be modified.
 729     Active {
 730         session_directory: PathBuf,
 731         lock_file: flock::Lock,
 732     },
 733     // This is the state after the session directory has been finalized. In this
 734     // state, the contents of the directory must not be modified any more.
 735     Finalized {
 736         session_directory: PathBuf,
 737     },
 738     // This is an error state that is reached when some compilation error has
 739     // occurred. It indicates that the contents of the session directory must
 740     // not be used, since they might be invalid.
 741     InvalidBecauseOfErrors {
 742         session_directory: PathBuf,
 743     }
 744 }
 745
 746 fn init_llvm(sess: &Session) {
 747     unsafe {
 748         // Before we touch LLVM, make sure that multithreading is enabled.
 749         use std::sync::Once;
 750         static INIT: Once = Once::new();
 751         static mut POISONED: bool = false;
 752         INIT.call_once(|| {
 753             if llvm::LLVMStartMultithreaded() != 1 {
 754                 // use an extra bool to make sure that all future usage of LLVM
 755                 // cannot proceed despite the Once not running more than once.
 756                 POISONED = true;
 757             }
 758
 759             configure_llvm(sess);
 760         });
 761
 762         if POISONED {
 763             bug!("couldn't enable multi-threaded LLVM");
 764         }
 765     }
 766 }
 767
 768 unsafe fn configure_llvm(sess: &Session) {
 769     let mut llvm_c_strs = Vec::new();
 770     let mut llvm_args = Vec::new();
 771
 772     {
 773         let mut add = |arg: &str| {
 774             let s = CString::new(arg).unwrap();
 775             llvm_args.push(s.as_ptr());
 776             llvm_c_strs.push(s);
 777         };
 778         add("rustc"); // fake program name
 779         if sess.time_llvm_passes() { add("-time-passes"); }
 780         if sess.print_llvm_passes() { add("-debug-pass=Structure"); }
 781
 782         for arg in &sess.opts.cg.llvm_args {
 783             add(&(*arg));
 784         }
 785     }
 786
 787     llvm::LLVMInitializePasses();
 788
 789     llvm::initialize_available_targets();
 790
 791     llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
 792                                  llvm_args.as_ptr());
 793 }
 794
 795 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
 796     let emitter: Box<Emitter> = match output {
 797         config::ErrorOutputType::HumanReadable(color_config) => {
 798             Box::new(EmitterWriter::stderr(color_config,
 799                                            None))
 800         }
 801         config::ErrorOutputType::Json => Box::new(JsonEmitter::basic()),
 802     };
 803     let handler = errors::Handler::with_emitter(true, false, emitter);
 804     handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal);
 805     panic!(errors::FatalError);
 806 }
 807
 808 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
 809     let emitter: Box<Emitter> = match output {
 810         config::ErrorOutputType::HumanReadable(color_config) => {
 811             Box::new(EmitterWriter::stderr(color_config,
 812                                            None))
 813         }
 814         config::ErrorOutputType::Json => Box::new(JsonEmitter::basic()),
 815     };
 816     let handler = errors::Handler::with_emitter(true, false, emitter);
 817     handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
 818 }
 819
 820 // Err(0) means compilation was stopped, but no errors were found.
 821 // This would be better as a dedicated enum, but using try! is so convenient.
 822 pub type CompileResult = Result<(), usize>;
 823
 824 pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
 825     if err_count == 0 {
 826         Ok(())
 827     } else {
 828         Err(err_count)
 829     }
 830 }
 831
 832 #[cold]
 833 #[inline(never)]
 834 pub fn bug_fmt(file: &'static str, line: u32, args: fmt::Arguments) -> ! {
 835     // this wrapper mostly exists so I don't have to write a fully
 836     // qualified path of None::<Span> inside the bug!() macro defintion
 837     opt_span_bug_fmt(file, line, None::<Span>, args);
 838 }
 839
 840 #[cold]
 841 #[inline(never)]
 842 pub fn span_bug_fmt<S: Into<MultiSpan>>(file: &'static str,
 843                                         line: u32,
 844                                         span: S,
 845                                         args: fmt::Arguments) -> ! {
 846     opt_span_bug_fmt(file, line, Some(span), args);
 847 }
 848
 849 fn opt_span_bug_fmt<S: Into<MultiSpan>>(file: &'static str,
 850                                         line: u32,
 851                                         span: Option<S>,
 852                                         args: fmt::Arguments) -> ! {
 853     tls::with_opt(move |tcx| {
 854         let msg = format!("{}:{}: {}", file, line, args);
 855         match (tcx, span) {
 856             (Some(tcx), Some(span)) => tcx.sess.diagnostic().span_bug(span, &msg),
 857             (Some(tcx), None) => tcx.sess.diagnostic().bug(&msg),
 858             (None, _) => panic!(msg)
 859         }
 860     });
 861     unreachable!();
 862 }