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