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.
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.
11 pub use self::code_stats::{DataTypeKind, SizeKind, FieldInfo, VariantInfo};
12 use self::code_stats::CodeStats;
14 use dep_graph::cgu_reuse_tracker::CguReuseTracker;
15 use hir::def_id::CrateNum;
16 use rustc_data_structures::fingerprint::Fingerprint;
19 use lint::builtin::BuiltinLintDiagnostics;
20 use middle::allocator::AllocatorKind;
21 use middle::dependency_format;
22 use session::search_paths::PathKind;
23 use session::config::{OutputType, Lto};
24 use util::nodemap::{FxHashMap, FxHashSet};
25 use util::common::{duration_to_secs_str, ErrorReported};
26 use util::common::ProfileQueriesMsg;
28 use rustc_data_structures::base_n;
29 use rustc_data_structures::sync::{self, Lrc, Lock, LockCell, OneThread, Once, RwLock};
31 use syntax::ast::NodeId;
32 use errors::{self, DiagnosticBuilder, DiagnosticId, Applicability};
33 use errors::emitter::{Emitter, EmitterWriter};
34 use syntax::edition::Edition;
35 use syntax::json::JsonEmitter;
36 use syntax::feature_gate;
38 use syntax::parse::ParseSess;
39 use syntax::{ast, source_map};
40 use syntax::feature_gate::AttributeType;
41 use syntax_pos::{MultiSpan, Span};
42 use util::profiling::SelfProfiler;
44 use rustc_target::spec::PanicStrategy;
45 use rustc_target::spec::{Target, TargetTriple};
46 use rustc_data_structures::flock;
47 use jobserver::Client;
50 use std::cell::{self, Cell, RefCell};
54 use std::path::{Path, PathBuf};
55 use std::time::Duration;
57 use std::sync::atomic::{AtomicUsize, Ordering};
64 /// Represents the data associated with a compilation
65 /// session for a single crate.
67 pub target: config::Config,
69 pub opts: config::Options,
70 pub parse_sess: ParseSess,
71 /// For a library crate, this is always none
72 pub entry_fn: Once<Option<(NodeId, Span, config::EntryFnType)>>,
73 pub plugin_registrar_fn: Once<Option<ast::NodeId>>,
74 pub derive_registrar_fn: Once<Option<ast::NodeId>>,
75 pub default_sysroot: Option<PathBuf>,
76 /// The name of the root source file of the crate, in the local file system.
77 /// `None` means that there is no source file.
78 pub local_crate_source_file: Option<PathBuf>,
79 /// The directory the compiler has been executed in plus a flag indicating
80 /// if the value stored here has been affected by path remapping.
81 pub working_dir: (PathBuf, bool),
83 // FIXME: lint_store and buffered_lints are not thread-safe,
84 // but are only used in a single thread
85 pub lint_store: RwLock<lint::LintStore>,
86 pub buffered_lints: Lock<Option<lint::LintBuffer>>,
88 /// Set of (DiagnosticId, Option<Span>, message) tuples tracking
89 /// (sub)diagnostics that have been set once, but should not be set again,
90 /// in order to avoid redundantly verbose output (Issue #24690, #44953).
91 pub one_time_diagnostics: Lock<FxHashSet<(DiagnosticMessageId, Option<Span>, String)>>,
92 pub plugin_llvm_passes: OneThread<RefCell<Vec<String>>>,
93 pub plugin_attributes: OneThread<RefCell<Vec<(String, AttributeType)>>>,
94 pub crate_types: Once<Vec<config::CrateType>>,
95 pub dependency_formats: Once<dependency_format::Dependencies>,
96 /// The crate_disambiguator is constructed out of all the `-C metadata`
97 /// arguments passed to the compiler. Its value together with the crate-name
98 /// forms a unique global identifier for the crate. It is used to allow
99 /// multiple crates with the same name to coexist. See the
100 /// rustc_codegen_llvm::back::symbol_names module for more information.
101 pub crate_disambiguator: Once<CrateDisambiguator>,
103 features: Once<feature_gate::Features>,
105 /// The maximum recursion limit for potentially infinitely recursive
106 /// operations such as auto-dereference and monomorphization.
107 pub recursion_limit: Once<usize>,
109 /// The maximum length of types during monomorphization.
110 pub type_length_limit: Once<usize>,
112 /// The maximum number of stackframes allowed in const eval
113 pub const_eval_stack_frame_limit: usize,
115 /// The metadata::creader module may inject an allocator/panic_runtime
116 /// dependency if it didn't already find one, and this tracks what was
118 pub injected_allocator: Once<Option<CrateNum>>,
119 pub allocator_kind: Once<Option<AllocatorKind>>,
120 pub injected_panic_runtime: Once<Option<CrateNum>>,
122 /// Map from imported macro spans (which consist of
123 /// the localized span for the macro body) to the
124 /// macro name and definition span in the source crate.
125 pub imported_macro_spans: OneThread<RefCell<FxHashMap<Span, (String, Span)>>>,
127 incr_comp_session: OneThread<RefCell<IncrCompSession>>,
128 /// Used for incremental compilation tests. Will only be populated if
129 /// `-Zquery-dep-graph` is specified.
130 pub cgu_reuse_tracker: CguReuseTracker,
132 /// Used by -Z profile-queries in util::common
133 pub profile_channel: Lock<Option<mpsc::Sender<ProfileQueriesMsg>>>,
135 /// Used by -Z self-profile
136 pub self_profiling: Lock<SelfProfiler>,
138 /// Some measurements that are being gathered during compilation.
139 pub perf_stats: PerfStats,
141 /// Data about code being compiled, gathered during compilation.
142 pub code_stats: Lock<CodeStats>,
144 next_node_id: OneThread<Cell<ast::NodeId>>,
146 /// If -zfuel=crate=n is specified, Some(crate).
147 optimization_fuel_crate: Option<String>,
148 /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0.
149 optimization_fuel_limit: LockCell<u64>,
150 /// We're rejecting all further optimizations.
151 out_of_fuel: LockCell<bool>,
153 // The next two are public because the driver needs to read them.
154 /// If -zprint-fuel=crate, Some(crate).
155 pub print_fuel_crate: Option<String>,
156 /// Always set to zero and incremented so that we can print fuel expended by a crate.
157 pub print_fuel: LockCell<u64>,
159 /// Loaded up early on in the initialization of this `Session` to avoid
160 /// false positives about a job server in our environment.
161 pub jobserver: Client,
163 /// Metadata about the allocators for the current crate being compiled
164 pub has_global_allocator: Once<bool>,
166 /// Metadata about the panic handlers for the current crate being compiled
167 pub has_panic_handler: Once<bool>,
169 /// Cap lint level specified by a driver specifically.
170 pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
173 pub struct PerfStats {
174 /// The accumulated time spent on computing symbol hashes
175 pub symbol_hash_time: Lock<Duration>,
176 /// The accumulated time spent decoding def path tables from metadata
177 pub decode_def_path_tables_time: Lock<Duration>,
178 /// Total number of values canonicalized queries constructed.
179 pub queries_canonicalized: AtomicUsize,
180 /// Number of times this query is invoked.
181 pub normalize_ty_after_erasing_regions: AtomicUsize,
182 /// Number of times this query is invoked.
183 pub normalize_projection_ty: AtomicUsize,
186 /// Enum to support dispatch of one-time diagnostics (in Session.diag_once)
187 enum DiagnosticBuilderMethod {
190 SpanSuggestion(String), // suggestion
191 // add more variants as needed to support one-time diagnostics
194 /// Diagnostic message ID—used by `Session.one_time_diagnostics` to avoid
195 /// emitting the same message more than once
196 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
197 pub enum DiagnosticMessageId {
198 ErrorId(u16), // EXXXX error code as integer
199 LintId(lint::LintId),
200 StabilityId(u32), // issue number
203 impl From<&'static lint::Lint> for DiagnosticMessageId {
204 fn from(lint: &'static lint::Lint) -> Self {
205 DiagnosticMessageId::LintId(lint::LintId::of(lint))
210 pub fn local_crate_disambiguator(&self) -> CrateDisambiguator {
211 *self.crate_disambiguator.get()
214 pub fn struct_span_warn<'a, S: Into<MultiSpan>>(
218 ) -> DiagnosticBuilder<'a> {
219 self.diagnostic().struct_span_warn(sp, msg)
221 pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(
226 ) -> DiagnosticBuilder<'a> {
227 self.diagnostic().struct_span_warn_with_code(sp, msg, code)
229 pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
230 self.diagnostic().struct_warn(msg)
232 pub fn struct_span_err<'a, S: Into<MultiSpan>>(
236 ) -> DiagnosticBuilder<'a> {
237 self.diagnostic().struct_span_err(sp, msg)
239 pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(
244 ) -> DiagnosticBuilder<'a> {
245 self.diagnostic().struct_span_err_with_code(sp, msg, code)
247 // FIXME: This method should be removed (every error should have an associated error code).
248 pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
249 self.diagnostic().struct_err(msg)
251 pub fn struct_err_with_code<'a>(
255 ) -> DiagnosticBuilder<'a> {
256 self.diagnostic().struct_err_with_code(msg, code)
258 pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(
262 ) -> DiagnosticBuilder<'a> {
263 self.diagnostic().struct_span_fatal(sp, msg)
265 pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(
270 ) -> DiagnosticBuilder<'a> {
271 self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
273 pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
274 self.diagnostic().struct_fatal(msg)
277 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
278 self.diagnostic().span_fatal(sp, msg).raise()
280 pub fn span_fatal_with_code<S: Into<MultiSpan>>(
287 .span_fatal_with_code(sp, msg, code)
290 pub fn fatal(&self, msg: &str) -> ! {
291 self.diagnostic().fatal(msg).raise()
293 pub fn span_err_or_warn<S: Into<MultiSpan>>(&self, is_warning: bool, sp: S, msg: &str) {
295 self.span_warn(sp, msg);
297 self.span_err(sp, msg);
300 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
301 self.diagnostic().span_err(sp, msg)
303 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
304 self.diagnostic().span_err_with_code(sp, &msg, code)
306 pub fn err(&self, msg: &str) {
307 self.diagnostic().err(msg)
309 pub fn err_count(&self) -> usize {
310 self.diagnostic().err_count()
312 pub fn has_errors(&self) -> bool {
313 self.diagnostic().has_errors()
315 pub fn abort_if_errors(&self) {
316 self.diagnostic().abort_if_errors();
318 pub fn compile_status(&self) -> Result<(), CompileIncomplete> {
319 compile_result_from_err_count(self.err_count())
321 pub fn track_errors<F, T>(&self, f: F) -> Result<T, ErrorReported>
325 let old_count = self.err_count();
327 let errors = self.err_count() - old_count;
334 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
335 self.diagnostic().span_warn(sp, msg)
337 pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
338 self.diagnostic().span_warn_with_code(sp, msg, code)
340 pub fn warn(&self, msg: &str) {
341 self.diagnostic().warn(msg)
343 pub fn opt_span_warn<S: Into<MultiSpan>>(&self, opt_sp: Option<S>, msg: &str) {
345 Some(sp) => self.span_warn(sp, msg),
346 None => self.warn(msg),
349 /// Delay a span_bug() call until abort_if_errors()
350 pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
351 self.diagnostic().delay_span_bug(sp, msg)
353 pub fn note_without_error(&self, msg: &str) {
354 self.diagnostic().note_without_error(msg)
356 pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
357 self.diagnostic().span_note_without_error(sp, msg)
359 pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
360 self.diagnostic().span_unimpl(sp, msg)
362 pub fn unimpl(&self, msg: &str) -> ! {
363 self.diagnostic().unimpl(msg)
366 pub fn buffer_lint<S: Into<MultiSpan>>(
368 lint: &'static lint::Lint,
373 match *self.buffered_lints.borrow_mut() {
374 Some(ref mut buffer) => {
375 buffer.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal)
377 None => bug!("can't buffer lints after HIR lowering"),
381 pub fn buffer_lint_with_diagnostic<S: Into<MultiSpan>>(
383 lint: &'static lint::Lint,
387 diagnostic: BuiltinLintDiagnostics,
389 match *self.buffered_lints.borrow_mut() {
390 Some(ref mut buffer) => buffer.add_lint(lint, id, sp.into(), msg, diagnostic),
391 None => bug!("can't buffer lints after HIR lowering"),
395 pub fn reserve_node_ids(&self, count: usize) -> ast::NodeId {
396 let id = self.next_node_id.get();
398 match id.as_usize().checked_add(count) {
400 self.next_node_id.set(ast::NodeId::new(next));
402 None => bug!("Input too large, ran out of node ids!"),
407 pub fn next_node_id(&self) -> NodeId {
408 self.reserve_node_ids(1)
410 pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler {
411 &self.parse_sess.span_diagnostic
414 /// Analogous to calling methods on the given `DiagnosticBuilder`, but
415 /// deduplicates on lint ID, span (if any), and message for this `Session`
416 fn diag_once<'a, 'b>(
418 diag_builder: &'b mut DiagnosticBuilder<'a>,
419 method: DiagnosticBuilderMethod,
420 msg_id: DiagnosticMessageId,
422 span_maybe: Option<Span>,
424 let id_span_message = (msg_id, span_maybe, message.to_owned());
425 let fresh = self.one_time_diagnostics
427 .insert(id_span_message);
430 DiagnosticBuilderMethod::Note => {
431 diag_builder.note(message);
433 DiagnosticBuilderMethod::SpanNote => {
434 let span = span_maybe.expect("span_note needs a span");
435 diag_builder.span_note(span, message);
437 DiagnosticBuilderMethod::SpanSuggestion(suggestion) => {
438 let span = span_maybe.expect("span_suggestion_* needs a span");
439 diag_builder.span_suggestion_with_applicability(
443 Applicability::Unspecified,
450 pub fn diag_span_note_once<'a, 'b>(
452 diag_builder: &'b mut DiagnosticBuilder<'a>,
453 msg_id: DiagnosticMessageId,
459 DiagnosticBuilderMethod::SpanNote,
466 pub fn diag_note_once<'a, 'b>(
468 diag_builder: &'b mut DiagnosticBuilder<'a>,
469 msg_id: DiagnosticMessageId,
474 DiagnosticBuilderMethod::Note,
481 pub fn diag_span_suggestion_once<'a, 'b>(
483 diag_builder: &'b mut DiagnosticBuilder<'a>,
484 msg_id: DiagnosticMessageId,
491 DiagnosticBuilderMethod::SpanSuggestion(suggestion),
498 pub fn source_map<'a>(&'a self) -> &'a source_map::SourceMap {
499 self.parse_sess.source_map()
501 pub fn verbose(&self) -> bool {
502 self.opts.debugging_opts.verbose
504 pub fn time_passes(&self) -> bool {
505 self.opts.debugging_opts.time_passes
507 pub fn profile_queries(&self) -> bool {
508 self.opts.debugging_opts.profile_queries
509 || self.opts.debugging_opts.profile_queries_and_keys
511 pub fn profile_queries_and_keys(&self) -> bool {
512 self.opts.debugging_opts.profile_queries_and_keys
514 pub fn count_llvm_insns(&self) -> bool {
515 self.opts.debugging_opts.count_llvm_insns
517 pub fn time_llvm_passes(&self) -> bool {
518 self.opts.debugging_opts.time_llvm_passes
520 pub fn codegen_stats(&self) -> bool {
521 self.opts.debugging_opts.codegen_stats
523 pub fn meta_stats(&self) -> bool {
524 self.opts.debugging_opts.meta_stats
526 pub fn asm_comments(&self) -> bool {
527 self.opts.debugging_opts.asm_comments
529 pub fn verify_llvm_ir(&self) -> bool {
530 self.opts.debugging_opts.verify_llvm_ir
532 pub fn borrowck_stats(&self) -> bool {
533 self.opts.debugging_opts.borrowck_stats
535 pub fn print_llvm_passes(&self) -> bool {
536 self.opts.debugging_opts.print_llvm_passes
539 /// Get the features enabled for the current compilation session.
540 /// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents
541 /// dependency tracking. Use tcx.features() instead.
543 pub fn features_untracked(&self) -> &feature_gate::Features {
547 pub fn init_features(&self, features: feature_gate::Features) {
548 self.features.set(features);
551 /// Calculates the flavor of LTO to use for this compilation.
552 pub fn lto(&self) -> config::Lto {
553 // If our target has codegen requirements ignore the command line
554 if self.target.target.options.requires_lto {
555 return config::Lto::Fat;
558 // If the user specified something, return that. If they only said `-C
559 // lto` and we've for whatever reason forced off ThinLTO via the CLI,
560 // then ensure we can't use a ThinLTO.
561 match self.opts.cg.lto {
562 config::LtoCli::Unspecified => {
563 // The compiler was invoked without the `-Clto` flag. Fall
564 // through to the default handling
566 config::LtoCli::No => {
567 // The user explicitly opted out of any kind of LTO
568 return config::Lto::No;
570 config::LtoCli::Yes |
571 config::LtoCli::Fat |
572 config::LtoCli::NoParam => {
573 // All of these mean fat LTO
574 return config::Lto::Fat;
576 config::LtoCli::Thin => {
577 return if self.opts.cli_forced_thinlto_off {
585 // Ok at this point the target doesn't require anything and the user
586 // hasn't asked for anything. Our next decision is whether or not
587 // we enable "auto" ThinLTO where we use multiple codegen units and
588 // then do ThinLTO over those codegen units. The logic below will
589 // either return `No` or `ThinLocal`.
591 // If processing command line options determined that we're incompatible
592 // with ThinLTO (e.g. `-C lto --emit llvm-ir`) then return that option.
593 if self.opts.cli_forced_thinlto_off {
594 return config::Lto::No;
597 // If `-Z thinlto` specified process that, but note that this is mostly
598 // a deprecated option now that `-C lto=thin` exists.
599 if let Some(enabled) = self.opts.debugging_opts.thinlto {
601 return config::Lto::ThinLocal;
603 return config::Lto::No;
607 // If there's only one codegen unit and LTO isn't enabled then there's
608 // no need for ThinLTO so just return false.
609 if self.codegen_units() == 1 {
610 return config::Lto::No;
613 // Now we're in "defaults" territory. By default we enable ThinLTO for
614 // optimized compiles (anything greater than O0).
615 match self.opts.optimize {
616 config::OptLevel::No => config::Lto::No,
617 _ => config::Lto::ThinLocal,
621 /// Returns the panic strategy for this compile session. If the user explicitly selected one
622 /// using '-C panic', use that, otherwise use the panic strategy defined by the target.
623 pub fn panic_strategy(&self) -> PanicStrategy {
627 .unwrap_or(self.target.target.options.panic_strategy)
629 pub fn fewer_names(&self) -> bool {
630 let more_names = self.opts
632 .contains_key(&OutputType::LlvmAssembly)
633 || self.opts.output_types.contains_key(&OutputType::Bitcode);
634 self.opts.debugging_opts.fewer_names || !more_names
637 pub fn no_landing_pads(&self) -> bool {
638 self.opts.debugging_opts.no_landing_pads || self.panic_strategy() == PanicStrategy::Abort
640 pub fn unstable_options(&self) -> bool {
641 self.opts.debugging_opts.unstable_options
643 pub fn overflow_checks(&self) -> bool {
647 .or(self.opts.debugging_opts.force_overflow_checks)
648 .unwrap_or(self.opts.debug_assertions)
651 pub fn crt_static(&self) -> bool {
652 // If the target does not opt in to crt-static support, use its default.
653 if self.target.target.options.crt_static_respected {
654 self.crt_static_feature()
656 self.target.target.options.crt_static_default
660 pub fn crt_static_feature(&self) -> bool {
661 let requested_features = self.opts.cg.target_feature.split(',');
662 let found_negative = requested_features.clone().any(|r| r == "-crt-static");
663 let found_positive = requested_features.clone().any(|r| r == "+crt-static");
665 // If the target we're compiling for requests a static crt by default,
666 // then see if the `-crt-static` feature was passed to disable that.
667 // Otherwise if we don't have a static crt by default then see if the
668 // `+crt-static` feature was passed.
669 if self.target.target.options.crt_static_default {
676 pub fn must_not_eliminate_frame_pointers(&self) -> bool {
677 if let Some(x) = self.opts.cg.force_frame_pointers {
680 !self.target.target.options.eliminate_frame_pointer
684 /// Returns the symbol name for the registrar function,
685 /// given the crate Svh and the function DefIndex.
686 pub fn generate_plugin_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
688 "__rustc_plugin_registrar_{}__",
689 disambiguator.to_fingerprint().to_hex()
693 pub fn generate_derive_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
695 "__rustc_derive_registrar_{}__",
696 disambiguator.to_fingerprint().to_hex()
700 pub fn sysroot<'a>(&'a self) -> &'a Path {
701 match self.opts.maybe_sysroot {
702 Some(ref sysroot) => sysroot,
703 None => self.default_sysroot
705 .expect("missing sysroot and default_sysroot in Session"),
708 pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch {
709 filesearch::FileSearch::new(
711 self.opts.target_triple.triple(),
712 &self.opts.search_paths,
716 pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch {
717 filesearch::FileSearch::new(
719 config::host_triple(),
720 &self.opts.search_paths,
725 pub fn set_incr_session_load_dep_graph(&self, load: bool) {
726 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
728 match *incr_comp_session {
729 IncrCompSession::Active {
730 ref mut load_dep_graph,
733 *load_dep_graph = load;
739 pub fn incr_session_load_dep_graph(&self) -> bool {
740 let incr_comp_session = self.incr_comp_session.borrow();
741 match *incr_comp_session {
742 IncrCompSession::Active { load_dep_graph, .. } => load_dep_graph,
747 pub fn init_incr_comp_session(
749 session_dir: PathBuf,
750 lock_file: flock::Lock,
751 load_dep_graph: bool,
753 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
755 if let IncrCompSession::NotInitialized = *incr_comp_session {
758 "Trying to initialize IncrCompSession `{:?}`",
763 *incr_comp_session = IncrCompSession::Active {
764 session_directory: session_dir,
770 pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) {
771 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
773 if let IncrCompSession::Active { .. } = *incr_comp_session {
776 "Trying to finalize IncrCompSession `{:?}`",
781 // Note: This will also drop the lock file, thus unlocking the directory
782 *incr_comp_session = IncrCompSession::Finalized {
783 session_directory: new_directory_path,
787 pub fn mark_incr_comp_session_as_invalid(&self) {
788 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
790 let session_directory = match *incr_comp_session {
791 IncrCompSession::Active {
792 ref session_directory,
794 } => session_directory.clone(),
795 IncrCompSession::InvalidBecauseOfErrors { .. } => return,
797 "Trying to invalidate IncrCompSession `{:?}`",
802 // Note: This will also drop the lock file, thus unlocking the directory
803 *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors { session_directory };
806 pub fn incr_comp_session_dir(&self) -> cell::Ref<PathBuf> {
807 let incr_comp_session = self.incr_comp_session.borrow();
810 |incr_comp_session| match *incr_comp_session {
811 IncrCompSession::NotInitialized => bug!(
812 "Trying to get session directory from IncrCompSession `{:?}`",
815 IncrCompSession::Active {
816 ref session_directory,
819 | IncrCompSession::Finalized {
820 ref session_directory,
822 | IncrCompSession::InvalidBecauseOfErrors {
823 ref session_directory,
824 } => session_directory,
829 pub fn incr_comp_session_dir_opt(&self) -> Option<cell::Ref<PathBuf>> {
830 if self.opts.incremental.is_some() {
831 Some(self.incr_comp_session_dir())
837 pub fn profiler<F: FnOnce(&mut SelfProfiler) -> ()>(&self, f: F) {
838 let mut profiler = self.self_profiling.borrow_mut();
842 pub fn print_profiler_results(&self) {
843 let mut profiler = self.self_profiling.borrow_mut();
844 profiler.print_results(&self.opts);
847 pub fn save_json_results(&self) {
848 let profiler = self.self_profiling.borrow();
849 profiler.save_results(&self.opts);
852 pub fn print_perf_stats(&self) {
854 "Total time spent computing symbol hashes: {}",
855 duration_to_secs_str(*self.perf_stats.symbol_hash_time.lock())
858 "Total time spent decoding DefPath tables: {}",
859 duration_to_secs_str(*self.perf_stats.decode_def_path_tables_time.lock())
861 println!("Total queries canonicalized: {}",
862 self.perf_stats.queries_canonicalized.load(Ordering::Relaxed));
863 println!("normalize_ty_after_erasing_regions: {}",
864 self.perf_stats.normalize_ty_after_erasing_regions.load(Ordering::Relaxed));
865 println!("normalize_projection_ty: {}",
866 self.perf_stats.normalize_projection_ty.load(Ordering::Relaxed));
869 /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
870 /// This expends fuel if applicable, and records fuel if applicable.
871 pub fn consider_optimizing<T: Fn() -> String>(&self, crate_name: &str, msg: T) -> bool {
873 match self.optimization_fuel_crate {
874 Some(ref c) if c == crate_name => {
875 assert!(self.query_threads() == 1);
876 let fuel = self.optimization_fuel_limit.get();
878 if fuel == 0 && !self.out_of_fuel.get() {
879 println!("optimization-fuel-exhausted: {}", msg());
880 self.out_of_fuel.set(true);
882 self.optimization_fuel_limit.set(fuel - 1);
887 match self.print_fuel_crate {
888 Some(ref c) if c == crate_name => {
889 assert!(self.query_threads() == 1);
890 self.print_fuel.set(self.print_fuel.get() + 1);
897 /// Returns the number of query threads that should be used for this
899 pub fn query_threads_from_opts(opts: &config::Options) -> usize {
900 opts.debugging_opts.query_threads.unwrap_or(1)
903 /// Returns the number of query threads that should be used for this
905 pub fn query_threads(&self) -> usize {
906 Self::query_threads_from_opts(&self.opts)
909 /// Returns the number of codegen units that should be used for this
911 pub fn codegen_units(&self) -> usize {
912 if let Some(n) = self.opts.cli_forced_codegen_units {
915 if let Some(n) = self.target.target.options.default_codegen_units {
919 // Why is 16 codegen units the default all the time?
921 // The main reason for enabling multiple codegen units by default is to
922 // leverage the ability for the codegen backend to do codegen and
923 // optimization in parallel. This allows us, especially for large crates, to
924 // make good use of all available resources on the machine once we've
925 // hit that stage of compilation. Large crates especially then often
926 // take a long time in codegen/optimization and this helps us amortize that
929 // Note that a high number here doesn't mean that we'll be spawning a
930 // large number of threads in parallel. The backend of rustc contains
931 // global rate limiting through the `jobserver` crate so we'll never
932 // overload the system with too much work, but rather we'll only be
933 // optimizing when we're otherwise cooperating with other instances of
936 // Rather a high number here means that we should be able to keep a lot
937 // of idle cpus busy. By ensuring that no codegen unit takes *too* long
938 // to build we'll be guaranteed that all cpus will finish pretty closely
939 // to one another and we should make relatively optimal use of system
942 // Note that the main cost of codegen units is that it prevents LLVM
943 // from inlining across codegen units. Users in general don't have a lot
944 // of control over how codegen units are split up so it's our job in the
945 // compiler to ensure that undue performance isn't lost when using
946 // codegen units (aka we can't require everyone to slap `#[inline]` on
949 // If we're compiling at `-O0` then the number doesn't really matter too
950 // much because performance doesn't matter and inlining is ok to lose.
951 // In debug mode we just want to try to guarantee that no cpu is stuck
952 // doing work that could otherwise be farmed to others.
954 // In release mode, however (O1 and above) performance does indeed
955 // matter! To recover the loss in performance due to inlining we'll be
956 // enabling ThinLTO by default (the function for which is just below).
957 // This will ensure that we recover any inlining wins we otherwise lost
958 // through codegen unit partitioning.
962 // Ok that's a lot of words but the basic tl;dr; is that we want a high
963 // number here -- but not too high. Additionally we're "safe" to have it
964 // always at the same number at all optimization levels.
966 // As a result 16 was chosen here! Mostly because it was a power of 2
967 // and most benchmarks agreed it was roughly a local optimum. Not very
972 pub fn teach(&self, code: &DiagnosticId) -> bool {
973 self.opts.debugging_opts.teach && self.diagnostic().must_teach(code)
976 /// Are we allowed to use features from the Rust 2018 edition?
977 pub fn rust_2018(&self) -> bool {
978 self.opts.edition >= Edition::Edition2018
981 pub fn edition(&self) -> Edition {
986 pub fn build_session(
987 sopts: config::Options,
988 local_crate_source_file: Option<PathBuf>,
989 registry: errors::registry::Registry,
991 let file_path_mapping = sopts.file_path_mapping();
993 build_session_with_source_map(
995 local_crate_source_file,
997 Lrc::new(source_map::SourceMap::new(file_path_mapping)),
1002 pub fn build_session_with_source_map(
1003 sopts: config::Options,
1004 local_crate_source_file: Option<PathBuf>,
1005 registry: errors::registry::Registry,
1006 source_map: Lrc<source_map::SourceMap>,
1007 emitter_dest: Option<Box<dyn Write + Send>>,
1009 // FIXME: This is not general enough to make the warning lint completely override
1010 // normal diagnostic warnings, since the warning lint can also be denied and changed
1011 // later via the source code.
1012 let warnings_allow = sopts
1015 .filter(|&&(ref key, _)| *key == "warnings")
1016 .map(|&(_, ref level)| *level == lint::Allow)
1019 let cap_lints_allow = sopts.lint_cap.map_or(false, |cap| cap == lint::Allow);
1021 let can_emit_warnings = !(warnings_allow || cap_lints_allow);
1023 let treat_err_as_bug = sopts.debugging_opts.treat_err_as_bug;
1024 let dont_buffer_diagnostics = sopts.debugging_opts.dont_buffer_diagnostics;
1025 let report_delayed_bugs = sopts.debugging_opts.report_delayed_bugs;
1027 let external_macro_backtrace = sopts.debugging_opts.external_macro_backtrace;
1029 let emitter: Box<dyn Emitter + sync::Send> =
1030 match (sopts.error_format, emitter_dest) {
1031 (config::ErrorOutputType::HumanReadable(color_config), None) => Box::new(
1032 EmitterWriter::stderr(
1034 Some(source_map.clone()),
1036 sopts.debugging_opts.teach,
1037 ).ui_testing(sopts.debugging_opts.ui_testing),
1039 (config::ErrorOutputType::HumanReadable(_), Some(dst)) => Box::new(
1040 EmitterWriter::new(dst, Some(source_map.clone()), false, false)
1041 .ui_testing(sopts.debugging_opts.ui_testing),
1043 (config::ErrorOutputType::Json(pretty), None) => Box::new(
1044 JsonEmitter::stderr(
1048 ).ui_testing(sopts.debugging_opts.ui_testing),
1050 (config::ErrorOutputType::Json(pretty), Some(dst)) => Box::new(
1056 ).ui_testing(sopts.debugging_opts.ui_testing),
1058 (config::ErrorOutputType::Short(color_config), None) => Box::new(
1059 EmitterWriter::stderr(color_config, Some(source_map.clone()), true, false),
1061 (config::ErrorOutputType::Short(_), Some(dst)) => {
1062 Box::new(EmitterWriter::new(dst, Some(source_map.clone()), true, false))
1066 let diagnostic_handler = errors::Handler::with_emitter_and_flags(
1068 errors::HandlerFlags {
1071 report_delayed_bugs,
1072 dont_buffer_diagnostics,
1073 external_macro_backtrace,
1074 ..Default::default()
1078 build_session_(sopts, local_crate_source_file, diagnostic_handler, source_map)
1081 pub fn build_session_(
1082 sopts: config::Options,
1083 local_crate_source_file: Option<PathBuf>,
1084 span_diagnostic: errors::Handler,
1085 source_map: Lrc<source_map::SourceMap>,
1087 let host_triple = TargetTriple::from_triple(config::host_triple());
1088 let host = match Target::search(&host_triple) {
1092 .fatal(&format!("Error loading host specification: {}", e))
1096 let target_cfg = config::build_target_config(&sopts, &span_diagnostic);
1098 let p_s = parse::ParseSess::with_span_handler(span_diagnostic, source_map);
1099 let default_sysroot = match sopts.maybe_sysroot {
1101 None => Some(filesearch::get_or_default_sysroot()),
1104 let file_path_mapping = sopts.file_path_mapping();
1106 let local_crate_source_file =
1107 local_crate_source_file.map(|path| file_path_mapping.map_prefix(path).0);
1109 let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone());
1110 let optimization_fuel_limit =
1111 LockCell::new(sopts.debugging_opts.fuel.as_ref().map(|i| i.1).unwrap_or(0));
1112 let print_fuel_crate = sopts.debugging_opts.print_fuel.clone();
1113 let print_fuel = LockCell::new(0);
1115 let working_dir = match env::current_dir() {
1117 Err(e) => p_s.span_diagnostic
1118 .fatal(&format!("Current directory is invalid: {}", e))
1121 let working_dir = file_path_mapping.map_prefix(working_dir);
1123 let cgu_reuse_tracker = if sopts.debugging_opts.query_dep_graph {
1124 CguReuseTracker::new()
1126 CguReuseTracker::new_disabled()
1129 let sess = Session {
1134 // For a library crate, this is always none
1135 entry_fn: Once::new(),
1136 plugin_registrar_fn: Once::new(),
1137 derive_registrar_fn: Once::new(),
1139 local_crate_source_file,
1141 lint_store: RwLock::new(lint::LintStore::new()),
1142 buffered_lints: Lock::new(Some(lint::LintBuffer::new())),
1143 one_time_diagnostics: Lock::new(FxHashSet()),
1144 plugin_llvm_passes: OneThread::new(RefCell::new(Vec::new())),
1145 plugin_attributes: OneThread::new(RefCell::new(Vec::new())),
1146 crate_types: Once::new(),
1147 dependency_formats: Once::new(),
1148 crate_disambiguator: Once::new(),
1149 features: Once::new(),
1150 recursion_limit: Once::new(),
1151 type_length_limit: Once::new(),
1152 const_eval_stack_frame_limit: 100,
1153 next_node_id: OneThread::new(Cell::new(NodeId::new(1))),
1154 injected_allocator: Once::new(),
1155 allocator_kind: Once::new(),
1156 injected_panic_runtime: Once::new(),
1157 imported_macro_spans: OneThread::new(RefCell::new(FxHashMap::default())),
1158 incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)),
1160 self_profiling: Lock::new(SelfProfiler::new()),
1161 profile_channel: Lock::new(None),
1162 perf_stats: PerfStats {
1163 symbol_hash_time: Lock::new(Duration::from_secs(0)),
1164 decode_def_path_tables_time: Lock::new(Duration::from_secs(0)),
1165 queries_canonicalized: AtomicUsize::new(0),
1166 normalize_ty_after_erasing_regions: AtomicUsize::new(0),
1167 normalize_projection_ty: AtomicUsize::new(0),
1169 code_stats: Lock::new(CodeStats::new()),
1170 optimization_fuel_crate,
1171 optimization_fuel_limit,
1174 out_of_fuel: LockCell::new(false),
1175 // Note that this is unsafe because it may misinterpret file descriptors
1176 // on Unix as jobserver file descriptors. We hopefully execute this near
1177 // the beginning of the process though to ensure we don't get false
1178 // positives, or in other words we try to execute this before we open
1179 // any file descriptors ourselves.
1181 // Pick a "reasonable maximum" if we don't otherwise have
1182 // a jobserver in our environment, capping out at 32 so we
1183 // don't take everything down by hogging the process run queue.
1184 // The fixed number is used to have deterministic compilation
1187 // Also note that we stick this in a global because there could be
1188 // multiple `Session` instances in this process, and the jobserver is
1191 static mut GLOBAL_JOBSERVER: *mut Client = 0 as *mut _;
1192 static INIT: std::sync::Once = std::sync::ONCE_INIT;
1194 let client = Client::from_env().unwrap_or_else(|| {
1195 Client::new(32).expect("failed to create jobserver")
1197 GLOBAL_JOBSERVER = Box::into_raw(Box::new(client));
1199 (*GLOBAL_JOBSERVER).clone()
1201 has_global_allocator: Once::new(),
1202 has_panic_handler: Once::new(),
1203 driver_lint_caps: FxHashMap(),
1206 validate_commandline_args_with_session_available(&sess);
1211 // If it is useful to have a Session available already for validating a
1212 // commandline argument, you can do so here.
1213 fn validate_commandline_args_with_session_available(sess: &Session) {
1215 if sess.opts.incremental.is_some() {
1219 sess.err("can't perform LTO when compiling incrementally");
1228 // Since we don't know if code in an rlib will be linked to statically or
1229 // dynamically downstream, rustc generates `__imp_` symbols that help the
1230 // MSVC linker deal with this lack of knowledge (#27438). Unfortunately,
1231 // these manually generated symbols confuse LLD when it tries to merge
1232 // bitcode during ThinLTO. Therefore we disallow dynamic linking on MSVC
1233 // when compiling for LLD ThinLTO. This way we can validly just not generate
1234 // the `dllimport` attributes and `__imp_` symbols in that case.
1235 if sess.opts.debugging_opts.cross_lang_lto.enabled() &&
1236 sess.opts.cg.prefer_dynamic &&
1237 sess.target.target.options.is_like_msvc {
1238 sess.err("Linker plugin based LTO is not supported together with \
1239 `-C prefer-dynamic` when targeting MSVC");
1243 /// Hash value constructed out of all the `-C metadata` arguments passed to the
1244 /// compiler. Together with the crate-name forms a unique global identifier for
1246 #[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy, RustcEncodable, RustcDecodable)]
1247 pub struct CrateDisambiguator(Fingerprint);
1249 impl CrateDisambiguator {
1250 pub fn to_fingerprint(self) -> Fingerprint {
1255 impl fmt::Display for CrateDisambiguator {
1256 fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
1257 let (a, b) = self.0.as_value();
1258 let as_u128 = a as u128 | ((b as u128) << 64);
1259 f.write_str(&base_n::encode(as_u128, base_n::CASE_INSENSITIVE))
1263 impl From<Fingerprint> for CrateDisambiguator {
1264 fn from(fingerprint: Fingerprint) -> CrateDisambiguator {
1265 CrateDisambiguator(fingerprint)
1269 impl_stable_hash_via_hash!(CrateDisambiguator);
1271 /// Holds data on the current incremental compilation session, if there is one.
1273 pub enum IncrCompSession {
1274 /// This is the state the session will be in until the incr. comp. dir is
1277 /// This is the state during which the session directory is private and can
1280 session_directory: PathBuf,
1281 lock_file: flock::Lock,
1282 load_dep_graph: bool,
1284 /// This is the state after the session directory has been finalized. In this
1285 /// state, the contents of the directory must not be modified any more.
1286 Finalized { session_directory: PathBuf },
1287 /// This is an error state that is reached when some compilation error has
1288 /// occurred. It indicates that the contents of the session directory must
1289 /// not be used, since they might be invalid.
1290 InvalidBecauseOfErrors { session_directory: PathBuf },
1293 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
1294 let emitter: Box<dyn Emitter + sync::Send> = match output {
1295 config::ErrorOutputType::HumanReadable(color_config) => {
1296 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1298 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1299 config::ErrorOutputType::Short(color_config) => {
1300 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1303 let handler = errors::Handler::with_emitter(true, false, emitter);
1304 handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal);
1305 errors::FatalError.raise();
1308 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
1309 let emitter: Box<dyn Emitter + sync::Send> = match output {
1310 config::ErrorOutputType::HumanReadable(color_config) => {
1311 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1313 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1314 config::ErrorOutputType::Short(color_config) => {
1315 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1318 let handler = errors::Handler::with_emitter(true, false, emitter);
1319 handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
1322 #[derive(Copy, Clone, Debug)]
1323 pub enum CompileIncomplete {
1325 Errored(ErrorReported),
1327 impl From<ErrorReported> for CompileIncomplete {
1328 fn from(err: ErrorReported) -> CompileIncomplete {
1329 CompileIncomplete::Errored(err)
1332 pub type CompileResult = Result<(), CompileIncomplete>;
1334 pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
1338 Err(CompileIncomplete::Errored(ErrorReported))