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::config::{OutputType, Lto};
23 use session::search_paths::{PathKind, SearchPath};
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 errors::{self, DiagnosticBuilder, DiagnosticId, Applicability};
32 use errors::emitter::{Emitter, EmitterWriter};
33 use syntax::ast::{self, NodeId};
34 use syntax::edition::Edition;
35 use syntax::feature_gate::{self, AttributeType};
36 use syntax::json::JsonEmitter;
37 use syntax::source_map;
38 use syntax::parse::{self, ParseSess};
39 use syntax_pos::{MultiSpan, Span};
40 use util::profiling::SelfProfiler;
42 use rustc_target::spec::{PanicStrategy, RelroLevel, Target, TargetTriple};
43 use rustc_data_structures::flock;
44 use jobserver::Client;
47 use std::cell::{self, Cell, RefCell};
51 use std::path::PathBuf;
52 use std::time::Duration;
54 use std::sync::atomic::{AtomicUsize, Ordering};
61 /// Represents the data associated with a compilation
62 /// session for a single crate.
64 pub target: config::Config,
66 pub opts: config::Options,
67 pub host_tlib_path: SearchPath,
68 /// This is `None` if the host and target are the same.
69 pub target_tlib_path: Option<SearchPath>,
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 proc_macro_decls_static: Once<Option<ast::NodeId>>,
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 allocator_kind: Once<Option<AllocatorKind>>,
119 pub injected_panic_runtime: Once<Option<CrateNum>>,
121 /// Map from imported macro spans (which consist of
122 /// the localized span for the macro body) to the
123 /// macro name and definition span in the source crate.
124 pub imported_macro_spans: OneThread<RefCell<FxHashMap<Span, (String, Span)>>>,
126 incr_comp_session: OneThread<RefCell<IncrCompSession>>,
127 /// Used for incremental compilation tests. Will only be populated if
128 /// `-Zquery-dep-graph` is specified.
129 pub cgu_reuse_tracker: CguReuseTracker,
131 /// Used by -Z profile-queries in util::common
132 pub profile_channel: Lock<Option<mpsc::Sender<ProfileQueriesMsg>>>,
134 /// Used by -Z self-profile
135 pub self_profiling: Lock<SelfProfiler>,
137 /// Some measurements that are being gathered during compilation.
138 pub perf_stats: PerfStats,
140 /// Data about code being compiled, gathered during compilation.
141 pub code_stats: Lock<CodeStats>,
143 next_node_id: OneThread<Cell<ast::NodeId>>,
145 /// If -zfuel=crate=n is specified, Some(crate).
146 optimization_fuel_crate: Option<String>,
147 /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0.
148 optimization_fuel_limit: LockCell<u64>,
149 /// We're rejecting all further optimizations.
150 out_of_fuel: LockCell<bool>,
152 // The next two are public because the driver needs to read them.
153 /// If -zprint-fuel=crate, Some(crate).
154 pub print_fuel_crate: Option<String>,
155 /// Always set to zero and incremented so that we can print fuel expended by a crate.
156 pub print_fuel: LockCell<u64>,
158 /// Loaded up early on in the initialization of this `Session` to avoid
159 /// false positives about a job server in our environment.
160 pub jobserver: Client,
162 /// Metadata about the allocators for the current crate being compiled
163 pub has_global_allocator: Once<bool>,
165 /// Metadata about the panic handlers for the current crate being compiled
166 pub has_panic_handler: Once<bool>,
168 /// Cap lint level specified by a driver specifically.
169 pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
172 pub struct PerfStats {
173 /// The accumulated time spent on computing symbol hashes
174 pub symbol_hash_time: Lock<Duration>,
175 /// The accumulated time spent decoding def path tables from metadata
176 pub decode_def_path_tables_time: Lock<Duration>,
177 /// Total number of values canonicalized queries constructed.
178 pub queries_canonicalized: AtomicUsize,
179 /// Number of times this query is invoked.
180 pub normalize_ty_after_erasing_regions: AtomicUsize,
181 /// Number of times this query is invoked.
182 pub normalize_projection_ty: AtomicUsize,
185 /// Enum to support dispatch of one-time diagnostics (in Session.diag_once)
186 enum DiagnosticBuilderMethod {
189 SpanSuggestion(String), // suggestion
190 // add more variants as needed to support one-time diagnostics
193 /// Diagnostic message ID—used by `Session.one_time_diagnostics` to avoid
194 /// emitting the same message more than once
195 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
196 pub enum DiagnosticMessageId {
197 ErrorId(u16), // EXXXX error code as integer
198 LintId(lint::LintId),
199 StabilityId(u32), // issue number
202 impl From<&'static lint::Lint> for DiagnosticMessageId {
203 fn from(lint: &'static lint::Lint) -> Self {
204 DiagnosticMessageId::LintId(lint::LintId::of(lint))
209 pub fn local_crate_disambiguator(&self) -> CrateDisambiguator {
210 *self.crate_disambiguator.get()
213 pub fn struct_span_warn<'a, S: Into<MultiSpan>>(
217 ) -> DiagnosticBuilder<'a> {
218 self.diagnostic().struct_span_warn(sp, msg)
220 pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(
225 ) -> DiagnosticBuilder<'a> {
226 self.diagnostic().struct_span_warn_with_code(sp, msg, code)
228 pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
229 self.diagnostic().struct_warn(msg)
231 pub fn struct_span_err<'a, S: Into<MultiSpan>>(
235 ) -> DiagnosticBuilder<'a> {
236 self.diagnostic().struct_span_err(sp, msg)
238 pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(
243 ) -> DiagnosticBuilder<'a> {
244 self.diagnostic().struct_span_err_with_code(sp, msg, code)
246 // FIXME: This method should be removed (every error should have an associated error code).
247 pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
248 self.diagnostic().struct_err(msg)
250 pub fn struct_err_with_code<'a>(
254 ) -> DiagnosticBuilder<'a> {
255 self.diagnostic().struct_err_with_code(msg, code)
257 pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(
261 ) -> DiagnosticBuilder<'a> {
262 self.diagnostic().struct_span_fatal(sp, msg)
264 pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(
269 ) -> DiagnosticBuilder<'a> {
270 self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
272 pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
273 self.diagnostic().struct_fatal(msg)
276 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
277 self.diagnostic().span_fatal(sp, msg).raise()
279 pub fn span_fatal_with_code<S: Into<MultiSpan>>(
286 .span_fatal_with_code(sp, msg, code)
289 pub fn fatal(&self, msg: &str) -> ! {
290 self.diagnostic().fatal(msg).raise()
292 pub fn span_err_or_warn<S: Into<MultiSpan>>(&self, is_warning: bool, sp: S, msg: &str) {
294 self.span_warn(sp, msg);
296 self.span_err(sp, msg);
299 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
300 self.diagnostic().span_err(sp, msg)
302 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
303 self.diagnostic().span_err_with_code(sp, &msg, code)
305 pub fn err(&self, msg: &str) {
306 self.diagnostic().err(msg)
308 pub fn err_count(&self) -> usize {
309 self.diagnostic().err_count()
311 pub fn has_errors(&self) -> bool {
312 self.diagnostic().has_errors()
314 pub fn abort_if_errors(&self) {
315 self.diagnostic().abort_if_errors();
317 pub fn compile_status(&self) -> Result<(), CompileIncomplete> {
318 compile_result_from_err_count(self.err_count())
320 pub fn track_errors<F, T>(&self, f: F) -> Result<T, ErrorReported>
324 let old_count = self.err_count();
326 let errors = self.err_count() - old_count;
333 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
334 self.diagnostic().span_warn(sp, msg)
336 pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
337 self.diagnostic().span_warn_with_code(sp, msg, code)
339 pub fn warn(&self, msg: &str) {
340 self.diagnostic().warn(msg)
342 pub fn opt_span_warn<S: Into<MultiSpan>>(&self, opt_sp: Option<S>, msg: &str) {
344 Some(sp) => self.span_warn(sp, msg),
345 None => self.warn(msg),
348 /// Delay a span_bug() call until abort_if_errors()
349 pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
350 self.diagnostic().delay_span_bug(sp, msg)
352 pub fn note_without_error(&self, msg: &str) {
353 self.diagnostic().note_without_error(msg)
355 pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
356 self.diagnostic().span_note_without_error(sp, msg)
358 pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
359 self.diagnostic().span_unimpl(sp, msg)
361 pub fn unimpl(&self, msg: &str) -> ! {
362 self.diagnostic().unimpl(msg)
365 pub fn buffer_lint<S: Into<MultiSpan>>(
367 lint: &'static lint::Lint,
372 match *self.buffered_lints.borrow_mut() {
373 Some(ref mut buffer) => {
374 buffer.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal)
376 None => bug!("can't buffer lints after HIR lowering"),
380 pub fn buffer_lint_with_diagnostic<S: Into<MultiSpan>>(
382 lint: &'static lint::Lint,
386 diagnostic: BuiltinLintDiagnostics,
388 match *self.buffered_lints.borrow_mut() {
389 Some(ref mut buffer) => buffer.add_lint(lint, id, sp.into(), msg, diagnostic),
390 None => bug!("can't buffer lints after HIR lowering"),
394 pub fn reserve_node_ids(&self, count: usize) -> ast::NodeId {
395 let id = self.next_node_id.get();
397 match id.as_usize().checked_add(count) {
399 self.next_node_id.set(ast::NodeId::from_usize(next));
401 None => bug!("Input too large, ran out of node ids!"),
406 pub fn next_node_id(&self) -> NodeId {
407 self.reserve_node_ids(1)
409 pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler {
410 &self.parse_sess.span_diagnostic
413 /// Analogous to calling methods on the given `DiagnosticBuilder`, but
414 /// deduplicates on lint ID, span (if any), and message for this `Session`
415 fn diag_once<'a, 'b>(
417 diag_builder: &'b mut DiagnosticBuilder<'a>,
418 method: DiagnosticBuilderMethod,
419 msg_id: DiagnosticMessageId,
421 span_maybe: Option<Span>,
423 let id_span_message = (msg_id, span_maybe, message.to_owned());
424 let fresh = self.one_time_diagnostics
426 .insert(id_span_message);
429 DiagnosticBuilderMethod::Note => {
430 diag_builder.note(message);
432 DiagnosticBuilderMethod::SpanNote => {
433 let span = span_maybe.expect("span_note needs a span");
434 diag_builder.span_note(span, message);
436 DiagnosticBuilderMethod::SpanSuggestion(suggestion) => {
437 let span = span_maybe.expect("span_suggestion_* needs a span");
438 diag_builder.span_suggestion_with_applicability(
442 Applicability::Unspecified,
449 pub fn diag_span_note_once<'a, 'b>(
451 diag_builder: &'b mut DiagnosticBuilder<'a>,
452 msg_id: DiagnosticMessageId,
458 DiagnosticBuilderMethod::SpanNote,
465 pub fn diag_note_once<'a, 'b>(
467 diag_builder: &'b mut DiagnosticBuilder<'a>,
468 msg_id: DiagnosticMessageId,
473 DiagnosticBuilderMethod::Note,
480 pub fn diag_span_suggestion_once<'a, 'b>(
482 diag_builder: &'b mut DiagnosticBuilder<'a>,
483 msg_id: DiagnosticMessageId,
490 DiagnosticBuilderMethod::SpanSuggestion(suggestion),
497 pub fn source_map<'a>(&'a self) -> &'a source_map::SourceMap {
498 self.parse_sess.source_map()
500 pub fn verbose(&self) -> bool {
501 self.opts.debugging_opts.verbose
503 pub fn time_passes(&self) -> bool {
504 self.opts.debugging_opts.time_passes
506 pub fn profile_queries(&self) -> bool {
507 self.opts.debugging_opts.profile_queries
508 || self.opts.debugging_opts.profile_queries_and_keys
510 pub fn profile_queries_and_keys(&self) -> bool {
511 self.opts.debugging_opts.profile_queries_and_keys
513 pub fn count_llvm_insns(&self) -> bool {
514 self.opts.debugging_opts.count_llvm_insns
516 pub fn time_llvm_passes(&self) -> bool {
517 self.opts.debugging_opts.time_llvm_passes
519 pub fn codegen_stats(&self) -> bool {
520 self.opts.debugging_opts.codegen_stats
522 pub fn meta_stats(&self) -> bool {
523 self.opts.debugging_opts.meta_stats
525 pub fn asm_comments(&self) -> bool {
526 self.opts.debugging_opts.asm_comments
528 pub fn verify_llvm_ir(&self) -> bool {
529 self.opts.debugging_opts.verify_llvm_ir
530 || cfg!(always_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_proc_macro_decls_symbol(&self, disambiguator: CrateDisambiguator) -> String {
695 "__rustc_proc_macro_decls_{}__",
696 disambiguator.to_fingerprint().to_hex()
700 pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
701 filesearch::FileSearch::new(
703 self.opts.target_triple.triple(),
704 &self.opts.search_paths,
705 // target_tlib_path==None means it's the same as host_tlib_path.
706 self.target_tlib_path.as_ref().unwrap_or(&self.host_tlib_path),
710 pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
711 filesearch::FileSearch::new(
713 config::host_triple(),
714 &self.opts.search_paths,
715 &self.host_tlib_path,
720 pub fn set_incr_session_load_dep_graph(&self, load: bool) {
721 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
723 if let IncrCompSession::Active { ref mut load_dep_graph, .. } = *incr_comp_session {
724 *load_dep_graph = load;
728 pub fn incr_session_load_dep_graph(&self) -> bool {
729 let incr_comp_session = self.incr_comp_session.borrow();
730 match *incr_comp_session {
731 IncrCompSession::Active { load_dep_graph, .. } => load_dep_graph,
736 pub fn init_incr_comp_session(
738 session_dir: PathBuf,
739 lock_file: flock::Lock,
740 load_dep_graph: bool,
742 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
744 if let IncrCompSession::NotInitialized = *incr_comp_session {
747 "Trying to initialize IncrCompSession `{:?}`",
752 *incr_comp_session = IncrCompSession::Active {
753 session_directory: session_dir,
759 pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) {
760 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
762 if let IncrCompSession::Active { .. } = *incr_comp_session {
765 "Trying to finalize IncrCompSession `{:?}`",
770 // Note: This will also drop the lock file, thus unlocking the directory
771 *incr_comp_session = IncrCompSession::Finalized {
772 session_directory: new_directory_path,
776 pub fn mark_incr_comp_session_as_invalid(&self) {
777 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
779 let session_directory = match *incr_comp_session {
780 IncrCompSession::Active {
781 ref session_directory,
783 } => session_directory.clone(),
784 IncrCompSession::InvalidBecauseOfErrors { .. } => return,
786 "Trying to invalidate IncrCompSession `{:?}`",
791 // Note: This will also drop the lock file, thus unlocking the directory
792 *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors { session_directory };
795 pub fn incr_comp_session_dir(&self) -> cell::Ref<'_, PathBuf> {
796 let incr_comp_session = self.incr_comp_session.borrow();
799 |incr_comp_session| match *incr_comp_session {
800 IncrCompSession::NotInitialized => bug!(
801 "Trying to get session directory from IncrCompSession `{:?}`",
804 IncrCompSession::Active {
805 ref session_directory,
808 | IncrCompSession::Finalized {
809 ref session_directory,
811 | IncrCompSession::InvalidBecauseOfErrors {
812 ref session_directory,
813 } => session_directory,
818 pub fn incr_comp_session_dir_opt(&self) -> Option<cell::Ref<'_, PathBuf>> {
819 if self.opts.incremental.is_some() {
820 Some(self.incr_comp_session_dir())
826 pub fn profiler<F: FnOnce(&mut SelfProfiler) -> ()>(&self, f: F) {
827 if self.opts.debugging_opts.self_profile || self.opts.debugging_opts.profile_json {
828 let mut profiler = self.self_profiling.borrow_mut();
833 pub fn print_profiler_results(&self) {
834 let mut profiler = self.self_profiling.borrow_mut();
835 profiler.print_results(&self.opts);
838 pub fn save_json_results(&self) {
839 let profiler = self.self_profiling.borrow();
840 profiler.save_results(&self.opts);
843 pub fn print_perf_stats(&self) {
845 "Total time spent computing symbol hashes: {}",
846 duration_to_secs_str(*self.perf_stats.symbol_hash_time.lock())
849 "Total time spent decoding DefPath tables: {}",
850 duration_to_secs_str(*self.perf_stats.decode_def_path_tables_time.lock())
852 println!("Total queries canonicalized: {}",
853 self.perf_stats.queries_canonicalized.load(Ordering::Relaxed));
854 println!("normalize_ty_after_erasing_regions: {}",
855 self.perf_stats.normalize_ty_after_erasing_regions.load(Ordering::Relaxed));
856 println!("normalize_projection_ty: {}",
857 self.perf_stats.normalize_projection_ty.load(Ordering::Relaxed));
860 /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
861 /// This expends fuel if applicable, and records fuel if applicable.
862 pub fn consider_optimizing<T: Fn() -> String>(&self, crate_name: &str, msg: T) -> bool {
864 if let Some(ref c) = self.optimization_fuel_crate {
866 assert_eq!(self.query_threads(), 1);
867 let fuel = self.optimization_fuel_limit.get();
869 if fuel == 0 && !self.out_of_fuel.get() {
870 eprintln!("optimization-fuel-exhausted: {}", msg());
871 self.out_of_fuel.set(true);
873 self.optimization_fuel_limit.set(fuel - 1);
877 if let Some(ref c) = self.print_fuel_crate {
879 assert_eq!(self.query_threads(), 1);
880 self.print_fuel.set(self.print_fuel.get() + 1);
886 /// Returns the number of query threads that should be used for this
888 pub fn query_threads_from_opts(opts: &config::Options) -> usize {
889 opts.debugging_opts.query_threads.unwrap_or(1)
892 /// Returns the number of query threads that should be used for this
894 pub fn query_threads(&self) -> usize {
895 Self::query_threads_from_opts(&self.opts)
898 /// Returns the number of codegen units that should be used for this
900 pub fn codegen_units(&self) -> usize {
901 if let Some(n) = self.opts.cli_forced_codegen_units {
904 if let Some(n) = self.target.target.options.default_codegen_units {
908 // Why is 16 codegen units the default all the time?
910 // The main reason for enabling multiple codegen units by default is to
911 // leverage the ability for the codegen backend to do codegen and
912 // optimization in parallel. This allows us, especially for large crates, to
913 // make good use of all available resources on the machine once we've
914 // hit that stage of compilation. Large crates especially then often
915 // take a long time in codegen/optimization and this helps us amortize that
918 // Note that a high number here doesn't mean that we'll be spawning a
919 // large number of threads in parallel. The backend of rustc contains
920 // global rate limiting through the `jobserver` crate so we'll never
921 // overload the system with too much work, but rather we'll only be
922 // optimizing when we're otherwise cooperating with other instances of
925 // Rather a high number here means that we should be able to keep a lot
926 // of idle cpus busy. By ensuring that no codegen unit takes *too* long
927 // to build we'll be guaranteed that all cpus will finish pretty closely
928 // to one another and we should make relatively optimal use of system
931 // Note that the main cost of codegen units is that it prevents LLVM
932 // from inlining across codegen units. Users in general don't have a lot
933 // of control over how codegen units are split up so it's our job in the
934 // compiler to ensure that undue performance isn't lost when using
935 // codegen units (aka we can't require everyone to slap `#[inline]` on
938 // If we're compiling at `-O0` then the number doesn't really matter too
939 // much because performance doesn't matter and inlining is ok to lose.
940 // In debug mode we just want to try to guarantee that no cpu is stuck
941 // doing work that could otherwise be farmed to others.
943 // In release mode, however (O1 and above) performance does indeed
944 // matter! To recover the loss in performance due to inlining we'll be
945 // enabling ThinLTO by default (the function for which is just below).
946 // This will ensure that we recover any inlining wins we otherwise lost
947 // through codegen unit partitioning.
951 // Ok that's a lot of words but the basic tl;dr; is that we want a high
952 // number here -- but not too high. Additionally we're "safe" to have it
953 // always at the same number at all optimization levels.
955 // As a result 16 was chosen here! Mostly because it was a power of 2
956 // and most benchmarks agreed it was roughly a local optimum. Not very
961 pub fn teach(&self, code: &DiagnosticId) -> bool {
962 self.opts.debugging_opts.teach && self.diagnostic().must_teach(code)
965 pub fn rust_2015(&self) -> bool {
966 self.opts.edition == Edition::Edition2015
969 /// Are we allowed to use features from the Rust 2018 edition?
970 pub fn rust_2018(&self) -> bool {
971 self.opts.edition >= Edition::Edition2018
974 pub fn edition(&self) -> Edition {
978 /// True if we cannot skip the PLT for shared library calls.
979 pub fn needs_plt(&self) -> bool {
980 // Check if the current target usually needs PLT to be enabled.
981 // The user can use the command line flag to override it.
982 let needs_plt = self.target.target.options.needs_plt;
984 let dbg_opts = &self.opts.debugging_opts;
986 let relro_level = dbg_opts.relro_level
987 .unwrap_or(self.target.target.options.relro_level);
989 // Only enable this optimization by default if full relro is also enabled.
990 // In this case, lazy binding was already unavailable, so nothing is lost.
991 // This also ensures `-Wl,-z,now` is supported by the linker.
992 let full_relro = RelroLevel::Full == relro_level;
994 // If user didn't explicitly forced us to use / skip the PLT,
995 // then try to skip it where possible.
996 dbg_opts.plt.unwrap_or(needs_plt || !full_relro)
1000 pub fn build_session(
1001 sopts: config::Options,
1002 local_crate_source_file: Option<PathBuf>,
1003 registry: errors::registry::Registry,
1005 let file_path_mapping = sopts.file_path_mapping();
1007 build_session_with_source_map(
1009 local_crate_source_file,
1011 Lrc::new(source_map::SourceMap::new(file_path_mapping)),
1016 pub fn build_session_with_source_map(
1017 sopts: config::Options,
1018 local_crate_source_file: Option<PathBuf>,
1019 registry: errors::registry::Registry,
1020 source_map: Lrc<source_map::SourceMap>,
1021 emitter_dest: Option<Box<dyn Write + Send>>,
1023 // FIXME: This is not general enough to make the warning lint completely override
1024 // normal diagnostic warnings, since the warning lint can also be denied and changed
1025 // later via the source code.
1026 let warnings_allow = sopts
1029 .filter(|&&(ref key, _)| *key == "warnings")
1030 .map(|&(_, ref level)| *level == lint::Allow)
1033 let cap_lints_allow = sopts.lint_cap.map_or(false, |cap| cap == lint::Allow);
1035 let can_emit_warnings = !(warnings_allow || cap_lints_allow);
1037 let treat_err_as_bug = sopts.debugging_opts.treat_err_as_bug;
1038 let dont_buffer_diagnostics = sopts.debugging_opts.dont_buffer_diagnostics;
1039 let report_delayed_bugs = sopts.debugging_opts.report_delayed_bugs;
1041 let external_macro_backtrace = sopts.debugging_opts.external_macro_backtrace;
1043 let emitter: Box<dyn Emitter + sync::Send> =
1044 match (sopts.error_format, emitter_dest) {
1045 (config::ErrorOutputType::HumanReadable(color_config), None) => Box::new(
1046 EmitterWriter::stderr(
1048 Some(source_map.clone()),
1050 sopts.debugging_opts.teach,
1051 ).ui_testing(sopts.debugging_opts.ui_testing),
1053 (config::ErrorOutputType::HumanReadable(_), Some(dst)) => Box::new(
1054 EmitterWriter::new(dst, Some(source_map.clone()), false, false)
1055 .ui_testing(sopts.debugging_opts.ui_testing),
1057 (config::ErrorOutputType::Json(pretty), None) => Box::new(
1058 JsonEmitter::stderr(
1062 ).ui_testing(sopts.debugging_opts.ui_testing),
1064 (config::ErrorOutputType::Json(pretty), Some(dst)) => Box::new(
1070 ).ui_testing(sopts.debugging_opts.ui_testing),
1072 (config::ErrorOutputType::Short(color_config), None) => Box::new(
1073 EmitterWriter::stderr(color_config, Some(source_map.clone()), true, false),
1075 (config::ErrorOutputType::Short(_), Some(dst)) => {
1076 Box::new(EmitterWriter::new(dst, Some(source_map.clone()), true, false))
1080 let diagnostic_handler = errors::Handler::with_emitter_and_flags(
1082 errors::HandlerFlags {
1085 report_delayed_bugs,
1086 dont_buffer_diagnostics,
1087 external_macro_backtrace,
1088 ..Default::default()
1092 build_session_(sopts, local_crate_source_file, diagnostic_handler, source_map)
1095 pub fn build_session_(
1096 sopts: config::Options,
1097 local_crate_source_file: Option<PathBuf>,
1098 span_diagnostic: errors::Handler,
1099 source_map: Lrc<source_map::SourceMap>,
1101 let host_triple = TargetTriple::from_triple(config::host_triple());
1102 let host = Target::search(&host_triple).unwrap_or_else(|e|
1104 .fatal(&format!("Error loading host specification: {}", e))
1107 let target_cfg = config::build_target_config(&sopts, &span_diagnostic);
1109 let p_s = parse::ParseSess::with_span_handler(span_diagnostic, source_map);
1110 let sysroot = match &sopts.maybe_sysroot {
1111 Some(sysroot) => sysroot.clone(),
1112 None => filesearch::get_or_default_sysroot(),
1115 let host_triple = config::host_triple();
1116 let target_triple = sopts.target_triple.triple();
1117 let host_tlib_path = SearchPath::from_sysroot_and_triple(&sysroot, host_triple);
1118 let target_tlib_path = if host_triple == target_triple {
1121 Some(SearchPath::from_sysroot_and_triple(&sysroot, target_triple))
1124 let file_path_mapping = sopts.file_path_mapping();
1126 let local_crate_source_file =
1127 local_crate_source_file.map(|path| file_path_mapping.map_prefix(path).0);
1129 let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone());
1130 let optimization_fuel_limit =
1131 LockCell::new(sopts.debugging_opts.fuel.as_ref().map(|i| i.1).unwrap_or(0));
1132 let print_fuel_crate = sopts.debugging_opts.print_fuel.clone();
1133 let print_fuel = LockCell::new(0);
1135 let working_dir = env::current_dir().unwrap_or_else(|e|
1137 .fatal(&format!("Current directory is invalid: {}", e))
1140 let working_dir = file_path_mapping.map_prefix(working_dir);
1142 let cgu_reuse_tracker = if sopts.debugging_opts.query_dep_graph {
1143 CguReuseTracker::new()
1145 CguReuseTracker::new_disabled()
1148 let sess = Session {
1155 // For a library crate, this is always none
1156 entry_fn: Once::new(),
1157 plugin_registrar_fn: Once::new(),
1158 proc_macro_decls_static: Once::new(),
1160 local_crate_source_file,
1162 lint_store: RwLock::new(lint::LintStore::new()),
1163 buffered_lints: Lock::new(Some(Default::default())),
1164 one_time_diagnostics: Default::default(),
1165 plugin_llvm_passes: OneThread::new(RefCell::new(Vec::new())),
1166 plugin_attributes: OneThread::new(RefCell::new(Vec::new())),
1167 crate_types: Once::new(),
1168 dependency_formats: Once::new(),
1169 crate_disambiguator: Once::new(),
1170 features: Once::new(),
1171 recursion_limit: Once::new(),
1172 type_length_limit: Once::new(),
1173 const_eval_stack_frame_limit: 100,
1174 next_node_id: OneThread::new(Cell::new(NodeId::from_u32(1))),
1175 allocator_kind: Once::new(),
1176 injected_panic_runtime: Once::new(),
1177 imported_macro_spans: OneThread::new(RefCell::new(FxHashMap::default())),
1178 incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)),
1180 self_profiling: Lock::new(SelfProfiler::new()),
1181 profile_channel: Lock::new(None),
1182 perf_stats: PerfStats {
1183 symbol_hash_time: Lock::new(Duration::from_secs(0)),
1184 decode_def_path_tables_time: Lock::new(Duration::from_secs(0)),
1185 queries_canonicalized: AtomicUsize::new(0),
1186 normalize_ty_after_erasing_regions: AtomicUsize::new(0),
1187 normalize_projection_ty: AtomicUsize::new(0),
1189 code_stats: Default::default(),
1190 optimization_fuel_crate,
1191 optimization_fuel_limit,
1194 out_of_fuel: LockCell::new(false),
1195 // Note that this is unsafe because it may misinterpret file descriptors
1196 // on Unix as jobserver file descriptors. We hopefully execute this near
1197 // the beginning of the process though to ensure we don't get false
1198 // positives, or in other words we try to execute this before we open
1199 // any file descriptors ourselves.
1201 // Pick a "reasonable maximum" if we don't otherwise have
1202 // a jobserver in our environment, capping out at 32 so we
1203 // don't take everything down by hogging the process run queue.
1204 // The fixed number is used to have deterministic compilation
1207 // Also note that we stick this in a global because there could be
1208 // multiple `Session` instances in this process, and the jobserver is
1211 static mut GLOBAL_JOBSERVER: *mut Client = 0 as *mut _;
1212 static INIT: std::sync::Once = std::sync::ONCE_INIT;
1214 let client = Client::from_env().unwrap_or_else(|| {
1215 Client::new(32).expect("failed to create jobserver")
1217 GLOBAL_JOBSERVER = Box::into_raw(Box::new(client));
1219 (*GLOBAL_JOBSERVER).clone()
1221 has_global_allocator: Once::new(),
1222 has_panic_handler: Once::new(),
1223 driver_lint_caps: Default::default(),
1226 validate_commandline_args_with_session_available(&sess);
1231 // If it is useful to have a Session available already for validating a
1232 // commandline argument, you can do so here.
1233 fn validate_commandline_args_with_session_available(sess: &Session) {
1235 if sess.opts.incremental.is_some() {
1239 sess.err("can't perform LTO when compiling incrementally");
1248 // Since we don't know if code in an rlib will be linked to statically or
1249 // dynamically downstream, rustc generates `__imp_` symbols that help the
1250 // MSVC linker deal with this lack of knowledge (#27438). Unfortunately,
1251 // these manually generated symbols confuse LLD when it tries to merge
1252 // bitcode during ThinLTO. Therefore we disallow dynamic linking on MSVC
1253 // when compiling for LLD ThinLTO. This way we can validly just not generate
1254 // the `dllimport` attributes and `__imp_` symbols in that case.
1255 if sess.opts.debugging_opts.cross_lang_lto.enabled() &&
1256 sess.opts.cg.prefer_dynamic &&
1257 sess.target.target.options.is_like_msvc {
1258 sess.err("Linker plugin based LTO is not supported together with \
1259 `-C prefer-dynamic` when targeting MSVC");
1263 /// Hash value constructed out of all the `-C metadata` arguments passed to the
1264 /// compiler. Together with the crate-name forms a unique global identifier for
1266 #[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy, RustcEncodable, RustcDecodable)]
1267 pub struct CrateDisambiguator(Fingerprint);
1269 impl CrateDisambiguator {
1270 pub fn to_fingerprint(self) -> Fingerprint {
1275 impl fmt::Display for CrateDisambiguator {
1276 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
1277 let (a, b) = self.0.as_value();
1278 let as_u128 = a as u128 | ((b as u128) << 64);
1279 f.write_str(&base_n::encode(as_u128, base_n::CASE_INSENSITIVE))
1283 impl From<Fingerprint> for CrateDisambiguator {
1284 fn from(fingerprint: Fingerprint) -> CrateDisambiguator {
1285 CrateDisambiguator(fingerprint)
1289 impl_stable_hash_via_hash!(CrateDisambiguator);
1291 /// Holds data on the current incremental compilation session, if there is one.
1293 pub enum IncrCompSession {
1294 /// This is the state the session will be in until the incr. comp. dir is
1297 /// This is the state during which the session directory is private and can
1300 session_directory: PathBuf,
1301 lock_file: flock::Lock,
1302 load_dep_graph: bool,
1304 /// This is the state after the session directory has been finalized. In this
1305 /// state, the contents of the directory must not be modified any more.
1306 Finalized { session_directory: PathBuf },
1307 /// This is an error state that is reached when some compilation error has
1308 /// occurred. It indicates that the contents of the session directory must
1309 /// not be used, since they might be invalid.
1310 InvalidBecauseOfErrors { session_directory: PathBuf },
1313 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
1314 let emitter: Box<dyn Emitter + sync::Send> = match output {
1315 config::ErrorOutputType::HumanReadable(color_config) => {
1316 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1318 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1319 config::ErrorOutputType::Short(color_config) => {
1320 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1323 let handler = errors::Handler::with_emitter(true, false, emitter);
1324 handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal);
1325 errors::FatalError.raise();
1328 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
1329 let emitter: Box<dyn Emitter + sync::Send> = match output {
1330 config::ErrorOutputType::HumanReadable(color_config) => {
1331 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1333 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1334 config::ErrorOutputType::Short(color_config) => {
1335 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1338 let handler = errors::Handler::with_emitter(true, false, emitter);
1339 handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
1342 #[derive(Copy, Clone, Debug)]
1343 pub enum CompileIncomplete {
1345 Errored(ErrorReported),
1347 impl From<ErrorReported> for CompileIncomplete {
1348 fn from(err: ErrorReported) -> CompileIncomplete {
1349 CompileIncomplete::Errored(err)
1352 pub type CompileResult = Result<(), CompileIncomplete>;
1354 pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
1358 Err(CompileIncomplete::Errored(ErrorReported))