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 hir::def_id::CrateNum;
15 use rustc_data_structures::fingerprint::Fingerprint;
18 use lint::builtin::BuiltinLintDiagnostics;
19 use middle::allocator::AllocatorKind;
20 use middle::dependency_format;
21 use session::search_paths::PathKind;
22 use session::config::{OutputType, Lto};
23 use util::nodemap::{FxHashMap, FxHashSet};
24 use util::common::{duration_to_secs_str, ErrorReported};
25 use util::common::ProfileQueriesMsg;
27 use rustc_data_structures::base_n;
28 use rustc_data_structures::sync::{self, Lrc, Lock, LockCell, OneThread, Once, RwLock};
30 use syntax::ast::NodeId;
31 use errors::{self, DiagnosticBuilder, DiagnosticId, Applicability};
32 use errors::emitter::{Emitter, EmitterWriter};
33 use syntax::edition::Edition;
34 use syntax::json::JsonEmitter;
35 use syntax::feature_gate;
37 use syntax::parse::ParseSess;
38 use syntax::{ast, source_map};
39 use syntax::feature_gate::AttributeType;
40 use syntax_pos::{MultiSpan, Span};
41 use util::profiling::SelfProfiler;
43 use rustc_target::spec::PanicStrategy;
44 use rustc_target::spec::{Target, TargetTriple};
45 use rustc_data_structures::flock;
46 use jobserver::Client;
49 use std::cell::{self, Cell, RefCell};
53 use std::path::{Path, PathBuf};
54 use std::time::Duration;
56 use std::sync::atomic::{AtomicUsize, Ordering};
63 /// Represents the data associated with a compilation
64 /// session for a single crate.
66 pub target: config::Config,
68 pub opts: config::Options,
69 pub parse_sess: ParseSess,
70 /// For a library crate, this is always none
71 pub entry_fn: Once<Option<(NodeId, Span, config::EntryFnType)>>,
72 pub plugin_registrar_fn: Once<Option<ast::NodeId>>,
73 pub derive_registrar_fn: Once<Option<ast::NodeId>>,
74 pub default_sysroot: Option<PathBuf>,
75 /// The name of the root source file of the crate, in the local file system.
76 /// `None` means that there is no source file.
77 pub local_crate_source_file: Option<PathBuf>,
78 /// The directory the compiler has been executed in plus a flag indicating
79 /// if the value stored here has been affected by path remapping.
80 pub working_dir: (PathBuf, bool),
82 // FIXME: lint_store and buffered_lints are not thread-safe,
83 // but are only used in a single thread
84 pub lint_store: RwLock<lint::LintStore>,
85 pub buffered_lints: Lock<Option<lint::LintBuffer>>,
87 /// Set of (DiagnosticId, Option<Span>, message) tuples tracking
88 /// (sub)diagnostics that have been set once, but should not be set again,
89 /// in order to avoid redundantly verbose output (Issue #24690, #44953).
90 pub one_time_diagnostics: Lock<FxHashSet<(DiagnosticMessageId, Option<Span>, String)>>,
91 pub plugin_llvm_passes: OneThread<RefCell<Vec<String>>>,
92 pub plugin_attributes: OneThread<RefCell<Vec<(String, AttributeType)>>>,
93 pub crate_types: Once<Vec<config::CrateType>>,
94 pub dependency_formats: Once<dependency_format::Dependencies>,
95 /// The crate_disambiguator is constructed out of all the `-C metadata`
96 /// arguments passed to the compiler. Its value together with the crate-name
97 /// forms a unique global identifier for the crate. It is used to allow
98 /// multiple crates with the same name to coexist. See the
99 /// rustc_codegen_llvm::back::symbol_names module for more information.
100 pub crate_disambiguator: Once<CrateDisambiguator>,
102 features: Once<feature_gate::Features>,
104 /// The maximum recursion limit for potentially infinitely recursive
105 /// operations such as auto-dereference and monomorphization.
106 pub recursion_limit: Once<usize>,
108 /// The maximum length of types during monomorphization.
109 pub type_length_limit: Once<usize>,
111 /// The maximum number of stackframes allowed in const eval
112 pub const_eval_stack_frame_limit: usize,
114 /// The metadata::creader module may inject an allocator/panic_runtime
115 /// dependency if it didn't already find one, and this tracks what was
117 pub injected_allocator: Once<Option<CrateNum>>,
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>>,
128 /// Used by -Z profile-queries in util::common
129 pub profile_channel: Lock<Option<mpsc::Sender<ProfileQueriesMsg>>>,
131 /// Used by -Z self-profile
132 pub self_profiling: Lock<SelfProfiler>,
134 /// Some measurements that are being gathered during compilation.
135 pub perf_stats: PerfStats,
137 /// Data about code being compiled, gathered during compilation.
138 pub code_stats: Lock<CodeStats>,
140 next_node_id: OneThread<Cell<ast::NodeId>>,
142 /// If -zfuel=crate=n is specified, Some(crate).
143 optimization_fuel_crate: Option<String>,
144 /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0.
145 optimization_fuel_limit: LockCell<u64>,
146 /// We're rejecting all further optimizations.
147 out_of_fuel: LockCell<bool>,
149 // The next two are public because the driver needs to read them.
150 /// If -zprint-fuel=crate, Some(crate).
151 pub print_fuel_crate: Option<String>,
152 /// Always set to zero and incremented so that we can print fuel expended by a crate.
153 pub print_fuel: LockCell<u64>,
155 /// Loaded up early on in the initialization of this `Session` to avoid
156 /// false positives about a job server in our environment.
157 pub jobserver: Client,
159 /// Metadata about the allocators for the current crate being compiled
160 pub has_global_allocator: Once<bool>,
162 /// Metadata about the panic handlers for the current crate being compiled
163 pub has_panic_handler: Once<bool>,
165 /// Cap lint level specified by a driver specifically.
166 pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
169 pub struct PerfStats {
170 /// The accumulated time spent on computing symbol hashes
171 pub symbol_hash_time: Lock<Duration>,
172 /// The accumulated time spent decoding def path tables from metadata
173 pub decode_def_path_tables_time: Lock<Duration>,
174 /// Total number of values canonicalized queries constructed.
175 pub queries_canonicalized: AtomicUsize,
176 /// Number of times this query is invoked.
177 pub normalize_ty_after_erasing_regions: AtomicUsize,
178 /// Number of times this query is invoked.
179 pub normalize_projection_ty: AtomicUsize,
182 /// Enum to support dispatch of one-time diagnostics (in Session.diag_once)
183 enum DiagnosticBuilderMethod {
186 SpanSuggestion(String), // suggestion
187 // add more variants as needed to support one-time diagnostics
190 /// Diagnostic message ID—used by `Session.one_time_diagnostics` to avoid
191 /// emitting the same message more than once
192 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
193 pub enum DiagnosticMessageId {
194 ErrorId(u16), // EXXXX error code as integer
195 LintId(lint::LintId),
196 StabilityId(u32), // issue number
199 impl From<&'static lint::Lint> for DiagnosticMessageId {
200 fn from(lint: &'static lint::Lint) -> Self {
201 DiagnosticMessageId::LintId(lint::LintId::of(lint))
206 pub fn local_crate_disambiguator(&self) -> CrateDisambiguator {
207 *self.crate_disambiguator.get()
210 pub fn struct_span_warn<'a, S: Into<MultiSpan>>(
214 ) -> DiagnosticBuilder<'a> {
215 self.diagnostic().struct_span_warn(sp, msg)
217 pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(
222 ) -> DiagnosticBuilder<'a> {
223 self.diagnostic().struct_span_warn_with_code(sp, msg, code)
225 pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
226 self.diagnostic().struct_warn(msg)
228 pub fn struct_span_err<'a, S: Into<MultiSpan>>(
232 ) -> DiagnosticBuilder<'a> {
233 self.diagnostic().struct_span_err(sp, msg)
235 pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(
240 ) -> DiagnosticBuilder<'a> {
241 self.diagnostic().struct_span_err_with_code(sp, msg, code)
243 // FIXME: This method should be removed (every error should have an associated error code).
244 pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
245 self.diagnostic().struct_err(msg)
247 pub fn struct_err_with_code<'a>(
251 ) -> DiagnosticBuilder<'a> {
252 self.diagnostic().struct_err_with_code(msg, code)
254 pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(
258 ) -> DiagnosticBuilder<'a> {
259 self.diagnostic().struct_span_fatal(sp, msg)
261 pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(
266 ) -> DiagnosticBuilder<'a> {
267 self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
269 pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
270 self.diagnostic().struct_fatal(msg)
273 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
274 self.diagnostic().span_fatal(sp, msg).raise()
276 pub fn span_fatal_with_code<S: Into<MultiSpan>>(
283 .span_fatal_with_code(sp, msg, code)
286 pub fn fatal(&self, msg: &str) -> ! {
287 self.diagnostic().fatal(msg).raise()
289 pub fn span_err_or_warn<S: Into<MultiSpan>>(&self, is_warning: bool, sp: S, msg: &str) {
291 self.span_warn(sp, msg);
293 self.span_err(sp, msg);
296 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
297 self.diagnostic().span_err(sp, msg)
299 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
300 self.diagnostic().span_err_with_code(sp, &msg, code)
302 pub fn err(&self, msg: &str) {
303 self.diagnostic().err(msg)
305 pub fn err_count(&self) -> usize {
306 self.diagnostic().err_count()
308 pub fn has_errors(&self) -> bool {
309 self.diagnostic().has_errors()
311 pub fn abort_if_errors(&self) {
312 self.diagnostic().abort_if_errors();
314 pub fn compile_status(&self) -> Result<(), CompileIncomplete> {
315 compile_result_from_err_count(self.err_count())
317 pub fn track_errors<F, T>(&self, f: F) -> Result<T, ErrorReported>
321 let old_count = self.err_count();
323 let errors = self.err_count() - old_count;
330 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
331 self.diagnostic().span_warn(sp, msg)
333 pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
334 self.diagnostic().span_warn_with_code(sp, msg, code)
336 pub fn warn(&self, msg: &str) {
337 self.diagnostic().warn(msg)
339 pub fn opt_span_warn<S: Into<MultiSpan>>(&self, opt_sp: Option<S>, msg: &str) {
341 Some(sp) => self.span_warn(sp, msg),
342 None => self.warn(msg),
345 /// Delay a span_bug() call until abort_if_errors()
346 pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
347 self.diagnostic().delay_span_bug(sp, msg)
349 pub fn note_without_error(&self, msg: &str) {
350 self.diagnostic().note_without_error(msg)
352 pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
353 self.diagnostic().span_note_without_error(sp, msg)
355 pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
356 self.diagnostic().span_unimpl(sp, msg)
358 pub fn unimpl(&self, msg: &str) -> ! {
359 self.diagnostic().unimpl(msg)
362 pub fn buffer_lint<S: Into<MultiSpan>>(
364 lint: &'static lint::Lint,
369 match *self.buffered_lints.borrow_mut() {
370 Some(ref mut buffer) => {
371 buffer.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal)
373 None => bug!("can't buffer lints after HIR lowering"),
377 pub fn buffer_lint_with_diagnostic<S: Into<MultiSpan>>(
379 lint: &'static lint::Lint,
383 diagnostic: BuiltinLintDiagnostics,
385 match *self.buffered_lints.borrow_mut() {
386 Some(ref mut buffer) => buffer.add_lint(lint, id, sp.into(), msg, diagnostic),
387 None => bug!("can't buffer lints after HIR lowering"),
391 pub fn reserve_node_ids(&self, count: usize) -> ast::NodeId {
392 let id = self.next_node_id.get();
394 match id.as_usize().checked_add(count) {
396 self.next_node_id.set(ast::NodeId::new(next));
398 None => bug!("Input too large, ran out of node ids!"),
403 pub fn next_node_id(&self) -> NodeId {
404 self.reserve_node_ids(1)
406 pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler {
407 &self.parse_sess.span_diagnostic
410 /// Analogous to calling methods on the given `DiagnosticBuilder`, but
411 /// deduplicates on lint ID, span (if any), and message for this `Session`
412 fn diag_once<'a, 'b>(
414 diag_builder: &'b mut DiagnosticBuilder<'a>,
415 method: DiagnosticBuilderMethod,
416 msg_id: DiagnosticMessageId,
418 span_maybe: Option<Span>,
420 let id_span_message = (msg_id, span_maybe, message.to_owned());
421 let fresh = self.one_time_diagnostics
423 .insert(id_span_message);
426 DiagnosticBuilderMethod::Note => {
427 diag_builder.note(message);
429 DiagnosticBuilderMethod::SpanNote => {
430 let span = span_maybe.expect("span_note needs a span");
431 diag_builder.span_note(span, message);
433 DiagnosticBuilderMethod::SpanSuggestion(suggestion) => {
434 let span = span_maybe.expect("span_suggestion_* needs a span");
435 diag_builder.span_suggestion_with_applicability(
439 Applicability::Unspecified,
446 pub fn diag_span_note_once<'a, 'b>(
448 diag_builder: &'b mut DiagnosticBuilder<'a>,
449 msg_id: DiagnosticMessageId,
455 DiagnosticBuilderMethod::SpanNote,
462 pub fn diag_note_once<'a, 'b>(
464 diag_builder: &'b mut DiagnosticBuilder<'a>,
465 msg_id: DiagnosticMessageId,
470 DiagnosticBuilderMethod::Note,
477 pub fn diag_span_suggestion_once<'a, 'b>(
479 diag_builder: &'b mut DiagnosticBuilder<'a>,
480 msg_id: DiagnosticMessageId,
487 DiagnosticBuilderMethod::SpanSuggestion(suggestion),
494 pub fn source_map<'a>(&'a self) -> &'a source_map::SourceMap {
495 self.parse_sess.source_map()
497 pub fn verbose(&self) -> bool {
498 self.opts.debugging_opts.verbose
500 pub fn time_passes(&self) -> bool {
501 self.opts.debugging_opts.time_passes
503 pub fn profile_queries(&self) -> bool {
504 self.opts.debugging_opts.profile_queries
505 || self.opts.debugging_opts.profile_queries_and_keys
507 pub fn profile_queries_and_keys(&self) -> bool {
508 self.opts.debugging_opts.profile_queries_and_keys
510 pub fn count_llvm_insns(&self) -> bool {
511 self.opts.debugging_opts.count_llvm_insns
513 pub fn time_llvm_passes(&self) -> bool {
514 self.opts.debugging_opts.time_llvm_passes
516 pub fn codegen_stats(&self) -> bool {
517 self.opts.debugging_opts.codegen_stats
519 pub fn meta_stats(&self) -> bool {
520 self.opts.debugging_opts.meta_stats
522 pub fn asm_comments(&self) -> bool {
523 self.opts.debugging_opts.asm_comments
525 pub fn verify_llvm_ir(&self) -> bool {
526 self.opts.debugging_opts.verify_llvm_ir
528 pub fn borrowck_stats(&self) -> bool {
529 self.opts.debugging_opts.borrowck_stats
531 pub fn print_llvm_passes(&self) -> bool {
532 self.opts.debugging_opts.print_llvm_passes
535 /// Get the features enabled for the current compilation session.
536 /// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents
537 /// dependency tracking. Use tcx.features() instead.
539 pub fn features_untracked(&self) -> &feature_gate::Features {
543 pub fn init_features(&self, features: feature_gate::Features) {
544 self.features.set(features);
547 /// Calculates the flavor of LTO to use for this compilation.
548 pub fn lto(&self) -> config::Lto {
549 // If our target has codegen requirements ignore the command line
550 if self.target.target.options.requires_lto {
551 return config::Lto::Fat;
554 // If the user specified something, return that. If they only said `-C
555 // lto` and we've for whatever reason forced off ThinLTO via the CLI,
556 // then ensure we can't use a ThinLTO.
557 match self.opts.cg.lto {
558 config::LtoCli::Unspecified => {
559 // The compiler was invoked without the `-Clto` flag. Fall
560 // through to the default handling
562 config::LtoCli::No => {
563 // The user explicitly opted out of any kind of LTO
564 return config::Lto::No;
566 config::LtoCli::Yes |
567 config::LtoCli::Fat |
568 config::LtoCli::NoParam => {
569 // All of these mean fat LTO
570 return config::Lto::Fat;
572 config::LtoCli::Thin => {
573 return if self.opts.cli_forced_thinlto_off {
581 // Ok at this point the target doesn't require anything and the user
582 // hasn't asked for anything. Our next decision is whether or not
583 // we enable "auto" ThinLTO where we use multiple codegen units and
584 // then do ThinLTO over those codegen units. The logic below will
585 // either return `No` or `ThinLocal`.
587 // If processing command line options determined that we're incompatible
588 // with ThinLTO (e.g. `-C lto --emit llvm-ir`) then return that option.
589 if self.opts.cli_forced_thinlto_off {
590 return config::Lto::No;
593 // If `-Z thinlto` specified process that, but note that this is mostly
594 // a deprecated option now that `-C lto=thin` exists.
595 if let Some(enabled) = self.opts.debugging_opts.thinlto {
597 return config::Lto::ThinLocal;
599 return config::Lto::No;
603 // If there's only one codegen unit and LTO isn't enabled then there's
604 // no need for ThinLTO so just return false.
605 if self.codegen_units() == 1 {
606 return config::Lto::No;
609 // Now we're in "defaults" territory. By default we enable ThinLTO for
610 // optimized compiles (anything greater than O0).
611 match self.opts.optimize {
612 config::OptLevel::No => config::Lto::No,
613 _ => config::Lto::ThinLocal,
617 /// Returns the panic strategy for this compile session. If the user explicitly selected one
618 /// using '-C panic', use that, otherwise use the panic strategy defined by the target.
619 pub fn panic_strategy(&self) -> PanicStrategy {
623 .unwrap_or(self.target.target.options.panic_strategy)
625 pub fn fewer_names(&self) -> bool {
626 let more_names = self.opts
628 .contains_key(&OutputType::LlvmAssembly)
629 || self.opts.output_types.contains_key(&OutputType::Bitcode);
630 self.opts.debugging_opts.fewer_names || !more_names
633 pub fn no_landing_pads(&self) -> bool {
634 self.opts.debugging_opts.no_landing_pads || self.panic_strategy() == PanicStrategy::Abort
636 pub fn unstable_options(&self) -> bool {
637 self.opts.debugging_opts.unstable_options
639 pub fn overflow_checks(&self) -> bool {
643 .or(self.opts.debugging_opts.force_overflow_checks)
644 .unwrap_or(self.opts.debug_assertions)
647 pub fn crt_static(&self) -> bool {
648 // If the target does not opt in to crt-static support, use its default.
649 if self.target.target.options.crt_static_respected {
650 self.crt_static_feature()
652 self.target.target.options.crt_static_default
656 pub fn crt_static_feature(&self) -> bool {
657 let requested_features = self.opts.cg.target_feature.split(',');
658 let found_negative = requested_features.clone().any(|r| r == "-crt-static");
659 let found_positive = requested_features.clone().any(|r| r == "+crt-static");
661 // If the target we're compiling for requests a static crt by default,
662 // then see if the `-crt-static` feature was passed to disable that.
663 // Otherwise if we don't have a static crt by default then see if the
664 // `+crt-static` feature was passed.
665 if self.target.target.options.crt_static_default {
672 pub fn must_not_eliminate_frame_pointers(&self) -> bool {
673 if let Some(x) = self.opts.cg.force_frame_pointers {
676 !self.target.target.options.eliminate_frame_pointer
680 /// Returns the symbol name for the registrar function,
681 /// given the crate Svh and the function DefIndex.
682 pub fn generate_plugin_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
684 "__rustc_plugin_registrar_{}__",
685 disambiguator.to_fingerprint().to_hex()
689 pub fn generate_derive_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
691 "__rustc_derive_registrar_{}__",
692 disambiguator.to_fingerprint().to_hex()
696 pub fn sysroot<'a>(&'a self) -> &'a Path {
697 match self.opts.maybe_sysroot {
698 Some(ref sysroot) => sysroot,
699 None => self.default_sysroot
701 .expect("missing sysroot and default_sysroot in Session"),
704 pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch {
705 filesearch::FileSearch::new(
707 self.opts.target_triple.triple(),
708 &self.opts.search_paths,
712 pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch {
713 filesearch::FileSearch::new(
715 config::host_triple(),
716 &self.opts.search_paths,
721 pub fn set_incr_session_load_dep_graph(&self, load: bool) {
722 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
724 match *incr_comp_session {
725 IncrCompSession::Active {
726 ref mut load_dep_graph,
729 *load_dep_graph = load;
735 pub fn incr_session_load_dep_graph(&self) -> bool {
736 let incr_comp_session = self.incr_comp_session.borrow();
737 match *incr_comp_session {
738 IncrCompSession::Active { load_dep_graph, .. } => load_dep_graph,
743 pub fn init_incr_comp_session(
745 session_dir: PathBuf,
746 lock_file: flock::Lock,
747 load_dep_graph: bool,
749 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
751 if let IncrCompSession::NotInitialized = *incr_comp_session {
754 "Trying to initialize IncrCompSession `{:?}`",
759 *incr_comp_session = IncrCompSession::Active {
760 session_directory: session_dir,
766 pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) {
767 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
769 if let IncrCompSession::Active { .. } = *incr_comp_session {
772 "Trying to finalize IncrCompSession `{:?}`",
777 // Note: This will also drop the lock file, thus unlocking the directory
778 *incr_comp_session = IncrCompSession::Finalized {
779 session_directory: new_directory_path,
783 pub fn mark_incr_comp_session_as_invalid(&self) {
784 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
786 let session_directory = match *incr_comp_session {
787 IncrCompSession::Active {
788 ref session_directory,
790 } => session_directory.clone(),
791 IncrCompSession::InvalidBecauseOfErrors { .. } => return,
793 "Trying to invalidate IncrCompSession `{:?}`",
798 // Note: This will also drop the lock file, thus unlocking the directory
799 *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors { session_directory };
802 pub fn incr_comp_session_dir(&self) -> cell::Ref<PathBuf> {
803 let incr_comp_session = self.incr_comp_session.borrow();
806 |incr_comp_session| match *incr_comp_session {
807 IncrCompSession::NotInitialized => bug!(
808 "Trying to get session directory from IncrCompSession `{:?}`",
811 IncrCompSession::Active {
812 ref session_directory,
815 | IncrCompSession::Finalized {
816 ref session_directory,
818 | IncrCompSession::InvalidBecauseOfErrors {
819 ref session_directory,
820 } => session_directory,
825 pub fn incr_comp_session_dir_opt(&self) -> Option<cell::Ref<PathBuf>> {
826 if self.opts.incremental.is_some() {
827 Some(self.incr_comp_session_dir())
833 pub fn profiler<F: FnOnce(&mut SelfProfiler) -> ()>(&self, f: F) {
834 let mut profiler = self.self_profiling.borrow_mut();
838 pub fn print_profiler_results(&self) {
839 let mut profiler = self.self_profiling.borrow_mut();
840 profiler.print_results(&self.opts);
843 pub fn save_json_results(&self) {
844 let profiler = self.self_profiling.borrow();
845 profiler.save_results(&self.opts);
848 pub fn print_perf_stats(&self) {
850 "Total time spent computing symbol hashes: {}",
851 duration_to_secs_str(*self.perf_stats.symbol_hash_time.lock())
854 "Total time spent decoding DefPath tables: {}",
855 duration_to_secs_str(*self.perf_stats.decode_def_path_tables_time.lock())
857 println!("Total queries canonicalized: {}",
858 self.perf_stats.queries_canonicalized.load(Ordering::Relaxed));
859 println!("normalize_ty_after_erasing_regions: {}",
860 self.perf_stats.normalize_ty_after_erasing_regions.load(Ordering::Relaxed));
861 println!("normalize_projection_ty: {}",
862 self.perf_stats.normalize_projection_ty.load(Ordering::Relaxed));
865 /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
866 /// This expends fuel if applicable, and records fuel if applicable.
867 pub fn consider_optimizing<T: Fn() -> String>(&self, crate_name: &str, msg: T) -> bool {
869 match self.optimization_fuel_crate {
870 Some(ref c) if c == crate_name => {
871 assert!(self.query_threads() == 1);
872 let fuel = self.optimization_fuel_limit.get();
874 if fuel == 0 && !self.out_of_fuel.get() {
875 println!("optimization-fuel-exhausted: {}", msg());
876 self.out_of_fuel.set(true);
878 self.optimization_fuel_limit.set(fuel - 1);
883 match self.print_fuel_crate {
884 Some(ref c) if c == crate_name => {
885 assert!(self.query_threads() == 1);
886 self.print_fuel.set(self.print_fuel.get() + 1);
893 /// Returns the number of query threads that should be used for this
895 pub fn query_threads_from_opts(opts: &config::Options) -> usize {
896 opts.debugging_opts.query_threads.unwrap_or(1)
899 /// Returns the number of query threads that should be used for this
901 pub fn query_threads(&self) -> usize {
902 Self::query_threads_from_opts(&self.opts)
905 /// Returns the number of codegen units that should be used for this
907 pub fn codegen_units(&self) -> usize {
908 if let Some(n) = self.opts.cli_forced_codegen_units {
911 if let Some(n) = self.target.target.options.default_codegen_units {
915 // Why is 16 codegen units the default all the time?
917 // The main reason for enabling multiple codegen units by default is to
918 // leverage the ability for the codegen backend to do codegen and
919 // optimization in parallel. This allows us, especially for large crates, to
920 // make good use of all available resources on the machine once we've
921 // hit that stage of compilation. Large crates especially then often
922 // take a long time in codegen/optimization and this helps us amortize that
925 // Note that a high number here doesn't mean that we'll be spawning a
926 // large number of threads in parallel. The backend of rustc contains
927 // global rate limiting through the `jobserver` crate so we'll never
928 // overload the system with too much work, but rather we'll only be
929 // optimizing when we're otherwise cooperating with other instances of
932 // Rather a high number here means that we should be able to keep a lot
933 // of idle cpus busy. By ensuring that no codegen unit takes *too* long
934 // to build we'll be guaranteed that all cpus will finish pretty closely
935 // to one another and we should make relatively optimal use of system
938 // Note that the main cost of codegen units is that it prevents LLVM
939 // from inlining across codegen units. Users in general don't have a lot
940 // of control over how codegen units are split up so it's our job in the
941 // compiler to ensure that undue performance isn't lost when using
942 // codegen units (aka we can't require everyone to slap `#[inline]` on
945 // If we're compiling at `-O0` then the number doesn't really matter too
946 // much because performance doesn't matter and inlining is ok to lose.
947 // In debug mode we just want to try to guarantee that no cpu is stuck
948 // doing work that could otherwise be farmed to others.
950 // In release mode, however (O1 and above) performance does indeed
951 // matter! To recover the loss in performance due to inlining we'll be
952 // enabling ThinLTO by default (the function for which is just below).
953 // This will ensure that we recover any inlining wins we otherwise lost
954 // through codegen unit partitioning.
958 // Ok that's a lot of words but the basic tl;dr; is that we want a high
959 // number here -- but not too high. Additionally we're "safe" to have it
960 // always at the same number at all optimization levels.
962 // As a result 16 was chosen here! Mostly because it was a power of 2
963 // and most benchmarks agreed it was roughly a local optimum. Not very
968 pub fn teach(&self, code: &DiagnosticId) -> bool {
969 self.opts.debugging_opts.teach && self.diagnostic().must_teach(code)
972 /// Are we allowed to use features from the Rust 2018 edition?
973 pub fn rust_2018(&self) -> bool {
974 self.opts.edition >= Edition::Edition2018
977 pub fn edition(&self) -> Edition {
982 pub fn build_session(
983 sopts: config::Options,
984 local_crate_source_file: Option<PathBuf>,
985 registry: errors::registry::Registry,
987 let file_path_mapping = sopts.file_path_mapping();
989 build_session_with_source_map(
991 local_crate_source_file,
993 Lrc::new(source_map::SourceMap::new(file_path_mapping)),
998 pub fn build_session_with_source_map(
999 sopts: config::Options,
1000 local_crate_source_file: Option<PathBuf>,
1001 registry: errors::registry::Registry,
1002 source_map: Lrc<source_map::SourceMap>,
1003 emitter_dest: Option<Box<dyn Write + Send>>,
1005 // FIXME: This is not general enough to make the warning lint completely override
1006 // normal diagnostic warnings, since the warning lint can also be denied and changed
1007 // later via the source code.
1008 let warnings_allow = sopts
1011 .filter(|&&(ref key, _)| *key == "warnings")
1012 .map(|&(_, ref level)| *level == lint::Allow)
1015 let cap_lints_allow = sopts.lint_cap.map_or(false, |cap| cap == lint::Allow);
1017 let can_emit_warnings = !(warnings_allow || cap_lints_allow);
1019 let treat_err_as_bug = sopts.debugging_opts.treat_err_as_bug;
1020 let dont_buffer_diagnostics = sopts.debugging_opts.dont_buffer_diagnostics;
1021 let report_delayed_bugs = sopts.debugging_opts.report_delayed_bugs;
1023 let external_macro_backtrace = sopts.debugging_opts.external_macro_backtrace;
1025 let emitter: Box<dyn Emitter + sync::Send> =
1026 match (sopts.error_format, emitter_dest) {
1027 (config::ErrorOutputType::HumanReadable(color_config), None) => Box::new(
1028 EmitterWriter::stderr(
1030 Some(source_map.clone()),
1032 sopts.debugging_opts.teach,
1033 ).ui_testing(sopts.debugging_opts.ui_testing),
1035 (config::ErrorOutputType::HumanReadable(_), Some(dst)) => Box::new(
1036 EmitterWriter::new(dst, Some(source_map.clone()), false, false)
1037 .ui_testing(sopts.debugging_opts.ui_testing),
1039 (config::ErrorOutputType::Json(pretty), None) => Box::new(
1040 JsonEmitter::stderr(
1044 ).ui_testing(sopts.debugging_opts.ui_testing),
1046 (config::ErrorOutputType::Json(pretty), Some(dst)) => Box::new(
1052 ).ui_testing(sopts.debugging_opts.ui_testing),
1054 (config::ErrorOutputType::Short(color_config), None) => Box::new(
1055 EmitterWriter::stderr(color_config, Some(source_map.clone()), true, false),
1057 (config::ErrorOutputType::Short(_), Some(dst)) => {
1058 Box::new(EmitterWriter::new(dst, Some(source_map.clone()), true, false))
1062 let diagnostic_handler = errors::Handler::with_emitter_and_flags(
1064 errors::HandlerFlags {
1067 report_delayed_bugs,
1068 dont_buffer_diagnostics,
1069 external_macro_backtrace,
1070 ..Default::default()
1074 build_session_(sopts, local_crate_source_file, diagnostic_handler, source_map)
1077 pub fn build_session_(
1078 sopts: config::Options,
1079 local_crate_source_file: Option<PathBuf>,
1080 span_diagnostic: errors::Handler,
1081 source_map: Lrc<source_map::SourceMap>,
1083 let host_triple = TargetTriple::from_triple(config::host_triple());
1084 let host = match Target::search(&host_triple) {
1088 .fatal(&format!("Error loading host specification: {}", e))
1092 let target_cfg = config::build_target_config(&sopts, &span_diagnostic);
1094 let p_s = parse::ParseSess::with_span_handler(span_diagnostic, source_map);
1095 let default_sysroot = match sopts.maybe_sysroot {
1097 None => Some(filesearch::get_or_default_sysroot()),
1100 let file_path_mapping = sopts.file_path_mapping();
1102 let local_crate_source_file =
1103 local_crate_source_file.map(|path| file_path_mapping.map_prefix(path).0);
1105 let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone());
1106 let optimization_fuel_limit =
1107 LockCell::new(sopts.debugging_opts.fuel.as_ref().map(|i| i.1).unwrap_or(0));
1108 let print_fuel_crate = sopts.debugging_opts.print_fuel.clone();
1109 let print_fuel = LockCell::new(0);
1111 let working_dir = match env::current_dir() {
1113 Err(e) => p_s.span_diagnostic
1114 .fatal(&format!("Current directory is invalid: {}", e))
1117 let working_dir = file_path_mapping.map_prefix(working_dir);
1119 let sess = Session {
1124 // For a library crate, this is always none
1125 entry_fn: Once::new(),
1126 plugin_registrar_fn: Once::new(),
1127 derive_registrar_fn: Once::new(),
1129 local_crate_source_file,
1131 lint_store: RwLock::new(lint::LintStore::new()),
1132 buffered_lints: Lock::new(Some(lint::LintBuffer::new())),
1133 one_time_diagnostics: Lock::new(FxHashSet()),
1134 plugin_llvm_passes: OneThread::new(RefCell::new(Vec::new())),
1135 plugin_attributes: OneThread::new(RefCell::new(Vec::new())),
1136 crate_types: Once::new(),
1137 dependency_formats: Once::new(),
1138 crate_disambiguator: Once::new(),
1139 features: Once::new(),
1140 recursion_limit: Once::new(),
1141 type_length_limit: Once::new(),
1142 const_eval_stack_frame_limit: 100,
1143 next_node_id: OneThread::new(Cell::new(NodeId::new(1))),
1144 injected_allocator: Once::new(),
1145 allocator_kind: Once::new(),
1146 injected_panic_runtime: Once::new(),
1147 imported_macro_spans: OneThread::new(RefCell::new(FxHashMap::default())),
1148 incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)),
1149 self_profiling: Lock::new(SelfProfiler::new()),
1150 profile_channel: Lock::new(None),
1151 perf_stats: PerfStats {
1152 symbol_hash_time: Lock::new(Duration::from_secs(0)),
1153 decode_def_path_tables_time: Lock::new(Duration::from_secs(0)),
1154 queries_canonicalized: AtomicUsize::new(0),
1155 normalize_ty_after_erasing_regions: AtomicUsize::new(0),
1156 normalize_projection_ty: AtomicUsize::new(0),
1158 code_stats: Lock::new(CodeStats::new()),
1159 optimization_fuel_crate,
1160 optimization_fuel_limit,
1163 out_of_fuel: LockCell::new(false),
1164 // Note that this is unsafe because it may misinterpret file descriptors
1165 // on Unix as jobserver file descriptors. We hopefully execute this near
1166 // the beginning of the process though to ensure we don't get false
1167 // positives, or in other words we try to execute this before we open
1168 // any file descriptors ourselves.
1170 // Pick a "reasonable maximum" if we don't otherwise have
1171 // a jobserver in our environment, capping out at 32 so we
1172 // don't take everything down by hogging the process run queue.
1173 // The fixed number is used to have deterministic compilation
1176 // Also note that we stick this in a global because there could be
1177 // multiple `Session` instances in this process, and the jobserver is
1180 static mut GLOBAL_JOBSERVER: *mut Client = 0 as *mut _;
1181 static INIT: std::sync::Once = std::sync::ONCE_INIT;
1183 let client = Client::from_env().unwrap_or_else(|| {
1184 Client::new(32).expect("failed to create jobserver")
1186 GLOBAL_JOBSERVER = Box::into_raw(Box::new(client));
1188 (*GLOBAL_JOBSERVER).clone()
1190 has_global_allocator: Once::new(),
1191 has_panic_handler: Once::new(),
1192 driver_lint_caps: FxHashMap(),
1195 validate_commandline_args_with_session_available(&sess);
1200 // If it is useful to have a Session available already for validating a
1201 // commandline argument, you can do so here.
1202 fn validate_commandline_args_with_session_available(sess: &Session) {
1204 if sess.opts.incremental.is_some() {
1208 sess.err("can't perform LTO when compiling incrementally");
1217 // Since we don't know if code in an rlib will be linked to statically or
1218 // dynamically downstream, rustc generates `__imp_` symbols that help the
1219 // MSVC linker deal with this lack of knowledge (#27438). Unfortunately,
1220 // these manually generated symbols confuse LLD when it tries to merge
1221 // bitcode during ThinLTO. Therefore we disallow dynamic linking on MSVC
1222 // when compiling for LLD ThinLTO. This way we can validly just not generate
1223 // the `dllimport` attributes and `__imp_` symbols in that case.
1224 if sess.opts.debugging_opts.cross_lang_lto.enabled() &&
1225 sess.opts.cg.prefer_dynamic &&
1226 sess.target.target.options.is_like_msvc {
1227 sess.err("Linker plugin based LTO is not supported together with \
1228 `-C prefer-dynamic` when targeting MSVC");
1232 /// Hash value constructed out of all the `-C metadata` arguments passed to the
1233 /// compiler. Together with the crate-name forms a unique global identifier for
1235 #[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy, RustcEncodable, RustcDecodable)]
1236 pub struct CrateDisambiguator(Fingerprint);
1238 impl CrateDisambiguator {
1239 pub fn to_fingerprint(self) -> Fingerprint {
1244 impl fmt::Display for CrateDisambiguator {
1245 fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
1246 let (a, b) = self.0.as_value();
1247 let as_u128 = a as u128 | ((b as u128) << 64);
1248 f.write_str(&base_n::encode(as_u128, base_n::CASE_INSENSITIVE))
1252 impl From<Fingerprint> for CrateDisambiguator {
1253 fn from(fingerprint: Fingerprint) -> CrateDisambiguator {
1254 CrateDisambiguator(fingerprint)
1258 impl_stable_hash_via_hash!(CrateDisambiguator);
1260 /// Holds data on the current incremental compilation session, if there is one.
1262 pub enum IncrCompSession {
1263 /// This is the state the session will be in until the incr. comp. dir is
1266 /// This is the state during which the session directory is private and can
1269 session_directory: PathBuf,
1270 lock_file: flock::Lock,
1271 load_dep_graph: bool,
1273 /// This is the state after the session directory has been finalized. In this
1274 /// state, the contents of the directory must not be modified any more.
1275 Finalized { session_directory: PathBuf },
1276 /// This is an error state that is reached when some compilation error has
1277 /// occurred. It indicates that the contents of the session directory must
1278 /// not be used, since they might be invalid.
1279 InvalidBecauseOfErrors { session_directory: PathBuf },
1282 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
1283 let emitter: Box<dyn Emitter + sync::Send> = match output {
1284 config::ErrorOutputType::HumanReadable(color_config) => {
1285 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1287 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1288 config::ErrorOutputType::Short(color_config) => {
1289 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1292 let handler = errors::Handler::with_emitter(true, false, emitter);
1293 handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal);
1294 errors::FatalError.raise();
1297 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
1298 let emitter: Box<dyn Emitter + sync::Send> = match output {
1299 config::ErrorOutputType::HumanReadable(color_config) => {
1300 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1302 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1303 config::ErrorOutputType::Short(color_config) => {
1304 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1307 let handler = errors::Handler::with_emitter(true, false, emitter);
1308 handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
1311 #[derive(Copy, Clone, Debug)]
1312 pub enum CompileIncomplete {
1314 Errored(ErrorReported),
1316 impl From<ErrorReported> for CompileIncomplete {
1317 fn from(err: ErrorReported) -> CompileIncomplete {
1318 CompileIncomplete::Errored(err)
1321 pub type CompileResult = Result<(), CompileIncomplete>;
1323 pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
1327 Err(CompileIncomplete::Errored(ErrorReported))