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 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::symbol::Symbol;
39 use syntax::parse::{self, ParseSess};
40 use syntax_pos::{MultiSpan, Span};
41 use util::profiling::SelfProfiler;
43 use rustc_target::spec::{PanicStrategy, RelroLevel, Target, TargetTriple};
44 use rustc_data_structures::flock;
45 use jobserver::Client;
48 use std::cell::{self, Cell, RefCell};
52 use std::path::{Path, PathBuf};
53 use std::time::Duration;
55 use std::sync::atomic::{AtomicUsize, Ordering};
62 /// Represents the data associated with a compilation
63 /// session for a single crate.
65 pub target: config::Config,
67 pub opts: config::Options,
68 pub parse_sess: ParseSess,
69 /// For a library crate, this is always none
70 pub entry_fn: Once<Option<(NodeId, Span, config::EntryFnType)>>,
71 pub plugin_registrar_fn: Once<Option<ast::NodeId>>,
72 pub derive_registrar_fn: Once<Option<ast::NodeId>>,
73 pub default_sysroot: Option<PathBuf>,
74 /// The name of the root source file of the crate, in the local file system.
75 /// `None` means that there is no source file.
76 pub local_crate_source_file: Option<PathBuf>,
77 /// The directory the compiler has been executed in plus a flag indicating
78 /// if the value stored here has been affected by path remapping.
79 pub working_dir: (PathBuf, bool),
81 // FIXME: lint_store and buffered_lints are not thread-safe,
82 // but are only used in a single thread
83 pub lint_store: RwLock<lint::LintStore>,
84 pub buffered_lints: Lock<Option<lint::LintBuffer>>,
86 /// Set of (DiagnosticId, Option<Span>, message) tuples tracking
87 /// (sub)diagnostics that have been set once, but should not be set again,
88 /// in order to avoid redundantly verbose output (Issue #24690, #44953).
89 pub one_time_diagnostics: Lock<FxHashSet<(DiagnosticMessageId, Option<Span>, String)>>,
90 pub plugin_llvm_passes: OneThread<RefCell<Vec<String>>>,
91 pub plugin_attributes: OneThread<RefCell<Vec<(String, AttributeType)>>>,
92 pub crate_types: Once<Vec<config::CrateType>>,
93 pub dependency_formats: Once<dependency_format::Dependencies>,
94 /// The crate_disambiguator is constructed out of all the `-C metadata`
95 /// arguments passed to the compiler. Its value together with the crate-name
96 /// forms a unique global identifier for the crate. It is used to allow
97 /// multiple crates with the same name to coexist. See the
98 /// rustc_codegen_llvm::back::symbol_names module for more information.
99 pub crate_disambiguator: Once<CrateDisambiguator>,
101 features: Once<feature_gate::Features>,
103 /// The maximum recursion limit for potentially infinitely recursive
104 /// operations such as auto-dereference and monomorphization.
105 pub recursion_limit: Once<usize>,
107 /// The maximum length of types during monomorphization.
108 pub type_length_limit: Once<usize>,
110 /// The maximum number of stackframes allowed in const eval
111 pub const_eval_stack_frame_limit: usize,
113 /// The metadata::creader module may inject an allocator/panic_runtime
114 /// dependency if it didn't already find one, and this tracks what was
116 pub injected_allocator: Once<Option<CrateNum>>,
117 pub allocator_kind: Once<Option<AllocatorKind>>,
118 pub injected_panic_runtime: Once<Option<CrateNum>>,
120 /// Map from imported macro spans (which consist of
121 /// the localized span for the macro body) to the
122 /// macro name and definition span in the source crate.
123 pub imported_macro_spans: OneThread<RefCell<FxHashMap<Span, (String, Span)>>>,
125 incr_comp_session: OneThread<RefCell<IncrCompSession>>,
126 /// Used for incremental compilation tests. Will only be populated if
127 /// `-Zquery-dep-graph` is specified.
128 pub cgu_reuse_tracker: CguReuseTracker,
130 /// Used by -Z profile-queries in util::common
131 pub profile_channel: Lock<Option<mpsc::Sender<ProfileQueriesMsg>>>,
133 /// Used by -Z self-profile
134 pub self_profiling: Lock<SelfProfiler>,
136 /// Some measurements that are being gathered during compilation.
137 pub perf_stats: PerfStats,
139 /// Data about code being compiled, gathered during compilation.
140 pub code_stats: Lock<CodeStats>,
142 next_node_id: OneThread<Cell<ast::NodeId>>,
144 /// If -zfuel=crate=n is specified, Some(crate).
145 optimization_fuel_crate: Option<String>,
146 /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0.
147 optimization_fuel_limit: LockCell<u64>,
148 /// We're rejecting all further optimizations.
149 out_of_fuel: LockCell<bool>,
151 // The next two are public because the driver needs to read them.
152 /// If -zprint-fuel=crate, Some(crate).
153 pub print_fuel_crate: Option<String>,
154 /// Always set to zero and incremented so that we can print fuel expended by a crate.
155 pub print_fuel: LockCell<u64>,
157 /// Loaded up early on in the initialization of this `Session` to avoid
158 /// false positives about a job server in our environment.
159 pub jobserver: Client,
161 /// Metadata about the allocators for the current crate being compiled
162 pub has_global_allocator: Once<bool>,
164 /// Metadata about the panic handlers for the current crate being compiled
165 pub has_panic_handler: Once<bool>,
167 /// Cap lint level specified by a driver specifically.
168 pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
170 /// All the crate names specified with `--extern`, and the builtin ones.
171 /// Starting with the Rust 2018 edition, absolute paths resolve in this set.
172 pub extern_prelude: FxHashSet<Symbol>,
175 pub struct PerfStats {
176 /// The accumulated time spent on computing symbol hashes
177 pub symbol_hash_time: Lock<Duration>,
178 /// The accumulated time spent decoding def path tables from metadata
179 pub decode_def_path_tables_time: Lock<Duration>,
180 /// Total number of values canonicalized queries constructed.
181 pub queries_canonicalized: AtomicUsize,
182 /// Number of times this query is invoked.
183 pub normalize_ty_after_erasing_regions: AtomicUsize,
184 /// Number of times this query is invoked.
185 pub normalize_projection_ty: AtomicUsize,
188 /// Enum to support dispatch of one-time diagnostics (in Session.diag_once)
189 enum DiagnosticBuilderMethod {
192 SpanSuggestion(String), // suggestion
193 // add more variants as needed to support one-time diagnostics
196 /// Diagnostic message ID—used by `Session.one_time_diagnostics` to avoid
197 /// emitting the same message more than once
198 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
199 pub enum DiagnosticMessageId {
200 ErrorId(u16), // EXXXX error code as integer
201 LintId(lint::LintId),
202 StabilityId(u32), // issue number
205 impl From<&'static lint::Lint> for DiagnosticMessageId {
206 fn from(lint: &'static lint::Lint) -> Self {
207 DiagnosticMessageId::LintId(lint::LintId::of(lint))
212 pub fn local_crate_disambiguator(&self) -> CrateDisambiguator {
213 *self.crate_disambiguator.get()
216 pub fn struct_span_warn<'a, S: Into<MultiSpan>>(
220 ) -> DiagnosticBuilder<'a> {
221 self.diagnostic().struct_span_warn(sp, msg)
223 pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(
228 ) -> DiagnosticBuilder<'a> {
229 self.diagnostic().struct_span_warn_with_code(sp, msg, code)
231 pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
232 self.diagnostic().struct_warn(msg)
234 pub fn struct_span_err<'a, S: Into<MultiSpan>>(
238 ) -> DiagnosticBuilder<'a> {
239 self.diagnostic().struct_span_err(sp, msg)
241 pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(
246 ) -> DiagnosticBuilder<'a> {
247 self.diagnostic().struct_span_err_with_code(sp, msg, code)
249 // FIXME: This method should be removed (every error should have an associated error code).
250 pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
251 self.diagnostic().struct_err(msg)
253 pub fn struct_err_with_code<'a>(
257 ) -> DiagnosticBuilder<'a> {
258 self.diagnostic().struct_err_with_code(msg, code)
260 pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(
264 ) -> DiagnosticBuilder<'a> {
265 self.diagnostic().struct_span_fatal(sp, msg)
267 pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(
272 ) -> DiagnosticBuilder<'a> {
273 self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
275 pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
276 self.diagnostic().struct_fatal(msg)
279 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
280 self.diagnostic().span_fatal(sp, msg).raise()
282 pub fn span_fatal_with_code<S: Into<MultiSpan>>(
289 .span_fatal_with_code(sp, msg, code)
292 pub fn fatal(&self, msg: &str) -> ! {
293 self.diagnostic().fatal(msg).raise()
295 pub fn span_err_or_warn<S: Into<MultiSpan>>(&self, is_warning: bool, sp: S, msg: &str) {
297 self.span_warn(sp, msg);
299 self.span_err(sp, msg);
302 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
303 self.diagnostic().span_err(sp, msg)
305 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
306 self.diagnostic().span_err_with_code(sp, &msg, code)
308 pub fn err(&self, msg: &str) {
309 self.diagnostic().err(msg)
311 pub fn err_count(&self) -> usize {
312 self.diagnostic().err_count()
314 pub fn has_errors(&self) -> bool {
315 self.diagnostic().has_errors()
317 pub fn abort_if_errors(&self) {
318 self.diagnostic().abort_if_errors();
320 pub fn compile_status(&self) -> Result<(), CompileIncomplete> {
321 compile_result_from_err_count(self.err_count())
323 pub fn track_errors<F, T>(&self, f: F) -> Result<T, ErrorReported>
327 let old_count = self.err_count();
329 let errors = self.err_count() - old_count;
336 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
337 self.diagnostic().span_warn(sp, msg)
339 pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
340 self.diagnostic().span_warn_with_code(sp, msg, code)
342 pub fn warn(&self, msg: &str) {
343 self.diagnostic().warn(msg)
345 pub fn opt_span_warn<S: Into<MultiSpan>>(&self, opt_sp: Option<S>, msg: &str) {
347 Some(sp) => self.span_warn(sp, msg),
348 None => self.warn(msg),
351 /// Delay a span_bug() call until abort_if_errors()
352 pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
353 self.diagnostic().delay_span_bug(sp, msg)
355 pub fn note_without_error(&self, msg: &str) {
356 self.diagnostic().note_without_error(msg)
358 pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
359 self.diagnostic().span_note_without_error(sp, msg)
361 pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
362 self.diagnostic().span_unimpl(sp, msg)
364 pub fn unimpl(&self, msg: &str) -> ! {
365 self.diagnostic().unimpl(msg)
368 pub fn buffer_lint<S: Into<MultiSpan>>(
370 lint: &'static lint::Lint,
375 match *self.buffered_lints.borrow_mut() {
376 Some(ref mut buffer) => {
377 buffer.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal)
379 None => bug!("can't buffer lints after HIR lowering"),
383 pub fn buffer_lint_with_diagnostic<S: Into<MultiSpan>>(
385 lint: &'static lint::Lint,
389 diagnostic: BuiltinLintDiagnostics,
391 match *self.buffered_lints.borrow_mut() {
392 Some(ref mut buffer) => buffer.add_lint(lint, id, sp.into(), msg, diagnostic),
393 None => bug!("can't buffer lints after HIR lowering"),
397 pub fn reserve_node_ids(&self, count: usize) -> ast::NodeId {
398 let id = self.next_node_id.get();
400 match id.as_usize().checked_add(count) {
402 self.next_node_id.set(ast::NodeId::new(next));
404 None => bug!("Input too large, ran out of node ids!"),
409 pub fn next_node_id(&self) -> NodeId {
410 self.reserve_node_ids(1)
412 pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler {
413 &self.parse_sess.span_diagnostic
416 /// Analogous to calling methods on the given `DiagnosticBuilder`, but
417 /// deduplicates on lint ID, span (if any), and message for this `Session`
418 fn diag_once<'a, 'b>(
420 diag_builder: &'b mut DiagnosticBuilder<'a>,
421 method: DiagnosticBuilderMethod,
422 msg_id: DiagnosticMessageId,
424 span_maybe: Option<Span>,
426 let id_span_message = (msg_id, span_maybe, message.to_owned());
427 let fresh = self.one_time_diagnostics
429 .insert(id_span_message);
432 DiagnosticBuilderMethod::Note => {
433 diag_builder.note(message);
435 DiagnosticBuilderMethod::SpanNote => {
436 let span = span_maybe.expect("span_note needs a span");
437 diag_builder.span_note(span, message);
439 DiagnosticBuilderMethod::SpanSuggestion(suggestion) => {
440 let span = span_maybe.expect("span_suggestion_* needs a span");
441 diag_builder.span_suggestion_with_applicability(
445 Applicability::Unspecified,
452 pub fn diag_span_note_once<'a, 'b>(
454 diag_builder: &'b mut DiagnosticBuilder<'a>,
455 msg_id: DiagnosticMessageId,
461 DiagnosticBuilderMethod::SpanNote,
468 pub fn diag_note_once<'a, 'b>(
470 diag_builder: &'b mut DiagnosticBuilder<'a>,
471 msg_id: DiagnosticMessageId,
476 DiagnosticBuilderMethod::Note,
483 pub fn diag_span_suggestion_once<'a, 'b>(
485 diag_builder: &'b mut DiagnosticBuilder<'a>,
486 msg_id: DiagnosticMessageId,
493 DiagnosticBuilderMethod::SpanSuggestion(suggestion),
500 pub fn source_map<'a>(&'a self) -> &'a source_map::SourceMap {
501 self.parse_sess.source_map()
503 pub fn verbose(&self) -> bool {
504 self.opts.debugging_opts.verbose
506 pub fn time_passes(&self) -> bool {
507 self.opts.debugging_opts.time_passes
509 pub fn profile_queries(&self) -> bool {
510 self.opts.debugging_opts.profile_queries
511 || self.opts.debugging_opts.profile_queries_and_keys
513 pub fn profile_queries_and_keys(&self) -> bool {
514 self.opts.debugging_opts.profile_queries_and_keys
516 pub fn count_llvm_insns(&self) -> bool {
517 self.opts.debugging_opts.count_llvm_insns
519 pub fn time_llvm_passes(&self) -> bool {
520 self.opts.debugging_opts.time_llvm_passes
522 pub fn codegen_stats(&self) -> bool {
523 self.opts.debugging_opts.codegen_stats
525 pub fn meta_stats(&self) -> bool {
526 self.opts.debugging_opts.meta_stats
528 pub fn asm_comments(&self) -> bool {
529 self.opts.debugging_opts.asm_comments
531 pub fn verify_llvm_ir(&self) -> bool {
532 self.opts.debugging_opts.verify_llvm_ir
534 pub fn borrowck_stats(&self) -> bool {
535 self.opts.debugging_opts.borrowck_stats
537 pub fn print_llvm_passes(&self) -> bool {
538 self.opts.debugging_opts.print_llvm_passes
541 /// Get the features enabled for the current compilation session.
542 /// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents
543 /// dependency tracking. Use tcx.features() instead.
545 pub fn features_untracked(&self) -> &feature_gate::Features {
549 pub fn init_features(&self, features: feature_gate::Features) {
550 self.features.set(features);
553 /// Calculates the flavor of LTO to use for this compilation.
554 pub fn lto(&self) -> config::Lto {
555 // If our target has codegen requirements ignore the command line
556 if self.target.target.options.requires_lto {
557 return config::Lto::Fat;
560 // If the user specified something, return that. If they only said `-C
561 // lto` and we've for whatever reason forced off ThinLTO via the CLI,
562 // then ensure we can't use a ThinLTO.
563 match self.opts.cg.lto {
564 config::LtoCli::Unspecified => {
565 // The compiler was invoked without the `-Clto` flag. Fall
566 // through to the default handling
568 config::LtoCli::No => {
569 // The user explicitly opted out of any kind of LTO
570 return config::Lto::No;
572 config::LtoCli::Yes |
573 config::LtoCli::Fat |
574 config::LtoCli::NoParam => {
575 // All of these mean fat LTO
576 return config::Lto::Fat;
578 config::LtoCli::Thin => {
579 return if self.opts.cli_forced_thinlto_off {
587 // Ok at this point the target doesn't require anything and the user
588 // hasn't asked for anything. Our next decision is whether or not
589 // we enable "auto" ThinLTO where we use multiple codegen units and
590 // then do ThinLTO over those codegen units. The logic below will
591 // either return `No` or `ThinLocal`.
593 // If processing command line options determined that we're incompatible
594 // with ThinLTO (e.g. `-C lto --emit llvm-ir`) then return that option.
595 if self.opts.cli_forced_thinlto_off {
596 return config::Lto::No;
599 // If `-Z thinlto` specified process that, but note that this is mostly
600 // a deprecated option now that `-C lto=thin` exists.
601 if let Some(enabled) = self.opts.debugging_opts.thinlto {
603 return config::Lto::ThinLocal;
605 return config::Lto::No;
609 // If there's only one codegen unit and LTO isn't enabled then there's
610 // no need for ThinLTO so just return false.
611 if self.codegen_units() == 1 {
612 return config::Lto::No;
615 // Now we're in "defaults" territory. By default we enable ThinLTO for
616 // optimized compiles (anything greater than O0).
617 match self.opts.optimize {
618 config::OptLevel::No => config::Lto::No,
619 _ => config::Lto::ThinLocal,
623 /// Returns the panic strategy for this compile session. If the user explicitly selected one
624 /// using '-C panic', use that, otherwise use the panic strategy defined by the target.
625 pub fn panic_strategy(&self) -> PanicStrategy {
629 .unwrap_or(self.target.target.options.panic_strategy)
631 pub fn fewer_names(&self) -> bool {
632 let more_names = self.opts
634 .contains_key(&OutputType::LlvmAssembly)
635 || self.opts.output_types.contains_key(&OutputType::Bitcode);
636 self.opts.debugging_opts.fewer_names || !more_names
639 pub fn no_landing_pads(&self) -> bool {
640 self.opts.debugging_opts.no_landing_pads || self.panic_strategy() == PanicStrategy::Abort
642 pub fn unstable_options(&self) -> bool {
643 self.opts.debugging_opts.unstable_options
645 pub fn overflow_checks(&self) -> bool {
649 .or(self.opts.debugging_opts.force_overflow_checks)
650 .unwrap_or(self.opts.debug_assertions)
653 pub fn crt_static(&self) -> bool {
654 // If the target does not opt in to crt-static support, use its default.
655 if self.target.target.options.crt_static_respected {
656 self.crt_static_feature()
658 self.target.target.options.crt_static_default
662 pub fn crt_static_feature(&self) -> bool {
663 let requested_features = self.opts.cg.target_feature.split(',');
664 let found_negative = requested_features.clone().any(|r| r == "-crt-static");
665 let found_positive = requested_features.clone().any(|r| r == "+crt-static");
667 // If the target we're compiling for requests a static crt by default,
668 // then see if the `-crt-static` feature was passed to disable that.
669 // Otherwise if we don't have a static crt by default then see if the
670 // `+crt-static` feature was passed.
671 if self.target.target.options.crt_static_default {
678 pub fn must_not_eliminate_frame_pointers(&self) -> bool {
679 if let Some(x) = self.opts.cg.force_frame_pointers {
682 !self.target.target.options.eliminate_frame_pointer
686 /// Returns the symbol name for the registrar function,
687 /// given the crate Svh and the function DefIndex.
688 pub fn generate_plugin_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
690 "__rustc_plugin_registrar_{}__",
691 disambiguator.to_fingerprint().to_hex()
695 pub fn generate_derive_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
697 "__rustc_derive_registrar_{}__",
698 disambiguator.to_fingerprint().to_hex()
702 pub fn sysroot<'a>(&'a self) -> &'a Path {
703 match self.opts.maybe_sysroot {
704 Some(ref sysroot) => sysroot,
705 None => self.default_sysroot
707 .expect("missing sysroot and default_sysroot in Session"),
710 pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
711 filesearch::FileSearch::new(
713 self.opts.target_triple.triple(),
714 &self.opts.search_paths,
718 pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
719 filesearch::FileSearch::new(
721 config::host_triple(),
722 &self.opts.search_paths,
727 pub fn set_incr_session_load_dep_graph(&self, load: bool) {
728 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
730 match *incr_comp_session {
731 IncrCompSession::Active {
732 ref mut load_dep_graph,
735 *load_dep_graph = load;
741 pub fn incr_session_load_dep_graph(&self) -> bool {
742 let incr_comp_session = self.incr_comp_session.borrow();
743 match *incr_comp_session {
744 IncrCompSession::Active { load_dep_graph, .. } => load_dep_graph,
749 pub fn init_incr_comp_session(
751 session_dir: PathBuf,
752 lock_file: flock::Lock,
753 load_dep_graph: bool,
755 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
757 if let IncrCompSession::NotInitialized = *incr_comp_session {
760 "Trying to initialize IncrCompSession `{:?}`",
765 *incr_comp_session = IncrCompSession::Active {
766 session_directory: session_dir,
772 pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) {
773 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
775 if let IncrCompSession::Active { .. } = *incr_comp_session {
778 "Trying to finalize IncrCompSession `{:?}`",
783 // Note: This will also drop the lock file, thus unlocking the directory
784 *incr_comp_session = IncrCompSession::Finalized {
785 session_directory: new_directory_path,
789 pub fn mark_incr_comp_session_as_invalid(&self) {
790 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
792 let session_directory = match *incr_comp_session {
793 IncrCompSession::Active {
794 ref session_directory,
796 } => session_directory.clone(),
797 IncrCompSession::InvalidBecauseOfErrors { .. } => return,
799 "Trying to invalidate IncrCompSession `{:?}`",
804 // Note: This will also drop the lock file, thus unlocking the directory
805 *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors { session_directory };
808 pub fn incr_comp_session_dir(&self) -> cell::Ref<'_, PathBuf> {
809 let incr_comp_session = self.incr_comp_session.borrow();
812 |incr_comp_session| match *incr_comp_session {
813 IncrCompSession::NotInitialized => bug!(
814 "Trying to get session directory from IncrCompSession `{:?}`",
817 IncrCompSession::Active {
818 ref session_directory,
821 | IncrCompSession::Finalized {
822 ref session_directory,
824 | IncrCompSession::InvalidBecauseOfErrors {
825 ref session_directory,
826 } => session_directory,
831 pub fn incr_comp_session_dir_opt(&self) -> Option<cell::Ref<'_, PathBuf>> {
832 if self.opts.incremental.is_some() {
833 Some(self.incr_comp_session_dir())
839 pub fn profiler<F: FnOnce(&mut SelfProfiler) -> ()>(&self, f: F) {
840 let mut profiler = self.self_profiling.borrow_mut();
844 pub fn print_profiler_results(&self) {
845 let mut profiler = self.self_profiling.borrow_mut();
846 profiler.print_results(&self.opts);
849 pub fn save_json_results(&self) {
850 let profiler = self.self_profiling.borrow();
851 profiler.save_results(&self.opts);
854 pub fn print_perf_stats(&self) {
856 "Total time spent computing symbol hashes: {}",
857 duration_to_secs_str(*self.perf_stats.symbol_hash_time.lock())
860 "Total time spent decoding DefPath tables: {}",
861 duration_to_secs_str(*self.perf_stats.decode_def_path_tables_time.lock())
863 println!("Total queries canonicalized: {}",
864 self.perf_stats.queries_canonicalized.load(Ordering::Relaxed));
865 println!("normalize_ty_after_erasing_regions: {}",
866 self.perf_stats.normalize_ty_after_erasing_regions.load(Ordering::Relaxed));
867 println!("normalize_projection_ty: {}",
868 self.perf_stats.normalize_projection_ty.load(Ordering::Relaxed));
871 /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
872 /// This expends fuel if applicable, and records fuel if applicable.
873 pub fn consider_optimizing<T: Fn() -> String>(&self, crate_name: &str, msg: T) -> bool {
875 match self.optimization_fuel_crate {
876 Some(ref c) if c == crate_name => {
877 assert!(self.query_threads() == 1);
878 let fuel = self.optimization_fuel_limit.get();
880 if fuel == 0 && !self.out_of_fuel.get() {
881 println!("optimization-fuel-exhausted: {}", msg());
882 self.out_of_fuel.set(true);
884 self.optimization_fuel_limit.set(fuel - 1);
889 match self.print_fuel_crate {
890 Some(ref c) if c == crate_name => {
891 assert!(self.query_threads() == 1);
892 self.print_fuel.set(self.print_fuel.get() + 1);
899 /// Returns the number of query threads that should be used for this
901 pub fn query_threads_from_opts(opts: &config::Options) -> usize {
902 opts.debugging_opts.query_threads.unwrap_or(1)
905 /// Returns the number of query threads that should be used for this
907 pub fn query_threads(&self) -> usize {
908 Self::query_threads_from_opts(&self.opts)
911 /// Returns the number of codegen units that should be used for this
913 pub fn codegen_units(&self) -> usize {
914 if let Some(n) = self.opts.cli_forced_codegen_units {
917 if let Some(n) = self.target.target.options.default_codegen_units {
921 // Why is 16 codegen units the default all the time?
923 // The main reason for enabling multiple codegen units by default is to
924 // leverage the ability for the codegen backend to do codegen and
925 // optimization in parallel. This allows us, especially for large crates, to
926 // make good use of all available resources on the machine once we've
927 // hit that stage of compilation. Large crates especially then often
928 // take a long time in codegen/optimization and this helps us amortize that
931 // Note that a high number here doesn't mean that we'll be spawning a
932 // large number of threads in parallel. The backend of rustc contains
933 // global rate limiting through the `jobserver` crate so we'll never
934 // overload the system with too much work, but rather we'll only be
935 // optimizing when we're otherwise cooperating with other instances of
938 // Rather a high number here means that we should be able to keep a lot
939 // of idle cpus busy. By ensuring that no codegen unit takes *too* long
940 // to build we'll be guaranteed that all cpus will finish pretty closely
941 // to one another and we should make relatively optimal use of system
944 // Note that the main cost of codegen units is that it prevents LLVM
945 // from inlining across codegen units. Users in general don't have a lot
946 // of control over how codegen units are split up so it's our job in the
947 // compiler to ensure that undue performance isn't lost when using
948 // codegen units (aka we can't require everyone to slap `#[inline]` on
951 // If we're compiling at `-O0` then the number doesn't really matter too
952 // much because performance doesn't matter and inlining is ok to lose.
953 // In debug mode we just want to try to guarantee that no cpu is stuck
954 // doing work that could otherwise be farmed to others.
956 // In release mode, however (O1 and above) performance does indeed
957 // matter! To recover the loss in performance due to inlining we'll be
958 // enabling ThinLTO by default (the function for which is just below).
959 // This will ensure that we recover any inlining wins we otherwise lost
960 // through codegen unit partitioning.
964 // Ok that's a lot of words but the basic tl;dr; is that we want a high
965 // number here -- but not too high. Additionally we're "safe" to have it
966 // always at the same number at all optimization levels.
968 // As a result 16 was chosen here! Mostly because it was a power of 2
969 // and most benchmarks agreed it was roughly a local optimum. Not very
974 pub fn teach(&self, code: &DiagnosticId) -> bool {
975 self.opts.debugging_opts.teach && self.diagnostic().must_teach(code)
978 /// Are we allowed to use features from the Rust 2018 edition?
979 pub fn rust_2018(&self) -> bool {
980 self.opts.edition >= Edition::Edition2018
983 pub fn edition(&self) -> Edition {
987 /// True if we cannot skip the PLT for shared library calls.
988 pub fn needs_plt(&self) -> bool {
989 // Check if the current target usually needs PLT to be enabled.
990 // The user can use the command line flag to override it.
991 let needs_plt = self.target.target.options.needs_plt;
993 let dbg_opts = &self.opts.debugging_opts;
995 let relro_level = dbg_opts.relro_level
996 .unwrap_or(self.target.target.options.relro_level);
998 // Only enable this optimization by default if full relro is also enabled.
999 // In this case, lazy binding was already unavailable, so nothing is lost.
1000 // This also ensures `-Wl,-z,now` is supported by the linker.
1001 let full_relro = RelroLevel::Full == relro_level;
1003 // If user didn't explicitly forced us to use / skip the PLT,
1004 // then try to skip it where possible.
1005 dbg_opts.plt.unwrap_or(needs_plt || !full_relro)
1009 pub fn build_session(
1010 sopts: config::Options,
1011 local_crate_source_file: Option<PathBuf>,
1012 registry: errors::registry::Registry,
1014 let file_path_mapping = sopts.file_path_mapping();
1016 build_session_with_source_map(
1018 local_crate_source_file,
1020 Lrc::new(source_map::SourceMap::new(file_path_mapping)),
1025 pub fn build_session_with_source_map(
1026 sopts: config::Options,
1027 local_crate_source_file: Option<PathBuf>,
1028 registry: errors::registry::Registry,
1029 source_map: Lrc<source_map::SourceMap>,
1030 emitter_dest: Option<Box<dyn Write + Send>>,
1032 // FIXME: This is not general enough to make the warning lint completely override
1033 // normal diagnostic warnings, since the warning lint can also be denied and changed
1034 // later via the source code.
1035 let warnings_allow = sopts
1038 .filter(|&&(ref key, _)| *key == "warnings")
1039 .map(|&(_, ref level)| *level == lint::Allow)
1042 let cap_lints_allow = sopts.lint_cap.map_or(false, |cap| cap == lint::Allow);
1044 let can_emit_warnings = !(warnings_allow || cap_lints_allow);
1046 let treat_err_as_bug = sopts.debugging_opts.treat_err_as_bug;
1047 let dont_buffer_diagnostics = sopts.debugging_opts.dont_buffer_diagnostics;
1048 let report_delayed_bugs = sopts.debugging_opts.report_delayed_bugs;
1050 let external_macro_backtrace = sopts.debugging_opts.external_macro_backtrace;
1052 let emitter: Box<dyn Emitter + sync::Send> =
1053 match (sopts.error_format, emitter_dest) {
1054 (config::ErrorOutputType::HumanReadable(color_config), None) => Box::new(
1055 EmitterWriter::stderr(
1057 Some(source_map.clone()),
1059 sopts.debugging_opts.teach,
1060 ).ui_testing(sopts.debugging_opts.ui_testing),
1062 (config::ErrorOutputType::HumanReadable(_), Some(dst)) => Box::new(
1063 EmitterWriter::new(dst, Some(source_map.clone()), false, false)
1064 .ui_testing(sopts.debugging_opts.ui_testing),
1066 (config::ErrorOutputType::Json(pretty), None) => Box::new(
1067 JsonEmitter::stderr(
1071 ).ui_testing(sopts.debugging_opts.ui_testing),
1073 (config::ErrorOutputType::Json(pretty), Some(dst)) => Box::new(
1079 ).ui_testing(sopts.debugging_opts.ui_testing),
1081 (config::ErrorOutputType::Short(color_config), None) => Box::new(
1082 EmitterWriter::stderr(color_config, Some(source_map.clone()), true, false),
1084 (config::ErrorOutputType::Short(_), Some(dst)) => {
1085 Box::new(EmitterWriter::new(dst, Some(source_map.clone()), true, false))
1089 let diagnostic_handler = errors::Handler::with_emitter_and_flags(
1091 errors::HandlerFlags {
1094 report_delayed_bugs,
1095 dont_buffer_diagnostics,
1096 external_macro_backtrace,
1097 ..Default::default()
1101 build_session_(sopts, local_crate_source_file, diagnostic_handler, source_map)
1104 pub fn build_session_(
1105 sopts: config::Options,
1106 local_crate_source_file: Option<PathBuf>,
1107 span_diagnostic: errors::Handler,
1108 source_map: Lrc<source_map::SourceMap>,
1110 let host_triple = TargetTriple::from_triple(config::host_triple());
1111 let host = match Target::search(&host_triple) {
1115 .fatal(&format!("Error loading host specification: {}", e))
1119 let target_cfg = config::build_target_config(&sopts, &span_diagnostic);
1121 let p_s = parse::ParseSess::with_span_handler(span_diagnostic, source_map);
1122 let default_sysroot = match sopts.maybe_sysroot {
1124 None => Some(filesearch::get_or_default_sysroot()),
1127 let file_path_mapping = sopts.file_path_mapping();
1129 let local_crate_source_file =
1130 local_crate_source_file.map(|path| file_path_mapping.map_prefix(path).0);
1132 let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone());
1133 let optimization_fuel_limit =
1134 LockCell::new(sopts.debugging_opts.fuel.as_ref().map(|i| i.1).unwrap_or(0));
1135 let print_fuel_crate = sopts.debugging_opts.print_fuel.clone();
1136 let print_fuel = LockCell::new(0);
1138 let working_dir = match env::current_dir() {
1140 Err(e) => p_s.span_diagnostic
1141 .fatal(&format!("Current directory is invalid: {}", e))
1144 let working_dir = file_path_mapping.map_prefix(working_dir);
1146 let cgu_reuse_tracker = if sopts.debugging_opts.query_dep_graph {
1147 CguReuseTracker::new()
1149 CguReuseTracker::new_disabled()
1153 let mut extern_prelude: FxHashSet<Symbol> =
1154 sopts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1156 // HACK(eddyb) this ignores the `no_{core,std}` attributes.
1157 // FIXME(eddyb) warn (somewhere) if core/std is used with `no_{core,std}`.
1158 // if !attr::contains_name(&krate.attrs, "no_core") {
1159 // if !attr::contains_name(&krate.attrs, "no_std") {
1160 extern_prelude.insert(Symbol::intern("core"));
1161 extern_prelude.insert(Symbol::intern("std"));
1162 extern_prelude.insert(Symbol::intern("meta"));
1164 let sess = Session {
1169 // For a library crate, this is always none
1170 entry_fn: Once::new(),
1171 plugin_registrar_fn: Once::new(),
1172 derive_registrar_fn: Once::new(),
1174 local_crate_source_file,
1176 lint_store: RwLock::new(lint::LintStore::new()),
1177 buffered_lints: Lock::new(Some(lint::LintBuffer::new())),
1178 one_time_diagnostics: Lock::new(FxHashSet()),
1179 plugin_llvm_passes: OneThread::new(RefCell::new(Vec::new())),
1180 plugin_attributes: OneThread::new(RefCell::new(Vec::new())),
1181 crate_types: Once::new(),
1182 dependency_formats: Once::new(),
1183 crate_disambiguator: Once::new(),
1184 features: Once::new(),
1185 recursion_limit: Once::new(),
1186 type_length_limit: Once::new(),
1187 const_eval_stack_frame_limit: 100,
1188 next_node_id: OneThread::new(Cell::new(NodeId::new(1))),
1189 injected_allocator: Once::new(),
1190 allocator_kind: Once::new(),
1191 injected_panic_runtime: Once::new(),
1192 imported_macro_spans: OneThread::new(RefCell::new(FxHashMap::default())),
1193 incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)),
1195 self_profiling: Lock::new(SelfProfiler::new()),
1196 profile_channel: Lock::new(None),
1197 perf_stats: PerfStats {
1198 symbol_hash_time: Lock::new(Duration::from_secs(0)),
1199 decode_def_path_tables_time: Lock::new(Duration::from_secs(0)),
1200 queries_canonicalized: AtomicUsize::new(0),
1201 normalize_ty_after_erasing_regions: AtomicUsize::new(0),
1202 normalize_projection_ty: AtomicUsize::new(0),
1204 code_stats: Lock::new(CodeStats::new()),
1205 optimization_fuel_crate,
1206 optimization_fuel_limit,
1209 out_of_fuel: LockCell::new(false),
1210 // Note that this is unsafe because it may misinterpret file descriptors
1211 // on Unix as jobserver file descriptors. We hopefully execute this near
1212 // the beginning of the process though to ensure we don't get false
1213 // positives, or in other words we try to execute this before we open
1214 // any file descriptors ourselves.
1216 // Pick a "reasonable maximum" if we don't otherwise have
1217 // a jobserver in our environment, capping out at 32 so we
1218 // don't take everything down by hogging the process run queue.
1219 // The fixed number is used to have deterministic compilation
1222 // Also note that we stick this in a global because there could be
1223 // multiple `Session` instances in this process, and the jobserver is
1226 static mut GLOBAL_JOBSERVER: *mut Client = 0 as *mut _;
1227 static INIT: std::sync::Once = std::sync::ONCE_INIT;
1229 let client = Client::from_env().unwrap_or_else(|| {
1230 Client::new(32).expect("failed to create jobserver")
1232 GLOBAL_JOBSERVER = Box::into_raw(Box::new(client));
1234 (*GLOBAL_JOBSERVER).clone()
1236 has_global_allocator: Once::new(),
1237 has_panic_handler: Once::new(),
1238 driver_lint_caps: FxHashMap(),
1242 validate_commandline_args_with_session_available(&sess);
1247 // If it is useful to have a Session available already for validating a
1248 // commandline argument, you can do so here.
1249 fn validate_commandline_args_with_session_available(sess: &Session) {
1251 if sess.opts.incremental.is_some() {
1255 sess.err("can't perform LTO when compiling incrementally");
1264 // Since we don't know if code in an rlib will be linked to statically or
1265 // dynamically downstream, rustc generates `__imp_` symbols that help the
1266 // MSVC linker deal with this lack of knowledge (#27438). Unfortunately,
1267 // these manually generated symbols confuse LLD when it tries to merge
1268 // bitcode during ThinLTO. Therefore we disallow dynamic linking on MSVC
1269 // when compiling for LLD ThinLTO. This way we can validly just not generate
1270 // the `dllimport` attributes and `__imp_` symbols in that case.
1271 if sess.opts.debugging_opts.cross_lang_lto.enabled() &&
1272 sess.opts.cg.prefer_dynamic &&
1273 sess.target.target.options.is_like_msvc {
1274 sess.err("Linker plugin based LTO is not supported together with \
1275 `-C prefer-dynamic` when targeting MSVC");
1279 /// Hash value constructed out of all the `-C metadata` arguments passed to the
1280 /// compiler. Together with the crate-name forms a unique global identifier for
1282 #[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy, RustcEncodable, RustcDecodable)]
1283 pub struct CrateDisambiguator(Fingerprint);
1285 impl CrateDisambiguator {
1286 pub fn to_fingerprint(self) -> Fingerprint {
1291 impl fmt::Display for CrateDisambiguator {
1292 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
1293 let (a, b) = self.0.as_value();
1294 let as_u128 = a as u128 | ((b as u128) << 64);
1295 f.write_str(&base_n::encode(as_u128, base_n::CASE_INSENSITIVE))
1299 impl From<Fingerprint> for CrateDisambiguator {
1300 fn from(fingerprint: Fingerprint) -> CrateDisambiguator {
1301 CrateDisambiguator(fingerprint)
1305 impl_stable_hash_via_hash!(CrateDisambiguator);
1307 /// Holds data on the current incremental compilation session, if there is one.
1309 pub enum IncrCompSession {
1310 /// This is the state the session will be in until the incr. comp. dir is
1313 /// This is the state during which the session directory is private and can
1316 session_directory: PathBuf,
1317 lock_file: flock::Lock,
1318 load_dep_graph: bool,
1320 /// This is the state after the session directory has been finalized. In this
1321 /// state, the contents of the directory must not be modified any more.
1322 Finalized { session_directory: PathBuf },
1323 /// This is an error state that is reached when some compilation error has
1324 /// occurred. It indicates that the contents of the session directory must
1325 /// not be used, since they might be invalid.
1326 InvalidBecauseOfErrors { session_directory: PathBuf },
1329 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
1330 let emitter: Box<dyn Emitter + sync::Send> = match output {
1331 config::ErrorOutputType::HumanReadable(color_config) => {
1332 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1334 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1335 config::ErrorOutputType::Short(color_config) => {
1336 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1339 let handler = errors::Handler::with_emitter(true, false, emitter);
1340 handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal);
1341 errors::FatalError.raise();
1344 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
1345 let emitter: Box<dyn Emitter + sync::Send> = match output {
1346 config::ErrorOutputType::HumanReadable(color_config) => {
1347 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1349 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1350 config::ErrorOutputType::Short(color_config) => {
1351 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1354 let handler = errors::Handler::with_emitter(true, false, emitter);
1355 handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
1358 #[derive(Copy, Clone, Debug)]
1359 pub enum CompileIncomplete {
1361 Errored(ErrorReported),
1363 impl From<ErrorReported> for CompileIncomplete {
1364 fn from(err: ErrorReported) -> CompileIncomplete {
1365 CompileIncomplete::Errored(err)
1368 pub type CompileResult = Result<(), CompileIncomplete>;
1370 pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
1374 Err(CompileIncomplete::Errored(ErrorReported))