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;
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>>,
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>,
171 /// All the crate names specified with `--extern`, and the builtin ones.
172 /// Starting with the Rust 2018 edition, absolute paths resolve in this set.
173 pub extern_prelude: FxHashSet<Symbol>,
176 pub struct PerfStats {
177 /// The accumulated time spent on computing symbol hashes
178 pub symbol_hash_time: Lock<Duration>,
179 /// The accumulated time spent decoding def path tables from metadata
180 pub decode_def_path_tables_time: Lock<Duration>,
181 /// Total number of values canonicalized queries constructed.
182 pub queries_canonicalized: AtomicUsize,
183 /// Number of times this query is invoked.
184 pub normalize_ty_after_erasing_regions: AtomicUsize,
185 /// Number of times this query is invoked.
186 pub normalize_projection_ty: AtomicUsize,
189 /// Enum to support dispatch of one-time diagnostics (in Session.diag_once)
190 enum DiagnosticBuilderMethod {
193 SpanSuggestion(String), // suggestion
194 // add more variants as needed to support one-time diagnostics
197 /// Diagnostic message ID—used by `Session.one_time_diagnostics` to avoid
198 /// emitting the same message more than once
199 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
200 pub enum DiagnosticMessageId {
201 ErrorId(u16), // EXXXX error code as integer
202 LintId(lint::LintId),
203 StabilityId(u32), // issue number
206 impl From<&'static lint::Lint> for DiagnosticMessageId {
207 fn from(lint: &'static lint::Lint) -> Self {
208 DiagnosticMessageId::LintId(lint::LintId::of(lint))
213 pub fn local_crate_disambiguator(&self) -> CrateDisambiguator {
214 *self.crate_disambiguator.get()
217 pub fn struct_span_warn<'a, S: Into<MultiSpan>>(
221 ) -> DiagnosticBuilder<'a> {
222 self.diagnostic().struct_span_warn(sp, msg)
224 pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(
229 ) -> DiagnosticBuilder<'a> {
230 self.diagnostic().struct_span_warn_with_code(sp, msg, code)
232 pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
233 self.diagnostic().struct_warn(msg)
235 pub fn struct_span_err<'a, S: Into<MultiSpan>>(
239 ) -> DiagnosticBuilder<'a> {
240 self.diagnostic().struct_span_err(sp, msg)
242 pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(
247 ) -> DiagnosticBuilder<'a> {
248 self.diagnostic().struct_span_err_with_code(sp, msg, code)
250 // FIXME: This method should be removed (every error should have an associated error code).
251 pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
252 self.diagnostic().struct_err(msg)
254 pub fn struct_err_with_code<'a>(
258 ) -> DiagnosticBuilder<'a> {
259 self.diagnostic().struct_err_with_code(msg, code)
261 pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(
265 ) -> DiagnosticBuilder<'a> {
266 self.diagnostic().struct_span_fatal(sp, msg)
268 pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(
273 ) -> DiagnosticBuilder<'a> {
274 self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
276 pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
277 self.diagnostic().struct_fatal(msg)
280 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
281 self.diagnostic().span_fatal(sp, msg).raise()
283 pub fn span_fatal_with_code<S: Into<MultiSpan>>(
290 .span_fatal_with_code(sp, msg, code)
293 pub fn fatal(&self, msg: &str) -> ! {
294 self.diagnostic().fatal(msg).raise()
296 pub fn span_err_or_warn<S: Into<MultiSpan>>(&self, is_warning: bool, sp: S, msg: &str) {
298 self.span_warn(sp, msg);
300 self.span_err(sp, msg);
303 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
304 self.diagnostic().span_err(sp, msg)
306 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
307 self.diagnostic().span_err_with_code(sp, &msg, code)
309 pub fn err(&self, msg: &str) {
310 self.diagnostic().err(msg)
312 pub fn err_count(&self) -> usize {
313 self.diagnostic().err_count()
315 pub fn has_errors(&self) -> bool {
316 self.diagnostic().has_errors()
318 pub fn abort_if_errors(&self) {
319 self.diagnostic().abort_if_errors();
321 pub fn compile_status(&self) -> Result<(), CompileIncomplete> {
322 compile_result_from_err_count(self.err_count())
324 pub fn track_errors<F, T>(&self, f: F) -> Result<T, ErrorReported>
328 let old_count = self.err_count();
330 let errors = self.err_count() - old_count;
337 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
338 self.diagnostic().span_warn(sp, msg)
340 pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
341 self.diagnostic().span_warn_with_code(sp, msg, code)
343 pub fn warn(&self, msg: &str) {
344 self.diagnostic().warn(msg)
346 pub fn opt_span_warn<S: Into<MultiSpan>>(&self, opt_sp: Option<S>, msg: &str) {
348 Some(sp) => self.span_warn(sp, msg),
349 None => self.warn(msg),
352 /// Delay a span_bug() call until abort_if_errors()
353 pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
354 self.diagnostic().delay_span_bug(sp, msg)
356 pub fn note_without_error(&self, msg: &str) {
357 self.diagnostic().note_without_error(msg)
359 pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
360 self.diagnostic().span_note_without_error(sp, msg)
362 pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
363 self.diagnostic().span_unimpl(sp, msg)
365 pub fn unimpl(&self, msg: &str) -> ! {
366 self.diagnostic().unimpl(msg)
369 pub fn buffer_lint<S: Into<MultiSpan>>(
371 lint: &'static lint::Lint,
376 match *self.buffered_lints.borrow_mut() {
377 Some(ref mut buffer) => {
378 buffer.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal)
380 None => bug!("can't buffer lints after HIR lowering"),
384 pub fn buffer_lint_with_diagnostic<S: Into<MultiSpan>>(
386 lint: &'static lint::Lint,
390 diagnostic: BuiltinLintDiagnostics,
392 match *self.buffered_lints.borrow_mut() {
393 Some(ref mut buffer) => buffer.add_lint(lint, id, sp.into(), msg, diagnostic),
394 None => bug!("can't buffer lints after HIR lowering"),
398 pub fn reserve_node_ids(&self, count: usize) -> ast::NodeId {
399 let id = self.next_node_id.get();
401 match id.as_usize().checked_add(count) {
403 self.next_node_id.set(ast::NodeId::new(next));
405 None => bug!("Input too large, ran out of node ids!"),
410 pub fn next_node_id(&self) -> NodeId {
411 self.reserve_node_ids(1)
413 pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler {
414 &self.parse_sess.span_diagnostic
417 /// Analogous to calling methods on the given `DiagnosticBuilder`, but
418 /// deduplicates on lint ID, span (if any), and message for this `Session`
419 fn diag_once<'a, 'b>(
421 diag_builder: &'b mut DiagnosticBuilder<'a>,
422 method: DiagnosticBuilderMethod,
423 msg_id: DiagnosticMessageId,
425 span_maybe: Option<Span>,
427 let id_span_message = (msg_id, span_maybe, message.to_owned());
428 let fresh = self.one_time_diagnostics
430 .insert(id_span_message);
433 DiagnosticBuilderMethod::Note => {
434 diag_builder.note(message);
436 DiagnosticBuilderMethod::SpanNote => {
437 let span = span_maybe.expect("span_note needs a span");
438 diag_builder.span_note(span, message);
440 DiagnosticBuilderMethod::SpanSuggestion(suggestion) => {
441 let span = span_maybe.expect("span_suggestion_* needs a span");
442 diag_builder.span_suggestion_with_applicability(
446 Applicability::Unspecified,
453 pub fn diag_span_note_once<'a, 'b>(
455 diag_builder: &'b mut DiagnosticBuilder<'a>,
456 msg_id: DiagnosticMessageId,
462 DiagnosticBuilderMethod::SpanNote,
469 pub fn diag_note_once<'a, 'b>(
471 diag_builder: &'b mut DiagnosticBuilder<'a>,
472 msg_id: DiagnosticMessageId,
477 DiagnosticBuilderMethod::Note,
484 pub fn diag_span_suggestion_once<'a, 'b>(
486 diag_builder: &'b mut DiagnosticBuilder<'a>,
487 msg_id: DiagnosticMessageId,
494 DiagnosticBuilderMethod::SpanSuggestion(suggestion),
501 pub fn source_map<'a>(&'a self) -> &'a source_map::SourceMap {
502 self.parse_sess.source_map()
504 pub fn verbose(&self) -> bool {
505 self.opts.debugging_opts.verbose
507 pub fn time_passes(&self) -> bool {
508 self.opts.debugging_opts.time_passes
510 pub fn profile_queries(&self) -> bool {
511 self.opts.debugging_opts.profile_queries
512 || self.opts.debugging_opts.profile_queries_and_keys
514 pub fn profile_queries_and_keys(&self) -> bool {
515 self.opts.debugging_opts.profile_queries_and_keys
517 pub fn count_llvm_insns(&self) -> bool {
518 self.opts.debugging_opts.count_llvm_insns
520 pub fn time_llvm_passes(&self) -> bool {
521 self.opts.debugging_opts.time_llvm_passes
523 pub fn codegen_stats(&self) -> bool {
524 self.opts.debugging_opts.codegen_stats
526 pub fn meta_stats(&self) -> bool {
527 self.opts.debugging_opts.meta_stats
529 pub fn asm_comments(&self) -> bool {
530 self.opts.debugging_opts.asm_comments
532 pub fn verify_llvm_ir(&self) -> bool {
533 self.opts.debugging_opts.verify_llvm_ir
535 pub fn borrowck_stats(&self) -> bool {
536 self.opts.debugging_opts.borrowck_stats
538 pub fn print_llvm_passes(&self) -> bool {
539 self.opts.debugging_opts.print_llvm_passes
542 /// Get the features enabled for the current compilation session.
543 /// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents
544 /// dependency tracking. Use tcx.features() instead.
546 pub fn features_untracked(&self) -> &feature_gate::Features {
550 pub fn init_features(&self, features: feature_gate::Features) {
551 self.features.set(features);
554 /// Calculates the flavor of LTO to use for this compilation.
555 pub fn lto(&self) -> config::Lto {
556 // If our target has codegen requirements ignore the command line
557 if self.target.target.options.requires_lto {
558 return config::Lto::Fat;
561 // If the user specified something, return that. If they only said `-C
562 // lto` and we've for whatever reason forced off ThinLTO via the CLI,
563 // then ensure we can't use a ThinLTO.
564 match self.opts.cg.lto {
565 config::LtoCli::Unspecified => {
566 // The compiler was invoked without the `-Clto` flag. Fall
567 // through to the default handling
569 config::LtoCli::No => {
570 // The user explicitly opted out of any kind of LTO
571 return config::Lto::No;
573 config::LtoCli::Yes |
574 config::LtoCli::Fat |
575 config::LtoCli::NoParam => {
576 // All of these mean fat LTO
577 return config::Lto::Fat;
579 config::LtoCli::Thin => {
580 return if self.opts.cli_forced_thinlto_off {
588 // Ok at this point the target doesn't require anything and the user
589 // hasn't asked for anything. Our next decision is whether or not
590 // we enable "auto" ThinLTO where we use multiple codegen units and
591 // then do ThinLTO over those codegen units. The logic below will
592 // either return `No` or `ThinLocal`.
594 // If processing command line options determined that we're incompatible
595 // with ThinLTO (e.g. `-C lto --emit llvm-ir`) then return that option.
596 if self.opts.cli_forced_thinlto_off {
597 return config::Lto::No;
600 // If `-Z thinlto` specified process that, but note that this is mostly
601 // a deprecated option now that `-C lto=thin` exists.
602 if let Some(enabled) = self.opts.debugging_opts.thinlto {
604 return config::Lto::ThinLocal;
606 return config::Lto::No;
610 // If there's only one codegen unit and LTO isn't enabled then there's
611 // no need for ThinLTO so just return false.
612 if self.codegen_units() == 1 {
613 return config::Lto::No;
616 // Now we're in "defaults" territory. By default we enable ThinLTO for
617 // optimized compiles (anything greater than O0).
618 match self.opts.optimize {
619 config::OptLevel::No => config::Lto::No,
620 _ => config::Lto::ThinLocal,
624 /// Returns the panic strategy for this compile session. If the user explicitly selected one
625 /// using '-C panic', use that, otherwise use the panic strategy defined by the target.
626 pub fn panic_strategy(&self) -> PanicStrategy {
630 .unwrap_or(self.target.target.options.panic_strategy)
632 pub fn fewer_names(&self) -> bool {
633 let more_names = self.opts
635 .contains_key(&OutputType::LlvmAssembly)
636 || self.opts.output_types.contains_key(&OutputType::Bitcode);
637 self.opts.debugging_opts.fewer_names || !more_names
640 pub fn no_landing_pads(&self) -> bool {
641 self.opts.debugging_opts.no_landing_pads || self.panic_strategy() == PanicStrategy::Abort
643 pub fn unstable_options(&self) -> bool {
644 self.opts.debugging_opts.unstable_options
646 pub fn overflow_checks(&self) -> bool {
650 .or(self.opts.debugging_opts.force_overflow_checks)
651 .unwrap_or(self.opts.debug_assertions)
654 pub fn crt_static(&self) -> bool {
655 // If the target does not opt in to crt-static support, use its default.
656 if self.target.target.options.crt_static_respected {
657 self.crt_static_feature()
659 self.target.target.options.crt_static_default
663 pub fn crt_static_feature(&self) -> bool {
664 let requested_features = self.opts.cg.target_feature.split(',');
665 let found_negative = requested_features.clone().any(|r| r == "-crt-static");
666 let found_positive = requested_features.clone().any(|r| r == "+crt-static");
668 // If the target we're compiling for requests a static crt by default,
669 // then see if the `-crt-static` feature was passed to disable that.
670 // Otherwise if we don't have a static crt by default then see if the
671 // `+crt-static` feature was passed.
672 if self.target.target.options.crt_static_default {
679 pub fn must_not_eliminate_frame_pointers(&self) -> bool {
680 if let Some(x) = self.opts.cg.force_frame_pointers {
683 !self.target.target.options.eliminate_frame_pointer
687 /// Returns the symbol name for the registrar function,
688 /// given the crate Svh and the function DefIndex.
689 pub fn generate_plugin_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
691 "__rustc_plugin_registrar_{}__",
692 disambiguator.to_fingerprint().to_hex()
696 pub fn generate_derive_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
698 "__rustc_derive_registrar_{}__",
699 disambiguator.to_fingerprint().to_hex()
703 pub fn sysroot<'a>(&'a self) -> &'a Path {
704 match self.opts.maybe_sysroot {
705 Some(ref sysroot) => sysroot,
706 None => self.default_sysroot
708 .expect("missing sysroot and default_sysroot in Session"),
711 pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
712 filesearch::FileSearch::new(
714 self.opts.target_triple.triple(),
715 &self.opts.search_paths,
719 pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
720 filesearch::FileSearch::new(
722 config::host_triple(),
723 &self.opts.search_paths,
728 pub fn set_incr_session_load_dep_graph(&self, load: bool) {
729 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
731 match *incr_comp_session {
732 IncrCompSession::Active {
733 ref mut load_dep_graph,
736 *load_dep_graph = load;
742 pub fn incr_session_load_dep_graph(&self) -> bool {
743 let incr_comp_session = self.incr_comp_session.borrow();
744 match *incr_comp_session {
745 IncrCompSession::Active { load_dep_graph, .. } => load_dep_graph,
750 pub fn init_incr_comp_session(
752 session_dir: PathBuf,
753 lock_file: flock::Lock,
754 load_dep_graph: bool,
756 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
758 if let IncrCompSession::NotInitialized = *incr_comp_session {
761 "Trying to initialize IncrCompSession `{:?}`",
766 *incr_comp_session = IncrCompSession::Active {
767 session_directory: session_dir,
773 pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) {
774 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
776 if let IncrCompSession::Active { .. } = *incr_comp_session {
779 "Trying to finalize IncrCompSession `{:?}`",
784 // Note: This will also drop the lock file, thus unlocking the directory
785 *incr_comp_session = IncrCompSession::Finalized {
786 session_directory: new_directory_path,
790 pub fn mark_incr_comp_session_as_invalid(&self) {
791 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
793 let session_directory = match *incr_comp_session {
794 IncrCompSession::Active {
795 ref session_directory,
797 } => session_directory.clone(),
798 IncrCompSession::InvalidBecauseOfErrors { .. } => return,
800 "Trying to invalidate IncrCompSession `{:?}`",
805 // Note: This will also drop the lock file, thus unlocking the directory
806 *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors { session_directory };
809 pub fn incr_comp_session_dir(&self) -> cell::Ref<'_, PathBuf> {
810 let incr_comp_session = self.incr_comp_session.borrow();
813 |incr_comp_session| match *incr_comp_session {
814 IncrCompSession::NotInitialized => bug!(
815 "Trying to get session directory from IncrCompSession `{:?}`",
818 IncrCompSession::Active {
819 ref session_directory,
822 | IncrCompSession::Finalized {
823 ref session_directory,
825 | IncrCompSession::InvalidBecauseOfErrors {
826 ref session_directory,
827 } => session_directory,
832 pub fn incr_comp_session_dir_opt(&self) -> Option<cell::Ref<'_, PathBuf>> {
833 if self.opts.incremental.is_some() {
834 Some(self.incr_comp_session_dir())
840 pub fn profiler<F: FnOnce(&mut SelfProfiler) -> ()>(&self, f: F) {
841 let mut profiler = self.self_profiling.borrow_mut();
845 pub fn print_profiler_results(&self) {
846 let mut profiler = self.self_profiling.borrow_mut();
847 profiler.print_results(&self.opts);
850 pub fn save_json_results(&self) {
851 let profiler = self.self_profiling.borrow();
852 profiler.save_results(&self.opts);
855 pub fn print_perf_stats(&self) {
857 "Total time spent computing symbol hashes: {}",
858 duration_to_secs_str(*self.perf_stats.symbol_hash_time.lock())
861 "Total time spent decoding DefPath tables: {}",
862 duration_to_secs_str(*self.perf_stats.decode_def_path_tables_time.lock())
864 println!("Total queries canonicalized: {}",
865 self.perf_stats.queries_canonicalized.load(Ordering::Relaxed));
866 println!("normalize_ty_after_erasing_regions: {}",
867 self.perf_stats.normalize_ty_after_erasing_regions.load(Ordering::Relaxed));
868 println!("normalize_projection_ty: {}",
869 self.perf_stats.normalize_projection_ty.load(Ordering::Relaxed));
872 /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
873 /// This expends fuel if applicable, and records fuel if applicable.
874 pub fn consider_optimizing<T: Fn() -> String>(&self, crate_name: &str, msg: T) -> bool {
876 match self.optimization_fuel_crate {
877 Some(ref c) if c == crate_name => {
878 assert!(self.query_threads() == 1);
879 let fuel = self.optimization_fuel_limit.get();
881 if fuel == 0 && !self.out_of_fuel.get() {
882 println!("optimization-fuel-exhausted: {}", msg());
883 self.out_of_fuel.set(true);
885 self.optimization_fuel_limit.set(fuel - 1);
890 match self.print_fuel_crate {
891 Some(ref c) if c == crate_name => {
892 assert!(self.query_threads() == 1);
893 self.print_fuel.set(self.print_fuel.get() + 1);
900 /// Returns the number of query threads that should be used for this
902 pub fn query_threads_from_opts(opts: &config::Options) -> usize {
903 opts.debugging_opts.query_threads.unwrap_or(1)
906 /// Returns the number of query threads that should be used for this
908 pub fn query_threads(&self) -> usize {
909 Self::query_threads_from_opts(&self.opts)
912 /// Returns the number of codegen units that should be used for this
914 pub fn codegen_units(&self) -> usize {
915 if let Some(n) = self.opts.cli_forced_codegen_units {
918 if let Some(n) = self.target.target.options.default_codegen_units {
922 // Why is 16 codegen units the default all the time?
924 // The main reason for enabling multiple codegen units by default is to
925 // leverage the ability for the codegen backend to do codegen and
926 // optimization in parallel. This allows us, especially for large crates, to
927 // make good use of all available resources on the machine once we've
928 // hit that stage of compilation. Large crates especially then often
929 // take a long time in codegen/optimization and this helps us amortize that
932 // Note that a high number here doesn't mean that we'll be spawning a
933 // large number of threads in parallel. The backend of rustc contains
934 // global rate limiting through the `jobserver` crate so we'll never
935 // overload the system with too much work, but rather we'll only be
936 // optimizing when we're otherwise cooperating with other instances of
939 // Rather a high number here means that we should be able to keep a lot
940 // of idle cpus busy. By ensuring that no codegen unit takes *too* long
941 // to build we'll be guaranteed that all cpus will finish pretty closely
942 // to one another and we should make relatively optimal use of system
945 // Note that the main cost of codegen units is that it prevents LLVM
946 // from inlining across codegen units. Users in general don't have a lot
947 // of control over how codegen units are split up so it's our job in the
948 // compiler to ensure that undue performance isn't lost when using
949 // codegen units (aka we can't require everyone to slap `#[inline]` on
952 // If we're compiling at `-O0` then the number doesn't really matter too
953 // much because performance doesn't matter and inlining is ok to lose.
954 // In debug mode we just want to try to guarantee that no cpu is stuck
955 // doing work that could otherwise be farmed to others.
957 // In release mode, however (O1 and above) performance does indeed
958 // matter! To recover the loss in performance due to inlining we'll be
959 // enabling ThinLTO by default (the function for which is just below).
960 // This will ensure that we recover any inlining wins we otherwise lost
961 // through codegen unit partitioning.
965 // Ok that's a lot of words but the basic tl;dr; is that we want a high
966 // number here -- but not too high. Additionally we're "safe" to have it
967 // always at the same number at all optimization levels.
969 // As a result 16 was chosen here! Mostly because it was a power of 2
970 // and most benchmarks agreed it was roughly a local optimum. Not very
975 pub fn teach(&self, code: &DiagnosticId) -> bool {
976 self.opts.debugging_opts.teach && self.diagnostic().must_teach(code)
979 /// Are we allowed to use features from the Rust 2018 edition?
980 pub fn rust_2018(&self) -> bool {
981 self.opts.edition >= Edition::Edition2018
984 pub fn edition(&self) -> Edition {
989 pub fn build_session(
990 sopts: config::Options,
991 local_crate_source_file: Option<PathBuf>,
992 registry: errors::registry::Registry,
994 let file_path_mapping = sopts.file_path_mapping();
996 build_session_with_source_map(
998 local_crate_source_file,
1000 Lrc::new(source_map::SourceMap::new(file_path_mapping)),
1005 pub fn build_session_with_source_map(
1006 sopts: config::Options,
1007 local_crate_source_file: Option<PathBuf>,
1008 registry: errors::registry::Registry,
1009 source_map: Lrc<source_map::SourceMap>,
1010 emitter_dest: Option<Box<dyn Write + Send>>,
1012 // FIXME: This is not general enough to make the warning lint completely override
1013 // normal diagnostic warnings, since the warning lint can also be denied and changed
1014 // later via the source code.
1015 let warnings_allow = sopts
1018 .filter(|&&(ref key, _)| *key == "warnings")
1019 .map(|&(_, ref level)| *level == lint::Allow)
1022 let cap_lints_allow = sopts.lint_cap.map_or(false, |cap| cap == lint::Allow);
1024 let can_emit_warnings = !(warnings_allow || cap_lints_allow);
1026 let treat_err_as_bug = sopts.debugging_opts.treat_err_as_bug;
1027 let dont_buffer_diagnostics = sopts.debugging_opts.dont_buffer_diagnostics;
1028 let report_delayed_bugs = sopts.debugging_opts.report_delayed_bugs;
1030 let external_macro_backtrace = sopts.debugging_opts.external_macro_backtrace;
1032 let emitter: Box<dyn Emitter + sync::Send> =
1033 match (sopts.error_format, emitter_dest) {
1034 (config::ErrorOutputType::HumanReadable(color_config), None) => Box::new(
1035 EmitterWriter::stderr(
1037 Some(source_map.clone()),
1039 sopts.debugging_opts.teach,
1040 ).ui_testing(sopts.debugging_opts.ui_testing),
1042 (config::ErrorOutputType::HumanReadable(_), Some(dst)) => Box::new(
1043 EmitterWriter::new(dst, Some(source_map.clone()), false, false)
1044 .ui_testing(sopts.debugging_opts.ui_testing),
1046 (config::ErrorOutputType::Json(pretty), None) => Box::new(
1047 JsonEmitter::stderr(
1051 ).ui_testing(sopts.debugging_opts.ui_testing),
1053 (config::ErrorOutputType::Json(pretty), Some(dst)) => Box::new(
1059 ).ui_testing(sopts.debugging_opts.ui_testing),
1061 (config::ErrorOutputType::Short(color_config), None) => Box::new(
1062 EmitterWriter::stderr(color_config, Some(source_map.clone()), true, false),
1064 (config::ErrorOutputType::Short(_), Some(dst)) => {
1065 Box::new(EmitterWriter::new(dst, Some(source_map.clone()), true, false))
1069 let diagnostic_handler = errors::Handler::with_emitter_and_flags(
1071 errors::HandlerFlags {
1074 report_delayed_bugs,
1075 dont_buffer_diagnostics,
1076 external_macro_backtrace,
1077 ..Default::default()
1081 build_session_(sopts, local_crate_source_file, diagnostic_handler, source_map)
1084 pub fn build_session_(
1085 sopts: config::Options,
1086 local_crate_source_file: Option<PathBuf>,
1087 span_diagnostic: errors::Handler,
1088 source_map: Lrc<source_map::SourceMap>,
1090 let host_triple = TargetTriple::from_triple(config::host_triple());
1091 let host = match Target::search(&host_triple) {
1095 .fatal(&format!("Error loading host specification: {}", e))
1099 let target_cfg = config::build_target_config(&sopts, &span_diagnostic);
1101 let p_s = parse::ParseSess::with_span_handler(span_diagnostic, source_map);
1102 let default_sysroot = match sopts.maybe_sysroot {
1104 None => Some(filesearch::get_or_default_sysroot()),
1107 let file_path_mapping = sopts.file_path_mapping();
1109 let local_crate_source_file =
1110 local_crate_source_file.map(|path| file_path_mapping.map_prefix(path).0);
1112 let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone());
1113 let optimization_fuel_limit =
1114 LockCell::new(sopts.debugging_opts.fuel.as_ref().map(|i| i.1).unwrap_or(0));
1115 let print_fuel_crate = sopts.debugging_opts.print_fuel.clone();
1116 let print_fuel = LockCell::new(0);
1118 let working_dir = match env::current_dir() {
1120 Err(e) => p_s.span_diagnostic
1121 .fatal(&format!("Current directory is invalid: {}", e))
1124 let working_dir = file_path_mapping.map_prefix(working_dir);
1126 let cgu_reuse_tracker = if sopts.debugging_opts.query_dep_graph {
1127 CguReuseTracker::new()
1129 CguReuseTracker::new_disabled()
1133 let mut extern_prelude: FxHashSet<Symbol> =
1134 sopts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1136 // HACK(eddyb) this ignores the `no_{core,std}` attributes.
1137 // FIXME(eddyb) warn (somewhere) if core/std is used with `no_{core,std}`.
1138 // if !attr::contains_name(&krate.attrs, "no_core") {
1139 // if !attr::contains_name(&krate.attrs, "no_std") {
1140 extern_prelude.insert(Symbol::intern("core"));
1141 extern_prelude.insert(Symbol::intern("std"));
1142 extern_prelude.insert(Symbol::intern("meta"));
1144 let sess = Session {
1149 // For a library crate, this is always none
1150 entry_fn: Once::new(),
1151 plugin_registrar_fn: Once::new(),
1152 derive_registrar_fn: Once::new(),
1154 local_crate_source_file,
1156 lint_store: RwLock::new(lint::LintStore::new()),
1157 buffered_lints: Lock::new(Some(lint::LintBuffer::new())),
1158 one_time_diagnostics: Lock::new(FxHashSet()),
1159 plugin_llvm_passes: OneThread::new(RefCell::new(Vec::new())),
1160 plugin_attributes: OneThread::new(RefCell::new(Vec::new())),
1161 crate_types: Once::new(),
1162 dependency_formats: Once::new(),
1163 crate_disambiguator: Once::new(),
1164 features: Once::new(),
1165 recursion_limit: Once::new(),
1166 type_length_limit: Once::new(),
1167 const_eval_stack_frame_limit: 100,
1168 next_node_id: OneThread::new(Cell::new(NodeId::new(1))),
1169 injected_allocator: Once::new(),
1170 allocator_kind: Once::new(),
1171 injected_panic_runtime: Once::new(),
1172 imported_macro_spans: OneThread::new(RefCell::new(FxHashMap::default())),
1173 incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)),
1175 self_profiling: Lock::new(SelfProfiler::new()),
1176 profile_channel: Lock::new(None),
1177 perf_stats: PerfStats {
1178 symbol_hash_time: Lock::new(Duration::from_secs(0)),
1179 decode_def_path_tables_time: Lock::new(Duration::from_secs(0)),
1180 queries_canonicalized: AtomicUsize::new(0),
1181 normalize_ty_after_erasing_regions: AtomicUsize::new(0),
1182 normalize_projection_ty: AtomicUsize::new(0),
1184 code_stats: Lock::new(CodeStats::new()),
1185 optimization_fuel_crate,
1186 optimization_fuel_limit,
1189 out_of_fuel: LockCell::new(false),
1190 // Note that this is unsafe because it may misinterpret file descriptors
1191 // on Unix as jobserver file descriptors. We hopefully execute this near
1192 // the beginning of the process though to ensure we don't get false
1193 // positives, or in other words we try to execute this before we open
1194 // any file descriptors ourselves.
1196 // Pick a "reasonable maximum" if we don't otherwise have
1197 // a jobserver in our environment, capping out at 32 so we
1198 // don't take everything down by hogging the process run queue.
1199 // The fixed number is used to have deterministic compilation
1202 // Also note that we stick this in a global because there could be
1203 // multiple `Session` instances in this process, and the jobserver is
1206 static mut GLOBAL_JOBSERVER: *mut Client = 0 as *mut _;
1207 static INIT: std::sync::Once = std::sync::ONCE_INIT;
1209 let client = Client::from_env().unwrap_or_else(|| {
1210 Client::new(32).expect("failed to create jobserver")
1212 GLOBAL_JOBSERVER = Box::into_raw(Box::new(client));
1214 (*GLOBAL_JOBSERVER).clone()
1216 has_global_allocator: Once::new(),
1217 has_panic_handler: Once::new(),
1218 driver_lint_caps: FxHashMap(),
1222 validate_commandline_args_with_session_available(&sess);
1227 // If it is useful to have a Session available already for validating a
1228 // commandline argument, you can do so here.
1229 fn validate_commandline_args_with_session_available(sess: &Session) {
1231 if sess.opts.incremental.is_some() {
1235 sess.err("can't perform LTO when compiling incrementally");
1244 // Since we don't know if code in an rlib will be linked to statically or
1245 // dynamically downstream, rustc generates `__imp_` symbols that help the
1246 // MSVC linker deal with this lack of knowledge (#27438). Unfortunately,
1247 // these manually generated symbols confuse LLD when it tries to merge
1248 // bitcode during ThinLTO. Therefore we disallow dynamic linking on MSVC
1249 // when compiling for LLD ThinLTO. This way we can validly just not generate
1250 // the `dllimport` attributes and `__imp_` symbols in that case.
1251 if sess.opts.debugging_opts.cross_lang_lto.enabled() &&
1252 sess.opts.cg.prefer_dynamic &&
1253 sess.target.target.options.is_like_msvc {
1254 sess.err("Linker plugin based LTO is not supported together with \
1255 `-C prefer-dynamic` when targeting MSVC");
1259 /// Hash value constructed out of all the `-C metadata` arguments passed to the
1260 /// compiler. Together with the crate-name forms a unique global identifier for
1262 #[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy, RustcEncodable, RustcDecodable)]
1263 pub struct CrateDisambiguator(Fingerprint);
1265 impl CrateDisambiguator {
1266 pub fn to_fingerprint(self) -> Fingerprint {
1271 impl fmt::Display for CrateDisambiguator {
1272 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
1273 let (a, b) = self.0.as_value();
1274 let as_u128 = a as u128 | ((b as u128) << 64);
1275 f.write_str(&base_n::encode(as_u128, base_n::CASE_INSENSITIVE))
1279 impl From<Fingerprint> for CrateDisambiguator {
1280 fn from(fingerprint: Fingerprint) -> CrateDisambiguator {
1281 CrateDisambiguator(fingerprint)
1285 impl_stable_hash_via_hash!(CrateDisambiguator);
1287 /// Holds data on the current incremental compilation session, if there is one.
1289 pub enum IncrCompSession {
1290 /// This is the state the session will be in until the incr. comp. dir is
1293 /// This is the state during which the session directory is private and can
1296 session_directory: PathBuf,
1297 lock_file: flock::Lock,
1298 load_dep_graph: bool,
1300 /// This is the state after the session directory has been finalized. In this
1301 /// state, the contents of the directory must not be modified any more.
1302 Finalized { session_directory: PathBuf },
1303 /// This is an error state that is reached when some compilation error has
1304 /// occurred. It indicates that the contents of the session directory must
1305 /// not be used, since they might be invalid.
1306 InvalidBecauseOfErrors { session_directory: PathBuf },
1309 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
1310 let emitter: Box<dyn Emitter + sync::Send> = match output {
1311 config::ErrorOutputType::HumanReadable(color_config) => {
1312 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1314 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1315 config::ErrorOutputType::Short(color_config) => {
1316 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1319 let handler = errors::Handler::with_emitter(true, false, emitter);
1320 handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal);
1321 errors::FatalError.raise();
1324 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
1325 let emitter: Box<dyn Emitter + sync::Send> = match output {
1326 config::ErrorOutputType::HumanReadable(color_config) => {
1327 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1329 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1330 config::ErrorOutputType::Short(color_config) => {
1331 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1334 let handler = errors::Handler::with_emitter(true, false, emitter);
1335 handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
1338 #[derive(Copy, Clone, Debug)]
1339 pub enum CompileIncomplete {
1341 Errored(ErrorReported),
1343 impl From<ErrorReported> for CompileIncomplete {
1344 fn from(err: ErrorReported) -> CompileIncomplete {
1345 CompileIncomplete::Errored(err)
1348 pub type CompileResult = Result<(), CompileIncomplete>;
1350 pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
1354 Err(CompileIncomplete::Errored(ErrorReported))