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::parse::{self, ParseSess};
39 use syntax_pos::{MultiSpan, Span};
40 use util::profiling::SelfProfiler;
42 use rustc_target::spec::{PanicStrategy, RelroLevel, Target, TargetTriple};
43 use rustc_data_structures::flock;
44 use jobserver::Client;
47 use std::cell::{self, Cell, RefCell};
51 use std::path::{Path, PathBuf};
52 use std::time::Duration;
54 use std::sync::atomic::{AtomicUsize, Ordering};
61 /// Represents the data associated with a compilation
62 /// session for a single crate.
64 pub target: config::Config,
66 pub opts: config::Options,
67 pub parse_sess: ParseSess,
68 /// For a library crate, this is always none
69 pub entry_fn: Once<Option<(NodeId, Span, config::EntryFnType)>>,
70 pub plugin_registrar_fn: Once<Option<ast::NodeId>>,
71 pub derive_registrar_fn: Once<Option<ast::NodeId>>,
72 pub default_sysroot: Option<PathBuf>,
73 /// The name of the root source file of the crate, in the local file system.
74 /// `None` means that there is no source file.
75 pub local_crate_source_file: Option<PathBuf>,
76 /// The directory the compiler has been executed in plus a flag indicating
77 /// if the value stored here has been affected by path remapping.
78 pub working_dir: (PathBuf, bool),
80 // FIXME: lint_store and buffered_lints are not thread-safe,
81 // but are only used in a single thread
82 pub lint_store: RwLock<lint::LintStore>,
83 pub buffered_lints: Lock<Option<lint::LintBuffer>>,
85 /// Set of (DiagnosticId, Option<Span>, message) tuples tracking
86 /// (sub)diagnostics that have been set once, but should not be set again,
87 /// in order to avoid redundantly verbose output (Issue #24690, #44953).
88 pub one_time_diagnostics: Lock<FxHashSet<(DiagnosticMessageId, Option<Span>, String)>>,
89 pub plugin_llvm_passes: OneThread<RefCell<Vec<String>>>,
90 pub plugin_attributes: OneThread<RefCell<Vec<(String, AttributeType)>>>,
91 pub crate_types: Once<Vec<config::CrateType>>,
92 pub dependency_formats: Once<dependency_format::Dependencies>,
93 /// The crate_disambiguator is constructed out of all the `-C metadata`
94 /// arguments passed to the compiler. Its value together with the crate-name
95 /// forms a unique global identifier for the crate. It is used to allow
96 /// multiple crates with the same name to coexist. See the
97 /// rustc_codegen_llvm::back::symbol_names module for more information.
98 pub crate_disambiguator: Once<CrateDisambiguator>,
100 features: Once<feature_gate::Features>,
102 /// The maximum recursion limit for potentially infinitely recursive
103 /// operations such as auto-dereference and monomorphization.
104 pub recursion_limit: Once<usize>,
106 /// The maximum length of types during monomorphization.
107 pub type_length_limit: Once<usize>,
109 /// The maximum number of stackframes allowed in const eval
110 pub const_eval_stack_frame_limit: usize,
112 /// The metadata::creader module may inject an allocator/panic_runtime
113 /// dependency if it didn't already find one, and this tracks what was
115 pub injected_allocator: Once<Option<CrateNum>>,
116 pub allocator_kind: Once<Option<AllocatorKind>>,
117 pub injected_panic_runtime: Once<Option<CrateNum>>,
119 /// Map from imported macro spans (which consist of
120 /// the localized span for the macro body) to the
121 /// macro name and definition span in the source crate.
122 pub imported_macro_spans: OneThread<RefCell<FxHashMap<Span, (String, Span)>>>,
124 incr_comp_session: OneThread<RefCell<IncrCompSession>>,
125 /// Used for incremental compilation tests. Will only be populated if
126 /// `-Zquery-dep-graph` is specified.
127 pub cgu_reuse_tracker: CguReuseTracker,
129 /// Used by -Z profile-queries in util::common
130 pub profile_channel: Lock<Option<mpsc::Sender<ProfileQueriesMsg>>>,
132 /// Used by -Z self-profile
133 pub self_profiling: Lock<SelfProfiler>,
135 /// Some measurements that are being gathered during compilation.
136 pub perf_stats: PerfStats,
138 /// Data about code being compiled, gathered during compilation.
139 pub code_stats: Lock<CodeStats>,
141 next_node_id: OneThread<Cell<ast::NodeId>>,
143 /// If -zfuel=crate=n is specified, Some(crate).
144 optimization_fuel_crate: Option<String>,
145 /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0.
146 optimization_fuel_limit: LockCell<u64>,
147 /// We're rejecting all further optimizations.
148 out_of_fuel: LockCell<bool>,
150 // The next two are public because the driver needs to read them.
151 /// If -zprint-fuel=crate, Some(crate).
152 pub print_fuel_crate: Option<String>,
153 /// Always set to zero and incremented so that we can print fuel expended by a crate.
154 pub print_fuel: LockCell<u64>,
156 /// Loaded up early on in the initialization of this `Session` to avoid
157 /// false positives about a job server in our environment.
158 pub jobserver: Client,
160 /// Metadata about the allocators for the current crate being compiled
161 pub has_global_allocator: Once<bool>,
163 /// Metadata about the panic handlers for the current crate being compiled
164 pub has_panic_handler: Once<bool>,
166 /// Cap lint level specified by a driver specifically.
167 pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
170 pub struct PerfStats {
171 /// The accumulated time spent on computing symbol hashes
172 pub symbol_hash_time: Lock<Duration>,
173 /// The accumulated time spent decoding def path tables from metadata
174 pub decode_def_path_tables_time: Lock<Duration>,
175 /// Total number of values canonicalized queries constructed.
176 pub queries_canonicalized: AtomicUsize,
177 /// Number of times this query is invoked.
178 pub normalize_ty_after_erasing_regions: AtomicUsize,
179 /// Number of times this query is invoked.
180 pub normalize_projection_ty: AtomicUsize,
183 /// Enum to support dispatch of one-time diagnostics (in Session.diag_once)
184 enum DiagnosticBuilderMethod {
187 SpanSuggestion(String), // suggestion
188 // add more variants as needed to support one-time diagnostics
191 /// Diagnostic message ID—used by `Session.one_time_diagnostics` to avoid
192 /// emitting the same message more than once
193 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
194 pub enum DiagnosticMessageId {
195 ErrorId(u16), // EXXXX error code as integer
196 LintId(lint::LintId),
197 StabilityId(u32), // issue number
200 impl From<&'static lint::Lint> for DiagnosticMessageId {
201 fn from(lint: &'static lint::Lint) -> Self {
202 DiagnosticMessageId::LintId(lint::LintId::of(lint))
207 pub fn local_crate_disambiguator(&self) -> CrateDisambiguator {
208 *self.crate_disambiguator.get()
211 pub fn struct_span_warn<'a, S: Into<MultiSpan>>(
215 ) -> DiagnosticBuilder<'a> {
216 self.diagnostic().struct_span_warn(sp, msg)
218 pub fn struct_span_warn_with_code<'a, S: Into<MultiSpan>>(
223 ) -> DiagnosticBuilder<'a> {
224 self.diagnostic().struct_span_warn_with_code(sp, msg, code)
226 pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
227 self.diagnostic().struct_warn(msg)
229 pub fn struct_span_err<'a, S: Into<MultiSpan>>(
233 ) -> DiagnosticBuilder<'a> {
234 self.diagnostic().struct_span_err(sp, msg)
236 pub fn struct_span_err_with_code<'a, S: Into<MultiSpan>>(
241 ) -> DiagnosticBuilder<'a> {
242 self.diagnostic().struct_span_err_with_code(sp, msg, code)
244 // FIXME: This method should be removed (every error should have an associated error code).
245 pub fn struct_err<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
246 self.diagnostic().struct_err(msg)
248 pub fn struct_err_with_code<'a>(
252 ) -> DiagnosticBuilder<'a> {
253 self.diagnostic().struct_err_with_code(msg, code)
255 pub fn struct_span_fatal<'a, S: Into<MultiSpan>>(
259 ) -> DiagnosticBuilder<'a> {
260 self.diagnostic().struct_span_fatal(sp, msg)
262 pub fn struct_span_fatal_with_code<'a, S: Into<MultiSpan>>(
267 ) -> DiagnosticBuilder<'a> {
268 self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
270 pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> {
271 self.diagnostic().struct_fatal(msg)
274 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
275 self.diagnostic().span_fatal(sp, msg).raise()
277 pub fn span_fatal_with_code<S: Into<MultiSpan>>(
284 .span_fatal_with_code(sp, msg, code)
287 pub fn fatal(&self, msg: &str) -> ! {
288 self.diagnostic().fatal(msg).raise()
290 pub fn span_err_or_warn<S: Into<MultiSpan>>(&self, is_warning: bool, sp: S, msg: &str) {
292 self.span_warn(sp, msg);
294 self.span_err(sp, msg);
297 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
298 self.diagnostic().span_err(sp, msg)
300 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
301 self.diagnostic().span_err_with_code(sp, &msg, code)
303 pub fn err(&self, msg: &str) {
304 self.diagnostic().err(msg)
306 pub fn err_count(&self) -> usize {
307 self.diagnostic().err_count()
309 pub fn has_errors(&self) -> bool {
310 self.diagnostic().has_errors()
312 pub fn abort_if_errors(&self) {
313 self.diagnostic().abort_if_errors();
315 pub fn compile_status(&self) -> Result<(), CompileIncomplete> {
316 compile_result_from_err_count(self.err_count())
318 pub fn track_errors<F, T>(&self, f: F) -> Result<T, ErrorReported>
322 let old_count = self.err_count();
324 let errors = self.err_count() - old_count;
331 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
332 self.diagnostic().span_warn(sp, msg)
334 pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
335 self.diagnostic().span_warn_with_code(sp, msg, code)
337 pub fn warn(&self, msg: &str) {
338 self.diagnostic().warn(msg)
340 pub fn opt_span_warn<S: Into<MultiSpan>>(&self, opt_sp: Option<S>, msg: &str) {
342 Some(sp) => self.span_warn(sp, msg),
343 None => self.warn(msg),
346 /// Delay a span_bug() call until abort_if_errors()
347 pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
348 self.diagnostic().delay_span_bug(sp, msg)
350 pub fn note_without_error(&self, msg: &str) {
351 self.diagnostic().note_without_error(msg)
353 pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
354 self.diagnostic().span_note_without_error(sp, msg)
356 pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
357 self.diagnostic().span_unimpl(sp, msg)
359 pub fn unimpl(&self, msg: &str) -> ! {
360 self.diagnostic().unimpl(msg)
363 pub fn buffer_lint<S: Into<MultiSpan>>(
365 lint: &'static lint::Lint,
370 match *self.buffered_lints.borrow_mut() {
371 Some(ref mut buffer) => {
372 buffer.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal)
374 None => bug!("can't buffer lints after HIR lowering"),
378 pub fn buffer_lint_with_diagnostic<S: Into<MultiSpan>>(
380 lint: &'static lint::Lint,
384 diagnostic: BuiltinLintDiagnostics,
386 match *self.buffered_lints.borrow_mut() {
387 Some(ref mut buffer) => buffer.add_lint(lint, id, sp.into(), msg, diagnostic),
388 None => bug!("can't buffer lints after HIR lowering"),
392 pub fn reserve_node_ids(&self, count: usize) -> ast::NodeId {
393 let id = self.next_node_id.get();
395 match id.as_usize().checked_add(count) {
397 self.next_node_id.set(ast::NodeId::new(next));
399 None => bug!("Input too large, ran out of node ids!"),
404 pub fn next_node_id(&self) -> NodeId {
405 self.reserve_node_ids(1)
407 pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler {
408 &self.parse_sess.span_diagnostic
411 /// Analogous to calling methods on the given `DiagnosticBuilder`, but
412 /// deduplicates on lint ID, span (if any), and message for this `Session`
413 fn diag_once<'a, 'b>(
415 diag_builder: &'b mut DiagnosticBuilder<'a>,
416 method: DiagnosticBuilderMethod,
417 msg_id: DiagnosticMessageId,
419 span_maybe: Option<Span>,
421 let id_span_message = (msg_id, span_maybe, message.to_owned());
422 let fresh = self.one_time_diagnostics
424 .insert(id_span_message);
427 DiagnosticBuilderMethod::Note => {
428 diag_builder.note(message);
430 DiagnosticBuilderMethod::SpanNote => {
431 let span = span_maybe.expect("span_note needs a span");
432 diag_builder.span_note(span, message);
434 DiagnosticBuilderMethod::SpanSuggestion(suggestion) => {
435 let span = span_maybe.expect("span_suggestion_* needs a span");
436 diag_builder.span_suggestion_with_applicability(
440 Applicability::Unspecified,
447 pub fn diag_span_note_once<'a, 'b>(
449 diag_builder: &'b mut DiagnosticBuilder<'a>,
450 msg_id: DiagnosticMessageId,
456 DiagnosticBuilderMethod::SpanNote,
463 pub fn diag_note_once<'a, 'b>(
465 diag_builder: &'b mut DiagnosticBuilder<'a>,
466 msg_id: DiagnosticMessageId,
471 DiagnosticBuilderMethod::Note,
478 pub fn diag_span_suggestion_once<'a, 'b>(
480 diag_builder: &'b mut DiagnosticBuilder<'a>,
481 msg_id: DiagnosticMessageId,
488 DiagnosticBuilderMethod::SpanSuggestion(suggestion),
495 pub fn source_map<'a>(&'a self) -> &'a source_map::SourceMap {
496 self.parse_sess.source_map()
498 pub fn verbose(&self) -> bool {
499 self.opts.debugging_opts.verbose
501 pub fn time_passes(&self) -> bool {
502 self.opts.debugging_opts.time_passes
504 pub fn profile_queries(&self) -> bool {
505 self.opts.debugging_opts.profile_queries
506 || self.opts.debugging_opts.profile_queries_and_keys
508 pub fn profile_queries_and_keys(&self) -> bool {
509 self.opts.debugging_opts.profile_queries_and_keys
511 pub fn count_llvm_insns(&self) -> bool {
512 self.opts.debugging_opts.count_llvm_insns
514 pub fn time_llvm_passes(&self) -> bool {
515 self.opts.debugging_opts.time_llvm_passes
517 pub fn codegen_stats(&self) -> bool {
518 self.opts.debugging_opts.codegen_stats
520 pub fn meta_stats(&self) -> bool {
521 self.opts.debugging_opts.meta_stats
523 pub fn asm_comments(&self) -> bool {
524 self.opts.debugging_opts.asm_comments
526 pub fn verify_llvm_ir(&self) -> bool {
527 self.opts.debugging_opts.verify_llvm_ir
528 || cfg!(always_verify_llvm_ir)
530 pub fn borrowck_stats(&self) -> bool {
531 self.opts.debugging_opts.borrowck_stats
533 pub fn print_llvm_passes(&self) -> bool {
534 self.opts.debugging_opts.print_llvm_passes
537 /// Get the features enabled for the current compilation session.
538 /// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents
539 /// dependency tracking. Use tcx.features() instead.
541 pub fn features_untracked(&self) -> &feature_gate::Features {
545 pub fn init_features(&self, features: feature_gate::Features) {
546 self.features.set(features);
549 /// Calculates the flavor of LTO to use for this compilation.
550 pub fn lto(&self) -> config::Lto {
551 // If our target has codegen requirements ignore the command line
552 if self.target.target.options.requires_lto {
553 return config::Lto::Fat;
556 // If the user specified something, return that. If they only said `-C
557 // lto` and we've for whatever reason forced off ThinLTO via the CLI,
558 // then ensure we can't use a ThinLTO.
559 match self.opts.cg.lto {
560 config::LtoCli::Unspecified => {
561 // The compiler was invoked without the `-Clto` flag. Fall
562 // through to the default handling
564 config::LtoCli::No => {
565 // The user explicitly opted out of any kind of LTO
566 return config::Lto::No;
568 config::LtoCli::Yes |
569 config::LtoCli::Fat |
570 config::LtoCli::NoParam => {
571 // All of these mean fat LTO
572 return config::Lto::Fat;
574 config::LtoCli::Thin => {
575 return if self.opts.cli_forced_thinlto_off {
583 // Ok at this point the target doesn't require anything and the user
584 // hasn't asked for anything. Our next decision is whether or not
585 // we enable "auto" ThinLTO where we use multiple codegen units and
586 // then do ThinLTO over those codegen units. The logic below will
587 // either return `No` or `ThinLocal`.
589 // If processing command line options determined that we're incompatible
590 // with ThinLTO (e.g. `-C lto --emit llvm-ir`) then return that option.
591 if self.opts.cli_forced_thinlto_off {
592 return config::Lto::No;
595 // If `-Z thinlto` specified process that, but note that this is mostly
596 // a deprecated option now that `-C lto=thin` exists.
597 if let Some(enabled) = self.opts.debugging_opts.thinlto {
599 return config::Lto::ThinLocal;
601 return config::Lto::No;
605 // If there's only one codegen unit and LTO isn't enabled then there's
606 // no need for ThinLTO so just return false.
607 if self.codegen_units() == 1 {
608 return config::Lto::No;
611 // Now we're in "defaults" territory. By default we enable ThinLTO for
612 // optimized compiles (anything greater than O0).
613 match self.opts.optimize {
614 config::OptLevel::No => config::Lto::No,
615 _ => config::Lto::ThinLocal,
619 /// Returns the panic strategy for this compile session. If the user explicitly selected one
620 /// using '-C panic', use that, otherwise use the panic strategy defined by the target.
621 pub fn panic_strategy(&self) -> PanicStrategy {
625 .unwrap_or(self.target.target.options.panic_strategy)
627 pub fn fewer_names(&self) -> bool {
628 let more_names = self.opts
630 .contains_key(&OutputType::LlvmAssembly)
631 || self.opts.output_types.contains_key(&OutputType::Bitcode);
632 self.opts.debugging_opts.fewer_names || !more_names
635 pub fn no_landing_pads(&self) -> bool {
636 self.opts.debugging_opts.no_landing_pads || self.panic_strategy() == PanicStrategy::Abort
638 pub fn unstable_options(&self) -> bool {
639 self.opts.debugging_opts.unstable_options
641 pub fn overflow_checks(&self) -> bool {
645 .or(self.opts.debugging_opts.force_overflow_checks)
646 .unwrap_or(self.opts.debug_assertions)
649 pub fn crt_static(&self) -> bool {
650 // If the target does not opt in to crt-static support, use its default.
651 if self.target.target.options.crt_static_respected {
652 self.crt_static_feature()
654 self.target.target.options.crt_static_default
658 pub fn crt_static_feature(&self) -> bool {
659 let requested_features = self.opts.cg.target_feature.split(',');
660 let found_negative = requested_features.clone().any(|r| r == "-crt-static");
661 let found_positive = requested_features.clone().any(|r| r == "+crt-static");
663 // If the target we're compiling for requests a static crt by default,
664 // then see if the `-crt-static` feature was passed to disable that.
665 // Otherwise if we don't have a static crt by default then see if the
666 // `+crt-static` feature was passed.
667 if self.target.target.options.crt_static_default {
674 pub fn must_not_eliminate_frame_pointers(&self) -> bool {
675 if let Some(x) = self.opts.cg.force_frame_pointers {
678 !self.target.target.options.eliminate_frame_pointer
682 /// Returns the symbol name for the registrar function,
683 /// given the crate Svh and the function DefIndex.
684 pub fn generate_plugin_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
686 "__rustc_plugin_registrar_{}__",
687 disambiguator.to_fingerprint().to_hex()
691 pub fn generate_derive_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
693 "__rustc_derive_registrar_{}__",
694 disambiguator.to_fingerprint().to_hex()
698 pub fn sysroot<'a>(&'a self) -> &'a Path {
699 match self.opts.maybe_sysroot {
700 Some(ref sysroot) => sysroot,
701 None => self.default_sysroot
703 .expect("missing sysroot and default_sysroot in Session"),
706 pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
707 filesearch::FileSearch::new(
709 self.opts.target_triple.triple(),
710 &self.opts.search_paths,
714 pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
715 filesearch::FileSearch::new(
717 config::host_triple(),
718 &self.opts.search_paths,
723 pub fn set_incr_session_load_dep_graph(&self, load: bool) {
724 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
726 if let IncrCompSession::Active { ref mut load_dep_graph, .. } = *incr_comp_session {
727 *load_dep_graph = load;
731 pub fn incr_session_load_dep_graph(&self) -> bool {
732 let incr_comp_session = self.incr_comp_session.borrow();
733 match *incr_comp_session {
734 IncrCompSession::Active { load_dep_graph, .. } => load_dep_graph,
739 pub fn init_incr_comp_session(
741 session_dir: PathBuf,
742 lock_file: flock::Lock,
743 load_dep_graph: bool,
745 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
747 if let IncrCompSession::NotInitialized = *incr_comp_session {
750 "Trying to initialize IncrCompSession `{:?}`",
755 *incr_comp_session = IncrCompSession::Active {
756 session_directory: session_dir,
762 pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) {
763 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
765 if let IncrCompSession::Active { .. } = *incr_comp_session {
768 "Trying to finalize IncrCompSession `{:?}`",
773 // Note: This will also drop the lock file, thus unlocking the directory
774 *incr_comp_session = IncrCompSession::Finalized {
775 session_directory: new_directory_path,
779 pub fn mark_incr_comp_session_as_invalid(&self) {
780 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
782 let session_directory = match *incr_comp_session {
783 IncrCompSession::Active {
784 ref session_directory,
786 } => session_directory.clone(),
787 IncrCompSession::InvalidBecauseOfErrors { .. } => return,
789 "Trying to invalidate IncrCompSession `{:?}`",
794 // Note: This will also drop the lock file, thus unlocking the directory
795 *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors { session_directory };
798 pub fn incr_comp_session_dir(&self) -> cell::Ref<'_, PathBuf> {
799 let incr_comp_session = self.incr_comp_session.borrow();
802 |incr_comp_session| match *incr_comp_session {
803 IncrCompSession::NotInitialized => bug!(
804 "Trying to get session directory from IncrCompSession `{:?}`",
807 IncrCompSession::Active {
808 ref session_directory,
811 | IncrCompSession::Finalized {
812 ref session_directory,
814 | IncrCompSession::InvalidBecauseOfErrors {
815 ref session_directory,
816 } => session_directory,
821 pub fn incr_comp_session_dir_opt(&self) -> Option<cell::Ref<'_, PathBuf>> {
822 if self.opts.incremental.is_some() {
823 Some(self.incr_comp_session_dir())
829 pub fn profiler<F: FnOnce(&mut SelfProfiler) -> ()>(&self, f: F) {
830 let mut profiler = self.self_profiling.borrow_mut();
834 pub fn print_profiler_results(&self) {
835 let mut profiler = self.self_profiling.borrow_mut();
836 profiler.print_results(&self.opts);
839 pub fn save_json_results(&self) {
840 let profiler = self.self_profiling.borrow();
841 profiler.save_results(&self.opts);
844 pub fn print_perf_stats(&self) {
846 "Total time spent computing symbol hashes: {}",
847 duration_to_secs_str(*self.perf_stats.symbol_hash_time.lock())
850 "Total time spent decoding DefPath tables: {}",
851 duration_to_secs_str(*self.perf_stats.decode_def_path_tables_time.lock())
853 println!("Total queries canonicalized: {}",
854 self.perf_stats.queries_canonicalized.load(Ordering::Relaxed));
855 println!("normalize_ty_after_erasing_regions: {}",
856 self.perf_stats.normalize_ty_after_erasing_regions.load(Ordering::Relaxed));
857 println!("normalize_projection_ty: {}",
858 self.perf_stats.normalize_projection_ty.load(Ordering::Relaxed));
861 /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
862 /// This expends fuel if applicable, and records fuel if applicable.
863 pub fn consider_optimizing<T: Fn() -> String>(&self, crate_name: &str, msg: T) -> bool {
865 if let Some(ref c) = self.optimization_fuel_crate {
867 assert_eq!(self.query_threads(), 1);
868 let fuel = self.optimization_fuel_limit.get();
870 if fuel == 0 && !self.out_of_fuel.get() {
871 println!("optimization-fuel-exhausted: {}", msg());
872 self.out_of_fuel.set(true);
874 self.optimization_fuel_limit.set(fuel - 1);
878 if let Some(ref c) = self.print_fuel_crate {
880 assert_eq!(self.query_threads(), 1);
881 self.print_fuel.set(self.print_fuel.get() + 1);
887 /// Returns the number of query threads that should be used for this
889 pub fn query_threads_from_opts(opts: &config::Options) -> usize {
890 opts.debugging_opts.query_threads.unwrap_or(1)
893 /// Returns the number of query threads that should be used for this
895 pub fn query_threads(&self) -> usize {
896 Self::query_threads_from_opts(&self.opts)
899 /// Returns the number of codegen units that should be used for this
901 pub fn codegen_units(&self) -> usize {
902 if let Some(n) = self.opts.cli_forced_codegen_units {
905 if let Some(n) = self.target.target.options.default_codegen_units {
909 // Why is 16 codegen units the default all the time?
911 // The main reason for enabling multiple codegen units by default is to
912 // leverage the ability for the codegen backend to do codegen and
913 // optimization in parallel. This allows us, especially for large crates, to
914 // make good use of all available resources on the machine once we've
915 // hit that stage of compilation. Large crates especially then often
916 // take a long time in codegen/optimization and this helps us amortize that
919 // Note that a high number here doesn't mean that we'll be spawning a
920 // large number of threads in parallel. The backend of rustc contains
921 // global rate limiting through the `jobserver` crate so we'll never
922 // overload the system with too much work, but rather we'll only be
923 // optimizing when we're otherwise cooperating with other instances of
926 // Rather a high number here means that we should be able to keep a lot
927 // of idle cpus busy. By ensuring that no codegen unit takes *too* long
928 // to build we'll be guaranteed that all cpus will finish pretty closely
929 // to one another and we should make relatively optimal use of system
932 // Note that the main cost of codegen units is that it prevents LLVM
933 // from inlining across codegen units. Users in general don't have a lot
934 // of control over how codegen units are split up so it's our job in the
935 // compiler to ensure that undue performance isn't lost when using
936 // codegen units (aka we can't require everyone to slap `#[inline]` on
939 // If we're compiling at `-O0` then the number doesn't really matter too
940 // much because performance doesn't matter and inlining is ok to lose.
941 // In debug mode we just want to try to guarantee that no cpu is stuck
942 // doing work that could otherwise be farmed to others.
944 // In release mode, however (O1 and above) performance does indeed
945 // matter! To recover the loss in performance due to inlining we'll be
946 // enabling ThinLTO by default (the function for which is just below).
947 // This will ensure that we recover any inlining wins we otherwise lost
948 // through codegen unit partitioning.
952 // Ok that's a lot of words but the basic tl;dr; is that we want a high
953 // number here -- but not too high. Additionally we're "safe" to have it
954 // always at the same number at all optimization levels.
956 // As a result 16 was chosen here! Mostly because it was a power of 2
957 // and most benchmarks agreed it was roughly a local optimum. Not very
962 pub fn teach(&self, code: &DiagnosticId) -> bool {
963 self.opts.debugging_opts.teach && self.diagnostic().must_teach(code)
966 /// Are we allowed to use features from the Rust 2018 edition?
967 pub fn rust_2018(&self) -> bool {
968 self.opts.edition >= Edition::Edition2018
971 pub fn edition(&self) -> Edition {
975 /// True if we cannot skip the PLT for shared library calls.
976 pub fn needs_plt(&self) -> bool {
977 // Check if the current target usually needs PLT to be enabled.
978 // The user can use the command line flag to override it.
979 let needs_plt = self.target.target.options.needs_plt;
981 let dbg_opts = &self.opts.debugging_opts;
983 let relro_level = dbg_opts.relro_level
984 .unwrap_or(self.target.target.options.relro_level);
986 // Only enable this optimization by default if full relro is also enabled.
987 // In this case, lazy binding was already unavailable, so nothing is lost.
988 // This also ensures `-Wl,-z,now` is supported by the linker.
989 let full_relro = RelroLevel::Full == relro_level;
991 // If user didn't explicitly forced us to use / skip the PLT,
992 // then try to skip it where possible.
993 dbg_opts.plt.unwrap_or(needs_plt || !full_relro)
997 pub fn build_session(
998 sopts: config::Options,
999 local_crate_source_file: Option<PathBuf>,
1000 registry: errors::registry::Registry,
1002 let file_path_mapping = sopts.file_path_mapping();
1004 build_session_with_source_map(
1006 local_crate_source_file,
1008 Lrc::new(source_map::SourceMap::new(file_path_mapping)),
1013 pub fn build_session_with_source_map(
1014 sopts: config::Options,
1015 local_crate_source_file: Option<PathBuf>,
1016 registry: errors::registry::Registry,
1017 source_map: Lrc<source_map::SourceMap>,
1018 emitter_dest: Option<Box<dyn Write + Send>>,
1020 // FIXME: This is not general enough to make the warning lint completely override
1021 // normal diagnostic warnings, since the warning lint can also be denied and changed
1022 // later via the source code.
1023 let warnings_allow = sopts
1026 .filter(|&&(ref key, _)| *key == "warnings")
1027 .map(|&(_, ref level)| *level == lint::Allow)
1030 let cap_lints_allow = sopts.lint_cap.map_or(false, |cap| cap == lint::Allow);
1032 let can_emit_warnings = !(warnings_allow || cap_lints_allow);
1034 let treat_err_as_bug = sopts.debugging_opts.treat_err_as_bug;
1035 let dont_buffer_diagnostics = sopts.debugging_opts.dont_buffer_diagnostics;
1036 let report_delayed_bugs = sopts.debugging_opts.report_delayed_bugs;
1038 let external_macro_backtrace = sopts.debugging_opts.external_macro_backtrace;
1040 let emitter: Box<dyn Emitter + sync::Send> =
1041 match (sopts.error_format, emitter_dest) {
1042 (config::ErrorOutputType::HumanReadable(color_config), None) => Box::new(
1043 EmitterWriter::stderr(
1045 Some(source_map.clone()),
1047 sopts.debugging_opts.teach,
1048 ).ui_testing(sopts.debugging_opts.ui_testing),
1050 (config::ErrorOutputType::HumanReadable(_), Some(dst)) => Box::new(
1051 EmitterWriter::new(dst, Some(source_map.clone()), false, false)
1052 .ui_testing(sopts.debugging_opts.ui_testing),
1054 (config::ErrorOutputType::Json(pretty), None) => Box::new(
1055 JsonEmitter::stderr(
1059 ).ui_testing(sopts.debugging_opts.ui_testing),
1061 (config::ErrorOutputType::Json(pretty), Some(dst)) => Box::new(
1067 ).ui_testing(sopts.debugging_opts.ui_testing),
1069 (config::ErrorOutputType::Short(color_config), None) => Box::new(
1070 EmitterWriter::stderr(color_config, Some(source_map.clone()), true, false),
1072 (config::ErrorOutputType::Short(_), Some(dst)) => {
1073 Box::new(EmitterWriter::new(dst, Some(source_map.clone()), true, false))
1077 let diagnostic_handler = errors::Handler::with_emitter_and_flags(
1079 errors::HandlerFlags {
1082 report_delayed_bugs,
1083 dont_buffer_diagnostics,
1084 external_macro_backtrace,
1085 ..Default::default()
1089 build_session_(sopts, local_crate_source_file, diagnostic_handler, source_map)
1092 pub fn build_session_(
1093 sopts: config::Options,
1094 local_crate_source_file: Option<PathBuf>,
1095 span_diagnostic: errors::Handler,
1096 source_map: Lrc<source_map::SourceMap>,
1098 let host_triple = TargetTriple::from_triple(config::host_triple());
1099 let host = Target::search(&host_triple).unwrap_or_else(|e|
1101 .fatal(&format!("Error loading host specification: {}", e))
1104 let target_cfg = config::build_target_config(&sopts, &span_diagnostic);
1106 let p_s = parse::ParseSess::with_span_handler(span_diagnostic, source_map);
1107 let default_sysroot = match sopts.maybe_sysroot {
1109 None => Some(filesearch::get_or_default_sysroot()),
1112 let file_path_mapping = sopts.file_path_mapping();
1114 let local_crate_source_file =
1115 local_crate_source_file.map(|path| file_path_mapping.map_prefix(path).0);
1117 let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone());
1118 let optimization_fuel_limit =
1119 LockCell::new(sopts.debugging_opts.fuel.as_ref().map(|i| i.1).unwrap_or(0));
1120 let print_fuel_crate = sopts.debugging_opts.print_fuel.clone();
1121 let print_fuel = LockCell::new(0);
1123 let working_dir = env::current_dir().unwrap_or_else(|e|
1125 .fatal(&format!("Current directory is invalid: {}", e))
1128 let working_dir = file_path_mapping.map_prefix(working_dir);
1130 let cgu_reuse_tracker = if sopts.debugging_opts.query_dep_graph {
1131 CguReuseTracker::new()
1133 CguReuseTracker::new_disabled()
1136 let sess = Session {
1141 // For a library crate, this is always none
1142 entry_fn: Once::new(),
1143 plugin_registrar_fn: Once::new(),
1144 derive_registrar_fn: Once::new(),
1146 local_crate_source_file,
1148 lint_store: RwLock::new(lint::LintStore::new()),
1149 buffered_lints: Lock::new(Some(lint::LintBuffer::new())),
1150 one_time_diagnostics: Default::default(),
1151 plugin_llvm_passes: OneThread::new(RefCell::new(Vec::new())),
1152 plugin_attributes: OneThread::new(RefCell::new(Vec::new())),
1153 crate_types: Once::new(),
1154 dependency_formats: Once::new(),
1155 crate_disambiguator: Once::new(),
1156 features: Once::new(),
1157 recursion_limit: Once::new(),
1158 type_length_limit: Once::new(),
1159 const_eval_stack_frame_limit: 100,
1160 next_node_id: OneThread::new(Cell::new(NodeId::new(1))),
1161 injected_allocator: Once::new(),
1162 allocator_kind: Once::new(),
1163 injected_panic_runtime: Once::new(),
1164 imported_macro_spans: OneThread::new(RefCell::new(FxHashMap::default())),
1165 incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)),
1167 self_profiling: Lock::new(SelfProfiler::new()),
1168 profile_channel: Lock::new(None),
1169 perf_stats: PerfStats {
1170 symbol_hash_time: Lock::new(Duration::from_secs(0)),
1171 decode_def_path_tables_time: Lock::new(Duration::from_secs(0)),
1172 queries_canonicalized: AtomicUsize::new(0),
1173 normalize_ty_after_erasing_regions: AtomicUsize::new(0),
1174 normalize_projection_ty: AtomicUsize::new(0),
1176 code_stats: Default::default(),
1177 optimization_fuel_crate,
1178 optimization_fuel_limit,
1181 out_of_fuel: LockCell::new(false),
1182 // Note that this is unsafe because it may misinterpret file descriptors
1183 // on Unix as jobserver file descriptors. We hopefully execute this near
1184 // the beginning of the process though to ensure we don't get false
1185 // positives, or in other words we try to execute this before we open
1186 // any file descriptors ourselves.
1188 // Pick a "reasonable maximum" if we don't otherwise have
1189 // a jobserver in our environment, capping out at 32 so we
1190 // don't take everything down by hogging the process run queue.
1191 // The fixed number is used to have deterministic compilation
1194 // Also note that we stick this in a global because there could be
1195 // multiple `Session` instances in this process, and the jobserver is
1198 static mut GLOBAL_JOBSERVER: *mut Client = 0 as *mut _;
1199 static INIT: std::sync::Once = std::sync::ONCE_INIT;
1201 let client = Client::from_env().unwrap_or_else(|| {
1202 Client::new(32).expect("failed to create jobserver")
1204 GLOBAL_JOBSERVER = Box::into_raw(Box::new(client));
1206 (*GLOBAL_JOBSERVER).clone()
1208 has_global_allocator: Once::new(),
1209 has_panic_handler: Once::new(),
1210 driver_lint_caps: Default::default(),
1213 validate_commandline_args_with_session_available(&sess);
1218 // If it is useful to have a Session available already for validating a
1219 // commandline argument, you can do so here.
1220 fn validate_commandline_args_with_session_available(sess: &Session) {
1222 if sess.opts.incremental.is_some() {
1226 sess.err("can't perform LTO when compiling incrementally");
1235 // Since we don't know if code in an rlib will be linked to statically or
1236 // dynamically downstream, rustc generates `__imp_` symbols that help the
1237 // MSVC linker deal with this lack of knowledge (#27438). Unfortunately,
1238 // these manually generated symbols confuse LLD when it tries to merge
1239 // bitcode during ThinLTO. Therefore we disallow dynamic linking on MSVC
1240 // when compiling for LLD ThinLTO. This way we can validly just not generate
1241 // the `dllimport` attributes and `__imp_` symbols in that case.
1242 if sess.opts.debugging_opts.cross_lang_lto.enabled() &&
1243 sess.opts.cg.prefer_dynamic &&
1244 sess.target.target.options.is_like_msvc {
1245 sess.err("Linker plugin based LTO is not supported together with \
1246 `-C prefer-dynamic` when targeting MSVC");
1250 /// Hash value constructed out of all the `-C metadata` arguments passed to the
1251 /// compiler. Together with the crate-name forms a unique global identifier for
1253 #[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy, RustcEncodable, RustcDecodable)]
1254 pub struct CrateDisambiguator(Fingerprint);
1256 impl CrateDisambiguator {
1257 pub fn to_fingerprint(self) -> Fingerprint {
1262 impl fmt::Display for CrateDisambiguator {
1263 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
1264 let (a, b) = self.0.as_value();
1265 let as_u128 = a as u128 | ((b as u128) << 64);
1266 f.write_str(&base_n::encode(as_u128, base_n::CASE_INSENSITIVE))
1270 impl From<Fingerprint> for CrateDisambiguator {
1271 fn from(fingerprint: Fingerprint) -> CrateDisambiguator {
1272 CrateDisambiguator(fingerprint)
1276 impl_stable_hash_via_hash!(CrateDisambiguator);
1278 /// Holds data on the current incremental compilation session, if there is one.
1280 pub enum IncrCompSession {
1281 /// This is the state the session will be in until the incr. comp. dir is
1284 /// This is the state during which the session directory is private and can
1287 session_directory: PathBuf,
1288 lock_file: flock::Lock,
1289 load_dep_graph: bool,
1291 /// This is the state after the session directory has been finalized. In this
1292 /// state, the contents of the directory must not be modified any more.
1293 Finalized { session_directory: PathBuf },
1294 /// This is an error state that is reached when some compilation error has
1295 /// occurred. It indicates that the contents of the session directory must
1296 /// not be used, since they might be invalid.
1297 InvalidBecauseOfErrors { session_directory: PathBuf },
1300 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
1301 let emitter: Box<dyn Emitter + sync::Send> = match output {
1302 config::ErrorOutputType::HumanReadable(color_config) => {
1303 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1305 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1306 config::ErrorOutputType::Short(color_config) => {
1307 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1310 let handler = errors::Handler::with_emitter(true, false, emitter);
1311 handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal);
1312 errors::FatalError.raise();
1315 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
1316 let emitter: Box<dyn Emitter + sync::Send> = match output {
1317 config::ErrorOutputType::HumanReadable(color_config) => {
1318 Box::new(EmitterWriter::stderr(color_config, None, false, false))
1320 config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)),
1321 config::ErrorOutputType::Short(color_config) => {
1322 Box::new(EmitterWriter::stderr(color_config, None, true, false))
1325 let handler = errors::Handler::with_emitter(true, false, emitter);
1326 handler.emit(&MultiSpan::new(), msg, errors::Level::Warning);
1329 #[derive(Copy, Clone, Debug)]
1330 pub enum CompileIncomplete {
1332 Errored(ErrorReported),
1334 impl From<ErrorReported> for CompileIncomplete {
1335 fn from(err: ErrorReported) -> CompileIncomplete {
1336 CompileIncomplete::Errored(err)
1339 pub type CompileResult = Result<(), CompileIncomplete>;
1341 pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
1345 Err(CompileIncomplete::Errored(ErrorReported))