1 use crate::cgu_reuse_tracker::CguReuseTracker;
2 use crate::code_stats::CodeStats;
3 pub use crate::code_stats::{DataTypeKind, FieldInfo, SizeKind, VariantInfo};
4 use crate::config::{self, CrateType, OutputType, PrintRequest, SwitchWithOptPath};
6 use crate::lint::{self, LintId};
7 use crate::parse::ParseSess;
8 use crate::search_paths::{PathKind, SearchPath};
10 pub use rustc_ast::attr::MarkedAttrs;
11 pub use rustc_ast::Attribute;
12 use rustc_data_structures::flock;
13 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
14 use rustc_data_structures::jobserver::{self, Client};
15 use rustc_data_structures::profiling::{duration_to_secs_str, SelfProfiler, SelfProfilerRef};
16 use rustc_data_structures::sync::{
17 self, AtomicU64, AtomicUsize, Lock, Lrc, OnceCell, OneThread, Ordering, Ordering::SeqCst,
19 use rustc_errors::annotate_snippet_emitter_writer::AnnotateSnippetEmitterWriter;
20 use rustc_errors::emitter::{Emitter, EmitterWriter, HumanReadableErrorType};
21 use rustc_errors::json::JsonEmitter;
22 use rustc_errors::registry::Registry;
23 use rustc_errors::{Diagnostic, DiagnosticBuilder, DiagnosticId, ErrorReported};
24 use rustc_lint_defs::FutureBreakage;
25 pub use rustc_span::crate_disambiguator::CrateDisambiguator;
26 use rustc_span::edition::Edition;
27 use rustc_span::source_map::{FileLoader, MultiSpan, RealFileLoader, SourceMap, Span};
28 use rustc_span::{sym, SourceFileHashAlgorithm, Symbol};
29 use rustc_target::asm::InlineAsmArch;
30 use rustc_target::spec::{CodeModel, PanicStrategy, RelocModel, RelroLevel};
31 use rustc_target::spec::{SanitizerSet, SplitDebuginfo, Target, TargetTriple, TlsModel};
33 use std::cell::{self, RefCell};
37 use std::num::NonZeroU32;
38 use std::ops::{Div, Mul};
39 use std::path::PathBuf;
40 use std::str::FromStr;
42 use std::time::Duration;
44 pub trait SessionLintStore: sync::Send + sync::Sync {
45 fn name_to_lint(&self, lint_name: &str) -> LintId;
48 pub struct OptimizationFuel {
49 /// If `-zfuel=crate=n` is specified, initially set to `n`, otherwise `0`.
51 /// We're rejecting all further optimizations.
55 /// The behavior of the CTFE engine when an error occurs with regards to backtraces.
56 #[derive(Clone, Copy)]
57 pub enum CtfeBacktrace {
58 /// Do nothing special, return the error as usual without a backtrace.
60 /// Capture a backtrace at the point the error is created and return it in the error
61 /// (to be printed later if/when the error ever actually gets shown to the user).
63 /// Capture a backtrace at the point the error is created and immediately print it out.
67 /// New-type wrapper around `usize` for representing limits. Ensures that comparisons against
68 /// limits are consistent throughout the compiler.
69 #[derive(Clone, Copy, Debug)]
70 pub struct Limit(pub usize);
73 /// Create a new limit from a `usize`.
74 pub fn new(value: usize) -> Self {
78 /// Check that `value` is within the limit. Ensures that the same comparisons are used
79 /// throughout the compiler, as mismatches can cause ICEs, see #72540.
81 pub fn value_within_limit(&self, value: usize) -> bool {
86 impl fmt::Display for Limit {
87 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
88 write!(f, "{}", self.0)
92 impl Div<usize> for Limit {
95 fn div(self, rhs: usize) -> Self::Output {
96 Limit::new(self.0 / rhs)
100 impl Mul<usize> for Limit {
103 fn mul(self, rhs: usize) -> Self::Output {
104 Limit::new(self.0 * rhs)
108 /// Represents the data associated with a compilation
109 /// session for a single crate.
113 pub opts: config::Options,
114 pub host_tlib_path: SearchPath,
115 /// `None` if the host and target are the same.
116 pub target_tlib_path: Option<SearchPath>,
117 pub parse_sess: ParseSess,
118 pub sysroot: PathBuf,
119 /// The name of the root source file of the crate, in the local file system.
120 /// `None` means that there is no source file.
121 pub local_crate_source_file: Option<PathBuf>,
122 /// The directory the compiler has been executed in plus a flag indicating
123 /// if the value stored here has been affected by path remapping.
124 pub working_dir: (PathBuf, bool),
126 /// Set of `(DiagnosticId, Option<Span>, message)` tuples tracking
127 /// (sub)diagnostics that have been set once, but should not be set again,
128 /// in order to avoid redundantly verbose output (Issue #24690, #44953).
129 pub one_time_diagnostics: Lock<FxHashSet<(DiagnosticMessageId, Option<Span>, String)>>,
130 crate_types: OnceCell<Vec<CrateType>>,
131 /// The `crate_disambiguator` is constructed out of all the `-C metadata`
132 /// arguments passed to the compiler. Its value together with the crate-name
133 /// forms a unique global identifier for the crate. It is used to allow
134 /// multiple crates with the same name to coexist. See the
135 /// `rustc_codegen_llvm::back::symbol_names` module for more information.
136 pub crate_disambiguator: OnceCell<CrateDisambiguator>,
138 features: OnceCell<rustc_feature::Features>,
140 lint_store: OnceCell<Lrc<dyn SessionLintStore>>,
142 /// The maximum recursion limit for potentially infinitely recursive
143 /// operations such as auto-dereference and monomorphization.
144 pub recursion_limit: OnceCell<Limit>,
146 /// The maximum length of types during monomorphization.
147 pub type_length_limit: OnceCell<Limit>,
149 /// The maximum blocks a const expression can evaluate.
150 pub const_eval_limit: OnceCell<Limit>,
152 incr_comp_session: OneThread<RefCell<IncrCompSession>>,
153 /// Used for incremental compilation tests. Will only be populated if
154 /// `-Zquery-dep-graph` is specified.
155 pub cgu_reuse_tracker: CguReuseTracker,
157 /// Used by `-Z self-profile`.
158 pub prof: SelfProfilerRef,
160 /// Some measurements that are being gathered during compilation.
161 pub perf_stats: PerfStats,
163 /// Data about code being compiled, gathered during compilation.
164 pub code_stats: CodeStats,
166 /// If `-zfuel=crate=n` is specified, `Some(crate)`.
167 optimization_fuel_crate: Option<String>,
169 /// Tracks fuel info if `-zfuel=crate=n` is specified.
170 optimization_fuel: Lock<OptimizationFuel>,
172 // The next two are public because the driver needs to read them.
173 /// If `-zprint-fuel=crate`, `Some(crate)`.
174 pub print_fuel_crate: Option<String>,
175 /// Always set to zero and incremented so that we can print fuel expended by a crate.
176 pub print_fuel: AtomicU64,
178 /// Loaded up early on in the initialization of this `Session` to avoid
179 /// false positives about a job server in our environment.
180 pub jobserver: Client,
182 /// Cap lint level specified by a driver specifically.
183 pub driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
185 /// `Span`s of trait methods that weren't found to avoid emitting object safety errors
186 pub trait_methods_not_found: Lock<FxHashSet<Span>>,
188 /// Mapping from ident span to path span for paths that don't exist as written, but that
189 /// exist under `std`. For example, wrote `str::from_utf8` instead of `std::str::from_utf8`.
190 pub confused_type_with_std_module: Lock<FxHashMap<Span, Span>>,
192 /// Path for libraries that will take preference over libraries shipped by Rust.
193 /// Used by windows-gnu targets to priortize system mingw-w64 libraries.
194 pub system_library_path: OneThread<RefCell<Option<Option<PathBuf>>>>,
196 /// Tracks the current behavior of the CTFE engine when an error occurs.
197 /// Options range from returning the error without a backtrace to returning an error
198 /// and immediately printing the backtrace to stderr.
199 pub ctfe_backtrace: Lock<CtfeBacktrace>,
201 /// This tracks where `-Zunleash-the-miri-inside-of-you` was used to get around a
202 /// const check, optionally with the relevant feature gate. We use this to
203 /// warn about unleashing, but with a single diagnostic instead of dozens that
204 /// drown everything else in noise.
205 miri_unleashed_features: Lock<Vec<(Span, Option<Symbol>)>>,
207 /// Base directory containing the `src/` for the Rust standard library, and
208 /// potentially `rustc` as well, if we can can find it. Right now it's always
209 /// `$sysroot/lib/rustlib/src/rust` (i.e. the `rustup` `rust-src` component).
211 /// This directory is what the virtual `/rustc/$hash` is translated back to,
212 /// if Rust was built with path remapping to `/rustc/$hash` enabled
213 /// (the `rust.remap-debuginfo` option in `config.toml`).
214 pub real_rust_source_base_dir: Option<PathBuf>,
216 /// Architecture to use for interpreting asm!.
217 pub asm_arch: Option<InlineAsmArch>,
219 /// Set of enabled features for the current target.
220 pub target_features: FxHashSet<Symbol>,
222 known_attrs: Lock<MarkedAttrs>,
223 used_attrs: Lock<MarkedAttrs>,
225 /// `Span`s for `if` conditions that we have suggested turning into `if let`.
226 pub if_let_suggestions: Lock<FxHashSet<Span>>,
229 pub struct PerfStats {
230 /// The accumulated time spent on computing symbol hashes.
231 pub symbol_hash_time: Lock<Duration>,
232 /// Total number of values canonicalized queries constructed.
233 pub queries_canonicalized: AtomicUsize,
234 /// Number of times this query is invoked.
235 pub normalize_generic_arg_after_erasing_regions: AtomicUsize,
236 /// Number of times this query is invoked.
237 pub normalize_projection_ty: AtomicUsize,
240 /// Enum to support dispatch of one-time diagnostics (in `Session.diag_once`).
241 enum DiagnosticBuilderMethod {
244 // Add more variants as needed to support one-time diagnostics.
247 /// Trait implemented by error types. This should not be implemented manually. Instead, use
248 /// `#[derive(SessionDiagnostic)]` -- see [rustc_macros::SessionDiagnostic].
249 pub trait SessionDiagnostic<'a> {
250 /// Write out as a diagnostic out of `sess`.
252 fn into_diagnostic(self, sess: &'a Session) -> DiagnosticBuilder<'a>;
255 /// Diagnostic message ID, used by `Session.one_time_diagnostics` to avoid
256 /// emitting the same message more than once.
257 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
258 pub enum DiagnosticMessageId {
259 ErrorId(u16), // EXXXX error code as integer
260 LintId(lint::LintId),
261 StabilityId(Option<NonZeroU32>), // issue number
264 impl From<&'static lint::Lint> for DiagnosticMessageId {
265 fn from(lint: &'static lint::Lint) -> Self {
266 DiagnosticMessageId::LintId(lint::LintId::of(lint))
271 pub fn miri_unleashed_feature(&self, span: Span, feature_gate: Option<Symbol>) {
272 self.miri_unleashed_features.lock().push((span, feature_gate));
275 fn check_miri_unleashed_features(&self) {
276 let unleashed_features = self.miri_unleashed_features.lock();
277 if !unleashed_features.is_empty() {
278 let mut must_err = false;
279 // Create a diagnostic pointing at where things got unleashed.
280 let mut diag = self.struct_warn("skipping const checks");
281 for &(span, feature_gate) in unleashed_features.iter() {
282 // FIXME: `span_label` doesn't do anything, so we use "help" as a hack.
283 if let Some(feature_gate) = feature_gate {
284 diag.span_help(span, &format!("skipping check for `{}` feature", feature_gate));
285 // The unleash flag must *not* be used to just "hack around" feature gates.
288 diag.span_help(span, "skipping check that does not even have a feature gate");
292 // If we should err, make sure we did.
293 if must_err && !self.has_errors() {
294 // We have skipped a feature gate, and not run into other errors... reject.
296 "`-Zunleash-the-miri-inside-of-you` may not be used to circumvent feature \
297 gates, except when testing error paths in the CTFE engine",
303 /// Invoked all the way at the end to finish off diagnostics printing.
304 pub fn finish_diagnostics(&self, registry: &Registry) {
305 self.check_miri_unleashed_features();
306 self.diagnostic().print_error_count(registry);
307 self.emit_future_breakage();
310 fn emit_future_breakage(&self) {
311 if !self.opts.debugging_opts.emit_future_incompat_report {
315 let diags = self.diagnostic().take_future_breakage_diagnostics();
316 if diags.is_empty() {
319 // If any future-breakage lints were registered, this lint store
320 // should be available
321 let lint_store = self.lint_store.get().expect("`lint_store` not initialized!");
322 let diags_and_breakage: Vec<(FutureBreakage, Diagnostic)> = diags
325 let lint_name = match &diag.code {
326 Some(DiagnosticId::Lint { name, has_future_breakage: true }) => name,
327 _ => panic!("Unexpected code in diagnostic {:?}", diag),
329 let lint = lint_store.name_to_lint(&lint_name);
330 let future_breakage =
331 lint.lint.future_incompatible.unwrap().future_breakage.unwrap();
332 (future_breakage, diag)
335 self.parse_sess.span_diagnostic.emit_future_breakage_report(diags_and_breakage);
338 pub fn local_crate_disambiguator(&self) -> CrateDisambiguator {
339 self.crate_disambiguator.get().copied().unwrap()
342 pub fn crate_types(&self) -> &[CrateType] {
343 self.crate_types.get().unwrap().as_slice()
346 pub fn init_crate_types(&self, crate_types: Vec<CrateType>) {
347 self.crate_types.set(crate_types).expect("`crate_types` was initialized twice")
351 pub fn recursion_limit(&self) -> Limit {
352 self.recursion_limit.get().copied().unwrap()
356 pub fn type_length_limit(&self) -> Limit {
357 self.type_length_limit.get().copied().unwrap()
360 pub fn const_eval_limit(&self) -> Limit {
361 self.const_eval_limit.get().copied().unwrap()
364 pub fn struct_span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'_> {
365 self.diagnostic().struct_span_warn(sp, msg)
367 pub fn struct_span_warn_with_code<S: Into<MultiSpan>>(
372 ) -> DiagnosticBuilder<'_> {
373 self.diagnostic().struct_span_warn_with_code(sp, msg, code)
375 pub fn struct_warn(&self, msg: &str) -> DiagnosticBuilder<'_> {
376 self.diagnostic().struct_warn(msg)
378 pub fn struct_span_allow<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'_> {
379 self.diagnostic().struct_span_allow(sp, msg)
381 pub fn struct_allow(&self, msg: &str) -> DiagnosticBuilder<'_> {
382 self.diagnostic().struct_allow(msg)
384 pub fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'_> {
385 self.diagnostic().struct_span_err(sp, msg)
387 pub fn struct_span_err_with_code<S: Into<MultiSpan>>(
392 ) -> DiagnosticBuilder<'_> {
393 self.diagnostic().struct_span_err_with_code(sp, msg, code)
395 // FIXME: This method should be removed (every error should have an associated error code).
396 pub fn struct_err(&self, msg: &str) -> DiagnosticBuilder<'_> {
397 self.diagnostic().struct_err(msg)
399 pub fn struct_err_with_code(&self, msg: &str, code: DiagnosticId) -> DiagnosticBuilder<'_> {
400 self.diagnostic().struct_err_with_code(msg, code)
402 pub fn struct_span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'_> {
403 self.diagnostic().struct_span_fatal(sp, msg)
405 pub fn struct_span_fatal_with_code<S: Into<MultiSpan>>(
410 ) -> DiagnosticBuilder<'_> {
411 self.diagnostic().struct_span_fatal_with_code(sp, msg, code)
413 pub fn struct_fatal(&self, msg: &str) -> DiagnosticBuilder<'_> {
414 self.diagnostic().struct_fatal(msg)
417 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
418 self.diagnostic().span_fatal(sp, msg).raise()
420 pub fn span_fatal_with_code<S: Into<MultiSpan>>(
426 self.diagnostic().span_fatal_with_code(sp, msg, code).raise()
428 pub fn fatal(&self, msg: &str) -> ! {
429 self.diagnostic().fatal(msg).raise()
431 pub fn span_err_or_warn<S: Into<MultiSpan>>(&self, is_warning: bool, sp: S, msg: &str) {
433 self.span_warn(sp, msg);
435 self.span_err(sp, msg);
438 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
439 self.diagnostic().span_err(sp, msg)
441 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
442 self.diagnostic().span_err_with_code(sp, &msg, code)
444 pub fn err(&self, msg: &str) {
445 self.diagnostic().err(msg)
447 pub fn emit_err<'a>(&'a self, err: impl SessionDiagnostic<'a>) {
448 err.into_diagnostic(self).emit()
450 pub fn err_count(&self) -> usize {
451 self.diagnostic().err_count()
453 pub fn has_errors(&self) -> bool {
454 self.diagnostic().has_errors()
456 pub fn has_errors_or_delayed_span_bugs(&self) -> bool {
457 self.diagnostic().has_errors_or_delayed_span_bugs()
459 pub fn abort_if_errors(&self) {
460 self.diagnostic().abort_if_errors();
462 pub fn compile_status(&self) -> Result<(), ErrorReported> {
463 if self.has_errors() {
464 self.diagnostic().emit_stashed_diagnostics();
470 // FIXME(matthewjasper) Remove this method, it should never be needed.
471 pub fn track_errors<F, T>(&self, f: F) -> Result<T, ErrorReported>
475 let old_count = self.err_count();
477 let errors = self.err_count() - old_count;
478 if errors == 0 { Ok(result) } else { Err(ErrorReported) }
480 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
481 self.diagnostic().span_warn(sp, msg)
483 pub fn span_warn_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
484 self.diagnostic().span_warn_with_code(sp, msg, code)
486 pub fn warn(&self, msg: &str) {
487 self.diagnostic().warn(msg)
489 pub fn opt_span_warn<S: Into<MultiSpan>>(&self, opt_sp: Option<S>, msg: &str) {
491 Some(sp) => self.span_warn(sp, msg),
492 None => self.warn(msg),
495 /// Delay a span_bug() call until abort_if_errors()
497 pub fn delay_span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
498 self.diagnostic().delay_span_bug(sp, msg)
501 /// Used for code paths of expensive computations that should only take place when
502 /// warnings or errors are emitted. If no messages are emitted ("good path"), then
503 /// it's likely a bug.
504 pub fn delay_good_path_bug(&self, msg: &str) {
505 if self.opts.debugging_opts.print_type_sizes
506 || self.opts.debugging_opts.query_dep_graph
507 || self.opts.debugging_opts.dump_mir.is_some()
508 || self.opts.debugging_opts.unpretty.is_some()
509 || self.opts.output_types.contains_key(&OutputType::Mir)
510 || std::env::var_os("RUSTC_LOG").is_some()
515 self.diagnostic().delay_good_path_bug(msg)
518 pub fn note_without_error(&self, msg: &str) {
519 self.diagnostic().note_without_error(msg)
521 pub fn span_note_without_error<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
522 self.diagnostic().span_note_without_error(sp, msg)
524 pub fn struct_note_without_error(&self, msg: &str) -> DiagnosticBuilder<'_> {
525 self.diagnostic().struct_note_without_error(msg)
528 pub fn diagnostic(&self) -> &rustc_errors::Handler {
529 &self.parse_sess.span_diagnostic
532 /// Analogous to calling methods on the given `DiagnosticBuilder`, but
533 /// deduplicates on lint ID, span (if any), and message for this `Session`
534 fn diag_once<'a, 'b>(
536 diag_builder: &'b mut DiagnosticBuilder<'a>,
537 method: DiagnosticBuilderMethod,
538 msg_id: DiagnosticMessageId,
540 span_maybe: Option<Span>,
542 let id_span_message = (msg_id, span_maybe, message.to_owned());
543 let fresh = self.one_time_diagnostics.borrow_mut().insert(id_span_message);
546 DiagnosticBuilderMethod::Note => {
547 diag_builder.note(message);
549 DiagnosticBuilderMethod::SpanNote => {
550 let span = span_maybe.expect("`span_note` needs a span");
551 diag_builder.span_note(span, message);
557 pub fn diag_span_note_once<'a, 'b>(
559 diag_builder: &'b mut DiagnosticBuilder<'a>,
560 msg_id: DiagnosticMessageId,
566 DiagnosticBuilderMethod::SpanNote,
573 pub fn diag_note_once<'a, 'b>(
575 diag_builder: &'b mut DiagnosticBuilder<'a>,
576 msg_id: DiagnosticMessageId,
579 self.diag_once(diag_builder, DiagnosticBuilderMethod::Note, msg_id, message, None);
583 pub fn source_map(&self) -> &SourceMap {
584 self.parse_sess.source_map()
586 pub fn verbose(&self) -> bool {
587 self.opts.debugging_opts.verbose
589 pub fn time_passes(&self) -> bool {
590 self.opts.debugging_opts.time_passes || self.opts.debugging_opts.time
592 pub fn instrument_mcount(&self) -> bool {
593 self.opts.debugging_opts.instrument_mcount
595 pub fn time_llvm_passes(&self) -> bool {
596 self.opts.debugging_opts.time_llvm_passes
598 pub fn meta_stats(&self) -> bool {
599 self.opts.debugging_opts.meta_stats
601 pub fn asm_comments(&self) -> bool {
602 self.opts.debugging_opts.asm_comments
604 pub fn verify_llvm_ir(&self) -> bool {
605 self.opts.debugging_opts.verify_llvm_ir || option_env!("RUSTC_VERIFY_LLVM_IR").is_some()
607 pub fn print_llvm_passes(&self) -> bool {
608 self.opts.debugging_opts.print_llvm_passes
610 pub fn binary_dep_depinfo(&self) -> bool {
611 self.opts.debugging_opts.binary_dep_depinfo
613 pub fn mir_opt_level(&self) -> usize {
617 .unwrap_or_else(|| if self.opts.optimize != config::OptLevel::No { 2 } else { 1 })
620 /// Gets the features enabled for the current compilation session.
621 /// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents
622 /// dependency tracking. Use tcx.features() instead.
624 pub fn features_untracked(&self) -> &rustc_feature::Features {
625 self.features.get().unwrap()
628 pub fn init_features(&self, features: rustc_feature::Features) {
629 match self.features.set(features) {
631 Err(_) => panic!("`features` was initialized twice"),
635 pub fn init_lint_store(&self, lint_store: Lrc<dyn SessionLintStore>) {
639 .expect("`lint_store` was initialized twice");
642 /// Calculates the flavor of LTO to use for this compilation.
643 pub fn lto(&self) -> config::Lto {
644 // If our target has codegen requirements ignore the command line
645 if self.target.requires_lto {
646 return config::Lto::Fat;
649 // If the user specified something, return that. If they only said `-C
650 // lto` and we've for whatever reason forced off ThinLTO via the CLI,
651 // then ensure we can't use a ThinLTO.
652 match self.opts.cg.lto {
653 config::LtoCli::Unspecified => {
654 // The compiler was invoked without the `-Clto` flag. Fall
655 // through to the default handling
657 config::LtoCli::No => {
658 // The user explicitly opted out of any kind of LTO
659 return config::Lto::No;
661 config::LtoCli::Yes | config::LtoCli::Fat | config::LtoCli::NoParam => {
662 // All of these mean fat LTO
663 return config::Lto::Fat;
665 config::LtoCli::Thin => {
666 return if self.opts.cli_forced_thinlto_off {
674 // Ok at this point the target doesn't require anything and the user
675 // hasn't asked for anything. Our next decision is whether or not
676 // we enable "auto" ThinLTO where we use multiple codegen units and
677 // then do ThinLTO over those codegen units. The logic below will
678 // either return `No` or `ThinLocal`.
680 // If processing command line options determined that we're incompatible
681 // with ThinLTO (e.g., `-C lto --emit llvm-ir`) then return that option.
682 if self.opts.cli_forced_thinlto_off {
683 return config::Lto::No;
686 // If `-Z thinlto` specified process that, but note that this is mostly
687 // a deprecated option now that `-C lto=thin` exists.
688 if let Some(enabled) = self.opts.debugging_opts.thinlto {
690 return config::Lto::ThinLocal;
692 return config::Lto::No;
696 // If there's only one codegen unit and LTO isn't enabled then there's
697 // no need for ThinLTO so just return false.
698 if self.codegen_units() == 1 {
699 return config::Lto::No;
702 // Now we're in "defaults" territory. By default we enable ThinLTO for
703 // optimized compiles (anything greater than O0).
704 match self.opts.optimize {
705 config::OptLevel::No => config::Lto::No,
706 _ => config::Lto::ThinLocal,
710 /// Returns the panic strategy for this compile session. If the user explicitly selected one
711 /// using '-C panic', use that, otherwise use the panic strategy defined by the target.
712 pub fn panic_strategy(&self) -> PanicStrategy {
713 self.opts.cg.panic.unwrap_or(self.target.panic_strategy)
715 pub fn fewer_names(&self) -> bool {
716 if let Some(fewer_names) = self.opts.debugging_opts.fewer_names {
719 let more_names = self.opts.output_types.contains_key(&OutputType::LlvmAssembly)
720 || self.opts.output_types.contains_key(&OutputType::Bitcode)
721 // AddressSanitizer and MemorySanitizer use alloca name when reporting an issue.
722 || self.opts.debugging_opts.sanitizer.intersects(SanitizerSet::ADDRESS | SanitizerSet::MEMORY);
727 pub fn unstable_options(&self) -> bool {
728 self.opts.debugging_opts.unstable_options
730 pub fn is_nightly_build(&self) -> bool {
731 self.opts.unstable_features.is_nightly_build()
733 pub fn overflow_checks(&self) -> bool {
737 .or(self.opts.debugging_opts.force_overflow_checks)
738 .unwrap_or(self.opts.debug_assertions)
741 /// Check whether this compile session and crate type use static crt.
742 pub fn crt_static(&self, crate_type: Option<CrateType>) -> bool {
743 if !self.target.crt_static_respected {
744 // If the target does not opt in to crt-static support, use its default.
745 return self.target.crt_static_default;
748 let requested_features = self.opts.cg.target_feature.split(',');
749 let found_negative = requested_features.clone().any(|r| r == "-crt-static");
750 let found_positive = requested_features.clone().any(|r| r == "+crt-static");
752 if found_positive || found_negative {
754 } else if crate_type == Some(CrateType::ProcMacro)
755 || crate_type == None && self.opts.crate_types.contains(&CrateType::ProcMacro)
757 // FIXME: When crate_type is not available,
758 // we use compiler options to determine the crate_type.
759 // We can't check `#![crate_type = "proc-macro"]` here.
762 self.target.crt_static_default
766 pub fn relocation_model(&self) -> RelocModel {
767 self.opts.cg.relocation_model.unwrap_or(self.target.relocation_model)
770 pub fn code_model(&self) -> Option<CodeModel> {
771 self.opts.cg.code_model.or(self.target.code_model)
774 pub fn tls_model(&self) -> TlsModel {
775 self.opts.debugging_opts.tls_model.unwrap_or(self.target.tls_model)
778 pub fn is_wasi_reactor(&self) -> bool {
779 self.target.options.os == "wasi"
781 self.opts.debugging_opts.wasi_exec_model,
782 Some(config::WasiExecModel::Reactor)
786 pub fn split_debuginfo(&self) -> SplitDebuginfo {
787 self.opts.cg.split_debuginfo.unwrap_or(self.target.split_debuginfo)
790 pub fn target_can_use_split_dwarf(&self) -> bool {
791 !self.target.is_like_windows && !self.target.is_like_osx
794 pub fn must_not_eliminate_frame_pointers(&self) -> bool {
795 // "mcount" function relies on stack pointer.
796 // See <https://sourceware.org/binutils/docs/gprof/Implementation.html>.
797 if self.instrument_mcount() {
799 } else if let Some(x) = self.opts.cg.force_frame_pointers {
802 !self.target.eliminate_frame_pointer
806 pub fn must_emit_unwind_tables(&self) -> bool {
807 // This is used to control the emission of the `uwtable` attribute on
810 // Unwind tables are needed when compiling with `-C panic=unwind`, but
811 // LLVM won't omit unwind tables unless the function is also marked as
812 // `nounwind`, so users are allowed to disable `uwtable` emission.
813 // Historically rustc always emits `uwtable` attributes by default, so
814 // even they can be disabled, they're still emitted by default.
816 // On some targets (including windows), however, exceptions include
817 // other events such as illegal instructions, segfaults, etc. This means
818 // that on Windows we end up still needing unwind tables even if the `-C
819 // panic=abort` flag is passed.
821 // You can also find more info on why Windows needs unwind tables in:
822 // https://bugzilla.mozilla.org/show_bug.cgi?id=1302078
824 // If a target requires unwind tables, then they must be emitted.
825 // Otherwise, we can defer to the `-C force-unwind-tables=<yes/no>`
826 // value, if it is provided, or disable them, if not.
827 self.target.requires_uwtable
828 || self.opts.cg.force_unwind_tables.unwrap_or(
829 self.panic_strategy() == PanicStrategy::Unwind || self.target.default_uwtable,
833 /// Returns the symbol name for the registrar function,
834 /// given the crate `Svh` and the function `DefIndex`.
835 pub fn generate_plugin_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String {
836 format!("__rustc_plugin_registrar_{}__", disambiguator.to_fingerprint().to_hex())
839 pub fn generate_proc_macro_decls_symbol(&self, disambiguator: CrateDisambiguator) -> String {
840 format!("__rustc_proc_macro_decls_{}__", disambiguator.to_fingerprint().to_hex())
843 pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
844 filesearch::FileSearch::new(
846 self.opts.target_triple.triple(),
847 &self.opts.search_paths,
848 // `target_tlib_path == None` means it's the same as `host_tlib_path`.
849 self.target_tlib_path.as_ref().unwrap_or(&self.host_tlib_path),
853 pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> {
854 filesearch::FileSearch::new(
856 config::host_triple(),
857 &self.opts.search_paths,
858 &self.host_tlib_path,
863 pub fn init_incr_comp_session(
865 session_dir: PathBuf,
866 lock_file: flock::Lock,
867 load_dep_graph: bool,
869 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
871 if let IncrCompSession::NotInitialized = *incr_comp_session {
873 panic!("Trying to initialize IncrCompSession `{:?}`", *incr_comp_session)
877 IncrCompSession::Active { session_directory: session_dir, lock_file, load_dep_graph };
880 pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) {
881 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
883 if let IncrCompSession::Active { .. } = *incr_comp_session {
885 panic!("trying to finalize `IncrCompSession` `{:?}`", *incr_comp_session);
888 // Note: this will also drop the lock file, thus unlocking the directory.
889 *incr_comp_session = IncrCompSession::Finalized { session_directory: new_directory_path };
892 pub fn mark_incr_comp_session_as_invalid(&self) {
893 let mut incr_comp_session = self.incr_comp_session.borrow_mut();
895 let session_directory = match *incr_comp_session {
896 IncrCompSession::Active { ref session_directory, .. } => session_directory.clone(),
897 IncrCompSession::InvalidBecauseOfErrors { .. } => return,
898 _ => panic!("trying to invalidate `IncrCompSession` `{:?}`", *incr_comp_session),
901 // Note: this will also drop the lock file, thus unlocking the directory.
902 *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors { session_directory };
905 pub fn incr_comp_session_dir(&self) -> cell::Ref<'_, PathBuf> {
906 let incr_comp_session = self.incr_comp_session.borrow();
907 cell::Ref::map(incr_comp_session, |incr_comp_session| match *incr_comp_session {
908 IncrCompSession::NotInitialized => panic!(
909 "trying to get session directory from `IncrCompSession`: {:?}",
912 IncrCompSession::Active { ref session_directory, .. }
913 | IncrCompSession::Finalized { ref session_directory }
914 | IncrCompSession::InvalidBecauseOfErrors { ref session_directory } => {
920 pub fn incr_comp_session_dir_opt(&self) -> Option<cell::Ref<'_, PathBuf>> {
921 self.opts.incremental.as_ref().map(|_| self.incr_comp_session_dir())
924 pub fn print_perf_stats(&self) {
926 "Total time spent computing symbol hashes: {}",
927 duration_to_secs_str(*self.perf_stats.symbol_hash_time.lock())
930 "Total queries canonicalized: {}",
931 self.perf_stats.queries_canonicalized.load(Ordering::Relaxed)
934 "normalize_generic_arg_after_erasing_regions: {}",
935 self.perf_stats.normalize_generic_arg_after_erasing_regions.load(Ordering::Relaxed)
938 "normalize_projection_ty: {}",
939 self.perf_stats.normalize_projection_ty.load(Ordering::Relaxed)
943 /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n.
944 /// This expends fuel if applicable, and records fuel if applicable.
945 pub fn consider_optimizing<T: Fn() -> String>(&self, crate_name: &str, msg: T) -> bool {
947 if let Some(ref c) = self.optimization_fuel_crate {
949 assert_eq!(self.threads(), 1);
950 let mut fuel = self.optimization_fuel.lock();
951 ret = fuel.remaining != 0;
952 if fuel.remaining == 0 && !fuel.out_of_fuel {
953 self.warn(&format!("optimization-fuel-exhausted: {}", msg()));
954 fuel.out_of_fuel = true;
955 } else if fuel.remaining > 0 {
960 if let Some(ref c) = self.print_fuel_crate {
962 assert_eq!(self.threads(), 1);
963 self.print_fuel.fetch_add(1, SeqCst);
969 /// Returns the number of query threads that should be used for this
971 pub fn threads(&self) -> usize {
972 self.opts.debugging_opts.threads
975 /// Returns the number of codegen units that should be used for this
977 pub fn codegen_units(&self) -> usize {
978 if let Some(n) = self.opts.cli_forced_codegen_units {
981 if let Some(n) = self.target.default_codegen_units {
985 // If incremental compilation is turned on, we default to a high number
986 // codegen units in order to reduce the "collateral damage" small
988 if self.opts.incremental.is_some() {
992 // Why is 16 codegen units the default all the time?
994 // The main reason for enabling multiple codegen units by default is to
995 // leverage the ability for the codegen backend to do codegen and
996 // optimization in parallel. This allows us, especially for large crates, to
997 // make good use of all available resources on the machine once we've
998 // hit that stage of compilation. Large crates especially then often
999 // take a long time in codegen/optimization and this helps us amortize that
1002 // Note that a high number here doesn't mean that we'll be spawning a
1003 // large number of threads in parallel. The backend of rustc contains
1004 // global rate limiting through the `jobserver` crate so we'll never
1005 // overload the system with too much work, but rather we'll only be
1006 // optimizing when we're otherwise cooperating with other instances of
1009 // Rather a high number here means that we should be able to keep a lot
1010 // of idle cpus busy. By ensuring that no codegen unit takes *too* long
1011 // to build we'll be guaranteed that all cpus will finish pretty closely
1012 // to one another and we should make relatively optimal use of system
1015 // Note that the main cost of codegen units is that it prevents LLVM
1016 // from inlining across codegen units. Users in general don't have a lot
1017 // of control over how codegen units are split up so it's our job in the
1018 // compiler to ensure that undue performance isn't lost when using
1019 // codegen units (aka we can't require everyone to slap `#[inline]` on
1022 // If we're compiling at `-O0` then the number doesn't really matter too
1023 // much because performance doesn't matter and inlining is ok to lose.
1024 // In debug mode we just want to try to guarantee that no cpu is stuck
1025 // doing work that could otherwise be farmed to others.
1027 // In release mode, however (O1 and above) performance does indeed
1028 // matter! To recover the loss in performance due to inlining we'll be
1029 // enabling ThinLTO by default (the function for which is just below).
1030 // This will ensure that we recover any inlining wins we otherwise lost
1031 // through codegen unit partitioning.
1035 // Ok that's a lot of words but the basic tl;dr; is that we want a high
1036 // number here -- but not too high. Additionally we're "safe" to have it
1037 // always at the same number at all optimization levels.
1039 // As a result 16 was chosen here! Mostly because it was a power of 2
1040 // and most benchmarks agreed it was roughly a local optimum. Not very
1045 pub fn teach(&self, code: &DiagnosticId) -> bool {
1046 self.opts.debugging_opts.teach && self.diagnostic().must_teach(code)
1049 pub fn rust_2015(&self) -> bool {
1050 self.opts.edition == Edition::Edition2015
1053 /// Are we allowed to use features from the Rust 2018 edition?
1054 pub fn rust_2018(&self) -> bool {
1055 self.opts.edition >= Edition::Edition2018
1058 /// Are we allowed to use features from the Rust 2021 edition?
1059 pub fn rust_2021(&self) -> bool {
1060 self.opts.edition >= Edition::Edition2021
1063 pub fn edition(&self) -> Edition {
1067 /// Returns `true` if we cannot skip the PLT for shared library calls.
1068 pub fn needs_plt(&self) -> bool {
1069 // Check if the current target usually needs PLT to be enabled.
1070 // The user can use the command line flag to override it.
1071 let needs_plt = self.target.needs_plt;
1073 let dbg_opts = &self.opts.debugging_opts;
1075 let relro_level = dbg_opts.relro_level.unwrap_or(self.target.relro_level);
1077 // Only enable this optimization by default if full relro is also enabled.
1078 // In this case, lazy binding was already unavailable, so nothing is lost.
1079 // This also ensures `-Wl,-z,now` is supported by the linker.
1080 let full_relro = RelroLevel::Full == relro_level;
1082 // If user didn't explicitly forced us to use / skip the PLT,
1083 // then try to skip it where possible.
1084 dbg_opts.plt.unwrap_or(needs_plt || !full_relro)
1087 /// Checks if LLVM lifetime markers should be emitted.
1088 pub fn emit_lifetime_markers(&self) -> bool {
1089 self.opts.optimize != config::OptLevel::No
1090 // AddressSanitizer uses lifetimes to detect use after scope bugs.
1091 // MemorySanitizer uses lifetimes to detect use of uninitialized stack variables.
1092 // HWAddressSanitizer will use lifetimes to detect use after scope bugs in the future.
1093 || self.opts.debugging_opts.sanitizer.intersects(SanitizerSet::ADDRESS | SanitizerSet::MEMORY | SanitizerSet::HWADDRESS)
1096 pub fn link_dead_code(&self) -> bool {
1097 self.opts.cg.link_dead_code.unwrap_or(false)
1100 pub fn instrument_coverage(&self) -> bool {
1101 self.opts.debugging_opts.instrument_coverage.unwrap_or(config::InstrumentCoverage::Off)
1102 != config::InstrumentCoverage::Off
1105 pub fn instrument_coverage_except_unused_generics(&self) -> bool {
1106 self.opts.debugging_opts.instrument_coverage.unwrap_or(config::InstrumentCoverage::Off)
1107 == config::InstrumentCoverage::ExceptUnusedGenerics
1110 pub fn instrument_coverage_except_unused_functions(&self) -> bool {
1111 self.opts.debugging_opts.instrument_coverage.unwrap_or(config::InstrumentCoverage::Off)
1112 == config::InstrumentCoverage::ExceptUnusedFunctions
1115 pub fn mark_attr_known(&self, attr: &Attribute) {
1116 self.known_attrs.lock().mark(attr)
1119 pub fn is_attr_known(&self, attr: &Attribute) -> bool {
1120 self.known_attrs.lock().is_marked(attr)
1123 pub fn mark_attr_used(&self, attr: &Attribute) {
1124 self.used_attrs.lock().mark(attr)
1127 pub fn is_attr_used(&self, attr: &Attribute) -> bool {
1128 self.used_attrs.lock().is_marked(attr)
1131 /// Returns `true` if the attribute's path matches the argument. If it
1132 /// matches, then the attribute is marked as used.
1134 /// This method should only be used by rustc, other tools can use
1135 /// `Attribute::has_name` instead, because only rustc is supposed to report
1136 /// the `unused_attributes` lint. (`MetaItem` and `NestedMetaItem` are
1137 /// produced by lowering an `Attribute` and don't have identity, so they
1138 /// only have the `has_name` method, and you need to mark the original
1139 /// `Attribute` as used when necessary.)
1140 pub fn check_name(&self, attr: &Attribute, name: Symbol) -> bool {
1141 let matches = attr.has_name(name);
1143 self.mark_attr_used(attr);
1148 pub fn is_proc_macro_attr(&self, attr: &Attribute) -> bool {
1149 [sym::proc_macro, sym::proc_macro_attribute, sym::proc_macro_derive]
1151 .any(|kind| self.check_name(attr, *kind))
1154 pub fn contains_name(&self, attrs: &[Attribute], name: Symbol) -> bool {
1155 attrs.iter().any(|item| self.check_name(item, name))
1158 pub fn find_by_name<'a>(
1160 attrs: &'a [Attribute],
1162 ) -> Option<&'a Attribute> {
1163 attrs.iter().find(|attr| self.check_name(attr, name))
1166 pub fn filter_by_name<'a>(
1168 attrs: &'a [Attribute],
1170 ) -> impl Iterator<Item = &'a Attribute> {
1171 attrs.iter().filter(move |attr| self.check_name(attr, name))
1174 pub fn first_attr_value_str_by_name(
1176 attrs: &[Attribute],
1178 ) -> Option<Symbol> {
1179 attrs.iter().find(|at| self.check_name(at, name)).and_then(|at| at.value_str())
1184 sopts: &config::Options,
1185 registry: rustc_errors::registry::Registry,
1186 source_map: Lrc<SourceMap>,
1187 emitter_dest: Option<Box<dyn Write + Send>>,
1188 ) -> Box<dyn Emitter + sync::Send> {
1189 let macro_backtrace = sopts.debugging_opts.macro_backtrace;
1190 match (sopts.error_format, emitter_dest) {
1191 (config::ErrorOutputType::HumanReadable(kind), dst) => {
1192 let (short, color_config) = kind.unzip();
1194 if let HumanReadableErrorType::AnnotateSnippet(_) = kind {
1196 AnnotateSnippetEmitterWriter::new(Some(source_map), short, macro_backtrace);
1197 Box::new(emitter.ui_testing(sopts.debugging_opts.ui_testing))
1199 let emitter = match dst {
1200 None => EmitterWriter::stderr(
1204 sopts.debugging_opts.teach,
1205 sopts.debugging_opts.terminal_width,
1208 Some(dst) => EmitterWriter::new(
1212 false, // no teach messages when writing to a buffer
1213 false, // no colors when writing to a buffer
1214 None, // no terminal width
1218 Box::new(emitter.ui_testing(sopts.debugging_opts.ui_testing))
1221 (config::ErrorOutputType::Json { pretty, json_rendered }, None) => Box::new(
1222 JsonEmitter::stderr(
1227 sopts.debugging_opts.terminal_width,
1230 .ui_testing(sopts.debugging_opts.ui_testing),
1232 (config::ErrorOutputType::Json { pretty, json_rendered }, Some(dst)) => Box::new(
1239 sopts.debugging_opts.terminal_width,
1242 .ui_testing(sopts.debugging_opts.ui_testing),
1247 pub enum DiagnosticOutput {
1249 Raw(Box<dyn Write + Send>),
1252 pub fn build_session(
1253 sopts: config::Options,
1254 local_crate_source_file: Option<PathBuf>,
1255 registry: rustc_errors::registry::Registry,
1256 diagnostics_output: DiagnosticOutput,
1257 driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
1258 file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
1259 target_override: Option<Target>,
1261 // FIXME: This is not general enough to make the warning lint completely override
1262 // normal diagnostic warnings, since the warning lint can also be denied and changed
1263 // later via the source code.
1264 let warnings_allow = sopts
1267 .filter(|&&(ref key, _)| *key == "warnings")
1268 .map(|&(_, ref level)| *level == lint::Allow)
1271 let cap_lints_allow = sopts.lint_cap.map_or(false, |cap| cap == lint::Allow);
1272 let can_emit_warnings = !(warnings_allow || cap_lints_allow);
1274 let write_dest = match diagnostics_output {
1275 DiagnosticOutput::Default => None,
1276 DiagnosticOutput::Raw(write) => Some(write),
1279 let target_cfg = config::build_target_config(&sopts, target_override);
1280 let host_triple = TargetTriple::from_triple(config::host_triple());
1281 let host = Target::search(&host_triple).unwrap_or_else(|e| {
1282 early_error(sopts.error_format, &format!("Error loading host specification: {}", e))
1285 let loader = file_loader.unwrap_or_else(|| Box::new(RealFileLoader));
1286 let hash_kind = sopts.debugging_opts.src_hash_algorithm.unwrap_or_else(|| {
1287 if target_cfg.is_like_msvc {
1288 SourceFileHashAlgorithm::Sha1
1290 SourceFileHashAlgorithm::Md5
1293 let source_map = Lrc::new(SourceMap::with_file_loader_and_hash_kind(
1295 sopts.file_path_mapping(),
1298 let emitter = default_emitter(&sopts, registry, source_map.clone(), write_dest);
1300 let span_diagnostic = rustc_errors::Handler::with_emitter_and_flags(
1302 sopts.debugging_opts.diagnostic_handler_flags(can_emit_warnings),
1305 let self_profiler = if let SwitchWithOptPath::Enabled(ref d) = sopts.debugging_opts.self_profile
1308 if let Some(ref directory) = d { directory } else { std::path::Path::new(".") };
1310 let profiler = SelfProfiler::new(
1312 sopts.crate_name.as_deref(),
1313 &sopts.debugging_opts.self_profile_events,
1316 Ok(profiler) => Some(Arc::new(profiler)),
1318 early_warn(sopts.error_format, &format!("failed to create profiler: {}", e));
1326 let mut parse_sess = ParseSess::with_span_handler(span_diagnostic, source_map);
1327 parse_sess.assume_incomplete_release = sopts.debugging_opts.assume_incomplete_release;
1328 let sysroot = match &sopts.maybe_sysroot {
1329 Some(sysroot) => sysroot.clone(),
1330 None => filesearch::get_or_default_sysroot(),
1333 let host_triple = config::host_triple();
1334 let target_triple = sopts.target_triple.triple();
1335 let host_tlib_path = SearchPath::from_sysroot_and_triple(&sysroot, host_triple);
1336 let target_tlib_path = if host_triple == target_triple {
1339 Some(SearchPath::from_sysroot_and_triple(&sysroot, target_triple))
1342 let file_path_mapping = sopts.file_path_mapping();
1344 let local_crate_source_file =
1345 local_crate_source_file.map(|path| file_path_mapping.map_prefix(path).0);
1347 let optimization_fuel_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone());
1348 let optimization_fuel = Lock::new(OptimizationFuel {
1349 remaining: sopts.debugging_opts.fuel.as_ref().map_or(0, |i| i.1),
1352 let print_fuel_crate = sopts.debugging_opts.print_fuel.clone();
1353 let print_fuel = AtomicU64::new(0);
1355 let working_dir = env::current_dir().unwrap_or_else(|e| {
1356 parse_sess.span_diagnostic.fatal(&format!("Current directory is invalid: {}", e)).raise()
1358 let working_dir = file_path_mapping.map_prefix(working_dir);
1360 let cgu_reuse_tracker = if sopts.debugging_opts.query_dep_graph {
1361 CguReuseTracker::new()
1363 CguReuseTracker::new_disabled()
1366 let prof = SelfProfilerRef::new(
1368 sopts.debugging_opts.time_passes || sopts.debugging_opts.time,
1369 sopts.debugging_opts.time_passes,
1372 let ctfe_backtrace = Lock::new(match env::var("RUSTC_CTFE_BACKTRACE") {
1373 Ok(ref val) if val == "immediate" => CtfeBacktrace::Immediate,
1374 Ok(ref val) if val != "0" => CtfeBacktrace::Capture,
1375 _ => CtfeBacktrace::Disabled,
1378 // Try to find a directory containing the Rust `src`, for more details see
1379 // the doc comment on the `real_rust_source_base_dir` field.
1380 let real_rust_source_base_dir = {
1381 // This is the location used by the `rust-src` `rustup` component.
1382 let mut candidate = sysroot.join("lib/rustlib/src/rust");
1383 if let Ok(metadata) = candidate.symlink_metadata() {
1384 // Replace the symlink rustbuild creates, with its destination.
1385 // We could try to use `fs::canonicalize` instead, but that might
1386 // produce unnecessarily verbose path.
1387 if metadata.file_type().is_symlink() {
1388 if let Ok(symlink_dest) = std::fs::read_link(&candidate) {
1389 candidate = symlink_dest;
1394 // Only use this directory if it has a file we can expect to always find.
1395 if candidate.join("library/std/src/lib.rs").is_file() { Some(candidate) } else { None }
1399 if target_cfg.allow_asm { InlineAsmArch::from_str(&target_cfg.arch).ok() } else { None };
1401 let sess = Session {
1409 local_crate_source_file,
1411 one_time_diagnostics: Default::default(),
1412 crate_types: OnceCell::new(),
1413 crate_disambiguator: OnceCell::new(),
1414 features: OnceCell::new(),
1415 lint_store: OnceCell::new(),
1416 recursion_limit: OnceCell::new(),
1417 type_length_limit: OnceCell::new(),
1418 const_eval_limit: OnceCell::new(),
1419 incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)),
1422 perf_stats: PerfStats {
1423 symbol_hash_time: Lock::new(Duration::from_secs(0)),
1424 queries_canonicalized: AtomicUsize::new(0),
1425 normalize_generic_arg_after_erasing_regions: AtomicUsize::new(0),
1426 normalize_projection_ty: AtomicUsize::new(0),
1428 code_stats: Default::default(),
1429 optimization_fuel_crate,
1433 jobserver: jobserver::client(),
1435 trait_methods_not_found: Lock::new(Default::default()),
1436 confused_type_with_std_module: Lock::new(Default::default()),
1437 system_library_path: OneThread::new(RefCell::new(Default::default())),
1439 miri_unleashed_features: Lock::new(Default::default()),
1440 real_rust_source_base_dir,
1442 target_features: FxHashSet::default(),
1443 known_attrs: Lock::new(MarkedAttrs::new()),
1444 used_attrs: Lock::new(MarkedAttrs::new()),
1445 if_let_suggestions: Default::default(),
1448 validate_commandline_args_with_session_available(&sess);
1453 // If it is useful to have a Session available already for validating a
1454 // commandline argument, you can do so here.
1455 fn validate_commandline_args_with_session_available(sess: &Session) {
1456 // Since we don't know if code in an rlib will be linked to statically or
1457 // dynamically downstream, rustc generates `__imp_` symbols that help linkers
1458 // on Windows deal with this lack of knowledge (#27438). Unfortunately,
1459 // these manually generated symbols confuse LLD when it tries to merge
1460 // bitcode during ThinLTO. Therefore we disallow dynamic linking on Windows
1461 // when compiling for LLD ThinLTO. This way we can validly just not generate
1462 // the `dllimport` attributes and `__imp_` symbols in that case.
1463 if sess.opts.cg.linker_plugin_lto.enabled()
1464 && sess.opts.cg.prefer_dynamic
1465 && sess.target.is_like_windows
1468 "Linker plugin based LTO is not supported together with \
1469 `-C prefer-dynamic` when targeting Windows-like targets",
1473 // Make sure that any given profiling data actually exists so LLVM can't
1474 // decide to silently skip PGO.
1475 if let Some(ref path) = sess.opts.cg.profile_use {
1478 "File `{}` passed to `-C profile-use` does not exist.",
1484 // Unwind tables cannot be disabled if the target requires them.
1485 if let Some(include_uwtables) = sess.opts.cg.force_unwind_tables {
1486 if sess.target.requires_uwtable && !include_uwtables {
1488 "target requires unwind tables, they cannot be disabled with \
1489 `-C force-unwind-tables=no`.",
1494 // PGO does not work reliably with panic=unwind on Windows. Let's make it
1495 // an error to combine the two for now. It always runs into an assertions
1496 // if LLVM is built with assertions, but without assertions it sometimes
1497 // does not crash and will probably generate a corrupted binary.
1498 // We should only display this error if we're actually going to run PGO.
1499 // If we're just supposed to print out some data, don't show the error (#61002).
1500 if sess.opts.cg.profile_generate.enabled()
1501 && sess.target.is_like_msvc
1502 && sess.panic_strategy() == PanicStrategy::Unwind
1503 && sess.opts.prints.iter().all(|&p| p == PrintRequest::NativeStaticLibs)
1506 "Profile-guided optimization does not yet work in conjunction \
1507 with `-Cpanic=unwind` on Windows when targeting MSVC. \
1508 See issue #61002 <https://github.com/rust-lang/rust/issues/61002> \
1509 for more information.",
1513 // Sanitizers can only be used on platforms that we know have working sanitizer codegen.
1514 let supported_sanitizers = sess.target.options.supported_sanitizers;
1515 let unsupported_sanitizers = sess.opts.debugging_opts.sanitizer - supported_sanitizers;
1516 match unsupported_sanitizers.into_iter().count() {
1519 .err(&format!("{} sanitizer is not supported for this target", unsupported_sanitizers)),
1520 _ => sess.err(&format!(
1521 "{} sanitizers are not supported for this target",
1522 unsupported_sanitizers
1525 // Cannot mix and match sanitizers.
1526 let mut sanitizer_iter = sess.opts.debugging_opts.sanitizer.into_iter();
1527 if let (Some(first), Some(second)) = (sanitizer_iter.next(), sanitizer_iter.next()) {
1528 sess.err(&format!("`-Zsanitizer={}` is incompatible with `-Zsanitizer={}`", first, second));
1532 /// Holds data on the current incremental compilation session, if there is one.
1534 pub enum IncrCompSession {
1535 /// This is the state the session will be in until the incr. comp. dir is
1538 /// This is the state during which the session directory is private and can
1540 Active { session_directory: PathBuf, lock_file: flock::Lock, load_dep_graph: bool },
1541 /// This is the state after the session directory has been finalized. In this
1542 /// state, the contents of the directory must not be modified any more.
1543 Finalized { session_directory: PathBuf },
1544 /// This is an error state that is reached when some compilation error has
1545 /// occurred. It indicates that the contents of the session directory must
1546 /// not be used, since they might be invalid.
1547 InvalidBecauseOfErrors { session_directory: PathBuf },
1550 pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! {
1551 let emitter: Box<dyn Emitter + sync::Send> = match output {
1552 config::ErrorOutputType::HumanReadable(kind) => {
1553 let (short, color_config) = kind.unzip();
1554 Box::new(EmitterWriter::stderr(color_config, None, short, false, None, false))
1556 config::ErrorOutputType::Json { pretty, json_rendered } => {
1557 Box::new(JsonEmitter::basic(pretty, json_rendered, None, false))
1560 let handler = rustc_errors::Handler::with_emitter(true, None, emitter);
1561 handler.struct_fatal(msg).emit();
1562 rustc_errors::FatalError.raise();
1565 pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
1566 let emitter: Box<dyn Emitter + sync::Send> = match output {
1567 config::ErrorOutputType::HumanReadable(kind) => {
1568 let (short, color_config) = kind.unzip();
1569 Box::new(EmitterWriter::stderr(color_config, None, short, false, None, false))
1571 config::ErrorOutputType::Json { pretty, json_rendered } => {
1572 Box::new(JsonEmitter::basic(pretty, json_rendered, None, false))
1575 let handler = rustc_errors::Handler::with_emitter(true, None, emitter);
1576 handler.struct_warn(msg).emit();