use crate::cgu_reuse_tracker::CguReuseTracker; use crate::code_stats::CodeStats; pub use crate::code_stats::{DataTypeKind, FieldInfo, SizeKind, VariantInfo}; use crate::config::{self, CrateType, OutputType, SwitchWithOptPath}; use crate::parse::ParseSess; use crate::search_paths::{PathKind, SearchPath}; use crate::{filesearch, lint}; pub use rustc_ast::attr::MarkedAttrs; pub use rustc_ast::Attribute; use rustc_data_structures::flock; use rustc_data_structures::fx::{FxHashMap, FxHashSet}; use rustc_data_structures::jobserver::{self, Client}; use rustc_data_structures::profiling::{duration_to_secs_str, SelfProfiler, SelfProfilerRef}; use rustc_data_structures::sync::{ self, AtomicU64, AtomicUsize, Lock, Lrc, OnceCell, OneThread, Ordering, Ordering::SeqCst, }; use rustc_errors::annotate_snippet_emitter_writer::AnnotateSnippetEmitterWriter; use rustc_errors::emitter::{Emitter, EmitterWriter, HumanReadableErrorType}; use rustc_errors::json::JsonEmitter; use rustc_errors::registry::Registry; use rustc_errors::{DiagnosticBuilder, DiagnosticId, ErrorReported}; use rustc_macros::HashStable_Generic; pub use rustc_span::def_id::StableCrateId; use rustc_span::edition::Edition; use rustc_span::source_map::{FileLoader, MultiSpan, RealFileLoader, SourceMap, Span}; use rustc_span::{sym, SourceFileHashAlgorithm, Symbol}; use rustc_target::asm::InlineAsmArch; use rustc_target::spec::{CodeModel, PanicStrategy, RelocModel, RelroLevel}; use rustc_target::spec::{ SanitizerSet, SplitDebuginfo, StackProtector, Target, TargetTriple, TlsModel, }; use std::cell::{self, RefCell}; use std::env; use std::fmt; use std::io::Write; use std::num::NonZeroU32; use std::ops::{Div, Mul}; use std::path::{Path, PathBuf}; use std::str::FromStr; use std::sync::Arc; use std::time::Duration; pub struct OptimizationFuel { /// If `-zfuel=crate=n` is specified, initially set to `n`, otherwise `0`. remaining: u64, /// We're rejecting all further optimizations. out_of_fuel: bool, } /// The behavior of the CTFE engine when an error occurs with regards to backtraces. #[derive(Clone, Copy)] pub enum CtfeBacktrace { /// Do nothing special, return the error as usual without a backtrace. Disabled, /// Capture a backtrace at the point the error is created and return it in the error /// (to be printed later if/when the error ever actually gets shown to the user). Capture, /// Capture a backtrace at the point the error is created and immediately print it out. Immediate, } /// New-type wrapper around `usize` for representing limits. Ensures that comparisons against /// limits are consistent throughout the compiler. #[derive(Clone, Copy, Debug, HashStable_Generic)] pub struct Limit(pub usize); impl Limit { /// Create a new limit from a `usize`. pub fn new(value: usize) -> Self { Limit(value) } /// Check that `value` is within the limit. Ensures that the same comparisons are used /// throughout the compiler, as mismatches can cause ICEs, see #72540. #[inline] pub fn value_within_limit(&self, value: usize) -> bool { value <= self.0 } } impl From for Limit { fn from(value: usize) -> Self { Self::new(value) } } impl fmt::Display for Limit { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{}", self.0) } } impl Div for Limit { type Output = Limit; fn div(self, rhs: usize) -> Self::Output { Limit::new(self.0 / rhs) } } impl Mul for Limit { type Output = Limit; fn mul(self, rhs: usize) -> Self::Output { Limit::new(self.0 * rhs) } } #[derive(Clone, Copy, Debug, HashStable_Generic)] pub struct Limits { /// The maximum recursion limit for potentially infinitely recursive /// operations such as auto-dereference and monomorphization. pub recursion_limit: Limit, /// The size at which the `large_assignments` lint starts /// being emitted. pub move_size_limit: Limit, /// The maximum length of types during monomorphization. pub type_length_limit: Limit, /// The maximum blocks a const expression can evaluate. pub const_eval_limit: Limit, } /// Represents the data associated with a compilation /// session for a single crate. pub struct Session { pub target: Target, pub host: Target, pub opts: config::Options, pub host_tlib_path: Lrc, pub target_tlib_path: Lrc, pub parse_sess: ParseSess, pub sysroot: PathBuf, /// The name of the root source file of the crate, in the local file system. /// `None` means that there is no source file. pub local_crate_source_file: Option, /// Set of `(DiagnosticId, Option, message)` tuples tracking /// (sub)diagnostics that have been set once, but should not be set again, /// in order to avoid redundantly verbose output (Issue #24690, #44953). pub one_time_diagnostics: Lock, String)>>, crate_types: OnceCell>, /// The `stable_crate_id` is constructed out of the crate name and all the /// `-C metadata` arguments passed to the compiler. Its value forms a unique /// global identifier for the crate. It is used to allow multiple crates /// with the same name to coexist. See the /// `rustc_codegen_llvm::back::symbol_names` module for more information. pub stable_crate_id: OnceCell, features: OnceCell, incr_comp_session: OneThread>, /// Used for incremental compilation tests. Will only be populated if /// `-Zquery-dep-graph` is specified. pub cgu_reuse_tracker: CguReuseTracker, /// Used by `-Z self-profile`. pub prof: SelfProfilerRef, /// Some measurements that are being gathered during compilation. pub perf_stats: PerfStats, /// Data about code being compiled, gathered during compilation. pub code_stats: CodeStats, /// Tracks fuel info if `-zfuel=crate=n` is specified. optimization_fuel: Lock, /// Always set to zero and incremented so that we can print fuel expended by a crate. pub print_fuel: AtomicU64, /// Loaded up early on in the initialization of this `Session` to avoid /// false positives about a job server in our environment. pub jobserver: Client, /// Cap lint level specified by a driver specifically. pub driver_lint_caps: FxHashMap, /// Tracks the current behavior of the CTFE engine when an error occurs. /// Options range from returning the error without a backtrace to returning an error /// and immediately printing the backtrace to stderr. /// The `Lock` is only used by miri to allow setting `ctfe_backtrace` after analysis when /// `MIRI_BACKTRACE` is set. This makes it only apply to miri's errors and not to all CTFE /// errors. pub ctfe_backtrace: Lock, /// This tracks where `-Zunleash-the-miri-inside-of-you` was used to get around a /// const check, optionally with the relevant feature gate. We use this to /// warn about unleashing, but with a single diagnostic instead of dozens that /// drown everything else in noise. miri_unleashed_features: Lock)>>, /// Architecture to use for interpreting asm!. pub asm_arch: Option, /// Set of enabled features for the current target. pub target_features: FxHashSet, } pub struct PerfStats { /// The accumulated time spent on computing symbol hashes. pub symbol_hash_time: Lock, /// Total number of values canonicalized queries constructed. pub queries_canonicalized: AtomicUsize, /// Number of times this query is invoked. pub normalize_generic_arg_after_erasing_regions: AtomicUsize, /// Number of times this query is invoked. pub normalize_projection_ty: AtomicUsize, } /// Enum to support dispatch of one-time diagnostics (in `Session.diag_once`). enum DiagnosticBuilderMethod { Note, SpanNote, // Add more variants as needed to support one-time diagnostics. } /// Trait implemented by error types. This should not be implemented manually. Instead, use /// `#[derive(SessionDiagnostic)]` -- see [rustc_macros::SessionDiagnostic]. pub trait SessionDiagnostic<'a> { /// Write out as a diagnostic out of `sess`. #[must_use] fn into_diagnostic(self, sess: &'a Session) -> DiagnosticBuilder<'a>; } /// Diagnostic message ID, used by `Session.one_time_diagnostics` to avoid /// emitting the same message more than once. #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)] pub enum DiagnosticMessageId { ErrorId(u16), // EXXXX error code as integer LintId(lint::LintId), StabilityId(Option), // issue number } impl From<&'static lint::Lint> for DiagnosticMessageId { fn from(lint: &'static lint::Lint) -> Self { DiagnosticMessageId::LintId(lint::LintId::of(lint)) } } impl Session { pub fn miri_unleashed_feature(&self, span: Span, feature_gate: Option) { self.miri_unleashed_features.lock().push((span, feature_gate)); } fn check_miri_unleashed_features(&self) { let unleashed_features = self.miri_unleashed_features.lock(); if !unleashed_features.is_empty() { let mut must_err = false; // Create a diagnostic pointing at where things got unleashed. let mut diag = self.struct_warn("skipping const checks"); for &(span, feature_gate) in unleashed_features.iter() { // FIXME: `span_label` doesn't do anything, so we use "help" as a hack. if let Some(feature_gate) = feature_gate { diag.span_help(span, &format!("skipping check for `{}` feature", feature_gate)); // The unleash flag must *not* be used to just "hack around" feature gates. must_err = true; } else { diag.span_help(span, "skipping check that does not even have a feature gate"); } } diag.emit(); // If we should err, make sure we did. if must_err && !self.has_errors() { // We have skipped a feature gate, and not run into other errors... reject. self.err( "`-Zunleash-the-miri-inside-of-you` may not be used to circumvent feature \ gates, except when testing error paths in the CTFE engine", ); } } } /// Invoked all the way at the end to finish off diagnostics printing. pub fn finish_diagnostics(&self, registry: &Registry) { self.check_miri_unleashed_features(); self.diagnostic().print_error_count(registry); self.emit_future_breakage(); } fn emit_future_breakage(&self) { if !self.opts.json_future_incompat { return; } let diags = self.diagnostic().take_future_breakage_diagnostics(); if diags.is_empty() { return; } self.parse_sess.span_diagnostic.emit_future_breakage_report(diags); } pub fn local_stable_crate_id(&self) -> StableCrateId { self.stable_crate_id.get().copied().unwrap() } pub fn crate_types(&self) -> &[CrateType] { self.crate_types.get().unwrap().as_slice() } pub fn init_crate_types(&self, crate_types: Vec) { self.crate_types.set(crate_types).expect("`crate_types` was initialized twice") } pub fn struct_span_warn>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_span_warn(sp, msg) } pub fn struct_span_force_warn>( &self, sp: S, msg: &str, ) -> DiagnosticBuilder<'_> { self.diagnostic().struct_span_force_warn(sp, msg) } pub fn struct_span_warn_with_code>( &self, sp: S, msg: &str, code: DiagnosticId, ) -> DiagnosticBuilder<'_> { self.diagnostic().struct_span_warn_with_code(sp, msg, code) } pub fn struct_warn(&self, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_warn(msg) } pub fn struct_force_warn(&self, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_force_warn(msg) } pub fn struct_span_allow>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_span_allow(sp, msg) } pub fn struct_allow(&self, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_allow(msg) } pub fn struct_span_err>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_span_err(sp, msg) } pub fn struct_span_err_with_code>( &self, sp: S, msg: &str, code: DiagnosticId, ) -> DiagnosticBuilder<'_> { self.diagnostic().struct_span_err_with_code(sp, msg, code) } // FIXME: This method should be removed (every error should have an associated error code). pub fn struct_err(&self, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_err(msg) } pub fn struct_err_with_code(&self, msg: &str, code: DiagnosticId) -> DiagnosticBuilder<'_> { self.diagnostic().struct_err_with_code(msg, code) } pub fn struct_span_fatal>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_span_fatal(sp, msg) } pub fn struct_span_fatal_with_code>( &self, sp: S, msg: &str, code: DiagnosticId, ) -> DiagnosticBuilder<'_> { self.diagnostic().struct_span_fatal_with_code(sp, msg, code) } pub fn struct_fatal(&self, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_fatal(msg) } pub fn span_fatal>(&self, sp: S, msg: &str) -> ! { self.diagnostic().span_fatal(sp, msg) } pub fn span_fatal_with_code>( &self, sp: S, msg: &str, code: DiagnosticId, ) -> ! { self.diagnostic().span_fatal_with_code(sp, msg, code) } pub fn fatal(&self, msg: &str) -> ! { self.diagnostic().fatal(msg).raise() } pub fn span_err_or_warn>(&self, is_warning: bool, sp: S, msg: &str) { if is_warning { self.span_warn(sp, msg); } else { self.span_err(sp, msg); } } pub fn span_err>(&self, sp: S, msg: &str) { self.diagnostic().span_err(sp, msg) } pub fn span_err_with_code>(&self, sp: S, msg: &str, code: DiagnosticId) { self.diagnostic().span_err_with_code(sp, &msg, code) } pub fn err(&self, msg: &str) { self.diagnostic().err(msg) } pub fn emit_err<'a>(&'a self, err: impl SessionDiagnostic<'a>) { err.into_diagnostic(self).emit() } #[inline] pub fn err_count(&self) -> usize { self.diagnostic().err_count() } pub fn has_errors(&self) -> bool { self.diagnostic().has_errors() } pub fn has_errors_or_delayed_span_bugs(&self) -> bool { self.diagnostic().has_errors_or_delayed_span_bugs() } pub fn abort_if_errors(&self) { self.diagnostic().abort_if_errors(); } pub fn compile_status(&self) -> Result<(), ErrorReported> { if self.diagnostic().has_errors_or_lint_errors() { self.diagnostic().emit_stashed_diagnostics(); Err(ErrorReported) } else { Ok(()) } } // FIXME(matthewjasper) Remove this method, it should never be needed. pub fn track_errors(&self, f: F) -> Result where F: FnOnce() -> T, { let old_count = self.err_count(); let result = f(); if self.err_count() == old_count { Ok(result) } else { Err(ErrorReported) } } pub fn span_warn>(&self, sp: S, msg: &str) { self.diagnostic().span_warn(sp, msg) } pub fn span_warn_with_code>(&self, sp: S, msg: &str, code: DiagnosticId) { self.diagnostic().span_warn_with_code(sp, msg, code) } pub fn warn(&self, msg: &str) { self.diagnostic().warn(msg) } /// Delay a span_bug() call until abort_if_errors() #[track_caller] pub fn delay_span_bug>(&self, sp: S, msg: &str) { self.diagnostic().delay_span_bug(sp, msg) } /// Used for code paths of expensive computations that should only take place when /// warnings or errors are emitted. If no messages are emitted ("good path"), then /// it's likely a bug. pub fn delay_good_path_bug(&self, msg: &str) { if self.opts.debugging_opts.print_type_sizes || self.opts.debugging_opts.query_dep_graph || self.opts.debugging_opts.dump_mir.is_some() || self.opts.debugging_opts.unpretty.is_some() || self.opts.output_types.contains_key(&OutputType::Mir) || std::env::var_os("RUSTC_LOG").is_some() { return; } self.diagnostic().delay_good_path_bug(msg) } pub fn note_without_error(&self, msg: &str) { self.diagnostic().note_without_error(msg) } pub fn span_note_without_error>(&self, sp: S, msg: &str) { self.diagnostic().span_note_without_error(sp, msg) } pub fn struct_note_without_error(&self, msg: &str) -> DiagnosticBuilder<'_> { self.diagnostic().struct_note_without_error(msg) } #[inline] pub fn diagnostic(&self) -> &rustc_errors::Handler { &self.parse_sess.span_diagnostic } pub fn with_disabled_diagnostic T>(&self, f: F) -> T { self.parse_sess.span_diagnostic.with_disabled_diagnostic(f) } /// Analogous to calling methods on the given `DiagnosticBuilder`, but /// deduplicates on lint ID, span (if any), and message for this `Session` fn diag_once<'a, 'b>( &'a self, diag_builder: &'b mut DiagnosticBuilder<'a>, method: DiagnosticBuilderMethod, msg_id: DiagnosticMessageId, message: &str, span_maybe: Option, ) { let id_span_message = (msg_id, span_maybe, message.to_owned()); let fresh = self.one_time_diagnostics.borrow_mut().insert(id_span_message); if fresh { match method { DiagnosticBuilderMethod::Note => { diag_builder.note(message); } DiagnosticBuilderMethod::SpanNote => { let span = span_maybe.expect("`span_note` needs a span"); diag_builder.span_note(span, message); } } } } pub fn diag_span_note_once<'a, 'b>( &'a self, diag_builder: &'b mut DiagnosticBuilder<'a>, msg_id: DiagnosticMessageId, span: Span, message: &str, ) { self.diag_once( diag_builder, DiagnosticBuilderMethod::SpanNote, msg_id, message, Some(span), ); } pub fn diag_note_once<'a, 'b>( &'a self, diag_builder: &'b mut DiagnosticBuilder<'a>, msg_id: DiagnosticMessageId, message: &str, ) { self.diag_once(diag_builder, DiagnosticBuilderMethod::Note, msg_id, message, None); } #[inline] pub fn source_map(&self) -> &SourceMap { self.parse_sess.source_map() } pub fn verbose(&self) -> bool { self.opts.debugging_opts.verbose } pub fn time_passes(&self) -> bool { self.opts.debugging_opts.time_passes || self.opts.debugging_opts.time } pub fn instrument_mcount(&self) -> bool { self.opts.debugging_opts.instrument_mcount } pub fn time_llvm_passes(&self) -> bool { self.opts.debugging_opts.time_llvm_passes } pub fn meta_stats(&self) -> bool { self.opts.debugging_opts.meta_stats } pub fn asm_comments(&self) -> bool { self.opts.debugging_opts.asm_comments } pub fn verify_llvm_ir(&self) -> bool { self.opts.debugging_opts.verify_llvm_ir || option_env!("RUSTC_VERIFY_LLVM_IR").is_some() } pub fn print_llvm_passes(&self) -> bool { self.opts.debugging_opts.print_llvm_passes } pub fn binary_dep_depinfo(&self) -> bool { self.opts.debugging_opts.binary_dep_depinfo } pub fn mir_opt_level(&self) -> usize { self.opts.mir_opt_level() } /// Gets the features enabled for the current compilation session. /// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents /// dependency tracking. Use tcx.features() instead. #[inline] pub fn features_untracked(&self) -> &rustc_feature::Features { self.features.get().unwrap() } pub fn init_features(&self, features: rustc_feature::Features) { match self.features.set(features) { Ok(()) => {} Err(_) => panic!("`features` was initialized twice"), } } /// Calculates the flavor of LTO to use for this compilation. pub fn lto(&self) -> config::Lto { // If our target has codegen requirements ignore the command line if self.target.requires_lto { return config::Lto::Fat; } // If the user specified something, return that. If they only said `-C // lto` and we've for whatever reason forced off ThinLTO via the CLI, // then ensure we can't use a ThinLTO. match self.opts.cg.lto { config::LtoCli::Unspecified => { // The compiler was invoked without the `-Clto` flag. Fall // through to the default handling } config::LtoCli::No => { // The user explicitly opted out of any kind of LTO return config::Lto::No; } config::LtoCli::Yes | config::LtoCli::Fat | config::LtoCli::NoParam => { // All of these mean fat LTO return config::Lto::Fat; } config::LtoCli::Thin => { return if self.opts.cli_forced_thinlto_off { config::Lto::Fat } else { config::Lto::Thin }; } } // Ok at this point the target doesn't require anything and the user // hasn't asked for anything. Our next decision is whether or not // we enable "auto" ThinLTO where we use multiple codegen units and // then do ThinLTO over those codegen units. The logic below will // either return `No` or `ThinLocal`. // If processing command line options determined that we're incompatible // with ThinLTO (e.g., `-C lto --emit llvm-ir`) then return that option. if self.opts.cli_forced_thinlto_off { return config::Lto::No; } // If `-Z thinlto` specified process that, but note that this is mostly // a deprecated option now that `-C lto=thin` exists. if let Some(enabled) = self.opts.debugging_opts.thinlto { if enabled { return config::Lto::ThinLocal; } else { return config::Lto::No; } } // If there's only one codegen unit and LTO isn't enabled then there's // no need for ThinLTO so just return false. if self.codegen_units() == 1 { return config::Lto::No; } // Now we're in "defaults" territory. By default we enable ThinLTO for // optimized compiles (anything greater than O0). match self.opts.optimize { config::OptLevel::No => config::Lto::No, _ => config::Lto::ThinLocal, } } /// Returns the panic strategy for this compile session. If the user explicitly selected one /// using '-C panic', use that, otherwise use the panic strategy defined by the target. pub fn panic_strategy(&self) -> PanicStrategy { self.opts.cg.panic.unwrap_or(self.target.panic_strategy) } pub fn fewer_names(&self) -> bool { if let Some(fewer_names) = self.opts.debugging_opts.fewer_names { fewer_names } else { let more_names = self.opts.output_types.contains_key(&OutputType::LlvmAssembly) || self.opts.output_types.contains_key(&OutputType::Bitcode) // AddressSanitizer and MemorySanitizer use alloca name when reporting an issue. || self.opts.debugging_opts.sanitizer.intersects(SanitizerSet::ADDRESS | SanitizerSet::MEMORY); !more_names } } pub fn unstable_options(&self) -> bool { self.opts.debugging_opts.unstable_options } pub fn is_nightly_build(&self) -> bool { self.opts.unstable_features.is_nightly_build() } pub fn is_sanitizer_cfi_enabled(&self) -> bool { self.opts.debugging_opts.sanitizer.contains(SanitizerSet::CFI) } pub fn overflow_checks(&self) -> bool { self.opts.cg.overflow_checks.unwrap_or(self.opts.debug_assertions) } /// Check whether this compile session and crate type use static crt. pub fn crt_static(&self, crate_type: Option) -> bool { if !self.target.crt_static_respected { // If the target does not opt in to crt-static support, use its default. return self.target.crt_static_default; } let requested_features = self.opts.cg.target_feature.split(','); let found_negative = requested_features.clone().any(|r| r == "-crt-static"); let found_positive = requested_features.clone().any(|r| r == "+crt-static"); if found_positive || found_negative { found_positive } else if crate_type == Some(CrateType::ProcMacro) || crate_type == None && self.opts.crate_types.contains(&CrateType::ProcMacro) { // FIXME: When crate_type is not available, // we use compiler options to determine the crate_type. // We can't check `#![crate_type = "proc-macro"]` here. false } else { self.target.crt_static_default } } pub fn relocation_model(&self) -> RelocModel { self.opts.cg.relocation_model.unwrap_or(self.target.relocation_model) } pub fn code_model(&self) -> Option { self.opts.cg.code_model.or(self.target.code_model) } pub fn tls_model(&self) -> TlsModel { self.opts.debugging_opts.tls_model.unwrap_or(self.target.tls_model) } pub fn is_wasi_reactor(&self) -> bool { self.target.options.os == "wasi" && matches!( self.opts.debugging_opts.wasi_exec_model, Some(config::WasiExecModel::Reactor) ) } pub fn split_debuginfo(&self) -> SplitDebuginfo { self.opts.cg.split_debuginfo.unwrap_or(self.target.split_debuginfo) } pub fn stack_protector(&self) -> StackProtector { if self.target.options.supports_stack_protector { self.opts.debugging_opts.stack_protector } else { StackProtector::None } } pub fn target_can_use_split_dwarf(&self) -> bool { !self.target.is_like_windows && !self.target.is_like_osx } pub fn must_emit_unwind_tables(&self) -> bool { // This is used to control the emission of the `uwtable` attribute on // LLVM functions. // // Unwind tables are needed when compiling with `-C panic=unwind`, but // LLVM won't omit unwind tables unless the function is also marked as // `nounwind`, so users are allowed to disable `uwtable` emission. // Historically rustc always emits `uwtable` attributes by default, so // even they can be disabled, they're still emitted by default. // // On some targets (including windows), however, exceptions include // other events such as illegal instructions, segfaults, etc. This means // that on Windows we end up still needing unwind tables even if the `-C // panic=abort` flag is passed. // // You can also find more info on why Windows needs unwind tables in: // https://bugzilla.mozilla.org/show_bug.cgi?id=1302078 // // If a target requires unwind tables, then they must be emitted. // Otherwise, we can defer to the `-C force-unwind-tables=` // value, if it is provided, or disable them, if not. self.target.requires_uwtable || self.opts.cg.force_unwind_tables.unwrap_or( self.panic_strategy() == PanicStrategy::Unwind || self.target.default_uwtable, ) } pub fn generate_proc_macro_decls_symbol(&self, stable_crate_id: StableCrateId) -> String { format!("__rustc_proc_macro_decls_{:08x}__", stable_crate_id.to_u64()) } pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> { filesearch::FileSearch::new( &self.sysroot, self.opts.target_triple.triple(), &self.opts.search_paths, &self.target_tlib_path, kind, ) } pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch<'_> { filesearch::FileSearch::new( &self.sysroot, config::host_triple(), &self.opts.search_paths, &self.host_tlib_path, kind, ) } /// Returns a list of directories where target-specific tool binaries are located. pub fn get_tools_search_paths(&self, self_contained: bool) -> Vec { let rustlib_path = rustc_target::target_rustlib_path(&self.sysroot, &config::host_triple()); let p = PathBuf::from_iter([ Path::new(&self.sysroot), Path::new(&rustlib_path), Path::new("bin"), ]); if self_contained { vec![p.clone(), p.join("self-contained")] } else { vec![p] } } pub fn init_incr_comp_session( &self, session_dir: PathBuf, lock_file: flock::Lock, load_dep_graph: bool, ) { let mut incr_comp_session = self.incr_comp_session.borrow_mut(); if let IncrCompSession::NotInitialized = *incr_comp_session { } else { panic!("Trying to initialize IncrCompSession `{:?}`", *incr_comp_session) } *incr_comp_session = IncrCompSession::Active { session_directory: session_dir, lock_file, load_dep_graph }; } pub fn finalize_incr_comp_session(&self, new_directory_path: PathBuf) { let mut incr_comp_session = self.incr_comp_session.borrow_mut(); if let IncrCompSession::Active { .. } = *incr_comp_session { } else { panic!("trying to finalize `IncrCompSession` `{:?}`", *incr_comp_session); } // Note: this will also drop the lock file, thus unlocking the directory. *incr_comp_session = IncrCompSession::Finalized { session_directory: new_directory_path }; } pub fn mark_incr_comp_session_as_invalid(&self) { let mut incr_comp_session = self.incr_comp_session.borrow_mut(); let session_directory = match *incr_comp_session { IncrCompSession::Active { ref session_directory, .. } => session_directory.clone(), IncrCompSession::InvalidBecauseOfErrors { .. } => return, _ => panic!("trying to invalidate `IncrCompSession` `{:?}`", *incr_comp_session), }; // Note: this will also drop the lock file, thus unlocking the directory. *incr_comp_session = IncrCompSession::InvalidBecauseOfErrors { session_directory }; } pub fn incr_comp_session_dir(&self) -> cell::Ref<'_, PathBuf> { let incr_comp_session = self.incr_comp_session.borrow(); cell::Ref::map(incr_comp_session, |incr_comp_session| match *incr_comp_session { IncrCompSession::NotInitialized => panic!( "trying to get session directory from `IncrCompSession`: {:?}", *incr_comp_session, ), IncrCompSession::Active { ref session_directory, .. } | IncrCompSession::Finalized { ref session_directory } | IncrCompSession::InvalidBecauseOfErrors { ref session_directory } => { session_directory } }) } pub fn incr_comp_session_dir_opt(&self) -> Option> { self.opts.incremental.as_ref().map(|_| self.incr_comp_session_dir()) } pub fn print_perf_stats(&self) { eprintln!( "Total time spent computing symbol hashes: {}", duration_to_secs_str(*self.perf_stats.symbol_hash_time.lock()) ); eprintln!( "Total queries canonicalized: {}", self.perf_stats.queries_canonicalized.load(Ordering::Relaxed) ); eprintln!( "normalize_generic_arg_after_erasing_regions: {}", self.perf_stats.normalize_generic_arg_after_erasing_regions.load(Ordering::Relaxed) ); eprintln!( "normalize_projection_ty: {}", self.perf_stats.normalize_projection_ty.load(Ordering::Relaxed) ); } /// We want to know if we're allowed to do an optimization for crate foo from -z fuel=foo=n. /// This expends fuel if applicable, and records fuel if applicable. pub fn consider_optimizing String>(&self, crate_name: &str, msg: T) -> bool { let mut ret = true; if let Some((ref c, _)) = self.opts.debugging_opts.fuel { if c == crate_name { assert_eq!(self.threads(), 1); let mut fuel = self.optimization_fuel.lock(); ret = fuel.remaining != 0; if fuel.remaining == 0 && !fuel.out_of_fuel { if self.diagnostic().can_emit_warnings() { // We only call `msg` in case we can actually emit warnings. // Otherwise, this could cause a `delay_good_path_bug` to // trigger (issue #79546). self.warn(&format!("optimization-fuel-exhausted: {}", msg())); } fuel.out_of_fuel = true; } else if fuel.remaining > 0 { fuel.remaining -= 1; } } } if let Some(ref c) = self.opts.debugging_opts.print_fuel { if c == crate_name { assert_eq!(self.threads(), 1); self.print_fuel.fetch_add(1, SeqCst); } } ret } /// Returns the number of query threads that should be used for this /// compilation pub fn threads(&self) -> usize { self.opts.debugging_opts.threads } /// Returns the number of codegen units that should be used for this /// compilation pub fn codegen_units(&self) -> usize { if let Some(n) = self.opts.cli_forced_codegen_units { return n; } if let Some(n) = self.target.default_codegen_units { return n as usize; } // If incremental compilation is turned on, we default to a high number // codegen units in order to reduce the "collateral damage" small // changes cause. if self.opts.incremental.is_some() { return 256; } // Why is 16 codegen units the default all the time? // // The main reason for enabling multiple codegen units by default is to // leverage the ability for the codegen backend to do codegen and // optimization in parallel. This allows us, especially for large crates, to // make good use of all available resources on the machine once we've // hit that stage of compilation. Large crates especially then often // take a long time in codegen/optimization and this helps us amortize that // cost. // // Note that a high number here doesn't mean that we'll be spawning a // large number of threads in parallel. The backend of rustc contains // global rate limiting through the `jobserver` crate so we'll never // overload the system with too much work, but rather we'll only be // optimizing when we're otherwise cooperating with other instances of // rustc. // // Rather a high number here means that we should be able to keep a lot // of idle cpus busy. By ensuring that no codegen unit takes *too* long // to build we'll be guaranteed that all cpus will finish pretty closely // to one another and we should make relatively optimal use of system // resources // // Note that the main cost of codegen units is that it prevents LLVM // from inlining across codegen units. Users in general don't have a lot // of control over how codegen units are split up so it's our job in the // compiler to ensure that undue performance isn't lost when using // codegen units (aka we can't require everyone to slap `#[inline]` on // everything). // // If we're compiling at `-O0` then the number doesn't really matter too // much because performance doesn't matter and inlining is ok to lose. // In debug mode we just want to try to guarantee that no cpu is stuck // doing work that could otherwise be farmed to others. // // In release mode, however (O1 and above) performance does indeed // matter! To recover the loss in performance due to inlining we'll be // enabling ThinLTO by default (the function for which is just below). // This will ensure that we recover any inlining wins we otherwise lost // through codegen unit partitioning. // // --- // // Ok that's a lot of words but the basic tl;dr; is that we want a high // number here -- but not too high. Additionally we're "safe" to have it // always at the same number at all optimization levels. // // As a result 16 was chosen here! Mostly because it was a power of 2 // and most benchmarks agreed it was roughly a local optimum. Not very // scientific. 16 } pub fn teach(&self, code: &DiagnosticId) -> bool { self.opts.debugging_opts.teach && self.diagnostic().must_teach(code) } pub fn rust_2015(&self) -> bool { self.opts.edition == Edition::Edition2015 } /// Are we allowed to use features from the Rust 2018 edition? pub fn rust_2018(&self) -> bool { self.opts.edition >= Edition::Edition2018 } /// Are we allowed to use features from the Rust 2021 edition? pub fn rust_2021(&self) -> bool { self.opts.edition >= Edition::Edition2021 } pub fn edition(&self) -> Edition { self.opts.edition } /// Returns `true` if we cannot skip the PLT for shared library calls. pub fn needs_plt(&self) -> bool { // Check if the current target usually needs PLT to be enabled. // The user can use the command line flag to override it. let needs_plt = self.target.needs_plt; let dbg_opts = &self.opts.debugging_opts; let relro_level = dbg_opts.relro_level.unwrap_or(self.target.relro_level); // Only enable this optimization by default if full relro is also enabled. // In this case, lazy binding was already unavailable, so nothing is lost. // This also ensures `-Wl,-z,now` is supported by the linker. let full_relro = RelroLevel::Full == relro_level; // If user didn't explicitly forced us to use / skip the PLT, // then try to skip it where possible. dbg_opts.plt.unwrap_or(needs_plt || !full_relro) } /// Checks if LLVM lifetime markers should be emitted. pub fn emit_lifetime_markers(&self) -> bool { self.opts.optimize != config::OptLevel::No // AddressSanitizer uses lifetimes to detect use after scope bugs. // MemorySanitizer uses lifetimes to detect use of uninitialized stack variables. // HWAddressSanitizer will use lifetimes to detect use after scope bugs in the future. || self.opts.debugging_opts.sanitizer.intersects(SanitizerSet::ADDRESS | SanitizerSet::MEMORY | SanitizerSet::HWADDRESS) } pub fn link_dead_code(&self) -> bool { self.opts.cg.link_dead_code.unwrap_or(false) } pub fn instrument_coverage(&self) -> bool { self.opts.instrument_coverage() } pub fn instrument_coverage_except_unused_generics(&self) -> bool { self.opts.instrument_coverage_except_unused_generics() } pub fn instrument_coverage_except_unused_functions(&self) -> bool { self.opts.instrument_coverage_except_unused_functions() } pub fn is_proc_macro_attr(&self, attr: &Attribute) -> bool { [sym::proc_macro, sym::proc_macro_attribute, sym::proc_macro_derive] .iter() .any(|kind| attr.has_name(*kind)) } pub fn contains_name(&self, attrs: &[Attribute], name: Symbol) -> bool { attrs.iter().any(|item| item.has_name(name)) } pub fn find_by_name<'a>( &'a self, attrs: &'a [Attribute], name: Symbol, ) -> Option<&'a Attribute> { attrs.iter().find(|attr| attr.has_name(name)) } pub fn filter_by_name<'a>( &'a self, attrs: &'a [Attribute], name: Symbol, ) -> impl Iterator { attrs.iter().filter(move |attr| attr.has_name(name)) } pub fn first_attr_value_str_by_name( &self, attrs: &[Attribute], name: Symbol, ) -> Option { attrs.iter().find(|at| at.has_name(name)).and_then(|at| at.value_str()) } } fn default_emitter( sopts: &config::Options, registry: rustc_errors::registry::Registry, source_map: Lrc, emitter_dest: Option>, ) -> Box { let macro_backtrace = sopts.debugging_opts.macro_backtrace; match (sopts.error_format, emitter_dest) { (config::ErrorOutputType::HumanReadable(kind), dst) => { let (short, color_config) = kind.unzip(); if let HumanReadableErrorType::AnnotateSnippet(_) = kind { let emitter = AnnotateSnippetEmitterWriter::new(Some(source_map), short, macro_backtrace); Box::new(emitter.ui_testing(sopts.debugging_opts.ui_testing)) } else { let emitter = match dst { None => EmitterWriter::stderr( color_config, Some(source_map), short, sopts.debugging_opts.teach, sopts.debugging_opts.terminal_width, macro_backtrace, ), Some(dst) => EmitterWriter::new( dst, Some(source_map), short, false, // no teach messages when writing to a buffer false, // no colors when writing to a buffer None, // no terminal width macro_backtrace, ), }; Box::new(emitter.ui_testing(sopts.debugging_opts.ui_testing)) } } (config::ErrorOutputType::Json { pretty, json_rendered }, None) => Box::new( JsonEmitter::stderr( Some(registry), source_map, pretty, json_rendered, sopts.debugging_opts.terminal_width, macro_backtrace, ) .ui_testing(sopts.debugging_opts.ui_testing), ), (config::ErrorOutputType::Json { pretty, json_rendered }, Some(dst)) => Box::new( JsonEmitter::new( dst, Some(registry), source_map, pretty, json_rendered, sopts.debugging_opts.terminal_width, macro_backtrace, ) .ui_testing(sopts.debugging_opts.ui_testing), ), } } pub enum DiagnosticOutput { Default, Raw(Box), } pub fn build_session( sopts: config::Options, local_crate_source_file: Option, registry: rustc_errors::registry::Registry, diagnostics_output: DiagnosticOutput, driver_lint_caps: FxHashMap, file_loader: Option>, target_override: Option, ) -> Session { // FIXME: This is not general enough to make the warning lint completely override // normal diagnostic warnings, since the warning lint can also be denied and changed // later via the source code. let warnings_allow = sopts .lint_opts .iter() .filter(|&&(ref key, _)| *key == "warnings") .map(|&(_, ref level)| *level == lint::Allow) .last() .unwrap_or(false); let cap_lints_allow = sopts.lint_cap.map_or(false, |cap| cap == lint::Allow); let can_emit_warnings = !(warnings_allow || cap_lints_allow); let write_dest = match diagnostics_output { DiagnosticOutput::Default => None, DiagnosticOutput::Raw(write) => Some(write), }; let sysroot = match &sopts.maybe_sysroot { Some(sysroot) => sysroot.clone(), None => filesearch::get_or_default_sysroot(), }; let target_cfg = config::build_target_config(&sopts, target_override, &sysroot); let host_triple = TargetTriple::from_triple(config::host_triple()); let (host, target_warnings) = Target::search(&host_triple, &sysroot).unwrap_or_else(|e| { early_error(sopts.error_format, &format!("Error loading host specification: {}", e)) }); for warning in target_warnings.warning_messages() { early_warn(sopts.error_format, &warning) } let loader = file_loader.unwrap_or_else(|| Box::new(RealFileLoader)); let hash_kind = sopts.debugging_opts.src_hash_algorithm.unwrap_or_else(|| { if target_cfg.is_like_msvc { SourceFileHashAlgorithm::Sha1 } else { SourceFileHashAlgorithm::Md5 } }); let source_map = Lrc::new(SourceMap::with_file_loader_and_hash_kind( loader, sopts.file_path_mapping(), hash_kind, )); let emitter = default_emitter(&sopts, registry, source_map.clone(), write_dest); let span_diagnostic = rustc_errors::Handler::with_emitter_and_flags( emitter, sopts.debugging_opts.diagnostic_handler_flags(can_emit_warnings), ); let self_profiler = if let SwitchWithOptPath::Enabled(ref d) = sopts.debugging_opts.self_profile { let directory = if let Some(ref directory) = d { directory } else { std::path::Path::new(".") }; let profiler = SelfProfiler::new( directory, sopts.crate_name.as_deref(), &sopts.debugging_opts.self_profile_events, ); match profiler { Ok(profiler) => Some(Arc::new(profiler)), Err(e) => { early_warn(sopts.error_format, &format!("failed to create profiler: {}", e)); None } } } else { None }; let mut parse_sess = ParseSess::with_span_handler(span_diagnostic, source_map); parse_sess.assume_incomplete_release = sopts.debugging_opts.assume_incomplete_release; let host_triple = config::host_triple(); let target_triple = sopts.target_triple.triple(); let host_tlib_path = Lrc::new(SearchPath::from_sysroot_and_triple(&sysroot, host_triple)); let target_tlib_path = if host_triple == target_triple { // Use the same `SearchPath` if host and target triple are identical to avoid unnecessary // rescanning of the target lib path and an unnecessary allocation. host_tlib_path.clone() } else { Lrc::new(SearchPath::from_sysroot_and_triple(&sysroot, target_triple)) }; let file_path_mapping = sopts.file_path_mapping(); let local_crate_source_file = local_crate_source_file.map(|path| file_path_mapping.map_prefix(path).0); let optimization_fuel = Lock::new(OptimizationFuel { remaining: sopts.debugging_opts.fuel.as_ref().map_or(0, |i| i.1), out_of_fuel: false, }); let print_fuel = AtomicU64::new(0); let cgu_reuse_tracker = if sopts.debugging_opts.query_dep_graph { CguReuseTracker::new() } else { CguReuseTracker::new_disabled() }; let prof = SelfProfilerRef::new( self_profiler, sopts.debugging_opts.time_passes || sopts.debugging_opts.time, sopts.debugging_opts.time_passes, ); let ctfe_backtrace = Lock::new(match env::var("RUSTC_CTFE_BACKTRACE") { Ok(ref val) if val == "immediate" => CtfeBacktrace::Immediate, Ok(ref val) if val != "0" => CtfeBacktrace::Capture, _ => CtfeBacktrace::Disabled, }); let asm_arch = if target_cfg.allow_asm { InlineAsmArch::from_str(&target_cfg.arch).ok() } else { None }; let sess = Session { target: target_cfg, host, opts: sopts, host_tlib_path, target_tlib_path, parse_sess, sysroot, local_crate_source_file, one_time_diagnostics: Default::default(), crate_types: OnceCell::new(), stable_crate_id: OnceCell::new(), features: OnceCell::new(), incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)), cgu_reuse_tracker, prof, perf_stats: PerfStats { symbol_hash_time: Lock::new(Duration::from_secs(0)), queries_canonicalized: AtomicUsize::new(0), normalize_generic_arg_after_erasing_regions: AtomicUsize::new(0), normalize_projection_ty: AtomicUsize::new(0), }, code_stats: Default::default(), optimization_fuel, print_fuel, jobserver: jobserver::client(), driver_lint_caps, ctfe_backtrace, miri_unleashed_features: Lock::new(Default::default()), asm_arch, target_features: FxHashSet::default(), }; validate_commandline_args_with_session_available(&sess); sess } // If it is useful to have a Session available already for validating a // commandline argument, you can do so here. fn validate_commandline_args_with_session_available(sess: &Session) { // Since we don't know if code in an rlib will be linked to statically or // dynamically downstream, rustc generates `__imp_` symbols that help linkers // on Windows deal with this lack of knowledge (#27438). Unfortunately, // these manually generated symbols confuse LLD when it tries to merge // bitcode during ThinLTO. Therefore we disallow dynamic linking on Windows // when compiling for LLD ThinLTO. This way we can validly just not generate // the `dllimport` attributes and `__imp_` symbols in that case. if sess.opts.cg.linker_plugin_lto.enabled() && sess.opts.cg.prefer_dynamic && sess.target.is_like_windows { sess.err( "Linker plugin based LTO is not supported together with \ `-C prefer-dynamic` when targeting Windows-like targets", ); } // Make sure that any given profiling data actually exists so LLVM can't // decide to silently skip PGO. if let Some(ref path) = sess.opts.cg.profile_use { if !path.exists() { sess.err(&format!( "File `{}` passed to `-C profile-use` does not exist.", path.display() )); } } // Do the same for sample profile data. if let Some(ref path) = sess.opts.debugging_opts.profile_sample_use { if !path.exists() { sess.err(&format!( "File `{}` passed to `-C profile-sample-use` does not exist.", path.display() )); } } // Unwind tables cannot be disabled if the target requires them. if let Some(include_uwtables) = sess.opts.cg.force_unwind_tables { if sess.target.requires_uwtable && !include_uwtables { sess.err( "target requires unwind tables, they cannot be disabled with \ `-C force-unwind-tables=no`.", ); } } // Sanitizers can only be used on platforms that we know have working sanitizer codegen. let supported_sanitizers = sess.target.options.supported_sanitizers; let unsupported_sanitizers = sess.opts.debugging_opts.sanitizer - supported_sanitizers; match unsupported_sanitizers.into_iter().count() { 0 => {} 1 => sess .err(&format!("{} sanitizer is not supported for this target", unsupported_sanitizers)), _ => sess.err(&format!( "{} sanitizers are not supported for this target", unsupported_sanitizers )), } // Cannot mix and match sanitizers. let mut sanitizer_iter = sess.opts.debugging_opts.sanitizer.into_iter(); if let (Some(first), Some(second)) = (sanitizer_iter.next(), sanitizer_iter.next()) { sess.err(&format!("`-Zsanitizer={}` is incompatible with `-Zsanitizer={}`", first, second)); } // Cannot enable crt-static with sanitizers on Linux if sess.crt_static(None) && !sess.opts.debugging_opts.sanitizer.is_empty() { sess.err( "sanitizer is incompatible with statically linked libc, \ disable it using `-C target-feature=-crt-static`", ); } // LLVM CFI requires LTO. if sess.is_sanitizer_cfi_enabled() { if sess.opts.cg.lto == config::LtoCli::Unspecified || sess.opts.cg.lto == config::LtoCli::No || sess.opts.cg.lto == config::LtoCli::Thin { sess.err("`-Zsanitizer=cfi` requires `-Clto`"); } } if sess.opts.debugging_opts.stack_protector != StackProtector::None { if !sess.target.options.supports_stack_protector { sess.warn(&format!( "`-Z stack-protector={}` is not supported for target {} and will be ignored", sess.opts.debugging_opts.stack_protector, sess.opts.target_triple )) } } } /// Holds data on the current incremental compilation session, if there is one. #[derive(Debug)] pub enum IncrCompSession { /// This is the state the session will be in until the incr. comp. dir is /// needed. NotInitialized, /// This is the state during which the session directory is private and can /// be modified. Active { session_directory: PathBuf, lock_file: flock::Lock, load_dep_graph: bool }, /// This is the state after the session directory has been finalized. In this /// state, the contents of the directory must not be modified any more. Finalized { session_directory: PathBuf }, /// This is an error state that is reached when some compilation error has /// occurred. It indicates that the contents of the session directory must /// not be used, since they might be invalid. InvalidBecauseOfErrors { session_directory: PathBuf }, } pub fn early_error_no_abort(output: config::ErrorOutputType, msg: &str) { let emitter: Box = match output { config::ErrorOutputType::HumanReadable(kind) => { let (short, color_config) = kind.unzip(); Box::new(EmitterWriter::stderr(color_config, None, short, false, None, false)) } config::ErrorOutputType::Json { pretty, json_rendered } => { Box::new(JsonEmitter::basic(pretty, json_rendered, None, false)) } }; let handler = rustc_errors::Handler::with_emitter(true, None, emitter); handler.struct_fatal(msg).emit(); } pub fn early_error(output: config::ErrorOutputType, msg: &str) -> ! { early_error_no_abort(output, msg); rustc_errors::FatalError.raise(); } pub fn early_warn(output: config::ErrorOutputType, msg: &str) { let emitter: Box = match output { config::ErrorOutputType::HumanReadable(kind) => { let (short, color_config) = kind.unzip(); Box::new(EmitterWriter::stderr(color_config, None, short, false, None, false)) } config::ErrorOutputType::Json { pretty, json_rendered } => { Box::new(JsonEmitter::basic(pretty, json_rendered, None, false)) } }; let handler = rustc_errors::Handler::with_emitter(true, None, emitter); handler.struct_warn(msg).emit(); }