// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. pub use self::code_stats::{CodeStats, DataTypeKind, FieldInfo}; pub use self::code_stats::{SizeKind, TypeSizeInfo, VariantInfo}; use hir::def_id::CrateNum; use ich::Fingerprint; use ich; use lint; use lint::builtin::BuiltinLintDiagnostics; use middle::allocator::AllocatorKind; use middle::dependency_format; use session::search_paths::PathKind; use session::config::{OutputType}; use ty::tls; use util::nodemap::{FxHashSet}; use util::common::{duration_to_secs_str, ErrorReported}; use util::common::ProfileQueriesMsg; use rustc_data_structures::sync::{self, Lrc, Lock, LockCell, OneThread, Once, RwLock}; use syntax::ast::NodeId; use errors::{self, DiagnosticBuilder, DiagnosticId}; use errors::emitter::{Emitter, EmitterWriter}; use syntax::edition::Edition; use syntax::json::JsonEmitter; use syntax::feature_gate; use syntax::symbol::Symbol; use syntax::parse; use syntax::parse::ParseSess; use syntax::{ast, codemap}; use syntax::feature_gate::AttributeType; use syntax_pos::{MultiSpan, Span}; use rustc_target::spec::{LinkerFlavor, PanicStrategy}; use rustc_target::spec::{Target, TargetTriple}; use rustc_data_structures::flock; use jobserver::Client; use std; use std::cell::{self, Cell, RefCell}; use std::collections::HashMap; use std::env; use std::fmt; use std::io::Write; use std::path::{Path, PathBuf}; use std::time::Duration; use std::sync::mpsc; use std::sync::atomic::{AtomicUsize, Ordering}; mod code_stats; pub mod config; pub mod filesearch; pub mod search_paths; /// Represents the data associated with a compilation /// session for a single crate. pub struct Session { pub target: config::Config, pub host: Target, pub opts: config::Options, pub parse_sess: ParseSess, /// For a library crate, this is always none pub entry_fn: Once>, pub plugin_registrar_fn: Once>, pub derive_registrar_fn: Once>, pub default_sysroot: Option, /// 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, /// The directory the compiler has been executed in plus a flag indicating /// if the value stored here has been affected by path remapping. pub working_dir: (PathBuf, bool), // FIXME: lint_store and buffered_lints are not thread-safe, // but are only used in a single thread pub lint_store: RwLock, pub buffered_lints: Lock>, /// 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)>>, pub plugin_llvm_passes: OneThread>>, pub plugin_attributes: OneThread>>, pub crate_types: Once>, pub dependency_formats: Once, /// The crate_disambiguator is constructed out of all the `-C metadata` /// arguments passed to the compiler. Its value together with the crate-name /// 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 crate_disambiguator: Once, features: Once, /// The maximum recursion limit for potentially infinitely recursive /// operations such as auto-dereference and monomorphization. pub recursion_limit: Once, /// The maximum length of types during monomorphization. pub type_length_limit: Once, /// The maximum number of stackframes allowed in const eval pub const_eval_stack_frame_limit: usize, /// The metadata::creader module may inject an allocator/panic_runtime /// dependency if it didn't already find one, and this tracks what was /// injected. pub injected_allocator: Once>, pub allocator_kind: Once>, pub injected_panic_runtime: Once>, /// Map from imported macro spans (which consist of /// the localized span for the macro body) to the /// macro name and definition span in the source crate. pub imported_macro_spans: OneThread>>, incr_comp_session: OneThread>, /// A cache of attributes ignored by StableHashingContext pub ignored_attr_names: FxHashSet, /// Used by -Z profile-queries in util::common pub profile_channel: Lock>>, /// Some measurements that are being gathered during compilation. pub perf_stats: PerfStats, /// Data about code being compiled, gathered during compilation. pub code_stats: Lock, next_node_id: OneThread>, /// If -zfuel=crate=n is specified, Some(crate). optimization_fuel_crate: Option, /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0. optimization_fuel_limit: LockCell, /// We're rejecting all further optimizations. out_of_fuel: LockCell, // The next two are public because the driver needs to read them. /// If -zprint-fuel=crate, Some(crate). pub print_fuel_crate: Option, /// Always set to zero and incremented so that we can print fuel expended by a crate. pub print_fuel: LockCell, /// Loaded up early on in the initialization of this `Session` to avoid /// false positives about a job server in our environment. pub jobserver: Client, /// Metadata about the allocators for the current crate being compiled pub has_global_allocator: Once, } pub struct PerfStats { /// The accumulated time spent on computing symbol hashes pub symbol_hash_time: Lock, /// The accumulated time spent decoding def path tables from metadata pub decode_def_path_tables_time: Lock, /// Total number of values canonicalized queries constructed. pub queries_canonicalized: AtomicUsize, /// Number of times this query is invoked. pub normalize_ty_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, SpanSuggestion(String), // suggestion // add more variants as needed to support one-time diagnostics } /// 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(u32), // 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 local_crate_disambiguator(&self) -> CrateDisambiguator { *self.crate_disambiguator.get() } pub fn struct_span_warn<'a, S: Into>( &'a self, sp: S, msg: &str, ) -> DiagnosticBuilder<'a> { self.diagnostic().struct_span_warn(sp, msg) } pub fn struct_span_warn_with_code<'a, S: Into>( &'a self, sp: S, msg: &str, code: DiagnosticId, ) -> DiagnosticBuilder<'a> { self.diagnostic().struct_span_warn_with_code(sp, msg, code) } pub fn struct_warn<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> { self.diagnostic().struct_warn(msg) } pub fn struct_span_err<'a, S: Into>( &'a self, sp: S, msg: &str, ) -> DiagnosticBuilder<'a> { self.diagnostic().struct_span_err(sp, msg) } pub fn struct_span_err_with_code<'a, S: Into>( &'a self, sp: S, msg: &str, code: DiagnosticId, ) -> DiagnosticBuilder<'a> { 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<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> { self.diagnostic().struct_err(msg) } pub fn struct_err_with_code<'a>( &'a self, msg: &str, code: DiagnosticId, ) -> DiagnosticBuilder<'a> { self.diagnostic().struct_err_with_code(msg, code) } pub fn struct_span_fatal<'a, S: Into>( &'a self, sp: S, msg: &str, ) -> DiagnosticBuilder<'a> { self.diagnostic().struct_span_fatal(sp, msg) } pub fn struct_span_fatal_with_code<'a, S: Into>( &'a self, sp: S, msg: &str, code: DiagnosticId, ) -> DiagnosticBuilder<'a> { self.diagnostic().struct_span_fatal_with_code(sp, msg, code) } pub fn struct_fatal<'a>(&'a self, msg: &str) -> DiagnosticBuilder<'a> { self.diagnostic().struct_fatal(msg) } pub fn span_fatal>(&self, sp: S, msg: &str) -> ! { self.diagnostic().span_fatal(sp, msg).raise() } pub fn span_fatal_with_code>( &self, sp: S, msg: &str, code: DiagnosticId, ) -> ! { self.diagnostic() .span_fatal_with_code(sp, msg, code) .raise() } 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 err_count(&self) -> usize { self.diagnostic().err_count() } pub fn has_errors(&self) -> bool { self.diagnostic().has_errors() } pub fn abort_if_errors(&self) { self.diagnostic().abort_if_errors(); } pub fn compile_status(&self) -> Result<(), CompileIncomplete> { compile_result_from_err_count(self.err_count()) } pub fn track_errors(&self, f: F) -> Result where F: FnOnce() -> T, { let old_count = self.err_count(); let result = f(); let errors = self.err_count() - old_count; if errors == 0 { 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) } pub fn opt_span_warn>(&self, opt_sp: Option, msg: &str) { match opt_sp { Some(sp) => self.span_warn(sp, msg), None => self.warn(msg), } } /// Delay a span_bug() call until abort_if_errors() pub fn delay_span_bug>(&self, sp: S, msg: &str) { self.diagnostic().delay_span_bug(sp, 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 span_unimpl>(&self, sp: S, msg: &str) -> ! { self.diagnostic().span_unimpl(sp, msg) } pub fn unimpl(&self, msg: &str) -> ! { self.diagnostic().unimpl(msg) } pub fn buffer_lint>( &self, lint: &'static lint::Lint, id: ast::NodeId, sp: S, msg: &str, ) { match *self.buffered_lints.borrow_mut() { Some(ref mut buffer) => { buffer.add_lint(lint, id, sp.into(), msg, BuiltinLintDiagnostics::Normal) } None => bug!("can't buffer lints after HIR lowering"), } } pub fn buffer_lint_with_diagnostic>( &self, lint: &'static lint::Lint, id: ast::NodeId, sp: S, msg: &str, diagnostic: BuiltinLintDiagnostics, ) { match *self.buffered_lints.borrow_mut() { Some(ref mut buffer) => buffer.add_lint(lint, id, sp.into(), msg, diagnostic), None => bug!("can't buffer lints after HIR lowering"), } } pub fn reserve_node_ids(&self, count: usize) -> ast::NodeId { let id = self.next_node_id.get(); match id.as_usize().checked_add(count) { Some(next) => { self.next_node_id.set(ast::NodeId::new(next)); } None => bug!("Input too large, ran out of node ids!"), } id } pub fn next_node_id(&self) -> NodeId { self.reserve_node_ids(1) } pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler { &self.parse_sess.span_diagnostic } /// 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); } DiagnosticBuilderMethod::SpanSuggestion(suggestion) => { let span = span_maybe.expect("span_suggestion needs a span"); diag_builder.span_suggestion(span, message, suggestion); } } } } 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, ); } pub fn diag_span_suggestion_once<'a, 'b>( &'a self, diag_builder: &'b mut DiagnosticBuilder<'a>, msg_id: DiagnosticMessageId, span: Span, message: &str, suggestion: String, ) { self.diag_once( diag_builder, DiagnosticBuilderMethod::SpanSuggestion(suggestion), msg_id, message, Some(span), ); } pub fn codemap<'a>(&'a self) -> &'a codemap::CodeMap { self.parse_sess.codemap() } pub fn verbose(&self) -> bool { self.opts.debugging_opts.verbose } pub fn time_passes(&self) -> bool { self.opts.debugging_opts.time_passes } pub fn profile_queries(&self) -> bool { self.opts.debugging_opts.profile_queries || self.opts.debugging_opts.profile_queries_and_keys } pub fn profile_queries_and_keys(&self) -> bool { self.opts.debugging_opts.profile_queries_and_keys } pub fn count_llvm_insns(&self) -> bool { self.opts.debugging_opts.count_llvm_insns } pub fn time_llvm_passes(&self) -> bool { self.opts.debugging_opts.time_llvm_passes } pub fn codegen_stats(&self) -> bool { self.opts.debugging_opts.codegen_stats } 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 no_verify(&self) -> bool { self.opts.debugging_opts.no_verify } pub fn borrowck_stats(&self) -> bool { self.opts.debugging_opts.borrowck_stats } pub fn print_llvm_passes(&self) -> bool { self.opts.debugging_opts.print_llvm_passes } /// Get 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) -> &feature_gate::Features { self.features.get() } pub fn init_features(&self, features: feature_gate::Features) { self.features.set(features); } /// 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.target.options.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::Lto::No => {} config::Lto::Yes if self.opts.cli_forced_thinlto_off => return config::Lto::Fat, other => return other, } // 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; } // Right now ThinLTO isn't compatible with incremental compilation. if self.opts.incremental.is_some() { 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.target.options.panic_strategy) } pub fn linker_flavor(&self) -> LinkerFlavor { self.opts .debugging_opts .linker_flavor .unwrap_or(self.target.target.linker_flavor) } pub fn fewer_names(&self) -> bool { let more_names = self.opts .output_types .contains_key(&OutputType::LlvmAssembly) || self.opts.output_types.contains_key(&OutputType::Bitcode); self.opts.debugging_opts.fewer_names || !more_names } pub fn no_landing_pads(&self) -> bool { self.opts.debugging_opts.no_landing_pads || self.panic_strategy() == PanicStrategy::Abort } pub fn unstable_options(&self) -> bool { self.opts.debugging_opts.unstable_options } pub fn nonzeroing_move_hints(&self) -> bool { self.opts.debugging_opts.enable_nonzeroing_move_hints } pub fn overflow_checks(&self) -> bool { self.opts .cg .overflow_checks .or(self.opts.debugging_opts.force_overflow_checks) .unwrap_or(self.opts.debug_assertions) } pub fn crt_static(&self) -> bool { // If the target does not opt in to crt-static support, use its default. if self.target.target.options.crt_static_respected { self.crt_static_feature() } else { self.target.target.options.crt_static_default } } pub fn crt_static_feature(&self) -> bool { 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 the target we're compiling for requests a static crt by default, // then see if the `-crt-static` feature was passed to disable that. // Otherwise if we don't have a static crt by default then see if the // `+crt-static` feature was passed. if self.target.target.options.crt_static_default { !found_negative } else { found_positive } } pub fn target_cpu(&self) -> &str { match self.opts.cg.target_cpu { Some(ref s) => &**s, None => &*self.target.target.options.cpu } } pub fn must_not_eliminate_frame_pointers(&self) -> bool { if let Some(x) = self.opts.cg.force_frame_pointers { x } else { !self.target.target.options.eliminate_frame_pointer } } /// Returns the symbol name for the registrar function, /// given the crate Svh and the function DefIndex. pub fn generate_plugin_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String { format!( "__rustc_plugin_registrar_{}__", disambiguator.to_fingerprint().to_hex() ) } pub fn generate_derive_registrar_symbol(&self, disambiguator: CrateDisambiguator) -> String { format!( "__rustc_derive_registrar_{}__", disambiguator.to_fingerprint().to_hex() ) } pub fn sysroot<'a>(&'a self) -> &'a Path { match self.opts.maybe_sysroot { Some(ref sysroot) => sysroot, None => self.default_sysroot .as_ref() .expect("missing sysroot and default_sysroot in Session"), } } pub fn target_filesearch(&self, kind: PathKind) -> filesearch::FileSearch { filesearch::FileSearch::new( self.sysroot(), self.opts.target_triple.triple(), &self.opts.search_paths, kind, ) } pub fn host_filesearch(&self, kind: PathKind) -> filesearch::FileSearch { filesearch::FileSearch::new( self.sysroot(), config::host_triple(), &self.opts.search_paths, kind, ) } pub fn set_incr_session_load_dep_graph(&self, load: bool) { let mut incr_comp_session = self.incr_comp_session.borrow_mut(); match *incr_comp_session { IncrCompSession::Active { ref mut load_dep_graph, .. } => { *load_dep_graph = load; } _ => {} } } pub fn incr_session_load_dep_graph(&self) -> bool { let incr_comp_session = self.incr_comp_session.borrow(); match *incr_comp_session { IncrCompSession::Active { load_dep_graph, .. } => load_dep_graph, _ => false, } } 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 { bug!( "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 { bug!( "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, _ => bug!( "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 { let incr_comp_session = self.incr_comp_session.borrow(); cell::Ref::map( incr_comp_session, |incr_comp_session| match *incr_comp_session { IncrCompSession::NotInitialized => bug!( "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> { if self.opts.incremental.is_some() { Some(self.incr_comp_session_dir()) } else { None } } pub fn print_perf_stats(&self) { println!( "Total time spent computing symbol hashes: {}", duration_to_secs_str(*self.perf_stats.symbol_hash_time.lock()) ); println!( "Total time spent decoding DefPath tables: {}", duration_to_secs_str(*self.perf_stats.decode_def_path_tables_time.lock()) ); println!("Total queries canonicalized: {}", self.perf_stats.queries_canonicalized.load(Ordering::Relaxed)); println!("normalize_ty_after_erasing_regions: {}", self.perf_stats.normalize_ty_after_erasing_regions.load(Ordering::Relaxed)); println!("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; match self.optimization_fuel_crate { Some(ref c) if c == crate_name => { assert!(self.query_threads() == 1); let fuel = self.optimization_fuel_limit.get(); ret = fuel != 0; if fuel == 0 && !self.out_of_fuel.get() { println!("optimization-fuel-exhausted: {}", msg()); self.out_of_fuel.set(true); } else if fuel > 0 { self.optimization_fuel_limit.set(fuel - 1); } } _ => {} } match self.print_fuel_crate { Some(ref c) if c == crate_name => { assert!(self.query_threads() == 1); self.print_fuel.set(self.print_fuel.get() + 1); } _ => {} } ret } /// Returns the number of query threads that should be used for this /// compilation pub fn query_threads_from_opts(opts: &config::Options) -> usize { opts.debugging_opts.query_threads.unwrap_or(1) } /// Returns the number of query threads that should be used for this /// compilation pub fn query_threads(&self) -> usize { Self::query_threads_from_opts(&self.opts) } /// 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.target.options.default_codegen_units { return n as usize; } // 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.parse_sess.span_diagnostic.must_teach(code) } /// Are we allowed to use features from the Rust 2018 edition? pub fn rust_2018(&self) -> bool { self.opts.edition >= Edition::Edition2018 } pub fn edition(&self) -> Edition { self.opts.edition } } pub fn build_session( sopts: config::Options, local_crate_source_file: Option, registry: errors::registry::Registry, ) -> Session { let file_path_mapping = sopts.file_path_mapping(); build_session_with_codemap( sopts, local_crate_source_file, registry, Lrc::new(codemap::CodeMap::new(file_path_mapping)), None, ) } pub fn build_session_with_codemap( sopts: config::Options, local_crate_source_file: Option, registry: errors::registry::Registry, codemap: Lrc, emitter_dest: 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 treat_err_as_bug = sopts.debugging_opts.treat_err_as_bug; let external_macro_backtrace = sopts.debugging_opts.external_macro_backtrace; let emitter: Box = match (sopts.error_format, emitter_dest) { (config::ErrorOutputType::HumanReadable(color_config), None) => Box::new( EmitterWriter::stderr( color_config, Some(codemap.clone()), false, sopts.debugging_opts.teach, ).ui_testing(sopts.debugging_opts.ui_testing), ), (config::ErrorOutputType::HumanReadable(_), Some(dst)) => Box::new( EmitterWriter::new(dst, Some(codemap.clone()), false, false) .ui_testing(sopts.debugging_opts.ui_testing), ), (config::ErrorOutputType::Json(pretty), None) => Box::new( JsonEmitter::stderr( Some(registry), codemap.clone(), pretty, ).ui_testing(sopts.debugging_opts.ui_testing), ), (config::ErrorOutputType::Json(pretty), Some(dst)) => Box::new( JsonEmitter::new( dst, Some(registry), codemap.clone(), pretty, ).ui_testing(sopts.debugging_opts.ui_testing), ), (config::ErrorOutputType::Short(color_config), None) => Box::new( EmitterWriter::stderr(color_config, Some(codemap.clone()), true, false), ), (config::ErrorOutputType::Short(_), Some(dst)) => { Box::new(EmitterWriter::new(dst, Some(codemap.clone()), true, false)) } }; let diagnostic_handler = errors::Handler::with_emitter_and_flags( emitter, errors::HandlerFlags { can_emit_warnings, treat_err_as_bug, external_macro_backtrace, ..Default::default() }, ); build_session_(sopts, local_crate_source_file, diagnostic_handler, codemap) } pub fn build_session_( sopts: config::Options, local_crate_source_file: Option, span_diagnostic: errors::Handler, codemap: Lrc, ) -> Session { let host_triple = TargetTriple::from_triple(config::host_triple()); let host = match Target::search(&host_triple) { Ok(t) => t, Err(e) => { span_diagnostic .fatal(&format!("Error loading host specification: {}", e)) .raise(); } }; let target_cfg = config::build_target_config(&sopts, &span_diagnostic); let p_s = parse::ParseSess::with_span_handler(span_diagnostic, codemap); let default_sysroot = match sopts.maybe_sysroot { Some(_) => None, None => Some(filesearch::get_or_default_sysroot()), }; 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_crate = sopts.debugging_opts.fuel.as_ref().map(|i| i.0.clone()); let optimization_fuel_limit = LockCell::new(sopts.debugging_opts.fuel.as_ref().map(|i| i.1).unwrap_or(0)); let print_fuel_crate = sopts.debugging_opts.print_fuel.clone(); let print_fuel = LockCell::new(0); let working_dir = match env::current_dir() { Ok(dir) => dir, Err(e) => p_s.span_diagnostic .fatal(&format!("Current directory is invalid: {}", e)) .raise(), }; let working_dir = file_path_mapping.map_prefix(working_dir); let sess = Session { target: target_cfg, host, opts: sopts, parse_sess: p_s, // For a library crate, this is always none entry_fn: Once::new(), plugin_registrar_fn: Once::new(), derive_registrar_fn: Once::new(), default_sysroot, local_crate_source_file, working_dir, lint_store: RwLock::new(lint::LintStore::new()), buffered_lints: Lock::new(Some(lint::LintBuffer::new())), one_time_diagnostics: Lock::new(FxHashSet()), plugin_llvm_passes: OneThread::new(RefCell::new(Vec::new())), plugin_attributes: OneThread::new(RefCell::new(Vec::new())), crate_types: Once::new(), dependency_formats: Once::new(), crate_disambiguator: Once::new(), features: Once::new(), recursion_limit: Once::new(), type_length_limit: Once::new(), const_eval_stack_frame_limit: 100, next_node_id: OneThread::new(Cell::new(NodeId::new(1))), injected_allocator: Once::new(), allocator_kind: Once::new(), injected_panic_runtime: Once::new(), imported_macro_spans: OneThread::new(RefCell::new(HashMap::new())), incr_comp_session: OneThread::new(RefCell::new(IncrCompSession::NotInitialized)), ignored_attr_names: ich::compute_ignored_attr_names(), profile_channel: Lock::new(None), perf_stats: PerfStats { symbol_hash_time: Lock::new(Duration::from_secs(0)), decode_def_path_tables_time: Lock::new(Duration::from_secs(0)), queries_canonicalized: AtomicUsize::new(0), normalize_ty_after_erasing_regions: AtomicUsize::new(0), normalize_projection_ty: AtomicUsize::new(0), }, code_stats: Lock::new(CodeStats::new()), optimization_fuel_crate, optimization_fuel_limit, print_fuel_crate, print_fuel, out_of_fuel: LockCell::new(false), // Note that this is unsafe because it may misinterpret file descriptors // on Unix as jobserver file descriptors. We hopefully execute this near // the beginning of the process though to ensure we don't get false // positives, or in other words we try to execute this before we open // any file descriptors ourselves. // // Pick a "reasonable maximum" if we don't otherwise have // a jobserver in our environment, capping out at 32 so we // don't take everything down by hogging the process run queue. // The fixed number is used to have deterministic compilation // across machines. // // Also note that we stick this in a global because there could be // multiple `Session` instances in this process, and the jobserver is // per-process. jobserver: unsafe { static mut GLOBAL_JOBSERVER: *mut Client = 0 as *mut _; static INIT: std::sync::Once = std::sync::ONCE_INIT; INIT.call_once(|| { let client = Client::from_env().unwrap_or_else(|| { Client::new(32).expect("failed to create jobserver") }); GLOBAL_JOBSERVER = Box::into_raw(Box::new(client)); }); (*GLOBAL_JOBSERVER).clone() }, has_global_allocator: Once::new(), }; sess } /// Hash value constructed out of all the `-C metadata` arguments passed to the /// compiler. Together with the crate-name forms a unique global identifier for /// the crate. #[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Clone, Copy, RustcEncodable, RustcDecodable)] pub struct CrateDisambiguator(Fingerprint); impl CrateDisambiguator { pub fn to_fingerprint(self) -> Fingerprint { self.0 } } impl From for CrateDisambiguator { fn from(fingerprint: Fingerprint) -> CrateDisambiguator { CrateDisambiguator(fingerprint) } } impl_stable_hash_for!(tuple_struct CrateDisambiguator { fingerprint }); /// 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(output: config::ErrorOutputType, msg: &str) -> ! { let emitter: Box = match output { config::ErrorOutputType::HumanReadable(color_config) => { Box::new(EmitterWriter::stderr(color_config, None, false, false)) } config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)), config::ErrorOutputType::Short(color_config) => { Box::new(EmitterWriter::stderr(color_config, None, true, false)) } }; let handler = errors::Handler::with_emitter(true, false, emitter); handler.emit(&MultiSpan::new(), msg, errors::Level::Fatal); errors::FatalError.raise(); } pub fn early_warn(output: config::ErrorOutputType, msg: &str) { let emitter: Box = match output { config::ErrorOutputType::HumanReadable(color_config) => { Box::new(EmitterWriter::stderr(color_config, None, false, false)) } config::ErrorOutputType::Json(pretty) => Box::new(JsonEmitter::basic(pretty)), config::ErrorOutputType::Short(color_config) => { Box::new(EmitterWriter::stderr(color_config, None, true, false)) } }; let handler = errors::Handler::with_emitter(true, false, emitter); handler.emit(&MultiSpan::new(), msg, errors::Level::Warning); } #[derive(Copy, Clone, Debug)] pub enum CompileIncomplete { Stopped, Errored(ErrorReported), } impl From for CompileIncomplete { fn from(err: ErrorReported) -> CompileIncomplete { CompileIncomplete::Errored(err) } } pub type CompileResult = Result<(), CompileIncomplete>; pub fn compile_result_from_err_count(err_count: usize) -> CompileResult { if err_count == 0 { Ok(()) } else { Err(CompileIncomplete::Errored(ErrorReported)) } } #[cold] #[inline(never)] pub fn bug_fmt(file: &'static str, line: u32, args: fmt::Arguments) -> ! { // this wrapper mostly exists so I don't have to write a fully // qualified path of None:: inside the bug!() macro definition opt_span_bug_fmt(file, line, None::, args); } #[cold] #[inline(never)] pub fn span_bug_fmt>( file: &'static str, line: u32, span: S, args: fmt::Arguments, ) -> ! { opt_span_bug_fmt(file, line, Some(span), args); } fn opt_span_bug_fmt>( file: &'static str, line: u32, span: Option, args: fmt::Arguments, ) -> ! { tls::with_opt(move |tcx| { let msg = format!("{}:{}: {}", file, line, args); match (tcx, span) { (Some(tcx), Some(span)) => tcx.sess.diagnostic().span_bug(span, &msg), (Some(tcx), None) => tcx.sess.diagnostic().bug(&msg), (None, _) => panic!(msg), } }); unreachable!(); }