compiler/rustc_middle/src/ty/query.rs

   1 use crate::dep_graph;
   2 use crate::infer::canonical::{self, Canonical};
   3 use crate::lint::LintLevelMap;
   4 use crate::metadata::ModChild;
   5 use crate::middle::codegen_fn_attrs::CodegenFnAttrs;
   6 use crate::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
   7 use crate::middle::lib_features::LibFeatures;
   8 use crate::middle::privacy::AccessLevels;
   9 use crate::middle::region;
  10 use crate::middle::resolve_lifetime::{
  11     LifetimeScopeForPath, ObjectLifetimeDefault, Region, ResolveLifetimes,
  12 };
  13 use crate::middle::stability::{self, DeprecationEntry};
  14 use crate::mir;
  15 use crate::mir::interpret::GlobalId;
  16 use crate::mir::interpret::{ConstAlloc, LitToConstError, LitToConstInput};
  17 use crate::mir::interpret::{ConstValue, EvalToAllocationRawResult, EvalToConstValueResult};
  18 use crate::mir::mono::CodegenUnit;
  19 use crate::thir;
  20 use crate::traits::query::{
  21     CanonicalPredicateGoal, CanonicalProjectionGoal, CanonicalTyGoal,
  22     CanonicalTypeOpAscribeUserTypeGoal, CanonicalTypeOpEqGoal, CanonicalTypeOpNormalizeGoal,
  23     CanonicalTypeOpProvePredicateGoal, CanonicalTypeOpSubtypeGoal, NoSolution,
  24 };
  25 use crate::traits::query::{
  26     DropckOutlivesResult, DtorckConstraint, MethodAutoderefStepsResult, NormalizationResult,
  27     OutlivesBound,
  28 };
  29 use crate::traits::specialization_graph;
  30 use crate::traits::{self, ImplSource};
  31 use crate::ty::fast_reject::SimplifiedType;
  32 use crate::ty::subst::{GenericArg, SubstsRef};
  33 use crate::ty::util::AlwaysRequiresDrop;
  34 use crate::ty::{self, AdtSizedConstraint, CrateInherentImpls, ParamEnvAnd, Ty, TyCtxt};
  35 use rustc_ast::expand::allocator::AllocatorKind;
  36 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
  37 use rustc_data_structures::steal::Steal;
  38 use rustc_data_structures::svh::Svh;
  39 use rustc_data_structures::sync::Lrc;
  40 use rustc_errors::ErrorReported;
  41 use rustc_hir as hir;
  42 use rustc_hir::def::DefKind;
  43 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefIdSet, LocalDefId};
  44 use rustc_hir::lang_items::{LangItem, LanguageItems};
  45 use rustc_hir::{Crate, ItemLocalId, TraitCandidate};
  46 use rustc_index::{bit_set::FiniteBitSet, vec::IndexVec};
  47 use rustc_session::config::{EntryFnType, OptLevel, OutputFilenames, SymbolManglingVersion};
  48 use rustc_session::cstore::{CrateDepKind, CrateSource};
  49 use rustc_session::cstore::{ExternCrate, ForeignModule, LinkagePreference, NativeLib};
  50 use rustc_session::utils::NativeLibKind;
  51 use rustc_session::Limits;
  52 use rustc_target::abi;
  53 use rustc_target::spec::PanicStrategy;
  54
  55 use rustc_ast as ast;
  56 use rustc_attr as attr;
  57 use rustc_span::symbol::Symbol;
  58 use rustc_span::{Span, DUMMY_SP};
  59 use std::collections::BTreeMap;
  60 use std::ops::Deref;
  61 use std::path::PathBuf;
  62 use std::sync::Arc;
  63
  64 pub(crate) use rustc_query_system::query::QueryJobId;
  65 use rustc_query_system::query::*;
  66
  67 #[derive(Copy, Clone)]
  68 pub struct TyCtxtAt<'tcx> {
  69     pub tcx: TyCtxt<'tcx>,
  70     pub span: Span,
  71 }
  72
  73 impl<'tcx> Deref for TyCtxtAt<'tcx> {
  74     type Target = TyCtxt<'tcx>;
  75     #[inline(always)]
  76     fn deref(&self) -> &Self::Target {
  77         &self.tcx
  78     }
  79 }
  80
  81 #[derive(Copy, Clone)]
  82 pub struct TyCtxtEnsure<'tcx> {
  83     pub tcx: TyCtxt<'tcx>,
  84 }
  85
  86 impl<'tcx> TyCtxt<'tcx> {
  87     /// Returns a transparent wrapper for `TyCtxt`, which ensures queries
  88     /// are executed instead of just returning their results.
  89     #[inline(always)]
  90     pub fn ensure(self) -> TyCtxtEnsure<'tcx> {
  91         TyCtxtEnsure { tcx: self }
  92     }
  93
  94     /// Returns a transparent wrapper for `TyCtxt` which uses
  95     /// `span` as the location of queries performed through it.
  96     #[inline(always)]
  97     pub fn at(self, span: Span) -> TyCtxtAt<'tcx> {
  98         TyCtxtAt { tcx: self, span }
  99     }
 100
 101     pub fn try_mark_green(self, dep_node: &dep_graph::DepNode) -> bool {
 102         self.queries.try_mark_green(self, dep_node)
 103     }
 104 }
 105
 106 /// Helper for `TyCtxtEnsure` to avoid a closure.
 107 #[inline(always)]
 108 fn noop<T>(_: &T) {}
 109
 110 macro_rules! query_helper_param_ty {
 111     (DefId) => { impl IntoQueryParam<DefId> };
 112     ($K:ty) => { $K };
 113 }
 114
 115 macro_rules! query_storage {
 116     ([][$K:ty, $V:ty]) => {
 117         <DefaultCacheSelector as CacheSelector<$K, $V>>::Cache
 118     };
 119     ([(storage $ty:ty) $($rest:tt)*][$K:ty, $V:ty]) => {
 120         <$ty as CacheSelector<$K, $V>>::Cache
 121     };
 122     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 123         query_storage!([$($modifiers)*][$($args)*])
 124     };
 125 }
 126
 127 macro_rules! separate_provide_extern_decl {
 128     ([][$name:ident]) => {
 129         ()
 130     };
 131     ([(separate_provide_extern) $($rest:tt)*][$name:ident]) => {
 132         for<'tcx> fn(
 133             TyCtxt<'tcx>,
 134             query_keys::$name<'tcx>,
 135         ) -> query_values::$name<'tcx>
 136     };
 137     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 138         separate_provide_extern_decl!([$($modifiers)*][$($args)*])
 139     };
 140 }
 141
 142 macro_rules! separate_provide_extern_default {
 143     ([][$name:ident]) => {
 144         ()
 145     };
 146     ([(separate_provide_extern) $($rest:tt)*][$name:ident]) => {
 147         |_, key| bug!(
 148             "`tcx.{}({:?})` unsupported by its crate; \
 149              perhaps the `{}` query was never assigned a provider function",
 150             stringify!($name),
 151             key,
 152             stringify!($name),
 153         )
 154     };
 155     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 156         separate_provide_extern_default!([$($modifiers)*][$($args)*])
 157     };
 158 }
 159
 160 macro_rules! opt_remap_env_constness {
 161     ([][$name:ident]) => {};
 162     ([(remap_env_constness) $($rest:tt)*][$name:ident]) => {
 163         let $name = $name.without_const();
 164     };
 165     ([$other:tt $($modifiers:tt)*][$name:ident]) => {
 166         opt_remap_env_constness!([$($modifiers)*][$name])
 167     };
 168 }
 169
 170 macro_rules! define_callbacks {
 171     (<$tcx:tt>
 172      $($(#[$attr:meta])*
 173         [$($modifiers:tt)*] fn $name:ident($($K:tt)*) -> $V:ty,)*) => {
 174
 175         // HACK(eddyb) this is like the `impl QueryConfig for queries::$name`
 176         // below, but using type aliases instead of associated types, to bypass
 177         // the limitations around normalizing under HRTB - for example, this:
 178         // `for<'tcx> fn(...) -> <queries::$name<'tcx> as QueryConfig<TyCtxt<'tcx>>>::Value`
 179         // doesn't currently normalize to `for<'tcx> fn(...) -> query_values::$name<'tcx>`.
 180         // This is primarily used by the `provide!` macro in `rustc_metadata`.
 181         #[allow(nonstandard_style, unused_lifetimes)]
 182         pub mod query_keys {
 183             use super::*;
 184
 185             $(pub type $name<$tcx> = $($K)*;)*
 186         }
 187         #[allow(nonstandard_style, unused_lifetimes)]
 188         pub mod query_values {
 189             use super::*;
 190
 191             $(pub type $name<$tcx> = $V;)*
 192         }
 193         #[allow(nonstandard_style, unused_lifetimes)]
 194         pub mod query_storage {
 195             use super::*;
 196
 197             $(pub type $name<$tcx> = query_storage!([$($modifiers)*][$($K)*, $V]);)*
 198         }
 199         #[allow(nonstandard_style, unused_lifetimes)]
 200         pub mod query_stored {
 201             use super::*;
 202
 203             $(pub type $name<$tcx> = <query_storage::$name<$tcx> as QueryStorage>::Stored;)*
 204         }
 205
 206         #[derive(Default)]
 207         pub struct QueryCaches<$tcx> {
 208             $($(#[$attr])* pub $name: QueryCacheStore<query_storage::$name<$tcx>>,)*
 209         }
 210
 211         impl<$tcx> TyCtxtEnsure<$tcx> {
 212             $($(#[$attr])*
 213             #[inline(always)]
 214             pub fn $name(self, key: query_helper_param_ty!($($K)*)) {
 215                 let key = key.into_query_param();
 216                 opt_remap_env_constness!([$($modifiers)*][key]);
 217
 218                 let cached = try_get_cached(self.tcx, &self.tcx.query_caches.$name, &key, noop);
 219
 220                 let lookup = match cached {
 221                     Ok(()) => return,
 222                     Err(lookup) => lookup,
 223                 };
 224
 225                 self.tcx.queries.$name(self.tcx, DUMMY_SP, key, lookup, QueryMode::Ensure);
 226             })*
 227         }
 228
 229         impl<$tcx> TyCtxt<$tcx> {
 230             $($(#[$attr])*
 231             #[inline(always)]
 232             #[must_use]
 233             pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> query_stored::$name<$tcx>
 234             {
 235                 self.at(DUMMY_SP).$name(key)
 236             })*
 237         }
 238
 239         impl<$tcx> TyCtxtAt<$tcx> {
 240             $($(#[$attr])*
 241             #[inline(always)]
 242             pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> query_stored::$name<$tcx>
 243             {
 244                 let key = key.into_query_param();
 245                 opt_remap_env_constness!([$($modifiers)*][key]);
 246
 247                 let cached = try_get_cached(self.tcx, &self.tcx.query_caches.$name, &key, Clone::clone);
 248
 249                 let lookup = match cached {
 250                     Ok(value) => return value,
 251                     Err(lookup) => lookup,
 252                 };
 253
 254                 self.tcx.queries.$name(self.tcx, self.span, key, lookup, QueryMode::Get).unwrap()
 255             })*
 256         }
 257
 258         pub struct Providers {
 259             $(pub $name: for<'tcx> fn(
 260                 TyCtxt<'tcx>,
 261                 query_keys::$name<'tcx>,
 262             ) -> query_values::$name<'tcx>,)*
 263         }
 264
 265         pub struct ExternProviders {
 266             $(pub $name: separate_provide_extern_decl!([$($modifiers)*][$name]),)*
 267         }
 268
 269         impl Default for Providers {
 270             fn default() -> Self {
 271                 Providers {
 272                     $($name: |_, key| bug!(
 273                         "`tcx.{}({:?})` unsupported by its crate; \
 274                          perhaps the `{}` query was never assigned a provider function",
 275                         stringify!($name),
 276                         key,
 277                         stringify!($name),
 278                     ),)*
 279                 }
 280             }
 281         }
 282
 283         impl Default for ExternProviders {
 284             fn default() -> Self {
 285                 ExternProviders {
 286                     $($name: separate_provide_extern_default!([$($modifiers)*][$name]),)*
 287                 }
 288             }
 289         }
 290
 291         impl Copy for Providers {}
 292         impl Clone for Providers {
 293             fn clone(&self) -> Self { *self }
 294         }
 295
 296         impl Copy for ExternProviders {}
 297         impl Clone for ExternProviders {
 298             fn clone(&self) -> Self { *self }
 299         }
 300
 301         pub trait QueryEngine<'tcx>: rustc_data_structures::sync::Sync {
 302             fn as_any(&'tcx self) -> &'tcx dyn std::any::Any;
 303
 304             fn try_mark_green(&'tcx self, tcx: TyCtxt<'tcx>, dep_node: &dep_graph::DepNode) -> bool;
 305
 306             $($(#[$attr])*
 307             fn $name(
 308                 &'tcx self,
 309                 tcx: TyCtxt<$tcx>,
 310                 span: Span,
 311                 key: query_keys::$name<$tcx>,
 312                 lookup: QueryLookup,
 313                 mode: QueryMode,
 314             ) -> Option<query_stored::$name<$tcx>>;)*
 315         }
 316     };
 317 }
 318
 319 // Each of these queries corresponds to a function pointer field in the
 320 // `Providers` struct for requesting a value of that type, and a method
 321 // on `tcx: TyCtxt` (and `tcx.at(span)`) for doing that request in a way
 322 // which memoizes and does dep-graph tracking, wrapping around the actual
 323 // `Providers` that the driver creates (using several `rustc_*` crates).
 324 //
 325 // The result type of each query must implement `Clone`, and additionally
 326 // `ty::query::values::Value`, which produces an appropriate placeholder
 327 // (error) value if the query resulted in a query cycle.
 328 // Queries marked with `fatal_cycle` do not need the latter implementation,
 329 // as they will raise an fatal error on query cycles instead.
 330
 331 rustc_query_append! { [define_callbacks!][<'tcx>] }
 332
 333 mod sealed {
 334     use super::{DefId, LocalDefId};
 335
 336     /// An analogue of the `Into` trait that's intended only for query paramaters.
 337     ///
 338     /// This exists to allow queries to accept either `DefId` or `LocalDefId` while requiring that the
 339     /// user call `to_def_id` to convert between them everywhere else.
 340     pub trait IntoQueryParam<P> {
 341         fn into_query_param(self) -> P;
 342     }
 343
 344     impl<P> IntoQueryParam<P> for P {
 345         #[inline(always)]
 346         fn into_query_param(self) -> P {
 347             self
 348         }
 349     }
 350
 351     impl IntoQueryParam<DefId> for LocalDefId {
 352         #[inline(always)]
 353         fn into_query_param(self) -> DefId {
 354             self.to_def_id()
 355         }
 356     }
 357 }
 358
 359 use sealed::IntoQueryParam;
 360
 361 impl<'tcx> TyCtxt<'tcx> {
 362     pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
 363         let def_id = def_id.into_query_param();
 364         self.opt_def_kind(def_id)
 365             .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
 366     }
 367 }
 368
 369 impl<'tcx> TyCtxtAt<'tcx> {
 370     pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
 371         let def_id = def_id.into_query_param();
 372         self.opt_def_kind(def_id)
 373             .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
 374     }
 375 }