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::ops::Deref;
  60 use std::path::PathBuf;
  61 use std::sync::Arc;
  62
  63 pub(crate) use rustc_query_system::query::QueryJobId;
  64 use rustc_query_system::query::*;
  65
  66 #[derive(Copy, Clone)]
  67 pub struct TyCtxtAt<'tcx> {
  68     pub tcx: TyCtxt<'tcx>,
  69     pub span: Span,
  70 }
  71
  72 impl<'tcx> Deref for TyCtxtAt<'tcx> {
  73     type Target = TyCtxt<'tcx>;
  74     #[inline(always)]
  75     fn deref(&self) -> &Self::Target {
  76         &self.tcx
  77     }
  78 }
  79
  80 #[derive(Copy, Clone)]
  81 pub struct TyCtxtEnsure<'tcx> {
  82     pub tcx: TyCtxt<'tcx>,
  83 }
  84
  85 impl<'tcx> TyCtxt<'tcx> {
  86     /// Returns a transparent wrapper for `TyCtxt`, which ensures queries
  87     /// are executed instead of just returning their results.
  88     #[inline(always)]
  89     pub fn ensure(self) -> TyCtxtEnsure<'tcx> {
  90         TyCtxtEnsure { tcx: self }
  91     }
  92
  93     /// Returns a transparent wrapper for `TyCtxt` which uses
  94     /// `span` as the location of queries performed through it.
  95     #[inline(always)]
  96     pub fn at(self, span: Span) -> TyCtxtAt<'tcx> {
  97         TyCtxtAt { tcx: self, span }
  98     }
  99
 100     pub fn try_mark_green(self, dep_node: &dep_graph::DepNode) -> bool {
 101         self.queries.try_mark_green(self, dep_node)
 102     }
 103 }
 104
 105 /// Helper for `TyCtxtEnsure` to avoid a closure.
 106 #[inline(always)]
 107 fn noop<T>(_: &T) {}
 108
 109 macro_rules! query_helper_param_ty {
 110     (DefId) => { impl IntoQueryParam<DefId> };
 111     ($K:ty) => { $K };
 112 }
 113
 114 macro_rules! query_storage {
 115     ([][$K:ty, $V:ty]) => {
 116         <DefaultCacheSelector as CacheSelector<$K, $V>>::Cache
 117     };
 118     ([(storage $ty:ty) $($rest:tt)*][$K:ty, $V:ty]) => {
 119         <$ty as CacheSelector<$K, $V>>::Cache
 120     };
 121     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 122         query_storage!([$($modifiers)*][$($args)*])
 123     };
 124 }
 125
 126 macro_rules! separate_provide_extern_decl {
 127     ([][$name:ident]) => {
 128         ()
 129     };
 130     ([(separate_provide_extern) $($rest:tt)*][$name:ident]) => {
 131         for<'tcx> fn(
 132             TyCtxt<'tcx>,
 133             query_keys::$name<'tcx>,
 134         ) -> query_values::$name<'tcx>
 135     };
 136     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 137         separate_provide_extern_decl!([$($modifiers)*][$($args)*])
 138     };
 139 }
 140
 141 macro_rules! separate_provide_extern_default {
 142     ([][$name:ident]) => {
 143         ()
 144     };
 145     ([(separate_provide_extern) $($rest:tt)*][$name:ident]) => {
 146         |_, key| bug!(
 147             "`tcx.{}({:?})` unsupported by its crate; \
 148              perhaps the `{}` query was never assigned a provider function",
 149             stringify!($name),
 150             key,
 151             stringify!($name),
 152         )
 153     };
 154     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 155         separate_provide_extern_default!([$($modifiers)*][$($args)*])
 156     };
 157 }
 158
 159 macro_rules! opt_remap_env_constness {
 160     ([][$name:ident]) => {};
 161     ([(remap_env_constness) $($rest:tt)*][$name:ident]) => {
 162         let $name = $name.without_const();
 163     };
 164     ([$other:tt $($modifiers:tt)*][$name:ident]) => {
 165         opt_remap_env_constness!([$($modifiers)*][$name])
 166     };
 167 }
 168
 169 macro_rules! define_callbacks {
 170     (<$tcx:tt>
 171      $($(#[$attr:meta])*
 172         [$($modifiers:tt)*] fn $name:ident($($K:tt)*) -> $V:ty,)*) => {
 173
 174         // HACK(eddyb) this is like the `impl QueryConfig for queries::$name`
 175         // below, but using type aliases instead of associated types, to bypass
 176         // the limitations around normalizing under HRTB - for example, this:
 177         // `for<'tcx> fn(...) -> <queries::$name<'tcx> as QueryConfig<TyCtxt<'tcx>>>::Value`
 178         // doesn't currently normalize to `for<'tcx> fn(...) -> query_values::$name<'tcx>`.
 179         // This is primarily used by the `provide!` macro in `rustc_metadata`.
 180         #[allow(nonstandard_style, unused_lifetimes)]
 181         pub mod query_keys {
 182             use super::*;
 183
 184             $(pub type $name<$tcx> = $($K)*;)*
 185         }
 186         #[allow(nonstandard_style, unused_lifetimes)]
 187         pub mod query_values {
 188             use super::*;
 189
 190             $(pub type $name<$tcx> = $V;)*
 191         }
 192         #[allow(nonstandard_style, unused_lifetimes)]
 193         pub mod query_storage {
 194             use super::*;
 195
 196             $(pub type $name<$tcx> = query_storage!([$($modifiers)*][$($K)*, $V]);)*
 197         }
 198         #[allow(nonstandard_style, unused_lifetimes)]
 199         pub mod query_stored {
 200             use super::*;
 201
 202             $(pub type $name<$tcx> = <query_storage::$name<$tcx> as QueryStorage>::Stored;)*
 203         }
 204
 205         #[derive(Default)]
 206         pub struct QueryCaches<$tcx> {
 207             $($(#[$attr])* pub $name: QueryCacheStore<query_storage::$name<$tcx>>,)*
 208         }
 209
 210         impl<$tcx> TyCtxtEnsure<$tcx> {
 211             $($(#[$attr])*
 212             #[inline(always)]
 213             pub fn $name(self, key: query_helper_param_ty!($($K)*)) {
 214                 let key = key.into_query_param();
 215                 opt_remap_env_constness!([$($modifiers)*][key]);
 216
 217                 let cached = try_get_cached(self.tcx, &self.tcx.query_caches.$name, &key, noop);
 218
 219                 let lookup = match cached {
 220                     Ok(()) => return,
 221                     Err(lookup) => lookup,
 222                 };
 223
 224                 self.tcx.queries.$name(self.tcx, DUMMY_SP, key, lookup, QueryMode::Ensure);
 225             })*
 226         }
 227
 228         impl<$tcx> TyCtxt<$tcx> {
 229             $($(#[$attr])*
 230             #[inline(always)]
 231             #[must_use]
 232             pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> query_stored::$name<$tcx>
 233             {
 234                 self.at(DUMMY_SP).$name(key)
 235             })*
 236         }
 237
 238         impl<$tcx> TyCtxtAt<$tcx> {
 239             $($(#[$attr])*
 240             #[inline(always)]
 241             pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> query_stored::$name<$tcx>
 242             {
 243                 let key = key.into_query_param();
 244                 opt_remap_env_constness!([$($modifiers)*][key]);
 245
 246                 let cached = try_get_cached(self.tcx, &self.tcx.query_caches.$name, &key, Clone::clone);
 247
 248                 let lookup = match cached {
 249                     Ok(value) => return value,
 250                     Err(lookup) => lookup,
 251                 };
 252
 253                 self.tcx.queries.$name(self.tcx, self.span, key, lookup, QueryMode::Get).unwrap()
 254             })*
 255         }
 256
 257         pub struct Providers {
 258             $(pub $name: for<'tcx> fn(
 259                 TyCtxt<'tcx>,
 260                 query_keys::$name<'tcx>,
 261             ) -> query_values::$name<'tcx>,)*
 262         }
 263
 264         pub struct ExternProviders {
 265             $(pub $name: separate_provide_extern_decl!([$($modifiers)*][$name]),)*
 266         }
 267
 268         impl Default for Providers {
 269             fn default() -> Self {
 270                 Providers {
 271                     $($name: |_, key| bug!(
 272                         "`tcx.{}({:?})` unsupported by its crate; \
 273                          perhaps the `{}` query was never assigned a provider function",
 274                         stringify!($name),
 275                         key,
 276                         stringify!($name),
 277                     ),)*
 278                 }
 279             }
 280         }
 281
 282         impl Default for ExternProviders {
 283             fn default() -> Self {
 284                 ExternProviders {
 285                     $($name: separate_provide_extern_default!([$($modifiers)*][$name]),)*
 286                 }
 287             }
 288         }
 289
 290         impl Copy for Providers {}
 291         impl Clone for Providers {
 292             fn clone(&self) -> Self { *self }
 293         }
 294
 295         impl Copy for ExternProviders {}
 296         impl Clone for ExternProviders {
 297             fn clone(&self) -> Self { *self }
 298         }
 299
 300         pub trait QueryEngine<'tcx>: rustc_data_structures::sync::Sync {
 301             fn as_any(&'tcx self) -> &'tcx dyn std::any::Any;
 302
 303             fn try_mark_green(&'tcx self, tcx: TyCtxt<'tcx>, dep_node: &dep_graph::DepNode) -> bool;
 304
 305             $($(#[$attr])*
 306             fn $name(
 307                 &'tcx self,
 308                 tcx: TyCtxt<$tcx>,
 309                 span: Span,
 310                 key: query_keys::$name<$tcx>,
 311                 lookup: QueryLookup,
 312                 mode: QueryMode,
 313             ) -> Option<query_stored::$name<$tcx>>;)*
 314         }
 315     };
 316 }
 317
 318 // Each of these queries corresponds to a function pointer field in the
 319 // `Providers` struct for requesting a value of that type, and a method
 320 // on `tcx: TyCtxt` (and `tcx.at(span)`) for doing that request in a way
 321 // which memoizes and does dep-graph tracking, wrapping around the actual
 322 // `Providers` that the driver creates (using several `rustc_*` crates).
 323 //
 324 // The result type of each query must implement `Clone`, and additionally
 325 // `ty::query::values::Value`, which produces an appropriate placeholder
 326 // (error) value if the query resulted in a query cycle.
 327 // Queries marked with `fatal_cycle` do not need the latter implementation,
 328 // as they will raise an fatal error on query cycles instead.
 329
 330 rustc_query_append! { [define_callbacks!][<'tcx>] }
 331
 332 mod sealed {
 333     use super::{DefId, LocalDefId};
 334
 335     /// An analogue of the `Into` trait that's intended only for query paramaters.
 336     ///
 337     /// This exists to allow queries to accept either `DefId` or `LocalDefId` while requiring that the
 338     /// user call `to_def_id` to convert between them everywhere else.
 339     pub trait IntoQueryParam<P> {
 340         fn into_query_param(self) -> P;
 341     }
 342
 343     impl<P> IntoQueryParam<P> for P {
 344         #[inline(always)]
 345         fn into_query_param(self) -> P {
 346             self
 347         }
 348     }
 349
 350     impl IntoQueryParam<DefId> for LocalDefId {
 351         #[inline(always)]
 352         fn into_query_param(self) -> DefId {
 353             self.to_def_id()
 354         }
 355     }
 356 }
 357
 358 use sealed::IntoQueryParam;
 359
 360 impl<'tcx> TyCtxt<'tcx> {
 361     pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
 362         let def_id = def_id.into_query_param();
 363         self.opt_def_kind(def_id)
 364             .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
 365     }
 366 }
 367
 368 impl<'tcx> TyCtxtAt<'tcx> {
 369     pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
 370         let def_id = def_id.into_query_param();
 371         self.opt_def_kind(def_id)
 372             .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
 373     }
 374 }