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 /// Helper to ensure that queries only return `Copy` types.
 110 #[inline(always)]
 111 fn copy<T: Copy>(x: &T) -> T {
 112     *x
 113 }
 114
 115 macro_rules! query_helper_param_ty {
 116     (DefId) => { impl IntoQueryParam<DefId> };
 117     ($K:ty) => { $K };
 118 }
 119
 120 macro_rules! query_storage {
 121     ([][$K:ty, $V:ty]) => {
 122         <DefaultCacheSelector as CacheSelector<$K, $V>>::Cache
 123     };
 124     ([(storage $ty:ty) $($rest:tt)*][$K:ty, $V:ty]) => {
 125         <$ty as CacheSelector<$K, $V>>::Cache
 126     };
 127     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 128         query_storage!([$($modifiers)*][$($args)*])
 129     };
 130 }
 131
 132 macro_rules! separate_provide_extern_decl {
 133     ([][$name:ident]) => {
 134         ()
 135     };
 136     ([(separate_provide_extern) $($rest:tt)*][$name:ident]) => {
 137         for<'tcx> fn(
 138             TyCtxt<'tcx>,
 139             query_keys::$name<'tcx>,
 140         ) -> query_values::$name<'tcx>
 141     };
 142     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 143         separate_provide_extern_decl!([$($modifiers)*][$($args)*])
 144     };
 145 }
 146
 147 macro_rules! separate_provide_extern_default {
 148     ([][$name:ident]) => {
 149         ()
 150     };
 151     ([(separate_provide_extern) $($rest:tt)*][$name:ident]) => {
 152         |_, key| bug!(
 153             "`tcx.{}({:?})` unsupported by its crate; \
 154              perhaps the `{}` query was never assigned a provider function",
 155             stringify!($name),
 156             key,
 157             stringify!($name),
 158         )
 159     };
 160     ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
 161         separate_provide_extern_default!([$($modifiers)*][$($args)*])
 162     };
 163 }
 164
 165 macro_rules! opt_remap_env_constness {
 166     ([][$name:ident]) => {};
 167     ([(remap_env_constness) $($rest:tt)*][$name:ident]) => {
 168         let $name = $name.without_const();
 169     };
 170     ([$other:tt $($modifiers:tt)*][$name:ident]) => {
 171         opt_remap_env_constness!([$($modifiers)*][$name])
 172     };
 173 }
 174
 175 macro_rules! define_callbacks {
 176     (<$tcx:tt>
 177      $($(#[$attr:meta])*
 178         [$($modifiers:tt)*] fn $name:ident($($K:tt)*) -> $V:ty,)*) => {
 179
 180         // HACK(eddyb) this is like the `impl QueryConfig for queries::$name`
 181         // below, but using type aliases instead of associated types, to bypass
 182         // the limitations around normalizing under HRTB - for example, this:
 183         // `for<'tcx> fn(...) -> <queries::$name<'tcx> as QueryConfig<TyCtxt<'tcx>>>::Value`
 184         // doesn't currently normalize to `for<'tcx> fn(...) -> query_values::$name<'tcx>`.
 185         // This is primarily used by the `provide!` macro in `rustc_metadata`.
 186         #[allow(nonstandard_style, unused_lifetimes)]
 187         pub mod query_keys {
 188             use super::*;
 189
 190             $(pub type $name<$tcx> = $($K)*;)*
 191         }
 192         #[allow(nonstandard_style, unused_lifetimes)]
 193         pub mod query_values {
 194             use super::*;
 195
 196             $(pub type $name<$tcx> = $V;)*
 197         }
 198         #[allow(nonstandard_style, unused_lifetimes)]
 199         pub mod query_storage {
 200             use super::*;
 201
 202             $(pub type $name<$tcx> = query_storage!([$($modifiers)*][$($K)*, $V]);)*
 203         }
 204         #[allow(nonstandard_style, unused_lifetimes)]
 205         pub mod query_stored {
 206             use super::*;
 207
 208             $(pub type $name<$tcx> = <query_storage::$name<$tcx> as QueryStorage>::Stored;)*
 209         }
 210
 211         #[derive(Default)]
 212         pub struct QueryCaches<$tcx> {
 213             $($(#[$attr])* pub $name: QueryCacheStore<query_storage::$name<$tcx>>,)*
 214         }
 215
 216         impl<$tcx> TyCtxtEnsure<$tcx> {
 217             $($(#[$attr])*
 218             #[inline(always)]
 219             pub fn $name(self, key: query_helper_param_ty!($($K)*)) {
 220                 let key = key.into_query_param();
 221                 opt_remap_env_constness!([$($modifiers)*][key]);
 222
 223                 let cached = try_get_cached(self.tcx, &self.tcx.query_caches.$name, &key, noop);
 224
 225                 let lookup = match cached {
 226                     Ok(()) => return,
 227                     Err(lookup) => lookup,
 228                 };
 229
 230                 self.tcx.queries.$name(self.tcx, DUMMY_SP, key, lookup, QueryMode::Ensure);
 231             })*
 232         }
 233
 234         impl<$tcx> TyCtxt<$tcx> {
 235             $($(#[$attr])*
 236             #[inline(always)]
 237             #[must_use]
 238             pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> query_stored::$name<$tcx>
 239             {
 240                 self.at(DUMMY_SP).$name(key)
 241             })*
 242         }
 243
 244         impl<$tcx> TyCtxtAt<$tcx> {
 245             $($(#[$attr])*
 246             #[inline(always)]
 247             pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> query_stored::$name<$tcx>
 248             {
 249                 let key = key.into_query_param();
 250                 opt_remap_env_constness!([$($modifiers)*][key]);
 251
 252                 let cached = try_get_cached(self.tcx, &self.tcx.query_caches.$name, &key, copy);
 253
 254                 let lookup = match cached {
 255                     Ok(value) => return value,
 256                     Err(lookup) => lookup,
 257                 };
 258
 259                 self.tcx.queries.$name(self.tcx, self.span, key, lookup, QueryMode::Get).unwrap()
 260             })*
 261         }
 262
 263         pub struct Providers {
 264             $(pub $name: for<'tcx> fn(
 265                 TyCtxt<'tcx>,
 266                 query_keys::$name<'tcx>,
 267             ) -> query_values::$name<'tcx>,)*
 268         }
 269
 270         pub struct ExternProviders {
 271             $(pub $name: separate_provide_extern_decl!([$($modifiers)*][$name]),)*
 272         }
 273
 274         impl Default for Providers {
 275             fn default() -> Self {
 276                 Providers {
 277                     $($name: |_, key| bug!(
 278                         "`tcx.{}({:?})` unsupported by its crate; \
 279                          perhaps the `{}` query was never assigned a provider function",
 280                         stringify!($name),
 281                         key,
 282                         stringify!($name),
 283                     ),)*
 284                 }
 285             }
 286         }
 287
 288         impl Default for ExternProviders {
 289             fn default() -> Self {
 290                 ExternProviders {
 291                     $($name: separate_provide_extern_default!([$($modifiers)*][$name]),)*
 292                 }
 293             }
 294         }
 295
 296         impl Copy for Providers {}
 297         impl Clone for Providers {
 298             fn clone(&self) -> Self { *self }
 299         }
 300
 301         impl Copy for ExternProviders {}
 302         impl Clone for ExternProviders {
 303             fn clone(&self) -> Self { *self }
 304         }
 305
 306         pub trait QueryEngine<'tcx>: rustc_data_structures::sync::Sync {
 307             fn as_any(&'tcx self) -> &'tcx dyn std::any::Any;
 308
 309             fn try_mark_green(&'tcx self, tcx: TyCtxt<'tcx>, dep_node: &dep_graph::DepNode) -> bool;
 310
 311             $($(#[$attr])*
 312             fn $name(
 313                 &'tcx self,
 314                 tcx: TyCtxt<$tcx>,
 315                 span: Span,
 316                 key: query_keys::$name<$tcx>,
 317                 lookup: QueryLookup,
 318                 mode: QueryMode,
 319             ) -> Option<query_stored::$name<$tcx>>;)*
 320         }
 321     };
 322 }
 323
 324 // Each of these queries corresponds to a function pointer field in the
 325 // `Providers` struct for requesting a value of that type, and a method
 326 // on `tcx: TyCtxt` (and `tcx.at(span)`) for doing that request in a way
 327 // which memoizes and does dep-graph tracking, wrapping around the actual
 328 // `Providers` that the driver creates (using several `rustc_*` crates).
 329 //
 330 // The result type of each query must implement `Clone`, and additionally
 331 // `ty::query::values::Value`, which produces an appropriate placeholder
 332 // (error) value if the query resulted in a query cycle.
 333 // Queries marked with `fatal_cycle` do not need the latter implementation,
 334 // as they will raise an fatal error on query cycles instead.
 335
 336 rustc_query_append! { [define_callbacks!][<'tcx>] }
 337
 338 mod sealed {
 339     use super::{DefId, LocalDefId};
 340
 341     /// An analogue of the `Into` trait that's intended only for query paramaters.
 342     ///
 343     /// This exists to allow queries to accept either `DefId` or `LocalDefId` while requiring that the
 344     /// user call `to_def_id` to convert between them everywhere else.
 345     pub trait IntoQueryParam<P> {
 346         fn into_query_param(self) -> P;
 347     }
 348
 349     impl<P> IntoQueryParam<P> for P {
 350         #[inline(always)]
 351         fn into_query_param(self) -> P {
 352             self
 353         }
 354     }
 355
 356     impl<'a, P: Copy> IntoQueryParam<P> for &'a P {
 357         #[inline(always)]
 358         fn into_query_param(self) -> P {
 359             *self
 360         }
 361     }
 362
 363     impl IntoQueryParam<DefId> for LocalDefId {
 364         #[inline(always)]
 365         fn into_query_param(self) -> DefId {
 366             self.to_def_id()
 367         }
 368     }
 369 }
 370
 371 use sealed::IntoQueryParam;
 372
 373 impl<'tcx> TyCtxt<'tcx> {
 374     pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
 375         let def_id = def_id.into_query_param();
 376         self.opt_def_kind(def_id)
 377             .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
 378     }
 379 }
 380
 381 impl<'tcx> TyCtxtAt<'tcx> {
 382     pub fn def_kind(self, def_id: impl IntoQueryParam<DefId>) -> DefKind {
 383         let def_id = def_id.into_query_param();
 384         self.opt_def_kind(def_id)
 385             .unwrap_or_else(|| bug!("def_kind: unsupported node: {:?}", def_id))
 386     }
 387 }