Put all cached values into a central struct instead of just the stable hash

compiler/rustc_data_structures/src/intern.rs

@@ -4,8 +4,6 @@ use std::hash::{Hash, Hasher};
 use std::ops::Deref;
 use std::ptr;
 
-use crate::fingerprint::Fingerprint;
-
 mod private {
     #[derive(Clone, Copy, Debug)]
     pub struct PrivateZst;
@@ -110,86 +108,5 @@ where
     }
 }
 
-/// A helper type that you can wrap round your own type in order to automatically
-/// cache the stable hash on creation and not recompute it whenever the stable hash
-/// of the type is computed.
-/// This is only done in incremental mode. You can also opt out of caching by using
-/// StableHash::ZERO for the hash, in which case the hash gets computed each time.
-/// This is useful if you have values that you intern but never (can?) use for stable
-/// hashing.
-#[derive(Copy, Clone)]
-pub struct WithStableHash<T> {
-    pub internee: T,
-    pub stable_hash: Fingerprint,
-}
-
-impl<T: PartialEq> PartialEq for WithStableHash<T> {
-    #[inline]
-    fn eq(&self, other: &Self) -> bool {
-        self.internee.eq(&other.internee)
-    }
-}
-
-impl<T: Eq> Eq for WithStableHash<T> {}
-
-impl<T: Ord> PartialOrd for WithStableHash<T> {
-    fn partial_cmp(&self, other: &WithStableHash<T>) -> Option<Ordering> {
-        Some(self.internee.cmp(&other.internee))
-    }
-}
-
-impl<T: Ord> Ord for WithStableHash<T> {
-    fn cmp(&self, other: &WithStableHash<T>) -> Ordering {
-        self.internee.cmp(&other.internee)
-    }
-}
-
-impl<T> Deref for WithStableHash<T> {
-    type Target = T;
-
-    #[inline]
-    fn deref(&self) -> &T {
-        &self.internee
-    }
-}
-
-impl<T: Hash> Hash for WithStableHash<T> {
-    #[inline]
-    fn hash<H: Hasher>(&self, s: &mut H) {
-        if self.stable_hash != Fingerprint::ZERO {
-            self.stable_hash.hash(s)
-        } else {
-            self.internee.hash(s)
-        }
-    }
-}
-
-impl<T: HashStable<CTX>, CTX> HashStable<CTX> for WithStableHash<T> {
-    fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
-        if self.stable_hash == Fingerprint::ZERO || cfg!(debug_assertions) {
-            // No cached hash available. This can only mean that incremental is disabled.
-            // We don't cache stable hashes in non-incremental mode, because they are used
-            // so rarely that the performance actually suffers.
-
-            // We need to build the hash as if we cached it and then hash that hash, as
-            // otherwise the hashes will differ between cached and non-cached mode.
-            let stable_hash: Fingerprint = {
-                let mut hasher = StableHasher::new();
-                self.internee.hash_stable(hcx, &mut hasher);
-                hasher.finish()
-            };
-            if cfg!(debug_assertions) && self.stable_hash != Fingerprint::ZERO {
-                assert_eq!(
-                    stable_hash, self.stable_hash,
-                    "cached stable hash does not match freshly computed stable hash"
-                );
-            }
-            stable_hash.hash_stable(hcx, hasher);
-        } else {
-            self.stable_hash.hash_stable(hcx, hasher);
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests;

compiler/rustc_lint/src/pass_by_value.rs

@@ -10,7 +10,7 @@ declare_tool_lint! {
     /// The `rustc_pass_by_value` lint marks a type with `#[rustc_pass_by_value]` requiring it to
     /// always be passed by value. This is usually used for types that are thin wrappers around
     /// references, so there is no benefit to an extra layer of indirection. (Example: `Ty` which
-    /// is a reference to an `Interned<TyS>`)
+    /// is a reference to an `Interned<TyKind>`)
     pub rustc::PASS_BY_VALUE,
     Warn,
     "pass by reference of a type flagged as `#[rustc_pass_by_value]`",

compiler/rustc_middle/src/arena.rs

@@ -1,3 +1,5 @@
+#![allow(rustc::usage_of_ty_tykind)]
+
 /// This higher-order macro declares a list of types which can be allocated by `Arena`.
 ///
 /// Specifying the `decode` modifier will add decode impls for `&T` and `&[T]` where `T` is the type
@@ -88,8 +90,8 @@ macro_rules! arena_types {
             [] hir_id_set: rustc_hir::HirIdSet,
 
             // Interned types
-            [] tys: rustc_data_structures::intern::WithStableHash<rustc_middle::ty::TyS<'tcx>>,
-            [] predicates: rustc_data_structures::intern::WithStableHash<rustc_middle::ty::PredicateS<'tcx>>,
+            [] tys: rustc_type_ir::WithCachedTypeInfo<rustc_middle::ty::TyKind<'tcx>>,
+            [] predicates: rustc_type_ir::WithCachedTypeInfo<rustc_middle::ty::PredicateKind<'tcx>>,
             [] consts: rustc_middle::ty::ConstS<'tcx>,
 
             // Note that this deliberately duplicates items in the `rustc_hir::arena`,

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -103,7 +103,7 @@ impl hash::Hash for Allocation {
 /// Interned types generally have an `Outer` type and an `Inner` type, where
 /// `Outer` is a newtype around `Interned<Inner>`, and all the operations are
 /// done on `Outer`, because all occurrences are interned. E.g. `Ty` is an
-/// outer type and `TyS` is its inner type.
+/// outer type and `TyKind` is its inner type.
 ///
 /// Here things are different because only const allocations are interned. This
 /// means that both the inner type (`Allocation`) and the outer type

compiler/rustc_middle/src/ty/context.rs

@@ -1,5 +1,7 @@
 //! Type context book-keeping.
 
+#![allow(rustc::usage_of_ty_tykind)]
+
 use crate::arena::Arena;
 use crate::dep_graph::{DepGraph, DepKindStruct};
 use crate::hir::place::Place as HirPlace;
@@ -19,15 +21,15 @@ use crate::ty::{
     self, AdtDef, AdtDefData, AdtKind, Binder, BindingMode, BoundVar, CanonicalPolyFnSig,
     ClosureSizeProfileData, Const, ConstS, DefIdTree, FloatTy, FloatVar, FloatVid,
     GenericParamDefKind, InferTy, IntTy, IntVar, IntVid, List, ParamConst, ParamTy,
-    PolyExistentialPredicate, PolyFnSig, Predicate, PredicateKind, PredicateS, ProjectionTy,
-    Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyS, TyVar, TyVid, TypeAndMut,
-    UintTy, Visibility,
+    PolyExistentialPredicate, PolyFnSig, Predicate, PredicateKind, ProjectionTy, Region,
+    RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyVar, TyVid, TypeAndMut, UintTy,
+    Visibility,
 };
 use crate::ty::{GenericArg, GenericArgKind, InternalSubsts, SubstsRef, UserSubsts};
 use rustc_ast as ast;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_data_structures::intern::{Interned, WithStableHash};
+use rustc_data_structures::intern::Interned;
 use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_data_structures::sharded::{IntoPointer, ShardedHashMap};
@@ -67,6 +69,7 @@ use rustc_span::{Span, DUMMY_SP};
 use rustc_target::abi::{Layout, LayoutS, TargetDataLayout, VariantIdx};
 use rustc_target::spec::abi;
 use rustc_type_ir::sty::TyKind::*;
+use rustc_type_ir::WithCachedTypeInfo;
 use rustc_type_ir::{DynKind, InternAs, InternIteratorElement, Interner, TypeFlags};
 
 use std::any::Any;
@@ -136,13 +139,13 @@ pub struct CtxtInterners<'tcx> {
 
     // Specifically use a speedy hash algorithm for these hash sets, since
     // they're accessed quite often.
-    type_: InternedSet<'tcx, WithStableHash<TyS<'tcx>>>,
+    type_: InternedSet<'tcx, WithCachedTypeInfo<TyKind<'tcx>>>,
     const_lists: InternedSet<'tcx, List<ty::Const<'tcx>>>,
     substs: InternedSet<'tcx, InternalSubsts<'tcx>>,
     canonical_var_infos: InternedSet<'tcx, List<CanonicalVarInfo<'tcx>>>,
     region: InternedSet<'tcx, RegionKind<'tcx>>,
     poly_existential_predicates: InternedSet<'tcx, List<PolyExistentialPredicate<'tcx>>>,
-    predicate: InternedSet<'tcx, WithStableHash<PredicateS<'tcx>>>,
+    predicate: InternedSet<'tcx, WithCachedTypeInfo<ty::Binder<'tcx, PredicateKind<'tcx>>>>,
     predicates: InternedSet<'tcx, List<Predicate<'tcx>>>,
     projs: InternedSet<'tcx, List<ProjectionKind>>,
     place_elems: InternedSet<'tcx, List<PlaceElem<'tcx>>>,
@@ -193,15 +196,12 @@ impl<'tcx> CtxtInterners<'tcx> {
                     let stable_hash =
                         self.stable_hash(&flags, sess, definitions, cstore, source_span, &kind);
 
-                    let ty_struct = TyS {
-                        kind,
+                    InternedInSet(self.arena.alloc(WithCachedTypeInfo {
+                        internee: kind,
+                        stable_hash,
                         flags: flags.flags,
                         outer_exclusive_binder: flags.outer_exclusive_binder,
-                    };
-
-                    InternedInSet(
-                        self.arena.alloc(WithStableHash { internee: ty_struct, stable_hash }),
-                    )
+                    }))
                 })
                 .0,
         ))
@@ -245,16 +245,12 @@ impl<'tcx> CtxtInterners<'tcx> {
                     let stable_hash =
                         self.stable_hash(&flags, sess, definitions, cstore, source_span, &kind);
 
-                    let predicate_struct = PredicateS {
-                        kind,
+                    InternedInSet(self.arena.alloc(WithCachedTypeInfo {
+                        internee: kind,
+                        stable_hash,
                         flags: flags.flags,
                         outer_exclusive_binder: flags.outer_exclusive_binder,
-                    };
-
-                    InternedInSet(
-                        self.arena
-                            .alloc(WithStableHash { internee: predicate_struct, stable_hash }),
-                    )
+                    }))
                 })
                 .0,
         ))
@@ -2057,7 +2053,7 @@ macro_rules! sty_debug_print {
                 let shards = tcx.interners.type_.lock_shards();
                 let types = shards.iter().flat_map(|shard| shard.keys());
                 for &InternedInSet(t) in types {
-                    let variant = match t.kind {
+                    let variant = match t.internee {
                         ty::Bool | ty::Char | ty::Int(..) | ty::Uint(..) |
                             ty::Float(..) | ty::Str | ty::Never => continue,
                         ty::Error(_) => /* unimportant */ continue,
@@ -2167,51 +2163,26 @@ impl<'tcx, T: 'tcx + ?Sized> IntoPointer for InternedInSet<'tcx, T> {
 }
 
 #[allow(rustc::usage_of_ty_tykind)]
-impl<'tcx> Borrow<TyKind<'tcx>> for InternedInSet<'tcx, WithStableHash<TyS<'tcx>>> {
-    fn borrow<'a>(&'a self) -> &'a TyKind<'tcx> {
-        &self.0.kind
-    }
-}
-
-impl<'tcx> PartialEq for InternedInSet<'tcx, WithStableHash<TyS<'tcx>>> {
-    fn eq(&self, other: &InternedInSet<'tcx, WithStableHash<TyS<'tcx>>>) -> bool {
-        // The `Borrow` trait requires that `x.borrow() == y.borrow()` equals
-        // `x == y`.
-        self.0.kind == other.0.kind
-    }
-}
-
-impl<'tcx> Eq for InternedInSet<'tcx, WithStableHash<TyS<'tcx>>> {}
-
-impl<'tcx> Hash for InternedInSet<'tcx, WithStableHash<TyS<'tcx>>> {
-    fn hash<H: Hasher>(&self, s: &mut H) {
-        // The `Borrow` trait requires that `x.borrow().hash(s) == x.hash(s)`.
-        self.0.kind.hash(s)
-    }
-}
-
-impl<'tcx> Borrow<Binder<'tcx, PredicateKind<'tcx>>>
-    for InternedInSet<'tcx, WithStableHash<PredicateS<'tcx>>>
-{
-    fn borrow<'a>(&'a self) -> &'a Binder<'tcx, PredicateKind<'tcx>> {
-        &self.0.kind
+impl<'tcx, T> Borrow<T> for InternedInSet<'tcx, WithCachedTypeInfo<T>> {
+    fn borrow<'a>(&'a self) -> &'a T {
+        &self.0.internee
     }
 }
 
-impl<'tcx> PartialEq for InternedInSet<'tcx, WithStableHash<PredicateS<'tcx>>> {
-    fn eq(&self, other: &InternedInSet<'tcx, WithStableHash<PredicateS<'tcx>>>) -> bool {
+impl<'tcx, T: PartialEq> PartialEq for InternedInSet<'tcx, WithCachedTypeInfo<T>> {
+    fn eq(&self, other: &InternedInSet<'tcx, WithCachedTypeInfo<T>>) -> bool {
         // The `Borrow` trait requires that `x.borrow() == y.borrow()` equals
         // `x == y`.
-        self.0.kind == other.0.kind
+        self.0.internee == other.0.internee
     }
 }
 
-impl<'tcx> Eq for InternedInSet<'tcx, WithStableHash<PredicateS<'tcx>>> {}
+impl<'tcx, T: Eq> Eq for InternedInSet<'tcx, WithCachedTypeInfo<T>> {}
 
-impl<'tcx> Hash for InternedInSet<'tcx, WithStableHash<PredicateS<'tcx>>> {
+impl<'tcx, T: Hash> Hash for InternedInSet<'tcx, WithCachedTypeInfo<T>> {
     fn hash<H: Hasher>(&self, s: &mut H) {
         // The `Borrow` trait requires that `x.borrow().hash(s) == x.hash(s)`.
-        self.0.kind.hash(s)
+        self.0.internee.hash(s)
     }
 }