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Rollup merge of #104898 - oli-obk:group_all_the_things, r=wesleywiser 

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

cc `@nnethercote`

this allows re-use of the type for Predicate without duplicating all the logic for the non-hash cached fields
This commit is contained in:
Matthias Krüger 2022-12-06 16:54:52 +01:00 committed by GitHub
parent b6852428a8 14a9cf2ba2
commit db416ea195
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
10 changed files with 182 additions and 254 deletions
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83
compiler/rustc_data_structures/src/intern.rs
View File

@ -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;

2
compiler/rustc_lint/src/pass_by_value.rs
View File

@ -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]`",

6
compiler/rustc_middle/src/arena.rs
View File

@ -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
@ -89,8 +91,8 @@ 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`,

2
compiler/rustc_middle/src/mir/interpret/allocation.rs
View File

@ -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

83
compiler/rustc_middle/src/ty/context.rs
View File

@ -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};
@ -68,6 +70,7 @@ 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;
@ -137,13 +140,13 @@ 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>>>,
@ -194,15 +197,12 @@ 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,
))
@ -246,16 +246,12 @@ 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,
))
@ -2104,7 +2100,7 @@ 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,
@ -2214,51 +2210,26 @@ 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, 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<TyS<'tcx>>> {
fn eq(&self, other: &InternedInSet<'tcx, WithStableHash<TyS<'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<TyS<'tcx>>> {}
impl<'tcx, T: Eq> Eq for InternedInSet<'tcx, WithCachedTypeInfo<T>> {}
impl<'tcx> Hash for InternedInSet<'tcx, WithStableHash<TyS<'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)
}
}
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> PartialEq for InternedInSet<'tcx, WithStableHash<PredicateS<'tcx>>> {
fn eq(&self, other: &InternedInSet<'tcx, WithStableHash<PredicateS<'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<PredicateS<'tcx>>> {}
impl<'tcx> Hash for InternedInSet<'tcx, WithStableHash<PredicateS<'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)
self.0.internee.hash(s)
}
}

127
compiler/rustc_middle/src/ty/mod.rs
View File

@ -9,6 +9,8 @@
//!
//! ["The `ty` module: representing types"]: https://rustc-dev-guide.rust-lang.org/ty.html
#![allow(rustc::usage_of_ty_tykind)]
pub use self::fold::{FallibleTypeFolder, TypeFoldable, TypeFolder, TypeSuperFoldable};
pub use self::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
pub use self::AssocItemContainer::*;
@ -32,7 +34,7 @@ use rustc_ast::node_id::NodeMap;
use rustc_attr as attr;
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
use rustc_data_structures::intern::{Interned, WithStableHash};
use rustc_data_structures::intern::Interned;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::tagged_ptr::CopyTaggedPtr;
use rustc_hir as hir;
@ -50,6 +52,7 @@ use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::{ExpnId, Span};
use rustc_target::abi::{Align, Integer, IntegerType, VariantIdx};
pub use rustc_target::abi::{ReprFlags, ReprOptions};
use rustc_type_ir::WithCachedTypeInfo;
pub use subst::*;
pub use vtable::*;
@ -445,86 +448,22 @@ pub struct CReaderCacheKey {
pub pos: usize,
}
/// Represents a type.
///
/// IMPORTANT:
/// - This is a very "dumb" struct (with no derives and no `impls`).
/// - Values of this type are always interned and thus unique, and are stored
/// as an `Interned<TyS>`.
/// - `Ty` (which contains a reference to a `Interned<TyS>`) or `Interned<TyS>`
/// should be used everywhere instead of `TyS`. In particular, `Ty` has most
/// of the relevant methods.
#[derive(PartialEq, Eq, PartialOrd, Ord)]
#[allow(rustc::usage_of_ty_tykind)]
pub(crate) struct TyS<'tcx> {
/// This field shouldn't be used directly and may be removed in the future.
/// Use `Ty::kind()` instead.
kind: TyKind<'tcx>,
/// This field provides fast access to information that is also contained
/// in `kind`.
///
/// This field shouldn't be used directly and may be removed in the future.
/// Use `Ty::flags()` instead.
flags: TypeFlags,
/// This field provides fast access to information that is also contained
/// in `kind`.
///
/// This is a kind of confusing thing: it stores the smallest
/// binder such that
///
/// (a) the binder itself captures nothing but
/// (b) all the late-bound things within the type are captured
/// by some sub-binder.
///
/// So, for a type without any late-bound things, like `u32`, this
/// will be *innermost*, because that is the innermost binder that
/// captures nothing. But for a type `&'D u32`, where `'D` is a
/// late-bound region with De Bruijn index `D`, this would be `D + 1`
/// -- the binder itself does not capture `D`, but `D` is captured
/// by an inner binder.
///
/// We call this concept an "exclusive" binder `D` because all
/// De Bruijn indices within the type are contained within `0..D`
/// (exclusive).
outer_exclusive_binder: ty::DebruijnIndex,
}
/// Use this rather than `TyS`, whenever possible.
/// Use this rather than `TyKind`, whenever possible.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable)]
#[rustc_diagnostic_item = "Ty"]
#[rustc_pass_by_value]
pub struct Ty<'tcx>(Interned<'tcx, WithStableHash<TyS<'tcx>>>);
pub struct Ty<'tcx>(Interned<'tcx, WithCachedTypeInfo<TyKind<'tcx>>>);
impl<'tcx> TyCtxt<'tcx> {
/// A "bool" type used in rustc_mir_transform unit tests when we
/// have not spun up a TyCtxt.
pub const BOOL_TY_FOR_UNIT_TESTING: Ty<'tcx> = Ty(Interned::new_unchecked(&WithStableHash {
internee: TyS {
kind: ty::Bool,
pub const BOOL_TY_FOR_UNIT_TESTING: Ty<'tcx> =
Ty(Interned::new_unchecked(&WithCachedTypeInfo {
internee: ty::Bool,
stable_hash: Fingerprint::ZERO,
flags: TypeFlags::empty(),
outer_exclusive_binder: DebruijnIndex::from_usize(0),
},
stable_hash: Fingerprint::ZERO,
}));
}
impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TyS<'tcx> {
#[inline]
fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
let TyS {
kind,
// The other fields just provide fast access to information that is
// also contained in `kind`, so no need to hash them.
flags: _,
outer_exclusive_binder: _,
} = self;
kind.hash_stable(hcx, hasher)
}
}));
}
impl ty::EarlyBoundRegion {
@ -535,28 +474,18 @@ impl ty::EarlyBoundRegion {
}
}
/// Represents a predicate.
///
/// See comments on `TyS`, which apply here too (albeit for
/// `PredicateS`/`Predicate` rather than `TyS`/`Ty`).
#[derive(Debug)]
pub(crate) struct PredicateS<'tcx> {
kind: Binder<'tcx, PredicateKind<'tcx>>,
flags: TypeFlags,
/// See the comment for the corresponding field of [TyS].
outer_exclusive_binder: ty::DebruijnIndex,
}
/// Use this rather than `PredicateS`, whenever possible.
/// Use this rather than `PredicateKind`, whenever possible.
#[derive(Clone, Copy, PartialEq, Eq, Hash, HashStable)]
#[rustc_pass_by_value]
pub struct Predicate<'tcx>(Interned<'tcx, WithStableHash<PredicateS<'tcx>>>);
pub struct Predicate<'tcx>(
Interned<'tcx, WithCachedTypeInfo<ty::Binder<'tcx, PredicateKind<'tcx>>>>,
);
impl<'tcx> Predicate<'tcx> {
/// Gets the inner `Binder<'tcx, PredicateKind<'tcx>>`.
#[inline]
pub fn kind(self) -> Binder<'tcx, PredicateKind<'tcx>> {
self.0.kind
self.0.internee
}
#[inline(always)]
@ -631,21 +560,6 @@ impl<'tcx> Predicate<'tcx> {
}
}
impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for PredicateS<'tcx> {
fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
let PredicateS {
ref kind,
// The other fields just provide fast access to information that is
// also contained in `kind`, so no need to hash them.
flags: _,
outer_exclusive_binder: _,
} = self;
kind.hash_stable(hcx, hasher);
}
}
impl rustc_errors::IntoDiagnosticArg for Predicate<'_> {
fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
rustc_errors::DiagnosticArgValue::Str(std::borrow::Cow::Owned(self.to_string()))
@ -1028,7 +942,7 @@ impl<'tcx> Term<'tcx> {
unsafe {
match ptr & TAG_MASK {
TYPE_TAG => TermKind::Ty(Ty(Interned::new_unchecked(
&*((ptr & !TAG_MASK) as *const WithStableHash<ty::TyS<'tcx>>),
&*((ptr & !TAG_MASK) as *const WithCachedTypeInfo<ty::TyKind<'tcx>>),
))),
CONST_TAG => TermKind::Const(ty::Const(Interned::new_unchecked(
&*((ptr & !TAG_MASK) as *const ty::ConstS<'tcx>),
@ -1072,7 +986,7 @@ impl<'tcx> TermKind<'tcx> {
TermKind::Ty(ty) => {
// Ensure we can use the tag bits.
assert_eq!(mem::align_of_val(&*ty.0.0) & TAG_MASK, 0);
(TYPE_TAG, ty.0.0 as *const WithStableHash<ty::TyS<'tcx>> as usize)
(TYPE_TAG, ty.0.0 as *const WithCachedTypeInfo<ty::TyKind<'tcx>> as usize)
}
TermKind::Const(ct) => {
// Ensure we can use the tag bits.
@ -2692,8 +2606,7 @@ mod size_asserts {
use super::*;
use rustc_data_structures::static_assert_size;
// tidy-alphabetical-start
static_assert_size!(PredicateS<'_>, 48);
static_assert_size!(TyS<'_>, 40);
static_assert_size!(WithStableHash<TyS<'_>>, 56);
static_assert_size!(PredicateKind<'_>, 32);
static_assert_size!(WithCachedTypeInfo<TyKind<'_>>, 56);
// tidy-alphabetical-end
}

2
compiler/rustc_middle/src/ty/sty.rs
View File

@ -1611,7 +1611,7 @@ impl<'tcx> Region<'tcx> {
impl<'tcx> Ty<'tcx> {
#[inline(always)]
pub fn kind(self) -> &'tcx TyKind<'tcx> {
&self.0.0.kind
&self.0.0
}
#[inline(always)]

7
compiler/rustc_middle/src/ty/subst.rs
View File

@ -6,10 +6,11 @@ use crate::ty::sty::{ClosureSubsts, GeneratorSubsts, InlineConstSubsts};
use crate::ty::visit::{TypeVisitable, TypeVisitor};
use crate::ty::{self, Lift, List, ParamConst, Ty, TyCtxt};
use rustc_data_structures::intern::{Interned, WithStableHash};
use rustc_data_structures::intern::Interned;
use rustc_hir::def_id::DefId;
use rustc_macros::HashStable;
use rustc_serialize::{self, Decodable, Encodable};
use rustc_type_ir::WithCachedTypeInfo;
use smallvec::SmallVec;
use core::intrinsics;
@ -84,7 +85,7 @@ impl<'tcx> GenericArgKind<'tcx> {
GenericArgKind::Type(ty) => {
// Ensure we can use the tag bits.
assert_eq!(mem::align_of_val(&*ty.0.0) & TAG_MASK, 0);
(TYPE_TAG, ty.0.0 as *const WithStableHash<ty::TyS<'tcx>> as usize)
(TYPE_TAG, ty.0.0 as *const WithCachedTypeInfo<ty::TyKind<'tcx>> as usize)
}
GenericArgKind::Const(ct) => {
// Ensure we can use the tag bits.
@ -162,7 +163,7 @@ impl<'tcx> GenericArg<'tcx> {
&*((ptr & !TAG_MASK) as *const ty::RegionKind<'tcx>),
))),
TYPE_TAG => GenericArgKind::Type(Ty(Interned::new_unchecked(
&*((ptr & !TAG_MASK) as *const WithStableHash<ty::TyS<'tcx>>),
&*((ptr & !TAG_MASK) as *const WithCachedTypeInfo<ty::TyKind<'tcx>>),
))),
CONST_TAG => GenericArgKind::Const(ty::Const(Interned::new_unchecked(
&*((ptr & !TAG_MASK) as *const ty::ConstS<'tcx>),

2
compiler/rustc_type_ir/src/lib.rs
View File

@ -19,9 +19,11 @@ use std::mem::discriminant;
pub mod codec;
pub mod sty;
pub mod ty_info;
pub use codec::*;
pub use sty::*;
pub use ty_info::*;
/// Needed so we can use #[derive(HashStable_Generic)]
pub trait HashStableContext {}

122
compiler/rustc_type_ir/src/ty_info.rs Normal file
View File

@ -0,0 +1,122 @@
use std::{
cmp::Ordering,
hash::{Hash, Hasher},
ops::Deref,
};
use rustc_data_structures::{
fingerprint::Fingerprint,
stable_hasher::{HashStable, StableHasher},
};
use crate::{DebruijnIndex, TypeFlags};
/// A helper type that you can wrap round your own type in order to automatically
/// cache the stable hash, type flags and debruijn index on creation and
/// not recompute it whenever the information is needed.
/// 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 WithCachedTypeInfo<T> {
pub internee: T,
pub stable_hash: Fingerprint,
/// This field provides fast access to information that is also contained
/// in `kind`.
///
/// This field shouldn't be used directly and may be removed in the future.
/// Use `Ty::flags()` instead.
pub flags: TypeFlags,
/// This field provides fast access to information that is also contained
/// in `kind`.
///
/// This is a kind of confusing thing: it stores the smallest
/// binder such that
///
/// (a) the binder itself captures nothing but
/// (b) all the late-bound things within the type are captured
/// by some sub-binder.
///
/// So, for a type without any late-bound things, like `u32`, this
/// will be *innermost*, because that is the innermost binder that
/// captures nothing. But for a type `&'D u32`, where `'D` is a
/// late-bound region with De Bruijn index `D`, this would be `D + 1`
/// -- the binder itself does not capture `D`, but `D` is captured
/// by an inner binder.
///
/// We call this concept an "exclusive" binder `D` because all
/// De Bruijn indices within the type are contained within `0..D`
/// (exclusive).
pub outer_exclusive_binder: DebruijnIndex,
}
impl<T: PartialEq> PartialEq for WithCachedTypeInfo<T> {
#[inline]
fn eq(&self, other: &Self) -> bool {
self.internee.eq(&other.internee)
}
}
impl<T: Eq> Eq for WithCachedTypeInfo<T> {}
impl<T: Ord> PartialOrd for WithCachedTypeInfo<T> {
fn partial_cmp(&self, other: &WithCachedTypeInfo<T>) -> Option<Ordering> {
Some(self.internee.cmp(&other.internee))
}
}
impl<T: Ord> Ord for WithCachedTypeInfo<T> {
fn cmp(&self, other: &WithCachedTypeInfo<T>) -> Ordering {
self.internee.cmp(&other.internee)
}
}
impl<T> Deref for WithCachedTypeInfo<T> {
type Target = T;
#[inline]
fn deref(&self) -> &T {
&self.internee
}
}
impl<T: Hash> Hash for WithCachedTypeInfo<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 WithCachedTypeInfo<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);
}
}
}