compiler/rustc_middle/src/ty/impls_ty.rs

   1 //! This module contains `HashStable` implementations for various data types
   2 //! from `rustc_middle::ty` in no particular order.
   3
   4 use crate::middle::region;
   5 use crate::mir;
   6 use crate::ty;
   7 use rustc_data_structures::fingerprint::Fingerprint;
   8 use rustc_data_structures::fx::FxHashMap;
   9 use rustc_data_structures::stable_hasher::HashingControls;
  10 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
  11 use rustc_query_system::ich::StableHashingContext;
  12 use std::cell::RefCell;
  13 use std::mem;
  14
  15 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for &'tcx ty::List<T>
  16 where
  17     T: HashStable<StableHashingContext<'a>>,
  18 {
  19     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
  20         thread_local! {
  21             static CACHE: RefCell<FxHashMap<(usize, usize, HashingControls), Fingerprint>> =
  22                 RefCell::new(Default::default());
  23         }
  24
  25         let hash = CACHE.with(|cache| {
  26             let key = (self.as_ptr() as usize, self.len(), hcx.hashing_controls());
  27             if let Some(&hash) = cache.borrow().get(&key) {
  28                 return hash;
  29             }
  30
  31             let mut hasher = StableHasher::new();
  32             (&self[..]).hash_stable(hcx, &mut hasher);
  33
  34             let hash: Fingerprint = hasher.finish();
  35             cache.borrow_mut().insert(key, hash);
  36             hash
  37         });
  38
  39         hash.hash_stable(hcx, hasher);
  40     }
  41 }
  42
  43 impl<'a, 'tcx, T> ToStableHashKey<StableHashingContext<'a>> for &'tcx ty::List<T>
  44 where
  45     T: HashStable<StableHashingContext<'a>>,
  46 {
  47     type KeyType = Fingerprint;
  48
  49     #[inline]
  50     fn to_stable_hash_key(&self, hcx: &StableHashingContext<'a>) -> Fingerprint {
  51         let mut hasher = StableHasher::new();
  52         let mut hcx: StableHashingContext<'a> = hcx.clone();
  53         self.hash_stable(&mut hcx, &mut hasher);
  54         hasher.finish()
  55     }
  56 }
  57
  58 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::subst::GenericArg<'tcx> {
  59     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
  60         self.unpack().hash_stable(hcx, hasher);
  61     }
  62 }
  63
  64 impl<'a> HashStable<StableHashingContext<'a>> for ty::RegionKind {
  65     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
  66         mem::discriminant(self).hash_stable(hcx, hasher);
  67         match *self {
  68             ty::ReErased | ty::ReStatic => {
  69                 // No variant fields to hash for these ...
  70             }
  71             ty::ReEmpty(universe) => {
  72                 universe.hash_stable(hcx, hasher);
  73             }
  74             ty::ReLateBound(db, ty::BoundRegion { kind: ty::BrAnon(i), .. }) => {
  75                 db.hash_stable(hcx, hasher);
  76                 i.hash_stable(hcx, hasher);
  77             }
  78             ty::ReLateBound(db, ty::BoundRegion { kind: ty::BrNamed(def_id, name), .. }) => {
  79                 db.hash_stable(hcx, hasher);
  80                 def_id.hash_stable(hcx, hasher);
  81                 name.hash_stable(hcx, hasher);
  82             }
  83             ty::ReLateBound(db, ty::BoundRegion { kind: ty::BrEnv, .. }) => {
  84                 db.hash_stable(hcx, hasher);
  85             }
  86             ty::ReEarlyBound(ty::EarlyBoundRegion { def_id, index, name }) => {
  87                 def_id.hash_stable(hcx, hasher);
  88                 index.hash_stable(hcx, hasher);
  89                 name.hash_stable(hcx, hasher);
  90             }
  91             ty::ReFree(ref free_region) => {
  92                 free_region.hash_stable(hcx, hasher);
  93             }
  94             ty::RePlaceholder(p) => {
  95                 p.hash_stable(hcx, hasher);
  96             }
  97             ty::ReVar(..) => {
  98                 bug!("StableHasher: unexpected region {:?}", *self)
  99             }
 100         }
 101     }
 102 }
 103
 104 impl<'a> HashStable<StableHashingContext<'a>> for ty::RegionVid {
 105     #[inline]
 106     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
 107         self.index().hash_stable(hcx, hasher);
 108     }
 109 }
 110
 111 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::ConstVid<'tcx> {
 112     #[inline]
 113     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
 114         self.index.hash_stable(hcx, hasher);
 115     }
 116 }
 117
 118 impl<'tcx> HashStable<StableHashingContext<'tcx>> for ty::BoundVar {
 119     #[inline]
 120     fn hash_stable(&self, hcx: &mut StableHashingContext<'tcx>, hasher: &mut StableHasher) {
 121         self.index().hash_stable(hcx, hasher);
 122     }
 123 }
 124
 125 impl<'a, 'tcx, T> HashStable<StableHashingContext<'a>> for ty::Binder<'tcx, T>
 126 where
 127     T: HashStable<StableHashingContext<'a>>,
 128 {
 129     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
 130         self.as_ref().skip_binder().hash_stable(hcx, hasher);
 131         self.bound_vars().hash_stable(hcx, hasher);
 132     }
 133 }
 134
 135 // AllocIds get resolved to whatever they point to (to be stable)
 136 impl<'a> HashStable<StableHashingContext<'a>> for mir::interpret::AllocId {
 137     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
 138         ty::tls::with_opt(|tcx| {
 139             trace!("hashing {:?}", *self);
 140             let tcx = tcx.expect("can't hash AllocIds during hir lowering");
 141             tcx.get_global_alloc(*self).hash_stable(hcx, hasher);
 142         });
 143     }
 144 }
 145
 146 // `Relocations` with default type parameters is a sorted map.
 147 impl<'a, Tag> HashStable<StableHashingContext<'a>> for mir::interpret::Relocations<Tag>
 148 where
 149     Tag: HashStable<StableHashingContext<'a>>,
 150 {
 151     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
 152         self.len().hash_stable(hcx, hasher);
 153         for reloc in self.iter() {
 154             reloc.hash_stable(hcx, hasher);
 155         }
 156     }
 157 }
 158
 159 impl<'a> ToStableHashKey<StableHashingContext<'a>> for region::Scope {
 160     type KeyType = region::Scope;
 161
 162     #[inline]
 163     fn to_stable_hash_key(&self, _: &StableHashingContext<'a>) -> region::Scope {
 164         *self
 165     }
 166 }