rustc_hir/
stable_hash_impls.rs

1use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
2use rustc_span::def_id::DefPathHash;
3
4use crate::HashIgnoredAttrId;
5use crate::hir::{
6    AttributeMap, BodyId, Crate, ForeignItemId, ImplItemId, ItemId, OwnerNodes, TraitItemId,
7};
8use crate::hir_id::{HirId, ItemLocalId};
9use crate::lints::DelayedLints;
10
11/// Requirements for a `StableHashingContext` to be used in this crate.
12/// This is a hack to allow using the `HashStable_Generic` derive macro
13/// instead of implementing everything in `rustc_middle`.
14pub trait HashStableContext: rustc_ast::HashStableContext + rustc_abi::HashStableContext {
15    fn hash_attr_id(&mut self, id: &HashIgnoredAttrId, hasher: &mut StableHasher);
16}
17
18impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for HirId {
19    type KeyType = (DefPathHash, ItemLocalId);
20
21    #[inline]
22    fn to_stable_hash_key(&self, hcx: &HirCtx) -> (DefPathHash, ItemLocalId) {
23        let def_path_hash = self.owner.def_id.to_stable_hash_key(hcx);
24        (def_path_hash, self.local_id)
25    }
26}
27
28impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ItemLocalId {
29    type KeyType = ItemLocalId;
30
31    #[inline]
32    fn to_stable_hash_key(&self, _: &HirCtx) -> ItemLocalId {
33        *self
34    }
35}
36
37impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for BodyId {
38    type KeyType = (DefPathHash, ItemLocalId);
39
40    #[inline]
41    fn to_stable_hash_key(&self, hcx: &HirCtx) -> (DefPathHash, ItemLocalId) {
42        let BodyId { hir_id } = *self;
43        hir_id.to_stable_hash_key(hcx)
44    }
45}
46
47impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ItemId {
48    type KeyType = DefPathHash;
49
50    #[inline]
51    fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
52        self.owner_id.def_id.to_stable_hash_key(hcx)
53    }
54}
55
56impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for TraitItemId {
57    type KeyType = DefPathHash;
58
59    #[inline]
60    fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
61        self.owner_id.def_id.to_stable_hash_key(hcx)
62    }
63}
64
65impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ImplItemId {
66    type KeyType = DefPathHash;
67
68    #[inline]
69    fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
70        self.owner_id.def_id.to_stable_hash_key(hcx)
71    }
72}
73
74impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ForeignItemId {
75    type KeyType = DefPathHash;
76
77    #[inline]
78    fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
79        self.owner_id.def_id.to_stable_hash_key(hcx)
80    }
81}
82
83// The following implementations of HashStable for `ItemId`, `TraitItemId`, and
84// `ImplItemId` deserve special attention. Normally we do not hash `NodeId`s within
85// the HIR, since they just signify a HIR nodes own path. But `ItemId` et al
86// are used when another item in the HIR is *referenced* and we certainly
87// want to pick up on a reference changing its target, so we hash the NodeIds
88// in "DefPath Mode".
89
90impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for OwnerNodes<'tcx> {
91    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
92        // We ignore the `nodes` and `bodies` fields since these refer to information included in
93        // `hash` which is hashed in the collector and used for the crate hash.
94        // `local_id_to_def_id` is also ignored because is dependent on the body, then just hashing
95        // the body satisfies the condition of two nodes being different have different
96        // `hash_stable` results.
97        let OwnerNodes { opt_hash_including_bodies, nodes: _, bodies: _ } = *self;
98        opt_hash_including_bodies.unwrap().hash_stable(hcx, hasher);
99    }
100}
101
102impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for DelayedLints {
103    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
104        let DelayedLints { opt_hash, .. } = *self;
105        opt_hash.unwrap().hash_stable(hcx, hasher);
106    }
107}
108
109impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for AttributeMap<'tcx> {
110    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
111        // We ignore the `map` since it refers to information included in `opt_hash` which is
112        // hashed in the collector and used for the crate hash.
113        let AttributeMap { opt_hash, define_opaque: _, map: _ } = *self;
114        opt_hash.unwrap().hash_stable(hcx, hasher);
115    }
116}
117
118impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Crate<'_> {
119    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
120        let Crate { owners: _, opt_hir_hash } = self;
121        opt_hir_hash.unwrap().hash_stable(hcx, hasher)
122    }
123}
124
125impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for HashIgnoredAttrId {
126    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
127        hcx.hash_attr_id(self, hasher)
128    }
129}
rustc_hir/stable_hash_impls.rs

rustc_hir/
stable_hash_impls.rs
