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::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 BodyId {
19    type KeyType = (DefPathHash, ItemLocalId);
20
21    #[inline]
22    fn to_stable_hash_key(&self, hcx: &HirCtx) -> (DefPathHash, ItemLocalId) {
23        let BodyId { hir_id } = *self;
24        hir_id.to_stable_hash_key(hcx)
25    }
26}
27
28impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ItemId {
29    type KeyType = DefPathHash;
30
31    #[inline]
32    fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
33        self.owner_id.def_id.to_stable_hash_key(hcx)
34    }
35}
36
37impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for TraitItemId {
38    type KeyType = DefPathHash;
39
40    #[inline]
41    fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
42        self.owner_id.def_id.to_stable_hash_key(hcx)
43    }
44}
45
46impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ImplItemId {
47    type KeyType = DefPathHash;
48
49    #[inline]
50    fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
51        self.owner_id.def_id.to_stable_hash_key(hcx)
52    }
53}
54
55impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ForeignItemId {
56    type KeyType = DefPathHash;
57
58    #[inline]
59    fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
60        self.owner_id.def_id.to_stable_hash_key(hcx)
61    }
62}
63
64// The following implementations of HashStable for `ItemId`, `TraitItemId`, and
65// `ImplItemId` deserve special attention. Normally we do not hash `NodeId`s within
66// the HIR, since they just signify a HIR nodes own path. But `ItemId` et al
67// are used when another item in the HIR is *referenced* and we certainly
68// want to pick up on a reference changing its target, so we hash the NodeIds
69// in "DefPath Mode".
70
71impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for OwnerNodes<'tcx> {
72    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
73        // We ignore the `nodes` and `bodies` fields since these refer to information included in
74        // `hash` which is hashed in the collector and used for the crate hash.
75        // `local_id_to_def_id` is also ignored because is dependent on the body, then just hashing
76        // the body satisfies the condition of two nodes being different have different
77        // `hash_stable` results.
78        let OwnerNodes { opt_hash_including_bodies, nodes: _, bodies: _ } = *self;
79        opt_hash_including_bodies.unwrap().hash_stable(hcx, hasher);
80    }
81}
82
83impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for DelayedLints {
84    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
85        let DelayedLints { opt_hash, .. } = *self;
86        opt_hash.unwrap().hash_stable(hcx, hasher);
87    }
88}
89
90impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for AttributeMap<'tcx> {
91    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
92        // We ignore the `map` since it refers to information included in `opt_hash` which is
93        // hashed in the collector and used for the crate hash.
94        let AttributeMap { opt_hash, define_opaque: _, map: _ } = *self;
95        opt_hash.unwrap().hash_stable(hcx, hasher);
96    }
97}
98
99impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Crate<'_> {
100    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
101        let Crate { owners: _, opt_hir_hash } = self;
102        opt_hir_hash.unwrap().hash_stable(hcx, hasher)
103    }
104}
105
106impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for HashIgnoredAttrId {
107    fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
108        hcx.hash_attr_id(self, hasher)
109    }
110}
rustc_hir/stable_hash_impls.rs

rustc_hir/
stable_hash_impls.rs
