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rust/compiler/rustc_hir/src/stable_hash_impls.rs
Matthias Krüger 8611e292e4
Rollup merge of #93443 - spastorino:add-stable-hash-impl-doc, r=cjgillot
Add comment on stable_hash_impl for OwnerNodes

r? `@cjgillot`

cc `@oli-obk`

`@bors` rollup=always
2022-02-11 07:48:03 +01:00

243 lines
8.8 KiB
Rust

use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
use crate::hir::{
AttributeMap, BodyId, Crate, Expr, ForeignItem, ForeignItemId, ImplItem, ImplItemId, Item,
ItemId, OwnerNodes, TraitCandidate, TraitItem, TraitItemId, Ty, VisibilityKind,
};
use crate::hir_id::{HirId, ItemLocalId};
use rustc_span::def_id::DefPathHash;
/// Requirements for a `StableHashingContext` to be used in this crate.
/// This is a hack to allow using the `HashStable_Generic` derive macro
/// instead of implementing everything in `rustc_middle`.
pub trait HashStableContext:
rustc_ast::HashStableContext + rustc_target::HashStableContext
{
fn hash_hir_id(&mut self, _: HirId, hasher: &mut StableHasher);
fn hash_body_id(&mut self, _: BodyId, hasher: &mut StableHasher);
fn hash_reference_to_item(&mut self, _: HirId, hasher: &mut StableHasher);
fn hash_hir_expr(&mut self, _: &Expr<'_>, hasher: &mut StableHasher);
fn hash_hir_ty(&mut self, _: &Ty<'_>, hasher: &mut StableHasher);
fn hash_hir_visibility_kind(&mut self, _: &VisibilityKind<'_>, hasher: &mut StableHasher);
fn hash_hir_item_like<F: FnOnce(&mut Self)>(&mut self, f: F);
fn hash_hir_trait_candidate(&mut self, _: &TraitCandidate, hasher: &mut StableHasher);
}
impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for HirId {
type KeyType = (DefPathHash, ItemLocalId);
#[inline]
fn to_stable_hash_key(&self, hcx: &HirCtx) -> (DefPathHash, ItemLocalId) {
let def_path_hash = self.owner.to_stable_hash_key(hcx);
(def_path_hash, self.local_id)
}
}
impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ItemLocalId {
type KeyType = ItemLocalId;
#[inline]
fn to_stable_hash_key(&self, _: &HirCtx) -> ItemLocalId {
*self
}
}
impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for BodyId {
type KeyType = (DefPathHash, ItemLocalId);
#[inline]
fn to_stable_hash_key(&self, hcx: &HirCtx) -> (DefPathHash, ItemLocalId) {
let BodyId { hir_id } = *self;
hir_id.to_stable_hash_key(hcx)
}
}
impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ItemId {
type KeyType = DefPathHash;
#[inline]
fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
self.def_id.to_stable_hash_key(hcx)
}
}
impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for TraitItemId {
type KeyType = DefPathHash;
#[inline]
fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
self.def_id.to_stable_hash_key(hcx)
}
}
impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ImplItemId {
type KeyType = DefPathHash;
#[inline]
fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
self.def_id.to_stable_hash_key(hcx)
}
}
impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ForeignItemId {
type KeyType = DefPathHash;
#[inline]
fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
self.def_id.to_stable_hash_key(hcx)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for HirId {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_hir_id(*self, hasher)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for BodyId {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_body_id(*self, hasher)
}
}
// The following implementations of HashStable for `ItemId`, `TraitItemId`, and
// `ImplItemId` deserve special attention. Normally we do not hash `NodeId`s within
// the HIR, since they just signify a HIR nodes own path. But `ItemId` et al
// are used when another item in the HIR is *referenced* and we certainly
// want to pick up on a reference changing its target, so we hash the NodeIds
// in "DefPath Mode".
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for ItemId {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_reference_to_item(self.hir_id(), hasher)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for ForeignItemId {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_reference_to_item(self.hir_id(), hasher)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for ImplItemId {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_reference_to_item(self.hir_id(), hasher)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for TraitItemId {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_reference_to_item(self.hir_id(), hasher)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Expr<'_> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_hir_expr(self, hasher)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Ty<'_> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_hir_ty(self, hasher)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for VisibilityKind<'_> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_hir_visibility_kind(self, hasher)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for TraitItem<'_> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
let TraitItem { def_id: _, ident, ref generics, ref kind, span } = *self;
hcx.hash_hir_item_like(|hcx| {
ident.name.hash_stable(hcx, hasher);
generics.hash_stable(hcx, hasher);
kind.hash_stable(hcx, hasher);
span.hash_stable(hcx, hasher);
});
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for ImplItem<'_> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
let ImplItem { def_id: _, ident, ref vis, ref generics, ref kind, span } = *self;
hcx.hash_hir_item_like(|hcx| {
ident.name.hash_stable(hcx, hasher);
vis.hash_stable(hcx, hasher);
generics.hash_stable(hcx, hasher);
kind.hash_stable(hcx, hasher);
span.hash_stable(hcx, hasher);
});
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for ForeignItem<'_> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
let ForeignItem { def_id: _, ident, ref kind, span, ref vis } = *self;
hcx.hash_hir_item_like(|hcx| {
ident.name.hash_stable(hcx, hasher);
kind.hash_stable(hcx, hasher);
span.hash_stable(hcx, hasher);
vis.hash_stable(hcx, hasher);
});
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Item<'_> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
let Item { ident, def_id: _, ref kind, ref vis, span } = *self;
hcx.hash_hir_item_like(|hcx| {
ident.name.hash_stable(hcx, hasher);
kind.hash_stable(hcx, hasher);
vis.hash_stable(hcx, hasher);
span.hash_stable(hcx, hasher);
});
}
}
impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for OwnerNodes<'tcx> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
// We ignore the `nodes` and `bodies` fields since these refer to information included in
// `hash` which is hashed in the collector and used for the crate hash.
// `local_id_to_def_id` is also ignored because is dependent on the body, then just hashing
// the body satisfies the condition of two nodes being different have different
// `hash_stable` results.
let OwnerNodes {
hash_including_bodies,
hash_without_bodies: _,
nodes: _,
bodies: _,
local_id_to_def_id: _,
} = *self;
hash_including_bodies.hash_stable(hcx, hasher);
}
}
impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for AttributeMap<'tcx> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
// We ignore the `map` since it refers to information included in `hash` which is hashed in
// the collector and used for the crate hash.
let AttributeMap { hash, map: _ } = *self;
hash.hash_stable(hcx, hasher);
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Crate<'_> {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
let Crate { owners: _, hir_hash } = self;
hir_hash.hash_stable(hcx, hasher)
}
}
impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for TraitCandidate {
fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
hcx.hash_hir_trait_candidate(self, hasher)
}
}