Auto merge of #86180 - cjgillot:defmv, r=petrochenkov

Hash DefId in rustc_span.

This is mostly just moving code around. Changes are simplifications of unneeded callbacks from rustc_span to rustc_middle.

r? `@petrochenkov`

compiler/rustc_hir/src/stable_hash_impls.rs

@@ -5,7 +5,7 @@
     TraitItem, TraitItemId, Ty, VisibilityKind,
 };
 use crate::hir_id::{HirId, ItemLocalId};
-use rustc_span::def_id::{DefPathHash, LocalDefId};
+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
@@ -21,7 +21,6 @@ pub trait HashStableContext:
     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 local_def_path_hash(&self, def_id: LocalDefId) -> DefPathHash;
 }
 
 impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for HirId {
@@ -29,7 +28,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for HirId {
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> (DefPathHash, ItemLocalId) {
-        let def_path_hash = hcx.local_def_path_hash(self.owner);
+        let def_path_hash = self.owner.to_stable_hash_key(hcx);
         (def_path_hash, self.local_id)
     }
 }
@@ -39,7 +38,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ItemId {
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
-        hcx.local_def_path_hash(self.def_id)
+        self.def_id.to_stable_hash_key(hcx)
     }
 }
 
@@ -48,7 +47,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for TraitItemId {
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
-        hcx.local_def_path_hash(self.def_id)
+        self.def_id.to_stable_hash_key(hcx)
     }
 }
 
@@ -57,7 +56,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ImplItemId {
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
-        hcx.local_def_path_hash(self.def_id)
+        self.def_id.to_stable_hash_key(hcx)
     }
 }
 
@@ -66,7 +65,7 @@ impl<HirCtx: crate::HashStableContext> ToStableHashKey<HirCtx> for ForeignItemId
 
     #[inline]
     fn to_stable_hash_key(&self, hcx: &HirCtx) -> DefPathHash {
-        hcx.local_def_path_hash(self.def_id)
+        self.def_id.to_stable_hash_key(hcx)
     }
 }
 

compiler/rustc_middle/src/ich/hcx.rs

@@ -14,7 +14,6 @@
 use rustc_span::symbol::Symbol;
 use rustc_span::{BytePos, CachingSourceMapView, SourceFile, SpanData};
 
-use rustc_span::def_id::{CrateNum, CRATE_DEF_INDEX};
 use smallvec::SmallVec;
 use std::cmp::Ord;
 use std::thread::LocalKey;
@@ -227,15 +226,8 @@ fn hash_spans(&self) -> bool {
     }
 
     #[inline]
-    fn hash_crate_num(&mut self, cnum: CrateNum, hasher: &mut StableHasher) {
-        let hcx = self;
-        hcx.def_path_hash(DefId { krate: cnum, index: CRATE_DEF_INDEX }).hash_stable(hcx, hasher);
-    }
-
-    #[inline]
-    fn hash_def_id(&mut self, def_id: DefId, hasher: &mut StableHasher) {
-        let hcx = self;
-        hcx.def_path_hash(def_id).hash_stable(hcx, hasher);
+    fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
+        self.def_path_hash(def_id)
     }
 
     fn expn_id_cache() -> &'static LocalKey<rustc_span::ExpnIdCache> {

compiler/rustc_middle/src/ich/impls_hir.rs

@@ -6,7 +6,6 @@
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
 use rustc_hir as hir;
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX};
 use rustc_hir::definitions::DefPathHash;
 use smallvec::SmallVec;
 use std::mem;
@@ -113,46 +112,6 @@ fn hash_hir_item_like<F: FnOnce(&mut Self)>(&mut self, f: F) {
 
         self.node_id_hashing_mode = prev_hash_node_ids;
     }
-
-    #[inline]
-    fn local_def_path_hash(&self, def_id: LocalDefId) -> DefPathHash {
-        self.local_def_path_hash(def_id)
-    }
-}
-
-impl<'a> ToStableHashKey<StableHashingContext<'a>> for DefId {
-    type KeyType = DefPathHash;
-
-    #[inline]
-    fn to_stable_hash_key(&self, hcx: &StableHashingContext<'a>) -> DefPathHash {
-        hcx.def_path_hash(*self)
-    }
-}
-
-impl<'a> HashStable<StableHashingContext<'a>> for LocalDefId {
-    #[inline]
-    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
-        hcx.def_path_hash(self.to_def_id()).hash_stable(hcx, hasher);
-    }
-}
-
-impl<'a> ToStableHashKey<StableHashingContext<'a>> for LocalDefId {
-    type KeyType = DefPathHash;
-
-    #[inline]
-    fn to_stable_hash_key(&self, hcx: &StableHashingContext<'a>) -> DefPathHash {
-        hcx.def_path_hash(self.to_def_id())
-    }
-}
-
-impl<'a> ToStableHashKey<StableHashingContext<'a>> for CrateNum {
-    type KeyType = DefPathHash;
-
-    #[inline]
-    fn to_stable_hash_key(&self, hcx: &StableHashingContext<'a>) -> DefPathHash {
-        let def_id = DefId { krate: *self, index: CRATE_DEF_INDEX };
-        def_id.to_stable_hash_key(hcx)
-    }
 }
 
 impl<'a> ToStableHashKey<StableHashingContext<'a>> for hir::ItemLocalId {

compiler/rustc_span/src/def_id.rs

 use crate::crate_disambiguator::CrateDisambiguator;
 use crate::HashStableContext;
 use rustc_data_structures::fingerprint::Fingerprint;
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
 use rustc_data_structures::AtomicRef;
 use rustc_index::vec::Idx;
 use rustc_macros::HashStable_Generic;
@@ -308,13 +308,49 @@ fn decode(d: &mut D) -> Result<LocalDefId, D::Error> {
 rustc_data_structures::define_id_collections!(LocalDefIdMap, LocalDefIdSet, LocalDefId);
 
 impl<CTX: HashStableContext> HashStable<CTX> for DefId {
+    #[inline]
+    fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
+        self.to_stable_hash_key(hcx).hash_stable(hcx, hasher);
+    }
+}
+
+impl<CTX: HashStableContext> HashStable<CTX> for LocalDefId {
+    #[inline]
     fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
-        hcx.hash_def_id(*self, hasher)
+        self.to_stable_hash_key(hcx).hash_stable(hcx, hasher);
     }
 }
 
 impl<CTX: HashStableContext> HashStable<CTX> for CrateNum {
+    #[inline]
     fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
-        hcx.hash_crate_num(*self, hasher)
+        self.to_stable_hash_key(hcx).hash_stable(hcx, hasher);
+    }
+}
+
+impl<CTX: HashStableContext> ToStableHashKey<CTX> for DefId {
+    type KeyType = DefPathHash;
+
+    #[inline]
+    fn to_stable_hash_key(&self, hcx: &CTX) -> DefPathHash {
+        hcx.def_path_hash(*self)
+    }
+}
+
+impl<CTX: HashStableContext> ToStableHashKey<CTX> for LocalDefId {
+    type KeyType = DefPathHash;
+
+    #[inline]
+    fn to_stable_hash_key(&self, hcx: &CTX) -> DefPathHash {
+        hcx.def_path_hash(self.to_def_id())
+    }
+}
+
+impl<CTX: HashStableContext> ToStableHashKey<CTX> for CrateNum {
+    type KeyType = DefPathHash;
+
+    #[inline]
+    fn to_stable_hash_key(&self, hcx: &CTX) -> DefPathHash {
+        self.as_def_id().to_stable_hash_key(hcx)
     }
 }

compiler/rustc_span/src/hygiene.rs

@@ -29,7 +29,7 @@
 use crate::SESSION_GLOBALS;
 use crate::{BytePos, CachingSourceMapView, ExpnIdCache, SourceFile, Span, DUMMY_SP};
 
-use crate::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
+use crate::def_id::{CrateNum, DefId, DefPathHash, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
@@ -1330,9 +1330,12 @@ struct DummyHashStableContext<'a> {
     }
 
     impl<'a> crate::HashStableContext for DummyHashStableContext<'a> {
-        fn hash_def_id(&mut self, def_id: DefId, hasher: &mut StableHasher) {
-            def_id.krate.as_u32().hash_stable(self, hasher);
-            def_id.index.as_u32().hash_stable(self, hasher);
+        #[inline]
+        fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
+            DefPathHash(Fingerprint::new(
+                def_id.krate.as_u32().into(),
+                def_id.index.as_u32().into(),
+            ))
         }
 
         fn expn_id_cache() -> &'static LocalKey<ExpnIdCache> {
@@ -1345,9 +1348,6 @@ fn expn_id_cache() -> &'static LocalKey<ExpnIdCache> {
             &CACHE
         }
 
-        fn hash_crate_num(&mut self, krate: CrateNum, hasher: &mut StableHasher) {
-            krate.as_u32().hash_stable(self, hasher);
-        }
         fn hash_spans(&self) -> bool {
             true
         }

compiler/rustc_span/src/lib.rs

@@ -40,7 +40,7 @@
 use hygiene::Transparency;
 pub use hygiene::{DesugaringKind, ExpnData, ExpnId, ExpnKind, ForLoopLoc, MacroKind};
 pub mod def_id;
-use def_id::{CrateNum, DefId, LOCAL_CRATE};
+use def_id::{CrateNum, DefId, DefPathHash, LOCAL_CRATE};
 pub mod lev_distance;
 mod span_encoding;
 pub use span_encoding::{Span, DUMMY_SP};
@@ -1928,13 +1928,12 @@ fn lookup_line(lines: &[BytePos], pos: BytePos) -> isize {
 /// This is a hack to allow using the [`HashStable_Generic`] derive macro
 /// instead of implementing everything in rustc_middle.
 pub trait HashStableContext {
-    fn hash_def_id(&mut self, _: DefId, hasher: &mut StableHasher);
+    fn def_path_hash(&self, def_id: DefId) -> DefPathHash;
     /// Obtains a cache for storing the `Fingerprint` of an `ExpnId`.
     /// This method allows us to have multiple `HashStableContext` implementations
     /// that hash things in a different way, without the results of one polluting
     /// the cache of the other.
     fn expn_id_cache() -> &'static LocalKey<ExpnIdCache>;
-    fn hash_crate_num(&mut self, _: CrateNum, hasher: &mut StableHasher);
     fn hash_spans(&self) -> bool;
     fn span_data_to_lines_and_cols(
         &mut self,