Back-and-forth feed the hir_owner query

Author: oli-obk

compiler/rustc_ast_lowering/src/lib.rs

@@ -429,7 +429,7 @@ fn compute_hir_hash(
     })
 }
 
-pub fn lower_to_hir(tcx: TyCtxt<'_>, (): ()) -> hir::Crate<'_> {
+pub fn lower_to_hir(tcx: TyCtxt<'_>, (): ()) -> hir::Crate {
     let sess = tcx.sess;
     // Queries that borrow `resolver_for_lowering`.
     tcx.ensure_done().output_filenames(());
@@ -466,7 +466,12 @@ pub fn lower_to_hir(tcx: TyCtxt<'_>, (): ()) -> hir::Crate<'_> {
     // Don't hash unless necessary, because it's expensive.
     let opt_hir_hash =
         if tcx.needs_crate_hash() { Some(compute_hir_hash(tcx, &owners)) } else { None };
-    hir::Crate { owners, opt_hir_hash }
+
+    for (def_id, owner) in owners.drain_enumerated(..) {
+        tcx.super_duper_perf_hack_experiment(def_id).hir_owner(owner)
+    }
+
+    hir::Crate { opt_hir_hash }
 }
 
 #[derive(Copy, Clone, PartialEq, Debug)]

compiler/rustc_hir/src/hir.rs

@@ -1571,8 +1571,7 @@ impl<'tcx> MaybeOwner<'tcx> {
 ///
 /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
 #[derive(Debug)]
-pub struct Crate<'hir> {
-    pub owners: IndexVec<LocalDefId, MaybeOwner<'hir>>,
+pub struct Crate {
     // Only present when incr. comp. is enabled.
     pub opt_hir_hash: Option<Fingerprint>,
 }

compiler/rustc_hir/src/stable_hash_impls.rs

@@ -111,9 +111,9 @@ impl<'tcx, HirCtx: crate::HashStableContext> HashStable<HirCtx> for AttributeMap
     }
 }
 
-impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Crate<'_> {
+impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for Crate {
     fn hash_stable(&self, hcx: &mut HirCtx, hasher: &mut StableHasher) {
-        let Crate { owners: _, opt_hir_hash } = self;
+        let Crate { opt_hir_hash } = self;
         opt_hir_hash.unwrap().hash_stable(hcx, hasher)
     }
 }

compiler/rustc_middle/src/hir/mod.rs

@@ -181,14 +181,18 @@ pub fn provide(providers: &mut Providers) {
     providers.hir_crate_items = map::hir_crate_items;
     providers.crate_hash = map::crate_hash;
     providers.hir_module_items = map::hir_module_items;
-    providers.hir_owner =
-        |tcx, def_id| tcx.hir_crate(()).owners.get(def_id).copied().unwrap_or(MaybeOwner::Phantom);
-    providers.local_def_id_to_hir_id = |tcx, def_id| match tcx.hir_owner(def_id) {
-        MaybeOwner::Owner(_) => HirId::make_owner(def_id),
-        MaybeOwner::NonOwner(hir_id) => hir_id,
-        MaybeOwner::Phantom => bug!("No HirId for {:?}", def_id),
+    providers.local_def_id_to_hir_id = |tcx, def_id| {
+        tcx.ensure_ok().hir_crate(());
+        match tcx.hir_owner(def_id) {
+            MaybeOwner::Owner(_) => HirId::make_owner(def_id),
+            MaybeOwner::NonOwner(hir_id) => hir_id,
+            MaybeOwner::Phantom => bug!("No HirId for {:?}", def_id),
+        }
+    };
+    providers.opt_hir_owner_nodes = |tcx, id| {
+        tcx.ensure_ok().hir_crate(());
+        tcx.hir_owner(id).as_owner().map(|i| &i.nodes)
     };
-    providers.opt_hir_owner_nodes = |tcx, id| tcx.hir_owner(id).as_owner().map(|i| &i.nodes);
     providers.hir_owner_parent = |tcx, owner_id| {
         tcx.opt_local_parent(owner_id.def_id).map_or(CRATE_HIR_ID, |parent_def_id| {
             let parent_owner_id = tcx.local_def_id_to_hir_id(parent_def_id).owner;
@@ -204,8 +208,10 @@ pub fn provide(providers: &mut Providers) {
             }
         })
     };
-    providers.hir_attr_map =
-        |tcx, id| tcx.hir_owner(id.def_id).as_owner().map_or(AttributeMap::EMPTY, |o| &o.attrs);
+    providers.hir_attr_map = |tcx, id| {
+        tcx.ensure_ok().hir_crate(());
+        tcx.hir_owner(id.def_id).as_owner().map_or(AttributeMap::EMPTY, |o| &o.attrs)
+    };
     providers.def_span = |tcx, def_id| tcx.hir_span(tcx.local_def_id_to_hir_id(def_id));
     providers.def_ident_span = |tcx, def_id| {
         let hir_id = tcx.local_def_id_to_hir_id(def_id);

compiler/rustc_middle/src/query/mod.rs

@@ -166,7 +166,7 @@ rustc_queries! {
     /// query gives you access to all other items. To avoid this fate, do not
     /// call `tcx.hir_crate(())`; instead, prefer wrappers like
     /// [`TyCtxt::hir_visit_all_item_likes_in_crate`].
-    query hir_crate(key: ()) -> &'tcx Crate<'tcx> {
+    query hir_crate(key: ()) -> &'tcx Crate {
         arena_cache
         eval_always
         desc { "getting the crate HIR" }

compiler/rustc_middle/src/ty/context.rs

@@ -1272,6 +1272,11 @@ impl<'tcx> TyCtxt<'tcx> {
         TyCtxtFeed { tcx: self, key: () }
     }
 
+    pub fn super_duper_perf_hack_experiment(self, key: LocalDefId) -> TyCtxtFeed<'tcx, LocalDefId> {
+        self.dep_graph.assert_eval_always();
+        TyCtxtFeed { tcx: self, key }
+    }
+
     /// Only used in the resolver to register the `CRATE_DEF_ID` `DefId` and feed
     /// some queries for it. It will panic if used twice.
     pub fn create_local_crate_def_id(self, span: Span) -> TyCtxtFeed<'tcx, LocalDefId> {

compiler/rustc_query_system/src/dep_graph/graph.rs

@@ -200,6 +200,18 @@ impl<D: Deps> DepGraph<D> {
         }
     }
 
+    pub fn assert_eval_always(&self) {
+        if let Some(..) = self.data {
+            D::read_deps(|task_deps| {
+                assert_matches!(
+                    task_deps,
+                    TaskDepsRef::EvalAlways,
+                    "expected no task dependency tracking"
+                );
+            })
+        }
+    }
+
     pub fn with_ignore<OP, R>(&self, op: OP) -> R
     where
         OP: FnOnce() -> R,