Directly use AttributeMap inside OwnerInfo.

Author: cjgillot

compiler/rustc_ast_lowering/src/lib.rs

@@ -476,6 +476,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let (nodes, parenting) =
             index::index_hir(self.sess, self.resolver.definitions(), node, &bodies);
         let nodes = hir::OwnerNodes { hash, node_hash, nodes, bodies };
+        let attrs = {
+            let mut hcx = self.resolver.create_stable_hashing_context();
+            let mut stable_hasher = StableHasher::new();
+            attrs.hash_stable(&mut hcx, &mut stable_hasher);
+            let hash = stable_hasher.finish();
+            hir::AttributeMap { map: attrs, hash }
+        };
 
         hir::OwnerInfo { nodes, parenting, attrs, trait_map }
     }

compiler/rustc_hir/src/hir.rs

@@ -672,6 +672,23 @@ pub struct ParentedNode<'tcx> {
     pub node: Node<'tcx>,
 }
 
+/// Attributes owner by a HIR owner.
+#[derive(Debug)]
+pub struct AttributeMap<'tcx> {
+    pub map: BTreeMap<ItemLocalId, &'tcx [Attribute]>,
+    pub hash: Fingerprint,
+}
+
+impl<'tcx> AttributeMap<'tcx> {
+    pub const EMPTY: &'static AttributeMap<'static> =
+        &AttributeMap { map: BTreeMap::new(), hash: Fingerprint::ZERO };
+
+    #[inline]
+    pub fn get(&self, id: ItemLocalId) -> &'tcx [Attribute] {
+        self.map.get(&id).copied().unwrap_or(&[])
+    }
+}
+
 #[derive(Debug)]
 pub struct OwnerNodes<'tcx> {
     /// Pre-computed hash of the full HIR.
@@ -691,8 +708,8 @@ pub struct OwnerInfo<'hir> {
     pub nodes: OwnerNodes<'hir>,
     /// Map from each nested owner to its parent's local id.
     pub parenting: FxHashMap<LocalDefId, ItemLocalId>,
-
-    pub attrs: BTreeMap<ItemLocalId, &'hir [Attribute]>,
+    /// Collected attributes of the HIR nodes.
+    pub attrs: AttributeMap<'hir>,
     /// Map indicating what traits are in scope for places where this
     /// is relevant; generated by resolve.
     pub trait_map: FxHashMap<ItemLocalId, Box<[TraitCandidate]>>,

compiler/rustc_hir/src/lib.rs

@@ -2,6 +2,7 @@
 //!
 //! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
 
+#![feature(const_btree_new)]
 #![feature(crate_visibility_modifier)]
 #![feature(in_band_lifetimes)]
 #![feature(once_cell)]

compiler/rustc_hir/src/stable_hash_impls.rs

@@ -1,8 +1,8 @@
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
 
 use crate::hir::{
-    BodyId, Expr, ForeignItem, ForeignItemId, ImplItem, ImplItemId, Item, ItemId, Mod, OwnerNodes,
-    TraitItem, TraitItemId, Ty, VisibilityKind,
+    AttributeMap, BodyId, Expr, ForeignItem, ForeignItemId, ImplItem, ImplItemId, Item, ItemId,
+    Mod, OwnerNodes, TraitItem, TraitItemId, Ty, VisibilityKind,
 };
 use crate::hir_id::{HirId, ItemLocalId};
 use rustc_span::def_id::DefPathHash;
@@ -218,3 +218,12 @@ impl<HirCtx: crate::HashStableContext> HashStable<HirCtx> for OwnerNodes<'tcx> {
         hash.hash_stable(hcx, hasher);
     }
 }
+
+impl<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);
+    }
+}

compiler/rustc_middle/src/hir/map/mod.rs

@@ -580,7 +580,7 @@ impl<'hir> Map<'hir> {
         let krate = self.krate();
         for (owner, info) in krate.owners.iter_enumerated() {
             if let Some(info) = info {
-                for (&local_id, attrs) in info.attrs.iter() {
+                for (&local_id, attrs) in info.attrs.map.iter() {
                     let id = HirId { owner, local_id };
                     for a in *attrs {
                         visitor.visit_attribute(id, a)

compiler/rustc_middle/src/hir/mod.rs

@@ -8,14 +8,12 @@ pub mod place;
 
 use crate::ty::query::Providers;
 use crate::ty::TyCtxt;
-use rustc_ast::Attribute;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::*;
 use rustc_query_system::ich::StableHashingContext;
 use rustc_span::DUMMY_SP;
-use std::collections::BTreeMap;
 
 /// Top-level HIR node for current owner. This only contains the node for which
 /// `HirId::local_id == 0`, and excludes bodies.
@@ -36,24 +34,6 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Owner<'tcx> {
     }
 }
 
-/// Attributes owner by a HIR owner.
-#[derive(Copy, Clone, Debug, HashStable)]
-pub struct AttributeMap<'tcx> {
-    map: &'tcx BTreeMap<ItemLocalId, &'tcx [Attribute]>,
-}
-
-impl<'tcx> AttributeMap<'tcx> {
-    fn new(owner_info: &'tcx Option<OwnerInfo<'tcx>>) -> AttributeMap<'tcx> {
-        const FALLBACK: &'static BTreeMap<ItemLocalId, &'static [Attribute]> = &BTreeMap::new();
-        let map = owner_info.as_ref().map_or(FALLBACK, |info| &info.attrs);
-        AttributeMap { map }
-    }
-
-    fn get(&self, id: ItemLocalId) -> &'tcx [Attribute] {
-        self.map.get(&id).copied().unwrap_or(&[])
-    }
-}
-
 /// Gather the LocalDefId for each item-like within a module, including items contained within
 /// bodies.  The Ids are in visitor order.  This is used to partition a pass between modules.
 #[derive(Debug, HashStable)]
@@ -105,7 +85,8 @@ pub fn provide(providers: &mut Providers) {
         });
         parent
     };
-    providers.hir_attrs = |tcx, id| AttributeMap::new(&tcx.hir_crate(()).owners[id]);
+    providers.hir_attrs =
+        |tcx, id| tcx.hir_crate(()).owners[id].as_ref().map_or(AttributeMap::EMPTY, |o| &o.attrs);
     providers.source_span = |tcx, def_id| tcx.resolutions(()).definitions.def_span(def_id);
     providers.def_span = |tcx, def_id| tcx.hir().span_if_local(def_id).unwrap_or(DUMMY_SP);
     providers.fn_arg_names = |tcx, id| {

compiler/rustc_middle/src/lib.rs

@@ -30,7 +30,6 @@
 #![feature(bool_to_option)]
 #![feature(box_patterns)]
 #![feature(core_intrinsics)]
-#![feature(const_btree_new)]
 #![feature(discriminant_kind)]
 #![feature(exhaustive_patterns)]
 #![feature(if_let_guard)]

compiler/rustc_middle/src/query/mod.rs

@@ -77,7 +77,7 @@ rustc_queries! {
     ///
     /// This can be conveniently accessed by methods on `tcx.hir()`.
     /// Avoid calling this query directly.
-    query hir_attrs(key: LocalDefId) -> rustc_middle::hir::AttributeMap<'tcx> {
+    query hir_attrs(key: LocalDefId) -> &'tcx hir::AttributeMap<'tcx> {
         desc { |tcx| "HIR owner attributes in `{}`", tcx.def_path_str(key.to_def_id()) }
     }