make EII iteration faster

compiler/rustc_ast_lowering/src/item.rs

@@ -227,6 +227,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
             vis_span,
             span: self.lower_span(i.span),
             has_delayed_lints: !self.delayed_lints.is_empty(),
+            eii: find_attr!(
+                attrs,
+                AttributeKind::EiiImpls(..) | AttributeKind::EiiExternTarget(..)
+            ),
         };
         self.arena.alloc(item)
     }
@@ -670,6 +674,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             vis_span,
                             span: this.lower_span(use_tree.span),
                             has_delayed_lints: !this.delayed_lints.is_empty(),
+                            eii: find_attr!(
+                                attrs,
+                                AttributeKind::EiiImpls(..) | AttributeKind::EiiExternTarget(..)
+                            ),
                         };
                         hir::OwnerNode::Item(this.arena.alloc(item))
                     });

compiler/rustc_hir/src/hir.rs

@@ -4164,6 +4164,9 @@ pub struct Item<'hir> {
     pub span: Span,
     pub vis_span: Span,
     pub has_delayed_lints: bool,
+    /// hint to speed up collection: true if the item is a static or function and has
+    /// either an `EiiImpls` or `EiiExternTarget` attribute
+    pub eii: bool,
 }
 
 impl<'hir> Item<'hir> {

compiler/rustc_hir/src/intravisit.rs

@@ -532,7 +532,7 @@ pub fn walk_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v Param<'v>) ->
 }
 
 pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item<'v>) -> V::Result {
-    let Item { owner_id: _, kind, span: _, vis_span: _, has_delayed_lints: _ } = item;
+    let Item { owner_id: _, kind, span: _, vis_span: _, has_delayed_lints: _, eii: _ } = item;
     try_visit!(visitor.visit_id(item.hir_id()));
     match *kind {
         ItemKind::ExternCrate(orig_name, ident) => {

compiler/rustc_metadata/src/eii.rs

@@ -24,8 +24,7 @@ pub(crate) fn collect<'tcx>(tcx: TyCtxt<'tcx>, LocalCrate: LocalCrate) -> EiiMap
     let mut eiis = EiiMap::default();
 
     // iterate over all items in the current crate
-    // FIXME(speed up)
-    for id in tcx.hir_crate_items(()).definitions() {
+    for id in tcx.hir_crate_items(()).eiis() {
         for i in
             find_attr!(tcx.get_all_attrs(id), AttributeKind::EiiImpls(e) => e).into_iter().flatten()
         {

compiler/rustc_middle/src/hir/map.rs

@@ -1224,6 +1224,7 @@ pub(super) fn hir_module_items(tcx: TyCtxt<'_>, module_id: LocalModDefId) -> Mod
         body_owners,
         opaques,
         nested_bodies,
+        eiis,
         ..
     } = collector;
     ModuleItems {
@@ -1237,6 +1238,7 @@ pub(super) fn hir_module_items(tcx: TyCtxt<'_>, module_id: LocalModDefId) -> Mod
         opaques: opaques.into_boxed_slice(),
         nested_bodies: nested_bodies.into_boxed_slice(),
         delayed_lint_items: Box::new([]),
+        eiis: eiis.into_boxed_slice(),
     }
 }
 
@@ -1259,6 +1261,7 @@ pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
         opaques,
         nested_bodies,
         mut delayed_lint_items,
+        eiis,
         ..
     } = collector;
 
@@ -1281,6 +1284,7 @@ pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
         opaques: opaques.into_boxed_slice(),
         nested_bodies: nested_bodies.into_boxed_slice(),
         delayed_lint_items: delayed_lint_items.into_boxed_slice(),
+        eiis: eiis.into_boxed_slice(),
     }
 }
 
@@ -1298,6 +1302,7 @@ struct ItemCollector<'tcx> {
     opaques: Vec<LocalDefId>,
     nested_bodies: Vec<LocalDefId>,
     delayed_lint_items: Vec<OwnerId>,
+    eiis: Vec<LocalDefId>,
 }
 
 impl<'tcx> ItemCollector<'tcx> {
@@ -1314,6 +1319,7 @@ impl<'tcx> ItemCollector<'tcx> {
             opaques: Vec::default(),
             nested_bodies: Vec::default(),
             delayed_lint_items: Vec::default(),
+            eiis: Vec::default(),
         }
     }
 }
@@ -1335,6 +1341,12 @@ impl<'hir> Visitor<'hir> for ItemCollector<'hir> {
             self.delayed_lint_items.push(item.item_id().owner_id);
         }
 
+        if let ItemKind::Static(..) | ItemKind::Fn { .. } | ItemKind::Macro(..) = &item.kind
+            && item.eii
+        {
+            self.eiis.push(item.owner_id.def_id)
+        }
+
         // Items that are modules are handled here instead of in visit_mod.
         if let ItemKind::Mod(_, module) = &item.kind {
             self.submodules.push(item.owner_id);

compiler/rustc_middle/src/hir/mod.rs

@@ -37,6 +37,9 @@ pub struct ModuleItems {
     nested_bodies: Box<[LocalDefId]>,
     // only filled with hir_crate_items, not with hir_module_items
     delayed_lint_items: Box<[OwnerId]>,
+
+    /// Statics and functions with an `EiiImpls` or `EiiExternTarget` attribute
+    eiis: Box<[LocalDefId]>,
 }
 
 impl ModuleItems {
@@ -58,6 +61,10 @@ impl ModuleItems {
         self.delayed_lint_items.iter().copied()
     }
 
+    pub fn eiis(&self) -> impl Iterator<Item = LocalDefId> {
+        self.eiis.iter().copied()
+    }
+
     /// Returns all items that are associated with some `impl` block (both inherent and trait impl
     /// blocks).
     pub fn impl_items(&self) -> impl Iterator<Item = ImplItemId> {