Refactor HIR item-like traversal (part 1)

compiler/rustc_hir/src/target.rs

@@ -7,6 +7,7 @@
 use crate::hir;
 use crate::{Item, ItemKind, TraitItem, TraitItemKind};
 
+use crate::def::DefKind;
 use std::fmt::{self, Display};
 
 #[derive(Copy, Clone, PartialEq, Debug)]
@@ -130,6 +131,30 @@ impl Target {
         }
     }
 
+    // FIXME: For now, should only be used with def_kinds from ItemIds
+    pub fn from_def_kind(def_kind: DefKind) -> Target {
+        match def_kind {
+            DefKind::ExternCrate => Target::ExternCrate,
+            DefKind::Use => Target::Use,
+            DefKind::Static(..) => Target::Static,
+            DefKind::Const => Target::Const,
+            DefKind::Fn => Target::Fn,
+            DefKind::Macro(..) => Target::MacroDef,
+            DefKind::Mod => Target::Mod,
+            DefKind::ForeignMod => Target::ForeignMod,
+            DefKind::GlobalAsm => Target::GlobalAsm,
+            DefKind::TyAlias => Target::TyAlias,
+            DefKind::OpaqueTy => Target::OpaqueTy,
+            DefKind::Enum => Target::Enum,
+            DefKind::Struct => Target::Struct,
+            DefKind::Union => Target::Union,
+            DefKind::Trait => Target::Trait,
+            DefKind::TraitAlias => Target::TraitAlias,
+            DefKind::Impl => Target::Impl,
+            _ => panic!("impossible case reached"),
+        }
+    }
+
     pub fn from_trait_item(trait_item: &TraitItem<'_>) -> Target {
         match trait_item.kind {
             TraitItemKind::Const(..) => Target::AssocConst,

compiler/rustc_incremental/src/persist/dirty_clean.rs

@@ -24,7 +24,6 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit;
-use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::Node as HirNode;
 use rustc_hir::{ImplItemKind, ItemKind as HirItem, TraitItemKind};
 use rustc_middle::dep_graph::{label_strs, DepNode, DepNodeExt};
@@ -147,7 +146,24 @@ pub fn check_dirty_clean_annotations(tcx: TyCtxt<'_>) {
 
     tcx.dep_graph.with_ignore(|| {
         let mut dirty_clean_visitor = DirtyCleanVisitor { tcx, checked_attrs: Default::default() };
-        tcx.hir().visit_all_item_likes(&mut dirty_clean_visitor);
+
+        let crate_items = tcx.hir_crate_items(());
+
+        for id in crate_items.items() {
+            dirty_clean_visitor.check_item(id.def_id);
+        }
+
+        for id in crate_items.trait_items() {
+            dirty_clean_visitor.check_item(id.def_id);
+        }
+
+        for id in crate_items.impl_items() {
+            dirty_clean_visitor.check_item(id.def_id);
+        }
+
+        for id in crate_items.foreign_items() {
+            dirty_clean_visitor.check_item(id.def_id);
+        }
 
         let mut all_attrs = FindAllAttrs { tcx, found_attrs: vec![] };
         tcx.hir().walk_attributes(&mut all_attrs);
@@ -365,7 +381,8 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
         }
     }
 
-    fn check_item(&mut self, item_id: LocalDefId, item_span: Span) {
+    fn check_item(&mut self, item_id: LocalDefId) {
+        let item_span = self.tcx.def_span(item_id.to_def_id());
         let def_path_hash = self.tcx.def_path_hash(item_id.to_def_id());
         for attr in self.tcx.get_attrs(item_id.to_def_id()).iter() {
             let Some(assertion) = self.assertion_maybe(item_id, attr) else {
@@ -388,24 +405,6 @@ impl<'tcx> DirtyCleanVisitor<'tcx> {
     }
 }
 
-impl<'tcx> ItemLikeVisitor<'tcx> for DirtyCleanVisitor<'tcx> {
-    fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
-        self.check_item(item.def_id, item.span);
-    }
-
-    fn visit_trait_item(&mut self, item: &hir::TraitItem<'_>) {
-        self.check_item(item.def_id, item.span);
-    }
-
-    fn visit_impl_item(&mut self, item: &hir::ImplItem<'_>) {
-        self.check_item(item.def_id, item.span);
-    }
-
-    fn visit_foreign_item(&mut self, item: &hir::ForeignItem<'_>) {
-        self.check_item(item.def_id, item.span);
-    }
-}
-
 /// Given a `#[rustc_clean]` attribute, scan for a `cfg="foo"` attribute and check whether we have
 /// a cfg flag called `foo`.
 fn check_config(tcx: TyCtxt<'_>, attr: &Attribute) -> bool {

compiler/rustc_interface/src/proc_macro_decls.rs

@@ -1,35 +1,25 @@
 use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
-use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::symbol::sym;
 
 fn proc_macro_decls_static(tcx: TyCtxt<'_>, (): ()) -> Option<LocalDefId> {
     let mut finder = Finder { tcx, decls: None };
-    tcx.hir().visit_all_item_likes(&mut finder);
 
-    finder.decls.map(|id| tcx.hir().local_def_id(id))
-}
-
-struct Finder<'tcx> {
-    tcx: TyCtxt<'tcx>,
-    decls: Option<hir::HirId>,
-}
-
-impl<'v> ItemLikeVisitor<'v> for Finder<'_> {
-    fn visit_item(&mut self, item: &hir::Item<'_>) {
-        let attrs = self.tcx.hir().attrs(item.hir_id());
-        if self.tcx.sess.contains_name(attrs, sym::rustc_proc_macro_decls) {
-            self.decls = Some(item.hir_id());
+    for id in tcx.hir().items() {
+        let attrs = finder.tcx.hir().attrs(id.hir_id());
+        if finder.tcx.sess.contains_name(attrs, sym::rustc_proc_macro_decls) {
+            finder.decls = Some(id.def_id);
         }
     }
 
-    fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem<'_>) {}
-
-    fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem<'_>) {}
+    finder.decls
+}
 
-    fn visit_foreign_item(&mut self, _foreign_item: &hir::ForeignItem<'_>) {}
+struct Finder<'tcx> {
+    tcx: TyCtxt<'tcx>,
+    decls: Option<hir::def_id::LocalDefId>,
 }
 
 pub(crate) fn provide(providers: &mut Providers) {

compiler/rustc_metadata/src/foreign_modules.rs

@@ -1,29 +1,19 @@
 use rustc_hir as hir;
-use rustc_hir::itemlikevisit::ItemLikeVisitor;
+use rustc_hir::def::DefKind;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::cstore::ForeignModule;
 
 crate fn collect(tcx: TyCtxt<'_>) -> Vec<ForeignModule> {
-    let mut collector = Collector { modules: Vec::new() };
-    tcx.hir().visit_all_item_likes(&mut collector);
-    collector.modules
-}
-
-struct Collector {
-    modules: Vec<ForeignModule>,
-}
-
-impl<'tcx> ItemLikeVisitor<'tcx> for Collector {
-    fn visit_item(&mut self, it: &'tcx hir::Item<'tcx>) {
-        let hir::ItemKind::ForeignMod { items, .. } = it.kind else {
-            return;
-        };
-
-        let foreign_items = items.iter().map(|it| it.id.def_id.to_def_id()).collect();
-        self.modules.push(ForeignModule { foreign_items, def_id: it.def_id.to_def_id() });
+    let mut modules = Vec::new();
+    for id in tcx.hir().items() {
+        if !matches!(tcx.hir().def_kind(id.def_id), DefKind::ForeignMod) {
+            continue;
+        }
+        let item = tcx.hir().item(id);
+        if let hir::ItemKind::ForeignMod { items, .. } = item.kind {
+            let foreign_items = items.iter().map(|it| it.id.def_id.to_def_id()).collect();
+            modules.push(ForeignModule { foreign_items, def_id: id.def_id.to_def_id() });
+        }
     }
-
-    fn visit_trait_item(&mut self, _it: &'tcx hir::TraitItem<'tcx>) {}
-    fn visit_impl_item(&mut self, _it: &'tcx hir::ImplItem<'tcx>) {}
-    fn visit_foreign_item(&mut self, _it: &'tcx hir::ForeignItem<'tcx>) {}
+    modules
 }

compiler/rustc_metadata/src/native_libs.rs

@@ -3,7 +3,7 @@ use rustc_attr as attr;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
-use rustc_hir::itemlikevisit::ItemLikeVisitor;
+use rustc_hir::def::DefKind;
 use rustc_middle::ty::{List, ParamEnv, ParamEnvAnd, Ty, TyCtxt};
 use rustc_session::cstore::{DllCallingConvention, DllImport, NativeLib};
 use rustc_session::parse::feature_err;
@@ -15,7 +15,9 @@ use rustc_target::spec::abi::Abi;
 
 crate fn collect(tcx: TyCtxt<'_>) -> Vec<NativeLib> {
     let mut collector = Collector { tcx, libs: Vec::new() };
-    tcx.hir().visit_all_item_likes(&mut collector);
+    for id in tcx.hir().items() {
+        collector.process_item(id);
+    }
     collector.process_command_line();
     collector.libs
 }
@@ -32,8 +34,13 @@ struct Collector<'tcx> {
     libs: Vec<NativeLib>,
 }
 
-impl<'tcx> ItemLikeVisitor<'tcx> for Collector<'tcx> {
-    fn visit_item(&mut self, it: &'tcx hir::Item<'tcx>) {
+impl<'tcx> Collector<'tcx> {
+    fn process_item(&mut self, id: rustc_hir::ItemId) {
+        if !matches!(self.tcx.hir().def_kind(id.def_id), DefKind::ForeignMod) {
+            return;
+        }
+
+        let it = self.tcx.hir().item(id);
         let hir::ItemKind::ForeignMod { abi, items: foreign_mod_items } = it.kind else {
             return;
         };
@@ -252,12 +259,6 @@ impl<'tcx> ItemLikeVisitor<'tcx> for Collector<'tcx> {
         }
     }
 
-    fn visit_trait_item(&mut self, _it: &'tcx hir::TraitItem<'tcx>) {}
-    fn visit_impl_item(&mut self, _it: &'tcx hir::ImplItem<'tcx>) {}
-    fn visit_foreign_item(&mut self, _it: &'tcx hir::ForeignItem<'tcx>) {}
-}
-
-impl Collector<'_> {
     fn register_native_lib(&mut self, span: Option<Span>, lib: NativeLib) {
         if lib.name.as_ref().map_or(false, |&s| s == kw::Empty) {
             match span {

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1783,10 +1783,27 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         debug!("EncodeContext::encode_traits_and_impls()");
         empty_proc_macro!(self);
         let tcx = self.tcx;
-        let mut visitor = ImplsVisitor { tcx, impls: FxHashMap::default() };
-        tcx.hir().visit_all_item_likes(&mut visitor);
+        let mut fx_hash_map: FxHashMap<DefId, Vec<(DefIndex, Option<SimplifiedType>)>> =
+            FxHashMap::default();
 
-        let mut all_impls: Vec<_> = visitor.impls.into_iter().collect();
+        for id in tcx.hir().items() {
+            if matches!(tcx.hir().def_kind(id.def_id), DefKind::Impl) {
+                if let Some(trait_ref) = tcx.impl_trait_ref(id.def_id.to_def_id()) {
+                    let simplified_self_ty = fast_reject::simplify_type(
+                        self.tcx,
+                        trait_ref.self_ty(),
+                        TreatParams::AsPlaceholders,
+                    );
+
+                    fx_hash_map
+                        .entry(trait_ref.def_id)
+                        .or_default()
+                        .push((id.def_id.local_def_index, simplified_self_ty));
+                }
+            }
+        }
+
+        let mut all_impls: Vec<_> = fx_hash_map.into_iter().collect();
 
         // Bring everything into deterministic order for hashing
         all_impls.sort_by_cached_key(|&(trait_def_id, _)| tcx.def_path_hash(trait_def_id));
@@ -2049,41 +2066,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     }
 }
 
-struct ImplsVisitor<'tcx> {
-    tcx: TyCtxt<'tcx>,
-    impls: FxHashMap<DefId, Vec<(DefIndex, Option<SimplifiedType>)>>,
-}
-
-impl<'tcx, 'v> ItemLikeVisitor<'v> for ImplsVisitor<'tcx> {
-    fn visit_item(&mut self, item: &hir::Item<'_>) {
-        match item.kind {
-            hir::ItemKind::Impl(..) => {
-                if let Some(trait_ref) = self.tcx.impl_trait_ref(item.def_id.to_def_id()) {
-                    let simplified_self_ty = fast_reject::simplify_type(
-                        self.tcx,
-                        trait_ref.self_ty(),
-                        TreatParams::AsPlaceholders,
-                    );
-
-                    self.impls
-                        .entry(trait_ref.def_id)
-                        .or_default()
-                        .push((item.def_id.local_def_index, simplified_self_ty));
-                }
-            }
-            _ => {}
-        }
-    }
-
-    fn visit_trait_item(&mut self, _trait_item: &'v hir::TraitItem<'v>) {}
-
-    fn visit_impl_item(&mut self, _impl_item: &'v hir::ImplItem<'v>) {
-        // handled in `visit_item` above
-    }
-
-    fn visit_foreign_item(&mut self, _foreign_item: &'v hir::ForeignItem<'v>) {}
-}
-
 /// Used to prefetch queries which will be needed later by metadata encoding.
 /// Only a subset of the queries are actually prefetched to keep this code smaller.
 fn prefetch_mir(tcx: TyCtxt<'_>) {