Auto merge of #95655 - kckeiks:create-hir-crate-items-query, r=cjgillot

Refactor HIR item-like traversal (part 1)

Issue  #95004

- Create hir_crate_items query which traverses tcx.hir_crate(()).owners to return a hir::ModuleItems
- use tcx.hir_crate_items in tcx.hir().items() to return an iterator of hir::ItemId
- use tcx.hir_crate_items to introduce a tcx.hir().par_items(impl Fn(hir::ItemId)) to traverse all items in parallel;

Signed-off-by: Miguel Guarniz <mi9uel9@gmail.com>

cc `@cjgillot`

1 files changed, 55 insertions, 60 deletions

diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index fdb14e45d98..0e0a4fbc215 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -181,8 +181,8 @@
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync::{par_iter, MTLock, MTRef, ParallelIterator};
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, DefIdMap, LocalDefId, LOCAL_CRATE};
-use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::lang_items::LangItem;
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_middle::mir::interpret::{AllocId, ConstValue};
@@ -327,11 +327,19 @@ fn collect_roots(tcx: TyCtxt<'_>, mode: MonoItemCollectionMode) -> Vec<MonoItem<
 
         debug!("collect_roots: entry_fn = {:?}", entry_fn);
 
-        let mut visitor = RootCollector { tcx, mode, entry_fn, output: &mut roots };
+        let mut collector = RootCollector { tcx, mode, entry_fn, output: &mut roots };
 
-        tcx.hir().visit_all_item_likes(&mut visitor);
+        let crate_items = tcx.hir_crate_items(());
 
-        visitor.push_extra_entry_roots();
+        for id in crate_items.items() {
+            collector.process_item(id);
+        }
+
+        for id in crate_items.impl_items() {
+            collector.process_impl_item(id);
+        }
+
+        collector.push_extra_entry_roots();
     }
 
     // We can only codegen items that are instantiable - items all of
@@ -1159,87 +1167,74 @@ struct RootCollector<'a, 'tcx> {
     entry_fn: Option<(DefId, EntryFnType)>,
 }
 
-impl<'v> ItemLikeVisitor<'v> for RootCollector<'_, 'v> {
-    fn visit_item(&mut self, item: &'v hir::Item<'v>) {
-        match item.kind {
-            hir::ItemKind::ExternCrate(..)
-            | hir::ItemKind::Use(..)
-            | hir::ItemKind::Macro(..)
-            | hir::ItemKind::ForeignMod { .. }
-            | hir::ItemKind::TyAlias(..)
-            | hir::ItemKind::Trait(..)
-            | hir::ItemKind::TraitAlias(..)
-            | hir::ItemKind::OpaqueTy(..)
-            | hir::ItemKind::Mod(..) => {
-                // Nothing to do, just keep recursing.
-            }
-
-            hir::ItemKind::Impl { .. } => {
-                if self.mode == MonoItemCollectionMode::Eager {
-                    create_mono_items_for_default_impls(self.tcx, item, self.output);
-                }
-            }
-
-            hir::ItemKind::Enum(_, ref generics)
-            | hir::ItemKind::Struct(_, ref generics)
-            | hir::ItemKind::Union(_, ref generics) => {
-                if generics.params.is_empty() {
-                    if self.mode == MonoItemCollectionMode::Eager {
-                        debug!(
-                            "RootCollector: ADT drop-glue for {}",
-                            self.tcx.def_path_str(item.def_id.to_def_id())
-                        );
-
-                        let ty = Instance::new(item.def_id.to_def_id(), InternalSubsts::empty())
-                            .ty(self.tcx, ty::ParamEnv::reveal_all());
-                        visit_drop_use(self.tcx, ty, true, DUMMY_SP, self.output);
+impl<'v> RootCollector<'_, 'v> {
+    fn process_item(&mut self, id: hir::ItemId) {
+        match self.tcx.hir().def_kind(id.def_id) {
+            DefKind::Enum | DefKind::Struct | DefKind::Union => {
+                let item = self.tcx.hir().item(id);
+                match item.kind {
+                    hir::ItemKind::Enum(_, ref generics)
+                    | hir::ItemKind::Struct(_, ref generics)
+                    | hir::ItemKind::Union(_, ref generics) => {
+                        if generics.params.is_empty() {
+                            if self.mode == MonoItemCollectionMode::Eager {
+                                debug!(
+                                    "RootCollector: ADT drop-glue for {}",
+                                    self.tcx.def_path_str(item.def_id.to_def_id())
+                                );
+
+                                let ty =
+                                    Instance::new(item.def_id.to_def_id(), InternalSubsts::empty())
+                                        .ty(self.tcx, ty::ParamEnv::reveal_all());
+                                visit_drop_use(self.tcx, ty, true, DUMMY_SP, self.output);
+                            }
+                        }
                     }
+                    _ => bug!(),
                 }
             }
-            hir::ItemKind::GlobalAsm(..) => {
+            DefKind::GlobalAsm => {
                 debug!(
                     "RootCollector: ItemKind::GlobalAsm({})",
-                    self.tcx.def_path_str(item.def_id.to_def_id())
+                    self.tcx.def_path_str(id.def_id.to_def_id())
                 );
-                self.output.push(dummy_spanned(MonoItem::GlobalAsm(item.item_id())));
+                self.output.push(dummy_spanned(MonoItem::GlobalAsm(id)));
             }
-            hir::ItemKind::Static(..) => {
+            DefKind::Static(..) => {
                 debug!(
                     "RootCollector: ItemKind::Static({})",
-                    self.tcx.def_path_str(item.def_id.to_def_id())
+                    self.tcx.def_path_str(id.def_id.to_def_id())
                 );
-                self.output.push(dummy_spanned(MonoItem::Static(item.def_id.to_def_id())));
+                self.output.push(dummy_spanned(MonoItem::Static(id.def_id.to_def_id())));
             }
-            hir::ItemKind::Const(..) => {
+            DefKind::Const => {
                 // const items only generate mono items if they are
                 // actually used somewhere. Just declaring them is insufficient.
 
                 // but even just declaring them must collect the items they refer to
-                if let Ok(val) = self.tcx.const_eval_poly(item.def_id.to_def_id()) {
+                if let Ok(val) = self.tcx.const_eval_poly(id.def_id.to_def_id()) {
                     collect_const_value(self.tcx, val, &mut self.output);
                 }
             }
-            hir::ItemKind::Fn(..) => {
-                self.push_if_root(item.def_id);
+            DefKind::Impl => {
+                if self.mode == MonoItemCollectionMode::Eager {
+                    let item = self.tcx.hir().item(id);
+                    create_mono_items_for_default_impls(self.tcx, item, self.output);
+                }
+            }
+            DefKind::Fn => {
+                self.push_if_root(id.def_id);
             }
+            _ => {}
         }
     }
 
-    fn visit_trait_item(&mut self, _: &'v hir::TraitItem<'v>) {
-        // Even if there's a default body with no explicit generics,
-        // it's still generic over some `Self: Trait`, so not a root.
-    }
-
-    fn visit_impl_item(&mut self, ii: &'v hir::ImplItem<'v>) {
-        if let hir::ImplItemKind::Fn(hir::FnSig { .. }, _) = ii.kind {
-            self.push_if_root(ii.def_id);
+    fn process_impl_item(&mut self, id: hir::ImplItemId) {
+        if matches!(self.tcx.hir().def_kind(id.def_id), DefKind::AssocFn) {
+            self.push_if_root(id.def_id);
         }
     }
 
-    fn visit_foreign_item(&mut self, _foreign_item: &'v hir::ForeignItem<'v>) {}
-}
-
-impl<'v> RootCollector<'_, 'v> {
     fn is_root(&self, def_id: LocalDefId) -> bool {
         !item_requires_monomorphization(self.tcx, def_id)
             && match self.mode {