Auto merge of #88435 - cjgillot:no-walk-crate, r=Aaron1011

Avoid invoking the hir_crate query to traverse the HIR

Walking the HIR tree is done using the `hir_crate` query. However, this is unnecessary, since `hir_owner(CRATE_DEF_ID)` provides the same information. Since depending on `hir_crate` forces dependents to always be executed, this leads to unnecessary work.

By splitting HIR and attributes visits, we can avoid an edge to `hir_crate` when trying to visit the HIR tree.

compiler/rustc_passes/src/dead.rs

@@ -775,5 +775,5 @@ pub fn check_crate(tcx: TyCtxt<'_>) {
     let krate = tcx.hir().krate();
     let live_symbols = find_live(tcx, access_levels, krate);
     let mut visitor = DeadVisitor { tcx, live_symbols };
-    intravisit::walk_crate(&mut visitor, krate);
+    tcx.hir().walk_toplevel_module(&mut visitor);
 }

compiler/rustc_passes/src/hir_id_validator.rs

@@ -11,6 +11,10 @@ use rustc_middle::ty::TyCtxt;
 pub fn check_crate(tcx: TyCtxt<'_>) {
     tcx.dep_graph.assert_ignored();
 
+    if tcx.sess.opts.debugging_opts.hir_stats {
+        crate::hir_stats::print_hir_stats(tcx);
+    }
+
     let errors = Lock::new(Vec::new());
     let hir_map = tcx.hir();
 

compiler/rustc_passes/src/hir_stats.rs

@@ -9,6 +9,7 @@ use rustc_hir as hir;
 use rustc_hir::intravisit as hir_visit;
 use rustc_hir::HirId;
 use rustc_middle::hir::map::Map;
+use rustc_middle::ty::TyCtxt;
 use rustc_middle::util::common::to_readable_str;
 use rustc_span::Span;
 
@@ -25,18 +26,19 @@ struct NodeData {
 }
 
 struct StatCollector<'k> {
-    krate: Option<&'k hir::Crate<'k>>,
+    krate: Option<Map<'k>>,
     data: FxHashMap<&'static str, NodeData>,
     seen: FxHashSet<Id>,
 }
 
-pub fn print_hir_stats(krate: &hir::Crate<'_>) {
+pub fn print_hir_stats(tcx: TyCtxt<'_>) {
     let mut collector = StatCollector {
-        krate: Some(krate),
+        krate: Some(tcx.hir()),
         data: FxHashMap::default(),
         seen: FxHashSet::default(),
     };
-    hir_visit::walk_crate(&mut collector, krate);
+    tcx.hir().walk_toplevel_module(&mut collector);
+    tcx.hir().walk_attributes(&mut collector);
     collector.print("HIR STATS");
 }
 

compiler/rustc_passes/src/lib_features.rs

@@ -6,7 +6,7 @@
 
 use rustc_ast::{Attribute, MetaItem, MetaItemKind};
 use rustc_errors::struct_span_err;
-use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
+use rustc_hir::intravisit::{NestedVisitorMap, Visitor};
 use rustc_middle::hir::map::Map;
 use rustc_middle::middle::lib_features::LibFeatures;
 use rustc_middle::ty::query::Providers;
@@ -126,9 +126,7 @@ impl Visitor<'tcx> for LibFeatureCollector<'tcx> {
 
 fn get_lib_features(tcx: TyCtxt<'_>, (): ()) -> LibFeatures {
     let mut collector = LibFeatureCollector::new(tcx);
-    let krate = tcx.hir().krate();
-
-    intravisit::walk_crate(&mut collector, krate);
+    tcx.hir().walk_attributes(&mut collector);
     collector.lib_features
 }
 

compiler/rustc_passes/src/stability.rs

@@ -8,6 +8,7 @@ use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_hir::hir_id::CRATE_HIR_ID;
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::{FieldDef, Generics, HirId, Item, TraitRef, Ty, TyKind, Variant};
 use rustc_middle::hir::map::Map;
@@ -678,7 +679,6 @@ fn stability_index(tcx: TyCtxt<'tcx>, (): ()) -> Index<'tcx> {
         .collect();
 
     {
-        let krate = tcx.hir().krate();
         let mut annotator = Annotator {
             tcx,
             index: &mut index,
@@ -711,13 +711,13 @@ fn stability_index(tcx: TyCtxt<'tcx>, (): ()) -> Index<'tcx> {
 
         annotator.annotate(
             CRATE_DEF_ID,
-            krate.module().inner,
+            tcx.hir().span(CRATE_HIR_ID),
             None,
             AnnotationKind::Required,
             InheritDeprecation::Yes,
             InheritConstStability::No,
             InheritStability::No,
-            |v| intravisit::walk_crate(v, krate),
+            |v| tcx.hir().walk_toplevel_module(v),
         );
     }
     index
@@ -908,8 +908,8 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
     if tcx.stability().staged_api[&LOCAL_CRATE] {
         let krate = tcx.hir().krate();
         let mut missing = MissingStabilityAnnotations { tcx, access_levels };
-        missing.check_missing_stability(CRATE_DEF_ID, krate.module().inner);
-        intravisit::walk_crate(&mut missing, krate);
+        missing.check_missing_stability(CRATE_DEF_ID, tcx.hir().span(CRATE_HIR_ID));
+        tcx.hir().walk_toplevel_module(&mut missing);
         krate.visit_all_item_likes(&mut missing.as_deep_visitor());
     }