Parallelize type collecting and item-types checking

Author: Zoxc

compiler/rustc_hir_analysis/src/check/check.rs

@@ -1447,9 +1447,7 @@ pub(super) fn check_type_params_are_used<'tcx>(
 
 pub(super) fn check_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
     let module = tcx.hir_module_items(module_def_id);
-    for id in module.items() {
-        check_item_type(tcx, id);
-    }
+    module.par_items(|id| check_item_type(tcx, id));
     if module_def_id == LocalModDefId::CRATE_DEF_ID {
         super::entry::check_for_entry_fn(tcx);
     }

compiler/rustc_hir_analysis/src/collect.rs

@@ -50,7 +50,7 @@ mod type_of;
 // Main entry point
 
 fn collect_mod_item_types(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
-    tcx.hir().visit_item_likes_in_module(module_def_id, &mut CollectItemTypesVisitor { tcx });
+    tcx.hir().par_visit_item_likes_in_module(module_def_id, || CollectItemTypesVisitor { tcx });
 }
 
 pub fn provide(providers: &mut Providers) {

compiler/rustc_hir_analysis/src/lib.rs

@@ -168,7 +168,11 @@ pub fn check_crate(tcx: TyCtxt<'_>) -> Result<(), ErrorGuaranteed> {
     // FIXME(matthewjasper) We shouldn't need to use `track_errors`.
     tcx.sess.track_errors(|| {
         tcx.sess.time("type_collecting", || {
-            tcx.hir().for_each_module(|module| tcx.ensure().collect_mod_item_types(module))
+            // Run dependencies of type collecting before entering the loop
+            tcx.ensure_with_value().inferred_outlives_crate(());
+
+            let _prof_timer = tcx.sess.timer("type_collecting_loop");
+            tcx.hir().par_for_each_module(|module| tcx.ensure().collect_mod_item_types(module));
         });
     })?;
 

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

@@ -619,6 +619,34 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    /// A parallel version of `visit_item_likes_in_module`.
+    pub fn par_visit_item_likes_in_module<V>(
+        &self,
+        module: LocalModDefId,
+        make_visitor: impl Fn() -> V + DynSync,
+    ) where
+        V: Visitor<'hir>,
+    {
+        let module = self.tcx.hir_module_items(module);
+
+        parallel!(
+            {
+                module.par_items(|id| make_visitor().visit_item(self.item(id)));
+            },
+            {
+                module.par_trait_items(|id| make_visitor().visit_trait_item(self.trait_item(id)));
+            },
+            {
+                module.par_impl_items(|id| make_visitor().visit_impl_item(self.impl_item(id)));
+            },
+            {
+                module.par_foreign_items(|id| {
+                    make_visitor().visit_foreign_item(self.foreign_item(id))
+                });
+            }
+        );
+    }
+
     pub fn for_each_module(self, mut f: impl FnMut(LocalModDefId)) {
         let crate_items = self.tcx.hir_crate_items(());
         for module in crate_items.submodules.iter() {