Auto merge of #142455 - jdonszelmann:attempt-to-mitigate-delayed-lint-perf-problems, r=oli-obk

collect delayed lints in hir_crate_items

r? `@oli-obk`

Attempt to mitigate perf problems in rust-lang/rust#138164

1 files changed, 33 insertions, 5 deletions

diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index 4f699462ac3..7c8c9425a03 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -193,13 +193,41 @@ pub fn check_crate(tcx: TyCtxt<'_>) {
         let _: R = tcx.ensure_ok().crate_inherent_impls_overlap_check(());
     });
 
-    for owner_id in tcx.hir_crate_items(()).owners() {
-        if let Some(delayed_lints) = tcx.opt_ast_lowering_delayed_lints(owner_id) {
-            for lint in &delayed_lints.lints {
-                emit_delayed_lint(lint, tcx);
+    tcx.sess.time("emit_ast_lowering_delayed_lints", || {
+        // sanity check in debug mode that all lints are really noticed
+        // and we really will emit them all in the loop right below.
+        //
+        // during ast lowering, when creating items, foreign items, trait items and impl items
+        // we store in them whether they have any lints in their owner node that should be
+        // picked up by `hir_crate_items`. However, theoretically code can run between that
+        // boolean being inserted into the item and the owner node being created.
+        // We don't want any new lints to be emitted there
+        // (though honestly, you have to really try to manage to do that but still),
+        // but this check is there to catch that.
+        #[cfg(debug_assertions)]
+        {
+            // iterate over all owners
+            for owner_id in tcx.hir_crate_items(()).owners() {
+                // if it has delayed lints
+                if let Some(delayed_lints) = tcx.opt_ast_lowering_delayed_lints(owner_id) {
+                    if !delayed_lints.lints.is_empty() {
+                        // assert that delayed_lint_items also picked up this item to have lints
+                        assert!(
+                            tcx.hir_crate_items(()).delayed_lint_items().any(|i| i == owner_id)
+                        );
+                    }
+                }
             }
         }
-    }
+
+        for owner_id in tcx.hir_crate_items(()).delayed_lint_items() {
+            if let Some(delayed_lints) = tcx.opt_ast_lowering_delayed_lints(owner_id) {
+                for lint in &delayed_lints.lints {
+                    emit_delayed_lint(lint, tcx);
+                }
+            }
+        }
+    });
 
     tcx.par_hir_body_owners(|item_def_id| {
         let def_kind = tcx.def_kind(item_def_id);