From 852dea89b2289fe101f2bbd807c0abdd09902e08 Mon Sep 17 00:00:00 2001
From: Alik Aslanyan <inline0@protonmail.com>
Date: Tue, 21 Dec 2021 22:31:23 +0400
Subject: [PATCH] Remove ArenaCacheSelector for visible_parent_map query.
 Optimize visible_parent_map to use LRC to prevent unnecessary cloning

---
 compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs | 2 +-
 compiler/rustc_middle/src/query/mod.rs                   | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 4e5d21049a0d9..3f3b83cf79571 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -360,7 +360,7 @@ pub fn provide(providers: &mut Providers) {
                 visible_parent_map.entry(child).or_insert(parent);
             }
 
-            visible_parent_map
+            Lrc::new(visible_parent_map)
         },
 
         dependency_formats: |tcx, ()| Lrc::new(crate::dependency_format::calculate(tcx)),
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index ad3f61d07843a..81602dc9d61c4 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -1552,8 +1552,7 @@ rustc_queries! {
         desc { "calculating the missing lang items in a crate" }
         separate_provide_extern
     }
-    query visible_parent_map(_: ()) -> DefIdMap<DefId> {
-        storage(ArenaCacheSelector<'tcx>)
+    query visible_parent_map(_: ()) -> Lrc<DefIdMap<DefId>> {
         desc { "calculating the visible parent map" }
     }
     query trimmed_def_paths(_: ()) -> FxHashMap<DefId, Symbol> {