diff --git a/src/librustc/arena.rs b/src/librustc/arena.rs
index de0e780b261..e6808e0f3bf 100644
--- a/src/librustc/arena.rs
+++ b/src/librustc/arena.rs
@@ -60,6 +60,13 @@ macro_rules! arena_types {
                 >,
             [few] crate_inherent_impls: rustc::ty::CrateInherentImpls,
             [decode] borrowck: rustc::middle::borrowck::BorrowCheckResult,
+            [few] upstream_monomorphizations:
+                rustc::util::nodemap::DefIdMap<
+                    rustc_data_structures::fx::FxHashMap<
+                        rustc::ty::subst::SubstsRef<'tcx>,
+                        rustc::hir::def_id::CrateNum
+                    >
+                >,
         ], $tcx);
     )
 }
diff --git a/src/librustc/query/mod.rs b/src/librustc/query/mod.rs
index 3594635f41a..2e2cb2db838 100644
--- a/src/librustc/query/mod.rs
+++ b/src/librustc/query/mod.rs
@@ -681,11 +681,11 @@ rustc_queries! {
     Codegen {
         query upstream_monomorphizations(
             k: CrateNum
-        ) -> Lrc<DefIdMap<Lrc<FxHashMap<SubstsRef<'tcx>, CrateNum>>>> {
+        ) -> &'tcx DefIdMap<FxHashMap<SubstsRef<'tcx>, CrateNum>> {
             desc { "collecting available upstream monomorphizations `{:?}`", k }
         }
         query upstream_monomorphizations_for(_: DefId)
-            -> Option<Lrc<FxHashMap<SubstsRef<'tcx>, CrateNum>>> {}
+            -> Option<&'tcx FxHashMap<SubstsRef<'tcx>, CrateNum>> {}
     }
 
     Other {
diff --git a/src/librustc_codegen_ssa/back/symbol_export.rs b/src/librustc_codegen_ssa/back/symbol_export.rs
index a55f783df43..616049ea112 100644
--- a/src/librustc_codegen_ssa/back/symbol_export.rs
+++ b/src/librustc_codegen_ssa/back/symbol_export.rs
@@ -282,7 +282,7 @@ fn exported_symbols_provider_local<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 fn upstream_monomorphizations_provider<'a, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     cnum: CrateNum)
-    -> Lrc<DefIdMap<Lrc<FxHashMap<SubstsRef<'tcx>, CrateNum>>>>
+    -> &'tcx DefIdMap<FxHashMap<SubstsRef<'tcx>, CrateNum>>
 {
     debug_assert!(cnum == LOCAL_CRATE);
 
@@ -326,20 +326,16 @@ fn upstream_monomorphizations_provider<'a, 'tcx>(
         }
     }
 
-    Lrc::new(instances.into_iter()
-                      .map(|(key, value)| (key, Lrc::new(value)))
-                      .collect())
+    tcx.arena.alloc(instances)
 }
 
 fn upstream_monomorphizations_for_provider<'a, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     def_id: DefId)
-    -> Option<Lrc<FxHashMap<SubstsRef<'tcx>, CrateNum>>>
+    -> Option<&'tcx FxHashMap<SubstsRef<'tcx>, CrateNum>>
 {
     debug_assert!(!def_id.is_local());
-    tcx.upstream_monomorphizations(LOCAL_CRATE)
-       .get(&def_id)
-       .cloned()
+    tcx.upstream_monomorphizations(LOCAL_CRATE).get(&def_id)
 }
 
 fn is_unreachable_local_definition_provider(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {