2 files changed, 5 insertions, 1 deletions
diff --git a/compiler/rustc_const_eval/src/check_consts/mod.rs b/compiler/rustc_const_eval/src/check_consts/mod.rs
index 607cb2e497d..06ee7075170 100644
--- a/compiler/rustc_const_eval/src/check_consts/mod.rs
+++ b/compiler/rustc_const_eval/src/check_consts/mod.rs
@@ -81,7 +81,7 @@ pub fn rustc_allow_const_fn_unstable(
     def_id: LocalDefId,
     feature_gate: Symbol,
 ) -> bool {
-    let attrs = tcx.hir().attrs(tcx.local_def_id_to_hir_id(def_id));
+    let attrs = tcx.hir_attrs(tcx.local_def_id_to_hir_id(def_id));
 
     find_attr!(attrs, AttributeKind::AllowConstFnUnstable(syms) if syms.contains(&feature_gate))
 }
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index ce0b5a350e0..e5af0673629 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -982,6 +982,10 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                     todo.push(id);
                 }
             }
+            // Also expose the provenance of the interpreter-level allocation, so it can
+            // be read by FFI. The `black_box` is defensive programming as LLVM likes
+            // to (incorrectly) optimize away ptr2int casts whose result is unused.
+            std::hint::black_box(alloc.get_bytes_unchecked_raw().expose_provenance());
 
             // Prepare for possible write from native code if mutable.
             if info.mutbl.is_mut() {