diff --git a/contrib/gcc/unwind-dw2.c b/contrib/gcc/unwind-dw2.c
index 62c9d0913158..1b41242184e6 100644
--- a/contrib/gcc/unwind-dw2.c
+++ b/contrib/gcc/unwind-dw2.c
@@ -1393,7 +1393,16 @@ uw_advance_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
 static inline void
 init_dwarf_reg_size_table (void)
 {
+/*
+ * ARM64TODO: http://llvm.org/pr22997
+ * llvm 3.6 doesn't support __builtin_init_dwarf_reg_size_table on AArch64.
+ */
+#ifdef __aarch64__
+  printf("Unimplemented: init_dwarf_reg_size_table\n");
+  abort();
+#else
   __builtin_init_dwarf_reg_size_table (dwarf_reg_size_table);
+#endif
 }
 
 static void