diff --git a/src/Driver.ml b/src/Driver.ml
index ee147f3c2..64a456abe 100644
--- a/src/Driver.ml
+++ b/src/Driver.ml
@@ -143,7 +143,7 @@ class options args =
       Filename.chop_suffix (Filename.basename self#get_infile) ".lama"
 
     method topname =
-      match !mode with `Compile -> "init" ^ self#basename | _ -> "main"
+      match !mode with `Compile -> "init" ^ self#basename | _ -> "_main"
 
     method dump_file ext contents =
       let name = self#basename in
diff --git a/src/SM.ml b/src/SM.ml
index b72ad4e5b..dedb2a05c 100644
--- a/src/SM.ml
+++ b/src/SM.ml
@@ -14,8 +14,10 @@ type scope = {
 }
 [@@deriving gt ~options:{ show }]
 
-let label s = "_L" ^ s
-let builtin_label s = "_B" ^ s
+let normal_prefix = "_L"
+let builtin_prefix = "_B"
+let label s = normal_prefix ^ s
+let builtin_label s = builtin_prefix ^ s
 let scope_label i s = label s ^ "_" ^ string_of_int i
 let show_scope = show scope