diff --git a/gdb/dwarf2/cooked-index-entry.c b/gdb/dwarf2/cooked-index-entry.c
index a5e3fcb6caa..0482b640f85 100644
--- a/gdb/dwarf2/cooked-index-entry.c
+++ b/gdb/dwarf2/cooked-index-entry.c
@@ -188,8 +188,15 @@ cooked_index_entry::full_name (struct obstack *storage,
       break;
 
     case language_ada:
+      /* If GNAT emits hierarchical names (patches not in at the time
+	 of writing), then we need to compute the linkage name here.
+	 However for traditional GNAT, the linkage name will be in
+	 'name'.  Detect this by looking for "__"; see also
+	 cooked_index_shard::finalize.  */
       if ((name_flags & FOR_ADA_LINKAGE_NAME) != 0)
 	{
+	  if (strstr (name, "__") != nullptr)
+	    return name;
 	  sep = "__";
 	  break;
 	}