[multicore][topl] make lazy automaton thread safe

Summary: Lazy evaluation is not thread safe, so a mutex is used.

Reviewed By: rgrig, jvillard

Differential Revision:
D67091750

Privacy Context Container: L1208441

fbshipit-source-id: 4a593d4b793c4f07eee959a487b9bee423df6eb6

infer/src/topl/Topl.ml

@@ -7,13 +7,15 @@
 
 open! IStd
 
+let mutex = Error_checking_mutex.create ()
+
 let automaton =
   lazy
     (ToplAutomaton.make
        (Config.topl_properties @ DataFlowQuery.convert_to_topl Config.data_flow_queries_on_topl) )
 
 
-let automaton () = Lazy.force automaton
+let automaton () = Error_checking_mutex.critical_section mutex ~f:(fun () -> Lazy.force automaton)
 
 let is_active () =
   Config.is_checker_enabled Topl