Change Hashtbl.clear to Hashtbl.reset

Summary:
Replace Hashtbl.clear with Hashtbl.reset

This saves memory because the reset method shrinks the hash-table, whereas the clear method just empties it

Reviewed By: jvillard

Differential Revision: D16004966

fbshipit-source-id: f32b00b0f

infer/src/backend/CallGraph.ml

@@ -46,7 +46,7 @@ module NodeMap = Caml.Hashtbl.Make (Int)
     [trim_id_map] makes the image equal to the domain of [node_map]. *)
 type t = {id_map: int IdMap.t; node_map: Node.t NodeMap.t}
 
-let clear {id_map; node_map} = IdMap.clear id_map ; NodeMap.clear node_map
+let reset {id_map; node_map} = IdMap.reset id_map ; NodeMap.reset node_map
 
 let create initial_capacity =
   {id_map= IdMap.create initial_capacity; node_map= NodeMap.create initial_capacity}

infer/src/backend/CallGraph.mli

@@ -23,7 +23,7 @@ module Node : NodeSig
 
 type t
 
-val clear : t -> unit
+val reset : t -> unit
 
 val create : int -> t
 (** [create n] makes an empty graph with initial capacity [n] which grows as required *)

infer/src/backend/TaskScheduler.ml

@@ -55,7 +55,7 @@ let bottom_up sources : target task_generator =
         (CallGraph.n_procs g) ;
       if Config.debug_level_analysis > 0 then CallGraph.to_dotty g "cycles.dot" ;
       (* save some memory *)
-      CallGraph.clear g ) ;
+      CallGraph.reset g ) ;
     empty
   in
   let rec next_aux () =