[clang] Reimplement removing nodes from procdesc in a more efficient way

infer/src/backend/cfg.ml

@@ -60,7 +60,6 @@ module Node = struct
   let exn_sink_kind = Stmt_node "exceptions sink"
   let throw_kind = Stmt_node "throw"
 
-
   type cfg = (** data type for the control flow graph *)
     { node_id : int ref;
       node_list : t list ref;
@@ -359,15 +358,26 @@ module Node = struct
   (** Counter for identifiers of procdescs *)
   let proc_desc_id_counter = ref 0
 
-  let remove_node cfg node =
+  let remove_node' filter_out_fun cfg node =
     let remove_node_in_cfg nodes =
-      list_filter (fun node' -> not (equal node node')) nodes in
+      list_filter filter_out_fun nodes in
     cfg.node_list := remove_node_in_cfg !(cfg.node_list)
 
+  let remove_node cfg node =
+    remove_node' (fun node' -> not (equal node node'))
+      cfg node
+
+  let remove_node_set cfg nodes =
+    remove_node' (fun node' -> not (NodeSet.mem node' nodes))
+      cfg nodes
+
   let proc_desc_remove cfg name remove_nodes =
     (if remove_nodes then
         let pdesc = pdesc_tbl_find cfg name in
-        list_iter (remove_node cfg) pdesc.pd_nodes);
+        let proc_nodes =
+          list_fold_right (fun node set -> NodeSet.add node set)
+            pdesc.pd_nodes NodeSet.empty in
+        remove_node_set cfg proc_nodes);
     pdesc_tbl_remove cfg name
 
   let proc_desc_get_start_node proc_desc =
@@ -802,6 +812,7 @@ let remove_abducted_retvars p =
       | Sil.Eexp (e, _) -> Sil.ExpSet.add e exps
       | Sil.Estruct (flds, _) ->
           list_fold_left (fun exps (_, strexp) -> collect_exps exps strexp) exps flds
+
       | Sil.Earray (_, elems, _) ->
           list_fold_left (fun exps (index, strexp) -> collect_exps exps strexp) exps elems in
     let rec compute_reachable_hpreds_rec sigma (reach, exps) =