[clang][frontend] Allow custom blacklist for checking objc descendant

Reviewed By: dulmarod

Differential Revision: D3940347

fbshipit-source-id: 3142727

infer/src/backend/utils.ml

@@ -97,6 +97,16 @@ module StringSet = Set.Make(String)
 let pp_stringset fmt ss =
   StringSet.iter (fun s -> F.fprintf fmt "%s " s) ss
 
+(** string list -> StringSet.t
+    from http://stackoverflow.com/a/2382330 *)
+let string_set_of_list list =
+  IList.fold_left (fun acc x -> StringSet.add x acc) StringSet.empty list
+
+(** intersection of two string lists, as a StringSet.t
+    from http://stackoverflow.com/a/2382330 *)
+let string_list_intersection a b =
+  StringSet.inter (string_set_of_list a) (string_set_of_list b)
+
 (** Maps from integers *)
 module IntMap = Map.Make (struct
     type t = int

infer/src/backend/utils.mli

@@ -92,6 +92,12 @@ module StringSet : Set.S with type elt = string
 (** Pretty print a set of strings *)
 val pp_stringset : Format.formatter -> StringSet.t -> unit
 
+(** list of strings -> set of strings *)
+val string_set_of_list : string list -> StringSet.t
+
+(** List intersection *)
+val string_list_intersection : string list -> string list -> StringSet.t
+
 (** Maps from integers *)
 module IntMap : Map.S with type key = int
 

infer/src/clang/cFrontend_utils.ml

@@ -442,22 +442,29 @@ struct
     let file_opt = (fst decl_info.Clang_ast_t.di_source_range).Clang_ast_t.sl_file in
     opt_equal string_equal file_opt Config.source_file && Option.is_some file_opt
 
-  let rec is_objc_if_descendant if_decl ancestors =
-    match if_decl with
-    | Some Clang_ast_t.ObjCInterfaceDecl (_, ndi, _, _, _)->
-        let open CFrontend_config in
-        let blacklist = [nsobject_cl; nsproxy_cl] in
-        let in_list some_list = IList.mem string_equal ndi.Clang_ast_t.ni_name some_list in
-        if in_list ancestors then
-          true
-        else if in_list blacklist then
-          false
-        else
-          (match get_super_if if_decl with
-           | Some super_decl ->
-               is_objc_if_descendant (Some super_decl) ancestors
-           | None -> false)
-    | _ -> false
+  let default_blacklist =
+    let open CFrontend_config in
+    [nsobject_cl; nsproxy_cl]
+
+  let rec is_objc_if_descendant ?(blacklist = default_blacklist) if_decl ancestors =
+    (* List of ancestors to check for and list of classes to short-circuit to
+       false can't intersect *)
+    if not (StringSet.is_empty (string_list_intersection blacklist ancestors)) then
+      failwith "Blacklist and ancestors must be mutually exclusive."
+    else
+      match if_decl with
+      | Some Clang_ast_t.ObjCInterfaceDecl (_, ndi, _, _, _) ->
+          let in_list some_list = IList.mem string_equal ndi.Clang_ast_t.ni_name some_list in
+          if in_list ancestors then
+            true
+          else if in_list blacklist then
+            false
+          else
+            (match get_super_if if_decl with
+             | Some super_decl ->
+                 is_objc_if_descendant (Some super_decl) ancestors
+             | None -> false)
+      | _ -> false
 
 (*
   let rec getter_attribute_opt attributes =

infer/src/clang/cFrontend_utils.mli

@@ -165,8 +165,11 @@ sig
       eventual descendant of one of the classes passed in.
       Ancestors param is a list of strings that represent the class names.
       Will short-circuit on NSObject and NSProxy since those are known to be
-      common base classes. *)
-  val is_objc_if_descendant : Clang_ast_t.decl option -> (string) list -> bool
+      common base classes.
+      The list of classes to short-circuit on can be overridden via specifying
+      the named `blacklist` argument. *)
+  val is_objc_if_descendant :
+    ?blacklist:string list -> Clang_ast_t.decl option -> string list -> bool
 
 end