diff --git a/infer/src/bufferoverrun/arrayBlk.ml b/infer/src/bufferoverrun/arrayBlk.ml
index b8106ff00..215e48990 100644
--- a/infer/src/bufferoverrun/arrayBlk.ml
+++ b/infer/src/bufferoverrun/arrayBlk.ml
@@ -247,9 +247,9 @@ module ArrInfo = struct
         Top
 
 
-  let offsetof = function C {offset} -> offset | Java _ -> Itv.zero | Top -> Itv.top
+  let get_offset = function C {offset} -> offset | Java _ -> Itv.zero | Top -> Itv.top
 
-  let sizeof = function C {size} -> size | Java {length} -> length | Top -> Itv.top
+  let get_size = function C {size} -> size | Java {length} -> length | Top -> Itv.top
 
   let byte_size = function
     | C {size; stride} ->
@@ -304,9 +304,9 @@ let join_itv : cost_mode:bool -> f:(ArrInfo.t -> Itv.t) -> t -> Itv.t =
   fold (fun _ arr -> join (f arr)) a init
 
 
-let offsetof ?(cost_mode = false) = join_itv ~cost_mode ~f:ArrInfo.offsetof
+let get_offset ?(cost_mode = false) = join_itv ~cost_mode ~f:ArrInfo.get_offset
 
-let sizeof ?(cost_mode = false) = join_itv ~cost_mode ~f:ArrInfo.sizeof
+let get_size ?(cost_mode = false) = join_itv ~cost_mode ~f:ArrInfo.get_size
 
 let plus_offset : t -> Itv.t -> t = fun arr i -> map (fun a -> ArrInfo.plus_offset a i) arr
 
diff --git a/infer/src/bufferoverrun/arrayBlk.mli b/infer/src/bufferoverrun/arrayBlk.mli
new file mode 100644
index 000000000..7e4277a34
--- /dev/null
+++ b/infer/src/bufferoverrun/arrayBlk.mli
@@ -0,0 +1,95 @@
+(*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *)
+
+open! IStd
+
+module ArrInfo : sig
+  type t
+
+  val byte_size : t -> Itv.t
+  (** Return size of array block as bytes *)
+
+  val get_offset : t -> Itv.t
+  (** Return current offset of array block *)
+
+  val get_size : t -> Itv.t
+  (** Return size of array block, i.e., number of cells *)
+end
+
+include AbstractDomain.MapS with type key = AbsLoc.Allocsite.t and type value = ArrInfo.t
+
+val compare : t -> t -> int
+
+val bot : t
+
+val make_c : AbsLoc.Allocsite.t -> offset:Itv.t -> size:Itv.t -> stride:Itv.t -> t
+(** Make an array block for C *)
+
+val make_java : AbsLoc.Allocsite.t -> length:Itv.t -> t
+(** Make an array block for Java *)
+
+val unknown : t
+
+val get_pow_loc : t -> AbsLoc.PowLoc.t
+(** Return all allocsites as [PowLoc.t] *)
+
+val is_bot : t -> bool
+
+val is_symbolic : t -> bool
+(** Check if there is a symbolic integer value in its offset or size *)
+
+val lift_cmp_itv : (Itv.t -> Itv.t -> Boolean.t) -> Boolean.EqualOrder.t -> t -> t -> Boolean.t
+(** Lift a comparison of [Itv.t] and [Loc.t] to that of [t].  The comparison for [Itv.t] is used for
+   integer values such as offset and size, and the comparison for [Loc.t] is used for allocsites. *)
+
+val transform_length : f:(Itv.t -> Itv.t) -> t -> t
+(** Apply [f] to all sizes *)
+
+val prune_comp : Binop.t -> t -> t -> t
+(** [prune_comp comp x y] returns a pruned value of [x] by [comp] and [y]. [comp] should be
+   [Binop.Le], [Ge], [Lt], or [Gt]. *)
+
+val prune_eq : t -> t -> t
+(** [prune_eq x y] returns a pruned value of [x] by [== y]. *)
+
+val prune_ne : t -> t -> t
+(** [prune_ne x y] returns a pruned value of [x] by [!= y]. *)
+
+val minus_offset : t -> Itv.t -> t
+
+val plus_offset : t -> Itv.t -> t
+
+val diff : t -> t -> Itv.t
+(** Return difference of offsets between given array blocks *)
+
+val normalize : t -> t
+(** Normalize all interval values such as offset and size in it.  Thus, if an interval value is
+   invalid, the interval value is replaced with bottom. *)
+
+val subst : t -> Bounds.Bound.eval_sym -> AbsLoc.PowLoc.eval_locpath -> AbsLoc.PowLoc.t * t
+(** Substitute symbolic abstract locations and symbolic interval value in the array block.
+   [eval_sym] is to get substituted interval values and [eval_locpath] is to get substituted
+   abstract locaion values.  It also returns a set of abstract locations containing non-allocsite
+   locations from the substitution results.  Since the key of [ArrayBlk.t] is [AbsLoc.Allocsite.t],
+   they cannot be written in this domain. *)
+
+val set_length : Itv.t -> t -> t
+
+val set_offset : Itv.t -> t -> t
+
+val set_stride : Z.t -> t -> t
+
+val get_symbols : t -> Symb.SymbolSet.t
+(** Return all symbols for integer values in it *)
+
+val get_offset : ?cost_mode:bool -> t -> Itv.t
+(** Return offset of the array block.  If [cost_mode] is [true], it returns a conservative
+   (bigger than correct one), but not correct offset results. *)
+
+val get_size : ?cost_mode:bool -> t -> Itv.t
+(** Return size of the array block.  If [cost_mode] is [true], it returns a conservative (bigger
+   than correct one), but not correct size results. *)
diff --git a/infer/src/bufferoverrun/bufferOverrunDomain.ml b/infer/src/bufferoverrun/bufferOverrunDomain.ml
index 8b0dc9452..8b8be2ed4 100644
--- a/infer/src/bufferoverrun/bufferOverrunDomain.ml
+++ b/infer/src/bufferoverrun/bufferOverrunDomain.ml
@@ -505,7 +505,7 @@ module Val = struct
     {x with traces}
 
 
-  let array_sizeof {arrayblk} = ArrayBlk.sizeof arrayblk
+  let array_sizeof {arrayblk} = ArrayBlk.get_size arrayblk
 
   let set_array_length : Location.t -> length:t -> t -> t =
    fun location ~length v ->
diff --git a/infer/src/bufferoverrun/bufferOverrunModels.ml b/infer/src/bufferoverrun/bufferOverrunModels.ml
index 3c1ce879c..2d8999451 100644
--- a/infer/src/bufferoverrun/bufferOverrunModels.ml
+++ b/infer/src/bufferoverrun/bufferOverrunModels.ml
@@ -100,7 +100,7 @@ let fgets str_exp num_exp =
     let traces = Trace.Set.join (Dom.Val.get_traces str_v) (Dom.Val.get_traces num_v) in
     let update_strlen1 allocsite arrinfo acc =
       let strlen =
-        let offset = ArrayBlk.ArrInfo.offsetof arrinfo in
+        let offset = ArrayBlk.ArrInfo.get_offset arrinfo in
         let num = Dom.Val.get_itv num_v in
         Itv.plus offset (Itv.set_lb_zero (Itv.decr num))
       in
@@ -471,7 +471,7 @@ module CFArray = struct
   let length e =
     let exec {integer_type_widths} ~ret:(ret_id, _) mem =
       let v = Sem.eval_arr integer_type_widths e mem in
-      let length = Dom.Val.of_itv (ArrayBlk.sizeof (Dom.Val.get_array_blk v)) in
+      let length = Dom.Val.of_itv (ArrayBlk.get_size (Dom.Val.get_array_blk v)) in
       Dom.Mem.add_stack (Loc.of_id ret_id) length mem
     in
     {exec; check= no_check}
@@ -673,7 +673,7 @@ module StdVector = struct
       let deref_of_vec = deref_of model_env elt_typ vec_arg mem in
       let array_v = Dom.Mem.find_set deref_of_vec mem in
       let traces = Dom.Val.get_traces array_v in
-      let size = ArrayBlk.sizeof (Dom.Val.get_array_blk array_v) in
+      let size = ArrayBlk.get_size (Dom.Val.get_array_blk array_v) in
       let empty = Dom.Val.of_itv ~traces (Itv.of_bool (Itv.le_sem size Itv.zero)) in
       let mem = model_by_value empty id mem in
       match PowLoc.is_singleton_or_more deref_of_vec with
diff --git a/infer/src/bufferoverrun/bufferOverrunSemantics.ml b/infer/src/bufferoverrun/bufferOverrunSemantics.ml
index 77519e442..070ebb266 100644
--- a/infer/src/bufferoverrun/bufferOverrunSemantics.ml
+++ b/infer/src/bufferoverrun/bufferOverrunSemantics.ml
@@ -441,10 +441,10 @@ let eval_sympath ~mode params sympath mem =
       (Val.get_itv v, Val.get_traces v)
   | Symb.SymbolPath.Offset {p} ->
       let v = eval_sympath_partial ~mode params p mem in
-      (ArrayBlk.offsetof ~cost_mode:(is_cost_mode mode) (Val.get_array_blk v), Val.get_traces v)
+      (ArrayBlk.get_offset ~cost_mode:(is_cost_mode mode) (Val.get_array_blk v), Val.get_traces v)
   | Symb.SymbolPath.Length {p} ->
       let v = eval_sympath_partial ~mode params p mem in
-      (ArrayBlk.sizeof ~cost_mode:(is_cost_mode mode) (Val.get_array_blk v), Val.get_traces v)
+      (ArrayBlk.get_size ~cost_mode:(is_cost_mode mode) (Val.get_array_blk v), Val.get_traces v)
 
 
 let mk_eval_sym_trace integer_type_widths (callee_formals : (Pvar.t * Typ.t) list)
@@ -498,7 +498,7 @@ let eval_array_locs_length arr_locs mem =
   else
     let arr = Mem.find_set arr_locs mem in
     let traces = Val.get_traces arr in
-    let length = Val.get_array_blk arr |> ArrayBlk.sizeof in
+    let length = Val.get_array_blk arr |> ArrayBlk.get_size in
     match Itv.get_bound length Symb.BoundEnd.UpperBound with
     | NonBottom b when not (Bounds.Bound.is_pinf b) ->
         Val.of_itv ~traces length
@@ -645,7 +645,7 @@ module Prune = struct
         ~f:(fun astate (alias_typ, lv, i, java_tmp) ->
           let array_v = Mem.find lv mem in
           let lhs =
-            Val.get_array_blk array_v |> ArrayBlk.sizeof
+            Val.get_array_blk array_v |> ArrayBlk.get_size
             |> Itv.plus (Itv.of_int_lit i)
             |> Val.of_itv |> Val.set_itv_updated_by_addition
           in
diff --git a/infer/src/bufferoverrun/bufferOverrunUtils.ml b/infer/src/bufferoverrun/bufferOverrunUtils.ml
index 895bcc24f..0930f7366 100644
--- a/infer/src/bufferoverrun/bufferOverrunUtils.ml
+++ b/infer/src/bufferoverrun/bufferOverrunUtils.ml
@@ -231,7 +231,7 @@ module Exec = struct
     let src_itv = Dom.Val.get_itv src in
     let set_c_strlen1 allocsite arrinfo acc =
       let loc = Loc.of_allocsite allocsite in
-      let idx = Dom.Val.of_itv ~traces (ArrayBlk.ArrInfo.offsetof arrinfo) in
+      let idx = Dom.Val.of_itv ~traces (ArrayBlk.ArrInfo.get_offset arrinfo) in
       if Itv.leq ~lhs:Itv.zero ~rhs:src_itv then Dom.Mem.set_first_idx_of_null loc idx acc
       else Dom.Mem.unset_first_idx_of_null loc idx acc
     in
@@ -256,7 +256,7 @@ module Check = struct
 
 
   let offsetof arr_info =
-    match ArrayBlk.ArrInfo.offsetof arr_info with
+    match ArrayBlk.ArrInfo.get_offset arr_info with
     | Bottom ->
         (* Java's collection has no offset. *)
         Itv.ItvPure.zero
@@ -280,7 +280,7 @@ module Check = struct
           op idx_sym_exp offset_sym_exp )
     in
     let array_access1 allocsite arr_info acc =
-      let size = ArrayBlk.ArrInfo.sizeof arr_info in
+      let size = ArrayBlk.ArrInfo.get_size arr_info in
       let offset = offsetof arr_info in
       log_array_access allocsite size offset idx ;
       check_access ~size ~idx ~offset ~size_sym_exp ~idx_sym_exp ~relation ~arr_traces ~idx_traces