From 1b2adb94226d52714a761b91677b399da584ce55 Mon Sep 17 00:00:00 2001
From: Mehdi Bouaziz <mbouaziz@fb.com>
Date: Mon, 26 Mar 2018 05:50:45 -0700
Subject: [PATCH] [inferbo] Refactoring 5/8: simplify Utils.Check.array_access

Reviewed By: jvillard

Differential Revision: D7397129

fbshipit-source-id: 6f68ee4
---
 .../src/bufferoverrun/bufferOverrunChecker.ml | 17 ++++-------
 .../src/bufferoverrun/bufferOverrunDomain.ml  |  2 ++
 infer/src/bufferoverrun/bufferOverrunUtils.ml | 28 +++++++++----------
 3 files changed, 21 insertions(+), 26 deletions(-)

diff --git a/infer/src/bufferoverrun/bufferOverrunChecker.ml b/infer/src/bufferoverrun/bufferOverrunChecker.ml
index 29a7cce48..9c698cc67 100644
--- a/infer/src/bufferoverrun/bufferOverrunChecker.ml
+++ b/infer/src/bufferoverrun/bufferOverrunChecker.ml
@@ -382,13 +382,9 @@ module Report = struct
       : Typ.Procname.t -> is_plus:bool -> e1:Exp.t -> e2:Exp.t -> Location.t -> Dom.Mem.astate
         -> PO.ConditionSet.t -> PO.ConditionSet.t =
    fun pname ~is_plus ~e1 ~e2 location mem cond_set ->
-    let v_arr = Sem.eval e1 mem in
-    let arr = Dom.Val.get_array_blk v_arr in
-    let arr_traces = Dom.Val.get_traces v_arr in
-    let v_idx = Sem.eval e2 mem in
-    let idx = Dom.Val.get_itv v_idx in
-    let idx_traces = Dom.Val.get_traces v_idx in
-    BoUtils.Check.array_access ~arr ~arr_traces ~idx ~idx_traces ~is_plus pname location cond_set
+    let arr = Sem.eval e1 mem in
+    let idx = Sem.eval e2 mem in
+    BoUtils.Check.array_access ~arr ~idx ~is_plus pname location cond_set
 
 
   let check_binop
@@ -410,11 +406,8 @@ module Report = struct
    fun pname exp location mem cond_set ->
     match exp with
     | Exp.Var _ ->
-        let v = Sem.eval exp mem in
-        let arr = Dom.Val.get_array_blk v in
-        let arr_traces = Dom.Val.get_traces v in
-        BoUtils.Check.array_access ~arr ~arr_traces ~idx:Itv.zero ~idx_traces:TraceSet.empty
-          ~is_plus:true pname location cond_set
+        let arr = Sem.eval exp mem in
+        BoUtils.Check.array_access ~arr ~idx:Dom.Val.Itv.zero ~is_plus:true pname location cond_set
     | Exp.Lindex (array_exp, index_exp) ->
         cond_set |> check_expr pname array_exp location mem
         |> check_expr pname index_exp location mem
diff --git a/infer/src/bufferoverrun/bufferOverrunDomain.ml b/infer/src/bufferoverrun/bufferOverrunDomain.ml
index 5b9f40c5d..0dbc511c9 100644
--- a/infer/src/bufferoverrun/bufferOverrunDomain.ml
+++ b/infer/src/bufferoverrun/bufferOverrunDomain.ml
@@ -259,6 +259,8 @@ module Val = struct
     let m1_255 = of_itv Itv.m1_255
 
     let top = of_itv Itv.top
+
+    let zero = of_itv Itv.zero
   end
 end
 
diff --git a/infer/src/bufferoverrun/bufferOverrunUtils.ml b/infer/src/bufferoverrun/bufferOverrunUtils.ml
index 0ad58d28b..a399da580 100644
--- a/infer/src/bufferoverrun/bufferOverrunUtils.ml
+++ b/infer/src/bufferoverrun/bufferOverrunUtils.ml
@@ -181,15 +181,19 @@ module Make (CFG : ProcCfg.S) = struct
   end
 
   module Check = struct
-    let array_access ~arr ~arr_traces ~idx ~idx_traces ~is_plus pname location cond_set =
-      let size = ArrayBlk.sizeof arr in
-      let offset = ArrayBlk.offsetof arr in
-      let idx = (if is_plus then Itv.plus else Itv.minus) offset idx in
+    let array_access ~arr ~idx ~is_plus pname location cond_set =
+      let arr_blk = Dom.Val.get_array_blk arr in
+      let arr_traces = Dom.Val.get_traces arr in
+      let size = ArrayBlk.sizeof arr_blk in
+      let offset = ArrayBlk.offsetof arr_blk in
+      let idx_itv = Dom.Val.get_itv idx in
+      let idx_traces = Dom.Val.get_traces idx in
+      let idx_in_blk = (if is_plus then Itv.plus else Itv.minus) offset idx_itv in
       L.(debug BufferOverrun Verbose) "@[<v 2>Add condition :@," ;
-      L.(debug BufferOverrun Verbose) "array: %a@," ArrayBlk.pp arr ;
-      L.(debug BufferOverrun Verbose) "  idx: %a@," Itv.pp idx ;
+      L.(debug BufferOverrun Verbose) "array: %a@," ArrayBlk.pp arr_blk ;
+      L.(debug BufferOverrun Verbose) "  idx: %a@," Itv.pp idx_in_blk ;
       L.(debug BufferOverrun Verbose) "@]@." ;
-      match (size, idx) with
+      match (size, idx_in_blk) with
       | NonBottom size, NonBottom idx ->
           let traces = TraceSet.merge ~arr_traces ~idx_traces location in
           PO.ConditionSet.add_array_access pname location ~size ~idx traces cond_set
@@ -199,12 +203,8 @@ module Make (CFG : ProcCfg.S) = struct
 
     let lindex ~array_exp ~index_exp mem pname location cond_set =
       let locs = Sem.eval_locs array_exp mem |> Dom.Val.get_all_locs in
-      let v_arr = Dom.Mem.find_set locs mem in
-      let arr = Dom.Val.get_array_blk v_arr in
-      let arr_traces = Dom.Val.get_traces v_arr in
-      let v_idx = Sem.eval index_exp mem in
-      let idx = Dom.Val.get_itv v_idx in
-      let idx_traces = Dom.Val.get_traces v_idx in
-      array_access ~arr ~arr_traces ~idx ~idx_traces ~is_plus:true pname location cond_set
+      let arr = Dom.Mem.find_set locs mem in
+      let idx = Sem.eval index_exp mem in
+      array_access ~arr ~idx ~is_plus:true pname location cond_set
   end
 end