[cost] The first cost model is a log

Reviewed By: ezgicicek

Differential Revision: D13175881

fbshipit-source-id: 7718bdf0d

infer/src/bufferoverrun/polynomials.ml

@@ -13,8 +13,6 @@ open Ints
 module DegreeKind = struct
   type t = Linear | Log [@@deriving compare]
 
-  let[@warning "-32"] _i_know_log_isn't_used_for_now = Log
-
   let compute d i =
     match d with
     | Linear ->
@@ -421,9 +419,9 @@ module NonNegativePolynomial = struct
 
   let of_int_exn i = NonTop (NonNegativeNonTopPolynomial.of_int_exn i)
 
-  let of_non_negative_bound b =
+  let of_non_negative_bound ?(degree_kind = DegreeKind.Linear) b =
     b
-    |> NonNegativeBoundWithDegreeKind.make DegreeKind.Linear
+    |> NonNegativeBoundWithDegreeKind.make degree_kind
     |> NonNegativeBoundWithDegreeKind.classify |> NonNegativeNonTopPolynomial.of_valclass
 
 

infer/src/bufferoverrun/polynomials.mli

@@ -8,6 +8,10 @@
 open! IStd
 module Bound = Bounds.Bound
 
+module DegreeKind : sig
+  type t = Linear | Log
+end
+
 module Degree : sig
   type t [@@deriving compare]
 
@@ -36,7 +40,7 @@ module NonNegativePolynomial : sig
 
   val is_one : t -> bool
 
-  val of_non_negative_bound : Bounds.NonNegativeBound.t -> t
+  val of_non_negative_bound : ?degree_kind:DegreeKind.t -> Bounds.NonNegativeBound.t -> t
 
   val plus : t -> t -> t
 

infer/src/checkers/cost.ml

@@ -66,6 +66,10 @@ module TransferFunctionsNodesBasicCost = struct
       match instr with
       | Sil.Call (_, Exp.Const (Const.Cfun callee_pname), params, _, _) ->
           let callee_cost =
+            match CostModels.Call.dispatch () callee_pname params with
+            | Some model ->
+                model inferbo_mem
+            | None -> (
               match Payload.read pdesc callee_pname with
               | Some {post= callee_cost} ->
                   if BasicCost.is_symbolic callee_cost then
@@ -73,7 +77,7 @@ module TransferFunctionsNodesBasicCost = struct
                       ~callee_pname ~params ~callee_cost
                   else callee_cost
               | None ->
-                cost_atomic_instruction
+                  cost_atomic_instruction )
           in
           CostDomain.NodeInstructionToCostMap.add key callee_cost astate
       | Sil.Load _ | Sil.Store _ | Sil.Call _ | Sil.Prune _ ->

infer/src/checkers/costModels.ml

@@ -0,0 +1,40 @@
+(*
+ * Copyright (c) 2018-present, Facebook, Inc.
+ *
+ * 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 BasicCost = CostDomain.BasicCost
+
+type model = BufferOverrunDomain.Mem.t -> BasicCost.t
+
+module Collections = struct
+  let eval_collection_length coll_exp inferbo_mem =
+    let upper_bound =
+      let itv =
+        BufferOverrunModels.Collection.eval_collection_length coll_exp inferbo_mem
+        |> BufferOverrunDomain.Val.get_itv
+      in
+      match itv with Bottom -> Bounds.Bound.PInf | NonBottom itv_pure -> Itv.ItvPure.ub itv_pure
+    in
+    Bounds.NonNegativeBound.of_bound upper_bound
+
+
+  let n_log_n b =
+    let n = BasicCost.of_non_negative_bound b in
+    let log_n = BasicCost.of_non_negative_bound ~degree_kind:Polynomials.DegreeKind.Log b in
+    BasicCost.mult n log_n
+
+
+  let sort coll_exp inferbo_mem =
+    let length = eval_collection_length coll_exp inferbo_mem in
+    n_log_n length
+end
+
+module Call = struct
+  let dispatch : (unit, model) ProcnameDispatcher.Call.dispatcher =
+    let open ProcnameDispatcher.Call in
+    make_dispatcher [-"java.util.Collections" &:: "sort" $ capt_exp $--> Collections.sort]
+end

infer/tests/build_systems/differential_of_costs_report/costs_summary.json.exp

@@ -1 +1 @@
-{"top":{"current":1,"previous":0},"zero":{"current":0,"previous":0},"degrees":[{"degree":0,"current":3,"previous":2},{"degree":100,"current":1,"previous":1},{"degree":200,"current":0,"previous":1}]}
+{"top":{"current":1,"previous":0},"zero":{"current":0,"previous":0},"degrees":[{"degree":0,"current":3,"previous":2},{"degree":100,"current":1,"previous":2},{"degree":101,"current":2,"previous":0},{"degree":200,"current":0,"previous":2}]}

infer/tests/build_systems/differential_of_costs_report/fixed.exp

@@ -0,0 +1 @@
+PERFORMANCE_VARIATION, no_bucket, src/DiffExample.java, DiffExample.f6(java.util.ArrayList):void, 0

infer/tests/build_systems/differential_of_costs_report/introduced.exp

@@ -1,2 +1,3 @@
 INFINITE_EXECUTION_TIME_CALL, no_bucket, src/DiffExample.java, DiffExample.f1(int):void, 0
 PERFORMANCE_VARIATION, no_bucket, src/DiffExample.java, DiffExample.f4(int):int, 0
+PERFORMANCE_VARIATION, no_bucket, src/DiffExample.java, DiffExample.f5(java.util.ArrayList):void, 0

infer/tests/build_systems/differential_of_costs_report/src/DiffExample.java.current

@@ -5,6 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import java.util.ArrayList;
+
 // This class has the following costs:
 // 1 bottom (zero), 2 constant, 1 linear, 1 top
 // constructor: constant
@@ -12,6 +14,8 @@
 // f2: bottom (zero)
 // f3: constant
 // f4: linear
+// f5: n log n
+// f6: n log n
 
 public class DiffExample {
 
@@ -41,4 +45,14 @@ public class DiffExample {
         }
         return 0;
     }
+
+    // cost: n log n
+    private void f5(ArrayList<Integer> list) {
+      java.util.Collections.sort(list);
+    }
+
+    // cost: n log n
+    private void f6(ArrayList<Integer> list) {
+      f5(list);
+    }
 }

infer/tests/build_systems/differential_of_costs_report/src/DiffExample.java.previous

@@ -11,6 +11,8 @@
 // f1: linear
 // f2: quadratic
 // f4: constant
+// f5: linear
+// f6: quadratic
 
 public class DiffExample {
     // cost: linear
@@ -32,4 +34,14 @@ public class DiffExample {
         int i = 1;
         return i + k;
     }
+
+    // cost: linear
+    private static void f5(int n) {
+        f1(n);
+    }
+
+    // cost: quadratic
+    private static void f6(int n) {
+        f2(n);
+    }
 }

infer/tests/codetoanalyze/java/performance/ArrayListTest.java

@@ -197,4 +197,12 @@ public class ArrayListTest {
     }
     return true;
   }
+
+  public static void sortArrayList(ArrayList<Integer> list) {
+    java.util.Collections.sort(list);
+  }
+
+  private static void call_sortArrayList(ArrayList<Integer> list) {
+    sortArrayList(list);
+  }
 }

infer/tests/codetoanalyze/java/performance/issues.exp

@@ -25,6 +25,7 @@ codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.arraylist_remov
 codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.arraylist_remove_overrun_bad():void, 3, BUFFER_OVERRUN_L1, no_bucket, ERROR, [<Length trace>,Array declaration,Through,Array access: Offset: 1 Size: 1]
 codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.arraylist_set_overrun_bad():void, 3, BUFFER_OVERRUN_L1, no_bucket, ERROR, [<Length trace>,Array declaration,Through,Array access: Offset: 1 Size: 1]
 codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.arraylist_set_underrun_bad():void, 2, BUFFER_OVERRUN_L1, no_bucket, ERROR, [<Length trace>,Array declaration,Array access: Offset: 0 Size: 0]
+codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.call_sortArrayList(java.util.ArrayList):void, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 4 + list.length.ub × log(list.length.ub), degree = 1 + 1⋅log]
 codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.iterate_over_arraylist(java.util.ArrayList):void, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 7 + 5 ⋅ list.length.ub, degree = 1]
 codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.iterate_over_arraylist(java.util.ArrayList):void, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 6 + 5 ⋅ list.length.ub, degree = 1]
 codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.iterate_over_arraylist_shortcut_FP(java.util.ArrayList):boolean, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 5 + 13 ⋅ (list.length.ub - 1) + 2 ⋅ (list.length.ub - 1) × (-Integer.intValue().lb + 11) + 4 ⋅ list.length.ub × (-Integer.intValue().lb + 11), degree = 2]
@@ -41,6 +42,7 @@ codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.iterate_while_h
 codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.iterate_while_has_next(java.util.ArrayList):void, 4, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 5 + 12 ⋅ (list.length.ub - 1) + 4 ⋅ list.length.ub, degree = 1]
 codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.iterate_with_iterator(java.util.ArrayList):void, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 6 + 9 ⋅ (list.length.ub - 1) + 4 ⋅ list.length.ub, degree = 1]
 codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.iterate_with_iterator(java.util.ArrayList):void, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 5 + 9 ⋅ (list.length.ub - 1) + 4 ⋅ list.length.ub, degree = 1]
+codetoanalyze/java/performance/ArrayListTest.java, ArrayListTest.sortArrayList(java.util.ArrayList):void, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 2 + list.length.ub × log(list.length.ub), degree = 1 + 1⋅log]
 codetoanalyze/java/performance/Break.java, codetoanalyze.java.performance.Break.break_constant(int):int, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 10 + 7 ⋅ p.ub, degree = 1]
 codetoanalyze/java/performance/Break.java, codetoanalyze.java.performance.Break.break_loop(int,int):int, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 3 + 7 ⋅ p.ub, degree = 1]
 codetoanalyze/java/performance/Break.java, codetoanalyze.java.performance.Break.break_loop(int,int):int, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 2 + 7 ⋅ p.ub, degree = 1]