[cost] Revise hasNext model

Summary:
This diff revises the semantics of hasNext model to add the lengths of
arrays, rather than join them to top.

Reviewed By: ezgicicek

Differential Revision: D17882388

fbshipit-source-id: f5edaedb3

infer/src/bufferoverrun/bufferOverrunModels.ml

@@ -914,8 +914,12 @@ module Collection = struct
       (* Set the size of the iterator to be [0, size], so that range
          will be size of the collection. *)
       let collection_size =
-        eval_collection_length iterator mem
+        let arr_locs = eval_collection_internal_array_locs iterator mem in
-        |> Dom.Val.get_iterator_itv |> Dom.Val.set_itv_updated_by_addition
+        let accum_add arr_loc acc =
+          Dom.Mem.find arr_loc mem |> Dom.Val.array_sizeof |> Itv.plus acc
+        in
+        PowLoc.fold accum_add arr_locs Itv.zero
+        |> Dom.Val.of_itv |> Dom.Val.get_iterator_itv |> Dom.Val.set_itv_updated_by_addition
       in
       model_by_value collection_size ret_id mem
       |> Dom.Mem.add_iterator_has_next_alias ret_id iterator

infer/tests/codetoanalyze/java/performance/ListTest.java

@@ -5,6 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 import com.google.common.base.Objects;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
@@ -63,4 +64,27 @@ class ListTest {
   void call_iterate_elements_linear(List<Integer> l1, List<Integer> l2) {
     iterate_elements_linear(two_lists(l1, l2));
   }
+
+  void iter_multiple_list1_linear(List<Integer> l1, List<Integer> l2) {
+    List<Integer> l;
+    if (unknown_bool) {
+      l = l1;
+    } else {
+      l = l2;
+    }
+    List<Integer> m = new ArrayList<Integer>();
+    for (Integer i : l) {
+      m.add(i);
+    }
+  }
+
+  void iter_multiple_list2_linear(List<Integer> l1, List<Integer> l2) {
+    List<Integer> l;
+    if (unknown_bool) {
+      l = l1;
+    } else {
+      l = l2;
+    }
+    for (Integer i : l) {}
+  }
 }

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

@@ -146,12 +146,14 @@ codetoanalyze/java/performance/JsonUtils.java, libraries.marauder.analytics.util
 codetoanalyze/java/performance/JsonUtils.java, libraries.marauder.analytics.utils.json.JsonUtils.serialize(java.lang.String):java.lang.StringBuilder, 2, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 33 + 65 ⋅ String.toCharArray().length.ub, O(String.toCharArray().length.ub), degree = 1,{String.toCharArray().length.ub},call to void JsonUtils.serialize(StringBuilder,String),call to void JsonUtils.escape(StringBuilder,String),Loop at line 13]
 codetoanalyze/java/performance/JsonUtils.java, libraries.marauder.analytics.utils.json.JsonUtils.serialize(java.lang.StringBuilder,java.lang.String):void, 5, EXPENSIVE_ALLOCATION, no_bucket, ERROR, [with estimated cost String.toCharArray().length.ub, O(String.toCharArray().length.ub), degree = 1,{String.toCharArray().length.ub},call to void JsonUtils.escape(StringBuilder,String),Loop at line 13]
 codetoanalyze/java/performance/JsonUtils.java, libraries.marauder.analytics.utils.json.JsonUtils.serialize(java.lang.StringBuilder,java.lang.String):void, 5, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 24 + 65 ⋅ String.toCharArray().length.ub, O(String.toCharArray().length.ub), degree = 1,{String.toCharArray().length.ub},call to void JsonUtils.escape(StringBuilder,String),Loop at line 13]
-codetoanalyze/java/performance/ListTest.java, ListTest.asList_linear(java.lang.String[]):void, 2, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 7 + 8 ⋅ array.length + 3 ⋅ (array.length + 1), O(array.length), degree = 1,{array.length + 1},Loop at line 41,{array.length},Loop at line 41]
+codetoanalyze/java/performance/ListTest.java, ListTest.asList_linear(java.lang.String[]):void, 2, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 7 + 8 ⋅ array.length + 3 ⋅ (array.length + 1), O(array.length), degree = 1,{array.length + 1},Loop at line 42,{array.length},Loop at line 42]
-codetoanalyze/java/performance/ListTest.java, ListTest.call_iterate_elements_linear(java.util.List,java.util.List):void, 1, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 26 + 5 ⋅ (l2.length + l1.length) + 3 ⋅ (l2.length + l1.length + 1), O((l2.length + l1.length)), degree = 1,{l2.length + l1.length + 1},call to void ListTest.iterate_elements_linear(List),Loop at line 58,{l2.length + l1.length},call to void ListTest.iterate_elements_linear(List),Loop at line 58]
+codetoanalyze/java/performance/ListTest.java, ListTest.call_iterate_elements_linear(java.util.List,java.util.List):void, 1, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 26 + 5 ⋅ (l2.length + l1.length) + 3 ⋅ (l2.length + l1.length + 1), O((l2.length + l1.length)), degree = 1,{l2.length + l1.length + 1},call to void ListTest.iterate_elements_linear(List),Loop at line 59,{l2.length + l1.length},call to void ListTest.iterate_elements_linear(List),Loop at line 59]
-codetoanalyze/java/performance/ListTest.java, ListTest.indexOfImpl_linear(java.util.List,java.lang.Object):int, 2, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 4 + 11 ⋅ list.length + 3 ⋅ (list.length + 1), O(list.length), degree = 1,{list.length + 1},Loop at line 17,{list.length},Loop at line 17]
+codetoanalyze/java/performance/ListTest.java, ListTest.indexOfImpl_linear(java.util.List,java.lang.Object):int, 2, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 4 + 11 ⋅ list.length + 3 ⋅ (list.length + 1), O(list.length), degree = 1,{list.length + 1},Loop at line 18,{list.length},Loop at line 18]
-codetoanalyze/java/performance/ListTest.java, ListTest.iterate_elements_linear(java.util.List):void, 2, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 4 + 5 ⋅ l.length + 3 ⋅ (l.length + 1), O(l.length), degree = 1,{l.length + 1},Loop at line 58,{l.length},Loop at line 58]
+codetoanalyze/java/performance/ListTest.java, ListTest.iter_multiple_list1_linear(java.util.List,java.util.List):void, 8, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 17 + 15 ⋅ (l2.length + l1.length + 1), O((l2.length + l1.length)), degree = 1,{l2.length + l1.length + 1},Loop at line 76]
+codetoanalyze/java/performance/ListTest.java, ListTest.iter_multiple_list2_linear(java.util.List,java.util.List):void, 7, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 14 + 8 ⋅ (l2.length + l1.length) + 3 ⋅ (l2.length + l1.length + 1), O((l2.length + l1.length)), degree = 1,{l2.length + l1.length + 1},Loop at line 88,{l2.length + l1.length},Loop at line 88]
+codetoanalyze/java/performance/ListTest.java, ListTest.iterate_elements_linear(java.util.List):void, 2, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 4 + 5 ⋅ l.length + 3 ⋅ (l.length + 1), O(l.length), degree = 1,{l.length + 1},Loop at line 59,{l.length},Loop at line 59]
 codetoanalyze/java/performance/ListTest.java, ListTest.sort_comparator_nlogn(java.util.List):void, 1, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 8 + people.length × log(people.length), O(people.length × log(people.length)), degree = 1 + 1⋅log,{people.length},Modeled call to List.sort,{people.length},Modeled call to List.sort]
-codetoanalyze/java/performance/ListTest.java, ListTest.sublist(java.util.List):void, 2, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 11 + 8 ⋅ (filesList.length - 1) + 3 ⋅ filesList.length, O(filesList.length), degree = 1,{filesList.length},Loop at line 31,{filesList.length - 1},Loop at line 31]
+codetoanalyze/java/performance/ListTest.java, ListTest.sublist(java.util.List):void, 2, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 11 + 8 ⋅ (filesList.length - 1) + 3 ⋅ filesList.length, O(filesList.length), degree = 1,{filesList.length},Loop at line 32,{filesList.length - 1},Loop at line 32]
 codetoanalyze/java/performance/Loops.java, codetoanalyze.java.performance.Loops.charsequence_length_linear(java.lang.CharSequence):void, 1, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 2 + 5 ⋅ seq.length + 3 ⋅ (seq.length + 1), O(seq.length), degree = 1,{seq.length + 1},Loop at line 115,{seq.length},Loop at line 115]
 codetoanalyze/java/performance/Loops.java, codetoanalyze.java.performance.Loops.do_while_independent_of_p(int):int, 3, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 250, O(1), degree = 0]
 codetoanalyze/java/performance/Loops.java, codetoanalyze.java.performance.Loops.dumb0(long[],int):void, 1, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 2 + 25 ⋅ (length - 1), O(length), degree = 1,{length - 1},Loop at line 44]