[pulse] Brush up List.set() model

Summary: We mistakenly invalidated the set element which causes spurious vector invalidation errors. Instead, we should modify it without any invalidation.

Reviewed By: jvillard

Differential Revision: D21521943

fbshipit-source-id: 67963967e

infer/src/pulse/PulseModels.ml

@@ -562,17 +562,18 @@ module StdVector = struct
 end
 
 module JavaCollection = struct
-  let set coll index new_elem : model =
+  (* modifies arr[index]-> old_elem to arr[index]-> new_elem and returns old_elem *)
+  let set coll (index, _) (new_elem, new_elem_hist) : model =
    fun _ ~callee_procname:_ location ~ret astate ->
     let event = ValueHistory.Call {f= Model "Collection.set"; location; in_call= []} in
-    let* astate, ((old_addr, old_hist) as old_elem) =
+    let* astate, arr = GenericArrayBackedCollection.eval location coll astate in
-      GenericArrayBackedCollection.element location coll (fst index) astate
+    let* astate, (old_addr, old_hist) =
+      GenericArrayBackedCollection.element location coll index astate
     in
     let+ astate =
-      PulseOperations.write_deref location ~ref:new_elem
+      PulseOperations.write_arr_index location ~ref:arr ~index
-        ~obj:(old_addr, ValueHistory.Assignment location :: old_hist)
+        ~obj:(new_elem, event :: new_elem_hist)
         astate
-      >>= PulseOperations.invalidate_access location (StdVector Assign) old_elem Dereference
     in
     let astate = PulseOperations.write_id (fst ret) (old_addr, event :: old_hist) astate in
     [ExecutionDomain.ContinueProgram astate]

infer/tests/codetoanalyze/java/impurity/PurityModeled.java

@@ -84,6 +84,11 @@ class PurityModeled {
     list.set(0, "e");
   }
 
+  void call_set_impure(ArrayList<String> list) {
+    list_set_impure(list);
+    list_set_impure(list);
+  }
+
   // Pulse can only widen a fixed number of times, hence it thinks
   // that the exit of the loop never reaches and results in empty
   // post.

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

@@ -16,13 +16,14 @@ codetoanalyze/java/impurity/Localities.java, Localities.modify_first_el_impure(j
 codetoanalyze/java/impurity/Localities.java, Localities.modify_via_call_impure(java.util.ArrayList):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void Localities.modify_via_call_impure(ArrayList),when calling `void Localities$Foo.inc_impure()` here,parameter `list` modified here]
 codetoanalyze/java/impurity/Localities.java, Localities.newHashCode_impure():int, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function int Localities.newHashCode_impure(),call to skipped function int Object.hashCode() occurs here]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.append_impure(java.lang.StringBuilder):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.append_impure(StringBuilder),parameter `strBuilder` modified here]
+codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.call_set_impure(java.util.ArrayList):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.call_set_impure(ArrayList),when calling `void PurityModeled.list_set_impure(ArrayList)` here,parameter `list` modified here]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.call_timing_symb_impure(int):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.call_timing_symb_impure(int),when calling `void PurityModeled.timing_call_in_loop_symb_impure(int)` here,call to skipped function long System.nanoTime() occurs here]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.call_timing_symb_unrelated_impure(int,int):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.call_timing_symb_unrelated_impure(int,int),when calling `void PurityModeled.timing_call_in_loop_symb_impure(int)` here,call to skipped function long System.nanoTime() occurs here]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.call_write_impure():void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.call_write_impure(),when calling `void PurityModeled.write_impure()` here,call to skipped function void PrintStream.write(byte[],int,int) occurs here]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.constant_loop_pure_FP():void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.constant_loop_pure_FP() with empty pulse summary]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.list_add_impure(java.util.ArrayList):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.list_add_impure(ArrayList),parameter `list` modified here]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.list_addall_impure(java.util.ArrayList,java.util.ArrayList):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.list_addall_impure(ArrayList,ArrayList),parameter `list1` modified here]
-codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.list_set_impure(java.util.ArrayList):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.list_set_impure(ArrayList),parameter `list` was potentially invalidated by `std::vector::assign()` here]
+codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.list_set_impure(java.util.ArrayList):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.list_set_impure(ArrayList),parameter `list` modified here]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.math_random_impure():double, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function double PurityModeled.math_random_impure(),call to skipped function double Math.random() occurs here]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.math_random_in_loop_impure(int):int, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function int PurityModeled.math_random_in_loop_impure(int),when calling `void PurityModeled.call_write_impure()` here,when calling `void PurityModeled.write_impure()` here,call to skipped function void PrintStream.write(byte[],int,int) occurs here,call to skipped function double Math.random() occurs here]
 codetoanalyze/java/impurity/PurityModeled.java, PurityModeled.nested_remove_impure(java.util.ArrayList):void, 0, IMPURE_FUNCTION, no_bucket, ERROR, [Impure function void PurityModeled.nested_remove_impure(ArrayList),parameter `list` modified here]