From b4a22a5bdd09e4ccc04b6c1504c1158f63b3cc38 Mon Sep 17 00:00:00 2001
From: Nikos Gorogiannis <nikosgorogiannis@fb.com>
Date: Sat, 26 Jan 2019 02:30:46 -0800
Subject: [PATCH] [classloads] prune and multidimensional arrays

Reviewed By: ezgicicek

Differential Revision: D13818684

fbshipit-source-id: 8e5289f8f
---
 infer/src/concurrency/classLoads.ml           | 18 ++++++++++-----
 .../codetoanalyze/java/classloads/Arrays.java |  4 ++++
 .../codetoanalyze/java/classloads/Prune.java  | 22 +++++++++++++++++++
 3 files changed, 39 insertions(+), 5 deletions(-)
 create mode 100644 infer/tests/codetoanalyze/java/classloads/Prune.java

diff --git a/infer/src/concurrency/classLoads.ml b/infer/src/concurrency/classLoads.ml
index bfad3077f..0e22c5294 100644
--- a/infer/src/concurrency/classLoads.ml
+++ b/infer/src/concurrency/classLoads.ml
@@ -14,8 +14,6 @@ module L = Logging
 
 (* TODO 
   - catch / throw with exception classes 
-  - multidimensional arrays (multinewarray) ? 
-  - prune
 *)
 
 module Payload = SummaryPayload.Make (struct
@@ -57,6 +55,14 @@ let load_type proc_desc tenv loc (typ : Typ.t) astate =
       astate
 
 
+let rec load_array proc_desc tenv loc (typ : Typ.t) astate =
+  match typ with
+  | {desc= Tarray {elt}} ->
+      load_array proc_desc tenv loc elt astate
+  | _ ->
+      load_type proc_desc tenv loc typ astate
+
+
 let rec add_loads_of_exp proc_desc tenv loc (exp : Exp.t) astate =
   match exp with
   | Const (Cclass class_ident) ->
@@ -65,8 +71,8 @@ let rec add_loads_of_exp proc_desc tenv loc (exp : Exp.t) astate =
       let class_name = Typ.JavaClass class_str in
       load_class proc_desc tenv loc astate class_name
   | Sizeof {typ= {desc= Tarray {elt}}} ->
-      (* anewarray *)
-      load_type proc_desc tenv loc elt astate
+      (* anewarray / multinewarray *)
+      load_array proc_desc tenv loc elt astate
   | Sizeof {typ; subtype} when Subtype.is_cast subtype || Subtype.is_instof subtype ->
       (* checkcast / instanceof *)
       load_type proc_desc tenv loc typ astate
@@ -88,7 +94,9 @@ let exec_instr pdesc tenv astate _ (instr : Sil.instr) =
       (* invokeinterface / invokespecial / invokestatic / invokevirtual / new *)
       List.fold args ~init:astate ~f:(fun acc (exp, _) -> add_loads_of_exp pdesc tenv loc exp acc)
       |> do_call pdesc callee loc
-  | Load (_, exp, _, loc) ->
+  | Load (_, exp, _, loc) | Prune (exp, loc, _, _) ->
+      (* NB the java frontend seems to always translate complex guards into a sequence of 
+         instructions plus a prune on logical vars only.  So the below is only for completeness. *)
       add_loads_of_exp pdesc tenv loc exp astate
   | Store (e1, _, e2, loc) ->
       add_loads_of_exp pdesc tenv loc e1 astate |> add_loads_of_exp pdesc tenv loc e2
diff --git a/infer/tests/codetoanalyze/java/classloads/Arrays.java b/infer/tests/codetoanalyze/java/classloads/Arrays.java
index f75c3b9df..c6cf01f43 100644
--- a/infer/tests/codetoanalyze/java/classloads/Arrays.java
+++ b/infer/tests/codetoanalyze/java/classloads/Arrays.java
@@ -14,6 +14,8 @@ class Arrays {
     ArraysA[] arrayA = new ArraysA[10];
 
     System.out.println(ArraysF.foo()[0]);
+
+    ArraysG[][] arrayG = new ArraysG[10][10];
   }
 }
 
@@ -34,3 +36,5 @@ class ArraysF {
     return new ArraysE[10];
   }
 }
+
+class ArraysG {}
diff --git a/infer/tests/codetoanalyze/java/classloads/Prune.java b/infer/tests/codetoanalyze/java/classloads/Prune.java
new file mode 100644
index 000000000..2e2e009ea
--- /dev/null
+++ b/infer/tests/codetoanalyze/java/classloads/Prune.java
@@ -0,0 +1,22 @@
+/*
+ * 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.
+ */
+
+class Prune {
+  public static void main(String args[]) {
+    if (PruneA.f == 0) {
+      System.out.println(PruneB.g < 0);
+    }
+  }
+}
+
+class PruneA {
+  static int f;
+}
+
+class PruneB {
+  static int g;
+}