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1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 import java.lang.reflect.Method;
18 
19 public class Main  {
20 
21   class MyClassA {}
22   class MyClassB extends MyClassA {}
23 
main(String[] args)24   public static void main(String[] args) throws Exception {
25     testReferenceTypePropagation();
26     invokeTestInliner();
27   }
28 
29   // Reference type propagation (RTP) used to assume that if a class is final,
30   // then the type must be exact. This does not hold for arrays which are always
31   // final, i.e. not extendable, but may be assigned to from values of the
32   // components type subclasses.
33 
testReferenceTypePropagation()34   public static void testReferenceTypePropagation() throws Exception {
35     boolean expectTrue;
36 
37     // Bug #1: RTP would set the type of `array` to exact Object[]. Instruction
38     // simplifier would then simplify the instanceof to `false`.
39     Object[] array = $noinline$getArray();
40     expectTrue = array instanceof MyClassA[];
41     if (!expectTrue) {
42       throw new Exception("Incorrect type check.");
43     }
44 
45     // Bug #2: This is the true-branch of the instanceof above. The bound type
46     // for `array` would be again set to exact MyClassA[] and incorrectly
47     // simplify the second instanceof to `false`.
48     expectTrue = array instanceof MyClassB[];
49     if (!expectTrue) {
50       throw new Exception("Incorrect type bound.");
51     }
52   }
53 
invokeTestInliner()54   public static void invokeTestInliner() throws Exception {
55     Class<?> c = Class.forName("TestCase");
56     Method m = c.getMethod("testInliner");
57     m.invoke(null);
58   }
59 
$noinline$getArray()60   public static Object[] $noinline$getArray() {
61     if (doThrow) throw new Error();
62     return new MyClassB[2];
63   }
64 
65   static boolean doThrow = false;
66 }
67