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 dalvik.system.VMDebug;
18 import java.io.IOException;
19 import java.lang.ref.PhantomReference;
20 import java.lang.ref.ReferenceQueue;
21 import java.lang.ref.WeakReference;
22 import libcore.util.NativeAllocationRegistry;
23 
24 /**
25  * Program used to create a heap dump for test purposes.
26  */
27 public class Main {
28   // Keep a reference to the DumpedStuff instance so that it is not garbage
29   // collected before we take the heap dump.
30   public static DumpedStuff stuff;
31 
32   // We will take a heap dump that includes a single instance of this
33   // DumpedStuff class. Objects stored as fields in this class can be easily
34   // found in the hprof dump by searching for the instance of the DumpedStuff
35   // class and reading the desired field.
36   public static class DumpedStuff {
37     public String basicString = "hello, world";
38     public char[] charArray = "char thing".toCharArray();
39     public String nullString = null;
40     public Object anObject = new Object();
41     public ReferenceQueue<Object> referenceQueue = new ReferenceQueue<Object>();
42     public PhantomReference aPhantomReference = new PhantomReference(anObject, referenceQueue);
43     public WeakReference aWeakReference = new WeakReference(anObject, referenceQueue);
44     public byte[] bigArray;
45 
DumpedStuff()46     DumpedStuff() {
47       int N = 1000000;
48       bigArray = new byte[N];
49       for (int i = 0; i < N; i++) {
50         bigArray[i] = (byte)((i*i) & 0xFF);
51       }
52 
53       NativeAllocationRegistry registry = new NativeAllocationRegistry(
54           Main.class.getClassLoader(), 0x12345, 42);
55       registry.registerNativeAllocation(anObject, 0xABCDABCD);
56     }
57   }
58 
main(String[] args)59   public static void main(String[] args) throws IOException {
60     if (args.length < 1) {
61       System.err.println("no output file specified");
62       return;
63     }
64     String file = args[0];
65 
66     // Allocate the instance of DumpedStuff.
67     stuff = new DumpedStuff();
68 
69     // Take a heap dump that will include that instance of DumpedStuff.
70     System.err.println("Dumping hprof data to " + file);
71     VMDebug.dumpHprofData(file);
72   }
73 }
74