1 /*
2  * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.
8  *
9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 package gc.g1.unloading.bytecode;
24 
25 import java.util.HashMap;
26 import java.util.Map;
27 import java.util.Random;
28 
29 import vm.share.InMemoryJavaCompiler;
30 
31 /**
32  * BytecodeFactory that employs in memory compilation.
33  */
34 public class BytecodeGeneratorFactory implements BytecodeFactory {
35 
36     private Random random;
37 
38     private SourceGenerator sourceGenerator;
39 
BytecodeGeneratorFactory(long seed)40     public BytecodeGeneratorFactory(long seed) {
41         random = new Random(seed);
42         sourceGenerator = new SourceGenerator(random.nextLong());
43     }
44 
45     @Override
createBytecode(String className)46     public Bytecode createBytecode(String className) {
47         Map<String, CharSequence> sources = new HashMap<String, CharSequence>();
48         sources.put(className, sourceGenerator.generateSource(className,
49                 "public static void main() { System.out.println(\"From main method in in-mem-compiled code " + random.nextGaussian() +
50                         " + str_bytesToReplace0 str_bytesToReplace1\"); }\n " +
51                         "public static int methodForCompilation(Object object) { int i = object.hashCode(); i = i * 2000 / 1994 + 153; return i; }\n"));
52         byte[] bytecode = InMemoryJavaCompiler.compile(sources).values().iterator().next();
53         return new Bytecode(className, bytecode);
54     }
55 
56 }
57