1/*
2 * Copyright (c) 2016, 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
24import java.lang.reflect.Field;
25import java.lang.reflect.Method;
26import java.util.List;
27import java.util.Set;
28import java.util.stream.Collectors;
29import java.lang.StackWalker.StackFrame;
30
31public class LocalLongHelper {
32    static StackWalker sw;
33    static Method longValue;
34    static Method getLocals;
35    static Class<?> primitiveValueClass;
36    static Method primitiveSize;
37    static Method getMethodType;
38    static Field memberName;
39    static Field offset;
40
41    public static void main(String[] args) throws Throwable {
42        setupReflectionStatics();
43        new LocalLongHelper().longArg(0xC0FFEE, 0x1234567890ABCDEFL);
44    }
45
46    // locals[2] contains the unused slot of the long argument.
47    public long longArg(int i, long l) throws Throwable {
48        List<StackFrame> frames = sw.walk(s -> s.collect(Collectors.toList()));
49        Object[] locals = (Object[]) getLocals.invoke(frames.get(0));
50
51        if (8 == (int) primitiveSize.invoke(locals[2])) { // Only test 64-bit
52            long locals_2 = (long) longValue.invoke(locals[2]);
53            if (locals_2 != 0){
54                throw new RuntimeException("Expected locals_2 == 0");
55            }
56        }
57        return l; // Don't want l to become a dead var
58    }
59
60    private static void setupReflectionStatics() throws Throwable {
61        Class<?> liveStackFrameClass = Class.forName("java.lang.LiveStackFrame");
62        primitiveValueClass = Class.forName("java.lang.LiveStackFrame$PrimitiveSlot");
63
64        getLocals = liveStackFrameClass.getDeclaredMethod("getLocals");
65        getLocals.setAccessible(true);
66
67        longValue = primitiveValueClass.getDeclaredMethod("longValue");
68        longValue.setAccessible(true);
69
70        Class<?> stackFrameInfoClass = Class.forName("java.lang.StackFrameInfo");
71        memberName = stackFrameInfoClass.getDeclaredField("memberName");
72        memberName.setAccessible(true);
73        offset = stackFrameInfoClass.getDeclaredField("bci");
74        offset.setAccessible(true);
75        getMethodType = Class.forName("java.lang.invoke.MemberName").getDeclaredMethod("getMethodType");
76        getMethodType.setAccessible(true);
77
78        Class<?> extendedOptionClass = Class.forName("java.lang.StackWalker$ExtendedOption");
79        Method ewsNI = StackWalker.class.getDeclaredMethod("newInstance", Set.class, extendedOptionClass);
80        ewsNI.setAccessible(true);
81        Field f = extendedOptionClass.getDeclaredField("LOCALS_AND_OPERANDS");
82        f.setAccessible(true);
83        Object localsAndOperandsOption = f.get(null);
84
85        primitiveSize = primitiveValueClass.getDeclaredMethod("size");
86        primitiveSize.setAccessible(true);
87        sw = (StackWalker) ewsNI.invoke(null, java.util.Collections.emptySet(), localsAndOperandsOption);
88    }
89}
90