/*

 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

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 */

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.util.List;

import java.util.Set;

import java.util.stream.Collectors;

import java.lang.StackWalker.StackFrame;

public class LocalLongHelper {

    static StackWalker sw;

    static Method longValue;

    static Method getLocals;

    static Class<?> primitiveValueClass;

    static Method primitiveSize;

    static Method getMethodType;

    static Field memberName;

    static Field offset;

    public static void main(String[] args) throws Throwable {

        setupReflectionStatics();

        new LocalLongHelper().longArg(0xC0FFEE, 0x1234567890ABCDEFL);

    }

    // locals[2] contains the unused slot of the long argument.

    public long longArg(int i, long l) throws Throwable {

        List<StackFrame> frames = sw.walk(s -> s.collect(Collectors.toList()));

        Object[] locals = (Object[]) getLocals.invoke(frames.get(0));

        if (8 == (int) primitiveSize.invoke(locals[2])) { // Only test 64-bit

            long locals_2 = (long) longValue.invoke(locals[2]);

            if (locals_2 != 0){

                throw new RuntimeException("Expected locals_2 == 0");

            }

        }

        return l; // Don't want l to become a dead var

    }

    private static void setupReflectionStatics() throws Throwable {

        Class<?> liveStackFrameClass = Class.forName("java.lang.LiveStackFrame");

        primitiveValueClass = Class.forName("java.lang.LiveStackFrame$PrimitiveSlot");

        getLocals = liveStackFrameClass.getDeclaredMethod("getLocals");

        getLocals.setAccessible(true);

        longValue = primitiveValueClass.getDeclaredMethod("longValue");

        longValue.setAccessible(true);

        Class<?> stackFrameInfoClass = Class.forName("java.lang.StackFrameInfo");

        memberName = stackFrameInfoClass.getDeclaredField("memberName");

        memberName.setAccessible(true);

        offset = stackFrameInfoClass.getDeclaredField("bci");

        offset.setAccessible(true);

        getMethodType = Class.forName("java.lang.invoke.MemberName").getDeclaredMethod("getMethodType");

        getMethodType.setAccessible(true);

        Class<?> extendedOptionClass = Class.forName("java.lang.StackWalker$ExtendedOption");

        Method ewsNI = StackWalker.class.getDeclaredMethod("newInstance", Set.class, extendedOptionClass);

        ewsNI.setAccessible(true);

        Field f = extendedOptionClass.getDeclaredField("LOCALS_AND_OPERANDS");

        f.setAccessible(true);

        Object localsAndOperandsOption = f.get(null);

        primitiveSize = primitiveValueClass.getDeclaredMethod("size");

        primitiveSize.setAccessible(true);

        sw = (StackWalker) ewsNI.invoke(null, java.util.Collections.emptySet(), localsAndOperandsOption);

    }

}