/*

 * Copyright (c) 2017, 2019, 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

 * questions.

 */

package org.graalvm.compiler.hotspot.meta;

import static org.graalvm.compiler.hotspot.GraalHotSpotVMConfig.INJECTED_VMCONFIG;

import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.doingUnsafeAccessOffset;

import org.graalvm.compiler.api.replacements.ClassSubstitution;

import org.graalvm.compiler.api.replacements.MethodSubstitution;

import org.graalvm.compiler.hotspot.HotSpotBackend;

import org.graalvm.compiler.hotspot.nodes.CurrentJavaThreadNode;

import org.graalvm.compiler.nodes.ComputeObjectAddressNode;

import org.graalvm.compiler.serviceprovider.JavaVersionUtil;

import org.graalvm.compiler.word.Word;

import jdk.internal.vm.compiler.word.LocationIdentity;

import jdk.internal.vm.compiler.word.WordFactory;

@ClassSubstitution(className = {"jdk.internal.misc.Unsafe", "sun.misc.Unsafe"})

public class HotSpotUnsafeSubstitutions {

    public static final String copyMemoryName = JavaVersionUtil.JAVA_SPEC <= 8 ? "copyMemory" : "copyMemory0";

    @SuppressWarnings("unused")

    @MethodSubstitution(isStatic = false)

    static void copyMemory(Object receiver, Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes) {

        Word srcAddr = WordFactory.unsigned(ComputeObjectAddressNode.get(srcBase, srcOffset));

        Word dstAddr = WordFactory.unsigned(ComputeObjectAddressNode.get(destBase, destOffset));

        Word size = WordFactory.signed(bytes);

        HotSpotBackend.unsafeArraycopy(srcAddr, dstAddr, size);

    }

    @SuppressWarnings("unused")

    @MethodSubstitution(value = "copyMemory", isStatic = false)

    static void copyMemoryGuarded(Object receiver, Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes) {

        Word srcAddr = WordFactory.unsigned(ComputeObjectAddressNode.get(srcBase, srcOffset));

        Word dstAddr = WordFactory.unsigned(ComputeObjectAddressNode.get(destBase, destOffset));

        Word size = WordFactory.signed(bytes);

        Word javaThread = CurrentJavaThreadNode.get();

        int offset = doingUnsafeAccessOffset(INJECTED_VMCONFIG);

        LocationIdentity any = LocationIdentity.any();

        /* Set doingUnsafeAccess to guard and handle unsafe memory access failures */

        javaThread.writeByte(offset, (byte) 1, any);

        HotSpotBackend.unsafeArraycopy(srcAddr, dstAddr, size);

        /* Reset doingUnsafeAccess */

        javaThread.writeByte(offset, (byte) 0, any);

    }

}