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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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
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package com.oracle.svm.core.code;

import static com.oracle.svm.core.util.PointerUtils.roundUp;

import org.graalvm.compiler.api.replacements.Fold;
import org.graalvm.nativeimage.CurrentIsolate;
import org.graalvm.nativeimage.ImageSingletons;
import org.graalvm.word.Pointer;
import org.graalvm.word.PointerBase;
import org.graalvm.word.UnsignedWord;
import org.graalvm.word.WordFactory;

import com.oracle.svm.core.Isolates;
import com.oracle.svm.core.Uninterruptible;
import com.oracle.svm.core.heap.Heap;

public abstract class DynamicMethodAddressResolutionHeapSupport {

    @Fold
    public static boolean isEnabled() {
        return ImageSingletons.contains(DynamicMethodAddressResolutionHeapSupport.class);
    }

    @Fold
    public static DynamicMethodAddressResolutionHeapSupport get() {
        return ImageSingletons.lookup(DynamicMethodAddressResolutionHeapSupport.class);
    }

    public abstract int initialize();

    public abstract UnsignedWord getRequiredPreHeapMemoryInBytes();

    public abstract int install(Pointer address);

    @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
    public UnsignedWord getDynamicMethodAddressResolverPreHeapMemoryBytes() {
        UnsignedWord requiredPreHeapMemoryInBytes = getRequiredPreHeapMemoryInBytes();
        /* Ensure there is enough space to properly align the heap */
        UnsignedWord heapAlignment = WordFactory.unsigned(Heap.getHeap().getPreferredAddressSpaceAlignment());
        return roundUp((PointerBase) requiredPreHeapMemoryInBytes, heapAlignment);
    }

    @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
    public Pointer getPreHeapMappingStartAddress() {
        UnsignedWord heapBase = (UnsignedWord) Isolates.getHeapBase(CurrentIsolate.getIsolate());
        return (Pointer) heapBase.subtract(getRequiredPreHeapMemoryInBytes());
    }

}
