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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
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package jdk.vm.ci.hotspot.aarch64;

import static java.util.Collections.emptyMap;
import static jdk.vm.ci.common.InitTimer.timer;

import java.util.EnumSet;
import java.util.Map;

import jdk.vm.ci.aarch64.AArch64;
import jdk.vm.ci.aarch64.AArch64.CPUFeature;
import jdk.vm.ci.code.Architecture;
import jdk.vm.ci.code.RegisterConfig;
import jdk.vm.ci.code.TargetDescription;
import jdk.vm.ci.code.stack.StackIntrospection;
import jdk.vm.ci.common.InitTimer;
import jdk.vm.ci.hotspot.HotSpotCodeCacheProvider;
import jdk.vm.ci.hotspot.HotSpotConstantReflectionProvider;
import jdk.vm.ci.hotspot.HotSpotJVMCIBackendFactory;
import jdk.vm.ci.hotspot.HotSpotJVMCIRuntime;
import jdk.vm.ci.hotspot.HotSpotMetaAccessProvider;
import jdk.vm.ci.hotspot.HotSpotStackIntrospection;
import jdk.vm.ci.meta.ConstantReflectionProvider;
import jdk.vm.ci.runtime.JVMCIBackend;

public class AArch64HotSpotJVMCIBackendFactory implements HotSpotJVMCIBackendFactory {

    private static EnumSet<AArch64.CPUFeature> computeFeatures(AArch64HotSpotVMConfig config) {
        // Configure the feature set using the HotSpot flag settings.
        Map<String, Long> constants = config.getStore().getConstants();
        return HotSpotJVMCIBackendFactory.convertFeatures(CPUFeature.class, constants, idx -> 1L << idx, _ -> config.vmVersionFeatures, emptyMap());
    }

    private static TargetDescription createTarget(AArch64HotSpotVMConfig config) {
        final int stackFrameAlignment = 16;
        final int implicitNullCheckLimit = 4096;
        final boolean inlineObjects = true;
        Architecture arch = new AArch64(computeFeatures(config));
        return new TargetDescription(arch, true, stackFrameAlignment, implicitNullCheckLimit, inlineObjects);
    }

    protected HotSpotConstantReflectionProvider createConstantReflection(HotSpotJVMCIRuntime runtime) {
        return new HotSpotConstantReflectionProvider(runtime);
    }

    private static RegisterConfig createRegisterConfig(AArch64HotSpotVMConfig config, TargetDescription target) {
        // ARMv8 defines r18 as being available to the platform ABI. Windows
        // and Darwin use it for such. Linux doesn't assign it and thus r18 can
        // be used as an additional register.
        boolean canUsePlatformRegister = target.linuxOs;
        return new AArch64HotSpotRegisterConfig(target, config.useCompressedOops, canUsePlatformRegister);
    }

    protected HotSpotCodeCacheProvider createCodeCache(HotSpotJVMCIRuntime runtime, TargetDescription target, RegisterConfig regConfig) {
        return new HotSpotCodeCacheProvider(runtime, target, regConfig);
    }

    protected HotSpotMetaAccessProvider createMetaAccess(HotSpotJVMCIRuntime runtime) {
        return new HotSpotMetaAccessProvider(runtime);
    }

    @Override
    public String getArchitecture() {
        return "aarch64";
    }

    @Override
    public String toString() {
        return "JVMCIBackend:" + getArchitecture();
    }

    @Override
    public JVMCIBackend createJVMCIBackend(HotSpotJVMCIRuntime runtime, JVMCIBackend host) {
        assert host == null;
        AArch64HotSpotVMConfig config = new AArch64HotSpotVMConfig(runtime.getConfigStore());
        TargetDescription target = createTarget(config);

        RegisterConfig regConfig;
        HotSpotCodeCacheProvider codeCache;
        ConstantReflectionProvider constantReflection;
        HotSpotMetaAccessProvider metaAccess;
        StackIntrospection stackIntrospection;
        try (InitTimer _ = timer("create providers")) {
            try (InitTimer _ = timer("create MetaAccess provider")) {
                metaAccess = createMetaAccess(runtime);
            }
            try (InitTimer _ = timer("create RegisterConfig")) {
                regConfig = createRegisterConfig(config, target);
            }
            try (InitTimer _ = timer("create CodeCache provider")) {
                codeCache = createCodeCache(runtime, target, regConfig);
            }
            try (InitTimer _ = timer("create ConstantReflection provider")) {
                constantReflection = createConstantReflection(runtime);
            }
            try (InitTimer _ = timer("create StackIntrospection provider")) {
                stackIntrospection = new HotSpotStackIntrospection(runtime);
            }
        }
        try (InitTimer _ = timer("instantiate backend")) {
            return createBackend(metaAccess, codeCache, constantReflection, stackIntrospection);
        }
    }

    protected JVMCIBackend createBackend(HotSpotMetaAccessProvider metaAccess, HotSpotCodeCacheProvider codeCache, ConstantReflectionProvider constantReflection,
                    StackIntrospection stackIntrospection) {
        return new JVMCIBackend(metaAccess, codeCache, constantReflection, stackIntrospection);
    }
}
