/*
 * Copyright (c) 2011, 2017, 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 jdk.vm.ci.hotspot;

import jdk.vm.ci.common.JVMCIError;
import jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.Option;
import jdk.vm.ci.meta.Constant;
import jdk.vm.ci.meta.ConstantPool;
import jdk.vm.ci.meta.DefaultProfilingInfo;
import jdk.vm.ci.meta.ExceptionHandler;
import jdk.vm.ci.meta.JavaMethod;
import jdk.vm.ci.meta.JavaType;
import jdk.vm.ci.meta.LineNumberTable;
import jdk.vm.ci.meta.Local;
import jdk.vm.ci.meta.LocalVariableTable;
import jdk.vm.ci.meta.ProfilingInfo;
import jdk.vm.ci.meta.ResolvedJavaMethod;
import jdk.vm.ci.meta.ResolvedJavaType;
import jdk.vm.ci.meta.Signature;
import jdk.vm.ci.meta.SpeculationLog;
import jdk.vm.ci.meta.TriState;

import java.lang.annotation.Annotation;
import java.lang.reflect.Executable;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import static jdk.vm.ci.hotspot.CompilerToVM.compilerToVM;
import static jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.runtime;
import static jdk.vm.ci.hotspot.HotSpotModifiers.BRIDGE;
import static jdk.vm.ci.hotspot.HotSpotModifiers.SYNTHETIC;
import static jdk.vm.ci.hotspot.HotSpotModifiers.VARARGS;
import static jdk.vm.ci.hotspot.HotSpotModifiers.jvmMethodModifiers;
import static jdk.vm.ci.hotspot.HotSpotVMConfig.config;
import static jdk.vm.ci.hotspot.UnsafeAccess.UNSAFE;

Implementation of JavaMethod for resolved HotSpot methods. /**
 * Implementation of {@link JavaMethod} for resolved HotSpot methods.
 */
final class HotSpotResolvedJavaMethodImpl extends HotSpotMethod implements HotSpotResolvedJavaMethod, MetaspaceWrapperObject {

    
Reference to metaspace Method object.
/**
     * Reference to metaspace Method object.
     */
    private final long metaspaceMethod;

    private final HotSpotResolvedObjectTypeImpl holder;
    private final HotSpotConstantPool constantPool;
    private final HotSpotSignature signature;
    private HotSpotMethodData methodData;
    private byte[] code;
    private Executable toJavaCache;

    
Only 30% of HotSpotResolvedJavaMethodImpls have their name accessed so compute it lazily and cache it. /**
     * Only 30% of {@link HotSpotResolvedJavaMethodImpl}s have their name accessed so compute it
     * lazily and cache it.
     */
    private String nameCache;

    
Gets the holder of a HotSpot metaspace method native object.
Params:
metaspaceMethod – a metaspace Method object
Returns:
the ResolvedJavaType corresponding to the holder of the metaspaceMethod/**
     * Gets the holder of a HotSpot metaspace method native object.
     *
     * @param metaspaceMethod a metaspace Method object
     * @return the {@link ResolvedJavaType} corresponding to the holder of the
     *         {@code metaspaceMethod}
     */
    private static HotSpotResolvedObjectTypeImpl getHolder(long metaspaceMethod) {
        HotSpotVMConfig config = config();
        final long metaspaceConstMethod = UNSAFE.getAddress(metaspaceMethod + config.methodConstMethodOffset);
        final long metaspaceConstantPool = UNSAFE.getAddress(metaspaceConstMethod + config.constMethodConstantsOffset);
        return compilerToVM().getResolvedJavaType(null, metaspaceConstantPool + config.constantPoolHolderOffset, false);
    }

    
Gets the JVMCI mirror from a HotSpot method. The VM is responsible for ensuring that the Method* is kept alive for the duration of this call and the HotSpotJVMCIMetaAccessContext keeps it alive after that. Called from the VM. 
Params:
metaspaceMethod – a metaspace Method object
Returns:
the ResolvedJavaMethod corresponding to metaspaceMethod/**
     * Gets the JVMCI mirror from a HotSpot method. The VM is responsible for ensuring that the
     * Method* is kept alive for the duration of this call and the
     * {@link HotSpotJVMCIMetaAccessContext} keeps it alive after that.
     *
     * Called from the VM.
     *
     * @param metaspaceMethod a metaspace Method object
     * @return the {@link ResolvedJavaMethod} corresponding to {@code metaspaceMethod}
     */
    @SuppressWarnings("unused")
    private static HotSpotResolvedJavaMethod fromMetaspace(long metaspaceMethod) {
        HotSpotResolvedObjectTypeImpl holder = getHolder(metaspaceMethod);
        return holder.createMethod(metaspaceMethod);
    }

    HotSpotResolvedJavaMethodImpl(HotSpotResolvedObjectTypeImpl holder, long metaspaceMethod) {
        this.metaspaceMethod = metaspaceMethod;
        this.holder = holder;

        HotSpotVMConfig config = config();
        final long constMethod = getConstMethod();

        /*
         * Get the constant pool from the metaspace method. Some methods (e.g. intrinsics for
         * signature-polymorphic method handle methods) have their own constant pool instead of the
         * one from their holder.
         */
        final long metaspaceConstantPool = UNSAFE.getAddress(constMethod + config.constMethodConstantsOffset);
        if (metaspaceConstantPool == holder.getConstantPool().getMetaspaceConstantPool()) {
            this.constantPool = holder.getConstantPool();
        } else {
            this.constantPool = compilerToVM().getConstantPool(this);
        }

        final int signatureIndex = UNSAFE.getChar(constMethod + config.constMethodSignatureIndexOffset);
        this.signature = (HotSpotSignature) constantPool.lookupSignature(signatureIndex);
    }

    
Returns a pointer to this method's constant method data structure ( Method::_constMethod). This pointer isn't wrapped since it should be safe to use it within the context of this HotSpotResolvedJavaMethodImpl since the Method* and ConstMethod* are kept alive as a pair. 
Returns:
pointer to this method's ConstMethod/**
     * Returns a pointer to this method's constant method data structure (
     * {@code Method::_constMethod}). This pointer isn't wrapped since it should be safe to use it
     * within the context of this HotSpotResolvedJavaMethodImpl since the Method* and ConstMethod*
     * are kept alive as a pair.
     *
     * @return pointer to this method's ConstMethod
     */
    private long getConstMethod() {
        assert metaspaceMethod != 0;
        return UNSAFE.getAddress(metaspaceMethod + config().methodConstMethodOffset);
    }

    @Override
    public String getName() {
        if (nameCache == null) {
            final int nameIndex = UNSAFE.getChar(getConstMethod() + config().constMethodNameIndexOffset);
            nameCache = constantPool.lookupUtf8(nameIndex);
        }
        return nameCache;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj instanceof HotSpotResolvedJavaMethodImpl) {
            HotSpotResolvedJavaMethodImpl that = (HotSpotResolvedJavaMethodImpl) obj;
            return that.metaspaceMethod == metaspaceMethod;
        }
        return false;
    }

    @Override
    public int hashCode() {
        return (int) metaspaceMethod;
    }

    
Returns this method's flags (Method::_flags). 
Returns:
flags of this method/**
     * Returns this method's flags ({@code Method::_flags}).
     *
     * @return flags of this method
     */
    private int getFlags() {
        return UNSAFE.getShort(metaspaceMethod + config().methodFlagsOffset);
    }

    
Returns this method's constant method flags (ConstMethod::_flags). 
Returns:
flags of this method's ConstMethod/**
     * Returns this method's constant method flags ({@code ConstMethod::_flags}).
     *
     * @return flags of this method's ConstMethod
     */
    private int getConstMethodFlags() {
        return UNSAFE.getChar(getConstMethod() + config().constMethodFlagsOffset);
    }

    @Override
    public HotSpotResolvedObjectTypeImpl getDeclaringClass() {
        return holder;
    }

    
Gets the address of the C++ Method object for this method.
/**
     * Gets the address of the C++ Method object for this method.
     */
    public Constant getMetaspaceMethodConstant() {
        return HotSpotMetaspaceConstantImpl.forMetaspaceObject(this, false);
    }

    @Override
    public long getMetaspacePointer() {
        return metaspaceMethod;
    }

    @Override
    public Constant getEncoding() {
        return getMetaspaceMethodConstant();
    }

    
Gets the complete set of modifiers for this method which includes the JVM specification
modifiers as well as the HotSpot internal modifiers.
/**
     * Gets the complete set of modifiers for this method which includes the JVM specification
     * modifiers as well as the HotSpot internal modifiers.
     */
    public int getAllModifiers() {
        return UNSAFE.getInt(metaspaceMethod + config().methodAccessFlagsOffset);
    }

    @Override
    public int getModifiers() {
        return getAllModifiers() & jvmMethodModifiers();
    }

    @Override
    public boolean canBeStaticallyBound() {
        return (isFinal() || isPrivate() || isStatic() || holder.isLeaf()) && isConcrete();
    }

    @Override
    public byte[] getCode() {
        if (getCodeSize() == 0) {
            return null;
        }
        if (code == null && holder.isLinked()) {
            code = compilerToVM().getBytecode(this);
            assert code.length == getCodeSize() : "expected: " + getCodeSize() + ", actual: " + code.length;
        }
        return code;
    }

    @Override
    public int getCodeSize() {
        return UNSAFE.getChar(getConstMethod() + config().constMethodCodeSizeOffset);
    }

    @Override
    public ExceptionHandler[] getExceptionHandlers() {
        final boolean hasExceptionTable = (getConstMethodFlags() & config().constMethodHasExceptionTable) != 0;
        if (!hasExceptionTable) {
            return new ExceptionHandler[0];
        }

        HotSpotVMConfig config = config();
        final int exceptionTableLength = compilerToVM().getExceptionTableLength(this);
        ExceptionHandler[] handlers = new ExceptionHandler[exceptionTableLength];
        long exceptionTableElement = compilerToVM().getExceptionTableStart(this);

        for (int i = 0; i < exceptionTableLength; i++) {
            final int startPc = UNSAFE.getChar(exceptionTableElement + config.exceptionTableElementStartPcOffset);
            final int endPc = UNSAFE.getChar(exceptionTableElement + config.exceptionTableElementEndPcOffset);
            final int handlerPc = UNSAFE.getChar(exceptionTableElement + config.exceptionTableElementHandlerPcOffset);
            int catchTypeIndex = UNSAFE.getChar(exceptionTableElement + config.exceptionTableElementCatchTypeIndexOffset);

            JavaType catchType;
            if (catchTypeIndex == 0) {
                catchType = null;
            } else {
                final int opcode = -1;  // opcode is not used
                catchType = constantPool.lookupType(catchTypeIndex, opcode);

                // Check for Throwable which catches everything.
                if (catchType instanceof HotSpotResolvedObjectTypeImpl) {
                    HotSpotResolvedObjectTypeImpl resolvedType = (HotSpotResolvedObjectTypeImpl) catchType;
                    if (resolvedType.mirror() == Throwable.class) {
                        catchTypeIndex = 0;
                        catchType = null;
                    }
                }
            }
            handlers[i] = new ExceptionHandler(startPc, endPc, handlerPc, catchTypeIndex, catchType);

            // Go to the next ExceptionTableElement
            exceptionTableElement += config.exceptionTableElementSize;
        }

        return handlers;
    }

    
Returns true if this method has a CallerSensitive annotation. 
Returns:
true if CallerSensitive annotation present, false otherwise/**
     * Returns true if this method has a {@code CallerSensitive} annotation.
     *
     * @return true if CallerSensitive annotation present, false otherwise
     */
    @Override
    public boolean isCallerSensitive() {
        return (getFlags() & config().methodFlagsCallerSensitive) != 0;
    }

    
Returns true if this method has a ForceInline annotation. 
Returns:
true if ForceInline annotation present, false otherwise/**
     * Returns true if this method has a {@code ForceInline} annotation.
     *
     * @return true if ForceInline annotation present, false otherwise
     */
    @Override
    public boolean isForceInline() {
        return (getFlags() & config().methodFlagsForceInline) != 0;
    }

    
Returns true if this method has a ReservedStackAccess annotation. 
Returns:
true if ReservedStackAccess annotation present, false otherwise/**
     * Returns true if this method has a {@code ReservedStackAccess} annotation.
     *
     * @return true if ReservedStackAccess annotation present, false otherwise
     */
    @Override
    public boolean hasReservedStackAccess() {
        return (getFlags() & config().methodFlagsReservedStackAccess) != 0;
    }

    
Sets flags on method indicating that it should never be inlined or compiled by the VM. /**
     * Sets flags on {@code method} indicating that it should never be inlined or compiled by the VM.
     */
    @Override
    public void setNotInlinableOrCompilable() {
        compilerToVM().setNotInlinableOrCompilable(this);
    }

    
Returns true if this method is one of the special methods that is ignored by security stack
walks.
Returns:
true if special method ignored by security stack walks, false otherwise/**
     * Returns true if this method is one of the special methods that is ignored by security stack
     * walks.
     *
     * @return true if special method ignored by security stack walks, false otherwise
     */
    @Override
    public boolean ignoredBySecurityStackWalk() {
        return compilerToVM().methodIsIgnoredBySecurityStackWalk(this);
    }

    @Override
    public boolean isClassInitializer() {
        if (isStatic()) {
            final int nameIndex = UNSAFE.getChar(getConstMethod() + config().constMethodNameIndexOffset);
            long nameSymbol = constantPool.getEntryAt(nameIndex);
            long clinitSymbol = config().symbolClinit;
            return nameSymbol == clinitSymbol;
        }
        return false;
    }

    @Override
    public boolean isConstructor() {
        if (!isStatic()) {
            final int nameIndex = UNSAFE.getChar(getConstMethod() + config().constMethodNameIndexOffset);
            long nameSymbol = constantPool.getEntryAt(nameIndex);
            long initSymbol = config().symbolInit;
            return nameSymbol == initSymbol;
        }
        return false;
    }

    @Override
    public int getMaxLocals() {
        if (isAbstract() || isNative()) {
            return 0;
        }
        HotSpotVMConfig config = config();
        return UNSAFE.getChar(getConstMethod() + config.methodMaxLocalsOffset);
    }

    @Override
    public int getMaxStackSize() {
        if (isAbstract() || isNative()) {
            return 0;
        }
        HotSpotVMConfig config = config();
        return config.extraStackEntries + UNSAFE.getChar(getConstMethod() + config.constMethodMaxStackOffset);
    }

    @Override
    public StackTraceElement asStackTraceElement(int bci) {
        if (bci < 0 || bci >= getCodeSize()) {
            // HotSpot code can only construct stack trace elements for valid bcis
            StackTraceElement ste = compilerToVM().getStackTraceElement(this, 0);
            return new StackTraceElement(ste.getClassName(), ste.getMethodName(), ste.getFileName(), -1);
        }
        return compilerToVM().getStackTraceElement(this, bci);
    }

    @Override
    public ResolvedJavaMethod uniqueConcreteMethod(HotSpotResolvedObjectType receiver) {
        if (receiver.isInterface()) {
            // Cannot trust interfaces. Because of:
            // interface I { void foo(); }
            // class A { public void foo() {} }
            // class B extends A implements I { }
            // class C extends B { public void foo() { } }
            // class D extends B { }
            // Would lead to identify C.foo() as the unique concrete method for I.foo() without
            // seeing A.foo().
            return null;
        }
        if (this.isDefault()) {
            // CHA for default methods doesn't work and may crash the VM
            return null;
        }
        return compilerToVM().findUniqueConcreteMethod(((HotSpotResolvedObjectTypeImpl) receiver), this);
    }

    @Override
    public HotSpotSignature getSignature() {
        return signature;
    }

    
Gets the value of Method::_code. 
Returns:
the value of Method::_code/**
     * Gets the value of {@code Method::_code}.
     *
     * @return the value of {@code Method::_code}
     */
    private long getCompiledCode() {
        HotSpotVMConfig config = config();
        return UNSAFE.getAddress(metaspaceMethod + config.methodCodeOffset);
    }

    
Returns whether this method has compiled code.
Returns:
true if this method has compiled code, false otherwise/**
     * Returns whether this method has compiled code.
     *
     * @return true if this method has compiled code, false otherwise
     */
    @Override
    public boolean hasCompiledCode() {
        return getCompiledCode() != 0L;
    }

    
Params:
level – 
Returns:
true if the currently installed code was generated at level./**
     * @param level
     * @return true if the currently installed code was generated at {@code level}.
     */
    @Override
    public boolean hasCompiledCodeAtLevel(int level) {
        long compiledCode = getCompiledCode();
        if (compiledCode != 0) {
            return UNSAFE.getInt(compiledCode + config().nmethodCompLevelOffset) == level;
        }
        return false;
    }

    @Override
    public ProfilingInfo getProfilingInfo(boolean includeNormal, boolean includeOSR) {
        ProfilingInfo info;

        if (Option.UseProfilingInformation.getBoolean() && methodData == null) {
            long metaspaceMethodData = UNSAFE.getAddress(metaspaceMethod + config().methodDataOffset);
            if (metaspaceMethodData != 0) {
                methodData = new HotSpotMethodData(metaspaceMethodData, this);
                String methodDataFilter = Option.TraceMethodDataFilter.getString();
                if (methodDataFilter != null && this.format("%H.%n").contains(methodDataFilter)) {
                    System.out.println(methodData.toString());
                }
            }
        }

        if (methodData == null || (!methodData.hasNormalData() && !methodData.hasExtraData())) {
            // Be optimistic and return false for exceptionSeen. A methodDataOop is allocated in
            // case of a deoptimization.
            info = DefaultProfilingInfo.get(TriState.FALSE);
        } else {
            info = new HotSpotProfilingInfo(methodData, this, includeNormal, includeOSR);
        }
        return info;
    }

    @Override
    public void reprofile() {
        compilerToVM().reprofile(this);
    }

    @Override
    public ConstantPool getConstantPool() {
        return constantPool;
    }

    @Override
    public Parameter[] getParameters() {
        Executable javaMethod = toJava();
        if (javaMethod == null) {
            return null;
        }

        java.lang.reflect.Parameter[] javaParameters = javaMethod.getParameters();
        Parameter[] res = new Parameter[javaParameters.length];
        for (int i = 0; i < res.length; i++) {
            java.lang.reflect.Parameter src = javaParameters[i];
            String paramName = src.isNamePresent() ? src.getName() : null;
            res[i] = new Parameter(paramName, src.getModifiers(), this, i);
        }
        return res;
    }

    @Override
    public Annotation[][] getParameterAnnotations() {
        Executable javaMethod = toJava();
        return javaMethod == null ? new Annotation[signature.getParameterCount(false)][0] : javaMethod.getParameterAnnotations();
    }

    @Override
    public Annotation[] getAnnotations() {
        Executable javaMethod = toJava();
        if (javaMethod != null) {
            return javaMethod.getAnnotations();
        }
        return new Annotation[0];
    }

    @Override
    public Annotation[] getDeclaredAnnotations() {
        Executable javaMethod = toJava();
        if (javaMethod != null) {
            return javaMethod.getDeclaredAnnotations();
        }
        return new Annotation[0];
    }

    @Override
    public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
        Executable javaMethod = toJava();
        return javaMethod == null ? null : javaMethod.getAnnotation(annotationClass);
    }

    @Override
    public boolean isBridge() {
        return (BRIDGE & getModifiers()) != 0;
    }

    @Override
    public boolean isSynthetic() {
        return (SYNTHETIC & getModifiers()) != 0;
    }

    @Override
    public boolean isVarArgs() {
        return (VARARGS & getModifiers()) != 0;
    }

    @Override
    public boolean isDefault() {
        // Copied from java.lang.Method.isDefault()
        int mask = Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC;
        return ((getModifiers() & mask) == Modifier.PUBLIC) && getDeclaringClass().isInterface();
    }

    @Override
    public Type[] getGenericParameterTypes() {
        Executable javaMethod = toJava();
        return javaMethod == null ? null : javaMethod.getGenericParameterTypes();
    }

    public Class<?>[] signatureToTypes() {
        Signature sig = getSignature();
        int count = sig.getParameterCount(false);
        Class<?>[] result = new Class<?>[count];
        for (int i = 0; i < result.length; ++i) {
            JavaType parameterType = sig.getParameterType(i, holder);
            HotSpotResolvedJavaType resolvedParameterType = (HotSpotResolvedJavaType) parameterType.resolve(holder);
            result[i] = resolvedParameterType.mirror();
        }
        return result;
    }

    private static Method searchMethods(Method[] methods, String name, Class<?> returnType, Class<?>[] parameterTypes) {
        for (Method m : methods) {
            if (m.getName().equals(name) && returnType.equals(m.getReturnType()) && Arrays.equals(m.getParameterTypes(), parameterTypes)) {
                return m;
            }
        }
        return null;
    }

    private Executable toJava() {
        if (toJavaCache != null) {
            return toJavaCache;
        }
        try {
            Class<?>[] parameterTypes = signatureToTypes();
            Class<?> returnType = ((HotSpotResolvedJavaType) getSignature().getReturnType(holder).resolve(holder)).mirror();

            Executable result;
            if (isConstructor()) {
                result = holder.mirror().getDeclaredConstructor(parameterTypes);
            } else {
                // Do not use Method.getDeclaredMethod() as it can return a bridge method
                // when this.isBridge() is false and vice versa.
                result = searchMethods(holder.mirror().getDeclaredMethods(), getName(), returnType, parameterTypes);
            }
            toJavaCache = result;
            return result;
        } catch (NoSuchMethodException | NoClassDefFoundError e) {
            return null;
        }
    }

    @Override
    public boolean canBeInlined() {
        if (hasNeverInlineDirective()) {
            return false;
        }
        return compilerToVM().isCompilable(this);
    }

    @Override
    public boolean hasNeverInlineDirective() {
        return compilerToVM().hasNeverInlineDirective(this);
    }

    @Override
    public boolean shouldBeInlined() {
        if (isForceInline()) {
            return true;
        }
        return compilerToVM().shouldInlineMethod(this);
    }

    @Override
    public LineNumberTable getLineNumberTable() {
        final boolean hasLineNumberTable = (getConstMethodFlags() & config().constMethodHasLineNumberTable) != 0;
        if (!hasLineNumberTable) {
            return null;
        }

        long[] values = compilerToVM().getLineNumberTable(this);
        if (values == null || values.length == 0) {
            // Empty table so treat is as non-existent
            return null;
        }
        assert values.length % 2 == 0;
        int[] bci = new int[values.length / 2];
        int[] line = new int[values.length / 2];

        for (int i = 0; i < values.length / 2; i++) {
            bci[i] = (int) values[i * 2];
            line[i] = (int) values[i * 2 + 1];
        }

        return new LineNumberTable(line, bci);
    }

    @Override
    public LocalVariableTable getLocalVariableTable() {
        final boolean hasLocalVariableTable = (getConstMethodFlags() & config().constMethodHasLocalVariableTable) != 0;
        if (!hasLocalVariableTable) {
            return null;
        }

        HotSpotVMConfig config = config();
        long localVariableTableElement = compilerToVM().getLocalVariableTableStart(this);
        final int localVariableTableLength = compilerToVM().getLocalVariableTableLength(this);
        Local[] locals = new Local[localVariableTableLength];

        for (int i = 0; i < localVariableTableLength; i++) {
            final int startBci = UNSAFE.getChar(localVariableTableElement + config.localVariableTableElementStartBciOffset);
            final int endBci = startBci + UNSAFE.getChar(localVariableTableElement + config.localVariableTableElementLengthOffset);
            final int nameCpIndex = UNSAFE.getChar(localVariableTableElement + config.localVariableTableElementNameCpIndexOffset);
            final int typeCpIndex = UNSAFE.getChar(localVariableTableElement + config.localVariableTableElementDescriptorCpIndexOffset);
            final int slot = UNSAFE.getChar(localVariableTableElement + config.localVariableTableElementSlotOffset);

            String localName = getConstantPool().lookupUtf8(nameCpIndex);
            String localType = getConstantPool().lookupUtf8(typeCpIndex);

            locals[i] = new Local(localName, runtime().lookupType(localType, holder, false), startBci, endBci, slot);

            // Go to the next LocalVariableTableElement
            localVariableTableElement += config.localVariableTableElementSize;
        }

        return new LocalVariableTable(locals);
    }

    
Returns the offset of this method into the v-table. The method must have a v-table entry as indicated by isInVirtualMethodTable(ResolvedJavaType), otherwise an exception is thrown. 
Returns:
the offset of this method into the v-table/**
     * Returns the offset of this method into the v-table. The method must have a v-table entry as
     * indicated by {@link #isInVirtualMethodTable(ResolvedJavaType)}, otherwise an exception is
     * thrown.
     *
     * @return the offset of this method into the v-table
     */
    @Override
    public int vtableEntryOffset(ResolvedJavaType resolved) {
        if (!isInVirtualMethodTable(resolved)) {
            throw new JVMCIError("%s does not have a vtable entry in type %s", this, resolved);
        }
        HotSpotVMConfig config = config();
        final int vtableIndex = getVtableIndex((HotSpotResolvedObjectTypeImpl) resolved);
        return config.klassVtableStartOffset + vtableIndex * config.vtableEntrySize + config.vtableEntryMethodOffset;
    }

    @Override
    public boolean isInVirtualMethodTable(ResolvedJavaType resolved) {
        if (resolved instanceof HotSpotResolvedObjectTypeImpl) {
            HotSpotResolvedObjectTypeImpl hotspotResolved = (HotSpotResolvedObjectTypeImpl) resolved;
            int vtableIndex = getVtableIndex(hotspotResolved);
            return vtableIndex >= 0 && vtableIndex < hotspotResolved.getVtableLength();
        }
        return false;
    }

    private int getVtableIndex(HotSpotResolvedObjectTypeImpl resolved) {
        if (!holder.isLinked()) {
            return config().invalidVtableIndex;
        }
        if (holder.isInterface()) {
            if (resolved.isInterface()) {
                return config().invalidVtableIndex;
            }
            return getVtableIndexForInterfaceMethod(resolved);
        }
        return getVtableIndex();
    }

    
Returns this method's virtual table index.
Returns:
virtual table index/**
     * Returns this method's virtual table index.
     *
     * @return virtual table index
     */
    private int getVtableIndex() {
        assert !holder.isInterface();
        HotSpotVMConfig config = config();
        int result = UNSAFE.getInt(metaspaceMethod + config.methodVtableIndexOffset);
        assert result >= config.nonvirtualVtableIndex : "must be linked";
        return result;
    }

    private int getVtableIndexForInterfaceMethod(ResolvedJavaType resolved) {
        HotSpotResolvedObjectTypeImpl hotspotType = (HotSpotResolvedObjectTypeImpl) resolved;
        return compilerToVM().getVtableIndexForInterfaceMethod(hotspotType, this);
    }

    
The SpeculationLog for methods compiled by JVMCI hang off this per-declaring-type ClassValue. The raw Method* value is safe to use as a key in the map as a) it is never moves and b) we never read from it. 
 One implication is that we will preserve SpeculationLogs for methods that have been redefined via class redefinition. It's tempting to periodically flush such logs but we cannot read the JVM_ACC_IS_OBSOLETE bit (or anything else) via the raw pointer as obsoleted methods are subject to clean up and deletion (see InstanceKlass::purge_previous_versions_internal). /**
     * The {@link SpeculationLog} for methods compiled by JVMCI hang off this per-declaring-type
     * {@link ClassValue}. The raw Method* value is safe to use as a key in the map as a) it is
     * never moves and b) we never read from it.
     * <p>
     * One implication is that we will preserve {@link SpeculationLog}s for methods that have been
     * redefined via class redefinition. It's tempting to periodically flush such logs but we cannot
     * read the JVM_ACC_IS_OBSOLETE bit (or anything else) via the raw pointer as obsoleted methods
     * are subject to clean up and deletion (see InstanceKlass::purge_previous_versions_internal).
     */
    private static final ClassValue<Map<Long, SpeculationLog>> SpeculationLogs = new ClassValue<Map<Long, SpeculationLog>>() {
        @Override
        protected Map<Long, SpeculationLog> computeValue(java.lang.Class<?> type) {
            return new HashMap<>(4);
        }
    };

    @Override
    public SpeculationLog getSpeculationLog() {
        Map<Long, SpeculationLog> map = SpeculationLogs.get(holder.mirror());
        synchronized (map) {
            SpeculationLog log = map.get(this.metaspaceMethod);
            if (log == null) {
                log = new HotSpotSpeculationLog();
                map.put(metaspaceMethod, log);
            }
            return log;
        }
    }

    @Override
    public int intrinsicId() {
        HotSpotVMConfig config = config();
        return UNSAFE.getChar(metaspaceMethod + config.methodIntrinsicIdOffset);
    }

    @Override
    public boolean isIntrinsicCandidate() {
        return (getFlags() & config().methodFlagsIntrinsicCandidate) != 0;
    }

    
Allocates a compile id for this method by asking the VM for one.
Params:
entryBCI – entry bci
Returns:
compile id/**
     * Allocates a compile id for this method by asking the VM for one.
     *
     * @param entryBCI entry bci
     * @return compile id
     */
    @Override
    public int allocateCompileId(int entryBCI) {
        return compilerToVM().allocateCompileId(this, entryBCI);
    }

    @Override
    public boolean hasCodeAtLevel(int entryBCI, int level) {
        if (entryBCI == config().invocationEntryBci) {
            return hasCompiledCodeAtLevel(level);
        }
        return compilerToVM().hasCompiledCodeForOSR(this, entryBCI, level);
    }

    public int methodIdnum() {
        return UNSAFE.getChar(getConstMethod() + config().constMethodMethodIdnumOffset);
    }
}