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	/*
	* Copyright (c) 2008, 2018, 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. 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
	* 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 java.lang.invoke;

	import jdk.internal.misc.Unsafe;
	import jdk.internal.vm.annotation.ForceInline;
	import jdk.internal.vm.annotation.Stable;
	import sun.invoke.util.ValueConversions;
	import sun.invoke.util.VerifyAccess;
	import sun.invoke.util.VerifyType;
	import sun.invoke.util.Wrapper;

	import java.lang.ref.WeakReference;
	import java.util.Arrays;
	import java.util.Objects;

	import static java.lang.invoke.LambdaForm.*;
	import static java.lang.invoke.LambdaForm.Kind.*;
	import static java.lang.invoke.MethodHandleNatives.Constants.*;
	import static java.lang.invoke.MethodHandleStatics.UNSAFE;
	import static java.lang.invoke.MethodHandleStatics.newInternalError;
	import static java.lang.invoke.MethodTypeForm.*;

	/**
	* The flavor of method handle which implements a constant reference
	* to a class member.
	* @author jrose
	*/
	class DirectMethodHandle extends MethodHandle {
	final MemberName member;

	// Constructors and factory methods in this class must be package scoped or private.
	private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member) {
	super(mtype, form);
	if (!member.isResolved()) throw new InternalError();

	if (member.getDeclaringClass().isInterface() &&
	member.getReferenceKind() == REF_invokeInterface &&
	member.isMethod() && !member.isAbstract()) {
	// Check for corner case: invokeinterface of Object method
	MemberName m = new MemberName(Object.class, member.getName(), member.getMethodType(), member.getReferenceKind());
	m = MemberName.getFactory().resolveOrNull(m.getReferenceKind(), m, null);
	if (m != null && m.isPublic()) {
	assert(member.getReferenceKind() == m.getReferenceKind()); // else this.form is wrong
	member = m;
	}
	}

	this.member = member;
	}

	// Factory methods:
	static DirectMethodHandle make(byte refKind, Class<?> refc, MemberName member, Class<?> callerClass) {
	MethodType mtype = member.getMethodOrFieldType();
	if (!member.isStatic()) {
	if (!member.getDeclaringClass().isAssignableFrom(refc) \|\| member.isConstructor())
	throw new InternalError(member.toString());
	mtype = mtype.insertParameterTypes(0, refc);
	}
	if (!member.isField()) {
	// refKind reflects the original type of lookup via findSpecial or
	// findVirtual etc.
	switch (refKind) {
	case REF_invokeSpecial: {
	member = member.asSpecial();
	// if caller is an interface we need to adapt to get the
	// receiver check inserted
	if (callerClass == null) {
	throw new InternalError("callerClass must not be null for REF_invokeSpecial");
	}
	LambdaForm lform = preparedLambdaForm(member, callerClass.isInterface());
	return new Special(mtype, lform, member, callerClass);
	}
	case REF_invokeInterface: {
	// for interfaces we always need the receiver typecheck,
	// so we always pass 'true' to ensure we adapt if needed
	// to include the REF_invokeSpecial case
	LambdaForm lform = preparedLambdaForm(member, true);
	return new Interface(mtype, lform, member, refc);
	}
	default: {
	LambdaForm lform = preparedLambdaForm(member);
	return new DirectMethodHandle(mtype, lform, member);
	}
	}
	} else {
	LambdaForm lform = preparedFieldLambdaForm(member);
	if (member.isStatic()) {
	long offset = MethodHandleNatives.staticFieldOffset(member);
	Object base = MethodHandleNatives.staticFieldBase(member);
	return new StaticAccessor(mtype, lform, member, base, offset);
	} else {
	long offset = MethodHandleNatives.objectFieldOffset(member);
	assert(offset == (int)offset);
	return new Accessor(mtype, lform, member, (int)offset);
	}
	}
	}
	static DirectMethodHandle make(Class<?> refc, MemberName member) {
	byte refKind = member.getReferenceKind();
	if (refKind == REF_invokeSpecial)
	refKind = REF_invokeVirtual;
	return make(refKind, refc, member, null /* no callerClass context */);
	}
	static DirectMethodHandle make(MemberName member) {
	if (member.isConstructor())
	return makeAllocator(member);
	return make(member.getDeclaringClass(), member);
	}
	private static DirectMethodHandle makeAllocator(MemberName ctor) {
	assert(ctor.isConstructor() && ctor.getName().equals("<init>"));
	Class<?> instanceClass = ctor.getDeclaringClass();
	ctor = ctor.asConstructor();
	assert(ctor.isConstructor() && ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
	MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
	LambdaForm lform = preparedLambdaForm(ctor);
	MemberName init = ctor.asSpecial();
	assert(init.getMethodType().returnType() == void.class);
	return new Constructor(mtype, lform, ctor, init, instanceClass);
	}

	@Override
	BoundMethodHandle rebind() {
	return BoundMethodHandle.makeReinvoker(this);
	}

	@Override
	MethodHandle copyWith(MethodType mt, LambdaForm lf) {
	assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
	return new DirectMethodHandle(mt, lf, member);
	}

	@Override
	String internalProperties() {
	return "\n& DMH.MN="+internalMemberName();
	}

	//// Implementation methods.
	@Override
	@ForceInline
	MemberName internalMemberName() {
	return member;
	}

	private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();

	/**
	* Create a LF which can invoke the given method.
	* Cache and share this structure among all methods with
	* the same basicType and refKind.
	*/
	private static LambdaForm preparedLambdaForm(MemberName m, boolean adaptToSpecialIfc) {
	assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead
	MethodType mtype = m.getInvocationType().basicType();
	assert(!m.isMethodHandleInvoke()) : m;
	int which;
	// MemberName.getReferenceKind represents the JVM optimized form of the call
	// as distinct from the "kind" passed to DMH.make which represents the original
	// bytecode-equivalent request. Specifically private/final methods that use a direct
	// call have getReferenceKind adapted to REF_invokeSpecial, even though the actual
	// invocation mode may be invokevirtual or invokeinterface.
	switch (m.getReferenceKind()) {
	case REF_invokeVirtual: which = LF_INVVIRTUAL; break;
	case REF_invokeStatic: which = LF_INVSTATIC; break;
	case REF_invokeSpecial: which = LF_INVSPECIAL; break;
	case REF_invokeInterface: which = LF_INVINTERFACE; break;
	case REF_newInvokeSpecial: which = LF_NEWINVSPECIAL; break;
	default: throw new InternalError(m.toString());
	}
	if (which == LF_INVSTATIC && shouldBeInitialized(m)) {
	// precompute the barrier-free version:
	preparedLambdaForm(mtype, which);
	which = LF_INVSTATIC_INIT;
	}
	if (which == LF_INVSPECIAL && adaptToSpecialIfc) {
	which = LF_INVSPECIAL_IFC;
	}
	LambdaForm lform = preparedLambdaForm(mtype, which);
	maybeCompile(lform, m);
	assert(lform.methodType().dropParameterTypes(0, 1)
	.equals(m.getInvocationType().basicType()))
	: Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
	return lform;
	}

	private static LambdaForm preparedLambdaForm(MemberName m) {
	return preparedLambdaForm(m, false);
	}

	private static LambdaForm preparedLambdaForm(MethodType mtype, int which) {
	LambdaForm lform = mtype.form().cachedLambdaForm(which);
	if (lform != null) return lform;
	lform = makePreparedLambdaForm(mtype, which);
	return mtype.form().setCachedLambdaForm(which, lform);
	}

	static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) {
	boolean needsInit = (which == LF_INVSTATIC_INIT);
	boolean doesAlloc = (which == LF_NEWINVSPECIAL);
	boolean needsReceiverCheck = (which == LF_INVINTERFACE \|\|
	which == LF_INVSPECIAL_IFC);

	String linkerName;
	LambdaForm.Kind kind;
	switch (which) {
	case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break;
	case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break;
	case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break;
	case LF_INVSPECIAL_IFC:linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL_IFC; break;
	case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break;
	case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break;
	case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break;
	default: throw new InternalError("which="+which);
	}

	MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class);
	if (doesAlloc)
	mtypeWithArg = mtypeWithArg
	.insertParameterTypes(0, Object.class) // insert newly allocated obj
	.changeReturnType(void.class); // <init> returns void
	MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
	try {
	linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, NoSuchMethodException.class);
	} catch (ReflectiveOperationException ex) {
	throw newInternalError(ex);
	}
	final int DMH_THIS = 0;
	final int ARG_BASE = 1;
	final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
	int nameCursor = ARG_LIMIT;
	final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
	final int GET_MEMBER = nameCursor++;
	final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1);
	final int LINKER_CALL = nameCursor++;
	Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
	assert(names.length == nameCursor);
	if (doesAlloc) {
	// names = { argx,y,z,... new C, init method }
	names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]);
	names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]);
	} else if (needsInit) {
	names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]);
	} else {
	names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]);
	}
	assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
	Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
	if (needsReceiverCheck) {
	names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]);
	outArgs[0] = names[CHECK_RECEIVER];
	}
	assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
	int result = LAST_RESULT;
	if (doesAlloc) {
	assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
	System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
	outArgs[0] = names[NEW_OBJ];
	result = NEW_OBJ;
	}
	names[LINKER_CALL] = new Name(linker, outArgs);
	LambdaForm lform = new LambdaForm(ARG_LIMIT, names, result, kind);

	// This is a tricky bit of code. Don't send it through the LF interpreter.
	lform.compileToBytecode();
	return lform;
	}

	/* assert */ static Object findDirectMethodHandle(Name name) {
	if (name.function.equals(getFunction(NF_internalMemberName)) \|\|
	name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) \|\|
	name.function.equals(getFunction(NF_constructorMethod))) {
	assert(name.arguments.length == 1);
	return name.arguments[0];
	}
	return null;
	}

	private static void maybeCompile(LambdaForm lform, MemberName m) {
	if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
	// Help along bootstrapping...
	lform.compileToBytecode();
	}

	/** Static wrapper for DirectMethodHandle.internalMemberName. */
	@ForceInline
	/non-public/ static Object internalMemberName(Object mh) {
	return ((DirectMethodHandle)mh).member;
	}

	/** Static wrapper for DirectMethodHandle.internalMemberName.
	* This one also forces initialization.
	*/
	/non-public/ static Object internalMemberNameEnsureInit(Object mh) {
	DirectMethodHandle dmh = (DirectMethodHandle)mh;
	dmh.ensureInitialized();
	return dmh.member;
	}

	/non-public/ static
	boolean shouldBeInitialized(MemberName member) {
	switch (member.getReferenceKind()) {
	case REF_invokeStatic:
	case REF_getStatic:
	case REF_putStatic:
	case REF_newInvokeSpecial:
	break;
	default:
	// No need to initialize the class on this kind of member.
	return false;
	}
	Class<?> cls = member.getDeclaringClass();
	if (cls == ValueConversions.class \|\|
	cls == MethodHandleImpl.class \|\|
	cls == Invokers.class) {
	// These guys have lots of <clinit> DMH creation but we know
	// the MHs will not be used until the system is booted.
	return false;
	}
	if (VerifyAccess.isSamePackage(MethodHandle.class, cls) \|\|
	VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
	// It is a system class. It is probably in the process of
	// being initialized, but we will help it along just to be safe.
	if (UNSAFE.shouldBeInitialized(cls)) {
	UNSAFE.ensureClassInitialized(cls);
	}
	return false;
	}
	return UNSAFE.shouldBeInitialized(cls);
	}

	private static class EnsureInitialized extends ClassValue<WeakReference<Thread>> {
	@Override
	protected WeakReference<Thread> computeValue(Class<?> type) {
	UNSAFE.ensureClassInitialized(type);
	if (UNSAFE.shouldBeInitialized(type))
	// If the previous call didn't block, this can happen.
	// We are executing inside <clinit>.
	return new WeakReference<>(Thread.currentThread());
	return null;
	}
	static final EnsureInitialized INSTANCE = new EnsureInitialized();
	}

	private void ensureInitialized() {
	if (checkInitialized(member)) {
	// The coast is clear. Delete the <clinit> barrier.
	if (member.isField())
	updateForm(preparedFieldLambdaForm(member));
	else
	updateForm(preparedLambdaForm(member));
	}
	}
	private static boolean checkInitialized(MemberName member) {
	Class<?> defc = member.getDeclaringClass();
	WeakReference<Thread> ref = EnsureInitialized.INSTANCE.get(defc);
	if (ref == null) {
	return true; // the final state
	}
	Thread clinitThread = ref.get();
	// Somebody may still be running defc.<clinit>.
	if (clinitThread == Thread.currentThread()) {
	// If anybody is running defc.<clinit>, it is this thread.
	if (UNSAFE.shouldBeInitialized(defc))
	// Yes, we are running it; keep the barrier for now.
	return false;
	} else {
	// We are in a random thread. Block.
	UNSAFE.ensureClassInitialized(defc);
	}
	assert(!UNSAFE.shouldBeInitialized(defc));
	// put it into the final state
	EnsureInitialized.INSTANCE.remove(defc);
	return true;
	}

	/non-public/ static void ensureInitialized(Object mh) {
	((DirectMethodHandle)mh).ensureInitialized();
	}

	/** This subclass represents invokespecial instructions. */
	static class Special extends DirectMethodHandle {
	private final Class<?> caller;
	private Special(MethodType mtype, LambdaForm form, MemberName member, Class<?> caller) {
	super(mtype, form, member);
	this.caller = caller;
	}
	@Override
	boolean isInvokeSpecial() {
	return true;
	}
	@Override
	MethodHandle copyWith(MethodType mt, LambdaForm lf) {
	return new Special(mt, lf, member, caller);
	}
	Object checkReceiver(Object recv) {
	if (!caller.isInstance(recv)) {
	String msg = String.format("Receiver class %s is not a subclass of caller class %s",
	recv.getClass().getName(), caller.getName());
	throw new IncompatibleClassChangeError(msg);
	}
	return recv;
	}
	}

	/** This subclass represents invokeinterface instructions. */
	static class Interface extends DirectMethodHandle {
	private final Class<?> refc;
	private Interface(MethodType mtype, LambdaForm form, MemberName member, Class<?> refc) {
	super(mtype, form, member);
	assert refc.isInterface() : refc;
	this.refc = refc;
	}
	@Override
	MethodHandle copyWith(MethodType mt, LambdaForm lf) {
	return new Interface(mt, lf, member, refc);
	}
	@Override
	Object checkReceiver(Object recv) {
	if (!refc.isInstance(recv)) {
	String msg = String.format("Receiver class %s does not implement the requested interface %s",
	recv.getClass().getName(), refc.getName());
	throw new IncompatibleClassChangeError(msg);
	}
	return recv;
	}
	}

	/** Used for interface receiver type checks, by Interface and Special modes. */
	Object checkReceiver(Object recv) {
	throw new InternalError("Should only be invoked on a subclass");
	}


	/** This subclass handles constructor references. */
	static class Constructor extends DirectMethodHandle {
	final MemberName initMethod;
	final Class<?> instanceClass;

	private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
	MemberName initMethod, Class<?> instanceClass) {
	super(mtype, form, constructor);
	this.initMethod = initMethod;
	this.instanceClass = instanceClass;
	assert(initMethod.isResolved());
	}
	@Override
	MethodHandle copyWith(MethodType mt, LambdaForm lf) {
	return new Constructor(mt, lf, member, initMethod, instanceClass);
	}
	}

	/non-public/ static Object constructorMethod(Object mh) {
	Constructor dmh = (Constructor)mh;
	return dmh.initMethod;
	}

	/non-public/ static Object allocateInstance(Object mh) throws InstantiationException {
	Constructor dmh = (Constructor)mh;
	return UNSAFE.allocateInstance(dmh.instanceClass);
	}

	/** This subclass handles non-static field references. */
	static class Accessor extends DirectMethodHandle {
	final Class<?> fieldType;
	final int fieldOffset;
	private Accessor(MethodType mtype, LambdaForm form, MemberName member,
	int fieldOffset) {
	super(mtype, form, member);
	this.fieldType = member.getFieldType();
	this.fieldOffset = fieldOffset;
	}

	@Override Object checkCast(Object obj) {
	return fieldType.cast(obj);
	}
	@Override
	MethodHandle copyWith(MethodType mt, LambdaForm lf) {
	return new Accessor(mt, lf, member, fieldOffset);
	}
	}

	@ForceInline
	/non-public/ static long fieldOffset(Object accessorObj) {
	// Note: We return a long because that is what Unsafe.getObject likes.
	// We store a plain int because it is more compact.
	return ((Accessor)accessorObj).fieldOffset;
	}

	@ForceInline
	/non-public/ static Object checkBase(Object obj) {
	// Note that the object's class has already been verified,
	// since the parameter type of the Accessor method handle
	// is either member.getDeclaringClass or a subclass.
	// This was verified in DirectMethodHandle.make.
	// Therefore, the only remaining check is for null.
	// Since this check is not guaranteed by Unsafe.getInt
	// and its siblings, we need to make an explicit one here.
	return Objects.requireNonNull(obj);
	}

	/** This subclass handles static field references. */
	static class StaticAccessor extends DirectMethodHandle {
	private final Class<?> fieldType;
	private final Object staticBase;
	private final long staticOffset;

	private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
	Object staticBase, long staticOffset) {
	super(mtype, form, member);
	this.fieldType = member.getFieldType();
	this.staticBase = staticBase;
	this.staticOffset = staticOffset;
	}

	@Override Object checkCast(Object obj) {
	return fieldType.cast(obj);
	}
	@Override
	MethodHandle copyWith(MethodType mt, LambdaForm lf) {
	return new StaticAccessor(mt, lf, member, staticBase, staticOffset);
	}
	}

	@ForceInline
	/non-public/ static Object nullCheck(Object obj) {
	return Objects.requireNonNull(obj);
	}

	@ForceInline
	/non-public/ static Object staticBase(Object accessorObj) {
	return ((StaticAccessor)accessorObj).staticBase;
	}

	@ForceInline
	/non-public/ static long staticOffset(Object accessorObj) {
	return ((StaticAccessor)accessorObj).staticOffset;
	}

	@ForceInline
	/non-public/ static Object checkCast(Object mh, Object obj) {
	return ((DirectMethodHandle) mh).checkCast(obj);
	}

	Object checkCast(Object obj) {
	return member.getReturnType().cast(obj);
	}

	// Caching machinery for field accessors:
	static final byte
	AF_GETFIELD = 0,
	AF_PUTFIELD = 1,
	AF_GETSTATIC = 2,
	AF_PUTSTATIC = 3,
	AF_GETSTATIC_INIT = 4,
	AF_PUTSTATIC_INIT = 5,
	AF_LIMIT = 6;
	// Enumerate the different field kinds using Wrapper,
	// with an extra case added for checked references.
	static final int
	FT_LAST_WRAPPER = Wrapper.COUNT-1,
	FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
	FT_CHECKED_REF = FT_LAST_WRAPPER+1,
	FT_LIMIT = FT_LAST_WRAPPER+2;
	private static int afIndex(byte formOp, boolean isVolatile, int ftypeKind) {
	return ((formOp * FT_LIMIT * 2)
	+ (isVolatile ? FT_LIMIT : 0)
	+ ftypeKind);
	}
	@Stable
	private static final LambdaForm[] ACCESSOR_FORMS
	= new LambdaForm[afIndex(AF_LIMIT, false, 0)];
	static int ftypeKind(Class<?> ftype) {
	if (ftype.isPrimitive())
	return Wrapper.forPrimitiveType(ftype).ordinal();
	else if (VerifyType.isNullReferenceConversion(Object.class, ftype))
	return FT_UNCHECKED_REF;
	else
	return FT_CHECKED_REF;
	}

	/**
	* Create a LF which can access the given field.
	* Cache and share this structure among all fields with
	* the same basicType and refKind.
	*/
	private static LambdaForm preparedFieldLambdaForm(MemberName m) {
	Class<?> ftype = m.getFieldType();
	boolean isVolatile = m.isVolatile();
	byte formOp;
	switch (m.getReferenceKind()) {
	case REF_getField: formOp = AF_GETFIELD; break;
	case REF_putField: formOp = AF_PUTFIELD; break;
	case REF_getStatic: formOp = AF_GETSTATIC; break;
	case REF_putStatic: formOp = AF_PUTSTATIC; break;
	default: throw new InternalError(m.toString());
	}
	if (shouldBeInitialized(m)) {
	// precompute the barrier-free version:
	preparedFieldLambdaForm(formOp, isVolatile, ftype);
	assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
	(AF_PUTSTATIC_INIT - AF_PUTSTATIC));
	formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
	}
	LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, ftype);
	maybeCompile(lform, m);
	assert(lform.methodType().dropParameterTypes(0, 1)
	.equals(m.getInvocationType().basicType()))
	: Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
	return lform;
	}
	private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, Class<?> ftype) {
	int ftypeKind = ftypeKind(ftype);
	int afIndex = afIndex(formOp, isVolatile, ftypeKind);
	LambdaForm lform = ACCESSOR_FORMS[afIndex];
	if (lform != null) return lform;
	lform = makePreparedFieldLambdaForm(formOp, isVolatile, ftypeKind);
	ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
	return lform;
	}

	private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();

	private static Kind getFieldKind(boolean isGetter, boolean isVolatile, Wrapper wrapper) {
	if (isGetter) {
	if (isVolatile) {
	switch (wrapper) {
	case BOOLEAN: return GET_BOOLEAN_VOLATILE;
	case BYTE: return GET_BYTE_VOLATILE;
	case SHORT: return GET_SHORT_VOLATILE;
	case CHAR: return GET_CHAR_VOLATILE;
	case INT: return GET_INT_VOLATILE;
	case LONG: return GET_LONG_VOLATILE;
	case FLOAT: return GET_FLOAT_VOLATILE;
	case DOUBLE: return GET_DOUBLE_VOLATILE;
	case OBJECT: return GET_OBJECT_VOLATILE;
	}
	} else {
	switch (wrapper) {
	case BOOLEAN: return GET_BOOLEAN;
	case BYTE: return GET_BYTE;
	case SHORT: return GET_SHORT;
	case CHAR: return GET_CHAR;
	case INT: return GET_INT;
	case LONG: return GET_LONG;
	case FLOAT: return GET_FLOAT;
	case DOUBLE: return GET_DOUBLE;
	case OBJECT: return GET_OBJECT;
	}
	}
	} else {
	if (isVolatile) {
	switch (wrapper) {
	case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
	case BYTE: return PUT_BYTE_VOLATILE;
	case SHORT: return PUT_SHORT_VOLATILE;
	case CHAR: return PUT_CHAR_VOLATILE;
	case INT: return PUT_INT_VOLATILE;
	case LONG: return PUT_LONG_VOLATILE;
	case FLOAT: return PUT_FLOAT_VOLATILE;
	case DOUBLE: return PUT_DOUBLE_VOLATILE;
	case OBJECT: return PUT_OBJECT_VOLATILE;
	}
	} else {
	switch (wrapper) {
	case BOOLEAN: return PUT_BOOLEAN;
	case BYTE: return PUT_BYTE;
	case SHORT: return PUT_SHORT;
	case CHAR: return PUT_CHAR;
	case INT: return PUT_INT;
	case LONG: return PUT_LONG;
	case FLOAT: return PUT_FLOAT;
	case DOUBLE: return PUT_DOUBLE;
	case OBJECT: return PUT_OBJECT;
	}
	}
	}
	throw new AssertionError("Invalid arguments");
	}

	static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftypeKind) {
	boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
	boolean isStatic = (formOp >= AF_GETSTATIC);
	boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
	boolean needsCast = (ftypeKind == FT_CHECKED_REF);
	Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
	Class<?> ft = fw.primitiveType();
	assert(ftypeKind(needsCast ? String.class : ft) == ftypeKind);

	// getObject, putIntVolatile, etc.
	Kind kind = getFieldKind(isGetter, isVolatile, fw);

	MethodType linkerType;
	if (isGetter)
	linkerType = MethodType.methodType(ft, Object.class, long.class);
	else
	linkerType = MethodType.methodType(void.class, Object.class, long.class, ft);
	MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
	try {
	linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, NoSuchMethodException.class);
	} catch (ReflectiveOperationException ex) {
	throw newInternalError(ex);
	}

	// What is the external type of the lambda form?
	MethodType mtype;
	if (isGetter)
	mtype = MethodType.methodType(ft);
	else
	mtype = MethodType.methodType(void.class, ft);
	mtype = mtype.basicType(); // erase short to int, etc.
	if (!isStatic)
	mtype = mtype.insertParameterTypes(0, Object.class);
	final int DMH_THIS = 0;
	final int ARG_BASE = 1;
	final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
	// if this is for non-static access, the base pointer is stored at this index:
	final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
	// if this is for write access, the value to be written is stored at this index:
	final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
	int nameCursor = ARG_LIMIT;
	final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
	final int F_OFFSET = nameCursor++; // Either static offset or field offset.
	final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
	final int U_HOLDER = nameCursor++; // UNSAFE holder
	final int INIT_BAR = (needsInit ? nameCursor++ : -1);
	final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
	final int LINKER_CALL = nameCursor++;
	final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
	final int RESULT = nameCursor-1; // either the call or the cast
	Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
	if (needsInit)
	names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
	if (needsCast && !isGetter)
	names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
	Object[] outArgs = new Object[1 + linkerType.parameterCount()];
	assert(outArgs.length == (isGetter ? 3 : 4));
	outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
	if (isStatic) {
	outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
	outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
	} else {
	outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
	outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
	}
	if (!isGetter) {
	outArgs[3] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
	}
	for (Object a : outArgs) assert(a != null);
	names[LINKER_CALL] = new Name(linker, outArgs);
	if (needsCast && isGetter)
	names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);
	for (Name n : names) assert(n != null);

	LambdaForm form;
	if (needsCast \|\| needsInit) {
	// can't use the pre-generated form when casting and/or initializing
	form = new LambdaForm(ARG_LIMIT, names, RESULT);
	} else {
	form = new LambdaForm(ARG_LIMIT, names, RESULT, kind);
	}

	if (LambdaForm.debugNames()) {
	// add some detail to the lambdaForm debugname,
	// significant only for debugging
	StringBuilder nameBuilder = new StringBuilder(kind.methodName);
	if (isStatic) {
	nameBuilder.append("Static");
	} else {
	nameBuilder.append("Field");
	}
	if (needsCast) {
	nameBuilder.append("Cast");
	}
	if (needsInit) {
	nameBuilder.append("Init");
	}
	LambdaForm.associateWithDebugName(form, nameBuilder.toString());
	}
	return form;
	}

	/**
	* Pre-initialized NamedFunctions for bootstrapping purposes.
	*/
	static final byte NF_internalMemberName = 0,
	NF_internalMemberNameEnsureInit = 1,
	NF_ensureInitialized = 2,
	NF_fieldOffset = 3,
	NF_checkBase = 4,
	NF_staticBase = 5,
	NF_staticOffset = 6,
	NF_checkCast = 7,
	NF_allocateInstance = 8,
	NF_constructorMethod = 9,
	NF_UNSAFE = 10,
	NF_checkReceiver = 11,
	NF_LIMIT = 12;

	private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];

	private static NamedFunction getFunction(byte func) {
	NamedFunction nf = NFS[func];
	if (nf != null) {
	return nf;
	}
	// Each nf must be statically invocable or we get tied up in our bootstraps.
	nf = NFS[func] = createFunction(func);
	assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
	return nf;
	}

	private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);

	private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);

	private static NamedFunction createFunction(byte func) {
	try {
	switch (func) {
	case NF_internalMemberName:
	return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
	case NF_internalMemberNameEnsureInit:
	return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
	case NF_ensureInitialized:
	return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
	case NF_fieldOffset:
	return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
	case NF_checkBase:
	return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
	case NF_staticBase:
	return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
	case NF_staticOffset:
	return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
	case NF_checkCast:
	return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
	case NF_allocateInstance:
	return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
	case NF_constructorMethod:
	return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
	case NF_UNSAFE:
	MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getField);
	return new NamedFunction(
	MemberName.getFactory()
	.resolveOrFail(REF_getField, member, DirectMethodHandle.class, NoSuchMethodException.class));
	case NF_checkReceiver:
	member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
	return new NamedFunction(
	MemberName.getFactory()
	.resolveOrFail(REF_invokeVirtual, member, DirectMethodHandle.class, NoSuchMethodException.class));
	default:
	throw newInternalError("Unknown function: " + func);
	}
	} catch (ReflectiveOperationException ex) {
	throw newInternalError(ex);
	}
	}

	private static NamedFunction getNamedFunction(String name, MethodType type)
	throws ReflectiveOperationException
	{
	MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
	return new NamedFunction(
	MemberName.getFactory()
	.resolveOrFail(REF_invokeStatic, member, DirectMethodHandle.class, NoSuchMethodException.class));
	}

	static {
	// The Holder class will contain pre-generated DirectMethodHandles resolved
	// speculatively using MemberName.getFactory().resolveOrNull. However, that
	// doesn't initialize the class, which subtly breaks inlining etc. By forcing
	// initialization of the Holder class we avoid these issues.
	UNSAFE.ensureClassInitialized(Holder.class);
	}

	/* Placeholder class for DirectMethodHandles generated ahead of time */
	final class Holder {}
	}

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