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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.ref.CleanerFactory;
	import sun.invoke.util.Wrapper;

	import java.lang.invoke.MethodHandles.Lookup;
	import java.lang.reflect.Field;

	import static java.lang.invoke.MethodHandleNatives.Constants.*;
	import static java.lang.invoke.MethodHandleStatics.TRACE_METHOD_LINKAGE;
	import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;

	/**
	* The JVM interface for the method handles package is all here.
	* This is an interface internal and private to an implementation of JSR 292.
	* <em>This class is not part of the JSR 292 standard.</em>
	* @author jrose
	*/
	class MethodHandleNatives {

	private MethodHandleNatives() { } // static only

	/// MemberName support

	static native void init(MemberName self, Object ref);
	static native void expand(MemberName self);
	static native MemberName resolve(MemberName self, Class<?> caller,
	boolean speculativeResolve) throws LinkageError, ClassNotFoundException;
	static native int getMembers(Class<?> defc, String matchName, String matchSig,
	int matchFlags, Class<?> caller, int skip, MemberName[] results);

	/// Field layout queries parallel to jdk.internal.misc.Unsafe:
	static native long objectFieldOffset(MemberName self); // e.g., returns vmindex
	static native long staticFieldOffset(MemberName self); // e.g., returns vmindex
	static native Object staticFieldBase(MemberName self); // e.g., returns clazz
	static native Object getMemberVMInfo(MemberName self); // returns {vmindex,vmtarget}

	/// CallSite support

	/** Tell the JVM that we need to change the target of a CallSite. */
	static native void setCallSiteTargetNormal(CallSite site, MethodHandle target);
	static native void setCallSiteTargetVolatile(CallSite site, MethodHandle target);

	static native void copyOutBootstrapArguments(Class<?> caller, int[] indexInfo,
	int start, int end,
	Object[] buf, int pos,
	boolean resolve,
	Object ifNotAvailable);

	/** Represents a context to track nmethod dependencies on CallSite instance target. */
	static class CallSiteContext implements Runnable {
	//@Injected JVM_nmethodBucket* vmdependencies;

	static CallSiteContext make(CallSite cs) {
	final CallSiteContext newContext = new CallSiteContext();
	// CallSite instance is tracked by a Cleanable which clears native
	// structures allocated for CallSite context. Though the CallSite can
	// become unreachable, its Context is retained by the Cleanable instance
	// (which is referenced from Cleaner instance which is referenced from
	// CleanerFactory class) until cleanup is performed.
	CleanerFactory.cleaner().register(cs, newContext);
	return newContext;
	}

	@Override
	public void run() {
	MethodHandleNatives.clearCallSiteContext(this);
	}
	}

	/** Invalidate all recorded nmethods. */
	private static native void clearCallSiteContext(CallSiteContext context);

	private static native void registerNatives();
	static {
	registerNatives();
	}

	/**
	* Compile-time constants go here. This collection exists not only for
	* reference from clients, but also for ensuring the VM and JDK agree on the
	* values of these constants (see {@link #verifyConstants()}).
	*/
	static class Constants {
	Constants() { } // static only

	static final int
	MN_IS_METHOD = 0x00010000, // method (not constructor)
	MN_IS_CONSTRUCTOR = 0x00020000, // constructor
	MN_IS_FIELD = 0x00040000, // field
	MN_IS_TYPE = 0x00080000, // nested type
	MN_CALLER_SENSITIVE = 0x00100000, // @CallerSensitive annotation detected
	MN_REFERENCE_KIND_SHIFT = 24, // refKind
	MN_REFERENCE_KIND_MASK = 0x0F000000 >> MN_REFERENCE_KIND_SHIFT,
	// The SEARCH_* bits are not for MN.flags but for the matchFlags argument of MHN.getMembers:
	MN_SEARCH_SUPERCLASSES = 0x00100000,
	MN_SEARCH_INTERFACES = 0x00200000;

	/**
	* Constant pool reference-kind codes, as used by CONSTANT_MethodHandle CP entries.
	*/
	static final byte
	REF_NONE = 0, // null value
	REF_getField = 1,
	REF_getStatic = 2,
	REF_putField = 3,
	REF_putStatic = 4,
	REF_invokeVirtual = 5,
	REF_invokeStatic = 6,
	REF_invokeSpecial = 7,
	REF_newInvokeSpecial = 8,
	REF_invokeInterface = 9,
	REF_LIMIT = 10;
	}

	static boolean refKindIsValid(int refKind) {
	return (refKind > REF_NONE && refKind < REF_LIMIT);
	}
	static boolean refKindIsField(byte refKind) {
	assert(refKindIsValid(refKind));
	return (refKind <= REF_putStatic);
	}
	static boolean refKindIsGetter(byte refKind) {
	assert(refKindIsValid(refKind));
	return (refKind <= REF_getStatic);
	}
	static boolean refKindIsSetter(byte refKind) {
	return refKindIsField(refKind) && !refKindIsGetter(refKind);
	}
	static boolean refKindIsMethod(byte refKind) {
	return !refKindIsField(refKind) && (refKind != REF_newInvokeSpecial);
	}
	static boolean refKindIsConstructor(byte refKind) {
	return (refKind == REF_newInvokeSpecial);
	}
	static boolean refKindHasReceiver(byte refKind) {
	assert(refKindIsValid(refKind));
	return (refKind & 1) != 0;
	}
	static boolean refKindIsStatic(byte refKind) {
	return !refKindHasReceiver(refKind) && (refKind != REF_newInvokeSpecial);
	}
	static boolean refKindDoesDispatch(byte refKind) {
	assert(refKindIsValid(refKind));
	return (refKind == REF_invokeVirtual \|\|
	refKind == REF_invokeInterface);
	}
	static {
	final int HR_MASK = ((1 << REF_getField) \|
	(1 << REF_putField) \|
	(1 << REF_invokeVirtual) \|
	(1 << REF_invokeSpecial) \|
	(1 << REF_invokeInterface)
	);
	for (byte refKind = REF_NONE+1; refKind < REF_LIMIT; refKind++) {
	assert(refKindHasReceiver(refKind) == (((1<<refKind) & HR_MASK) != 0)) : refKind;
	}
	}
	static String refKindName(byte refKind) {
	assert(refKindIsValid(refKind));
	switch (refKind) {
	case REF_getField: return "getField";
	case REF_getStatic: return "getStatic";
	case REF_putField: return "putField";
	case REF_putStatic: return "putStatic";
	case REF_invokeVirtual: return "invokeVirtual";
	case REF_invokeStatic: return "invokeStatic";
	case REF_invokeSpecial: return "invokeSpecial";
	case REF_newInvokeSpecial: return "newInvokeSpecial";
	case REF_invokeInterface: return "invokeInterface";
	default: return "REF_???";
	}
	}

	private static native int getNamedCon(int which, Object[] name);
	static boolean verifyConstants() {
	Object[] box = { null };
	for (int i = 0; ; i++) {
	box[0] = null;
	int vmval = getNamedCon(i, box);
	if (box[0] == null) break;
	String name = (String) box[0];
	try {
	Field con = Constants.class.getDeclaredField(name);
	int jval = con.getInt(null);
	if (jval == vmval) continue;
	String err = (name+": JVM has "+vmval+" while Java has "+jval);
	if (name.equals("CONV_OP_LIMIT")) {
	System.err.println("warning: "+err);
	continue;
	}
	throw new InternalError(err);
	} catch (NoSuchFieldException \| IllegalAccessException ex) {
	String err = (name+": JVM has "+vmval+" which Java does not define");
	// ignore exotic ops the JVM cares about; we just wont issue them
	//System.err.println("warning: "+err);
	continue;
	}
	}
	return true;
	}
	static {
	assert(verifyConstants());
	}

	// Up-calls from the JVM.
	// These must NOT be public.

	/**
	* The JVM is linking an invokedynamic instruction. Create a reified call site for it.
	*/
	static MemberName linkCallSite(Object callerObj,
	int indexInCP,
	Object bootstrapMethodObj,
	Object nameObj, Object typeObj,
	Object staticArguments,
	Object[] appendixResult) {
	MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj;
	Class<?> caller = (Class<?>)callerObj;
	String name = nameObj.toString().intern();
	MethodType type = (MethodType)typeObj;
	if (!TRACE_METHOD_LINKAGE)
	return linkCallSiteImpl(caller, bootstrapMethod, name, type,
	staticArguments, appendixResult);
	return linkCallSiteTracing(caller, bootstrapMethod, name, type,
	staticArguments, appendixResult);
	}
	static MemberName linkCallSiteImpl(Class<?> caller,
	MethodHandle bootstrapMethod,
	String name, MethodType type,
	Object staticArguments,
	Object[] appendixResult) {
	CallSite callSite = CallSite.makeSite(bootstrapMethod,
	name,
	type,
	staticArguments,
	caller);
	if (callSite instanceof ConstantCallSite) {
	appendixResult[0] = callSite.dynamicInvoker();
	return Invokers.linkToTargetMethod(type);
	} else {
	appendixResult[0] = callSite;
	return Invokers.linkToCallSiteMethod(type);
	}
	}
	// Tracing logic:
	static MemberName linkCallSiteTracing(Class<?> caller,
	MethodHandle bootstrapMethod,
	String name, MethodType type,
	Object staticArguments,
	Object[] appendixResult) {
	Object bsmReference = bootstrapMethod.internalMemberName();
	if (bsmReference == null) bsmReference = bootstrapMethod;
	String staticArglist = staticArglistForTrace(staticArguments);
	System.out.println("linkCallSite "+caller.getName()+" "+
	bsmReference+" "+
	name+type+"/"+staticArglist);
	try {
	MemberName res = linkCallSiteImpl(caller, bootstrapMethod, name, type,
	staticArguments, appendixResult);
	System.out.println("linkCallSite => "+res+" + "+appendixResult[0]);
	return res;
	} catch (Throwable ex) {
	ex.printStackTrace(); // print now in case exception is swallowed
	System.out.println("linkCallSite => throw "+ex);
	throw ex;
	}
	}

	// this implements the upcall from the JVM, MethodHandleNatives.linkDynamicConstant:
	static Object linkDynamicConstant(Object callerObj,
	int indexInCP,
	Object bootstrapMethodObj,
	Object nameObj, Object typeObj,
	Object staticArguments) {
	MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj;
	Class<?> caller = (Class<?>)callerObj;
	String name = nameObj.toString().intern();
	Class<?> type = (Class<?>)typeObj;
	if (!TRACE_METHOD_LINKAGE)
	return linkDynamicConstantImpl(caller, bootstrapMethod, name, type, staticArguments);
	return linkDynamicConstantTracing(caller, bootstrapMethod, name, type, staticArguments);
	}

	static Object linkDynamicConstantImpl(Class<?> caller,
	MethodHandle bootstrapMethod,
	String name, Class<?> type,
	Object staticArguments) {
	return ConstantBootstraps.makeConstant(bootstrapMethod, name, type, staticArguments, caller);
	}

	private static String staticArglistForTrace(Object staticArguments) {
	if (staticArguments instanceof Object[])
	return "BSA="+java.util.Arrays.asList((Object[]) staticArguments);
	if (staticArguments instanceof int[])
	return "BSA@"+java.util.Arrays.toString((int[]) staticArguments);
	if (staticArguments == null)
	return "BSA0=null";
	return "BSA1="+staticArguments;
	}

	// Tracing logic:
	static Object linkDynamicConstantTracing(Class<?> caller,
	MethodHandle bootstrapMethod,
	String name, Class<?> type,
	Object staticArguments) {
	Object bsmReference = bootstrapMethod.internalMemberName();
	if (bsmReference == null) bsmReference = bootstrapMethod;
	String staticArglist = staticArglistForTrace(staticArguments);
	System.out.println("linkDynamicConstant "+caller.getName()+" "+
	bsmReference+" "+
	name+type+"/"+staticArglist);
	try {
	Object res = linkDynamicConstantImpl(caller, bootstrapMethod, name, type, staticArguments);
	System.out.println("linkDynamicConstantImpl => "+res);
	return res;
	} catch (Throwable ex) {
	ex.printStackTrace(); // print now in case exception is swallowed
	System.out.println("linkDynamicConstant => throw "+ex);
	throw ex;
	}
	}

	/** The JVM is requesting pull-mode bootstrap when it provides
	* a tuple of the form int[]{ argc, vmindex }.
	* The BSM is expected to call back to the JVM using the caller
	* class and vmindex to resolve the static arguments.
	*/
	static boolean staticArgumentsPulled(Object staticArguments) {
	return staticArguments instanceof int[];
	}

	/** A BSM runs in pull-mode if and only if its sole arguments
	* are (Lookup, BootstrapCallInfo), or can be converted pairwise
	* to those types, and it is not of variable arity.
	* Excluding error cases, we can just test that the arity is a constant 2.
	*
	* NOTE: This method currently returns false, since pulling is not currently
	* exposed to a BSM. When pull mode is supported the method block will be
	* replaced with currently commented out code.
	*/
	static boolean isPullModeBSM(MethodHandle bsm) {
	return false;
	// return bsm.type().parameterCount() == 2 && !bsm.isVarargsCollector();
	}

	/**
	* The JVM wants a pointer to a MethodType. Oblige it by finding or creating one.
	*/
	static MethodType findMethodHandleType(Class<?> rtype, Class<?>[] ptypes) {
	return MethodType.makeImpl(rtype, ptypes, true);
	}

	/**
	* The JVM wants to link a call site that requires a dynamic type check.
	* Name is a type-checking invoker, invokeExact or invoke.
	* Return a JVM method (MemberName) to handle the invoking.
	* The method assumes the following arguments on the stack:
	* 0: the method handle being invoked
	* 1-N: the arguments to the method handle invocation
	* N+1: an optional, implicitly added argument (typically the given MethodType)
	* <p>
	* The nominal method at such a call site is an instance of
	* a signature-polymorphic method (see @PolymorphicSignature).
	* Such method instances are user-visible entities which are
	* "split" from the generic placeholder method in {@code MethodHandle}.
	* (Note that the placeholder method is not identical with any of
	* its instances. If invoked reflectively, is guaranteed to throw an
	* {@code UnsupportedOperationException}.)
	* If the signature-polymorphic method instance is ever reified,
	* it appears as a "copy" of the original placeholder
	* (a native final member of {@code MethodHandle}) except
	* that its type descriptor has shape required by the instance,
	* and the method instance is <em>not</em> varargs.
	* The method instance is also marked synthetic, since the
	* method (by definition) does not appear in Java source code.
	* <p>
	* The JVM is allowed to reify this method as instance metadata.
	* For example, {@code invokeBasic} is always reified.
	* But the JVM may instead call {@code linkMethod}.
	* If the result is an * ordered pair of a {@code (method, appendix)},
	* the method gets all the arguments (0..N inclusive)
	* plus the appendix (N+1), and uses the appendix to complete the call.
	* In this way, one reusable method (called a "linker method")
	* can perform the function of any number of polymorphic instance
	* methods.
	* <p>
	* Linker methods are allowed to be weakly typed, with any or
	* all references rewritten to {@code Object} and any primitives
	* (except {@code long}/{@code float}/{@code double})
	* rewritten to {@code int}.
	* A linker method is trusted to return a strongly typed result,
	* according to the specific method type descriptor of the
	* signature-polymorphic instance it is emulating.
	* This can involve (as necessary) a dynamic check using
	* data extracted from the appendix argument.
	* <p>
	* The JVM does not inspect the appendix, other than to pass
	* it verbatim to the linker method at every call.
	* This means that the JDK runtime has wide latitude
	* for choosing the shape of each linker method and its
	* corresponding appendix.
	* Linker methods should be generated from {@code LambdaForm}s
	* so that they do not become visible on stack traces.
	* <p>
	* The {@code linkMethod} call is free to omit the appendix
	* (returning null) and instead emulate the required function
	* completely in the linker method.
	* As a corner case, if N==255, no appendix is possible.
	* In this case, the method returned must be custom-generated to
	* to perform any needed type checking.
	* <p>
	* If the JVM does not reify a method at a call site, but instead
	* calls {@code linkMethod}, the corresponding call represented
	* in the bytecodes may mention a valid method which is not
	* representable with a {@code MemberName}.
	* Therefore, use cases for {@code linkMethod} tend to correspond to
	* special cases in reflective code such as {@code findVirtual}
	* or {@code revealDirect}.
	*/
	static MemberName linkMethod(Class<?> callerClass, int refKind,
	Class<?> defc, String name, Object type,
	Object[] appendixResult) {
	if (!TRACE_METHOD_LINKAGE)
	return linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult);
	return linkMethodTracing(callerClass, refKind, defc, name, type, appendixResult);
	}
	static MemberName linkMethodImpl(Class<?> callerClass, int refKind,
	Class<?> defc, String name, Object type,
	Object[] appendixResult) {
	try {
	if (refKind == REF_invokeVirtual) {
	if (defc == MethodHandle.class) {
	return Invokers.methodHandleInvokeLinkerMethod(
	name, fixMethodType(callerClass, type), appendixResult);
	} else if (defc == VarHandle.class) {
	return varHandleOperationLinkerMethod(
	name, fixMethodType(callerClass, type), appendixResult);
	}
	}
	} catch (Error e) {
	// Pass through an Error, including say StackOverflowError or
	// OutOfMemoryError
	throw e;
	} catch (Throwable ex) {
	// Wrap anything else in LinkageError
	throw new LinkageError(ex.getMessage(), ex);
	}
	throw new LinkageError("no such method "+defc.getName()+"."+name+type);
	}
	private static MethodType fixMethodType(Class<?> callerClass, Object type) {
	if (type instanceof MethodType)
	return (MethodType) type;
	else
	return MethodType.fromDescriptor((String)type, callerClass.getClassLoader());
	}
	// Tracing logic:
	static MemberName linkMethodTracing(Class<?> callerClass, int refKind,
	Class<?> defc, String name, Object type,
	Object[] appendixResult) {
	System.out.println("linkMethod "+defc.getName()+"."+
	name+type+"/"+Integer.toHexString(refKind));
	try {
	MemberName res = linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult);
	System.out.println("linkMethod => "+res+" + "+appendixResult[0]);
	return res;
	} catch (Throwable ex) {
	System.out.println("linkMethod => throw "+ex);
	throw ex;
	}
	}

	/**
	* Obtain the method to link to the VarHandle operation.
	* This method is located here and not in Invokers to avoid
	* intializing that and other classes early on in VM bootup.
	*/
	private static MemberName varHandleOperationLinkerMethod(String name,
	MethodType mtype,
	Object[] appendixResult) {
	// Get the signature method type
	final MethodType sigType = mtype.basicType();

	// Get the access kind from the method name
	VarHandle.AccessMode ak;
	try {
	ak = VarHandle.AccessMode.valueFromMethodName(name);
	} catch (IllegalArgumentException e) {
	throw MethodHandleStatics.newInternalError(e);
	}

	// Create the appendix descriptor constant
	VarHandle.AccessDescriptor ad = new VarHandle.AccessDescriptor(mtype, ak.at.ordinal(), ak.ordinal());
	appendixResult[0] = ad;

	if (MethodHandleStatics.VAR_HANDLE_GUARDS) {
	// If not polymorphic in the return type, such as the compareAndSet
	// methods that return boolean
	Class<?> guardReturnType = sigType.returnType();
	if (ak.at.isMonomorphicInReturnType) {
	if (ak.at.returnType != mtype.returnType()) {
	// The caller contains a different return type than that
	// defined by the method
	throw newNoSuchMethodErrorOnVarHandle(name, mtype);
	}
	// Adjust the return type of the signature method type
	guardReturnType = ak.at.returnType;
	}

	// Get the guard method type for linking
	final Class<?>[] guardParams = new Class<?>[sigType.parameterCount() + 2];
	// VarHandle at start
	guardParams[0] = VarHandle.class;
	for (int i = 0; i < sigType.parameterCount(); i++) {
	guardParams[i + 1] = sigType.parameterType(i);
	}
	// Access descriptor at end
	guardParams[guardParams.length - 1] = VarHandle.AccessDescriptor.class;
	MethodType guardType = MethodType.makeImpl(guardReturnType, guardParams, true);

	MemberName linker = new MemberName(
	VarHandleGuards.class, getVarHandleGuardMethodName(guardType),
	guardType, REF_invokeStatic);

	linker = MemberName.getFactory().resolveOrNull(REF_invokeStatic, linker,
	VarHandleGuards.class);
	if (linker != null) {
	return linker;
	}
	// Fall back to lambda form linkage if guard method is not available
	// TODO Optionally log fallback ?
	}
	return Invokers.varHandleInvokeLinkerMethod(ak, mtype);
	}
	static String getVarHandleGuardMethodName(MethodType guardType) {
	String prefix = "guard_";
	StringBuilder sb = new StringBuilder(prefix.length() + guardType.parameterCount());

	sb.append(prefix);
	for (int i = 1; i < guardType.parameterCount() - 1; i++) {
	Class<?> pt = guardType.parameterType(i);
	sb.append(getCharType(pt));
	}
	sb.append('_').append(getCharType(guardType.returnType()));
	return sb.toString();
	}
	static char getCharType(Class<?> pt) {
	return Wrapper.forBasicType(pt).basicTypeChar();
	}
	static NoSuchMethodError newNoSuchMethodErrorOnVarHandle(String name, MethodType mtype) {
	return new NoSuchMethodError("VarHandle." + name + mtype);
	}

	/**
	* The JVM is resolving a CONSTANT_MethodHandle CP entry. And it wants our help.
	* It will make an up-call to this method. (Do not change the name or signature.)
	* The type argument is a Class for field requests and a MethodType for non-fields.
	* <p>
	* Recent versions of the JVM may also pass a resolved MemberName for the type.
	* In that case, the name is ignored and may be null.
	*/
	static MethodHandle linkMethodHandleConstant(Class<?> callerClass, int refKind,
	Class<?> defc, String name, Object type) {
	try {
	Lookup lookup = IMPL_LOOKUP.in(callerClass);
	assert(refKindIsValid(refKind));
	return lookup.linkMethodHandleConstant((byte) refKind, defc, name, type);
	} catch (ReflectiveOperationException ex) {
	throw mapLookupExceptionToError(ex);
	}
	}

	/**
	* Map a reflective exception to a linkage error.
	*/
	static LinkageError mapLookupExceptionToError(ReflectiveOperationException ex) {
	LinkageError err;
	if (ex instanceof IllegalAccessException) {
	Throwable cause = ex.getCause();
	if (cause instanceof AbstractMethodError) {
	return (AbstractMethodError) cause;
	} else {
	err = new IllegalAccessError(ex.getMessage());
	}
	} else if (ex instanceof NoSuchMethodException) {
	err = new NoSuchMethodError(ex.getMessage());
	} else if (ex instanceof NoSuchFieldException) {
	err = new NoSuchFieldError(ex.getMessage());
	} else {
	err = new IncompatibleClassChangeError();
	}
	return initCauseFrom(err, ex);
	}

	/**
	* Use best possible cause for err.initCause(), substituting the
	* cause for err itself if the cause has the same (or better) type.
	*/
	static <E extends Error> E initCauseFrom(E err, Exception ex) {
	Throwable th = ex.getCause();
	@SuppressWarnings("unchecked")
	final Class<E> Eclass = (Class<E>) err.getClass();
	if (Eclass.isInstance(th))
	return Eclass.cast(th);
	err.initCause(th == null ? ex : th);
	return err;
	}

	/**
	* Is this method a caller-sensitive method?
	* I.e., does it call Reflection.getCallerClass or a similar method
	* to ask about the identity of its caller?
	*/
	static boolean isCallerSensitive(MemberName mem) {
	if (!mem.isInvocable()) return false; // fields are not caller sensitive

	return mem.isCallerSensitive() \|\| canBeCalledVirtual(mem);
	}

	static boolean canBeCalledVirtual(MemberName mem) {
	assert(mem.isInvocable());
	switch (mem.getName()) {
	case "getContextClassLoader":
	return canBeCalledVirtual(mem, java.lang.Thread.class);
	}
	return false;
	}

	static boolean canBeCalledVirtual(MemberName symbolicRef, Class<?> definingClass) {
	Class<?> symbolicRefClass = symbolicRef.getDeclaringClass();
	if (symbolicRefClass == definingClass) return true;
	if (symbolicRef.isStatic() \|\| symbolicRef.isPrivate()) return false;
	return (definingClass.isAssignableFrom(symbolicRefClass) \|\| // Msym overrides Mdef
	symbolicRefClass.isInterface()); // Mdef implements Msym
	}
	}

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