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	/*
	* Copyright (c) 2008, 2013, 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 static jdk.internal.org.objectweb.asm.Opcodes.*;
	import static java.lang.invoke.LambdaForm.*;
	import static java.lang.invoke.LambdaForm.BasicType.*;
	import static java.lang.invoke.MethodHandleStatics.*;

	import java.lang.invoke.LambdaForm.NamedFunction;
	import java.lang.invoke.MethodHandles.Lookup;
	import java.lang.reflect.Field;
	import java.util.Arrays;
	import java.util.function.Function;
	import java.util.concurrent.ConcurrentMap;
	import java.util.concurrent.ConcurrentHashMap;

	import jdk.internal.org.objectweb.asm.FieldVisitor;
	import sun.invoke.util.ValueConversions;
	import sun.invoke.util.Wrapper;

	import jdk.internal.org.objectweb.asm.ClassWriter;
	import jdk.internal.org.objectweb.asm.MethodVisitor;

	/**
	* The flavor of method handle which emulates an invoke instruction
	* on a predetermined argument. The JVM dispatches to the correct method
	* when the handle is created, not when it is invoked.
	*
	* All bound arguments are encapsulated in dedicated species.
	*/
	/non-public/ abstract class BoundMethodHandle extends MethodHandle {

	/non-public/ BoundMethodHandle(MethodType type, LambdaForm form) {
	super(type, form);
	assert(speciesData() == speciesData(form));
	}

	//
	// BMH API and internals
	//

	static BoundMethodHandle bindSingle(MethodType type, LambdaForm form, BasicType xtype, Object x) {
	// for some type signatures, there exist pre-defined concrete BMH classes
	try {
	switch (xtype) {
	case L_TYPE:
	return bindSingle(type, form, x); // Use known fast path.
	case I_TYPE:
	return (BoundMethodHandle) SpeciesData.EMPTY.extendWith(I_TYPE).constructor().invokeBasic(type, form, ValueConversions.widenSubword(x));
	case J_TYPE:
	return (BoundMethodHandle) SpeciesData.EMPTY.extendWith(J_TYPE).constructor().invokeBasic(type, form, (long) x);
	case F_TYPE:
	return (BoundMethodHandle) SpeciesData.EMPTY.extendWith(F_TYPE).constructor().invokeBasic(type, form, (float) x);
	case D_TYPE:
	return (BoundMethodHandle) SpeciesData.EMPTY.extendWith(D_TYPE).constructor().invokeBasic(type, form, (double) x);
	default : throw newInternalError("unexpected xtype: " + xtype);
	}
	} catch (Throwable t) {
	throw newInternalError(t);
	}
	}

	/non-public/
	LambdaFormEditor editor() {
	return form.editor();
	}

	static BoundMethodHandle bindSingle(MethodType type, LambdaForm form, Object x) {
	return Species_L.make(type, form, x);
	}

	@Override // there is a default binder in the super class, for 'L' types only
	/non-public/
	BoundMethodHandle bindArgumentL(int pos, Object value) {
	return editor().bindArgumentL(this, pos, value);
	}
	/non-public/
	BoundMethodHandle bindArgumentI(int pos, int value) {
	return editor().bindArgumentI(this, pos, value);
	}
	/non-public/
	BoundMethodHandle bindArgumentJ(int pos, long value) {
	return editor().bindArgumentJ(this, pos, value);
	}
	/non-public/
	BoundMethodHandle bindArgumentF(int pos, float value) {
	return editor().bindArgumentF(this, pos, value);
	}
	/non-public/
	BoundMethodHandle bindArgumentD(int pos, double value) {
	return editor().bindArgumentD(this, pos, value);
	}

	@Override
	BoundMethodHandle rebind() {
	if (!tooComplex()) {
	return this;
	}
	return makeReinvoker(this);
	}

	private boolean tooComplex() {
	return (fieldCount() > FIELD_COUNT_THRESHOLD \|\|
	form.expressionCount() > FORM_EXPRESSION_THRESHOLD);
	}
	private static final int FIELD_COUNT_THRESHOLD = 12; // largest convenient BMH field count
	private static final int FORM_EXPRESSION_THRESHOLD = 24; // largest convenient BMH expression count

	/**
	* A reinvoker MH has this form:
	* {@code lambda (bmh, arg) { thismh = bmh[0]; invokeBasic(thismh, arg) }}
	*/
	static BoundMethodHandle makeReinvoker(MethodHandle target) {
	LambdaForm form = DelegatingMethodHandle.makeReinvokerForm(
	target, MethodTypeForm.LF_REBIND,
	Species_L.SPECIES_DATA, Species_L.SPECIES_DATA.getterFunction(0));
	return Species_L.make(target.type(), form, target);
	}

	/**
	* Return the {@link SpeciesData} instance representing this BMH species. All subclasses must provide a
	* static field containing this value, and they must accordingly implement this method.
	*/
	/non-public/ abstract SpeciesData speciesData();

	/non-public/ static SpeciesData speciesData(LambdaForm form) {
	Object c = form.names[0].constraint;
	if (c instanceof SpeciesData)
	return (SpeciesData) c;
	// if there is no BMH constraint, then use the null constraint
	return SpeciesData.EMPTY;
	}

	/**
	* Return the number of fields in this BMH. Equivalent to speciesData().fieldCount().
	*/
	/non-public/ abstract int fieldCount();

	@Override
	Object internalProperties() {
	return "\n& BMH="+internalValues();
	}

	@Override
	final Object internalValues() {
	Object[] boundValues = new Object[speciesData().fieldCount()];
	for (int i = 0; i < boundValues.length; ++i) {
	boundValues[i] = arg(i);
	}
	return Arrays.asList(boundValues);
	}

	/non-public/ final Object arg(int i) {
	try {
	switch (speciesData().fieldType(i)) {
	case L_TYPE: return speciesData().getters[i].invokeBasic(this);
	case I_TYPE: return (int) speciesData().getters[i].invokeBasic(this);
	case J_TYPE: return (long) speciesData().getters[i].invokeBasic(this);
	case F_TYPE: return (float) speciesData().getters[i].invokeBasic(this);
	case D_TYPE: return (double) speciesData().getters[i].invokeBasic(this);
	}
	} catch (Throwable ex) {
	throw newInternalError(ex);
	}
	throw new InternalError("unexpected type: " + speciesData().typeChars+"."+i);
	}

	//
	// cloning API
	//

	/non-public/ abstract BoundMethodHandle copyWith(MethodType mt, LambdaForm lf);
	/non-public/ abstract BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg);
	/non-public/ abstract BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg);
	/non-public/ abstract BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg);
	/non-public/ abstract BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg);
	/non-public/ abstract BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg);

	//
	// concrete BMH classes required to close bootstrap loops
	//

	private // make it private to force users to access the enclosing class first
	static final class Species_L extends BoundMethodHandle {
	final Object argL0;
	private Species_L(MethodType mt, LambdaForm lf, Object argL0) {
	super(mt, lf);
	this.argL0 = argL0;
	}
	@Override
	/non-public/ SpeciesData speciesData() {
	return SPECIES_DATA;
	}
	@Override
	/non-public/ int fieldCount() {
	return 1;
	}
	/non-public/ static final SpeciesData SPECIES_DATA = new SpeciesData("L", Species_L.class);
	/non-public/ static BoundMethodHandle make(MethodType mt, LambdaForm lf, Object argL0) {
	return new Species_L(mt, lf, argL0);
	}
	@Override
	/non-public/ final BoundMethodHandle copyWith(MethodType mt, LambdaForm lf) {
	return new Species_L(mt, lf, argL0);
	}
	@Override
	/non-public/ final BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg) {
	try {
	return (BoundMethodHandle) SPECIES_DATA.extendWith(L_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);
	} catch (Throwable ex) {
	throw uncaughtException(ex);
	}
	}
	@Override
	/non-public/ final BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg) {
	try {
	return (BoundMethodHandle) SPECIES_DATA.extendWith(I_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);
	} catch (Throwable ex) {
	throw uncaughtException(ex);
	}
	}
	@Override
	/non-public/ final BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg) {
	try {
	return (BoundMethodHandle) SPECIES_DATA.extendWith(J_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);
	} catch (Throwable ex) {
	throw uncaughtException(ex);
	}
	}
	@Override
	/non-public/ final BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg) {
	try {
	return (BoundMethodHandle) SPECIES_DATA.extendWith(F_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);
	} catch (Throwable ex) {
	throw uncaughtException(ex);
	}
	}
	@Override
	/non-public/ final BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg) {
	try {
	return (BoundMethodHandle) SPECIES_DATA.extendWith(D_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);
	} catch (Throwable ex) {
	throw uncaughtException(ex);
	}
	}
	}

	//
	// BMH species meta-data
	//

	/**
	* Meta-data wrapper for concrete BMH types.
	* Each BMH type corresponds to a given sequence of basic field types (LIJFD).
	* The fields are immutable; their values are fully specified at object construction.
	* Each BMH type supplies an array of getter functions which may be used in lambda forms.
	* A BMH is constructed by cloning a shorter BMH and adding one or more new field values.
	* The shortest possible BMH has zero fields; its class is SimpleMethodHandle.
	* BMH species are not interrelated by subtyping, even though it would appear that
	* a shorter BMH could serve as a supertype of a longer one which extends it.
	*/
	static class SpeciesData {
	private final String typeChars;
	private final BasicType[] typeCodes;
	private final Class<? extends BoundMethodHandle> clazz;
	// Bootstrapping requires circular relations MH -> BMH -> SpeciesData -> MH
	// Therefore, we need a non-final link in the chain. Use array elements.
	@Stable private final MethodHandle[] constructor;
	@Stable private final MethodHandle[] getters;
	@Stable private final NamedFunction[] nominalGetters;
	@Stable private final SpeciesData[] extensions;

	/non-public/ int fieldCount() {
	return typeCodes.length;
	}
	/non-public/ BasicType fieldType(int i) {
	return typeCodes[i];
	}
	/non-public/ char fieldTypeChar(int i) {
	return typeChars.charAt(i);
	}
	Object fieldSignature() {
	return typeChars;
	}
	public Class<? extends BoundMethodHandle> fieldHolder() {
	return clazz;
	}
	public String toString() {
	return "SpeciesData<"+fieldSignature()+">";
	}

	/**
	* Return a {@link LambdaForm.Name} containing a {@link LambdaForm.NamedFunction} that
	* represents a MH bound to a generic invoker, which in turn forwards to the corresponding
	* getter.
	*/
	NamedFunction getterFunction(int i) {
	NamedFunction nf = nominalGetters[i];
	assert(nf.memberDeclaringClassOrNull() == fieldHolder());
	assert(nf.returnType() == fieldType(i));
	return nf;
	}

	NamedFunction[] getterFunctions() {
	return nominalGetters;
	}

	MethodHandle[] getterHandles() { return getters; }

	MethodHandle constructor() {
	return constructor[0];
	}

	static final SpeciesData EMPTY = new SpeciesData("", BoundMethodHandle.class);

	SpeciesData(String types, Class<? extends BoundMethodHandle> clazz) {
	this.typeChars = types;
	this.typeCodes = basicTypes(types);
	this.clazz = clazz;
	if (!INIT_DONE) {
	this.constructor = new MethodHandle[1]; // only one ctor
	this.getters = new MethodHandle[types.length()];
	this.nominalGetters = new NamedFunction[types.length()];
	} else {
	this.constructor = Factory.makeCtors(clazz, types, null);
	this.getters = Factory.makeGetters(clazz, types, null);
	this.nominalGetters = Factory.makeNominalGetters(types, null, this.getters);
	}
	this.extensions = new SpeciesData[ARG_TYPE_LIMIT];
	}

	private void initForBootstrap() {
	assert(!INIT_DONE);
	if (constructor() == null) {
	String types = typeChars;
	CACHE.put(types, this);
	Factory.makeCtors(clazz, types, this.constructor);
	Factory.makeGetters(clazz, types, this.getters);
	Factory.makeNominalGetters(types, this.nominalGetters, this.getters);
	}
	}

	private static final ConcurrentMap<String, SpeciesData> CACHE = new ConcurrentHashMap<>();
	private static final boolean INIT_DONE; // set after <clinit> finishes...

	SpeciesData extendWith(byte type) {
	return extendWith(BasicType.basicType(type));
	}

	SpeciesData extendWith(BasicType type) {
	int ord = type.ordinal();
	SpeciesData d = extensions[ord];
	if (d != null) return d;
	extensions[ord] = d = get(typeChars+type.basicTypeChar());
	return d;
	}

	private static SpeciesData get(String types) {
	return CACHE.computeIfAbsent(types, new Function<String, SpeciesData>() {
	@Override
	public SpeciesData apply(String types) {
	Class<? extends BoundMethodHandle> bmhcl = Factory.getConcreteBMHClass(types);
	// SpeciesData instantiation may throw VirtualMachineError because of
	// code cache overflow...
	SpeciesData speciesData = new SpeciesData(types, bmhcl);
	// CHM.computeIfAbsent ensures only one SpeciesData will be set
	// successfully on the concrete BMH class if ever
	Factory.setSpeciesDataToConcreteBMHClass(bmhcl, speciesData);
	// the concrete BMH class is published via SpeciesData instance
	// returned here only after it's SPECIES_DATA field is set
	return speciesData;
	}
	});
	}

	/**
	* This is to be called when assertions are enabled. It checks whether SpeciesData for all of the statically
	* defined species subclasses of BoundMethodHandle has been added to the SpeciesData cache. See below in the
	* static initializer for
	*/
	static boolean speciesDataCachePopulated() {
	Class<BoundMethodHandle> rootCls = BoundMethodHandle.class;
	try {
	for (Class<?> c : rootCls.getDeclaredClasses()) {
	if (rootCls.isAssignableFrom(c)) {
	final Class<? extends BoundMethodHandle> cbmh = c.asSubclass(BoundMethodHandle.class);
	SpeciesData d = Factory.getSpeciesDataFromConcreteBMHClass(cbmh);
	assert(d != null) : cbmh.getName();
	assert(d.clazz == cbmh);
	assert(CACHE.get(d.typeChars) == d);
	}
	}
	} catch (Throwable e) {
	throw newInternalError(e);
	}
	return true;
	}

	static {
	// Pre-fill the BMH species-data cache with EMPTY and all BMH's inner subclasses.
	EMPTY.initForBootstrap();
	Species_L.SPECIES_DATA.initForBootstrap();
	// check that all static SpeciesData instances have been initialized
	assert speciesDataCachePopulated();
	// Note: Do not simplify this, because INIT_DONE must not be
	// a compile-time constant during bootstrapping.
	INIT_DONE = Boolean.TRUE;
	}
	}

	static SpeciesData getSpeciesData(String types) {
	return SpeciesData.get(types);
	}

	/**
	* Generation of concrete BMH classes.
	*
	* A concrete BMH species is fit for binding a number of values adhering to a
	* given type pattern. Reference types are erased.
	*
	* BMH species are cached by type pattern.
	*
	* A BMH species has a number of fields with the concrete (possibly erased) types of
	* bound values. Setters are provided as an API in BMH. Getters are exposed as MHs,
	* which can be included as names in lambda forms.
	*/
	static class Factory {

	static final String JLO_SIG = "Ljava/lang/Object;";
	static final String JLS_SIG = "Ljava/lang/String;";
	static final String JLC_SIG = "Ljava/lang/Class;";
	static final String MH = "java/lang/invoke/MethodHandle";
	static final String MH_SIG = "L"+MH+";";
	static final String BMH = "java/lang/invoke/BoundMethodHandle";
	static final String BMH_SIG = "L"+BMH+";";
	static final String SPECIES_DATA = "java/lang/invoke/BoundMethodHandle$SpeciesData";
	static final String SPECIES_DATA_SIG = "L"+SPECIES_DATA+";";
	static final String STABLE_SIG = "Ljava/lang/invoke/Stable;";

	static final String SPECIES_PREFIX_NAME = "Species_";
	static final String SPECIES_PREFIX_PATH = BMH + "$" + SPECIES_PREFIX_NAME;

	static final String BMHSPECIES_DATA_EWI_SIG = "(B)" + SPECIES_DATA_SIG;
	static final String BMHSPECIES_DATA_GFC_SIG = "(" + JLS_SIG + JLC_SIG + ")" + SPECIES_DATA_SIG;
	static final String MYSPECIES_DATA_SIG = "()" + SPECIES_DATA_SIG;
	static final String VOID_SIG = "()V";
	static final String INT_SIG = "()I";

	static final String SIG_INCIPIT = "(Ljava/lang/invoke/MethodType;Ljava/lang/invoke/LambdaForm;";

	static final String[] E_THROWABLE = new String[] { "java/lang/Throwable" };

	static final ConcurrentMap<String, Class<? extends BoundMethodHandle>> CLASS_CACHE = new ConcurrentHashMap<>();

	/**
	* Get a concrete subclass of BMH for a given combination of bound types.
	*
	* @param types the type signature, wherein reference types are erased to 'L'
	* @return the concrete BMH class
	*/
	static Class<? extends BoundMethodHandle> getConcreteBMHClass(String types) {
	// CHM.computeIfAbsent ensures generateConcreteBMHClass is called
	// only once per key.
	return CLASS_CACHE.computeIfAbsent(
	types, new Function<String, Class<? extends BoundMethodHandle>>() {
	@Override
	public Class<? extends BoundMethodHandle> apply(String types) {
	return generateConcreteBMHClass(types);
	}
	});
	}

	/**
	* Generate a concrete subclass of BMH for a given combination of bound types.
	*
	* A concrete BMH species adheres to the following schema:
	*
	* <pre>
	* class Species_[[types]] extends BoundMethodHandle {
	* [[fields]]
	* final SpeciesData speciesData() { return SpeciesData.get("[[types]]"); }
	* }
	* </pre>
	*
	* The {@code [[types]]} signature is precisely the string that is passed to this
	* method.
	*
	* The {@code [[fields]]} section consists of one field definition per character in
	* the type signature, adhering to the naming schema described in the definition of
	* {@link #makeFieldName}.
	*
	* For example, a concrete BMH species for two reference and one integral bound values
	* would have the following shape:
	*
	* <pre>
	* class BoundMethodHandle { ... private static
	* final class Species_LLI extends BoundMethodHandle {
	* final Object argL0;
	* final Object argL1;
	* final int argI2;
	* private Species_LLI(MethodType mt, LambdaForm lf, Object argL0, Object argL1, int argI2) {
	* super(mt, lf);
	* this.argL0 = argL0;
	* this.argL1 = argL1;
	* this.argI2 = argI2;
	* }
	* final SpeciesData speciesData() { return SPECIES_DATA; }
	* final int fieldCount() { return 3; }
	* @Stable static SpeciesData SPECIES_DATA; // injected afterwards
	* static BoundMethodHandle make(MethodType mt, LambdaForm lf, Object argL0, Object argL1, int argI2) {
	* return new Species_LLI(mt, lf, argL0, argL1, argI2);
	* }
	* final BoundMethodHandle copyWith(MethodType mt, LambdaForm lf) {
	* return new Species_LLI(mt, lf, argL0, argL1, argI2);
	* }
	* final BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg) {
	* return SPECIES_DATA.extendWith(L_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
	* }
	* final BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg) {
	* return SPECIES_DATA.extendWith(I_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
	* }
	* final BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg) {
	* return SPECIES_DATA.extendWith(J_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
	* }
	* final BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg) {
	* return SPECIES_DATA.extendWith(F_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
	* }
	* public final BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg) {
	* return SPECIES_DATA.extendWith(D_TYPE).constructor().invokeBasic(mt, lf, argL0, argL1, argI2, narg);
	* }
	* }
	* </pre>
	*
	* @param types the type signature, wherein reference types are erased to 'L'
	* @return the generated concrete BMH class
	*/
	static Class<? extends BoundMethodHandle> generateConcreteBMHClass(String types) {
	final ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);

	String shortTypes = LambdaForm.shortenSignature(types);
	final String className = SPECIES_PREFIX_PATH + shortTypes;
	final String sourceFile = SPECIES_PREFIX_NAME + shortTypes;
	final int NOT_ACC_PUBLIC = 0; // not ACC_PUBLIC
	cw.visit(V1_6, NOT_ACC_PUBLIC + ACC_FINAL + ACC_SUPER, className, null, BMH, null);
	cw.visitSource(sourceFile, null);

	// emit static types and SPECIES_DATA fields
	FieldVisitor fw = cw.visitField(NOT_ACC_PUBLIC + ACC_STATIC, "SPECIES_DATA", SPECIES_DATA_SIG, null, null);
	fw.visitAnnotation(STABLE_SIG, true);
	fw.visitEnd();

	// emit bound argument fields
	for (int i = 0; i < types.length(); ++i) {
	final char t = types.charAt(i);
	final String fieldName = makeFieldName(types, i);
	final String fieldDesc = t == 'L' ? JLO_SIG : String.valueOf(t);
	cw.visitField(ACC_FINAL, fieldName, fieldDesc, null, null).visitEnd();
	}

	MethodVisitor mv;

	// emit constructor
	mv = cw.visitMethod(ACC_PRIVATE, "<init>", makeSignature(types, true), null, null);
	mv.visitCode();
	mv.visitVarInsn(ALOAD, 0); // this
	mv.visitVarInsn(ALOAD, 1); // type
	mv.visitVarInsn(ALOAD, 2); // form

	mv.visitMethodInsn(INVOKESPECIAL, BMH, "<init>", makeSignature("", true), false);

	for (int i = 0, j = 0; i < types.length(); ++i, ++j) {
	// i counts the arguments, j counts corresponding argument slots
	char t = types.charAt(i);
	mv.visitVarInsn(ALOAD, 0);
	mv.visitVarInsn(typeLoadOp(t), j + 3); // parameters start at 3
	mv.visitFieldInsn(PUTFIELD, className, makeFieldName(types, i), typeSig(t));
	if (t == 'J' \|\| t == 'D') {
	++j; // adjust argument register access
	}
	}

	mv.visitInsn(RETURN);
	mv.visitMaxs(0, 0);
	mv.visitEnd();

	// emit implementation of speciesData()
	mv = cw.visitMethod(NOT_ACC_PUBLIC + ACC_FINAL, "speciesData", MYSPECIES_DATA_SIG, null, null);
	mv.visitCode();
	mv.visitFieldInsn(GETSTATIC, className, "SPECIES_DATA", SPECIES_DATA_SIG);
	mv.visitInsn(ARETURN);
	mv.visitMaxs(0, 0);
	mv.visitEnd();

	// emit implementation of fieldCount()
	mv = cw.visitMethod(NOT_ACC_PUBLIC + ACC_FINAL, "fieldCount", INT_SIG, null, null);
	mv.visitCode();
	int fc = types.length();
	if (fc <= (ICONST_5 - ICONST_0)) {
	mv.visitInsn(ICONST_0 + fc);
	} else {
	mv.visitIntInsn(SIPUSH, fc);
	}
	mv.visitInsn(IRETURN);
	mv.visitMaxs(0, 0);
	mv.visitEnd();
	// emit make() ...factory method wrapping constructor
	mv = cw.visitMethod(NOT_ACC_PUBLIC + ACC_STATIC, "make", makeSignature(types, false), null, null);
	mv.visitCode();
	// make instance
	mv.visitTypeInsn(NEW, className);
	mv.visitInsn(DUP);
	// load mt, lf
	mv.visitVarInsn(ALOAD, 0); // type
	mv.visitVarInsn(ALOAD, 1); // form
	// load factory method arguments
	for (int i = 0, j = 0; i < types.length(); ++i, ++j) {
	// i counts the arguments, j counts corresponding argument slots
	char t = types.charAt(i);
	mv.visitVarInsn(typeLoadOp(t), j + 2); // parameters start at 3
	if (t == 'J' \|\| t == 'D') {
	++j; // adjust argument register access
	}
	}

	// finally, invoke the constructor and return
	mv.visitMethodInsn(INVOKESPECIAL, className, "<init>", makeSignature(types, true), false);
	mv.visitInsn(ARETURN);
	mv.visitMaxs(0, 0);
	mv.visitEnd();

	// emit copyWith()
	mv = cw.visitMethod(NOT_ACC_PUBLIC + ACC_FINAL, "copyWith", makeSignature("", false), null, null);
	mv.visitCode();
	// make instance
	mv.visitTypeInsn(NEW, className);
	mv.visitInsn(DUP);
	// load mt, lf
	mv.visitVarInsn(ALOAD, 1);
	mv.visitVarInsn(ALOAD, 2);
	// put fields on the stack
	emitPushFields(types, className, mv);
	// finally, invoke the constructor and return
	mv.visitMethodInsn(INVOKESPECIAL, className, "<init>", makeSignature(types, true), false);
	mv.visitInsn(ARETURN);
	mv.visitMaxs(0, 0);
	mv.visitEnd();

	// for each type, emit copyWithExtendT()
	for (BasicType type : BasicType.ARG_TYPES) {
	int ord = type.ordinal();
	char btChar = type.basicTypeChar();
	mv = cw.visitMethod(NOT_ACC_PUBLIC + ACC_FINAL, "copyWithExtend" + btChar, makeSignature(String.valueOf(btChar), false), null, E_THROWABLE);
	mv.visitCode();
	// return SPECIES_DATA.extendWith(t).constructor().invokeBasic(mt, lf, argL0, ..., narg)
	// obtain constructor
	mv.visitFieldInsn(GETSTATIC, className, "SPECIES_DATA", SPECIES_DATA_SIG);
	int iconstInsn = ICONST_0 + ord;
	assert(iconstInsn <= ICONST_5);
	mv.visitInsn(iconstInsn);
	mv.visitMethodInsn(INVOKEVIRTUAL, SPECIES_DATA, "extendWith", BMHSPECIES_DATA_EWI_SIG, false);
	mv.visitMethodInsn(INVOKEVIRTUAL, SPECIES_DATA, "constructor", "()" + MH_SIG, false);
	// load mt, lf
	mv.visitVarInsn(ALOAD, 1);
	mv.visitVarInsn(ALOAD, 2);
	// put fields on the stack
	emitPushFields(types, className, mv);
	// put narg on stack
	mv.visitVarInsn(typeLoadOp(btChar), 3);
	// finally, invoke the constructor and return
	mv.visitMethodInsn(INVOKEVIRTUAL, MH, "invokeBasic", makeSignature(types + btChar, false), false);
	mv.visitInsn(ARETURN);
	mv.visitMaxs(0, 0);
	mv.visitEnd();
	}

	cw.visitEnd();

	// load class
	final byte[] classFile = cw.toByteArray();
	InvokerBytecodeGenerator.maybeDump(className, classFile);
	Class<? extends BoundMethodHandle> bmhClass =
	//UNSAFE.defineAnonymousClass(BoundMethodHandle.class, classFile, null).asSubclass(BoundMethodHandle.class);
	UNSAFE.defineClass(className, classFile, 0, classFile.length,
	BoundMethodHandle.class.getClassLoader(), null)
	.asSubclass(BoundMethodHandle.class);

	return bmhClass;
	}

	private static int typeLoadOp(char t) {
	switch (t) {
	case 'L': return ALOAD;
	case 'I': return ILOAD;
	case 'J': return LLOAD;
	case 'F': return FLOAD;
	case 'D': return DLOAD;
	default : throw newInternalError("unrecognized type " + t);
	}
	}

	private static void emitPushFields(String types, String className, MethodVisitor mv) {
	for (int i = 0; i < types.length(); ++i) {
	char tc = types.charAt(i);
	mv.visitVarInsn(ALOAD, 0);
	mv.visitFieldInsn(GETFIELD, className, makeFieldName(types, i), typeSig(tc));
	}
	}

	static String typeSig(char t) {
	return t == 'L' ? JLO_SIG : String.valueOf(t);
	}

	//
	// Getter MH generation.
	//

	private static MethodHandle makeGetter(Class<?> cbmhClass, String types, int index) {
	String fieldName = makeFieldName(types, index);
	Class<?> fieldType = Wrapper.forBasicType(types.charAt(index)).primitiveType();
	try {
	return LOOKUP.findGetter(cbmhClass, fieldName, fieldType);
	} catch (NoSuchFieldException \| IllegalAccessException e) {
	throw newInternalError(e);
	}
	}

	static MethodHandle[] makeGetters(Class<?> cbmhClass, String types, MethodHandle[] mhs) {
	if (mhs == null) mhs = new MethodHandle[types.length()];
	for (int i = 0; i < mhs.length; ++i) {
	mhs[i] = makeGetter(cbmhClass, types, i);
	assert(mhs[i].internalMemberName().getDeclaringClass() == cbmhClass);
	}
	return mhs;
	}

	static MethodHandle[] makeCtors(Class<? extends BoundMethodHandle> cbmh, String types, MethodHandle mhs[]) {
	if (mhs == null) mhs = new MethodHandle[1];
	if (types.equals("")) return mhs; // hack for empty BMH species
	mhs[0] = makeCbmhCtor(cbmh, types);
	return mhs;
	}

	static NamedFunction[] makeNominalGetters(String types, NamedFunction[] nfs, MethodHandle[] getters) {
	if (nfs == null) nfs = new NamedFunction[types.length()];
	for (int i = 0; i < nfs.length; ++i) {
	nfs[i] = new NamedFunction(getters[i]);
	}
	return nfs;
	}

	//
	// Auxiliary methods.
	//

	static SpeciesData getSpeciesDataFromConcreteBMHClass(Class<? extends BoundMethodHandle> cbmh) {
	try {
	Field F_SPECIES_DATA = cbmh.getDeclaredField("SPECIES_DATA");
	return (SpeciesData) F_SPECIES_DATA.get(null);
	} catch (ReflectiveOperationException ex) {
	throw newInternalError(ex);
	}
	}

	static void setSpeciesDataToConcreteBMHClass(Class<? extends BoundMethodHandle> cbmh, SpeciesData speciesData) {
	try {
	Field F_SPECIES_DATA = cbmh.getDeclaredField("SPECIES_DATA");
	assert F_SPECIES_DATA.getDeclaredAnnotation(Stable.class) != null;
	F_SPECIES_DATA.set(null, speciesData);
	} catch (ReflectiveOperationException ex) {
	throw newInternalError(ex);
	}
	}

	/**
	* Field names in concrete BMHs adhere to this pattern:
	* arg + type + index
	* where type is a single character (L, I, J, F, D).
	*/
	private static String makeFieldName(String types, int index) {
	assert index >= 0 && index < types.length();
	return "arg" + types.charAt(index) + index;
	}

	private static String makeSignature(String types, boolean ctor) {
	StringBuilder buf = new StringBuilder(SIG_INCIPIT);
	for (char c : types.toCharArray()) {
	buf.append(typeSig(c));
	}
	return buf.append(')').append(ctor ? "V" : BMH_SIG).toString();
	}

	static MethodHandle makeCbmhCtor(Class<? extends BoundMethodHandle> cbmh, String types) {
	try {
	return LOOKUP.findStatic(cbmh, "make", MethodType.fromMethodDescriptorString(makeSignature(types, false), null));
	} catch (NoSuchMethodException \| IllegalAccessException \| IllegalArgumentException \| TypeNotPresentException e) {
	throw newInternalError(e);
	}
	}
	}

	private static final Lookup LOOKUP = Lookup.IMPL_LOOKUP;

	/**
	* All subclasses must provide such a value describing their type signature.
	*/
	static final SpeciesData SPECIES_DATA = SpeciesData.EMPTY;

	private static final SpeciesData[] SPECIES_DATA_CACHE = new SpeciesData[5];
	private static SpeciesData checkCache(int size, String types) {
	int idx = size - 1;
	SpeciesData data = SPECIES_DATA_CACHE[idx];
	if (data != null) return data;
	SPECIES_DATA_CACHE[idx] = data = getSpeciesData(types);
	return data;
	}
	static SpeciesData speciesData_L() { return checkCache(1, "L"); }
	static SpeciesData speciesData_LL() { return checkCache(2, "LL"); }
	static SpeciesData speciesData_LLL() { return checkCache(3, "LLL"); }
	static SpeciesData speciesData_LLLL() { return checkCache(4, "LLLL"); }
	static SpeciesData speciesData_LLLLL() { return checkCache(5, "LLLLL"); }
	}

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