1 /*
  2  * Copyright (c) 2012, 2024, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.  Oracle designates this
  8  * particular file as subject to the "Classpath" exception as provided
  9  * by Oracle in the LICENSE file that accompanied this code.
 10  *
 11  * This code is distributed in the hope that it will be useful, but WITHOUT
 12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 14  * version 2 for more details (a copy is included in the LICENSE file that
 15  * accompanied this code).
 16  *
 17  * You should have received a copy of the GNU General Public License version
 18  * 2 along with this work; if not, write to the Free Software Foundation,
 19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 20  *
 21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 22  * or visit www.oracle.com if you need additional information or have any
 23  * questions.
 24  */
 25 
 26 package java.lang.invoke;
 27 
 28 import jdk.internal.access.JavaLangInvokeAccess.ReflectableLambdaInfo;
 29 import jdk.internal.constant.ClassOrInterfaceDescImpl;
 30 import jdk.internal.misc.CDS;
 31 import jdk.internal.util.ClassFileDumper;
 32 import sun.invoke.util.VerifyAccess;
 33 
 34 import java.io.Serializable;
 35 import java.lang.classfile.ClassBuilder;
 36 import java.lang.classfile.ClassFile;
 37 import java.lang.classfile.CodeBuilder;
 38 import java.lang.classfile.MethodBuilder;
 39 import java.lang.classfile.Opcode;
 40 import java.lang.classfile.TypeKind;
 41 import java.lang.classfile.constantpool.MethodHandleEntry;
 42 import java.lang.classfile.constantpool.NameAndTypeEntry;
 43 import java.lang.constant.ClassDesc;
 44 import java.lang.constant.MethodTypeDesc;
 45 import java.lang.reflect.Modifier;
 46 import java.util.LinkedHashSet;
 47 import java.util.List;
 48 import java.util.Set;
 49 import java.util.function.Consumer;
 50 
 51 import static java.lang.classfile.ClassFile.*;
 52 import java.lang.classfile.attribute.ExceptionsAttribute;
 53 import java.lang.classfile.constantpool.ClassEntry;
 54 import java.lang.classfile.constantpool.ConstantPoolBuilder;
 55 
 56 import static java.lang.constant.ConstantDescs.*;
 57 import static java.lang.invoke.MethodHandleNatives.Constants.NESTMATE_CLASS;
 58 import static java.lang.invoke.MethodHandleNatives.Constants.STRONG_LOADER_LINK;
 59 import jdk.internal.constant.ConstantUtils;
 60 import jdk.internal.constant.MethodTypeDescImpl;
 61 import jdk.internal.vm.annotation.Stable;
 62 import sun.invoke.util.Wrapper;
 63 
 64 /**
 65  * Lambda metafactory implementation which dynamically creates an
 66  * inner-class-like class per lambda callsite.
 67  *
 68  * @see LambdaMetafactory
 69  */
 70 /* package */ final class InnerClassLambdaMetafactory extends AbstractValidatingLambdaMetafactory {
 71     private static final String LAMBDA_INSTANCE_FIELD = "LAMBDA_INSTANCE$";
 72     private static final @Stable String[] ARG_NAME_CACHE = {"arg$1", "arg$2", "arg$3", "arg$4", "arg$5", "arg$6", "arg$7", "arg$8"};
 73     private static final ClassDesc[] EMPTY_CLASSDESC_ARRAY = ConstantUtils.EMPTY_CLASSDESC;
 74 
 75     // Static builders to avoid lambdas
 76     record MethodBody(Consumer<CodeBuilder> code) implements Consumer<MethodBuilder> {
 77         @Override
 78         public void accept(MethodBuilder mb) {
 79             mb.withCode(code);
 80         }
 81     };
 82 
 83     // For dumping generated classes to disk, for debugging purposes
 84     private static final ClassFileDumper lambdaProxyClassFileDumper;
 85 
 86     private static final boolean disableEagerInitialization;
 87 
 88     private static final String NAME_METHOD_QUOTED = "__internal_quoted";
 89     private static final String quotedInstanceFieldName = "quoted";
 90     private static final String COMPILER_GENERATED_MODEL_FIELD_NAME = "COMPILER_GENERATED_MODEL";
 91 
 92     static {
 93         // To dump the lambda proxy classes, set this system property:
 94         //    -Djdk.invoke.LambdaMetafactory.dumpProxyClassFiles
 95         // or -Djdk.invoke.LambdaMetafactory.dumpProxyClassFiles=true
 96         final String dumpProxyClassesKey = "jdk.invoke.LambdaMetafactory.dumpProxyClassFiles";
 97         lambdaProxyClassFileDumper = ClassFileDumper.getInstance(dumpProxyClassesKey, "DUMP_LAMBDA_PROXY_CLASS_FILES");
 98 
 99         final String disableEagerInitializationKey = "jdk.internal.lambda.disableEagerInitialization";
100         disableEagerInitialization = Boolean.getBoolean(disableEagerInitializationKey);
101     }
102 
103     // See context values in AbstractValidatingLambdaMetafactory
104     private final ClassDesc implMethodClassDesc;     // Name of type containing implementation "CC"
105     private final String implMethodName;             // Name of implementation method "impl"
106     private final MethodTypeDesc implMethodDesc;     // Type descriptor for implementation methods "(I)Ljava/lang/String;"
107     private final MethodType constructorType;        // Generated class constructor type "(CC)void"
108     private final MethodTypeDesc constructorTypeDesc;// Type descriptor for the generated class constructor type "(CC)void"
109     private final ClassDesc[] argDescs;              // Type descriptors for the constructor arguments
110     private final String lambdaClassName;            // Generated name for the generated class "X$$Lambda$1"
111     private final ConstantPoolBuilder pool = ConstantPoolBuilder.of();
112     private final ClassEntry lambdaClassEntry;       // Class entry for the generated class "X$$Lambda$1"
113     private final boolean useImplMethodHandle;       // use MethodHandle invocation instead of symbolic bytecode invocation
114 
115     /**
116      * General meta-factory constructor, supporting both standard cases and
117      * allowing for uncommon options such as serialization or bridging.
118      *
119      * @param caller Stacked automatically by VM; represents a lookup context
120      *               with the accessibility privileges of the caller.
121      * @param factoryType Stacked automatically by VM; the signature of the
122      *                    invoked method, which includes the expected static
123      *                    type of the returned lambda object, and the static
124      *                    types of the captured arguments for the lambda.  In
125      *                    the event that the implementation method is an
126      *                    instance method, the first argument in the invocation
127      *                    signature will correspond to the receiver.
128      * @param interfaceMethodName Name of the method in the functional interface to
129      *                   which the lambda or method reference is being
130      *                   converted, represented as a String.
131      * @param interfaceMethodType Type of the method in the functional interface to
132      *                            which the lambda or method reference is being
133      *                            converted, represented as a MethodType.
134      * @param implementation The implementation method which should be called (with
135      *                       suitable adaptation of argument types, return types,
136      *                       and adjustment for captured arguments) when methods of
137      *                       the resulting functional interface instance are invoked.
138      * @param dynamicMethodType The signature of the primary functional
139      *                          interface method after type variables are
140      *                          substituted with their instantiation from
141      *                          the capture site
142      * @param isSerializable Should the lambda be made serializable?  If set,
143      *                       either the target type or one of the additional SAM
144      *                       types must extend {@code Serializable}.
145      * @param altInterfaces Additional interfaces which the lambda object
146      *                      should implement.
147      * @param altMethods Method types for additional signatures to be
148      *                   implemented by invoking the implementation method
149      * @throws LambdaConversionException If any of the meta-factory protocol
150      *         invariants are violated
151      */
152     public InnerClassLambdaMetafactory(MethodHandles.Lookup caller,
153                                        MethodType factoryType,
154                                        String interfaceMethodName,
155                                        MethodType interfaceMethodType,
156                                        MethodHandle implementation,
157                                        MethodType dynamicMethodType,
158                                        boolean isSerializable,
159                                        Class<?>[] altInterfaces,
160                                        MethodType[] altMethods,
161                                        ReflectableLambdaInfo reflectableLambdaInfo)
162             throws LambdaConversionException {
163         super(caller, factoryType, interfaceMethodName, interfaceMethodType,
164               implementation, dynamicMethodType,
165               isSerializable, altInterfaces, altMethods, reflectableLambdaInfo);
166         implMethodClassDesc = implClassDesc(implClass);
167         implMethodName = implInfo.getName();
168         implMethodDesc = methodDesc(implInfo.getMethodType());
169         constructorType = factoryType.changeReturnType(Void.TYPE);
170         lambdaClassName = lambdaClassName(targetClass);
171         lambdaClassEntry = pool.classEntry(ConstantUtils.internalNameToDesc(lambdaClassName));
172         // If the target class invokes a protected method inherited from a
173         // superclass in a different package, or does 'invokespecial', the
174         // lambda class has no access to the resolved method, or does
175         // 'invokestatic' on a hidden class which cannot be resolved by name.
176         // Instead, we need to pass the live implementation method handle to
177         // the proxy class to invoke directly. (javac prefers to avoid this
178         // situation by generating bridges in the target class)
179         useImplMethodHandle = (Modifier.isProtected(implInfo.getModifiers()) &&
180                                !VerifyAccess.isSamePackage(targetClass, implInfo.getDeclaringClass())) ||
181                                implKind == MethodHandleInfo.REF_invokeSpecial ||
182                                implKind == MethodHandleInfo.REF_invokeStatic && implClass.isHidden();
183         int parameterCount = factoryType.parameterCount();
184         ClassDesc[] argDescs;
185         MethodTypeDesc constructorTypeDesc;
186         if (parameterCount > 0) {
187             argDescs = new ClassDesc[parameterCount];
188             for (int i = 0; i < parameterCount; i++) {
189                 argDescs[i] = classDesc(factoryType.parameterType(i));
190             }
191             constructorTypeDesc = MethodTypeDescImpl.ofValidated(CD_void, argDescs);
192         } else {
193             argDescs = EMPTY_CLASSDESC_ARRAY;
194             constructorTypeDesc = MTD_void;
195         }
196         this.argDescs = argDescs;
197         this.constructorTypeDesc = constructorTypeDesc;
198     }
199 
200     private static String argName(int i) {
201         return i < ARG_NAME_CACHE.length ? ARG_NAME_CACHE[i] :  "arg$" + (i + 1);
202     }
203 
204     private static String sanitizedTargetClassName(Class<?> targetClass) {
205         String name = targetClass.getName();
206         if (targetClass.isHidden()) {
207             // use the original class name
208             name = name.replace('/', '_');
209         }
210         return name.replace('.', '/');
211     }
212 
213     private static String lambdaClassName(Class<?> targetClass) {
214         return sanitizedTargetClassName(targetClass).concat("$$Lambda");
215     }
216 
217     /**
218      * Build the CallSite. Generate a class file which implements the functional
219      * interface, define the class, if there are no parameters create an instance
220      * of the class which the CallSite will return, otherwise, generate handles
221      * which will call the class' constructor.
222      *
223      * @return a CallSite, which, when invoked, will return an instance of the
224      * functional interface
225      * @throws LambdaConversionException If properly formed functional interface
226      * is not found
227      */
228     @Override
229     CallSite buildCallSite() throws LambdaConversionException {
230         final Class<?> innerClass = spinInnerClass();
231         if (factoryType.parameterCount() == 0 && disableEagerInitialization) {
232             try {
233                 return new ConstantCallSite(caller.findStaticGetter(innerClass, LAMBDA_INSTANCE_FIELD,
234                                                                     factoryType.returnType()));
235             } catch (ReflectiveOperationException e) {
236                 throw new LambdaConversionException(
237                         "Exception finding " + LAMBDA_INSTANCE_FIELD + " static field", e);
238             }
239         } else {
240             try {
241                 MethodHandle mh = caller.findConstructor(innerClass, constructorType);
242                 if (factoryType.parameterCount() == 0) {
243                     // In the case of a non-capturing lambda, we optimize linkage by pre-computing a single instance
244                     Object inst = mh.invokeBasic();
245                     return new ConstantCallSite(MethodHandles.constant(interfaceClass, inst));
246                 } else {
247                     return new ConstantCallSite(mh.asType(factoryType));
248                 }
249             } catch (ReflectiveOperationException e) {
250                 throw new LambdaConversionException("Exception finding constructor", e);
251             } catch (Throwable e) {
252                 throw new LambdaConversionException("Exception instantiating lambda object", e);
253             }
254         }
255     }
256 
257     /**
258      * Spins the lambda proxy class.
259      *
260      * This first checks if a lambda proxy class can be loaded from CDS archive.
261      * Otherwise, generate the lambda proxy class. If CDS dumping is enabled, it
262      * registers the lambda proxy class for including into the CDS archive.
263      */
264     private Class<?> spinInnerClass() throws LambdaConversionException {
265         // CDS does not handle disableEagerInitialization or useImplMethodHandle
266         if (!disableEagerInitialization && !useImplMethodHandle) {
267             if (CDS.isUsingArchive()) {
268                 // load from CDS archive if present
269                 Class<?> innerClass = LambdaProxyClassArchive.find(targetClass,
270                                                                    interfaceMethodName,
271                                                                    factoryType,
272                                                                    interfaceMethodType,
273                                                                    implementation,
274                                                                    dynamicMethodType,
275                                                                    isSerializable,
276                                                                    altInterfaces,
277                                                                    altMethods);
278                 if (innerClass != null) return innerClass;
279             }
280 
281             // include lambda proxy class in CDS archive at dump time
282             if (CDS.isDumpingArchive()) {
283                 Class<?> innerClass = generateInnerClass();
284                 LambdaProxyClassArchive.register(targetClass,
285                                                  interfaceMethodName,
286                                                  factoryType,
287                                                  interfaceMethodType,
288                                                  implementation,
289                                                  dynamicMethodType,
290                                                  isSerializable,
291                                                  altInterfaces,
292                                                  altMethods,
293                                                  innerClass);
294                 return innerClass;
295             }
296 
297         }
298         return generateInnerClass();
299     }
300 
301     /**
302      * Generate a class file which implements the functional
303      * interface, define and return the class.
304      *
305      * @return a Class which implements the functional interface
306      * @throws LambdaConversionException If properly formed functional interface
307      * is not found
308      */
309     private Class<?> generateInnerClass() throws LambdaConversionException {
310         List<ClassDesc> interfaces;
311         ClassDesc interfaceDesc = classDesc(interfaceClass);
312         boolean accidentallySerializable = !isSerializable && Serializable.class.isAssignableFrom(interfaceClass);
313         if (altInterfaces.length == 0) {
314             interfaces = List.of(interfaceDesc);
315         } else {
316             // Assure no duplicate interfaces (ClassFormatError)
317             Set<ClassDesc> itfs = LinkedHashSet.newLinkedHashSet(altInterfaces.length + 1);
318             itfs.add(interfaceDesc);
319             for (Class<?> i : altInterfaces) {
320                 itfs.add(classDesc(i));
321                 accidentallySerializable |= !isSerializable && Serializable.class.isAssignableFrom(i);
322             }
323             interfaces = List.copyOf(itfs);
324         }
325         final boolean finalAccidentallySerializable = accidentallySerializable;
326         final byte[] classBytes = ClassFile.of().build(lambdaClassEntry, pool, new Consumer<ClassBuilder>() {
327             @Override
328             public void accept(ClassBuilder clb) {
329                 clb.withFlags(ACC_SUPER | ACC_FINAL | ACC_SYNTHETIC)
330                    .withInterfaceSymbols(interfaces);
331                 // Generate final fields to be filled in by constructor
332                 for (int i = 0; i < argDescs.length; i++) {
333                     clb.withField(argName(i), argDescs[i], ACC_PRIVATE | ACC_FINAL);
334                 }
335 
336                 // if quotable, generate the field that will hold the value of quoted
337                 if (reflectableLambdaInfo != null) {
338                     clb.withField(quotedInstanceFieldName, reflectableLambdaInfo.quotedClass(), ACC_PRIVATE + ACC_FINAL);
339                 }
340 
341                 generateConstructor(clb);
342 
343                 generateClassInitializationMethod(clb);
344 
345 
346                 // Forward the SAM method
347                 clb.withMethodBody(interfaceMethodName,
348                         methodDesc(interfaceMethodType),
349                         ACC_PUBLIC,
350                         forwardingMethod(interfaceMethodType));
351 
352                 // Forward the bridges
353                 if (altMethods != null) {
354                     for (MethodType mt : altMethods) {
355                         clb.withMethodBody(interfaceMethodName,
356                                 methodDesc(mt),
357                                 ACC_PUBLIC | ACC_BRIDGE,
358                                 forwardingMethod(mt));
359                     }
360                 }
361 
362                 if (isSerializable)
363                     generateSerializationFriendlyMethods(clb);
364                 else if (finalAccidentallySerializable)
365                     generateSerializationHostileMethods(clb);
366 
367                 if (reflectableLambdaInfo != null) {
368                     generateQuotedMethod(clb);
369                 }
370             }
371         });
372 
373         // Define the generated class in this VM.
374 
375         try {
376             // this class is linked at the indy callsite; so define a hidden nestmate
377             List<?> classdata;
378             if (useImplMethodHandle || reflectableLambdaInfo != null) {
379                 classdata = reflectableLambdaInfo == null ?
380                         List.of(implementation) :
381                         List.of(implementation, reflectableLambdaInfo.opHandle(), reflectableLambdaInfo.extractOpHandle());
382             } else {
383                 classdata = null;
384             }
385             return caller.makeHiddenClassDefiner(lambdaClassName, classBytes, lambdaProxyClassFileDumper, NESTMATE_CLASS | STRONG_LOADER_LINK)
386                          .defineClass(!disableEagerInitialization, classdata);
387 
388         } catch (Throwable t) {
389             throw new InternalError(t);
390         }
391     }
392 
393     private void generateClassInitializationMethod(ClassBuilder clb) {
394         if (!(factoryType.parameterCount() == 0 && disableEagerInitialization) && reflectableLambdaInfo == null) {
395             return;
396         }
397         clb.withMethodBody(CLASS_INIT_NAME, MTD_void, ACC_STATIC, new Consumer<CodeBuilder>() {
398             @Override
399             public void accept(CodeBuilder cob) {
400                 if (factoryType.parameterCount() == 0 && disableEagerInitialization) {
401                     ClassDesc lambdaTypeDescriptor = classDesc(factoryType.returnType());
402                     // Generate the static final field that holds the lambda singleton
403                     clb.withField(LAMBDA_INSTANCE_FIELD, lambdaTypeDescriptor, ACC_PRIVATE | ACC_STATIC | ACC_FINAL);
404                     cob.new_(lambdaClassEntry)
405                             .dup()
406                             .invokespecial(pool.methodRefEntry(lambdaClassEntry, pool.nameAndTypeEntry(INIT_NAME, constructorTypeDesc)))
407                             .putstatic(pool.fieldRefEntry(lambdaClassEntry, pool.nameAndTypeEntry(LAMBDA_INSTANCE_FIELD, lambdaTypeDescriptor)));
408                 }
409 
410                 if (reflectableLambdaInfo != null) {
411                     // if we visit a callsite twice, we will use the same class
412                     // if the lambda doesn't capture values we only have one instance, model shared anyway
413                     // if it captures values, each visit result in a creation of new instance of the class
414                     // those instances have the same code model generated by the compiler
415                     // they may differ in captured values
416                     // as first step let's share the compiler generated code model
417                     ClassDesc funcOpClassDesc = reflectableLambdaInfo.funcOpClass();
418                     clb.withField(COMPILER_GENERATED_MODEL_FIELD_NAME, funcOpClassDesc,
419                             ACC_PRIVATE | ACC_STATIC | ACC_FINAL);
420 
421                     ConstantPoolBuilder cp = pool;
422                     MethodHandleEntry bsmDataAt = cp.methodHandleEntry(BSM_CLASS_DATA_AT);
423                     NameAndTypeEntry natMH = cp.nameAndTypeEntry(DEFAULT_NAME, CD_MethodHandle);
424                     // load quotableOpGetter
425                     cob.ldc(cp.constantDynamicEntry(cp.bsmEntry(bsmDataAt, List.of(cp.intEntry(1))), natMH));
426                     MethodType mtype = quotableOpGetterInfo.getMethodType();
427                     if (quotableOpGetterInfo.getReferenceKind() != MethodHandleInfo.REF_invokeStatic) {
428                         mtype = mtype.insertParameterTypes(0, implClass);
429                     }
430                     cob.invokevirtual(CD_MethodHandle, "invokeExact", mtype.describeConstable().get());
431                     cob.checkcast(funcOpClassDesc);
432                     cob.putstatic(lambdaClassEntry.asSymbol(), COMPILER_GENERATED_MODEL_FIELD_NAME, funcOpClassDesc);
433                 }
434                 cob.return_();
435             }
436         });
437     }
438 
439     /**
440      * Generate the constructor for the class
441      */
442     private void generateConstructor(ClassBuilder clb) {
443         // Generate constructor
444         clb.withMethodBody(INIT_NAME, constructorTypeDesc, ACC_PRIVATE,
445                 new Consumer<>() {
446                     @Override
447                     public void accept(CodeBuilder cob) {
448                         cob.aload(0)
449                            .invokespecial(CD_Object, INIT_NAME, MTD_void);
450                         int parameterCount = factoryType.parameterCount();
451                         for (int i = 0; i < parameterCount; i++) {
452                             cob.aload(0)
453                                .loadLocal(TypeKind.from(factoryType.parameterType(i)), cob.parameterSlot(i))
454                                .putfield(pool.fieldRefEntry(lambdaClassEntry, pool.nameAndTypeEntry(argName(i), argDescs[i])));
455                         }
456                         if (reflectableLambdaInfo != null) {
457                             generateQuotedFieldInitializer(cob);
458                         }
459                         cob.return_();
460                     }
461                 });
462     }
463 
464     private void generateQuotedFieldInitializer(CodeBuilder cob) {
465         ConstantPoolBuilder cp = cob.constantPool();
466         MethodHandleEntry bsmDataAt = cp.methodHandleEntry(BSM_CLASS_DATA_AT);
467         NameAndTypeEntry natMH = cp.nameAndTypeEntry(DEFAULT_NAME, CD_MethodHandle);
468         // push the receiver on the stack for operand of put field instruction
469         cob.aload(0)
470                 // load class data: CodeReflectionSupport.HANDLE_MAKE_QUOTED
471                 .ldc(cp.constantDynamicEntry(cp.bsmEntry(bsmDataAt, List.of(cp.intEntry(2))), natMH))
472                 .getstatic(lambdaClassEntry.asSymbol(), COMPILER_GENERATED_MODEL_FIELD_NAME,
473                         reflectableLambdaInfo.funcOpClass());
474 
475 
476         // load captured args in array
477 
478         int capturedArity = factoryType.parameterCount();
479         cob.loadConstant(capturedArity)
480            .anewarray(CD_Object);
481         // initialize quoted captures
482         for (int i = 0; i < capturedArity; i++) {
483             cob.dup()
484                .loadConstant(i)
485                .aload(0)
486                .getfield(lambdaClassEntry.asSymbol(), argName(i), argDescs[i]);
487             TypeConvertingMethodAdapter.boxIfTypePrimitive(cob, TypeKind.from(argDescs[i]));
488             cob.aastore();
489         }
490 
491         // Create a Quoted from FuncOp and captured args Object[]
492 
493         cob.invokevirtual(CD_MethodHandle, "invokeExact", methodDesc(reflectableLambdaInfo.extractOpHandle().type()))
494            .putfield(lambdaClassEntry.asSymbol(), quotedInstanceFieldName, reflectableLambdaInfo.quotedClass());
495     }
496 
497     private static class SerializationSupport {
498         // Serialization support
499         private static final ClassDesc CD_SerializedLambda = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/invoke/SerializedLambda;");
500         private static final ClassDesc CD_ObjectOutputStream = ClassOrInterfaceDescImpl.ofValidated("Ljava/io/ObjectOutputStream;");
501         private static final ClassDesc CD_ObjectInputStream = ClassOrInterfaceDescImpl.ofValidated("Ljava/io/ObjectInputStream;");
502         private static final MethodTypeDesc MTD_Object = MethodTypeDescImpl.ofValidated(CD_Object);
503         private static final MethodTypeDesc MTD_void_ObjectOutputStream = MethodTypeDescImpl.ofValidated(CD_void, CD_ObjectOutputStream);
504         private static final MethodTypeDesc MTD_void_ObjectInputStream = MethodTypeDescImpl.ofValidated(CD_void, CD_ObjectInputStream);
505 
506         private static final String NAME_METHOD_WRITE_REPLACE = "writeReplace";
507         private static final String NAME_METHOD_READ_OBJECT = "readObject";
508         private static final String NAME_METHOD_WRITE_OBJECT = "writeObject";
509 
510         static final ClassDesc CD_NotSerializableException = ClassOrInterfaceDescImpl.ofValidated("Ljava/io/NotSerializableException;");
511         static final MethodTypeDesc MTD_CTOR_NOT_SERIALIZABLE_EXCEPTION = MethodTypeDescImpl.ofValidated(CD_void, CD_String);
512         static final MethodTypeDesc MTD_CTOR_SERIALIZED_LAMBDA = MethodTypeDescImpl.ofValidated(CD_void,
513                 CD_Class, CD_String, CD_String, CD_String, CD_int, CD_String, CD_String, CD_String, CD_String, ConstantUtils.CD_Object_array);
514 
515     }
516 
517     /**
518      * Generate a writeReplace method that supports serialization
519      */
520     private void generateSerializationFriendlyMethods(ClassBuilder clb) {
521         clb.withMethodBody(SerializationSupport.NAME_METHOD_WRITE_REPLACE, SerializationSupport.MTD_Object, ACC_PRIVATE | ACC_FINAL,
522                 new Consumer<>() {
523                     @Override
524                     public void accept(CodeBuilder cob) {
525                         cob.new_(SerializationSupport.CD_SerializedLambda)
526                            .dup()
527                            .ldc(ClassDesc.ofInternalName(sanitizedTargetClassName(targetClass)))
528                            .ldc(factoryType.returnType().getName().replace('.', '/'))
529                            .ldc(interfaceMethodName)
530                            .ldc(interfaceMethodType.toMethodDescriptorString())
531                            .ldc(implInfo.getReferenceKind())
532                            .ldc(implInfo.getDeclaringClass().getName().replace('.', '/'))
533                            .ldc(implInfo.getName())
534                            .ldc(implInfo.getMethodType().toMethodDescriptorString())
535                            .ldc(dynamicMethodType.toMethodDescriptorString())
536                            .loadConstant(argDescs.length)
537                            .anewarray(CD_Object);
538                         for (int i = 0; i < argDescs.length; i++) {
539                             cob.dup()
540                                .loadConstant(i)
541                                .aload(0)
542                                .getfield(pool.fieldRefEntry(lambdaClassEntry, pool.nameAndTypeEntry(argName(i), argDescs[i])));
543                             TypeConvertingMethodAdapter.boxIfTypePrimitive(cob, TypeKind.from(argDescs[i]));
544                             cob.aastore();
545                         }
546                         cob.invokespecial(SerializationSupport.CD_SerializedLambda, INIT_NAME,
547                                           SerializationSupport.MTD_CTOR_SERIALIZED_LAMBDA)
548                            .areturn();
549                     }
550                 });
551     }
552 
553     /**
554     * Generate method #quoted()
555      */
556     private void generateQuotedMethod(ClassBuilder clb) {
557         clb.withMethod(NAME_METHOD_QUOTED, MethodTypeDesc.of(reflectableLambdaInfo.quotedClass()), ACC_PRIVATE + ACC_FINAL, new MethodBody(new Consumer<CodeBuilder>() {
558             @Override
559             public void accept(CodeBuilder cob) {
560                 cob.aload(0)
561                    .getfield(lambdaClassEntry.asSymbol(), quotedInstanceFieldName, reflectableLambdaInfo.quotedClass())
562                    .areturn();
563             }
564         }));
565     }
566 
567     /**
568      * Generate a readObject/writeObject method that is hostile to serialization
569      */
570     private void generateSerializationHostileMethods(ClassBuilder clb) {
571         var hostileMethod = new Consumer<MethodBuilder>() {
572             @Override
573             public void accept(MethodBuilder mb) {
574                 ConstantPoolBuilder cp = mb.constantPool();
575                 ClassEntry nseCE = cp.classEntry(SerializationSupport.CD_NotSerializableException);
576                 mb.with(ExceptionsAttribute.of(nseCE))
577                         .withCode(new Consumer<CodeBuilder>() {
578                             @Override
579                             public void accept(CodeBuilder cob) {
580                                 cob.new_(nseCE)
581                                         .dup()
582                                         .ldc("Non-serializable lambda")
583                                         .invokespecial(cp.methodRefEntry(nseCE, cp.nameAndTypeEntry(INIT_NAME,
584                                                 SerializationSupport.MTD_CTOR_NOT_SERIALIZABLE_EXCEPTION)))
585                                         .athrow();
586                             }
587                         });
588             }
589         };
590         clb.withMethod(SerializationSupport.NAME_METHOD_WRITE_OBJECT, SerializationSupport.MTD_void_ObjectOutputStream,
591                 ACC_PRIVATE + ACC_FINAL, hostileMethod);
592         clb.withMethod(SerializationSupport.NAME_METHOD_READ_OBJECT, SerializationSupport.MTD_void_ObjectInputStream,
593                 ACC_PRIVATE + ACC_FINAL, hostileMethod);
594     }
595 
596     /**
597      * This method generates a method body which calls the lambda implementation
598      * method, converting arguments, as needed.
599      */
600     Consumer<CodeBuilder> forwardingMethod(MethodType methodType) {
601         return new Consumer<>() {
602             @Override
603             public void accept(CodeBuilder cob) {
604                 if (implKind == MethodHandleInfo.REF_newInvokeSpecial) {
605                     cob.new_(implMethodClassDesc)
606                        .dup();
607                 }
608                 if (useImplMethodHandle) {
609                     ConstantPoolBuilder cp = cob.constantPool();
610                     cob.ldc(cp.constantDynamicEntry(cp.bsmEntry(cp.methodHandleEntry(BSM_CLASS_DATA_AT), List.of(cp.intEntry(0))),
611                                                     cp.nameAndTypeEntry(DEFAULT_NAME, CD_MethodHandle)));
612                 }
613                 for (int i = 0; i < argDescs.length; i++) {
614                     cob.aload(0)
615                        .getfield(pool.fieldRefEntry(lambdaClassEntry, pool.nameAndTypeEntry(argName(i), argDescs[i])));
616                 }
617 
618                 convertArgumentTypes(cob, methodType);
619 
620                 if (useImplMethodHandle) {
621                     MethodType mtype = implInfo.getMethodType();
622                     if (implKind != MethodHandleInfo.REF_invokeStatic) {
623                         mtype = mtype.insertParameterTypes(0, implClass);
624                     }
625                     cob.invokevirtual(CD_MethodHandle, "invokeExact", methodDesc(mtype));
626                 } else {
627                     // Invoke the method we want to forward to
628                     cob.invoke(invocationOpcode(), implMethodClassDesc, implMethodName, implMethodDesc, implClass.isInterface());
629                 }
630                 // Convert the return value (if any) and return it
631                 // Note: if adapting from non-void to void, the 'return'
632                 // instruction will pop the unneeded result
633                 Class<?> implReturnClass = implMethodType.returnType();
634                 Class<?> samReturnClass = methodType.returnType();
635                 TypeConvertingMethodAdapter.convertType(cob, implReturnClass, samReturnClass, samReturnClass);
636                 cob.return_(TypeKind.from(samReturnClass));
637             }
638         };
639     }
640 
641     private void convertArgumentTypes(CodeBuilder cob, MethodType samType) {
642         int samParametersLength = samType.parameterCount();
643         int captureArity = factoryType.parameterCount();
644         for (int i = 0; i < samParametersLength; i++) {
645             Class<?> argType = samType.parameterType(i);
646             cob.loadLocal(TypeKind.from(argType), cob.parameterSlot(i));
647             TypeConvertingMethodAdapter.convertType(cob, argType, implMethodType.parameterType(captureArity + i), dynamicMethodType.parameterType(i));
648         }
649     }
650 
651     private Opcode invocationOpcode() throws InternalError {
652         return switch (implKind) {
653             case MethodHandleInfo.REF_invokeStatic     -> Opcode.INVOKESTATIC;
654             case MethodHandleInfo.REF_newInvokeSpecial -> Opcode.INVOKESPECIAL;
655             case MethodHandleInfo.REF_invokeVirtual    -> Opcode.INVOKEVIRTUAL;
656             case MethodHandleInfo.REF_invokeInterface  -> Opcode.INVOKEINTERFACE;
657             case MethodHandleInfo.REF_invokeSpecial    -> Opcode.INVOKESPECIAL;
658             default -> throw new InternalError("Unexpected invocation kind: " + implKind);
659         };
660     }
661 
662     static ClassDesc implClassDesc(Class<?> cls) {
663         return cls.isHidden() ? null : ConstantUtils.referenceClassDesc(cls.descriptorString());
664     }
665 
666     static ClassDesc classDesc(Class<?> cls) {
667         return cls.isPrimitive() ? Wrapper.forPrimitiveType(cls).basicClassDescriptor()
668                                  : ConstantUtils.referenceClassDesc(cls.descriptorString());
669     }
670 
671     static MethodTypeDesc methodDesc(MethodType mt) {
672         var params = new ClassDesc[mt.parameterCount()];
673         for (int i = 0; i < params.length; i++) {
674             params[i] = classDesc(mt.parameterType(i));
675         }
676         return MethodTypeDescImpl.ofValidated(classDesc(mt.returnType()), params);
677     }
678 }