1 /*
2 * Copyright (c) 1999, 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.reflect;
27
28 import java.io.IOException;
29 import java.lang.classfile.*;
30 import java.lang.classfile.attribute.ExceptionsAttribute;
31 import java.lang.classfile.constantpool.*;
32 import java.lang.constant.ClassDesc;
33 import java.lang.constant.MethodTypeDesc;
34 import java.nio.file.Files;
35 import java.nio.file.Path;
36 import java.util.ArrayList;
37 import java.util.LinkedHashMap;
38 import java.util.List;
39 import java.util.ListIterator;
40 import java.util.Map;
41 import java.util.Objects;
42
43 import jdk.internal.constant.ClassOrInterfaceDescImpl;
44 import jdk.internal.constant.ConstantUtils;
45 import jdk.internal.constant.MethodTypeDescImpl;
46 import sun.security.action.GetBooleanAction;
47
48 import static java.lang.classfile.ClassFile.*;
49 import java.lang.classfile.attribute.StackMapFrameInfo;
50 import java.lang.classfile.attribute.StackMapTableAttribute;
51
52 import static java.lang.constant.ConstantDescs.*;
53 import static jdk.internal.constant.ConstantUtils.*;
54
55 /**
56 * ProxyGenerator contains the code to generate a dynamic proxy class
57 * for the java.lang.reflect.Proxy API.
58 * <p>
59 * The external interface to ProxyGenerator is the static
60 * "generateProxyClass" method.
61 */
62 final class ProxyGenerator {
63
64 private static final ClassFile CF_CONTEXT =
65 ClassFile.of(ClassFile.StackMapsOption.DROP_STACK_MAPS);
66
67 private static final ClassDesc
68 CD_ClassLoader = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/ClassLoader;"),
69 CD_Class_array = CD_Class.arrayType(),
70 CD_ClassNotFoundException = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/ClassNotFoundException;"),
71 CD_NoClassDefFoundError = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/NoClassDefFoundError;"),
72 CD_IllegalAccessException = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/IllegalAccessException;"),
73 CD_InvocationHandler = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/reflect/InvocationHandler;"),
74 CD_Method = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/reflect/Method;"),
75 CD_NoSuchMethodError = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/NoSuchMethodError;"),
76 CD_NoSuchMethodException = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/NoSuchMethodException;"),
77 CD_Object_array = ConstantUtils.CD_Object_array,
78 CD_Proxy = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/reflect/Proxy;"),
79 CD_UndeclaredThrowableException = ClassOrInterfaceDescImpl.ofValidated("Ljava/lang/reflect/UndeclaredThrowableException;");
80
81 private static final MethodTypeDesc
82 MTD_boolean = MethodTypeDescImpl.ofValidated(CD_boolean),
83 MTD_void_InvocationHandler = MethodTypeDescImpl.ofValidated(CD_void, CD_InvocationHandler),
84 MTD_void_String = MethodTypeDescImpl.ofValidated(CD_void, CD_String),
85 MTD_void_Throwable = MethodTypeDescImpl.ofValidated(CD_void, CD_Throwable),
86 MTD_Class = MethodTypeDescImpl.ofValidated(CD_Class),
87 MTD_Class_String_boolean_ClassLoader = MethodTypeDescImpl.ofValidated(CD_Class, CD_String, CD_boolean, CD_ClassLoader),
88 MTD_ClassLoader = MethodTypeDescImpl.ofValidated(CD_ClassLoader),
89 MTD_Method_String_Class_array = MethodTypeDescImpl.ofValidated(CD_Method, CD_String, CD_Class_array),
90 MTD_MethodHandles$Lookup = MethodTypeDescImpl.ofValidated(CD_MethodHandles_Lookup),
91 MTD_MethodHandles$Lookup_MethodHandles$Lookup = MethodTypeDescImpl.ofValidated(CD_MethodHandles_Lookup, CD_MethodHandles_Lookup),
92 MTD_Object_Object_Method_ObjectArray = MethodTypeDescImpl.ofValidated(CD_Object, CD_Object, CD_Method, CD_Object_array),
93 MTD_String = MethodTypeDescImpl.ofValidated(CD_String);
94
95 private static final String NAME_LOOKUP_ACCESSOR = "proxyClassLookup";
96
97 private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
98
99 /**
100 * name of field for storing a proxy instance's invocation handler
101 */
102 private static final String NAME_HANDLER_FIELD = "h";
103
104 /**
105 * debugging flag for saving generated class files
106 */
107 @SuppressWarnings("removal")
108 private static final boolean SAVE_GENERATED_FILES =
109 java.security.AccessController.doPrivileged(
110 new GetBooleanAction(
111 "jdk.proxy.ProxyGenerator.saveGeneratedFiles"));
112
113 /* Preloaded ProxyMethod objects for methods in java.lang.Object */
114 private static final Method OBJECT_HASH_CODE_METHOD;
115 private static final Method OBJECT_EQUALS_METHOD;
116 private static final Method OBJECT_TO_STRING_METHOD;
117
118 private static final String OBJECT_HASH_CODE_SIG;
119 private static final String OBJECT_EQUALS_SIG;
120 private static final String OBJECT_TO_STRING_SIG;
121
122 static {
123 try {
124 OBJECT_HASH_CODE_METHOD = Object.class.getMethod("hashCode");
125 OBJECT_HASH_CODE_SIG = OBJECT_HASH_CODE_METHOD.toShortSignature();
126 OBJECT_EQUALS_METHOD = Object.class.getMethod("equals", Object.class);
127 OBJECT_EQUALS_SIG = OBJECT_EQUALS_METHOD.toShortSignature();
128 OBJECT_TO_STRING_METHOD = Object.class.getMethod("toString");
129 OBJECT_TO_STRING_SIG = OBJECT_TO_STRING_METHOD.toShortSignature();
130 } catch (NoSuchMethodException e) {
131 throw new NoSuchMethodError(e.getMessage());
132 }
133 }
134
135 private final ConstantPoolBuilder cp;
136 private final List<StackMapFrameInfo.VerificationTypeInfo> classLoaderLocal, throwableStack;
137 private final NameAndTypeEntry exInit;
138 private final ClassEntry objectCE, proxyCE, uteCE, classCE;
139 private final FieldRefEntry handlerField;
140 private final InterfaceMethodRefEntry invocationHandlerInvoke;
141 private final MethodRefEntry uteInit, classGetMethod, classForName, throwableGetMessage;
142
143
144 /**
145 * ClassEntry for this proxy class
146 */
147 private final ClassEntry thisClassCE;
148
149 /**
150 * Proxy interfaces
151 */
152 private final List<Class<?>> interfaces;
153
154 /**
155 * Proxy class access flags
156 */
157 private final int accessFlags;
158
159 /**
160 * Maps method signature string to list of ProxyMethod objects for
161 * proxy methods with that signature.
162 * Kept in insertion order to make it easier to compare old and new.
163 */
164 private final Map<String, List<ProxyMethod>> proxyMethods = new LinkedHashMap<>();
165
166 /**
167 * Ordinal of next ProxyMethod object added to proxyMethods.
168 * Indexes are reserved for hashcode(0), equals(1), toString(2).
169 */
170 private int proxyMethodCount = 3;
171
172 /**
173 * Construct a ProxyGenerator to generate a proxy class with the
174 * specified name and for the given interfaces.
175 * <p>
176 * A ProxyGenerator object contains the state for the ongoing
177 * generation of a particular proxy class.
178 */
179 private ProxyGenerator(String className, List<Class<?>> interfaces,
180 int accessFlags) {
181 this.cp = ConstantPoolBuilder.of();
182 this.thisClassCE = cp.classEntry(ConstantUtils.binaryNameToDesc(className));
183 this.interfaces = interfaces;
184 this.accessFlags = accessFlags;
185 var throwable = cp.classEntry(CD_Throwable);
186 this.classLoaderLocal = List.of(StackMapFrameInfo.ObjectVerificationTypeInfo.of(cp.classEntry(CD_ClassLoader)));
187 this.throwableStack = List.of(StackMapFrameInfo.ObjectVerificationTypeInfo.of(throwable));
188 this.exInit = cp.nameAndTypeEntry(INIT_NAME, MTD_void_String);
189 this.objectCE = cp.classEntry(CD_Object);
190 this.proxyCE = cp.classEntry(CD_Proxy);
191 this.classCE = cp.classEntry(CD_Class);
192 this.handlerField = cp.fieldRefEntry(proxyCE, cp.nameAndTypeEntry(NAME_HANDLER_FIELD, CD_InvocationHandler));
193 this.invocationHandlerInvoke = cp.interfaceMethodRefEntry(CD_InvocationHandler, "invoke", MTD_Object_Object_Method_ObjectArray);
194 this.uteCE = cp.classEntry(CD_UndeclaredThrowableException);
195 this.uteInit = cp.methodRefEntry(uteCE, cp.nameAndTypeEntry(INIT_NAME, MTD_void_Throwable));
196 this.classGetMethod = cp.methodRefEntry(classCE, cp.nameAndTypeEntry("getMethod", MTD_Method_String_Class_array));
197 this.classForName = cp.methodRefEntry(classCE, cp.nameAndTypeEntry("forName", MTD_Class_String_boolean_ClassLoader));
198 this.throwableGetMessage = cp.methodRefEntry(throwable, cp.nameAndTypeEntry("getMessage", MTD_String));
199 }
200
201 /**
202 * Generate a proxy class given a name and a list of proxy interfaces.
203 *
204 * @param name the class name of the proxy class
205 * @param interfaces proxy interfaces
206 * @param accessFlags access flags of the proxy class
207 */
208 @SuppressWarnings("removal")
209 static byte[] generateProxyClass(ClassLoader loader,
210 final String name,
211 List<Class<?>> interfaces,
212 int accessFlags) {
213 Objects.requireNonNull(interfaces);
214 ProxyGenerator gen = new ProxyGenerator(name, interfaces, accessFlags);
215 final byte[] classFile = gen.generateClassFile();
216
217 if (SAVE_GENERATED_FILES) {
218 java.security.AccessController.doPrivileged(
219 new java.security.PrivilegedAction<Void>() {
220 public Void run() {
221 try {
222 int i = name.lastIndexOf('.');
223 Path path;
224 if (i > 0) {
225 Path dir = Path.of(name.substring(0, i).replace('.', '/'));
226 Files.createDirectories(dir);
227 path = dir.resolve(name.substring(i + 1) + ".class");
228 } else {
229 path = Path.of(name + ".class");
230 }
231 Files.write(path, classFile);
232 return null;
233 } catch (IOException e) {
234 throw new InternalError(
235 "I/O exception saving generated file: " + e);
236 }
237 }
238 });
239 }
240
241 return classFile;
242 }
243
244 /**
245 * {@return the entries of the given type}
246 * @param types the {@code Class} objects, not primitive types nor array types
247 */
248 private static List<ClassEntry> toClassEntries(ConstantPoolBuilder cp, List<Class<?>> types) {
249 var ces = new ArrayList<ClassEntry>(types.size());
250 for (var t : types)
251 ces.add(cp.classEntry(ConstantUtils.binaryNameToDesc(t.getName())));
252 return ces;
253 }
254
255 /**
256 * For a given set of proxy methods with the same signature, check
257 * that their return types are compatible according to the Proxy
258 * specification.
259 *
260 * Specifically, if there is more than one such method, then all
261 * of the return types must be reference types, and there must be
262 * one return type that is assignable to each of the rest of them.
263 */
264 private static void checkReturnTypes(List<ProxyMethod> methods) {
265 /*
266 * If there is only one method with a given signature, there
267 * cannot be a conflict. This is the only case in which a
268 * primitive (or void) return type is allowed.
269 */
270 if (methods.size() < 2) {
271 return;
272 }
273
274 /*
275 * List of return types that are not yet known to be
276 * assignable from ("covered" by) any of the others.
277 */
278 List<Class<?>> uncoveredReturnTypes = new ArrayList<>(1);
279
280 nextNewReturnType:
281 for (ProxyMethod pm : methods) {
282 Class<?> newReturnType = pm.returnType;
283 if (newReturnType.isPrimitive()) {
284 throw new IllegalArgumentException(
285 "methods with same signature " +
286 pm.shortSignature +
287 " but incompatible return types: " +
288 newReturnType.getName() + " and others");
289 }
290 boolean added = false;
291
292 /*
293 * Compare the new return type to the existing uncovered
294 * return types.
295 */
296 ListIterator<Class<?>> liter = uncoveredReturnTypes.listIterator();
297 while (liter.hasNext()) {
298 Class<?> uncoveredReturnType = liter.next();
299
300 /*
301 * If an existing uncovered return type is assignable
302 * to this new one, then we can forget the new one.
303 */
304 if (newReturnType.isAssignableFrom(uncoveredReturnType)) {
305 assert !added;
306 continue nextNewReturnType;
307 }
308
309 /*
310 * If the new return type is assignable to an existing
311 * uncovered one, then should replace the existing one
312 * with the new one (or just forget the existing one,
313 * if the new one has already be put in the list).
314 */
315 if (uncoveredReturnType.isAssignableFrom(newReturnType)) {
316 // (we can assume that each return type is unique)
317 if (!added) {
318 liter.set(newReturnType);
319 added = true;
320 } else {
321 liter.remove();
322 }
323 }
324 }
325
326 /*
327 * If we got through the list of existing uncovered return
328 * types without an assignability relationship, then add
329 * the new return type to the list of uncovered ones.
330 */
331 if (!added) {
332 uncoveredReturnTypes.add(newReturnType);
333 }
334 }
335
336 /*
337 * We shouldn't end up with more than one return type that is
338 * not assignable from any of the others.
339 */
340 if (uncoveredReturnTypes.size() > 1) {
341 ProxyMethod pm = methods.getFirst();
342 throw new IllegalArgumentException(
343 "methods with same signature " +
344 pm.shortSignature +
345 " but incompatible return types: " + uncoveredReturnTypes);
346 }
347 }
348
349 /**
350 * Given the exceptions declared in the throws clause of a proxy method,
351 * compute the exceptions that need to be caught from the invocation
352 * handler's invoke method and rethrown intact in the method's
353 * implementation before catching other Throwables and wrapping them
354 * in UndeclaredThrowableExceptions.
355 *
356 * The exceptions to be caught are returned in a List object. Each
357 * exception in the returned list is guaranteed to not be a subclass of
358 * any of the other exceptions in the list, so the catch blocks for
359 * these exceptions may be generated in any order relative to each other.
360 *
361 * Error and RuntimeException are each always contained by the returned
362 * list (if none of their superclasses are contained), since those
363 * unchecked exceptions should always be rethrown intact, and thus their
364 * subclasses will never appear in the returned list.
365 *
366 * The returned List will be empty if java.lang.Throwable is in the
367 * given list of declared exceptions, indicating that no exceptions
368 * need to be caught.
369 */
370 private static List<Class<?>> computeUniqueCatchList(Class<?>[] exceptions) {
371 List<Class<?>> uniqueList = new ArrayList<>();
372 // unique exceptions to catch
373
374 uniqueList.add(Error.class); // always catch/rethrow these
375 uniqueList.add(RuntimeException.class);
376
377 nextException:
378 for (Class<?> ex : exceptions) {
379 if (ex.isAssignableFrom(Throwable.class)) {
380 /*
381 * If Throwable is declared to be thrown by the proxy method,
382 * then no catch blocks are necessary, because the invoke
383 * can, at most, throw Throwable anyway.
384 */
385 uniqueList.clear();
386 break;
387 } else if (!Throwable.class.isAssignableFrom(ex)) {
388 /*
389 * Ignore types that cannot be thrown by the invoke method.
390 */
391 continue;
392 }
393 /*
394 * Compare this exception against the current list of
395 * exceptions that need to be caught:
396 */
397 for (int j = 0; j < uniqueList.size(); ) {
398 Class<?> ex2 = uniqueList.get(j);
399 if (ex2.isAssignableFrom(ex)) {
400 /*
401 * if a superclass of this exception is already on
402 * the list to catch, then ignore this one and continue;
403 */
404 continue nextException;
405 } else if (ex.isAssignableFrom(ex2)) {
406 /*
407 * if a subclass of this exception is on the list
408 * to catch, then remove it;
409 */
410 uniqueList.remove(j);
411 } else {
412 j++; // else continue comparing.
413 }
414 }
415 // This exception is unique (so far): add it to the list to catch.
416 uniqueList.add(ex);
417 }
418 return uniqueList;
419 }
420
421 /**
422 * Add to the given list all of the types in the "from" array that
423 * are not already contained in the list and are assignable to at
424 * least one of the types in the "with" array.
425 * <p>
426 * This method is useful for computing the greatest common set of
427 * declared exceptions from duplicate methods inherited from
428 * different interfaces.
429 */
430 private static void collectCompatibleTypes(Class<?>[] from,
431 Class<?>[] with,
432 List<Class<?>> list) {
433 for (Class<?> fc : from) {
434 if (!list.contains(fc)) {
435 for (Class<?> wc : with) {
436 if (wc.isAssignableFrom(fc)) {
437 list.add(fc);
438 break;
439 }
440 }
441 }
442 }
443 }
444
445 /**
446 * Generate a class file for the proxy class. This method drives the
447 * class file generation process.
448 */
449 private byte[] generateClassFile() {
450 /*
451 * Add proxy methods for the hashCode, equals,
452 * and toString methods of java.lang.Object. This is done before
453 * the methods from the proxy interfaces so that the methods from
454 * java.lang.Object take precedence over duplicate methods in the
455 * proxy interfaces.
456 */
457 addProxyMethod(new ProxyMethod(OBJECT_HASH_CODE_METHOD, OBJECT_HASH_CODE_SIG, "m0"));
458 addProxyMethod(new ProxyMethod(OBJECT_EQUALS_METHOD, OBJECT_EQUALS_SIG, "m1"));
459 addProxyMethod(new ProxyMethod(OBJECT_TO_STRING_METHOD, OBJECT_TO_STRING_SIG, "m2"));
460
461 /*
462 * Accumulate all of the methods from the proxy interfaces.
463 */
464 for (Class<?> intf : interfaces) {
465 for (Method m : intf.getMethods()) {
466 if (!Modifier.isStatic(m.getModifiers())) {
467 addProxyMethod(m, intf);
468 }
469 }
470 }
471
472 /*
473 * For each set of proxy methods with the same signature,
474 * verify that the methods' return types are compatible.
475 */
476 for (List<ProxyMethod> sigmethods : proxyMethods.values()) {
477 checkReturnTypes(sigmethods);
478 }
479
480 return CF_CONTEXT.build(thisClassCE, cp, clb -> {
481 clb.withSuperclass(proxyCE);
482 clb.withFlags(accessFlags);
483 clb.withInterfaces(toClassEntries(cp, interfaces));
484 generateConstructor(clb);
485
486 for (List<ProxyMethod> sigmethods : proxyMethods.values()) {
487 for (ProxyMethod pm : sigmethods) {
488 // add static field for the Method object
489 clb.withField(pm.methodFieldName, CD_Method, ACC_PRIVATE | ACC_STATIC | ACC_FINAL);
490
491 // Generate code for proxy method
492 pm.generateMethod(clb);
493 }
494 }
495
496 generateStaticInitializer(clb);
497 generateLookupAccessor(clb);
498 });
499 }
500
501 /**
502 * Add another method to be proxied, either by creating a new
503 * ProxyMethod object or augmenting an old one for a duplicate
504 * method.
505 *
506 * "fromClass" indicates the proxy interface that the method was
507 * found through, which may be different from (a subinterface of)
508 * the method's "declaring class". Note that the first Method
509 * object passed for a given name and descriptor identifies the
510 * Method object (and thus the declaring class) that will be
511 * passed to the invocation handler's "invoke" method for a given
512 * set of duplicate methods.
513 */
514 private void addProxyMethod(Method m, Class<?> fromClass) {
515 Class<?> returnType = m.getReturnType();
516 Class<?>[] exceptionTypes = m.getSharedExceptionTypes();
517
518 String sig = m.toShortSignature();
519 List<ProxyMethod> sigmethods = proxyMethodsFor(sig);
520 for (ProxyMethod pm : sigmethods) {
521 if (returnType == pm.returnType) {
522 /*
523 * Found a match: reduce exception types to the
524 * greatest set of exceptions that can be thrown
525 * compatibly with the throws clauses of both
526 * overridden methods.
527 */
528 List<Class<?>> legalExceptions = new ArrayList<>();
529 collectCompatibleTypes(
530 exceptionTypes, pm.exceptionTypes, legalExceptions);
531 collectCompatibleTypes(
532 pm.exceptionTypes, exceptionTypes, legalExceptions);
533 pm.exceptionTypes = legalExceptions.toArray(EMPTY_CLASS_ARRAY);
534 return;
535 }
536 }
537 sigmethods.add(new ProxyMethod(m, sig, returnType,
538 exceptionTypes, fromClass, "m" + proxyMethodCount++));
539 }
540
541 private List<ProxyMethod> proxyMethodsFor(String sig) {
542 return proxyMethods.computeIfAbsent(sig, _ -> new ArrayList<>(3));
543 }
544
545 /**
546 * Add an existing ProxyMethod (hashcode, equals, toString).
547 *
548 * @param pm an existing ProxyMethod
549 */
550 private void addProxyMethod(ProxyMethod pm) {
551 proxyMethodsFor(pm.shortSignature).add(pm);
552 }
553
554 /**
555 * Generate the constructor method for the proxy class.
556 */
557 private void generateConstructor(ClassBuilder clb) {
558 clb.withMethodBody(INIT_NAME, MTD_void_InvocationHandler, ACC_PUBLIC, cob -> cob
559 .aload(0)
560 .aload(1)
561 .invokespecial(cp.methodRefEntry(proxyCE,
562 cp.nameAndTypeEntry(INIT_NAME, MTD_void_InvocationHandler)))
563 .return_());
564 }
565
566 /**
567 * Generate the class initializer.
568 * Discussion: Currently, for Proxy to work with SecurityManager,
569 * we rely on the parameter classes of the methods to be computed
570 * from Proxy instead of via user code paths like bootstrap method
571 * lazy evaluation. That might change if we can pass in the live
572 * Method objects directly..
573 */
574 private void generateStaticInitializer(ClassBuilder clb) {
575 clb.withMethodBody(CLASS_INIT_NAME, MTD_void, ACC_STATIC, cob -> {
576 // Put ClassLoader at local variable index 0, used by
577 // Class.forName(String, boolean, ClassLoader) calls
578 cob.ldc(thisClassCE)
579 .invokevirtual(cp.methodRefEntry(classCE,
580 cp.nameAndTypeEntry("getClassLoader", MTD_ClassLoader)))
581 .astore(0);
582 var ts = cob.newBoundLabel();
583 for (List<ProxyMethod> sigmethods : proxyMethods.values()) {
584 for (ProxyMethod pm : sigmethods) {
585 pm.codeFieldInitialization(cob);
586 }
587 }
588 cob.return_();
589 var c1 = cob.newBoundLabel();
590 var nsmError = cp.classEntry(CD_NoSuchMethodError);
591 cob.exceptionCatch(ts, c1, c1, CD_NoSuchMethodException)
592 .new_(nsmError)
593 .dup_x1()
594 .swap()
595 .invokevirtual(throwableGetMessage)
596 .invokespecial(cp.methodRefEntry(nsmError, exInit))
597 .athrow();
598 var c2 = cob.newBoundLabel();
599 var ncdfError = cp.classEntry(CD_NoClassDefFoundError);
600 cob.exceptionCatch(ts, c1, c2, CD_ClassNotFoundException)
601 .new_(ncdfError)
602 .dup_x1()
603 .swap()
604 .invokevirtual(throwableGetMessage)
605 .invokespecial(cp.methodRefEntry(ncdfError, exInit))
606 .athrow();
607 cob.with(StackMapTableAttribute.of(List.of(
608 StackMapFrameInfo.of(c1, classLoaderLocal, throwableStack),
609 StackMapFrameInfo.of(c2, classLoaderLocal, throwableStack))));
610
611 });
612 }
613
614 /**
615 * Generate the static lookup accessor method that returns the Lookup
616 * on this proxy class if the caller's lookup class is java.lang.reflect.Proxy;
617 * otherwise, IllegalAccessException is thrown
618 */
619 private void generateLookupAccessor(ClassBuilder clb) {
620 clb.withMethod(NAME_LOOKUP_ACCESSOR,
621 MTD_MethodHandles$Lookup_MethodHandles$Lookup,
622 ACC_PRIVATE | ACC_STATIC,
623 mb -> mb.with(ExceptionsAttribute.of(List.of(mb.constantPool().classEntry(CD_IllegalAccessException))))
624 .withCode(cob -> {
625 Label failLabel = cob.newLabel();
626 ClassEntry mhl = cp.classEntry(CD_MethodHandles_Lookup);
627 ClassEntry iae = cp.classEntry(CD_IllegalAccessException);
628 cob.aload(0)
629 .invokevirtual(cp.methodRefEntry(mhl, cp.nameAndTypeEntry("lookupClass", MTD_Class)))
630 .ldc(proxyCE)
631 .if_acmpne(failLabel)
632 .aload(0)
633 .invokevirtual(cp.methodRefEntry(mhl, cp.nameAndTypeEntry("hasFullPrivilegeAccess", MTD_boolean)))
634 .ifeq(failLabel)
635 .invokestatic(CD_MethodHandles, "lookup", MTD_MethodHandles$Lookup)
636 .areturn()
637 .labelBinding(failLabel)
638 .new_(iae)
639 .dup()
640 .aload(0)
641 .invokevirtual(cp.methodRefEntry(mhl, cp.nameAndTypeEntry("toString", MTD_String)))
642 .invokespecial(cp.methodRefEntry(iae, exInit))
643 .athrow()
644 .with(StackMapTableAttribute.of(List.of(
645 StackMapFrameInfo.of(failLabel,
646 List.of(StackMapFrameInfo.ObjectVerificationTypeInfo.of(mhl)),
647 List.of()))));
648 }));
649 }
650
651 /**
652 * A ProxyMethod object represents a proxy method in the proxy class
653 * being generated: a method whose implementation will encode and
654 * dispatch invocations to the proxy instance's invocation handler.
655 */
656 private class ProxyMethod {
657
658 private final Method method;
659 private final String shortSignature;
660 private final Class<?> fromClass;
661 private final Class<?> returnType;
662 private final String methodFieldName;
663 private Class<?>[] exceptionTypes;
664 private final FieldRefEntry methodField;
665
666 private ProxyMethod(Method method, String sig,
667 Class<?> returnType, Class<?>[] exceptionTypes,
668 Class<?> fromClass, String methodFieldName) {
669 this.method = method;
670 this.shortSignature = sig;
671 this.returnType = returnType;
672 this.exceptionTypes = exceptionTypes;
673 this.fromClass = fromClass;
674 this.methodFieldName = methodFieldName;
675 this.methodField = cp.fieldRefEntry(thisClassCE,
676 cp.nameAndTypeEntry(methodFieldName, CD_Method));
677 }
678
679 private Class<?>[] parameterTypes() {
680 return method.getSharedParameterTypes();
681 }
682
683 /**
684 * Create a new specific ProxyMethod with a specific field name
685 *
686 * @param method The method for which to create a proxy
687 */
688 private ProxyMethod(Method method, String sig, String methodFieldName) {
689 this(method, sig, method.getReturnType(),
690 method.getSharedExceptionTypes(), method.getDeclaringClass(), methodFieldName);
691 }
692
693 /**
694 * Generate this method, including the code and exception table entry.
695 */
696 private void generateMethod(ClassBuilder clb) {
697 var desc = methodTypeDesc(returnType, parameterTypes());
698 int accessFlags = (method.isVarArgs()) ? ACC_VARARGS | ACC_PUBLIC | ACC_FINAL
699 : ACC_PUBLIC | ACC_FINAL;
700 clb.withMethod(method.getName(), desc, accessFlags, mb ->
701 mb.with(ExceptionsAttribute.of(toClassEntries(cp, List.of(exceptionTypes))))
702 .withCode(cob -> {
703 var catchList = computeUniqueCatchList(exceptionTypes);
704 cob.aload(cob.receiverSlot())
705 .getfield(handlerField)
706 .aload(cob.receiverSlot())
707 .getstatic(methodField);
708 Class<?>[] parameterTypes = parameterTypes();
709 if (parameterTypes.length > 0) {
710 // Create an array and fill with the parameters converting primitives to wrappers
711 cob.loadConstant(parameterTypes.length)
712 .anewarray(objectCE);
713 for (int i = 0; i < parameterTypes.length; i++) {
714 cob.dup()
715 .loadConstant(i);
716 codeWrapArgument(cob, parameterTypes[i], cob.parameterSlot(i));
717 cob.aastore();
718 }
719 } else {
720 cob.aconst_null();
721 }
722
723 cob.invokeinterface(invocationHandlerInvoke);
724
725 if (returnType == void.class) {
726 cob.pop()
727 .return_();
728 } else {
729 codeUnwrapReturnValue(cob, returnType);
730 }
731 if (!catchList.isEmpty()) {
732 var c1 = cob.newBoundLabel();
733 for (var exc : catchList) {
734 cob.exceptionCatch(cob.startLabel(), c1, c1, referenceClassDesc(exc));
735 }
736 cob.athrow(); // just rethrow the exception
737 var c2 = cob.newBoundLabel();
738 cob.exceptionCatchAll(cob.startLabel(), c1, c2)
739 .new_(uteCE)
740 .dup_x1()
741 .swap()
742 .invokespecial(uteInit)
743 .athrow()
744 .with(StackMapTableAttribute.of(List.of(
745 StackMapFrameInfo.of(c1, List.of(), throwableStack),
746 StackMapFrameInfo.of(c2, List.of(), throwableStack))));
747 }
748 }));
749 }
750
751 /**
752 * Generate code for wrapping an argument of the given type
753 * whose value can be found at the specified local variable
754 * index, in order for it to be passed (as an Object) to the
755 * invocation handler's "invoke" method.
756 */
757 private void codeWrapArgument(CodeBuilder cob, Class<?> type, int slot) {
758 if (type.isPrimitive()) {
759 cob.loadLocal(TypeKind.from(type).asLoadable(), slot);
760 PrimitiveTypeInfo prim = PrimitiveTypeInfo.get(type);
761 cob.invokestatic(prim.wrapperMethodRef(cp));
762 } else {
763 cob.aload(slot);
764 }
765 }
766
767 /**
768 * Generate code for unwrapping a return value of the given
769 * type from the invocation handler's "invoke" method (as type
770 * Object) to its correct type.
771 */
772 private void codeUnwrapReturnValue(CodeBuilder cob, Class<?> type) {
773 if (type.isPrimitive()) {
774 PrimitiveTypeInfo prim = PrimitiveTypeInfo.get(type);
775
776 cob.checkcast(prim.wrapperClass)
777 .invokevirtual(prim.unwrapMethodRef(cp))
778 .return_(TypeKind.from(type).asLoadable());
779 } else {
780 cob.checkcast(referenceClassDesc(type))
781 .areturn();
782 }
783 }
784
785 /**
786 * Generate code for initializing the static field that stores
787 * the Method object for this proxy method. A class loader is
788 * anticipated at local variable index 0.
789 * The generated code must be run in an AccessController.doPrivileged
790 * block if a SecurityManager is present, as otherwise the code
791 * cannot pass {@code null} ClassLoader to forName.
792 */
793 private void codeFieldInitialization(CodeBuilder cob) {
794 var cp = cob.constantPool();
795 codeClassForName(cob, fromClass);
796
797 Class<?>[] parameterTypes = parameterTypes();
798 cob.ldc(method.getName())
799 .loadConstant(parameterTypes.length)
800 .anewarray(classCE);
801
802 // Construct an array with the parameter types mapping primitives to Wrapper types
803 for (int i = 0; i < parameterTypes.length; i++) {
804 cob.dup()
805 .loadConstant(i);
806 if (parameterTypes[i].isPrimitive()) {
807 PrimitiveTypeInfo prim = PrimitiveTypeInfo.get(parameterTypes[i]);
808 cob.getstatic(prim.typeFieldRef(cp));
809 } else {
810 codeClassForName(cob, parameterTypes[i]);
811 }
812 cob.aastore();
813 }
814 // lookup the method
815 cob.invokevirtual(classGetMethod)
816 .putstatic(methodField);
817 }
818
819 /*
820 * =============== Code Generation Utility Methods ===============
821 */
822
823 /**
824 * Generate code to invoke the Class.forName with the name of the given
825 * class to get its Class object at runtime. The code is written to
826 * the supplied stream. Note that the code generated by this method
827 * may cause the checked ClassNotFoundException to be thrown. A class
828 * loader is anticipated at local variable index 0.
829 */
830 private void codeClassForName(CodeBuilder cob, Class<?> cl) {
831 if (cl == Object.class) {
832 cob.ldc(objectCE);
833 } else {
834 cob.ldc(cl.getName())
835 .iconst_0() // false
836 .aload(0)// classLoader
837 .invokestatic(classForName);
838 }
839 }
840
841 @Override
842 public String toString() {
843 return method.toShortString();
844 }
845 }
846
847 /**
848 * A PrimitiveTypeInfo object contains bytecode-related information about
849 * a primitive type in its instance fields. The struct for a particular
850 * primitive type can be obtained using the static "get" method.
851 */
852 private enum PrimitiveTypeInfo {
853 BYTE(byte.class, CD_byte, CD_Byte),
854 CHAR(char.class, CD_char, CD_Character),
855 DOUBLE(double.class, CD_double, CD_Double),
856 FLOAT(float.class, CD_float, CD_Float),
857 INT(int.class, CD_int, CD_Integer),
858 LONG(long.class, CD_long, CD_Long),
859 SHORT(short.class, CD_short, CD_Short),
860 BOOLEAN(boolean.class, CD_boolean, CD_Boolean);
861
862 /**
863 * wrapper class
864 */
865 private final ClassDesc wrapperClass;
866 /**
867 * wrapper factory method type
868 */
869 private final MethodTypeDesc wrapperMethodType;
870 /**
871 * wrapper class method name for retrieving primitive value
872 */
873 private final String unwrapMethodName;
874 /**
875 * wrapper class method type for retrieving primitive value
876 */
877 private final MethodTypeDesc unwrapMethodType;
878
879 PrimitiveTypeInfo(Class<?> primitiveClass, ClassDesc baseType, ClassDesc wrapperClass) {
880 assert baseType.isPrimitive();
881 this.wrapperClass = wrapperClass;
882 this.wrapperMethodType = MethodTypeDescImpl.ofValidated(wrapperClass, baseType);
883 this.unwrapMethodName = primitiveClass.getName() + "Value";
884 this.unwrapMethodType = MethodTypeDescImpl.ofValidated(baseType);
885 }
886
887 public static PrimitiveTypeInfo get(Class<?> cl) {
888 // Uses if chain for speed: 8284880
889 if (cl == int.class) return INT;
890 if (cl == long.class) return LONG;
891 if (cl == boolean.class) return BOOLEAN;
892 if (cl == short.class) return SHORT;
893 if (cl == byte.class) return BYTE;
894 if (cl == char.class) return CHAR;
895 if (cl == float.class) return FLOAT;
896 if (cl == double.class) return DOUBLE;
897 throw new AssertionError(cl);
898 }
899
900 public MethodRefEntry wrapperMethodRef(ConstantPoolBuilder cp) {
901 return cp.methodRefEntry(wrapperClass, "valueOf", wrapperMethodType);
902 }
903
904 public MethodRefEntry unwrapMethodRef(ConstantPoolBuilder cp) {
905 return cp.methodRefEntry(wrapperClass, unwrapMethodName, unwrapMethodType);
906 }
907
908 public FieldRefEntry typeFieldRef(ConstantPoolBuilder cp) {
909 return cp.fieldRefEntry(wrapperClass, "TYPE", CD_Class);
910 }
911 }
912 }