1 /*
2 * Copyright (c) 2008, 2018, 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.ref.CleanerFactory;
29 import sun.invoke.util.Wrapper;
30
31 import java.lang.invoke.MethodHandles.Lookup;
32 import java.lang.reflect.Field;
33
34 import static java.lang.invoke.MethodHandleNatives.Constants.*;
35 import static java.lang.invoke.MethodHandleStatics.TRACE_METHOD_LINKAGE;
36 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
37
38 /**
39 * The JVM interface for the method handles package is all here.
40 * This is an interface internal and private to an implementation of JSR 292.
41 * <em>This class is not part of the JSR 292 standard.</em>
42 * @author jrose
43 */
44 class MethodHandleNatives {
45
46 private MethodHandleNatives() { } // static only
47
48 /// MemberName support
49
50 static native void init(MemberName self, Object ref);
51 static native void expand(MemberName self);
52 static native MemberName resolve(MemberName self, Class<?> caller,
53 boolean speculativeResolve) throws LinkageError, ClassNotFoundException;
54 static native int getMembers(Class<?> defc, String matchName, String matchSig,
55 int matchFlags, Class<?> caller, int skip, MemberName[] results);
56
57 /// Field layout queries parallel to jdk.internal.misc.Unsafe:
58 static native long objectFieldOffset(MemberName self); // e.g., returns vmindex
59 static native long staticFieldOffset(MemberName self); // e.g., returns vmindex
60 static native Object staticFieldBase(MemberName self); // e.g., returns clazz
61 static native Object getMemberVMInfo(MemberName self); // returns {vmindex,vmtarget}
62
63 /// CallSite support
64
65 /** Tell the JVM that we need to change the target of a CallSite. */
66 static native void setCallSiteTargetNormal(CallSite site, MethodHandle target);
67 static native void setCallSiteTargetVolatile(CallSite site, MethodHandle target);
68
69 static native void copyOutBootstrapArguments(Class<?> caller, int[] indexInfo,
70 int start, int end,
71 Object[] buf, int pos,
72 boolean resolve,
73 Object ifNotAvailable);
74
75 /** Represents a context to track nmethod dependencies on CallSite instance target. */
76 static class CallSiteContext implements Runnable {
77 //@Injected JVM_nmethodBucket* vmdependencies;
78 //@Injected jlong last_cleanup;
79
80 static CallSiteContext make(CallSite cs) {
81 final CallSiteContext newContext = new CallSiteContext();
82 // CallSite instance is tracked by a Cleanable which clears native
83 // structures allocated for CallSite context. Though the CallSite can
84 // become unreachable, its Context is retained by the Cleanable instance
85 // (which is referenced from Cleaner instance which is referenced from
86 // CleanerFactory class) until cleanup is performed.
87 CleanerFactory.cleaner().register(cs, newContext);
88 return newContext;
89 }
90
91 @Override
92 public void run() {
93 MethodHandleNatives.clearCallSiteContext(this);
94 }
95 }
96
97 /** Invalidate all recorded nmethods. */
98 private static native void clearCallSiteContext(CallSiteContext context);
99
100 private static native void registerNatives();
101 static {
102 registerNatives();
103 }
104
105 /**
106 * Compile-time constants go here. This collection exists not only for
107 * reference from clients, but also for ensuring the VM and JDK agree on the
108 * values of these constants (see {@link #verifyConstants()}).
109 */
110 static class Constants {
111 Constants() { } // static only
112
113 static final int
114 MN_IS_METHOD = 0x00010000, // method (not constructor)
115 MN_IS_CONSTRUCTOR = 0x00020000, // constructor
116 MN_IS_FIELD = 0x00040000, // field
117 MN_IS_TYPE = 0x00080000, // nested type
118 MN_CALLER_SENSITIVE = 0x00100000, // @CallerSensitive annotation detected
119 MN_REFERENCE_KIND_SHIFT = 24, // refKind
120 MN_REFERENCE_KIND_MASK = 0x0F000000 >> MN_REFERENCE_KIND_SHIFT,
121 // The SEARCH_* bits are not for MN.flags but for the matchFlags argument of MHN.getMembers:
122 MN_SEARCH_SUPERCLASSES = 0x00100000,
123 MN_SEARCH_INTERFACES = 0x00200000;
124
125 /**
126 * Constant pool reference-kind codes, as used by CONSTANT_MethodHandle CP entries.
127 */
128 static final byte
129 REF_NONE = 0, // null value
130 REF_getField = 1,
131 REF_getStatic = 2,
132 REF_putField = 3,
133 REF_putStatic = 4,
134 REF_invokeVirtual = 5,
135 REF_invokeStatic = 6,
136 REF_invokeSpecial = 7,
137 REF_newInvokeSpecial = 8,
138 REF_invokeInterface = 9,
139 REF_LIMIT = 10;
140 }
141
142 static boolean refKindIsValid(int refKind) {
143 return (refKind > REF_NONE && refKind < REF_LIMIT);
144 }
145 static boolean refKindIsField(byte refKind) {
146 assert(refKindIsValid(refKind));
147 return (refKind <= REF_putStatic);
148 }
149 static boolean refKindIsGetter(byte refKind) {
150 assert(refKindIsValid(refKind));
151 return (refKind <= REF_getStatic);
152 }
153 static boolean refKindIsSetter(byte refKind) {
154 return refKindIsField(refKind) && !refKindIsGetter(refKind);
155 }
156 static boolean refKindIsMethod(byte refKind) {
157 return !refKindIsField(refKind) && (refKind != REF_newInvokeSpecial);
158 }
159 static boolean refKindIsConstructor(byte refKind) {
160 return (refKind == REF_newInvokeSpecial);
161 }
162 static boolean refKindHasReceiver(byte refKind) {
163 assert(refKindIsValid(refKind));
164 return (refKind & 1) != 0;
165 }
166 static boolean refKindIsStatic(byte refKind) {
167 return !refKindHasReceiver(refKind) && (refKind != REF_newInvokeSpecial);
168 }
169 static boolean refKindDoesDispatch(byte refKind) {
170 assert(refKindIsValid(refKind));
171 return (refKind == REF_invokeVirtual ||
172 refKind == REF_invokeInterface);
173 }
174 static {
175 final int HR_MASK = ((1 << REF_getField) |
176 (1 << REF_putField) |
177 (1 << REF_invokeVirtual) |
178 (1 << REF_invokeSpecial) |
179 (1 << REF_invokeInterface)
180 );
181 for (byte refKind = REF_NONE+1; refKind < REF_LIMIT; refKind++) {
182 assert(refKindHasReceiver(refKind) == (((1<<refKind) & HR_MASK) != 0)) : refKind;
183 }
184 }
185 static String refKindName(byte refKind) {
186 assert(refKindIsValid(refKind));
187 switch (refKind) {
188 case REF_getField: return "getField";
189 case REF_getStatic: return "getStatic";
190 case REF_putField: return "putField";
191 case REF_putStatic: return "putStatic";
192 case REF_invokeVirtual: return "invokeVirtual";
193 case REF_invokeStatic: return "invokeStatic";
194 case REF_invokeSpecial: return "invokeSpecial";
195 case REF_newInvokeSpecial: return "newInvokeSpecial";
196 case REF_invokeInterface: return "invokeInterface";
197 default: return "REF_???";
198 }
199 }
200
201 private static native int getNamedCon(int which, Object[] name);
202 static boolean verifyConstants() {
203 Object[] box = { null };
204 for (int i = 0; ; i++) {
205 box[0] = null;
206 int vmval = getNamedCon(i, box);
207 if (box[0] == null) break;
208 String name = (String) box[0];
209 try {
210 Field con = Constants.class.getDeclaredField(name);
211 int jval = con.getInt(null);
212 if (jval == vmval) continue;
213 String err = (name+": JVM has "+vmval+" while Java has "+jval);
214 if (name.equals("CONV_OP_LIMIT")) {
215 System.err.println("warning: "+err);
216 continue;
217 }
218 throw new InternalError(err);
219 } catch (NoSuchFieldException | IllegalAccessException ex) {
220 String err = (name+": JVM has "+vmval+" which Java does not define");
221 // ignore exotic ops the JVM cares about; we just wont issue them
222 //System.err.println("warning: "+err);
223 continue;
224 }
225 }
226 return true;
227 }
228 static {
229 assert(verifyConstants());
230 }
231
232 // Up-calls from the JVM.
233 // These must NOT be public.
234
235 /**
236 * The JVM is linking an invokedynamic instruction. Create a reified call site for it.
237 */
238 static MemberName linkCallSite(Object callerObj,
239 int indexInCP,
240 Object bootstrapMethodObj,
241 Object nameObj, Object typeObj,
242 Object staticArguments,
243 Object[] appendixResult) {
244 MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj;
245 Class<?> caller = (Class<?>)callerObj;
246 String name = nameObj.toString().intern();
247 MethodType type = (MethodType)typeObj;
248 if (!TRACE_METHOD_LINKAGE)
249 return linkCallSiteImpl(caller, bootstrapMethod, name, type,
250 staticArguments, appendixResult);
251 return linkCallSiteTracing(caller, bootstrapMethod, name, type,
252 staticArguments, appendixResult);
253 }
254 static MemberName linkCallSiteImpl(Class<?> caller,
255 MethodHandle bootstrapMethod,
256 String name, MethodType type,
257 Object staticArguments,
258 Object[] appendixResult) {
259 CallSite callSite = CallSite.makeSite(bootstrapMethod,
260 name,
261 type,
262 staticArguments,
263 caller);
264 if (callSite instanceof ConstantCallSite) {
265 appendixResult[0] = callSite.dynamicInvoker();
266 return Invokers.linkToTargetMethod(type);
267 } else {
268 appendixResult[0] = callSite;
269 return Invokers.linkToCallSiteMethod(type);
270 }
271 }
272 // Tracing logic:
273 static MemberName linkCallSiteTracing(Class<?> caller,
274 MethodHandle bootstrapMethod,
275 String name, MethodType type,
276 Object staticArguments,
277 Object[] appendixResult) {
278 Object bsmReference = bootstrapMethod.internalMemberName();
279 if (bsmReference == null) bsmReference = bootstrapMethod;
280 String staticArglist = staticArglistForTrace(staticArguments);
281 System.out.println("linkCallSite "+caller.getName()+" "+
282 bsmReference+" "+
283 name+type+"/"+staticArglist);
284 try {
285 MemberName res = linkCallSiteImpl(caller, bootstrapMethod, name, type,
286 staticArguments, appendixResult);
287 System.out.println("linkCallSite => "+res+" + "+appendixResult[0]);
288 return res;
289 } catch (Throwable ex) {
290 ex.printStackTrace(); // print now in case exception is swallowed
291 System.out.println("linkCallSite => throw "+ex);
292 throw ex;
293 }
294 }
295
296 // this implements the upcall from the JVM, MethodHandleNatives.linkDynamicConstant:
297 static Object linkDynamicConstant(Object callerObj,
298 int indexInCP,
299 Object bootstrapMethodObj,
300 Object nameObj, Object typeObj,
301 Object staticArguments) {
302 MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj;
303 Class<?> caller = (Class<?>)callerObj;
304 String name = nameObj.toString().intern();
305 Class<?> type = (Class<?>)typeObj;
306 if (!TRACE_METHOD_LINKAGE)
307 return linkDynamicConstantImpl(caller, bootstrapMethod, name, type, staticArguments);
308 return linkDynamicConstantTracing(caller, bootstrapMethod, name, type, staticArguments);
309 }
310
311 static Object linkDynamicConstantImpl(Class<?> caller,
312 MethodHandle bootstrapMethod,
313 String name, Class<?> type,
314 Object staticArguments) {
315 return ConstantBootstraps.makeConstant(bootstrapMethod, name, type, staticArguments, caller);
316 }
317
318 private static String staticArglistForTrace(Object staticArguments) {
319 if (staticArguments instanceof Object[])
320 return "BSA="+java.util.Arrays.asList((Object[]) staticArguments);
321 if (staticArguments instanceof int[])
322 return "BSA@"+java.util.Arrays.toString((int[]) staticArguments);
323 if (staticArguments == null)
324 return "BSA0=null";
325 return "BSA1="+staticArguments;
326 }
327
328 // Tracing logic:
329 static Object linkDynamicConstantTracing(Class<?> caller,
330 MethodHandle bootstrapMethod,
331 String name, Class<?> type,
332 Object staticArguments) {
333 Object bsmReference = bootstrapMethod.internalMemberName();
334 if (bsmReference == null) bsmReference = bootstrapMethod;
335 String staticArglist = staticArglistForTrace(staticArguments);
336 System.out.println("linkDynamicConstant "+caller.getName()+" "+
337 bsmReference+" "+
338 name+type+"/"+staticArglist);
339 try {
340 Object res = linkDynamicConstantImpl(caller, bootstrapMethod, name, type, staticArguments);
341 System.out.println("linkDynamicConstantImpl => "+res);
342 return res;
343 } catch (Throwable ex) {
344 ex.printStackTrace(); // print now in case exception is swallowed
345 System.out.println("linkDynamicConstant => throw "+ex);
346 throw ex;
347 }
348 }
349
350 /** The JVM is requesting pull-mode bootstrap when it provides
351 * a tuple of the form int[]{ argc, vmindex }.
352 * The BSM is expected to call back to the JVM using the caller
353 * class and vmindex to resolve the static arguments.
354 */
355 static boolean staticArgumentsPulled(Object staticArguments) {
356 return staticArguments instanceof int[];
357 }
358
359 /** A BSM runs in pull-mode if and only if its sole arguments
360 * are (Lookup, BootstrapCallInfo), or can be converted pairwise
361 * to those types, and it is not of variable arity.
362 * Excluding error cases, we can just test that the arity is a constant 2.
363 *
364 * NOTE: This method currently returns false, since pulling is not currently
365 * exposed to a BSM. When pull mode is supported the method block will be
366 * replaced with currently commented out code.
367 */
368 static boolean isPullModeBSM(MethodHandle bsm) {
369 return false;
370 // return bsm.type().parameterCount() == 2 && !bsm.isVarargsCollector();
371 }
372
373 /**
374 * The JVM wants a pointer to a MethodType. Oblige it by finding or creating one.
375 */
376 static MethodType findMethodHandleType(Class<?> rtype, Class<?>[] ptypes) {
377 return MethodType.makeImpl(rtype, ptypes, true);
378 }
379
380 /**
381 * The JVM wants to link a call site that requires a dynamic type check.
382 * Name is a type-checking invoker, invokeExact or invoke.
383 * Return a JVM method (MemberName) to handle the invoking.
384 * The method assumes the following arguments on the stack:
385 * 0: the method handle being invoked
386 * 1-N: the arguments to the method handle invocation
387 * N+1: an optional, implicitly added argument (typically the given MethodType)
388 * <p>
389 * The nominal method at such a call site is an instance of
390 * a signature-polymorphic method (see @PolymorphicSignature).
391 * Such method instances are user-visible entities which are
392 * "split" from the generic placeholder method in {@code MethodHandle}.
393 * (Note that the placeholder method is not identical with any of
394 * its instances. If invoked reflectively, is guaranteed to throw an
395 * {@code UnsupportedOperationException}.)
396 * If the signature-polymorphic method instance is ever reified,
397 * it appears as a "copy" of the original placeholder
398 * (a native final member of {@code MethodHandle}) except
399 * that its type descriptor has shape required by the instance,
400 * and the method instance is <em>not</em> varargs.
401 * The method instance is also marked synthetic, since the
402 * method (by definition) does not appear in Java source code.
403 * <p>
404 * The JVM is allowed to reify this method as instance metadata.
405 * For example, {@code invokeBasic} is always reified.
406 * But the JVM may instead call {@code linkMethod}.
407 * If the result is an * ordered pair of a {@code (method, appendix)},
408 * the method gets all the arguments (0..N inclusive)
409 * plus the appendix (N+1), and uses the appendix to complete the call.
410 * In this way, one reusable method (called a "linker method")
411 * can perform the function of any number of polymorphic instance
412 * methods.
413 * <p>
414 * Linker methods are allowed to be weakly typed, with any or
415 * all references rewritten to {@code Object} and any primitives
416 * (except {@code long}/{@code float}/{@code double})
417 * rewritten to {@code int}.
418 * A linker method is trusted to return a strongly typed result,
419 * according to the specific method type descriptor of the
420 * signature-polymorphic instance it is emulating.
421 * This can involve (as necessary) a dynamic check using
422 * data extracted from the appendix argument.
423 * <p>
424 * The JVM does not inspect the appendix, other than to pass
425 * it verbatim to the linker method at every call.
426 * This means that the JDK runtime has wide latitude
427 * for choosing the shape of each linker method and its
428 * corresponding appendix.
429 * Linker methods should be generated from {@code LambdaForm}s
430 * so that they do not become visible on stack traces.
431 * <p>
432 * The {@code linkMethod} call is free to omit the appendix
433 * (returning null) and instead emulate the required function
434 * completely in the linker method.
435 * As a corner case, if N==255, no appendix is possible.
436 * In this case, the method returned must be custom-generated to
437 * to perform any needed type checking.
438 * <p>
439 * If the JVM does not reify a method at a call site, but instead
440 * calls {@code linkMethod}, the corresponding call represented
441 * in the bytecodes may mention a valid method which is not
442 * representable with a {@code MemberName}.
443 * Therefore, use cases for {@code linkMethod} tend to correspond to
444 * special cases in reflective code such as {@code findVirtual}
445 * or {@code revealDirect}.
446 */
447 static MemberName linkMethod(Class<?> callerClass, int refKind,
448 Class<?> defc, String name, Object type,
449 Object[] appendixResult) {
450 if (!TRACE_METHOD_LINKAGE)
451 return linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult);
452 return linkMethodTracing(callerClass, refKind, defc, name, type, appendixResult);
453 }
454 static MemberName linkMethodImpl(Class<?> callerClass, int refKind,
455 Class<?> defc, String name, Object type,
456 Object[] appendixResult) {
457 try {
458 if (refKind == REF_invokeVirtual) {
459 if (defc == MethodHandle.class) {
460 return Invokers.methodHandleInvokeLinkerMethod(
461 name, fixMethodType(callerClass, type), appendixResult);
462 } else if (defc == VarHandle.class) {
463 return varHandleOperationLinkerMethod(
464 name, fixMethodType(callerClass, type), appendixResult);
465 }
466 }
467 } catch (Error e) {
468 // Pass through an Error, including say StackOverflowError or
469 // OutOfMemoryError
470 throw e;
471 } catch (Throwable ex) {
472 // Wrap anything else in LinkageError
473 throw new LinkageError(ex.getMessage(), ex);
474 }
475 throw new LinkageError("no such method "+defc.getName()+"."+name+type);
476 }
477 private static MethodType fixMethodType(Class<?> callerClass, Object type) {
478 if (type instanceof MethodType)
479 return (MethodType) type;
480 else
481 return MethodType.fromDescriptor((String)type, callerClass.getClassLoader());
482 }
483 // Tracing logic:
484 static MemberName linkMethodTracing(Class<?> callerClass, int refKind,
485 Class<?> defc, String name, Object type,
486 Object[] appendixResult) {
487 System.out.println("linkMethod "+defc.getName()+"."+
488 name+type+"/"+Integer.toHexString(refKind));
489 try {
490 MemberName res = linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult);
491 System.out.println("linkMethod => "+res+" + "+appendixResult[0]);
492 return res;
493 } catch (Throwable ex) {
494 System.out.println("linkMethod => throw "+ex);
495 throw ex;
496 }
497 }
498
499 /**
500 * Obtain the method to link to the VarHandle operation.
501 * This method is located here and not in Invokers to avoid
502 * intializing that and other classes early on in VM bootup.
503 */
504 private static MemberName varHandleOperationLinkerMethod(String name,
505 MethodType mtype,
506 Object[] appendixResult) {
507 // Get the signature method type
508 final MethodType sigType = mtype.basicType();
509
510 // Get the access kind from the method name
511 VarHandle.AccessMode ak;
512 try {
513 ak = VarHandle.AccessMode.valueFromMethodName(name);
514 } catch (IllegalArgumentException e) {
515 throw MethodHandleStatics.newInternalError(e);
516 }
517
518 // Create the appendix descriptor constant
519 VarHandle.AccessDescriptor ad = new VarHandle.AccessDescriptor(mtype, ak.at.ordinal(), ak.ordinal());
520 appendixResult[0] = ad;
521
522 if (MethodHandleStatics.VAR_HANDLE_GUARDS) {
523 // If not polymorphic in the return type, such as the compareAndSet
524 // methods that return boolean
525 Class<?> guardReturnType = sigType.returnType();
526 if (ak.at.isMonomorphicInReturnType) {
527 if (ak.at.returnType != mtype.returnType()) {
528 // The caller contains a different return type than that
529 // defined by the method
530 throw newNoSuchMethodErrorOnVarHandle(name, mtype);
531 }
532 // Adjust the return type of the signature method type
533 guardReturnType = ak.at.returnType;
534 }
535
536 // Get the guard method type for linking
537 final Class<?>[] guardParams = new Class<?>[sigType.parameterCount() + 2];
538 // VarHandle at start
539 guardParams[0] = VarHandle.class;
540 for (int i = 0; i < sigType.parameterCount(); i++) {
541 guardParams[i + 1] = sigType.parameterType(i);
542 }
543 // Access descriptor at end
544 guardParams[guardParams.length - 1] = VarHandle.AccessDescriptor.class;
545 MethodType guardType = MethodType.makeImpl(guardReturnType, guardParams, true);
546
547 MemberName linker = new MemberName(
548 VarHandleGuards.class, getVarHandleGuardMethodName(guardType),
549 guardType, REF_invokeStatic);
550
551 linker = MemberName.getFactory().resolveOrNull(REF_invokeStatic, linker,
552 VarHandleGuards.class);
553 if (linker != null) {
554 return linker;
555 }
556 // Fall back to lambda form linkage if guard method is not available
557 // TODO Optionally log fallback ?
558 }
559 return Invokers.varHandleInvokeLinkerMethod(ak, mtype);
560 }
561 static String getVarHandleGuardMethodName(MethodType guardType) {
562 String prefix = "guard_";
563 StringBuilder sb = new StringBuilder(prefix.length() + guardType.parameterCount());
564
565 sb.append(prefix);
566 for (int i = 1; i < guardType.parameterCount() - 1; i++) {
567 Class<?> pt = guardType.parameterType(i);
568 sb.append(getCharType(pt));
569 }
570 sb.append('_').append(getCharType(guardType.returnType()));
571 return sb.toString();
572 }
573 static char getCharType(Class<?> pt) {
574 return Wrapper.forBasicType(pt).basicTypeChar();
575 }
576 static NoSuchMethodError newNoSuchMethodErrorOnVarHandle(String name, MethodType mtype) {
577 return new NoSuchMethodError("VarHandle." + name + mtype);
578 }
579
580 /**
581 * The JVM is resolving a CONSTANT_MethodHandle CP entry. And it wants our help.
582 * It will make an up-call to this method. (Do not change the name or signature.)
583 * The type argument is a Class for field requests and a MethodType for non-fields.
584 * <p>
585 * Recent versions of the JVM may also pass a resolved MemberName for the type.
586 * In that case, the name is ignored and may be null.
587 */
588 static MethodHandle linkMethodHandleConstant(Class<?> callerClass, int refKind,
589 Class<?> defc, String name, Object type) {
590 try {
591 Lookup lookup = IMPL_LOOKUP.in(callerClass);
592 assert(refKindIsValid(refKind));
593 return lookup.linkMethodHandleConstant((byte) refKind, defc, name, type);
594 } catch (ReflectiveOperationException ex) {
595 throw mapLookupExceptionToError(ex);
596 }
597 }
598
599 /**
600 * Map a reflective exception to a linkage error.
601 */
602 static LinkageError mapLookupExceptionToError(ReflectiveOperationException ex) {
603 LinkageError err;
604 if (ex instanceof IllegalAccessException) {
605 Throwable cause = ex.getCause();
606 if (cause instanceof AbstractMethodError) {
607 return (AbstractMethodError) cause;
608 } else {
609 err = new IllegalAccessError(ex.getMessage());
610 }
611 } else if (ex instanceof NoSuchMethodException) {
612 err = new NoSuchMethodError(ex.getMessage());
613 } else if (ex instanceof NoSuchFieldException) {
614 err = new NoSuchFieldError(ex.getMessage());
615 } else {
616 err = new IncompatibleClassChangeError();
617 }
618 return initCauseFrom(err, ex);
619 }
620
621 /**
622 * Use best possible cause for err.initCause(), substituting the
623 * cause for err itself if the cause has the same (or better) type.
624 */
625 static <E extends Error> E initCauseFrom(E err, Exception ex) {
626 Throwable th = ex.getCause();
627 @SuppressWarnings("unchecked")
628 final Class<E> Eclass = (Class<E>) err.getClass();
629 if (Eclass.isInstance(th))
630 return Eclass.cast(th);
631 err.initCause(th == null ? ex : th);
632 return err;
633 }
634
635 /**
636 * Is this method a caller-sensitive method?
637 * I.e., does it call Reflection.getCallerClass or a similar method
638 * to ask about the identity of its caller?
639 */
640 static boolean isCallerSensitive(MemberName mem) {
641 if (!mem.isInvocable()) return false; // fields are not caller sensitive
642
643 return mem.isCallerSensitive() || canBeCalledVirtual(mem);
644 }
645
646 static boolean canBeCalledVirtual(MemberName mem) {
647 assert(mem.isInvocable());
648 switch (mem.getName()) {
649 case "getContextClassLoader":
650 return canBeCalledVirtual(mem, java.lang.Thread.class);
651 }
652 return false;
653 }
654
655 static boolean canBeCalledVirtual(MemberName symbolicRef, Class<?> definingClass) {
656 Class<?> symbolicRefClass = symbolicRef.getDeclaringClass();
657 if (symbolicRefClass == definingClass) return true;
658 if (symbolicRef.isStatic() || symbolicRef.isPrivate()) return false;
659 return (definingClass.isAssignableFrom(symbolicRefClass) || // Msym overrides Mdef
660 symbolicRefClass.isInterface()); // Mdef implements Msym
661 }
662 }