1 /*
2 * Copyright (c) 2014, 2022, 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.value.PrimitiveClass;
29 import sun.invoke.util.Wrapper;
30
31 import java.lang.reflect.Constructor;
32 import java.lang.reflect.Field;
33 import java.lang.reflect.Method;
34 import java.lang.reflect.Modifier;
35 import java.nio.ByteOrder;
36 import java.util.ArrayList;
37 import java.util.List;
38 import java.util.Objects;
39 import java.util.concurrent.ConcurrentHashMap;
40 import java.util.concurrent.ConcurrentMap;
41 import java.util.stream.Stream;
42
43 import static java.lang.invoke.MethodHandleStatics.UNSAFE;
44 import static java.lang.invoke.MethodHandleStatics.VAR_HANDLE_IDENTITY_ADAPT;
45 import static java.lang.invoke.MethodHandleStatics.newIllegalArgumentException;
46
47 final class VarHandles {
48
49 static ClassValue<ConcurrentMap<Integer, MethodHandle>> ADDRESS_FACTORIES = new ClassValue<>() {
50 @Override
51 protected ConcurrentMap<Integer, MethodHandle> computeValue(Class<?> type) {
52 return new ConcurrentHashMap<>();
53 }
54 };
55
56 static VarHandle makeFieldHandle(MemberName f, Class<?> refc, Class<?> type, boolean isWriteAllowedOnFinalFields) {
57 if (!f.isStatic()) {
58 long foffset = MethodHandleNatives.objectFieldOffset(f);
59 if (!type.isPrimitive()) {
60 if (f.isFlattened()) {
61 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
62 ? new VarHandleValues.FieldInstanceReadOnly(refc, foffset, type)
63 : new VarHandleValues.FieldInstanceReadWrite(refc, foffset, type));
64 } else {
65 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
66 ? new VarHandleReferences.FieldInstanceReadOnly(refc, foffset, type)
67 : new VarHandleReferences.FieldInstanceReadWrite(refc, foffset, type));
68 }
69 }
70 else if (type == boolean.class) {
71 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
72 ? new VarHandleBooleans.FieldInstanceReadOnly(refc, foffset)
73 : new VarHandleBooleans.FieldInstanceReadWrite(refc, foffset));
74 }
75 else if (type == byte.class) {
76 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
77 ? new VarHandleBytes.FieldInstanceReadOnly(refc, foffset)
78 : new VarHandleBytes.FieldInstanceReadWrite(refc, foffset));
79 }
80 else if (type == short.class) {
81 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
82 ? new VarHandleShorts.FieldInstanceReadOnly(refc, foffset)
83 : new VarHandleShorts.FieldInstanceReadWrite(refc, foffset));
84 }
85 else if (type == char.class) {
86 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
87 ? new VarHandleChars.FieldInstanceReadOnly(refc, foffset)
88 : new VarHandleChars.FieldInstanceReadWrite(refc, foffset));
89 }
90 else if (type == int.class) {
91 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
92 ? new VarHandleInts.FieldInstanceReadOnly(refc, foffset)
93 : new VarHandleInts.FieldInstanceReadWrite(refc, foffset));
94 }
95 else if (type == long.class) {
96 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
97 ? new VarHandleLongs.FieldInstanceReadOnly(refc, foffset)
98 : new VarHandleLongs.FieldInstanceReadWrite(refc, foffset));
99 }
100 else if (type == float.class) {
101 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
102 ? new VarHandleFloats.FieldInstanceReadOnly(refc, foffset)
103 : new VarHandleFloats.FieldInstanceReadWrite(refc, foffset));
104 }
105 else if (type == double.class) {
106 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
107 ? new VarHandleDoubles.FieldInstanceReadOnly(refc, foffset)
108 : new VarHandleDoubles.FieldInstanceReadWrite(refc, foffset));
109 }
110 else {
111 throw new UnsupportedOperationException();
112 }
113 }
114 else {
115 // TODO This is not lazy on first invocation
116 // and might cause some circular initialization issues
117
118 // Replace with something similar to direct method handles
119 // where a barrier is used then elided after use
120
121 if (UNSAFE.shouldBeInitialized(refc))
122 UNSAFE.ensureClassInitialized(refc);
123
124 Object base = MethodHandleNatives.staticFieldBase(f);
125 long foffset = MethodHandleNatives.staticFieldOffset(f);
126 if (!type.isPrimitive()) {
127 if (f.isFlattened()) {
128 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
129 ? new VarHandleValues.FieldStaticReadOnly(refc, foffset, type)
130 : new VarHandleValues.FieldStaticReadWrite(refc, foffset, type));
131 } else {
132 return f.isFinal() && !isWriteAllowedOnFinalFields
133 ? new VarHandleReferences.FieldStaticReadOnly(base, foffset, type)
134 : new VarHandleReferences.FieldStaticReadWrite(base, foffset, type);
135 }
136 }
137 else if (type == boolean.class) {
138 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
139 ? new VarHandleBooleans.FieldStaticReadOnly(base, foffset)
140 : new VarHandleBooleans.FieldStaticReadWrite(base, foffset));
141 }
142 else if (type == byte.class) {
143 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
144 ? new VarHandleBytes.FieldStaticReadOnly(base, foffset)
145 : new VarHandleBytes.FieldStaticReadWrite(base, foffset));
146 }
147 else if (type == short.class) {
148 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
149 ? new VarHandleShorts.FieldStaticReadOnly(base, foffset)
150 : new VarHandleShorts.FieldStaticReadWrite(base, foffset));
151 }
152 else if (type == char.class) {
153 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
154 ? new VarHandleChars.FieldStaticReadOnly(base, foffset)
155 : new VarHandleChars.FieldStaticReadWrite(base, foffset));
156 }
157 else if (type == int.class) {
158 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
159 ? new VarHandleInts.FieldStaticReadOnly(base, foffset)
160 : new VarHandleInts.FieldStaticReadWrite(base, foffset));
161 }
162 else if (type == long.class) {
163 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
164 ? new VarHandleLongs.FieldStaticReadOnly(base, foffset)
165 : new VarHandleLongs.FieldStaticReadWrite(base, foffset));
166 }
167 else if (type == float.class) {
168 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
169 ? new VarHandleFloats.FieldStaticReadOnly(base, foffset)
170 : new VarHandleFloats.FieldStaticReadWrite(base, foffset));
171 }
172 else if (type == double.class) {
173 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
174 ? new VarHandleDoubles.FieldStaticReadOnly(base, foffset)
175 : new VarHandleDoubles.FieldStaticReadWrite(base, foffset));
176 }
177 else {
178 throw new UnsupportedOperationException();
179 }
180 }
181 }
182
183 // Required by instance field handles
184 static Field getFieldFromReceiverAndOffset(Class<?> receiverType,
185 long offset,
186 Class<?> fieldType) {
187 for (Field f : receiverType.getDeclaredFields()) {
188 if (Modifier.isStatic(f.getModifiers())) continue;
189
190 if (offset == UNSAFE.objectFieldOffset(f)) {
191 assert f.getType() == fieldType;
192 return f;
193 }
194 }
195 throw new InternalError("Field not found at offset");
196 }
197
198 // Required by instance static field handles
199 static Field getStaticFieldFromBaseAndOffset(Object base,
200 long offset,
201 Class<?> fieldType) {
202 // @@@ This is a little fragile assuming the base is the class
203 Class<?> receiverType = (Class<?>) base;
204 for (Field f : receiverType.getDeclaredFields()) {
205 if (!Modifier.isStatic(f.getModifiers())) continue;
206
207 if (offset == UNSAFE.staticFieldOffset(f)) {
208 assert f.getType() == fieldType;
209 return f;
210 }
211 }
212 throw new InternalError("Static field not found at offset");
213 }
214
215 static VarHandle makeArrayElementHandle(Class<?> arrayClass) {
216 if (!arrayClass.isArray())
217 throw new IllegalArgumentException("not an array: " + arrayClass);
218
219 Class<?> componentType = arrayClass.getComponentType();
220
221 int aoffset = UNSAFE.arrayBaseOffset(arrayClass);
222 int ascale = UNSAFE.arrayIndexScale(arrayClass);
223 int ashift = 31 - Integer.numberOfLeadingZeros(ascale);
224
225 if (!componentType.isPrimitive()) {
226 // the redundant componentType.isPrimitiveValueType() check is
227 // there to minimize the performance impact to non-value array.
228 // It should be removed when Unsafe::isFlattenedArray is intrinsified.
229 return maybeAdapt(PrimitiveClass.isPrimitiveValueType(componentType) && UNSAFE.isFlattenedArray(arrayClass)
230 ? new VarHandleValues.Array(aoffset, ashift, arrayClass)
231 : new VarHandleReferences.Array(aoffset, ashift, arrayClass));
232 }
233 else if (componentType == boolean.class) {
234 return maybeAdapt(new VarHandleBooleans.Array(aoffset, ashift));
235 }
236 else if (componentType == byte.class) {
237 return maybeAdapt(new VarHandleBytes.Array(aoffset, ashift));
238 }
239 else if (componentType == short.class) {
240 return maybeAdapt(new VarHandleShorts.Array(aoffset, ashift));
241 }
242 else if (componentType == char.class) {
243 return maybeAdapt(new VarHandleChars.Array(aoffset, ashift));
244 }
245 else if (componentType == int.class) {
246 return maybeAdapt(new VarHandleInts.Array(aoffset, ashift));
247 }
248 else if (componentType == long.class) {
249 return maybeAdapt(new VarHandleLongs.Array(aoffset, ashift));
250 }
251 else if (componentType == float.class) {
252 return maybeAdapt(new VarHandleFloats.Array(aoffset, ashift));
253 }
254 else if (componentType == double.class) {
255 return maybeAdapt(new VarHandleDoubles.Array(aoffset, ashift));
256 }
257 else {
258 throw new UnsupportedOperationException();
259 }
260 }
261
262 static VarHandle byteArrayViewHandle(Class<?> viewArrayClass,
263 boolean be) {
264 if (!viewArrayClass.isArray())
265 throw new IllegalArgumentException("not an array: " + viewArrayClass);
266
267 Class<?> viewComponentType = viewArrayClass.getComponentType();
268
269 if (viewComponentType == long.class) {
270 return maybeAdapt(new VarHandleByteArrayAsLongs.ArrayHandle(be));
271 }
272 else if (viewComponentType == int.class) {
273 return maybeAdapt(new VarHandleByteArrayAsInts.ArrayHandle(be));
274 }
275 else if (viewComponentType == short.class) {
276 return maybeAdapt(new VarHandleByteArrayAsShorts.ArrayHandle(be));
277 }
278 else if (viewComponentType == char.class) {
279 return maybeAdapt(new VarHandleByteArrayAsChars.ArrayHandle(be));
280 }
281 else if (viewComponentType == double.class) {
282 return maybeAdapt(new VarHandleByteArrayAsDoubles.ArrayHandle(be));
283 }
284 else if (viewComponentType == float.class) {
285 return maybeAdapt(new VarHandleByteArrayAsFloats.ArrayHandle(be));
286 }
287
288 throw new UnsupportedOperationException();
289 }
290
291 static VarHandle makeByteBufferViewHandle(Class<?> viewArrayClass,
292 boolean be) {
293 if (!viewArrayClass.isArray())
294 throw new IllegalArgumentException("not an array: " + viewArrayClass);
295
296 Class<?> viewComponentType = viewArrayClass.getComponentType();
297
298 if (viewComponentType == long.class) {
299 return maybeAdapt(new VarHandleByteArrayAsLongs.ByteBufferHandle(be));
300 }
301 else if (viewComponentType == int.class) {
302 return maybeAdapt(new VarHandleByteArrayAsInts.ByteBufferHandle(be));
303 }
304 else if (viewComponentType == short.class) {
305 return maybeAdapt(new VarHandleByteArrayAsShorts.ByteBufferHandle(be));
306 }
307 else if (viewComponentType == char.class) {
308 return maybeAdapt(new VarHandleByteArrayAsChars.ByteBufferHandle(be));
309 }
310 else if (viewComponentType == double.class) {
311 return maybeAdapt(new VarHandleByteArrayAsDoubles.ByteBufferHandle(be));
312 }
313 else if (viewComponentType == float.class) {
314 return maybeAdapt(new VarHandleByteArrayAsFloats.ByteBufferHandle(be));
315 }
316
317 throw new UnsupportedOperationException();
318 }
319
320 /**
321 * Creates a memory segment view var handle.
322 *
323 * The resulting var handle will take a memory segment as first argument (the segment to be dereferenced),
324 * and a {@code long} as second argument (the offset into the segment).
325 *
326 * @param carrier the Java carrier type.
327 * @param alignmentMask alignment requirement to be checked upon access. In bytes. Expressed as a mask.
328 * @param byteOrder the byte order.
329 * @return the created VarHandle.
330 */
331 static VarHandle memorySegmentViewHandle(Class<?> carrier, long alignmentMask,
332 ByteOrder byteOrder) {
333 if (!carrier.isPrimitive() || carrier == void.class || carrier == boolean.class) {
334 throw new IllegalArgumentException("Invalid carrier: " + carrier.getName());
335 }
336 long size = Wrapper.forPrimitiveType(carrier).bitWidth() / 8;
337 boolean be = byteOrder == ByteOrder.BIG_ENDIAN;
338 boolean exact = false;
339
340 if (carrier == byte.class) {
341 return maybeAdapt(new VarHandleSegmentAsBytes(be, size, alignmentMask, exact));
342 } else if (carrier == char.class) {
343 return maybeAdapt(new VarHandleSegmentAsChars(be, size, alignmentMask, exact));
344 } else if (carrier == short.class) {
345 return maybeAdapt(new VarHandleSegmentAsShorts(be, size, alignmentMask, exact));
346 } else if (carrier == int.class) {
347 return maybeAdapt(new VarHandleSegmentAsInts(be, size, alignmentMask, exact));
348 } else if (carrier == float.class) {
349 return maybeAdapt(new VarHandleSegmentAsFloats(be, size, alignmentMask, exact));
350 } else if (carrier == long.class) {
351 return maybeAdapt(new VarHandleSegmentAsLongs(be, size, alignmentMask, exact));
352 } else if (carrier == double.class) {
353 return maybeAdapt(new VarHandleSegmentAsDoubles(be, size, alignmentMask, exact));
354 } else {
355 throw new IllegalStateException("Cannot get here");
356 }
357 }
358
359 private static VarHandle maybeAdapt(VarHandle target) {
360 if (!VAR_HANDLE_IDENTITY_ADAPT) return target;
361 target = filterValue(target,
362 MethodHandles.identity(target.varType()), MethodHandles.identity(target.varType()));
363 MethodType mtype = target.accessModeType(VarHandle.AccessMode.GET);
364 for (int i = 0 ; i < mtype.parameterCount() ; i++) {
365 target = filterCoordinates(target, i, MethodHandles.identity(mtype.parameterType(i)));
366 }
367 return target;
368 }
369
370 public static VarHandle filterValue(VarHandle target, MethodHandle pFilterToTarget, MethodHandle pFilterFromTarget) {
371 Objects.requireNonNull(target);
372 Objects.requireNonNull(pFilterToTarget);
373 Objects.requireNonNull(pFilterFromTarget);
374 //check that from/to filters do not throw checked exceptions
375 MethodHandle filterToTarget = adaptForCheckedExceptions(pFilterToTarget);
376 MethodHandle filterFromTarget = adaptForCheckedExceptions(pFilterFromTarget);
377
378 List<Class<?>> newCoordinates = new ArrayList<>();
379 List<Class<?>> additionalCoordinates = new ArrayList<>();
380 newCoordinates.addAll(target.coordinateTypes());
381
382 //check that from/to filters have right signatures
383 if (filterFromTarget.type().parameterCount() != filterToTarget.type().parameterCount()) {
384 throw newIllegalArgumentException("filterFromTarget and filterToTarget have different arity", filterFromTarget.type(), filterToTarget.type());
385 } else if (filterFromTarget.type().parameterCount() < 1) {
386 throw newIllegalArgumentException("filterFromTarget filter type has wrong arity", filterFromTarget.type());
387 } else if (filterToTarget.type().parameterCount() < 1) {
388 throw newIllegalArgumentException("filterToTarget filter type has wrong arity", filterFromTarget.type());
389 } else if (filterFromTarget.type().lastParameterType() != filterToTarget.type().returnType() ||
390 filterToTarget.type().lastParameterType() != filterFromTarget.type().returnType()) {
391 throw newIllegalArgumentException("filterFromTarget and filterToTarget filter types do not match", filterFromTarget.type(), filterToTarget.type());
392 } else if (target.varType() != filterFromTarget.type().lastParameterType()) {
393 throw newIllegalArgumentException("filterFromTarget filter type does not match target var handle type", filterFromTarget.type(), target.varType());
394 } else if (target.varType() != filterToTarget.type().returnType()) {
395 throw newIllegalArgumentException("filterFromTarget filter type does not match target var handle type", filterToTarget.type(), target.varType());
396 } else if (filterFromTarget.type().parameterCount() > 1) {
397 for (int i = 0 ; i < filterFromTarget.type().parameterCount() - 1 ; i++) {
398 if (filterFromTarget.type().parameterType(i) != filterToTarget.type().parameterType(i)) {
399 throw newIllegalArgumentException("filterFromTarget and filterToTarget filter types do not match", filterFromTarget.type(), filterToTarget.type());
400 } else {
401 newCoordinates.add(filterFromTarget.type().parameterType(i));
402 additionalCoordinates.add((filterFromTarget.type().parameterType(i)));
403 }
404 }
405 }
406
407 return new IndirectVarHandle(target, filterFromTarget.type().returnType(), newCoordinates.toArray(new Class<?>[0]),
408 (mode, modeHandle) -> {
409 int lastParameterPos = modeHandle.type().parameterCount() - 1;
410 return switch (mode.at) {
411 case GET -> MethodHandles.collectReturnValue(modeHandle, filterFromTarget);
412 case SET -> MethodHandles.collectArguments(modeHandle, lastParameterPos, filterToTarget);
413 case GET_AND_UPDATE -> {
414 MethodHandle adapter = MethodHandles.collectReturnValue(modeHandle, filterFromTarget);
415 MethodHandle res = MethodHandles.collectArguments(adapter, lastParameterPos, filterToTarget);
416 if (additionalCoordinates.size() > 0) {
417 res = joinDuplicateArgs(res, lastParameterPos,
418 lastParameterPos + additionalCoordinates.size() + 1,
419 additionalCoordinates.size());
420 }
421 yield res;
422 }
423 case COMPARE_AND_EXCHANGE -> {
424 MethodHandle adapter = MethodHandles.collectReturnValue(modeHandle, filterFromTarget);
425 adapter = MethodHandles.collectArguments(adapter, lastParameterPos, filterToTarget);
426 if (additionalCoordinates.size() > 0) {
427 adapter = joinDuplicateArgs(adapter, lastParameterPos,
428 lastParameterPos + additionalCoordinates.size() + 1,
429 additionalCoordinates.size());
430 }
431 MethodHandle res = MethodHandles.collectArguments(adapter, lastParameterPos - 1, filterToTarget);
432 if (additionalCoordinates.size() > 0) {
433 res = joinDuplicateArgs(res, lastParameterPos - 1,
434 lastParameterPos + additionalCoordinates.size(),
435 additionalCoordinates.size());
436 }
437 yield res;
438 }
439 case COMPARE_AND_SET -> {
440 MethodHandle adapter = MethodHandles.collectArguments(modeHandle, lastParameterPos, filterToTarget);
441 MethodHandle res = MethodHandles.collectArguments(adapter, lastParameterPos - 1, filterToTarget);
442 if (additionalCoordinates.size() > 0) {
443 res = joinDuplicateArgs(res, lastParameterPos - 1,
444 lastParameterPos + additionalCoordinates.size(),
445 additionalCoordinates.size());
446 }
447 yield res;
448 }
449 };
450 });
451 }
452
453 private static MethodHandle joinDuplicateArgs(MethodHandle handle, int originalStart, int dropStart, int length) {
454 int[] perms = new int[handle.type().parameterCount()];
455 for (int i = 0 ; i < dropStart; i++) {
456 perms[i] = i;
457 }
458 for (int i = 0 ; i < length ; i++) {
459 perms[dropStart + i] = originalStart + i;
460 }
461 for (int i = dropStart + length ; i < perms.length ; i++) {
462 perms[i] = i - length;
463 }
464 return MethodHandles.permuteArguments(handle,
465 handle.type().dropParameterTypes(dropStart, dropStart + length),
466 perms);
467 }
468
469 public static VarHandle filterCoordinates(VarHandle target, int pos, MethodHandle... filters) {
470 Objects.requireNonNull(target);
471 Objects.requireNonNull(filters);
472
473 List<Class<?>> targetCoordinates = target.coordinateTypes();
474 if (pos < 0 || pos >= targetCoordinates.size()) {
475 throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
476 } else if (pos + filters.length > targetCoordinates.size()) {
477 throw new IllegalArgumentException("Too many filters");
478 }
479
480 if (filters.length == 0) return target;
481
482 List<Class<?>> newCoordinates = new ArrayList<>(targetCoordinates);
483 for (int i = 0 ; i < filters.length ; i++) {
484 MethodHandle filter = Objects.requireNonNull(filters[i]);
485 filter = adaptForCheckedExceptions(filter);
486 MethodType filterType = filter.type();
487 if (filterType.parameterCount() != 1) {
488 throw newIllegalArgumentException("Invalid filter type " + filterType);
489 } else if (newCoordinates.get(pos + i) != filterType.returnType()) {
490 throw newIllegalArgumentException("Invalid filter type " + filterType + " for coordinate type " + newCoordinates.get(i));
491 }
492 newCoordinates.set(pos + i, filters[i].type().parameterType(0));
493 }
494
495 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
496 (mode, modeHandle) -> MethodHandles.filterArguments(modeHandle, 1 + pos, filters));
497 }
498
499 public static VarHandle insertCoordinates(VarHandle target, int pos, Object... values) {
500 Objects.requireNonNull(target);
501 Objects.requireNonNull(values);
502
503 List<Class<?>> targetCoordinates = target.coordinateTypes();
504 if (pos < 0 || pos >= targetCoordinates.size()) {
505 throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
506 } else if (pos + values.length > targetCoordinates.size()) {
507 throw new IllegalArgumentException("Too many values");
508 }
509
510 if (values.length == 0) return target;
511
512 List<Class<?>> newCoordinates = new ArrayList<>(targetCoordinates);
513 for (int i = 0 ; i < values.length ; i++) {
514 Class<?> pt = newCoordinates.get(pos);
515 if (pt.isPrimitive()) {
516 Wrapper w = Wrapper.forPrimitiveType(pt);
517 w.convert(values[i], pt);
518 } else {
519 pt.cast(values[i]);
520 }
521 newCoordinates.remove(pos);
522 }
523
524 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
525 (mode, modeHandle) -> MethodHandles.insertArguments(modeHandle, 1 + pos, values));
526 }
527
528 public static VarHandle permuteCoordinates(VarHandle target, List<Class<?>> newCoordinates, int... reorder) {
529 Objects.requireNonNull(target);
530 Objects.requireNonNull(newCoordinates);
531 Objects.requireNonNull(reorder);
532
533 List<Class<?>> targetCoordinates = target.coordinateTypes();
534 MethodHandles.permuteArgumentChecks(reorder,
535 MethodType.methodType(void.class, newCoordinates),
536 MethodType.methodType(void.class, targetCoordinates));
537
538 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
539 (mode, modeHandle) ->
540 MethodHandles.permuteArguments(modeHandle,
541 methodTypeFor(mode.at, modeHandle.type(), targetCoordinates, newCoordinates),
542 reorderArrayFor(mode.at, newCoordinates, reorder)));
543 }
544
545 private static int numTrailingArgs(VarHandle.AccessType at) {
546 return switch (at) {
547 case GET -> 0;
548 case GET_AND_UPDATE, SET -> 1;
549 case COMPARE_AND_SET, COMPARE_AND_EXCHANGE -> 2;
550 };
551 }
552
553 private static int[] reorderArrayFor(VarHandle.AccessType at, List<Class<?>> newCoordinates, int[] reorder) {
554 int numTrailingArgs = numTrailingArgs(at);
555 int[] adjustedReorder = new int[reorder.length + 1 + numTrailingArgs];
556 adjustedReorder[0] = 0;
557 for (int i = 0 ; i < reorder.length ; i++) {
558 adjustedReorder[i + 1] = reorder[i] + 1;
559 }
560 for (int i = 0 ; i < numTrailingArgs ; i++) {
561 adjustedReorder[i + reorder.length + 1] = i + newCoordinates.size() + 1;
562 }
563 return adjustedReorder;
564 }
565
566 private static MethodType methodTypeFor(VarHandle.AccessType at, MethodType oldType, List<Class<?>> oldCoordinates, List<Class<?>> newCoordinates) {
567 int numTrailingArgs = numTrailingArgs(at);
568 MethodType adjustedType = MethodType.methodType(oldType.returnType(), oldType.parameterType(0));
569 adjustedType = adjustedType.appendParameterTypes(newCoordinates);
570 for (int i = 0 ; i < numTrailingArgs ; i++) {
571 adjustedType = adjustedType.appendParameterTypes(oldType.parameterType(1 + oldCoordinates.size() + i));
572 }
573 return adjustedType;
574 }
575
576 public static VarHandle collectCoordinates(VarHandle target, int pos, MethodHandle pFilter) {
577 Objects.requireNonNull(target);
578 Objects.requireNonNull(pFilter);
579 MethodHandle filter = adaptForCheckedExceptions(pFilter);
580
581 List<Class<?>> targetCoordinates = target.coordinateTypes();
582 if (pos < 0 || pos >= targetCoordinates.size()) {
583 throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
584 } else if (filter.type().returnType() == void.class) {
585 throw newIllegalArgumentException("Invalid filter type " + filter.type() + " ; filter cannot be void");
586 } else if (filter.type().returnType() != targetCoordinates.get(pos)) {
587 throw newIllegalArgumentException("Invalid filter type " + filter.type() + " for coordinate type " + targetCoordinates.get(pos));
588 }
589
590 List<Class<?>> newCoordinates = new ArrayList<>(targetCoordinates);
591 newCoordinates.remove(pos);
592 newCoordinates.addAll(pos, filter.type().parameterList());
593
594 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
595 (mode, modeHandle) -> MethodHandles.collectArguments(modeHandle, 1 + pos, filter));
596 }
597
598 public static VarHandle dropCoordinates(VarHandle target, int pos, Class<?>... valueTypes) {
599 Objects.requireNonNull(target);
600 Objects.requireNonNull(valueTypes);
601
602 List<Class<?>> targetCoordinates = target.coordinateTypes();
603 if (pos < 0 || pos > targetCoordinates.size()) {
604 throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
605 }
606
607 if (valueTypes.length == 0) return target;
608
609 List<Class<?>> newCoordinates = new ArrayList<>(targetCoordinates);
610 newCoordinates.addAll(pos, List.of(valueTypes));
611
612 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
613 (mode, modeHandle) -> MethodHandles.dropArguments(modeHandle, 1 + pos, valueTypes));
614 }
615
616 private static MethodHandle adaptForCheckedExceptions(MethodHandle target) {
617 Class<?>[] exceptionTypes = exceptionTypes(target);
618 if (exceptionTypes != null) { // exceptions known
619 if (Stream.of(exceptionTypes).anyMatch(VarHandles::isCheckedException)) {
620 throw newIllegalArgumentException("Cannot adapt a var handle with a method handle which throws checked exceptions");
621 }
622 return target; // no adaptation needed
623 } else {
624 MethodHandle handler = MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_VarHandles_handleCheckedExceptions);
625 MethodHandle zero = MethodHandles.zero(target.type().returnType()); // dead branch
626 handler = MethodHandles.collectArguments(zero, 0, handler);
627 return MethodHandles.catchException(target, Throwable.class, handler);
628 }
629 }
630
631 static void handleCheckedExceptions(Throwable throwable) throws Throwable {
632 if (isCheckedException(throwable.getClass())) {
633 throw new IllegalStateException("Adapter handle threw checked exception", throwable);
634 }
635 throw throwable;
636 }
637
638 static Class<?>[] exceptionTypes(MethodHandle handle) {
639 if (handle instanceof DirectMethodHandle directHandle) {
640 byte refKind = directHandle.member.getReferenceKind();
641 MethodHandleInfo info = new InfoFromMemberName(
642 MethodHandles.Lookup.IMPL_LOOKUP,
643 directHandle.member,
644 refKind);
645 if (MethodHandleNatives.refKindIsMethod(refKind)) {
646 return info.reflectAs(Method.class, MethodHandles.Lookup.IMPL_LOOKUP)
647 .getExceptionTypes();
648 } else if (MethodHandleNatives.refKindIsField(refKind)) {
649 return new Class<?>[0];
650 } else if (MethodHandleNatives.refKindIsObjectConstructor(refKind)) {
651 return info.reflectAs(Constructor.class, MethodHandles.Lookup.IMPL_LOOKUP)
652 .getExceptionTypes();
653 } else {
654 throw new AssertionError("Cannot get here");
655 }
656 } else if (handle instanceof DelegatingMethodHandle) {
657 return exceptionTypes(((DelegatingMethodHandle)handle).getTarget());
658 } else if (handle instanceof NativeMethodHandle) {
659 return new Class<?>[0];
660 }
661
662 assert handle instanceof BoundMethodHandle : "Unexpected handle type: " + handle;
663 // unknown
664 return null;
665 }
666
667 private static boolean isCheckedException(Class<?> clazz) {
668 return Throwable.class.isAssignableFrom(clazz) &&
669 !RuntimeException.class.isAssignableFrom(clazz) &&
670 !Error.class.isAssignableFrom(clazz);
671 }
672
673 // /**
674 // * A helper program to generate the VarHandleGuards class with a set of
675 // * static guard methods each of which corresponds to a particular shape and
676 // * performs a type check of the symbolic type descriptor with the VarHandle
677 // * type descriptor before linking/invoking to the underlying operation as
678 // * characterized by the operation member name on the VarForm of the
679 // * VarHandle.
680 // * <p>
681 // * The generated class essentially encapsulates pre-compiled LambdaForms,
682 // * one for each method, for the most set of common method signatures.
683 // * This reduces static initialization costs, footprint costs, and circular
684 // * dependencies that may arise if a class is generated per LambdaForm.
685 // * <p>
686 // * A maximum of L*T*S methods will be generated where L is the number of
687 // * access modes kinds (or unique operation signatures) and T is the number
688 // * of variable types and S is the number of shapes (such as instance field,
689 // * static field, or array access).
690 // * If there are 4 unique operation signatures, 5 basic types (Object, int,
691 // * long, float, double), and 3 shapes then a maximum of 60 methods will be
692 // * generated. However, the number is likely to be less since there
693 // * be duplicate signatures.
694 // * <p>
695 // * Each method is annotated with @LambdaForm.Compiled to inform the runtime
696 // * that such methods should be treated as if a method of a class that is the
697 // * result of compiling a LambdaForm. Annotation of such methods is
698 // * important for correct evaluation of certain assertions and method return
699 // * type profiling in HotSpot.
700 // */
701 // public static class GuardMethodGenerator {
702 //
703 // static final String GUARD_METHOD_SIG_TEMPLATE = "<RETURN> <NAME>_<SIGNATURE>(<PARAMS>)";
704 //
705 // static final String GUARD_METHOD_TEMPLATE =
706 // """
707 // @ForceInline
708 // @LambdaForm.Compiled
709 // @Hidden
710 // static final <METHOD> throws Throwable {
711 // boolean direct = handle.checkAccessModeThenIsDirect(ad);
712 // if (direct && handle.vform.methodType_table[ad.type] == ad.symbolicMethodTypeErased) {
713 // <RESULT_ERASED>MethodHandle.linkToStatic(<LINK_TO_STATIC_ARGS>);<RETURN_ERASED>
714 // } else {
715 // MethodHandle mh = handle.getMethodHandle(ad.mode);
716 // <RETURN>mh.asType(ad.symbolicMethodTypeInvoker).invokeBasic(<LINK_TO_INVOKER_ARGS>);
717 // }
718 // }""";
719 //
720 // static final String GUARD_METHOD_TEMPLATE_V =
721 // """
722 // @ForceInline
723 // @LambdaForm.Compiled
724 // @Hidden
725 // static final <METHOD> throws Throwable {
726 // boolean direct = handle.checkAccessModeThenIsDirect(ad);
727 // if (direct && handle.vform.methodType_table[ad.type] == ad.symbolicMethodTypeErased) {
728 // MethodHandle.linkToStatic(<LINK_TO_STATIC_ARGS>);
729 // } else if (direct && handle.vform.getMethodType_V(ad.type) == ad.symbolicMethodTypeErased) {
730 // MethodHandle.linkToStatic(<LINK_TO_STATIC_ARGS>);
731 // } else {
732 // MethodHandle mh = handle.getMethodHandle(ad.mode);
733 // mh.asType(ad.symbolicMethodTypeInvoker).invokeBasic(<LINK_TO_INVOKER_ARGS>);
734 // }
735 // }""";
736 //
737 // // A template for deriving the operations
738 // // could be supported by annotating VarHandle directly with the
739 // // operation kind and shape
740 // interface VarHandleTemplate {
741 // Object get();
742 //
743 // void set(Object value);
744 //
745 // boolean compareAndSet(Object actualValue, Object expectedValue);
746 //
747 // Object compareAndExchange(Object actualValue, Object expectedValue);
748 //
749 // Object getAndUpdate(Object value);
750 // }
751 //
752 // static class HandleType {
753 // final Class<?> receiver;
754 // final Class<?>[] intermediates;
755 // final Class<?> value;
756 //
757 // HandleType(Class<?> receiver, Class<?> value, Class<?>... intermediates) {
758 // this.receiver = receiver;
759 // this.intermediates = intermediates;
760 // this.value = value;
761 // }
762 // }
763 //
764 // /**
765 // * @param args parameters
766 // */
767 // public static void main(String[] args) {
768 // System.out.println("package java.lang.invoke;");
769 // System.out.println();
770 // System.out.println("import jdk.internal.vm.annotation.ForceInline;");
771 // System.out.println("import jdk.internal.vm.annotation.Hidden;");
772 // System.out.println();
773 // System.out.println("// This class is auto-generated by " +
774 // GuardMethodGenerator.class.getName() +
775 // ". Do not edit.");
776 // System.out.println("final class VarHandleGuards {");
777 //
778 // System.out.println();
779 //
780 // // Declare the stream of shapes
781 // Stream<HandleType> hts = Stream.of(
782 // // Object->Object
783 // new HandleType(Object.class, Object.class),
784 // // Object->int
785 // new HandleType(Object.class, int.class),
786 // // Object->long
787 // new HandleType(Object.class, long.class),
788 // // Object->float
789 // new HandleType(Object.class, float.class),
790 // // Object->double
791 // new HandleType(Object.class, double.class),
792 //
793 // // <static>->Object
794 // new HandleType(null, Object.class),
795 // // <static>->int
796 // new HandleType(null, int.class),
797 // // <static>->long
798 // new HandleType(null, long.class),
799 // // <static>->float
800 // new HandleType(null, float.class),
801 // // <static>->double
802 // new HandleType(null, double.class),
803 //
804 // // Array[int]->Object
805 // new HandleType(Object.class, Object.class, int.class),
806 // // Array[int]->int
807 // new HandleType(Object.class, int.class, int.class),
808 // // Array[int]->long
809 // new HandleType(Object.class, long.class, int.class),
810 // // Array[int]->float
811 // new HandleType(Object.class, float.class, int.class),
812 // // Array[int]->double
813 // new HandleType(Object.class, double.class, int.class),
814 //
815 // // Array[long]->int
816 // new HandleType(Object.class, int.class, long.class),
817 // // Array[long]->long
818 // new HandleType(Object.class, long.class, long.class)
819 // );
820 //
821 // hts.flatMap(ht -> Stream.of(VarHandleTemplate.class.getMethods()).
822 // map(m -> generateMethodType(m, ht.receiver, ht.value, ht.intermediates))).
823 // distinct().
824 // map(GuardMethodGenerator::generateMethod).
825 // forEach(System.out::println);
826 //
827 // System.out.println("}");
828 // }
829 //
830 // static MethodType generateMethodType(Method m, Class<?> receiver, Class<?> value, Class<?>... intermediates) {
831 // Class<?> returnType = m.getReturnType() == Object.class
832 // ? value : m.getReturnType();
833 //
834 // List<Class<?>> params = new ArrayList<>();
835 // if (receiver != null)
836 // params.add(receiver);
837 // for (int i = 0; i < intermediates.length; i++) {
838 // params.add(intermediates[i]);
839 // }
840 // for (Parameter p : m.getParameters()) {
841 // params.add(value);
842 // }
843 // return MethodType.methodType(returnType, params);
844 // }
845 //
846 // static String generateMethod(MethodType mt) {
847 // Class<?> returnType = mt.returnType();
848 //
849 // LinkedHashMap<String, Class<?>> params = new LinkedHashMap<>();
850 // params.put("handle", VarHandle.class);
851 // for (int i = 0; i < mt.parameterCount(); i++) {
852 // params.put("arg" + i, mt.parameterType(i));
853 // }
854 // params.put("ad", VarHandle.AccessDescriptor.class);
855 //
856 // // Generate method signature line
857 // String RETURN = className(returnType);
858 // String NAME = "guard";
859 // String SIGNATURE = getSignature(mt);
860 // String PARAMS = params.entrySet().stream().
861 // map(e -> className(e.getValue()) + " " + e.getKey()).
862 // collect(joining(", "));
863 // String METHOD = GUARD_METHOD_SIG_TEMPLATE.
864 // replace("<RETURN>", RETURN).
865 // replace("<NAME>", NAME).
866 // replace("<SIGNATURE>", SIGNATURE).
867 // replace("<PARAMS>", PARAMS);
868 //
869 // // Generate method
870 // params.remove("ad");
871 //
872 // List<String> LINK_TO_STATIC_ARGS = params.keySet().stream().
873 // collect(toList());
874 // LINK_TO_STATIC_ARGS.add("handle.vform.getMemberName(ad.mode)");
875 //
876 // List<String> LINK_TO_INVOKER_ARGS = params.keySet().stream().
877 // collect(toList());
878 // LINK_TO_INVOKER_ARGS.set(0, LINK_TO_INVOKER_ARGS.get(0) + ".asDirect()");
879 //
880 // RETURN = returnType == void.class
881 // ? ""
882 // : returnType == Object.class
883 // ? "return "
884 // : "return (" + returnType.getName() + ") ";
885 //
886 // String RESULT_ERASED = returnType == void.class
887 // ? ""
888 // : returnType != Object.class
889 // ? "return (" + returnType.getName() + ") "
890 // : "Object r = ";
891 //
892 // String RETURN_ERASED = returnType != Object.class
893 // ? ""
894 // : "\n return ad.returnType.cast(r);";
895 //
896 // String template = returnType == void.class
897 // ? GUARD_METHOD_TEMPLATE_V
898 // : GUARD_METHOD_TEMPLATE;
899 // return template.
900 // replace("<METHOD>", METHOD).
901 // replace("<NAME>", NAME).
902 // replaceAll("<RETURN>", RETURN).
903 // replace("<RESULT_ERASED>", RESULT_ERASED).
904 // replace("<RETURN_ERASED>", RETURN_ERASED).
905 // replaceAll("<LINK_TO_STATIC_ARGS>", LINK_TO_STATIC_ARGS.stream().
906 // collect(joining(", "))).
907 // replace("<LINK_TO_INVOKER_ARGS>", LINK_TO_INVOKER_ARGS.stream().
908 // collect(joining(", ")))
909 // .indent(4);
910 // }
911 //
912 // static String className(Class<?> c) {
913 // String n = c.getName();
914 // if (n.startsWith("java.lang.")) {
915 // n = n.replace("java.lang.", "");
916 // if (n.startsWith("invoke.")) {
917 // n = n.replace("invoke.", "");
918 // }
919 // }
920 // return n.replace('$', '.');
921 // }
922 //
923 // static String getSignature(MethodType m) {
924 // StringBuilder sb = new StringBuilder(m.parameterCount() + 1);
925 //
926 // for (int i = 0; i < m.parameterCount(); i++) {
927 // Class<?> pt = m.parameterType(i);
928 // sb.append(getCharType(pt));
929 // }
930 //
931 // sb.append('_').append(getCharType(m.returnType()));
932 //
933 // return sb.toString();
934 // }
935 //
936 // static char getCharType(Class<?> pt) {
937 // if (pt == void.class) {
938 // return 'V';
939 // }
940 // else if (!pt.isPrimitive()) {
941 // return 'L';
942 // }
943 // else if (pt == boolean.class) {
944 // return 'Z';
945 // }
946 // else if (pt == int.class) {
947 // return 'I';
948 // }
949 // else if (pt == long.class) {
950 // return 'J';
951 // }
952 // else if (pt == float.class) {
953 // return 'F';
954 // }
955 // else if (pt == double.class) {
956 // return 'D';
957 // }
958 // else {
959 // throw new IllegalStateException(pt.getName());
960 // }
961 // }
962 // }
963 }