1 /*
2 * Copyright (c) 2014, 2023, 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.foreign.Utils;
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_SEGMENT_FORCE_EXACT;
45 import static java.lang.invoke.MethodHandleStatics.VAR_HANDLE_IDENTITY_ADAPT;
46 import static java.lang.invoke.MethodHandleStatics.newIllegalArgumentException;
47
48 final class VarHandles {
49
50 static ClassValue<ConcurrentMap<Integer, MethodHandle>> ADDRESS_FACTORIES = new ClassValue<>() {
51 @Override
52 protected ConcurrentMap<Integer, MethodHandle> computeValue(Class<?> type) {
53 return new ConcurrentHashMap<>();
54 }
55 };
56
57 static VarHandle makeFieldHandle(MemberName f, Class<?> refc, boolean isWriteAllowedOnFinalFields) {
58 if (!f.isStatic()) {
59 long foffset = MethodHandleNatives.objectFieldOffset(f);
60 Class<?> type = f.getFieldType();
61 if (!type.isPrimitive()) {
62 if (f.isFlat()) {
63 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
64 ? new VarHandleValues.FieldInstanceReadOnly(refc, foffset, type, f.getCheckedFieldType())
65 : new VarHandleValues.FieldInstanceReadWrite(refc, foffset, type, f.getCheckedFieldType()));
66 } else {
67 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
68 ? new VarHandleReferences.FieldInstanceReadOnly(refc, foffset, type, f.getCheckedFieldType())
69 : new VarHandleReferences.FieldInstanceReadWrite(refc, foffset, type, f.getCheckedFieldType()));
70 }
71 }
72 else if (type == boolean.class) {
73 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
74 ? new VarHandleBooleans.FieldInstanceReadOnly(refc, foffset)
75 : new VarHandleBooleans.FieldInstanceReadWrite(refc, foffset));
76 }
77 else if (type == byte.class) {
78 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
79 ? new VarHandleBytes.FieldInstanceReadOnly(refc, foffset)
80 : new VarHandleBytes.FieldInstanceReadWrite(refc, foffset));
81 }
82 else if (type == short.class) {
83 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
84 ? new VarHandleShorts.FieldInstanceReadOnly(refc, foffset)
85 : new VarHandleShorts.FieldInstanceReadWrite(refc, foffset));
86 }
87 else if (type == char.class) {
88 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
89 ? new VarHandleChars.FieldInstanceReadOnly(refc, foffset)
90 : new VarHandleChars.FieldInstanceReadWrite(refc, foffset));
91 }
92 else if (type == int.class) {
93 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
94 ? new VarHandleInts.FieldInstanceReadOnly(refc, foffset)
95 : new VarHandleInts.FieldInstanceReadWrite(refc, foffset));
96 }
97 else if (type == long.class) {
98 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
99 ? new VarHandleLongs.FieldInstanceReadOnly(refc, foffset)
100 : new VarHandleLongs.FieldInstanceReadWrite(refc, foffset));
101 }
102 else if (type == float.class) {
103 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
104 ? new VarHandleFloats.FieldInstanceReadOnly(refc, foffset)
105 : new VarHandleFloats.FieldInstanceReadWrite(refc, foffset));
106 }
107 else if (type == double.class) {
108 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
109 ? new VarHandleDoubles.FieldInstanceReadOnly(refc, foffset)
110 : new VarHandleDoubles.FieldInstanceReadWrite(refc, foffset));
111 }
112 else {
113 throw new UnsupportedOperationException();
114 }
115 }
116 else {
117 Class<?> decl = f.getDeclaringClass();
118 var vh = makeStaticFieldVarHandle(decl, f, isWriteAllowedOnFinalFields);
119 return maybeAdapt(UNSAFE.shouldBeInitialized(decl)
120 ? new LazyInitializingVarHandle(vh, decl)
121 : vh);
122 }
123 }
124
125 static VarHandle makeStaticFieldVarHandle(Class<?> decl, MemberName f, boolean isWriteAllowedOnFinalFields) {
126 Object base = MethodHandleNatives.staticFieldBase(f);
127 long foffset = MethodHandleNatives.staticFieldOffset(f);
128 Class<?> type = f.getFieldType();
129 if (!type.isPrimitive()) {
130 if (f.isFlat()) {
131 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
132 ? new VarHandleValues.FieldStaticReadOnly(decl, base, foffset, type, f.getCheckedFieldType())
133 : new VarHandleValues.FieldStaticReadWrite(decl, base, foffset, type, f.getCheckedFieldType()));
134 } else {
135 return f.isFinal() && !isWriteAllowedOnFinalFields
136 ? new VarHandleReferences.FieldStaticReadOnly(decl, base, foffset, type, f.getCheckedFieldType())
137 : new VarHandleReferences.FieldStaticReadWrite(decl, base, foffset, type, f.getCheckedFieldType());
138 }
139 }
140 else if (type == boolean.class) {
141 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
142 ? new VarHandleBooleans.FieldStaticReadOnly(decl, base, foffset)
143 : new VarHandleBooleans.FieldStaticReadWrite(decl, base, foffset));
144 }
145 else if (type == byte.class) {
146 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
147 ? new VarHandleBytes.FieldStaticReadOnly(decl, base, foffset)
148 : new VarHandleBytes.FieldStaticReadWrite(decl, base, foffset));
149 }
150 else if (type == short.class) {
151 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
152 ? new VarHandleShorts.FieldStaticReadOnly(decl, base, foffset)
153 : new VarHandleShorts.FieldStaticReadWrite(decl, base, foffset));
154 }
155 else if (type == char.class) {
156 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
157 ? new VarHandleChars.FieldStaticReadOnly(decl, base, foffset)
158 : new VarHandleChars.FieldStaticReadWrite(decl, base, foffset));
159 }
160 else if (type == int.class) {
161 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
162 ? new VarHandleInts.FieldStaticReadOnly(decl, base, foffset)
163 : new VarHandleInts.FieldStaticReadWrite(decl, base, foffset));
164 }
165 else if (type == long.class) {
166 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
167 ? new VarHandleLongs.FieldStaticReadOnly(decl, base, foffset)
168 : new VarHandleLongs.FieldStaticReadWrite(decl, base, foffset));
169 }
170 else if (type == float.class) {
171 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
172 ? new VarHandleFloats.FieldStaticReadOnly(decl, base, foffset)
173 : new VarHandleFloats.FieldStaticReadWrite(decl, base, foffset));
174 }
175 else if (type == double.class) {
176 return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
177 ? new VarHandleDoubles.FieldStaticReadOnly(decl, base, foffset)
178 : new VarHandleDoubles.FieldStaticReadWrite(decl, base, foffset));
179 }
180 else {
181 throw new UnsupportedOperationException();
182 }
183 }
184
185 // Required by instance field handles
186 static Field getFieldFromReceiverAndOffset(Class<?> receiverType,
187 long offset,
188 Class<?> fieldType) {
189 for (Field f : receiverType.getDeclaredFields()) {
190 if (Modifier.isStatic(f.getModifiers())) continue;
191
192 if (offset == UNSAFE.objectFieldOffset(f)) {
193 assert f.getType() == fieldType;
194 return f;
195 }
196 }
197 throw new InternalError("Field not found at offset");
198 }
199
200 // Required by instance static field handles
201 static Field getStaticFieldFromBaseAndOffset(Class<?> declaringClass,
202 long offset,
203 Class<?> fieldType) {
204 for (Field f : declaringClass.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 return maybeAdapt(UNSAFE.isFlatArray(arrayClass)
227 ? new VarHandleValues.Array(aoffset, ashift, arrayClass)
228 : new VarHandleReferences.Array(aoffset, ashift, arrayClass));
229 }
230 else if (componentType == boolean.class) {
231 return maybeAdapt(new VarHandleBooleans.Array(aoffset, ashift));
232 }
233 else if (componentType == byte.class) {
234 return maybeAdapt(new VarHandleBytes.Array(aoffset, ashift));
235 }
236 else if (componentType == short.class) {
237 return maybeAdapt(new VarHandleShorts.Array(aoffset, ashift));
238 }
239 else if (componentType == char.class) {
240 return maybeAdapt(new VarHandleChars.Array(aoffset, ashift));
241 }
242 else if (componentType == int.class) {
243 return maybeAdapt(new VarHandleInts.Array(aoffset, ashift));
244 }
245 else if (componentType == long.class) {
246 return maybeAdapt(new VarHandleLongs.Array(aoffset, ashift));
247 }
248 else if (componentType == float.class) {
249 return maybeAdapt(new VarHandleFloats.Array(aoffset, ashift));
250 }
251 else if (componentType == double.class) {
252 return maybeAdapt(new VarHandleDoubles.Array(aoffset, ashift));
253 }
254 else {
255 throw new UnsupportedOperationException();
256 }
257 }
258
259 static VarHandle byteArrayViewHandle(Class<?> viewArrayClass,
260 boolean be) {
261 if (!viewArrayClass.isArray())
262 throw new IllegalArgumentException("not an array: " + viewArrayClass);
263
264 Class<?> viewComponentType = viewArrayClass.getComponentType();
265
266 if (viewComponentType == long.class) {
267 return maybeAdapt(new VarHandleByteArrayAsLongs.ArrayHandle(be));
268 }
269 else if (viewComponentType == int.class) {
270 return maybeAdapt(new VarHandleByteArrayAsInts.ArrayHandle(be));
271 }
272 else if (viewComponentType == short.class) {
273 return maybeAdapt(new VarHandleByteArrayAsShorts.ArrayHandle(be));
274 }
275 else if (viewComponentType == char.class) {
276 return maybeAdapt(new VarHandleByteArrayAsChars.ArrayHandle(be));
277 }
278 else if (viewComponentType == double.class) {
279 return maybeAdapt(new VarHandleByteArrayAsDoubles.ArrayHandle(be));
280 }
281 else if (viewComponentType == float.class) {
282 return maybeAdapt(new VarHandleByteArrayAsFloats.ArrayHandle(be));
283 }
284
285 throw new UnsupportedOperationException();
286 }
287
288 static VarHandle makeByteBufferViewHandle(Class<?> viewArrayClass,
289 boolean be) {
290 if (!viewArrayClass.isArray())
291 throw new IllegalArgumentException("not an array: " + viewArrayClass);
292
293 Class<?> viewComponentType = viewArrayClass.getComponentType();
294
295 if (viewComponentType == long.class) {
296 return maybeAdapt(new VarHandleByteArrayAsLongs.ByteBufferHandle(be));
297 }
298 else if (viewComponentType == int.class) {
299 return maybeAdapt(new VarHandleByteArrayAsInts.ByteBufferHandle(be));
300 }
301 else if (viewComponentType == short.class) {
302 return maybeAdapt(new VarHandleByteArrayAsShorts.ByteBufferHandle(be));
303 }
304 else if (viewComponentType == char.class) {
305 return maybeAdapt(new VarHandleByteArrayAsChars.ByteBufferHandle(be));
306 }
307 else if (viewComponentType == double.class) {
308 return maybeAdapt(new VarHandleByteArrayAsDoubles.ByteBufferHandle(be));
309 }
310 else if (viewComponentType == float.class) {
311 return maybeAdapt(new VarHandleByteArrayAsFloats.ByteBufferHandle(be));
312 }
313
314 throw new UnsupportedOperationException();
315 }
316
317 /**
318 * Creates a memory segment view var handle.
319 *
320 * The resulting var handle will take a memory segment as first argument (the segment to be dereferenced),
321 * and a {@code long} as second argument (the offset into the segment).
322 *
323 * @param carrier the Java carrier type.
324 * @param alignmentMask alignment requirement to be checked upon access. In bytes. Expressed as a mask.
325 * @param byteOrder the byte order.
326 * @return the created VarHandle.
327 */
328 static VarHandle memorySegmentViewHandle(Class<?> carrier, long alignmentMask,
329 ByteOrder byteOrder) {
330 if (!carrier.isPrimitive() || carrier == void.class || carrier == boolean.class) {
331 throw new IllegalArgumentException("Invalid carrier: " + carrier.getName());
332 }
333 long size = Utils.byteWidthOfPrimitive(carrier);
334 boolean be = byteOrder == ByteOrder.BIG_ENDIAN;
335 boolean exact = VAR_HANDLE_SEGMENT_FORCE_EXACT;
336
337 if (carrier == byte.class) {
338 return maybeAdapt(new VarHandleSegmentAsBytes(be, size, alignmentMask, exact));
339 } else if (carrier == char.class) {
340 return maybeAdapt(new VarHandleSegmentAsChars(be, size, alignmentMask, exact));
341 } else if (carrier == short.class) {
342 return maybeAdapt(new VarHandleSegmentAsShorts(be, size, alignmentMask, exact));
343 } else if (carrier == int.class) {
344 return maybeAdapt(new VarHandleSegmentAsInts(be, size, alignmentMask, exact));
345 } else if (carrier == float.class) {
346 return maybeAdapt(new VarHandleSegmentAsFloats(be, size, alignmentMask, exact));
347 } else if (carrier == long.class) {
348 return maybeAdapt(new VarHandleSegmentAsLongs(be, size, alignmentMask, exact));
349 } else if (carrier == double.class) {
350 return maybeAdapt(new VarHandleSegmentAsDoubles(be, size, alignmentMask, exact));
351 } else {
352 throw new IllegalStateException("Cannot get here");
353 }
354 }
355
356 private static VarHandle maybeAdapt(VarHandle target) {
357 if (!VAR_HANDLE_IDENTITY_ADAPT) return target;
358 target = filterValue(target,
359 MethodHandles.identity(target.varType()), MethodHandles.identity(target.varType()));
360 MethodType mtype = target.accessModeType(VarHandle.AccessMode.GET);
361 for (int i = 0 ; i < mtype.parameterCount() ; i++) {
362 target = filterCoordinates(target, i, MethodHandles.identity(mtype.parameterType(i)));
363 }
364 return target;
365 }
366
367 public static VarHandle filterValue(VarHandle target, MethodHandle pFilterToTarget, MethodHandle pFilterFromTarget) {
368 Objects.requireNonNull(target);
369 Objects.requireNonNull(pFilterToTarget);
370 Objects.requireNonNull(pFilterFromTarget);
371 //check that from/to filters do not throw checked exceptions
372 MethodHandle filterToTarget = adaptForCheckedExceptions(pFilterToTarget);
373 MethodHandle filterFromTarget = adaptForCheckedExceptions(pFilterFromTarget);
374
375 List<Class<?>> newCoordinates = new ArrayList<>();
376 List<Class<?>> additionalCoordinates = new ArrayList<>();
377 newCoordinates.addAll(target.coordinateTypes());
378
379 //check that from/to filters have right signatures
380 if (filterFromTarget.type().parameterCount() != filterToTarget.type().parameterCount()) {
381 throw newIllegalArgumentException("filterFromTarget and filterToTarget have different arity", filterFromTarget.type(), filterToTarget.type());
382 } else if (filterFromTarget.type().parameterCount() < 1) {
383 throw newIllegalArgumentException("filterFromTarget filter type has wrong arity", filterFromTarget.type());
384 } else if (filterToTarget.type().parameterCount() < 1) {
385 throw newIllegalArgumentException("filterToTarget filter type has wrong arity", filterFromTarget.type());
386 } else if (filterFromTarget.type().lastParameterType() != filterToTarget.type().returnType() ||
387 filterToTarget.type().lastParameterType() != filterFromTarget.type().returnType()) {
388 throw newIllegalArgumentException("filterFromTarget and filterToTarget filter types do not match", filterFromTarget.type(), filterToTarget.type());
389 } else if (target.varType() != filterFromTarget.type().lastParameterType()) {
390 throw newIllegalArgumentException("filterFromTarget filter type does not match target var handle type", filterFromTarget.type(), target.varType());
391 } else if (target.varType() != filterToTarget.type().returnType()) {
392 throw newIllegalArgumentException("filterFromTarget filter type does not match target var handle type", filterToTarget.type(), target.varType());
393 } else if (filterFromTarget.type().parameterCount() > 1) {
394 for (int i = 0 ; i < filterFromTarget.type().parameterCount() - 1 ; i++) {
395 if (filterFromTarget.type().parameterType(i) != filterToTarget.type().parameterType(i)) {
396 throw newIllegalArgumentException("filterFromTarget and filterToTarget filter types do not match", filterFromTarget.type(), filterToTarget.type());
397 } else {
398 newCoordinates.add(filterFromTarget.type().parameterType(i));
399 additionalCoordinates.add((filterFromTarget.type().parameterType(i)));
400 }
401 }
402 }
403
404 return new IndirectVarHandle(target, filterFromTarget.type().returnType(), newCoordinates.toArray(new Class<?>[0]),
405 (mode, modeHandle) -> {
406 int lastParameterPos = modeHandle.type().parameterCount() - 1;
407 return switch (mode.at) {
408 case GET -> MethodHandles.collectReturnValue(modeHandle, filterFromTarget);
409 case SET -> MethodHandles.collectArguments(modeHandle, lastParameterPos, filterToTarget);
410 case GET_AND_UPDATE -> {
411 MethodHandle adapter = MethodHandles.collectReturnValue(modeHandle, filterFromTarget);
412 MethodHandle res = MethodHandles.collectArguments(adapter, lastParameterPos, filterToTarget);
413 if (additionalCoordinates.size() > 0) {
414 res = joinDuplicateArgs(res, lastParameterPos,
415 lastParameterPos + additionalCoordinates.size() + 1,
416 additionalCoordinates.size());
417 }
418 yield res;
419 }
420 case COMPARE_AND_EXCHANGE -> {
421 MethodHandle adapter = MethodHandles.collectReturnValue(modeHandle, filterFromTarget);
422 adapter = MethodHandles.collectArguments(adapter, lastParameterPos, filterToTarget);
423 if (additionalCoordinates.size() > 0) {
424 adapter = joinDuplicateArgs(adapter, lastParameterPos,
425 lastParameterPos + additionalCoordinates.size() + 1,
426 additionalCoordinates.size());
427 }
428 MethodHandle res = MethodHandles.collectArguments(adapter, lastParameterPos - 1, filterToTarget);
429 if (additionalCoordinates.size() > 0) {
430 res = joinDuplicateArgs(res, lastParameterPos - 1,
431 lastParameterPos + additionalCoordinates.size(),
432 additionalCoordinates.size());
433 }
434 yield res;
435 }
436 case COMPARE_AND_SET -> {
437 MethodHandle adapter = MethodHandles.collectArguments(modeHandle, lastParameterPos, filterToTarget);
438 MethodHandle res = MethodHandles.collectArguments(adapter, lastParameterPos - 1, filterToTarget);
439 if (additionalCoordinates.size() > 0) {
440 res = joinDuplicateArgs(res, lastParameterPos - 1,
441 lastParameterPos + additionalCoordinates.size(),
442 additionalCoordinates.size());
443 }
444 yield res;
445 }
446 };
447 });
448 }
449
450 private static MethodHandle joinDuplicateArgs(MethodHandle handle, int originalStart, int dropStart, int length) {
451 int[] perms = new int[handle.type().parameterCount()];
452 for (int i = 0 ; i < dropStart; i++) {
453 perms[i] = i;
454 }
455 for (int i = 0 ; i < length ; i++) {
456 perms[dropStart + i] = originalStart + i;
457 }
458 for (int i = dropStart + length ; i < perms.length ; i++) {
459 perms[i] = i - length;
460 }
461 return MethodHandles.permuteArguments(handle,
462 handle.type().dropParameterTypes(dropStart, dropStart + length),
463 perms);
464 }
465
466 public static VarHandle filterCoordinates(VarHandle target, int pos, MethodHandle... filters) {
467 Objects.requireNonNull(target);
468 Objects.requireNonNull(filters);
469
470 List<Class<?>> targetCoordinates = target.coordinateTypes();
471 if (pos < 0 || pos >= targetCoordinates.size()) {
472 throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
473 } else if (pos + filters.length > targetCoordinates.size()) {
474 throw new IllegalArgumentException("Too many filters");
475 }
476
477 if (filters.length == 0) return target;
478
479 List<Class<?>> newCoordinates = new ArrayList<>(targetCoordinates);
480 for (int i = 0 ; i < filters.length ; i++) {
481 MethodHandle filter = Objects.requireNonNull(filters[i]);
482 filter = adaptForCheckedExceptions(filter);
483 MethodType filterType = filter.type();
484 if (filterType.parameterCount() != 1) {
485 throw newIllegalArgumentException("Invalid filter type " + filterType);
486 } else if (newCoordinates.get(pos + i) != filterType.returnType()) {
487 throw newIllegalArgumentException("Invalid filter type " + filterType + " for coordinate type " + newCoordinates.get(i));
488 }
489 newCoordinates.set(pos + i, filters[i].type().parameterType(0));
490 }
491
492 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
493 (mode, modeHandle) -> MethodHandles.filterArguments(modeHandle, 1 + pos, filters));
494 }
495
496 public static VarHandle insertCoordinates(VarHandle target, int pos, Object... values) {
497 Objects.requireNonNull(target);
498 Objects.requireNonNull(values);
499
500 List<Class<?>> targetCoordinates = target.coordinateTypes();
501 if (pos < 0 || pos >= targetCoordinates.size()) {
502 throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
503 } else if (pos + values.length > targetCoordinates.size()) {
504 throw new IllegalArgumentException("Too many values");
505 }
506
507 if (values.length == 0) return target;
508
509 List<Class<?>> newCoordinates = new ArrayList<>(targetCoordinates);
510 for (int i = 0 ; i < values.length ; i++) {
511 Class<?> pt = newCoordinates.get(pos);
512 if (pt.isPrimitive()) {
513 Wrapper w = Wrapper.forPrimitiveType(pt);
514 w.convert(values[i], pt);
515 } else {
516 pt.cast(values[i]);
517 }
518 newCoordinates.remove(pos);
519 }
520
521 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
522 (mode, modeHandle) -> MethodHandles.insertArguments(modeHandle, 1 + pos, values));
523 }
524
525 public static VarHandle permuteCoordinates(VarHandle target, List<Class<?>> newCoordinates, int... reorder) {
526 Objects.requireNonNull(target);
527 Objects.requireNonNull(newCoordinates);
528 Objects.requireNonNull(reorder);
529
530 List<Class<?>> targetCoordinates = target.coordinateTypes();
531 MethodHandles.permuteArgumentChecks(reorder,
532 MethodType.methodType(void.class, newCoordinates),
533 MethodType.methodType(void.class, targetCoordinates));
534
535 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
536 (mode, modeHandle) ->
537 MethodHandles.permuteArguments(modeHandle,
538 methodTypeFor(mode.at, modeHandle.type(), targetCoordinates, newCoordinates),
539 reorderArrayFor(mode.at, newCoordinates, reorder)));
540 }
541
542 private static int numTrailingArgs(VarHandle.AccessType at) {
543 return switch (at) {
544 case GET -> 0;
545 case GET_AND_UPDATE, SET -> 1;
546 case COMPARE_AND_SET, COMPARE_AND_EXCHANGE -> 2;
547 };
548 }
549
550 private static int[] reorderArrayFor(VarHandle.AccessType at, List<Class<?>> newCoordinates, int[] reorder) {
551 int numTrailingArgs = numTrailingArgs(at);
552 int[] adjustedReorder = new int[reorder.length + 1 + numTrailingArgs];
553 adjustedReorder[0] = 0;
554 for (int i = 0 ; i < reorder.length ; i++) {
555 adjustedReorder[i + 1] = reorder[i] + 1;
556 }
557 for (int i = 0 ; i < numTrailingArgs ; i++) {
558 adjustedReorder[i + reorder.length + 1] = i + newCoordinates.size() + 1;
559 }
560 return adjustedReorder;
561 }
562
563 private static MethodType methodTypeFor(VarHandle.AccessType at, MethodType oldType, List<Class<?>> oldCoordinates, List<Class<?>> newCoordinates) {
564 int numTrailingArgs = numTrailingArgs(at);
565 MethodType adjustedType = MethodType.methodType(oldType.returnType(), oldType.parameterType(0));
566 adjustedType = adjustedType.appendParameterTypes(newCoordinates);
567 for (int i = 0 ; i < numTrailingArgs ; i++) {
568 adjustedType = adjustedType.appendParameterTypes(oldType.parameterType(1 + oldCoordinates.size() + i));
569 }
570 return adjustedType;
571 }
572
573 public static VarHandle collectCoordinates(VarHandle target, int pos, MethodHandle pFilter) {
574 Objects.requireNonNull(target);
575 Objects.requireNonNull(pFilter);
576 MethodHandle filter = adaptForCheckedExceptions(pFilter);
577
578 List<Class<?>> targetCoordinates = target.coordinateTypes();
579 if (pos < 0 || pos >= targetCoordinates.size()) {
580 throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
581 } else if (filter.type().returnType() != void.class && filter.type().returnType() != targetCoordinates.get(pos)) {
582 throw newIllegalArgumentException("Invalid filter type " + filter.type() + " for coordinate type " + targetCoordinates.get(pos));
583 }
584
585 List<Class<?>> newCoordinates = new ArrayList<>(targetCoordinates);
586 if (filter.type().returnType() != void.class) {
587 newCoordinates.remove(pos);
588 }
589 newCoordinates.addAll(pos, filter.type().parameterList());
590
591 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
592 (mode, modeHandle) -> MethodHandles.collectArguments(modeHandle, 1 + pos, filter));
593 }
594
595 public static VarHandle dropCoordinates(VarHandle target, int pos, Class<?>... valueTypes) {
596 Objects.requireNonNull(target);
597 Objects.requireNonNull(valueTypes);
598
599 List<Class<?>> targetCoordinates = target.coordinateTypes();
600 if (pos < 0 || pos > targetCoordinates.size()) {
601 throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
602 }
603
604 if (valueTypes.length == 0) return target;
605
606 List<Class<?>> newCoordinates = new ArrayList<>(targetCoordinates);
607 newCoordinates.addAll(pos, List.of(valueTypes));
608
609 return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class<?>[0]),
610 (mode, modeHandle) -> MethodHandles.dropArguments(modeHandle, 1 + pos, valueTypes));
611 }
612
613 private static MethodHandle adaptForCheckedExceptions(MethodHandle target) {
614 Class<?>[] exceptionTypes = exceptionTypes(target);
615 if (exceptionTypes != null) { // exceptions known
616 if (Stream.of(exceptionTypes).anyMatch(VarHandles::isCheckedException)) {
617 throw newIllegalArgumentException("Cannot adapt a var handle with a method handle which throws checked exceptions");
618 }
619 return target; // no adaptation needed
620 } else {
621 MethodHandle handler = MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_VarHandles_handleCheckedExceptions);
622 MethodHandle zero = MethodHandles.zero(target.type().returnType()); // dead branch
623 handler = MethodHandles.collectArguments(zero, 0, handler);
624 return MethodHandles.catchException(target, Throwable.class, handler);
625 }
626 }
627
628 static void handleCheckedExceptions(Throwable throwable) throws Throwable {
629 if (isCheckedException(throwable.getClass())) {
630 throw new IllegalStateException("Adapter handle threw checked exception", throwable);
631 }
632 throw throwable;
633 }
634
635 static Class<?>[] exceptionTypes(MethodHandle handle) {
636 if (handle instanceof DirectMethodHandle directHandle) {
637 byte refKind = directHandle.member.getReferenceKind();
638 MethodHandleInfo info = new InfoFromMemberName(
639 MethodHandles.Lookup.IMPL_LOOKUP,
640 directHandle.member,
641 refKind);
642 if (MethodHandleNatives.refKindIsMethod(refKind)) {
643 return info.reflectAs(Method.class, MethodHandles.Lookup.IMPL_LOOKUP)
644 .getExceptionTypes();
645 } else if (MethodHandleNatives.refKindIsField(refKind)) {
646 return new Class<?>[0];
647 } else if (MethodHandleNatives.refKindIsConstructor(refKind)) {
648 return info.reflectAs(Constructor.class, MethodHandles.Lookup.IMPL_LOOKUP)
649 .getExceptionTypes();
650 } else {
651 throw new AssertionError("Cannot get here");
652 }
653 } else if (handle instanceof DelegatingMethodHandle delegatingMh) {
654 return exceptionTypes(delegatingMh.getTarget());
655 } else if (handle instanceof NativeMethodHandle) {
656 return new Class<?>[0];
657 }
658
659 assert handle instanceof BoundMethodHandle : "Unexpected handle type: " + handle;
660 // unknown
661 return null;
662 }
663
664 private static boolean isCheckedException(Class<?> clazz) {
665 return Throwable.class.isAssignableFrom(clazz) &&
666 !RuntimeException.class.isAssignableFrom(clazz) &&
667 !Error.class.isAssignableFrom(clazz);
668 }
669
670 // /**
671 // * A helper program to generate the VarHandleGuards class with a set of
672 // * static guard methods each of which corresponds to a particular shape and
673 // * performs a type check of the symbolic type descriptor with the VarHandle
674 // * type descriptor before linking/invoking to the underlying operation as
675 // * characterized by the operation member name on the VarForm of the
676 // * VarHandle.
677 // * <p>
678 // * The generated class essentially encapsulates pre-compiled LambdaForms,
679 // * one for each method, for the most set of common method signatures.
680 // * This reduces static initialization costs, footprint costs, and circular
681 // * dependencies that may arise if a class is generated per LambdaForm.
682 // * <p>
683 // * A maximum of L*T*S methods will be generated where L is the number of
684 // * access modes kinds (or unique operation signatures) and T is the number
685 // * of variable types and S is the number of shapes (such as instance field,
686 // * static field, or array access).
687 // * If there are 4 unique operation signatures, 5 basic types (Object, int,
688 // * long, float, double), and 3 shapes then a maximum of 60 methods will be
689 // * generated. However, the number is likely to be less since there
690 // * be duplicate signatures.
691 // * <p>
692 // * Each method is annotated with @LambdaForm.Compiled to inform the runtime
693 // * that such methods should be treated as if a method of a class that is the
694 // * result of compiling a LambdaForm. Annotation of such methods is
695 // * important for correct evaluation of certain assertions and method return
696 // * type profiling in HotSpot.
697 // */
698 // public static class GuardMethodGenerator {
699 //
700 // static final String GUARD_METHOD_SIG_TEMPLATE = "<RETURN> <NAME>_<SIGNATURE>(<PARAMS>)";
701 //
702 // static final String GUARD_METHOD_TEMPLATE =
703 // """
704 // @ForceInline
705 // @LambdaForm.Compiled
706 // @Hidden
707 // static final <METHOD> throws Throwable {
708 // boolean direct = handle.checkAccessModeThenIsDirect(ad);
709 // if (direct && handle.vform.methodType_table[ad.type] == ad.symbolicMethodTypeErased) {
710 // <RESULT_ERASED>MethodHandle.linkToStatic(<LINK_TO_STATIC_ARGS>);<RETURN_ERASED>
711 // } else {
712 // MethodHandle mh = handle.getMethodHandle(ad.mode);
713 // <RETURN>mh.asType(ad.symbolicMethodTypeInvoker).invokeBasic(<LINK_TO_INVOKER_ARGS>);
714 // }
715 // }""";
716 //
717 // static final String GUARD_METHOD_TEMPLATE_V =
718 // """
719 // @ForceInline
720 // @LambdaForm.Compiled
721 // @Hidden
722 // static final <METHOD> throws Throwable {
723 // boolean direct = handle.checkAccessModeThenIsDirect(ad);
724 // if (direct && handle.vform.methodType_table[ad.type] == ad.symbolicMethodTypeErased) {
725 // MethodHandle.linkToStatic(<LINK_TO_STATIC_ARGS>);
726 // } else if (direct && handle.vform.getMethodType_V(ad.type) == ad.symbolicMethodTypeErased) {
727 // MethodHandle.linkToStatic(<LINK_TO_STATIC_ARGS>);
728 // } else {
729 // MethodHandle mh = handle.getMethodHandle(ad.mode);
730 // mh.asType(ad.symbolicMethodTypeInvoker).invokeBasic(<LINK_TO_INVOKER_ARGS>);
731 // }
732 // }""";
733 //
734 // // A template for deriving the operations
735 // // could be supported by annotating VarHandle directly with the
736 // // operation kind and shape
737 // interface VarHandleTemplate {
738 // Object get();
739 //
740 // void set(Object value);
741 //
742 // boolean compareAndSet(Object actualValue, Object expectedValue);
743 //
744 // Object compareAndExchange(Object actualValue, Object expectedValue);
745 //
746 // Object getAndUpdate(Object value);
747 // }
748 //
749 // record HandleType(Class<?> receiver, Class<?> value, Class<?>... intermediates) {
750 // }
751 //
752 // /**
753 // * @param args parameters
754 // */
755 // public static void main(String[] args) {
756 // System.out.println("package java.lang.invoke;");
757 // System.out.println();
758 // System.out.println("import jdk.internal.vm.annotation.ForceInline;");
759 // System.out.println("import jdk.internal.vm.annotation.Hidden;");
760 // System.out.println();
761 // System.out.println("// This class is auto-generated by " +
762 // GuardMethodGenerator.class.getName() +
763 // ". Do not edit.");
764 // System.out.println("final class VarHandleGuards {");
765 //
766 // System.out.println();
767 //
768 // // Declare the stream of shapes
769 // Stream<HandleType> hts = Stream.of(
770 // // Object->Object
771 // new HandleType(Object.class, Object.class),
772 // // Object->int
773 // new HandleType(Object.class, int.class),
774 // // Object->long
775 // new HandleType(Object.class, long.class),
776 // // Object->float
777 // new HandleType(Object.class, float.class),
778 // // Object->double
779 // new HandleType(Object.class, double.class),
780 //
781 // // <static>->Object
782 // new HandleType(null, Object.class),
783 // // <static>->int
784 // new HandleType(null, int.class),
785 // // <static>->long
786 // new HandleType(null, long.class),
787 // // <static>->float
788 // new HandleType(null, float.class),
789 // // <static>->double
790 // new HandleType(null, double.class),
791 //
792 // // Array[int]->Object
793 // new HandleType(Object.class, Object.class, int.class),
794 // // Array[int]->int
795 // new HandleType(Object.class, int.class, int.class),
796 // // Array[int]->long
797 // new HandleType(Object.class, long.class, int.class),
798 // // Array[int]->float
799 // new HandleType(Object.class, float.class, int.class),
800 // // Array[int]->double
801 // new HandleType(Object.class, double.class, int.class),
802 //
803 // // Array[long]->int
804 // new HandleType(Object.class, int.class, long.class),
805 // // Array[long]->long
806 // new HandleType(Object.class, long.class, long.class)
807 // );
808 //
809 // hts.flatMap(ht -> Stream.of(VarHandleTemplate.class.getMethods()).
810 // map(m -> generateMethodType(m, ht.receiver, ht.value, ht.intermediates))).
811 // distinct().
812 // map(GuardMethodGenerator::generateMethod).
813 // forEach(System.out::println);
814 //
815 // System.out.println("}");
816 // }
817 //
818 // static MethodType generateMethodType(Method m, Class<?> receiver, Class<?> value, Class<?>... intermediates) {
819 // Class<?> returnType = m.getReturnType() == Object.class
820 // ? value : m.getReturnType();
821 //
822 // List<Class<?>> params = new ArrayList<>();
823 // if (receiver != null)
824 // params.add(receiver);
825 // java.util.Collections.addAll(params, intermediates);
826 // for (var p : m.getParameters()) {
827 // params.add(value);
828 // }
829 // return MethodType.methodType(returnType, params);
830 // }
831 //
832 // static String generateMethod(MethodType mt) {
833 // Class<?> returnType = mt.returnType();
834 //
835 // var params = new java.util.LinkedHashMap<String, Class<?>>();
836 // params.put("handle", VarHandle.class);
837 // for (int i = 0; i < mt.parameterCount(); i++) {
838 // params.put("arg" + i, mt.parameterType(i));
839 // }
840 // params.put("ad", VarHandle.AccessDescriptor.class);
841 //
842 // // Generate method signature line
843 // String RETURN = className(returnType);
844 // String NAME = "guard";
845 // String SIGNATURE = getSignature(mt);
846 // String PARAMS = params.entrySet().stream().
847 // map(e -> className(e.getValue()) + " " + e.getKey()).
848 // collect(java.util.stream.Collectors.joining(", "));
849 // String METHOD = GUARD_METHOD_SIG_TEMPLATE.
850 // replace("<RETURN>", RETURN).
851 // replace("<NAME>", NAME).
852 // replace("<SIGNATURE>", SIGNATURE).
853 // replace("<PARAMS>", PARAMS);
854 //
855 // // Generate method
856 // params.remove("ad");
857 //
858 // List<String> LINK_TO_STATIC_ARGS = new ArrayList<>(params.keySet());
859 // LINK_TO_STATIC_ARGS.add("handle.vform.getMemberName(ad.mode)");
860 //
861 // List<String> LINK_TO_INVOKER_ARGS = new ArrayList<>(params.keySet());
862 // LINK_TO_INVOKER_ARGS.set(0, LINK_TO_INVOKER_ARGS.get(0) + ".asDirect()");
863 //
864 // RETURN = returnType == void.class
865 // ? ""
866 // : returnType == Object.class
867 // ? "return "
868 // : "return (" + returnType.getName() + ") ";
869 //
870 // String RESULT_ERASED = returnType == void.class
871 // ? ""
872 // : returnType != Object.class
873 // ? "return (" + returnType.getName() + ") "
874 // : "Object r = ";
875 //
876 // String RETURN_ERASED = returnType != Object.class
877 // ? ""
878 // : "\n return ad.returnType.cast(r);";
879 //
880 // String template = returnType == void.class
881 // ? GUARD_METHOD_TEMPLATE_V
882 // : GUARD_METHOD_TEMPLATE;
883 // return template.
884 // replace("<METHOD>", METHOD).
885 // replace("<NAME>", NAME).
886 // replaceAll("<RETURN>", RETURN).
887 // replace("<RESULT_ERASED>", RESULT_ERASED).
888 // replace("<RETURN_ERASED>", RETURN_ERASED).
889 // replaceAll("<LINK_TO_STATIC_ARGS>", String.join(", ", LINK_TO_STATIC_ARGS)).
890 // replace("<LINK_TO_INVOKER_ARGS>", String.join(", ", LINK_TO_INVOKER_ARGS))
891 // .indent(4);
892 // }
893 //
894 // static String className(Class<?> c) {
895 // String n = c.getName();
896 // if (n.startsWith("java.lang.")) {
897 // n = n.replace("java.lang.", "");
898 // if (n.startsWith("invoke.")) {
899 // n = n.replace("invoke.", "");
900 // }
901 // }
902 // return n.replace('$', '.');
903 // }
904 //
905 // static String getSignature(MethodType m) {
906 // StringBuilder sb = new StringBuilder(m.parameterCount() + 1);
907 //
908 // for (int i = 0; i < m.parameterCount(); i++) {
909 // Class<?> pt = m.parameterType(i);
910 // sb.append(getCharType(pt));
911 // }
912 //
913 // sb.append('_').append(getCharType(m.returnType()));
914 //
915 // return sb.toString();
916 // }
917 //
918 // static char getCharType(Class<?> pt) {
919 // return Wrapper.forBasicType(pt).basicTypeChar();
920 // }
921 // }
922 }