1 /*
2 * Copyright (c) 2008, 2013, 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 java.security.AccessController;
29 import java.security.PrivilegedAction;
30 import java.util.ArrayList;
31 import java.util.Arrays;
32 import java.util.Collections;
33 import java.util.List;
34
35 import sun.invoke.empty.Empty;
36 import sun.invoke.util.ValueConversions;
37 import sun.invoke.util.VerifyType;
38 import sun.invoke.util.Wrapper;
39 import sun.reflect.CallerSensitive;
40 import sun.reflect.Reflection;
41 import static java.lang.invoke.LambdaForm.*;
42 import static java.lang.invoke.MethodHandleStatics.*;
43 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
44
45 /**
46 * Trusted implementation code for MethodHandle.
47 * @author jrose
48 */
49 /*non-public*/ abstract class MethodHandleImpl {
50 // Do not adjust this except for special platforms:
51 private static final int MAX_ARITY;
52 static {
53 final Object[] values = { 255 };
54 AccessController.doPrivileged(new PrivilegedAction<Void>() {
55 @Override
56 public Void run() {
57 values[0] = Integer.getInteger(MethodHandleImpl.class.getName()+".MAX_ARITY", 255);
58 return null;
59 }
60 });
61 MAX_ARITY = (Integer) values[0];
62 }
63
64 /// Factory methods to create method handles:
65
66 static void initStatics() {
67 // Trigger selected static initializations.
68 MemberName.Factory.INSTANCE.getClass();
69 }
70
71 static MethodHandle makeArrayElementAccessor(Class<?> arrayClass, boolean isSetter) {
72 if (arrayClass == Object[].class)
73 return (isSetter ? ArrayAccessor.OBJECT_ARRAY_SETTER : ArrayAccessor.OBJECT_ARRAY_GETTER);
74 if (!arrayClass.isArray())
75 throw newIllegalArgumentException("not an array: "+arrayClass);
76 MethodHandle[] cache = ArrayAccessor.TYPED_ACCESSORS.get(arrayClass);
77 int cacheIndex = (isSetter ? ArrayAccessor.SETTER_INDEX : ArrayAccessor.GETTER_INDEX);
78 MethodHandle mh = cache[cacheIndex];
79 if (mh != null) return mh;
80 mh = ArrayAccessor.getAccessor(arrayClass, isSetter);
81 MethodType correctType = ArrayAccessor.correctType(arrayClass, isSetter);
82 if (mh.type() != correctType) {
83 assert(mh.type().parameterType(0) == Object[].class);
84 assert((isSetter ? mh.type().parameterType(2) : mh.type().returnType()) == Object.class);
85 assert(isSetter || correctType.parameterType(0).getComponentType() == correctType.returnType());
86 // safe to view non-strictly, because element type follows from array type
87 mh = mh.viewAsType(correctType);
88 }
89 // Atomically update accessor cache.
90 synchronized(cache) {
91 if (cache[cacheIndex] == null) {
92 cache[cacheIndex] = mh;
93 } else {
94 // Throw away newly constructed accessor and use cached version.
95 mh = cache[cacheIndex];
96 }
97 }
98 return mh;
99 }
100
101 static final class ArrayAccessor {
102 /// Support for array element access
103 static final int GETTER_INDEX = 0, SETTER_INDEX = 1, INDEX_LIMIT = 2;
104 static final ClassValue<MethodHandle[]> TYPED_ACCESSORS
105 = new ClassValue<MethodHandle[]>() {
106 @Override
107 protected MethodHandle[] computeValue(Class<?> type) {
108 return new MethodHandle[INDEX_LIMIT];
109 }
110 };
111 static final MethodHandle OBJECT_ARRAY_GETTER, OBJECT_ARRAY_SETTER;
112 static {
113 MethodHandle[] cache = TYPED_ACCESSORS.get(Object[].class);
114 cache[GETTER_INDEX] = OBJECT_ARRAY_GETTER = getAccessor(Object[].class, false);
115 cache[SETTER_INDEX] = OBJECT_ARRAY_SETTER = getAccessor(Object[].class, true);
116
117 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_GETTER.internalMemberName()));
118 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_SETTER.internalMemberName()));
119 }
120
121 static int getElementI(int[] a, int i) { return a[i]; }
122 static long getElementJ(long[] a, int i) { return a[i]; }
123 static float getElementF(float[] a, int i) { return a[i]; }
124 static double getElementD(double[] a, int i) { return a[i]; }
125 static boolean getElementZ(boolean[] a, int i) { return a[i]; }
126 static byte getElementB(byte[] a, int i) { return a[i]; }
127 static short getElementS(short[] a, int i) { return a[i]; }
128 static char getElementC(char[] a, int i) { return a[i]; }
129 static Object getElementL(Object[] a, int i) { return a[i]; }
130
131 static void setElementI(int[] a, int i, int x) { a[i] = x; }
132 static void setElementJ(long[] a, int i, long x) { a[i] = x; }
133 static void setElementF(float[] a, int i, float x) { a[i] = x; }
134 static void setElementD(double[] a, int i, double x) { a[i] = x; }
135 static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; }
136 static void setElementB(byte[] a, int i, byte x) { a[i] = x; }
137 static void setElementS(short[] a, int i, short x) { a[i] = x; }
138 static void setElementC(char[] a, int i, char x) { a[i] = x; }
139 static void setElementL(Object[] a, int i, Object x) { a[i] = x; }
140
141 static String name(Class<?> arrayClass, boolean isSetter) {
142 Class<?> elemClass = arrayClass.getComponentType();
143 if (elemClass == null) throw newIllegalArgumentException("not an array", arrayClass);
144 return (!isSetter ? "getElement" : "setElement") + Wrapper.basicTypeChar(elemClass);
145 }
146 static MethodType type(Class<?> arrayClass, boolean isSetter) {
147 Class<?> elemClass = arrayClass.getComponentType();
148 Class<?> arrayArgClass = arrayClass;
149 if (!elemClass.isPrimitive()) {
150 arrayArgClass = Object[].class;
151 elemClass = Object.class;
152 }
153 return !isSetter ?
154 MethodType.methodType(elemClass, arrayArgClass, int.class) :
155 MethodType.methodType(void.class, arrayArgClass, int.class, elemClass);
156 }
157 static MethodType correctType(Class<?> arrayClass, boolean isSetter) {
158 Class<?> elemClass = arrayClass.getComponentType();
159 return !isSetter ?
160 MethodType.methodType(elemClass, arrayClass, int.class) :
161 MethodType.methodType(void.class, arrayClass, int.class, elemClass);
162 }
163 static MethodHandle getAccessor(Class<?> arrayClass, boolean isSetter) {
164 String name = name(arrayClass, isSetter);
165 MethodType type = type(arrayClass, isSetter);
166 try {
167 return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type);
168 } catch (ReflectiveOperationException ex) {
169 throw uncaughtException(ex);
170 }
171 }
172 }
173
174 /**
175 * Create a JVM-level adapter method handle to conform the given method
176 * handle to the similar newType, using only pairwise argument conversions.
177 * For each argument, convert incoming argument to the exact type needed.
178 * The argument conversions allowed are casting, boxing and unboxing,
179 * integral widening or narrowing, and floating point widening or narrowing.
180 * @param srcType required call type
181 * @param target original method handle
182 * @param level which strength of conversion is allowed
183 * @return an adapter to the original handle with the desired new type,
184 * or the original target if the types are already identical
185 * or null if the adaptation cannot be made
186 */
187 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType, int level) {
188 assert(level >= 0 && level <= 2);
189 MethodType dstType = target.type();
190 assert(dstType.parameterCount() == target.type().parameterCount());
191 if (srcType == dstType)
192 return target;
193
194 // Calculate extra arguments (temporaries) required in the names array.
195 // FIXME: Use an ArrayList<Name>. Some arguments require more than one conversion step.
196 final int INARG_COUNT = srcType.parameterCount();
197 int conversions = 0;
198 boolean[] needConv = new boolean[1+INARG_COUNT];
199 for (int i = 0; i <= INARG_COUNT; i++) {
200 Class<?> src = (i == INARG_COUNT) ? dstType.returnType() : srcType.parameterType(i);
201 Class<?> dst = (i == INARG_COUNT) ? srcType.returnType() : dstType.parameterType(i);
202 if (!VerifyType.isNullConversion(src, dst, false) ||
203 level <= 1 && dst.isInterface() && !dst.isAssignableFrom(src)) {
204 needConv[i] = true;
205 conversions++;
206 }
207 }
208 boolean retConv = needConv[INARG_COUNT];
209 if (retConv && srcType.returnType() == void.class) {
210 retConv = false;
211 conversions--;
212 }
213
214 final int IN_MH = 0;
215 final int INARG_BASE = 1;
216 final int INARG_LIMIT = INARG_BASE + INARG_COUNT;
217 final int NAME_LIMIT = INARG_LIMIT + conversions + 1;
218 final int RETURN_CONV = (!retConv ? -1 : NAME_LIMIT - 1);
219 final int OUT_CALL = (!retConv ? NAME_LIMIT : RETURN_CONV) - 1;
220 final int RESULT = (srcType.returnType() == void.class ? -1 : NAME_LIMIT - 1);
221
222 // Now build a LambdaForm.
223 MethodType lambdaType = srcType.basicType().invokerType();
224 Name[] names = arguments(NAME_LIMIT - INARG_LIMIT, lambdaType);
225
226 // Collect the arguments to the outgoing call, maybe with conversions:
227 final int OUTARG_BASE = 0; // target MH is Name.function, name Name.arguments[0]
228 Object[] outArgs = new Object[OUTARG_BASE + INARG_COUNT];
229
230 int nameCursor = INARG_LIMIT;
231 for (int i = 0; i < INARG_COUNT; i++) {
232 Class<?> src = srcType.parameterType(i);
233 Class<?> dst = dstType.parameterType(i);
234
235 if (!needConv[i]) {
236 // do nothing: difference is trivial
237 outArgs[OUTARG_BASE + i] = names[INARG_BASE + i];
238 continue;
239 }
240
241 // Tricky case analysis follows.
242 MethodHandle fn = null;
243 if (src.isPrimitive()) {
244 if (dst.isPrimitive()) {
245 fn = ValueConversions.convertPrimitive(src, dst);
246 } else {
247 Wrapper w = Wrapper.forPrimitiveType(src);
248 MethodHandle boxMethod = ValueConversions.box(w);
249 if (dst == w.wrapperType())
250 fn = boxMethod;
251 else
252 fn = boxMethod.asType(MethodType.methodType(dst, src));
253 }
254 } else {
255 if (dst.isPrimitive()) {
256 // Caller has boxed a primitive. Unbox it for the target.
257 Wrapper w = Wrapper.forPrimitiveType(dst);
258 if (level == 0 || VerifyType.isNullConversion(src, w.wrapperType(), false)) {
259 fn = ValueConversions.unbox(dst);
260 } else if (src == Object.class || !Wrapper.isWrapperType(src)) {
261 // Examples: Object->int, Number->int, Comparable->int; Byte->int, Character->int
262 // must include additional conversions
263 // src must be examined at runtime, to detect Byte, Character, etc.
264 MethodHandle unboxMethod = (level == 1
265 ? ValueConversions.unbox(dst)
266 : ValueConversions.unboxCast(dst));
267 fn = unboxMethod;
268 } else {
269 // Example: Byte->int
270 // Do this by reformulating the problem to Byte->byte.
271 Class<?> srcPrim = Wrapper.forWrapperType(src).primitiveType();
272 MethodHandle unbox = ValueConversions.unbox(srcPrim);
273 // Compose the two conversions. FIXME: should make two Names for this job
274 fn = unbox.asType(MethodType.methodType(dst, src));
275 }
276 } else {
277 // Simple reference conversion.
278 // Note: Do not check for a class hierarchy relation
279 // between src and dst. In all cases a 'null' argument
280 // will pass the cast conversion.
281 fn = ValueConversions.cast(dst, Lazy.MH_castReference);
282 }
283 }
284 Name conv = new Name(fn, names[INARG_BASE + i]);
285 assert(names[nameCursor] == null);
286 names[nameCursor++] = conv;
287 assert(outArgs[OUTARG_BASE + i] == null);
288 outArgs[OUTARG_BASE + i] = conv;
289 }
290
291 // Build argument array for the call.
292 assert(nameCursor == OUT_CALL);
293 names[OUT_CALL] = new Name(target, outArgs);
294
295 if (RETURN_CONV < 0) {
296 assert(OUT_CALL == names.length-1);
297 } else {
298 Class<?> needReturn = srcType.returnType();
299 Class<?> haveReturn = dstType.returnType();
300 MethodHandle fn;
301 Object[] arg = { names[OUT_CALL] };
302 if (haveReturn == void.class) {
303 // synthesize a zero value for the given void
304 Object zero = Wrapper.forBasicType(needReturn).zero();
305 fn = MethodHandles.constant(needReturn, zero);
306 arg = new Object[0]; // don't pass names[OUT_CALL] to conversion
307 } else {
308 MethodHandle identity = MethodHandles.identity(needReturn);
309 MethodType needConversion = identity.type().changeParameterType(0, haveReturn);
310 fn = makePairwiseConvert(identity, needConversion, level);
311 }
312 assert(names[RETURN_CONV] == null);
313 names[RETURN_CONV] = new Name(fn, arg);
314 assert(RETURN_CONV == names.length-1);
315 }
316
317 LambdaForm form = new LambdaForm("convert", lambdaType.parameterCount(), names, RESULT);
318 return SimpleMethodHandle.make(srcType, form);
319 }
320
321 /**
322 * Identity function, with reference cast.
323 * @param t an arbitrary reference type
324 * @param x an arbitrary reference value
325 * @return the same value x
326 */
327 @ForceInline
328 @SuppressWarnings("unchecked")
329 static <T,U> T castReference(Class<? extends T> t, U x) {
330 // inlined Class.cast because we can't ForceInline it
331 if (x != null && !t.isInstance(x))
332 throw newClassCastException(t, x);
333 return (T) x;
334 }
335
336 private static ClassCastException newClassCastException(Class<?> t, Object obj) {
337 return new ClassCastException("Cannot cast " + obj.getClass().getName() + " to " + t.getName());
338 }
339
340 static MethodHandle makeReferenceIdentity(Class<?> refType) {
341 MethodType lambdaType = MethodType.genericMethodType(1).invokerType();
342 Name[] names = arguments(1, lambdaType);
343 names[names.length - 1] = new Name(ValueConversions.identity(), names[1]);
344 LambdaForm form = new LambdaForm("identity", lambdaType.parameterCount(), names);
345 return SimpleMethodHandle.make(MethodType.methodType(refType, refType), form);
346 }
347
348 static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
349 MethodType type = target.type();
350 int last = type.parameterCount() - 1;
351 if (type.parameterType(last) != arrayType)
352 target = target.asType(type.changeParameterType(last, arrayType));
353 target = target.asFixedArity(); // make sure this attribute is turned off
354 return new AsVarargsCollector(target, target.type(), arrayType);
355 }
356
357 static class AsVarargsCollector extends MethodHandle {
358 private final MethodHandle target;
359 private final Class<?> arrayType;
360 private @Stable MethodHandle asCollectorCache;
361
362 AsVarargsCollector(MethodHandle target, MethodType type, Class<?> arrayType) {
363 super(type, reinvokerForm(target));
364 this.target = target;
365 this.arrayType = arrayType;
366 this.asCollectorCache = target.asCollector(arrayType, 0);
367 }
368
369 @Override MethodHandle reinvokerTarget() { return target; }
370
371 @Override
372 public boolean isVarargsCollector() {
373 return true;
374 }
375
376 @Override
377 public MethodHandle asFixedArity() {
378 return target;
379 }
380
381 @Override
382 public MethodHandle asTypeUncached(MethodType newType) {
383 MethodType type = this.type();
384 int collectArg = type.parameterCount() - 1;
385 int newArity = newType.parameterCount();
386 if (newArity == collectArg+1 &&
387 type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
388 // if arity and trailing parameter are compatible, do normal thing
389 return asTypeCache = asFixedArity().asType(newType);
390 }
391 // check cache
392 MethodHandle acc = asCollectorCache;
393 if (acc != null && acc.type().parameterCount() == newArity)
394 return asTypeCache = acc.asType(newType);
395 // build and cache a collector
396 int arrayLength = newArity - collectArg;
397 MethodHandle collector;
398 try {
399 collector = asFixedArity().asCollector(arrayType, arrayLength);
400 assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
401 } catch (IllegalArgumentException ex) {
402 throw new WrongMethodTypeException("cannot build collector", ex);
403 }
404 asCollectorCache = collector;
405 return asTypeCache = collector.asType(newType);
406 }
407
408 @Override
409 MethodHandle setVarargs(MemberName member) {
410 if (member.isVarargs()) return this;
411 return asFixedArity();
412 }
413
414 @Override
415 MethodHandle viewAsType(MethodType newType) {
416 if (newType.lastParameterType() != type().lastParameterType())
417 throw new InternalError();
418 MethodHandle newTarget = asFixedArity().viewAsType(newType);
419 // put back the varargs bit:
420 return new AsVarargsCollector(newTarget, newType, arrayType);
421 }
422
423 @Override
424 MemberName internalMemberName() {
425 return asFixedArity().internalMemberName();
426 }
427 @Override
428 Class<?> internalCallerClass() {
429 return asFixedArity().internalCallerClass();
430 }
431
432 /*non-public*/
433 @Override
434 boolean isInvokeSpecial() {
435 return asFixedArity().isInvokeSpecial();
436 }
437 }
438
439 /** Factory method: Spread selected argument. */
440 static MethodHandle makeSpreadArguments(MethodHandle target,
441 Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
442 MethodType targetType = target.type();
443
444 for (int i = 0; i < spreadArgCount; i++) {
445 Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i);
446 if (arg == null) arg = Object.class;
447 targetType = targetType.changeParameterType(spreadArgPos + i, arg);
448 }
449 target = target.asType(targetType);
450
451 MethodType srcType = targetType
452 .replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType);
453 // Now build a LambdaForm.
454 MethodType lambdaType = srcType.invokerType();
455 Name[] names = arguments(spreadArgCount + 2, lambdaType);
456 int nameCursor = lambdaType.parameterCount();
457 int[] indexes = new int[targetType.parameterCount()];
458
459 for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) {
460 Class<?> src = lambdaType.parameterType(i);
461 if (i == spreadArgPos) {
462 // Spread the array.
463 MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType);
464 Name array = names[argIndex];
465 names[nameCursor++] = new Name(Lazy.NF_checkSpreadArgument, array, spreadArgCount);
466 for (int j = 0; j < spreadArgCount; i++, j++) {
467 indexes[i] = nameCursor;
468 names[nameCursor++] = new Name(aload, array, j);
469 }
470 } else if (i < indexes.length) {
471 indexes[i] = argIndex;
472 }
473 }
474 assert(nameCursor == names.length-1); // leave room for the final call
475
476 // Build argument array for the call.
477 Name[] targetArgs = new Name[targetType.parameterCount()];
478 for (int i = 0; i < targetType.parameterCount(); i++) {
479 int idx = indexes[i];
480 targetArgs[i] = names[idx];
481 }
482 names[names.length - 1] = new Name(target, (Object[]) targetArgs);
483
484 LambdaForm form = new LambdaForm("spread", lambdaType.parameterCount(), names);
485 return SimpleMethodHandle.make(srcType, form);
486 }
487
488 static void checkSpreadArgument(Object av, int n) {
489 if (av == null) {
490 if (n == 0) return;
491 } else if (av instanceof Object[]) {
492 int len = ((Object[])av).length;
493 if (len == n) return;
494 } else {
495 int len = java.lang.reflect.Array.getLength(av);
496 if (len == n) return;
497 }
498 // fall through to error:
499 throw newIllegalArgumentException("array is not of length "+n);
500 }
501
502 /**
503 * Pre-initialized NamedFunctions for bootstrapping purposes.
504 * Factored in an inner class to delay initialization until first usage.
505 */
506 private static class Lazy {
507 private static final Class<?> MHI = MethodHandleImpl.class;
508
509 static final NamedFunction NF_checkSpreadArgument;
510 static final NamedFunction NF_guardWithCatch;
511 static final NamedFunction NF_selectAlternative;
512 static final NamedFunction NF_throwException;
513
514 static final MethodHandle MH_castReference;
515 static final MethodHandle MH_copyAsPrimitiveArray;
516 static final MethodHandle MH_fillNewTypedArray;
517 static final MethodHandle MH_fillNewArray;
518 static final MethodHandle MH_arrayIdentity;
519
520 static {
521 try {
522 NF_checkSpreadArgument = new NamedFunction(MHI.getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
523 NF_guardWithCatch = new NamedFunction(MHI.getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class,
524 MethodHandle.class, Object[].class));
525 NF_selectAlternative = new NamedFunction(MHI.getDeclaredMethod("selectAlternative", boolean.class, MethodHandle.class,
526 MethodHandle.class));
527 NF_throwException = new NamedFunction(MHI.getDeclaredMethod("throwException", Throwable.class));
528
529 NF_checkSpreadArgument.resolve();
530 NF_guardWithCatch.resolve();
531 NF_selectAlternative.resolve();
532 NF_throwException.resolve();
533
534 MH_castReference = IMPL_LOOKUP.findStatic(MHI, "castReference",
535 MethodType.methodType(Object.class, Class.class, Object.class));
536 MH_copyAsPrimitiveArray = IMPL_LOOKUP.findStatic(MHI, "copyAsPrimitiveArray",
537 MethodType.methodType(Object.class, Wrapper.class, Object[].class));
538 MH_arrayIdentity = IMPL_LOOKUP.findStatic(MHI, "identity",
539 MethodType.methodType(Object[].class, Object[].class));
540 MH_fillNewArray = IMPL_LOOKUP.findStatic(MHI, "fillNewArray",
541 MethodType.methodType(Object[].class, Integer.class, Object[].class));
542 MH_fillNewTypedArray = IMPL_LOOKUP.findStatic(MHI, "fillNewTypedArray",
543 MethodType.methodType(Object[].class, Object[].class, Integer.class, Object[].class));
544 } catch (ReflectiveOperationException ex) {
545 throw newInternalError(ex);
546 }
547 }
548 }
549
550 /** Factory method: Collect or filter selected argument(s). */
551 static MethodHandle makeCollectArguments(MethodHandle target,
552 MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) {
553 MethodType targetType = target.type(); // (a..., c, [b...])=>r
554 MethodType collectorType = collector.type(); // (b...)=>c
555 int collectArgCount = collectorType.parameterCount();
556 Class<?> collectValType = collectorType.returnType();
557 int collectValCount = (collectValType == void.class ? 0 : 1);
558 MethodType srcType = targetType // (a..., [b...])=>r
559 .dropParameterTypes(collectArgPos, collectArgPos+collectValCount);
560 if (!retainOriginalArgs) { // (a..., b...)=>r
561 srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterList());
562 }
563 // in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ]
564 // out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ]
565 // out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ]
566
567 // Now build a LambdaForm.
568 MethodType lambdaType = srcType.invokerType();
569 Name[] names = arguments(2, lambdaType);
570 final int collectNamePos = names.length - 2;
571 final int targetNamePos = names.length - 1;
572
573 Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount);
574 names[collectNamePos] = new Name(collector, (Object[]) collectorArgs);
575
576 // Build argument array for the target.
577 // Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ].
578 // Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ].
579 Name[] targetArgs = new Name[targetType.parameterCount()];
580 int inputArgPos = 1; // incoming LF args to copy to target
581 int targetArgPos = 0; // fill pointer for targetArgs
582 int chunk = collectArgPos; // |headArgs|
583 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
584 inputArgPos += chunk;
585 targetArgPos += chunk;
586 if (collectValType != void.class) {
587 targetArgs[targetArgPos++] = names[collectNamePos];
588 }
589 chunk = collectArgCount;
590 if (retainOriginalArgs) {
591 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
592 targetArgPos += chunk; // optionally pass on the collected chunk
593 }
594 inputArgPos += chunk;
595 chunk = targetArgs.length - targetArgPos; // all the rest
596 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
597 assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also
598 names[targetNamePos] = new Name(target, (Object[]) targetArgs);
599
600 LambdaForm form = new LambdaForm("collect", lambdaType.parameterCount(), names);
601 return SimpleMethodHandle.make(srcType, form);
602 }
603
604 @LambdaForm.Hidden
605 static
606 MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
607 return testResult ? target : fallback;
608 }
609
610 static
611 MethodHandle makeGuardWithTest(MethodHandle test,
612 MethodHandle target,
613 MethodHandle fallback) {
614 MethodType basicType = target.type().basicType();
615 MethodHandle invokeBasic = MethodHandles.basicInvoker(basicType);
616 int arity = basicType.parameterCount();
617 int extraNames = 3;
618 MethodType lambdaType = basicType.invokerType();
619 Name[] names = arguments(extraNames, lambdaType);
620
621 Object[] testArgs = Arrays.copyOfRange(names, 1, 1 + arity, Object[].class);
622 Object[] targetArgs = Arrays.copyOfRange(names, 0, 1 + arity, Object[].class);
623
624 // call test
625 names[arity + 1] = new Name(test, testArgs);
626
627 // call selectAlternative
628 Object[] selectArgs = { names[arity + 1], target, fallback };
629 names[arity + 2] = new Name(Lazy.NF_selectAlternative, selectArgs);
630 targetArgs[0] = names[arity + 2];
631
632 // call target or fallback
633 names[arity + 3] = new Name(new NamedFunction(invokeBasic), targetArgs);
634
635 LambdaForm form = new LambdaForm("guard", lambdaType.parameterCount(), names);
636 return SimpleMethodHandle.make(target.type(), form);
637 }
638
639 /**
640 * The LambdaForm shape for catchException combinator is the following:
641 * <blockquote><pre>{@code
642 * guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{
643 * t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L);
644 * t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L);
645 * t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L);
646 * t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L);
647 * t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L);
648 * t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L);
649 * t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L);
650 * t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I}
651 * }</pre></blockquote>
652 *
653 * argL0 and argL2 are target and catcher method handles. argL1 is exception class.
654 * argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[]
655 * (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()).
656 *
657 * Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms
658 * among catchException combinators with the same basic type.
659 */
660 private static LambdaForm makeGuardWithCatchForm(MethodType basicType) {
661 MethodType lambdaType = basicType.invokerType();
662
663 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC);
664 if (lform != null) {
665 return lform;
666 }
667 final int THIS_MH = 0; // the BMH_LLLLL
668 final int ARG_BASE = 1; // start of incoming arguments
669 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
670
671 int nameCursor = ARG_LIMIT;
672 final int GET_TARGET = nameCursor++;
673 final int GET_CLASS = nameCursor++;
674 final int GET_CATCHER = nameCursor++;
675 final int GET_COLLECT_ARGS = nameCursor++;
676 final int GET_UNBOX_RESULT = nameCursor++;
677 final int BOXED_ARGS = nameCursor++;
678 final int TRY_CATCH = nameCursor++;
679 final int UNBOX_RESULT = nameCursor++;
680
681 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
682
683 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
684 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
685 names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]);
686 names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]);
687 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]);
688 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]);
689
690 // FIXME: rework argument boxing/result unboxing logic for LF interpretation
691
692 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
693 MethodType collectArgsType = basicType.changeReturnType(Object.class);
694 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
695 Object[] args = new Object[invokeBasic.type().parameterCount()];
696 args[0] = names[GET_COLLECT_ARGS];
697 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
698 names[BOXED_ARGS] = new Name(new NamedFunction(invokeBasic), args);
699
700 // t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L);
701 Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]};
702 names[TRY_CATCH] = new Name(Lazy.NF_guardWithCatch, gwcArgs);
703
704 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
705 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
706 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]};
707 names[UNBOX_RESULT] = new Name(new NamedFunction(invokeBasicUnbox), unboxArgs);
708
709 lform = new LambdaForm("guardWithCatch", lambdaType.parameterCount(), names);
710
711 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform);
712 }
713
714 static
715 MethodHandle makeGuardWithCatch(MethodHandle target,
716 Class<? extends Throwable> exType,
717 MethodHandle catcher) {
718 MethodType type = target.type();
719 LambdaForm form = makeGuardWithCatchForm(type.basicType());
720
721 // Prepare auxiliary method handles used during LambdaForm interpretation.
722 // Box arguments and wrap them into Object[]: ValueConversions.array().
723 MethodType varargsType = type.changeReturnType(Object[].class);
724 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
725 // Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore().
726 MethodHandle unboxResult;
727 if (type.returnType().isPrimitive()) {
728 unboxResult = ValueConversions.unbox(type.returnType());
729 } else {
730 unboxResult = ValueConversions.identity();
731 }
732
733 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
734 BoundMethodHandle mh;
735 try {
736 mh = (BoundMethodHandle)
737 data.constructor().invokeBasic(type, form, (Object) target, (Object) exType, (Object) catcher,
738 (Object) collectArgs, (Object) unboxResult);
739 } catch (Throwable ex) {
740 throw uncaughtException(ex);
741 }
742 assert(mh.type() == type);
743 return mh;
744 }
745
746 /**
747 * Intrinsified during LambdaForm compilation
748 * (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}).
749 */
750 @LambdaForm.Hidden
751 static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher,
752 Object... av) throws Throwable {
753 // Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case.
754 try {
755 return target.asFixedArity().invokeWithArguments(av);
756 } catch (Throwable t) {
757 if (!exType.isInstance(t)) throw t;
758 return catcher.asFixedArity().invokeWithArguments(prepend(t, av));
759 }
760 }
761
762 /** Prepend an element {@code elem} to an {@code array}. */
763 @LambdaForm.Hidden
764 private static Object[] prepend(Object elem, Object[] array) {
765 Object[] newArray = new Object[array.length+1];
766 newArray[0] = elem;
767 System.arraycopy(array, 0, newArray, 1, array.length);
768 return newArray;
769 }
770
771 static
772 MethodHandle throwException(MethodType type) {
773 assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
774 int arity = type.parameterCount();
775 if (arity > 1) {
776 MethodHandle mh = throwException(type.dropParameterTypes(1, arity));
777 mh = MethodHandles.dropArguments(mh, 1, type.parameterList().subList(1, arity));
778 return mh;
779 }
780 return makePairwiseConvert(Lazy.NF_throwException.resolvedHandle(), type, 2);
781 }
782
783 static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
784
785 static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
786 static MethodHandle fakeMethodHandleInvoke(MemberName method) {
787 int idx;
788 assert(method.isMethodHandleInvoke());
789 switch (method.getName()) {
790 case "invoke": idx = 0; break;
791 case "invokeExact": idx = 1; break;
792 default: throw new InternalError(method.getName());
793 }
794 MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
795 if (mh != null) return mh;
796 MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
797 MethodHandle.class, Object[].class);
798 mh = throwException(type);
799 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
800 if (!method.getInvocationType().equals(mh.type()))
801 throw new InternalError(method.toString());
802 mh = mh.withInternalMemberName(method);
803 mh = mh.asVarargsCollector(Object[].class);
804 assert(method.isVarargs());
805 FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
806 return mh;
807 }
808
809 /**
810 * Create an alias for the method handle which, when called,
811 * appears to be called from the same class loader and protection domain
812 * as hostClass.
813 * This is an expensive no-op unless the method which is called
814 * is sensitive to its caller. A small number of system methods
815 * are in this category, including Class.forName and Method.invoke.
816 */
817 static
818 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
819 return BindCaller.bindCaller(mh, hostClass);
820 }
821
822 // Put the whole mess into its own nested class.
823 // That way we can lazily load the code and set up the constants.
824 private static class BindCaller {
825 static
826 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
827 // Do not use this function to inject calls into system classes.
828 if (hostClass == null
829 || (hostClass.isArray() ||
830 hostClass.isPrimitive() ||
831 hostClass.getName().startsWith("java.") ||
832 hostClass.getName().startsWith("sun."))) {
833 throw new InternalError(); // does not happen, and should not anyway
834 }
835 // For simplicity, convert mh to a varargs-like method.
836 MethodHandle vamh = prepareForInvoker(mh);
837 // Cache the result of makeInjectedInvoker once per argument class.
838 MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
839 return restoreToType(bccInvoker.bindTo(vamh), mh.type(), mh.internalMemberName(), hostClass);
840 }
841
842 private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
843 Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null);
844 if (hostClass.getClassLoader() != bcc.getClassLoader())
845 throw new InternalError(hostClass.getName()+" (CL)");
846 try {
847 if (hostClass.getProtectionDomain() != bcc.getProtectionDomain())
848 throw new InternalError(hostClass.getName()+" (PD)");
849 } catch (SecurityException ex) {
850 // Self-check was blocked by security manager. This is OK.
851 // In fact the whole try body could be turned into an assertion.
852 }
853 try {
854 MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class));
855 init.invokeExact(); // force initialization of the class
856 } catch (Throwable ex) {
857 throw uncaughtException(ex);
858 }
859 MethodHandle bccInvoker;
860 try {
861 MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
862 bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT);
863 } catch (ReflectiveOperationException ex) {
864 throw uncaughtException(ex);
865 }
866 // Test the invoker, to ensure that it really injects into the right place.
867 try {
868 MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
869 Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc});
870 } catch (Throwable ex) {
871 throw new InternalError(ex);
872 }
873 return bccInvoker;
874 }
875 private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() {
876 @Override protected MethodHandle computeValue(Class<?> hostClass) {
877 return makeInjectedInvoker(hostClass);
878 }
879 };
880
881 // Adapt mh so that it can be called directly from an injected invoker:
882 private static MethodHandle prepareForInvoker(MethodHandle mh) {
883 mh = mh.asFixedArity();
884 MethodType mt = mh.type();
885 int arity = mt.parameterCount();
886 MethodHandle vamh = mh.asType(mt.generic());
887 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
888 vamh = vamh.asSpreader(Object[].class, arity);
889 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
890 return vamh;
891 }
892
893 // Undo the adapter effect of prepareForInvoker:
894 private static MethodHandle restoreToType(MethodHandle vamh, MethodType type,
895 MemberName member,
896 Class<?> hostClass) {
897 MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount());
898 mh = mh.asType(type);
899 mh = new WrappedMember(mh, type, member, hostClass);
900 return mh;
901 }
902
903 private static final MethodHandle MH_checkCallerClass;
904 static {
905 final Class<?> THIS_CLASS = BindCaller.class;
906 assert(checkCallerClass(THIS_CLASS, THIS_CLASS));
907 try {
908 MH_checkCallerClass = IMPL_LOOKUP
909 .findStatic(THIS_CLASS, "checkCallerClass",
910 MethodType.methodType(boolean.class, Class.class, Class.class));
911 assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS, THIS_CLASS));
912 } catch (Throwable ex) {
913 throw new InternalError(ex);
914 }
915 }
916
917 @CallerSensitive
918 private static boolean checkCallerClass(Class<?> expected, Class<?> expected2) {
919 // This method is called via MH_checkCallerClass and so it's
920 // correct to ask for the immediate caller here.
921 Class<?> actual = Reflection.getCallerClass();
922 if (actual != expected && actual != expected2)
923 throw new InternalError("found "+actual.getName()+", expected "+expected.getName()
924 +(expected == expected2 ? "" : ", or else "+expected2.getName()));
925 return true;
926 }
927
928 private static final byte[] T_BYTES;
929 static {
930 final Object[] values = {null};
931 AccessController.doPrivileged(new PrivilegedAction<Void>() {
932 public Void run() {
933 try {
934 Class<T> tClass = T.class;
935 String tName = tClass.getName();
936 String tResource = tName.substring(tName.lastIndexOf('.')+1)+".class";
937 java.net.URLConnection uconn = tClass.getResource(tResource).openConnection();
938 int len = uconn.getContentLength();
939 byte[] bytes = new byte[len];
940 try (java.io.InputStream str = uconn.getInputStream()) {
941 int nr = str.read(bytes);
942 if (nr != len) throw new java.io.IOException(tResource);
943 }
944 values[0] = bytes;
945 } catch (java.io.IOException ex) {
946 throw new InternalError(ex);
947 }
948 return null;
949 }
950 });
951 T_BYTES = (byte[]) values[0];
952 }
953
954 // The following class is used as a template for Unsafe.defineAnonymousClass:
955 private static class T {
956 static void init() { } // side effect: initializes this class
957 static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
958 return vamh.invokeExact(args);
959 }
960 }
961 }
962
963
964 /** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */
965 static class WrappedMember extends MethodHandle {
966 private final MethodHandle target;
967 private final MemberName member;
968 private final Class<?> callerClass;
969
970 private WrappedMember(MethodHandle target, MethodType type, MemberName member, Class<?> callerClass) {
971 super(type, reinvokerForm(target));
972 this.target = target;
973 this.member = member;
974 this.callerClass = callerClass;
975 }
976
977 @Override
978 MethodHandle reinvokerTarget() {
979 return target;
980 }
981 @Override
982 public MethodHandle asTypeUncached(MethodType newType) {
983 // This MH is an alias for target, except for the MemberName
984 // Drop the MemberName if there is any conversion.
985 return asTypeCache = target.asType(newType);
986 }
987 @Override
988 MemberName internalMemberName() {
989 return member;
990 }
991 @Override
992 Class<?> internalCallerClass() {
993 return callerClass;
994 }
995 @Override
996 boolean isInvokeSpecial() {
997 return target.isInvokeSpecial();
998 }
999 @Override
1000 MethodHandle viewAsType(MethodType newType) {
1001 return new WrappedMember(target, newType, member, callerClass);
1002 }
1003 }
1004
1005 static MethodHandle makeWrappedMember(MethodHandle target, MemberName member) {
1006 if (member.equals(target.internalMemberName()))
1007 return target;
1008 return new WrappedMember(target, target.type(), member, null);
1009 }
1010
1011 /// Collection of multiple arguments.
1012
1013 private static MethodHandle findCollector(String name, int nargs, Class<?> rtype, Class<?>... ptypes) {
1014 MethodType type = MethodType.genericMethodType(nargs)
1015 .changeReturnType(rtype)
1016 .insertParameterTypes(0, ptypes);
1017 try {
1018 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, name, type);
1019 } catch (ReflectiveOperationException ex) {
1020 return null;
1021 }
1022 }
1023
1024 private static final Object[] NO_ARGS_ARRAY = {};
1025 private static Object[] makeArray(Object... args) { return args; }
1026 private static Object[] array() { return NO_ARGS_ARRAY; }
1027 private static Object[] array(Object a0)
1028 { return makeArray(a0); }
1029 private static Object[] array(Object a0, Object a1)
1030 { return makeArray(a0, a1); }
1031 private static Object[] array(Object a0, Object a1, Object a2)
1032 { return makeArray(a0, a1, a2); }
1033 private static Object[] array(Object a0, Object a1, Object a2, Object a3)
1034 { return makeArray(a0, a1, a2, a3); }
1035 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1036 Object a4)
1037 { return makeArray(a0, a1, a2, a3, a4); }
1038 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1039 Object a4, Object a5)
1040 { return makeArray(a0, a1, a2, a3, a4, a5); }
1041 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1042 Object a4, Object a5, Object a6)
1043 { return makeArray(a0, a1, a2, a3, a4, a5, a6); }
1044 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1045 Object a4, Object a5, Object a6, Object a7)
1046 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7); }
1047 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1048 Object a4, Object a5, Object a6, Object a7,
1049 Object a8)
1050 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8); }
1051 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1052 Object a4, Object a5, Object a6, Object a7,
1053 Object a8, Object a9)
1054 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
1055 private static MethodHandle[] makeArrays() {
1056 ArrayList<MethodHandle> mhs = new ArrayList<>();
1057 for (;;) {
1058 MethodHandle mh = findCollector("array", mhs.size(), Object[].class);
1059 if (mh == null) break;
1060 mhs.add(mh);
1061 }
1062 assert(mhs.size() == 11); // current number of methods
1063 return mhs.toArray(new MethodHandle[MAX_ARITY+1]);
1064 }
1065 private static final MethodHandle[] ARRAYS = makeArrays();
1066
1067 // filling versions of the above:
1068 // using Integer len instead of int len and no varargs to avoid bootstrapping problems
1069 private static Object[] fillNewArray(Integer len, Object[] /*not ...*/ args) {
1070 Object[] a = new Object[len];
1071 fillWithArguments(a, 0, args);
1072 return a;
1073 }
1074 private static Object[] fillNewTypedArray(Object[] example, Integer len, Object[] /*not ...*/ args) {
1075 Object[] a = Arrays.copyOf(example, len);
1076 assert(a.getClass() != Object[].class);
1077 fillWithArguments(a, 0, args);
1078 return a;
1079 }
1080 private static void fillWithArguments(Object[] a, int pos, Object... args) {
1081 System.arraycopy(args, 0, a, pos, args.length);
1082 }
1083 // using Integer pos instead of int pos to avoid bootstrapping problems
1084 private static Object[] fillArray(Integer pos, Object[] a, Object a0)
1085 { fillWithArguments(a, pos, a0); return a; }
1086 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1)
1087 { fillWithArguments(a, pos, a0, a1); return a; }
1088 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2)
1089 { fillWithArguments(a, pos, a0, a1, a2); return a; }
1090 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3)
1091 { fillWithArguments(a, pos, a0, a1, a2, a3); return a; }
1092 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1093 Object a4)
1094 { fillWithArguments(a, pos, a0, a1, a2, a3, a4); return a; }
1095 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1096 Object a4, Object a5)
1097 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5); return a; }
1098 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1099 Object a4, Object a5, Object a6)
1100 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6); return a; }
1101 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1102 Object a4, Object a5, Object a6, Object a7)
1103 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7); return a; }
1104 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1105 Object a4, Object a5, Object a6, Object a7,
1106 Object a8)
1107 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8); return a; }
1108 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1109 Object a4, Object a5, Object a6, Object a7,
1110 Object a8, Object a9)
1111 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); return a; }
1112 private static MethodHandle[] makeFillArrays() {
1113 ArrayList<MethodHandle> mhs = new ArrayList<>();
1114 mhs.add(null); // there is no empty fill; at least a0 is required
1115 for (;;) {
1116 MethodHandle mh = findCollector("fillArray", mhs.size(), Object[].class, Integer.class, Object[].class);
1117 if (mh == null) break;
1118 mhs.add(mh);
1119 }
1120 assert(mhs.size() == 11); // current number of methods
1121 return mhs.toArray(new MethodHandle[0]);
1122 }
1123 private static final MethodHandle[] FILL_ARRAYS = makeFillArrays();
1124
1125 private static Object copyAsPrimitiveArray(Wrapper w, Object... boxes) {
1126 Object a = w.makeArray(boxes.length);
1127 w.copyArrayUnboxing(boxes, 0, a, 0, boxes.length);
1128 return a;
1129 }
1130
1131 /** Return a method handle that takes the indicated number of Object
1132 * arguments and returns an Object array of them, as if for varargs.
1133 */
1134 static MethodHandle varargsArray(int nargs) {
1135 MethodHandle mh = ARRAYS[nargs];
1136 if (mh != null) return mh;
1137 mh = findCollector("array", nargs, Object[].class);
1138 if (mh != null) return ARRAYS[nargs] = mh;
1139 mh = buildVarargsArray(Lazy.MH_fillNewArray, Lazy.MH_arrayIdentity, nargs);
1140 assert(assertCorrectArity(mh, nargs));
1141 return ARRAYS[nargs] = mh;
1142 }
1143
1144 private static boolean assertCorrectArity(MethodHandle mh, int arity) {
1145 assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh;
1146 return true;
1147 }
1148
1149 // Array identity function (used as Lazy.MH_arrayIdentity).
1150 static <T> T[] identity(T[] x) {
1151 return x;
1152 }
1153
1154 private static MethodHandle buildVarargsArray(MethodHandle newArray, MethodHandle finisher, int nargs) {
1155 // Build up the result mh as a sequence of fills like this:
1156 // finisher(fill(fill(newArrayWA(23,x1..x10),10,x11..x20),20,x21..x23))
1157 // The various fill(_,10*I,___*[J]) are reusable.
1158 int leftLen = Math.min(nargs, LEFT_ARGS); // absorb some arguments immediately
1159 int rightLen = nargs - leftLen;
1160 MethodHandle leftCollector = newArray.bindTo(nargs);
1161 leftCollector = leftCollector.asCollector(Object[].class, leftLen);
1162 MethodHandle mh = finisher;
1163 if (rightLen > 0) {
1164 MethodHandle rightFiller = fillToRight(LEFT_ARGS + rightLen);
1165 if (mh == Lazy.MH_arrayIdentity)
1166 mh = rightFiller;
1167 else
1168 mh = MethodHandles.collectArguments(mh, 0, rightFiller);
1169 }
1170 if (mh == Lazy.MH_arrayIdentity)
1171 mh = leftCollector;
1172 else
1173 mh = MethodHandles.collectArguments(mh, 0, leftCollector);
1174 return mh;
1175 }
1176
1177 private static final int LEFT_ARGS = (FILL_ARRAYS.length - 1);
1178 private static final MethodHandle[] FILL_ARRAY_TO_RIGHT = new MethodHandle[MAX_ARITY+1];
1179 /** fill_array_to_right(N).invoke(a, argL..arg[N-1])
1180 * fills a[L]..a[N-1] with corresponding arguments,
1181 * and then returns a. The value L is a global constant (LEFT_ARGS).
1182 */
1183 private static MethodHandle fillToRight(int nargs) {
1184 MethodHandle filler = FILL_ARRAY_TO_RIGHT[nargs];
1185 if (filler != null) return filler;
1186 filler = buildFiller(nargs);
1187 assert(assertCorrectArity(filler, nargs - LEFT_ARGS + 1));
1188 return FILL_ARRAY_TO_RIGHT[nargs] = filler;
1189 }
1190 private static MethodHandle buildFiller(int nargs) {
1191 if (nargs <= LEFT_ARGS)
1192 return Lazy.MH_arrayIdentity; // no args to fill; return the array unchanged
1193 // we need room for both mh and a in mh.invoke(a, arg*[nargs])
1194 final int CHUNK = LEFT_ARGS;
1195 int rightLen = nargs % CHUNK;
1196 int midLen = nargs - rightLen;
1197 if (rightLen == 0) {
1198 midLen = nargs - (rightLen = CHUNK);
1199 if (FILL_ARRAY_TO_RIGHT[midLen] == null) {
1200 // build some precursors from left to right
1201 for (int j = LEFT_ARGS % CHUNK; j < midLen; j += CHUNK)
1202 if (j > LEFT_ARGS) fillToRight(j);
1203 }
1204 }
1205 if (midLen < LEFT_ARGS) rightLen = nargs - (midLen = LEFT_ARGS);
1206 assert(rightLen > 0);
1207 MethodHandle midFill = fillToRight(midLen); // recursive fill
1208 MethodHandle rightFill = FILL_ARRAYS[rightLen].bindTo(midLen); // [midLen..nargs-1]
1209 assert(midFill.type().parameterCount() == 1 + midLen - LEFT_ARGS);
1210 assert(rightFill.type().parameterCount() == 1 + rightLen);
1211
1212 // Combine the two fills:
1213 // right(mid(a, x10..x19), x20..x23)
1214 // The final product will look like this:
1215 // right(mid(newArrayLeft(24, x0..x9), x10..x19), x20..x23)
1216 if (midLen == LEFT_ARGS)
1217 return rightFill;
1218 else
1219 return MethodHandles.collectArguments(rightFill, 0, midFill);
1220 }
1221
1222 // Type-polymorphic version of varargs maker.
1223 private static final ClassValue<MethodHandle[]> TYPED_COLLECTORS
1224 = new ClassValue<MethodHandle[]>() {
1225 @Override
1226 protected MethodHandle[] computeValue(Class<?> type) {
1227 return new MethodHandle[256];
1228 }
1229 };
1230
1231 static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM
1232
1233 /** Return a method handle that takes the indicated number of
1234 * typed arguments and returns an array of them.
1235 * The type argument is the array type.
1236 */
1237 static MethodHandle varargsArray(Class<?> arrayType, int nargs) {
1238 Class<?> elemType = arrayType.getComponentType();
1239 if (elemType == null) throw new IllegalArgumentException("not an array: "+arrayType);
1240 // FIXME: Need more special casing and caching here.
1241 if (nargs >= MAX_JVM_ARITY/2 - 1) {
1242 int slots = nargs;
1243 final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH
1244 if (slots <= MAX_ARRAY_SLOTS && elemType.isPrimitive())
1245 slots *= Wrapper.forPrimitiveType(elemType).stackSlots();
1246 if (slots > MAX_ARRAY_SLOTS)
1247 throw new IllegalArgumentException("too many arguments: "+arrayType.getSimpleName()+", length "+nargs);
1248 }
1249 if (elemType == Object.class)
1250 return varargsArray(nargs);
1251 // other cases: primitive arrays, subtypes of Object[]
1252 MethodHandle cache[] = TYPED_COLLECTORS.get(elemType);
1253 MethodHandle mh = nargs < cache.length ? cache[nargs] : null;
1254 if (mh != null) return mh;
1255 if (nargs == 0) {
1256 Object example = java.lang.reflect.Array.newInstance(arrayType.getComponentType(), 0);
1257 mh = MethodHandles.constant(arrayType, example);
1258 } else if (elemType.isPrimitive()) {
1259 MethodHandle builder = Lazy.MH_fillNewArray;
1260 MethodHandle producer = buildArrayProducer(arrayType);
1261 mh = buildVarargsArray(builder, producer, nargs);
1262 } else {
1263 Class<? extends Object[]> objArrayType = arrayType.asSubclass(Object[].class);
1264 Object[] example = Arrays.copyOf(NO_ARGS_ARRAY, 0, objArrayType);
1265 MethodHandle builder = Lazy.MH_fillNewTypedArray.bindTo(example);
1266 MethodHandle producer = Lazy.MH_arrayIdentity; // must be weakly typed
1267 mh = buildVarargsArray(builder, producer, nargs);
1268 }
1269 mh = mh.asType(MethodType.methodType(arrayType, Collections.<Class<?>>nCopies(nargs, elemType)));
1270 assert(assertCorrectArity(mh, nargs));
1271 if (nargs < cache.length)
1272 cache[nargs] = mh;
1273 return mh;
1274 }
1275
1276 private static MethodHandle buildArrayProducer(Class<?> arrayType) {
1277 Class<?> elemType = arrayType.getComponentType();
1278 assert(elemType.isPrimitive());
1279 return Lazy.MH_copyAsPrimitiveArray.bindTo(Wrapper.forPrimitiveType(elemType));
1280 }
1281 }