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, false);
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, arrayType);
355 }
356
357 private static final class AsVarargsCollector extends DelegatingMethodHandle {
358 private final MethodHandle target;
359 private final Class<?> arrayType;
360 private /*@Stable*/ MethodHandle asCollectorCache;
361
362 AsVarargsCollector(MethodHandle target, Class<?> arrayType) {
363 this(target.type(), target, arrayType);
364 }
365 AsVarargsCollector(MethodType type, MethodHandle target, Class<?> arrayType) {
366 super(type, target);
367 this.target = target;
368 this.arrayType = arrayType;
369 this.asCollectorCache = target.asCollector(arrayType, 0);
370 }
371
372 @Override
373 public boolean isVarargsCollector() {
374 return true;
375 }
376
377 @Override
378 protected MethodHandle getTarget() {
379 return target;
380 }
381
382 @Override
383 public MethodHandle asFixedArity() {
384 return target;
385 }
386
387 @Override
388 public MethodHandle asTypeUncached(MethodType newType) {
389 MethodType type = this.type();
390 int collectArg = type.parameterCount() - 1;
391 int newArity = newType.parameterCount();
392 if (newArity == collectArg+1 &&
393 type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
394 // if arity and trailing parameter are compatible, do normal thing
395 return asTypeCache = asFixedArity().asType(newType);
396 }
397 // check cache
398 MethodHandle acc = asCollectorCache;
399 if (acc != null && acc.type().parameterCount() == newArity)
400 return asTypeCache = acc.asType(newType);
401 // build and cache a collector
402 int arrayLength = newArity - collectArg;
403 MethodHandle collector;
404 try {
405 collector = asFixedArity().asCollector(arrayType, arrayLength);
406 assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
407 } catch (IllegalArgumentException ex) {
408 throw new WrongMethodTypeException("cannot build collector", ex);
409 }
410 asCollectorCache = collector;
411 return asTypeCache = collector.asType(newType);
412 }
413
414 @Override
415 boolean viewAsTypeChecks(MethodType newType, boolean strict) {
416 super.viewAsTypeChecks(newType, true);
417 if (strict) return true;
418 // extra assertion for non-strict checks:
419 assert (type().lastParameterType().getComponentType()
420 .isAssignableFrom(
421 newType.lastParameterType().getComponentType()))
422 : Arrays.asList(this, newType);
423 return true;
424 }
425 }
426
427 /** Factory method: Spread selected argument. */
428 static MethodHandle makeSpreadArguments(MethodHandle target,
429 Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
430 MethodType targetType = target.type();
431
432 for (int i = 0; i < spreadArgCount; i++) {
433 Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i);
434 if (arg == null) arg = Object.class;
435 targetType = targetType.changeParameterType(spreadArgPos + i, arg);
436 }
437 target = target.asType(targetType);
438
439 MethodType srcType = targetType
440 .replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType);
441 // Now build a LambdaForm.
442 MethodType lambdaType = srcType.invokerType();
443 Name[] names = arguments(spreadArgCount + 2, lambdaType);
444 int nameCursor = lambdaType.parameterCount();
445 int[] indexes = new int[targetType.parameterCount()];
446
447 for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) {
448 Class<?> src = lambdaType.parameterType(i);
449 if (i == spreadArgPos) {
450 // Spread the array.
451 MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType);
452 Name array = names[argIndex];
453 names[nameCursor++] = new Name(Lazy.NF_checkSpreadArgument, array, spreadArgCount);
454 for (int j = 0; j < spreadArgCount; i++, j++) {
455 indexes[i] = nameCursor;
456 names[nameCursor++] = new Name(aload, array, j);
457 }
458 } else if (i < indexes.length) {
459 indexes[i] = argIndex;
460 }
461 }
462 assert(nameCursor == names.length-1); // leave room for the final call
463
464 // Build argument array for the call.
465 Name[] targetArgs = new Name[targetType.parameterCount()];
466 for (int i = 0; i < targetType.parameterCount(); i++) {
467 int idx = indexes[i];
468 targetArgs[i] = names[idx];
469 }
470 names[names.length - 1] = new Name(target, (Object[]) targetArgs);
471
472 LambdaForm form = new LambdaForm("spread", lambdaType.parameterCount(), names);
473 return SimpleMethodHandle.make(srcType, form);
474 }
475
476 static void checkSpreadArgument(Object av, int n) {
477 if (av == null) {
478 if (n == 0) return;
479 } else if (av instanceof Object[]) {
480 int len = ((Object[])av).length;
481 if (len == n) return;
482 } else {
483 int len = java.lang.reflect.Array.getLength(av);
484 if (len == n) return;
485 }
486 // fall through to error:
487 throw newIllegalArgumentException("array is not of length "+n);
488 }
489
490 /**
491 * Pre-initialized NamedFunctions for bootstrapping purposes.
492 * Factored in an inner class to delay initialization until first usage.
493 */
494 private static class Lazy {
495 private static final Class<?> MHI = MethodHandleImpl.class;
496
497 static final NamedFunction NF_checkSpreadArgument;
498 static final NamedFunction NF_guardWithCatch;
499 static final NamedFunction NF_selectAlternative;
500 static final NamedFunction NF_throwException;
501
502 static final MethodHandle MH_castReference;
503 static final MethodHandle MH_copyAsPrimitiveArray;
504 static final MethodHandle MH_fillNewTypedArray;
505 static final MethodHandle MH_fillNewArray;
506 static final MethodHandle MH_arrayIdentity;
507
508 static {
509 try {
510 NF_checkSpreadArgument = new NamedFunction(MHI.getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
511 NF_guardWithCatch = new NamedFunction(MHI.getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class,
512 MethodHandle.class, Object[].class));
513 NF_selectAlternative = new NamedFunction(MHI.getDeclaredMethod("selectAlternative", boolean.class, MethodHandle.class,
514 MethodHandle.class));
515 NF_throwException = new NamedFunction(MHI.getDeclaredMethod("throwException", Throwable.class));
516
517 NF_checkSpreadArgument.resolve();
518 NF_guardWithCatch.resolve();
519 NF_selectAlternative.resolve();
520 NF_throwException.resolve();
521
522 MH_castReference = IMPL_LOOKUP.findStatic(MHI, "castReference",
523 MethodType.methodType(Object.class, Class.class, Object.class));
524 MH_copyAsPrimitiveArray = IMPL_LOOKUP.findStatic(MHI, "copyAsPrimitiveArray",
525 MethodType.methodType(Object.class, Wrapper.class, Object[].class));
526 MH_arrayIdentity = IMPL_LOOKUP.findStatic(MHI, "identity",
527 MethodType.methodType(Object[].class, Object[].class));
528 MH_fillNewArray = IMPL_LOOKUP.findStatic(MHI, "fillNewArray",
529 MethodType.methodType(Object[].class, Integer.class, Object[].class));
530 MH_fillNewTypedArray = IMPL_LOOKUP.findStatic(MHI, "fillNewTypedArray",
531 MethodType.methodType(Object[].class, Object[].class, Integer.class, Object[].class));
532 } catch (ReflectiveOperationException ex) {
533 throw newInternalError(ex);
534 }
535 }
536 }
537
538 /** Factory method: Collect or filter selected argument(s). */
539 static MethodHandle makeCollectArguments(MethodHandle target,
540 MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) {
541 MethodType targetType = target.type(); // (a..., c, [b...])=>r
542 MethodType collectorType = collector.type(); // (b...)=>c
543 int collectArgCount = collectorType.parameterCount();
544 Class<?> collectValType = collectorType.returnType();
545 int collectValCount = (collectValType == void.class ? 0 : 1);
546 MethodType srcType = targetType // (a..., [b...])=>r
547 .dropParameterTypes(collectArgPos, collectArgPos+collectValCount);
548 if (!retainOriginalArgs) { // (a..., b...)=>r
549 srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterList());
550 }
551 // in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ]
552 // out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ]
553 // out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ]
554
555 // Now build a LambdaForm.
556 MethodType lambdaType = srcType.invokerType();
557 Name[] names = arguments(2, lambdaType);
558 final int collectNamePos = names.length - 2;
559 final int targetNamePos = names.length - 1;
560
561 Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount);
562 names[collectNamePos] = new Name(collector, (Object[]) collectorArgs);
563
564 // Build argument array for the target.
565 // Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ].
566 // Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ].
567 Name[] targetArgs = new Name[targetType.parameterCount()];
568 int inputArgPos = 1; // incoming LF args to copy to target
569 int targetArgPos = 0; // fill pointer for targetArgs
570 int chunk = collectArgPos; // |headArgs|
571 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
572 inputArgPos += chunk;
573 targetArgPos += chunk;
574 if (collectValType != void.class) {
575 targetArgs[targetArgPos++] = names[collectNamePos];
576 }
577 chunk = collectArgCount;
578 if (retainOriginalArgs) {
579 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
580 targetArgPos += chunk; // optionally pass on the collected chunk
581 }
582 inputArgPos += chunk;
583 chunk = targetArgs.length - targetArgPos; // all the rest
584 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
585 assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also
586 names[targetNamePos] = new Name(target, (Object[]) targetArgs);
587
588 LambdaForm form = new LambdaForm("collect", lambdaType.parameterCount(), names);
589 return SimpleMethodHandle.make(srcType, form);
590 }
591
592 @LambdaForm.Hidden
593 static
594 MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
595 return testResult ? target : fallback;
596 }
597
598 static
599 MethodHandle makeGuardWithTest(MethodHandle test,
600 MethodHandle target,
601 MethodHandle fallback) {
602 MethodType basicType = target.type().basicType();
603 MethodHandle invokeBasic = MethodHandles.basicInvoker(basicType);
604 int arity = basicType.parameterCount();
605 int extraNames = 3;
606 MethodType lambdaType = basicType.invokerType();
607 Name[] names = arguments(extraNames, lambdaType);
608
609 Object[] testArgs = Arrays.copyOfRange(names, 1, 1 + arity, Object[].class);
610 Object[] targetArgs = Arrays.copyOfRange(names, 0, 1 + arity, Object[].class);
611
612 // call test
613 names[arity + 1] = new Name(test, testArgs);
614
615 // call selectAlternative
616 Object[] selectArgs = { names[arity + 1], target, fallback };
617 names[arity + 2] = new Name(Lazy.NF_selectAlternative, selectArgs);
618 targetArgs[0] = names[arity + 2];
619
620 // call target or fallback
621 names[arity + 3] = new Name(new NamedFunction(invokeBasic), targetArgs);
622
623 LambdaForm form = new LambdaForm("guard", lambdaType.parameterCount(), names);
624 return SimpleMethodHandle.make(target.type(), form);
625 }
626
627 /**
628 * The LambaForm shape for catchException combinator is the following:
629 * <blockquote><pre>{@code
630 * guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{
631 * t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L);
632 * t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L);
633 * t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L);
634 * t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L);
635 * t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L);
636 * t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L);
637 * t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L);
638 * t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I}
639 * }</pre></blockquote>
640 *
641 * argL0 and argL2 are target and catcher method handles. argL1 is exception class.
642 * argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[]
643 * (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()).
644 *
645 * Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms
646 * among catchException combinators with the same basic type.
647 */
648 private static LambdaForm makeGuardWithCatchForm(MethodType basicType) {
649 MethodType lambdaType = basicType.invokerType();
650
651 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC);
652 if (lform != null) {
653 return lform;
654 }
655 final int THIS_MH = 0; // the BMH_LLLLL
656 final int ARG_BASE = 1; // start of incoming arguments
657 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
658
659 int nameCursor = ARG_LIMIT;
660 final int GET_TARGET = nameCursor++;
661 final int GET_CLASS = nameCursor++;
662 final int GET_CATCHER = nameCursor++;
663 final int GET_COLLECT_ARGS = nameCursor++;
664 final int GET_UNBOX_RESULT = nameCursor++;
665 final int BOXED_ARGS = nameCursor++;
666 final int TRY_CATCH = nameCursor++;
667 final int UNBOX_RESULT = nameCursor++;
668
669 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
670
671 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
672 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
673 names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]);
674 names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]);
675 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]);
676 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]);
677
678 // FIXME: rework argument boxing/result unboxing logic for LF interpretation
679
680 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
681 MethodType collectArgsType = basicType.changeReturnType(Object.class);
682 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
683 Object[] args = new Object[invokeBasic.type().parameterCount()];
684 args[0] = names[GET_COLLECT_ARGS];
685 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
686 names[BOXED_ARGS] = new Name(new NamedFunction(invokeBasic), args);
687
688 // t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L);
689 Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]};
690 names[TRY_CATCH] = new Name(Lazy.NF_guardWithCatch, gwcArgs);
691
692 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
693 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
694 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]};
695 names[UNBOX_RESULT] = new Name(new NamedFunction(invokeBasicUnbox), unboxArgs);
696
697 lform = new LambdaForm("guardWithCatch", lambdaType.parameterCount(), names);
698
699 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform);
700 }
701
702 static
703 MethodHandle makeGuardWithCatch(MethodHandle target,
704 Class<? extends Throwable> exType,
705 MethodHandle catcher) {
706 MethodType type = target.type();
707 LambdaForm form = makeGuardWithCatchForm(type.basicType());
708
709 // Prepare auxiliary method handles used during LambdaForm interpreation.
710 // Box arguments and wrap them into Object[]: ValueConversions.array().
711 MethodType varargsType = type.changeReturnType(Object[].class);
712 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
713 // Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore().
714 MethodHandle unboxResult;
715 if (type.returnType().isPrimitive()) {
716 unboxResult = ValueConversions.unbox(type.returnType());
717 } else {
718 unboxResult = ValueConversions.identity();
719 }
720
721 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
722 BoundMethodHandle mh;
723 try {
724 mh = (BoundMethodHandle)
725 data.constructor().invokeBasic(type, form, (Object) target, (Object) exType, (Object) catcher,
726 (Object) collectArgs, (Object) unboxResult);
727 } catch (Throwable ex) {
728 throw uncaughtException(ex);
729 }
730 assert(mh.type() == type);
731 return mh;
732 }
733
734 /**
735 * Intrinsified during LambdaForm compilation
736 * (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}).
737 */
738 @LambdaForm.Hidden
739 static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher,
740 Object... av) throws Throwable {
741 // Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case.
742 try {
743 return target.asFixedArity().invokeWithArguments(av);
744 } catch (Throwable t) {
745 if (!exType.isInstance(t)) throw t;
746 return catcher.asFixedArity().invokeWithArguments(prepend(t, av));
747 }
748 }
749
750 /** Prepend an element {@code elem} to an {@code array}. */
751 @LambdaForm.Hidden
752 private static Object[] prepend(Object elem, Object[] array) {
753 Object[] newArray = new Object[array.length+1];
754 newArray[0] = elem;
755 System.arraycopy(array, 0, newArray, 1, array.length);
756 return newArray;
757 }
758
759 static
760 MethodHandle throwException(MethodType type) {
761 assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
762 int arity = type.parameterCount();
763 if (arity > 1) {
764 MethodHandle mh = throwException(type.dropParameterTypes(1, arity));
765 mh = MethodHandles.dropArguments(mh, 1, type.parameterList().subList(1, arity));
766 return mh;
767 }
768 return makePairwiseConvert(Lazy.NF_throwException.resolvedHandle(), type, 2);
769 }
770
771 static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
772
773 static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
774 static MethodHandle fakeMethodHandleInvoke(MemberName method) {
775 int idx;
776 assert(method.isMethodHandleInvoke());
777 switch (method.getName()) {
778 case "invoke": idx = 0; break;
779 case "invokeExact": idx = 1; break;
780 default: throw new InternalError(method.getName());
781 }
782 MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
783 if (mh != null) return mh;
784 MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
785 MethodHandle.class, Object[].class);
786 mh = throwException(type);
787 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
788 if (!method.getInvocationType().equals(mh.type()))
789 throw new InternalError(method.toString());
790 mh = mh.withInternalMemberName(method, false);
791 mh = mh.asVarargsCollector(Object[].class);
792 assert(method.isVarargs());
793 FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
794 return mh;
795 }
796
797 /**
798 * Create an alias for the method handle which, when called,
799 * appears to be called from the same class loader and protection domain
800 * as hostClass.
801 * This is an expensive no-op unless the method which is called
802 * is sensitive to its caller. A small number of system methods
803 * are in this category, including Class.forName and Method.invoke.
804 */
805 static
806 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
807 return BindCaller.bindCaller(mh, hostClass);
808 }
809
810 // Put the whole mess into its own nested class.
811 // That way we can lazily load the code and set up the constants.
812 private static class BindCaller {
813 static
814 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
815 // Do not use this function to inject calls into system classes.
816 if (hostClass == null
817 || (hostClass.isArray() ||
818 hostClass.isPrimitive() ||
819 hostClass.getName().startsWith("java.") ||
820 hostClass.getName().startsWith("sun."))) {
821 throw new InternalError(); // does not happen, and should not anyway
822 }
823 // For simplicity, convert mh to a varargs-like method.
824 MethodHandle vamh = prepareForInvoker(mh);
825 // Cache the result of makeInjectedInvoker once per argument class.
826 MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
827 return restoreToType(bccInvoker.bindTo(vamh), mh, hostClass);
828 }
829
830 private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
831 Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null);
832 if (hostClass.getClassLoader() != bcc.getClassLoader())
833 throw new InternalError(hostClass.getName()+" (CL)");
834 try {
835 if (hostClass.getProtectionDomain() != bcc.getProtectionDomain())
836 throw new InternalError(hostClass.getName()+" (PD)");
837 } catch (SecurityException ex) {
838 // Self-check was blocked by security manager. This is OK.
839 // In fact the whole try body could be turned into an assertion.
840 }
841 try {
842 MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class));
843 init.invokeExact(); // force initialization of the class
844 } catch (Throwable ex) {
845 throw uncaughtException(ex);
846 }
847 MethodHandle bccInvoker;
848 try {
849 MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
850 bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT);
851 } catch (ReflectiveOperationException ex) {
852 throw uncaughtException(ex);
853 }
854 // Test the invoker, to ensure that it really injects into the right place.
855 try {
856 MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
857 Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc});
858 } catch (Throwable ex) {
859 throw new InternalError(ex);
860 }
861 return bccInvoker;
862 }
863 private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() {
864 @Override protected MethodHandle computeValue(Class<?> hostClass) {
865 return makeInjectedInvoker(hostClass);
866 }
867 };
868
869 // Adapt mh so that it can be called directly from an injected invoker:
870 private static MethodHandle prepareForInvoker(MethodHandle mh) {
871 mh = mh.asFixedArity();
872 MethodType mt = mh.type();
873 int arity = mt.parameterCount();
874 MethodHandle vamh = mh.asType(mt.generic());
875 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
876 vamh = vamh.asSpreader(Object[].class, arity);
877 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
878 return vamh;
879 }
880
881 // Undo the adapter effect of prepareForInvoker:
882 private static MethodHandle restoreToType(MethodHandle vamh,
883 MethodHandle original,
884 Class<?> hostClass) {
885 MethodType type = original.type();
886 MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount());
887 MemberName member = original.internalMemberName();
888 mh = mh.asType(type);
889 mh = new WrappedMember(mh, type, member, original.isInvokeSpecial(), hostClass);
890 return mh;
891 }
892
893 private static final MethodHandle MH_checkCallerClass;
894 static {
895 final Class<?> THIS_CLASS = BindCaller.class;
896 assert(checkCallerClass(THIS_CLASS, THIS_CLASS));
897 try {
898 MH_checkCallerClass = IMPL_LOOKUP
899 .findStatic(THIS_CLASS, "checkCallerClass",
900 MethodType.methodType(boolean.class, Class.class, Class.class));
901 assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS, THIS_CLASS));
902 } catch (Throwable ex) {
903 throw new InternalError(ex);
904 }
905 }
906
907 @CallerSensitive
908 private static boolean checkCallerClass(Class<?> expected, Class<?> expected2) {
909 // This method is called via MH_checkCallerClass and so it's
910 // correct to ask for the immediate caller here.
911 Class<?> actual = Reflection.getCallerClass();
912 if (actual != expected && actual != expected2)
913 throw new InternalError("found "+actual.getName()+", expected "+expected.getName()
914 +(expected == expected2 ? "" : ", or else "+expected2.getName()));
915 return true;
916 }
917
918 private static final byte[] T_BYTES;
919 static {
920 final Object[] values = {null};
921 AccessController.doPrivileged(new PrivilegedAction<Void>() {
922 public Void run() {
923 try {
924 Class<T> tClass = T.class;
925 String tName = tClass.getName();
926 String tResource = tName.substring(tName.lastIndexOf('.')+1)+".class";
927 java.net.URLConnection uconn = tClass.getResource(tResource).openConnection();
928 int len = uconn.getContentLength();
929 byte[] bytes = new byte[len];
930 try (java.io.InputStream str = uconn.getInputStream()) {
931 int nr = str.read(bytes);
932 if (nr != len) throw new java.io.IOException(tResource);
933 }
934 values[0] = bytes;
935 } catch (java.io.IOException ex) {
936 throw new InternalError(ex);
937 }
938 return null;
939 }
940 });
941 T_BYTES = (byte[]) values[0];
942 }
943
944 // The following class is used as a template for Unsafe.defineAnonymousClass:
945 private static class T {
946 static void init() { } // side effect: initializes this class
947 static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
948 return vamh.invokeExact(args);
949 }
950 }
951 }
952
953
954 /** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */
955 private static final class WrappedMember extends DelegatingMethodHandle {
956 private final MethodHandle target;
957 private final MemberName member;
958 private final Class<?> callerClass;
959 private final boolean isInvokeSpecial;
960
961 private WrappedMember(MethodHandle target, MethodType type,
962 MemberName member, boolean isInvokeSpecial,
963 Class<?> callerClass) {
964 super(type, target);
965 this.target = target;
966 this.member = member;
967 this.callerClass = callerClass;
968 this.isInvokeSpecial = isInvokeSpecial;
969 }
970
971 @Override
972 MemberName internalMemberName() {
973 return member;
974 }
975 @Override
976 Class<?> internalCallerClass() {
977 return callerClass;
978 }
979 @Override
980 boolean isInvokeSpecial() {
981 return isInvokeSpecial;
982 }
983 @Override
984 protected MethodHandle getTarget() {
985 return target;
986 }
987 @Override
988 public MethodHandle asTypeUncached(MethodType newType) {
989 // This MH is an alias for target, except for the MemberName
990 // Drop the MemberName if there is any conversion.
991 return asTypeCache = target.asType(newType);
992 }
993 }
994
995 static MethodHandle makeWrappedMember(MethodHandle target, MemberName member, boolean isInvokeSpecial) {
996 if (member.equals(target.internalMemberName()) && isInvokeSpecial == target.isInvokeSpecial())
997 return target;
998 return new WrappedMember(target, target.type(), member, isInvokeSpecial, null);
999 }
1000
1001 /// Collection of multiple arguments.
1002
1003 private static MethodHandle findCollector(String name, int nargs, Class<?> rtype, Class<?>... ptypes) {
1004 MethodType type = MethodType.genericMethodType(nargs)
1005 .changeReturnType(rtype)
1006 .insertParameterTypes(0, ptypes);
1007 try {
1008 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, name, type);
1009 } catch (ReflectiveOperationException ex) {
1010 return null;
1011 }
1012 }
1013
1014 private static final Object[] NO_ARGS_ARRAY = {};
1015 private static Object[] makeArray(Object... args) { return args; }
1016 private static Object[] array() { return NO_ARGS_ARRAY; }
1017 private static Object[] array(Object a0)
1018 { return makeArray(a0); }
1019 private static Object[] array(Object a0, Object a1)
1020 { return makeArray(a0, a1); }
1021 private static Object[] array(Object a0, Object a1, Object a2)
1022 { return makeArray(a0, a1, a2); }
1023 private static Object[] array(Object a0, Object a1, Object a2, Object a3)
1024 { return makeArray(a0, a1, a2, a3); }
1025 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1026 Object a4)
1027 { return makeArray(a0, a1, a2, a3, a4); }
1028 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1029 Object a4, Object a5)
1030 { return makeArray(a0, a1, a2, a3, a4, a5); }
1031 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1032 Object a4, Object a5, Object a6)
1033 { return makeArray(a0, a1, a2, a3, a4, a5, a6); }
1034 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1035 Object a4, Object a5, Object a6, Object a7)
1036 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7); }
1037 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1038 Object a4, Object a5, Object a6, Object a7,
1039 Object a8)
1040 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8); }
1041 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1042 Object a4, Object a5, Object a6, Object a7,
1043 Object a8, Object a9)
1044 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
1045 private static MethodHandle[] makeArrays() {
1046 ArrayList<MethodHandle> mhs = new ArrayList<>();
1047 for (;;) {
1048 MethodHandle mh = findCollector("array", mhs.size(), Object[].class);
1049 if (mh == null) break;
1050 mhs.add(mh);
1051 }
1052 assert(mhs.size() == 11); // current number of methods
1053 return mhs.toArray(new MethodHandle[MAX_ARITY+1]);
1054 }
1055 private static final MethodHandle[] ARRAYS = makeArrays();
1056
1057 // filling versions of the above:
1058 // using Integer len instead of int len and no varargs to avoid bootstrapping problems
1059 private static Object[] fillNewArray(Integer len, Object[] /*not ...*/ args) {
1060 Object[] a = new Object[len];
1061 fillWithArguments(a, 0, args);
1062 return a;
1063 }
1064 private static Object[] fillNewTypedArray(Object[] example, Integer len, Object[] /*not ...*/ args) {
1065 Object[] a = Arrays.copyOf(example, len);
1066 assert(a.getClass() != Object[].class);
1067 fillWithArguments(a, 0, args);
1068 return a;
1069 }
1070 private static void fillWithArguments(Object[] a, int pos, Object... args) {
1071 System.arraycopy(args, 0, a, pos, args.length);
1072 }
1073 // using Integer pos instead of int pos to avoid bootstrapping problems
1074 private static Object[] fillArray(Integer pos, Object[] a, Object a0)
1075 { fillWithArguments(a, pos, a0); return a; }
1076 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1)
1077 { fillWithArguments(a, pos, a0, a1); return a; }
1078 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2)
1079 { fillWithArguments(a, pos, a0, a1, a2); return a; }
1080 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3)
1081 { fillWithArguments(a, pos, a0, a1, a2, a3); return a; }
1082 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1083 Object a4)
1084 { fillWithArguments(a, pos, a0, a1, a2, a3, a4); return a; }
1085 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1086 Object a4, Object a5)
1087 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5); return a; }
1088 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1089 Object a4, Object a5, Object a6)
1090 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6); return a; }
1091 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1092 Object a4, Object a5, Object a6, Object a7)
1093 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7); return a; }
1094 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1095 Object a4, Object a5, Object a6, Object a7,
1096 Object a8)
1097 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8); 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, Object a7,
1100 Object a8, Object a9)
1101 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); return a; }
1102 private static MethodHandle[] makeFillArrays() {
1103 ArrayList<MethodHandle> mhs = new ArrayList<>();
1104 mhs.add(null); // there is no empty fill; at least a0 is required
1105 for (;;) {
1106 MethodHandle mh = findCollector("fillArray", mhs.size(), Object[].class, Integer.class, Object[].class);
1107 if (mh == null) break;
1108 mhs.add(mh);
1109 }
1110 assert(mhs.size() == 11); // current number of methods
1111 return mhs.toArray(new MethodHandle[0]);
1112 }
1113 private static final MethodHandle[] FILL_ARRAYS = makeFillArrays();
1114
1115 private static Object copyAsPrimitiveArray(Wrapper w, Object... boxes) {
1116 Object a = w.makeArray(boxes.length);
1117 w.copyArrayUnboxing(boxes, 0, a, 0, boxes.length);
1118 return a;
1119 }
1120
1121 /** Return a method handle that takes the indicated number of Object
1122 * arguments and returns an Object array of them, as if for varargs.
1123 */
1124 static MethodHandle varargsArray(int nargs) {
1125 MethodHandle mh = ARRAYS[nargs];
1126 if (mh != null) return mh;
1127 mh = findCollector("array", nargs, Object[].class);
1128 if (mh != null) return ARRAYS[nargs] = mh;
1129 mh = buildVarargsArray(Lazy.MH_fillNewArray, Lazy.MH_arrayIdentity, nargs);
1130 assert(assertCorrectArity(mh, nargs));
1131 return ARRAYS[nargs] = mh;
1132 }
1133
1134 private static boolean assertCorrectArity(MethodHandle mh, int arity) {
1135 assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh;
1136 return true;
1137 }
1138
1139 // Array identity function (used as Lazy.MH_arrayIdentity).
1140 static <T> T[] identity(T[] x) {
1141 return x;
1142 }
1143
1144 private static MethodHandle buildVarargsArray(MethodHandle newArray, MethodHandle finisher, int nargs) {
1145 // Build up the result mh as a sequence of fills like this:
1146 // finisher(fill(fill(newArrayWA(23,x1..x10),10,x11..x20),20,x21..x23))
1147 // The various fill(_,10*I,___*[J]) are reusable.
1148 int leftLen = Math.min(nargs, LEFT_ARGS); // absorb some arguments immediately
1149 int rightLen = nargs - leftLen;
1150 MethodHandle leftCollector = newArray.bindTo(nargs);
1151 leftCollector = leftCollector.asCollector(Object[].class, leftLen);
1152 MethodHandle mh = finisher;
1153 if (rightLen > 0) {
1154 MethodHandle rightFiller = fillToRight(LEFT_ARGS + rightLen);
1155 if (mh == Lazy.MH_arrayIdentity)
1156 mh = rightFiller;
1157 else
1158 mh = MethodHandles.collectArguments(mh, 0, rightFiller);
1159 }
1160 if (mh == Lazy.MH_arrayIdentity)
1161 mh = leftCollector;
1162 else
1163 mh = MethodHandles.collectArguments(mh, 0, leftCollector);
1164 return mh;
1165 }
1166
1167 private static final int LEFT_ARGS = (FILL_ARRAYS.length - 1);
1168 private static final MethodHandle[] FILL_ARRAY_TO_RIGHT = new MethodHandle[MAX_ARITY+1];
1169 /** fill_array_to_right(N).invoke(a, argL..arg[N-1])
1170 * fills a[L]..a[N-1] with corresponding arguments,
1171 * and then returns a. The value L is a global constant (LEFT_ARGS).
1172 */
1173 private static MethodHandle fillToRight(int nargs) {
1174 MethodHandle filler = FILL_ARRAY_TO_RIGHT[nargs];
1175 if (filler != null) return filler;
1176 filler = buildFiller(nargs);
1177 assert(assertCorrectArity(filler, nargs - LEFT_ARGS + 1));
1178 return FILL_ARRAY_TO_RIGHT[nargs] = filler;
1179 }
1180 private static MethodHandle buildFiller(int nargs) {
1181 if (nargs <= LEFT_ARGS)
1182 return Lazy.MH_arrayIdentity; // no args to fill; return the array unchanged
1183 // we need room for both mh and a in mh.invoke(a, arg*[nargs])
1184 final int CHUNK = LEFT_ARGS;
1185 int rightLen = nargs % CHUNK;
1186 int midLen = nargs - rightLen;
1187 if (rightLen == 0) {
1188 midLen = nargs - (rightLen = CHUNK);
1189 if (FILL_ARRAY_TO_RIGHT[midLen] == null) {
1190 // build some precursors from left to right
1191 for (int j = LEFT_ARGS % CHUNK; j < midLen; j += CHUNK)
1192 if (j > LEFT_ARGS) fillToRight(j);
1193 }
1194 }
1195 if (midLen < LEFT_ARGS) rightLen = nargs - (midLen = LEFT_ARGS);
1196 assert(rightLen > 0);
1197 MethodHandle midFill = fillToRight(midLen); // recursive fill
1198 MethodHandle rightFill = FILL_ARRAYS[rightLen].bindTo(midLen); // [midLen..nargs-1]
1199 assert(midFill.type().parameterCount() == 1 + midLen - LEFT_ARGS);
1200 assert(rightFill.type().parameterCount() == 1 + rightLen);
1201
1202 // Combine the two fills:
1203 // right(mid(a, x10..x19), x20..x23)
1204 // The final product will look like this:
1205 // right(mid(newArrayLeft(24, x0..x9), x10..x19), x20..x23)
1206 if (midLen == LEFT_ARGS)
1207 return rightFill;
1208 else
1209 return MethodHandles.collectArguments(rightFill, 0, midFill);
1210 }
1211
1212 // Type-polymorphic version of varargs maker.
1213 private static final ClassValue<MethodHandle[]> TYPED_COLLECTORS
1214 = new ClassValue<MethodHandle[]>() {
1215 @Override
1216 protected MethodHandle[] computeValue(Class<?> type) {
1217 return new MethodHandle[256];
1218 }
1219 };
1220
1221 static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM
1222
1223 /** Return a method handle that takes the indicated number of
1224 * typed arguments and returns an array of them.
1225 * The type argument is the array type.
1226 */
1227 static MethodHandle varargsArray(Class<?> arrayType, int nargs) {
1228 Class<?> elemType = arrayType.getComponentType();
1229 if (elemType == null) throw new IllegalArgumentException("not an array: "+arrayType);
1230 // FIXME: Need more special casing and caching here.
1231 if (nargs >= MAX_JVM_ARITY/2 - 1) {
1232 int slots = nargs;
1233 final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH
1234 if (slots <= MAX_ARRAY_SLOTS && elemType.isPrimitive())
1235 slots *= Wrapper.forPrimitiveType(elemType).stackSlots();
1236 if (slots > MAX_ARRAY_SLOTS)
1237 throw new IllegalArgumentException("too many arguments: "+arrayType.getSimpleName()+", length "+nargs);
1238 }
1239 if (elemType == Object.class)
1240 return varargsArray(nargs);
1241 // other cases: primitive arrays, subtypes of Object[]
1242 MethodHandle cache[] = TYPED_COLLECTORS.get(elemType);
1243 MethodHandle mh = nargs < cache.length ? cache[nargs] : null;
1244 if (mh != null) return mh;
1245 if (nargs == 0) {
1246 Object example = java.lang.reflect.Array.newInstance(arrayType.getComponentType(), 0);
1247 mh = MethodHandles.constant(arrayType, example);
1248 } else if (elemType.isPrimitive()) {
1249 MethodHandle builder = Lazy.MH_fillNewArray;
1250 MethodHandle producer = buildArrayProducer(arrayType);
1251 mh = buildVarargsArray(builder, producer, nargs);
1252 } else {
1253 Class<? extends Object[]> objArrayType = arrayType.asSubclass(Object[].class);
1254 Object[] example = Arrays.copyOf(NO_ARGS_ARRAY, 0, objArrayType);
1255 MethodHandle builder = Lazy.MH_fillNewTypedArray.bindTo(example);
1256 MethodHandle producer = Lazy.MH_arrayIdentity; // must be weakly typed
1257 mh = buildVarargsArray(builder, producer, nargs);
1258 }
1259 mh = mh.asType(MethodType.methodType(arrayType, Collections.<Class<?>>nCopies(nargs, elemType)));
1260 assert(assertCorrectArity(mh, nargs));
1261 if (nargs < cache.length)
1262 cache[nargs] = mh;
1263 return mh;
1264 }
1265
1266 private static MethodHandle buildArrayProducer(Class<?> arrayType) {
1267 Class<?> elemType = arrayType.getComponentType();
1268 assert(elemType.isPrimitive());
1269 return Lazy.MH_copyAsPrimitiveArray.bindTo(Wrapper.forPrimitiveType(elemType));
1270 }
1271 }