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.function.Function;
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 mh = makeIntrinsic(mh, (isSetter ? Intrinsic.ARRAY_STORE : Intrinsic.ARRAY_LOAD));
90 // Atomically update accessor cache.
91 synchronized(cache) {
92 if (cache[cacheIndex] == null) {
93 cache[cacheIndex] = mh;
94 } else {
95 // Throw away newly constructed accessor and use cached version.
96 mh = cache[cacheIndex];
97 }
98 }
99 return mh;
100 }
101
102 static final class ArrayAccessor {
103 /// Support for array element access
104 static final int GETTER_INDEX = 0, SETTER_INDEX = 1, INDEX_LIMIT = 2;
105 static final ClassValue<MethodHandle[]> TYPED_ACCESSORS
106 = new ClassValue<MethodHandle[]>() {
107 @Override
108 protected MethodHandle[] computeValue(Class<?> type) {
109 return new MethodHandle[INDEX_LIMIT];
110 }
111 };
112 static final MethodHandle OBJECT_ARRAY_GETTER, OBJECT_ARRAY_SETTER;
113 static {
114 MethodHandle[] cache = TYPED_ACCESSORS.get(Object[].class);
115 cache[GETTER_INDEX] = OBJECT_ARRAY_GETTER = makeIntrinsic(getAccessor(Object[].class, false), Intrinsic.ARRAY_LOAD);
116 cache[SETTER_INDEX] = OBJECT_ARRAY_SETTER = makeIntrinsic(getAccessor(Object[].class, true), Intrinsic.ARRAY_STORE);
117
118 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_GETTER.internalMemberName()));
119 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_SETTER.internalMemberName()));
120 }
121
122 static int getElementI(int[] a, int i) { return a[i]; }
123 static long getElementJ(long[] a, int i) { return a[i]; }
124 static float getElementF(float[] a, int i) { return a[i]; }
125 static double getElementD(double[] a, int i) { return a[i]; }
126 static boolean getElementZ(boolean[] a, int i) { return a[i]; }
127 static byte getElementB(byte[] a, int i) { return a[i]; }
128 static short getElementS(short[] a, int i) { return a[i]; }
129 static char getElementC(char[] a, int i) { return a[i]; }
130 static Object getElementL(Object[] a, int i) { return a[i]; }
131
132 static void setElementI(int[] a, int i, int x) { a[i] = x; }
133 static void setElementJ(long[] a, int i, long x) { a[i] = x; }
134 static void setElementF(float[] a, int i, float x) { a[i] = x; }
135 static void setElementD(double[] a, int i, double x) { a[i] = x; }
136 static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; }
137 static void setElementB(byte[] a, int i, byte x) { a[i] = x; }
138 static void setElementS(short[] a, int i, short x) { a[i] = x; }
139 static void setElementC(char[] a, int i, char x) { a[i] = x; }
140 static void setElementL(Object[] a, int i, Object x) { a[i] = x; }
141
142 static String name(Class<?> arrayClass, boolean isSetter) {
143 Class<?> elemClass = arrayClass.getComponentType();
144 if (elemClass == null) throw newIllegalArgumentException("not an array", arrayClass);
145 return (!isSetter ? "getElement" : "setElement") + Wrapper.basicTypeChar(elemClass);
146 }
147 static MethodType type(Class<?> arrayClass, boolean isSetter) {
148 Class<?> elemClass = arrayClass.getComponentType();
149 Class<?> arrayArgClass = arrayClass;
150 if (!elemClass.isPrimitive()) {
151 arrayArgClass = Object[].class;
152 elemClass = Object.class;
153 }
154 return !isSetter ?
155 MethodType.methodType(elemClass, arrayArgClass, int.class) :
156 MethodType.methodType(void.class, arrayArgClass, int.class, elemClass);
157 }
158 static MethodType correctType(Class<?> arrayClass, boolean isSetter) {
159 Class<?> elemClass = arrayClass.getComponentType();
160 return !isSetter ?
161 MethodType.methodType(elemClass, arrayClass, int.class) :
162 MethodType.methodType(void.class, arrayClass, int.class, elemClass);
163 }
164 static MethodHandle getAccessor(Class<?> arrayClass, boolean isSetter) {
165 String name = name(arrayClass, isSetter);
166 MethodType type = type(arrayClass, isSetter);
167 try {
168 return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type);
169 } catch (ReflectiveOperationException ex) {
170 throw uncaughtException(ex);
171 }
172 }
173 }
174
175 /**
176 * Create a JVM-level adapter method handle to conform the given method
177 * handle to the similar newType, using only pairwise argument conversions.
178 * For each argument, convert incoming argument to the exact type needed.
179 * The argument conversions allowed are casting, boxing and unboxing,
180 * integral widening or narrowing, and floating point widening or narrowing.
181 * @param srcType required call type
182 * @param target original method handle
183 * @param strict if true, only asType conversions are allowed; if false, explicitCastArguments conversions allowed
184 * @param monobox if true, unboxing conversions are assumed to be exactly typed (Integer to int only, not long or double)
185 * @return an adapter to the original handle with the desired new type,
186 * or the original target if the types are already identical
187 * or null if the adaptation cannot be made
188 */
189 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
190 boolean strict, boolean monobox) {
191 MethodType dstType = target.type();
192 if (srcType == dstType)
193 return target;
194 return makePairwiseConvertByEditor(target, srcType, strict, monobox);
195 }
196
197 private static int countNonNull(Object[] array) {
198 int count = 0;
199 for (Object x : array) {
200 if (x != null) ++count;
201 }
202 return count;
203 }
204
205 static MethodHandle makePairwiseConvertByEditor(MethodHandle target, MethodType srcType,
206 boolean strict, boolean monobox) {
207 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
208 int convCount = countNonNull(convSpecs);
209 if (convCount == 0)
210 return target.viewAsType(srcType, strict);
211 MethodType basicSrcType = srcType.basicType();
212 MethodType midType = target.type().basicType();
213 BoundMethodHandle mh = target.rebind();
214 // FIXME: Reduce number of bindings when there is more than one Class conversion.
215 // FIXME: Reduce number of bindings when there are repeated conversions.
216 for (int i = 0; i < convSpecs.length-1; i++) {
217 Object convSpec = convSpecs[i];
218 if (convSpec == null) continue;
219 MethodHandle fn;
220 if (convSpec instanceof Class) {
221 fn = Lazy.MH_castReference.bindTo(convSpec);
222 } else {
223 fn = (MethodHandle) convSpec;
224 }
225 Class<?> newType = basicSrcType.parameterType(i);
226 if (--convCount == 0)
227 midType = srcType;
228 else
229 midType = midType.changeParameterType(i, newType);
230 LambdaForm form2 = mh.editor().filterArgumentForm(1+i, BasicType.basicType(newType));
231 mh = mh.copyWithExtendL(midType, form2, fn);
232 mh = mh.rebind();
233 }
234 Object convSpec = convSpecs[convSpecs.length-1];
235 if (convSpec != null) {
236 MethodHandle fn;
237 if (convSpec instanceof Class) {
238 if (convSpec == void.class)
239 fn = null;
240 else
241 fn = Lazy.MH_castReference.bindTo(convSpec);
242 } else {
243 fn = (MethodHandle) convSpec;
244 }
245 Class<?> newType = basicSrcType.returnType();
246 assert(--convCount == 0);
247 midType = srcType;
248 if (fn != null) {
249 mh = mh.rebind(); // rebind if too complex
250 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), false);
251 mh = mh.copyWithExtendL(midType, form2, fn);
252 } else {
253 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), true);
254 mh = mh.copyWith(midType, form2);
255 }
256 }
257 assert(convCount == 0);
258 assert(mh.type().equals(srcType));
259 return mh;
260 }
261
262 static MethodHandle makePairwiseConvertIndirect(MethodHandle target, MethodType srcType,
263 boolean strict, boolean monobox) {
264 assert(target.type().parameterCount() == srcType.parameterCount());
265 // Calculate extra arguments (temporaries) required in the names array.
266 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
267 final int INARG_COUNT = srcType.parameterCount();
268 int convCount = countNonNull(convSpecs);
269 boolean retConv = (convSpecs[INARG_COUNT] != null);
270 boolean retVoid = srcType.returnType() == void.class;
271 if (retConv && retVoid) {
272 convCount -= 1;
273 retConv = false;
274 }
275
276 final int IN_MH = 0;
277 final int INARG_BASE = 1;
278 final int INARG_LIMIT = INARG_BASE + INARG_COUNT;
279 final int NAME_LIMIT = INARG_LIMIT + convCount + 1;
280 final int RETURN_CONV = (!retConv ? -1 : NAME_LIMIT - 1);
281 final int OUT_CALL = (!retConv ? NAME_LIMIT : RETURN_CONV) - 1;
282 final int RESULT = (retVoid ? -1 : NAME_LIMIT - 1);
283
284 // Now build a LambdaForm.
285 MethodType lambdaType = srcType.basicType().invokerType();
286 Name[] names = arguments(NAME_LIMIT - INARG_LIMIT, lambdaType);
287
288 // Collect the arguments to the outgoing call, maybe with conversions:
289 final int OUTARG_BASE = 0; // target MH is Name.function, name Name.arguments[0]
290 Object[] outArgs = new Object[OUTARG_BASE + INARG_COUNT];
291
292 int nameCursor = INARG_LIMIT;
293 for (int i = 0; i < INARG_COUNT; i++) {
294 Object convSpec = convSpecs[i];
295 if (convSpec == null) {
296 // do nothing: difference is trivial
297 outArgs[OUTARG_BASE + i] = names[INARG_BASE + i];
298 continue;
299 }
300
301 Name conv;
302 if (convSpec instanceof Class) {
303 Class<?> convClass = (Class<?>) convSpec;
304 conv = new Name(Lazy.MH_castReference, convClass, names[INARG_BASE + i]);
305 } else {
306 MethodHandle fn = (MethodHandle) convSpec;
307 conv = new Name(fn, names[INARG_BASE + i]);
308 }
309 assert(names[nameCursor] == null);
310 names[nameCursor++] = conv;
311 assert(outArgs[OUTARG_BASE + i] == null);
312 outArgs[OUTARG_BASE + i] = conv;
313 }
314
315 // Build argument array for the call.
316 assert(nameCursor == OUT_CALL);
317 names[OUT_CALL] = new Name(target, outArgs);
318
319 Object convSpec = convSpecs[INARG_COUNT];
320 if (!retConv) {
321 assert(OUT_CALL == names.length-1);
322 } else {
323 Name conv;
324 if (convSpec == void.class) {
325 conv = new Name(LambdaForm.constantZero(BasicType.basicType(srcType.returnType())));
326 } else if (convSpec instanceof Class) {
327 Class<?> convClass = (Class<?>) convSpec;
328 conv = new Name(Lazy.MH_castReference, convClass, names[OUT_CALL]);
329 } else {
330 MethodHandle fn = (MethodHandle) convSpec;
331 if (fn.type().parameterCount() == 0)
332 conv = new Name(fn); // don't pass retval to void conversion
333 else
334 conv = new Name(fn, names[OUT_CALL]);
335 }
336 assert(names[RETURN_CONV] == null);
337 names[RETURN_CONV] = conv;
338 assert(RETURN_CONV == names.length-1);
339 }
340
341 LambdaForm form = new LambdaForm("convert", lambdaType.parameterCount(), names, RESULT);
342 return SimpleMethodHandle.make(srcType, form);
343 }
344
345 /**
346 * Identity function, with reference cast.
347 * @param t an arbitrary reference type
348 * @param x an arbitrary reference value
349 * @return the same value x
350 */
351 @ForceInline
352 @SuppressWarnings("unchecked")
353 static <T,U> T castReference(Class<? extends T> t, U x) {
354 // inlined Class.cast because we can't ForceInline it
355 if (x != null && !t.isInstance(x))
356 throw newClassCastException(t, x);
357 return (T) x;
358 }
359
360 private static ClassCastException newClassCastException(Class<?> t, Object obj) {
361 return new ClassCastException("Cannot cast " + obj.getClass().getName() + " to " + t.getName());
362 }
363
364 static Object[] computeValueConversions(MethodType srcType, MethodType dstType,
365 boolean strict, boolean monobox) {
366 final int INARG_COUNT = srcType.parameterCount();
367 Object[] convSpecs = new Object[INARG_COUNT+1];
368 for (int i = 0; i <= INARG_COUNT; i++) {
369 boolean isRet = (i == INARG_COUNT);
370 Class<?> src = isRet ? dstType.returnType() : srcType.parameterType(i);
371 Class<?> dst = isRet ? srcType.returnType() : dstType.parameterType(i);
372 if (!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)) {
373 convSpecs[i] = valueConversion(src, dst, strict, monobox);
374 }
375 }
376 return convSpecs;
377 }
378 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
379 boolean strict) {
380 return makePairwiseConvert(target, srcType, strict, /*monobox=*/ false);
381 }
382
383 /**
384 * Find a conversion function from the given source to the given destination.
385 * This conversion function will be used as a LF NamedFunction.
386 * Return a Class object if a simple cast is needed.
387 * Return void.class if void is involved.
388 */
389 static Object valueConversion(Class<?> src, Class<?> dst, boolean strict, boolean monobox) {
390 assert(!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)); // caller responsibility
391 if (dst == void.class)
392 return dst;
393 MethodHandle fn;
394 if (src.isPrimitive()) {
395 if (src == void.class) {
396 return void.class; // caller must recognize this specially
397 } else if (dst.isPrimitive()) {
398 // Examples: int->byte, byte->int, boolean->int (!strict)
399 fn = ValueConversions.convertPrimitive(src, dst);
400 } else {
401 // Examples: int->Integer, boolean->Object, float->Number
402 Wrapper wsrc = Wrapper.forPrimitiveType(src);
403 fn = ValueConversions.boxExact(wsrc);
404 assert(fn.type().parameterType(0) == wsrc.primitiveType());
405 assert(fn.type().returnType() == wsrc.wrapperType());
406 if (!VerifyType.isNullConversion(wsrc.wrapperType(), dst, strict)) {
407 // Corner case, such as int->Long, which will probably fail.
408 MethodType mt = MethodType.methodType(dst, src);
409 if (strict)
410 fn = fn.asType(mt);
411 else
412 fn = MethodHandleImpl.makePairwiseConvert(fn, mt, /*strict=*/ false);
413 }
414 }
415 } else if (dst.isPrimitive()) {
416 Wrapper wdst = Wrapper.forPrimitiveType(dst);
417 if (monobox || src == wdst.wrapperType()) {
418 // Use a strongly-typed unboxer, if possible.
419 fn = ValueConversions.unboxExact(wdst, strict);
420 } else {
421 // Examples: Object->int, Number->int, Comparable->int, Byte->int
422 // must include additional conversions
423 // src must be examined at runtime, to detect Byte, Character, etc.
424 fn = (strict
425 ? ValueConversions.unboxWiden(wdst)
426 : ValueConversions.unboxCast(wdst));
427 }
428 } else {
429 // Simple reference conversion.
430 // Note: Do not check for a class hierarchy relation
431 // between src and dst. In all cases a 'null' argument
432 // will pass the cast conversion.
433 return dst;
434 }
435 assert(fn.type().parameterCount() <= 1) : "pc"+Arrays.asList(src.getSimpleName(), dst.getSimpleName(), fn);
436 return fn;
437 }
438
439 static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
440 MethodType type = target.type();
441 int last = type.parameterCount() - 1;
442 if (type.parameterType(last) != arrayType)
443 target = target.asType(type.changeParameterType(last, arrayType));
444 target = target.asFixedArity(); // make sure this attribute is turned off
445 return new AsVarargsCollector(target, arrayType);
446 }
447
448 private static final class AsVarargsCollector extends DelegatingMethodHandle {
449 private final MethodHandle target;
450 private final Class<?> arrayType;
451 private @Stable MethodHandle asCollectorCache;
452
453 AsVarargsCollector(MethodHandle target, Class<?> arrayType) {
454 this(target.type(), target, arrayType);
455 }
456 AsVarargsCollector(MethodType type, MethodHandle target, Class<?> arrayType) {
457 super(type, target);
458 this.target = target;
459 this.arrayType = arrayType;
460 this.asCollectorCache = target.asCollector(arrayType, 0);
461 }
462
463 @Override
464 public boolean isVarargsCollector() {
465 return true;
466 }
467
468 @Override
469 protected MethodHandle getTarget() {
470 return target;
471 }
472
473 @Override
474 public MethodHandle asFixedArity() {
475 return target;
476 }
477
478 @Override
479 MethodHandle setVarargs(MemberName member) {
480 if (member.isVarargs()) return this;
481 return asFixedArity();
482 }
483
484 @Override
485 public MethodHandle asTypeUncached(MethodType newType) {
486 MethodType type = this.type();
487 int collectArg = type.parameterCount() - 1;
488 int newArity = newType.parameterCount();
489 if (newArity == collectArg+1 &&
490 type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
491 // if arity and trailing parameter are compatible, do normal thing
492 return asTypeCache = asFixedArity().asType(newType);
493 }
494 // check cache
495 MethodHandle acc = asCollectorCache;
496 if (acc != null && acc.type().parameterCount() == newArity)
497 return asTypeCache = acc.asType(newType);
498 // build and cache a collector
499 int arrayLength = newArity - collectArg;
500 MethodHandle collector;
501 try {
502 collector = asFixedArity().asCollector(arrayType, arrayLength);
503 assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
504 } catch (IllegalArgumentException ex) {
505 throw new WrongMethodTypeException("cannot build collector", ex);
506 }
507 asCollectorCache = collector;
508 return asTypeCache = collector.asType(newType);
509 }
510
511 @Override
512 boolean viewAsTypeChecks(MethodType newType, boolean strict) {
513 super.viewAsTypeChecks(newType, true);
514 if (strict) return true;
515 // extra assertion for non-strict checks:
516 assert (type().lastParameterType().getComponentType()
517 .isAssignableFrom(
518 newType.lastParameterType().getComponentType()))
519 : Arrays.asList(this, newType);
520 return true;
521 }
522 }
523
524 /** Factory method: Spread selected argument. */
525 static MethodHandle makeSpreadArguments(MethodHandle target,
526 Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
527 MethodType targetType = target.type();
528
529 for (int i = 0; i < spreadArgCount; i++) {
530 Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i);
531 if (arg == null) arg = Object.class;
532 targetType = targetType.changeParameterType(spreadArgPos + i, arg);
533 }
534 target = target.asType(targetType);
535
536 MethodType srcType = targetType
537 .replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType);
538 // Now build a LambdaForm.
539 MethodType lambdaType = srcType.invokerType();
540 Name[] names = arguments(spreadArgCount + 2, lambdaType);
541 int nameCursor = lambdaType.parameterCount();
542 int[] indexes = new int[targetType.parameterCount()];
543
544 for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) {
545 Class<?> src = lambdaType.parameterType(i);
546 if (i == spreadArgPos) {
547 // Spread the array.
548 MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType);
549 Name array = names[argIndex];
550 names[nameCursor++] = new Name(Lazy.NF_checkSpreadArgument, array, spreadArgCount);
551 for (int j = 0; j < spreadArgCount; i++, j++) {
552 indexes[i] = nameCursor;
553 names[nameCursor++] = new Name(aload, array, j);
554 }
555 } else if (i < indexes.length) {
556 indexes[i] = argIndex;
557 }
558 }
559 assert(nameCursor == names.length-1); // leave room for the final call
560
561 // Build argument array for the call.
562 Name[] targetArgs = new Name[targetType.parameterCount()];
563 for (int i = 0; i < targetType.parameterCount(); i++) {
564 int idx = indexes[i];
565 targetArgs[i] = names[idx];
566 }
567 names[names.length - 1] = new Name(target, (Object[]) targetArgs);
568
569 LambdaForm form = new LambdaForm("spread", lambdaType.parameterCount(), names);
570 return SimpleMethodHandle.make(srcType, form);
571 }
572
573 static void checkSpreadArgument(Object av, int n) {
574 if (av == null) {
575 if (n == 0) return;
576 } else if (av instanceof Object[]) {
577 int len = ((Object[])av).length;
578 if (len == n) return;
579 } else {
580 int len = java.lang.reflect.Array.getLength(av);
581 if (len == n) return;
582 }
583 // fall through to error:
584 throw newIllegalArgumentException("array is not of length "+n);
585 }
586
587 /**
588 * Pre-initialized NamedFunctions for bootstrapping purposes.
589 * Factored in an inner class to delay initialization until first usage.
590 */
591 static class Lazy {
592 private static final Class<?> MHI = MethodHandleImpl.class;
593
594 private static final MethodHandle[] ARRAYS;
595 private static final MethodHandle[] FILL_ARRAYS;
596
597 static final NamedFunction NF_checkSpreadArgument;
598 static final NamedFunction NF_guardWithCatch;
599 static final NamedFunction NF_throwException;
600 static final NamedFunction NF_profileBoolean;
601
602 static final MethodHandle MH_castReference;
603 static final MethodHandle MH_selectAlternative;
604 static final MethodHandle MH_copyAsPrimitiveArray;
605 static final MethodHandle MH_fillNewTypedArray;
606 static final MethodHandle MH_fillNewArray;
607 static final MethodHandle MH_arrayIdentity;
608
609 static {
610 ARRAYS = makeArrays();
611 FILL_ARRAYS = makeFillArrays();
612
613 try {
614 NF_checkSpreadArgument = new NamedFunction(MHI.getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
615 NF_guardWithCatch = new NamedFunction(MHI.getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class,
616 MethodHandle.class, Object[].class));
617 NF_throwException = new NamedFunction(MHI.getDeclaredMethod("throwException", Throwable.class));
618 NF_profileBoolean = new NamedFunction(MHI.getDeclaredMethod("profileBoolean", boolean.class, int[].class));
619
620 NF_checkSpreadArgument.resolve();
621 NF_guardWithCatch.resolve();
622 NF_throwException.resolve();
623 NF_profileBoolean.resolve();
624
625 MH_castReference = IMPL_LOOKUP.findStatic(MHI, "castReference",
626 MethodType.methodType(Object.class, Class.class, Object.class));
627 MH_copyAsPrimitiveArray = IMPL_LOOKUP.findStatic(MHI, "copyAsPrimitiveArray",
628 MethodType.methodType(Object.class, Wrapper.class, Object[].class));
629 MH_arrayIdentity = IMPL_LOOKUP.findStatic(MHI, "identity",
630 MethodType.methodType(Object[].class, Object[].class));
631 MH_fillNewArray = IMPL_LOOKUP.findStatic(MHI, "fillNewArray",
632 MethodType.methodType(Object[].class, Integer.class, Object[].class));
633 MH_fillNewTypedArray = IMPL_LOOKUP.findStatic(MHI, "fillNewTypedArray",
634 MethodType.methodType(Object[].class, Object[].class, Integer.class, Object[].class));
635
636 MH_selectAlternative = makeIntrinsic(
637 IMPL_LOOKUP.findStatic(MHI, "selectAlternative",
638 MethodType.methodType(MethodHandle.class, boolean.class, MethodHandle.class, MethodHandle.class)),
639 Intrinsic.SELECT_ALTERNATIVE);
640 } catch (ReflectiveOperationException ex) {
641 throw newInternalError(ex);
642 }
643 }
644 }
645
646 /** Factory method: Collect or filter selected argument(s). */
647 static MethodHandle makeCollectArguments(MethodHandle target,
648 MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) {
649 MethodType targetType = target.type(); // (a..., c, [b...])=>r
650 MethodType collectorType = collector.type(); // (b...)=>c
651 int collectArgCount = collectorType.parameterCount();
652 Class<?> collectValType = collectorType.returnType();
653 int collectValCount = (collectValType == void.class ? 0 : 1);
654 MethodType srcType = targetType // (a..., [b...])=>r
655 .dropParameterTypes(collectArgPos, collectArgPos+collectValCount);
656 if (!retainOriginalArgs) { // (a..., b...)=>r
657 srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterList());
658 }
659 // in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ]
660 // out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ]
661 // out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ]
662
663 // Now build a LambdaForm.
664 MethodType lambdaType = srcType.invokerType();
665 Name[] names = arguments(2, lambdaType);
666 final int collectNamePos = names.length - 2;
667 final int targetNamePos = names.length - 1;
668
669 Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount);
670 names[collectNamePos] = new Name(collector, (Object[]) collectorArgs);
671
672 // Build argument array for the target.
673 // Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ].
674 // Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ].
675 Name[] targetArgs = new Name[targetType.parameterCount()];
676 int inputArgPos = 1; // incoming LF args to copy to target
677 int targetArgPos = 0; // fill pointer for targetArgs
678 int chunk = collectArgPos; // |headArgs|
679 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
680 inputArgPos += chunk;
681 targetArgPos += chunk;
682 if (collectValType != void.class) {
683 targetArgs[targetArgPos++] = names[collectNamePos];
684 }
685 chunk = collectArgCount;
686 if (retainOriginalArgs) {
687 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
688 targetArgPos += chunk; // optionally pass on the collected chunk
689 }
690 inputArgPos += chunk;
691 chunk = targetArgs.length - targetArgPos; // all the rest
692 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
693 assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also
694 names[targetNamePos] = new Name(target, (Object[]) targetArgs);
695
696 LambdaForm form = new LambdaForm("collect", lambdaType.parameterCount(), names);
697 return SimpleMethodHandle.make(srcType, form);
698 }
699
700 @LambdaForm.Hidden
701 static
702 MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
703 if (testResult) {
704 return target;
705 } else {
706 return fallback;
707 }
708 }
709
710 // Intrinsified by C2. Counters are used during parsing to calculate branch frequencies.
711 @LambdaForm.Hidden
712 static
713 boolean profileBoolean(boolean result, int[] counters) {
714 // Profile is int[2] where [0] and [1] correspond to false and true occurrences respectively.
715 int idx = result ? 1 : 0;
716 try {
717 counters[idx] = Math.addExact(counters[idx], 1);
718 } catch (ArithmeticException e) {
719 // Avoid continuous overflow by halving the problematic count.
720 counters[idx] = counters[idx] / 2;
721 }
722 return result;
723 }
724
725 static
726 MethodHandle makeGuardWithTest(MethodHandle test,
727 MethodHandle target,
728 MethodHandle fallback) {
729 MethodType type = target.type();
730 assert(test.type().equals(type.changeReturnType(boolean.class)) && fallback.type().equals(type));
731 MethodType basicType = type.basicType();
732 LambdaForm form = makeGuardWithTestForm(basicType);
733 BoundMethodHandle mh;
734 try {
735 if (PROFILE_GWT) {
736 int[] counts = new int[2];
737 mh = (BoundMethodHandle)
738 BoundMethodHandle.speciesData_LLLL().constructor().invokeBasic(type, form,
739 (Object) test, (Object) profile(target), (Object) profile(fallback), counts);
740 } else {
741 mh = (BoundMethodHandle)
742 BoundMethodHandle.speciesData_LLL().constructor().invokeBasic(type, form,
743 (Object) test, (Object) profile(target), (Object) profile(fallback));
744 }
745 } catch (Throwable ex) {
746 throw uncaughtException(ex);
747 }
748 assert(mh.type() == type);
749 return mh;
750 }
751
752
753 static
754 MethodHandle profile(MethodHandle target) {
755 if (DONT_INLINE_THRESHOLD >= 0) {
756 return makeBlockInliningWrapper(target);
757 } else {
758 return target;
759 }
760 }
761
762 /**
763 * Block inlining during JIT-compilation of a target method handle if it hasn't been invoked enough times.
764 * Corresponding LambdaForm has @DontInline when compiled into bytecode.
765 */
766 static
767 MethodHandle makeBlockInliningWrapper(MethodHandle target) {
768 LambdaForm lform;
769 if (DONT_INLINE_THRESHOLD > 0) {
770 lform = PRODUCE_BLOCK_INLINING_FORM.apply(target);
771 } else {
772 lform = PRODUCE_REINVOKER_FORM.apply(target);
773 }
774 return new CountingWrapper(target, lform,
775 PRODUCE_BLOCK_INLINING_FORM, PRODUCE_REINVOKER_FORM,
776 DONT_INLINE_THRESHOLD);
777 }
778
779 /** Constructs reinvoker lambda form which block inlining during JIT-compilation for a particular method handle */
780 private static final Function<MethodHandle, LambdaForm> PRODUCE_BLOCK_INLINING_FORM = new Function<MethodHandle, LambdaForm>() {
781 @Override
782 public LambdaForm apply(MethodHandle target) {
783 return DelegatingMethodHandle.makeReinvokerForm(target,
784 MethodTypeForm.LF_DELEGATE_BLOCK_INLINING, CountingWrapper.class, "reinvoker.dontInline", false,
785 DelegatingMethodHandle.NF_getTarget, CountingWrapper.NF_maybeStopCounting);
786 }
787 };
788
789 /** Constructs simple reinvoker lambda form for a particular method handle */
790 private static final Function<MethodHandle, LambdaForm> PRODUCE_REINVOKER_FORM = new Function<MethodHandle, LambdaForm>() {
791 @Override
792 public LambdaForm apply(MethodHandle target) {
793 return DelegatingMethodHandle.makeReinvokerForm(target,
794 MethodTypeForm.LF_DELEGATE, DelegatingMethodHandle.class, DelegatingMethodHandle.NF_getTarget);
795 }
796 };
797
798 /**
799 * Counting method handle. It has 2 states: counting and non-counting.
800 * It is in counting state for the first n invocations and then transitions to non-counting state.
801 * Behavior in counting and non-counting states is determined by lambda forms produced by
802 * countingFormProducer & nonCountingFormProducer respectively.
803 */
804 static class CountingWrapper extends DelegatingMethodHandle {
805 private final MethodHandle target;
806 private int count;
807 private Function<MethodHandle, LambdaForm> countingFormProducer;
808 private Function<MethodHandle, LambdaForm> nonCountingFormProducer;
809 private volatile boolean isCounting;
810
811 private CountingWrapper(MethodHandle target, LambdaForm lform,
812 Function<MethodHandle, LambdaForm> countingFromProducer,
813 Function<MethodHandle, LambdaForm> nonCountingFormProducer,
814 int count) {
815 super(target.type(), lform);
816 this.target = target;
817 this.count = count;
818 this.countingFormProducer = countingFromProducer;
819 this.nonCountingFormProducer = nonCountingFormProducer;
820 this.isCounting = (count > 0);
821 }
822
823 @Hidden
824 @Override
825 protected MethodHandle getTarget() {
826 return target;
827 }
828
829 @Override
830 public MethodHandle asTypeUncached(MethodType newType) {
831 MethodHandle newTarget = target.asType(newType);
832 MethodHandle wrapper;
833 if (isCounting) {
834 LambdaForm lform;
835 lform = countingFormProducer.apply(newTarget);
836 wrapper = new CountingWrapper(newTarget, lform, countingFormProducer, nonCountingFormProducer, DONT_INLINE_THRESHOLD);
837 } else {
838 wrapper = newTarget; // no need for a counting wrapper anymore
839 }
840 return (asTypeCache = wrapper);
841 }
842
843 boolean countDown() {
844 int c = count;
845 if (c <= 1) {
846 // Try to limit number of updates. MethodHandle.updateForm() doesn't guarantee LF update visibility.
847 if (isCounting) {
848 isCounting = false;
849 return true;
850 } else {
851 return false;
852 }
853 } else {
854 count = c - 1;
855 return false;
856 }
857 }
858
859 @Hidden
860 static void maybeStopCounting(Object o1) {
861 CountingWrapper wrapper = (CountingWrapper) o1;
862 if (wrapper.countDown()) {
863 // Reached invocation threshold. Replace counting behavior with a non-counting one.
864 LambdaForm lform = wrapper.nonCountingFormProducer.apply(wrapper.target);
865 lform.compileToBytecode(); // speed up warmup by avoiding LF interpretation again after transition
866 wrapper.updateForm(lform);
867 }
868 }
869
870 static final NamedFunction NF_maybeStopCounting;
871 static {
872 Class<?> THIS_CLASS = CountingWrapper.class;
873 try {
874 NF_maybeStopCounting = new NamedFunction(THIS_CLASS.getDeclaredMethod("maybeStopCounting", Object.class));
875 } catch (ReflectiveOperationException ex) {
876 throw newInternalError(ex);
877 }
878 }
879 }
880
881 static
882 LambdaForm makeGuardWithTestForm(MethodType basicType) {
883 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWT);
884 if (lform != null) return lform;
885 final int THIS_MH = 0; // the BMH_LLL
886 final int ARG_BASE = 1; // start of incoming arguments
887 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
888 int nameCursor = ARG_LIMIT;
889 final int GET_TEST = nameCursor++;
890 final int GET_TARGET = nameCursor++;
891 final int GET_FALLBACK = nameCursor++;
892 final int GET_COUNTERS = PROFILE_GWT ? nameCursor++ : -1;
893 final int CALL_TEST = nameCursor++;
894 final int PROFILE = (GET_COUNTERS != -1) ? nameCursor++ : -1;
895 final int TEST = nameCursor-1; // previous statement: either PROFILE or CALL_TEST
896 final int SELECT_ALT = nameCursor++;
897 final int CALL_TARGET = nameCursor++;
898 assert(CALL_TARGET == SELECT_ALT+1); // must be true to trigger IBG.emitSelectAlternative
899
900 MethodType lambdaType = basicType.invokerType();
901 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
902
903 BoundMethodHandle.SpeciesData data =
904 (GET_COUNTERS != -1) ? BoundMethodHandle.speciesData_LLLL()
905 : BoundMethodHandle.speciesData_LLL();
906 names[THIS_MH] = names[THIS_MH].withConstraint(data);
907 names[GET_TEST] = new Name(data.getterFunction(0), names[THIS_MH]);
908 names[GET_TARGET] = new Name(data.getterFunction(1), names[THIS_MH]);
909 names[GET_FALLBACK] = new Name(data.getterFunction(2), names[THIS_MH]);
910 if (GET_COUNTERS != -1) {
911 names[GET_COUNTERS] = new Name(data.getterFunction(3), names[THIS_MH]);
912 }
913 Object[] invokeArgs = Arrays.copyOfRange(names, 0, ARG_LIMIT, Object[].class);
914
915 // call test
916 MethodType testType = basicType.changeReturnType(boolean.class).basicType();
917 invokeArgs[0] = names[GET_TEST];
918 names[CALL_TEST] = new Name(testType, invokeArgs);
919
920 // profile branch
921 if (PROFILE != -1) {
922 names[PROFILE] = new Name(Lazy.NF_profileBoolean, names[CALL_TEST], names[GET_COUNTERS]);
923 }
924 // call selectAlternative
925 names[SELECT_ALT] = new Name(Lazy.MH_selectAlternative, names[TEST], names[GET_TARGET], names[GET_FALLBACK]);
926
927 // call target or fallback
928 invokeArgs[0] = names[SELECT_ALT];
929 names[CALL_TARGET] = new Name(basicType, invokeArgs);
930
931 lform = new LambdaForm("guard", lambdaType.parameterCount(), names, /*forceInline=*/true);
932
933 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWT, lform);
934 }
935
936 /**
937 * The LambdaForm shape for catchException combinator is the following:
938 * <blockquote><pre>{@code
939 * guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{
940 * t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L);
941 * t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L);
942 * t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L);
943 * t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L);
944 * t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L);
945 * t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L);
946 * t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L);
947 * t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I}
948 * }</pre></blockquote>
949 *
950 * argL0 and argL2 are target and catcher method handles. argL1 is exception class.
951 * argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[]
952 * (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()).
953 *
954 * Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms
955 * among catchException combinators with the same basic type.
956 */
957 private static LambdaForm makeGuardWithCatchForm(MethodType basicType) {
958 MethodType lambdaType = basicType.invokerType();
959
960 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC);
961 if (lform != null) {
962 return lform;
963 }
964 final int THIS_MH = 0; // the BMH_LLLLL
965 final int ARG_BASE = 1; // start of incoming arguments
966 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
967
968 int nameCursor = ARG_LIMIT;
969 final int GET_TARGET = nameCursor++;
970 final int GET_CLASS = nameCursor++;
971 final int GET_CATCHER = nameCursor++;
972 final int GET_COLLECT_ARGS = nameCursor++;
973 final int GET_UNBOX_RESULT = nameCursor++;
974 final int BOXED_ARGS = nameCursor++;
975 final int TRY_CATCH = nameCursor++;
976 final int UNBOX_RESULT = nameCursor++;
977
978 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
979
980 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
981 names[THIS_MH] = names[THIS_MH].withConstraint(data);
982 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
983 names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]);
984 names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]);
985 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]);
986 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]);
987
988 // FIXME: rework argument boxing/result unboxing logic for LF interpretation
989
990 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
991 MethodType collectArgsType = basicType.changeReturnType(Object.class);
992 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
993 Object[] args = new Object[invokeBasic.type().parameterCount()];
994 args[0] = names[GET_COLLECT_ARGS];
995 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
996 names[BOXED_ARGS] = new Name(makeIntrinsic(invokeBasic, Intrinsic.GUARD_WITH_CATCH), args);
997
998 // t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L);
999 Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]};
1000 names[TRY_CATCH] = new Name(Lazy.NF_guardWithCatch, gwcArgs);
1001
1002 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
1003 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
1004 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]};
1005 names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
1006
1007 lform = new LambdaForm("guardWithCatch", lambdaType.parameterCount(), names);
1008
1009 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform);
1010 }
1011
1012 static
1013 MethodHandle makeGuardWithCatch(MethodHandle target,
1014 Class<? extends Throwable> exType,
1015 MethodHandle catcher) {
1016 MethodType type = target.type();
1017 LambdaForm form = makeGuardWithCatchForm(type.basicType());
1018
1019 // Prepare auxiliary method handles used during LambdaForm interpretation.
1020 // Box arguments and wrap them into Object[]: ValueConversions.array().
1021 MethodType varargsType = type.changeReturnType(Object[].class);
1022 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
1023 // Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore().
1024 MethodHandle unboxResult;
1025 Class<?> rtype = type.returnType();
1026 if (rtype.isPrimitive()) {
1027 if (rtype == void.class) {
1028 unboxResult = ValueConversions.ignore();
1029 } else {
1030 Wrapper w = Wrapper.forPrimitiveType(type.returnType());
1031 unboxResult = ValueConversions.unboxExact(w);
1032 }
1033 } else {
1034 unboxResult = MethodHandles.identity(Object.class);
1035 }
1036
1037 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
1038 BoundMethodHandle mh;
1039 try {
1040 mh = (BoundMethodHandle)
1041 data.constructor().invokeBasic(type, form, (Object) target, (Object) exType, (Object) catcher,
1042 (Object) collectArgs, (Object) unboxResult);
1043 } catch (Throwable ex) {
1044 throw uncaughtException(ex);
1045 }
1046 assert(mh.type() == type);
1047 return mh;
1048 }
1049
1050 /**
1051 * Intrinsified during LambdaForm compilation
1052 * (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}).
1053 */
1054 @LambdaForm.Hidden
1055 static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher,
1056 Object... av) throws Throwable {
1057 // Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case.
1058 try {
1059 return target.asFixedArity().invokeWithArguments(av);
1060 } catch (Throwable t) {
1061 if (!exType.isInstance(t)) throw t;
1062 return catcher.asFixedArity().invokeWithArguments(prepend(t, av));
1063 }
1064 }
1065
1066 /** Prepend an element {@code elem} to an {@code array}. */
1067 @LambdaForm.Hidden
1068 private static Object[] prepend(Object elem, Object[] array) {
1069 Object[] newArray = new Object[array.length+1];
1070 newArray[0] = elem;
1071 System.arraycopy(array, 0, newArray, 1, array.length);
1072 return newArray;
1073 }
1074
1075 static
1076 MethodHandle throwException(MethodType type) {
1077 assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
1078 int arity = type.parameterCount();
1079 if (arity > 1) {
1080 MethodHandle mh = throwException(type.dropParameterTypes(1, arity));
1081 mh = MethodHandles.dropArguments(mh, 1, type.parameterList().subList(1, arity));
1082 return mh;
1083 }
1084 return makePairwiseConvert(Lazy.NF_throwException.resolvedHandle(), type, false, true);
1085 }
1086
1087 static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
1088
1089 static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
1090 static MethodHandle fakeMethodHandleInvoke(MemberName method) {
1091 int idx;
1092 assert(method.isMethodHandleInvoke());
1093 switch (method.getName()) {
1094 case "invoke": idx = 0; break;
1095 case "invokeExact": idx = 1; break;
1096 default: throw new InternalError(method.getName());
1097 }
1098 MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
1099 if (mh != null) return mh;
1100 MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
1101 MethodHandle.class, Object[].class);
1102 mh = throwException(type);
1103 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
1104 if (!method.getInvocationType().equals(mh.type()))
1105 throw new InternalError(method.toString());
1106 mh = mh.withInternalMemberName(method, false);
1107 mh = mh.asVarargsCollector(Object[].class);
1108 assert(method.isVarargs());
1109 FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
1110 return mh;
1111 }
1112
1113 /**
1114 * Create an alias for the method handle which, when called,
1115 * appears to be called from the same class loader and protection domain
1116 * as hostClass.
1117 * This is an expensive no-op unless the method which is called
1118 * is sensitive to its caller. A small number of system methods
1119 * are in this category, including Class.forName and Method.invoke.
1120 */
1121 static
1122 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1123 return BindCaller.bindCaller(mh, hostClass);
1124 }
1125
1126 // Put the whole mess into its own nested class.
1127 // That way we can lazily load the code and set up the constants.
1128 private static class BindCaller {
1129 static
1130 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1131 // Do not use this function to inject calls into system classes.
1132 if (hostClass == null
1133 || (hostClass.isArray() ||
1134 hostClass.isPrimitive() ||
1135 hostClass.getName().startsWith("java.") ||
1136 hostClass.getName().startsWith("sun."))) {
1137 throw new InternalError(); // does not happen, and should not anyway
1138 }
1139 // For simplicity, convert mh to a varargs-like method.
1140 MethodHandle vamh = prepareForInvoker(mh);
1141 // Cache the result of makeInjectedInvoker once per argument class.
1142 MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
1143 return restoreToType(bccInvoker.bindTo(vamh), mh, hostClass);
1144 }
1145
1146 private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
1147 Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null);
1148 if (hostClass.getClassLoader() != bcc.getClassLoader())
1149 throw new InternalError(hostClass.getName()+" (CL)");
1150 try {
1151 if (hostClass.getProtectionDomain() != bcc.getProtectionDomain())
1152 throw new InternalError(hostClass.getName()+" (PD)");
1153 } catch (SecurityException ex) {
1154 // Self-check was blocked by security manager. This is OK.
1155 // In fact the whole try body could be turned into an assertion.
1156 }
1157 try {
1158 MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class));
1159 init.invokeExact(); // force initialization of the class
1160 } catch (Throwable ex) {
1161 throw uncaughtException(ex);
1162 }
1163 MethodHandle bccInvoker;
1164 try {
1165 MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1166 bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT);
1167 } catch (ReflectiveOperationException ex) {
1168 throw uncaughtException(ex);
1169 }
1170 // Test the invoker, to ensure that it really injects into the right place.
1171 try {
1172 MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
1173 Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc});
1174 } catch (Throwable ex) {
1175 throw new InternalError(ex);
1176 }
1177 return bccInvoker;
1178 }
1179 private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() {
1180 @Override protected MethodHandle computeValue(Class<?> hostClass) {
1181 return makeInjectedInvoker(hostClass);
1182 }
1183 };
1184
1185 // Adapt mh so that it can be called directly from an injected invoker:
1186 private static MethodHandle prepareForInvoker(MethodHandle mh) {
1187 mh = mh.asFixedArity();
1188 MethodType mt = mh.type();
1189 int arity = mt.parameterCount();
1190 MethodHandle vamh = mh.asType(mt.generic());
1191 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1192 vamh = vamh.asSpreader(Object[].class, arity);
1193 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1194 return vamh;
1195 }
1196
1197 // Undo the adapter effect of prepareForInvoker:
1198 private static MethodHandle restoreToType(MethodHandle vamh,
1199 MethodHandle original,
1200 Class<?> hostClass) {
1201 MethodType type = original.type();
1202 MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount());
1203 MemberName member = original.internalMemberName();
1204 mh = mh.asType(type);
1205 mh = new WrappedMember(mh, type, member, original.isInvokeSpecial(), hostClass);
1206 return mh;
1207 }
1208
1209 private static final MethodHandle MH_checkCallerClass;
1210 static {
1211 final Class<?> THIS_CLASS = BindCaller.class;
1212 assert(checkCallerClass(THIS_CLASS, THIS_CLASS));
1213 try {
1214 MH_checkCallerClass = IMPL_LOOKUP
1215 .findStatic(THIS_CLASS, "checkCallerClass",
1216 MethodType.methodType(boolean.class, Class.class, Class.class));
1217 assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS, THIS_CLASS));
1218 } catch (Throwable ex) {
1219 throw new InternalError(ex);
1220 }
1221 }
1222
1223 @CallerSensitive
1224 private static boolean checkCallerClass(Class<?> expected, Class<?> expected2) {
1225 // This method is called via MH_checkCallerClass and so it's
1226 // correct to ask for the immediate caller here.
1227 Class<?> actual = Reflection.getCallerClass();
1228 if (actual != expected && actual != expected2)
1229 throw new InternalError("found "+actual.getName()+", expected "+expected.getName()
1230 +(expected == expected2 ? "" : ", or else "+expected2.getName()));
1231 return true;
1232 }
1233
1234 private static final byte[] T_BYTES;
1235 static {
1236 final Object[] values = {null};
1237 AccessController.doPrivileged(new PrivilegedAction<Void>() {
1238 public Void run() {
1239 try {
1240 Class<T> tClass = T.class;
1241 String tName = tClass.getName();
1242 String tResource = tName.substring(tName.lastIndexOf('.')+1)+".class";
1243 java.net.URLConnection uconn = tClass.getResource(tResource).openConnection();
1244 int len = uconn.getContentLength();
1245 byte[] bytes = new byte[len];
1246 try (java.io.InputStream str = uconn.getInputStream()) {
1247 int nr = str.read(bytes);
1248 if (nr != len) throw new java.io.IOException(tResource);
1249 }
1250 values[0] = bytes;
1251 } catch (java.io.IOException ex) {
1252 throw new InternalError(ex);
1253 }
1254 return null;
1255 }
1256 });
1257 T_BYTES = (byte[]) values[0];
1258 }
1259
1260 // The following class is used as a template for Unsafe.defineAnonymousClass:
1261 private static class T {
1262 static void init() { } // side effect: initializes this class
1263 static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
1264 return vamh.invokeExact(args);
1265 }
1266 }
1267 }
1268
1269
1270 /** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */
1271 private static final class WrappedMember extends DelegatingMethodHandle {
1272 private final MethodHandle target;
1273 private final MemberName member;
1274 private final Class<?> callerClass;
1275 private final boolean isInvokeSpecial;
1276
1277 private WrappedMember(MethodHandle target, MethodType type,
1278 MemberName member, boolean isInvokeSpecial,
1279 Class<?> callerClass) {
1280 super(type, target);
1281 this.target = target;
1282 this.member = member;
1283 this.callerClass = callerClass;
1284 this.isInvokeSpecial = isInvokeSpecial;
1285 }
1286
1287 @Override
1288 MemberName internalMemberName() {
1289 return member;
1290 }
1291 @Override
1292 Class<?> internalCallerClass() {
1293 return callerClass;
1294 }
1295 @Override
1296 boolean isInvokeSpecial() {
1297 return isInvokeSpecial;
1298 }
1299 @Override
1300 protected MethodHandle getTarget() {
1301 return target;
1302 }
1303 @Override
1304 public MethodHandle asTypeUncached(MethodType newType) {
1305 // This MH is an alias for target, except for the MemberName
1306 // Drop the MemberName if there is any conversion.
1307 return asTypeCache = target.asType(newType);
1308 }
1309 }
1310
1311 static MethodHandle makeWrappedMember(MethodHandle target, MemberName member, boolean isInvokeSpecial) {
1312 if (member.equals(target.internalMemberName()) && isInvokeSpecial == target.isInvokeSpecial())
1313 return target;
1314 return new WrappedMember(target, target.type(), member, isInvokeSpecial, null);
1315 }
1316
1317 /** Intrinsic IDs */
1318 /*non-public*/
1319 enum Intrinsic {
1320 SELECT_ALTERNATIVE,
1321 GUARD_WITH_CATCH,
1322 NEW_ARRAY,
1323 ARRAY_LOAD,
1324 ARRAY_STORE,
1325 IDENTITY,
1326 ZERO,
1327 NONE // no intrinsic associated
1328 }
1329
1330 /** Mark arbitrary method handle as intrinsic.
1331 * InvokerBytecodeGenerator uses this info to produce more efficient bytecode shape. */
1332 private static final class IntrinsicMethodHandle extends DelegatingMethodHandle {
1333 private final MethodHandle target;
1334 private final Intrinsic intrinsicName;
1335
1336 IntrinsicMethodHandle(MethodHandle target, Intrinsic intrinsicName) {
1337 super(target.type(), target);
1338 this.target = target;
1339 this.intrinsicName = intrinsicName;
1340 }
1341
1342 @Override
1343 protected MethodHandle getTarget() {
1344 return target;
1345 }
1346
1347 @Override
1348 Intrinsic intrinsicName() {
1349 return intrinsicName;
1350 }
1351
1352 @Override
1353 public MethodHandle asTypeUncached(MethodType newType) {
1354 // This MH is an alias for target, except for the intrinsic name
1355 // Drop the name if there is any conversion.
1356 return asTypeCache = target.asType(newType);
1357 }
1358
1359 @Override
1360 String internalProperties() {
1361 return super.internalProperties() +
1362 "\n& Intrinsic="+intrinsicName;
1363 }
1364
1365 @Override
1366 public MethodHandle asCollector(Class<?> arrayType, int arrayLength) {
1367 if (intrinsicName == Intrinsic.IDENTITY) {
1368 MethodType resultType = type().asCollectorType(arrayType, arrayLength);
1369 MethodHandle newArray = MethodHandleImpl.varargsArray(arrayType, arrayLength);
1370 return newArray.asType(resultType);
1371 }
1372 return super.asCollector(arrayType, arrayLength);
1373 }
1374 }
1375
1376 static MethodHandle makeIntrinsic(MethodHandle target, Intrinsic intrinsicName) {
1377 if (intrinsicName == target.intrinsicName())
1378 return target;
1379 return new IntrinsicMethodHandle(target, intrinsicName);
1380 }
1381
1382 static MethodHandle makeIntrinsic(MethodType type, LambdaForm form, Intrinsic intrinsicName) {
1383 return new IntrinsicMethodHandle(SimpleMethodHandle.make(type, form), intrinsicName);
1384 }
1385
1386 /// Collection of multiple arguments.
1387
1388 private static MethodHandle findCollector(String name, int nargs, Class<?> rtype, Class<?>... ptypes) {
1389 MethodType type = MethodType.genericMethodType(nargs)
1390 .changeReturnType(rtype)
1391 .insertParameterTypes(0, ptypes);
1392 try {
1393 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, name, type);
1394 } catch (ReflectiveOperationException ex) {
1395 return null;
1396 }
1397 }
1398
1399 private static final Object[] NO_ARGS_ARRAY = {};
1400 private static Object[] makeArray(Object... args) { return args; }
1401 private static Object[] array() { return NO_ARGS_ARRAY; }
1402 private static Object[] array(Object a0)
1403 { return makeArray(a0); }
1404 private static Object[] array(Object a0, Object a1)
1405 { return makeArray(a0, a1); }
1406 private static Object[] array(Object a0, Object a1, Object a2)
1407 { return makeArray(a0, a1, a2); }
1408 private static Object[] array(Object a0, Object a1, Object a2, Object a3)
1409 { return makeArray(a0, a1, a2, a3); }
1410 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1411 Object a4)
1412 { return makeArray(a0, a1, a2, a3, a4); }
1413 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1414 Object a4, Object a5)
1415 { return makeArray(a0, a1, a2, a3, a4, a5); }
1416 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1417 Object a4, Object a5, Object a6)
1418 { return makeArray(a0, a1, a2, a3, a4, a5, a6); }
1419 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1420 Object a4, Object a5, Object a6, Object a7)
1421 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7); }
1422 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1423 Object a4, Object a5, Object a6, Object a7,
1424 Object a8)
1425 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8); }
1426 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1427 Object a4, Object a5, Object a6, Object a7,
1428 Object a8, Object a9)
1429 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
1430
1431 private static final int ARRAYS_COUNT = 11;
1432
1433 private static MethodHandle[] makeArrays() {
1434 MethodHandle[] mhs = new MethodHandle[MAX_ARITY + 1];
1435 for (int i = 0; i < ARRAYS_COUNT; i++) {
1436 MethodHandle mh = findCollector("array", i, Object[].class);
1437 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1438 mhs[i] = mh;
1439 }
1440 assert(assertArrayMethodCount(mhs));
1441 return mhs;
1442 }
1443
1444 private static boolean assertArrayMethodCount(MethodHandle[] mhs) {
1445 assert(findCollector("array", ARRAYS_COUNT, Object[].class) == null);
1446 for (int i = 0; i < ARRAYS_COUNT; i++) {
1447 assert(mhs[i] != null);
1448 }
1449 return true;
1450 }
1451
1452 // filling versions of the above:
1453 // using Integer len instead of int len and no varargs to avoid bootstrapping problems
1454 private static Object[] fillNewArray(Integer len, Object[] /*not ...*/ args) {
1455 Object[] a = new Object[len];
1456 fillWithArguments(a, 0, args);
1457 return a;
1458 }
1459 private static Object[] fillNewTypedArray(Object[] example, Integer len, Object[] /*not ...*/ args) {
1460 Object[] a = Arrays.copyOf(example, len);
1461 assert(a.getClass() != Object[].class);
1462 fillWithArguments(a, 0, args);
1463 return a;
1464 }
1465 private static void fillWithArguments(Object[] a, int pos, Object... args) {
1466 System.arraycopy(args, 0, a, pos, args.length);
1467 }
1468 // using Integer pos instead of int pos to avoid bootstrapping problems
1469 private static Object[] fillArray(Integer pos, Object[] a, Object a0)
1470 { fillWithArguments(a, pos, a0); return a; }
1471 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1)
1472 { fillWithArguments(a, pos, a0, a1); return a; }
1473 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2)
1474 { fillWithArguments(a, pos, a0, a1, a2); return a; }
1475 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3)
1476 { fillWithArguments(a, pos, a0, a1, a2, a3); return a; }
1477 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1478 Object a4)
1479 { fillWithArguments(a, pos, a0, a1, a2, a3, a4); return a; }
1480 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1481 Object a4, Object a5)
1482 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5); return a; }
1483 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1484 Object a4, Object a5, Object a6)
1485 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6); return a; }
1486 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1487 Object a4, Object a5, Object a6, Object a7)
1488 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7); return a; }
1489 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1490 Object a4, Object a5, Object a6, Object a7,
1491 Object a8)
1492 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8); return a; }
1493 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1494 Object a4, Object a5, Object a6, Object a7,
1495 Object a8, Object a9)
1496 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); return a; }
1497
1498 private static final int FILL_ARRAYS_COUNT = 11; // current number of fillArray methods
1499
1500 private static MethodHandle[] makeFillArrays() {
1501 MethodHandle[] mhs = new MethodHandle[FILL_ARRAYS_COUNT];
1502 mhs[0] = null; // there is no empty fill; at least a0 is required
1503 for (int i = 1; i < FILL_ARRAYS_COUNT; i++) {
1504 MethodHandle mh = findCollector("fillArray", i, Object[].class, Integer.class, Object[].class);
1505 mhs[i] = mh;
1506 }
1507 assert(assertFillArrayMethodCount(mhs));
1508 return mhs;
1509 }
1510
1511 private static boolean assertFillArrayMethodCount(MethodHandle[] mhs) {
1512 assert(findCollector("fillArray", FILL_ARRAYS_COUNT, Object[].class, Integer.class, Object[].class) == null);
1513 for (int i = 1; i < FILL_ARRAYS_COUNT; i++) {
1514 assert(mhs[i] != null);
1515 }
1516 return true;
1517 }
1518
1519 private static Object copyAsPrimitiveArray(Wrapper w, Object... boxes) {
1520 Object a = w.makeArray(boxes.length);
1521 w.copyArrayUnboxing(boxes, 0, a, 0, boxes.length);
1522 return a;
1523 }
1524
1525 /** Return a method handle that takes the indicated number of Object
1526 * arguments and returns an Object array of them, as if for varargs.
1527 */
1528 static MethodHandle varargsArray(int nargs) {
1529 MethodHandle mh = Lazy.ARRAYS[nargs];
1530 if (mh != null) return mh;
1531 mh = buildVarargsArray(Lazy.MH_fillNewArray, Lazy.MH_arrayIdentity, nargs);
1532 assert(assertCorrectArity(mh, nargs));
1533 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1534 return Lazy.ARRAYS[nargs] = mh;
1535 }
1536
1537 private static boolean assertCorrectArity(MethodHandle mh, int arity) {
1538 assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh;
1539 return true;
1540 }
1541
1542 // Array identity function (used as Lazy.MH_arrayIdentity).
1543 static <T> T[] identity(T[] x) {
1544 return x;
1545 }
1546
1547 private static MethodHandle buildVarargsArray(MethodHandle newArray, MethodHandle finisher, int nargs) {
1548 // Build up the result mh as a sequence of fills like this:
1549 // finisher(fill(fill(newArrayWA(23,x1..x10),10,x11..x20),20,x21..x23))
1550 // The various fill(_,10*I,___*[J]) are reusable.
1551 int leftLen = Math.min(nargs, LEFT_ARGS); // absorb some arguments immediately
1552 int rightLen = nargs - leftLen;
1553 MethodHandle leftCollector = newArray.bindTo(nargs);
1554 leftCollector = leftCollector.asCollector(Object[].class, leftLen);
1555 MethodHandle mh = finisher;
1556 if (rightLen > 0) {
1557 MethodHandle rightFiller = fillToRight(LEFT_ARGS + rightLen);
1558 if (mh == Lazy.MH_arrayIdentity)
1559 mh = rightFiller;
1560 else
1561 mh = MethodHandles.collectArguments(mh, 0, rightFiller);
1562 }
1563 if (mh == Lazy.MH_arrayIdentity)
1564 mh = leftCollector;
1565 else
1566 mh = MethodHandles.collectArguments(mh, 0, leftCollector);
1567 return mh;
1568 }
1569
1570 private static final int LEFT_ARGS = FILL_ARRAYS_COUNT - 1;
1571 private static final MethodHandle[] FILL_ARRAY_TO_RIGHT = new MethodHandle[MAX_ARITY+1];
1572 /** fill_array_to_right(N).invoke(a, argL..arg[N-1])
1573 * fills a[L]..a[N-1] with corresponding arguments,
1574 * and then returns a. The value L is a global constant (LEFT_ARGS).
1575 */
1576 private static MethodHandle fillToRight(int nargs) {
1577 MethodHandle filler = FILL_ARRAY_TO_RIGHT[nargs];
1578 if (filler != null) return filler;
1579 filler = buildFiller(nargs);
1580 assert(assertCorrectArity(filler, nargs - LEFT_ARGS + 1));
1581 return FILL_ARRAY_TO_RIGHT[nargs] = filler;
1582 }
1583 private static MethodHandle buildFiller(int nargs) {
1584 if (nargs <= LEFT_ARGS)
1585 return Lazy.MH_arrayIdentity; // no args to fill; return the array unchanged
1586 // we need room for both mh and a in mh.invoke(a, arg*[nargs])
1587 final int CHUNK = LEFT_ARGS;
1588 int rightLen = nargs % CHUNK;
1589 int midLen = nargs - rightLen;
1590 if (rightLen == 0) {
1591 midLen = nargs - (rightLen = CHUNK);
1592 if (FILL_ARRAY_TO_RIGHT[midLen] == null) {
1593 // build some precursors from left to right
1594 for (int j = LEFT_ARGS % CHUNK; j < midLen; j += CHUNK)
1595 if (j > LEFT_ARGS) fillToRight(j);
1596 }
1597 }
1598 if (midLen < LEFT_ARGS) rightLen = nargs - (midLen = LEFT_ARGS);
1599 assert(rightLen > 0);
1600 MethodHandle midFill = fillToRight(midLen); // recursive fill
1601 MethodHandle rightFill = Lazy.FILL_ARRAYS[rightLen].bindTo(midLen); // [midLen..nargs-1]
1602 assert(midFill.type().parameterCount() == 1 + midLen - LEFT_ARGS);
1603 assert(rightFill.type().parameterCount() == 1 + rightLen);
1604
1605 // Combine the two fills:
1606 // right(mid(a, x10..x19), x20..x23)
1607 // The final product will look like this:
1608 // right(mid(newArrayLeft(24, x0..x9), x10..x19), x20..x23)
1609 if (midLen == LEFT_ARGS)
1610 return rightFill;
1611 else
1612 return MethodHandles.collectArguments(rightFill, 0, midFill);
1613 }
1614
1615 // Type-polymorphic version of varargs maker.
1616 private static final ClassValue<MethodHandle[]> TYPED_COLLECTORS
1617 = new ClassValue<MethodHandle[]>() {
1618 @Override
1619 protected MethodHandle[] computeValue(Class<?> type) {
1620 return new MethodHandle[256];
1621 }
1622 };
1623
1624 static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM
1625
1626 /** Return a method handle that takes the indicated number of
1627 * typed arguments and returns an array of them.
1628 * The type argument is the array type.
1629 */
1630 static MethodHandle varargsArray(Class<?> arrayType, int nargs) {
1631 Class<?> elemType = arrayType.getComponentType();
1632 if (elemType == null) throw new IllegalArgumentException("not an array: "+arrayType);
1633 // FIXME: Need more special casing and caching here.
1634 if (nargs >= MAX_JVM_ARITY/2 - 1) {
1635 int slots = nargs;
1636 final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH
1637 if (slots <= MAX_ARRAY_SLOTS && elemType.isPrimitive())
1638 slots *= Wrapper.forPrimitiveType(elemType).stackSlots();
1639 if (slots > MAX_ARRAY_SLOTS)
1640 throw new IllegalArgumentException("too many arguments: "+arrayType.getSimpleName()+", length "+nargs);
1641 }
1642 if (elemType == Object.class)
1643 return varargsArray(nargs);
1644 // other cases: primitive arrays, subtypes of Object[]
1645 MethodHandle cache[] = TYPED_COLLECTORS.get(elemType);
1646 MethodHandle mh = nargs < cache.length ? cache[nargs] : null;
1647 if (mh != null) return mh;
1648 if (nargs == 0) {
1649 Object example = java.lang.reflect.Array.newInstance(arrayType.getComponentType(), 0);
1650 mh = MethodHandles.constant(arrayType, example);
1651 } else if (elemType.isPrimitive()) {
1652 MethodHandle builder = Lazy.MH_fillNewArray;
1653 MethodHandle producer = buildArrayProducer(arrayType);
1654 mh = buildVarargsArray(builder, producer, nargs);
1655 } else {
1656 Class<? extends Object[]> objArrayType = arrayType.asSubclass(Object[].class);
1657 Object[] example = Arrays.copyOf(NO_ARGS_ARRAY, 0, objArrayType);
1658 MethodHandle builder = Lazy.MH_fillNewTypedArray.bindTo(example);
1659 MethodHandle producer = Lazy.MH_arrayIdentity; // must be weakly typed
1660 mh = buildVarargsArray(builder, producer, nargs);
1661 }
1662 mh = mh.asType(MethodType.methodType(arrayType, Collections.<Class<?>>nCopies(nargs, elemType)));
1663 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1664 assert(assertCorrectArity(mh, nargs));
1665 if (nargs < cache.length)
1666 cache[nargs] = mh;
1667 return mh;
1668 }
1669
1670 private static MethodHandle buildArrayProducer(Class<?> arrayType) {
1671 Class<?> elemType = arrayType.getComponentType();
1672 assert(elemType.isPrimitive());
1673 return Lazy.MH_copyAsPrimitiveArray.bindTo(Wrapper.forPrimitiveType(elemType));
1674 }
1675
1676 /*non-public*/ static void assertSame(Object mh1, Object mh2) {
1677 if (mh1 != mh2) {
1678 String msg = String.format("mh1 != mh2: mh1 = %s (form: %s); mh2 = %s (form: %s)",
1679 mh1, ((MethodHandle)mh1).form,
1680 mh2, ((MethodHandle)mh2).form);
1681 throw newInternalError(msg);
1682 }
1683 }
1684 }