1 /*
2 * Copyright (c) 2008, 2015, 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 jdk.internal.HotSpotIntrinsicCandidate;
40 import sun.reflect.CallerSensitive;
41 import sun.reflect.Reflection;
42 import static java.lang.invoke.LambdaForm.*;
43 import static java.lang.invoke.MethodHandleStatics.*;
44 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
45
46 /**
47 * Trusted implementation code for MethodHandle.
48 * @author jrose
49 */
50 /*non-public*/ abstract class MethodHandleImpl {
51 // Do not adjust this except for special platforms:
52 private static final int MAX_ARITY;
53 static {
54 final Object[] values = { 255 };
55 AccessController.doPrivileged(new PrivilegedAction<>() {
56 @Override
57 public Void run() {
58 values[0] = Integer.getInteger(MethodHandleImpl.class.getName()+".MAX_ARITY", 255);
59 return null;
60 }
61 });
62 MAX_ARITY = (Integer) values[0];
63 }
64
65 /// Factory methods to create method handles:
66
67 static void initStatics() {
68 // Trigger selected static initializations.
69 MemberName.Factory.INSTANCE.getClass();
70 }
71
72 static MethodHandle makeArrayElementAccessor(Class<?> arrayClass, boolean isSetter) {
73 if (arrayClass == Object[].class)
74 return (isSetter ? ArrayAccessor.OBJECT_ARRAY_SETTER : ArrayAccessor.OBJECT_ARRAY_GETTER);
75 if (!arrayClass.isArray())
76 throw newIllegalArgumentException("not an array: "+arrayClass);
77 MethodHandle[] cache = ArrayAccessor.TYPED_ACCESSORS.get(arrayClass);
78 int cacheIndex = (isSetter ? ArrayAccessor.SETTER_INDEX : ArrayAccessor.GETTER_INDEX);
79 MethodHandle mh = cache[cacheIndex];
80 if (mh != null) return mh;
81 mh = ArrayAccessor.getAccessor(arrayClass, isSetter);
82 MethodType correctType = ArrayAccessor.correctType(arrayClass, isSetter);
83 if (mh.type() != correctType) {
84 assert(mh.type().parameterType(0) == Object[].class);
85 assert((isSetter ? mh.type().parameterType(2) : mh.type().returnType()) == Object.class);
86 assert(isSetter || correctType.parameterType(0).getComponentType() == correctType.returnType());
87 // safe to view non-strictly, because element type follows from array type
88 mh = mh.viewAsType(correctType, false);
89 }
90 mh = makeIntrinsic(mh, (isSetter ? Intrinsic.ARRAY_STORE : Intrinsic.ARRAY_LOAD));
91 // Atomically update accessor cache.
92 synchronized(cache) {
93 if (cache[cacheIndex] == null) {
94 cache[cacheIndex] = mh;
95 } else {
96 // Throw away newly constructed accessor and use cached version.
97 mh = cache[cacheIndex];
98 }
99 }
100 return mh;
101 }
102
103 static final class ArrayAccessor {
104 /// Support for array element access
105 static final int GETTER_INDEX = 0, SETTER_INDEX = 1, INDEX_LIMIT = 2;
106 static final ClassValue<MethodHandle[]> TYPED_ACCESSORS
107 = new ClassValue<MethodHandle[]>() {
108 @Override
109 protected MethodHandle[] computeValue(Class<?> type) {
110 return new MethodHandle[INDEX_LIMIT];
111 }
112 };
113 static final MethodHandle OBJECT_ARRAY_GETTER, OBJECT_ARRAY_SETTER;
114 static {
115 MethodHandle[] cache = TYPED_ACCESSORS.get(Object[].class);
116 cache[GETTER_INDEX] = OBJECT_ARRAY_GETTER = makeIntrinsic(getAccessor(Object[].class, false), Intrinsic.ARRAY_LOAD);
117 cache[SETTER_INDEX] = OBJECT_ARRAY_SETTER = makeIntrinsic(getAccessor(Object[].class, true), Intrinsic.ARRAY_STORE);
118
119 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_GETTER.internalMemberName()));
120 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_SETTER.internalMemberName()));
121 }
122
123 static int getElementI(int[] a, int i) { return a[i]; }
124 static long getElementJ(long[] a, int i) { return a[i]; }
125 static float getElementF(float[] a, int i) { return a[i]; }
126 static double getElementD(double[] a, int i) { return a[i]; }
127 static boolean getElementZ(boolean[] a, int i) { return a[i]; }
128 static byte getElementB(byte[] a, int i) { return a[i]; }
129 static short getElementS(short[] a, int i) { return a[i]; }
130 static char getElementC(char[] a, int i) { return a[i]; }
131 static Object getElementL(Object[] a, int i) { return a[i]; }
132
133 static void setElementI(int[] a, int i, int x) { a[i] = x; }
134 static void setElementJ(long[] a, int i, long x) { a[i] = x; }
135 static void setElementF(float[] a, int i, float x) { a[i] = x; }
136 static void setElementD(double[] a, int i, double x) { a[i] = x; }
137 static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; }
138 static void setElementB(byte[] a, int i, byte x) { a[i] = x; }
139 static void setElementS(short[] a, int i, short x) { a[i] = x; }
140 static void setElementC(char[] a, int i, char x) { a[i] = x; }
141 static void setElementL(Object[] a, int i, Object x) { a[i] = x; }
142
143 static String name(Class<?> arrayClass, boolean isSetter) {
144 Class<?> elemClass = arrayClass.getComponentType();
145 if (elemClass == null) throw newIllegalArgumentException("not an array", arrayClass);
146 return (!isSetter ? "getElement" : "setElement") + Wrapper.basicTypeChar(elemClass);
147 }
148 static MethodType type(Class<?> arrayClass, boolean isSetter) {
149 Class<?> elemClass = arrayClass.getComponentType();
150 Class<?> arrayArgClass = arrayClass;
151 if (!elemClass.isPrimitive()) {
152 arrayArgClass = Object[].class;
153 elemClass = Object.class;
154 }
155 return !isSetter ?
156 MethodType.methodType(elemClass, arrayArgClass, int.class) :
157 MethodType.methodType(void.class, arrayArgClass, int.class, elemClass);
158 }
159 static MethodType correctType(Class<?> arrayClass, boolean isSetter) {
160 Class<?> elemClass = arrayClass.getComponentType();
161 return !isSetter ?
162 MethodType.methodType(elemClass, arrayClass, int.class) :
163 MethodType.methodType(void.class, arrayClass, int.class, elemClass);
164 }
165 static MethodHandle getAccessor(Class<?> arrayClass, boolean isSetter) {
166 String name = name(arrayClass, isSetter);
167 MethodType type = type(arrayClass, isSetter);
168 try {
169 return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type);
170 } catch (ReflectiveOperationException ex) {
171 throw uncaughtException(ex);
172 }
173 }
174 }
175
176 /**
177 * Create a JVM-level adapter method handle to conform the given method
178 * handle to the similar newType, using only pairwise argument conversions.
179 * For each argument, convert incoming argument to the exact type needed.
180 * The argument conversions allowed are casting, boxing and unboxing,
181 * integral widening or narrowing, and floating point widening or narrowing.
182 * @param srcType required call type
183 * @param target original method handle
184 * @param strict if true, only asType conversions are allowed; if false, explicitCastArguments conversions allowed
185 * @param monobox if true, unboxing conversions are assumed to be exactly typed (Integer to int only, not long or double)
186 * @return an adapter to the original handle with the desired new type,
187 * or the original target if the types are already identical
188 * or null if the adaptation cannot be made
189 */
190 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
191 boolean strict, boolean monobox) {
192 MethodType dstType = target.type();
193 if (srcType == dstType)
194 return target;
195 return makePairwiseConvertByEditor(target, srcType, strict, monobox);
196 }
197
198 private static int countNonNull(Object[] array) {
199 int count = 0;
200 for (Object x : array) {
201 if (x != null) ++count;
202 }
203 return count;
204 }
205
206 static MethodHandle makePairwiseConvertByEditor(MethodHandle target, MethodType srcType,
207 boolean strict, boolean monobox) {
208 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
209 int convCount = countNonNull(convSpecs);
210 if (convCount == 0)
211 return target.viewAsType(srcType, strict);
212 MethodType basicSrcType = srcType.basicType();
213 MethodType midType = target.type().basicType();
214 BoundMethodHandle mh = target.rebind();
215 // FIXME: Reduce number of bindings when there is more than one Class conversion.
216 // FIXME: Reduce number of bindings when there are repeated conversions.
217 for (int i = 0; i < convSpecs.length-1; i++) {
218 Object convSpec = convSpecs[i];
219 if (convSpec == null) continue;
220 MethodHandle fn;
221 if (convSpec instanceof Class) {
222 fn = Lazy.MH_cast.bindTo(convSpec);
223 } else {
224 fn = (MethodHandle) convSpec;
225 }
226 Class<?> newType = basicSrcType.parameterType(i);
227 if (--convCount == 0)
228 midType = srcType;
229 else
230 midType = midType.changeParameterType(i, newType);
231 LambdaForm form2 = mh.editor().filterArgumentForm(1+i, BasicType.basicType(newType));
232 mh = mh.copyWithExtendL(midType, form2, fn);
233 mh = mh.rebind();
234 }
235 Object convSpec = convSpecs[convSpecs.length-1];
236 if (convSpec != null) {
237 MethodHandle fn;
238 if (convSpec instanceof Class) {
239 if (convSpec == void.class)
240 fn = null;
241 else
242 fn = Lazy.MH_cast.bindTo(convSpec);
243 } else {
244 fn = (MethodHandle) convSpec;
245 }
246 Class<?> newType = basicSrcType.returnType();
247 assert(--convCount == 0);
248 midType = srcType;
249 if (fn != null) {
250 mh = mh.rebind(); // rebind if too complex
251 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), false);
252 mh = mh.copyWithExtendL(midType, form2, fn);
253 } else {
254 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), true);
255 mh = mh.copyWith(midType, form2);
256 }
257 }
258 assert(convCount == 0);
259 assert(mh.type().equals(srcType));
260 return mh;
261 }
262
263 static MethodHandle makePairwiseConvertIndirect(MethodHandle target, MethodType srcType,
264 boolean strict, boolean monobox) {
265 assert(target.type().parameterCount() == srcType.parameterCount());
266 // Calculate extra arguments (temporaries) required in the names array.
267 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
268 final int INARG_COUNT = srcType.parameterCount();
269 int convCount = countNonNull(convSpecs);
270 boolean retConv = (convSpecs[INARG_COUNT] != null);
271 boolean retVoid = srcType.returnType() == void.class;
272 if (retConv && retVoid) {
273 convCount -= 1;
274 retConv = false;
275 }
276
277 final int IN_MH = 0;
278 final int INARG_BASE = 1;
279 final int INARG_LIMIT = INARG_BASE + INARG_COUNT;
280 final int NAME_LIMIT = INARG_LIMIT + convCount + 1;
281 final int RETURN_CONV = (!retConv ? -1 : NAME_LIMIT - 1);
282 final int OUT_CALL = (!retConv ? NAME_LIMIT : RETURN_CONV) - 1;
283 final int RESULT = (retVoid ? -1 : NAME_LIMIT - 1);
284
285 // Now build a LambdaForm.
286 MethodType lambdaType = srcType.basicType().invokerType();
287 Name[] names = arguments(NAME_LIMIT - INARG_LIMIT, lambdaType);
288
289 // Collect the arguments to the outgoing call, maybe with conversions:
290 final int OUTARG_BASE = 0; // target MH is Name.function, name Name.arguments[0]
291 Object[] outArgs = new Object[OUTARG_BASE + INARG_COUNT];
292
293 int nameCursor = INARG_LIMIT;
294 for (int i = 0; i < INARG_COUNT; i++) {
295 Object convSpec = convSpecs[i];
296 if (convSpec == null) {
297 // do nothing: difference is trivial
298 outArgs[OUTARG_BASE + i] = names[INARG_BASE + i];
299 continue;
300 }
301
302 Name conv;
303 if (convSpec instanceof Class) {
304 Class<?> convClass = (Class<?>) convSpec;
305 conv = new Name(Lazy.MH_cast, convClass, names[INARG_BASE + i]);
306 } else {
307 MethodHandle fn = (MethodHandle) convSpec;
308 conv = new Name(fn, names[INARG_BASE + i]);
309 }
310 assert(names[nameCursor] == null);
311 names[nameCursor++] = conv;
312 assert(outArgs[OUTARG_BASE + i] == null);
313 outArgs[OUTARG_BASE + i] = conv;
314 }
315
316 // Build argument array for the call.
317 assert(nameCursor == OUT_CALL);
318 names[OUT_CALL] = new Name(target, outArgs);
319
320 Object convSpec = convSpecs[INARG_COUNT];
321 if (!retConv) {
322 assert(OUT_CALL == names.length-1);
323 } else {
324 Name conv;
325 if (convSpec == void.class) {
326 conv = new Name(LambdaForm.constantZero(BasicType.basicType(srcType.returnType())));
327 } else if (convSpec instanceof Class) {
328 Class<?> convClass = (Class<?>) convSpec;
329 conv = new Name(Lazy.MH_cast, convClass, names[OUT_CALL]);
330 } else {
331 MethodHandle fn = (MethodHandle) convSpec;
332 if (fn.type().parameterCount() == 0)
333 conv = new Name(fn); // don't pass retval to void conversion
334 else
335 conv = new Name(fn, names[OUT_CALL]);
336 }
337 assert(names[RETURN_CONV] == null);
338 names[RETURN_CONV] = conv;
339 assert(RETURN_CONV == names.length-1);
340 }
341
342 LambdaForm form = new LambdaForm("convert", lambdaType.parameterCount(), names, RESULT);
343 return SimpleMethodHandle.make(srcType, form);
344 }
345
346 static Object[] computeValueConversions(MethodType srcType, MethodType dstType,
347 boolean strict, boolean monobox) {
348 final int INARG_COUNT = srcType.parameterCount();
349 Object[] convSpecs = new Object[INARG_COUNT+1];
350 for (int i = 0; i <= INARG_COUNT; i++) {
351 boolean isRet = (i == INARG_COUNT);
352 Class<?> src = isRet ? dstType.returnType() : srcType.parameterType(i);
353 Class<?> dst = isRet ? srcType.returnType() : dstType.parameterType(i);
354 if (!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)) {
355 convSpecs[i] = valueConversion(src, dst, strict, monobox);
356 }
357 }
358 return convSpecs;
359 }
360 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
361 boolean strict) {
362 return makePairwiseConvert(target, srcType, strict, /*monobox=*/ false);
363 }
364
365 /**
366 * Find a conversion function from the given source to the given destination.
367 * This conversion function will be used as a LF NamedFunction.
368 * Return a Class object if a simple cast is needed.
369 * Return void.class if void is involved.
370 */
371 static Object valueConversion(Class<?> src, Class<?> dst, boolean strict, boolean monobox) {
372 assert(!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)); // caller responsibility
373 if (dst == void.class)
374 return dst;
375 MethodHandle fn;
376 if (src.isPrimitive()) {
377 if (src == void.class) {
378 return void.class; // caller must recognize this specially
379 } else if (dst.isPrimitive()) {
380 // Examples: int->byte, byte->int, boolean->int (!strict)
381 fn = ValueConversions.convertPrimitive(src, dst);
382 } else {
383 // Examples: int->Integer, boolean->Object, float->Number
384 Wrapper wsrc = Wrapper.forPrimitiveType(src);
385 fn = ValueConversions.boxExact(wsrc);
386 assert(fn.type().parameterType(0) == wsrc.primitiveType());
387 assert(fn.type().returnType() == wsrc.wrapperType());
388 if (!VerifyType.isNullConversion(wsrc.wrapperType(), dst, strict)) {
389 // Corner case, such as int->Long, which will probably fail.
390 MethodType mt = MethodType.methodType(dst, src);
391 if (strict)
392 fn = fn.asType(mt);
393 else
394 fn = MethodHandleImpl.makePairwiseConvert(fn, mt, /*strict=*/ false);
395 }
396 }
397 } else if (dst.isPrimitive()) {
398 Wrapper wdst = Wrapper.forPrimitiveType(dst);
399 if (monobox || src == wdst.wrapperType()) {
400 // Use a strongly-typed unboxer, if possible.
401 fn = ValueConversions.unboxExact(wdst, strict);
402 } else {
403 // Examples: Object->int, Number->int, Comparable->int, Byte->int
404 // must include additional conversions
405 // src must be examined at runtime, to detect Byte, Character, etc.
406 fn = (strict
407 ? ValueConversions.unboxWiden(wdst)
408 : ValueConversions.unboxCast(wdst));
409 }
410 } else {
411 // Simple reference conversion.
412 // Note: Do not check for a class hierarchy relation
413 // between src and dst. In all cases a 'null' argument
414 // will pass the cast conversion.
415 return dst;
416 }
417 assert(fn.type().parameterCount() <= 1) : "pc"+Arrays.asList(src.getSimpleName(), dst.getSimpleName(), fn);
418 return fn;
419 }
420
421 static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
422 MethodType type = target.type();
423 int last = type.parameterCount() - 1;
424 if (type.parameterType(last) != arrayType)
425 target = target.asType(type.changeParameterType(last, arrayType));
426 target = target.asFixedArity(); // make sure this attribute is turned off
427 return new AsVarargsCollector(target, arrayType);
428 }
429
430 private static final class AsVarargsCollector extends DelegatingMethodHandle {
431 private final MethodHandle target;
432 private final Class<?> arrayType;
433 private @Stable MethodHandle asCollectorCache;
434
435 AsVarargsCollector(MethodHandle target, Class<?> arrayType) {
436 this(target.type(), target, arrayType);
437 }
438 AsVarargsCollector(MethodType type, MethodHandle target, Class<?> arrayType) {
439 super(type, target);
440 this.target = target;
441 this.arrayType = arrayType;
442 this.asCollectorCache = target.asCollector(arrayType, 0);
443 }
444
445 @Override
446 public boolean isVarargsCollector() {
447 return true;
448 }
449
450 @Override
451 protected MethodHandle getTarget() {
452 return target;
453 }
454
455 @Override
456 public MethodHandle asFixedArity() {
457 return target;
458 }
459
460 @Override
461 MethodHandle setVarargs(MemberName member) {
462 if (member.isVarargs()) return this;
463 return asFixedArity();
464 }
465
466 @Override
467 public MethodHandle asTypeUncached(MethodType newType) {
468 MethodType type = this.type();
469 int collectArg = type.parameterCount() - 1;
470 int newArity = newType.parameterCount();
471 if (newArity == collectArg+1 &&
472 type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
473 // if arity and trailing parameter are compatible, do normal thing
474 return asTypeCache = asFixedArity().asType(newType);
475 }
476 // check cache
477 MethodHandle acc = asCollectorCache;
478 if (acc != null && acc.type().parameterCount() == newArity)
479 return asTypeCache = acc.asType(newType);
480 // build and cache a collector
481 int arrayLength = newArity - collectArg;
482 MethodHandle collector;
483 try {
484 collector = asFixedArity().asCollector(arrayType, arrayLength);
485 assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
486 } catch (IllegalArgumentException ex) {
487 throw new WrongMethodTypeException("cannot build collector", ex);
488 }
489 asCollectorCache = collector;
490 return asTypeCache = collector.asType(newType);
491 }
492
493 @Override
494 boolean viewAsTypeChecks(MethodType newType, boolean strict) {
495 super.viewAsTypeChecks(newType, true);
496 if (strict) return true;
497 // extra assertion for non-strict checks:
498 assert (type().lastParameterType().getComponentType()
499 .isAssignableFrom(
500 newType.lastParameterType().getComponentType()))
501 : Arrays.asList(this, newType);
502 return true;
503 }
504 }
505
506 /** Factory method: Spread selected argument. */
507 static MethodHandle makeSpreadArguments(MethodHandle target,
508 Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
509 MethodType targetType = target.type();
510
511 for (int i = 0; i < spreadArgCount; i++) {
512 Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i);
513 if (arg == null) arg = Object.class;
514 targetType = targetType.changeParameterType(spreadArgPos + i, arg);
515 }
516 target = target.asType(targetType);
517
518 MethodType srcType = targetType
519 .replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType);
520 // Now build a LambdaForm.
521 MethodType lambdaType = srcType.invokerType();
522 Name[] names = arguments(spreadArgCount + 2, lambdaType);
523 int nameCursor = lambdaType.parameterCount();
524 int[] indexes = new int[targetType.parameterCount()];
525
526 for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) {
527 Class<?> src = lambdaType.parameterType(i);
528 if (i == spreadArgPos) {
529 // Spread the array.
530 MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType);
531 Name array = names[argIndex];
532 names[nameCursor++] = new Name(Lazy.NF_checkSpreadArgument, array, spreadArgCount);
533 for (int j = 0; j < spreadArgCount; i++, j++) {
534 indexes[i] = nameCursor;
535 names[nameCursor++] = new Name(aload, array, j);
536 }
537 } else if (i < indexes.length) {
538 indexes[i] = argIndex;
539 }
540 }
541 assert(nameCursor == names.length-1); // leave room for the final call
542
543 // Build argument array for the call.
544 Name[] targetArgs = new Name[targetType.parameterCount()];
545 for (int i = 0; i < targetType.parameterCount(); i++) {
546 int idx = indexes[i];
547 targetArgs[i] = names[idx];
548 }
549 names[names.length - 1] = new Name(target, (Object[]) targetArgs);
550
551 LambdaForm form = new LambdaForm("spread", lambdaType.parameterCount(), names);
552 return SimpleMethodHandle.make(srcType, form);
553 }
554
555 static void checkSpreadArgument(Object av, int n) {
556 if (av == null) {
557 if (n == 0) return;
558 } else if (av instanceof Object[]) {
559 int len = ((Object[])av).length;
560 if (len == n) return;
561 } else {
562 int len = java.lang.reflect.Array.getLength(av);
563 if (len == n) return;
564 }
565 // fall through to error:
566 throw newIllegalArgumentException("array is not of length "+n);
567 }
568
569 /**
570 * Pre-initialized NamedFunctions for bootstrapping purposes.
571 * Factored in an inner class to delay initialization until first usage.
572 */
573 static class Lazy {
574 private static final Class<?> MHI = MethodHandleImpl.class;
575 private static final Class<?> CLS = Class.class;
576
577 private static final MethodHandle[] ARRAYS;
578 private static final MethodHandle[] FILL_ARRAYS;
579
580 static final NamedFunction NF_checkSpreadArgument;
581 static final NamedFunction NF_guardWithCatch;
582 static final NamedFunction NF_throwException;
583 static final NamedFunction NF_profileBoolean;
584
585 static final MethodHandle MH_cast;
586 static final MethodHandle MH_selectAlternative;
587 static final MethodHandle MH_copyAsPrimitiveArray;
588 static final MethodHandle MH_fillNewTypedArray;
589 static final MethodHandle MH_fillNewArray;
590 static final MethodHandle MH_arrayIdentity;
591
592 static {
593 ARRAYS = makeArrays();
594 FILL_ARRAYS = makeFillArrays();
595
596 try {
597 NF_checkSpreadArgument = new NamedFunction(MHI.getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
598 NF_guardWithCatch = new NamedFunction(MHI.getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class,
599 MethodHandle.class, Object[].class));
600 NF_throwException = new NamedFunction(MHI.getDeclaredMethod("throwException", Throwable.class));
601 NF_profileBoolean = new NamedFunction(MHI.getDeclaredMethod("profileBoolean", boolean.class, int[].class));
602
603 NF_checkSpreadArgument.resolve();
604 NF_guardWithCatch.resolve();
605 NF_throwException.resolve();
606 NF_profileBoolean.resolve();
607
608 MH_cast = IMPL_LOOKUP.findVirtual(CLS, "cast",
609 MethodType.methodType(Object.class, Object.class));
610 MH_copyAsPrimitiveArray = IMPL_LOOKUP.findStatic(MHI, "copyAsPrimitiveArray",
611 MethodType.methodType(Object.class, Wrapper.class, Object[].class));
612 MH_arrayIdentity = IMPL_LOOKUP.findStatic(MHI, "identity",
613 MethodType.methodType(Object[].class, Object[].class));
614 MH_fillNewArray = IMPL_LOOKUP.findStatic(MHI, "fillNewArray",
615 MethodType.methodType(Object[].class, Integer.class, Object[].class));
616 MH_fillNewTypedArray = IMPL_LOOKUP.findStatic(MHI, "fillNewTypedArray",
617 MethodType.methodType(Object[].class, Object[].class, Integer.class, Object[].class));
618
619 MH_selectAlternative = makeIntrinsic(
620 IMPL_LOOKUP.findStatic(MHI, "selectAlternative",
621 MethodType.methodType(MethodHandle.class, boolean.class, MethodHandle.class, MethodHandle.class)),
622 Intrinsic.SELECT_ALTERNATIVE);
623 } catch (ReflectiveOperationException ex) {
624 throw newInternalError(ex);
625 }
626 }
627 }
628
629 /** Factory method: Collect or filter selected argument(s). */
630 static MethodHandle makeCollectArguments(MethodHandle target,
631 MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) {
632 MethodType targetType = target.type(); // (a..., c, [b...])=>r
633 MethodType collectorType = collector.type(); // (b...)=>c
634 int collectArgCount = collectorType.parameterCount();
635 Class<?> collectValType = collectorType.returnType();
636 int collectValCount = (collectValType == void.class ? 0 : 1);
637 MethodType srcType = targetType // (a..., [b...])=>r
638 .dropParameterTypes(collectArgPos, collectArgPos+collectValCount);
639 if (!retainOriginalArgs) { // (a..., b...)=>r
640 srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterList());
641 }
642 // in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ]
643 // out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ]
644 // out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ]
645
646 // Now build a LambdaForm.
647 MethodType lambdaType = srcType.invokerType();
648 Name[] names = arguments(2, lambdaType);
649 final int collectNamePos = names.length - 2;
650 final int targetNamePos = names.length - 1;
651
652 Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount);
653 names[collectNamePos] = new Name(collector, (Object[]) collectorArgs);
654
655 // Build argument array for the target.
656 // Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ].
657 // Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ].
658 Name[] targetArgs = new Name[targetType.parameterCount()];
659 int inputArgPos = 1; // incoming LF args to copy to target
660 int targetArgPos = 0; // fill pointer for targetArgs
661 int chunk = collectArgPos; // |headArgs|
662 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
663 inputArgPos += chunk;
664 targetArgPos += chunk;
665 if (collectValType != void.class) {
666 targetArgs[targetArgPos++] = names[collectNamePos];
667 }
668 chunk = collectArgCount;
669 if (retainOriginalArgs) {
670 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
671 targetArgPos += chunk; // optionally pass on the collected chunk
672 }
673 inputArgPos += chunk;
674 chunk = targetArgs.length - targetArgPos; // all the rest
675 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
676 assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also
677 names[targetNamePos] = new Name(target, (Object[]) targetArgs);
678
679 LambdaForm form = new LambdaForm("collect", lambdaType.parameterCount(), names);
680 return SimpleMethodHandle.make(srcType, form);
681 }
682
683 @LambdaForm.Hidden
684 static
685 MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
686 if (testResult) {
687 return target;
688 } else {
689 return fallback;
690 }
691 }
692
693 // Intrinsified by C2. Counters are used during parsing to calculate branch frequencies.
694 @LambdaForm.Hidden
695 @jdk.internal.HotSpotIntrinsicCandidate
696 static
697 boolean profileBoolean(boolean result, int[] counters) {
698 // Profile is int[2] where [0] and [1] correspond to false and true occurrences respectively.
699 int idx = result ? 1 : 0;
700 try {
701 counters[idx] = Math.addExact(counters[idx], 1);
702 } catch (ArithmeticException e) {
703 // Avoid continuous overflow by halving the problematic count.
704 counters[idx] = counters[idx] / 2;
705 }
706 return result;
707 }
708
709 // Intrinsified by C2. Returns true if obj is a compile-time constant.
710 @LambdaForm.Hidden
711 @jdk.internal.HotSpotIntrinsicCandidate
712 static
713 boolean isCompileConstant(Object obj) {
714 return false;
715 }
716
717 static
718 MethodHandle makeGuardWithTest(MethodHandle test,
719 MethodHandle target,
720 MethodHandle fallback) {
721 MethodType type = target.type();
722 assert(test.type().equals(type.changeReturnType(boolean.class)) && fallback.type().equals(type));
723 MethodType basicType = type.basicType();
724 LambdaForm form = makeGuardWithTestForm(basicType);
725 BoundMethodHandle mh;
726 try {
727 if (PROFILE_GWT) {
728 int[] counts = new int[2];
729 mh = (BoundMethodHandle)
730 BoundMethodHandle.speciesData_LLLL().constructor().invokeBasic(type, form,
731 (Object) test, (Object) profile(target), (Object) profile(fallback), counts);
732 } else {
733 mh = (BoundMethodHandle)
734 BoundMethodHandle.speciesData_LLL().constructor().invokeBasic(type, form,
735 (Object) test, (Object) profile(target), (Object) profile(fallback));
736 }
737 } catch (Throwable ex) {
738 throw uncaughtException(ex);
739 }
740 assert(mh.type() == type);
741 return mh;
742 }
743
744
745 static
746 MethodHandle profile(MethodHandle target) {
747 if (DONT_INLINE_THRESHOLD >= 0) {
748 return makeBlockInliningWrapper(target);
749 } else {
750 return target;
751 }
752 }
753
754 /**
755 * Block inlining during JIT-compilation of a target method handle if it hasn't been invoked enough times.
756 * Corresponding LambdaForm has @DontInline when compiled into bytecode.
757 */
758 static
759 MethodHandle makeBlockInliningWrapper(MethodHandle target) {
760 LambdaForm lform;
761 if (DONT_INLINE_THRESHOLD > 0) {
762 lform = PRODUCE_BLOCK_INLINING_FORM.apply(target);
763 } else {
764 lform = PRODUCE_REINVOKER_FORM.apply(target);
765 }
766 return new CountingWrapper(target, lform,
767 PRODUCE_BLOCK_INLINING_FORM, PRODUCE_REINVOKER_FORM,
768 DONT_INLINE_THRESHOLD);
769 }
770
771 /** Constructs reinvoker lambda form which block inlining during JIT-compilation for a particular method handle */
772 private static final Function<MethodHandle, LambdaForm> PRODUCE_BLOCK_INLINING_FORM = new Function<MethodHandle, LambdaForm>() {
773 @Override
774 public LambdaForm apply(MethodHandle target) {
775 return DelegatingMethodHandle.makeReinvokerForm(target,
776 MethodTypeForm.LF_DELEGATE_BLOCK_INLINING, CountingWrapper.class, "reinvoker.dontInline", false,
777 DelegatingMethodHandle.NF_getTarget, CountingWrapper.NF_maybeStopCounting);
778 }
779 };
780
781 /** Constructs simple reinvoker lambda form for a particular method handle */
782 private static final Function<MethodHandle, LambdaForm> PRODUCE_REINVOKER_FORM = new Function<MethodHandle, LambdaForm>() {
783 @Override
784 public LambdaForm apply(MethodHandle target) {
785 return DelegatingMethodHandle.makeReinvokerForm(target,
786 MethodTypeForm.LF_DELEGATE, DelegatingMethodHandle.class, DelegatingMethodHandle.NF_getTarget);
787 }
788 };
789
790 /**
791 * Counting method handle. It has 2 states: counting and non-counting.
792 * It is in counting state for the first n invocations and then transitions to non-counting state.
793 * Behavior in counting and non-counting states is determined by lambda forms produced by
794 * countingFormProducer & nonCountingFormProducer respectively.
795 */
796 static class CountingWrapper extends DelegatingMethodHandle {
797 private final MethodHandle target;
798 private int count;
799 private Function<MethodHandle, LambdaForm> countingFormProducer;
800 private Function<MethodHandle, LambdaForm> nonCountingFormProducer;
801 private volatile boolean isCounting;
802
803 private CountingWrapper(MethodHandle target, LambdaForm lform,
804 Function<MethodHandle, LambdaForm> countingFromProducer,
805 Function<MethodHandle, LambdaForm> nonCountingFormProducer,
806 int count) {
807 super(target.type(), lform);
808 this.target = target;
809 this.count = count;
810 this.countingFormProducer = countingFromProducer;
811 this.nonCountingFormProducer = nonCountingFormProducer;
812 this.isCounting = (count > 0);
813 }
814
815 @Hidden
816 @Override
817 protected MethodHandle getTarget() {
818 return target;
819 }
820
821 @Override
822 public MethodHandle asTypeUncached(MethodType newType) {
823 MethodHandle newTarget = target.asType(newType);
824 MethodHandle wrapper;
825 if (isCounting) {
826 LambdaForm lform;
827 lform = countingFormProducer.apply(newTarget);
828 wrapper = new CountingWrapper(newTarget, lform, countingFormProducer, nonCountingFormProducer, DONT_INLINE_THRESHOLD);
829 } else {
830 wrapper = newTarget; // no need for a counting wrapper anymore
831 }
832 return (asTypeCache = wrapper);
833 }
834
835 boolean countDown() {
836 int c = count;
837 if (c <= 1) {
838 // Try to limit number of updates. MethodHandle.updateForm() doesn't guarantee LF update visibility.
839 if (isCounting) {
840 isCounting = false;
841 return true;
842 } else {
843 return false;
844 }
845 } else {
846 count = c - 1;
847 return false;
848 }
849 }
850
851 @Hidden
852 static void maybeStopCounting(Object o1) {
853 CountingWrapper wrapper = (CountingWrapper) o1;
854 if (wrapper.countDown()) {
855 // Reached invocation threshold. Replace counting behavior with a non-counting one.
856 LambdaForm lform = wrapper.nonCountingFormProducer.apply(wrapper.target);
857 lform.compileToBytecode(); // speed up warmup by avoiding LF interpretation again after transition
858 wrapper.updateForm(lform);
859 }
860 }
861
862 static final NamedFunction NF_maybeStopCounting;
863 static {
864 Class<?> THIS_CLASS = CountingWrapper.class;
865 try {
866 NF_maybeStopCounting = new NamedFunction(THIS_CLASS.getDeclaredMethod("maybeStopCounting", Object.class));
867 } catch (ReflectiveOperationException ex) {
868 throw newInternalError(ex);
869 }
870 }
871 }
872
873 static
874 LambdaForm makeGuardWithTestForm(MethodType basicType) {
875 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWT);
876 if (lform != null) return lform;
877 final int THIS_MH = 0; // the BMH_LLL
878 final int ARG_BASE = 1; // start of incoming arguments
879 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
880 int nameCursor = ARG_LIMIT;
881 final int GET_TEST = nameCursor++;
882 final int GET_TARGET = nameCursor++;
883 final int GET_FALLBACK = nameCursor++;
884 final int GET_COUNTERS = PROFILE_GWT ? nameCursor++ : -1;
885 final int CALL_TEST = nameCursor++;
886 final int PROFILE = (GET_COUNTERS != -1) ? nameCursor++ : -1;
887 final int TEST = nameCursor-1; // previous statement: either PROFILE or CALL_TEST
888 final int SELECT_ALT = nameCursor++;
889 final int CALL_TARGET = nameCursor++;
890 assert(CALL_TARGET == SELECT_ALT+1); // must be true to trigger IBG.emitSelectAlternative
891
892 MethodType lambdaType = basicType.invokerType();
893 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
894
895 BoundMethodHandle.SpeciesData data =
896 (GET_COUNTERS != -1) ? BoundMethodHandle.speciesData_LLLL()
897 : BoundMethodHandle.speciesData_LLL();
898 names[THIS_MH] = names[THIS_MH].withConstraint(data);
899 names[GET_TEST] = new Name(data.getterFunction(0), names[THIS_MH]);
900 names[GET_TARGET] = new Name(data.getterFunction(1), names[THIS_MH]);
901 names[GET_FALLBACK] = new Name(data.getterFunction(2), names[THIS_MH]);
902 if (GET_COUNTERS != -1) {
903 names[GET_COUNTERS] = new Name(data.getterFunction(3), names[THIS_MH]);
904 }
905 Object[] invokeArgs = Arrays.copyOfRange(names, 0, ARG_LIMIT, Object[].class);
906
907 // call test
908 MethodType testType = basicType.changeReturnType(boolean.class).basicType();
909 invokeArgs[0] = names[GET_TEST];
910 names[CALL_TEST] = new Name(testType, invokeArgs);
911
912 // profile branch
913 if (PROFILE != -1) {
914 names[PROFILE] = new Name(Lazy.NF_profileBoolean, names[CALL_TEST], names[GET_COUNTERS]);
915 }
916 // call selectAlternative
917 names[SELECT_ALT] = new Name(Lazy.MH_selectAlternative, names[TEST], names[GET_TARGET], names[GET_FALLBACK]);
918
919 // call target or fallback
920 invokeArgs[0] = names[SELECT_ALT];
921 names[CALL_TARGET] = new Name(basicType, invokeArgs);
922
923 lform = new LambdaForm("guard", lambdaType.parameterCount(), names, /*forceInline=*/true);
924
925 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWT, lform);
926 }
927
928 /**
929 * The LambdaForm shape for catchException combinator is the following:
930 * <blockquote><pre>{@code
931 * guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{
932 * t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L);
933 * t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L);
934 * t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L);
935 * t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L);
936 * t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L);
937 * t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L);
938 * t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L);
939 * t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I}
940 * }</pre></blockquote>
941 *
942 * argL0 and argL2 are target and catcher method handles. argL1 is exception class.
943 * argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[]
944 * (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()).
945 *
946 * Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms
947 * among catchException combinators with the same basic type.
948 */
949 private static LambdaForm makeGuardWithCatchForm(MethodType basicType) {
950 MethodType lambdaType = basicType.invokerType();
951
952 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC);
953 if (lform != null) {
954 return lform;
955 }
956 final int THIS_MH = 0; // the BMH_LLLLL
957 final int ARG_BASE = 1; // start of incoming arguments
958 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
959
960 int nameCursor = ARG_LIMIT;
961 final int GET_TARGET = nameCursor++;
962 final int GET_CLASS = nameCursor++;
963 final int GET_CATCHER = nameCursor++;
964 final int GET_COLLECT_ARGS = nameCursor++;
965 final int GET_UNBOX_RESULT = nameCursor++;
966 final int BOXED_ARGS = nameCursor++;
967 final int TRY_CATCH = nameCursor++;
968 final int UNBOX_RESULT = nameCursor++;
969
970 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
971
972 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
973 names[THIS_MH] = names[THIS_MH].withConstraint(data);
974 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
975 names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]);
976 names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]);
977 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]);
978 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]);
979
980 // FIXME: rework argument boxing/result unboxing logic for LF interpretation
981
982 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
983 MethodType collectArgsType = basicType.changeReturnType(Object.class);
984 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
985 Object[] args = new Object[invokeBasic.type().parameterCount()];
986 args[0] = names[GET_COLLECT_ARGS];
987 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
988 names[BOXED_ARGS] = new Name(makeIntrinsic(invokeBasic, Intrinsic.GUARD_WITH_CATCH), args);
989
990 // t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L);
991 Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]};
992 names[TRY_CATCH] = new Name(Lazy.NF_guardWithCatch, gwcArgs);
993
994 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
995 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
996 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]};
997 names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
998
999 lform = new LambdaForm("guardWithCatch", lambdaType.parameterCount(), names);
1000
1001 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform);
1002 }
1003
1004 static
1005 MethodHandle makeGuardWithCatch(MethodHandle target,
1006 Class<? extends Throwable> exType,
1007 MethodHandle catcher) {
1008 MethodType type = target.type();
1009 LambdaForm form = makeGuardWithCatchForm(type.basicType());
1010
1011 // Prepare auxiliary method handles used during LambdaForm interpretation.
1012 // Box arguments and wrap them into Object[]: ValueConversions.array().
1013 MethodType varargsType = type.changeReturnType(Object[].class);
1014 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
1015 // Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore().
1016 MethodHandle unboxResult;
1017 Class<?> rtype = type.returnType();
1018 if (rtype.isPrimitive()) {
1019 if (rtype == void.class) {
1020 unboxResult = ValueConversions.ignore();
1021 } else {
1022 Wrapper w = Wrapper.forPrimitiveType(type.returnType());
1023 unboxResult = ValueConversions.unboxExact(w);
1024 }
1025 } else {
1026 unboxResult = MethodHandles.identity(Object.class);
1027 }
1028
1029 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
1030 BoundMethodHandle mh;
1031 try {
1032 mh = (BoundMethodHandle)
1033 data.constructor().invokeBasic(type, form, (Object) target, (Object) exType, (Object) catcher,
1034 (Object) collectArgs, (Object) unboxResult);
1035 } catch (Throwable ex) {
1036 throw uncaughtException(ex);
1037 }
1038 assert(mh.type() == type);
1039 return mh;
1040 }
1041
1042 /**
1043 * Intrinsified during LambdaForm compilation
1044 * (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}).
1045 */
1046 @LambdaForm.Hidden
1047 static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher,
1048 Object... av) throws Throwable {
1049 // Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case.
1050 try {
1051 return target.asFixedArity().invokeWithArguments(av);
1052 } catch (Throwable t) {
1053 if (!exType.isInstance(t)) throw t;
1054 return catcher.asFixedArity().invokeWithArguments(prepend(t, av));
1055 }
1056 }
1057
1058 /** Prepend an element {@code elem} to an {@code array}. */
1059 @LambdaForm.Hidden
1060 private static Object[] prepend(Object elem, Object[] array) {
1061 Object[] newArray = new Object[array.length+1];
1062 newArray[0] = elem;
1063 System.arraycopy(array, 0, newArray, 1, array.length);
1064 return newArray;
1065 }
1066
1067 static
1068 MethodHandle throwException(MethodType type) {
1069 assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
1070 int arity = type.parameterCount();
1071 if (arity > 1) {
1072 MethodHandle mh = throwException(type.dropParameterTypes(1, arity));
1073 mh = MethodHandles.dropArguments(mh, 1, type.parameterList().subList(1, arity));
1074 return mh;
1075 }
1076 return makePairwiseConvert(Lazy.NF_throwException.resolvedHandle(), type, false, true);
1077 }
1078
1079 static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
1080
1081 static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
1082 static MethodHandle fakeMethodHandleInvoke(MemberName method) {
1083 int idx;
1084 assert(method.isMethodHandleInvoke());
1085 switch (method.getName()) {
1086 case "invoke": idx = 0; break;
1087 case "invokeExact": idx = 1; break;
1088 default: throw new InternalError(method.getName());
1089 }
1090 MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
1091 if (mh != null) return mh;
1092 MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
1093 MethodHandle.class, Object[].class);
1094 mh = throwException(type);
1095 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
1096 if (!method.getInvocationType().equals(mh.type()))
1097 throw new InternalError(method.toString());
1098 mh = mh.withInternalMemberName(method, false);
1099 mh = mh.asVarargsCollector(Object[].class);
1100 assert(method.isVarargs());
1101 FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
1102 return mh;
1103 }
1104
1105 /**
1106 * Create an alias for the method handle which, when called,
1107 * appears to be called from the same class loader and protection domain
1108 * as hostClass.
1109 * This is an expensive no-op unless the method which is called
1110 * is sensitive to its caller. A small number of system methods
1111 * are in this category, including Class.forName and Method.invoke.
1112 */
1113 static
1114 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1115 return BindCaller.bindCaller(mh, hostClass);
1116 }
1117
1118 // Put the whole mess into its own nested class.
1119 // That way we can lazily load the code and set up the constants.
1120 private static class BindCaller {
1121 static
1122 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1123 // Do not use this function to inject calls into system classes.
1124 if (hostClass == null
1125 || (hostClass.isArray() ||
1126 hostClass.isPrimitive() ||
1127 hostClass.getName().startsWith("java.") ||
1128 hostClass.getName().startsWith("sun."))) {
1129 throw new InternalError(); // does not happen, and should not anyway
1130 }
1131 // For simplicity, convert mh to a varargs-like method.
1132 MethodHandle vamh = prepareForInvoker(mh);
1133 // Cache the result of makeInjectedInvoker once per argument class.
1134 MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
1135 return restoreToType(bccInvoker.bindTo(vamh), mh, hostClass);
1136 }
1137
1138 private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
1139 Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null);
1140 if (hostClass.getClassLoader() != bcc.getClassLoader())
1141 throw new InternalError(hostClass.getName()+" (CL)");
1142 try {
1143 if (hostClass.getProtectionDomain() != bcc.getProtectionDomain())
1144 throw new InternalError(hostClass.getName()+" (PD)");
1145 } catch (SecurityException ex) {
1146 // Self-check was blocked by security manager. This is OK.
1147 // In fact the whole try body could be turned into an assertion.
1148 }
1149 try {
1150 MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class));
1151 init.invokeExact(); // force initialization of the class
1152 } catch (Throwable ex) {
1153 throw uncaughtException(ex);
1154 }
1155 MethodHandle bccInvoker;
1156 try {
1157 MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1158 bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT);
1159 } catch (ReflectiveOperationException ex) {
1160 throw uncaughtException(ex);
1161 }
1162 // Test the invoker, to ensure that it really injects into the right place.
1163 try {
1164 MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
1165 Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc});
1166 } catch (Throwable ex) {
1167 throw new InternalError(ex);
1168 }
1169 return bccInvoker;
1170 }
1171 private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() {
1172 @Override protected MethodHandle computeValue(Class<?> hostClass) {
1173 return makeInjectedInvoker(hostClass);
1174 }
1175 };
1176
1177 // Adapt mh so that it can be called directly from an injected invoker:
1178 private static MethodHandle prepareForInvoker(MethodHandle mh) {
1179 mh = mh.asFixedArity();
1180 MethodType mt = mh.type();
1181 int arity = mt.parameterCount();
1182 MethodHandle vamh = mh.asType(mt.generic());
1183 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1184 vamh = vamh.asSpreader(Object[].class, arity);
1185 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1186 return vamh;
1187 }
1188
1189 // Undo the adapter effect of prepareForInvoker:
1190 private static MethodHandle restoreToType(MethodHandle vamh,
1191 MethodHandle original,
1192 Class<?> hostClass) {
1193 MethodType type = original.type();
1194 MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount());
1195 MemberName member = original.internalMemberName();
1196 mh = mh.asType(type);
1197 mh = new WrappedMember(mh, type, member, original.isInvokeSpecial(), hostClass);
1198 return mh;
1199 }
1200
1201 private static final MethodHandle MH_checkCallerClass;
1202 static {
1203 final Class<?> THIS_CLASS = BindCaller.class;
1204 assert(checkCallerClass(THIS_CLASS, THIS_CLASS));
1205 try {
1206 MH_checkCallerClass = IMPL_LOOKUP
1207 .findStatic(THIS_CLASS, "checkCallerClass",
1208 MethodType.methodType(boolean.class, Class.class, Class.class));
1209 assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS, THIS_CLASS));
1210 } catch (Throwable ex) {
1211 throw new InternalError(ex);
1212 }
1213 }
1214
1215 @CallerSensitive
1216 private static boolean checkCallerClass(Class<?> expected, Class<?> expected2) {
1217 // This method is called via MH_checkCallerClass and so it's
1218 // correct to ask for the immediate caller here.
1219 Class<?> actual = Reflection.getCallerClass();
1220 if (actual != expected && actual != expected2)
1221 throw new InternalError("found "+actual.getName()+", expected "+expected.getName()
1222 +(expected == expected2 ? "" : ", or else "+expected2.getName()));
1223 return true;
1224 }
1225
1226 private static final byte[] T_BYTES;
1227 static {
1228 final Object[] values = {null};
1229 AccessController.doPrivileged(new PrivilegedAction<>() {
1230 public Void run() {
1231 try {
1232 Class<T> tClass = T.class;
1233 String tName = tClass.getName();
1234 String tResource = tName.substring(tName.lastIndexOf('.')+1)+".class";
1235 java.net.URLConnection uconn = tClass.getResource(tResource).openConnection();
1236 int len = uconn.getContentLength();
1237 byte[] bytes = new byte[len];
1238 try (java.io.InputStream str = uconn.getInputStream()) {
1239 int nr = str.read(bytes);
1240 if (nr != len) throw new java.io.IOException(tResource);
1241 }
1242 values[0] = bytes;
1243 } catch (java.io.IOException ex) {
1244 throw new InternalError(ex);
1245 }
1246 return null;
1247 }
1248 });
1249 T_BYTES = (byte[]) values[0];
1250 }
1251
1252 // The following class is used as a template for Unsafe.defineAnonymousClass:
1253 private static class T {
1254 static void init() { } // side effect: initializes this class
1255 static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
1256 return vamh.invokeExact(args);
1257 }
1258 }
1259 }
1260
1261
1262 /** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */
1263 private static final class WrappedMember extends DelegatingMethodHandle {
1264 private final MethodHandle target;
1265 private final MemberName member;
1266 private final Class<?> callerClass;
1267 private final boolean isInvokeSpecial;
1268
1269 private WrappedMember(MethodHandle target, MethodType type,
1270 MemberName member, boolean isInvokeSpecial,
1271 Class<?> callerClass) {
1272 super(type, target);
1273 this.target = target;
1274 this.member = member;
1275 this.callerClass = callerClass;
1276 this.isInvokeSpecial = isInvokeSpecial;
1277 }
1278
1279 @Override
1280 MemberName internalMemberName() {
1281 return member;
1282 }
1283 @Override
1284 Class<?> internalCallerClass() {
1285 return callerClass;
1286 }
1287 @Override
1288 boolean isInvokeSpecial() {
1289 return isInvokeSpecial;
1290 }
1291 @Override
1292 protected MethodHandle getTarget() {
1293 return target;
1294 }
1295 @Override
1296 public MethodHandle asTypeUncached(MethodType newType) {
1297 // This MH is an alias for target, except for the MemberName
1298 // Drop the MemberName if there is any conversion.
1299 return asTypeCache = target.asType(newType);
1300 }
1301 }
1302
1303 static MethodHandle makeWrappedMember(MethodHandle target, MemberName member, boolean isInvokeSpecial) {
1304 if (member.equals(target.internalMemberName()) && isInvokeSpecial == target.isInvokeSpecial())
1305 return target;
1306 return new WrappedMember(target, target.type(), member, isInvokeSpecial, null);
1307 }
1308
1309 /** Intrinsic IDs */
1310 /*non-public*/
1311 enum Intrinsic {
1312 SELECT_ALTERNATIVE,
1313 GUARD_WITH_CATCH,
1314 NEW_ARRAY,
1315 ARRAY_LOAD,
1316 ARRAY_STORE,
1317 IDENTITY,
1318 ZERO,
1319 NONE // no intrinsic associated
1320 }
1321
1322 /** Mark arbitrary method handle as intrinsic.
1323 * InvokerBytecodeGenerator uses this info to produce more efficient bytecode shape. */
1324 private static final class IntrinsicMethodHandle extends DelegatingMethodHandle {
1325 private final MethodHandle target;
1326 private final Intrinsic intrinsicName;
1327
1328 IntrinsicMethodHandle(MethodHandle target, Intrinsic intrinsicName) {
1329 super(target.type(), target);
1330 this.target = target;
1331 this.intrinsicName = intrinsicName;
1332 }
1333
1334 @Override
1335 protected MethodHandle getTarget() {
1336 return target;
1337 }
1338
1339 @Override
1340 Intrinsic intrinsicName() {
1341 return intrinsicName;
1342 }
1343
1344 @Override
1345 public MethodHandle asTypeUncached(MethodType newType) {
1346 // This MH is an alias for target, except for the intrinsic name
1347 // Drop the name if there is any conversion.
1348 return asTypeCache = target.asType(newType);
1349 }
1350
1351 @Override
1352 String internalProperties() {
1353 return super.internalProperties() +
1354 "\n& Intrinsic="+intrinsicName;
1355 }
1356
1357 @Override
1358 public MethodHandle asCollector(Class<?> arrayType, int arrayLength) {
1359 if (intrinsicName == Intrinsic.IDENTITY) {
1360 MethodType resultType = type().asCollectorType(arrayType, arrayLength);
1361 MethodHandle newArray = MethodHandleImpl.varargsArray(arrayType, arrayLength);
1362 return newArray.asType(resultType);
1363 }
1364 return super.asCollector(arrayType, arrayLength);
1365 }
1366 }
1367
1368 static MethodHandle makeIntrinsic(MethodHandle target, Intrinsic intrinsicName) {
1369 if (intrinsicName == target.intrinsicName())
1370 return target;
1371 return new IntrinsicMethodHandle(target, intrinsicName);
1372 }
1373
1374 static MethodHandle makeIntrinsic(MethodType type, LambdaForm form, Intrinsic intrinsicName) {
1375 return new IntrinsicMethodHandle(SimpleMethodHandle.make(type, form), intrinsicName);
1376 }
1377
1378 /// Collection of multiple arguments.
1379
1380 private static MethodHandle findCollector(String name, int nargs, Class<?> rtype, Class<?>... ptypes) {
1381 MethodType type = MethodType.genericMethodType(nargs)
1382 .changeReturnType(rtype)
1383 .insertParameterTypes(0, ptypes);
1384 try {
1385 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, name, type);
1386 } catch (ReflectiveOperationException ex) {
1387 return null;
1388 }
1389 }
1390
1391 private static final Object[] NO_ARGS_ARRAY = {};
1392 private static Object[] makeArray(Object... args) { return args; }
1393 private static Object[] array() { return NO_ARGS_ARRAY; }
1394 private static Object[] array(Object a0)
1395 { return makeArray(a0); }
1396 private static Object[] array(Object a0, Object a1)
1397 { return makeArray(a0, a1); }
1398 private static Object[] array(Object a0, Object a1, Object a2)
1399 { return makeArray(a0, a1, a2); }
1400 private static Object[] array(Object a0, Object a1, Object a2, Object a3)
1401 { return makeArray(a0, a1, a2, a3); }
1402 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1403 Object a4)
1404 { return makeArray(a0, a1, a2, a3, a4); }
1405 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1406 Object a4, Object a5)
1407 { return makeArray(a0, a1, a2, a3, a4, a5); }
1408 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1409 Object a4, Object a5, Object a6)
1410 { return makeArray(a0, a1, a2, a3, a4, a5, a6); }
1411 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1412 Object a4, Object a5, Object a6, Object a7)
1413 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7); }
1414 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1415 Object a4, Object a5, Object a6, Object a7,
1416 Object a8)
1417 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8); }
1418 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1419 Object a4, Object a5, Object a6, Object a7,
1420 Object a8, Object a9)
1421 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
1422
1423 private static final int ARRAYS_COUNT = 11;
1424
1425 private static MethodHandle[] makeArrays() {
1426 MethodHandle[] mhs = new MethodHandle[MAX_ARITY + 1];
1427 for (int i = 0; i < ARRAYS_COUNT; i++) {
1428 MethodHandle mh = findCollector("array", i, Object[].class);
1429 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1430 mhs[i] = mh;
1431 }
1432 assert(assertArrayMethodCount(mhs));
1433 return mhs;
1434 }
1435
1436 private static boolean assertArrayMethodCount(MethodHandle[] mhs) {
1437 assert(findCollector("array", ARRAYS_COUNT, Object[].class) == null);
1438 for (int i = 0; i < ARRAYS_COUNT; i++) {
1439 assert(mhs[i] != null);
1440 }
1441 return true;
1442 }
1443
1444 // filling versions of the above:
1445 // using Integer len instead of int len and no varargs to avoid bootstrapping problems
1446 private static Object[] fillNewArray(Integer len, Object[] /*not ...*/ args) {
1447 Object[] a = new Object[len];
1448 fillWithArguments(a, 0, args);
1449 return a;
1450 }
1451 private static Object[] fillNewTypedArray(Object[] example, Integer len, Object[] /*not ...*/ args) {
1452 Object[] a = Arrays.copyOf(example, len);
1453 assert(a.getClass() != Object[].class);
1454 fillWithArguments(a, 0, args);
1455 return a;
1456 }
1457 private static void fillWithArguments(Object[] a, int pos, Object... args) {
1458 System.arraycopy(args, 0, a, pos, args.length);
1459 }
1460 // using Integer pos instead of int pos to avoid bootstrapping problems
1461 private static Object[] fillArray(Integer pos, Object[] a, Object a0)
1462 { fillWithArguments(a, pos, a0); return a; }
1463 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1)
1464 { fillWithArguments(a, pos, a0, a1); return a; }
1465 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2)
1466 { fillWithArguments(a, pos, a0, a1, a2); return a; }
1467 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3)
1468 { fillWithArguments(a, pos, a0, a1, a2, a3); return a; }
1469 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1470 Object a4)
1471 { fillWithArguments(a, pos, a0, a1, a2, a3, a4); return a; }
1472 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1473 Object a4, Object a5)
1474 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5); return a; }
1475 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1476 Object a4, Object a5, Object a6)
1477 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6); return a; }
1478 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1479 Object a4, Object a5, Object a6, Object a7)
1480 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7); return a; }
1481 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1482 Object a4, Object a5, Object a6, Object a7,
1483 Object a8)
1484 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8); return a; }
1485 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1486 Object a4, Object a5, Object a6, Object a7,
1487 Object a8, Object a9)
1488 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); return a; }
1489
1490 private static final int FILL_ARRAYS_COUNT = 11; // current number of fillArray methods
1491
1492 private static MethodHandle[] makeFillArrays() {
1493 MethodHandle[] mhs = new MethodHandle[FILL_ARRAYS_COUNT];
1494 mhs[0] = null; // there is no empty fill; at least a0 is required
1495 for (int i = 1; i < FILL_ARRAYS_COUNT; i++) {
1496 MethodHandle mh = findCollector("fillArray", i, Object[].class, Integer.class, Object[].class);
1497 mhs[i] = mh;
1498 }
1499 assert(assertFillArrayMethodCount(mhs));
1500 return mhs;
1501 }
1502
1503 private static boolean assertFillArrayMethodCount(MethodHandle[] mhs) {
1504 assert(findCollector("fillArray", FILL_ARRAYS_COUNT, Object[].class, Integer.class, Object[].class) == null);
1505 for (int i = 1; i < FILL_ARRAYS_COUNT; i++) {
1506 assert(mhs[i] != null);
1507 }
1508 return true;
1509 }
1510
1511 private static Object copyAsPrimitiveArray(Wrapper w, Object... boxes) {
1512 Object a = w.makeArray(boxes.length);
1513 w.copyArrayUnboxing(boxes, 0, a, 0, boxes.length);
1514 return a;
1515 }
1516
1517 /** Return a method handle that takes the indicated number of Object
1518 * arguments and returns an Object array of them, as if for varargs.
1519 */
1520 static MethodHandle varargsArray(int nargs) {
1521 MethodHandle mh = Lazy.ARRAYS[nargs];
1522 if (mh != null) return mh;
1523 mh = buildVarargsArray(Lazy.MH_fillNewArray, Lazy.MH_arrayIdentity, nargs);
1524 assert(assertCorrectArity(mh, nargs));
1525 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1526 return Lazy.ARRAYS[nargs] = mh;
1527 }
1528
1529 private static boolean assertCorrectArity(MethodHandle mh, int arity) {
1530 assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh;
1531 return true;
1532 }
1533
1534 // Array identity function (used as Lazy.MH_arrayIdentity).
1535 static <T> T[] identity(T[] x) {
1536 return x;
1537 }
1538
1539 private static MethodHandle buildVarargsArray(MethodHandle newArray, MethodHandle finisher, int nargs) {
1540 // Build up the result mh as a sequence of fills like this:
1541 // finisher(fill(fill(newArrayWA(23,x1..x10),10,x11..x20),20,x21..x23))
1542 // The various fill(_,10*I,___*[J]) are reusable.
1543 int leftLen = Math.min(nargs, LEFT_ARGS); // absorb some arguments immediately
1544 int rightLen = nargs - leftLen;
1545 MethodHandle leftCollector = newArray.bindTo(nargs);
1546 leftCollector = leftCollector.asCollector(Object[].class, leftLen);
1547 MethodHandle mh = finisher;
1548 if (rightLen > 0) {
1549 MethodHandle rightFiller = fillToRight(LEFT_ARGS + rightLen);
1550 if (mh == Lazy.MH_arrayIdentity)
1551 mh = rightFiller;
1552 else
1553 mh = MethodHandles.collectArguments(mh, 0, rightFiller);
1554 }
1555 if (mh == Lazy.MH_arrayIdentity)
1556 mh = leftCollector;
1557 else
1558 mh = MethodHandles.collectArguments(mh, 0, leftCollector);
1559 return mh;
1560 }
1561
1562 private static final int LEFT_ARGS = FILL_ARRAYS_COUNT - 1;
1563 private static final MethodHandle[] FILL_ARRAY_TO_RIGHT = new MethodHandle[MAX_ARITY+1];
1564 /** fill_array_to_right(N).invoke(a, argL..arg[N-1])
1565 * fills a[L]..a[N-1] with corresponding arguments,
1566 * and then returns a. The value L is a global constant (LEFT_ARGS).
1567 */
1568 private static MethodHandle fillToRight(int nargs) {
1569 MethodHandle filler = FILL_ARRAY_TO_RIGHT[nargs];
1570 if (filler != null) return filler;
1571 filler = buildFiller(nargs);
1572 assert(assertCorrectArity(filler, nargs - LEFT_ARGS + 1));
1573 return FILL_ARRAY_TO_RIGHT[nargs] = filler;
1574 }
1575 private static MethodHandle buildFiller(int nargs) {
1576 if (nargs <= LEFT_ARGS)
1577 return Lazy.MH_arrayIdentity; // no args to fill; return the array unchanged
1578 // we need room for both mh and a in mh.invoke(a, arg*[nargs])
1579 final int CHUNK = LEFT_ARGS;
1580 int rightLen = nargs % CHUNK;
1581 int midLen = nargs - rightLen;
1582 if (rightLen == 0) {
1583 midLen = nargs - (rightLen = CHUNK);
1584 if (FILL_ARRAY_TO_RIGHT[midLen] == null) {
1585 // build some precursors from left to right
1586 for (int j = LEFT_ARGS % CHUNK; j < midLen; j += CHUNK)
1587 if (j > LEFT_ARGS) fillToRight(j);
1588 }
1589 }
1590 if (midLen < LEFT_ARGS) rightLen = nargs - (midLen = LEFT_ARGS);
1591 assert(rightLen > 0);
1592 MethodHandle midFill = fillToRight(midLen); // recursive fill
1593 MethodHandle rightFill = Lazy.FILL_ARRAYS[rightLen].bindTo(midLen); // [midLen..nargs-1]
1594 assert(midFill.type().parameterCount() == 1 + midLen - LEFT_ARGS);
1595 assert(rightFill.type().parameterCount() == 1 + rightLen);
1596
1597 // Combine the two fills:
1598 // right(mid(a, x10..x19), x20..x23)
1599 // The final product will look like this:
1600 // right(mid(newArrayLeft(24, x0..x9), x10..x19), x20..x23)
1601 if (midLen == LEFT_ARGS)
1602 return rightFill;
1603 else
1604 return MethodHandles.collectArguments(rightFill, 0, midFill);
1605 }
1606
1607 // Type-polymorphic version of varargs maker.
1608 private static final ClassValue<MethodHandle[]> TYPED_COLLECTORS
1609 = new ClassValue<MethodHandle[]>() {
1610 @Override
1611 protected MethodHandle[] computeValue(Class<?> type) {
1612 return new MethodHandle[256];
1613 }
1614 };
1615
1616 static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM
1617
1618 /** Return a method handle that takes the indicated number of
1619 * typed arguments and returns an array of them.
1620 * The type argument is the array type.
1621 */
1622 static MethodHandle varargsArray(Class<?> arrayType, int nargs) {
1623 Class<?> elemType = arrayType.getComponentType();
1624 if (elemType == null) throw new IllegalArgumentException("not an array: "+arrayType);
1625 // FIXME: Need more special casing and caching here.
1626 if (nargs >= MAX_JVM_ARITY/2 - 1) {
1627 int slots = nargs;
1628 final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH
1629 if (slots <= MAX_ARRAY_SLOTS && elemType.isPrimitive())
1630 slots *= Wrapper.forPrimitiveType(elemType).stackSlots();
1631 if (slots > MAX_ARRAY_SLOTS)
1632 throw new IllegalArgumentException("too many arguments: "+arrayType.getSimpleName()+", length "+nargs);
1633 }
1634 if (elemType == Object.class)
1635 return varargsArray(nargs);
1636 // other cases: primitive arrays, subtypes of Object[]
1637 MethodHandle cache[] = TYPED_COLLECTORS.get(elemType);
1638 MethodHandle mh = nargs < cache.length ? cache[nargs] : null;
1639 if (mh != null) return mh;
1640 if (nargs == 0) {
1641 Object example = java.lang.reflect.Array.newInstance(arrayType.getComponentType(), 0);
1642 mh = MethodHandles.constant(arrayType, example);
1643 } else if (elemType.isPrimitive()) {
1644 MethodHandle builder = Lazy.MH_fillNewArray;
1645 MethodHandle producer = buildArrayProducer(arrayType);
1646 mh = buildVarargsArray(builder, producer, nargs);
1647 } else {
1648 Class<? extends Object[]> objArrayType = arrayType.asSubclass(Object[].class);
1649 Object[] example = Arrays.copyOf(NO_ARGS_ARRAY, 0, objArrayType);
1650 MethodHandle builder = Lazy.MH_fillNewTypedArray.bindTo(example);
1651 MethodHandle producer = Lazy.MH_arrayIdentity; // must be weakly typed
1652 mh = buildVarargsArray(builder, producer, nargs);
1653 }
1654 mh = mh.asType(MethodType.methodType(arrayType, Collections.<Class<?>>nCopies(nargs, elemType)));
1655 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1656 assert(assertCorrectArity(mh, nargs));
1657 if (nargs < cache.length)
1658 cache[nargs] = mh;
1659 return mh;
1660 }
1661
1662 private static MethodHandle buildArrayProducer(Class<?> arrayType) {
1663 Class<?> elemType = arrayType.getComponentType();
1664 assert(elemType.isPrimitive());
1665 return Lazy.MH_copyAsPrimitiveArray.bindTo(Wrapper.forPrimitiveType(elemType));
1666 }
1667
1668 /*non-public*/ static void assertSame(Object mh1, Object mh2) {
1669 if (mh1 != mh2) {
1670 String msg = String.format("mh1 != mh2: mh1 = %s (form: %s); mh2 = %s (form: %s)",
1671 mh1, ((MethodHandle)mh1).form,
1672 mh2, ((MethodHandle)mh2).form);
1673 throw newInternalError(msg);
1674 }
1675 }
1676 }