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.Arrays;
31 import java.util.Collections;
32 import java.util.Iterator;
33 import java.util.List;
34 import java.util.function.Function;
35 import java.util.stream.Collectors;
36
37 import sun.invoke.empty.Empty;
38 import sun.invoke.util.ValueConversions;
39 import sun.invoke.util.VerifyType;
40 import sun.invoke.util.Wrapper;
41 import sun.reflect.CallerSensitive;
42 import sun.reflect.Reflection;
43 import static java.lang.invoke.LambdaForm.*;
44 import static java.lang.invoke.MethodHandleStatics.*;
45 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
46
47 /**
48 * Trusted implementation code for MethodHandle.
49 * @author jrose
50 */
51 /*non-public*/ abstract class MethodHandleImpl {
52 // Do not adjust this except for special platforms:
53 private static final int MAX_ARITY;
54 static {
55 final Object[] values = { 255 };
56 AccessController.doPrivileged(new PrivilegedAction<>() {
57 @Override
58 public Void run() {
59 values[0] = Integer.getInteger(MethodHandleImpl.class.getName()+".MAX_ARITY", 255);
60 return null;
61 }
62 });
63 MAX_ARITY = (Integer) values[0];
64 }
65
66 /// Factory methods to create method handles:
67
68 static void initStatics() {
69 // Trigger selected static initializations.
70 MemberName.Factory.INSTANCE.getClass();
71 }
72
73 static MethodHandle makeArrayElementAccessor(Class<?> arrayClass, boolean isSetter) {
74 if (arrayClass == Object[].class)
75 return (isSetter ? ArrayAccessor.OBJECT_ARRAY_SETTER : ArrayAccessor.OBJECT_ARRAY_GETTER);
76 if (!arrayClass.isArray())
77 throw newIllegalArgumentException("not an array: "+arrayClass);
78 MethodHandle[] cache = ArrayAccessor.TYPED_ACCESSORS.get(arrayClass);
79 int cacheIndex = (isSetter ? ArrayAccessor.SETTER_INDEX : ArrayAccessor.GETTER_INDEX);
80 MethodHandle mh = cache[cacheIndex];
81 if (mh != null) return mh;
82 mh = ArrayAccessor.getAccessor(arrayClass, isSetter);
83 MethodType correctType = ArrayAccessor.correctType(arrayClass, isSetter);
84 if (mh.type() != correctType) {
85 assert(mh.type().parameterType(0) == Object[].class);
86 assert((isSetter ? mh.type().parameterType(2) : mh.type().returnType()) == Object.class);
87 assert(isSetter || correctType.parameterType(0).getComponentType() == correctType.returnType());
88 // safe to view non-strictly, because element type follows from array type
89 mh = mh.viewAsType(correctType, false);
90 }
91 mh = makeIntrinsic(mh, (isSetter ? Intrinsic.ARRAY_STORE : Intrinsic.ARRAY_LOAD));
92 // Atomically update accessor cache.
93 synchronized(cache) {
94 if (cache[cacheIndex] == null) {
95 cache[cacheIndex] = mh;
96 } else {
97 // Throw away newly constructed accessor and use cached version.
98 mh = cache[cacheIndex];
99 }
100 }
101 return mh;
102 }
103
104 static final class ArrayAccessor {
105 /// Support for array element access
106 static final int GETTER_INDEX = 0, SETTER_INDEX = 1, INDEX_LIMIT = 2;
107 static final ClassValue<MethodHandle[]> TYPED_ACCESSORS
108 = new ClassValue<MethodHandle[]>() {
109 @Override
110 protected MethodHandle[] computeValue(Class<?> type) {
111 return new MethodHandle[INDEX_LIMIT];
112 }
113 };
114 static final MethodHandle OBJECT_ARRAY_GETTER, OBJECT_ARRAY_SETTER;
115 static {
116 MethodHandle[] cache = TYPED_ACCESSORS.get(Object[].class);
117 cache[GETTER_INDEX] = OBJECT_ARRAY_GETTER = makeIntrinsic(getAccessor(Object[].class, false), Intrinsic.ARRAY_LOAD);
118 cache[SETTER_INDEX] = OBJECT_ARRAY_SETTER = makeIntrinsic(getAccessor(Object[].class, true), Intrinsic.ARRAY_STORE);
119
120 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_GETTER.internalMemberName()));
121 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_SETTER.internalMemberName()));
122 }
123
124 static int getElementI(int[] a, int i) { return a[i]; }
125 static long getElementJ(long[] a, int i) { return a[i]; }
126 static float getElementF(float[] a, int i) { return a[i]; }
127 static double getElementD(double[] a, int i) { return a[i]; }
128 static boolean getElementZ(boolean[] a, int i) { return a[i]; }
129 static byte getElementB(byte[] a, int i) { return a[i]; }
130 static short getElementS(short[] a, int i) { return a[i]; }
131 static char getElementC(char[] a, int i) { return a[i]; }
132 static Object getElementL(Object[] a, int i) { return a[i]; }
133
134 static void setElementI(int[] a, int i, int x) { a[i] = x; }
135 static void setElementJ(long[] a, int i, long x) { a[i] = x; }
136 static void setElementF(float[] a, int i, float x) { a[i] = x; }
137 static void setElementD(double[] a, int i, double x) { a[i] = x; }
138 static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; }
139 static void setElementB(byte[] a, int i, byte x) { a[i] = x; }
140 static void setElementS(short[] a, int i, short x) { a[i] = x; }
141 static void setElementC(char[] a, int i, char x) { a[i] = x; }
142 static void setElementL(Object[] a, int i, Object x) { a[i] = x; }
143
144 static String name(Class<?> arrayClass, boolean isSetter) {
145 Class<?> elemClass = arrayClass.getComponentType();
146 if (elemClass == null) throw newIllegalArgumentException("not an array", arrayClass);
147 return (!isSetter ? "getElement" : "setElement") + Wrapper.basicTypeChar(elemClass);
148 }
149 static MethodType type(Class<?> arrayClass, boolean isSetter) {
150 Class<?> elemClass = arrayClass.getComponentType();
151 Class<?> arrayArgClass = arrayClass;
152 if (!elemClass.isPrimitive()) {
153 arrayArgClass = Object[].class;
154 elemClass = Object.class;
155 }
156 return !isSetter ?
157 MethodType.methodType(elemClass, arrayArgClass, int.class) :
158 MethodType.methodType(void.class, arrayArgClass, int.class, elemClass);
159 }
160 static MethodType correctType(Class<?> arrayClass, boolean isSetter) {
161 Class<?> elemClass = arrayClass.getComponentType();
162 return !isSetter ?
163 MethodType.methodType(elemClass, arrayClass, int.class) :
164 MethodType.methodType(void.class, arrayClass, int.class, elemClass);
165 }
166 static MethodHandle getAccessor(Class<?> arrayClass, boolean isSetter) {
167 String name = name(arrayClass, isSetter);
168 MethodType type = type(arrayClass, isSetter);
169 try {
170 return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type);
171 } catch (ReflectiveOperationException ex) {
172 throw uncaughtException(ex);
173 }
174 }
175 }
176
177 /**
178 * Create a JVM-level adapter method handle to conform the given method
179 * handle to the similar newType, using only pairwise argument conversions.
180 * For each argument, convert incoming argument to the exact type needed.
181 * The argument conversions allowed are casting, boxing and unboxing,
182 * integral widening or narrowing, and floating point widening or narrowing.
183 * @param srcType required call type
184 * @param target original method handle
185 * @param strict if true, only asType conversions are allowed; if false, explicitCastArguments conversions allowed
186 * @param monobox if true, unboxing conversions are assumed to be exactly typed (Integer to int only, not long or double)
187 * @return an adapter to the original handle with the desired new type,
188 * or the original target if the types are already identical
189 * or null if the adaptation cannot be made
190 */
191 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
192 boolean strict, boolean monobox) {
193 MethodType dstType = target.type();
194 if (srcType == dstType)
195 return target;
196 return makePairwiseConvertByEditor(target, srcType, strict, monobox);
197 }
198
199 private static int countNonNull(Object[] array) {
200 int count = 0;
201 for (Object x : array) {
202 if (x != null) ++count;
203 }
204 return count;
205 }
206
207 static MethodHandle makePairwiseConvertByEditor(MethodHandle target, MethodType srcType,
208 boolean strict, boolean monobox) {
209 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
210 int convCount = countNonNull(convSpecs);
211 if (convCount == 0)
212 return target.viewAsType(srcType, strict);
213 MethodType basicSrcType = srcType.basicType();
214 MethodType midType = target.type().basicType();
215 BoundMethodHandle mh = target.rebind();
216 // FIXME: Reduce number of bindings when there is more than one Class conversion.
217 // FIXME: Reduce number of bindings when there are repeated conversions.
218 for (int i = 0; i < convSpecs.length-1; i++) {
219 Object convSpec = convSpecs[i];
220 if (convSpec == null) continue;
221 MethodHandle fn;
222 if (convSpec instanceof Class) {
223 fn = Lazy.MH_cast.bindTo(convSpec);
224 } else {
225 fn = (MethodHandle) convSpec;
226 }
227 Class<?> newType = basicSrcType.parameterType(i);
228 if (--convCount == 0)
229 midType = srcType;
230 else
231 midType = midType.changeParameterType(i, newType);
232 LambdaForm form2 = mh.editor().filterArgumentForm(1+i, BasicType.basicType(newType));
233 mh = mh.copyWithExtendL(midType, form2, fn);
234 mh = mh.rebind();
235 }
236 Object convSpec = convSpecs[convSpecs.length-1];
237 if (convSpec != null) {
238 MethodHandle fn;
239 if (convSpec instanceof Class) {
240 if (convSpec == void.class)
241 fn = null;
242 else
243 fn = Lazy.MH_cast.bindTo(convSpec);
244 } else {
245 fn = (MethodHandle) convSpec;
246 }
247 Class<?> newType = basicSrcType.returnType();
248 assert(--convCount == 0);
249 midType = srcType;
250 if (fn != null) {
251 mh = mh.rebind(); // rebind if too complex
252 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), false);
253 mh = mh.copyWithExtendL(midType, form2, fn);
254 } else {
255 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), true);
256 mh = mh.copyWith(midType, form2);
257 }
258 }
259 assert(convCount == 0);
260 assert(mh.type().equals(srcType));
261 return mh;
262 }
263
264 static MethodHandle makePairwiseConvertIndirect(MethodHandle target, MethodType srcType,
265 boolean strict, boolean monobox) {
266 assert(target.type().parameterCount() == srcType.parameterCount());
267 // Calculate extra arguments (temporaries) required in the names array.
268 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
269 final int INARG_COUNT = srcType.parameterCount();
270 int convCount = countNonNull(convSpecs);
271 boolean retConv = (convSpecs[INARG_COUNT] != null);
272 boolean retVoid = srcType.returnType() == void.class;
273 if (retConv && retVoid) {
274 convCount -= 1;
275 retConv = false;
276 }
277
278 final int IN_MH = 0;
279 final int INARG_BASE = 1;
280 final int INARG_LIMIT = INARG_BASE + INARG_COUNT;
281 final int NAME_LIMIT = INARG_LIMIT + convCount + 1;
282 final int RETURN_CONV = (!retConv ? -1 : NAME_LIMIT - 1);
283 final int OUT_CALL = (!retConv ? NAME_LIMIT : RETURN_CONV) - 1;
284 final int RESULT = (retVoid ? -1 : NAME_LIMIT - 1);
285
286 // Now build a LambdaForm.
287 MethodType lambdaType = srcType.basicType().invokerType();
288 Name[] names = arguments(NAME_LIMIT - INARG_LIMIT, lambdaType);
289
290 // Collect the arguments to the outgoing call, maybe with conversions:
291 final int OUTARG_BASE = 0; // target MH is Name.function, name Name.arguments[0]
292 Object[] outArgs = new Object[OUTARG_BASE + INARG_COUNT];
293
294 int nameCursor = INARG_LIMIT;
295 for (int i = 0; i < INARG_COUNT; i++) {
296 Object convSpec = convSpecs[i];
297 if (convSpec == null) {
298 // do nothing: difference is trivial
299 outArgs[OUTARG_BASE + i] = names[INARG_BASE + i];
300 continue;
301 }
302
303 Name conv;
304 if (convSpec instanceof Class) {
305 Class<?> convClass = (Class<?>) convSpec;
306 conv = new Name(Lazy.MH_cast, convClass, names[INARG_BASE + i]);
307 } else {
308 MethodHandle fn = (MethodHandle) convSpec;
309 conv = new Name(fn, names[INARG_BASE + i]);
310 }
311 assert(names[nameCursor] == null);
312 names[nameCursor++] = conv;
313 assert(outArgs[OUTARG_BASE + i] == null);
314 outArgs[OUTARG_BASE + i] = conv;
315 }
316
317 // Build argument array for the call.
318 assert(nameCursor == OUT_CALL);
319 names[OUT_CALL] = new Name(target, outArgs);
320
321 Object convSpec = convSpecs[INARG_COUNT];
322 if (!retConv) {
323 assert(OUT_CALL == names.length-1);
324 } else {
325 Name conv;
326 if (convSpec == void.class) {
327 conv = new Name(LambdaForm.constantZero(BasicType.basicType(srcType.returnType())));
328 } else if (convSpec instanceof Class) {
329 Class<?> convClass = (Class<?>) convSpec;
330 conv = new Name(Lazy.MH_cast, convClass, names[OUT_CALL]);
331 } else {
332 MethodHandle fn = (MethodHandle) convSpec;
333 if (fn.type().parameterCount() == 0)
334 conv = new Name(fn); // don't pass retval to void conversion
335 else
336 conv = new Name(fn, names[OUT_CALL]);
337 }
338 assert(names[RETURN_CONV] == null);
339 names[RETURN_CONV] = conv;
340 assert(RETURN_CONV == names.length-1);
341 }
342
343 LambdaForm form = new LambdaForm("convert", lambdaType.parameterCount(), names, RESULT);
344 return SimpleMethodHandle.make(srcType, form);
345 }
346
347 static Object[] computeValueConversions(MethodType srcType, MethodType dstType,
348 boolean strict, boolean monobox) {
349 final int INARG_COUNT = srcType.parameterCount();
350 Object[] convSpecs = new Object[INARG_COUNT+1];
351 for (int i = 0; i <= INARG_COUNT; i++) {
352 boolean isRet = (i == INARG_COUNT);
353 Class<?> src = isRet ? dstType.returnType() : srcType.parameterType(i);
354 Class<?> dst = isRet ? srcType.returnType() : dstType.parameterType(i);
355 if (!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)) {
356 convSpecs[i] = valueConversion(src, dst, strict, monobox);
357 }
358 }
359 return convSpecs;
360 }
361 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
362 boolean strict) {
363 return makePairwiseConvert(target, srcType, strict, /*monobox=*/ false);
364 }
365
366 /**
367 * Find a conversion function from the given source to the given destination.
368 * This conversion function will be used as a LF NamedFunction.
369 * Return a Class object if a simple cast is needed.
370 * Return void.class if void is involved.
371 */
372 static Object valueConversion(Class<?> src, Class<?> dst, boolean strict, boolean monobox) {
373 assert(!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)); // caller responsibility
374 if (dst == void.class)
375 return dst;
376 MethodHandle fn;
377 if (src.isPrimitive()) {
378 if (src == void.class) {
379 return void.class; // caller must recognize this specially
380 } else if (dst.isPrimitive()) {
381 // Examples: int->byte, byte->int, boolean->int (!strict)
382 fn = ValueConversions.convertPrimitive(src, dst);
383 } else {
384 // Examples: int->Integer, boolean->Object, float->Number
385 Wrapper wsrc = Wrapper.forPrimitiveType(src);
386 fn = ValueConversions.boxExact(wsrc);
387 assert(fn.type().parameterType(0) == wsrc.primitiveType());
388 assert(fn.type().returnType() == wsrc.wrapperType());
389 if (!VerifyType.isNullConversion(wsrc.wrapperType(), dst, strict)) {
390 // Corner case, such as int->Long, which will probably fail.
391 MethodType mt = MethodType.methodType(dst, src);
392 if (strict)
393 fn = fn.asType(mt);
394 else
395 fn = MethodHandleImpl.makePairwiseConvert(fn, mt, /*strict=*/ false);
396 }
397 }
398 } else if (dst.isPrimitive()) {
399 Wrapper wdst = Wrapper.forPrimitiveType(dst);
400 if (monobox || src == wdst.wrapperType()) {
401 // Use a strongly-typed unboxer, if possible.
402 fn = ValueConversions.unboxExact(wdst, strict);
403 } else {
404 // Examples: Object->int, Number->int, Comparable->int, Byte->int
405 // must include additional conversions
406 // src must be examined at runtime, to detect Byte, Character, etc.
407 fn = (strict
408 ? ValueConversions.unboxWiden(wdst)
409 : ValueConversions.unboxCast(wdst));
410 }
411 } else {
412 // Simple reference conversion.
413 // Note: Do not check for a class hierarchy relation
414 // between src and dst. In all cases a 'null' argument
415 // will pass the cast conversion.
416 return dst;
417 }
418 assert(fn.type().parameterCount() <= 1) : "pc"+Arrays.asList(src.getSimpleName(), dst.getSimpleName(), fn);
419 return fn;
420 }
421
422 static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
423 MethodType type = target.type();
424 int last = type.parameterCount() - 1;
425 if (type.parameterType(last) != arrayType)
426 target = target.asType(type.changeParameterType(last, arrayType));
427 target = target.asFixedArity(); // make sure this attribute is turned off
428 return new AsVarargsCollector(target, arrayType);
429 }
430
431 private static final class AsVarargsCollector extends DelegatingMethodHandle {
432 private final MethodHandle target;
433 private final Class<?> arrayType;
434 private @Stable MethodHandle asCollectorCache;
435
436 AsVarargsCollector(MethodHandle target, Class<?> arrayType) {
437 this(target.type(), target, arrayType);
438 }
439 AsVarargsCollector(MethodType type, MethodHandle target, Class<?> arrayType) {
440 super(type, target);
441 this.target = target;
442 this.arrayType = arrayType;
443 this.asCollectorCache = target.asCollector(arrayType, 0);
444 }
445
446 @Override
447 public boolean isVarargsCollector() {
448 return true;
449 }
450
451 @Override
452 protected MethodHandle getTarget() {
453 return target;
454 }
455
456 @Override
457 public MethodHandle asFixedArity() {
458 return target;
459 }
460
461 @Override
462 MethodHandle setVarargs(MemberName member) {
463 if (member.isVarargs()) return this;
464 return asFixedArity();
465 }
466
467 @Override
468 public MethodHandle asTypeUncached(MethodType newType) {
469 MethodType type = this.type();
470 int collectArg = type.parameterCount() - 1;
471 int newArity = newType.parameterCount();
472 if (newArity == collectArg+1 &&
473 type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
474 // if arity and trailing parameter are compatible, do normal thing
475 return asTypeCache = asFixedArity().asType(newType);
476 }
477 // check cache
478 MethodHandle acc = asCollectorCache;
479 if (acc != null && acc.type().parameterCount() == newArity)
480 return asTypeCache = acc.asType(newType);
481 // build and cache a collector
482 int arrayLength = newArity - collectArg;
483 MethodHandle collector;
484 try {
485 collector = asFixedArity().asCollector(arrayType, arrayLength);
486 assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
487 } catch (IllegalArgumentException ex) {
488 throw new WrongMethodTypeException("cannot build collector", ex);
489 }
490 asCollectorCache = collector;
491 return asTypeCache = collector.asType(newType);
492 }
493
494 @Override
495 boolean viewAsTypeChecks(MethodType newType, boolean strict) {
496 super.viewAsTypeChecks(newType, true);
497 if (strict) return true;
498 // extra assertion for non-strict checks:
499 assert (type().lastParameterType().getComponentType()
500 .isAssignableFrom(
501 newType.lastParameterType().getComponentType()))
502 : Arrays.asList(this, newType);
503 return true;
504 }
505 }
506
507 /** Factory method: Spread selected argument. */
508 static MethodHandle makeSpreadArguments(MethodHandle target,
509 Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
510 MethodType targetType = target.type();
511
512 for (int i = 0; i < spreadArgCount; i++) {
513 Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i);
514 if (arg == null) arg = Object.class;
515 targetType = targetType.changeParameterType(spreadArgPos + i, arg);
516 }
517 target = target.asType(targetType);
518
519 MethodType srcType = targetType
520 .replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType);
521 // Now build a LambdaForm.
522 MethodType lambdaType = srcType.invokerType();
523 Name[] names = arguments(spreadArgCount + 2, lambdaType);
524 int nameCursor = lambdaType.parameterCount();
525 int[] indexes = new int[targetType.parameterCount()];
526
527 for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) {
528 Class<?> src = lambdaType.parameterType(i);
529 if (i == spreadArgPos) {
530 // Spread the array.
531 MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType);
532 Name array = names[argIndex];
533 names[nameCursor++] = new Name(Lazy.NF_checkSpreadArgument, array, spreadArgCount);
534 for (int j = 0; j < spreadArgCount; i++, j++) {
535 indexes[i] = nameCursor;
536 names[nameCursor++] = new Name(aload, array, j);
537 }
538 } else if (i < indexes.length) {
539 indexes[i] = argIndex;
540 }
541 }
542 assert(nameCursor == names.length-1); // leave room for the final call
543
544 // Build argument array for the call.
545 Name[] targetArgs = new Name[targetType.parameterCount()];
546 for (int i = 0; i < targetType.parameterCount(); i++) {
547 int idx = indexes[i];
548 targetArgs[i] = names[idx];
549 }
550 names[names.length - 1] = new Name(target, (Object[]) targetArgs);
551
552 LambdaForm form = new LambdaForm("spread", lambdaType.parameterCount(), names);
553 return SimpleMethodHandle.make(srcType, form);
554 }
555
556 static void checkSpreadArgument(Object av, int n) {
557 if (av == null) {
558 if (n == 0) return;
559 } else if (av instanceof Object[]) {
560 int len = ((Object[])av).length;
561 if (len == n) return;
562 } else {
563 int len = java.lang.reflect.Array.getLength(av);
564 if (len == n) return;
565 }
566 // fall through to error:
567 throw newIllegalArgumentException("array is not of length "+n);
568 }
569
570 /**
571 * Pre-initialized NamedFunctions for bootstrapping purposes.
572 * Factored in an inner class to delay initialization until first usage.
573 */
574 static class Lazy {
575 private static final Class<?> MHI = MethodHandleImpl.class;
576 private static final Class<?> CLS = Class.class;
577
578 private static final MethodHandle[] ARRAYS;
579 private static final MethodHandle[] FILL_ARRAYS;
580
581 static final NamedFunction NF_checkSpreadArgument;
582 static final NamedFunction NF_guardWithCatch;
583 static final NamedFunction NF_throwException;
584 static final NamedFunction NF_profileBoolean;
585
586 static final MethodHandle MH_cast;
587 static final MethodHandle MH_selectAlternative;
588 static final MethodHandle MH_copyAsPrimitiveArray;
589 static final MethodHandle MH_fillNewTypedArray;
590 static final MethodHandle MH_fillNewArray;
591 static final MethodHandle MH_arrayIdentity;
592
593 static final MethodHandle MH_looper;
594 static final MethodHandle MH_countedLoopPred;
595 static final MethodHandle MH_countedLoopStep;
596 static final MethodHandle MH_iteratePred;
597 static final MethodHandle MH_initIterator;
598 static final MethodHandle MH_iterateNext;
599 static final MethodHandle MH_tryFinallyExec;
600 static final MethodHandle MH_tryFinallyVoidExec;
601
602 static {
603 ARRAYS = makeArrays();
604 FILL_ARRAYS = makeFillArrays();
605
606 try {
607 NF_checkSpreadArgument = new NamedFunction(MHI.getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
608 NF_guardWithCatch = new NamedFunction(MHI.getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class,
609 MethodHandle.class, Object[].class));
610 NF_throwException = new NamedFunction(MHI.getDeclaredMethod("throwException", Throwable.class));
611 NF_profileBoolean = new NamedFunction(MHI.getDeclaredMethod("profileBoolean", boolean.class, int[].class));
612
613 NF_checkSpreadArgument.resolve();
614 NF_guardWithCatch.resolve();
615 NF_throwException.resolve();
616 NF_profileBoolean.resolve();
617
618 MH_cast = IMPL_LOOKUP.findVirtual(CLS, "cast",
619 MethodType.methodType(Object.class, Object.class));
620 MH_copyAsPrimitiveArray = IMPL_LOOKUP.findStatic(MHI, "copyAsPrimitiveArray",
621 MethodType.methodType(Object.class, Wrapper.class, Object[].class));
622 MH_arrayIdentity = IMPL_LOOKUP.findStatic(MHI, "identity",
623 MethodType.methodType(Object[].class, Object[].class));
624 MH_fillNewArray = IMPL_LOOKUP.findStatic(MHI, "fillNewArray",
625 MethodType.methodType(Object[].class, Integer.class, Object[].class));
626 MH_fillNewTypedArray = IMPL_LOOKUP.findStatic(MHI, "fillNewTypedArray",
627 MethodType.methodType(Object[].class, Object[].class, Integer.class, Object[].class));
628
629 MH_selectAlternative = makeIntrinsic(
630 IMPL_LOOKUP.findStatic(MHI, "selectAlternative",
631 MethodType.methodType(MethodHandle.class, boolean.class, MethodHandle.class, MethodHandle.class)),
632 Intrinsic.SELECT_ALTERNATIVE);
633
634 MH_looper = IMPL_LOOKUP.findStatic(MHI, "looper", MethodType.methodType(Object.class, MethodHandle[].class,
635 MethodHandle[].class, MethodHandle[].class, MethodHandle[].class, int.class, int.class,
636 Object[].class));
637 MH_countedLoopPred = IMPL_LOOKUP.findStatic(MHI, "countedLoopPredicate",
638 MethodType.methodType(boolean.class, int.class, int.class));
639 MH_countedLoopStep = IMPL_LOOKUP.findStatic(MHI, "countedLoopStep", MethodType.methodType(int.class,
640 int.class, int.class));
641 MH_iteratePred = IMPL_LOOKUP.findStatic(MHI, "iteratePredicate", MethodType.methodType(boolean.class,
642 Iterator.class));
643 MH_initIterator = IMPL_LOOKUP.findStatic(MHI, "initIterator", MethodType.methodType(Iterator.class,
644 Iterable.class));
645 MH_iterateNext = IMPL_LOOKUP.findStatic(MHI, "iterateNext", MethodType.methodType(Object.class,
646 Iterator.class));
647 MH_tryFinallyExec = IMPL_LOOKUP.findStatic(MHI, "tryFinallyExecutor", MethodType.methodType(Object.class,
648 MethodHandle.class, MethodHandle.class, Object[].class));
649 MH_tryFinallyVoidExec = IMPL_LOOKUP.findStatic(MHI, "tryFinallyVoidExecutor",
650 MethodType.methodType(void.class, MethodHandle.class, MethodHandle.class, Object[].class));
651 } catch (ReflectiveOperationException ex) {
652 throw newInternalError(ex);
653 }
654 }
655 }
656
657 /** Factory method: Collect or filter selected argument(s). */
658 static MethodHandle makeCollectArguments(MethodHandle target,
659 MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) {
660 MethodType targetType = target.type(); // (a..., c, [b...])=>r
661 MethodType collectorType = collector.type(); // (b...)=>c
662 int collectArgCount = collectorType.parameterCount();
663 Class<?> collectValType = collectorType.returnType();
664 int collectValCount = (collectValType == void.class ? 0 : 1);
665 MethodType srcType = targetType // (a..., [b...])=>r
666 .dropParameterTypes(collectArgPos, collectArgPos+collectValCount);
667 if (!retainOriginalArgs) { // (a..., b...)=>r
668 srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterList());
669 }
670 // in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ]
671 // out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ]
672 // out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ]
673
674 // Now build a LambdaForm.
675 MethodType lambdaType = srcType.invokerType();
676 Name[] names = arguments(2, lambdaType);
677 final int collectNamePos = names.length - 2;
678 final int targetNamePos = names.length - 1;
679
680 Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount);
681 names[collectNamePos] = new Name(collector, (Object[]) collectorArgs);
682
683 // Build argument array for the target.
684 // Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ].
685 // Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ].
686 Name[] targetArgs = new Name[targetType.parameterCount()];
687 int inputArgPos = 1; // incoming LF args to copy to target
688 int targetArgPos = 0; // fill pointer for targetArgs
689 int chunk = collectArgPos; // |headArgs|
690 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
691 inputArgPos += chunk;
692 targetArgPos += chunk;
693 if (collectValType != void.class) {
694 targetArgs[targetArgPos++] = names[collectNamePos];
695 }
696 chunk = collectArgCount;
697 if (retainOriginalArgs) {
698 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
699 targetArgPos += chunk; // optionally pass on the collected chunk
700 }
701 inputArgPos += chunk;
702 chunk = targetArgs.length - targetArgPos; // all the rest
703 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
704 assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also
705 names[targetNamePos] = new Name(target, (Object[]) targetArgs);
706
707 LambdaForm form = new LambdaForm("collect", lambdaType.parameterCount(), names);
708 return SimpleMethodHandle.make(srcType, form);
709 }
710
711 @LambdaForm.Hidden
712 static
713 MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
714 if (testResult) {
715 return target;
716 } else {
717 return fallback;
718 }
719 }
720
721 // Intrinsified by C2. Counters are used during parsing to calculate branch frequencies.
722 @LambdaForm.Hidden
723 @jdk.internal.HotSpotIntrinsicCandidate
724 static
725 boolean profileBoolean(boolean result, int[] counters) {
726 // Profile is int[2] where [0] and [1] correspond to false and true occurrences respectively.
727 int idx = result ? 1 : 0;
728 try {
729 counters[idx] = Math.addExact(counters[idx], 1);
730 } catch (ArithmeticException e) {
731 // Avoid continuous overflow by halving the problematic count.
732 counters[idx] = counters[idx] / 2;
733 }
734 return result;
735 }
736
737 // Intrinsified by C2. Returns true if obj is a compile-time constant.
738 @LambdaForm.Hidden
739 @jdk.internal.HotSpotIntrinsicCandidate
740 static
741 boolean isCompileConstant(Object obj) {
742 return false;
743 }
744
745 static
746 MethodHandle makeGuardWithTest(MethodHandle test,
747 MethodHandle target,
748 MethodHandle fallback) {
749 MethodType type = target.type();
750 assert(test.type().equals(type.changeReturnType(boolean.class)) && fallback.type().equals(type));
751 MethodType basicType = type.basicType();
752 LambdaForm form = makeGuardWithTestForm(basicType);
753 BoundMethodHandle mh;
754 try {
755 if (PROFILE_GWT) {
756 int[] counts = new int[2];
757 mh = (BoundMethodHandle)
758 BoundMethodHandle.speciesData_LLLL().constructor().invokeBasic(type, form,
759 (Object) test, (Object) profile(target), (Object) profile(fallback), counts);
760 } else {
761 mh = (BoundMethodHandle)
762 BoundMethodHandle.speciesData_LLL().constructor().invokeBasic(type, form,
763 (Object) test, (Object) profile(target), (Object) profile(fallback));
764 }
765 } catch (Throwable ex) {
766 throw uncaughtException(ex);
767 }
768 assert(mh.type() == type);
769 return mh;
770 }
771
772
773 static
774 MethodHandle profile(MethodHandle target) {
775 if (DONT_INLINE_THRESHOLD >= 0) {
776 return makeBlockInliningWrapper(target);
777 } else {
778 return target;
779 }
780 }
781
782 /**
783 * Block inlining during JIT-compilation of a target method handle if it hasn't been invoked enough times.
784 * Corresponding LambdaForm has @DontInline when compiled into bytecode.
785 */
786 static
787 MethodHandle makeBlockInliningWrapper(MethodHandle target) {
788 LambdaForm lform;
789 if (DONT_INLINE_THRESHOLD > 0) {
790 lform = PRODUCE_BLOCK_INLINING_FORM.apply(target);
791 } else {
792 lform = PRODUCE_REINVOKER_FORM.apply(target);
793 }
794 return new CountingWrapper(target, lform,
795 PRODUCE_BLOCK_INLINING_FORM, PRODUCE_REINVOKER_FORM,
796 DONT_INLINE_THRESHOLD);
797 }
798
799 /** Constructs reinvoker lambda form which block inlining during JIT-compilation for a particular method handle */
800 private static final Function<MethodHandle, LambdaForm> PRODUCE_BLOCK_INLINING_FORM = new Function<MethodHandle, LambdaForm>() {
801 @Override
802 public LambdaForm apply(MethodHandle target) {
803 return DelegatingMethodHandle.makeReinvokerForm(target,
804 MethodTypeForm.LF_DELEGATE_BLOCK_INLINING, CountingWrapper.class, "reinvoker.dontInline", false,
805 DelegatingMethodHandle.NF_getTarget, CountingWrapper.NF_maybeStopCounting);
806 }
807 };
808
809 /** Constructs simple reinvoker lambda form for a particular method handle */
810 private static final Function<MethodHandle, LambdaForm> PRODUCE_REINVOKER_FORM = new Function<MethodHandle, LambdaForm>() {
811 @Override
812 public LambdaForm apply(MethodHandle target) {
813 return DelegatingMethodHandle.makeReinvokerForm(target,
814 MethodTypeForm.LF_DELEGATE, DelegatingMethodHandle.class, DelegatingMethodHandle.NF_getTarget);
815 }
816 };
817
818 /**
819 * Counting method handle. It has 2 states: counting and non-counting.
820 * It is in counting state for the first n invocations and then transitions to non-counting state.
821 * Behavior in counting and non-counting states is determined by lambda forms produced by
822 * countingFormProducer & nonCountingFormProducer respectively.
823 */
824 static class CountingWrapper extends DelegatingMethodHandle {
825 private final MethodHandle target;
826 private int count;
827 private Function<MethodHandle, LambdaForm> countingFormProducer;
828 private Function<MethodHandle, LambdaForm> nonCountingFormProducer;
829 private volatile boolean isCounting;
830
831 private CountingWrapper(MethodHandle target, LambdaForm lform,
832 Function<MethodHandle, LambdaForm> countingFromProducer,
833 Function<MethodHandle, LambdaForm> nonCountingFormProducer,
834 int count) {
835 super(target.type(), lform);
836 this.target = target;
837 this.count = count;
838 this.countingFormProducer = countingFromProducer;
839 this.nonCountingFormProducer = nonCountingFormProducer;
840 this.isCounting = (count > 0);
841 }
842
843 @Hidden
844 @Override
845 protected MethodHandle getTarget() {
846 return target;
847 }
848
849 @Override
850 public MethodHandle asTypeUncached(MethodType newType) {
851 MethodHandle newTarget = target.asType(newType);
852 MethodHandle wrapper;
853 if (isCounting) {
854 LambdaForm lform;
855 lform = countingFormProducer.apply(newTarget);
856 wrapper = new CountingWrapper(newTarget, lform, countingFormProducer, nonCountingFormProducer, DONT_INLINE_THRESHOLD);
857 } else {
858 wrapper = newTarget; // no need for a counting wrapper anymore
859 }
860 return (asTypeCache = wrapper);
861 }
862
863 boolean countDown() {
864 int c = count;
865 if (c <= 1) {
866 // Try to limit number of updates. MethodHandle.updateForm() doesn't guarantee LF update visibility.
867 if (isCounting) {
868 isCounting = false;
869 return true;
870 } else {
871 return false;
872 }
873 } else {
874 count = c - 1;
875 return false;
876 }
877 }
878
879 @Hidden
880 static void maybeStopCounting(Object o1) {
881 CountingWrapper wrapper = (CountingWrapper) o1;
882 if (wrapper.countDown()) {
883 // Reached invocation threshold. Replace counting behavior with a non-counting one.
884 LambdaForm lform = wrapper.nonCountingFormProducer.apply(wrapper.target);
885 lform.compileToBytecode(); // speed up warmup by avoiding LF interpretation again after transition
886 wrapper.updateForm(lform);
887 }
888 }
889
890 static final NamedFunction NF_maybeStopCounting;
891 static {
892 Class<?> THIS_CLASS = CountingWrapper.class;
893 try {
894 NF_maybeStopCounting = new NamedFunction(THIS_CLASS.getDeclaredMethod("maybeStopCounting", Object.class));
895 } catch (ReflectiveOperationException ex) {
896 throw newInternalError(ex);
897 }
898 }
899 }
900
901 static
902 LambdaForm makeGuardWithTestForm(MethodType basicType) {
903 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWT);
904 if (lform != null) return lform;
905 final int THIS_MH = 0; // the BMH_LLL
906 final int ARG_BASE = 1; // start of incoming arguments
907 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
908 int nameCursor = ARG_LIMIT;
909 final int GET_TEST = nameCursor++;
910 final int GET_TARGET = nameCursor++;
911 final int GET_FALLBACK = nameCursor++;
912 final int GET_COUNTERS = PROFILE_GWT ? nameCursor++ : -1;
913 final int CALL_TEST = nameCursor++;
914 final int PROFILE = (GET_COUNTERS != -1) ? nameCursor++ : -1;
915 final int TEST = nameCursor-1; // previous statement: either PROFILE or CALL_TEST
916 final int SELECT_ALT = nameCursor++;
917 final int CALL_TARGET = nameCursor++;
918 assert(CALL_TARGET == SELECT_ALT+1); // must be true to trigger IBG.emitSelectAlternative
919
920 MethodType lambdaType = basicType.invokerType();
921 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
922
923 BoundMethodHandle.SpeciesData data =
924 (GET_COUNTERS != -1) ? BoundMethodHandle.speciesData_LLLL()
925 : BoundMethodHandle.speciesData_LLL();
926 names[THIS_MH] = names[THIS_MH].withConstraint(data);
927 names[GET_TEST] = new Name(data.getterFunction(0), names[THIS_MH]);
928 names[GET_TARGET] = new Name(data.getterFunction(1), names[THIS_MH]);
929 names[GET_FALLBACK] = new Name(data.getterFunction(2), names[THIS_MH]);
930 if (GET_COUNTERS != -1) {
931 names[GET_COUNTERS] = new Name(data.getterFunction(3), names[THIS_MH]);
932 }
933 Object[] invokeArgs = Arrays.copyOfRange(names, 0, ARG_LIMIT, Object[].class);
934
935 // call test
936 MethodType testType = basicType.changeReturnType(boolean.class).basicType();
937 invokeArgs[0] = names[GET_TEST];
938 names[CALL_TEST] = new Name(testType, invokeArgs);
939
940 // profile branch
941 if (PROFILE != -1) {
942 names[PROFILE] = new Name(Lazy.NF_profileBoolean, names[CALL_TEST], names[GET_COUNTERS]);
943 }
944 // call selectAlternative
945 names[SELECT_ALT] = new Name(Lazy.MH_selectAlternative, names[TEST], names[GET_TARGET], names[GET_FALLBACK]);
946
947 // call target or fallback
948 invokeArgs[0] = names[SELECT_ALT];
949 names[CALL_TARGET] = new Name(basicType, invokeArgs);
950
951 lform = new LambdaForm("guard", lambdaType.parameterCount(), names, /*forceInline=*/true);
952
953 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWT, lform);
954 }
955
956 /**
957 * The LambdaForm shape for catchException combinator is the following:
958 * <blockquote><pre>{@code
959 * guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{
960 * t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L);
961 * t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L);
962 * t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L);
963 * t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L);
964 * t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L);
965 * t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L);
966 * t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L);
967 * t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I}
968 * }</pre></blockquote>
969 *
970 * argL0 and argL2 are target and catcher method handles. argL1 is exception class.
971 * argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[]
972 * (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()).
973 *
974 * Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms
975 * among catchException combinators with the same basic type.
976 */
977 private static LambdaForm makeGuardWithCatchForm(MethodType basicType) {
978 MethodType lambdaType = basicType.invokerType();
979
980 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC);
981 if (lform != null) {
982 return lform;
983 }
984 final int THIS_MH = 0; // the BMH_LLLLL
985 final int ARG_BASE = 1; // start of incoming arguments
986 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
987
988 int nameCursor = ARG_LIMIT;
989 final int GET_TARGET = nameCursor++;
990 final int GET_CLASS = nameCursor++;
991 final int GET_CATCHER = nameCursor++;
992 final int GET_COLLECT_ARGS = nameCursor++;
993 final int GET_UNBOX_RESULT = nameCursor++;
994 final int BOXED_ARGS = nameCursor++;
995 final int TRY_CATCH = nameCursor++;
996 final int UNBOX_RESULT = nameCursor++;
997
998 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
999
1000 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
1001 names[THIS_MH] = names[THIS_MH].withConstraint(data);
1002 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
1003 names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]);
1004 names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]);
1005 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]);
1006 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]);
1007
1008 // FIXME: rework argument boxing/result unboxing logic for LF interpretation
1009
1010 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
1011 MethodType collectArgsType = basicType.changeReturnType(Object.class);
1012 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
1013 Object[] args = new Object[invokeBasic.type().parameterCount()];
1014 args[0] = names[GET_COLLECT_ARGS];
1015 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
1016 names[BOXED_ARGS] = new Name(makeIntrinsic(invokeBasic, Intrinsic.GUARD_WITH_CATCH), args);
1017
1018 // t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L);
1019 Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]};
1020 names[TRY_CATCH] = new Name(Lazy.NF_guardWithCatch, gwcArgs);
1021
1022 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
1023 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
1024 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]};
1025 names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
1026
1027 lform = new LambdaForm("guardWithCatch", lambdaType.parameterCount(), names);
1028
1029 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform);
1030 }
1031
1032 static
1033 MethodHandle makeGuardWithCatch(MethodHandle target,
1034 Class<? extends Throwable> exType,
1035 MethodHandle catcher) {
1036 MethodType type = target.type();
1037 LambdaForm form = makeGuardWithCatchForm(type.basicType());
1038
1039 // Prepare auxiliary method handles used during LambdaForm interpretation.
1040 // Box arguments and wrap them into Object[]: ValueConversions.array().
1041 MethodType varargsType = type.changeReturnType(Object[].class);
1042 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
1043 // Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore().
1044 MethodHandle unboxResult;
1045 Class<?> rtype = type.returnType();
1046 if (rtype.isPrimitive()) {
1047 if (rtype == void.class) {
1048 unboxResult = ValueConversions.ignore();
1049 } else {
1050 Wrapper w = Wrapper.forPrimitiveType(type.returnType());
1051 unboxResult = ValueConversions.unboxExact(w);
1052 }
1053 } else {
1054 unboxResult = MethodHandles.identity(Object.class);
1055 }
1056
1057 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
1058 BoundMethodHandle mh;
1059 try {
1060 mh = (BoundMethodHandle)
1061 data.constructor().invokeBasic(type, form, (Object) target, (Object) exType, (Object) catcher,
1062 (Object) collectArgs, (Object) unboxResult);
1063 } catch (Throwable ex) {
1064 throw uncaughtException(ex);
1065 }
1066 assert(mh.type() == type);
1067 return mh;
1068 }
1069
1070 /**
1071 * Intrinsified during LambdaForm compilation
1072 * (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}).
1073 */
1074 @LambdaForm.Hidden
1075 static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher,
1076 Object... av) throws Throwable {
1077 // Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case.
1078 try {
1079 return target.asFixedArity().invokeWithArguments(av);
1080 } catch (Throwable t) {
1081 if (!exType.isInstance(t)) throw t;
1082 return catcher.asFixedArity().invokeWithArguments(prepend(t, av));
1083 }
1084 }
1085
1086 /** Prepend an element {@code elem} to an {@code array}. */
1087 @LambdaForm.Hidden
1088 private static Object[] prepend(Object elem, Object[] array) {
1089 Object[] newArray = new Object[array.length+1];
1090 newArray[0] = elem;
1091 System.arraycopy(array, 0, newArray, 1, array.length);
1092 return newArray;
1093 }
1094
1095 static
1096 MethodHandle throwException(MethodType type) {
1097 assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
1098 int arity = type.parameterCount();
1099 if (arity > 1) {
1100 MethodHandle mh = throwException(type.dropParameterTypes(1, arity));
1101 mh = MethodHandles.dropArguments(mh, 1, type.parameterList().subList(1, arity));
1102 return mh;
1103 }
1104 return makePairwiseConvert(Lazy.NF_throwException.resolvedHandle(), type, false, true);
1105 }
1106
1107 static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
1108
1109 static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
1110 static MethodHandle fakeMethodHandleInvoke(MemberName method) {
1111 int idx;
1112 assert(method.isMethodHandleInvoke());
1113 switch (method.getName()) {
1114 case "invoke": idx = 0; break;
1115 case "invokeExact": idx = 1; break;
1116 default: throw new InternalError(method.getName());
1117 }
1118 MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
1119 if (mh != null) return mh;
1120 MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
1121 MethodHandle.class, Object[].class);
1122 mh = throwException(type);
1123 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
1124 if (!method.getInvocationType().equals(mh.type()))
1125 throw new InternalError(method.toString());
1126 mh = mh.withInternalMemberName(method, false);
1127 mh = mh.asVarargsCollector(Object[].class);
1128 assert(method.isVarargs());
1129 FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
1130 return mh;
1131 }
1132
1133 /**
1134 * Create an alias for the method handle which, when called,
1135 * appears to be called from the same class loader and protection domain
1136 * as hostClass.
1137 * This is an expensive no-op unless the method which is called
1138 * is sensitive to its caller. A small number of system methods
1139 * are in this category, including Class.forName and Method.invoke.
1140 */
1141 static
1142 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1143 return BindCaller.bindCaller(mh, hostClass);
1144 }
1145
1146 // Put the whole mess into its own nested class.
1147 // That way we can lazily load the code and set up the constants.
1148 private static class BindCaller {
1149 static
1150 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1151 // Do not use this function to inject calls into system classes.
1152 if (hostClass == null
1153 || (hostClass.isArray() ||
1154 hostClass.isPrimitive() ||
1155 hostClass.getName().startsWith("java.") ||
1156 hostClass.getName().startsWith("sun."))) {
1157 throw new InternalError(); // does not happen, and should not anyway
1158 }
1159 // For simplicity, convert mh to a varargs-like method.
1160 MethodHandle vamh = prepareForInvoker(mh);
1161 // Cache the result of makeInjectedInvoker once per argument class.
1162 MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
1163 return restoreToType(bccInvoker.bindTo(vamh), mh, hostClass);
1164 }
1165
1166 private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
1167 Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null);
1168 if (hostClass.getClassLoader() != bcc.getClassLoader())
1169 throw new InternalError(hostClass.getName()+" (CL)");
1170 try {
1171 if (hostClass.getProtectionDomain() != bcc.getProtectionDomain())
1172 throw new InternalError(hostClass.getName()+" (PD)");
1173 } catch (SecurityException ex) {
1174 // Self-check was blocked by security manager. This is OK.
1175 // In fact the whole try body could be turned into an assertion.
1176 }
1177 try {
1178 MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class));
1179 init.invokeExact(); // force initialization of the class
1180 } catch (Throwable ex) {
1181 throw uncaughtException(ex);
1182 }
1183 MethodHandle bccInvoker;
1184 try {
1185 MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1186 bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT);
1187 } catch (ReflectiveOperationException ex) {
1188 throw uncaughtException(ex);
1189 }
1190 // Test the invoker, to ensure that it really injects into the right place.
1191 try {
1192 MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
1193 Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc});
1194 } catch (Throwable ex) {
1195 throw new InternalError(ex);
1196 }
1197 return bccInvoker;
1198 }
1199 private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() {
1200 @Override protected MethodHandle computeValue(Class<?> hostClass) {
1201 return makeInjectedInvoker(hostClass);
1202 }
1203 };
1204
1205 // Adapt mh so that it can be called directly from an injected invoker:
1206 private static MethodHandle prepareForInvoker(MethodHandle mh) {
1207 mh = mh.asFixedArity();
1208 MethodType mt = mh.type();
1209 int arity = mt.parameterCount();
1210 MethodHandle vamh = mh.asType(mt.generic());
1211 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1212 vamh = vamh.asSpreader(Object[].class, arity);
1213 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1214 return vamh;
1215 }
1216
1217 // Undo the adapter effect of prepareForInvoker:
1218 private static MethodHandle restoreToType(MethodHandle vamh,
1219 MethodHandle original,
1220 Class<?> hostClass) {
1221 MethodType type = original.type();
1222 MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount());
1223 MemberName member = original.internalMemberName();
1224 mh = mh.asType(type);
1225 mh = new WrappedMember(mh, type, member, original.isInvokeSpecial(), hostClass);
1226 return mh;
1227 }
1228
1229 private static final MethodHandle MH_checkCallerClass;
1230 static {
1231 final Class<?> THIS_CLASS = BindCaller.class;
1232 assert(checkCallerClass(THIS_CLASS, THIS_CLASS));
1233 try {
1234 MH_checkCallerClass = IMPL_LOOKUP
1235 .findStatic(THIS_CLASS, "checkCallerClass",
1236 MethodType.methodType(boolean.class, Class.class, Class.class));
1237 assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS, THIS_CLASS));
1238 } catch (Throwable ex) {
1239 throw new InternalError(ex);
1240 }
1241 }
1242
1243 @CallerSensitive
1244 private static boolean checkCallerClass(Class<?> expected, Class<?> expected2) {
1245 // This method is called via MH_checkCallerClass and so it's
1246 // correct to ask for the immediate caller here.
1247 Class<?> actual = Reflection.getCallerClass();
1248 if (actual != expected && actual != expected2)
1249 throw new InternalError("found "+actual.getName()+", expected "+expected.getName()
1250 +(expected == expected2 ? "" : ", or else "+expected2.getName()));
1251 return true;
1252 }
1253
1254 private static final byte[] T_BYTES;
1255 static {
1256 final Object[] values = {null};
1257 AccessController.doPrivileged(new PrivilegedAction<>() {
1258 public Void run() {
1259 try {
1260 Class<T> tClass = T.class;
1261 String tName = tClass.getName();
1262 String tResource = tName.substring(tName.lastIndexOf('.')+1)+".class";
1263 java.net.URLConnection uconn = tClass.getResource(tResource).openConnection();
1264 int len = uconn.getContentLength();
1265 byte[] bytes = new byte[len];
1266 try (java.io.InputStream str = uconn.getInputStream()) {
1267 int nr = str.read(bytes);
1268 if (nr != len) throw new java.io.IOException(tResource);
1269 }
1270 values[0] = bytes;
1271 } catch (java.io.IOException ex) {
1272 throw new InternalError(ex);
1273 }
1274 return null;
1275 }
1276 });
1277 T_BYTES = (byte[]) values[0];
1278 }
1279
1280 // The following class is used as a template for Unsafe.defineAnonymousClass:
1281 private static class T {
1282 static void init() { } // side effect: initializes this class
1283 static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
1284 return vamh.invokeExact(args);
1285 }
1286 }
1287 }
1288
1289
1290 /** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */
1291 private static final class WrappedMember extends DelegatingMethodHandle {
1292 private final MethodHandle target;
1293 private final MemberName member;
1294 private final Class<?> callerClass;
1295 private final boolean isInvokeSpecial;
1296
1297 private WrappedMember(MethodHandle target, MethodType type,
1298 MemberName member, boolean isInvokeSpecial,
1299 Class<?> callerClass) {
1300 super(type, target);
1301 this.target = target;
1302 this.member = member;
1303 this.callerClass = callerClass;
1304 this.isInvokeSpecial = isInvokeSpecial;
1305 }
1306
1307 @Override
1308 MemberName internalMemberName() {
1309 return member;
1310 }
1311 @Override
1312 Class<?> internalCallerClass() {
1313 return callerClass;
1314 }
1315 @Override
1316 boolean isInvokeSpecial() {
1317 return isInvokeSpecial;
1318 }
1319 @Override
1320 protected MethodHandle getTarget() {
1321 return target;
1322 }
1323 @Override
1324 public MethodHandle asTypeUncached(MethodType newType) {
1325 // This MH is an alias for target, except for the MemberName
1326 // Drop the MemberName if there is any conversion.
1327 return asTypeCache = target.asType(newType);
1328 }
1329 }
1330
1331 static MethodHandle makeWrappedMember(MethodHandle target, MemberName member, boolean isInvokeSpecial) {
1332 if (member.equals(target.internalMemberName()) && isInvokeSpecial == target.isInvokeSpecial())
1333 return target;
1334 return new WrappedMember(target, target.type(), member, isInvokeSpecial, null);
1335 }
1336
1337 /** Intrinsic IDs */
1338 /*non-public*/
1339 enum Intrinsic {
1340 SELECT_ALTERNATIVE,
1341 GUARD_WITH_CATCH,
1342 NEW_ARRAY,
1343 ARRAY_LOAD,
1344 ARRAY_STORE,
1345 IDENTITY,
1346 ZERO,
1347 NONE // no intrinsic associated
1348 }
1349
1350 /** Mark arbitrary method handle as intrinsic.
1351 * InvokerBytecodeGenerator uses this info to produce more efficient bytecode shape. */
1352 private static final class IntrinsicMethodHandle extends DelegatingMethodHandle {
1353 private final MethodHandle target;
1354 private final Intrinsic intrinsicName;
1355
1356 IntrinsicMethodHandle(MethodHandle target, Intrinsic intrinsicName) {
1357 super(target.type(), target);
1358 this.target = target;
1359 this.intrinsicName = intrinsicName;
1360 }
1361
1362 @Override
1363 protected MethodHandle getTarget() {
1364 return target;
1365 }
1366
1367 @Override
1368 Intrinsic intrinsicName() {
1369 return intrinsicName;
1370 }
1371
1372 @Override
1373 public MethodHandle asTypeUncached(MethodType newType) {
1374 // This MH is an alias for target, except for the intrinsic name
1375 // Drop the name if there is any conversion.
1376 return asTypeCache = target.asType(newType);
1377 }
1378
1379 @Override
1380 String internalProperties() {
1381 return super.internalProperties() +
1382 "\n& Intrinsic="+intrinsicName;
1383 }
1384
1385 @Override
1386 public MethodHandle asCollector(Class<?> arrayType, int arrayLength) {
1387 if (intrinsicName == Intrinsic.IDENTITY) {
1388 MethodType resultType = type().asCollectorType(arrayType, type().parameterCount() - 1, arrayLength);
1389 MethodHandle newArray = MethodHandleImpl.varargsArray(arrayType, arrayLength);
1390 return newArray.asType(resultType);
1391 }
1392 return super.asCollector(arrayType, arrayLength);
1393 }
1394 }
1395
1396 static MethodHandle makeIntrinsic(MethodHandle target, Intrinsic intrinsicName) {
1397 if (intrinsicName == target.intrinsicName())
1398 return target;
1399 return new IntrinsicMethodHandle(target, intrinsicName);
1400 }
1401
1402 static MethodHandle makeIntrinsic(MethodType type, LambdaForm form, Intrinsic intrinsicName) {
1403 return new IntrinsicMethodHandle(SimpleMethodHandle.make(type, form), intrinsicName);
1404 }
1405
1406 /// Collection of multiple arguments.
1407
1408 private static MethodHandle findCollector(String name, int nargs, Class<?> rtype, Class<?>... ptypes) {
1409 MethodType type = MethodType.genericMethodType(nargs)
1410 .changeReturnType(rtype)
1411 .insertParameterTypes(0, ptypes);
1412 try {
1413 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, name, type);
1414 } catch (ReflectiveOperationException ex) {
1415 return null;
1416 }
1417 }
1418
1419 private static final Object[] NO_ARGS_ARRAY = {};
1420 private static Object[] makeArray(Object... args) { return args; }
1421 private static Object[] array() { return NO_ARGS_ARRAY; }
1422 private static Object[] array(Object a0)
1423 { return makeArray(a0); }
1424 private static Object[] array(Object a0, Object a1)
1425 { return makeArray(a0, a1); }
1426 private static Object[] array(Object a0, Object a1, Object a2)
1427 { return makeArray(a0, a1, a2); }
1428 private static Object[] array(Object a0, Object a1, Object a2, Object a3)
1429 { return makeArray(a0, a1, a2, a3); }
1430 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1431 Object a4)
1432 { return makeArray(a0, a1, a2, a3, a4); }
1433 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1434 Object a4, Object a5)
1435 { return makeArray(a0, a1, a2, a3, a4, a5); }
1436 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1437 Object a4, Object a5, Object a6)
1438 { return makeArray(a0, a1, a2, a3, a4, a5, a6); }
1439 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1440 Object a4, Object a5, Object a6, Object a7)
1441 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7); }
1442 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1443 Object a4, Object a5, Object a6, Object a7,
1444 Object a8)
1445 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8); }
1446 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1447 Object a4, Object a5, Object a6, Object a7,
1448 Object a8, Object a9)
1449 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
1450
1451 private static final int ARRAYS_COUNT = 11;
1452
1453 private static MethodHandle[] makeArrays() {
1454 MethodHandle[] mhs = new MethodHandle[MAX_ARITY + 1];
1455 for (int i = 0; i < ARRAYS_COUNT; i++) {
1456 MethodHandle mh = findCollector("array", i, Object[].class);
1457 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1458 mhs[i] = mh;
1459 }
1460 assert(assertArrayMethodCount(mhs));
1461 return mhs;
1462 }
1463
1464 private static boolean assertArrayMethodCount(MethodHandle[] mhs) {
1465 assert(findCollector("array", ARRAYS_COUNT, Object[].class) == null);
1466 for (int i = 0; i < ARRAYS_COUNT; i++) {
1467 assert(mhs[i] != null);
1468 }
1469 return true;
1470 }
1471
1472 // filling versions of the above:
1473 // using Integer len instead of int len and no varargs to avoid bootstrapping problems
1474 private static Object[] fillNewArray(Integer len, Object[] /*not ...*/ args) {
1475 Object[] a = new Object[len];
1476 fillWithArguments(a, 0, args);
1477 return a;
1478 }
1479 private static Object[] fillNewTypedArray(Object[] example, Integer len, Object[] /*not ...*/ args) {
1480 Object[] a = Arrays.copyOf(example, len);
1481 assert(a.getClass() != Object[].class);
1482 fillWithArguments(a, 0, args);
1483 return a;
1484 }
1485 private static void fillWithArguments(Object[] a, int pos, Object... args) {
1486 System.arraycopy(args, 0, a, pos, args.length);
1487 }
1488 // using Integer pos instead of int pos to avoid bootstrapping problems
1489 private static Object[] fillArray(Integer pos, Object[] a, Object a0)
1490 { fillWithArguments(a, pos, a0); return a; }
1491 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1)
1492 { fillWithArguments(a, pos, a0, a1); return a; }
1493 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2)
1494 { fillWithArguments(a, pos, a0, a1, a2); return a; }
1495 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3)
1496 { fillWithArguments(a, pos, a0, a1, a2, a3); return a; }
1497 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1498 Object a4)
1499 { fillWithArguments(a, pos, a0, a1, a2, a3, a4); return a; }
1500 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1501 Object a4, Object a5)
1502 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5); return a; }
1503 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1504 Object a4, Object a5, Object a6)
1505 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6); return a; }
1506 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1507 Object a4, Object a5, Object a6, Object a7)
1508 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7); return a; }
1509 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1510 Object a4, Object a5, Object a6, Object a7,
1511 Object a8)
1512 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8); return a; }
1513 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1514 Object a4, Object a5, Object a6, Object a7,
1515 Object a8, Object a9)
1516 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); return a; }
1517
1518 private static final int FILL_ARRAYS_COUNT = 11; // current number of fillArray methods
1519
1520 private static MethodHandle[] makeFillArrays() {
1521 MethodHandle[] mhs = new MethodHandle[FILL_ARRAYS_COUNT];
1522 mhs[0] = null; // there is no empty fill; at least a0 is required
1523 for (int i = 1; i < FILL_ARRAYS_COUNT; i++) {
1524 MethodHandle mh = findCollector("fillArray", i, Object[].class, Integer.class, Object[].class);
1525 mhs[i] = mh;
1526 }
1527 assert(assertFillArrayMethodCount(mhs));
1528 return mhs;
1529 }
1530
1531 private static boolean assertFillArrayMethodCount(MethodHandle[] mhs) {
1532 assert(findCollector("fillArray", FILL_ARRAYS_COUNT, Object[].class, Integer.class, Object[].class) == null);
1533 for (int i = 1; i < FILL_ARRAYS_COUNT; i++) {
1534 assert(mhs[i] != null);
1535 }
1536 return true;
1537 }
1538
1539 private static Object copyAsPrimitiveArray(Wrapper w, Object... boxes) {
1540 Object a = w.makeArray(boxes.length);
1541 w.copyArrayUnboxing(boxes, 0, a, 0, boxes.length);
1542 return a;
1543 }
1544
1545 /** Return a method handle that takes the indicated number of Object
1546 * arguments and returns an Object array of them, as if for varargs.
1547 */
1548 static MethodHandle varargsArray(int nargs) {
1549 MethodHandle mh = Lazy.ARRAYS[nargs];
1550 if (mh != null) return mh;
1551 mh = buildVarargsArray(Lazy.MH_fillNewArray, Lazy.MH_arrayIdentity, nargs);
1552 assert(assertCorrectArity(mh, nargs));
1553 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1554 return Lazy.ARRAYS[nargs] = mh;
1555 }
1556
1557 private static boolean assertCorrectArity(MethodHandle mh, int arity) {
1558 assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh;
1559 return true;
1560 }
1561
1562 // Array identity function (used as Lazy.MH_arrayIdentity).
1563 static <T> T[] identity(T[] x) {
1564 return x;
1565 }
1566
1567 private static MethodHandle buildVarargsArray(MethodHandle newArray, MethodHandle finisher, int nargs) {
1568 // Build up the result mh as a sequence of fills like this:
1569 // finisher(fill(fill(newArrayWA(23,x1..x10),10,x11..x20),20,x21..x23))
1570 // The various fill(_,10*I,___*[J]) are reusable.
1571 int leftLen = Math.min(nargs, LEFT_ARGS); // absorb some arguments immediately
1572 int rightLen = nargs - leftLen;
1573 MethodHandle leftCollector = newArray.bindTo(nargs);
1574 leftCollector = leftCollector.asCollector(Object[].class, leftLen);
1575 MethodHandle mh = finisher;
1576 if (rightLen > 0) {
1577 MethodHandle rightFiller = fillToRight(LEFT_ARGS + rightLen);
1578 if (mh == Lazy.MH_arrayIdentity)
1579 mh = rightFiller;
1580 else
1581 mh = MethodHandles.collectArguments(mh, 0, rightFiller);
1582 }
1583 if (mh == Lazy.MH_arrayIdentity)
1584 mh = leftCollector;
1585 else
1586 mh = MethodHandles.collectArguments(mh, 0, leftCollector);
1587 return mh;
1588 }
1589
1590 private static final int LEFT_ARGS = FILL_ARRAYS_COUNT - 1;
1591 private static final MethodHandle[] FILL_ARRAY_TO_RIGHT = new MethodHandle[MAX_ARITY+1];
1592 /** fill_array_to_right(N).invoke(a, argL..arg[N-1])
1593 * fills a[L]..a[N-1] with corresponding arguments,
1594 * and then returns a. The value L is a global constant (LEFT_ARGS).
1595 */
1596 private static MethodHandle fillToRight(int nargs) {
1597 MethodHandle filler = FILL_ARRAY_TO_RIGHT[nargs];
1598 if (filler != null) return filler;
1599 filler = buildFiller(nargs);
1600 assert(assertCorrectArity(filler, nargs - LEFT_ARGS + 1));
1601 return FILL_ARRAY_TO_RIGHT[nargs] = filler;
1602 }
1603 private static MethodHandle buildFiller(int nargs) {
1604 if (nargs <= LEFT_ARGS)
1605 return Lazy.MH_arrayIdentity; // no args to fill; return the array unchanged
1606 // we need room for both mh and a in mh.invoke(a, arg*[nargs])
1607 final int CHUNK = LEFT_ARGS;
1608 int rightLen = nargs % CHUNK;
1609 int midLen = nargs - rightLen;
1610 if (rightLen == 0) {
1611 midLen = nargs - (rightLen = CHUNK);
1612 if (FILL_ARRAY_TO_RIGHT[midLen] == null) {
1613 // build some precursors from left to right
1614 for (int j = LEFT_ARGS % CHUNK; j < midLen; j += CHUNK)
1615 if (j > LEFT_ARGS) fillToRight(j);
1616 }
1617 }
1618 if (midLen < LEFT_ARGS) rightLen = nargs - (midLen = LEFT_ARGS);
1619 assert(rightLen > 0);
1620 MethodHandle midFill = fillToRight(midLen); // recursive fill
1621 MethodHandle rightFill = Lazy.FILL_ARRAYS[rightLen].bindTo(midLen); // [midLen..nargs-1]
1622 assert(midFill.type().parameterCount() == 1 + midLen - LEFT_ARGS);
1623 assert(rightFill.type().parameterCount() == 1 + rightLen);
1624
1625 // Combine the two fills:
1626 // right(mid(a, x10..x19), x20..x23)
1627 // The final product will look like this:
1628 // right(mid(newArrayLeft(24, x0..x9), x10..x19), x20..x23)
1629 if (midLen == LEFT_ARGS)
1630 return rightFill;
1631 else
1632 return MethodHandles.collectArguments(rightFill, 0, midFill);
1633 }
1634
1635 // Type-polymorphic version of varargs maker.
1636 private static final ClassValue<MethodHandle[]> TYPED_COLLECTORS
1637 = new ClassValue<MethodHandle[]>() {
1638 @Override
1639 protected MethodHandle[] computeValue(Class<?> type) {
1640 return new MethodHandle[256];
1641 }
1642 };
1643
1644 static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM
1645
1646 /** Return a method handle that takes the indicated number of
1647 * typed arguments and returns an array of them.
1648 * The type argument is the array type.
1649 */
1650 static MethodHandle varargsArray(Class<?> arrayType, int nargs) {
1651 Class<?> elemType = arrayType.getComponentType();
1652 if (elemType == null) throw new IllegalArgumentException("not an array: "+arrayType);
1653 // FIXME: Need more special casing and caching here.
1654 if (nargs >= MAX_JVM_ARITY/2 - 1) {
1655 int slots = nargs;
1656 final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH
1657 if (slots <= MAX_ARRAY_SLOTS && elemType.isPrimitive())
1658 slots *= Wrapper.forPrimitiveType(elemType).stackSlots();
1659 if (slots > MAX_ARRAY_SLOTS)
1660 throw new IllegalArgumentException("too many arguments: "+arrayType.getSimpleName()+", length "+nargs);
1661 }
1662 if (elemType == Object.class)
1663 return varargsArray(nargs);
1664 // other cases: primitive arrays, subtypes of Object[]
1665 MethodHandle cache[] = TYPED_COLLECTORS.get(elemType);
1666 MethodHandle mh = nargs < cache.length ? cache[nargs] : null;
1667 if (mh != null) return mh;
1668 if (nargs == 0) {
1669 Object example = java.lang.reflect.Array.newInstance(arrayType.getComponentType(), 0);
1670 mh = MethodHandles.constant(arrayType, example);
1671 } else if (elemType.isPrimitive()) {
1672 MethodHandle builder = Lazy.MH_fillNewArray;
1673 MethodHandle producer = buildArrayProducer(arrayType);
1674 mh = buildVarargsArray(builder, producer, nargs);
1675 } else {
1676 Class<? extends Object[]> objArrayType = arrayType.asSubclass(Object[].class);
1677 Object[] example = Arrays.copyOf(NO_ARGS_ARRAY, 0, objArrayType);
1678 MethodHandle builder = Lazy.MH_fillNewTypedArray.bindTo(example);
1679 MethodHandle producer = Lazy.MH_arrayIdentity; // must be weakly typed
1680 mh = buildVarargsArray(builder, producer, nargs);
1681 }
1682 mh = mh.asType(MethodType.methodType(arrayType, Collections.<Class<?>>nCopies(nargs, elemType)));
1683 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1684 assert(assertCorrectArity(mh, nargs));
1685 if (nargs < cache.length)
1686 cache[nargs] = mh;
1687 return mh;
1688 }
1689
1690 private static MethodHandle buildArrayProducer(Class<?> arrayType) {
1691 Class<?> elemType = arrayType.getComponentType();
1692 assert(elemType.isPrimitive());
1693 return Lazy.MH_copyAsPrimitiveArray.bindTo(Wrapper.forPrimitiveType(elemType));
1694 }
1695
1696 /*non-public*/ static void assertSame(Object mh1, Object mh2) {
1697 if (mh1 != mh2) {
1698 String msg = String.format("mh1 != mh2: mh1 = %s (form: %s); mh2 = %s (form: %s)",
1699 mh1, ((MethodHandle)mh1).form,
1700 mh2, ((MethodHandle)mh2).form);
1701 throw newInternalError(msg);
1702 }
1703 }
1704
1705 /**
1706 * Assembles a loop method handle from the given handles and type information. This works by binding and configuring
1707 * the {@linkplain #looper(MethodHandle[], MethodHandle[], MethodHandle[], MethodHandle[], int, int, Object[]) "most
1708 * generic loop"}.
1709 *
1710 * @param tloop the return type of the loop.
1711 * @param targs types of the arguments to be passed to the loop.
1712 * @param tvars types of loop-local variables.
1713 * @param init sanitized array of initializers for loop-local variables.
1714 * @param step sanitited array of loop bodies.
1715 * @param pred sanitized array of predicates.
1716 * @param fini sanitized array of loop finalizers.
1717 *
1718 * @return a handle that, when invoked, will execute the loop.
1719 */
1720 static MethodHandle makeLoop(Class<?> tloop, List<Class<?>> targs, List<Class<?>> tvars, List<MethodHandle> init,
1721 List<MethodHandle> step, List<MethodHandle> pred, List<MethodHandle> fini) {
1722 MethodHandle[] ainit = toArrayArgs(init).toArray(MH_ARRAY_SENTINEL);
1723 MethodHandle[] astep = toArrayArgs(step).toArray(MH_ARRAY_SENTINEL);
1724 MethodHandle[] apred = toArrayArgs(pred).toArray(MH_ARRAY_SENTINEL);
1725 MethodHandle[] afini = toArrayArgs(fini).toArray(MH_ARRAY_SENTINEL);
1726
1727 MethodHandle l = MethodHandleImpl.Lazy.MH_looper;
1728
1729 // Bind the statically known arguments.
1730 l = MethodHandles.insertArguments(l, 0, ainit, astep, apred, afini, tvars.size(), targs.size());
1731
1732 // Turn the args array into an argument list.
1733 l = l.asCollector(Object[].class, targs.size());
1734
1735 // Finally, make loop type.
1736 MethodType loopType = MethodType.methodType(tloop, targs);
1737 l = l.asType(loopType);
1738
1739 return l;
1740 }
1741
1742 private static final MethodHandle[] MH_ARRAY_SENTINEL = {};
1743
1744 /**
1745 * Converts all handles in the {@code hs} array to handles that accept an array of arguments.
1746 *
1747 * @param hs method handles to be converted.
1748 *
1749 * @return the {@code hs} array, with all method handles therein converted.
1750 */
1751 static List<MethodHandle> toArrayArgs(List<MethodHandle> hs) {
1752 return hs.stream().map(h -> h.asSpreader(Object[].class, h.type().parameterCount())).collect(Collectors.toList());
1753 }
1754
1755 /**
1756 * This method embodies the most generic loop for use by {@link MethodHandles#loop(MethodHandle[][])}. A handle on
1757 * it will be transformed into a handle on a concrete loop instantiation by {@link #makeLoop}.
1758 *
1759 * @param init loop-local variable initializers.
1760 * @param step bodies.
1761 * @param pred predicates.
1762 * @param fini finalizers.
1763 * @param varSize number of loop-local variables.
1764 * @param nArgs number of arguments passed to the loop.
1765 * @param args arguments to the loop invocation.
1766 *
1767 * @return the result of executing the loop.
1768 */
1769 static Object looper(MethodHandle[] init, MethodHandle[] step, MethodHandle[] pred, MethodHandle[] fini,
1770 int varSize, int nArgs, Object[] args) throws Throwable {
1771 Object[] varsAndArgs = new Object[varSize + nArgs];
1772 for (int i = 0, v = 0; i < init.length; ++i) {
1773 if (init[i].type().returnType() == void.class) {
1774 init[i].invoke(args);
1775 } else {
1776 varsAndArgs[v++] = init[i].invoke(args);
1777 }
1778 }
1779 System.arraycopy(args, 0, varsAndArgs, varSize, nArgs);
1780 final int nSteps = step.length;
1781 for (; ; ) {
1782 for (int i = 0, v = 0; i < nSteps; ++i) {
1783 MethodHandle p = pred[i];
1784 MethodHandle s = step[i];
1785 MethodHandle f = fini[i];
1786 if (s.type().returnType() == void.class) {
1787 s.invoke(varsAndArgs);
1788 } else {
1789 varsAndArgs[v++] = s.invoke(varsAndArgs);
1790 }
1791 if (!(boolean) p.invoke(varsAndArgs)) {
1792 return f.invoke(varsAndArgs);
1793 }
1794 }
1795 }
1796 }
1797
1798 /**
1799 * This method is bound as the predicate in {@linkplain MethodHandles#countedLoop(MethodHandle, MethodHandle,
1800 * MethodHandle) counting loops}.
1801 *
1802 * @param counter the counter parameter, passed in during loop execution.
1803 * @param limit the upper bound of the parameter, statically bound at loop creation time.
1804 *
1805 * @return whether the counter has reached the limit.
1806 */
1807 static boolean countedLoopPredicate(int counter, int limit) {
1808 return counter <= limit;
1809 }
1810
1811 /**
1812 * This method is bound as the step function in {@linkplain MethodHandles#countedLoop(MethodHandle, MethodHandle,
1813 * MethodHandle) counting loops} to increment the counter.
1814 *
1815 * @param counter the loop counter.
1816 *
1817 * @return the loop counter incremented by 1.
1818 */
1819 static int countedLoopStep(int counter, int limit) {
1820 return counter + 1;
1821 }
1822
1823 /**
1824 * This is bound to initialize the loop-local iterator in {@linkplain MethodHandles#iteratedLoop iterating loops}.
1825 *
1826 * @param it the {@link Iterable} over which the loop iterates.
1827 *
1828 * @return an {@link Iterator} over the argument's elements.
1829 */
1830 static Iterator<?> initIterator(Iterable<?> it) {
1831 return it.iterator();
1832 }
1833
1834 /**
1835 * This method is bound as the predicate in {@linkplain MethodHandles#iteratedLoop iterating loops}.
1836 *
1837 * @param it the iterator to be checked.
1838 *
1839 * @return {@code true} iff there are more elements to iterate over.
1840 */
1841 static boolean iteratePredicate(Iterator<?> it) {
1842 return it.hasNext();
1843 }
1844
1845 /**
1846 * This method is bound as the step for retrieving the current value from the iterator in {@linkplain
1847 * MethodHandles#iteratedLoop iterating loops}.
1848 *
1849 * @param it the iterator.
1850 *
1851 * @return the next element from the iterator.
1852 */
1853 static Object iterateNext(Iterator<?> it) {
1854 return it.next();
1855 }
1856
1857 /**
1858 * Makes a {@code try-finally} handle that conforms to the type constraints.
1859 *
1860 * @param target the target to execute in a {@code try-finally} block.
1861 * @param cleanup the cleanup to execute in the {@code finally} block.
1862 * @param type the result type of the entire construct.
1863 * @param argTypes the types of the arguments.
1864 *
1865 * @return a handle on the constructed {@code try-finally} block.
1866 */
1867 static MethodHandle makeTryFinally(MethodHandle target, MethodHandle cleanup, Class<?> type, List<Class<?>> argTypes) {
1868 MethodHandle tf = isVoid(type) ?
1869 MethodHandleImpl.Lazy.MH_tryFinallyVoidExec : MethodHandleImpl.Lazy.MH_tryFinallyExec;
1870
1871 // Bind the statically known arguments.
1872 tf = MethodHandles.insertArguments(tf, 0, target, cleanup);
1873
1874 // Turn the args array into an argument list.
1875 tf = tf.asCollector(Object[].class, argTypes.size());
1876
1877 // Finally, make try-finally type.
1878 MethodType tfType = MethodType.methodType(type, argTypes);
1879 tf = tf.asType(tfType);
1880
1881 return tf;
1882 }
1883
1884 static boolean isVoid(Class<?> t) {
1885 return t == void.class || t == Void.class;
1886 }
1887
1888 /**
1889 * A method that will be bound during construction of a {@code try-finally} handle with non-{@code void} return type
1890 * by {@link MethodHandles#tryFinally(MethodHandle, MethodHandle)}.
1891 *
1892 * @param target the handle to wrap in a {@code try-finally} block. This will be bound.
1893 * @param cleanup the handle to run in any case before returning. This will be bound.
1894 * @param args the arguments to the call. These will remain as the argument list.
1895 *
1896 * @return whatever the execution of the {@code target} returned (it may have been modified by the execution of
1897 * {@code cleanup}).
1898 * @throws Throwable in case anything is thrown by the execution of {@code target}, the {@link Throwable} will be
1899 * passed to the {@code cleanup} handle, which may decide to throw any exception it sees fit.
1900 */
1901 static Object tryFinallyExecutor(MethodHandle target, MethodHandle cleanup, Object[] args) throws Throwable {
1902 Throwable t = null;
1903 Object r = null;
1904 try {
1905 r = target.invoke(args);
1906 } catch (Throwable thrown) {
1907 t = thrown;
1908 throw t;
1909 } finally {
1910 r = cleanup.invoke(t, r, args);
1911 }
1912 return r;
1913 }
1914
1915 /**
1916 * A method that will be bound during construction of a {@code try-finally} handle with {@code void} return type by
1917 * {@link MethodHandles#tryFinally(MethodHandle, MethodHandle)}.
1918 *
1919 * @param target the handle to wrap in a {@code try-finally} block. This will be bound.
1920 * @param cleanup the handle to run in any case before returning. This will be bound.
1921 * @param args the arguments to the call. These will remain as the argument list.
1922 *
1923 * @throws Throwable in case anything is thrown by the execution of {@code target}, the {@link Throwable} will be
1924 * passed to the {@code cleanup} handle, which may decide to throw any exception it sees fit.
1925 */
1926 static void tryFinallyVoidExecutor(MethodHandle target, MethodHandle cleanup, Object[] args) throws Throwable {
1927 Throwable t = null;
1928 try {
1929 target.invoke(args);
1930 } catch (Throwable thrown) {
1931 t = thrown;
1932 throw t;
1933 } finally {
1934 cleanup.invoke(t, args);
1935 }
1936 }
1937 }