1 /*
2 * Copyright (c) 2008, 2016, 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
36 import jdk.internal.reflect.CallerSensitive;
37 import jdk.internal.reflect.Reflection;
38 import jdk.internal.vm.annotation.Stable;
39 import sun.invoke.empty.Empty;
40 import sun.invoke.util.ValueConversions;
41 import sun.invoke.util.VerifyType;
42 import sun.invoke.util.Wrapper;
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 MethodHandle makeArrayElementAccessor(Class<?> arrayClass, boolean isSetter) {
69 if (arrayClass == Object[].class)
70 return (isSetter ? ArrayAccessor.OBJECT_ARRAY_SETTER : ArrayAccessor.OBJECT_ARRAY_GETTER);
71 if (!arrayClass.isArray())
72 throw newIllegalArgumentException("not an array: "+arrayClass);
73 MethodHandle[] cache = ArrayAccessor.TYPED_ACCESSORS.get(arrayClass);
74 int cacheIndex = (isSetter ? ArrayAccessor.SETTER_INDEX : ArrayAccessor.GETTER_INDEX);
75 MethodHandle mh = cache[cacheIndex];
76 if (mh != null) return mh;
77 mh = ArrayAccessor.getAccessor(arrayClass, isSetter);
78 MethodType correctType = ArrayAccessor.correctType(arrayClass, isSetter);
79 if (mh.type() != correctType) {
80 assert(mh.type().parameterType(0) == Object[].class);
81 assert((isSetter ? mh.type().parameterType(2) : mh.type().returnType()) == Object.class);
82 assert(isSetter || correctType.parameterType(0).getComponentType() == correctType.returnType());
83 // safe to view non-strictly, because element type follows from array type
84 mh = mh.viewAsType(correctType, false);
85 }
86 mh = makeIntrinsic(mh, (isSetter ? Intrinsic.ARRAY_STORE : Intrinsic.ARRAY_LOAD));
87 // Atomically update accessor cache.
88 synchronized(cache) {
89 if (cache[cacheIndex] == null) {
90 cache[cacheIndex] = mh;
91 } else {
92 // Throw away newly constructed accessor and use cached version.
93 mh = cache[cacheIndex];
94 }
95 }
96 return mh;
97 }
98
99 static final class ArrayAccessor {
100 /// Support for array element access
101 static final int GETTER_INDEX = 0, SETTER_INDEX = 1, INDEX_LIMIT = 2;
102 static final ClassValue<MethodHandle[]> TYPED_ACCESSORS
103 = new ClassValue<MethodHandle[]>() {
104 @Override
105 protected MethodHandle[] computeValue(Class<?> type) {
106 return new MethodHandle[INDEX_LIMIT];
107 }
108 };
109 static final MethodHandle OBJECT_ARRAY_GETTER, OBJECT_ARRAY_SETTER;
110 static {
111 MethodHandle[] cache = TYPED_ACCESSORS.get(Object[].class);
112 cache[GETTER_INDEX] = OBJECT_ARRAY_GETTER = makeIntrinsic(getAccessor(Object[].class, false), Intrinsic.ARRAY_LOAD);
113 cache[SETTER_INDEX] = OBJECT_ARRAY_SETTER = makeIntrinsic(getAccessor(Object[].class, true), Intrinsic.ARRAY_STORE);
114
115 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_GETTER.internalMemberName()));
116 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_SETTER.internalMemberName()));
117 }
118
119 static int getElementI(int[] a, int i) { return a[i]; }
120 static long getElementJ(long[] a, int i) { return a[i]; }
121 static float getElementF(float[] a, int i) { return a[i]; }
122 static double getElementD(double[] a, int i) { return a[i]; }
123 static boolean getElementZ(boolean[] a, int i) { return a[i]; }
124 static byte getElementB(byte[] a, int i) { return a[i]; }
125 static short getElementS(short[] a, int i) { return a[i]; }
126 static char getElementC(char[] a, int i) { return a[i]; }
127 static Object getElementL(Object[] a, int i) { return a[i]; }
128
129 static void setElementI(int[] a, int i, int x) { a[i] = x; }
130 static void setElementJ(long[] a, int i, long x) { a[i] = x; }
131 static void setElementF(float[] a, int i, float x) { a[i] = x; }
132 static void setElementD(double[] a, int i, double x) { a[i] = x; }
133 static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; }
134 static void setElementB(byte[] a, int i, byte x) { a[i] = x; }
135 static void setElementS(short[] a, int i, short x) { a[i] = x; }
136 static void setElementC(char[] a, int i, char x) { a[i] = x; }
137 static void setElementL(Object[] a, int i, Object x) { a[i] = x; }
138
139 static String name(Class<?> arrayClass, boolean isSetter) {
140 Class<?> elemClass = arrayClass.getComponentType();
141 if (elemClass == null) throw newIllegalArgumentException("not an array", arrayClass);
142 return (!isSetter ? "getElement" : "setElement") + Wrapper.basicTypeChar(elemClass);
143 }
144 static MethodType type(Class<?> arrayClass, boolean isSetter) {
145 Class<?> elemClass = arrayClass.getComponentType();
146 Class<?> arrayArgClass = arrayClass;
147 if (!elemClass.isPrimitive()) {
148 arrayArgClass = Object[].class;
149 elemClass = Object.class;
150 }
151 return !isSetter ?
152 MethodType.methodType(elemClass, arrayArgClass, int.class) :
153 MethodType.methodType(void.class, arrayArgClass, int.class, elemClass);
154 }
155 static MethodType correctType(Class<?> arrayClass, boolean isSetter) {
156 Class<?> elemClass = arrayClass.getComponentType();
157 return !isSetter ?
158 MethodType.methodType(elemClass, arrayClass, int.class) :
159 MethodType.methodType(void.class, arrayClass, int.class, elemClass);
160 }
161 static MethodHandle getAccessor(Class<?> arrayClass, boolean isSetter) {
162 String name = name(arrayClass, isSetter);
163 MethodType type = type(arrayClass, isSetter);
164 try {
165 return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type);
166 } catch (ReflectiveOperationException ex) {
167 throw uncaughtException(ex);
168 }
169 }
170 }
171
172 /**
173 * Create a JVM-level adapter method handle to conform the given method
174 * handle to the similar newType, using only pairwise argument conversions.
175 * For each argument, convert incoming argument to the exact type needed.
176 * The argument conversions allowed are casting, boxing and unboxing,
177 * integral widening or narrowing, and floating point widening or narrowing.
178 * @param srcType required call type
179 * @param target original method handle
180 * @param strict if true, only asType conversions are allowed; if false, explicitCastArguments conversions allowed
181 * @param monobox if true, unboxing conversions are assumed to be exactly typed (Integer to int only, not long or double)
182 * @return an adapter to the original handle with the desired new type,
183 * or the original target if the types are already identical
184 * or null if the adaptation cannot be made
185 */
186 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
187 boolean strict, boolean monobox) {
188 MethodType dstType = target.type();
189 if (srcType == dstType)
190 return target;
191 return makePairwiseConvertByEditor(target, srcType, strict, monobox);
192 }
193
194 private static int countNonNull(Object[] array) {
195 int count = 0;
196 for (Object x : array) {
197 if (x != null) ++count;
198 }
199 return count;
200 }
201
202 static MethodHandle makePairwiseConvertByEditor(MethodHandle target, MethodType srcType,
203 boolean strict, boolean monobox) {
204 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
205 int convCount = countNonNull(convSpecs);
206 if (convCount == 0)
207 return target.viewAsType(srcType, strict);
208 MethodType basicSrcType = srcType.basicType();
209 MethodType midType = target.type().basicType();
210 BoundMethodHandle mh = target.rebind();
211 // FIXME: Reduce number of bindings when there is more than one Class conversion.
212 // FIXME: Reduce number of bindings when there are repeated conversions.
213 for (int i = 0; i < convSpecs.length-1; i++) {
214 Object convSpec = convSpecs[i];
215 if (convSpec == null) continue;
216 MethodHandle fn;
217 if (convSpec instanceof Class) {
218 fn = getConstantHandle(MH_cast).bindTo(convSpec);
219 } else {
220 fn = (MethodHandle) convSpec;
221 }
222 Class<?> newType = basicSrcType.parameterType(i);
223 if (--convCount == 0)
224 midType = srcType;
225 else
226 midType = midType.changeParameterType(i, newType);
227 LambdaForm form2 = mh.editor().filterArgumentForm(1+i, BasicType.basicType(newType));
228 mh = mh.copyWithExtendL(midType, form2, fn);
229 mh = mh.rebind();
230 }
231 Object convSpec = convSpecs[convSpecs.length-1];
232 if (convSpec != null) {
233 MethodHandle fn;
234 if (convSpec instanceof Class) {
235 if (convSpec == void.class)
236 fn = null;
237 else
238 fn = getConstantHandle(MH_cast).bindTo(convSpec);
239 } else {
240 fn = (MethodHandle) convSpec;
241 }
242 Class<?> newType = basicSrcType.returnType();
243 assert(--convCount == 0);
244 midType = srcType;
245 if (fn != null) {
246 mh = mh.rebind(); // rebind if too complex
247 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), false);
248 mh = mh.copyWithExtendL(midType, form2, fn);
249 } else {
250 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), true);
251 mh = mh.copyWith(midType, form2);
252 }
253 }
254 assert(convCount == 0);
255 assert(mh.type().equals(srcType));
256 return mh;
257 }
258
259 static MethodHandle makePairwiseConvertIndirect(MethodHandle target, MethodType srcType,
260 boolean strict, boolean monobox) {
261 assert(target.type().parameterCount() == srcType.parameterCount());
262 // Calculate extra arguments (temporaries) required in the names array.
263 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
264 final int INARG_COUNT = srcType.parameterCount();
265 int convCount = countNonNull(convSpecs);
266 boolean retConv = (convSpecs[INARG_COUNT] != null);
267 boolean retVoid = srcType.returnType() == void.class;
268 if (retConv && retVoid) {
269 convCount -= 1;
270 retConv = false;
271 }
272
273 final int IN_MH = 0;
274 final int INARG_BASE = 1;
275 final int INARG_LIMIT = INARG_BASE + INARG_COUNT;
276 final int NAME_LIMIT = INARG_LIMIT + convCount + 1;
277 final int RETURN_CONV = (!retConv ? -1 : NAME_LIMIT - 1);
278 final int OUT_CALL = (!retConv ? NAME_LIMIT : RETURN_CONV) - 1;
279 final int RESULT = (retVoid ? -1 : NAME_LIMIT - 1);
280
281 // Now build a LambdaForm.
282 MethodType lambdaType = srcType.basicType().invokerType();
283 Name[] names = arguments(NAME_LIMIT - INARG_LIMIT, lambdaType);
284
285 // Collect the arguments to the outgoing call, maybe with conversions:
286 final int OUTARG_BASE = 0; // target MH is Name.function, name Name.arguments[0]
287 Object[] outArgs = new Object[OUTARG_BASE + INARG_COUNT];
288
289 int nameCursor = INARG_LIMIT;
290 for (int i = 0; i < INARG_COUNT; i++) {
291 Object convSpec = convSpecs[i];
292 if (convSpec == null) {
293 // do nothing: difference is trivial
294 outArgs[OUTARG_BASE + i] = names[INARG_BASE + i];
295 continue;
296 }
297
298 Name conv;
299 if (convSpec instanceof Class) {
300 Class<?> convClass = (Class<?>) convSpec;
301 conv = new Name(getConstantHandle(MH_cast), convClass, names[INARG_BASE + i]);
302 } else {
303 MethodHandle fn = (MethodHandle) convSpec;
304 conv = new Name(fn, names[INARG_BASE + i]);
305 }
306 assert(names[nameCursor] == null);
307 names[nameCursor++] = conv;
308 assert(outArgs[OUTARG_BASE + i] == null);
309 outArgs[OUTARG_BASE + i] = conv;
310 }
311
312 // Build argument array for the call.
313 assert(nameCursor == OUT_CALL);
314 names[OUT_CALL] = new Name(target, outArgs);
315
316 Object convSpec = convSpecs[INARG_COUNT];
317 if (!retConv) {
318 assert(OUT_CALL == names.length-1);
319 } else {
320 Name conv;
321 if (convSpec == void.class) {
322 conv = new Name(LambdaForm.constantZero(BasicType.basicType(srcType.returnType())));
323 } else if (convSpec instanceof Class) {
324 Class<?> convClass = (Class<?>) convSpec;
325 conv = new Name(getConstantHandle(MH_cast), convClass, names[OUT_CALL]);
326 } else {
327 MethodHandle fn = (MethodHandle) convSpec;
328 if (fn.type().parameterCount() == 0)
329 conv = new Name(fn); // don't pass retval to void conversion
330 else
331 conv = new Name(fn, names[OUT_CALL]);
332 }
333 assert(names[RETURN_CONV] == null);
334 names[RETURN_CONV] = conv;
335 assert(RETURN_CONV == names.length-1);
336 }
337
338 LambdaForm form = new LambdaForm("convert", lambdaType.parameterCount(), names, RESULT);
339 return SimpleMethodHandle.make(srcType, form);
340 }
341
342 static Object[] computeValueConversions(MethodType srcType, MethodType dstType,
343 boolean strict, boolean monobox) {
344 final int INARG_COUNT = srcType.parameterCount();
345 Object[] convSpecs = new Object[INARG_COUNT+1];
346 for (int i = 0; i <= INARG_COUNT; i++) {
347 boolean isRet = (i == INARG_COUNT);
348 Class<?> src = isRet ? dstType.returnType() : srcType.parameterType(i);
349 Class<?> dst = isRet ? srcType.returnType() : dstType.parameterType(i);
350 if (!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)) {
351 convSpecs[i] = valueConversion(src, dst, strict, monobox);
352 }
353 }
354 return convSpecs;
355 }
356 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
357 boolean strict) {
358 return makePairwiseConvert(target, srcType, strict, /*monobox=*/ false);
359 }
360
361 /**
362 * Find a conversion function from the given source to the given destination.
363 * This conversion function will be used as a LF NamedFunction.
364 * Return a Class object if a simple cast is needed.
365 * Return void.class if void is involved.
366 */
367 static Object valueConversion(Class<?> src, Class<?> dst, boolean strict, boolean monobox) {
368 assert(!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)); // caller responsibility
369 if (dst == void.class)
370 return dst;
371 MethodHandle fn;
372 if (src.isPrimitive()) {
373 if (src == void.class) {
374 return void.class; // caller must recognize this specially
375 } else if (dst.isPrimitive()) {
376 // Examples: int->byte, byte->int, boolean->int (!strict)
377 fn = ValueConversions.convertPrimitive(src, dst);
378 } else {
379 // Examples: int->Integer, boolean->Object, float->Number
380 Wrapper wsrc = Wrapper.forPrimitiveType(src);
381 fn = ValueConversions.boxExact(wsrc);
382 assert(fn.type().parameterType(0) == wsrc.primitiveType());
383 assert(fn.type().returnType() == wsrc.wrapperType());
384 if (!VerifyType.isNullConversion(wsrc.wrapperType(), dst, strict)) {
385 // Corner case, such as int->Long, which will probably fail.
386 MethodType mt = MethodType.methodType(dst, src);
387 if (strict)
388 fn = fn.asType(mt);
389 else
390 fn = MethodHandleImpl.makePairwiseConvert(fn, mt, /*strict=*/ false);
391 }
392 }
393 } else if (dst.isPrimitive()) {
394 Wrapper wdst = Wrapper.forPrimitiveType(dst);
395 if (monobox || src == wdst.wrapperType()) {
396 // Use a strongly-typed unboxer, if possible.
397 fn = ValueConversions.unboxExact(wdst, strict);
398 } else {
399 // Examples: Object->int, Number->int, Comparable->int, Byte->int
400 // must include additional conversions
401 // src must be examined at runtime, to detect Byte, Character, etc.
402 fn = (strict
403 ? ValueConversions.unboxWiden(wdst)
404 : ValueConversions.unboxCast(wdst));
405 }
406 } else {
407 // Simple reference conversion.
408 // Note: Do not check for a class hierarchy relation
409 // between src and dst. In all cases a 'null' argument
410 // will pass the cast conversion.
411 return dst;
412 }
413 assert(fn.type().parameterCount() <= 1) : "pc"+Arrays.asList(src.getSimpleName(), dst.getSimpleName(), fn);
414 return fn;
415 }
416
417 static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
418 MethodType type = target.type();
419 int last = type.parameterCount() - 1;
420 if (type.parameterType(last) != arrayType)
421 target = target.asType(type.changeParameterType(last, arrayType));
422 target = target.asFixedArity(); // make sure this attribute is turned off
423 return new AsVarargsCollector(target, arrayType);
424 }
425
426 private static final class AsVarargsCollector extends DelegatingMethodHandle {
427 private final MethodHandle target;
428 private final Class<?> arrayType;
429 private @Stable MethodHandle asCollectorCache;
430
431 AsVarargsCollector(MethodHandle target, Class<?> arrayType) {
432 this(target.type(), target, arrayType);
433 }
434 AsVarargsCollector(MethodType type, MethodHandle target, Class<?> arrayType) {
435 super(type, target);
436 this.target = target;
437 this.arrayType = arrayType;
438 this.asCollectorCache = target.asCollector(arrayType, 0);
439 }
440
441 @Override
442 public boolean isVarargsCollector() {
443 return true;
444 }
445
446 @Override
447 protected MethodHandle getTarget() {
448 return target;
449 }
450
451 @Override
452 public MethodHandle asFixedArity() {
453 return target;
454 }
455
456 @Override
457 MethodHandle setVarargs(MemberName member) {
458 if (member.isVarargs()) return this;
459 return asFixedArity();
460 }
461
462 @Override
463 public MethodHandle asTypeUncached(MethodType newType) {
464 MethodType type = this.type();
465 int collectArg = type.parameterCount() - 1;
466 int newArity = newType.parameterCount();
467 if (newArity == collectArg+1 &&
468 type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
469 // if arity and trailing parameter are compatible, do normal thing
470 return asTypeCache = asFixedArity().asType(newType);
471 }
472 // check cache
473 MethodHandle acc = asCollectorCache;
474 if (acc != null && acc.type().parameterCount() == newArity)
475 return asTypeCache = acc.asType(newType);
476 // build and cache a collector
477 int arrayLength = newArity - collectArg;
478 MethodHandle collector;
479 try {
480 collector = asFixedArity().asCollector(arrayType, arrayLength);
481 assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
482 } catch (IllegalArgumentException ex) {
483 throw new WrongMethodTypeException("cannot build collector", ex);
484 }
485 asCollectorCache = collector;
486 return asTypeCache = collector.asType(newType);
487 }
488
489 @Override
490 boolean viewAsTypeChecks(MethodType newType, boolean strict) {
491 super.viewAsTypeChecks(newType, true);
492 if (strict) return true;
493 // extra assertion for non-strict checks:
494 assert (type().lastParameterType().getComponentType()
495 .isAssignableFrom(
496 newType.lastParameterType().getComponentType()))
497 : Arrays.asList(this, newType);
498 return true;
499 }
500 }
501
502 /** Factory method: Spread selected argument. */
503 static MethodHandle makeSpreadArguments(MethodHandle target,
504 Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
505 MethodType targetType = target.type();
506
507 for (int i = 0; i < spreadArgCount; i++) {
508 Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i);
509 if (arg == null) arg = Object.class;
510 targetType = targetType.changeParameterType(spreadArgPos + i, arg);
511 }
512 target = target.asType(targetType);
513
514 MethodType srcType = targetType
515 .replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType);
516 // Now build a LambdaForm.
517 MethodType lambdaType = srcType.invokerType();
518 Name[] names = arguments(spreadArgCount + 2, lambdaType);
519 int nameCursor = lambdaType.parameterCount();
520 int[] indexes = new int[targetType.parameterCount()];
521
522 for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) {
523 Class<?> src = lambdaType.parameterType(i);
524 if (i == spreadArgPos) {
525 // Spread the array.
526 MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType);
527 Name array = names[argIndex];
528 names[nameCursor++] = new Name(NF_checkSpreadArgument, array, spreadArgCount);
529 for (int j = 0; j < spreadArgCount; i++, j++) {
530 indexes[i] = nameCursor;
531 names[nameCursor++] = new Name(aload, array, j);
532 }
533 } else if (i < indexes.length) {
534 indexes[i] = argIndex;
535 }
536 }
537 assert(nameCursor == names.length-1); // leave room for the final call
538
539 // Build argument array for the call.
540 Name[] targetArgs = new Name[targetType.parameterCount()];
541 for (int i = 0; i < targetType.parameterCount(); i++) {
542 int idx = indexes[i];
543 targetArgs[i] = names[idx];
544 }
545 names[names.length - 1] = new Name(target, (Object[]) targetArgs);
546
547 LambdaForm form = new LambdaForm("spread", lambdaType.parameterCount(), names);
548 return SimpleMethodHandle.make(srcType, form);
549 }
550
551 static void checkSpreadArgument(Object av, int n) {
552 if (av == null) {
553 if (n == 0) return;
554 } else if (av instanceof Object[]) {
555 int len = ((Object[])av).length;
556 if (len == n) return;
557 } else {
558 int len = java.lang.reflect.Array.getLength(av);
559 if (len == n) return;
560 }
561 // fall through to error:
562 throw newIllegalArgumentException("array is not of length "+n);
563 }
564
565 /** Factory method: Collect or filter selected argument(s). */
566 static MethodHandle makeCollectArguments(MethodHandle target,
567 MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) {
568 MethodType targetType = target.type(); // (a..., c, [b...])=>r
569 MethodType collectorType = collector.type(); // (b...)=>c
570 int collectArgCount = collectorType.parameterCount();
571 Class<?> collectValType = collectorType.returnType();
572 int collectValCount = (collectValType == void.class ? 0 : 1);
573 MethodType srcType = targetType // (a..., [b...])=>r
574 .dropParameterTypes(collectArgPos, collectArgPos+collectValCount);
575 if (!retainOriginalArgs) { // (a..., b...)=>r
576 srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterList());
577 }
578 // in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ]
579 // out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ]
580 // out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ]
581
582 // Now build a LambdaForm.
583 MethodType lambdaType = srcType.invokerType();
584 Name[] names = arguments(2, lambdaType);
585 final int collectNamePos = names.length - 2;
586 final int targetNamePos = names.length - 1;
587
588 Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount);
589 names[collectNamePos] = new Name(collector, (Object[]) collectorArgs);
590
591 // Build argument array for the target.
592 // Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ].
593 // Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ].
594 Name[] targetArgs = new Name[targetType.parameterCount()];
595 int inputArgPos = 1; // incoming LF args to copy to target
596 int targetArgPos = 0; // fill pointer for targetArgs
597 int chunk = collectArgPos; // |headArgs|
598 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
599 inputArgPos += chunk;
600 targetArgPos += chunk;
601 if (collectValType != void.class) {
602 targetArgs[targetArgPos++] = names[collectNamePos];
603 }
604 chunk = collectArgCount;
605 if (retainOriginalArgs) {
606 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
607 targetArgPos += chunk; // optionally pass on the collected chunk
608 }
609 inputArgPos += chunk;
610 chunk = targetArgs.length - targetArgPos; // all the rest
611 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
612 assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also
613 names[targetNamePos] = new Name(target, (Object[]) targetArgs);
614
615 LambdaForm form = new LambdaForm("collect", lambdaType.parameterCount(), names);
616 return SimpleMethodHandle.make(srcType, form);
617 }
618
619 @LambdaForm.Hidden
620 static
621 MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
622 if (testResult) {
623 return target;
624 } else {
625 return fallback;
626 }
627 }
628
629 // Intrinsified by C2. Counters are used during parsing to calculate branch frequencies.
630 @LambdaForm.Hidden
631 @jdk.internal.HotSpotIntrinsicCandidate
632 static
633 boolean profileBoolean(boolean result, int[] counters) {
634 // Profile is int[2] where [0] and [1] correspond to false and true occurrences respectively.
635 int idx = result ? 1 : 0;
636 try {
637 counters[idx] = Math.addExact(counters[idx], 1);
638 } catch (ArithmeticException e) {
639 // Avoid continuous overflow by halving the problematic count.
640 counters[idx] = counters[idx] / 2;
641 }
642 return result;
643 }
644
645 // Intrinsified by C2. Returns true if obj is a compile-time constant.
646 @LambdaForm.Hidden
647 @jdk.internal.HotSpotIntrinsicCandidate
648 static
649 boolean isCompileConstant(Object obj) {
650 return false;
651 }
652
653 static
654 MethodHandle makeGuardWithTest(MethodHandle test,
655 MethodHandle target,
656 MethodHandle fallback) {
657 MethodType type = target.type();
658 assert(test.type().equals(type.changeReturnType(boolean.class)) && fallback.type().equals(type));
659 MethodType basicType = type.basicType();
660 LambdaForm form = makeGuardWithTestForm(basicType);
661 BoundMethodHandle mh;
662 try {
663 if (PROFILE_GWT) {
664 int[] counts = new int[2];
665 mh = (BoundMethodHandle)
666 BoundMethodHandle.speciesData_LLLL().constructor().invokeBasic(type, form,
667 (Object) test, (Object) profile(target), (Object) profile(fallback), counts);
668 } else {
669 mh = (BoundMethodHandle)
670 BoundMethodHandle.speciesData_LLL().constructor().invokeBasic(type, form,
671 (Object) test, (Object) profile(target), (Object) profile(fallback));
672 }
673 } catch (Throwable ex) {
674 throw uncaughtException(ex);
675 }
676 assert(mh.type() == type);
677 return mh;
678 }
679
680
681 static
682 MethodHandle profile(MethodHandle target) {
683 if (DONT_INLINE_THRESHOLD >= 0) {
684 return makeBlockInliningWrapper(target);
685 } else {
686 return target;
687 }
688 }
689
690 /**
691 * Block inlining during JIT-compilation of a target method handle if it hasn't been invoked enough times.
692 * Corresponding LambdaForm has @DontInline when compiled into bytecode.
693 */
694 static
695 MethodHandle makeBlockInliningWrapper(MethodHandle target) {
696 LambdaForm lform;
697 if (DONT_INLINE_THRESHOLD > 0) {
698 lform = Makers.PRODUCE_BLOCK_INLINING_FORM.apply(target);
699 } else {
700 lform = Makers.PRODUCE_REINVOKER_FORM.apply(target);
701 }
702 return new CountingWrapper(target, lform,
703 Makers.PRODUCE_BLOCK_INLINING_FORM, Makers.PRODUCE_REINVOKER_FORM,
704 DONT_INLINE_THRESHOLD);
705 }
706
707 private final static class Makers {
708 /** Constructs reinvoker lambda form which block inlining during JIT-compilation for a particular method handle */
709 static final Function<MethodHandle, LambdaForm> PRODUCE_BLOCK_INLINING_FORM = new Function<MethodHandle, LambdaForm>() {
710 @Override
711 public LambdaForm apply(MethodHandle target) {
712 return DelegatingMethodHandle.makeReinvokerForm(target,
713 MethodTypeForm.LF_DELEGATE_BLOCK_INLINING, CountingWrapper.class, "reinvoker.dontInline", false,
714 DelegatingMethodHandle.NF_getTarget, CountingWrapper.NF_maybeStopCounting);
715 }
716 };
717
718 /** Constructs simple reinvoker lambda form for a particular method handle */
719 static final Function<MethodHandle, LambdaForm> PRODUCE_REINVOKER_FORM = new Function<MethodHandle, LambdaForm>() {
720 @Override
721 public LambdaForm apply(MethodHandle target) {
722 return DelegatingMethodHandle.makeReinvokerForm(target,
723 MethodTypeForm.LF_DELEGATE, DelegatingMethodHandle.class, DelegatingMethodHandle.NF_getTarget);
724 }
725 };
726
727 /** Maker of type-polymorphic varargs */
728 static final ClassValue<MethodHandle[]> TYPED_COLLECTORS = new ClassValue<MethodHandle[]>() {
729 @Override
730 protected MethodHandle[] computeValue(Class<?> type) {
731 return new MethodHandle[MAX_JVM_ARITY + 1];
732 }
733 };
734 }
735
736 /**
737 * Counting method handle. It has 2 states: counting and non-counting.
738 * It is in counting state for the first n invocations and then transitions to non-counting state.
739 * Behavior in counting and non-counting states is determined by lambda forms produced by
740 * countingFormProducer & nonCountingFormProducer respectively.
741 */
742 static class CountingWrapper extends DelegatingMethodHandle {
743 private final MethodHandle target;
744 private int count;
745 private Function<MethodHandle, LambdaForm> countingFormProducer;
746 private Function<MethodHandle, LambdaForm> nonCountingFormProducer;
747 private volatile boolean isCounting;
748
749 private CountingWrapper(MethodHandle target, LambdaForm lform,
750 Function<MethodHandle, LambdaForm> countingFromProducer,
751 Function<MethodHandle, LambdaForm> nonCountingFormProducer,
752 int count) {
753 super(target.type(), lform);
754 this.target = target;
755 this.count = count;
756 this.countingFormProducer = countingFromProducer;
757 this.nonCountingFormProducer = nonCountingFormProducer;
758 this.isCounting = (count > 0);
759 }
760
761 @Hidden
762 @Override
763 protected MethodHandle getTarget() {
764 return target;
765 }
766
767 @Override
768 public MethodHandle asTypeUncached(MethodType newType) {
769 MethodHandle newTarget = target.asType(newType);
770 MethodHandle wrapper;
771 if (isCounting) {
772 LambdaForm lform;
773 lform = countingFormProducer.apply(newTarget);
774 wrapper = new CountingWrapper(newTarget, lform, countingFormProducer, nonCountingFormProducer, DONT_INLINE_THRESHOLD);
775 } else {
776 wrapper = newTarget; // no need for a counting wrapper anymore
777 }
778 return (asTypeCache = wrapper);
779 }
780
781 // Customize target if counting happens for too long.
782 private int invocations = CUSTOMIZE_THRESHOLD;
783 private void maybeCustomizeTarget() {
784 int c = invocations;
785 if (c >= 0) {
786 if (c == 1) {
787 target.customize();
788 }
789 invocations = c - 1;
790 }
791 }
792
793 boolean countDown() {
794 int c = count;
795 maybeCustomizeTarget();
796 if (c <= 1) {
797 // Try to limit number of updates. MethodHandle.updateForm() doesn't guarantee LF update visibility.
798 if (isCounting) {
799 isCounting = false;
800 return true;
801 } else {
802 return false;
803 }
804 } else {
805 count = c - 1;
806 return false;
807 }
808 }
809
810 @Hidden
811 static void maybeStopCounting(Object o1) {
812 CountingWrapper wrapper = (CountingWrapper) o1;
813 if (wrapper.countDown()) {
814 // Reached invocation threshold. Replace counting behavior with a non-counting one.
815 LambdaForm lform = wrapper.nonCountingFormProducer.apply(wrapper.target);
816 lform.compileToBytecode(); // speed up warmup by avoiding LF interpretation again after transition
817 wrapper.updateForm(lform);
818 }
819 }
820
821 static final NamedFunction NF_maybeStopCounting;
822 static {
823 Class<?> THIS_CLASS = CountingWrapper.class;
824 try {
825 NF_maybeStopCounting = new NamedFunction(THIS_CLASS.getDeclaredMethod("maybeStopCounting", Object.class));
826 } catch (ReflectiveOperationException ex) {
827 throw newInternalError(ex);
828 }
829 }
830 }
831
832 static
833 LambdaForm makeGuardWithTestForm(MethodType basicType) {
834 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWT);
835 if (lform != null) return lform;
836 final int THIS_MH = 0; // the BMH_LLL
837 final int ARG_BASE = 1; // start of incoming arguments
838 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
839 int nameCursor = ARG_LIMIT;
840 final int GET_TEST = nameCursor++;
841 final int GET_TARGET = nameCursor++;
842 final int GET_FALLBACK = nameCursor++;
843 final int GET_COUNTERS = PROFILE_GWT ? nameCursor++ : -1;
844 final int CALL_TEST = nameCursor++;
845 final int PROFILE = (GET_COUNTERS != -1) ? nameCursor++ : -1;
846 final int TEST = nameCursor-1; // previous statement: either PROFILE or CALL_TEST
847 final int SELECT_ALT = nameCursor++;
848 final int CALL_TARGET = nameCursor++;
849 assert(CALL_TARGET == SELECT_ALT+1); // must be true to trigger IBG.emitSelectAlternative
850
851 MethodType lambdaType = basicType.invokerType();
852 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
853
854 BoundMethodHandle.SpeciesData data =
855 (GET_COUNTERS != -1) ? BoundMethodHandle.speciesData_LLLL()
856 : BoundMethodHandle.speciesData_LLL();
857 names[THIS_MH] = names[THIS_MH].withConstraint(data);
858 names[GET_TEST] = new Name(data.getterFunction(0), names[THIS_MH]);
859 names[GET_TARGET] = new Name(data.getterFunction(1), names[THIS_MH]);
860 names[GET_FALLBACK] = new Name(data.getterFunction(2), names[THIS_MH]);
861 if (GET_COUNTERS != -1) {
862 names[GET_COUNTERS] = new Name(data.getterFunction(3), names[THIS_MH]);
863 }
864 Object[] invokeArgs = Arrays.copyOfRange(names, 0, ARG_LIMIT, Object[].class);
865
866 // call test
867 MethodType testType = basicType.changeReturnType(boolean.class).basicType();
868 invokeArgs[0] = names[GET_TEST];
869 names[CALL_TEST] = new Name(testType, invokeArgs);
870
871 // profile branch
872 if (PROFILE != -1) {
873 names[PROFILE] = new Name(NF_profileBoolean, names[CALL_TEST], names[GET_COUNTERS]);
874 }
875 // call selectAlternative
876 names[SELECT_ALT] = new Name(getConstantHandle(MH_selectAlternative), names[TEST], names[GET_TARGET], names[GET_FALLBACK]);
877
878 // call target or fallback
879 invokeArgs[0] = names[SELECT_ALT];
880 names[CALL_TARGET] = new Name(basicType, invokeArgs);
881
882 lform = new LambdaForm("guard", lambdaType.parameterCount(), names, /*forceInline=*/true);
883
884 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWT, lform);
885 }
886
887 /**
888 * The LambdaForm shape for catchException combinator is the following:
889 * <blockquote><pre>{@code
890 * guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{
891 * t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L);
892 * t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L);
893 * t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L);
894 * t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L);
895 * t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L);
896 * t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L);
897 * t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L);
898 * t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I}
899 * }</pre></blockquote>
900 *
901 * argL0 and argL2 are target and catcher method handles. argL1 is exception class.
902 * argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[]
903 * (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()).
904 *
905 * Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms
906 * among catchException combinators with the same basic type.
907 */
908 private static LambdaForm makeGuardWithCatchForm(MethodType basicType) {
909 MethodType lambdaType = basicType.invokerType();
910
911 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC);
912 if (lform != null) {
913 return lform;
914 }
915 final int THIS_MH = 0; // the BMH_LLLLL
916 final int ARG_BASE = 1; // start of incoming arguments
917 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
918
919 int nameCursor = ARG_LIMIT;
920 final int GET_TARGET = nameCursor++;
921 final int GET_CLASS = nameCursor++;
922 final int GET_CATCHER = nameCursor++;
923 final int GET_COLLECT_ARGS = nameCursor++;
924 final int GET_UNBOX_RESULT = nameCursor++;
925 final int BOXED_ARGS = nameCursor++;
926 final int TRY_CATCH = nameCursor++;
927 final int UNBOX_RESULT = nameCursor++;
928
929 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
930
931 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
932 names[THIS_MH] = names[THIS_MH].withConstraint(data);
933 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
934 names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]);
935 names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]);
936 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]);
937 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]);
938
939 // FIXME: rework argument boxing/result unboxing logic for LF interpretation
940
941 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
942 MethodType collectArgsType = basicType.changeReturnType(Object.class);
943 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
944 Object[] args = new Object[invokeBasic.type().parameterCount()];
945 args[0] = names[GET_COLLECT_ARGS];
946 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
947 names[BOXED_ARGS] = new Name(makeIntrinsic(invokeBasic, Intrinsic.GUARD_WITH_CATCH), args);
948
949 // t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L);
950 Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]};
951 names[TRY_CATCH] = new Name(NF_guardWithCatch, gwcArgs);
952
953 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
954 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
955 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]};
956 names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
957
958 lform = new LambdaForm("guardWithCatch", lambdaType.parameterCount(), names);
959
960 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform);
961 }
962
963 static
964 MethodHandle makeGuardWithCatch(MethodHandle target,
965 Class<? extends Throwable> exType,
966 MethodHandle catcher) {
967 MethodType type = target.type();
968 LambdaForm form = makeGuardWithCatchForm(type.basicType());
969
970 // Prepare auxiliary method handles used during LambdaForm interpretation.
971 // Box arguments and wrap them into Object[]: ValueConversions.array().
972 MethodType varargsType = type.changeReturnType(Object[].class);
973 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
974 // Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore().
975 MethodHandle unboxResult;
976 Class<?> rtype = type.returnType();
977 if (rtype.isPrimitive()) {
978 if (rtype == void.class) {
979 unboxResult = ValueConversions.ignore();
980 } else {
981 Wrapper w = Wrapper.forPrimitiveType(type.returnType());
982 unboxResult = ValueConversions.unboxExact(w);
983 }
984 } else {
985 unboxResult = MethodHandles.identity(Object.class);
986 }
987
988 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
989 BoundMethodHandle mh;
990 try {
991 mh = (BoundMethodHandle)
992 data.constructor().invokeBasic(type, form, (Object) target, (Object) exType, (Object) catcher,
993 (Object) collectArgs, (Object) unboxResult);
994 } catch (Throwable ex) {
995 throw uncaughtException(ex);
996 }
997 assert(mh.type() == type);
998 return mh;
999 }
1000
1001 /**
1002 * Intrinsified during LambdaForm compilation
1003 * (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}).
1004 */
1005 @LambdaForm.Hidden
1006 static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher,
1007 Object... av) throws Throwable {
1008 // Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case.
1009 try {
1010 return target.asFixedArity().invokeWithArguments(av);
1011 } catch (Throwable t) {
1012 if (!exType.isInstance(t)) throw t;
1013 return catcher.asFixedArity().invokeWithArguments(prepend(t, av));
1014 }
1015 }
1016
1017 /** Prepend an element {@code elem} to an {@code array}. */
1018 @LambdaForm.Hidden
1019 private static Object[] prepend(Object elem, Object[] array) {
1020 Object[] newArray = new Object[array.length+1];
1021 newArray[0] = elem;
1022 System.arraycopy(array, 0, newArray, 1, array.length);
1023 return newArray;
1024 }
1025
1026 static
1027 MethodHandle throwException(MethodType type) {
1028 assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
1029 int arity = type.parameterCount();
1030 if (arity > 1) {
1031 MethodHandle mh = throwException(type.dropParameterTypes(1, arity));
1032 mh = MethodHandles.dropArguments(mh, 1, type.parameterList().subList(1, arity));
1033 return mh;
1034 }
1035 return makePairwiseConvert(NF_throwException.resolvedHandle(), type, false, true);
1036 }
1037
1038 static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
1039
1040 static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
1041 static MethodHandle fakeMethodHandleInvoke(MemberName method) {
1042 int idx;
1043 assert(method.isMethodHandleInvoke());
1044 switch (method.getName()) {
1045 case "invoke": idx = 0; break;
1046 case "invokeExact": idx = 1; break;
1047 default: throw new InternalError(method.getName());
1048 }
1049 MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
1050 if (mh != null) return mh;
1051 MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
1052 MethodHandle.class, Object[].class);
1053 mh = throwException(type);
1054 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
1055 if (!method.getInvocationType().equals(mh.type()))
1056 throw new InternalError(method.toString());
1057 mh = mh.withInternalMemberName(method, false);
1058 mh = mh.withVarargs(true);
1059 assert(method.isVarargs());
1060 FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
1061 return mh;
1062 }
1063 static MethodHandle fakeVarHandleInvoke(MemberName method) {
1064 // TODO caching, is it necessary?
1065 MethodType type = MethodType.methodType(method.getReturnType(), UnsupportedOperationException.class,
1066 VarHandle.class, Object[].class);
1067 MethodHandle mh = throwException(type);
1068 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke VarHandle"));
1069 if (!method.getInvocationType().equals(mh.type()))
1070 throw new InternalError(method.toString());
1071 mh = mh.withInternalMemberName(method, false);
1072 mh = mh.asVarargsCollector(Object[].class);
1073 assert(method.isVarargs());
1074 return mh;
1075 }
1076
1077 /**
1078 * Create an alias for the method handle which, when called,
1079 * appears to be called from the same class loader and protection domain
1080 * as hostClass.
1081 * This is an expensive no-op unless the method which is called
1082 * is sensitive to its caller. A small number of system methods
1083 * are in this category, including Class.forName and Method.invoke.
1084 */
1085 static
1086 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1087 return BindCaller.bindCaller(mh, hostClass);
1088 }
1089
1090 // Put the whole mess into its own nested class.
1091 // That way we can lazily load the code and set up the constants.
1092 private static class BindCaller {
1093 static
1094 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1095 // Do not use this function to inject calls into system classes.
1096 if (hostClass == null
1097 || (hostClass.isArray() ||
1098 hostClass.isPrimitive() ||
1099 hostClass.getName().startsWith("java.") ||
1100 hostClass.getName().startsWith("sun."))) {
1101 throw new InternalError(); // does not happen, and should not anyway
1102 }
1103 // For simplicity, convert mh to a varargs-like method.
1104 MethodHandle vamh = prepareForInvoker(mh);
1105 // Cache the result of makeInjectedInvoker once per argument class.
1106 MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
1107 return restoreToType(bccInvoker.bindTo(vamh), mh, hostClass);
1108 }
1109
1110 private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
1111 Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null);
1112 if (hostClass.getClassLoader() != bcc.getClassLoader())
1113 throw new InternalError(hostClass.getName()+" (CL)");
1114 try {
1115 if (hostClass.getProtectionDomain() != bcc.getProtectionDomain())
1116 throw new InternalError(hostClass.getName()+" (PD)");
1117 } catch (SecurityException ex) {
1118 // Self-check was blocked by security manager. This is OK.
1119 // In fact the whole try body could be turned into an assertion.
1120 }
1121 try {
1122 MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class));
1123 init.invokeExact(); // force initialization of the class
1124 } catch (Throwable ex) {
1125 throw uncaughtException(ex);
1126 }
1127 MethodHandle bccInvoker;
1128 try {
1129 MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1130 bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT);
1131 } catch (ReflectiveOperationException ex) {
1132 throw uncaughtException(ex);
1133 }
1134 // Test the invoker, to ensure that it really injects into the right place.
1135 try {
1136 MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
1137 Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc});
1138 } catch (Throwable ex) {
1139 throw new InternalError(ex);
1140 }
1141 return bccInvoker;
1142 }
1143 private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() {
1144 @Override protected MethodHandle computeValue(Class<?> hostClass) {
1145 return makeInjectedInvoker(hostClass);
1146 }
1147 };
1148
1149 // Adapt mh so that it can be called directly from an injected invoker:
1150 private static MethodHandle prepareForInvoker(MethodHandle mh) {
1151 mh = mh.asFixedArity();
1152 MethodType mt = mh.type();
1153 int arity = mt.parameterCount();
1154 MethodHandle vamh = mh.asType(mt.generic());
1155 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1156 vamh = vamh.asSpreader(Object[].class, arity);
1157 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1158 return vamh;
1159 }
1160
1161 // Undo the adapter effect of prepareForInvoker:
1162 private static MethodHandle restoreToType(MethodHandle vamh,
1163 MethodHandle original,
1164 Class<?> hostClass) {
1165 MethodType type = original.type();
1166 MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount());
1167 MemberName member = original.internalMemberName();
1168 mh = mh.asType(type);
1169 mh = new WrappedMember(mh, type, member, original.isInvokeSpecial(), hostClass);
1170 return mh;
1171 }
1172
1173 private static final MethodHandle MH_checkCallerClass;
1174 static {
1175 final Class<?> THIS_CLASS = BindCaller.class;
1176 assert(checkCallerClass(THIS_CLASS, THIS_CLASS));
1177 try {
1178 MH_checkCallerClass = IMPL_LOOKUP
1179 .findStatic(THIS_CLASS, "checkCallerClass",
1180 MethodType.methodType(boolean.class, Class.class, Class.class));
1181 assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS, THIS_CLASS));
1182 } catch (Throwable ex) {
1183 throw new InternalError(ex);
1184 }
1185 }
1186
1187 @CallerSensitive
1188 private static boolean checkCallerClass(Class<?> expected, Class<?> expected2) {
1189 // This method is called via MH_checkCallerClass and so it's
1190 // correct to ask for the immediate caller here.
1191 Class<?> actual = Reflection.getCallerClass();
1192 if (actual != expected && actual != expected2)
1193 throw new InternalError("found "+actual.getName()+", expected "+expected.getName()
1194 +(expected == expected2 ? "" : ", or else "+expected2.getName()));
1195 return true;
1196 }
1197
1198 private static final byte[] T_BYTES;
1199 static {
1200 final Object[] values = {null};
1201 AccessController.doPrivileged(new PrivilegedAction<>() {
1202 public Void run() {
1203 try {
1204 Class<T> tClass = T.class;
1205 String tName = tClass.getName();
1206 String tResource = tName.substring(tName.lastIndexOf('.')+1)+".class";
1207 try (java.io.InputStream in = tClass.getResourceAsStream(tResource)) {
1208 values[0] = in.readAllBytes();
1209 }
1210 } catch (java.io.IOException ex) {
1211 throw new InternalError(ex);
1212 }
1213 return null;
1214 }
1215 });
1216 T_BYTES = (byte[]) values[0];
1217 }
1218
1219 // The following class is used as a template for Unsafe.defineAnonymousClass:
1220 private static class T {
1221 static void init() { } // side effect: initializes this class
1222 static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
1223 return vamh.invokeExact(args);
1224 }
1225 }
1226 }
1227
1228
1229 /** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */
1230 private static final class WrappedMember extends DelegatingMethodHandle {
1231 private final MethodHandle target;
1232 private final MemberName member;
1233 private final Class<?> callerClass;
1234 private final boolean isInvokeSpecial;
1235
1236 private WrappedMember(MethodHandle target, MethodType type,
1237 MemberName member, boolean isInvokeSpecial,
1238 Class<?> callerClass) {
1239 super(type, target);
1240 this.target = target;
1241 this.member = member;
1242 this.callerClass = callerClass;
1243 this.isInvokeSpecial = isInvokeSpecial;
1244 }
1245
1246 @Override
1247 MemberName internalMemberName() {
1248 return member;
1249 }
1250 @Override
1251 Class<?> internalCallerClass() {
1252 return callerClass;
1253 }
1254 @Override
1255 boolean isInvokeSpecial() {
1256 return isInvokeSpecial;
1257 }
1258 @Override
1259 protected MethodHandle getTarget() {
1260 return target;
1261 }
1262 @Override
1263 public MethodHandle asTypeUncached(MethodType newType) {
1264 // This MH is an alias for target, except for the MemberName
1265 // Drop the MemberName if there is any conversion.
1266 return asTypeCache = target.asType(newType);
1267 }
1268 }
1269
1270 static MethodHandle makeWrappedMember(MethodHandle target, MemberName member, boolean isInvokeSpecial) {
1271 if (member.equals(target.internalMemberName()) && isInvokeSpecial == target.isInvokeSpecial())
1272 return target;
1273 return new WrappedMember(target, target.type(), member, isInvokeSpecial, null);
1274 }
1275
1276 /** Intrinsic IDs */
1277 /*non-public*/
1278 enum Intrinsic {
1279 SELECT_ALTERNATIVE,
1280 GUARD_WITH_CATCH,
1281 NEW_ARRAY,
1282 ARRAY_LOAD,
1283 ARRAY_STORE,
1284 IDENTITY,
1285 ZERO,
1286 NONE // no intrinsic associated
1287 }
1288
1289 /** Mark arbitrary method handle as intrinsic.
1290 * InvokerBytecodeGenerator uses this info to produce more efficient bytecode shape. */
1291 private static final class IntrinsicMethodHandle extends DelegatingMethodHandle {
1292 private final MethodHandle target;
1293 private final Intrinsic intrinsicName;
1294
1295 IntrinsicMethodHandle(MethodHandle target, Intrinsic intrinsicName) {
1296 super(target.type(), target);
1297 this.target = target;
1298 this.intrinsicName = intrinsicName;
1299 }
1300
1301 @Override
1302 protected MethodHandle getTarget() {
1303 return target;
1304 }
1305
1306 @Override
1307 Intrinsic intrinsicName() {
1308 return intrinsicName;
1309 }
1310
1311 @Override
1312 public MethodHandle asTypeUncached(MethodType newType) {
1313 // This MH is an alias for target, except for the intrinsic name
1314 // Drop the name if there is any conversion.
1315 return asTypeCache = target.asType(newType);
1316 }
1317
1318 @Override
1319 String internalProperties() {
1320 return super.internalProperties() +
1321 "\n& Intrinsic="+intrinsicName;
1322 }
1323
1324 @Override
1325 public MethodHandle asCollector(Class<?> arrayType, int arrayLength) {
1326 if (intrinsicName == Intrinsic.IDENTITY) {
1327 MethodType resultType = type().asCollectorType(arrayType, type().parameterCount() - 1, arrayLength);
1328 MethodHandle newArray = MethodHandleImpl.varargsArray(arrayType, arrayLength);
1329 return newArray.asType(resultType);
1330 }
1331 return super.asCollector(arrayType, arrayLength);
1332 }
1333 }
1334
1335 static MethodHandle makeIntrinsic(MethodHandle target, Intrinsic intrinsicName) {
1336 if (intrinsicName == target.intrinsicName())
1337 return target;
1338 return new IntrinsicMethodHandle(target, intrinsicName);
1339 }
1340
1341 static MethodHandle makeIntrinsic(MethodType type, LambdaForm form, Intrinsic intrinsicName) {
1342 return new IntrinsicMethodHandle(SimpleMethodHandle.make(type, form), intrinsicName);
1343 }
1344
1345 /// Collection of multiple arguments.
1346
1347 private static MethodHandle findCollector(String name, int nargs, Class<?> rtype, Class<?>... ptypes) {
1348 MethodType type = MethodType.genericMethodType(nargs)
1349 .changeReturnType(rtype)
1350 .insertParameterTypes(0, ptypes);
1351 try {
1352 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, name, type);
1353 } catch (ReflectiveOperationException ex) {
1354 return null;
1355 }
1356 }
1357
1358 private static final Object[] NO_ARGS_ARRAY = {};
1359 private static Object[] makeArray(Object... args) { return args; }
1360 private static Object[] array() { return NO_ARGS_ARRAY; }
1361 private static Object[] array(Object a0)
1362 { return makeArray(a0); }
1363 private static Object[] array(Object a0, Object a1)
1364 { return makeArray(a0, a1); }
1365 private static Object[] array(Object a0, Object a1, Object a2)
1366 { return makeArray(a0, a1, a2); }
1367 private static Object[] array(Object a0, Object a1, Object a2, Object a3)
1368 { return makeArray(a0, a1, a2, a3); }
1369 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1370 Object a4)
1371 { return makeArray(a0, a1, a2, a3, a4); }
1372 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1373 Object a4, Object a5)
1374 { return makeArray(a0, a1, a2, a3, a4, a5); }
1375 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1376 Object a4, Object a5, Object a6)
1377 { return makeArray(a0, a1, a2, a3, a4, a5, a6); }
1378 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1379 Object a4, Object a5, Object a6, Object a7)
1380 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7); }
1381 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1382 Object a4, Object a5, Object a6, Object a7,
1383 Object a8)
1384 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8); }
1385 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1386 Object a4, Object a5, Object a6, Object a7,
1387 Object a8, Object a9)
1388 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
1389
1390 private static final int ARRAYS_COUNT = 11;
1391 private static final @Stable MethodHandle[] ARRAYS = new MethodHandle[MAX_ARITY + 1];
1392
1393 // filling versions of the above:
1394 // using Integer len instead of int len and no varargs to avoid bootstrapping problems
1395 private static Object[] fillNewArray(Integer len, Object[] /*not ...*/ args) {
1396 Object[] a = new Object[len];
1397 fillWithArguments(a, 0, args);
1398 return a;
1399 }
1400 private static Object[] fillNewTypedArray(Object[] example, Integer len, Object[] /*not ...*/ args) {
1401 Object[] a = Arrays.copyOf(example, len);
1402 assert(a.getClass() != Object[].class);
1403 fillWithArguments(a, 0, args);
1404 return a;
1405 }
1406 private static void fillWithArguments(Object[] a, int pos, Object... args) {
1407 System.arraycopy(args, 0, a, pos, args.length);
1408 }
1409 // using Integer pos instead of int pos to avoid bootstrapping problems
1410 private static Object[] fillArray(Integer pos, Object[] a, Object a0)
1411 { fillWithArguments(a, pos, a0); return a; }
1412 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1)
1413 { fillWithArguments(a, pos, a0, a1); return a; }
1414 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2)
1415 { fillWithArguments(a, pos, a0, a1, a2); return a; }
1416 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3)
1417 { fillWithArguments(a, pos, a0, a1, a2, a3); return a; }
1418 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1419 Object a4)
1420 { fillWithArguments(a, pos, a0, a1, a2, a3, a4); return a; }
1421 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1422 Object a4, Object a5)
1423 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5); return a; }
1424 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1425 Object a4, Object a5, Object a6)
1426 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6); return a; }
1427 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1428 Object a4, Object a5, Object a6, Object a7)
1429 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7); return a; }
1430 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1431 Object a4, Object a5, Object a6, Object a7,
1432 Object a8)
1433 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8); return a; }
1434 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1435 Object a4, Object a5, Object a6, Object a7,
1436 Object a8, Object a9)
1437 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); return a; }
1438
1439 private static final int FILL_ARRAYS_COUNT = 11; // current number of fillArray methods
1440 private static final @Stable MethodHandle[] FILL_ARRAYS = new MethodHandle[FILL_ARRAYS_COUNT];
1441
1442 private static MethodHandle getFillArray(int count) {
1443 assert (count > 0 && count < FILL_ARRAYS_COUNT);
1444 MethodHandle mh = FILL_ARRAYS[count];
1445 if (mh != null) {
1446 return mh;
1447 }
1448 mh = findCollector("fillArray", count, Object[].class, Integer.class, Object[].class);
1449 FILL_ARRAYS[count] = mh;
1450 return mh;
1451 }
1452
1453 private static Object copyAsPrimitiveArray(Wrapper w, Object... boxes) {
1454 Object a = w.makeArray(boxes.length);
1455 w.copyArrayUnboxing(boxes, 0, a, 0, boxes.length);
1456 return a;
1457 }
1458
1459 /** Return a method handle that takes the indicated number of Object
1460 * arguments and returns an Object array of them, as if for varargs.
1461 */
1462 static MethodHandle varargsArray(int nargs) {
1463 MethodHandle mh = ARRAYS[nargs];
1464 if (mh != null) {
1465 return mh;
1466 }
1467 if (nargs < ARRAYS_COUNT) {
1468 mh = findCollector("array", nargs, Object[].class);
1469 } else {
1470 mh = buildVarargsArray(getConstantHandle(MH_fillNewArray),
1471 getConstantHandle(MH_arrayIdentity), nargs);
1472 }
1473 assert(assertCorrectArity(mh, nargs));
1474 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1475 return ARRAYS[nargs] = mh;
1476 }
1477
1478 private static boolean assertCorrectArity(MethodHandle mh, int arity) {
1479 assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh;
1480 return true;
1481 }
1482
1483 // Array identity function (used as getConstantHandle(MH_arrayIdentity)).
1484 static <T> T[] identity(T[] x) {
1485 return x;
1486 }
1487
1488 private static MethodHandle buildVarargsArray(MethodHandle newArray, MethodHandle finisher, int nargs) {
1489 // Build up the result mh as a sequence of fills like this:
1490 // finisher(fill(fill(newArrayWA(23,x1..x10),10,x11..x20),20,x21..x23))
1491 // The various fill(_,10*I,___*[J]) are reusable.
1492 int leftLen = Math.min(nargs, LEFT_ARGS); // absorb some arguments immediately
1493 int rightLen = nargs - leftLen;
1494 MethodHandle leftCollector = newArray.bindTo(nargs);
1495 leftCollector = leftCollector.asCollector(Object[].class, leftLen);
1496 MethodHandle mh = finisher;
1497 if (rightLen > 0) {
1498 MethodHandle rightFiller = fillToRight(LEFT_ARGS + rightLen);
1499 if (mh.equals(getConstantHandle(MH_arrayIdentity)))
1500 mh = rightFiller;
1501 else
1502 mh = MethodHandles.collectArguments(mh, 0, rightFiller);
1503 }
1504 if (mh.equals(getConstantHandle(MH_arrayIdentity)))
1505 mh = leftCollector;
1506 else
1507 mh = MethodHandles.collectArguments(mh, 0, leftCollector);
1508 return mh;
1509 }
1510
1511 private static final int LEFT_ARGS = FILL_ARRAYS_COUNT - 1;
1512 private static final @Stable MethodHandle[] FILL_ARRAY_TO_RIGHT = new MethodHandle[MAX_ARITY + 1];
1513 /** fill_array_to_right(N).invoke(a, argL..arg[N-1])
1514 * fills a[L]..a[N-1] with corresponding arguments,
1515 * and then returns a. The value L is a global constant (LEFT_ARGS).
1516 */
1517 private static MethodHandle fillToRight(int nargs) {
1518 MethodHandle filler = FILL_ARRAY_TO_RIGHT[nargs];
1519 if (filler != null) return filler;
1520 filler = buildFiller(nargs);
1521 assert(assertCorrectArity(filler, nargs - LEFT_ARGS + 1));
1522 return FILL_ARRAY_TO_RIGHT[nargs] = filler;
1523 }
1524 private static MethodHandle buildFiller(int nargs) {
1525 if (nargs <= LEFT_ARGS)
1526 return getConstantHandle(MH_arrayIdentity); // no args to fill; return the array unchanged
1527 // we need room for both mh and a in mh.invoke(a, arg*[nargs])
1528 final int CHUNK = LEFT_ARGS;
1529 int rightLen = nargs % CHUNK;
1530 int midLen = nargs - rightLen;
1531 if (rightLen == 0) {
1532 midLen = nargs - (rightLen = CHUNK);
1533 if (FILL_ARRAY_TO_RIGHT[midLen] == null) {
1534 // build some precursors from left to right
1535 for (int j = LEFT_ARGS % CHUNK; j < midLen; j += CHUNK)
1536 if (j > LEFT_ARGS) fillToRight(j);
1537 }
1538 }
1539 if (midLen < LEFT_ARGS) rightLen = nargs - (midLen = LEFT_ARGS);
1540 assert(rightLen > 0);
1541 MethodHandle midFill = fillToRight(midLen); // recursive fill
1542 MethodHandle rightFill = getFillArray(rightLen).bindTo(midLen); // [midLen..nargs-1]
1543 assert(midFill.type().parameterCount() == 1 + midLen - LEFT_ARGS);
1544 assert(rightFill.type().parameterCount() == 1 + rightLen);
1545
1546 // Combine the two fills:
1547 // right(mid(a, x10..x19), x20..x23)
1548 // The final product will look like this:
1549 // right(mid(newArrayLeft(24, x0..x9), x10..x19), x20..x23)
1550 if (midLen == LEFT_ARGS)
1551 return rightFill;
1552 else
1553 return MethodHandles.collectArguments(rightFill, 0, midFill);
1554 }
1555
1556 static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM
1557
1558 /** Return a method handle that takes the indicated number of
1559 * typed arguments and returns an array of them.
1560 * The type argument is the array type.
1561 */
1562 static MethodHandle varargsArray(Class<?> arrayType, int nargs) {
1563 Class<?> elemType = arrayType.getComponentType();
1564 if (elemType == null) throw new IllegalArgumentException("not an array: "+arrayType);
1565 // FIXME: Need more special casing and caching here.
1566 if (nargs >= MAX_JVM_ARITY/2 - 1) {
1567 int slots = nargs;
1568 final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH
1569 if (slots <= MAX_ARRAY_SLOTS && elemType.isPrimitive())
1570 slots *= Wrapper.forPrimitiveType(elemType).stackSlots();
1571 if (slots > MAX_ARRAY_SLOTS)
1572 throw new IllegalArgumentException("too many arguments: "+arrayType.getSimpleName()+", length "+nargs);
1573 }
1574 if (elemType == Object.class)
1575 return varargsArray(nargs);
1576 // other cases: primitive arrays, subtypes of Object[]
1577 MethodHandle cache[] = Makers.TYPED_COLLECTORS.get(elemType);
1578 MethodHandle mh = nargs < cache.length ? cache[nargs] : null;
1579 if (mh != null) return mh;
1580 if (nargs == 0) {
1581 Object example = java.lang.reflect.Array.newInstance(arrayType.getComponentType(), 0);
1582 mh = MethodHandles.constant(arrayType, example);
1583 } else if (elemType.isPrimitive()) {
1584 MethodHandle builder = getConstantHandle(MH_fillNewArray);
1585 MethodHandle producer = buildArrayProducer(arrayType);
1586 mh = buildVarargsArray(builder, producer, nargs);
1587 } else {
1588 Class<? extends Object[]> objArrayType = arrayType.asSubclass(Object[].class);
1589 Object[] example = Arrays.copyOf(NO_ARGS_ARRAY, 0, objArrayType);
1590 MethodHandle builder = getConstantHandle(MH_fillNewTypedArray).bindTo(example);
1591 MethodHandle producer = getConstantHandle(MH_arrayIdentity); // must be weakly typed
1592 mh = buildVarargsArray(builder, producer, nargs);
1593 }
1594 mh = mh.asType(MethodType.methodType(arrayType, Collections.<Class<?>>nCopies(nargs, elemType)));
1595 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1596 assert(assertCorrectArity(mh, nargs));
1597 if (nargs < cache.length)
1598 cache[nargs] = mh;
1599 return mh;
1600 }
1601
1602 private static MethodHandle buildArrayProducer(Class<?> arrayType) {
1603 Class<?> elemType = arrayType.getComponentType();
1604 assert(elemType.isPrimitive());
1605 return getConstantHandle(MH_copyAsPrimitiveArray).bindTo(Wrapper.forPrimitiveType(elemType));
1606 }
1607
1608 /*non-public*/ static void assertSame(Object mh1, Object mh2) {
1609 if (mh1 != mh2) {
1610 String msg = String.format("mh1 != mh2: mh1 = %s (form: %s); mh2 = %s (form: %s)",
1611 mh1, ((MethodHandle)mh1).form,
1612 mh2, ((MethodHandle)mh2).form);
1613 throw newInternalError(msg);
1614 }
1615 }
1616
1617 // Local constant functions:
1618 /*non-public*/ static final NamedFunction
1619 NF_checkSpreadArgument,
1620 NF_guardWithCatch,
1621 NF_throwException,
1622 NF_profileBoolean;
1623
1624 static {
1625 try {
1626 NF_checkSpreadArgument = new NamedFunction(MethodHandleImpl.class
1627 .getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
1628 NF_guardWithCatch = new NamedFunction(MethodHandleImpl.class
1629 .getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class,
1630 MethodHandle.class, Object[].class));
1631 NF_throwException = new NamedFunction(MethodHandleImpl.class
1632 .getDeclaredMethod("throwException", Throwable.class));
1633 NF_profileBoolean = new NamedFunction(MethodHandleImpl.class
1634 .getDeclaredMethod("profileBoolean", boolean.class, int[].class));
1635 } catch (ReflectiveOperationException ex) {
1636 throw newInternalError(ex);
1637 }
1638 }
1639
1640 /**
1641 * Assembles a loop method handle from the given handles and type information. This works by binding and configuring
1642 * the {@linkplain #looper(MethodHandle[], MethodHandle[], MethodHandle[], MethodHandle[], int, int, Object[]) "most
1643 * generic loop"}.
1644 *
1645 * @param tloop the return type of the loop.
1646 * @param targs types of the arguments to be passed to the loop.
1647 * @param tvars types of loop-local variables.
1648 * @param init sanitized array of initializers for loop-local variables.
1649 * @param step sanitited array of loop bodies.
1650 * @param pred sanitized array of predicates.
1651 * @param fini sanitized array of loop finalizers.
1652 *
1653 * @return a handle that, when invoked, will execute the loop.
1654 */
1655 static MethodHandle makeLoop(Class<?> tloop, List<Class<?>> targs, List<Class<?>> tvars, List<MethodHandle> init,
1656 List<MethodHandle> step, List<MethodHandle> pred, List<MethodHandle> fini) {
1657 MethodHandle[] ainit = toArrayArgs(init);
1658 MethodHandle[] astep = toArrayArgs(step);
1659 MethodHandle[] apred = toArrayArgs(pred);
1660 MethodHandle[] afini = toArrayArgs(fini);
1661
1662 MethodHandle l = getConstantHandle(MH_looper);
1663
1664 // Bind the statically known arguments.
1665 l = MethodHandles.insertArguments(l, 0, ainit, astep, apred, afini, tvars.size(), targs.size());
1666
1667 // Turn the args array into an argument list.
1668 l = l.asCollector(Object[].class, targs.size());
1669
1670 // Finally, make loop type.
1671 MethodType loopType = MethodType.methodType(tloop, targs);
1672 l = l.asType(loopType);
1673
1674 return l;
1675 }
1676
1677 /**
1678 * Converts all handles in the {@code hs} array to handles that accept an array of arguments.
1679 *
1680 * @param hs method handles to be converted.
1681 *
1682 * @return the {@code hs} array, with all method handles therein converted.
1683 */
1684 static MethodHandle[] toArrayArgs(List<MethodHandle> hs) {
1685 return hs.stream().map(h -> h.asSpreader(Object[].class, h.type().parameterCount())).toArray(MethodHandle[]::new);
1686 }
1687
1688 /**
1689 * This method embodies the most generic loop for use by {@link MethodHandles#loop(MethodHandle[][])}. A handle on
1690 * it will be transformed into a handle on a concrete loop instantiation by {@link #makeLoop}.
1691 *
1692 * @param init loop-local variable initializers.
1693 * @param step bodies.
1694 * @param pred predicates.
1695 * @param fini finalizers.
1696 * @param varSize number of loop-local variables.
1697 * @param nArgs number of arguments passed to the loop.
1698 * @param args arguments to the loop invocation.
1699 *
1700 * @return the result of executing the loop.
1701 */
1702 static Object looper(MethodHandle[] init, MethodHandle[] step, MethodHandle[] pred, MethodHandle[] fini,
1703 int varSize, int nArgs, Object[] args) throws Throwable {
1704 Object[] varsAndArgs = new Object[varSize + nArgs];
1705 for (int i = 0, v = 0; i < init.length; ++i) {
1706 if (init[i].type().returnType() == void.class) {
1707 init[i].invoke(args);
1708 } else {
1709 varsAndArgs[v++] = init[i].invoke(args);
1710 }
1711 }
1712 System.arraycopy(args, 0, varsAndArgs, varSize, nArgs);
1713 final int nSteps = step.length;
1714 for (; ; ) {
1715 for (int i = 0, v = 0; i < nSteps; ++i) {
1716 MethodHandle p = pred[i];
1717 MethodHandle s = step[i];
1718 MethodHandle f = fini[i];
1719 if (s.type().returnType() == void.class) {
1720 s.invoke(varsAndArgs);
1721 } else {
1722 varsAndArgs[v++] = s.invoke(varsAndArgs);
1723 }
1724 if (!(boolean) p.invoke(varsAndArgs)) {
1725 return f.invoke(varsAndArgs);
1726 }
1727 }
1728 }
1729 }
1730
1731 /**
1732 * This method is bound as the predicate in {@linkplain MethodHandles#countedLoop(MethodHandle, MethodHandle,
1733 * MethodHandle) counting loops}.
1734 *
1735 * @param counter the counter parameter, passed in during loop execution.
1736 * @param limit the upper bound of the parameter, statically bound at loop creation time.
1737 *
1738 * @return whether the counter has reached the limit.
1739 */
1740 static boolean countedLoopPredicate(int counter, int limit) {
1741 return counter <= limit;
1742 }
1743
1744 /**
1745 * This method is bound as the step function in {@linkplain MethodHandles#countedLoop(MethodHandle, MethodHandle,
1746 * MethodHandle) counting loops} to increment the counter.
1747 *
1748 * @param counter the loop counter.
1749 *
1750 * @return the loop counter incremented by 1.
1751 */
1752 static int countedLoopStep(int counter, int limit) {
1753 return counter + 1;
1754 }
1755
1756 /**
1757 * This method is bound as a filter in {@linkplain MethodHandles#countedLoop(MethodHandle, MethodHandle, MethodHandle,
1758 * MethodHandle) counting loops} to pass the correct counter value to the body.
1759 *
1760 * @param counter the loop counter.
1761 *
1762 * @return the loop counter decremented by 1.
1763 */
1764 static int decrementCounter(int counter) {
1765 return counter - 1;
1766 }
1767
1768 /**
1769 * This is bound to initialize the loop-local iterator in {@linkplain MethodHandles#iteratedLoop iterating loops}.
1770 *
1771 * @param it the {@link Iterable} over which the loop iterates.
1772 *
1773 * @return an {@link Iterator} over the argument's elements.
1774 */
1775 static Iterator<?> initIterator(Iterable<?> it) {
1776 return it.iterator();
1777 }
1778
1779 /**
1780 * This method is bound as the predicate in {@linkplain MethodHandles#iteratedLoop iterating loops}.
1781 *
1782 * @param it the iterator to be checked.
1783 *
1784 * @return {@code true} iff there are more elements to iterate over.
1785 */
1786 static boolean iteratePredicate(Iterator<?> it) {
1787 return it.hasNext();
1788 }
1789
1790 /**
1791 * This method is bound as the step for retrieving the current value from the iterator in {@linkplain
1792 * MethodHandles#iteratedLoop iterating loops}.
1793 *
1794 * @param it the iterator.
1795 *
1796 * @return the next element from the iterator.
1797 */
1798 static Object iterateNext(Iterator<?> it) {
1799 return it.next();
1800 }
1801
1802 /**
1803 * Makes a {@code try-finally} handle that conforms to the type constraints.
1804 *
1805 * @param target the target to execute in a {@code try-finally} block.
1806 * @param cleanup the cleanup to execute in the {@code finally} block.
1807 * @param type the result type of the entire construct.
1808 * @param argTypes the types of the arguments.
1809 *
1810 * @return a handle on the constructed {@code try-finally} block.
1811 */
1812 static MethodHandle makeTryFinally(MethodHandle target, MethodHandle cleanup, Class<?> type, List<Class<?>> argTypes) {
1813 MethodHandle tf = getConstantHandle(type == void.class ? MH_tryFinallyVoidExec : MH_tryFinallyExec);
1814
1815 // Bind the statically known arguments.
1816 tf = MethodHandles.insertArguments(tf, 0, target, cleanup);
1817
1818 // Turn the args array into an argument list.
1819 tf = tf.asCollector(Object[].class, argTypes.size());
1820
1821 // Finally, make try-finally type.
1822 MethodType tfType = MethodType.methodType(type, argTypes);
1823 tf = tf.asType(tfType);
1824
1825 return tf;
1826 }
1827
1828 /**
1829 * A method that will be bound during construction of a {@code try-finally} handle with non-{@code void} return type
1830 * by {@link MethodHandles#tryFinally(MethodHandle, MethodHandle)}.
1831 *
1832 * @param target the handle to wrap in a {@code try-finally} block. This will be bound.
1833 * @param cleanup the handle to run in any case before returning. This will be bound.
1834 * @param args the arguments to the call. These will remain as the argument list.
1835 *
1836 * @return whatever the execution of the {@code target} returned (it may have been modified by the execution of
1837 * {@code cleanup}).
1838 * @throws Throwable in case anything is thrown by the execution of {@code target}, the {@link Throwable} will be
1839 * passed to the {@code cleanup} handle, which may decide to throw any exception it sees fit.
1840 */
1841 static Object tryFinallyExecutor(MethodHandle target, MethodHandle cleanup, Object[] args) throws Throwable {
1842 Throwable t = null;
1843 Object r = null;
1844 try {
1845 r = target.invoke(args);
1846 } catch (Throwable thrown) {
1847 t = thrown;
1848 throw t;
1849 } finally {
1850 r = cleanup.invoke(t, r, args);
1851 }
1852 return r;
1853 }
1854
1855 /**
1856 * A method that will be bound during construction of a {@code try-finally} handle with {@code void} return type by
1857 * {@link MethodHandles#tryFinally(MethodHandle, MethodHandle)}.
1858 *
1859 * @param target the handle to wrap in a {@code try-finally} block. This will be bound.
1860 * @param cleanup the handle to run in any case before returning. This will be bound.
1861 * @param args the arguments to the call. These will remain as the argument list.
1862 *
1863 * @throws Throwable in case anything is thrown by the execution of {@code target}, the {@link Throwable} will be
1864 * passed to the {@code cleanup} handle, which may decide to throw any exception it sees fit.
1865 */
1866 static void tryFinallyVoidExecutor(MethodHandle target, MethodHandle cleanup, Object[] args) throws Throwable {
1867 Throwable t = null;
1868 try {
1869 target.invoke(args);
1870 } catch (Throwable thrown) {
1871 t = thrown;
1872 throw t;
1873 } finally {
1874 cleanup.invoke(t, args);
1875 }
1876 }
1877
1878 // Indexes into constant method handles:
1879 static final int
1880 MH_cast = 0,
1881 MH_selectAlternative = 1,
1882 MH_copyAsPrimitiveArray = 2,
1883 MH_fillNewTypedArray = 3,
1884 MH_fillNewArray = 4,
1885 MH_arrayIdentity = 5,
1886 MH_looper = 6,
1887 MH_countedLoopPred = 7,
1888 MH_countedLoopStep = 8,
1889 MH_iteratePred = 9,
1890 MH_initIterator = 10,
1891 MH_iterateNext = 11,
1892 MH_tryFinallyExec = 12,
1893 MH_tryFinallyVoidExec = 13,
1894 MH_decrementCounter = 14,
1895 MH_LIMIT = 15;
1896
1897 static MethodHandle getConstantHandle(int idx) {
1898 MethodHandle handle = HANDLES[idx];
1899 if (handle != null) {
1900 return handle;
1901 }
1902 return setCachedHandle(idx, makeConstantHandle(idx));
1903 }
1904
1905 private static synchronized MethodHandle setCachedHandle(int idx, final MethodHandle method) {
1906 // Simulate a CAS, to avoid racy duplication of results.
1907 MethodHandle prev = HANDLES[idx];
1908 if (prev != null) {
1909 return prev;
1910 }
1911 HANDLES[idx] = method;
1912 return method;
1913 }
1914
1915 // Local constant method handles:
1916 private static final @Stable MethodHandle[] HANDLES = new MethodHandle[MH_LIMIT];
1917
1918 private static MethodHandle makeConstantHandle(int idx) {
1919 try {
1920 switch (idx) {
1921 case MH_cast:
1922 return IMPL_LOOKUP.findVirtual(Class.class, "cast",
1923 MethodType.methodType(Object.class, Object.class));
1924 case MH_copyAsPrimitiveArray:
1925 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "copyAsPrimitiveArray",
1926 MethodType.methodType(Object.class, Wrapper.class, Object[].class));
1927 case MH_arrayIdentity:
1928 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "identity",
1929 MethodType.methodType(Object[].class, Object[].class));
1930 case MH_fillNewArray:
1931 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "fillNewArray",
1932 MethodType.methodType(Object[].class, Integer.class, Object[].class));
1933 case MH_fillNewTypedArray:
1934 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "fillNewTypedArray",
1935 MethodType.methodType(Object[].class, Object[].class, Integer.class, Object[].class));
1936 case MH_selectAlternative:
1937 return makeIntrinsic(IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "selectAlternative",
1938 MethodType.methodType(MethodHandle.class, boolean.class, MethodHandle.class, MethodHandle.class)),
1939 Intrinsic.SELECT_ALTERNATIVE);
1940 case MH_looper:
1941 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "looper", MethodType.methodType(Object.class,
1942 MethodHandle[].class, MethodHandle[].class, MethodHandle[].class, MethodHandle[].class,
1943 int.class, int.class, Object[].class));
1944 case MH_countedLoopPred:
1945 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "countedLoopPredicate",
1946 MethodType.methodType(boolean.class, int.class, int.class));
1947 case MH_countedLoopStep:
1948 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "countedLoopStep",
1949 MethodType.methodType(int.class, int.class, int.class));
1950 case MH_iteratePred:
1951 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "iteratePredicate",
1952 MethodType.methodType(boolean.class, Iterator.class));
1953 case MH_initIterator:
1954 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "initIterator",
1955 MethodType.methodType(Iterator.class, Iterable.class));
1956 case MH_iterateNext:
1957 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "iterateNext",
1958 MethodType.methodType(Object.class, Iterator.class));
1959 case MH_tryFinallyExec:
1960 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "tryFinallyExecutor",
1961 MethodType.methodType(Object.class, MethodHandle.class, MethodHandle.class, Object[].class));
1962 case MH_tryFinallyVoidExec:
1963 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "tryFinallyVoidExecutor",
1964 MethodType.methodType(void.class, MethodHandle.class, MethodHandle.class, Object[].class));
1965 case MH_decrementCounter:
1966 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "decrementCounter",
1967 MethodType.methodType(int.class, int.class));
1968 }
1969 } catch (ReflectiveOperationException ex) {
1970 throw newInternalError(ex);
1971 }
1972 throw newInternalError("Unknown function index: " + idx);
1973 }
1974 }