1 /*
2 * Copyright (c) 2008, 2017, 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 jdk.internal.misc.JavaLangInvokeAccess;
29 import jdk.internal.misc.SharedSecrets;
30 import jdk.internal.org.objectweb.asm.AnnotationVisitor;
31 import jdk.internal.org.objectweb.asm.ClassWriter;
32 import jdk.internal.org.objectweb.asm.MethodVisitor;
33 import jdk.internal.reflect.CallerSensitive;
34 import jdk.internal.reflect.Reflection;
35 import jdk.internal.vm.annotation.ForceInline;
36 import jdk.internal.vm.annotation.Stable;
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
42 import java.lang.reflect.Array;
43 import java.util.Arrays;
44 import java.util.Collections;
45 import java.util.Iterator;
46 import java.util.List;
47 import java.util.Map;
48 import java.util.function.Function;
49 import java.util.stream.Stream;
50
51 import static java.lang.invoke.LambdaForm.*;
52 import static java.lang.invoke.MethodHandleStatics.*;
53 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
54 import static jdk.internal.org.objectweb.asm.Opcodes.*;
55
56 /**
57 * Trusted implementation code for MethodHandle.
58 * @author jrose
59 */
60 /*non-public*/ abstract class MethodHandleImpl {
61
62 /// Factory methods to create method handles:
63
64 static MethodHandle makeArrayElementAccessor(Class<?> arrayClass, ArrayAccess access) {
65 if (arrayClass == Object[].class) {
66 return ArrayAccess.objectAccessor(access);
67 }
68 if (!arrayClass.isArray())
69 throw newIllegalArgumentException("not an array: "+arrayClass);
70 MethodHandle[] cache = ArrayAccessor.TYPED_ACCESSORS.get(arrayClass);
71 int cacheIndex = ArrayAccess.cacheIndex(access);
72 MethodHandle mh = cache[cacheIndex];
73 if (mh != null) return mh;
74 mh = ArrayAccessor.getAccessor(arrayClass, access);
75 MethodType correctType = ArrayAccessor.correctType(arrayClass, access);
76 if (mh.type() != correctType) {
77 assert(mh.type().parameterType(0) == Object[].class);
78 /* if access == SET */ assert(access != ArrayAccess.SET || mh.type().parameterType(2) == Object.class);
79 /* if access == GET */ assert(access != ArrayAccess.GET ||
80 (mh.type().returnType() == Object.class &&
81 correctType.parameterType(0).getComponentType() == correctType.returnType()));
82 // safe to view non-strictly, because element type follows from array type
83 mh = mh.viewAsType(correctType, false);
84 }
85 mh = makeIntrinsic(mh, ArrayAccess.intrinsic(access));
86 // Atomically update accessor cache.
87 synchronized(cache) {
88 if (cache[cacheIndex] == null) {
89 cache[cacheIndex] = mh;
90 } else {
91 // Throw away newly constructed accessor and use cached version.
92 mh = cache[cacheIndex];
93 }
94 }
95 return mh;
96 }
97
98 enum ArrayAccess {
99 GET, SET, LENGTH;
100
101 // As ArrayAccess and ArrayAccessor have a circular dependency, the ArrayAccess properties cannot be stored in
102 // final fields.
103
104 static String opName(ArrayAccess a) {
105 switch (a) {
106 case GET: return "getElement";
107 case SET: return "setElement";
108 case LENGTH: return "length";
109 }
110 throw unmatchedArrayAccess(a);
111 }
112
113 static MethodHandle objectAccessor(ArrayAccess a) {
114 switch (a) {
115 case GET: return ArrayAccessor.OBJECT_ARRAY_GETTER;
116 case SET: return ArrayAccessor.OBJECT_ARRAY_SETTER;
117 case LENGTH: return ArrayAccessor.OBJECT_ARRAY_LENGTH;
118 }
119 throw unmatchedArrayAccess(a);
120 }
121
122 static int cacheIndex(ArrayAccess a) {
123 switch (a) {
124 case GET: return ArrayAccessor.GETTER_INDEX;
125 case SET: return ArrayAccessor.SETTER_INDEX;
126 case LENGTH: return ArrayAccessor.LENGTH_INDEX;
127 }
128 throw unmatchedArrayAccess(a);
129 }
130
131 static Intrinsic intrinsic(ArrayAccess a) {
132 switch (a) {
133 case GET: return Intrinsic.ARRAY_LOAD;
134 case SET: return Intrinsic.ARRAY_STORE;
135 case LENGTH: return Intrinsic.ARRAY_LENGTH;
136 }
137 throw unmatchedArrayAccess(a);
138 }
139 }
140
141 static InternalError unmatchedArrayAccess(ArrayAccess a) {
142 return newInternalError("should not reach here (unmatched ArrayAccess: " + a + ")");
143 }
144
145 static final class ArrayAccessor {
146 /// Support for array element and length access
147 static final int GETTER_INDEX = 0, SETTER_INDEX = 1, LENGTH_INDEX = 2, INDEX_LIMIT = 3;
148 static final ClassValue<MethodHandle[]> TYPED_ACCESSORS
149 = new ClassValue<MethodHandle[]>() {
150 @Override
151 protected MethodHandle[] computeValue(Class<?> type) {
152 return new MethodHandle[INDEX_LIMIT];
153 }
154 };
155 static final MethodHandle OBJECT_ARRAY_GETTER, OBJECT_ARRAY_SETTER, OBJECT_ARRAY_LENGTH;
156 static {
157 MethodHandle[] cache = TYPED_ACCESSORS.get(Object[].class);
158 cache[GETTER_INDEX] = OBJECT_ARRAY_GETTER = makeIntrinsic(getAccessor(Object[].class, ArrayAccess.GET), Intrinsic.ARRAY_LOAD);
159 cache[SETTER_INDEX] = OBJECT_ARRAY_SETTER = makeIntrinsic(getAccessor(Object[].class, ArrayAccess.SET), Intrinsic.ARRAY_STORE);
160 cache[LENGTH_INDEX] = OBJECT_ARRAY_LENGTH = makeIntrinsic(getAccessor(Object[].class, ArrayAccess.LENGTH), Intrinsic.ARRAY_LENGTH);
161
162 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_GETTER.internalMemberName()));
163 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_SETTER.internalMemberName()));
164 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_LENGTH.internalMemberName()));
165 }
166
167 static int getElementI(int[] a, int i) { return a[i]; }
168 static long getElementJ(long[] a, int i) { return a[i]; }
169 static float getElementF(float[] a, int i) { return a[i]; }
170 static double getElementD(double[] a, int i) { return a[i]; }
171 static boolean getElementZ(boolean[] a, int i) { return a[i]; }
172 static byte getElementB(byte[] a, int i) { return a[i]; }
173 static short getElementS(short[] a, int i) { return a[i]; }
174 static char getElementC(char[] a, int i) { return a[i]; }
175 static Object getElementL(Object[] a, int i) { return a[i]; }
176
177 static void setElementI(int[] a, int i, int x) { a[i] = x; }
178 static void setElementJ(long[] a, int i, long x) { a[i] = x; }
179 static void setElementF(float[] a, int i, float x) { a[i] = x; }
180 static void setElementD(double[] a, int i, double x) { a[i] = x; }
181 static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; }
182 static void setElementB(byte[] a, int i, byte x) { a[i] = x; }
183 static void setElementS(short[] a, int i, short x) { a[i] = x; }
184 static void setElementC(char[] a, int i, char x) { a[i] = x; }
185 static void setElementL(Object[] a, int i, Object x) { a[i] = x; }
186
187 static int lengthI(int[] a) { return a.length; }
188 static int lengthJ(long[] a) { return a.length; }
189 static int lengthF(float[] a) { return a.length; }
190 static int lengthD(double[] a) { return a.length; }
191 static int lengthZ(boolean[] a) { return a.length; }
192 static int lengthB(byte[] a) { return a.length; }
193 static int lengthS(short[] a) { return a.length; }
194 static int lengthC(char[] a) { return a.length; }
195 static int lengthL(Object[] a) { return a.length; }
196
197 static String name(Class<?> arrayClass, ArrayAccess access) {
198 Class<?> elemClass = arrayClass.getComponentType();
199 if (elemClass == null) throw newIllegalArgumentException("not an array", arrayClass);
200 return ArrayAccess.opName(access) + Wrapper.basicTypeChar(elemClass);
201 }
202 static MethodType type(Class<?> arrayClass, ArrayAccess access) {
203 Class<?> elemClass = arrayClass.getComponentType();
204 Class<?> arrayArgClass = arrayClass;
205 if (!elemClass.isPrimitive()) {
206 arrayArgClass = Object[].class;
207 elemClass = Object.class;
208 }
209 switch (access) {
210 case GET: return MethodType.methodType(elemClass, arrayArgClass, int.class);
211 case SET: return MethodType.methodType(void.class, arrayArgClass, int.class, elemClass);
212 case LENGTH: return MethodType.methodType(int.class, arrayArgClass);
213 }
214 throw unmatchedArrayAccess(access);
215 }
216 static MethodType correctType(Class<?> arrayClass, ArrayAccess access) {
217 Class<?> elemClass = arrayClass.getComponentType();
218 switch (access) {
219 case GET: return MethodType.methodType(elemClass, arrayClass, int.class);
220 case SET: return MethodType.methodType(void.class, arrayClass, int.class, elemClass);
221 case LENGTH: return MethodType.methodType(int.class, arrayClass);
222 }
223 throw unmatchedArrayAccess(access);
224 }
225 static MethodHandle getAccessor(Class<?> arrayClass, ArrayAccess access) {
226 String name = name(arrayClass, access);
227 MethodType type = type(arrayClass, access);
228 try {
229 return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type);
230 } catch (ReflectiveOperationException ex) {
231 throw uncaughtException(ex);
232 }
233 }
234 }
235
236 /**
237 * Create a JVM-level adapter method handle to conform the given method
238 * handle to the similar newType, using only pairwise argument conversions.
239 * For each argument, convert incoming argument to the exact type needed.
240 * The argument conversions allowed are casting, boxing and unboxing,
241 * integral widening or narrowing, and floating point widening or narrowing.
242 * @param srcType required call type
243 * @param target original method handle
244 * @param strict if true, only asType conversions are allowed; if false, explicitCastArguments conversions allowed
245 * @param monobox if true, unboxing conversions are assumed to be exactly typed (Integer to int only, not long or double)
246 * @return an adapter to the original handle with the desired new type,
247 * or the original target if the types are already identical
248 * or null if the adaptation cannot be made
249 */
250 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
251 boolean strict, boolean monobox) {
252 MethodType dstType = target.type();
253 if (srcType == dstType)
254 return target;
255 return makePairwiseConvertByEditor(target, srcType, strict, monobox);
256 }
257
258 private static int countNonNull(Object[] array) {
259 int count = 0;
260 for (Object x : array) {
261 if (x != null) ++count;
262 }
263 return count;
264 }
265
266 static MethodHandle makePairwiseConvertByEditor(MethodHandle target, MethodType srcType,
267 boolean strict, boolean monobox) {
268 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
269 int convCount = countNonNull(convSpecs);
270 if (convCount == 0)
271 return target.viewAsType(srcType, strict);
272 MethodType basicSrcType = srcType.basicType();
273 MethodType midType = target.type().basicType();
274 BoundMethodHandle mh = target.rebind();
275 // FIXME: Reduce number of bindings when there is more than one Class conversion.
276 // FIXME: Reduce number of bindings when there are repeated conversions.
277 for (int i = 0; i < convSpecs.length-1; i++) {
278 Object convSpec = convSpecs[i];
279 if (convSpec == null) continue;
280 MethodHandle fn;
281 if (convSpec instanceof Class) {
282 fn = getConstantHandle(MH_cast).bindTo(convSpec);
283 } else {
284 fn = (MethodHandle) convSpec;
285 }
286 Class<?> newType = basicSrcType.parameterType(i);
287 if (--convCount == 0)
288 midType = srcType;
289 else
290 midType = midType.changeParameterType(i, newType);
291 LambdaForm form2 = mh.editor().filterArgumentForm(1+i, BasicType.basicType(newType));
292 mh = mh.copyWithExtendL(midType, form2, fn);
293 mh = mh.rebind();
294 }
295 Object convSpec = convSpecs[convSpecs.length-1];
296 if (convSpec != null) {
297 MethodHandle fn;
298 if (convSpec instanceof Class) {
299 if (convSpec == void.class)
300 fn = null;
301 else
302 fn = getConstantHandle(MH_cast).bindTo(convSpec);
303 } else {
304 fn = (MethodHandle) convSpec;
305 }
306 Class<?> newType = basicSrcType.returnType();
307 assert(--convCount == 0);
308 midType = srcType;
309 if (fn != null) {
310 mh = mh.rebind(); // rebind if too complex
311 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), false);
312 mh = mh.copyWithExtendL(midType, form2, fn);
313 } else {
314 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), true);
315 mh = mh.copyWith(midType, form2);
316 }
317 }
318 assert(convCount == 0);
319 assert(mh.type().equals(srcType));
320 return mh;
321 }
322
323 static MethodHandle makePairwiseConvertIndirect(MethodHandle target, MethodType srcType,
324 boolean strict, boolean monobox) {
325 assert(target.type().parameterCount() == srcType.parameterCount());
326 // Calculate extra arguments (temporaries) required in the names array.
327 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox);
328 final int INARG_COUNT = srcType.parameterCount();
329 int convCount = countNonNull(convSpecs);
330 boolean retConv = (convSpecs[INARG_COUNT] != null);
331 boolean retVoid = srcType.returnType() == void.class;
332 if (retConv && retVoid) {
333 convCount -= 1;
334 retConv = false;
335 }
336
337 final int IN_MH = 0;
338 final int INARG_BASE = 1;
339 final int INARG_LIMIT = INARG_BASE + INARG_COUNT;
340 final int NAME_LIMIT = INARG_LIMIT + convCount + 1;
341 final int RETURN_CONV = (!retConv ? -1 : NAME_LIMIT - 1);
342 final int OUT_CALL = (!retConv ? NAME_LIMIT : RETURN_CONV) - 1;
343 final int RESULT = (retVoid ? -1 : NAME_LIMIT - 1);
344
345 // Now build a LambdaForm.
346 MethodType lambdaType = srcType.basicType().invokerType();
347 Name[] names = arguments(NAME_LIMIT - INARG_LIMIT, lambdaType);
348
349 // Collect the arguments to the outgoing call, maybe with conversions:
350 final int OUTARG_BASE = 0; // target MH is Name.function, name Name.arguments[0]
351 Object[] outArgs = new Object[OUTARG_BASE + INARG_COUNT];
352
353 int nameCursor = INARG_LIMIT;
354 for (int i = 0; i < INARG_COUNT; i++) {
355 Object convSpec = convSpecs[i];
356 if (convSpec == null) {
357 // do nothing: difference is trivial
358 outArgs[OUTARG_BASE + i] = names[INARG_BASE + i];
359 continue;
360 }
361
362 Name conv;
363 if (convSpec instanceof Class) {
364 Class<?> convClass = (Class<?>) convSpec;
365 conv = new Name(getConstantHandle(MH_cast), convClass, names[INARG_BASE + i]);
366 } else {
367 MethodHandle fn = (MethodHandle) convSpec;
368 conv = new Name(fn, names[INARG_BASE + i]);
369 }
370 assert(names[nameCursor] == null);
371 names[nameCursor++] = conv;
372 assert(outArgs[OUTARG_BASE + i] == null);
373 outArgs[OUTARG_BASE + i] = conv;
374 }
375
376 // Build argument array for the call.
377 assert(nameCursor == OUT_CALL);
378 names[OUT_CALL] = new Name(target, outArgs);
379
380 Object convSpec = convSpecs[INARG_COUNT];
381 if (!retConv) {
382 assert(OUT_CALL == names.length-1);
383 } else {
384 Name conv;
385 if (convSpec == void.class) {
386 conv = new Name(LambdaForm.constantZero(BasicType.basicType(srcType.returnType())));
387 } else if (convSpec instanceof Class) {
388 Class<?> convClass = (Class<?>) convSpec;
389 conv = new Name(getConstantHandle(MH_cast), convClass, names[OUT_CALL]);
390 } else {
391 MethodHandle fn = (MethodHandle) convSpec;
392 if (fn.type().parameterCount() == 0)
393 conv = new Name(fn); // don't pass retval to void conversion
394 else
395 conv = new Name(fn, names[OUT_CALL]);
396 }
397 assert(names[RETURN_CONV] == null);
398 names[RETURN_CONV] = conv;
399 assert(RETURN_CONV == names.length-1);
400 }
401
402 LambdaForm form = new LambdaForm(lambdaType.parameterCount(), names, RESULT, Kind.CONVERT);
403 return SimpleMethodHandle.make(srcType, form);
404 }
405
406 static Object[] computeValueConversions(MethodType srcType, MethodType dstType,
407 boolean strict, boolean monobox) {
408 final int INARG_COUNT = srcType.parameterCount();
409 Object[] convSpecs = new Object[INARG_COUNT+1];
410 for (int i = 0; i <= INARG_COUNT; i++) {
411 boolean isRet = (i == INARG_COUNT);
412 Class<?> src = isRet ? dstType.returnType() : srcType.parameterType(i);
413 Class<?> dst = isRet ? srcType.returnType() : dstType.parameterType(i);
414 if (!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)) {
415 convSpecs[i] = valueConversion(src, dst, strict, monobox);
416 }
417 }
418 return convSpecs;
419 }
420 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType,
421 boolean strict) {
422 return makePairwiseConvert(target, srcType, strict, /*monobox=*/ false);
423 }
424
425 /**
426 * Find a conversion function from the given source to the given destination.
427 * This conversion function will be used as a LF NamedFunction.
428 * Return a Class object if a simple cast is needed.
429 * Return void.class if void is involved.
430 */
431 static Object valueConversion(Class<?> src, Class<?> dst, boolean strict, boolean monobox) {
432 assert(!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)); // caller responsibility
433 if (dst == void.class)
434 return dst;
435 MethodHandle fn;
436 if (src.isPrimitive()) {
437 if (src == void.class) {
438 return void.class; // caller must recognize this specially
439 } else if (dst.isPrimitive()) {
440 // Examples: int->byte, byte->int, boolean->int (!strict)
441 fn = ValueConversions.convertPrimitive(src, dst);
442 } else {
443 // Examples: int->Integer, boolean->Object, float->Number
444 Wrapper wsrc = Wrapper.forPrimitiveType(src);
445 fn = ValueConversions.boxExact(wsrc);
446 assert(fn.type().parameterType(0) == wsrc.primitiveType());
447 assert(fn.type().returnType() == wsrc.wrapperType());
448 if (!VerifyType.isNullConversion(wsrc.wrapperType(), dst, strict)) {
449 // Corner case, such as int->Long, which will probably fail.
450 MethodType mt = MethodType.methodType(dst, src);
451 if (strict)
452 fn = fn.asType(mt);
453 else
454 fn = MethodHandleImpl.makePairwiseConvert(fn, mt, /*strict=*/ false);
455 }
456 }
457 } else if (dst.isPrimitive()) {
458 Wrapper wdst = Wrapper.forPrimitiveType(dst);
459 if (monobox || src == wdst.wrapperType()) {
460 // Use a strongly-typed unboxer, if possible.
461 fn = ValueConversions.unboxExact(wdst, strict);
462 } else {
463 // Examples: Object->int, Number->int, Comparable->int, Byte->int
464 // must include additional conversions
465 // src must be examined at runtime, to detect Byte, Character, etc.
466 fn = (strict
467 ? ValueConversions.unboxWiden(wdst)
468 : ValueConversions.unboxCast(wdst));
469 }
470 } else {
471 // Simple reference conversion.
472 // Note: Do not check for a class hierarchy relation
473 // between src and dst. In all cases a 'null' argument
474 // will pass the cast conversion.
475 return dst;
476 }
477 assert(fn.type().parameterCount() <= 1) : "pc"+Arrays.asList(src.getSimpleName(), dst.getSimpleName(), fn);
478 return fn;
479 }
480
481 static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
482 MethodType type = target.type();
483 int last = type.parameterCount() - 1;
484 if (type.parameterType(last) != arrayType)
485 target = target.asType(type.changeParameterType(last, arrayType));
486 target = target.asFixedArity(); // make sure this attribute is turned off
487 return new AsVarargsCollector(target, arrayType);
488 }
489
490 private static final class AsVarargsCollector extends DelegatingMethodHandle {
491 private final MethodHandle target;
492 private final Class<?> arrayType;
493 private @Stable MethodHandle asCollectorCache;
494
495 AsVarargsCollector(MethodHandle target, Class<?> arrayType) {
496 this(target.type(), target, arrayType);
497 }
498 AsVarargsCollector(MethodType type, MethodHandle target, Class<?> arrayType) {
499 super(type, target);
500 this.target = target;
501 this.arrayType = arrayType;
502 this.asCollectorCache = target.asCollector(arrayType, 0);
503 }
504
505 @Override
506 public boolean isVarargsCollector() {
507 return true;
508 }
509
510 @Override
511 protected MethodHandle getTarget() {
512 return target;
513 }
514
515 @Override
516 public MethodHandle asFixedArity() {
517 return target;
518 }
519
520 @Override
521 MethodHandle setVarargs(MemberName member) {
522 if (member.isVarargs()) return this;
523 return asFixedArity();
524 }
525
526 @Override
527 public MethodHandle withVarargs(boolean makeVarargs) {
528 if (makeVarargs) return this;
529 return asFixedArity();
530 }
531
532 @Override
533 public MethodHandle asTypeUncached(MethodType newType) {
534 MethodType type = this.type();
535 int collectArg = type.parameterCount() - 1;
536 int newArity = newType.parameterCount();
537 if (newArity == collectArg+1 &&
538 type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
539 // if arity and trailing parameter are compatible, do normal thing
540 return asTypeCache = asFixedArity().asType(newType);
541 }
542 // check cache
543 MethodHandle acc = asCollectorCache;
544 if (acc != null && acc.type().parameterCount() == newArity)
545 return asTypeCache = acc.asType(newType);
546 // build and cache a collector
547 int arrayLength = newArity - collectArg;
548 MethodHandle collector;
549 try {
550 collector = asFixedArity().asCollector(arrayType, arrayLength);
551 assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
552 } catch (IllegalArgumentException ex) {
553 throw new WrongMethodTypeException("cannot build collector", ex);
554 }
555 asCollectorCache = collector;
556 return asTypeCache = collector.asType(newType);
557 }
558
559 @Override
560 boolean viewAsTypeChecks(MethodType newType, boolean strict) {
561 super.viewAsTypeChecks(newType, true);
562 if (strict) return true;
563 // extra assertion for non-strict checks:
564 assert (type().lastParameterType().getComponentType()
565 .isAssignableFrom(
566 newType.lastParameterType().getComponentType()))
567 : Arrays.asList(this, newType);
568 return true;
569 }
570
571 @Override
572 public Object invokeWithArguments(Object... arguments) throws Throwable {
573 MethodType type = this.type();
574 int argc;
575 final int MAX_SAFE = 127; // 127 longs require 254 slots, which is safe to spread
576 if (arguments == null
577 || (argc = arguments.length) <= MAX_SAFE
578 || argc < type.parameterCount()) {
579 return super.invokeWithArguments(arguments);
580 }
581
582 // a jumbo invocation requires more explicit reboxing of the trailing arguments
583 int uncollected = type.parameterCount() - 1;
584 Class<?> elemType = arrayType.getComponentType();
585 int collected = argc - uncollected;
586 Object collArgs = (elemType == Object.class)
587 ? new Object[collected] : Array.newInstance(elemType, collected);
588 if (!elemType.isPrimitive()) {
589 // simple cast: just do some casting
590 try {
591 System.arraycopy(arguments, uncollected, collArgs, 0, collected);
592 } catch (ArrayStoreException ex) {
593 return super.invokeWithArguments(arguments);
594 }
595 } else {
596 // corner case of flat array requires reflection (or specialized copy loop)
597 MethodHandle arraySetter = MethodHandles.arrayElementSetter(arrayType);
598 try {
599 for (int i = 0; i < collected; i++) {
600 arraySetter.invoke(collArgs, i, arguments[uncollected + i]);
601 }
602 } catch (WrongMethodTypeException|ClassCastException ex) {
603 return super.invokeWithArguments(arguments);
604 }
605 }
606
607 // chop the jumbo list down to size and call in non-varargs mode
608 Object[] newArgs = new Object[uncollected + 1];
609 System.arraycopy(arguments, 0, newArgs, 0, uncollected);
610 newArgs[uncollected] = collArgs;
611 return asFixedArity().invokeWithArguments(newArgs);
612 }
613 }
614
615 /** Factory method: Spread selected argument. */
616 static MethodHandle makeSpreadArguments(MethodHandle target,
617 Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
618 MethodType targetType = target.type();
619
620 for (int i = 0; i < spreadArgCount; i++) {
621 Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i);
622 if (arg == null) arg = Object.class;
623 targetType = targetType.changeParameterType(spreadArgPos + i, arg);
624 }
625 target = target.asType(targetType);
626
627 MethodType srcType = targetType
628 .replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType);
629 // Now build a LambdaForm.
630 MethodType lambdaType = srcType.invokerType();
631 Name[] names = arguments(spreadArgCount + 2, lambdaType);
632 int nameCursor = lambdaType.parameterCount();
633 int[] indexes = new int[targetType.parameterCount()];
634
635 for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) {
636 Class<?> src = lambdaType.parameterType(i);
637 if (i == spreadArgPos) {
638 // Spread the array.
639 MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType);
640 Name array = names[argIndex];
641 names[nameCursor++] = new Name(getFunction(NF_checkSpreadArgument), array, spreadArgCount);
642 for (int j = 0; j < spreadArgCount; i++, j++) {
643 indexes[i] = nameCursor;
644 names[nameCursor++] = new Name(new NamedFunction(aload, Intrinsic.ARRAY_LOAD), array, j);
645 }
646 } else if (i < indexes.length) {
647 indexes[i] = argIndex;
648 }
649 }
650 assert(nameCursor == names.length-1); // leave room for the final call
651
652 // Build argument array for the call.
653 Name[] targetArgs = new Name[targetType.parameterCount()];
654 for (int i = 0; i < targetType.parameterCount(); i++) {
655 int idx = indexes[i];
656 targetArgs[i] = names[idx];
657 }
658 names[names.length - 1] = new Name(target, (Object[]) targetArgs);
659
660 LambdaForm form = new LambdaForm(lambdaType.parameterCount(), names, Kind.SPREAD);
661 return SimpleMethodHandle.make(srcType, form);
662 }
663
664 static void checkSpreadArgument(Object av, int n) {
665 if (av == null && n == 0) {
666 return;
667 } else if (av == null) {
668 throw new NullPointerException("null array reference");
669 } else if (av instanceof Object[]) {
670 int len = ((Object[])av).length;
671 if (len == n) return;
672 } else {
673 int len = java.lang.reflect.Array.getLength(av);
674 if (len == n) return;
675 }
676 // fall through to error:
677 throw newIllegalArgumentException("array is not of length "+n);
678 }
679
680 /** Factory method: Collect or filter selected argument(s). */
681 static MethodHandle makeCollectArguments(MethodHandle target,
682 MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) {
683 MethodType targetType = target.type(); // (a..., c, [b...])=>r
684 MethodType collectorType = collector.type(); // (b...)=>c
685 int collectArgCount = collectorType.parameterCount();
686 Class<?> collectValType = collectorType.returnType();
687 int collectValCount = (collectValType == void.class ? 0 : 1);
688 MethodType srcType = targetType // (a..., [b...])=>r
689 .dropParameterTypes(collectArgPos, collectArgPos+collectValCount);
690 if (!retainOriginalArgs) { // (a..., b...)=>r
691 srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterArray());
692 }
693 // in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ]
694 // out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ]
695 // out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ]
696
697 // Now build a LambdaForm.
698 MethodType lambdaType = srcType.invokerType();
699 Name[] names = arguments(2, lambdaType);
700 final int collectNamePos = names.length - 2;
701 final int targetNamePos = names.length - 1;
702
703 Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount);
704 names[collectNamePos] = new Name(collector, (Object[]) collectorArgs);
705
706 // Build argument array for the target.
707 // Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ].
708 // Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ].
709 Name[] targetArgs = new Name[targetType.parameterCount()];
710 int inputArgPos = 1; // incoming LF args to copy to target
711 int targetArgPos = 0; // fill pointer for targetArgs
712 int chunk = collectArgPos; // |headArgs|
713 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
714 inputArgPos += chunk;
715 targetArgPos += chunk;
716 if (collectValType != void.class) {
717 targetArgs[targetArgPos++] = names[collectNamePos];
718 }
719 chunk = collectArgCount;
720 if (retainOriginalArgs) {
721 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
722 targetArgPos += chunk; // optionally pass on the collected chunk
723 }
724 inputArgPos += chunk;
725 chunk = targetArgs.length - targetArgPos; // all the rest
726 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
727 assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also
728 names[targetNamePos] = new Name(target, (Object[]) targetArgs);
729
730 LambdaForm form = new LambdaForm(lambdaType.parameterCount(), names, Kind.COLLECT);
731 return SimpleMethodHandle.make(srcType, form);
732 }
733
734 @LambdaForm.Hidden
735 static
736 MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
737 if (testResult) {
738 return target;
739 } else {
740 return fallback;
741 }
742 }
743
744 // Intrinsified by C2. Counters are used during parsing to calculate branch frequencies.
745 @LambdaForm.Hidden
746 @jdk.internal.HotSpotIntrinsicCandidate
747 static
748 boolean profileBoolean(boolean result, int[] counters) {
749 // Profile is int[2] where [0] and [1] correspond to false and true occurrences respectively.
750 int idx = result ? 1 : 0;
751 try {
752 counters[idx] = Math.addExact(counters[idx], 1);
753 } catch (ArithmeticException e) {
754 // Avoid continuous overflow by halving the problematic count.
755 counters[idx] = counters[idx] / 2;
756 }
757 return result;
758 }
759
760 // Intrinsified by C2. Returns true if obj is a compile-time constant.
761 @LambdaForm.Hidden
762 @jdk.internal.HotSpotIntrinsicCandidate
763 static
764 boolean isCompileConstant(Object obj) {
765 return false;
766 }
767
768 static
769 MethodHandle makeGuardWithTest(MethodHandle test,
770 MethodHandle target,
771 MethodHandle fallback) {
772 MethodType type = target.type();
773 assert(test.type().equals(type.changeReturnType(boolean.class)) && fallback.type().equals(type));
774 MethodType basicType = type.basicType();
775 LambdaForm form = makeGuardWithTestForm(basicType);
776 BoundMethodHandle mh;
777 try {
778 if (PROFILE_GWT) {
779 int[] counts = new int[2];
780 mh = (BoundMethodHandle)
781 BoundMethodHandle.speciesData_LLLL().factory().invokeBasic(type, form,
782 (Object) test, (Object) profile(target), (Object) profile(fallback), counts);
783 } else {
784 mh = (BoundMethodHandle)
785 BoundMethodHandle.speciesData_LLL().factory().invokeBasic(type, form,
786 (Object) test, (Object) profile(target), (Object) profile(fallback));
787 }
788 } catch (Throwable ex) {
789 throw uncaughtException(ex);
790 }
791 assert(mh.type() == type);
792 return mh;
793 }
794
795
796 static
797 MethodHandle profile(MethodHandle target) {
798 if (DONT_INLINE_THRESHOLD >= 0) {
799 return makeBlockInliningWrapper(target);
800 } else {
801 return target;
802 }
803 }
804
805 /**
806 * Block inlining during JIT-compilation of a target method handle if it hasn't been invoked enough times.
807 * Corresponding LambdaForm has @DontInline when compiled into bytecode.
808 */
809 static
810 MethodHandle makeBlockInliningWrapper(MethodHandle target) {
811 LambdaForm lform;
812 if (DONT_INLINE_THRESHOLD > 0) {
813 lform = Makers.PRODUCE_BLOCK_INLINING_FORM.apply(target);
814 } else {
815 lform = Makers.PRODUCE_REINVOKER_FORM.apply(target);
816 }
817 return new CountingWrapper(target, lform,
818 Makers.PRODUCE_BLOCK_INLINING_FORM, Makers.PRODUCE_REINVOKER_FORM,
819 DONT_INLINE_THRESHOLD);
820 }
821
822 private final static class Makers {
823 /** Constructs reinvoker lambda form which block inlining during JIT-compilation for a particular method handle */
824 static final Function<MethodHandle, LambdaForm> PRODUCE_BLOCK_INLINING_FORM = new Function<MethodHandle, LambdaForm>() {
825 @Override
826 public LambdaForm apply(MethodHandle target) {
827 return DelegatingMethodHandle.makeReinvokerForm(target,
828 MethodTypeForm.LF_DELEGATE_BLOCK_INLINING, CountingWrapper.class, false,
829 DelegatingMethodHandle.NF_getTarget, CountingWrapper.NF_maybeStopCounting);
830 }
831 };
832
833 /** Constructs simple reinvoker lambda form for a particular method handle */
834 static final Function<MethodHandle, LambdaForm> PRODUCE_REINVOKER_FORM = new Function<MethodHandle, LambdaForm>() {
835 @Override
836 public LambdaForm apply(MethodHandle target) {
837 return DelegatingMethodHandle.makeReinvokerForm(target,
838 MethodTypeForm.LF_DELEGATE, DelegatingMethodHandle.class, DelegatingMethodHandle.NF_getTarget);
839 }
840 };
841
842 /** Maker of type-polymorphic varargs */
843 static final ClassValue<MethodHandle[]> TYPED_COLLECTORS = new ClassValue<MethodHandle[]>() {
844 @Override
845 protected MethodHandle[] computeValue(Class<?> type) {
846 return new MethodHandle[MAX_JVM_ARITY + 1];
847 }
848 };
849 }
850
851 /**
852 * Counting method handle. It has 2 states: counting and non-counting.
853 * It is in counting state for the first n invocations and then transitions to non-counting state.
854 * Behavior in counting and non-counting states is determined by lambda forms produced by
855 * countingFormProducer & nonCountingFormProducer respectively.
856 */
857 static class CountingWrapper extends DelegatingMethodHandle {
858 private final MethodHandle target;
859 private int count;
860 private Function<MethodHandle, LambdaForm> countingFormProducer;
861 private Function<MethodHandle, LambdaForm> nonCountingFormProducer;
862 private volatile boolean isCounting;
863
864 private CountingWrapper(MethodHandle target, LambdaForm lform,
865 Function<MethodHandle, LambdaForm> countingFromProducer,
866 Function<MethodHandle, LambdaForm> nonCountingFormProducer,
867 int count) {
868 super(target.type(), lform);
869 this.target = target;
870 this.count = count;
871 this.countingFormProducer = countingFromProducer;
872 this.nonCountingFormProducer = nonCountingFormProducer;
873 this.isCounting = (count > 0);
874 }
875
876 @Hidden
877 @Override
878 protected MethodHandle getTarget() {
879 return target;
880 }
881
882 @Override
883 public MethodHandle asTypeUncached(MethodType newType) {
884 MethodHandle newTarget = target.asType(newType);
885 MethodHandle wrapper;
886 if (isCounting) {
887 LambdaForm lform;
888 lform = countingFormProducer.apply(newTarget);
889 wrapper = new CountingWrapper(newTarget, lform, countingFormProducer, nonCountingFormProducer, DONT_INLINE_THRESHOLD);
890 } else {
891 wrapper = newTarget; // no need for a counting wrapper anymore
892 }
893 return (asTypeCache = wrapper);
894 }
895
896 // Customize target if counting happens for too long.
897 private int invocations = CUSTOMIZE_THRESHOLD;
898 private void maybeCustomizeTarget() {
899 int c = invocations;
900 if (c >= 0) {
901 if (c == 1) {
902 target.customize();
903 }
904 invocations = c - 1;
905 }
906 }
907
908 boolean countDown() {
909 int c = count;
910 maybeCustomizeTarget();
911 if (c <= 1) {
912 // Try to limit number of updates. MethodHandle.updateForm() doesn't guarantee LF update visibility.
913 if (isCounting) {
914 isCounting = false;
915 return true;
916 } else {
917 return false;
918 }
919 } else {
920 count = c - 1;
921 return false;
922 }
923 }
924
925 @Hidden
926 static void maybeStopCounting(Object o1) {
927 CountingWrapper wrapper = (CountingWrapper) o1;
928 if (wrapper.countDown()) {
929 // Reached invocation threshold. Replace counting behavior with a non-counting one.
930 LambdaForm lform = wrapper.nonCountingFormProducer.apply(wrapper.target);
931 lform.compileToBytecode(); // speed up warmup by avoiding LF interpretation again after transition
932 wrapper.updateForm(lform);
933 }
934 }
935
936 static final NamedFunction NF_maybeStopCounting;
937 static {
938 Class<?> THIS_CLASS = CountingWrapper.class;
939 try {
940 NF_maybeStopCounting = new NamedFunction(THIS_CLASS.getDeclaredMethod("maybeStopCounting", Object.class));
941 } catch (ReflectiveOperationException ex) {
942 throw newInternalError(ex);
943 }
944 }
945 }
946
947 static
948 LambdaForm makeGuardWithTestForm(MethodType basicType) {
949 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWT);
950 if (lform != null) return lform;
951 final int THIS_MH = 0; // the BMH_LLL
952 final int ARG_BASE = 1; // start of incoming arguments
953 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
954 int nameCursor = ARG_LIMIT;
955 final int GET_TEST = nameCursor++;
956 final int GET_TARGET = nameCursor++;
957 final int GET_FALLBACK = nameCursor++;
958 final int GET_COUNTERS = PROFILE_GWT ? nameCursor++ : -1;
959 final int CALL_TEST = nameCursor++;
960 final int PROFILE = (GET_COUNTERS != -1) ? nameCursor++ : -1;
961 final int TEST = nameCursor-1; // previous statement: either PROFILE or CALL_TEST
962 final int SELECT_ALT = nameCursor++;
963 final int CALL_TARGET = nameCursor++;
964 assert(CALL_TARGET == SELECT_ALT+1); // must be true to trigger IBG.emitSelectAlternative
965
966 MethodType lambdaType = basicType.invokerType();
967 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
968
969 BoundMethodHandle.SpeciesData data =
970 (GET_COUNTERS != -1) ? BoundMethodHandle.speciesData_LLLL()
971 : BoundMethodHandle.speciesData_LLL();
972 names[THIS_MH] = names[THIS_MH].withConstraint(data);
973 names[GET_TEST] = new Name(data.getterFunction(0), names[THIS_MH]);
974 names[GET_TARGET] = new Name(data.getterFunction(1), names[THIS_MH]);
975 names[GET_FALLBACK] = new Name(data.getterFunction(2), names[THIS_MH]);
976 if (GET_COUNTERS != -1) {
977 names[GET_COUNTERS] = new Name(data.getterFunction(3), names[THIS_MH]);
978 }
979 Object[] invokeArgs = Arrays.copyOfRange(names, 0, ARG_LIMIT, Object[].class);
980
981 // call test
982 MethodType testType = basicType.changeReturnType(boolean.class).basicType();
983 invokeArgs[0] = names[GET_TEST];
984 names[CALL_TEST] = new Name(testType, invokeArgs);
985
986 // profile branch
987 if (PROFILE != -1) {
988 names[PROFILE] = new Name(getFunction(NF_profileBoolean), names[CALL_TEST], names[GET_COUNTERS]);
989 }
990 // call selectAlternative
991 names[SELECT_ALT] = new Name(new NamedFunction(getConstantHandle(MH_selectAlternative), Intrinsic.SELECT_ALTERNATIVE), names[TEST], names[GET_TARGET], names[GET_FALLBACK]);
992
993 // call target or fallback
994 invokeArgs[0] = names[SELECT_ALT];
995 names[CALL_TARGET] = new Name(basicType, invokeArgs);
996
997 lform = new LambdaForm(lambdaType.parameterCount(), names, /*forceInline=*/true, Kind.GUARD);
998
999 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWT, lform);
1000 }
1001
1002 /**
1003 * The LambdaForm shape for catchException combinator is the following:
1004 * <blockquote><pre>{@code
1005 * guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{
1006 * t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L);
1007 * t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L);
1008 * t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L);
1009 * t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L);
1010 * t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L);
1011 * t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L);
1012 * t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L);
1013 * t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I}
1014 * }</pre></blockquote>
1015 *
1016 * argL0 and argL2 are target and catcher method handles. argL1 is exception class.
1017 * argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[]
1018 * (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()).
1019 *
1020 * Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms
1021 * among catchException combinators with the same basic type.
1022 */
1023 private static LambdaForm makeGuardWithCatchForm(MethodType basicType) {
1024 MethodType lambdaType = basicType.invokerType();
1025
1026 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC);
1027 if (lform != null) {
1028 return lform;
1029 }
1030 final int THIS_MH = 0; // the BMH_LLLLL
1031 final int ARG_BASE = 1; // start of incoming arguments
1032 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
1033
1034 int nameCursor = ARG_LIMIT;
1035 final int GET_TARGET = nameCursor++;
1036 final int GET_CLASS = nameCursor++;
1037 final int GET_CATCHER = nameCursor++;
1038 final int GET_COLLECT_ARGS = nameCursor++;
1039 final int GET_UNBOX_RESULT = nameCursor++;
1040 final int BOXED_ARGS = nameCursor++;
1041 final int TRY_CATCH = nameCursor++;
1042 final int UNBOX_RESULT = nameCursor++;
1043
1044 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
1045
1046 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
1047 names[THIS_MH] = names[THIS_MH].withConstraint(data);
1048 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
1049 names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]);
1050 names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]);
1051 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]);
1052 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]);
1053
1054 // FIXME: rework argument boxing/result unboxing logic for LF interpretation
1055
1056 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
1057 MethodType collectArgsType = basicType.changeReturnType(Object.class);
1058 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
1059 Object[] args = new Object[invokeBasic.type().parameterCount()];
1060 args[0] = names[GET_COLLECT_ARGS];
1061 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
1062 names[BOXED_ARGS] = new Name(new NamedFunction(invokeBasic, Intrinsic.GUARD_WITH_CATCH), args);
1063
1064 // t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L);
1065 Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]};
1066 names[TRY_CATCH] = new Name(getFunction(NF_guardWithCatch), gwcArgs);
1067
1068 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
1069 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
1070 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]};
1071 names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
1072
1073 lform = new LambdaForm(lambdaType.parameterCount(), names, Kind.GUARD_WITH_CATCH);
1074
1075 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform);
1076 }
1077
1078 static
1079 MethodHandle makeGuardWithCatch(MethodHandle target,
1080 Class<? extends Throwable> exType,
1081 MethodHandle catcher) {
1082 MethodType type = target.type();
1083 LambdaForm form = makeGuardWithCatchForm(type.basicType());
1084
1085 // Prepare auxiliary method handles used during LambdaForm interpretation.
1086 // Box arguments and wrap them into Object[]: ValueConversions.array().
1087 MethodType varargsType = type.changeReturnType(Object[].class);
1088 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
1089 MethodHandle unboxResult = unboxResultHandle(type.returnType());
1090
1091 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
1092 BoundMethodHandle mh;
1093 try {
1094 mh = (BoundMethodHandle) data.factory().invokeBasic(type, form, (Object) target, (Object) exType,
1095 (Object) catcher, (Object) collectArgs, (Object) unboxResult);
1096 } catch (Throwable ex) {
1097 throw uncaughtException(ex);
1098 }
1099 assert(mh.type() == type);
1100 return mh;
1101 }
1102
1103 /**
1104 * Intrinsified during LambdaForm compilation
1105 * (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}).
1106 */
1107 @LambdaForm.Hidden
1108 static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher,
1109 Object... av) throws Throwable {
1110 // Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case.
1111 try {
1112 return target.asFixedArity().invokeWithArguments(av);
1113 } catch (Throwable t) {
1114 if (!exType.isInstance(t)) throw t;
1115 return catcher.asFixedArity().invokeWithArguments(prepend(av, t));
1116 }
1117 }
1118
1119 /** Prepend elements to an array. */
1120 @LambdaForm.Hidden
1121 private static Object[] prepend(Object[] array, Object... elems) {
1122 int nArray = array.length;
1123 int nElems = elems.length;
1124 Object[] newArray = new Object[nArray + nElems];
1125 System.arraycopy(elems, 0, newArray, 0, nElems);
1126 System.arraycopy(array, 0, newArray, nElems, nArray);
1127 return newArray;
1128 }
1129
1130 static
1131 MethodHandle throwException(MethodType type) {
1132 assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
1133 int arity = type.parameterCount();
1134 if (arity > 1) {
1135 MethodHandle mh = throwException(type.dropParameterTypes(1, arity));
1136 mh = MethodHandles.dropArguments(mh, 1, Arrays.copyOfRange(type.parameterArray(), 1, arity));
1137 return mh;
1138 }
1139 return makePairwiseConvert(getFunction(NF_throwException).resolvedHandle(), type, false, true);
1140 }
1141
1142 static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
1143
1144 static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
1145 static MethodHandle fakeMethodHandleInvoke(MemberName method) {
1146 int idx;
1147 assert(method.isMethodHandleInvoke());
1148 switch (method.getName()) {
1149 case "invoke": idx = 0; break;
1150 case "invokeExact": idx = 1; break;
1151 default: throw new InternalError(method.getName());
1152 }
1153 MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
1154 if (mh != null) return mh;
1155 MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
1156 MethodHandle.class, Object[].class);
1157 mh = throwException(type);
1158 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
1159 if (!method.getInvocationType().equals(mh.type()))
1160 throw new InternalError(method.toString());
1161 mh = mh.withInternalMemberName(method, false);
1162 mh = mh.withVarargs(true);
1163 assert(method.isVarargs());
1164 FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
1165 return mh;
1166 }
1167 static MethodHandle fakeVarHandleInvoke(MemberName method) {
1168 // TODO caching, is it necessary?
1169 MethodType type = MethodType.methodType(method.getReturnType(), UnsupportedOperationException.class,
1170 VarHandle.class, Object[].class);
1171 MethodHandle mh = throwException(type);
1172 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke VarHandle"));
1173 if (!method.getInvocationType().equals(mh.type()))
1174 throw new InternalError(method.toString());
1175 mh = mh.withInternalMemberName(method, false);
1176 mh = mh.asVarargsCollector(Object[].class);
1177 assert(method.isVarargs());
1178 return mh;
1179 }
1180
1181 /**
1182 * Create an alias for the method handle which, when called,
1183 * appears to be called from the same class loader and protection domain
1184 * as hostClass.
1185 * This is an expensive no-op unless the method which is called
1186 * is sensitive to its caller. A small number of system methods
1187 * are in this category, including Class.forName and Method.invoke.
1188 */
1189 static
1190 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1191 return BindCaller.bindCaller(mh, hostClass);
1192 }
1193
1194 // Put the whole mess into its own nested class.
1195 // That way we can lazily load the code and set up the constants.
1196 private static class BindCaller {
1197 private static MethodType INVOKER_MT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1198
1199 static
1200 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
1201 // Code in the boot layer should now be careful while creating method handles or
1202 // functional interface instances created from method references to @CallerSensitive methods,
1203 // it needs to be ensured the handles or interface instances are kept safe and are not passed
1204 // from the boot layer to untrusted code.
1205 if (hostClass == null
1206 || (hostClass.isArray() ||
1207 hostClass.isPrimitive() ||
1208 hostClass.getName().startsWith("java.lang.invoke."))) {
1209 throw new InternalError(); // does not happen, and should not anyway
1210 }
1211 // For simplicity, convert mh to a varargs-like method.
1212 MethodHandle vamh = prepareForInvoker(mh);
1213 // Cache the result of makeInjectedInvoker once per argument class.
1214 MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
1215 return restoreToType(bccInvoker.bindTo(vamh), mh, hostClass);
1216 }
1217
1218 private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
1219 try {
1220 Class<?> invokerClass = UNSAFE.defineAnonymousClass(hostClass, INJECTED_INVOKER_TEMPLATE, null);
1221 assert checkInjectedInvoker(hostClass, invokerClass);
1222 return IMPL_LOOKUP.findStatic(invokerClass, "invoke_V", INVOKER_MT);
1223 } catch (ReflectiveOperationException ex) {
1224 throw uncaughtException(ex);
1225 }
1226 }
1227
1228 private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() {
1229 @Override protected MethodHandle computeValue(Class<?> hostClass) {
1230 return makeInjectedInvoker(hostClass);
1231 }
1232 };
1233
1234 // Adapt mh so that it can be called directly from an injected invoker:
1235 private static MethodHandle prepareForInvoker(MethodHandle mh) {
1236 mh = mh.asFixedArity();
1237 MethodType mt = mh.type();
1238 int arity = mt.parameterCount();
1239 MethodHandle vamh = mh.asType(mt.generic());
1240 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1241 vamh = vamh.asSpreader(Object[].class, arity);
1242 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
1243 return vamh;
1244 }
1245
1246 // Undo the adapter effect of prepareForInvoker:
1247 private static MethodHandle restoreToType(MethodHandle vamh,
1248 MethodHandle original,
1249 Class<?> hostClass) {
1250 MethodType type = original.type();
1251 MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount());
1252 MemberName member = original.internalMemberName();
1253 mh = mh.asType(type);
1254 mh = new WrappedMember(mh, type, member, original.isInvokeSpecial(), hostClass);
1255 return mh;
1256 }
1257
1258 private static boolean checkInjectedInvoker(Class<?> hostClass, Class<?> invokerClass) {
1259 assert (hostClass.getClassLoader() == invokerClass.getClassLoader()) : hostClass.getName()+" (CL)";
1260 try {
1261 assert (hostClass.getProtectionDomain() == invokerClass.getProtectionDomain()) : hostClass.getName()+" (PD)";
1262 } catch (SecurityException ex) {
1263 // Self-check was blocked by security manager. This is OK.
1264 }
1265 try {
1266 // Test the invoker to ensure that it really injects into the right place.
1267 MethodHandle invoker = IMPL_LOOKUP.findStatic(invokerClass, "invoke_V", INVOKER_MT);
1268 MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
1269 return (boolean)invoker.invoke(vamh, new Object[]{ invokerClass });
1270 } catch (Throwable ex) {
1271 throw new InternalError(ex);
1272 }
1273 }
1274
1275 private static final MethodHandle MH_checkCallerClass;
1276 static {
1277 final Class<?> THIS_CLASS = BindCaller.class;
1278 assert(checkCallerClass(THIS_CLASS));
1279 try {
1280 MH_checkCallerClass = IMPL_LOOKUP
1281 .findStatic(THIS_CLASS, "checkCallerClass",
1282 MethodType.methodType(boolean.class, Class.class));
1283 assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS));
1284 } catch (Throwable ex) {
1285 throw new InternalError(ex);
1286 }
1287 }
1288
1289 @CallerSensitive
1290 @ForceInline // to ensure Reflection.getCallerClass optimization
1291 private static boolean checkCallerClass(Class<?> expected) {
1292 // This method is called via MH_checkCallerClass and so it's correct to ask for the immediate caller here.
1293 Class<?> actual = Reflection.getCallerClass();
1294 if (actual != expected)
1295 throw new InternalError("found " + actual.getName() + ", expected " + expected.getName());
1296 return true;
1297 }
1298
1299 private static final byte[] INJECTED_INVOKER_TEMPLATE = generateInvokerTemplate();
1300
1301 /** Produces byte code for a class that is used as an injected invoker. */
1302 private static byte[] generateInvokerTemplate() {
1303 ClassWriter cw = new ClassWriter(0);
1304
1305 // private static class InjectedInvoker {
1306 // @Hidden
1307 // static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
1308 // return vamh.invokeExact(args);
1309 // }
1310 // }
1311 cw.visit(52, ACC_PRIVATE | ACC_SUPER, "InjectedInvoker", null, "java/lang/Object", null);
1312
1313 MethodVisitor mv = cw.visitMethod(ACC_STATIC, "invoke_V",
1314 "(Ljava/lang/invoke/MethodHandle;[Ljava/lang/Object;)Ljava/lang/Object;",
1315 null, null);
1316
1317 // Suppress invoker method in stack traces.
1318 AnnotationVisitor av0 = mv.visitAnnotation("Ljava/lang/invoke/LambdaForm$Hidden;", true);
1319 av0.visitEnd();
1320
1321 mv.visitCode();
1322 mv.visitVarInsn(ALOAD, 0);
1323 mv.visitVarInsn(ALOAD, 1);
1324 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/invoke/MethodHandle", "invokeExact",
1325 "([Ljava/lang/Object;)Ljava/lang/Object;", false);
1326 mv.visitInsn(ARETURN);
1327 mv.visitMaxs(2, 2);
1328 mv.visitEnd();
1329
1330 cw.visitEnd();
1331 return cw.toByteArray();
1332 }
1333 }
1334
1335 /** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */
1336 private static final class WrappedMember extends DelegatingMethodHandle {
1337 private final MethodHandle target;
1338 private final MemberName member;
1339 private final Class<?> callerClass;
1340 private final boolean isInvokeSpecial;
1341
1342 private WrappedMember(MethodHandle target, MethodType type,
1343 MemberName member, boolean isInvokeSpecial,
1344 Class<?> callerClass) {
1345 super(type, target);
1346 this.target = target;
1347 this.member = member;
1348 this.callerClass = callerClass;
1349 this.isInvokeSpecial = isInvokeSpecial;
1350 }
1351
1352 @Override
1353 MemberName internalMemberName() {
1354 return member;
1355 }
1356 @Override
1357 Class<?> internalCallerClass() {
1358 return callerClass;
1359 }
1360 @Override
1361 boolean isInvokeSpecial() {
1362 return isInvokeSpecial;
1363 }
1364 @Override
1365 protected MethodHandle getTarget() {
1366 return target;
1367 }
1368 @Override
1369 public MethodHandle asTypeUncached(MethodType newType) {
1370 // This MH is an alias for target, except for the MemberName
1371 // Drop the MemberName if there is any conversion.
1372 return asTypeCache = target.asType(newType);
1373 }
1374 }
1375
1376 static MethodHandle makeWrappedMember(MethodHandle target, MemberName member, boolean isInvokeSpecial) {
1377 if (member.equals(target.internalMemberName()) && isInvokeSpecial == target.isInvokeSpecial())
1378 return target;
1379 return new WrappedMember(target, target.type(), member, isInvokeSpecial, null);
1380 }
1381
1382 /** Intrinsic IDs */
1383 /*non-public*/
1384 enum Intrinsic {
1385 SELECT_ALTERNATIVE,
1386 GUARD_WITH_CATCH,
1387 TRY_FINALLY,
1388 LOOP,
1389 NEW_ARRAY,
1390 ARRAY_LOAD,
1391 ARRAY_STORE,
1392 ARRAY_LENGTH,
1393 IDENTITY,
1394 ZERO,
1395 NONE // no intrinsic associated
1396 }
1397
1398 /** Mark arbitrary method handle as intrinsic.
1399 * InvokerBytecodeGenerator uses this info to produce more efficient bytecode shape. */
1400 static final class IntrinsicMethodHandle extends DelegatingMethodHandle {
1401 private final MethodHandle target;
1402 private final Intrinsic intrinsicName;
1403
1404 IntrinsicMethodHandle(MethodHandle target, Intrinsic intrinsicName) {
1405 super(target.type(), target);
1406 this.target = target;
1407 this.intrinsicName = intrinsicName;
1408 }
1409
1410 @Override
1411 protected MethodHandle getTarget() {
1412 return target;
1413 }
1414
1415 @Override
1416 Intrinsic intrinsicName() {
1417 return intrinsicName;
1418 }
1419
1420 @Override
1421 public MethodHandle asTypeUncached(MethodType newType) {
1422 // This MH is an alias for target, except for the intrinsic name
1423 // Drop the name if there is any conversion.
1424 return asTypeCache = target.asType(newType);
1425 }
1426
1427 @Override
1428 String internalProperties() {
1429 return super.internalProperties() +
1430 "\n& Intrinsic="+intrinsicName;
1431 }
1432
1433 @Override
1434 public MethodHandle asCollector(Class<?> arrayType, int arrayLength) {
1435 if (intrinsicName == Intrinsic.IDENTITY) {
1436 MethodType resultType = type().asCollectorType(arrayType, type().parameterCount() - 1, arrayLength);
1437 MethodHandle newArray = MethodHandleImpl.varargsArray(arrayType, arrayLength);
1438 return newArray.asType(resultType);
1439 }
1440 return super.asCollector(arrayType, arrayLength);
1441 }
1442 }
1443
1444 static MethodHandle makeIntrinsic(MethodHandle target, Intrinsic intrinsicName) {
1445 if (intrinsicName == target.intrinsicName())
1446 return target;
1447 return new IntrinsicMethodHandle(target, intrinsicName);
1448 }
1449
1450 static MethodHandle makeIntrinsic(MethodType type, LambdaForm form, Intrinsic intrinsicName) {
1451 return new IntrinsicMethodHandle(SimpleMethodHandle.make(type, form), intrinsicName);
1452 }
1453
1454 /// Collection of multiple arguments.
1455
1456 private static MethodHandle findCollector(String name, int nargs, Class<?> rtype, Class<?>... ptypes) {
1457 MethodType type = MethodType.genericMethodType(nargs)
1458 .changeReturnType(rtype)
1459 .insertParameterTypes(0, ptypes);
1460 try {
1461 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, name, type);
1462 } catch (ReflectiveOperationException ex) {
1463 return null;
1464 }
1465 }
1466
1467 private static final Object[] NO_ARGS_ARRAY = {};
1468 private static Object[] makeArray(Object... args) { return args; }
1469 private static Object[] array() { return NO_ARGS_ARRAY; }
1470 private static Object[] array(Object a0)
1471 { return makeArray(a0); }
1472 private static Object[] array(Object a0, Object a1)
1473 { return makeArray(a0, a1); }
1474 private static Object[] array(Object a0, Object a1, Object a2)
1475 { return makeArray(a0, a1, a2); }
1476 private static Object[] array(Object a0, Object a1, Object a2, Object a3)
1477 { return makeArray(a0, a1, a2, a3); }
1478 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1479 Object a4)
1480 { return makeArray(a0, a1, a2, a3, a4); }
1481 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1482 Object a4, Object a5)
1483 { return makeArray(a0, a1, a2, a3, a4, a5); }
1484 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1485 Object a4, Object a5, Object a6)
1486 { return makeArray(a0, a1, a2, a3, a4, a5, a6); }
1487 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1488 Object a4, Object a5, Object a6, Object a7)
1489 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7); }
1490 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1491 Object a4, Object a5, Object a6, Object a7,
1492 Object a8)
1493 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8); }
1494 private static Object[] array(Object a0, Object a1, Object a2, Object a3,
1495 Object a4, Object a5, Object a6, Object a7,
1496 Object a8, Object a9)
1497 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
1498
1499 private static final int ARRAYS_COUNT = 11;
1500 private static final @Stable MethodHandle[] ARRAYS = new MethodHandle[MAX_ARITY + 1];
1501
1502 // filling versions of the above:
1503 // using Integer len instead of int len and no varargs to avoid bootstrapping problems
1504 private static Object[] fillNewArray(Integer len, Object[] /*not ...*/ args) {
1505 Object[] a = new Object[len];
1506 fillWithArguments(a, 0, args);
1507 return a;
1508 }
1509 private static Object[] fillNewTypedArray(Object[] example, Integer len, Object[] /*not ...*/ args) {
1510 Object[] a = Arrays.copyOf(example, len);
1511 assert(a.getClass() != Object[].class);
1512 fillWithArguments(a, 0, args);
1513 return a;
1514 }
1515 private static void fillWithArguments(Object[] a, int pos, Object... args) {
1516 System.arraycopy(args, 0, a, pos, args.length);
1517 }
1518 // using Integer pos instead of int pos to avoid bootstrapping problems
1519 private static Object[] fillArray(Integer pos, Object[] a, Object a0)
1520 { fillWithArguments(a, pos, a0); return a; }
1521 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1)
1522 { fillWithArguments(a, pos, a0, a1); return a; }
1523 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2)
1524 { fillWithArguments(a, pos, a0, a1, a2); return a; }
1525 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3)
1526 { fillWithArguments(a, pos, a0, a1, a2, a3); return a; }
1527 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1528 Object a4)
1529 { fillWithArguments(a, pos, a0, a1, a2, a3, a4); return a; }
1530 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1531 Object a4, Object a5)
1532 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5); return a; }
1533 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1534 Object a4, Object a5, Object a6)
1535 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6); return a; }
1536 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1537 Object a4, Object a5, Object a6, Object a7)
1538 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7); return a; }
1539 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1540 Object a4, Object a5, Object a6, Object a7,
1541 Object a8)
1542 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8); return a; }
1543 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
1544 Object a4, Object a5, Object a6, Object a7,
1545 Object a8, Object a9)
1546 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); return a; }
1547
1548 private static final int FILL_ARRAYS_COUNT = 11; // current number of fillArray methods
1549 private static final @Stable MethodHandle[] FILL_ARRAYS = new MethodHandle[FILL_ARRAYS_COUNT];
1550
1551 private static MethodHandle getFillArray(int count) {
1552 assert (count > 0 && count < FILL_ARRAYS_COUNT);
1553 MethodHandle mh = FILL_ARRAYS[count];
1554 if (mh != null) {
1555 return mh;
1556 }
1557 mh = findCollector("fillArray", count, Object[].class, Integer.class, Object[].class);
1558 FILL_ARRAYS[count] = mh;
1559 return mh;
1560 }
1561
1562 private static Object copyAsPrimitiveArray(Wrapper w, Object... boxes) {
1563 Object a = w.makeArray(boxes.length);
1564 w.copyArrayUnboxing(boxes, 0, a, 0, boxes.length);
1565 return a;
1566 }
1567
1568 /** Return a method handle that takes the indicated number of Object
1569 * arguments and returns an Object array of them, as if for varargs.
1570 */
1571 static MethodHandle varargsArray(int nargs) {
1572 MethodHandle mh = ARRAYS[nargs];
1573 if (mh != null) {
1574 return mh;
1575 }
1576 if (nargs < ARRAYS_COUNT) {
1577 mh = findCollector("array", nargs, Object[].class);
1578 } else {
1579 mh = buildVarargsArray(getConstantHandle(MH_fillNewArray),
1580 getConstantHandle(MH_arrayIdentity), nargs);
1581 }
1582 assert(assertCorrectArity(mh, nargs));
1583 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1584 return ARRAYS[nargs] = mh;
1585 }
1586
1587 private static boolean assertCorrectArity(MethodHandle mh, int arity) {
1588 assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh;
1589 return true;
1590 }
1591
1592 // Array identity function (used as getConstantHandle(MH_arrayIdentity)).
1593 static <T> T[] identity(T[] x) {
1594 return x;
1595 }
1596
1597 private static MethodHandle buildVarargsArray(MethodHandle newArray, MethodHandle finisher, int nargs) {
1598 // Build up the result mh as a sequence of fills like this:
1599 // finisher(fill(fill(newArrayWA(23,x1..x10),10,x11..x20),20,x21..x23))
1600 // The various fill(_,10*I,___*[J]) are reusable.
1601 int leftLen = Math.min(nargs, LEFT_ARGS); // absorb some arguments immediately
1602 int rightLen = nargs - leftLen;
1603 MethodHandle leftCollector = newArray.bindTo(nargs);
1604 leftCollector = leftCollector.asCollector(Object[].class, leftLen);
1605 MethodHandle mh = finisher;
1606 if (rightLen > 0) {
1607 MethodHandle rightFiller = fillToRight(LEFT_ARGS + rightLen);
1608 if (mh.equals(getConstantHandle(MH_arrayIdentity)))
1609 mh = rightFiller;
1610 else
1611 mh = MethodHandles.collectArguments(mh, 0, rightFiller);
1612 }
1613 if (mh.equals(getConstantHandle(MH_arrayIdentity)))
1614 mh = leftCollector;
1615 else
1616 mh = MethodHandles.collectArguments(mh, 0, leftCollector);
1617 return mh;
1618 }
1619
1620 private static final int LEFT_ARGS = FILL_ARRAYS_COUNT - 1;
1621 private static final @Stable MethodHandle[] FILL_ARRAY_TO_RIGHT = new MethodHandle[MAX_ARITY + 1];
1622 /** fill_array_to_right(N).invoke(a, argL..arg[N-1])
1623 * fills a[L]..a[N-1] with corresponding arguments,
1624 * and then returns a. The value L is a global constant (LEFT_ARGS).
1625 */
1626 private static MethodHandle fillToRight(int nargs) {
1627 MethodHandle filler = FILL_ARRAY_TO_RIGHT[nargs];
1628 if (filler != null) return filler;
1629 filler = buildFiller(nargs);
1630 assert(assertCorrectArity(filler, nargs - LEFT_ARGS + 1));
1631 return FILL_ARRAY_TO_RIGHT[nargs] = filler;
1632 }
1633 private static MethodHandle buildFiller(int nargs) {
1634 if (nargs <= LEFT_ARGS)
1635 return getConstantHandle(MH_arrayIdentity); // no args to fill; return the array unchanged
1636 // we need room for both mh and a in mh.invoke(a, arg*[nargs])
1637 final int CHUNK = LEFT_ARGS;
1638 int rightLen = nargs % CHUNK;
1639 int midLen = nargs - rightLen;
1640 if (rightLen == 0) {
1641 midLen = nargs - (rightLen = CHUNK);
1642 if (FILL_ARRAY_TO_RIGHT[midLen] == null) {
1643 // build some precursors from left to right
1644 for (int j = LEFT_ARGS % CHUNK; j < midLen; j += CHUNK)
1645 if (j > LEFT_ARGS) fillToRight(j);
1646 }
1647 }
1648 if (midLen < LEFT_ARGS) rightLen = nargs - (midLen = LEFT_ARGS);
1649 assert(rightLen > 0);
1650 MethodHandle midFill = fillToRight(midLen); // recursive fill
1651 MethodHandle rightFill = getFillArray(rightLen).bindTo(midLen); // [midLen..nargs-1]
1652 assert(midFill.type().parameterCount() == 1 + midLen - LEFT_ARGS);
1653 assert(rightFill.type().parameterCount() == 1 + rightLen);
1654
1655 // Combine the two fills:
1656 // right(mid(a, x10..x19), x20..x23)
1657 // The final product will look like this:
1658 // right(mid(newArrayLeft(24, x0..x9), x10..x19), x20..x23)
1659 if (midLen == LEFT_ARGS)
1660 return rightFill;
1661 else
1662 return MethodHandles.collectArguments(rightFill, 0, midFill);
1663 }
1664
1665 static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM
1666
1667 /** Return a method handle that takes the indicated number of
1668 * typed arguments and returns an array of them.
1669 * The type argument is the array type.
1670 */
1671 static MethodHandle varargsArray(Class<?> arrayType, int nargs) {
1672 Class<?> elemType = arrayType.getComponentType();
1673 if (elemType == null) throw new IllegalArgumentException("not an array: "+arrayType);
1674 // FIXME: Need more special casing and caching here.
1675 if (nargs >= MAX_JVM_ARITY/2 - 1) {
1676 int slots = nargs;
1677 final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH
1678 if (slots <= MAX_ARRAY_SLOTS && elemType.isPrimitive())
1679 slots *= Wrapper.forPrimitiveType(elemType).stackSlots();
1680 if (slots > MAX_ARRAY_SLOTS)
1681 throw new IllegalArgumentException("too many arguments: "+arrayType.getSimpleName()+", length "+nargs);
1682 }
1683 if (elemType == Object.class)
1684 return varargsArray(nargs);
1685 // other cases: primitive arrays, subtypes of Object[]
1686 MethodHandle cache[] = Makers.TYPED_COLLECTORS.get(elemType);
1687 MethodHandle mh = nargs < cache.length ? cache[nargs] : null;
1688 if (mh != null) return mh;
1689 if (nargs == 0) {
1690 Object example = java.lang.reflect.Array.newInstance(arrayType.getComponentType(), 0);
1691 mh = MethodHandles.constant(arrayType, example);
1692 } else if (elemType.isPrimitive()) {
1693 MethodHandle builder = getConstantHandle(MH_fillNewArray);
1694 MethodHandle producer = buildArrayProducer(arrayType);
1695 mh = buildVarargsArray(builder, producer, nargs);
1696 } else {
1697 Class<? extends Object[]> objArrayType = arrayType.asSubclass(Object[].class);
1698 Object[] example = Arrays.copyOf(NO_ARGS_ARRAY, 0, objArrayType);
1699 MethodHandle builder = getConstantHandle(MH_fillNewTypedArray).bindTo(example);
1700 MethodHandle producer = getConstantHandle(MH_arrayIdentity); // must be weakly typed
1701 mh = buildVarargsArray(builder, producer, nargs);
1702 }
1703 mh = mh.asType(MethodType.methodType(arrayType, Collections.<Class<?>>nCopies(nargs, elemType)));
1704 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY);
1705 assert(assertCorrectArity(mh, nargs));
1706 if (nargs < cache.length)
1707 cache[nargs] = mh;
1708 return mh;
1709 }
1710
1711 private static MethodHandle buildArrayProducer(Class<?> arrayType) {
1712 Class<?> elemType = arrayType.getComponentType();
1713 assert(elemType.isPrimitive());
1714 return getConstantHandle(MH_copyAsPrimitiveArray).bindTo(Wrapper.forPrimitiveType(elemType));
1715 }
1716
1717 /*non-public*/ static void assertSame(Object mh1, Object mh2) {
1718 if (mh1 != mh2) {
1719 String msg = String.format("mh1 != mh2: mh1 = %s (form: %s); mh2 = %s (form: %s)",
1720 mh1, ((MethodHandle)mh1).form,
1721 mh2, ((MethodHandle)mh2).form);
1722 throw newInternalError(msg);
1723 }
1724 }
1725
1726 // Local constant functions:
1727
1728 /* non-public */
1729 static final byte NF_checkSpreadArgument = 0,
1730 NF_guardWithCatch = 1,
1731 NF_throwException = 2,
1732 NF_tryFinally = 3,
1733 NF_loop = 4,
1734 NF_profileBoolean = 5,
1735 NF_LIMIT = 6;
1736
1737 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
1738
1739 static NamedFunction getFunction(byte func) {
1740 NamedFunction nf = NFS[func];
1741 if (nf != null) {
1742 return nf;
1743 }
1744 return NFS[func] = createFunction(func);
1745 }
1746
1747 private static NamedFunction createFunction(byte func) {
1748 try {
1749 switch (func) {
1750 case NF_checkSpreadArgument:
1751 return new NamedFunction(MethodHandleImpl.class
1752 .getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
1753 case NF_guardWithCatch:
1754 return new NamedFunction(MethodHandleImpl.class
1755 .getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class,
1756 MethodHandle.class, Object[].class));
1757 case NF_tryFinally:
1758 return new NamedFunction(MethodHandleImpl.class
1759 .getDeclaredMethod("tryFinally", MethodHandle.class, MethodHandle.class, Object[].class));
1760 case NF_loop:
1761 return new NamedFunction(MethodHandleImpl.class
1762 .getDeclaredMethod("loop", BasicType[].class, LoopClauses.class, Object[].class));
1763 case NF_throwException:
1764 return new NamedFunction(MethodHandleImpl.class
1765 .getDeclaredMethod("throwException", Throwable.class));
1766 case NF_profileBoolean:
1767 return new NamedFunction(MethodHandleImpl.class
1768 .getDeclaredMethod("profileBoolean", boolean.class, int[].class));
1769 default:
1770 throw new InternalError("Undefined function: " + func);
1771 }
1772 } catch (ReflectiveOperationException ex) {
1773 throw newInternalError(ex);
1774 }
1775 }
1776
1777 static {
1778 SharedSecrets.setJavaLangInvokeAccess(new JavaLangInvokeAccess() {
1779 @Override
1780 public Object newMemberName() {
1781 return new MemberName();
1782 }
1783
1784 @Override
1785 public String getName(Object mname) {
1786 MemberName memberName = (MemberName)mname;
1787 return memberName.getName();
1788 }
1789 @Override
1790 public Class<?> getDeclaringClass(Object mname) {
1791 MemberName memberName = (MemberName)mname;
1792 return memberName.getDeclaringClass();
1793 }
1794
1795 @Override
1796 public MethodType getMethodType(Object mname) {
1797 MemberName memberName = (MemberName)mname;
1798 return memberName.getMethodType();
1799 }
1800
1801 @Override
1802 public String getMethodDescriptor(Object mname) {
1803 MemberName memberName = (MemberName)mname;
1804 return memberName.getMethodDescriptor();
1805 }
1806
1807 @Override
1808 public boolean isNative(Object mname) {
1809 MemberName memberName = (MemberName)mname;
1810 return memberName.isNative();
1811 }
1812
1813 @Override
1814 public byte[] generateDirectMethodHandleHolderClassBytes(
1815 String className, MethodType[] methodTypes, int[] types) {
1816 return GenerateJLIClassesHelper
1817 .generateDirectMethodHandleHolderClassBytes(
1818 className, methodTypes, types);
1819 }
1820
1821 @Override
1822 public byte[] generateDelegatingMethodHandleHolderClassBytes(
1823 String className, MethodType[] methodTypes) {
1824 return GenerateJLIClassesHelper
1825 .generateDelegatingMethodHandleHolderClassBytes(
1826 className, methodTypes);
1827 }
1828
1829 @Override
1830 public Map.Entry<String, byte[]> generateConcreteBMHClassBytes(
1831 final String types) {
1832 return GenerateJLIClassesHelper
1833 .generateConcreteBMHClassBytes(types);
1834 }
1835
1836 @Override
1837 public byte[] generateBasicFormsClassBytes(final String className) {
1838 return GenerateJLIClassesHelper
1839 .generateBasicFormsClassBytes(className);
1840 }
1841
1842 @Override
1843 public byte[] generateInvokersHolderClassBytes(final String className,
1844 MethodType[] invokerMethodTypes,
1845 MethodType[] callSiteMethodTypes) {
1846 return GenerateJLIClassesHelper
1847 .generateInvokersHolderClassBytes(className,
1848 invokerMethodTypes, callSiteMethodTypes);
1849 }
1850
1851 });
1852 }
1853
1854 /** Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore(). */
1855 private static MethodHandle unboxResultHandle(Class<?> returnType) {
1856 if (returnType.isPrimitive()) {
1857 if (returnType == void.class) {
1858 return ValueConversions.ignore();
1859 } else {
1860 Wrapper w = Wrapper.forPrimitiveType(returnType);
1861 return ValueConversions.unboxExact(w);
1862 }
1863 } else {
1864 return MethodHandles.identity(Object.class);
1865 }
1866 }
1867
1868 /**
1869 * Assembles a loop method handle from the given handles and type information.
1870 *
1871 * @param tloop the return type of the loop.
1872 * @param targs types of the arguments to be passed to the loop.
1873 * @param init sanitized array of initializers for loop-local variables.
1874 * @param step sanitited array of loop bodies.
1875 * @param pred sanitized array of predicates.
1876 * @param fini sanitized array of loop finalizers.
1877 *
1878 * @return a handle that, when invoked, will execute the loop.
1879 */
1880 static MethodHandle makeLoop(Class<?> tloop, List<Class<?>> targs, List<MethodHandle> init, List<MethodHandle> step,
1881 List<MethodHandle> pred, List<MethodHandle> fini) {
1882 MethodType type = MethodType.methodType(tloop, targs);
1883 BasicType[] initClauseTypes =
1884 init.stream().map(h -> h.type().returnType()).map(BasicType::basicType).toArray(BasicType[]::new);
1885 LambdaForm form = makeLoopForm(type.basicType(), initClauseTypes);
1886
1887 // Prepare auxiliary method handles used during LambdaForm interpretation.
1888 // Box arguments and wrap them into Object[]: ValueConversions.array().
1889 MethodType varargsType = type.changeReturnType(Object[].class);
1890 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
1891 MethodHandle unboxResult = unboxResultHandle(tloop);
1892
1893 LoopClauses clauseData =
1894 new LoopClauses(new MethodHandle[][]{toArray(init), toArray(step), toArray(pred), toArray(fini)});
1895 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLL();
1896 BoundMethodHandle mh;
1897 try {
1898 mh = (BoundMethodHandle) data.factory().invokeBasic(type, form, (Object) clauseData,
1899 (Object) collectArgs, (Object) unboxResult);
1900 } catch (Throwable ex) {
1901 throw uncaughtException(ex);
1902 }
1903 assert(mh.type() == type);
1904 return mh;
1905 }
1906
1907 private static MethodHandle[] toArray(List<MethodHandle> l) {
1908 return l.toArray(new MethodHandle[0]);
1909 }
1910
1911 /**
1912 * Loops introduce some complexity as they can have additional local state. Hence, LambdaForms for loops are
1913 * generated from a template. The LambdaForm template shape for the loop combinator is as follows (assuming one
1914 * reference parameter passed in {@code a1}, and a reference return type, with the return value represented by
1915 * {@code t12}):
1916 * <blockquote><pre>{@code
1917 * loop=Lambda(a0:L,a1:L)=>{
1918 * t2:L=BoundMethodHandle$Species_L3.argL0(a0:L); // LoopClauses holding init, step, pred, fini handles
1919 * t3:L=BoundMethodHandle$Species_L3.argL1(a0:L); // helper handle to box the arguments into an Object[]
1920 * t4:L=BoundMethodHandle$Species_L3.argL2(a0:L); // helper handle to unbox the result
1921 * t5:L=MethodHandle.invokeBasic(t3:L,a1:L); // box the arguments into an Object[]
1922 * t6:L=MethodHandleImpl.loop(null,t2:L,t3:L); // call the loop executor
1923 * t7:L=MethodHandle.invokeBasic(t4:L,t6:L);t7:L} // unbox the result; return the result
1924 * }</pre></blockquote>
1925 * <p>
1926 * {@code argL0} is a LoopClauses instance holding, in a 2-dimensional array, the init, step, pred, and fini method
1927 * handles. {@code argL1} and {@code argL2} are auxiliary method handles: {@code argL1} boxes arguments and wraps
1928 * them into {@code Object[]} ({@code ValueConversions.array()}), and {@code argL2} unboxes the result if necessary
1929 * ({@code ValueConversions.unbox()}).
1930 * <p>
1931 * Having {@code t3} and {@code t4} passed in via a BMH and not hardcoded in the lambda form allows to share lambda
1932 * forms among loop combinators with the same basic type.
1933 * <p>
1934 * The above template is instantiated by using the {@link LambdaFormEditor} to replace the {@code null} argument to
1935 * the {@code loop} invocation with the {@code BasicType} array describing the loop clause types. This argument is
1936 * ignored in the loop invoker, but will be extracted and used in {@linkplain InvokerBytecodeGenerator#emitLoop(int)
1937 * bytecode generation}.
1938 */
1939 private static LambdaForm makeLoopForm(MethodType basicType, BasicType[] localVarTypes) {
1940 MethodType lambdaType = basicType.invokerType();
1941
1942 final int THIS_MH = 0; // the BMH_LLL
1943 final int ARG_BASE = 1; // start of incoming arguments
1944 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
1945
1946 int nameCursor = ARG_LIMIT;
1947 final int GET_CLAUSE_DATA = nameCursor++;
1948 final int GET_COLLECT_ARGS = nameCursor++;
1949 final int GET_UNBOX_RESULT = nameCursor++;
1950 final int BOXED_ARGS = nameCursor++;
1951 final int LOOP = nameCursor++;
1952 final int UNBOX_RESULT = nameCursor++;
1953
1954 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_LOOP);
1955 if (lform == null) {
1956 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
1957
1958 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLL();
1959 names[THIS_MH] = names[THIS_MH].withConstraint(data);
1960 names[GET_CLAUSE_DATA] = new Name(data.getterFunction(0), names[THIS_MH]);
1961 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(1), names[THIS_MH]);
1962 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(2), names[THIS_MH]);
1963
1964 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
1965 MethodType collectArgsType = basicType.changeReturnType(Object.class);
1966 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
1967 Object[] args = new Object[invokeBasic.type().parameterCount()];
1968 args[0] = names[GET_COLLECT_ARGS];
1969 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT - ARG_BASE);
1970 names[BOXED_ARGS] = new Name(new NamedFunction(invokeBasic, Intrinsic.LOOP), args);
1971
1972 // t_{i+1}:L=MethodHandleImpl.loop(localTypes:L,clauses:L,t_{i}:L);
1973 Object[] lArgs =
1974 new Object[]{null, // placeholder for BasicType[] localTypes - will be added by LambdaFormEditor
1975 names[GET_CLAUSE_DATA], names[BOXED_ARGS]};
1976 names[LOOP] = new Name(getFunction(NF_loop), lArgs);
1977
1978 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
1979 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
1980 Object[] unboxArgs = new Object[]{names[GET_UNBOX_RESULT], names[LOOP]};
1981 names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
1982
1983 lform = basicType.form().setCachedLambdaForm(MethodTypeForm.LF_LOOP,
1984 new LambdaForm(lambdaType.parameterCount(), names, Kind.LOOP));
1985 }
1986
1987 // BOXED_ARGS is the index into the names array where the loop idiom starts
1988 return lform.editor().noteLoopLocalTypesForm(BOXED_ARGS, localVarTypes);
1989 }
1990
1991 static class LoopClauses {
1992 @Stable final MethodHandle[][] clauses;
1993 LoopClauses(MethodHandle[][] clauses) {
1994 assert clauses.length == 4;
1995 this.clauses = clauses;
1996 }
1997 @Override
1998 public String toString() {
1999 StringBuffer sb = new StringBuffer("LoopClauses -- ");
2000 for (int i = 0; i < 4; ++i) {
2001 if (i > 0) {
2002 sb.append(" ");
2003 }
2004 sb.append('<').append(i).append(">: ");
2005 MethodHandle[] hs = clauses[i];
2006 for (int j = 0; j < hs.length; ++j) {
2007 if (j > 0) {
2008 sb.append(" ");
2009 }
2010 sb.append('*').append(j).append(": ").append(hs[j]).append('\n');
2011 }
2012 }
2013 sb.append(" --\n");
2014 return sb.toString();
2015 }
2016 }
2017
2018 /**
2019 * Intrinsified during LambdaForm compilation
2020 * (see {@link InvokerBytecodeGenerator#emitLoop(int)}).
2021 */
2022 @LambdaForm.Hidden
2023 static Object loop(BasicType[] localTypes, LoopClauses clauseData, Object... av) throws Throwable {
2024 final MethodHandle[] init = clauseData.clauses[0];
2025 final MethodHandle[] step = clauseData.clauses[1];
2026 final MethodHandle[] pred = clauseData.clauses[2];
2027 final MethodHandle[] fini = clauseData.clauses[3];
2028 int varSize = (int) Stream.of(init).filter(h -> h.type().returnType() != void.class).count();
2029 int nArgs = init[0].type().parameterCount();
2030 Object[] varsAndArgs = new Object[varSize + nArgs];
2031 for (int i = 0, v = 0; i < init.length; ++i) {
2032 MethodHandle ih = init[i];
2033 if (ih.type().returnType() == void.class) {
2034 ih.invokeWithArguments(av);
2035 } else {
2036 varsAndArgs[v++] = ih.invokeWithArguments(av);
2037 }
2038 }
2039 System.arraycopy(av, 0, varsAndArgs, varSize, nArgs);
2040 final int nSteps = step.length;
2041 for (; ; ) {
2042 for (int i = 0, v = 0; i < nSteps; ++i) {
2043 MethodHandle p = pred[i];
2044 MethodHandle s = step[i];
2045 MethodHandle f = fini[i];
2046 if (s.type().returnType() == void.class) {
2047 s.invokeWithArguments(varsAndArgs);
2048 } else {
2049 varsAndArgs[v++] = s.invokeWithArguments(varsAndArgs);
2050 }
2051 if (!(boolean) p.invokeWithArguments(varsAndArgs)) {
2052 return f.invokeWithArguments(varsAndArgs);
2053 }
2054 }
2055 }
2056 }
2057
2058 /**
2059 * This method is bound as the predicate in {@linkplain MethodHandles#countedLoop(MethodHandle, MethodHandle,
2060 * MethodHandle) counting loops}.
2061 *
2062 * @param limit the upper bound of the parameter, statically bound at loop creation time.
2063 * @param counter the counter parameter, passed in during loop execution.
2064 *
2065 * @return whether the counter has reached the limit.
2066 */
2067 static boolean countedLoopPredicate(int limit, int counter) {
2068 return counter < limit;
2069 }
2070
2071 /**
2072 * This method is bound as the step function in {@linkplain MethodHandles#countedLoop(MethodHandle, MethodHandle,
2073 * MethodHandle) counting loops} to increment the counter.
2074 *
2075 * @param limit the upper bound of the loop counter (ignored).
2076 * @param counter the loop counter.
2077 *
2078 * @return the loop counter incremented by 1.
2079 */
2080 static int countedLoopStep(int limit, int counter) {
2081 return counter + 1;
2082 }
2083
2084 /**
2085 * This is bound to initialize the loop-local iterator in {@linkplain MethodHandles#iteratedLoop iterating loops}.
2086 *
2087 * @param it the {@link Iterable} over which the loop iterates.
2088 *
2089 * @return an {@link Iterator} over the argument's elements.
2090 */
2091 static Iterator<?> initIterator(Iterable<?> it) {
2092 return it.iterator();
2093 }
2094
2095 /**
2096 * This method is bound as the predicate in {@linkplain MethodHandles#iteratedLoop iterating loops}.
2097 *
2098 * @param it the iterator to be checked.
2099 *
2100 * @return {@code true} iff there are more elements to iterate over.
2101 */
2102 static boolean iteratePredicate(Iterator<?> it) {
2103 return it.hasNext();
2104 }
2105
2106 /**
2107 * This method is bound as the step for retrieving the current value from the iterator in {@linkplain
2108 * MethodHandles#iteratedLoop iterating loops}.
2109 *
2110 * @param it the iterator.
2111 *
2112 * @return the next element from the iterator.
2113 */
2114 static Object iterateNext(Iterator<?> it) {
2115 return it.next();
2116 }
2117
2118 /**
2119 * Makes a {@code try-finally} handle that conforms to the type constraints.
2120 *
2121 * @param target the target to execute in a {@code try-finally} block.
2122 * @param cleanup the cleanup to execute in the {@code finally} block.
2123 * @param rtype the result type of the entire construct.
2124 * @param argTypes the types of the arguments.
2125 *
2126 * @return a handle on the constructed {@code try-finally} block.
2127 */
2128 static MethodHandle makeTryFinally(MethodHandle target, MethodHandle cleanup, Class<?> rtype, List<Class<?>> argTypes) {
2129 MethodType type = MethodType.methodType(rtype, argTypes);
2130 LambdaForm form = makeTryFinallyForm(type.basicType());
2131
2132 // Prepare auxiliary method handles used during LambdaForm interpretation.
2133 // Box arguments and wrap them into Object[]: ValueConversions.array().
2134 MethodType varargsType = type.changeReturnType(Object[].class);
2135 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType);
2136 MethodHandle unboxResult = unboxResultHandle(rtype);
2137
2138 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLL();
2139 BoundMethodHandle mh;
2140 try {
2141 mh = (BoundMethodHandle) data.factory().invokeBasic(type, form, (Object) target, (Object) cleanup,
2142 (Object) collectArgs, (Object) unboxResult);
2143 } catch (Throwable ex) {
2144 throw uncaughtException(ex);
2145 }
2146 assert(mh.type() == type);
2147 return mh;
2148 }
2149
2150 /**
2151 * The LambdaForm shape for the tryFinally combinator is as follows (assuming one reference parameter passed in
2152 * {@code a1}, and a reference return type, with the return value represented by {@code t8}):
2153 * <blockquote><pre>{@code
2154 * tryFinally=Lambda(a0:L,a1:L)=>{
2155 * t2:L=BoundMethodHandle$Species_LLLL.argL0(a0:L); // target method handle
2156 * t3:L=BoundMethodHandle$Species_LLLL.argL1(a0:L); // cleanup method handle
2157 * t4:L=BoundMethodHandle$Species_LLLL.argL2(a0:L); // helper handle to box the arguments into an Object[]
2158 * t5:L=BoundMethodHandle$Species_LLLL.argL3(a0:L); // helper handle to unbox the result
2159 * t6:L=MethodHandle.invokeBasic(t4:L,a1:L); // box the arguments into an Object[]
2160 * t7:L=MethodHandleImpl.tryFinally(t2:L,t3:L,t6:L); // call the tryFinally executor
2161 * t8:L=MethodHandle.invokeBasic(t5:L,t7:L);t8:L} // unbox the result; return the result
2162 * }</pre></blockquote>
2163 * <p>
2164 * {@code argL0} and {@code argL1} are the target and cleanup method handles.
2165 * {@code argL2} and {@code argL3} are auxiliary method handles: {@code argL2} boxes arguments and wraps them into
2166 * {@code Object[]} ({@code ValueConversions.array()}), and {@code argL3} unboxes the result if necessary
2167 * ({@code ValueConversions.unbox()}).
2168 * <p>
2169 * Having {@code t4} and {@code t5} passed in via a BMH and not hardcoded in the lambda form allows to share lambda
2170 * forms among tryFinally combinators with the same basic type.
2171 */
2172 private static LambdaForm makeTryFinallyForm(MethodType basicType) {
2173 MethodType lambdaType = basicType.invokerType();
2174
2175 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_TF);
2176 if (lform != null) {
2177 return lform;
2178 }
2179 final int THIS_MH = 0; // the BMH_LLLL
2180 final int ARG_BASE = 1; // start of incoming arguments
2181 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
2182
2183 int nameCursor = ARG_LIMIT;
2184 final int GET_TARGET = nameCursor++;
2185 final int GET_CLEANUP = nameCursor++;
2186 final int GET_COLLECT_ARGS = nameCursor++;
2187 final int GET_UNBOX_RESULT = nameCursor++;
2188 final int BOXED_ARGS = nameCursor++;
2189 final int TRY_FINALLY = nameCursor++;
2190 final int UNBOX_RESULT = nameCursor++;
2191
2192 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
2193
2194 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLL();
2195 names[THIS_MH] = names[THIS_MH].withConstraint(data);
2196 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
2197 names[GET_CLEANUP] = new Name(data.getterFunction(1), names[THIS_MH]);
2198 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(2), names[THIS_MH]);
2199 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(3), names[THIS_MH]);
2200
2201 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
2202 MethodType collectArgsType = basicType.changeReturnType(Object.class);
2203 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
2204 Object[] args = new Object[invokeBasic.type().parameterCount()];
2205 args[0] = names[GET_COLLECT_ARGS];
2206 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
2207 names[BOXED_ARGS] = new Name(new NamedFunction(invokeBasic, Intrinsic.TRY_FINALLY), args);
2208
2209 // t_{i+1}:L=MethodHandleImpl.tryFinally(target:L,exType:L,catcher:L,t_{i}:L);
2210 Object[] tfArgs = new Object[] {names[GET_TARGET], names[GET_CLEANUP], names[BOXED_ARGS]};
2211 names[TRY_FINALLY] = new Name(getFunction(NF_tryFinally), tfArgs);
2212
2213 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
2214 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
2215 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_FINALLY]};
2216 names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs);
2217
2218 lform = new LambdaForm(lambdaType.parameterCount(), names, Kind.TRY_FINALLY);
2219
2220 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_TF, lform);
2221 }
2222
2223 /**
2224 * Intrinsified during LambdaForm compilation
2225 * (see {@link InvokerBytecodeGenerator#emitTryFinally emitTryFinally}).
2226 */
2227 @LambdaForm.Hidden
2228 static Object tryFinally(MethodHandle target, MethodHandle cleanup, Object... av) throws Throwable {
2229 Throwable t = null;
2230 Object r = null;
2231 try {
2232 r = target.invokeWithArguments(av);
2233 } catch (Throwable thrown) {
2234 t = thrown;
2235 throw t;
2236 } finally {
2237 Object[] args = target.type().returnType() == void.class ? prepend(av, t) : prepend(av, t, r);
2238 r = cleanup.invokeWithArguments(args);
2239 }
2240 return r;
2241 }
2242
2243 // Indexes into constant method handles:
2244 static final int
2245 MH_cast = 0,
2246 MH_selectAlternative = 1,
2247 MH_copyAsPrimitiveArray = 2,
2248 MH_fillNewTypedArray = 3,
2249 MH_fillNewArray = 4,
2250 MH_arrayIdentity = 5,
2251 MH_countedLoopPred = 6,
2252 MH_countedLoopStep = 7,
2253 MH_initIterator = 8,
2254 MH_iteratePred = 9,
2255 MH_iterateNext = 10,
2256 MH_Array_newInstance = 11,
2257 MH_LIMIT = 12;
2258
2259 static MethodHandle getConstantHandle(int idx) {
2260 MethodHandle handle = HANDLES[idx];
2261 if (handle != null) {
2262 return handle;
2263 }
2264 return setCachedHandle(idx, makeConstantHandle(idx));
2265 }
2266
2267 private static synchronized MethodHandle setCachedHandle(int idx, final MethodHandle method) {
2268 // Simulate a CAS, to avoid racy duplication of results.
2269 MethodHandle prev = HANDLES[idx];
2270 if (prev != null) {
2271 return prev;
2272 }
2273 HANDLES[idx] = method;
2274 return method;
2275 }
2276
2277 // Local constant method handles:
2278 private static final @Stable MethodHandle[] HANDLES = new MethodHandle[MH_LIMIT];
2279
2280 private static MethodHandle makeConstantHandle(int idx) {
2281 try {
2282 switch (idx) {
2283 case MH_cast:
2284 return IMPL_LOOKUP.findVirtual(Class.class, "cast",
2285 MethodType.methodType(Object.class, Object.class));
2286 case MH_copyAsPrimitiveArray:
2287 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "copyAsPrimitiveArray",
2288 MethodType.methodType(Object.class, Wrapper.class, Object[].class));
2289 case MH_arrayIdentity:
2290 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "identity",
2291 MethodType.methodType(Object[].class, Object[].class));
2292 case MH_fillNewArray:
2293 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "fillNewArray",
2294 MethodType.methodType(Object[].class, Integer.class, Object[].class));
2295 case MH_fillNewTypedArray:
2296 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "fillNewTypedArray",
2297 MethodType.methodType(Object[].class, Object[].class, Integer.class, Object[].class));
2298 case MH_selectAlternative:
2299 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "selectAlternative",
2300 MethodType.methodType(MethodHandle.class, boolean.class, MethodHandle.class, MethodHandle.class));
2301 case MH_countedLoopPred:
2302 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "countedLoopPredicate",
2303 MethodType.methodType(boolean.class, int.class, int.class));
2304 case MH_countedLoopStep:
2305 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "countedLoopStep",
2306 MethodType.methodType(int.class, int.class, int.class));
2307 case MH_initIterator:
2308 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "initIterator",
2309 MethodType.methodType(Iterator.class, Iterable.class));
2310 case MH_iteratePred:
2311 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "iteratePredicate",
2312 MethodType.methodType(boolean.class, Iterator.class));
2313 case MH_iterateNext:
2314 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "iterateNext",
2315 MethodType.methodType(Object.class, Iterator.class));
2316 case MH_Array_newInstance:
2317 return IMPL_LOOKUP.findStatic(Array.class, "newInstance",
2318 MethodType.methodType(Object.class, Class.class, int.class));
2319 }
2320 } catch (ReflectiveOperationException ex) {
2321 throw newInternalError(ex);
2322 }
2323 throw newInternalError("Unknown function index: " + idx);
2324 }
2325 }