1 /*
2 * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.invoke;
27
28 import java.security.AccessController;
29 import java.security.PrivilegedAction;
30 import java.util.Arrays;
31 import java.util.HashMap;
32 import sun.invoke.empty.Empty;
33 import sun.invoke.util.ValueConversions;
34 import sun.invoke.util.VerifyType;
35 import sun.invoke.util.Wrapper;
36 import sun.reflect.CallerSensitive;
37 import sun.reflect.Reflection;
38 import static java.lang.invoke.LambdaForm.*;
39 import static java.lang.invoke.MethodHandleStatics.*;
40 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
41
42 /**
43 * Trusted implementation code for MethodHandle.
44 * @author jrose
45 */
46 /*non-public*/ abstract class MethodHandleImpl {
47 /// Factory methods to create method handles:
48
49 static void initStatics() {
50 // Trigger selected static initializations.
51 MemberName.Factory.INSTANCE.getClass();
52 }
53
54 static MethodHandle makeArrayElementAccessor(Class<?> arrayClass, boolean isSetter) {
55 if (!arrayClass.isArray())
56 throw newIllegalArgumentException("not an array: "+arrayClass);
57 MethodHandle accessor = ArrayAccessor.getAccessor(arrayClass, isSetter);
58 MethodType srcType = accessor.type().erase();
59 MethodType lambdaType = srcType.invokerType();
60 Name[] names = arguments(1, lambdaType);
61 Name[] args = Arrays.copyOfRange(names, 1, 1 + srcType.parameterCount());
62 names[names.length - 1] = new Name(accessor.asType(srcType), (Object[]) args);
63 LambdaForm form = new LambdaForm("getElement", lambdaType.parameterCount(), names);
64 MethodHandle mh = SimpleMethodHandle.make(srcType, form);
65 if (ArrayAccessor.needCast(arrayClass)) {
66 mh = mh.bindTo(arrayClass);
67 }
68 mh = mh.asType(ArrayAccessor.correctType(arrayClass, isSetter));
69 return mh;
70 }
71
72 static final class ArrayAccessor {
73 /// Support for array element access
74 static final HashMap<Class<?>, MethodHandle> GETTER_CACHE = new HashMap<>(); // TODO use it
75 static final HashMap<Class<?>, MethodHandle> SETTER_CACHE = new HashMap<>(); // TODO use it
76
77 static int getElementI(int[] a, int i) { return a[i]; }
78 static long getElementJ(long[] a, int i) { return a[i]; }
79 static float getElementF(float[] a, int i) { return a[i]; }
80 static double getElementD(double[] a, int i) { return a[i]; }
81 static boolean getElementZ(boolean[] a, int i) { return a[i]; }
82 static byte getElementB(byte[] a, int i) { return a[i]; }
83 static short getElementS(short[] a, int i) { return a[i]; }
84 static char getElementC(char[] a, int i) { return a[i]; }
85 static Object getElementL(Object[] a, int i) { return a[i]; }
86
87 static void setElementI(int[] a, int i, int x) { a[i] = x; }
88 static void setElementJ(long[] a, int i, long x) { a[i] = x; }
89 static void setElementF(float[] a, int i, float x) { a[i] = x; }
90 static void setElementD(double[] a, int i, double x) { a[i] = x; }
91 static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; }
92 static void setElementB(byte[] a, int i, byte x) { a[i] = x; }
93 static void setElementS(short[] a, int i, short x) { a[i] = x; }
94 static void setElementC(char[] a, int i, char x) { a[i] = x; }
95 static void setElementL(Object[] a, int i, Object x) { a[i] = x; }
96
97 static Object getElementL(Class<?> arrayClass, Object[] a, int i) { arrayClass.cast(a); return a[i]; }
98 static void setElementL(Class<?> arrayClass, Object[] a, int i, Object x) { arrayClass.cast(a); a[i] = x; }
99
100 static boolean needCast(Class<?> arrayClass) {
101 Class<?> elemClass = arrayClass.getComponentType();
102 return !elemClass.isPrimitive() && elemClass != Object.class;
103 }
104 static String name(Class<?> arrayClass, boolean isSetter) {
105 Class<?> elemClass = arrayClass.getComponentType();
106 if (elemClass == null) throw newIllegalArgumentException("not an array", arrayClass);
107 return (!isSetter ? "getElement" : "setElement") + Wrapper.basicTypeChar(elemClass);
108 }
109 static final boolean USE_WEAKLY_TYPED_ARRAY_ACCESSORS = false; // FIXME: decide
110 static MethodType type(Class<?> arrayClass, boolean isSetter) {
111 Class<?> elemClass = arrayClass.getComponentType();
112 Class<?> arrayArgClass = arrayClass;
113 if (!elemClass.isPrimitive()) {
114 arrayArgClass = Object[].class;
115 if (USE_WEAKLY_TYPED_ARRAY_ACCESSORS)
116 arrayArgClass = Object.class;
117 }
118 if (!needCast(arrayClass)) {
119 return !isSetter ?
120 MethodType.methodType(elemClass, arrayArgClass, int.class) :
121 MethodType.methodType(void.class, arrayArgClass, int.class, elemClass);
122 } else {
123 Class<?> classArgClass = Class.class;
124 if (USE_WEAKLY_TYPED_ARRAY_ACCESSORS)
125 classArgClass = Object.class;
126 return !isSetter ?
127 MethodType.methodType(Object.class, classArgClass, arrayArgClass, int.class) :
128 MethodType.methodType(void.class, classArgClass, arrayArgClass, int.class, Object.class);
129 }
130 }
131 static MethodType correctType(Class<?> arrayClass, boolean isSetter) {
132 Class<?> elemClass = arrayClass.getComponentType();
133 return !isSetter ?
134 MethodType.methodType(elemClass, arrayClass, int.class) :
135 MethodType.methodType(void.class, arrayClass, int.class, elemClass);
136 }
137 static MethodHandle getAccessor(Class<?> arrayClass, boolean isSetter) {
138 String name = name(arrayClass, isSetter);
139 MethodType type = type(arrayClass, isSetter);
140 try {
141 return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type);
142 } catch (ReflectiveOperationException ex) {
143 throw uncaughtException(ex);
144 }
145 }
146 }
147
148 /**
149 * Create a JVM-level adapter method handle to conform the given method
150 * handle to the similar newType, using only pairwise argument conversions.
151 * For each argument, convert incoming argument to the exact type needed.
152 * The argument conversions allowed are casting, boxing and unboxing,
153 * integral widening or narrowing, and floating point widening or narrowing.
154 * @param srcType required call type
155 * @param target original method handle
156 * @param level which strength of conversion is allowed
157 * @return an adapter to the original handle with the desired new type,
158 * or the original target if the types are already identical
159 * or null if the adaptation cannot be made
160 */
161 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType, int level) {
162 assert(level >= 0 && level <= 2);
163 MethodType dstType = target.type();
164 assert(dstType.parameterCount() == target.type().parameterCount());
165 if (srcType == dstType)
166 return target;
167
168 // Calculate extra arguments (temporaries) required in the names array.
169 // FIXME: Use an ArrayList<Name>. Some arguments require more than one conversion step.
170 final int INARG_COUNT = srcType.parameterCount();
171 int conversions = 0;
172 boolean[] needConv = new boolean[1+INARG_COUNT];
173 for (int i = 0; i <= INARG_COUNT; i++) {
174 Class<?> src = (i == INARG_COUNT) ? dstType.returnType() : srcType.parameterType(i);
175 Class<?> dst = (i == INARG_COUNT) ? srcType.returnType() : dstType.parameterType(i);
176 if (!VerifyType.isNullConversion(src, dst, false) ||
177 level <= 1 && dst.isInterface() && !dst.isAssignableFrom(src)) {
178 needConv[i] = true;
179 conversions++;
180 }
181 }
182 boolean retConv = needConv[INARG_COUNT];
183 if (retConv && srcType.returnType() == void.class) {
184 retConv = false;
185 conversions--;
186 }
187
188 final int IN_MH = 0;
189 final int INARG_BASE = 1;
190 final int INARG_LIMIT = INARG_BASE + INARG_COUNT;
191 final int NAME_LIMIT = INARG_LIMIT + conversions + 1;
192 final int RETURN_CONV = (!retConv ? -1 : NAME_LIMIT - 1);
193 final int OUT_CALL = (!retConv ? NAME_LIMIT : RETURN_CONV) - 1;
194 final int RESULT = (srcType.returnType() == void.class ? -1 : NAME_LIMIT - 1);
195
196 // Now build a LambdaForm.
197 MethodType lambdaType = srcType.basicType().invokerType();
198 Name[] names = arguments(NAME_LIMIT - INARG_LIMIT, lambdaType);
199
200 // Collect the arguments to the outgoing call, maybe with conversions:
201 final int OUTARG_BASE = 0; // target MH is Name.function, name Name.arguments[0]
202 Object[] outArgs = new Object[OUTARG_BASE + INARG_COUNT];
203
204 int nameCursor = INARG_LIMIT;
205 for (int i = 0; i < INARG_COUNT; i++) {
206 Class<?> src = srcType.parameterType(i);
207 Class<?> dst = dstType.parameterType(i);
208
209 if (!needConv[i]) {
210 // do nothing: difference is trivial
211 outArgs[OUTARG_BASE + i] = names[INARG_BASE + i];
212 continue;
213 }
214
215 // Tricky case analysis follows.
216 MethodHandle fn = null;
217 if (src.isPrimitive()) {
218 if (dst.isPrimitive()) {
219 fn = ValueConversions.convertPrimitive(src, dst);
220 } else {
221 Wrapper w = Wrapper.forPrimitiveType(src);
222 MethodHandle boxMethod = ValueConversions.box(w);
223 if (dst == w.wrapperType())
224 fn = boxMethod;
225 else
226 fn = boxMethod.asType(MethodType.methodType(dst, src));
227 }
228 } else {
229 if (dst.isPrimitive()) {
230 // Caller has boxed a primitive. Unbox it for the target.
231 Wrapper w = Wrapper.forPrimitiveType(dst);
232 if (level == 0 || VerifyType.isNullConversion(src, w.wrapperType(), false)) {
233 fn = ValueConversions.unbox(dst);
234 } else if (src == Object.class || !Wrapper.isWrapperType(src)) {
235 // Examples: Object->int, Number->int, Comparable->int; Byte->int, Character->int
236 // must include additional conversions
237 // src must be examined at runtime, to detect Byte, Character, etc.
238 MethodHandle unboxMethod = (level == 1
239 ? ValueConversions.unbox(dst)
240 : ValueConversions.unboxCast(dst));
241 fn = unboxMethod;
242 } else {
243 // Example: Byte->int
244 // Do this by reformulating the problem to Byte->byte.
245 Class<?> srcPrim = Wrapper.forWrapperType(src).primitiveType();
246 MethodHandle unbox = ValueConversions.unbox(srcPrim);
247 // Compose the two conversions. FIXME: should make two Names for this job
248 fn = unbox.asType(MethodType.methodType(dst, src));
249 }
250 } else {
251 // Simple reference conversion.
252 // Note: Do not check for a class hierarchy relation
253 // between src and dst. In all cases a 'null' argument
254 // will pass the cast conversion.
255 fn = ValueConversions.cast(dst, Lazy.MH_castReference);
256 }
257 }
258 Name conv = new Name(fn, names[INARG_BASE + i]);
259 assert(names[nameCursor] == null);
260 names[nameCursor++] = conv;
261 assert(outArgs[OUTARG_BASE + i] == null);
262 outArgs[OUTARG_BASE + i] = conv;
263 }
264
265 // Build argument array for the call.
266 assert(nameCursor == OUT_CALL);
267 names[OUT_CALL] = new Name(target, outArgs);
268
269 if (RETURN_CONV < 0) {
270 assert(OUT_CALL == names.length-1);
271 } else {
272 Class<?> needReturn = srcType.returnType();
273 Class<?> haveReturn = dstType.returnType();
274 MethodHandle fn;
275 Object[] arg = { names[OUT_CALL] };
276 if (haveReturn == void.class) {
277 // synthesize a zero value for the given void
278 Object zero = Wrapper.forBasicType(needReturn).zero();
279 fn = MethodHandles.constant(needReturn, zero);
280 arg = new Object[0]; // don't pass names[OUT_CALL] to conversion
281 } else {
282 MethodHandle identity = MethodHandles.identity(needReturn);
283 MethodType needConversion = identity.type().changeParameterType(0, haveReturn);
284 fn = makePairwiseConvert(identity, needConversion, level);
285 }
286 assert(names[RETURN_CONV] == null);
287 names[RETURN_CONV] = new Name(fn, arg);
288 assert(RETURN_CONV == names.length-1);
289 }
290
291 LambdaForm form = new LambdaForm("convert", lambdaType.parameterCount(), names, RESULT);
292 return SimpleMethodHandle.make(srcType, form);
293 }
294
295 /**
296 * Identity function, with reference cast.
297 * @param t an arbitrary reference type
298 * @param x an arbitrary reference value
299 * @return the same value x
300 */
301 @ForceInline
302 @SuppressWarnings("unchecked")
303 static <T,U> T castReference(Class<? extends T> t, U x) {
304 // inlined Class.cast because we can't ForceInline it
305 if (x != null && !t.isInstance(x))
306 throw newClassCastException(t, x);
307 return (T) x;
308 }
309
310 private static ClassCastException newClassCastException(Class<?> t, Object obj) {
311 return new ClassCastException("Cannot cast " + obj.getClass().getName() + " to " + t.getName());
312 }
313
314 static MethodHandle makeReferenceIdentity(Class<?> refType) {
315 MethodType lambdaType = MethodType.genericMethodType(1).invokerType();
316 Name[] names = arguments(1, lambdaType);
317 names[names.length - 1] = new Name(ValueConversions.identity(), names[1]);
318 LambdaForm form = new LambdaForm("identity", lambdaType.parameterCount(), names);
319 return SimpleMethodHandle.make(MethodType.methodType(refType, refType), form);
320 }
321
322 static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
323 MethodType type = target.type();
324 int last = type.parameterCount() - 1;
325 if (type.parameterType(last) != arrayType)
326 target = target.asType(type.changeParameterType(last, arrayType));
327 target = target.asFixedArity(); // make sure this attribute is turned off
328 return new AsVarargsCollector(target, target.type(), arrayType);
329 }
330
331 static class AsVarargsCollector extends MethodHandle {
332 private final MethodHandle target;
333 private final Class<?> arrayType;
334 private /*@Stable*/ MethodHandle asCollectorCache;
335
336 AsVarargsCollector(MethodHandle target, MethodType type, Class<?> arrayType) {
337 super(type, reinvokerForm(target));
338 this.target = target;
339 this.arrayType = arrayType;
340 this.asCollectorCache = target.asCollector(arrayType, 0);
341 }
342
343 @Override MethodHandle reinvokerTarget() { return target; }
344
345 @Override
346 public boolean isVarargsCollector() {
347 return true;
348 }
349
350 @Override
351 public MethodHandle asFixedArity() {
352 return target;
353 }
354
355 @Override
356 public MethodHandle asTypeUncached(MethodType newType) {
357 MethodType type = this.type();
358 int collectArg = type.parameterCount() - 1;
359 int newArity = newType.parameterCount();
360 if (newArity == collectArg+1 &&
361 type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
362 // if arity and trailing parameter are compatible, do normal thing
363 return asTypeCache = asFixedArity().asType(newType);
364 }
365 // check cache
366 MethodHandle acc = asCollectorCache;
367 if (acc != null && acc.type().parameterCount() == newArity)
368 return asTypeCache = acc.asType(newType);
369 // build and cache a collector
370 int arrayLength = newArity - collectArg;
371 MethodHandle collector;
372 try {
373 collector = asFixedArity().asCollector(arrayType, arrayLength);
374 assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
375 } catch (IllegalArgumentException ex) {
376 throw new WrongMethodTypeException("cannot build collector", ex);
377 }
378 asCollectorCache = collector;
379 return asTypeCache = collector.asType(newType);
380 }
381
382 @Override
383 MethodHandle setVarargs(MemberName member) {
384 if (member.isVarargs()) return this;
385 return asFixedArity();
386 }
387
388 @Override
389 MethodHandle viewAsType(MethodType newType) {
390 if (newType.lastParameterType() != type().lastParameterType())
391 throw new InternalError();
392 MethodHandle newTarget = asFixedArity().viewAsType(newType);
393 // put back the varargs bit:
394 return new AsVarargsCollector(newTarget, newType, arrayType);
395 }
396
397 @Override
398 MemberName internalMemberName() {
399 return asFixedArity().internalMemberName();
400 }
401 @Override
402 Class<?> internalCallerClass() {
403 return asFixedArity().internalCallerClass();
404 }
405
406 /*non-public*/
407 @Override
408 boolean isInvokeSpecial() {
409 return asFixedArity().isInvokeSpecial();
410 }
411
412
413 @Override
414 MethodHandle bindArgument(int pos, BasicType basicType, Object value) {
415 return asFixedArity().bindArgument(pos, basicType, value);
416 }
417
418 @Override
419 MethodHandle bindReceiver(Object receiver) {
420 return asFixedArity().bindReceiver(receiver);
421 }
422
423 @Override
424 MethodHandle dropArguments(MethodType srcType, int pos, int drops) {
425 return asFixedArity().dropArguments(srcType, pos, drops);
426 }
427
428 @Override
429 MethodHandle permuteArguments(MethodType newType, int[] reorder) {
430 return asFixedArity().permuteArguments(newType, reorder);
431 }
432 }
433
434 /** Factory method: Spread selected argument. */
435 static MethodHandle makeSpreadArguments(MethodHandle target,
436 Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
437 MethodType targetType = target.type();
438
439 for (int i = 0; i < spreadArgCount; i++) {
440 Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i);
441 if (arg == null) arg = Object.class;
442 targetType = targetType.changeParameterType(spreadArgPos + i, arg);
443 }
444 target = target.asType(targetType);
445
446 MethodType srcType = targetType
447 .replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType);
448 // Now build a LambdaForm.
449 MethodType lambdaType = srcType.invokerType();
450 Name[] names = arguments(spreadArgCount + 2, lambdaType);
451 int nameCursor = lambdaType.parameterCount();
452 int[] indexes = new int[targetType.parameterCount()];
453
454 for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) {
455 Class<?> src = lambdaType.parameterType(i);
456 if (i == spreadArgPos) {
457 // Spread the array.
458 MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType);
459 Name array = names[argIndex];
460 names[nameCursor++] = new Name(Lazy.NF_checkSpreadArgument, array, spreadArgCount);
461 for (int j = 0; j < spreadArgCount; i++, j++) {
462 indexes[i] = nameCursor;
463 names[nameCursor++] = new Name(aload, array, j);
464 }
465 } else if (i < indexes.length) {
466 indexes[i] = argIndex;
467 }
468 }
469 assert(nameCursor == names.length-1); // leave room for the final call
470
471 // Build argument array for the call.
472 Name[] targetArgs = new Name[targetType.parameterCount()];
473 for (int i = 0; i < targetType.parameterCount(); i++) {
474 int idx = indexes[i];
475 targetArgs[i] = names[idx];
476 }
477 names[names.length - 1] = new Name(target, (Object[]) targetArgs);
478
479 LambdaForm form = new LambdaForm("spread", lambdaType.parameterCount(), names);
480 return SimpleMethodHandle.make(srcType, form);
481 }
482
483 static void checkSpreadArgument(Object av, int n) {
484 if (av == null) {
485 if (n == 0) return;
486 } else if (av instanceof Object[]) {
487 int len = ((Object[])av).length;
488 if (len == n) return;
489 } else {
490 int len = java.lang.reflect.Array.getLength(av);
491 if (len == n) return;
492 }
493 // fall through to error:
494 throw newIllegalArgumentException("array is not of length "+n);
495 }
496
497 /**
498 * Pre-initialized NamedFunctions for bootstrapping purposes.
499 * Factored in an inner class to delay initialization until first usage.
500 */
501 private static class Lazy {
502 private static final Class<?> MHI = MethodHandleImpl.class;
503
504 static final NamedFunction NF_checkSpreadArgument;
505 static final NamedFunction NF_guardWithCatch;
506 static final NamedFunction NF_selectAlternative;
507 static final NamedFunction NF_throwException;
508
509 static final MethodHandle MH_castReference;
510
511 static {
512 try {
513 NF_checkSpreadArgument = new NamedFunction(MHI.getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
514 NF_guardWithCatch = new NamedFunction(MHI.getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class,
515 MethodHandle.class, Object[].class));
516 NF_selectAlternative = new NamedFunction(MHI.getDeclaredMethod("selectAlternative", boolean.class, MethodHandle.class,
517 MethodHandle.class));
518 NF_throwException = new NamedFunction(MHI.getDeclaredMethod("throwException", Throwable.class));
519
520 NF_checkSpreadArgument.resolve();
521 NF_guardWithCatch.resolve();
522 NF_selectAlternative.resolve();
523 NF_throwException.resolve();
524
525 MethodType mt = MethodType.methodType(Object.class, Class.class, Object.class);
526 MH_castReference = IMPL_LOOKUP.findStatic(MHI, "castReference", mt);
527 } catch (ReflectiveOperationException ex) {
528 throw newInternalError(ex);
529 }
530 }
531 }
532
533 /** Factory method: Collect or filter selected argument(s). */
534 static MethodHandle makeCollectArguments(MethodHandle target,
535 MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) {
536 MethodType targetType = target.type(); // (a..., c, [b...])=>r
537 MethodType collectorType = collector.type(); // (b...)=>c
538 int collectArgCount = collectorType.parameterCount();
539 Class<?> collectValType = collectorType.returnType();
540 int collectValCount = (collectValType == void.class ? 0 : 1);
541 MethodType srcType = targetType // (a..., [b...])=>r
542 .dropParameterTypes(collectArgPos, collectArgPos+collectValCount);
543 if (!retainOriginalArgs) { // (a..., b...)=>r
544 srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterList());
545 }
546 // in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ]
547 // out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ]
548 // out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ]
549
550 // Now build a LambdaForm.
551 MethodType lambdaType = srcType.invokerType();
552 Name[] names = arguments(2, lambdaType);
553 final int collectNamePos = names.length - 2;
554 final int targetNamePos = names.length - 1;
555
556 Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount);
557 names[collectNamePos] = new Name(collector, (Object[]) collectorArgs);
558
559 // Build argument array for the target.
560 // Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ].
561 // Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ].
562 Name[] targetArgs = new Name[targetType.parameterCount()];
563 int inputArgPos = 1; // incoming LF args to copy to target
564 int targetArgPos = 0; // fill pointer for targetArgs
565 int chunk = collectArgPos; // |headArgs|
566 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
567 inputArgPos += chunk;
568 targetArgPos += chunk;
569 if (collectValType != void.class) {
570 targetArgs[targetArgPos++] = names[collectNamePos];
571 }
572 chunk = collectArgCount;
573 if (retainOriginalArgs) {
574 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
575 targetArgPos += chunk; // optionally pass on the collected chunk
576 }
577 inputArgPos += chunk;
578 chunk = targetArgs.length - targetArgPos; // all the rest
579 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
580 assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also
581 names[targetNamePos] = new Name(target, (Object[]) targetArgs);
582
583 LambdaForm form = new LambdaForm("collect", lambdaType.parameterCount(), names);
584 return SimpleMethodHandle.make(srcType, form);
585 }
586
587 @LambdaForm.Hidden
588 static
589 MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
590 return testResult ? target : fallback;
591 }
592
593 static
594 MethodHandle makeGuardWithTest(MethodHandle test,
595 MethodHandle target,
596 MethodHandle fallback) {
597 MethodType basicType = target.type().basicType();
598 MethodHandle invokeBasic = MethodHandles.basicInvoker(basicType);
599 int arity = basicType.parameterCount();
600 int extraNames = 3;
601 MethodType lambdaType = basicType.invokerType();
602 Name[] names = arguments(extraNames, lambdaType);
603
604 Object[] testArgs = Arrays.copyOfRange(names, 1, 1 + arity, Object[].class);
605 Object[] targetArgs = Arrays.copyOfRange(names, 0, 1 + arity, Object[].class);
606
607 // call test
608 names[arity + 1] = new Name(test, testArgs);
609
610 // call selectAlternative
611 Object[] selectArgs = { names[arity + 1], target, fallback };
612 names[arity + 2] = new Name(Lazy.NF_selectAlternative, selectArgs);
613 targetArgs[0] = names[arity + 2];
614
615 // call target or fallback
616 names[arity + 3] = new Name(new NamedFunction(invokeBasic), targetArgs);
617
618 LambdaForm form = new LambdaForm("guard", lambdaType.parameterCount(), names);
619 return SimpleMethodHandle.make(target.type(), form);
620 }
621
622 /**
623 * The LambaForm shape for catchException combinator is the following:
624 * <blockquote><pre>{@code
625 * guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{
626 * t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L);
627 * t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L);
628 * t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L);
629 * t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L);
630 * t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L);
631 * t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L);
632 * t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L);
633 * t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I}
634 * }</pre></blockquote>
635 *
636 * argL0 and argL2 are target and catcher method handles. argL1 is exception class.
637 * argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[]
638 * (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()).
639 *
640 * Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms
641 * among catchException combinators with the same basic type.
642 */
643 private static LambdaForm makeGuardWithCatchForm(MethodType basicType) {
644 MethodType lambdaType = basicType.invokerType();
645
646 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC);
647 if (lform != null) {
648 return lform;
649 }
650 final int THIS_MH = 0; // the BMH_LLLLL
651 final int ARG_BASE = 1; // start of incoming arguments
652 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount();
653
654 int nameCursor = ARG_LIMIT;
655 final int GET_TARGET = nameCursor++;
656 final int GET_CLASS = nameCursor++;
657 final int GET_CATCHER = nameCursor++;
658 final int GET_COLLECT_ARGS = nameCursor++;
659 final int GET_UNBOX_RESULT = nameCursor++;
660 final int BOXED_ARGS = nameCursor++;
661 final int TRY_CATCH = nameCursor++;
662 final int UNBOX_RESULT = nameCursor++;
663
664 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType);
665
666 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
667 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]);
668 names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]);
669 names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]);
670 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]);
671 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]);
672
673 // FIXME: rework argument boxing/result unboxing logic for LF interpretation
674
675 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...);
676 MethodType collectArgsType = basicType.changeReturnType(Object.class);
677 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType);
678 Object[] args = new Object[invokeBasic.type().parameterCount()];
679 args[0] = names[GET_COLLECT_ARGS];
680 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE);
681 names[BOXED_ARGS] = new Name(new NamedFunction(invokeBasic), args);
682
683 // t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L);
684 Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]};
685 names[TRY_CATCH] = new Name(Lazy.NF_guardWithCatch, gwcArgs);
686
687 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L);
688 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class));
689 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]};
690 names[UNBOX_RESULT] = new Name(new NamedFunction(invokeBasicUnbox), unboxArgs);
691
692 lform = new LambdaForm("guardWithCatch", lambdaType.parameterCount(), names);
693
694 basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform);
695 return lform;
696 }
697
698 static
699 MethodHandle makeGuardWithCatch(MethodHandle target,
700 Class<? extends Throwable> exType,
701 MethodHandle catcher) {
702 MethodType type = target.type();
703 LambdaForm form = makeGuardWithCatchForm(type.basicType());
704
705 // Prepare auxiliary method handles used during LambdaForm interpreation.
706 // Box arguments and wrap them into Object[]: ValueConversions.array().
707 MethodType varargsType = type.changeReturnType(Object[].class);
708 MethodHandle collectArgs = ValueConversions.varargsArray(type.parameterCount())
709 .asType(varargsType);
710 // Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore().
711 MethodHandle unboxResult;
712 if (type.returnType().isPrimitive()) {
713 unboxResult = ValueConversions.unbox(type.returnType());
714 } else {
715 unboxResult = ValueConversions.identity();
716 }
717
718 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL();
719 BoundMethodHandle mh;
720 try {
721 mh = (BoundMethodHandle)
722 data.constructor[0].invokeBasic(type, form, (Object) target, (Object) exType, (Object) catcher,
723 (Object) collectArgs, (Object) unboxResult);
724 } catch (Throwable ex) {
725 throw uncaughtException(ex);
726 }
727 assert(mh.type() == type);
728 return mh;
729 }
730
731 /**
732 * Intrinsified during LambdaForm compilation
733 * (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}).
734 */
735 @LambdaForm.Hidden
736 static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher,
737 Object... av) throws Throwable {
738 // Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case.
739 try {
740 return target.asFixedArity().invokeWithArguments(av);
741 } catch (Throwable t) {
742 if (!exType.isInstance(t)) throw t;
743 return catcher.asFixedArity().invokeWithArguments(prepend(t, av));
744 }
745 }
746
747 /** Prepend an element {@code elem} to an {@code array}. */
748 @LambdaForm.Hidden
749 private static Object[] prepend(Object elem, Object[] array) {
750 Object[] newArray = new Object[array.length+1];
751 newArray[0] = elem;
752 System.arraycopy(array, 0, newArray, 1, array.length);
753 return newArray;
754 }
755
756 static
757 MethodHandle throwException(MethodType type) {
758 assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
759 int arity = type.parameterCount();
760 if (arity > 1) {
761 return throwException(type.dropParameterTypes(1, arity)).dropArguments(type, 1, arity-1);
762 }
763 return makePairwiseConvert(Lazy.NF_throwException.resolvedHandle(), type, 2);
764 }
765
766 static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
767
768 static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
769 static MethodHandle fakeMethodHandleInvoke(MemberName method) {
770 int idx;
771 assert(method.isMethodHandleInvoke());
772 switch (method.getName()) {
773 case "invoke": idx = 0; break;
774 case "invokeExact": idx = 1; break;
775 default: throw new InternalError(method.getName());
776 }
777 MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
778 if (mh != null) return mh;
779 MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
780 MethodHandle.class, Object[].class);
781 mh = throwException(type);
782 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
783 if (!method.getInvocationType().equals(mh.type()))
784 throw new InternalError(method.toString());
785 mh = mh.withInternalMemberName(method);
786 mh = mh.asVarargsCollector(Object[].class);
787 assert(method.isVarargs());
788 FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
789 return mh;
790 }
791
792 /**
793 * Create an alias for the method handle which, when called,
794 * appears to be called from the same class loader and protection domain
795 * as hostClass.
796 * This is an expensive no-op unless the method which is called
797 * is sensitive to its caller. A small number of system methods
798 * are in this category, including Class.forName and Method.invoke.
799 */
800 static
801 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
802 return BindCaller.bindCaller(mh, hostClass);
803 }
804
805 // Put the whole mess into its own nested class.
806 // That way we can lazily load the code and set up the constants.
807 private static class BindCaller {
808 static
809 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
810 // Do not use this function to inject calls into system classes.
811 if (hostClass == null
812 || (hostClass.isArray() ||
813 hostClass.isPrimitive() ||
814 hostClass.getName().startsWith("java.") ||
815 hostClass.getName().startsWith("sun."))) {
816 throw new InternalError(); // does not happen, and should not anyway
817 }
818 // For simplicity, convert mh to a varargs-like method.
819 MethodHandle vamh = prepareForInvoker(mh);
820 // Cache the result of makeInjectedInvoker once per argument class.
821 MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
822 return restoreToType(bccInvoker.bindTo(vamh), mh.type(), mh.internalMemberName(), hostClass);
823 }
824
825 private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
826 Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null);
827 if (hostClass.getClassLoader() != bcc.getClassLoader())
828 throw new InternalError(hostClass.getName()+" (CL)");
829 try {
830 if (hostClass.getProtectionDomain() != bcc.getProtectionDomain())
831 throw new InternalError(hostClass.getName()+" (PD)");
832 } catch (SecurityException ex) {
833 // Self-check was blocked by security manager. This is OK.
834 // In fact the whole try body could be turned into an assertion.
835 }
836 try {
837 MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class));
838 init.invokeExact(); // force initialization of the class
839 } catch (Throwable ex) {
840 throw uncaughtException(ex);
841 }
842 MethodHandle bccInvoker;
843 try {
844 MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
845 bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT);
846 } catch (ReflectiveOperationException ex) {
847 throw uncaughtException(ex);
848 }
849 // Test the invoker, to ensure that it really injects into the right place.
850 try {
851 MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
852 Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc});
853 } catch (Throwable ex) {
854 throw new InternalError(ex);
855 }
856 return bccInvoker;
857 }
858 private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() {
859 @Override protected MethodHandle computeValue(Class<?> hostClass) {
860 return makeInjectedInvoker(hostClass);
861 }
862 };
863
864 // Adapt mh so that it can be called directly from an injected invoker:
865 private static MethodHandle prepareForInvoker(MethodHandle mh) {
866 mh = mh.asFixedArity();
867 MethodType mt = mh.type();
868 int arity = mt.parameterCount();
869 MethodHandle vamh = mh.asType(mt.generic());
870 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
871 vamh = vamh.asSpreader(Object[].class, arity);
872 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames
873 return vamh;
874 }
875
876 // Undo the adapter effect of prepareForInvoker:
877 private static MethodHandle restoreToType(MethodHandle vamh, MethodType type,
878 MemberName member,
879 Class<?> hostClass) {
880 MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount());
881 mh = mh.asType(type);
882 mh = new WrappedMember(mh, type, member, hostClass);
883 return mh;
884 }
885
886 private static final MethodHandle MH_checkCallerClass;
887 static {
888 final Class<?> THIS_CLASS = BindCaller.class;
889 assert(checkCallerClass(THIS_CLASS, THIS_CLASS));
890 try {
891 MH_checkCallerClass = IMPL_LOOKUP
892 .findStatic(THIS_CLASS, "checkCallerClass",
893 MethodType.methodType(boolean.class, Class.class, Class.class));
894 assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS, THIS_CLASS));
895 } catch (Throwable ex) {
896 throw new InternalError(ex);
897 }
898 }
899
900 @CallerSensitive
901 private static boolean checkCallerClass(Class<?> expected, Class<?> expected2) {
902 // This method is called via MH_checkCallerClass and so it's
903 // correct to ask for the immediate caller here.
904 Class<?> actual = Reflection.getCallerClass();
905 if (actual != expected && actual != expected2)
906 throw new InternalError("found "+actual.getName()+", expected "+expected.getName()
907 +(expected == expected2 ? "" : ", or else "+expected2.getName()));
908 return true;
909 }
910
911 private static final byte[] T_BYTES;
912 static {
913 final Object[] values = {null};
914 AccessController.doPrivileged(new PrivilegedAction<Void>() {
915 public Void run() {
916 try {
917 Class<T> tClass = T.class;
918 String tName = tClass.getName();
919 String tResource = tName.substring(tName.lastIndexOf('.')+1)+".class";
920 java.net.URLConnection uconn = tClass.getResource(tResource).openConnection();
921 int len = uconn.getContentLength();
922 byte[] bytes = new byte[len];
923 try (java.io.InputStream str = uconn.getInputStream()) {
924 int nr = str.read(bytes);
925 if (nr != len) throw new java.io.IOException(tResource);
926 }
927 values[0] = bytes;
928 } catch (java.io.IOException ex) {
929 throw new InternalError(ex);
930 }
931 return null;
932 }
933 });
934 T_BYTES = (byte[]) values[0];
935 }
936
937 // The following class is used as a template for Unsafe.defineAnonymousClass:
938 private static class T {
939 static void init() { } // side effect: initializes this class
940 static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable {
941 return vamh.invokeExact(args);
942 }
943 }
944 }
945
946
947 /** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */
948 static class WrappedMember extends MethodHandle {
949 private final MethodHandle target;
950 private final MemberName member;
951 private final Class<?> callerClass;
952
953 private WrappedMember(MethodHandle target, MethodType type, MemberName member, Class<?> callerClass) {
954 super(type, reinvokerForm(target));
955 this.target = target;
956 this.member = member;
957 this.callerClass = callerClass;
958 }
959
960 @Override
961 MethodHandle reinvokerTarget() {
962 return target;
963 }
964 @Override
965 public MethodHandle asTypeUncached(MethodType newType) {
966 // This MH is an alias for target, except for the MemberName
967 // Drop the MemberName if there is any conversion.
968 return asTypeCache = target.asType(newType);
969 }
970 @Override
971 MemberName internalMemberName() {
972 return member;
973 }
974 @Override
975 Class<?> internalCallerClass() {
976 return callerClass;
977 }
978 @Override
979 boolean isInvokeSpecial() {
980 return target.isInvokeSpecial();
981 }
982 @Override
983 MethodHandle viewAsType(MethodType newType) {
984 return new WrappedMember(target, newType, member, callerClass);
985 }
986 }
987
988 static MethodHandle makeWrappedMember(MethodHandle target, MemberName member) {
989 if (member.equals(target.internalMemberName()))
990 return target;
991 return new WrappedMember(target, target.type(), member, null);
992 }
993
994 }