1 /* 2 * Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang.invoke; 27 28 import java.security.AccessController; 29 import java.security.PrivilegedAction; 30 import java.util.ArrayList; 31 import java.util.Arrays; 32 import java.util.Collections; 33 import java.util.function.Function; 34 35 import sun.invoke.empty.Empty; 36 import sun.invoke.util.ValueConversions; 37 import sun.invoke.util.VerifyType; 38 import sun.invoke.util.Wrapper; 39 import jdk.internal.HotSpotIntrinsicCandidate; 40 import sun.reflect.CallerSensitive; 41 import sun.reflect.Reflection; 42 import static java.lang.invoke.LambdaForm.*; 43 import static java.lang.invoke.MethodHandleStatics.*; 44 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP; 45 46 /** 47 * Trusted implementation code for MethodHandle. 48 * @author jrose 49 */ 50 /*non-public*/ abstract class MethodHandleImpl { 51 // Do not adjust this except for special platforms: 52 private static final int MAX_ARITY; 53 static { 54 final Object[] values = { 255 }; 55 AccessController.doPrivileged(new PrivilegedAction<>() { 56 @Override 57 public Void run() { 58 values[0] = Integer.getInteger(MethodHandleImpl.class.getName()+".MAX_ARITY", 255); 59 return null; 60 } 61 }); 62 MAX_ARITY = (Integer) values[0]; 63 } 64 65 /// Factory methods to create method handles: 66 67 static void initStatics() { 68 // Trigger selected static initializations. 69 MemberName.Factory.INSTANCE.getClass(); 70 } 71 72 static MethodHandle makeArrayElementAccessor(Class<?> arrayClass, boolean isSetter) { 73 if (arrayClass == Object[].class) 74 return (isSetter ? ArrayAccessor.OBJECT_ARRAY_SETTER : ArrayAccessor.OBJECT_ARRAY_GETTER); 75 if (!arrayClass.isArray()) 76 throw newIllegalArgumentException("not an array: "+arrayClass); 77 MethodHandle[] cache = ArrayAccessor.TYPED_ACCESSORS.get(arrayClass); 78 int cacheIndex = (isSetter ? ArrayAccessor.SETTER_INDEX : ArrayAccessor.GETTER_INDEX); 79 MethodHandle mh = cache[cacheIndex]; 80 if (mh != null) return mh; 81 mh = ArrayAccessor.getAccessor(arrayClass, isSetter); 82 MethodType correctType = ArrayAccessor.correctType(arrayClass, isSetter); 83 if (mh.type() != correctType) { 84 assert(mh.type().parameterType(0) == Object[].class); 85 assert((isSetter ? mh.type().parameterType(2) : mh.type().returnType()) == Object.class); 86 assert(isSetter || correctType.parameterType(0).getComponentType() == correctType.returnType()); 87 // safe to view non-strictly, because element type follows from array type 88 mh = mh.viewAsType(correctType, false); 89 } 90 mh = makeIntrinsic(mh, (isSetter ? Intrinsic.ARRAY_STORE : Intrinsic.ARRAY_LOAD)); 91 // Atomically update accessor cache. 92 synchronized(cache) { 93 if (cache[cacheIndex] == null) { 94 cache[cacheIndex] = mh; 95 } else { 96 // Throw away newly constructed accessor and use cached version. 97 mh = cache[cacheIndex]; 98 } 99 } 100 return mh; 101 } 102 103 static final class ArrayAccessor { 104 /// Support for array element access 105 static final int GETTER_INDEX = 0, SETTER_INDEX = 1, INDEX_LIMIT = 2; 106 static final ClassValue<MethodHandle[]> TYPED_ACCESSORS 107 = new ClassValue<MethodHandle[]>() { 108 @Override 109 protected MethodHandle[] computeValue(Class<?> type) { 110 return new MethodHandle[INDEX_LIMIT]; 111 } 112 }; 113 static final MethodHandle OBJECT_ARRAY_GETTER, OBJECT_ARRAY_SETTER; 114 static { 115 MethodHandle[] cache = TYPED_ACCESSORS.get(Object[].class); 116 cache[GETTER_INDEX] = OBJECT_ARRAY_GETTER = makeIntrinsic(getAccessor(Object[].class, false), Intrinsic.ARRAY_LOAD); 117 cache[SETTER_INDEX] = OBJECT_ARRAY_SETTER = makeIntrinsic(getAccessor(Object[].class, true), Intrinsic.ARRAY_STORE); 118 119 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_GETTER.internalMemberName())); 120 assert(InvokerBytecodeGenerator.isStaticallyInvocable(ArrayAccessor.OBJECT_ARRAY_SETTER.internalMemberName())); 121 } 122 123 static int getElementI(int[] a, int i) { return a[i]; } 124 static long getElementJ(long[] a, int i) { return a[i]; } 125 static float getElementF(float[] a, int i) { return a[i]; } 126 static double getElementD(double[] a, int i) { return a[i]; } 127 static boolean getElementZ(boolean[] a, int i) { return a[i]; } 128 static byte getElementB(byte[] a, int i) { return a[i]; } 129 static short getElementS(short[] a, int i) { return a[i]; } 130 static char getElementC(char[] a, int i) { return a[i]; } 131 static Object getElementL(Object[] a, int i) { return a[i]; } 132 133 static void setElementI(int[] a, int i, int x) { a[i] = x; } 134 static void setElementJ(long[] a, int i, long x) { a[i] = x; } 135 static void setElementF(float[] a, int i, float x) { a[i] = x; } 136 static void setElementD(double[] a, int i, double x) { a[i] = x; } 137 static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; } 138 static void setElementB(byte[] a, int i, byte x) { a[i] = x; } 139 static void setElementS(short[] a, int i, short x) { a[i] = x; } 140 static void setElementC(char[] a, int i, char x) { a[i] = x; } 141 static void setElementL(Object[] a, int i, Object x) { a[i] = x; } 142 143 static String name(Class<?> arrayClass, boolean isSetter) { 144 Class<?> elemClass = arrayClass.getComponentType(); 145 if (elemClass == null) throw newIllegalArgumentException("not an array", arrayClass); 146 return (!isSetter ? "getElement" : "setElement") + Wrapper.basicTypeChar(elemClass); 147 } 148 static MethodType type(Class<?> arrayClass, boolean isSetter) { 149 Class<?> elemClass = arrayClass.getComponentType(); 150 Class<?> arrayArgClass = arrayClass; 151 if (!elemClass.isPrimitive()) { 152 arrayArgClass = Object[].class; 153 elemClass = Object.class; 154 } 155 return !isSetter ? 156 MethodType.methodType(elemClass, arrayArgClass, int.class) : 157 MethodType.methodType(void.class, arrayArgClass, int.class, elemClass); 158 } 159 static MethodType correctType(Class<?> arrayClass, boolean isSetter) { 160 Class<?> elemClass = arrayClass.getComponentType(); 161 return !isSetter ? 162 MethodType.methodType(elemClass, arrayClass, int.class) : 163 MethodType.methodType(void.class, arrayClass, int.class, elemClass); 164 } 165 static MethodHandle getAccessor(Class<?> arrayClass, boolean isSetter) { 166 String name = name(arrayClass, isSetter); 167 MethodType type = type(arrayClass, isSetter); 168 try { 169 return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type); 170 } catch (ReflectiveOperationException ex) { 171 throw uncaughtException(ex); 172 } 173 } 174 } 175 176 /** 177 * Create a JVM-level adapter method handle to conform the given method 178 * handle to the similar newType, using only pairwise argument conversions. 179 * For each argument, convert incoming argument to the exact type needed. 180 * The argument conversions allowed are casting, boxing and unboxing, 181 * integral widening or narrowing, and floating point widening or narrowing. 182 * @param srcType required call type 183 * @param target original method handle 184 * @param strict if true, only asType conversions are allowed; if false, explicitCastArguments conversions allowed 185 * @param monobox if true, unboxing conversions are assumed to be exactly typed (Integer to int only, not long or double) 186 * @return an adapter to the original handle with the desired new type, 187 * or the original target if the types are already identical 188 * or null if the adaptation cannot be made 189 */ 190 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType, 191 boolean strict, boolean monobox) { 192 MethodType dstType = target.type(); 193 if (srcType == dstType) 194 return target; 195 return makePairwiseConvertByEditor(target, srcType, strict, monobox); 196 } 197 198 private static int countNonNull(Object[] array) { 199 int count = 0; 200 for (Object x : array) { 201 if (x != null) ++count; 202 } 203 return count; 204 } 205 206 static MethodHandle makePairwiseConvertByEditor(MethodHandle target, MethodType srcType, 207 boolean strict, boolean monobox) { 208 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox); 209 int convCount = countNonNull(convSpecs); 210 if (convCount == 0) 211 return target.viewAsType(srcType, strict); 212 MethodType basicSrcType = srcType.basicType(); 213 MethodType midType = target.type().basicType(); 214 BoundMethodHandle mh = target.rebind(); 215 // FIXME: Reduce number of bindings when there is more than one Class conversion. 216 // FIXME: Reduce number of bindings when there are repeated conversions. 217 for (int i = 0; i < convSpecs.length-1; i++) { 218 Object convSpec = convSpecs[i]; 219 if (convSpec == null) continue; 220 MethodHandle fn; 221 if (convSpec instanceof Class) { 222 fn = Lazy.MH_cast.bindTo(convSpec); 223 } else { 224 fn = (MethodHandle) convSpec; 225 } 226 Class<?> newType = basicSrcType.parameterType(i); 227 if (--convCount == 0) 228 midType = srcType; 229 else 230 midType = midType.changeParameterType(i, newType); 231 LambdaForm form2 = mh.editor().filterArgumentForm(1+i, BasicType.basicType(newType)); 232 mh = mh.copyWithExtendL(midType, form2, fn); 233 mh = mh.rebind(); 234 } 235 Object convSpec = convSpecs[convSpecs.length-1]; 236 if (convSpec != null) { 237 MethodHandle fn; 238 if (convSpec instanceof Class) { 239 if (convSpec == void.class) 240 fn = null; 241 else 242 fn = Lazy.MH_cast.bindTo(convSpec); 243 } else { 244 fn = (MethodHandle) convSpec; 245 } 246 Class<?> newType = basicSrcType.returnType(); 247 assert(--convCount == 0); 248 midType = srcType; 249 if (fn != null) { 250 mh = mh.rebind(); // rebind if too complex 251 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), false); 252 mh = mh.copyWithExtendL(midType, form2, fn); 253 } else { 254 LambdaForm form2 = mh.editor().filterReturnForm(BasicType.basicType(newType), true); 255 mh = mh.copyWith(midType, form2); 256 } 257 } 258 assert(convCount == 0); 259 assert(mh.type().equals(srcType)); 260 return mh; 261 } 262 263 static MethodHandle makePairwiseConvertIndirect(MethodHandle target, MethodType srcType, 264 boolean strict, boolean monobox) { 265 assert(target.type().parameterCount() == srcType.parameterCount()); 266 // Calculate extra arguments (temporaries) required in the names array. 267 Object[] convSpecs = computeValueConversions(srcType, target.type(), strict, monobox); 268 final int INARG_COUNT = srcType.parameterCount(); 269 int convCount = countNonNull(convSpecs); 270 boolean retConv = (convSpecs[INARG_COUNT] != null); 271 boolean retVoid = srcType.returnType() == void.class; 272 if (retConv && retVoid) { 273 convCount -= 1; 274 retConv = false; 275 } 276 277 final int IN_MH = 0; 278 final int INARG_BASE = 1; 279 final int INARG_LIMIT = INARG_BASE + INARG_COUNT; 280 final int NAME_LIMIT = INARG_LIMIT + convCount + 1; 281 final int RETURN_CONV = (!retConv ? -1 : NAME_LIMIT - 1); 282 final int OUT_CALL = (!retConv ? NAME_LIMIT : RETURN_CONV) - 1; 283 final int RESULT = (retVoid ? -1 : NAME_LIMIT - 1); 284 285 // Now build a LambdaForm. 286 MethodType lambdaType = srcType.basicType().invokerType(); 287 Name[] names = arguments(NAME_LIMIT - INARG_LIMIT, lambdaType); 288 289 // Collect the arguments to the outgoing call, maybe with conversions: 290 final int OUTARG_BASE = 0; // target MH is Name.function, name Name.arguments[0] 291 Object[] outArgs = new Object[OUTARG_BASE + INARG_COUNT]; 292 293 int nameCursor = INARG_LIMIT; 294 for (int i = 0; i < INARG_COUNT; i++) { 295 Object convSpec = convSpecs[i]; 296 if (convSpec == null) { 297 // do nothing: difference is trivial 298 outArgs[OUTARG_BASE + i] = names[INARG_BASE + i]; 299 continue; 300 } 301 302 Name conv; 303 if (convSpec instanceof Class) { 304 Class<?> convClass = (Class<?>) convSpec; 305 conv = new Name(Lazy.MH_cast, convClass, names[INARG_BASE + i]); 306 } else { 307 MethodHandle fn = (MethodHandle) convSpec; 308 conv = new Name(fn, names[INARG_BASE + i]); 309 } 310 assert(names[nameCursor] == null); 311 names[nameCursor++] = conv; 312 assert(outArgs[OUTARG_BASE + i] == null); 313 outArgs[OUTARG_BASE + i] = conv; 314 } 315 316 // Build argument array for the call. 317 assert(nameCursor == OUT_CALL); 318 names[OUT_CALL] = new Name(target, outArgs); 319 320 Object convSpec = convSpecs[INARG_COUNT]; 321 if (!retConv) { 322 assert(OUT_CALL == names.length-1); 323 } else { 324 Name conv; 325 if (convSpec == void.class) { 326 conv = new Name(LambdaForm.constantZero(BasicType.basicType(srcType.returnType()))); 327 } else if (convSpec instanceof Class) { 328 Class<?> convClass = (Class<?>) convSpec; 329 conv = new Name(Lazy.MH_cast, convClass, names[OUT_CALL]); 330 } else { 331 MethodHandle fn = (MethodHandle) convSpec; 332 if (fn.type().parameterCount() == 0) 333 conv = new Name(fn); // don't pass retval to void conversion 334 else 335 conv = new Name(fn, names[OUT_CALL]); 336 } 337 assert(names[RETURN_CONV] == null); 338 names[RETURN_CONV] = conv; 339 assert(RETURN_CONV == names.length-1); 340 } 341 342 LambdaForm form = new LambdaForm("convert", lambdaType.parameterCount(), names, RESULT); 343 return SimpleMethodHandle.make(srcType, form); 344 } 345 346 static Object[] computeValueConversions(MethodType srcType, MethodType dstType, 347 boolean strict, boolean monobox) { 348 final int INARG_COUNT = srcType.parameterCount(); 349 Object[] convSpecs = new Object[INARG_COUNT+1]; 350 for (int i = 0; i <= INARG_COUNT; i++) { 351 boolean isRet = (i == INARG_COUNT); 352 Class<?> src = isRet ? dstType.returnType() : srcType.parameterType(i); 353 Class<?> dst = isRet ? srcType.returnType() : dstType.parameterType(i); 354 if (!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)) { 355 convSpecs[i] = valueConversion(src, dst, strict, monobox); 356 } 357 } 358 return convSpecs; 359 } 360 static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType, 361 boolean strict) { 362 return makePairwiseConvert(target, srcType, strict, /*monobox=*/ false); 363 } 364 365 /** 366 * Find a conversion function from the given source to the given destination. 367 * This conversion function will be used as a LF NamedFunction. 368 * Return a Class object if a simple cast is needed. 369 * Return void.class if void is involved. 370 */ 371 static Object valueConversion(Class<?> src, Class<?> dst, boolean strict, boolean monobox) { 372 assert(!VerifyType.isNullConversion(src, dst, /*keepInterfaces=*/ strict)); // caller responsibility 373 if (dst == void.class) 374 return dst; 375 MethodHandle fn; 376 if (src.isPrimitive()) { 377 if (src == void.class) { 378 return void.class; // caller must recognize this specially 379 } else if (dst.isPrimitive()) { 380 // Examples: int->byte, byte->int, boolean->int (!strict) 381 fn = ValueConversions.convertPrimitive(src, dst); 382 } else { 383 // Examples: int->Integer, boolean->Object, float->Number 384 Wrapper wsrc = Wrapper.forPrimitiveType(src); 385 fn = ValueConversions.boxExact(wsrc); 386 assert(fn.type().parameterType(0) == wsrc.primitiveType()); 387 assert(fn.type().returnType() == wsrc.wrapperType()); 388 if (!VerifyType.isNullConversion(wsrc.wrapperType(), dst, strict)) { 389 // Corner case, such as int->Long, which will probably fail. 390 MethodType mt = MethodType.methodType(dst, src); 391 if (strict) 392 fn = fn.asType(mt); 393 else 394 fn = MethodHandleImpl.makePairwiseConvert(fn, mt, /*strict=*/ false); 395 } 396 } 397 } else if (dst.isPrimitive()) { 398 Wrapper wdst = Wrapper.forPrimitiveType(dst); 399 if (monobox || src == wdst.wrapperType()) { 400 // Use a strongly-typed unboxer, if possible. 401 fn = ValueConversions.unboxExact(wdst, strict); 402 } else { 403 // Examples: Object->int, Number->int, Comparable->int, Byte->int 404 // must include additional conversions 405 // src must be examined at runtime, to detect Byte, Character, etc. 406 fn = (strict 407 ? ValueConversions.unboxWiden(wdst) 408 : ValueConversions.unboxCast(wdst)); 409 } 410 } else { 411 // Simple reference conversion. 412 // Note: Do not check for a class hierarchy relation 413 // between src and dst. In all cases a 'null' argument 414 // will pass the cast conversion. 415 return dst; 416 } 417 assert(fn.type().parameterCount() <= 1) : "pc"+Arrays.asList(src.getSimpleName(), dst.getSimpleName(), fn); 418 return fn; 419 } 420 421 static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) { 422 MethodType type = target.type(); 423 int last = type.parameterCount() - 1; 424 if (type.parameterType(last) != arrayType) 425 target = target.asType(type.changeParameterType(last, arrayType)); 426 target = target.asFixedArity(); // make sure this attribute is turned off 427 return new AsVarargsCollector(target, arrayType); 428 } 429 430 private static final class AsVarargsCollector extends DelegatingMethodHandle { 431 private final MethodHandle target; 432 private final Class<?> arrayType; 433 private @Stable MethodHandle asCollectorCache; 434 435 AsVarargsCollector(MethodHandle target, Class<?> arrayType) { 436 this(target.type(), target, arrayType); 437 } 438 AsVarargsCollector(MethodType type, MethodHandle target, Class<?> arrayType) { 439 super(type, target); 440 this.target = target; 441 this.arrayType = arrayType; 442 this.asCollectorCache = target.asCollector(arrayType, 0); 443 } 444 445 @Override 446 public boolean isVarargsCollector() { 447 return true; 448 } 449 450 @Override 451 protected MethodHandle getTarget() { 452 return target; 453 } 454 455 @Override 456 public MethodHandle asFixedArity() { 457 return target; 458 } 459 460 @Override 461 MethodHandle setVarargs(MemberName member) { 462 if (member.isVarargs()) return this; 463 return asFixedArity(); 464 } 465 466 @Override 467 public MethodHandle asTypeUncached(MethodType newType) { 468 MethodType type = this.type(); 469 int collectArg = type.parameterCount() - 1; 470 int newArity = newType.parameterCount(); 471 if (newArity == collectArg+1 && 472 type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) { 473 // if arity and trailing parameter are compatible, do normal thing 474 return asTypeCache = asFixedArity().asType(newType); 475 } 476 // check cache 477 MethodHandle acc = asCollectorCache; 478 if (acc != null && acc.type().parameterCount() == newArity) 479 return asTypeCache = acc.asType(newType); 480 // build and cache a collector 481 int arrayLength = newArity - collectArg; 482 MethodHandle collector; 483 try { 484 collector = asFixedArity().asCollector(arrayType, arrayLength); 485 assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector; 486 } catch (IllegalArgumentException ex) { 487 throw new WrongMethodTypeException("cannot build collector", ex); 488 } 489 asCollectorCache = collector; 490 return asTypeCache = collector.asType(newType); 491 } 492 493 @Override 494 boolean viewAsTypeChecks(MethodType newType, boolean strict) { 495 super.viewAsTypeChecks(newType, true); 496 if (strict) return true; 497 // extra assertion for non-strict checks: 498 assert (type().lastParameterType().getComponentType() 499 .isAssignableFrom( 500 newType.lastParameterType().getComponentType())) 501 : Arrays.asList(this, newType); 502 return true; 503 } 504 } 505 506 /** Factory method: Spread selected argument. */ 507 static MethodHandle makeSpreadArguments(MethodHandle target, 508 Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) { 509 MethodType targetType = target.type(); 510 511 for (int i = 0; i < spreadArgCount; i++) { 512 Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i); 513 if (arg == null) arg = Object.class; 514 targetType = targetType.changeParameterType(spreadArgPos + i, arg); 515 } 516 target = target.asType(targetType); 517 518 MethodType srcType = targetType 519 .replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType); 520 // Now build a LambdaForm. 521 MethodType lambdaType = srcType.invokerType(); 522 Name[] names = arguments(spreadArgCount + 2, lambdaType); 523 int nameCursor = lambdaType.parameterCount(); 524 int[] indexes = new int[targetType.parameterCount()]; 525 526 for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) { 527 Class<?> src = lambdaType.parameterType(i); 528 if (i == spreadArgPos) { 529 // Spread the array. 530 MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType); 531 Name array = names[argIndex]; 532 names[nameCursor++] = new Name(Lazy.NF_checkSpreadArgument, array, spreadArgCount); 533 for (int j = 0; j < spreadArgCount; i++, j++) { 534 indexes[i] = nameCursor; 535 names[nameCursor++] = new Name(aload, array, j); 536 } 537 } else if (i < indexes.length) { 538 indexes[i] = argIndex; 539 } 540 } 541 assert(nameCursor == names.length-1); // leave room for the final call 542 543 // Build argument array for the call. 544 Name[] targetArgs = new Name[targetType.parameterCount()]; 545 for (int i = 0; i < targetType.parameterCount(); i++) { 546 int idx = indexes[i]; 547 targetArgs[i] = names[idx]; 548 } 549 names[names.length - 1] = new Name(target, (Object[]) targetArgs); 550 551 LambdaForm form = new LambdaForm("spread", lambdaType.parameterCount(), names); 552 return SimpleMethodHandle.make(srcType, form); 553 } 554 555 static void checkSpreadArgument(Object av, int n) { 556 if (av == null) { 557 if (n == 0) return; 558 } else if (av instanceof Object[]) { 559 int len = ((Object[])av).length; 560 if (len == n) return; 561 } else { 562 int len = java.lang.reflect.Array.getLength(av); 563 if (len == n) return; 564 } 565 // fall through to error: 566 throw newIllegalArgumentException("array is not of length "+n); 567 } 568 569 /** 570 * Pre-initialized NamedFunctions for bootstrapping purposes. 571 * Factored in an inner class to delay initialization until first usage. 572 */ 573 static class Lazy { 574 private static final Class<?> MHI = MethodHandleImpl.class; 575 private static final Class<?> CLS = Class.class; 576 577 private static final MethodHandle[] ARRAYS; 578 private static final MethodHandle[] FILL_ARRAYS; 579 580 static final NamedFunction NF_checkSpreadArgument; 581 static final NamedFunction NF_guardWithCatch; 582 static final NamedFunction NF_throwException; 583 static final NamedFunction NF_profileBoolean; 584 585 static final MethodHandle MH_cast; 586 static final MethodHandle MH_selectAlternative; 587 static final MethodHandle MH_copyAsPrimitiveArray; 588 static final MethodHandle MH_fillNewTypedArray; 589 static final MethodHandle MH_fillNewArray; 590 static final MethodHandle MH_arrayIdentity; 591 592 static { 593 ARRAYS = makeArrays(); 594 FILL_ARRAYS = makeFillArrays(); 595 596 try { 597 NF_checkSpreadArgument = new NamedFunction(MHI.getDeclaredMethod("checkSpreadArgument", Object.class, int.class)); 598 NF_guardWithCatch = new NamedFunction(MHI.getDeclaredMethod("guardWithCatch", MethodHandle.class, Class.class, 599 MethodHandle.class, Object[].class)); 600 NF_throwException = new NamedFunction(MHI.getDeclaredMethod("throwException", Throwable.class)); 601 NF_profileBoolean = new NamedFunction(MHI.getDeclaredMethod("profileBoolean", boolean.class, int[].class)); 602 603 NF_checkSpreadArgument.resolve(); 604 NF_guardWithCatch.resolve(); 605 NF_throwException.resolve(); 606 NF_profileBoolean.resolve(); 607 608 MH_cast = IMPL_LOOKUP.findVirtual(CLS, "cast", 609 MethodType.methodType(Object.class, Object.class)); 610 MH_copyAsPrimitiveArray = IMPL_LOOKUP.findStatic(MHI, "copyAsPrimitiveArray", 611 MethodType.methodType(Object.class, Wrapper.class, Object[].class)); 612 MH_arrayIdentity = IMPL_LOOKUP.findStatic(MHI, "identity", 613 MethodType.methodType(Object[].class, Object[].class)); 614 MH_fillNewArray = IMPL_LOOKUP.findStatic(MHI, "fillNewArray", 615 MethodType.methodType(Object[].class, Integer.class, Object[].class)); 616 MH_fillNewTypedArray = IMPL_LOOKUP.findStatic(MHI, "fillNewTypedArray", 617 MethodType.methodType(Object[].class, Object[].class, Integer.class, Object[].class)); 618 619 MH_selectAlternative = makeIntrinsic( 620 IMPL_LOOKUP.findStatic(MHI, "selectAlternative", 621 MethodType.methodType(MethodHandle.class, boolean.class, MethodHandle.class, MethodHandle.class)), 622 Intrinsic.SELECT_ALTERNATIVE); 623 } catch (ReflectiveOperationException ex) { 624 throw newInternalError(ex); 625 } 626 } 627 } 628 629 /** Factory method: Collect or filter selected argument(s). */ 630 static MethodHandle makeCollectArguments(MethodHandle target, 631 MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) { 632 MethodType targetType = target.type(); // (a..., c, [b...])=>r 633 MethodType collectorType = collector.type(); // (b...)=>c 634 int collectArgCount = collectorType.parameterCount(); 635 Class<?> collectValType = collectorType.returnType(); 636 int collectValCount = (collectValType == void.class ? 0 : 1); 637 MethodType srcType = targetType // (a..., [b...])=>r 638 .dropParameterTypes(collectArgPos, collectArgPos+collectValCount); 639 if (!retainOriginalArgs) { // (a..., b...)=>r 640 srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterList()); 641 } 642 // in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ] 643 // out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ] 644 // out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ] 645 646 // Now build a LambdaForm. 647 MethodType lambdaType = srcType.invokerType(); 648 Name[] names = arguments(2, lambdaType); 649 final int collectNamePos = names.length - 2; 650 final int targetNamePos = names.length - 1; 651 652 Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount); 653 names[collectNamePos] = new Name(collector, (Object[]) collectorArgs); 654 655 // Build argument array for the target. 656 // Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ]. 657 // Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ]. 658 Name[] targetArgs = new Name[targetType.parameterCount()]; 659 int inputArgPos = 1; // incoming LF args to copy to target 660 int targetArgPos = 0; // fill pointer for targetArgs 661 int chunk = collectArgPos; // |headArgs| 662 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk); 663 inputArgPos += chunk; 664 targetArgPos += chunk; 665 if (collectValType != void.class) { 666 targetArgs[targetArgPos++] = names[collectNamePos]; 667 } 668 chunk = collectArgCount; 669 if (retainOriginalArgs) { 670 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk); 671 targetArgPos += chunk; // optionally pass on the collected chunk 672 } 673 inputArgPos += chunk; 674 chunk = targetArgs.length - targetArgPos; // all the rest 675 System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk); 676 assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also 677 names[targetNamePos] = new Name(target, (Object[]) targetArgs); 678 679 LambdaForm form = new LambdaForm("collect", lambdaType.parameterCount(), names); 680 return SimpleMethodHandle.make(srcType, form); 681 } 682 683 @LambdaForm.Hidden 684 static 685 MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) { 686 if (testResult) { 687 return target; 688 } else { 689 return fallback; 690 } 691 } 692 693 // Intrinsified by C2. Counters are used during parsing to calculate branch frequencies. 694 @LambdaForm.Hidden 695 @jdk.internal.HotSpotIntrinsicCandidate 696 static 697 boolean profileBoolean(boolean result, int[] counters) { 698 // Profile is int[2] where [0] and [1] correspond to false and true occurrences respectively. 699 int idx = result ? 1 : 0; 700 try { 701 counters[idx] = Math.addExact(counters[idx], 1); 702 } catch (ArithmeticException e) { 703 // Avoid continuous overflow by halving the problematic count. 704 counters[idx] = counters[idx] / 2; 705 } 706 return result; 707 } 708 709 // Intrinsified by C2. Returns true if obj is a compile-time constant. 710 @LambdaForm.Hidden 711 @jdk.internal.HotSpotIntrinsicCandidate 712 static 713 boolean isCompileConstant(Object obj) { 714 return false; 715 } 716 717 static 718 MethodHandle makeGuardWithTest(MethodHandle test, 719 MethodHandle target, 720 MethodHandle fallback) { 721 MethodType type = target.type(); 722 assert(test.type().equals(type.changeReturnType(boolean.class)) && fallback.type().equals(type)); 723 MethodType basicType = type.basicType(); 724 LambdaForm form = makeGuardWithTestForm(basicType); 725 BoundMethodHandle mh; 726 try { 727 if (PROFILE_GWT) { 728 int[] counts = new int[2]; 729 mh = (BoundMethodHandle) 730 BoundMethodHandle.speciesData_LLLL().constructor().invokeBasic(type, form, 731 (Object) test, (Object) profile(target), (Object) profile(fallback), counts); 732 } else { 733 mh = (BoundMethodHandle) 734 BoundMethodHandle.speciesData_LLL().constructor().invokeBasic(type, form, 735 (Object) test, (Object) profile(target), (Object) profile(fallback)); 736 } 737 } catch (Throwable ex) { 738 throw uncaughtException(ex); 739 } 740 assert(mh.type() == type); 741 return mh; 742 } 743 744 745 static 746 MethodHandle profile(MethodHandle target) { 747 if (DONT_INLINE_THRESHOLD >= 0) { 748 return makeBlockInliningWrapper(target); 749 } else { 750 return target; 751 } 752 } 753 754 /** 755 * Block inlining during JIT-compilation of a target method handle if it hasn't been invoked enough times. 756 * Corresponding LambdaForm has @DontInline when compiled into bytecode. 757 */ 758 static 759 MethodHandle makeBlockInliningWrapper(MethodHandle target) { 760 LambdaForm lform; 761 if (DONT_INLINE_THRESHOLD > 0) { 762 lform = PRODUCE_BLOCK_INLINING_FORM.apply(target); 763 } else { 764 lform = PRODUCE_REINVOKER_FORM.apply(target); 765 } 766 return new CountingWrapper(target, lform, 767 PRODUCE_BLOCK_INLINING_FORM, PRODUCE_REINVOKER_FORM, 768 DONT_INLINE_THRESHOLD); 769 } 770 771 /** Constructs reinvoker lambda form which block inlining during JIT-compilation for a particular method handle */ 772 private static final Function<MethodHandle, LambdaForm> PRODUCE_BLOCK_INLINING_FORM = new Function<MethodHandle, LambdaForm>() { 773 @Override 774 public LambdaForm apply(MethodHandle target) { 775 return DelegatingMethodHandle.makeReinvokerForm(target, 776 MethodTypeForm.LF_DELEGATE_BLOCK_INLINING, CountingWrapper.class, "reinvoker.dontInline", false, 777 DelegatingMethodHandle.NF_getTarget, CountingWrapper.NF_maybeStopCounting); 778 } 779 }; 780 781 /** Constructs simple reinvoker lambda form for a particular method handle */ 782 private static final Function<MethodHandle, LambdaForm> PRODUCE_REINVOKER_FORM = new Function<MethodHandle, LambdaForm>() { 783 @Override 784 public LambdaForm apply(MethodHandle target) { 785 return DelegatingMethodHandle.makeReinvokerForm(target, 786 MethodTypeForm.LF_DELEGATE, DelegatingMethodHandle.class, DelegatingMethodHandle.NF_getTarget); 787 } 788 }; 789 790 /** 791 * Counting method handle. It has 2 states: counting and non-counting. 792 * It is in counting state for the first n invocations and then transitions to non-counting state. 793 * Behavior in counting and non-counting states is determined by lambda forms produced by 794 * countingFormProducer & nonCountingFormProducer respectively. 795 */ 796 static class CountingWrapper extends DelegatingMethodHandle { 797 private final MethodHandle target; 798 private int count; 799 private Function<MethodHandle, LambdaForm> countingFormProducer; 800 private Function<MethodHandle, LambdaForm> nonCountingFormProducer; 801 private volatile boolean isCounting; 802 803 private CountingWrapper(MethodHandle target, LambdaForm lform, 804 Function<MethodHandle, LambdaForm> countingFromProducer, 805 Function<MethodHandle, LambdaForm> nonCountingFormProducer, 806 int count) { 807 super(target.type(), lform); 808 this.target = target; 809 this.count = count; 810 this.countingFormProducer = countingFromProducer; 811 this.nonCountingFormProducer = nonCountingFormProducer; 812 this.isCounting = (count > 0); 813 } 814 815 @Hidden 816 @Override 817 protected MethodHandle getTarget() { 818 return target; 819 } 820 821 @Override 822 public MethodHandle asTypeUncached(MethodType newType) { 823 MethodHandle newTarget = target.asType(newType); 824 MethodHandle wrapper; 825 if (isCounting) { 826 LambdaForm lform; 827 lform = countingFormProducer.apply(newTarget); 828 wrapper = new CountingWrapper(newTarget, lform, countingFormProducer, nonCountingFormProducer, DONT_INLINE_THRESHOLD); 829 } else { 830 wrapper = newTarget; // no need for a counting wrapper anymore 831 } 832 return (asTypeCache = wrapper); 833 } 834 835 boolean countDown() { 836 int c = count; 837 if (c <= 1) { 838 // Try to limit number of updates. MethodHandle.updateForm() doesn't guarantee LF update visibility. 839 if (isCounting) { 840 isCounting = false; 841 return true; 842 } else { 843 return false; 844 } 845 } else { 846 count = c - 1; 847 return false; 848 } 849 } 850 851 @Hidden 852 static void maybeStopCounting(Object o1) { 853 CountingWrapper wrapper = (CountingWrapper) o1; 854 if (wrapper.countDown()) { 855 // Reached invocation threshold. Replace counting behavior with a non-counting one. 856 LambdaForm lform = wrapper.nonCountingFormProducer.apply(wrapper.target); 857 lform.compileToBytecode(); // speed up warmup by avoiding LF interpretation again after transition 858 wrapper.updateForm(lform); 859 } 860 } 861 862 static final NamedFunction NF_maybeStopCounting; 863 static { 864 Class<?> THIS_CLASS = CountingWrapper.class; 865 try { 866 NF_maybeStopCounting = new NamedFunction(THIS_CLASS.getDeclaredMethod("maybeStopCounting", Object.class)); 867 } catch (ReflectiveOperationException ex) { 868 throw newInternalError(ex); 869 } 870 } 871 } 872 873 static 874 LambdaForm makeGuardWithTestForm(MethodType basicType) { 875 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWT); 876 if (lform != null) return lform; 877 final int THIS_MH = 0; // the BMH_LLL 878 final int ARG_BASE = 1; // start of incoming arguments 879 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount(); 880 int nameCursor = ARG_LIMIT; 881 final int GET_TEST = nameCursor++; 882 final int GET_TARGET = nameCursor++; 883 final int GET_FALLBACK = nameCursor++; 884 final int GET_COUNTERS = PROFILE_GWT ? nameCursor++ : -1; 885 final int CALL_TEST = nameCursor++; 886 final int PROFILE = (GET_COUNTERS != -1) ? nameCursor++ : -1; 887 final int TEST = nameCursor-1; // previous statement: either PROFILE or CALL_TEST 888 final int SELECT_ALT = nameCursor++; 889 final int CALL_TARGET = nameCursor++; 890 assert(CALL_TARGET == SELECT_ALT+1); // must be true to trigger IBG.emitSelectAlternative 891 892 MethodType lambdaType = basicType.invokerType(); 893 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType); 894 895 BoundMethodHandle.SpeciesData data = 896 (GET_COUNTERS != -1) ? BoundMethodHandle.speciesData_LLLL() 897 : BoundMethodHandle.speciesData_LLL(); 898 names[THIS_MH] = names[THIS_MH].withConstraint(data); 899 names[GET_TEST] = new Name(data.getterFunction(0), names[THIS_MH]); 900 names[GET_TARGET] = new Name(data.getterFunction(1), names[THIS_MH]); 901 names[GET_FALLBACK] = new Name(data.getterFunction(2), names[THIS_MH]); 902 if (GET_COUNTERS != -1) { 903 names[GET_COUNTERS] = new Name(data.getterFunction(3), names[THIS_MH]); 904 } 905 Object[] invokeArgs = Arrays.copyOfRange(names, 0, ARG_LIMIT, Object[].class); 906 907 // call test 908 MethodType testType = basicType.changeReturnType(boolean.class).basicType(); 909 invokeArgs[0] = names[GET_TEST]; 910 names[CALL_TEST] = new Name(testType, invokeArgs); 911 912 // profile branch 913 if (PROFILE != -1) { 914 names[PROFILE] = new Name(Lazy.NF_profileBoolean, names[CALL_TEST], names[GET_COUNTERS]); 915 } 916 // call selectAlternative 917 names[SELECT_ALT] = new Name(Lazy.MH_selectAlternative, names[TEST], names[GET_TARGET], names[GET_FALLBACK]); 918 919 // call target or fallback 920 invokeArgs[0] = names[SELECT_ALT]; 921 names[CALL_TARGET] = new Name(basicType, invokeArgs); 922 923 lform = new LambdaForm("guard", lambdaType.parameterCount(), names, /*forceInline=*/true); 924 925 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWT, lform); 926 } 927 928 /** 929 * The LambdaForm shape for catchException combinator is the following: 930 * <blockquote><pre>{@code 931 * guardWithCatch=Lambda(a0:L,a1:L,a2:L)=>{ 932 * t3:L=BoundMethodHandle$Species_LLLLL.argL0(a0:L); 933 * t4:L=BoundMethodHandle$Species_LLLLL.argL1(a0:L); 934 * t5:L=BoundMethodHandle$Species_LLLLL.argL2(a0:L); 935 * t6:L=BoundMethodHandle$Species_LLLLL.argL3(a0:L); 936 * t7:L=BoundMethodHandle$Species_LLLLL.argL4(a0:L); 937 * t8:L=MethodHandle.invokeBasic(t6:L,a1:L,a2:L); 938 * t9:L=MethodHandleImpl.guardWithCatch(t3:L,t4:L,t5:L,t8:L); 939 * t10:I=MethodHandle.invokeBasic(t7:L,t9:L);t10:I} 940 * }</pre></blockquote> 941 * 942 * argL0 and argL2 are target and catcher method handles. argL1 is exception class. 943 * argL3 and argL4 are auxiliary method handles: argL3 boxes arguments and wraps them into Object[] 944 * (ValueConversions.array()) and argL4 unboxes result if necessary (ValueConversions.unbox()). 945 * 946 * Having t8 and t10 passed outside and not hardcoded into a lambda form allows to share lambda forms 947 * among catchException combinators with the same basic type. 948 */ 949 private static LambdaForm makeGuardWithCatchForm(MethodType basicType) { 950 MethodType lambdaType = basicType.invokerType(); 951 952 LambdaForm lform = basicType.form().cachedLambdaForm(MethodTypeForm.LF_GWC); 953 if (lform != null) { 954 return lform; 955 } 956 final int THIS_MH = 0; // the BMH_LLLLL 957 final int ARG_BASE = 1; // start of incoming arguments 958 final int ARG_LIMIT = ARG_BASE + basicType.parameterCount(); 959 960 int nameCursor = ARG_LIMIT; 961 final int GET_TARGET = nameCursor++; 962 final int GET_CLASS = nameCursor++; 963 final int GET_CATCHER = nameCursor++; 964 final int GET_COLLECT_ARGS = nameCursor++; 965 final int GET_UNBOX_RESULT = nameCursor++; 966 final int BOXED_ARGS = nameCursor++; 967 final int TRY_CATCH = nameCursor++; 968 final int UNBOX_RESULT = nameCursor++; 969 970 Name[] names = arguments(nameCursor - ARG_LIMIT, lambdaType); 971 972 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL(); 973 names[THIS_MH] = names[THIS_MH].withConstraint(data); 974 names[GET_TARGET] = new Name(data.getterFunction(0), names[THIS_MH]); 975 names[GET_CLASS] = new Name(data.getterFunction(1), names[THIS_MH]); 976 names[GET_CATCHER] = new Name(data.getterFunction(2), names[THIS_MH]); 977 names[GET_COLLECT_ARGS] = new Name(data.getterFunction(3), names[THIS_MH]); 978 names[GET_UNBOX_RESULT] = new Name(data.getterFunction(4), names[THIS_MH]); 979 980 // FIXME: rework argument boxing/result unboxing logic for LF interpretation 981 982 // t_{i}:L=MethodHandle.invokeBasic(collectArgs:L,a1:L,...); 983 MethodType collectArgsType = basicType.changeReturnType(Object.class); 984 MethodHandle invokeBasic = MethodHandles.basicInvoker(collectArgsType); 985 Object[] args = new Object[invokeBasic.type().parameterCount()]; 986 args[0] = names[GET_COLLECT_ARGS]; 987 System.arraycopy(names, ARG_BASE, args, 1, ARG_LIMIT-ARG_BASE); 988 names[BOXED_ARGS] = new Name(makeIntrinsic(invokeBasic, Intrinsic.GUARD_WITH_CATCH), args); 989 990 // t_{i+1}:L=MethodHandleImpl.guardWithCatch(target:L,exType:L,catcher:L,t_{i}:L); 991 Object[] gwcArgs = new Object[] {names[GET_TARGET], names[GET_CLASS], names[GET_CATCHER], names[BOXED_ARGS]}; 992 names[TRY_CATCH] = new Name(Lazy.NF_guardWithCatch, gwcArgs); 993 994 // t_{i+2}:I=MethodHandle.invokeBasic(unbox:L,t_{i+1}:L); 995 MethodHandle invokeBasicUnbox = MethodHandles.basicInvoker(MethodType.methodType(basicType.rtype(), Object.class)); 996 Object[] unboxArgs = new Object[] {names[GET_UNBOX_RESULT], names[TRY_CATCH]}; 997 names[UNBOX_RESULT] = new Name(invokeBasicUnbox, unboxArgs); 998 999 lform = new LambdaForm("guardWithCatch", lambdaType.parameterCount(), names); 1000 1001 return basicType.form().setCachedLambdaForm(MethodTypeForm.LF_GWC, lform); 1002 } 1003 1004 static 1005 MethodHandle makeGuardWithCatch(MethodHandle target, 1006 Class<? extends Throwable> exType, 1007 MethodHandle catcher) { 1008 MethodType type = target.type(); 1009 LambdaForm form = makeGuardWithCatchForm(type.basicType()); 1010 1011 // Prepare auxiliary method handles used during LambdaForm interpretation. 1012 // Box arguments and wrap them into Object[]: ValueConversions.array(). 1013 MethodType varargsType = type.changeReturnType(Object[].class); 1014 MethodHandle collectArgs = varargsArray(type.parameterCount()).asType(varargsType); 1015 // Result unboxing: ValueConversions.unbox() OR ValueConversions.identity() OR ValueConversions.ignore(). 1016 MethodHandle unboxResult; 1017 Class<?> rtype = type.returnType(); 1018 if (rtype.isPrimitive()) { 1019 if (rtype == void.class) { 1020 unboxResult = ValueConversions.ignore(); 1021 } else { 1022 Wrapper w = Wrapper.forPrimitiveType(type.returnType()); 1023 unboxResult = ValueConversions.unboxExact(w); 1024 } 1025 } else { 1026 unboxResult = MethodHandles.identity(Object.class); 1027 } 1028 1029 BoundMethodHandle.SpeciesData data = BoundMethodHandle.speciesData_LLLLL(); 1030 BoundMethodHandle mh; 1031 try { 1032 mh = (BoundMethodHandle) 1033 data.constructor().invokeBasic(type, form, (Object) target, (Object) exType, (Object) catcher, 1034 (Object) collectArgs, (Object) unboxResult); 1035 } catch (Throwable ex) { 1036 throw uncaughtException(ex); 1037 } 1038 assert(mh.type() == type); 1039 return mh; 1040 } 1041 1042 /** 1043 * Intrinsified during LambdaForm compilation 1044 * (see {@link InvokerBytecodeGenerator#emitGuardWithCatch emitGuardWithCatch}). 1045 */ 1046 @LambdaForm.Hidden 1047 static Object guardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher, 1048 Object... av) throws Throwable { 1049 // Use asFixedArity() to avoid unnecessary boxing of last argument for VarargsCollector case. 1050 try { 1051 return target.asFixedArity().invokeWithArguments(av); 1052 } catch (Throwable t) { 1053 if (!exType.isInstance(t)) throw t; 1054 return catcher.asFixedArity().invokeWithArguments(prepend(t, av)); 1055 } 1056 } 1057 1058 /** Prepend an element {@code elem} to an {@code array}. */ 1059 @LambdaForm.Hidden 1060 private static Object[] prepend(Object elem, Object[] array) { 1061 Object[] newArray = new Object[array.length+1]; 1062 newArray[0] = elem; 1063 System.arraycopy(array, 0, newArray, 1, array.length); 1064 return newArray; 1065 } 1066 1067 static 1068 MethodHandle throwException(MethodType type) { 1069 assert(Throwable.class.isAssignableFrom(type.parameterType(0))); 1070 int arity = type.parameterCount(); 1071 if (arity > 1) { 1072 MethodHandle mh = throwException(type.dropParameterTypes(1, arity)); 1073 mh = MethodHandles.dropArguments(mh, 1, type.parameterList().subList(1, arity)); 1074 return mh; 1075 } 1076 return makePairwiseConvert(Lazy.NF_throwException.resolvedHandle(), type, false, true); 1077 } 1078 1079 static <T extends Throwable> Empty throwException(T t) throws T { throw t; } 1080 1081 static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2]; 1082 static MethodHandle fakeMethodHandleInvoke(MemberName method) { 1083 int idx; 1084 assert(method.isMethodHandleInvoke()); 1085 switch (method.getName()) { 1086 case "invoke": idx = 0; break; 1087 case "invokeExact": idx = 1; break; 1088 default: throw new InternalError(method.getName()); 1089 } 1090 MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx]; 1091 if (mh != null) return mh; 1092 MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class, 1093 MethodHandle.class, Object[].class); 1094 mh = throwException(type); 1095 mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle")); 1096 if (!method.getInvocationType().equals(mh.type())) 1097 throw new InternalError(method.toString()); 1098 mh = mh.withInternalMemberName(method, false); 1099 mh = mh.asVarargsCollector(Object[].class); 1100 assert(method.isVarargs()); 1101 FAKE_METHOD_HANDLE_INVOKE[idx] = mh; 1102 return mh; 1103 } 1104 1105 /** 1106 * Create an alias for the method handle which, when called, 1107 * appears to be called from the same class loader and protection domain 1108 * as hostClass. 1109 * This is an expensive no-op unless the method which is called 1110 * is sensitive to its caller. A small number of system methods 1111 * are in this category, including Class.forName and Method.invoke. 1112 */ 1113 static 1114 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) { 1115 return BindCaller.bindCaller(mh, hostClass); 1116 } 1117 1118 // Put the whole mess into its own nested class. 1119 // That way we can lazily load the code and set up the constants. 1120 private static class BindCaller { 1121 static 1122 MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) { 1123 // Do not use this function to inject calls into system classes. 1124 if (hostClass == null 1125 || (hostClass.isArray() || 1126 hostClass.isPrimitive() || 1127 hostClass.getName().startsWith("java.") || 1128 hostClass.getName().startsWith("sun."))) { 1129 throw new InternalError(); // does not happen, and should not anyway 1130 } 1131 // For simplicity, convert mh to a varargs-like method. 1132 MethodHandle vamh = prepareForInvoker(mh); 1133 // Cache the result of makeInjectedInvoker once per argument class. 1134 MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass); 1135 return restoreToType(bccInvoker.bindTo(vamh), mh, hostClass); 1136 } 1137 1138 private static MethodHandle makeInjectedInvoker(Class<?> hostClass) { 1139 Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null); 1140 if (hostClass.getClassLoader() != bcc.getClassLoader()) 1141 throw new InternalError(hostClass.getName()+" (CL)"); 1142 try { 1143 if (hostClass.getProtectionDomain() != bcc.getProtectionDomain()) 1144 throw new InternalError(hostClass.getName()+" (PD)"); 1145 } catch (SecurityException ex) { 1146 // Self-check was blocked by security manager. This is OK. 1147 // In fact the whole try body could be turned into an assertion. 1148 } 1149 try { 1150 MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class)); 1151 init.invokeExact(); // force initialization of the class 1152 } catch (Throwable ex) { 1153 throw uncaughtException(ex); 1154 } 1155 MethodHandle bccInvoker; 1156 try { 1157 MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class); 1158 bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT); 1159 } catch (ReflectiveOperationException ex) { 1160 throw uncaughtException(ex); 1161 } 1162 // Test the invoker, to ensure that it really injects into the right place. 1163 try { 1164 MethodHandle vamh = prepareForInvoker(MH_checkCallerClass); 1165 Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc}); 1166 } catch (Throwable ex) { 1167 throw new InternalError(ex); 1168 } 1169 return bccInvoker; 1170 } 1171 private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue<MethodHandle>() { 1172 @Override protected MethodHandle computeValue(Class<?> hostClass) { 1173 return makeInjectedInvoker(hostClass); 1174 } 1175 }; 1176 1177 // Adapt mh so that it can be called directly from an injected invoker: 1178 private static MethodHandle prepareForInvoker(MethodHandle mh) { 1179 mh = mh.asFixedArity(); 1180 MethodType mt = mh.type(); 1181 int arity = mt.parameterCount(); 1182 MethodHandle vamh = mh.asType(mt.generic()); 1183 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames 1184 vamh = vamh.asSpreader(Object[].class, arity); 1185 vamh.internalForm().compileToBytecode(); // eliminate LFI stack frames 1186 return vamh; 1187 } 1188 1189 // Undo the adapter effect of prepareForInvoker: 1190 private static MethodHandle restoreToType(MethodHandle vamh, 1191 MethodHandle original, 1192 Class<?> hostClass) { 1193 MethodType type = original.type(); 1194 MethodHandle mh = vamh.asCollector(Object[].class, type.parameterCount()); 1195 MemberName member = original.internalMemberName(); 1196 mh = mh.asType(type); 1197 mh = new WrappedMember(mh, type, member, original.isInvokeSpecial(), hostClass); 1198 return mh; 1199 } 1200 1201 private static final MethodHandle MH_checkCallerClass; 1202 static { 1203 final Class<?> THIS_CLASS = BindCaller.class; 1204 assert(checkCallerClass(THIS_CLASS, THIS_CLASS)); 1205 try { 1206 MH_checkCallerClass = IMPL_LOOKUP 1207 .findStatic(THIS_CLASS, "checkCallerClass", 1208 MethodType.methodType(boolean.class, Class.class, Class.class)); 1209 assert((boolean) MH_checkCallerClass.invokeExact(THIS_CLASS, THIS_CLASS)); 1210 } catch (Throwable ex) { 1211 throw new InternalError(ex); 1212 } 1213 } 1214 1215 @CallerSensitive 1216 private static boolean checkCallerClass(Class<?> expected, Class<?> expected2) { 1217 // This method is called via MH_checkCallerClass and so it's 1218 // correct to ask for the immediate caller here. 1219 Class<?> actual = Reflection.getCallerClass(); 1220 if (actual != expected && actual != expected2) 1221 throw new InternalError("found "+actual.getName()+", expected "+expected.getName() 1222 +(expected == expected2 ? "" : ", or else "+expected2.getName())); 1223 return true; 1224 } 1225 1226 private static final byte[] T_BYTES; 1227 static { 1228 final Object[] values = {null}; 1229 AccessController.doPrivileged(new PrivilegedAction<>() { 1230 public Void run() { 1231 try { 1232 Class<T> tClass = T.class; 1233 String tName = tClass.getName(); 1234 String tResource = tName.substring(tName.lastIndexOf('.')+1)+".class"; 1235 java.net.URLConnection uconn = tClass.getResource(tResource).openConnection(); 1236 int len = uconn.getContentLength(); 1237 byte[] bytes = new byte[len]; 1238 try (java.io.InputStream str = uconn.getInputStream()) { 1239 int nr = str.read(bytes); 1240 if (nr != len) throw new java.io.IOException(tResource); 1241 } 1242 values[0] = bytes; 1243 } catch (java.io.IOException ex) { 1244 throw new InternalError(ex); 1245 } 1246 return null; 1247 } 1248 }); 1249 T_BYTES = (byte[]) values[0]; 1250 } 1251 1252 // The following class is used as a template for Unsafe.defineAnonymousClass: 1253 private static class T { 1254 static void init() { } // side effect: initializes this class 1255 static Object invoke_V(MethodHandle vamh, Object[] args) throws Throwable { 1256 return vamh.invokeExact(args); 1257 } 1258 } 1259 } 1260 1261 1262 /** This subclass allows a wrapped method handle to be re-associated with an arbitrary member name. */ 1263 private static final class WrappedMember extends DelegatingMethodHandle { 1264 private final MethodHandle target; 1265 private final MemberName member; 1266 private final Class<?> callerClass; 1267 private final boolean isInvokeSpecial; 1268 1269 private WrappedMember(MethodHandle target, MethodType type, 1270 MemberName member, boolean isInvokeSpecial, 1271 Class<?> callerClass) { 1272 super(type, target); 1273 this.target = target; 1274 this.member = member; 1275 this.callerClass = callerClass; 1276 this.isInvokeSpecial = isInvokeSpecial; 1277 } 1278 1279 @Override 1280 MemberName internalMemberName() { 1281 return member; 1282 } 1283 @Override 1284 Class<?> internalCallerClass() { 1285 return callerClass; 1286 } 1287 @Override 1288 boolean isInvokeSpecial() { 1289 return isInvokeSpecial; 1290 } 1291 @Override 1292 protected MethodHandle getTarget() { 1293 return target; 1294 } 1295 @Override 1296 public MethodHandle asTypeUncached(MethodType newType) { 1297 // This MH is an alias for target, except for the MemberName 1298 // Drop the MemberName if there is any conversion. 1299 return asTypeCache = target.asType(newType); 1300 } 1301 } 1302 1303 static MethodHandle makeWrappedMember(MethodHandle target, MemberName member, boolean isInvokeSpecial) { 1304 if (member.equals(target.internalMemberName()) && isInvokeSpecial == target.isInvokeSpecial()) 1305 return target; 1306 return new WrappedMember(target, target.type(), member, isInvokeSpecial, null); 1307 } 1308 1309 /** Intrinsic IDs */ 1310 /*non-public*/ 1311 enum Intrinsic { 1312 SELECT_ALTERNATIVE, 1313 GUARD_WITH_CATCH, 1314 NEW_ARRAY, 1315 ARRAY_LOAD, 1316 ARRAY_STORE, 1317 IDENTITY, 1318 ZERO, 1319 NONE // no intrinsic associated 1320 } 1321 1322 /** Mark arbitrary method handle as intrinsic. 1323 * InvokerBytecodeGenerator uses this info to produce more efficient bytecode shape. */ 1324 private static final class IntrinsicMethodHandle extends DelegatingMethodHandle { 1325 private final MethodHandle target; 1326 private final Intrinsic intrinsicName; 1327 1328 IntrinsicMethodHandle(MethodHandle target, Intrinsic intrinsicName) { 1329 super(target.type(), target); 1330 this.target = target; 1331 this.intrinsicName = intrinsicName; 1332 } 1333 1334 @Override 1335 protected MethodHandle getTarget() { 1336 return target; 1337 } 1338 1339 @Override 1340 Intrinsic intrinsicName() { 1341 return intrinsicName; 1342 } 1343 1344 @Override 1345 public MethodHandle asTypeUncached(MethodType newType) { 1346 // This MH is an alias for target, except for the intrinsic name 1347 // Drop the name if there is any conversion. 1348 return asTypeCache = target.asType(newType); 1349 } 1350 1351 @Override 1352 String internalProperties() { 1353 return super.internalProperties() + 1354 "\n& Intrinsic="+intrinsicName; 1355 } 1356 1357 @Override 1358 public MethodHandle asCollector(Class<?> arrayType, int arrayLength) { 1359 if (intrinsicName == Intrinsic.IDENTITY) { 1360 MethodType resultType = type().asCollectorType(arrayType, arrayLength); 1361 MethodHandle newArray = MethodHandleImpl.varargsArray(arrayType, arrayLength); 1362 return newArray.asType(resultType); 1363 } 1364 return super.asCollector(arrayType, arrayLength); 1365 } 1366 } 1367 1368 static MethodHandle makeIntrinsic(MethodHandle target, Intrinsic intrinsicName) { 1369 if (intrinsicName == target.intrinsicName()) 1370 return target; 1371 return new IntrinsicMethodHandle(target, intrinsicName); 1372 } 1373 1374 static MethodHandle makeIntrinsic(MethodType type, LambdaForm form, Intrinsic intrinsicName) { 1375 return new IntrinsicMethodHandle(SimpleMethodHandle.make(type, form), intrinsicName); 1376 } 1377 1378 /// Collection of multiple arguments. 1379 1380 private static MethodHandle findCollector(String name, int nargs, Class<?> rtype, Class<?>... ptypes) { 1381 MethodType type = MethodType.genericMethodType(nargs) 1382 .changeReturnType(rtype) 1383 .insertParameterTypes(0, ptypes); 1384 try { 1385 return IMPL_LOOKUP.findStatic(MethodHandleImpl.class, name, type); 1386 } catch (ReflectiveOperationException ex) { 1387 return null; 1388 } 1389 } 1390 1391 private static final Object[] NO_ARGS_ARRAY = {}; 1392 private static Object[] makeArray(Object... args) { return args; } 1393 private static Object[] array() { return NO_ARGS_ARRAY; } 1394 private static Object[] array(Object a0) 1395 { return makeArray(a0); } 1396 private static Object[] array(Object a0, Object a1) 1397 { return makeArray(a0, a1); } 1398 private static Object[] array(Object a0, Object a1, Object a2) 1399 { return makeArray(a0, a1, a2); } 1400 private static Object[] array(Object a0, Object a1, Object a2, Object a3) 1401 { return makeArray(a0, a1, a2, a3); } 1402 private static Object[] array(Object a0, Object a1, Object a2, Object a3, 1403 Object a4) 1404 { return makeArray(a0, a1, a2, a3, a4); } 1405 private static Object[] array(Object a0, Object a1, Object a2, Object a3, 1406 Object a4, Object a5) 1407 { return makeArray(a0, a1, a2, a3, a4, a5); } 1408 private static Object[] array(Object a0, Object a1, Object a2, Object a3, 1409 Object a4, Object a5, Object a6) 1410 { return makeArray(a0, a1, a2, a3, a4, a5, a6); } 1411 private static Object[] array(Object a0, Object a1, Object a2, Object a3, 1412 Object a4, Object a5, Object a6, Object a7) 1413 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7); } 1414 private static Object[] array(Object a0, Object a1, Object a2, Object a3, 1415 Object a4, Object a5, Object a6, Object a7, 1416 Object a8) 1417 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8); } 1418 private static Object[] array(Object a0, Object a1, Object a2, Object a3, 1419 Object a4, Object a5, Object a6, Object a7, 1420 Object a8, Object a9) 1421 { return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); } 1422 1423 private static final int ARRAYS_COUNT = 11; 1424 1425 private static MethodHandle[] makeArrays() { 1426 MethodHandle[] mhs = new MethodHandle[MAX_ARITY + 1]; 1427 for (int i = 0; i < ARRAYS_COUNT; i++) { 1428 MethodHandle mh = findCollector("array", i, Object[].class); 1429 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY); 1430 mhs[i] = mh; 1431 } 1432 assert(assertArrayMethodCount(mhs)); 1433 return mhs; 1434 } 1435 1436 private static boolean assertArrayMethodCount(MethodHandle[] mhs) { 1437 assert(findCollector("array", ARRAYS_COUNT, Object[].class) == null); 1438 for (int i = 0; i < ARRAYS_COUNT; i++) { 1439 assert(mhs[i] != null); 1440 } 1441 return true; 1442 } 1443 1444 // filling versions of the above: 1445 // using Integer len instead of int len and no varargs to avoid bootstrapping problems 1446 private static Object[] fillNewArray(Integer len, Object[] /*not ...*/ args) { 1447 Object[] a = new Object[len]; 1448 fillWithArguments(a, 0, args); 1449 return a; 1450 } 1451 private static Object[] fillNewTypedArray(Object[] example, Integer len, Object[] /*not ...*/ args) { 1452 Object[] a = Arrays.copyOf(example, len); 1453 assert(a.getClass() != Object[].class); 1454 fillWithArguments(a, 0, args); 1455 return a; 1456 } 1457 private static void fillWithArguments(Object[] a, int pos, Object... args) { 1458 System.arraycopy(args, 0, a, pos, args.length); 1459 } 1460 // using Integer pos instead of int pos to avoid bootstrapping problems 1461 private static Object[] fillArray(Integer pos, Object[] a, Object a0) 1462 { fillWithArguments(a, pos, a0); return a; } 1463 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1) 1464 { fillWithArguments(a, pos, a0, a1); return a; } 1465 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2) 1466 { fillWithArguments(a, pos, a0, a1, a2); return a; } 1467 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3) 1468 { fillWithArguments(a, pos, a0, a1, a2, a3); return a; } 1469 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3, 1470 Object a4) 1471 { fillWithArguments(a, pos, a0, a1, a2, a3, a4); return a; } 1472 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3, 1473 Object a4, Object a5) 1474 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5); return a; } 1475 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3, 1476 Object a4, Object a5, Object a6) 1477 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6); return a; } 1478 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3, 1479 Object a4, Object a5, Object a6, Object a7) 1480 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7); return a; } 1481 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3, 1482 Object a4, Object a5, Object a6, Object a7, 1483 Object a8) 1484 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8); return a; } 1485 private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3, 1486 Object a4, Object a5, Object a6, Object a7, 1487 Object a8, Object a9) 1488 { fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); return a; } 1489 1490 private static final int FILL_ARRAYS_COUNT = 11; // current number of fillArray methods 1491 1492 private static MethodHandle[] makeFillArrays() { 1493 MethodHandle[] mhs = new MethodHandle[FILL_ARRAYS_COUNT]; 1494 mhs[0] = null; // there is no empty fill; at least a0 is required 1495 for (int i = 1; i < FILL_ARRAYS_COUNT; i++) { 1496 MethodHandle mh = findCollector("fillArray", i, Object[].class, Integer.class, Object[].class); 1497 mhs[i] = mh; 1498 } 1499 assert(assertFillArrayMethodCount(mhs)); 1500 return mhs; 1501 } 1502 1503 private static boolean assertFillArrayMethodCount(MethodHandle[] mhs) { 1504 assert(findCollector("fillArray", FILL_ARRAYS_COUNT, Object[].class, Integer.class, Object[].class) == null); 1505 for (int i = 1; i < FILL_ARRAYS_COUNT; i++) { 1506 assert(mhs[i] != null); 1507 } 1508 return true; 1509 } 1510 1511 private static Object copyAsPrimitiveArray(Wrapper w, Object... boxes) { 1512 Object a = w.makeArray(boxes.length); 1513 w.copyArrayUnboxing(boxes, 0, a, 0, boxes.length); 1514 return a; 1515 } 1516 1517 /** Return a method handle that takes the indicated number of Object 1518 * arguments and returns an Object array of them, as if for varargs. 1519 */ 1520 static MethodHandle varargsArray(int nargs) { 1521 MethodHandle mh = Lazy.ARRAYS[nargs]; 1522 if (mh != null) return mh; 1523 mh = buildVarargsArray(Lazy.MH_fillNewArray, Lazy.MH_arrayIdentity, nargs); 1524 assert(assertCorrectArity(mh, nargs)); 1525 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY); 1526 return Lazy.ARRAYS[nargs] = mh; 1527 } 1528 1529 private static boolean assertCorrectArity(MethodHandle mh, int arity) { 1530 assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh; 1531 return true; 1532 } 1533 1534 // Array identity function (used as Lazy.MH_arrayIdentity). 1535 static <T> T[] identity(T[] x) { 1536 return x; 1537 } 1538 1539 private static MethodHandle buildVarargsArray(MethodHandle newArray, MethodHandle finisher, int nargs) { 1540 // Build up the result mh as a sequence of fills like this: 1541 // finisher(fill(fill(newArrayWA(23,x1..x10),10,x11..x20),20,x21..x23)) 1542 // The various fill(_,10*I,___*[J]) are reusable. 1543 int leftLen = Math.min(nargs, LEFT_ARGS); // absorb some arguments immediately 1544 int rightLen = nargs - leftLen; 1545 MethodHandle leftCollector = newArray.bindTo(nargs); 1546 leftCollector = leftCollector.asCollector(Object[].class, leftLen); 1547 MethodHandle mh = finisher; 1548 if (rightLen > 0) { 1549 MethodHandle rightFiller = fillToRight(LEFT_ARGS + rightLen); 1550 if (mh == Lazy.MH_arrayIdentity) 1551 mh = rightFiller; 1552 else 1553 mh = MethodHandles.collectArguments(mh, 0, rightFiller); 1554 } 1555 if (mh == Lazy.MH_arrayIdentity) 1556 mh = leftCollector; 1557 else 1558 mh = MethodHandles.collectArguments(mh, 0, leftCollector); 1559 return mh; 1560 } 1561 1562 private static final int LEFT_ARGS = FILL_ARRAYS_COUNT - 1; 1563 private static final MethodHandle[] FILL_ARRAY_TO_RIGHT = new MethodHandle[MAX_ARITY+1]; 1564 /** fill_array_to_right(N).invoke(a, argL..arg[N-1]) 1565 * fills a[L]..a[N-1] with corresponding arguments, 1566 * and then returns a. The value L is a global constant (LEFT_ARGS). 1567 */ 1568 private static MethodHandle fillToRight(int nargs) { 1569 MethodHandle filler = FILL_ARRAY_TO_RIGHT[nargs]; 1570 if (filler != null) return filler; 1571 filler = buildFiller(nargs); 1572 assert(assertCorrectArity(filler, nargs - LEFT_ARGS + 1)); 1573 return FILL_ARRAY_TO_RIGHT[nargs] = filler; 1574 } 1575 private static MethodHandle buildFiller(int nargs) { 1576 if (nargs <= LEFT_ARGS) 1577 return Lazy.MH_arrayIdentity; // no args to fill; return the array unchanged 1578 // we need room for both mh and a in mh.invoke(a, arg*[nargs]) 1579 final int CHUNK = LEFT_ARGS; 1580 int rightLen = nargs % CHUNK; 1581 int midLen = nargs - rightLen; 1582 if (rightLen == 0) { 1583 midLen = nargs - (rightLen = CHUNK); 1584 if (FILL_ARRAY_TO_RIGHT[midLen] == null) { 1585 // build some precursors from left to right 1586 for (int j = LEFT_ARGS % CHUNK; j < midLen; j += CHUNK) 1587 if (j > LEFT_ARGS) fillToRight(j); 1588 } 1589 } 1590 if (midLen < LEFT_ARGS) rightLen = nargs - (midLen = LEFT_ARGS); 1591 assert(rightLen > 0); 1592 MethodHandle midFill = fillToRight(midLen); // recursive fill 1593 MethodHandle rightFill = Lazy.FILL_ARRAYS[rightLen].bindTo(midLen); // [midLen..nargs-1] 1594 assert(midFill.type().parameterCount() == 1 + midLen - LEFT_ARGS); 1595 assert(rightFill.type().parameterCount() == 1 + rightLen); 1596 1597 // Combine the two fills: 1598 // right(mid(a, x10..x19), x20..x23) 1599 // The final product will look like this: 1600 // right(mid(newArrayLeft(24, x0..x9), x10..x19), x20..x23) 1601 if (midLen == LEFT_ARGS) 1602 return rightFill; 1603 else 1604 return MethodHandles.collectArguments(rightFill, 0, midFill); 1605 } 1606 1607 // Type-polymorphic version of varargs maker. 1608 private static final ClassValue<MethodHandle[]> TYPED_COLLECTORS 1609 = new ClassValue<MethodHandle[]>() { 1610 @Override 1611 protected MethodHandle[] computeValue(Class<?> type) { 1612 return new MethodHandle[256]; 1613 } 1614 }; 1615 1616 static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM 1617 1618 /** Return a method handle that takes the indicated number of 1619 * typed arguments and returns an array of them. 1620 * The type argument is the array type. 1621 */ 1622 static MethodHandle varargsArray(Class<?> arrayType, int nargs) { 1623 Class<?> elemType = arrayType.getComponentType(); 1624 if (elemType == null) throw new IllegalArgumentException("not an array: "+arrayType); 1625 // FIXME: Need more special casing and caching here. 1626 if (nargs >= MAX_JVM_ARITY/2 - 1) { 1627 int slots = nargs; 1628 final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH 1629 if (slots <= MAX_ARRAY_SLOTS && elemType.isPrimitive()) 1630 slots *= Wrapper.forPrimitiveType(elemType).stackSlots(); 1631 if (slots > MAX_ARRAY_SLOTS) 1632 throw new IllegalArgumentException("too many arguments: "+arrayType.getSimpleName()+", length "+nargs); 1633 } 1634 if (elemType == Object.class) 1635 return varargsArray(nargs); 1636 // other cases: primitive arrays, subtypes of Object[] 1637 MethodHandle cache[] = TYPED_COLLECTORS.get(elemType); 1638 MethodHandle mh = nargs < cache.length ? cache[nargs] : null; 1639 if (mh != null) return mh; 1640 if (nargs == 0) { 1641 Object example = java.lang.reflect.Array.newInstance(arrayType.getComponentType(), 0); 1642 mh = MethodHandles.constant(arrayType, example); 1643 } else if (elemType.isPrimitive()) { 1644 MethodHandle builder = Lazy.MH_fillNewArray; 1645 MethodHandle producer = buildArrayProducer(arrayType); 1646 mh = buildVarargsArray(builder, producer, nargs); 1647 } else { 1648 Class<? extends Object[]> objArrayType = arrayType.asSubclass(Object[].class); 1649 Object[] example = Arrays.copyOf(NO_ARGS_ARRAY, 0, objArrayType); 1650 MethodHandle builder = Lazy.MH_fillNewTypedArray.bindTo(example); 1651 MethodHandle producer = Lazy.MH_arrayIdentity; // must be weakly typed 1652 mh = buildVarargsArray(builder, producer, nargs); 1653 } 1654 mh = mh.asType(MethodType.methodType(arrayType, Collections.<Class<?>>nCopies(nargs, elemType))); 1655 mh = makeIntrinsic(mh, Intrinsic.NEW_ARRAY); 1656 assert(assertCorrectArity(mh, nargs)); 1657 if (nargs < cache.length) 1658 cache[nargs] = mh; 1659 return mh; 1660 } 1661 1662 private static MethodHandle buildArrayProducer(Class<?> arrayType) { 1663 Class<?> elemType = arrayType.getComponentType(); 1664 assert(elemType.isPrimitive()); 1665 return Lazy.MH_copyAsPrimitiveArray.bindTo(Wrapper.forPrimitiveType(elemType)); 1666 } 1667 1668 /*non-public*/ static void assertSame(Object mh1, Object mh2) { 1669 if (mh1 != mh2) { 1670 String msg = String.format("mh1 != mh2: mh1 = %s (form: %s); mh2 = %s (form: %s)", 1671 mh1, ((MethodHandle)mh1).form, 1672 mh2, ((MethodHandle)mh2).form); 1673 throw newInternalError(msg); 1674 } 1675 } 1676 }