1 /* 2 * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.lang.invoke; 27 28 import jdk.internal.misc.Unsafe; 29 import jdk.internal.vm.annotation.ForceInline; 30 import jdk.internal.vm.annotation.Stable; 31 import sun.invoke.util.ValueConversions; 32 import sun.invoke.util.VerifyAccess; 33 import sun.invoke.util.VerifyType; 34 import sun.invoke.util.Wrapper; 35 36 import java.lang.ref.WeakReference; 37 import java.util.Arrays; 38 import java.util.Objects; 39 40 import static java.lang.invoke.LambdaForm.*; 41 import static java.lang.invoke.LambdaForm.Kind.*; 42 import static java.lang.invoke.MethodHandleNatives.Constants.*; 43 import static java.lang.invoke.MethodHandleStatics.UNSAFE; 44 import static java.lang.invoke.MethodHandleStatics.newInternalError; 45 import static java.lang.invoke.MethodTypeForm.*; 46 47 /** 48 * The flavor of method handle which implements a constant reference 49 * to a class member. 50 * @author jrose 51 */ 52 class DirectMethodHandle extends MethodHandle { 53 final MemberName member; 54 55 // Constructors and factory methods in this class *must* be package scoped or private. 56 private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member) { 57 super(mtype, form); 58 if (!member.isResolved()) throw new InternalError(); 59 60 if (member.getDeclaringClass().isInterface() && 61 member.getReferenceKind() == REF_invokeInterface && 62 member.isMethod() && !member.isAbstract()) { 63 // Check for corner case: invokeinterface of Object method 64 MemberName m = new MemberName(Object.class, member.getName(), member.getMethodType(), member.getReferenceKind()); 65 m = MemberName.getFactory().resolveOrNull(m.getReferenceKind(), m, null); 66 if (m != null && m.isPublic()) { 67 assert(member.getReferenceKind() == m.getReferenceKind()); // else this.form is wrong 68 member = m; 69 } 70 } 71 72 this.member = member; 73 } 74 75 // Factory methods: 76 static DirectMethodHandle make(byte refKind, Class<?> refc, MemberName member, Class<?> callerClass) { 77 MethodType mtype = member.getMethodOrFieldType(); 78 if (!member.isStatic()) { 79 if (!member.getDeclaringClass().isAssignableFrom(refc) || member.isConstructor()) 80 throw new InternalError(member.toString()); 81 mtype = mtype.insertParameterTypes(0, refc); 82 } 83 if (!member.isField()) { 84 switch (refKind) { 85 case REF_invokeSpecial: { 86 member = member.asSpecial(); 87 LambdaForm lform = preparedLambdaForm(member, callerClass); 88 Class<?> checkClass = refc; // Class to use for receiver type check 89 if (callerClass != null) { 90 checkClass = callerClass; // potentially strengthen to caller class 91 } 92 return new Special(mtype, lform, member, checkClass); 93 } 94 case REF_invokeInterface: { 95 LambdaForm lform = preparedLambdaForm(member, callerClass); 96 return new Interface(mtype, lform, member, refc); 97 } 98 default: { 99 LambdaForm lform = preparedLambdaForm(member, callerClass); 100 return new DirectMethodHandle(mtype, lform, member); 101 } 102 } 103 } else { 104 LambdaForm lform = preparedFieldLambdaForm(member); 105 if (member.isStatic()) { 106 long offset = MethodHandleNatives.staticFieldOffset(member); 107 Object base = MethodHandleNatives.staticFieldBase(member); 108 return new StaticAccessor(mtype, lform, member, base, offset); 109 } else { 110 long offset = MethodHandleNatives.objectFieldOffset(member); 111 assert(offset == (int)offset); 112 return new Accessor(mtype, lform, member, (int)offset); 113 } 114 } 115 } 116 static DirectMethodHandle make(Class<?> refc, MemberName member) { 117 byte refKind = member.getReferenceKind(); 118 if (refKind == REF_invokeSpecial) 119 refKind = REF_invokeVirtual; 120 return make(refKind, refc, member, null /* no callerClass context */); 121 } 122 static DirectMethodHandle make(MemberName member) { 123 if (member.isConstructor()) 124 return makeAllocator(member); 125 return make(member.getDeclaringClass(), member); 126 } 127 private static DirectMethodHandle makeAllocator(MemberName ctor) { 128 assert(ctor.isConstructor() && ctor.getName().equals("<init>")); 129 Class<?> instanceClass = ctor.getDeclaringClass(); 130 ctor = ctor.asConstructor(); 131 assert(ctor.isConstructor() && ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor; 132 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass); 133 LambdaForm lform = preparedLambdaForm(ctor); 134 MemberName init = ctor.asSpecial(); 135 assert(init.getMethodType().returnType() == void.class); 136 return new Constructor(mtype, lform, ctor, init, instanceClass); 137 } 138 139 @Override 140 BoundMethodHandle rebind() { 141 return BoundMethodHandle.makeReinvoker(this); 142 } 143 144 @Override 145 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 146 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses 147 return new DirectMethodHandle(mt, lf, member); 148 } 149 150 @Override 151 String internalProperties() { 152 return "\n& DMH.MN="+internalMemberName(); 153 } 154 155 //// Implementation methods. 156 @Override 157 @ForceInline 158 MemberName internalMemberName() { 159 return member; 160 } 161 162 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory(); 163 164 /** 165 * Create a LF which can invoke the given method. 166 * Cache and share this structure among all methods with 167 * the same basicType and refKind. 168 */ 169 private static LambdaForm preparedLambdaForm(MemberName m, Class<?> callerClass) { 170 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead 171 MethodType mtype = m.getInvocationType().basicType(); 172 assert(!m.isMethodHandleInvoke()) : m; 173 int which; 174 switch (m.getReferenceKind()) { 175 case REF_invokeVirtual: which = LF_INVVIRTUAL; break; 176 case REF_invokeStatic: which = LF_INVSTATIC; break; 177 case REF_invokeSpecial: which = LF_INVSPECIAL; break; 178 case REF_invokeInterface: which = LF_INVINTERFACE; break; 179 case REF_newInvokeSpecial: which = LF_NEWINVSPECIAL; break; 180 default: throw new InternalError(m.toString()); 181 } 182 if (which == LF_INVSTATIC && shouldBeInitialized(m)) { 183 // precompute the barrier-free version: 184 preparedLambdaForm(mtype, which); 185 which = LF_INVSTATIC_INIT; 186 } 187 if (which == LF_INVSPECIAL && callerClass != null && callerClass.isInterface()) { 188 which = LF_INVSPECIAL_IFC; 189 } 190 LambdaForm lform = preparedLambdaForm(mtype, which); 191 maybeCompile(lform, m); 192 assert(lform.methodType().dropParameterTypes(0, 1) 193 .equals(m.getInvocationType().basicType())) 194 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType()); 195 return lform; 196 } 197 198 private static LambdaForm preparedLambdaForm(MemberName m) { 199 return preparedLambdaForm(m, null); 200 } 201 202 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) { 203 LambdaForm lform = mtype.form().cachedLambdaForm(which); 204 if (lform != null) return lform; 205 lform = makePreparedLambdaForm(mtype, which); 206 return mtype.form().setCachedLambdaForm(which, lform); 207 } 208 209 static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) { 210 boolean needsInit = (which == LF_INVSTATIC_INIT); 211 boolean doesAlloc = (which == LF_NEWINVSPECIAL); 212 boolean needsReceiverCheck = (which == LF_INVINTERFACE || 213 which == LF_INVSPECIAL_IFC); 214 215 String linkerName; 216 LambdaForm.Kind kind; 217 switch (which) { 218 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break; 219 case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break; 220 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break; 221 case LF_INVSPECIAL_IFC:linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL_IFC; break; 222 case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break; 223 case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break; 224 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break; 225 default: throw new InternalError("which="+which); 226 } 227 228 MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class); 229 if (doesAlloc) 230 mtypeWithArg = mtypeWithArg 231 .insertParameterTypes(0, Object.class) // insert newly allocated obj 232 .changeReturnType(void.class); // <init> returns void 233 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic); 234 try { 235 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, NoSuchMethodException.class); 236 } catch (ReflectiveOperationException ex) { 237 throw newInternalError(ex); 238 } 239 final int DMH_THIS = 0; 240 final int ARG_BASE = 1; 241 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount(); 242 int nameCursor = ARG_LIMIT; 243 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1); 244 final int GET_MEMBER = nameCursor++; 245 final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1); 246 final int LINKER_CALL = nameCursor++; 247 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType()); 248 assert(names.length == nameCursor); 249 if (doesAlloc) { 250 // names = { argx,y,z,... new C, init method } 251 names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]); 252 names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]); 253 } else if (needsInit) { 254 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]); 255 } else { 256 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]); 257 } 258 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]); 259 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class); 260 if (needsReceiverCheck) { 261 names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]); 262 outArgs[0] = names[CHECK_RECEIVER]; 263 } 264 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args! 265 int result = LAST_RESULT; 266 if (doesAlloc) { 267 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one 268 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2); 269 outArgs[0] = names[NEW_OBJ]; 270 result = NEW_OBJ; 271 } 272 names[LINKER_CALL] = new Name(linker, outArgs); 273 LambdaForm lform = new LambdaForm(ARG_LIMIT, names, result, kind); 274 275 // This is a tricky bit of code. Don't send it through the LF interpreter. 276 lform.compileToBytecode(); 277 return lform; 278 } 279 280 /* assert */ static Object findDirectMethodHandle(Name name) { 281 if (name.function.equals(getFunction(NF_internalMemberName)) || 282 name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) || 283 name.function.equals(getFunction(NF_constructorMethod))) { 284 assert(name.arguments.length == 1); 285 return name.arguments[0]; 286 } 287 return null; 288 } 289 290 private static void maybeCompile(LambdaForm lform, MemberName m) { 291 if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class)) 292 // Help along bootstrapping... 293 lform.compileToBytecode(); 294 } 295 296 /** Static wrapper for DirectMethodHandle.internalMemberName. */ 297 @ForceInline 298 /*non-public*/ static Object internalMemberName(Object mh) { 299 return ((DirectMethodHandle)mh).member; 300 } 301 302 /** Static wrapper for DirectMethodHandle.internalMemberName. 303 * This one also forces initialization. 304 */ 305 /*non-public*/ static Object internalMemberNameEnsureInit(Object mh) { 306 DirectMethodHandle dmh = (DirectMethodHandle)mh; 307 dmh.ensureInitialized(); 308 return dmh.member; 309 } 310 311 /*non-public*/ static 312 boolean shouldBeInitialized(MemberName member) { 313 switch (member.getReferenceKind()) { 314 case REF_invokeStatic: 315 case REF_getStatic: 316 case REF_putStatic: 317 case REF_newInvokeSpecial: 318 break; 319 default: 320 // No need to initialize the class on this kind of member. 321 return false; 322 } 323 Class<?> cls = member.getDeclaringClass(); 324 if (cls == ValueConversions.class || 325 cls == MethodHandleImpl.class || 326 cls == Invokers.class) { 327 // These guys have lots of <clinit> DMH creation but we know 328 // the MHs will not be used until the system is booted. 329 return false; 330 } 331 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) || 332 VerifyAccess.isSamePackage(ValueConversions.class, cls)) { 333 // It is a system class. It is probably in the process of 334 // being initialized, but we will help it along just to be safe. 335 if (UNSAFE.shouldBeInitialized(cls)) { 336 UNSAFE.ensureClassInitialized(cls); 337 } 338 return false; 339 } 340 return UNSAFE.shouldBeInitialized(cls); 341 } 342 343 private static class EnsureInitialized extends ClassValue<WeakReference<Thread>> { 344 @Override 345 protected WeakReference<Thread> computeValue(Class<?> type) { 346 UNSAFE.ensureClassInitialized(type); 347 if (UNSAFE.shouldBeInitialized(type)) 348 // If the previous call didn't block, this can happen. 349 // We are executing inside <clinit>. 350 return new WeakReference<>(Thread.currentThread()); 351 return null; 352 } 353 static final EnsureInitialized INSTANCE = new EnsureInitialized(); 354 } 355 356 private void ensureInitialized() { 357 if (checkInitialized(member)) { 358 // The coast is clear. Delete the <clinit> barrier. 359 if (member.isField()) 360 updateForm(preparedFieldLambdaForm(member)); 361 else 362 updateForm(preparedLambdaForm(member)); 363 } 364 } 365 private static boolean checkInitialized(MemberName member) { 366 Class<?> defc = member.getDeclaringClass(); 367 WeakReference<Thread> ref = EnsureInitialized.INSTANCE.get(defc); 368 if (ref == null) { 369 return true; // the final state 370 } 371 Thread clinitThread = ref.get(); 372 // Somebody may still be running defc.<clinit>. 373 if (clinitThread == Thread.currentThread()) { 374 // If anybody is running defc.<clinit>, it is this thread. 375 if (UNSAFE.shouldBeInitialized(defc)) 376 // Yes, we are running it; keep the barrier for now. 377 return false; 378 } else { 379 // We are in a random thread. Block. 380 UNSAFE.ensureClassInitialized(defc); 381 } 382 assert(!UNSAFE.shouldBeInitialized(defc)); 383 // put it into the final state 384 EnsureInitialized.INSTANCE.remove(defc); 385 return true; 386 } 387 388 /*non-public*/ static void ensureInitialized(Object mh) { 389 ((DirectMethodHandle)mh).ensureInitialized(); 390 } 391 392 /** This subclass represents invokespecial instructions. */ 393 static class Special extends DirectMethodHandle { 394 private final Class<?> caller; 395 private Special(MethodType mtype, LambdaForm form, MemberName member, Class<?> caller) { 396 super(mtype, form, member); 397 this.caller = caller; 398 } 399 @Override 400 boolean isInvokeSpecial() { 401 return true; 402 } 403 @Override 404 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 405 return new Special(mt, lf, member, caller); 406 } 407 Object checkReceiver(Object recv) { 408 if (!caller.isInstance(recv)) { 409 String msg = String.format("Receiver class %s is not a subclass of caller class %s", 410 recv.getClass().getName(), caller.getName()); 411 throw new IncompatibleClassChangeError(msg); 412 } 413 return recv; 414 } 415 } 416 417 /** This subclass represents invokeinterface instructions. */ 418 static class Interface extends DirectMethodHandle { 419 private final Class<?> refc; 420 private Interface(MethodType mtype, LambdaForm form, MemberName member, Class<?> refc) { 421 super(mtype, form, member); 422 assert refc.isInterface() : refc; 423 this.refc = refc; 424 } 425 @Override 426 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 427 return new Interface(mt, lf, member, refc); 428 } 429 @Override 430 Object checkReceiver(Object recv) { 431 if (!refc.isInstance(recv)) { 432 String msg = String.format("Receiver class %s does not implement the requested interface %s", 433 recv.getClass().getName(), refc.getName()); 434 throw new IncompatibleClassChangeError(msg); 435 } 436 return recv; 437 } 438 } 439 440 /** Used for interface receiver type checks, by Interface and Special modes. */ 441 Object checkReceiver(Object recv) { 442 throw new InternalError("Should only be invoked on a subclass"); 443 } 444 445 446 /** This subclass handles constructor references. */ 447 static class Constructor extends DirectMethodHandle { 448 final MemberName initMethod; 449 final Class<?> instanceClass; 450 451 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor, 452 MemberName initMethod, Class<?> instanceClass) { 453 super(mtype, form, constructor); 454 this.initMethod = initMethod; 455 this.instanceClass = instanceClass; 456 assert(initMethod.isResolved()); 457 } 458 @Override 459 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 460 return new Constructor(mt, lf, member, initMethod, instanceClass); 461 } 462 } 463 464 /*non-public*/ static Object constructorMethod(Object mh) { 465 Constructor dmh = (Constructor)mh; 466 return dmh.initMethod; 467 } 468 469 /*non-public*/ static Object allocateInstance(Object mh) throws InstantiationException { 470 Constructor dmh = (Constructor)mh; 471 return UNSAFE.allocateInstance(dmh.instanceClass); 472 } 473 474 /** This subclass handles non-static field references. */ 475 static class Accessor extends DirectMethodHandle { 476 final Class<?> fieldType; 477 final int fieldOffset; 478 private Accessor(MethodType mtype, LambdaForm form, MemberName member, 479 int fieldOffset) { 480 super(mtype, form, member); 481 this.fieldType = member.getFieldType(); 482 this.fieldOffset = fieldOffset; 483 } 484 485 @Override Object checkCast(Object obj) { 486 return fieldType.cast(obj); 487 } 488 @Override 489 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 490 return new Accessor(mt, lf, member, fieldOffset); 491 } 492 } 493 494 @ForceInline 495 /*non-public*/ static long fieldOffset(Object accessorObj) { 496 // Note: We return a long because that is what Unsafe.getObject likes. 497 // We store a plain int because it is more compact. 498 return ((Accessor)accessorObj).fieldOffset; 499 } 500 501 @ForceInline 502 /*non-public*/ static Object checkBase(Object obj) { 503 // Note that the object's class has already been verified, 504 // since the parameter type of the Accessor method handle 505 // is either member.getDeclaringClass or a subclass. 506 // This was verified in DirectMethodHandle.make. 507 // Therefore, the only remaining check is for null. 508 // Since this check is *not* guaranteed by Unsafe.getInt 509 // and its siblings, we need to make an explicit one here. 510 return Objects.requireNonNull(obj); 511 } 512 513 /** This subclass handles static field references. */ 514 static class StaticAccessor extends DirectMethodHandle { 515 private final Class<?> fieldType; 516 private final Object staticBase; 517 private final long staticOffset; 518 519 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member, 520 Object staticBase, long staticOffset) { 521 super(mtype, form, member); 522 this.fieldType = member.getFieldType(); 523 this.staticBase = staticBase; 524 this.staticOffset = staticOffset; 525 } 526 527 @Override Object checkCast(Object obj) { 528 return fieldType.cast(obj); 529 } 530 @Override 531 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 532 return new StaticAccessor(mt, lf, member, staticBase, staticOffset); 533 } 534 } 535 536 @ForceInline 537 /*non-public*/ static Object nullCheck(Object obj) { 538 return Objects.requireNonNull(obj); 539 } 540 541 @ForceInline 542 /*non-public*/ static Object staticBase(Object accessorObj) { 543 return ((StaticAccessor)accessorObj).staticBase; 544 } 545 546 @ForceInline 547 /*non-public*/ static long staticOffset(Object accessorObj) { 548 return ((StaticAccessor)accessorObj).staticOffset; 549 } 550 551 @ForceInline 552 /*non-public*/ static Object checkCast(Object mh, Object obj) { 553 return ((DirectMethodHandle) mh).checkCast(obj); 554 } 555 556 Object checkCast(Object obj) { 557 return member.getReturnType().cast(obj); 558 } 559 560 // Caching machinery for field accessors: 561 static final byte 562 AF_GETFIELD = 0, 563 AF_PUTFIELD = 1, 564 AF_GETSTATIC = 2, 565 AF_PUTSTATIC = 3, 566 AF_GETSTATIC_INIT = 4, 567 AF_PUTSTATIC_INIT = 5, 568 AF_LIMIT = 6; 569 // Enumerate the different field kinds using Wrapper, 570 // with an extra case added for checked references. 571 static final int 572 FT_LAST_WRAPPER = Wrapper.COUNT-1, 573 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(), 574 FT_CHECKED_REF = FT_LAST_WRAPPER+1, 575 FT_LIMIT = FT_LAST_WRAPPER+2; 576 private static int afIndex(byte formOp, boolean isVolatile, int ftypeKind) { 577 return ((formOp * FT_LIMIT * 2) 578 + (isVolatile ? FT_LIMIT : 0) 579 + ftypeKind); 580 } 581 @Stable 582 private static final LambdaForm[] ACCESSOR_FORMS 583 = new LambdaForm[afIndex(AF_LIMIT, false, 0)]; 584 static int ftypeKind(Class<?> ftype) { 585 if (ftype.isPrimitive()) 586 return Wrapper.forPrimitiveType(ftype).ordinal(); 587 else if (VerifyType.isNullReferenceConversion(Object.class, ftype)) 588 return FT_UNCHECKED_REF; 589 else 590 return FT_CHECKED_REF; 591 } 592 593 /** 594 * Create a LF which can access the given field. 595 * Cache and share this structure among all fields with 596 * the same basicType and refKind. 597 */ 598 private static LambdaForm preparedFieldLambdaForm(MemberName m) { 599 Class<?> ftype = m.getFieldType(); 600 boolean isVolatile = m.isVolatile(); 601 byte formOp; 602 switch (m.getReferenceKind()) { 603 case REF_getField: formOp = AF_GETFIELD; break; 604 case REF_putField: formOp = AF_PUTFIELD; break; 605 case REF_getStatic: formOp = AF_GETSTATIC; break; 606 case REF_putStatic: formOp = AF_PUTSTATIC; break; 607 default: throw new InternalError(m.toString()); 608 } 609 if (shouldBeInitialized(m)) { 610 // precompute the barrier-free version: 611 preparedFieldLambdaForm(formOp, isVolatile, ftype); 612 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) == 613 (AF_PUTSTATIC_INIT - AF_PUTSTATIC)); 614 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC); 615 } 616 LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, ftype); 617 maybeCompile(lform, m); 618 assert(lform.methodType().dropParameterTypes(0, 1) 619 .equals(m.getInvocationType().basicType())) 620 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType()); 621 return lform; 622 } 623 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, Class<?> ftype) { 624 int ftypeKind = ftypeKind(ftype); 625 int afIndex = afIndex(formOp, isVolatile, ftypeKind); 626 LambdaForm lform = ACCESSOR_FORMS[afIndex]; 627 if (lform != null) return lform; 628 lform = makePreparedFieldLambdaForm(formOp, isVolatile, ftypeKind); 629 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS 630 return lform; 631 } 632 633 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values(); 634 635 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, Wrapper wrapper) { 636 if (isGetter) { 637 if (isVolatile) { 638 switch (wrapper) { 639 case BOOLEAN: return GET_BOOLEAN_VOLATILE; 640 case BYTE: return GET_BYTE_VOLATILE; 641 case SHORT: return GET_SHORT_VOLATILE; 642 case CHAR: return GET_CHAR_VOLATILE; 643 case INT: return GET_INT_VOLATILE; 644 case LONG: return GET_LONG_VOLATILE; 645 case FLOAT: return GET_FLOAT_VOLATILE; 646 case DOUBLE: return GET_DOUBLE_VOLATILE; 647 case OBJECT: return GET_OBJECT_VOLATILE; 648 } 649 } else { 650 switch (wrapper) { 651 case BOOLEAN: return GET_BOOLEAN; 652 case BYTE: return GET_BYTE; 653 case SHORT: return GET_SHORT; 654 case CHAR: return GET_CHAR; 655 case INT: return GET_INT; 656 case LONG: return GET_LONG; 657 case FLOAT: return GET_FLOAT; 658 case DOUBLE: return GET_DOUBLE; 659 case OBJECT: return GET_OBJECT; 660 } 661 } 662 } else { 663 if (isVolatile) { 664 switch (wrapper) { 665 case BOOLEAN: return PUT_BOOLEAN_VOLATILE; 666 case BYTE: return PUT_BYTE_VOLATILE; 667 case SHORT: return PUT_SHORT_VOLATILE; 668 case CHAR: return PUT_CHAR_VOLATILE; 669 case INT: return PUT_INT_VOLATILE; 670 case LONG: return PUT_LONG_VOLATILE; 671 case FLOAT: return PUT_FLOAT_VOLATILE; 672 case DOUBLE: return PUT_DOUBLE_VOLATILE; 673 case OBJECT: return PUT_OBJECT_VOLATILE; 674 } 675 } else { 676 switch (wrapper) { 677 case BOOLEAN: return PUT_BOOLEAN; 678 case BYTE: return PUT_BYTE; 679 case SHORT: return PUT_SHORT; 680 case CHAR: return PUT_CHAR; 681 case INT: return PUT_INT; 682 case LONG: return PUT_LONG; 683 case FLOAT: return PUT_FLOAT; 684 case DOUBLE: return PUT_DOUBLE; 685 case OBJECT: return PUT_OBJECT; 686 } 687 } 688 } 689 throw new AssertionError("Invalid arguments"); 690 } 691 692 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftypeKind) { 693 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1); 694 boolean isStatic = (formOp >= AF_GETSTATIC); 695 boolean needsInit = (formOp >= AF_GETSTATIC_INIT); 696 boolean needsCast = (ftypeKind == FT_CHECKED_REF); 697 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]); 698 Class<?> ft = fw.primitiveType(); 699 assert(ftypeKind(needsCast ? String.class : ft) == ftypeKind); 700 701 // getObject, putIntVolatile, etc. 702 Kind kind = getFieldKind(isGetter, isVolatile, fw); 703 704 MethodType linkerType; 705 if (isGetter) 706 linkerType = MethodType.methodType(ft, Object.class, long.class); 707 else 708 linkerType = MethodType.methodType(void.class, Object.class, long.class, ft); 709 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual); 710 try { 711 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, NoSuchMethodException.class); 712 } catch (ReflectiveOperationException ex) { 713 throw newInternalError(ex); 714 } 715 716 // What is the external type of the lambda form? 717 MethodType mtype; 718 if (isGetter) 719 mtype = MethodType.methodType(ft); 720 else 721 mtype = MethodType.methodType(void.class, ft); 722 mtype = mtype.basicType(); // erase short to int, etc. 723 if (!isStatic) 724 mtype = mtype.insertParameterTypes(0, Object.class); 725 final int DMH_THIS = 0; 726 final int ARG_BASE = 1; 727 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount(); 728 // if this is for non-static access, the base pointer is stored at this index: 729 final int OBJ_BASE = isStatic ? -1 : ARG_BASE; 730 // if this is for write access, the value to be written is stored at this index: 731 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1; 732 int nameCursor = ARG_LIMIT; 733 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any 734 final int F_OFFSET = nameCursor++; // Either static offset or field offset. 735 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1); 736 final int U_HOLDER = nameCursor++; // UNSAFE holder 737 final int INIT_BAR = (needsInit ? nameCursor++ : -1); 738 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1); 739 final int LINKER_CALL = nameCursor++; 740 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1); 741 final int RESULT = nameCursor-1; // either the call or the cast 742 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType()); 743 if (needsInit) 744 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]); 745 if (needsCast && !isGetter) 746 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]); 747 Object[] outArgs = new Object[1 + linkerType.parameterCount()]; 748 assert(outArgs.length == (isGetter ? 3 : 4)); 749 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE)); 750 if (isStatic) { 751 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]); 752 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]); 753 } else { 754 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]); 755 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]); 756 } 757 if (!isGetter) { 758 outArgs[3] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]); 759 } 760 for (Object a : outArgs) assert(a != null); 761 names[LINKER_CALL] = new Name(linker, outArgs); 762 if (needsCast && isGetter) 763 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]); 764 for (Name n : names) assert(n != null); 765 766 LambdaForm form; 767 if (needsCast || needsInit) { 768 // can't use the pre-generated form when casting and/or initializing 769 form = new LambdaForm(ARG_LIMIT, names, RESULT); 770 } else { 771 form = new LambdaForm(ARG_LIMIT, names, RESULT, kind); 772 } 773 774 if (LambdaForm.debugNames()) { 775 // add some detail to the lambdaForm debugname, 776 // significant only for debugging 777 StringBuilder nameBuilder = new StringBuilder(kind.methodName); 778 if (isStatic) { 779 nameBuilder.append("Static"); 780 } else { 781 nameBuilder.append("Field"); 782 } 783 if (needsCast) { 784 nameBuilder.append("Cast"); 785 } 786 if (needsInit) { 787 nameBuilder.append("Init"); 788 } 789 LambdaForm.associateWithDebugName(form, nameBuilder.toString()); 790 } 791 return form; 792 } 793 794 /** 795 * Pre-initialized NamedFunctions for bootstrapping purposes. 796 */ 797 static final byte NF_internalMemberName = 0, 798 NF_internalMemberNameEnsureInit = 1, 799 NF_ensureInitialized = 2, 800 NF_fieldOffset = 3, 801 NF_checkBase = 4, 802 NF_staticBase = 5, 803 NF_staticOffset = 6, 804 NF_checkCast = 7, 805 NF_allocateInstance = 8, 806 NF_constructorMethod = 9, 807 NF_UNSAFE = 10, 808 NF_checkReceiver = 11, 809 NF_LIMIT = 12; 810 811 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT]; 812 813 private static NamedFunction getFunction(byte func) { 814 NamedFunction nf = NFS[func]; 815 if (nf != null) { 816 return nf; 817 } 818 // Each nf must be statically invocable or we get tied up in our bootstraps. 819 nf = NFS[func] = createFunction(func); 820 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf)); 821 return nf; 822 } 823 824 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class); 825 826 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class); 827 828 private static NamedFunction createFunction(byte func) { 829 try { 830 switch (func) { 831 case NF_internalMemberName: 832 return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE); 833 case NF_internalMemberNameEnsureInit: 834 return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE); 835 case NF_ensureInitialized: 836 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class)); 837 case NF_fieldOffset: 838 return getNamedFunction("fieldOffset", LONG_OBJ_TYPE); 839 case NF_checkBase: 840 return getNamedFunction("checkBase", OBJ_OBJ_TYPE); 841 case NF_staticBase: 842 return getNamedFunction("staticBase", OBJ_OBJ_TYPE); 843 case NF_staticOffset: 844 return getNamedFunction("staticOffset", LONG_OBJ_TYPE); 845 case NF_checkCast: 846 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class)); 847 case NF_allocateInstance: 848 return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE); 849 case NF_constructorMethod: 850 return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE); 851 case NF_UNSAFE: 852 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getField); 853 return new NamedFunction( 854 MemberName.getFactory() 855 .resolveOrFail(REF_getField, member, DirectMethodHandle.class, NoSuchMethodException.class)); 856 case NF_checkReceiver: 857 member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual); 858 return new NamedFunction( 859 MemberName.getFactory() 860 .resolveOrFail(REF_invokeVirtual, member, DirectMethodHandle.class, NoSuchMethodException.class)); 861 default: 862 throw newInternalError("Unknown function: " + func); 863 } 864 } catch (ReflectiveOperationException ex) { 865 throw newInternalError(ex); 866 } 867 } 868 869 private static NamedFunction getNamedFunction(String name, MethodType type) 870 throws ReflectiveOperationException 871 { 872 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic); 873 return new NamedFunction( 874 MemberName.getFactory() 875 .resolveOrFail(REF_invokeStatic, member, DirectMethodHandle.class, NoSuchMethodException.class)); 876 } 877 878 static { 879 // The Holder class will contain pre-generated DirectMethodHandles resolved 880 // speculatively using MemberName.getFactory().resolveOrNull. However, that 881 // doesn't initialize the class, which subtly breaks inlining etc. By forcing 882 // initialization of the Holder class we avoid these issues. 883 UNSAFE.ensureClassInitialized(Holder.class); 884 } 885 886 /* Placeholder class for DirectMethodHandles generated ahead of time */ 887 final class Holder {} 888 }