1 /* 2 * Copyright (c) 2008, 2020, 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.util.Arrays; 37 import java.util.Objects; 38 import java.util.function.Function; 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 final boolean crackable; 55 56 // Constructors and factory methods in this class *must* be package scoped or private. 57 private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member, boolean crackable) { 58 super(mtype, form); 59 if (!member.isResolved()) throw new InternalError(); 60 61 if (member.getDeclaringClass().isInterface() && 62 member.getReferenceKind() == REF_invokeInterface && 63 member.isMethod() && !member.isAbstract()) { 64 // Check for corner case: invokeinterface of Object method 65 MemberName m = new MemberName(Object.class, member.getName(), member.getMethodType(), member.getReferenceKind()); 66 m = MemberName.getFactory().resolveOrNull(m.getReferenceKind(), m, null, LM_TRUSTED); 67 if (m != null && m.isPublic()) { 68 assert(member.getReferenceKind() == m.getReferenceKind()); // else this.form is wrong 69 member = m; 70 } 71 } 72 73 this.member = member; 74 this.crackable = crackable; 75 } 76 77 // Factory methods: 78 static DirectMethodHandle make(byte refKind, Class<?> refc, MemberName member, Class<?> callerClass) { 79 MethodType mtype = member.getMethodOrFieldType(); 80 if (!member.isStatic()) { 81 if (!member.getDeclaringClass().isAssignableFrom(refc) || member.isObjectConstructor()) 82 throw new InternalError(member.toString()); 83 Class<?> receiverType = refc.isPrimitiveClass() ? refc.asValueType() : refc; 84 mtype = mtype.insertParameterTypes(0, receiverType); 85 } 86 if (!member.isField()) { 87 // refKind reflects the original type of lookup via findSpecial or 88 // findVirtual etc. 89 return switch (refKind) { 90 case REF_invokeSpecial -> { 91 member = member.asSpecial(); 92 // if caller is an interface we need to adapt to get the 93 // receiver check inserted 94 if (callerClass == null) { 95 throw new InternalError("callerClass must not be null for REF_invokeSpecial"); 96 } 97 LambdaForm lform = preparedLambdaForm(member, callerClass.isInterface()); 98 yield new Special(mtype, lform, member, true, callerClass); 99 } 100 case REF_invokeInterface -> { 101 // for interfaces we always need the receiver typecheck, 102 // so we always pass 'true' to ensure we adapt if needed 103 // to include the REF_invokeSpecial case 104 LambdaForm lform = preparedLambdaForm(member, true); 105 yield new Interface(mtype, lform, member, true, refc); 106 } 107 default -> { 108 LambdaForm lform = preparedLambdaForm(member); 109 yield new DirectMethodHandle(mtype, lform, member, true); 110 } 111 }; 112 } else { 113 LambdaForm lform = preparedFieldLambdaForm(member); 114 if (member.isStatic()) { 115 long offset = MethodHandleNatives.staticFieldOffset(member); 116 Object base = MethodHandleNatives.staticFieldBase(member); 117 return new StaticAccessor(mtype, lform, member, true, base, offset); 118 } else { 119 long offset = MethodHandleNatives.objectFieldOffset(member); 120 assert(offset == (int)offset); 121 return new Accessor(mtype, lform, member, true, (int)offset); 122 } 123 } 124 } 125 static DirectMethodHandle make(Class<?> refc, MemberName member) { 126 byte refKind = member.getReferenceKind(); 127 if (refKind == REF_invokeSpecial) 128 refKind = REF_invokeVirtual; 129 return make(refKind, refc, member, null /* no callerClass context */); 130 } 131 static DirectMethodHandle make(MemberName member) { 132 if (member.isObjectConstructor() && member.getReturnType() == void.class) 133 return makeAllocator(member); 134 return make(member.getDeclaringClass(), member); 135 } 136 private static DirectMethodHandle makeAllocator(MemberName ctor) { 137 assert(ctor.isObjectConstructor() && !ctor.getDeclaringClass().isValue()) : ctor; 138 139 Class<?> instanceClass = ctor.getDeclaringClass(); 140 ctor = ctor.asObjectConstructor(); 141 assert(ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor; 142 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass); 143 LambdaForm lform = preparedLambdaForm(ctor); 144 MemberName init = ctor.asSpecial(); 145 assert(init.getMethodType().returnType() == void.class); 146 return new Constructor(mtype, lform, ctor, true, init, instanceClass); 147 } 148 149 @Override 150 BoundMethodHandle rebind() { 151 return BoundMethodHandle.makeReinvoker(this); 152 } 153 154 @Override 155 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 156 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses 157 return new DirectMethodHandle(mt, lf, member, crackable); 158 } 159 160 @Override 161 MethodHandle viewAsType(MethodType newType, boolean strict) { 162 // No actual conversions, just a new view of the same method. 163 // However, we must not expose a DMH that is crackable into a 164 // MethodHandleInfo, so we return a cloned, uncrackable DMH 165 assert(viewAsTypeChecks(newType, strict)); 166 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses 167 return new DirectMethodHandle(newType, form, member, false); 168 } 169 170 @Override 171 boolean isCrackable() { 172 return crackable; 173 } 174 175 @Override 176 String internalProperties() { 177 return "\n& DMH.MN="+internalMemberName(); 178 } 179 180 //// Implementation methods. 181 @Override 182 @ForceInline 183 MemberName internalMemberName() { 184 return member; 185 } 186 187 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory(); 188 189 /** 190 * Create a LF which can invoke the given method. 191 * Cache and share this structure among all methods with 192 * the same basicType and refKind. 193 */ 194 private static LambdaForm preparedLambdaForm(MemberName m, boolean adaptToSpecialIfc) { 195 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead 196 MethodType mtype = m.getInvocationType().basicType(); 197 assert(!m.isMethodHandleInvoke()) : m; 198 // MemberName.getReferenceKind represents the JVM optimized form of the call 199 // as distinct from the "kind" passed to DMH.make which represents the original 200 // bytecode-equivalent request. Specifically private/final methods that use a direct 201 // call have getReferenceKind adapted to REF_invokeSpecial, even though the actual 202 // invocation mode may be invokevirtual or invokeinterface. 203 int which = switch (m.getReferenceKind()) { 204 case REF_invokeVirtual -> LF_INVVIRTUAL; 205 case REF_invokeStatic -> LF_INVSTATIC; 206 case REF_invokeSpecial -> LF_INVSPECIAL; 207 case REF_invokeInterface -> LF_INVINTERFACE; 208 case REF_newInvokeSpecial -> LF_NEWINVSPECIAL; 209 default -> throw new InternalError(m.toString()); 210 }; 211 if (which == LF_INVSTATIC && shouldBeInitialized(m)) { 212 // precompute the barrier-free version: 213 preparedLambdaForm(mtype, which); 214 which = LF_INVSTATIC_INIT; 215 } 216 if (which == LF_INVSPECIAL && adaptToSpecialIfc) { 217 which = LF_INVSPECIAL_IFC; 218 } 219 LambdaForm lform = preparedLambdaForm(mtype, which); 220 maybeCompile(lform, m); 221 assert(lform.methodType().dropParameterTypes(0, 1) 222 .equals(m.getInvocationType().basicType())) 223 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType()); 224 return lform; 225 } 226 227 private static LambdaForm preparedLambdaForm(MemberName m) { 228 return preparedLambdaForm(m, false); 229 } 230 231 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) { 232 LambdaForm lform = mtype.form().cachedLambdaForm(which); 233 if (lform != null) return lform; 234 lform = makePreparedLambdaForm(mtype, which); 235 return mtype.form().setCachedLambdaForm(which, lform); 236 } 237 238 static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) { 239 boolean needsInit = (which == LF_INVSTATIC_INIT); 240 boolean doesAlloc = (which == LF_NEWINVSPECIAL); 241 boolean needsReceiverCheck = (which == LF_INVINTERFACE || 242 which == LF_INVSPECIAL_IFC); 243 244 String linkerName; 245 LambdaForm.Kind kind; 246 switch (which) { 247 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break; 248 case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break; 249 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break; 250 case LF_INVSPECIAL_IFC:linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL_IFC; break; 251 case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break; 252 case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break; 253 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break; 254 default: throw new InternalError("which="+which); 255 } 256 257 MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class); 258 if (doesAlloc) 259 mtypeWithArg = mtypeWithArg 260 .insertParameterTypes(0, Object.class) // insert newly allocated obj 261 .changeReturnType(void.class); // <init> returns void 262 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic); 263 try { 264 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, LM_TRUSTED, 265 NoSuchMethodException.class); 266 } catch (ReflectiveOperationException ex) { 267 throw newInternalError(ex); 268 } 269 final int DMH_THIS = 0; 270 final int ARG_BASE = 1; 271 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount(); 272 int nameCursor = ARG_LIMIT; 273 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1); 274 final int GET_MEMBER = nameCursor++; 275 final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1); 276 final int LINKER_CALL = nameCursor++; 277 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType()); 278 assert(names.length == nameCursor); 279 if (doesAlloc) { 280 // names = { argx,y,z,... new C, init method } 281 names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]); 282 names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]); 283 } else if (needsInit) { 284 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]); 285 } else { 286 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]); 287 } 288 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]); 289 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class); 290 if (needsReceiverCheck) { 291 names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]); 292 outArgs[0] = names[CHECK_RECEIVER]; 293 } 294 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args! 295 int result = LAST_RESULT; 296 if (doesAlloc) { 297 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one 298 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2); 299 outArgs[0] = names[NEW_OBJ]; 300 result = NEW_OBJ; 301 } 302 names[LINKER_CALL] = new Name(linker, outArgs); 303 LambdaForm lform = new LambdaForm(ARG_LIMIT, names, result, kind); 304 305 // This is a tricky bit of code. Don't send it through the LF interpreter. 306 lform.compileToBytecode(); 307 return lform; 308 } 309 310 /* assert */ static Object findDirectMethodHandle(Name name) { 311 if (name.function.equals(getFunction(NF_internalMemberName)) || 312 name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) || 313 name.function.equals(getFunction(NF_constructorMethod))) { 314 assert(name.arguments.length == 1); 315 return name.arguments[0]; 316 } 317 return null; 318 } 319 320 private static void maybeCompile(LambdaForm lform, MemberName m) { 321 if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class)) 322 // Help along bootstrapping... 323 lform.compileToBytecode(); 324 } 325 326 /** Static wrapper for DirectMethodHandle.internalMemberName. */ 327 @ForceInline 328 /*non-public*/ 329 static Object internalMemberName(Object mh) { 330 return ((DirectMethodHandle)mh).member; 331 } 332 333 /** Static wrapper for DirectMethodHandle.internalMemberName. 334 * This one also forces initialization. 335 */ 336 /*non-public*/ 337 static Object internalMemberNameEnsureInit(Object mh) { 338 DirectMethodHandle dmh = (DirectMethodHandle)mh; 339 dmh.ensureInitialized(); 340 return dmh.member; 341 } 342 343 /*non-public*/ 344 static boolean shouldBeInitialized(MemberName member) { 345 switch (member.getReferenceKind()) { 346 case REF_invokeStatic: 347 case REF_getStatic: 348 case REF_putStatic: 349 case REF_newInvokeSpecial: 350 break; 351 default: 352 // No need to initialize the class on this kind of member. 353 return false; 354 } 355 Class<?> cls = member.getDeclaringClass(); 356 if (cls == ValueConversions.class || 357 cls == MethodHandleImpl.class || 358 cls == Invokers.class) { 359 // These guys have lots of <clinit> DMH creation but we know 360 // the MHs will not be used until the system is booted. 361 return false; 362 } 363 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) || 364 VerifyAccess.isSamePackage(ValueConversions.class, cls)) { 365 // It is a system class. It is probably in the process of 366 // being initialized, but we will help it along just to be safe. 367 UNSAFE.ensureClassInitialized(cls); 368 return false; 369 } 370 return UNSAFE.shouldBeInitialized(cls); 371 } 372 373 private void ensureInitialized() { 374 if (checkInitialized(member)) { 375 // The coast is clear. Delete the <clinit> barrier. 376 updateForm(new Function<>() { 377 public LambdaForm apply(LambdaForm oldForm) { 378 return (member.isField() ? preparedFieldLambdaForm(member) 379 : preparedLambdaForm(member)); 380 } 381 }); 382 } 383 } 384 private static boolean checkInitialized(MemberName member) { 385 Class<?> defc = member.getDeclaringClass(); 386 UNSAFE.ensureClassInitialized(defc); 387 // Once we get here either defc was fully initialized by another thread, or 388 // defc was already being initialized by the current thread. In the latter case 389 // the barrier must remain. We can detect this simply by checking if initialization 390 // is still needed. 391 return !UNSAFE.shouldBeInitialized(defc); 392 } 393 394 /*non-public*/ 395 static void ensureInitialized(Object mh) { 396 ((DirectMethodHandle)mh).ensureInitialized(); 397 } 398 399 /** This subclass represents invokespecial instructions. */ 400 static class Special extends DirectMethodHandle { 401 private final Class<?> caller; 402 private Special(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> caller) { 403 super(mtype, form, member, crackable); 404 this.caller = caller; 405 } 406 @Override 407 boolean isInvokeSpecial() { 408 return true; 409 } 410 @Override 411 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 412 return new Special(mt, lf, member, crackable, caller); 413 } 414 @Override 415 MethodHandle viewAsType(MethodType newType, boolean strict) { 416 assert(viewAsTypeChecks(newType, strict)); 417 return new Special(newType, form, member, false, caller); 418 } 419 Object checkReceiver(Object recv) { 420 if (!caller.isInstance(recv)) { 421 String msg = String.format("Receiver class %s is not a subclass of caller class %s", 422 recv.getClass().getName(), caller.getName()); 423 throw new IncompatibleClassChangeError(msg); 424 } 425 return recv; 426 } 427 } 428 429 /** This subclass represents invokeinterface instructions. */ 430 static class Interface extends DirectMethodHandle { 431 private final Class<?> refc; 432 private Interface(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> refc) { 433 super(mtype, form, member, crackable); 434 assert(refc.isInterface()) : refc; 435 this.refc = refc; 436 } 437 @Override 438 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 439 return new Interface(mt, lf, member, crackable, refc); 440 } 441 @Override 442 MethodHandle viewAsType(MethodType newType, boolean strict) { 443 assert(viewAsTypeChecks(newType, strict)); 444 return new Interface(newType, form, member, false, refc); 445 } 446 @Override 447 Object checkReceiver(Object recv) { 448 if (!refc.isInstance(recv)) { 449 String msg = String.format("Receiver class %s does not implement the requested interface %s", 450 recv.getClass().getName(), refc.getName()); 451 throw new IncompatibleClassChangeError(msg); 452 } 453 return recv; 454 } 455 } 456 457 /** Used for interface receiver type checks, by Interface and Special modes. */ 458 Object checkReceiver(Object recv) { 459 throw new InternalError("Should only be invoked on a subclass"); 460 } 461 462 /** This subclass handles constructor references. */ 463 static class Constructor extends DirectMethodHandle { 464 final MemberName initMethod; 465 final Class<?> instanceClass; 466 467 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor, 468 boolean crackable, MemberName initMethod, Class<?> instanceClass) { 469 super(mtype, form, constructor, crackable); 470 this.initMethod = initMethod; 471 this.instanceClass = instanceClass; 472 assert(initMethod.isResolved()); 473 } 474 @Override 475 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 476 return new Constructor(mt, lf, member, crackable, initMethod, instanceClass); 477 } 478 @Override 479 MethodHandle viewAsType(MethodType newType, boolean strict) { 480 assert(viewAsTypeChecks(newType, strict)); 481 return new Constructor(newType, form, member, false, initMethod, instanceClass); 482 } 483 } 484 485 /*non-public*/ 486 static Object constructorMethod(Object mh) { 487 Constructor dmh = (Constructor)mh; 488 return dmh.initMethod; 489 } 490 491 /*non-public*/ 492 static Object allocateInstance(Object mh) throws InstantiationException { 493 Constructor dmh = (Constructor)mh; 494 return UNSAFE.allocateInstance(dmh.instanceClass); 495 } 496 497 /** This subclass handles non-static field references. */ 498 static class Accessor extends DirectMethodHandle { 499 final Class<?> fieldType; 500 final int fieldOffset; 501 private Accessor(MethodType mtype, LambdaForm form, MemberName member, 502 boolean crackable, int fieldOffset) { 503 super(mtype, form, member, crackable); 504 this.fieldType = member.getFieldType(); 505 this.fieldOffset = fieldOffset; 506 } 507 508 @Override Object checkCast(Object obj) { 509 return fieldType.cast(obj); 510 } 511 @Override 512 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 513 return new Accessor(mt, lf, member, crackable, fieldOffset); 514 } 515 @Override 516 MethodHandle viewAsType(MethodType newType, boolean strict) { 517 assert(viewAsTypeChecks(newType, strict)); 518 return new Accessor(newType, form, member, false, fieldOffset); 519 } 520 } 521 522 @ForceInline 523 /*non-public*/ 524 static long fieldOffset(Object accessorObj) { 525 // Note: We return a long because that is what Unsafe.getObject likes. 526 // We store a plain int because it is more compact. 527 return ((Accessor)accessorObj).fieldOffset; 528 } 529 530 @ForceInline 531 /*non-public*/ 532 static Object checkBase(Object obj) { 533 // Note that the object's class has already been verified, 534 // since the parameter type of the Accessor method handle 535 // is either member.getDeclaringClass or a subclass. 536 // This was verified in DirectMethodHandle.make. 537 // Therefore, the only remaining check is for null. 538 // Since this check is *not* guaranteed by Unsafe.getInt 539 // and its siblings, we need to make an explicit one here. 540 return Objects.requireNonNull(obj); 541 } 542 543 static class StaticAccessor extends DirectMethodHandle { 544 final Class<?> fieldType; 545 final Object staticBase; 546 final long staticOffset; 547 548 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member, 549 boolean crackable, Object staticBase, long staticOffset) { 550 super(mtype, form, member, crackable); 551 this.fieldType = member.getFieldType(); 552 this.staticBase = staticBase; 553 this.staticOffset = staticOffset; 554 } 555 556 @Override Object checkCast(Object obj) { 557 return fieldType.cast(obj); 558 } 559 @Override 560 MethodHandle copyWith(MethodType mt, LambdaForm lf) { 561 return new StaticAccessor(mt, lf, member, crackable, staticBase, staticOffset); 562 } 563 @Override 564 MethodHandle viewAsType(MethodType newType, boolean strict) { 565 assert(viewAsTypeChecks(newType, strict)); 566 return new StaticAccessor(newType, form, member, false, staticBase, staticOffset); 567 } 568 } 569 570 @ForceInline 571 /*non-public*/ 572 static Object nullCheck(Object obj) { 573 return Objects.requireNonNull(obj); 574 } 575 576 @ForceInline 577 /*non-public*/ 578 static Object staticBase(Object accessorObj) { 579 return ((StaticAccessor)accessorObj).staticBase; 580 } 581 582 @ForceInline 583 /*non-public*/ 584 static long staticOffset(Object accessorObj) { 585 return ((StaticAccessor)accessorObj).staticOffset; 586 } 587 588 @ForceInline 589 /*non-public*/ 590 static Object checkCast(Object mh, Object obj) { 591 return ((DirectMethodHandle) mh).checkCast(obj); 592 } 593 594 @ForceInline 595 /*non-public*/ static Class<?> fieldType(Object accessorObj) { 596 return ((Accessor) accessorObj).fieldType; 597 } 598 599 @ForceInline 600 /*non-public*/ static Class<?> staticFieldType(Object accessorObj) { 601 return ((StaticAccessor) accessorObj).fieldType; 602 } 603 604 Object checkCast(Object obj) { 605 return member.getReturnType().cast(obj); 606 } 607 608 // Caching machinery for field accessors: 609 static final byte 610 AF_GETFIELD = 0, 611 AF_PUTFIELD = 1, 612 AF_GETSTATIC = 2, 613 AF_PUTSTATIC = 3, 614 AF_GETSTATIC_INIT = 4, 615 AF_PUTSTATIC_INIT = 5, 616 AF_LIMIT = 6; 617 // Enumerate the different field kinds using Wrapper, 618 // with an extra case added for checked references and value field access 619 static final int 620 FT_LAST_WRAPPER = Wrapper.COUNT-1, 621 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(), 622 FT_CHECKED_REF = FT_LAST_WRAPPER+1, 623 FT_CHECKED_VALUE = FT_LAST_WRAPPER+2, // flattened and non-flattened 624 FT_LIMIT = FT_LAST_WRAPPER+4; 625 private static int afIndex(byte formOp, boolean isVolatile, boolean isFlatValue, int ftypeKind) { 626 return ((formOp * FT_LIMIT * 2) 627 + (isVolatile ? FT_LIMIT : 0) 628 + (isFlatValue ? 1 : 0) 629 + ftypeKind); 630 } 631 @Stable 632 private static final LambdaForm[] ACCESSOR_FORMS 633 = new LambdaForm[afIndex(AF_LIMIT, false, false, 0)]; 634 static int ftypeKind(Class<?> ftype, boolean isValue) { 635 if (ftype.isPrimitive()) 636 return Wrapper.forPrimitiveType(ftype).ordinal(); 637 else if (VerifyType.isNullReferenceConversion(Object.class, ftype)) { 638 return FT_UNCHECKED_REF; 639 } else 640 // null check for value type in addition to check cast 641 return isValue ? FT_CHECKED_VALUE : FT_CHECKED_REF; 642 } 643 644 /** 645 * Create a LF which can access the given field. 646 * Cache and share this structure among all fields with 647 * the same basicType and refKind. 648 */ 649 private static LambdaForm preparedFieldLambdaForm(MemberName m) { 650 Class<?> ftype = m.getFieldType(); 651 boolean isVolatile = m.isVolatile(); 652 byte formOp = switch (m.getReferenceKind()) { 653 case REF_getField -> AF_GETFIELD; 654 case REF_putField -> AF_PUTFIELD; 655 case REF_getStatic -> AF_GETSTATIC; 656 case REF_putStatic -> AF_PUTSTATIC; 657 default -> throw new InternalError(m.toString()); 658 }; 659 if (shouldBeInitialized(m)) { 660 // precompute the barrier-free version: 661 preparedFieldLambdaForm(formOp, m.isVolatile(), m.isInlineableField(), m.isFlattened(), ftype); 662 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) == 663 (AF_PUTSTATIC_INIT - AF_PUTSTATIC)); 664 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC); 665 } 666 LambdaForm lform = preparedFieldLambdaForm(formOp, m.isVolatile(), m.isInlineableField(), m.isFlattened(), ftype); 667 maybeCompile(lform, m); 668 assert(lform.methodType().dropParameterTypes(0, 1) 669 .equals(m.getInvocationType().basicType())) 670 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType()); 671 return lform; 672 } 673 674 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isValue, boolean isFlatValue, Class<?> ftype) { 675 int ftypeKind = ftypeKind(ftype, isValue); 676 int afIndex = afIndex(formOp, isVolatile, isFlatValue, ftypeKind); 677 LambdaForm lform = ACCESSOR_FORMS[afIndex]; 678 if (lform != null) return lform; 679 lform = makePreparedFieldLambdaForm(formOp, isVolatile, isValue, isFlatValue, ftypeKind); 680 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS 681 return lform; 682 } 683 684 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values(); 685 686 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, boolean isFlatValue, Wrapper wrapper) { 687 if (isGetter) { 688 if (isVolatile) { 689 switch (wrapper) { 690 case BOOLEAN: return GET_BOOLEAN_VOLATILE; 691 case BYTE: return GET_BYTE_VOLATILE; 692 case SHORT: return GET_SHORT_VOLATILE; 693 case CHAR: return GET_CHAR_VOLATILE; 694 case INT: return GET_INT_VOLATILE; 695 case LONG: return GET_LONG_VOLATILE; 696 case FLOAT: return GET_FLOAT_VOLATILE; 697 case DOUBLE: return GET_DOUBLE_VOLATILE; 698 case OBJECT: return isFlatValue ? GET_VALUE_VOLATILE : GET_REFERENCE_VOLATILE; 699 } 700 } else { 701 switch (wrapper) { 702 case BOOLEAN: return GET_BOOLEAN; 703 case BYTE: return GET_BYTE; 704 case SHORT: return GET_SHORT; 705 case CHAR: return GET_CHAR; 706 case INT: return GET_INT; 707 case LONG: return GET_LONG; 708 case FLOAT: return GET_FLOAT; 709 case DOUBLE: return GET_DOUBLE; 710 case OBJECT: return isFlatValue ? GET_VALUE : GET_REFERENCE; 711 } 712 } 713 } else { 714 if (isVolatile) { 715 switch (wrapper) { 716 case BOOLEAN: return PUT_BOOLEAN_VOLATILE; 717 case BYTE: return PUT_BYTE_VOLATILE; 718 case SHORT: return PUT_SHORT_VOLATILE; 719 case CHAR: return PUT_CHAR_VOLATILE; 720 case INT: return PUT_INT_VOLATILE; 721 case LONG: return PUT_LONG_VOLATILE; 722 case FLOAT: return PUT_FLOAT_VOLATILE; 723 case DOUBLE: return PUT_DOUBLE_VOLATILE; 724 case OBJECT: return isFlatValue ? PUT_VALUE_VOLATILE : PUT_REFERENCE_VOLATILE; 725 } 726 } else { 727 switch (wrapper) { 728 case BOOLEAN: return PUT_BOOLEAN; 729 case BYTE: return PUT_BYTE; 730 case SHORT: return PUT_SHORT; 731 case CHAR: return PUT_CHAR; 732 case INT: return PUT_INT; 733 case LONG: return PUT_LONG; 734 case FLOAT: return PUT_FLOAT; 735 case DOUBLE: return PUT_DOUBLE; 736 case OBJECT: return isFlatValue ? PUT_VALUE : PUT_REFERENCE; 737 } 738 } 739 } 740 throw new AssertionError("Invalid arguments"); 741 } 742 743 /** invoked by GenerateJLIClassesHelper */ 744 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftype) { 745 return makePreparedFieldLambdaForm(formOp, isVolatile, false, false, ftype); 746 } 747 748 private static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isValue, boolean isFlatValue, int ftypeKind) { 749 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1); 750 boolean isStatic = (formOp >= AF_GETSTATIC); 751 boolean needsInit = (formOp >= AF_GETSTATIC_INIT); 752 boolean needsCast = (ftypeKind == FT_CHECKED_REF || ftypeKind == FT_CHECKED_VALUE); 753 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]); 754 Class<?> ft = fw.primitiveType(); 755 assert(needsCast ? true : ftypeKind(ft, isValue) == ftypeKind); 756 757 // getObject, putIntVolatile, etc. 758 Kind kind = getFieldKind(isGetter, isVolatile, isFlatValue, fw); 759 760 MethodType linkerType; 761 boolean hasValueTypeArg = isGetter ? isValue : isFlatValue; 762 if (isGetter) { 763 linkerType = isValue ? MethodType.methodType(ft, Object.class, long.class, Class.class) 764 : MethodType.methodType(ft, Object.class, long.class); 765 } else { 766 linkerType = isFlatValue ? MethodType.methodType(void.class, Object.class, long.class, Class.class, ft) 767 : MethodType.methodType(void.class, Object.class, long.class, ft); 768 } 769 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual); 770 try { 771 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, LM_TRUSTED, 772 NoSuchMethodException.class); 773 } catch (ReflectiveOperationException ex) { 774 throw newInternalError(ex); 775 } 776 777 // What is the external type of the lambda form? 778 MethodType mtype; 779 if (isGetter) 780 mtype = MethodType.methodType(ft); 781 else 782 mtype = MethodType.methodType(void.class, ft); 783 mtype = mtype.basicType(); // erase short to int, etc. 784 if (!isStatic) 785 mtype = mtype.insertParameterTypes(0, Object.class); 786 final int DMH_THIS = 0; 787 final int ARG_BASE = 1; 788 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount(); 789 // if this is for non-static access, the base pointer is stored at this index: 790 final int OBJ_BASE = isStatic ? -1 : ARG_BASE; 791 // if this is for write access, the value to be written is stored at this index: 792 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1; 793 int nameCursor = ARG_LIMIT; 794 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any 795 final int F_OFFSET = nameCursor++; // Either static offset or field offset. 796 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1); 797 final int U_HOLDER = nameCursor++; // UNSAFE holder 798 final int INIT_BAR = (needsInit ? nameCursor++ : -1); 799 final int VALUE_TYPE = (hasValueTypeArg ? nameCursor++ : -1); 800 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1); 801 final int LINKER_CALL = nameCursor++; 802 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1); 803 final int RESULT = nameCursor-1; // either the call or the cast 804 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType()); 805 if (needsInit) 806 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]); 807 if (needsCast && !isGetter) 808 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]); 809 Object[] outArgs = new Object[1 + linkerType.parameterCount()]; 810 assert (outArgs.length == (isGetter ? 3 : 4) + (hasValueTypeArg ? 1 : 0)); 811 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE)); 812 if (isStatic) { 813 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]); 814 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]); 815 } else { 816 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]); 817 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]); 818 } 819 int x = 3; 820 if (hasValueTypeArg) { 821 outArgs[x++] = names[VALUE_TYPE] = isStatic ? new Name(getFunction(NF_staticFieldType), names[DMH_THIS]) 822 : new Name(getFunction(NF_fieldType), names[DMH_THIS]); 823 } 824 if (!isGetter) { 825 outArgs[x] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]); 826 } 827 for (Object a : outArgs) assert(a != null); 828 names[LINKER_CALL] = new Name(linker, outArgs); 829 if (needsCast && isGetter) 830 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]); 831 for (Name n : names) assert(n != null); 832 833 LambdaForm form; 834 if (needsCast || needsInit) { 835 // can't use the pre-generated form when casting and/or initializing 836 form = new LambdaForm(ARG_LIMIT, names, RESULT); 837 } else { 838 form = new LambdaForm(ARG_LIMIT, names, RESULT, kind); 839 } 840 841 if (LambdaForm.debugNames()) { 842 // add some detail to the lambdaForm debugname, 843 // significant only for debugging 844 StringBuilder nameBuilder = new StringBuilder(kind.methodName); 845 if (isStatic) { 846 nameBuilder.append("Static"); 847 } else { 848 nameBuilder.append("Field"); 849 } 850 if (needsCast) { 851 nameBuilder.append("Cast"); 852 } 853 if (needsInit) { 854 nameBuilder.append("Init"); 855 } 856 LambdaForm.associateWithDebugName(form, nameBuilder.toString()); 857 } 858 return form; 859 } 860 861 /** 862 * Pre-initialized NamedFunctions for bootstrapping purposes. 863 */ 864 static final byte NF_internalMemberName = 0, 865 NF_internalMemberNameEnsureInit = 1, 866 NF_ensureInitialized = 2, 867 NF_fieldOffset = 3, 868 NF_checkBase = 4, 869 NF_staticBase = 5, 870 NF_staticOffset = 6, 871 NF_checkCast = 7, 872 NF_allocateInstance = 8, 873 NF_constructorMethod = 9, 874 NF_UNSAFE = 10, 875 NF_checkReceiver = 11, 876 NF_fieldType = 12, 877 NF_staticFieldType = 13, 878 NF_LIMIT = 14; 879 880 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT]; 881 882 private static NamedFunction getFunction(byte func) { 883 NamedFunction nf = NFS[func]; 884 if (nf != null) { 885 return nf; 886 } 887 // Each nf must be statically invocable or we get tied up in our bootstraps. 888 nf = NFS[func] = createFunction(func); 889 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf)); 890 return nf; 891 } 892 893 private static final MethodType CLS_OBJ_TYPE = MethodType.methodType(Class.class, Object.class); 894 895 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class); 896 897 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class); 898 899 private static NamedFunction createFunction(byte func) { 900 try { 901 switch (func) { 902 case NF_internalMemberName: 903 return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE); 904 case NF_internalMemberNameEnsureInit: 905 return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE); 906 case NF_ensureInitialized: 907 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class)); 908 case NF_fieldOffset: 909 return getNamedFunction("fieldOffset", LONG_OBJ_TYPE); 910 case NF_checkBase: 911 return getNamedFunction("checkBase", OBJ_OBJ_TYPE); 912 case NF_staticBase: 913 return getNamedFunction("staticBase", OBJ_OBJ_TYPE); 914 case NF_staticOffset: 915 return getNamedFunction("staticOffset", LONG_OBJ_TYPE); 916 case NF_checkCast: 917 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class)); 918 case NF_allocateInstance: 919 return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE); 920 case NF_constructorMethod: 921 return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE); 922 case NF_UNSAFE: 923 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getField); 924 return new NamedFunction( 925 MemberName.getFactory().resolveOrFail(REF_getField, member, 926 DirectMethodHandle.class, LM_TRUSTED, 927 NoSuchMethodException.class)); 928 case NF_checkReceiver: 929 member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual); 930 return new NamedFunction( 931 MemberName.getFactory().resolveOrFail(REF_invokeVirtual, member, 932 DirectMethodHandle.class, LM_TRUSTED, 933 NoSuchMethodException.class)); 934 case NF_fieldType: 935 return getNamedFunction("fieldType", CLS_OBJ_TYPE); 936 case NF_staticFieldType: 937 return getNamedFunction("staticFieldType", CLS_OBJ_TYPE); 938 default: 939 throw newInternalError("Unknown function: " + func); 940 } 941 } catch (ReflectiveOperationException ex) { 942 throw newInternalError(ex); 943 } 944 } 945 946 private static NamedFunction getNamedFunction(String name, MethodType type) 947 throws ReflectiveOperationException 948 { 949 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic); 950 return new NamedFunction( 951 MemberName.getFactory().resolveOrFail(REF_invokeStatic, member, 952 DirectMethodHandle.class, LM_TRUSTED, 953 NoSuchMethodException.class)); 954 } 955 956 static { 957 // The Holder class will contain pre-generated DirectMethodHandles resolved 958 // speculatively using MemberName.getFactory().resolveOrNull. However, that 959 // doesn't initialize the class, which subtly breaks inlining etc. By forcing 960 // initialization of the Holder class we avoid these issues. 961 UNSAFE.ensureClassInitialized(Holder.class); 962 } 963 964 /* Placeholder class for DirectMethodHandles generated ahead of time */ 965 final class Holder {} 966 }