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.ref.CleanerFactory; 29 import sun.invoke.util.Wrapper; 30 31 import java.lang.invoke.MethodHandles.Lookup; 32 import java.lang.reflect.Field; 33 34 import static java.lang.invoke.MethodHandleNatives.Constants.*; 35 import static java.lang.invoke.MethodHandleStatics.TRACE_METHOD_LINKAGE; 36 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP; 37 38 /** 39 * The JVM interface for the method handles package is all here. 40 * This is an interface internal and private to an implementation of JSR 292. 41 * <em>This class is not part of the JSR 292 standard.</em> 42 * @author jrose 43 */ 44 class MethodHandleNatives { 45 46 private MethodHandleNatives() { } // static only 47 48 /// MemberName support 49 50 static native void init(MemberName self, Object ref); 51 static native void expand(MemberName self); 52 static native MemberName resolve(MemberName self, Class<?> caller, 53 boolean speculativeResolve) throws LinkageError, ClassNotFoundException; 54 static native int getMembers(Class<?> defc, String matchName, String matchSig, 55 int matchFlags, Class<?> caller, int skip, MemberName[] results); 56 57 /// Field layout queries parallel to jdk.internal.misc.Unsafe: 58 static native long objectFieldOffset(MemberName self); // e.g., returns vmindex 59 static native long staticFieldOffset(MemberName self); // e.g., returns vmindex 60 static native Object staticFieldBase(MemberName self); // e.g., returns clazz 61 static native Object getMemberVMInfo(MemberName self); // returns {vmindex,vmtarget} 62 63 /// CallSite support 64 65 /** Tell the JVM that we need to change the target of a CallSite. */ 66 static native void setCallSiteTargetNormal(CallSite site, MethodHandle target); 67 static native void setCallSiteTargetVolatile(CallSite site, MethodHandle target); 68 69 static native void copyOutBootstrapArguments(Class<?> caller, int[] indexInfo, 70 int start, int end, 71 Object[] buf, int pos, 72 boolean resolve, 73 Object ifNotAvailable); 74 75 /** Represents a context to track nmethod dependencies on CallSite instance target. */ 76 static class CallSiteContext implements Runnable { 77 //@Injected JVM_nmethodBucket* vmdependencies; 78 79 static CallSiteContext make(CallSite cs) { 80 final CallSiteContext newContext = new CallSiteContext(); 81 // CallSite instance is tracked by a Cleanable which clears native 82 // structures allocated for CallSite context. Though the CallSite can 83 // become unreachable, its Context is retained by the Cleanable instance 84 // (which is referenced from Cleaner instance which is referenced from 85 // CleanerFactory class) until cleanup is performed. 86 CleanerFactory.cleaner().register(cs, newContext); 87 return newContext; 88 } 89 90 @Override 91 public void run() { 92 MethodHandleNatives.clearCallSiteContext(this); 93 } 94 } 95 96 /** Invalidate all recorded nmethods. */ 97 private static native void clearCallSiteContext(CallSiteContext context); 98 99 private static native void registerNatives(); 100 static { 101 registerNatives(); 102 } 103 104 /** 105 * Compile-time constants go here. This collection exists not only for 106 * reference from clients, but also for ensuring the VM and JDK agree on the 107 * values of these constants (see {@link #verifyConstants()}). 108 */ 109 static class Constants { 110 Constants() { } // static only 111 112 static final int 113 MN_IS_METHOD = 0x00010000, // method (not constructor) 114 MN_IS_CONSTRUCTOR = 0x00020000, // constructor 115 MN_IS_FIELD = 0x00040000, // field 116 MN_IS_TYPE = 0x00080000, // nested type 117 MN_CALLER_SENSITIVE = 0x00100000, // @CallerSensitive annotation detected 118 MN_REFERENCE_KIND_SHIFT = 24, // refKind 119 MN_REFERENCE_KIND_MASK = 0x0F000000 >> MN_REFERENCE_KIND_SHIFT, 120 // The SEARCH_* bits are not for MN.flags but for the matchFlags argument of MHN.getMembers: 121 MN_SEARCH_SUPERCLASSES = 0x00100000, 122 MN_SEARCH_INTERFACES = 0x00200000; 123 124 /** 125 * Constant pool reference-kind codes, as used by CONSTANT_MethodHandle CP entries. 126 */ 127 static final byte 128 REF_NONE = 0, // null value 129 REF_getField = 1, 130 REF_getStatic = 2, 131 REF_putField = 3, 132 REF_putStatic = 4, 133 REF_invokeVirtual = 5, 134 REF_invokeStatic = 6, 135 REF_invokeSpecial = 7, 136 REF_newInvokeSpecial = 8, 137 REF_invokeInterface = 9, 138 REF_LIMIT = 10; 139 } 140 141 static boolean refKindIsValid(int refKind) { 142 return (refKind > REF_NONE && refKind < REF_LIMIT); 143 } 144 static boolean refKindIsField(byte refKind) { 145 assert(refKindIsValid(refKind)); 146 return (refKind <= REF_putStatic); 147 } 148 static boolean refKindIsGetter(byte refKind) { 149 assert(refKindIsValid(refKind)); 150 return (refKind <= REF_getStatic); 151 } 152 static boolean refKindIsSetter(byte refKind) { 153 return refKindIsField(refKind) && !refKindIsGetter(refKind); 154 } 155 static boolean refKindIsMethod(byte refKind) { 156 return !refKindIsField(refKind) && (refKind != REF_newInvokeSpecial); 157 } 158 static boolean refKindIsConstructor(byte refKind) { 159 return (refKind == REF_newInvokeSpecial); 160 } 161 static boolean refKindHasReceiver(byte refKind) { 162 assert(refKindIsValid(refKind)); 163 return (refKind & 1) != 0; 164 } 165 static boolean refKindIsStatic(byte refKind) { 166 return !refKindHasReceiver(refKind) && (refKind != REF_newInvokeSpecial); 167 } 168 static boolean refKindDoesDispatch(byte refKind) { 169 assert(refKindIsValid(refKind)); 170 return (refKind == REF_invokeVirtual || 171 refKind == REF_invokeInterface); 172 } 173 static { 174 final int HR_MASK = ((1 << REF_getField) | 175 (1 << REF_putField) | 176 (1 << REF_invokeVirtual) | 177 (1 << REF_invokeSpecial) | 178 (1 << REF_invokeInterface) 179 ); 180 for (byte refKind = REF_NONE+1; refKind < REF_LIMIT; refKind++) { 181 assert(refKindHasReceiver(refKind) == (((1<<refKind) & HR_MASK) != 0)) : refKind; 182 } 183 } 184 static String refKindName(byte refKind) { 185 assert(refKindIsValid(refKind)); 186 switch (refKind) { 187 case REF_getField: return "getField"; 188 case REF_getStatic: return "getStatic"; 189 case REF_putField: return "putField"; 190 case REF_putStatic: return "putStatic"; 191 case REF_invokeVirtual: return "invokeVirtual"; 192 case REF_invokeStatic: return "invokeStatic"; 193 case REF_invokeSpecial: return "invokeSpecial"; 194 case REF_newInvokeSpecial: return "newInvokeSpecial"; 195 case REF_invokeInterface: return "invokeInterface"; 196 default: return "REF_???"; 197 } 198 } 199 200 private static native int getNamedCon(int which, Object[] name); 201 static boolean verifyConstants() { 202 Object[] box = { null }; 203 for (int i = 0; ; i++) { 204 box[0] = null; 205 int vmval = getNamedCon(i, box); 206 if (box[0] == null) break; 207 String name = (String) box[0]; 208 try { 209 Field con = Constants.class.getDeclaredField(name); 210 int jval = con.getInt(null); 211 if (jval == vmval) continue; 212 String err = (name+": JVM has "+vmval+" while Java has "+jval); 213 if (name.equals("CONV_OP_LIMIT")) { 214 System.err.println("warning: "+err); 215 continue; 216 } 217 throw new InternalError(err); 218 } catch (NoSuchFieldException | IllegalAccessException ex) { 219 String err = (name+": JVM has "+vmval+" which Java does not define"); 220 // ignore exotic ops the JVM cares about; we just wont issue them 221 //System.err.println("warning: "+err); 222 continue; 223 } 224 } 225 return true; 226 } 227 static { 228 assert(verifyConstants()); 229 } 230 231 // Up-calls from the JVM. 232 // These must NOT be public. 233 234 /** 235 * The JVM is linking an invokedynamic instruction. Create a reified call site for it. 236 */ 237 static MemberName linkCallSite(Object callerObj, 238 int indexInCP, 239 Object bootstrapMethodObj, 240 Object nameObj, Object typeObj, 241 Object staticArguments, 242 Object[] appendixResult) { 243 MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj; 244 Class<?> caller = (Class<?>)callerObj; 245 String name = nameObj.toString().intern(); 246 MethodType type = (MethodType)typeObj; 247 if (!TRACE_METHOD_LINKAGE) 248 return linkCallSiteImpl(caller, bootstrapMethod, name, type, 249 staticArguments, appendixResult); 250 return linkCallSiteTracing(caller, bootstrapMethod, name, type, 251 staticArguments, appendixResult); 252 } 253 static MemberName linkCallSiteImpl(Class<?> caller, 254 MethodHandle bootstrapMethod, 255 String name, MethodType type, 256 Object staticArguments, 257 Object[] appendixResult) { 258 CallSite callSite = CallSite.makeSite(bootstrapMethod, 259 name, 260 type, 261 staticArguments, 262 caller); 263 if (callSite instanceof ConstantCallSite) { 264 appendixResult[0] = callSite.dynamicInvoker(); 265 return Invokers.linkToTargetMethod(type); 266 } else { 267 appendixResult[0] = callSite; 268 return Invokers.linkToCallSiteMethod(type); 269 } 270 } 271 // Tracing logic: 272 static MemberName linkCallSiteTracing(Class<?> caller, 273 MethodHandle bootstrapMethod, 274 String name, MethodType type, 275 Object staticArguments, 276 Object[] appendixResult) { 277 Object bsmReference = bootstrapMethod.internalMemberName(); 278 if (bsmReference == null) bsmReference = bootstrapMethod; 279 String staticArglist = staticArglistForTrace(staticArguments); 280 System.out.println("linkCallSite "+caller.getName()+" "+ 281 bsmReference+" "+ 282 name+type+"/"+staticArglist); 283 try { 284 MemberName res = linkCallSiteImpl(caller, bootstrapMethod, name, type, 285 staticArguments, appendixResult); 286 System.out.println("linkCallSite => "+res+" + "+appendixResult[0]); 287 return res; 288 } catch (Throwable ex) { 289 ex.printStackTrace(); // print now in case exception is swallowed 290 System.out.println("linkCallSite => throw "+ex); 291 throw ex; 292 } 293 } 294 295 // this implements the upcall from the JVM, MethodHandleNatives.linkDynamicConstant: 296 static Object linkDynamicConstant(Object callerObj, 297 int indexInCP, 298 Object bootstrapMethodObj, 299 Object nameObj, Object typeObj, 300 Object staticArguments) { 301 MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj; 302 Class<?> caller = (Class<?>)callerObj; 303 String name = nameObj.toString().intern(); 304 Class<?> type = (Class<?>)typeObj; 305 if (!TRACE_METHOD_LINKAGE) 306 return linkDynamicConstantImpl(caller, bootstrapMethod, name, type, staticArguments); 307 return linkDynamicConstantTracing(caller, bootstrapMethod, name, type, staticArguments); 308 } 309 310 static Object linkDynamicConstantImpl(Class<?> caller, 311 MethodHandle bootstrapMethod, 312 String name, Class<?> type, 313 Object staticArguments) { 314 return ConstantBootstraps.makeConstant(bootstrapMethod, name, type, staticArguments, caller); 315 } 316 317 private static String staticArglistForTrace(Object staticArguments) { 318 if (staticArguments instanceof Object[]) 319 return "BSA="+java.util.Arrays.asList((Object[]) staticArguments); 320 if (staticArguments instanceof int[]) 321 return "BSA@"+java.util.Arrays.toString((int[]) staticArguments); 322 if (staticArguments == null) 323 return "BSA0=null"; 324 return "BSA1="+staticArguments; 325 } 326 327 // Tracing logic: 328 static Object linkDynamicConstantTracing(Class<?> caller, 329 MethodHandle bootstrapMethod, 330 String name, Class<?> type, 331 Object staticArguments) { 332 Object bsmReference = bootstrapMethod.internalMemberName(); 333 if (bsmReference == null) bsmReference = bootstrapMethod; 334 String staticArglist = staticArglistForTrace(staticArguments); 335 System.out.println("linkDynamicConstant "+caller.getName()+" "+ 336 bsmReference+" "+ 337 name+type+"/"+staticArglist); 338 try { 339 Object res = linkDynamicConstantImpl(caller, bootstrapMethod, name, type, staticArguments); 340 System.out.println("linkDynamicConstantImpl => "+res); 341 return res; 342 } catch (Throwable ex) { 343 ex.printStackTrace(); // print now in case exception is swallowed 344 System.out.println("linkDynamicConstant => throw "+ex); 345 throw ex; 346 } 347 } 348 349 /** The JVM is requesting pull-mode bootstrap when it provides 350 * a tuple of the form int[]{ argc, vmindex }. 351 * The BSM is expected to call back to the JVM using the caller 352 * class and vmindex to resolve the static arguments. 353 */ 354 static boolean staticArgumentsPulled(Object staticArguments) { 355 return staticArguments instanceof int[]; 356 } 357 358 /** A BSM runs in pull-mode if and only if its sole arguments 359 * are (Lookup, BootstrapCallInfo), or can be converted pairwise 360 * to those types, and it is not of variable arity. 361 * Excluding error cases, we can just test that the arity is a constant 2. 362 * 363 * NOTE: This method currently returns false, since pulling is not currently 364 * exposed to a BSM. When pull mode is supported the method block will be 365 * replaced with currently commented out code. 366 */ 367 static boolean isPullModeBSM(MethodHandle bsm) { 368 return false; 369 // return bsm.type().parameterCount() == 2 && !bsm.isVarargsCollector(); 370 } 371 372 /** 373 * The JVM wants a pointer to a MethodType. Oblige it by finding or creating one. 374 */ 375 static MethodType findMethodHandleType(Class<?> rtype, Class<?>[] ptypes) { 376 return MethodType.makeImpl(rtype, ptypes, true); 377 } 378 379 /** 380 * The JVM wants to link a call site that requires a dynamic type check. 381 * Name is a type-checking invoker, invokeExact or invoke. 382 * Return a JVM method (MemberName) to handle the invoking. 383 * The method assumes the following arguments on the stack: 384 * 0: the method handle being invoked 385 * 1-N: the arguments to the method handle invocation 386 * N+1: an optional, implicitly added argument (typically the given MethodType) 387 * <p> 388 * The nominal method at such a call site is an instance of 389 * a signature-polymorphic method (see @PolymorphicSignature). 390 * Such method instances are user-visible entities which are 391 * "split" from the generic placeholder method in {@code MethodHandle}. 392 * (Note that the placeholder method is not identical with any of 393 * its instances. If invoked reflectively, is guaranteed to throw an 394 * {@code UnsupportedOperationException}.) 395 * If the signature-polymorphic method instance is ever reified, 396 * it appears as a "copy" of the original placeholder 397 * (a native final member of {@code MethodHandle}) except 398 * that its type descriptor has shape required by the instance, 399 * and the method instance is <em>not</em> varargs. 400 * The method instance is also marked synthetic, since the 401 * method (by definition) does not appear in Java source code. 402 * <p> 403 * The JVM is allowed to reify this method as instance metadata. 404 * For example, {@code invokeBasic} is always reified. 405 * But the JVM may instead call {@code linkMethod}. 406 * If the result is an * ordered pair of a {@code (method, appendix)}, 407 * the method gets all the arguments (0..N inclusive) 408 * plus the appendix (N+1), and uses the appendix to complete the call. 409 * In this way, one reusable method (called a "linker method") 410 * can perform the function of any number of polymorphic instance 411 * methods. 412 * <p> 413 * Linker methods are allowed to be weakly typed, with any or 414 * all references rewritten to {@code Object} and any primitives 415 * (except {@code long}/{@code float}/{@code double}) 416 * rewritten to {@code int}. 417 * A linker method is trusted to return a strongly typed result, 418 * according to the specific method type descriptor of the 419 * signature-polymorphic instance it is emulating. 420 * This can involve (as necessary) a dynamic check using 421 * data extracted from the appendix argument. 422 * <p> 423 * The JVM does not inspect the appendix, other than to pass 424 * it verbatim to the linker method at every call. 425 * This means that the JDK runtime has wide latitude 426 * for choosing the shape of each linker method and its 427 * corresponding appendix. 428 * Linker methods should be generated from {@code LambdaForm}s 429 * so that they do not become visible on stack traces. 430 * <p> 431 * The {@code linkMethod} call is free to omit the appendix 432 * (returning null) and instead emulate the required function 433 * completely in the linker method. 434 * As a corner case, if N==255, no appendix is possible. 435 * In this case, the method returned must be custom-generated to 436 * to perform any needed type checking. 437 * <p> 438 * If the JVM does not reify a method at a call site, but instead 439 * calls {@code linkMethod}, the corresponding call represented 440 * in the bytecodes may mention a valid method which is not 441 * representable with a {@code MemberName}. 442 * Therefore, use cases for {@code linkMethod} tend to correspond to 443 * special cases in reflective code such as {@code findVirtual} 444 * or {@code revealDirect}. 445 */ 446 static MemberName linkMethod(Class<?> callerClass, int refKind, 447 Class<?> defc, String name, Object type, 448 Object[] appendixResult) { 449 if (!TRACE_METHOD_LINKAGE) 450 return linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult); 451 return linkMethodTracing(callerClass, refKind, defc, name, type, appendixResult); 452 } 453 static MemberName linkMethodImpl(Class<?> callerClass, int refKind, 454 Class<?> defc, String name, Object type, 455 Object[] appendixResult) { 456 try { 457 if (refKind == REF_invokeVirtual) { 458 if (defc == MethodHandle.class) { 459 return Invokers.methodHandleInvokeLinkerMethod( 460 name, fixMethodType(callerClass, type), appendixResult); 461 } else if (defc == VarHandle.class) { 462 return varHandleOperationLinkerMethod( 463 name, fixMethodType(callerClass, type), appendixResult); 464 } 465 } 466 } catch (Error e) { 467 // Pass through an Error, including say StackOverflowError or 468 // OutOfMemoryError 469 throw e; 470 } catch (Throwable ex) { 471 // Wrap anything else in LinkageError 472 throw new LinkageError(ex.getMessage(), ex); 473 } 474 throw new LinkageError("no such method "+defc.getName()+"."+name+type); 475 } 476 private static MethodType fixMethodType(Class<?> callerClass, Object type) { 477 if (type instanceof MethodType) 478 return (MethodType) type; 479 else 480 return MethodType.fromDescriptor((String)type, callerClass.getClassLoader()); 481 } 482 // Tracing logic: 483 static MemberName linkMethodTracing(Class<?> callerClass, int refKind, 484 Class<?> defc, String name, Object type, 485 Object[] appendixResult) { 486 System.out.println("linkMethod "+defc.getName()+"."+ 487 name+type+"/"+Integer.toHexString(refKind)); 488 try { 489 MemberName res = linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult); 490 System.out.println("linkMethod => "+res+" + "+appendixResult[0]); 491 return res; 492 } catch (Throwable ex) { 493 System.out.println("linkMethod => throw "+ex); 494 throw ex; 495 } 496 } 497 498 /** 499 * Obtain the method to link to the VarHandle operation. 500 * This method is located here and not in Invokers to avoid 501 * intializing that and other classes early on in VM bootup. 502 */ 503 private static MemberName varHandleOperationLinkerMethod(String name, 504 MethodType mtype, 505 Object[] appendixResult) { 506 // Get the signature method type 507 final MethodType sigType = mtype.basicType(); 508 509 // Get the access kind from the method name 510 VarHandle.AccessMode ak; 511 try { 512 ak = VarHandle.AccessMode.valueFromMethodName(name); 513 } catch (IllegalArgumentException e) { 514 throw MethodHandleStatics.newInternalError(e); 515 } 516 517 // Create the appendix descriptor constant 518 VarHandle.AccessDescriptor ad = new VarHandle.AccessDescriptor(mtype, ak.at.ordinal(), ak.ordinal()); 519 appendixResult[0] = ad; 520 521 if (MethodHandleStatics.VAR_HANDLE_GUARDS) { 522 // If not polymorphic in the return type, such as the compareAndSet 523 // methods that return boolean 524 Class<?> guardReturnType = sigType.returnType(); 525 if (ak.at.isMonomorphicInReturnType) { 526 if (ak.at.returnType != mtype.returnType()) { 527 // The caller contains a different return type than that 528 // defined by the method 529 throw newNoSuchMethodErrorOnVarHandle(name, mtype); 530 } 531 // Adjust the return type of the signature method type 532 guardReturnType = ak.at.returnType; 533 } 534 535 // Get the guard method type for linking 536 final Class<?>[] guardParams = new Class<?>[sigType.parameterCount() + 2]; 537 // VarHandle at start 538 guardParams[0] = VarHandle.class; 539 for (int i = 0; i < sigType.parameterCount(); i++) { 540 guardParams[i + 1] = sigType.parameterType(i); 541 } 542 // Access descriptor at end 543 guardParams[guardParams.length - 1] = VarHandle.AccessDescriptor.class; 544 MethodType guardType = MethodType.makeImpl(guardReturnType, guardParams, true); 545 546 MemberName linker = new MemberName( 547 VarHandleGuards.class, getVarHandleGuardMethodName(guardType), 548 guardType, REF_invokeStatic); 549 550 linker = MemberName.getFactory().resolveOrNull(REF_invokeStatic, linker, 551 VarHandleGuards.class); 552 if (linker != null) { 553 return linker; 554 } 555 // Fall back to lambda form linkage if guard method is not available 556 // TODO Optionally log fallback ? 557 } 558 return Invokers.varHandleInvokeLinkerMethod(ak, mtype); 559 } 560 static String getVarHandleGuardMethodName(MethodType guardType) { 561 String prefix = "guard_"; 562 StringBuilder sb = new StringBuilder(prefix.length() + guardType.parameterCount()); 563 564 sb.append(prefix); 565 for (int i = 1; i < guardType.parameterCount() - 1; i++) { 566 Class<?> pt = guardType.parameterType(i); 567 sb.append(getCharErasedType(pt)); 568 } 569 sb.append('_').append(getCharErasedType(guardType.returnType())); 570 return sb.toString(); 571 } 572 static char getCharErasedType(Class<?> pt) { 573 return Wrapper.forBasicType(pt).basicTypeChar(); 574 } 575 static NoSuchMethodError newNoSuchMethodErrorOnVarHandle(String name, MethodType mtype) { 576 return new NoSuchMethodError("VarHandle." + name + mtype); 577 } 578 579 /** 580 * The JVM is resolving a CONSTANT_MethodHandle CP entry. And it wants our help. 581 * It will make an up-call to this method. (Do not change the name or signature.) 582 * The type argument is a Class for field requests and a MethodType for non-fields. 583 * <p> 584 * Recent versions of the JVM may also pass a resolved MemberName for the type. 585 * In that case, the name is ignored and may be null. 586 */ 587 static MethodHandle linkMethodHandleConstant(Class<?> callerClass, int refKind, 588 Class<?> defc, String name, Object type) { 589 try { 590 Lookup lookup = IMPL_LOOKUP.in(callerClass); 591 assert(refKindIsValid(refKind)); 592 return lookup.linkMethodHandleConstant((byte) refKind, defc, name, type); 593 } catch (ReflectiveOperationException ex) { 594 throw mapLookupExceptionToError(ex); 595 } 596 } 597 598 /** 599 * Map a reflective exception to a linkage error. 600 */ 601 static LinkageError mapLookupExceptionToError(ReflectiveOperationException ex) { 602 LinkageError err; 603 if (ex instanceof IllegalAccessException) { 604 Throwable cause = ex.getCause(); 605 if (cause instanceof AbstractMethodError) { 606 return (AbstractMethodError) cause; 607 } else { 608 err = new IllegalAccessError(ex.getMessage()); 609 } 610 } else if (ex instanceof NoSuchMethodException) { 611 err = new NoSuchMethodError(ex.getMessage()); 612 } else if (ex instanceof NoSuchFieldException) { 613 err = new NoSuchFieldError(ex.getMessage()); 614 } else { 615 err = new IncompatibleClassChangeError(); 616 } 617 return initCauseFrom(err, ex); 618 } 619 620 /** 621 * Use best possible cause for err.initCause(), substituting the 622 * cause for err itself if the cause has the same (or better) type. 623 */ 624 static <E extends Error> E initCauseFrom(E err, Exception ex) { 625 Throwable th = ex.getCause(); 626 @SuppressWarnings("unchecked") 627 final Class<E> Eclass = (Class<E>) err.getClass(); 628 if (Eclass.isInstance(th)) 629 return Eclass.cast(th); 630 err.initCause(th == null ? ex : th); 631 return err; 632 } 633 634 /** 635 * Is this method a caller-sensitive method? 636 * I.e., does it call Reflection.getCallerClass or a similar method 637 * to ask about the identity of its caller? 638 */ 639 static boolean isCallerSensitive(MemberName mem) { 640 if (!mem.isInvocable()) return false; // fields are not caller sensitive 641 642 return mem.isCallerSensitive() || canBeCalledVirtual(mem); 643 } 644 645 static boolean canBeCalledVirtual(MemberName mem) { 646 assert(mem.isInvocable()); 647 switch (mem.getName()) { 648 case "getContextClassLoader": 649 return canBeCalledVirtual(mem, java.lang.Thread.class); 650 } 651 return false; 652 } 653 654 static boolean canBeCalledVirtual(MemberName symbolicRef, Class<?> definingClass) { 655 Class<?> symbolicRefClass = symbolicRef.getDeclaringClass(); 656 if (symbolicRefClass == definingClass) return true; 657 if (symbolicRef.isStatic() || symbolicRef.isPrivate()) return false; 658 return (definingClass.isAssignableFrom(symbolicRefClass) || // Msym overrides Mdef 659 symbolicRefClass.isInterface()); // Mdef implements Msym 660 } 661 }