1 /* 2 * Copyright (c) 2008, 2019, 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 //@Injected jlong last_cleanup; 79 80 static CallSiteContext make(CallSite cs) { 81 final CallSiteContext newContext = new CallSiteContext(); 82 // CallSite instance is tracked by a Cleanable which clears native 83 // structures allocated for CallSite context. Though the CallSite can 84 // become unreachable, its Context is retained by the Cleanable instance 85 // (which is referenced from Cleaner instance which is referenced from 86 // CleanerFactory class) until cleanup is performed. 87 CleanerFactory.cleaner().register(cs, newContext); 88 return newContext; 89 } 90 91 @Override 92 public void run() { 93 MethodHandleNatives.clearCallSiteContext(this); 94 } 95 } 96 97 /** Invalidate all recorded nmethods. */ 98 private static native void clearCallSiteContext(CallSiteContext context); 99 100 private static native void registerNatives(); 101 static { 102 registerNatives(); 103 } 104 105 /** 106 * Compile-time constants go here. This collection exists not only for 107 * reference from clients, but also for ensuring the VM and JDK agree on the 108 * values of these constants (see {@link #verifyConstants()}). 109 */ 110 static class Constants { 111 Constants() { } // static only 112 113 static final int 114 MN_IS_METHOD = 0x00010000, // method (not constructor) 115 MN_IS_CONSTRUCTOR = 0x00020000, // constructor 116 MN_IS_FIELD = 0x00040000, // field 117 MN_IS_TYPE = 0x00080000, // nested type 118 MN_CALLER_SENSITIVE = 0x00100000, // @CallerSensitive annotation detected 119 MN_REFERENCE_KIND_SHIFT = 24, // refKind 120 MN_REFERENCE_KIND_MASK = 0x0F000000 >> MN_REFERENCE_KIND_SHIFT, 121 // The SEARCH_* bits are not for MN.flags but for the matchFlags argument of MHN.getMembers: 122 MN_SEARCH_SUPERCLASSES = 0x00100000, 123 MN_SEARCH_INTERFACES = 0x00200000; 124 125 /** 126 * Constant pool reference-kind codes, as used by CONSTANT_MethodHandle CP entries. 127 */ 128 static final byte 129 REF_NONE = 0, // null value 130 REF_getField = 1, 131 REF_getStatic = 2, 132 REF_putField = 3, 133 REF_putStatic = 4, 134 REF_invokeVirtual = 5, 135 REF_invokeStatic = 6, 136 REF_invokeSpecial = 7, 137 REF_newInvokeSpecial = 8, 138 REF_invokeInterface = 9, 139 REF_LIMIT = 10; 140 } 141 142 static boolean refKindIsValid(int refKind) { 143 return (refKind > REF_NONE && refKind < REF_LIMIT); 144 } 145 static boolean refKindIsField(byte refKind) { 146 assert(refKindIsValid(refKind)); 147 return (refKind <= REF_putStatic); 148 } 149 static boolean refKindIsGetter(byte refKind) { 150 assert(refKindIsValid(refKind)); 151 return (refKind <= REF_getStatic); 152 } 153 static boolean refKindIsSetter(byte refKind) { 154 return refKindIsField(refKind) && !refKindIsGetter(refKind); 155 } 156 static boolean refKindIsMethod(byte refKind) { 157 return !refKindIsField(refKind) && (refKind != REF_newInvokeSpecial); 158 } 159 static boolean refKindIsConstructor(byte refKind) { 160 return (refKind == REF_newInvokeSpecial); 161 } 162 static boolean refKindHasReceiver(byte refKind) { 163 assert(refKindIsValid(refKind)); 164 return (refKind & 1) != 0; 165 } 166 static boolean refKindIsStatic(byte refKind) { 167 return !refKindHasReceiver(refKind) && (refKind != REF_newInvokeSpecial); 168 } 169 static boolean refKindDoesDispatch(byte refKind) { 170 assert(refKindIsValid(refKind)); 171 return (refKind == REF_invokeVirtual || 172 refKind == REF_invokeInterface); 173 } 174 static { 175 final int HR_MASK = ((1 << REF_getField) | 176 (1 << REF_putField) | 177 (1 << REF_invokeVirtual) | 178 (1 << REF_invokeSpecial) | 179 (1 << REF_invokeInterface) 180 ); 181 for (byte refKind = REF_NONE+1; refKind < REF_LIMIT; refKind++) { 182 assert(refKindHasReceiver(refKind) == (((1<<refKind) & HR_MASK) != 0)) : refKind; 183 } 184 } 185 static String refKindName(byte refKind) { 186 assert(refKindIsValid(refKind)); 187 switch (refKind) { 188 case REF_getField: return "getField"; 189 case REF_getStatic: return "getStatic"; 190 case REF_putField: return "putField"; 191 case REF_putStatic: return "putStatic"; 192 case REF_invokeVirtual: return "invokeVirtual"; 193 case REF_invokeStatic: return "invokeStatic"; 194 case REF_invokeSpecial: return "invokeSpecial"; 195 case REF_newInvokeSpecial: return "newInvokeSpecial"; 196 case REF_invokeInterface: return "invokeInterface"; 197 default: return "REF_???"; 198 } 199 } 200 201 private static native int getNamedCon(int which, Object[] name); 202 static boolean verifyConstants() { 203 Object[] box = { null }; 204 for (int i = 0; ; i++) { 205 box[0] = null; 206 int vmval = getNamedCon(i, box); 207 if (box[0] == null) break; 208 String name = (String) box[0]; 209 try { 210 Field con = Constants.class.getDeclaredField(name); 211 int jval = con.getInt(null); 212 if (jval == vmval) continue; 213 String err = (name+": JVM has "+vmval+" while Java has "+jval); 214 if (name.equals("CONV_OP_LIMIT")) { 215 System.err.println("warning: "+err); 216 continue; 217 } 218 throw new InternalError(err); 219 } catch (NoSuchFieldException | IllegalAccessException ex) { 220 String err = (name+": JVM has "+vmval+" which Java does not define"); 221 // ignore exotic ops the JVM cares about; we just wont issue them 222 //System.err.println("warning: "+err); 223 continue; 224 } 225 } 226 return true; 227 } 228 static { 229 assert(verifyConstants()); 230 } 231 232 // Up-calls from the JVM. 233 // These must NOT be public. 234 235 /** 236 * The JVM is linking an invokedynamic instruction. Create a reified call site for it. 237 */ 238 static MemberName linkCallSite(Object callerObj, 239 int indexInCP, 240 Object bootstrapMethodObj, 241 Object nameObj, Object typeObj, 242 Object staticArguments, 243 Object[] appendixResult) { 244 MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj; 245 Class<?> caller = (Class<?>)callerObj; 246 String name = nameObj.toString().intern(); 247 MethodType type = (MethodType)typeObj; 248 if (!TRACE_METHOD_LINKAGE) 249 return linkCallSiteImpl(caller, bootstrapMethod, name, type, 250 staticArguments, appendixResult); 251 return linkCallSiteTracing(caller, bootstrapMethod, name, type, 252 staticArguments, appendixResult); 253 } 254 static MemberName linkCallSiteImpl(Class<?> caller, 255 MethodHandle bootstrapMethod, 256 String name, MethodType type, 257 Object staticArguments, 258 Object[] appendixResult) { 259 CallSite callSite = CallSite.makeSite(bootstrapMethod, 260 name, 261 type, 262 staticArguments, 263 caller); 264 if (callSite instanceof ConstantCallSite) { 265 appendixResult[0] = callSite.dynamicInvoker(); 266 return Invokers.linkToTargetMethod(type); 267 } else { 268 appendixResult[0] = callSite; 269 return Invokers.linkToCallSiteMethod(type); 270 } 271 } 272 // Tracing logic: 273 static MemberName linkCallSiteTracing(Class<?> caller, 274 MethodHandle bootstrapMethod, 275 String name, MethodType type, 276 Object staticArguments, 277 Object[] appendixResult) { 278 Object bsmReference = bootstrapMethod.internalMemberName(); 279 if (bsmReference == null) bsmReference = bootstrapMethod; 280 String staticArglist = staticArglistForTrace(staticArguments); 281 System.out.println("linkCallSite "+caller.getName()+" "+ 282 bsmReference+" "+ 283 name+type+"/"+staticArglist); 284 try { 285 MemberName res = linkCallSiteImpl(caller, bootstrapMethod, name, type, 286 staticArguments, appendixResult); 287 System.out.println("linkCallSite => "+res+" + "+appendixResult[0]); 288 return res; 289 } catch (Throwable ex) { 290 ex.printStackTrace(); // print now in case exception is swallowed 291 System.out.println("linkCallSite => throw "+ex); 292 throw ex; 293 } 294 } 295 296 // this implements the upcall from the JVM, MethodHandleNatives.linkDynamicConstant: 297 static Object linkDynamicConstant(Object callerObj, 298 int indexInCP, 299 Object bootstrapMethodObj, 300 Object nameObj, Object typeObj, 301 Object staticArguments) { 302 MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj; 303 Class<?> caller = (Class<?>)callerObj; 304 String name = nameObj.toString().intern(); 305 Class<?> type = (Class<?>)typeObj; 306 if (!TRACE_METHOD_LINKAGE) 307 return linkDynamicConstantImpl(caller, bootstrapMethod, name, type, staticArguments); 308 return linkDynamicConstantTracing(caller, bootstrapMethod, name, type, staticArguments); 309 } 310 311 static Object linkDynamicConstantImpl(Class<?> caller, 312 MethodHandle bootstrapMethod, 313 String name, Class<?> type, 314 Object staticArguments) { 315 return ConstantBootstraps.makeConstant(bootstrapMethod, name, type, staticArguments, caller); 316 } 317 318 private static String staticArglistForTrace(Object staticArguments) { 319 if (staticArguments instanceof Object[]) 320 return "BSA="+java.util.Arrays.asList((Object[]) staticArguments); 321 if (staticArguments instanceof int[]) 322 return "BSA@"+java.util.Arrays.toString((int[]) staticArguments); 323 if (staticArguments == null) 324 return "BSA0=null"; 325 return "BSA1="+staticArguments; 326 } 327 328 // Tracing logic: 329 static Object linkDynamicConstantTracing(Class<?> caller, 330 MethodHandle bootstrapMethod, 331 String name, Class<?> type, 332 Object staticArguments) { 333 Object bsmReference = bootstrapMethod.internalMemberName(); 334 if (bsmReference == null) bsmReference = bootstrapMethod; 335 String staticArglist = staticArglistForTrace(staticArguments); 336 System.out.println("linkDynamicConstant "+caller.getName()+" "+ 337 bsmReference+" "+ 338 name+type+"/"+staticArglist); 339 try { 340 Object res = linkDynamicConstantImpl(caller, bootstrapMethod, name, type, staticArguments); 341 System.out.println("linkDynamicConstantImpl => "+res); 342 return res; 343 } catch (Throwable ex) { 344 ex.printStackTrace(); // print now in case exception is swallowed 345 System.out.println("linkDynamicConstant => throw "+ex); 346 throw ex; 347 } 348 } 349 350 /** The JVM is requesting pull-mode bootstrap when it provides 351 * a tuple of the form int[]{ argc, vmindex }. 352 * The BSM is expected to call back to the JVM using the caller 353 * class and vmindex to resolve the static arguments. 354 */ 355 static boolean staticArgumentsPulled(Object staticArguments) { 356 return staticArguments instanceof int[]; 357 } 358 359 /** A BSM runs in pull-mode if and only if its sole arguments 360 * are (Lookup, BootstrapCallInfo), or can be converted pairwise 361 * to those types, and it is not of variable arity. 362 * Excluding error cases, we can just test that the arity is a constant 2. 363 * 364 * NOTE: This method currently returns false, since pulling is not currently 365 * exposed to a BSM. When pull mode is supported the method block will be 366 * replaced with currently commented out code. 367 */ 368 static boolean isPullModeBSM(MethodHandle bsm) { 369 return false; 370 // return bsm.type().parameterCount() == 2 && !bsm.isVarargsCollector(); 371 } 372 373 /** 374 * The JVM wants a pointer to a MethodType. Oblige it by finding or creating one. 375 */ 376 static MethodType findMethodHandleType(Class<?> rtype, Class<?>[] ptypes) { 377 return MethodType.makeImpl(rtype, ptypes, true); 378 } 379 380 /** 381 * The JVM wants to link a call site that requires a dynamic type check. 382 * Name is a type-checking invoker, invokeExact or invoke. 383 * Return a JVM method (MemberName) to handle the invoking. 384 * The method assumes the following arguments on the stack: 385 * 0: the method handle being invoked 386 * 1-N: the arguments to the method handle invocation 387 * N+1: an optional, implicitly added argument (typically the given MethodType) 388 * <p> 389 * The nominal method at such a call site is an instance of 390 * a signature-polymorphic method (see @PolymorphicSignature). 391 * Such method instances are user-visible entities which are 392 * "split" from the generic placeholder method in {@code MethodHandle}. 393 * (Note that the placeholder method is not identical with any of 394 * its instances. If invoked reflectively, is guaranteed to throw an 395 * {@code UnsupportedOperationException}.) 396 * If the signature-polymorphic method instance is ever reified, 397 * it appears as a "copy" of the original placeholder 398 * (a native final member of {@code MethodHandle}) except 399 * that its type descriptor has shape required by the instance, 400 * and the method instance is <em>not</em> varargs. 401 * The method instance is also marked synthetic, since the 402 * method (by definition) does not appear in Java source code. 403 * <p> 404 * The JVM is allowed to reify this method as instance metadata. 405 * For example, {@code invokeBasic} is always reified. 406 * But the JVM may instead call {@code linkMethod}. 407 * If the result is an * ordered pair of a {@code (method, appendix)}, 408 * the method gets all the arguments (0..N inclusive) 409 * plus the appendix (N+1), and uses the appendix to complete the call. 410 * In this way, one reusable method (called a "linker method") 411 * can perform the function of any number of polymorphic instance 412 * methods. 413 * <p> 414 * Linker methods are allowed to be weakly typed, with any or 415 * all references rewritten to {@code Object} and any primitives 416 * (except {@code long}/{@code float}/{@code double}) 417 * rewritten to {@code int}. 418 * A linker method is trusted to return a strongly typed result, 419 * according to the specific method type descriptor of the 420 * signature-polymorphic instance it is emulating. 421 * This can involve (as necessary) a dynamic check using 422 * data extracted from the appendix argument. 423 * <p> 424 * The JVM does not inspect the appendix, other than to pass 425 * it verbatim to the linker method at every call. 426 * This means that the JDK runtime has wide latitude 427 * for choosing the shape of each linker method and its 428 * corresponding appendix. 429 * Linker methods should be generated from {@code LambdaForm}s 430 * so that they do not become visible on stack traces. 431 * <p> 432 * The {@code linkMethod} call is free to omit the appendix 433 * (returning null) and instead emulate the required function 434 * completely in the linker method. 435 * As a corner case, if N==255, no appendix is possible. 436 * In this case, the method returned must be custom-generated to 437 * perform any needed type checking. 438 * <p> 439 * If the JVM does not reify a method at a call site, but instead 440 * calls {@code linkMethod}, the corresponding call represented 441 * in the bytecodes may mention a valid method which is not 442 * representable with a {@code MemberName}. 443 * Therefore, use cases for {@code linkMethod} tend to correspond to 444 * special cases in reflective code such as {@code findVirtual} 445 * or {@code revealDirect}. 446 */ 447 static MemberName linkMethod(Class<?> callerClass, int refKind, 448 Class<?> defc, String name, Object type, 449 Object[] appendixResult) { 450 if (!TRACE_METHOD_LINKAGE) 451 return linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult); 452 return linkMethodTracing(callerClass, refKind, defc, name, type, appendixResult); 453 } 454 static MemberName linkMethodImpl(Class<?> callerClass, int refKind, 455 Class<?> defc, String name, Object type, 456 Object[] appendixResult) { 457 try { 458 if (refKind == REF_invokeVirtual) { 459 if (defc == MethodHandle.class) { 460 return Invokers.methodHandleInvokeLinkerMethod( 461 name, fixMethodType(callerClass, type), appendixResult); 462 } else if (defc == VarHandle.class) { 463 return varHandleOperationLinkerMethod( 464 name, fixMethodType(callerClass, type), appendixResult); 465 } 466 } 467 } catch (Error e) { 468 // Pass through an Error, including say StackOverflowError or 469 // OutOfMemoryError 470 throw e; 471 } catch (Throwable ex) { 472 // Wrap anything else in LinkageError 473 throw new LinkageError(ex.getMessage(), ex); 474 } 475 throw new LinkageError("no such method "+defc.getName()+"."+name+type); 476 } 477 private static MethodType fixMethodType(Class<?> callerClass, Object type) { 478 if (type instanceof MethodType) 479 return (MethodType) type; 480 else 481 return MethodType.fromDescriptor((String)type, callerClass.getClassLoader()); 482 } 483 // Tracing logic: 484 static MemberName linkMethodTracing(Class<?> callerClass, int refKind, 485 Class<?> defc, String name, Object type, 486 Object[] appendixResult) { 487 System.out.println("linkMethod "+defc.getName()+"."+ 488 name+type+"/"+Integer.toHexString(refKind)); 489 try { 490 MemberName res = linkMethodImpl(callerClass, refKind, defc, name, type, appendixResult); 491 System.out.println("linkMethod => "+res+" + "+appendixResult[0]); 492 return res; 493 } catch (Throwable ex) { 494 System.out.println("linkMethod => throw "+ex); 495 throw ex; 496 } 497 } 498 499 /** 500 * Obtain the method to link to the VarHandle operation. 501 * This method is located here and not in Invokers to avoid 502 * intializing that and other classes early on in VM bootup. 503 */ 504 private static MemberName varHandleOperationLinkerMethod(String name, 505 MethodType mtype, 506 Object[] appendixResult) { 507 // Get the signature method type 508 final MethodType sigType = mtype.basicType(); 509 510 // Get the access kind from the method name 511 VarHandle.AccessMode ak; 512 try { 513 ak = VarHandle.AccessMode.valueFromMethodName(name); 514 } catch (IllegalArgumentException e) { 515 throw MethodHandleStatics.newInternalError(e); 516 } 517 518 // Create the appendix descriptor constant 519 VarHandle.AccessDescriptor ad = new VarHandle.AccessDescriptor(mtype, ak.at.ordinal(), ak.ordinal()); 520 appendixResult[0] = ad; 521 522 if (MethodHandleStatics.VAR_HANDLE_GUARDS) { 523 // If not polymorphic in the return type, such as the compareAndSet 524 // methods that return boolean 525 Class<?> guardReturnType = sigType.returnType(); 526 if (ak.at.isMonomorphicInReturnType) { 527 if (ak.at.returnType != mtype.returnType()) { 528 // The caller contains a different return type than that 529 // defined by the method 530 throw newNoSuchMethodErrorOnVarHandle(name, mtype); 531 } 532 // Adjust the return type of the signature method type 533 guardReturnType = ak.at.returnType; 534 } 535 536 // Get the guard method type for linking 537 final Class<?>[] guardParams = new Class<?>[sigType.parameterCount() + 2]; 538 // VarHandle at start 539 guardParams[0] = VarHandle.class; 540 for (int i = 0; i < sigType.parameterCount(); i++) { 541 guardParams[i + 1] = sigType.parameterType(i); 542 } 543 // Access descriptor at end 544 guardParams[guardParams.length - 1] = VarHandle.AccessDescriptor.class; 545 MethodType guardType = MethodType.makeImpl(guardReturnType, guardParams, true); 546 547 MemberName linker = new MemberName( 548 VarHandleGuards.class, getVarHandleGuardMethodName(guardType), 549 guardType, REF_invokeStatic); 550 551 linker = MemberName.getFactory().resolveOrNull(REF_invokeStatic, linker, 552 VarHandleGuards.class); 553 if (linker != null) { 554 return linker; 555 } 556 // Fall back to lambda form linkage if guard method is not available 557 // TODO Optionally log fallback ? 558 } 559 return Invokers.varHandleInvokeLinkerMethod(ak, mtype); 560 } 561 static String getVarHandleGuardMethodName(MethodType guardType) { 562 String prefix = "guard_"; 563 StringBuilder sb = new StringBuilder(prefix.length() + guardType.parameterCount()); 564 565 sb.append(prefix); 566 for (int i = 1; i < guardType.parameterCount() - 1; i++) { 567 Class<?> pt = guardType.parameterType(i); 568 sb.append(getCharType(pt)); 569 } 570 sb.append('_').append(getCharType(guardType.returnType())); 571 return sb.toString(); 572 } 573 static char getCharType(Class<?> pt) { 574 return Wrapper.forBasicType(pt).basicTypeChar(); 575 } 576 static NoSuchMethodError newNoSuchMethodErrorOnVarHandle(String name, MethodType mtype) { 577 return new NoSuchMethodError("VarHandle." + name + mtype); 578 } 579 580 /** 581 * The JVM is resolving a CONSTANT_MethodHandle CP entry. And it wants our help. 582 * It will make an up-call to this method. (Do not change the name or signature.) 583 * The type argument is a Class for field requests and a MethodType for non-fields. 584 * <p> 585 * Recent versions of the JVM may also pass a resolved MemberName for the type. 586 * In that case, the name is ignored and may be null. 587 */ 588 static MethodHandle linkMethodHandleConstant(Class<?> callerClass, int refKind, 589 Class<?> defc, String name, Object type) { 590 try { 591 Lookup lookup = IMPL_LOOKUP.in(callerClass); 592 assert(refKindIsValid(refKind)); 593 return lookup.linkMethodHandleConstant((byte) refKind, defc, name, type); 594 } catch (ReflectiveOperationException ex) { 595 throw mapLookupExceptionToError(ex); 596 } 597 } 598 599 /** 600 * Map a reflective exception to a linkage error. 601 */ 602 static LinkageError mapLookupExceptionToError(ReflectiveOperationException ex) { 603 LinkageError err; 604 if (ex instanceof IllegalAccessException) { 605 Throwable cause = ex.getCause(); 606 if (cause instanceof AbstractMethodError) { 607 return (AbstractMethodError) cause; 608 } else { 609 err = new IllegalAccessError(ex.getMessage()); 610 } 611 } else if (ex instanceof NoSuchMethodException) { 612 err = new NoSuchMethodError(ex.getMessage()); 613 } else if (ex instanceof NoSuchFieldException) { 614 err = new NoSuchFieldError(ex.getMessage()); 615 } else { 616 err = new IncompatibleClassChangeError(); 617 } 618 return initCauseFrom(err, ex); 619 } 620 621 /** 622 * Use best possible cause for err.initCause(), substituting the 623 * cause for err itself if the cause has the same (or better) type. 624 */ 625 static <E extends Error> E initCauseFrom(E err, Exception ex) { 626 Throwable th = ex.getCause(); 627 @SuppressWarnings("unchecked") 628 final Class<E> Eclass = (Class<E>) err.getClass(); 629 if (Eclass.isInstance(th)) 630 return Eclass.cast(th); 631 err.initCause(th == null ? ex : th); 632 return err; 633 } 634 635 /** 636 * Is this method a caller-sensitive method? 637 * I.e., does it call Reflection.getCallerClass or a similar method 638 * to ask about the identity of its caller? 639 */ 640 static boolean isCallerSensitive(MemberName mem) { 641 if (!mem.isInvocable()) return false; // fields are not caller sensitive 642 643 return mem.isCallerSensitive() || canBeCalledVirtual(mem); 644 } 645 646 static boolean canBeCalledVirtual(MemberName mem) { 647 assert(mem.isInvocable()); 648 switch (mem.getName()) { 649 case "getContextClassLoader": 650 return canBeCalledVirtual(mem, java.lang.Thread.class); 651 } 652 return false; 653 } 654 655 static boolean canBeCalledVirtual(MemberName symbolicRef, Class<?> definingClass) { 656 Class<?> symbolicRefClass = symbolicRef.getDeclaringClass(); 657 if (symbolicRefClass == definingClass) return true; 658 if (symbolicRef.isStatic() || symbolicRef.isPrivate()) return false; 659 return (definingClass.isAssignableFrom(symbolicRefClass) || // Msym overrides Mdef 660 symbolicRefClass.isInterface()); // Mdef implements Msym 661 } 662 }