Bootstrap.java revision 1163:d4510be6f97a
1/* 2 * Copyright (c) 2010, 2013, 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 26package jdk.nashorn.internal.runtime.linker; 27 28import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup; 29import static jdk.nashorn.internal.runtime.ECMAErrors.typeError; 30 31import java.lang.invoke.CallSite; 32import java.lang.invoke.ConstantCallSite; 33import java.lang.invoke.MethodHandle; 34import java.lang.invoke.MethodHandles; 35import java.lang.invoke.MethodHandles.Lookup; 36import java.lang.invoke.MethodType; 37import jdk.internal.dynalink.CallSiteDescriptor; 38import jdk.internal.dynalink.DynamicLinker; 39import jdk.internal.dynalink.DynamicLinkerFactory; 40import jdk.internal.dynalink.GuardedInvocationFilter; 41import jdk.internal.dynalink.beans.BeansLinker; 42import jdk.internal.dynalink.beans.StaticClass; 43import jdk.internal.dynalink.linker.GuardedInvocation; 44import jdk.internal.dynalink.linker.LinkRequest; 45import jdk.internal.dynalink.linker.LinkerServices; 46import jdk.internal.dynalink.linker.MethodTypeConversionStrategy; 47import jdk.internal.dynalink.support.TypeUtilities; 48import jdk.nashorn.api.scripting.JSObject; 49import jdk.nashorn.internal.codegen.CompilerConstants.Call; 50import jdk.nashorn.internal.codegen.ObjectClassGenerator; 51import jdk.nashorn.internal.codegen.RuntimeCallSite; 52import jdk.nashorn.internal.lookup.MethodHandleFactory; 53import jdk.nashorn.internal.lookup.MethodHandleFunctionality; 54import jdk.nashorn.internal.objects.ScriptFunctionImpl; 55import jdk.nashorn.internal.runtime.ECMAException; 56import jdk.nashorn.internal.runtime.JSType; 57import jdk.nashorn.internal.runtime.OptimisticReturnFilters; 58import jdk.nashorn.internal.runtime.ScriptFunction; 59import jdk.nashorn.internal.runtime.ScriptRuntime; 60import jdk.nashorn.internal.runtime.options.Options; 61 62/** 63 * This class houses bootstrap method for invokedynamic instructions generated by compiler. 64 */ 65public final class Bootstrap { 66 /** Reference to the seed boostrap function */ 67 public static final Call BOOTSTRAP = staticCallNoLookup(Bootstrap.class, "bootstrap", CallSite.class, Lookup.class, String.class, MethodType.class, int.class); 68 69 private static final MethodHandleFunctionality MH = MethodHandleFactory.getFunctionality(); 70 71 private static final MethodHandle VOID_TO_OBJECT = MH.constant(Object.class, ScriptRuntime.UNDEFINED); 72 73 /** 74 * The default dynalink relink threshold for megamorphisism is 8. In the case 75 * of object fields only, it is fine. However, with dual fields, in order to get 76 * performance on benchmarks with a lot of object instantiation and then field 77 * reassignment, it can take slightly more relinks to become stable with type 78 * changes swapping out an entire proprety map and making a map guard fail. 79 * Therefore the relink threshold is set to 16 for dual fields (now the default). 80 * This doesn't seem to have any other negative performance implication. 81 * 82 * See for example octane.gbemu, run with --log=fields:warning to study 83 * megamorphic behavior 84 */ 85 private static final int NASHORN_DEFAULT_UNSTABLE_RELINK_THRESHOLD = 86 ObjectClassGenerator.OBJECT_FIELDS_ONLY ? 87 8 : 88 16; 89 90 // do not create me!! 91 private Bootstrap() { 92 } 93 94 private static final DynamicLinker dynamicLinker; 95 static { 96 final DynamicLinkerFactory factory = new DynamicLinkerFactory(); 97 final NashornBeansLinker nashornBeansLinker = new NashornBeansLinker(); 98 factory.setPrioritizedLinkers( 99 new NashornLinker(), 100 new NashornPrimitiveLinker(), 101 new NashornStaticClassLinker(), 102 new BoundCallableLinker(), 103 new JavaSuperAdapterLinker(), 104 new JSObjectLinker(nashornBeansLinker), 105 new BrowserJSObjectLinker(nashornBeansLinker), 106 new ReflectionCheckLinker()); 107 factory.setFallbackLinkers(nashornBeansLinker, new NashornBottomLinker()); 108 factory.setSyncOnRelink(true); 109 factory.setPrelinkFilter(new GuardedInvocationFilter() { 110 @Override 111 public GuardedInvocation filter(final GuardedInvocation inv, final LinkRequest request, final LinkerServices linkerServices) { 112 final CallSiteDescriptor desc = request.getCallSiteDescriptor(); 113 return OptimisticReturnFilters.filterOptimisticReturnValue(inv, desc).asType(linkerServices, desc.getMethodType()); 114 } 115 }); 116 factory.setAutoConversionStrategy(new MethodTypeConversionStrategy() { 117 @Override 118 public MethodHandle asType(final MethodHandle target, final MethodType newType) { 119 return unboxReturnType(target, newType); 120 } 121 }); 122 final int relinkThreshold = Options.getIntProperty("nashorn.unstable.relink.threshold", NASHORN_DEFAULT_UNSTABLE_RELINK_THRESHOLD); 123 if (relinkThreshold > -1) { 124 factory.setUnstableRelinkThreshold(relinkThreshold); 125 } 126 127 // Linkers for any additional language runtimes deployed alongside Nashorn will be picked up by the factory. 128 factory.setClassLoader(Bootstrap.class.getClassLoader()); 129 130 dynamicLinker = factory.createLinker(); 131 } 132 133 /** 134 * Returns if the given object is a "callable" 135 * @param obj object to be checked for callability 136 * @return true if the obj is callable 137 */ 138 public static boolean isCallable(final Object obj) { 139 if (obj == ScriptRuntime.UNDEFINED || obj == null) { 140 return false; 141 } 142 143 return obj instanceof ScriptFunction || 144 isJSObjectFunction(obj) || 145 BeansLinker.isDynamicMethod(obj) || 146 obj instanceof BoundCallable || 147 isFunctionalInterfaceObject(obj) || 148 obj instanceof StaticClass; 149 } 150 151 /** 152 * Returns true if the given object is a strict callable 153 * @param callable the callable object to be checked for strictness 154 * @return true if the obj is a strict callable, false if it is a non-strict callable. 155 * @throws ECMAException with {@code TypeError} if the object is not a callable. 156 */ 157 public static boolean isStrictCallable(final Object callable) { 158 if (callable instanceof ScriptFunction) { 159 return ((ScriptFunction)callable).isStrict(); 160 } else if (isJSObjectFunction(callable)) { 161 return ((JSObject)callable).isStrictFunction(); 162 } else if (callable instanceof BoundCallable) { 163 return isStrictCallable(((BoundCallable)callable).getCallable()); 164 } else if (BeansLinker.isDynamicMethod(callable) || callable instanceof StaticClass) { 165 return false; 166 } 167 throw notFunction(callable); 168 } 169 170 private static ECMAException notFunction(final Object obj) { 171 return typeError("not.a.function", ScriptRuntime.safeToString(obj)); 172 } 173 174 private static boolean isJSObjectFunction(final Object obj) { 175 return obj instanceof JSObject && ((JSObject)obj).isFunction(); 176 } 177 178 /** 179 * Returns if the given object is a dynalink Dynamic method 180 * @param obj object to be checked 181 * @return true if the obj is a dynamic method 182 */ 183 public static boolean isDynamicMethod(final Object obj) { 184 return BeansLinker.isDynamicMethod(obj instanceof BoundCallable ? ((BoundCallable)obj).getCallable() : obj); 185 } 186 187 /** 188 * Returns if the given object is an instance of an interface annotated with 189 * java.lang.FunctionalInterface 190 * @param obj object to be checked 191 * @return true if the obj is an instance of @FunctionalInterface interface 192 */ 193 public static boolean isFunctionalInterfaceObject(final Object obj) { 194 return !JSType.isPrimitive(obj) && (NashornBeansLinker.getFunctionalInterfaceMethod(obj.getClass()) != null); 195 } 196 197 /** 198 * Create a call site and link it for Nashorn. This version of the method conforms to the invokedynamic bootstrap 199 * method expected signature and is referenced from Nashorn generated bytecode as the bootstrap method for all 200 * invokedynamic instructions. 201 * @param lookup MethodHandle lookup. Ignored as Nashorn only uses public lookup. 202 * @param opDesc Dynalink dynamic operation descriptor. 203 * @param type Method type. 204 * @param flags flags for call type, trace/profile etc. 205 * @return CallSite with MethodHandle to appropriate method or null if not found. 206 */ 207 public static CallSite bootstrap(final Lookup lookup, final String opDesc, final MethodType type, final int flags) { 208 return dynamicLinker.link(LinkerCallSite.newLinkerCallSite(lookup, opDesc, type, flags)); 209 } 210 211 /** 212 * Bootstrapper for a specialized Runtime call 213 * 214 * @param lookup lookup 215 * @param initialName initial name for callsite 216 * @param type method type for call site 217 * 218 * @return callsite for a runtime node 219 */ 220 public static CallSite runtimeBootstrap(final MethodHandles.Lookup lookup, final String initialName, final MethodType type) { 221 return new RuntimeCallSite(type, initialName); 222 } 223 224 /** 225 * Boostrapper for math calls that may overflow 226 * @param lookup lookup 227 * @param name name of operation 228 * @param type method type 229 * @param programPoint program point to bind to callsite 230 * 231 * @return callsite for a math instrinic node 232 */ 233 public static CallSite mathBootstrap(final MethodHandles.Lookup lookup, final String name, final MethodType type, final int programPoint) { 234 final MethodHandle mh; 235 switch (name) { 236 case "iadd": 237 mh = JSType.ADD_EXACT.methodHandle(); 238 break; 239 case "isub": 240 mh = JSType.SUB_EXACT.methodHandle(); 241 break; 242 case "imul": 243 mh = JSType.MUL_EXACT.methodHandle(); 244 break; 245 case "idiv": 246 mh = JSType.DIV_EXACT.methodHandle(); 247 break; 248 case "irem": 249 mh = JSType.REM_EXACT.methodHandle(); 250 break; 251 case "ineg": 252 mh = JSType.NEGATE_EXACT.methodHandle(); 253 break; 254 case "ladd": 255 mh = JSType.ADD_EXACT_LONG.methodHandle(); 256 break; 257 case "lsub": 258 mh = JSType.SUB_EXACT_LONG.methodHandle(); 259 break; 260 case "lmul": 261 mh = JSType.MUL_EXACT_LONG.methodHandle(); 262 break; 263 case "ldiv": 264 mh = JSType.DIV_EXACT_LONG.methodHandle(); 265 break; 266 case "lrem": 267 mh = JSType.REM_EXACT_LONG.methodHandle(); 268 break; 269 case "lneg": 270 mh = JSType.NEGATE_EXACT_LONG.methodHandle(); 271 break; 272 default: 273 throw new AssertionError("unsupported math intrinsic"); 274 } 275 return new ConstantCallSite(MH.insertArguments(mh, mh.type().parameterCount() - 1, programPoint)); 276 } 277 278 /** 279 * Returns a dynamic invoker for a specified dynamic operation using the public lookup. You can use this method to 280 * create a method handle that when invoked acts completely as if it were a Nashorn-linked call site. An overview of 281 * available dynamic operations can be found in the 282 * <a href="https://github.com/szegedi/dynalink/wiki/User-Guide-0.6">Dynalink User Guide</a>, but we'll show few 283 * examples here: 284 * <ul> 285 * <li>Get a named property with fixed name: 286 * <pre> 287 * MethodHandle getColor = Boostrap.createDynamicInvoker("dyn:getProp:color", Object.class, Object.class); 288 * Object obj = ...; // somehow obtain the object 289 * Object color = getColor.invokeExact(obj); 290 * </pre> 291 * </li> 292 * <li>Get a named property with variable name: 293 * <pre> 294 * MethodHandle getProperty = Boostrap.createDynamicInvoker("dyn:getElem", Object.class, Object.class, String.class); 295 * Object obj = ...; // somehow obtain the object 296 * Object color = getProperty.invokeExact(obj, "color"); 297 * Object shape = getProperty.invokeExact(obj, "shape"); 298 * MethodHandle getNumProperty = Boostrap.createDynamicInvoker("dyn:getElem", Object.class, Object.class, int.class); 299 * Object elem42 = getNumProperty.invokeExact(obj, 42); 300 * </pre> 301 * </li> 302 * <li>Set a named property with fixed name: 303 * <pre> 304 * MethodHandle setColor = Boostrap.createDynamicInvoker("dyn:setProp:color", void.class, Object.class, Object.class); 305 * Object obj = ...; // somehow obtain the object 306 * setColor.invokeExact(obj, Color.BLUE); 307 * </pre> 308 * </li> 309 * <li>Set a property with variable name: 310 * <pre> 311 * MethodHandle setProperty = Boostrap.createDynamicInvoker("dyn:setElem", void.class, Object.class, String.class, Object.class); 312 * Object obj = ...; // somehow obtain the object 313 * setProperty.invokeExact(obj, "color", Color.BLUE); 314 * setProperty.invokeExact(obj, "shape", Shape.CIRCLE); 315 * </pre> 316 * </li> 317 * <li>Call a function on an object; two-step variant. This is the actual variant used by Nashorn-generated code: 318 * <pre> 319 * MethodHandle findFooFunction = Boostrap.createDynamicInvoker("dyn:getMethod:foo", Object.class, Object.class); 320 * Object obj = ...; // somehow obtain the object 321 * Object foo_fn = findFooFunction.invokeExact(obj); 322 * MethodHandle callFunctionWithTwoArgs = Boostrap.createDynamicInvoker("dyn:call", Object.class, Object.class, Object.class, Object.class, Object.class); 323 * // Note: "call" operation takes a function, then a "this" value, then the arguments: 324 * Object foo_retval = callFunctionWithTwoArgs.invokeExact(foo_fn, obj, arg1, arg2); 325 * </pre> 326 * </li> 327 * <li>Call a function on an object; single-step variant. Although Nashorn doesn't use this variant and never 328 * emits any INVOKEDYNAMIC instructions with {@code dyn:getMethod}, it still supports this standard Dynalink 329 * operation: 330 * <pre> 331 * MethodHandle callFunctionFooWithTwoArgs = Boostrap.createDynamicInvoker("dyn:callMethod:foo", Object.class, Object.class, Object.class, Object.class); 332 * Object obj = ...; // somehow obtain the object 333 * Object foo_retval = callFunctionFooWithTwoArgs.invokeExact(obj, arg1, arg2); 334 * </pre> 335 * </li> 336 * </ul> 337 * Few additional remarks: 338 * <ul> 339 * <li>Just as Nashorn works with any Java object, the invokers returned from this method can also be applied to 340 * arbitrary Java objects in addition to Nashorn JavaScript objects.</li> 341 * <li>For invoking a named function on an object, you can also use the {@link InvokeByName} convenience class.</li> 342 * <li>For Nashorn objects {@code getElem}, {@code getProp}, and {@code getMethod} are handled almost identically, 343 * since JavaScript doesn't distinguish between different kinds of properties on an object. Either can be used with 344 * fixed property name or a variable property name. The only significant difference is handling of missing 345 * properties: {@code getMethod} for a missing member will link to a potential invocation of 346 * {@code __noSuchMethod__} on the object, {@code getProp} for a missing member will link to a potential invocation 347 * of {@code __noSuchProperty__}, while {@code getElem} for a missing member will link to an empty getter.</li> 348 * <li>In similar vein, {@code setElem} and {@code setProp} are handled identically on Nashorn objects.</li> 349 * <li>There's no rule that the variable property identifier has to be a {@code String} for {@code getProp/setProp} 350 * and {@code int} for {@code getElem/setElem}. You can declare their type to be {@code int}, {@code double}, 351 * {@code Object}, and so on regardless of the kind of the operation.</li> 352 * <li>You can be as specific in parameter types as you want. E.g. if you know that the receiver of the operation 353 * will always be {@code ScriptObject}, you can pass {@code ScriptObject.class} as its parameter type. If you happen 354 * to link to a method that expects different types, (you can use these invokers on POJOs too, after all, and end up 355 * linking with their methods that have strongly-typed signatures), all necessary conversions allowed by either Java 356 * or JavaScript will be applied: if invoked methods specify either primitive or wrapped Java numeric types, or 357 * {@code String} or {@code boolean/Boolean}, then the parameters might be subjected to standard ECMAScript 358 * {@code ToNumber}, {@code ToString}, and {@code ToBoolean} conversion, respectively. Less obviously, if the 359 * expected parameter type is a SAM type, and you pass a JavaScript function, a proxy object implementing the SAM 360 * type and delegating to the function will be passed. Linkage can often be optimized when linkers have more 361 * specific type information than "everything can be an object".</li> 362 * <li>You can also be as specific in return types as you want. For return types any necessary type conversion 363 * available in either Java or JavaScript will be automatically applied, similar to the process described for 364 * parameters, only in reverse direction: if you specify any either primitive or wrapped Java numeric type, or 365 * {@code String} or {@code boolean/Boolean}, then the return values will be subjected to standard ECMAScript 366 * {@code ToNumber}, {@code ToString}, and {@code ToBoolean} conversion, respectively. Less obviously, if the return 367 * type is a SAM type, and the return value is a JavaScript function, a proxy object implementing the SAM type and 368 * delegating to the function will be returned.</li> 369 * </ul> 370 * @param opDesc Dynalink dynamic operation descriptor. 371 * @param rtype the return type for the operation 372 * @param ptypes the parameter types for the operation 373 * @return MethodHandle for invoking the operation. 374 */ 375 public static MethodHandle createDynamicInvoker(final String opDesc, final Class<?> rtype, final Class<?>... ptypes) { 376 return createDynamicInvoker(opDesc, MethodType.methodType(rtype, ptypes)); 377 } 378 379 /** 380 * Returns a dynamic invoker for a specified dynamic operation using the public lookup. Similar to 381 * {@link #createDynamicInvoker(String, Class, Class...)} but with an additional parameter to 382 * set the call site flags of the dynamic invoker. 383 * @param opDesc Dynalink dynamic operation descriptor. 384 * @param flags the call site flags for the operation 385 * @param rtype the return type for the operation 386 * @param ptypes the parameter types for the operation 387 * @return MethodHandle for invoking the operation. 388 */ 389 public static MethodHandle createDynamicInvoker(final String opDesc, final int flags, final Class<?> rtype, final Class<?>... ptypes) { 390 return bootstrap(MethodHandles.publicLookup(), opDesc, MethodType.methodType(rtype, ptypes), flags).dynamicInvoker(); 391 } 392 393 /** 394 * Returns a dynamic invoker for a specified dynamic operation using the public lookup. Similar to 395 * {@link #createDynamicInvoker(String, Class, Class...)} but with return and parameter types composed into a 396 * method type in the signature. See the discussion of that method for details. 397 * @param opDesc Dynalink dynamic operation descriptor. 398 * @param type the method type for the operation 399 * @return MethodHandle for invoking the operation. 400 */ 401 public static MethodHandle createDynamicInvoker(final String opDesc, final MethodType type) { 402 return bootstrap(MethodHandles.publicLookup(), opDesc, type, 0).dynamicInvoker(); 403 } 404 405 /** 406 * Binds any object Nashorn can use as a [[Callable]] to a receiver and optionally arguments. 407 * @param callable the callable to bind 408 * @param boundThis the bound "this" value. 409 * @param boundArgs the bound arguments. Can be either null or empty array to signify no arguments are bound. 410 * @return a bound callable. 411 * @throws ECMAException with {@code TypeError} if the object is not a callable. 412 */ 413 public static Object bindCallable(final Object callable, final Object boundThis, final Object[] boundArgs) { 414 if (callable instanceof ScriptFunctionImpl) { 415 return ((ScriptFunctionImpl)callable).makeBoundFunction(boundThis, boundArgs); 416 } else if (callable instanceof BoundCallable) { 417 return ((BoundCallable)callable).bind(boundArgs); 418 } else if (isCallable(callable)) { 419 return new BoundCallable(callable, boundThis, boundArgs); 420 } 421 throw notFunction(callable); 422 } 423 424 /** 425 * Creates a super-adapter for an adapter, that is, an adapter to the adapter that allows invocation of superclass 426 * methods on it. 427 * @param adapter the original adapter 428 * @return a new adapter that can be used to invoke super methods on the original adapter. 429 */ 430 public static Object createSuperAdapter(final Object adapter) { 431 return new JavaSuperAdapter(adapter); 432 } 433 434 /** 435 * If the given class is a reflection-specific class (anything in {@code java.lang.reflect} and 436 * {@code java.lang.invoke} package, as well a {@link Class} and any subclass of {@link ClassLoader}) and there is 437 * a security manager in the system, then it checks the {@code nashorn.JavaReflection} {@code RuntimePermission}. 438 * @param clazz the class being tested 439 * @param isStatic is access checked for static members (or instance members) 440 */ 441 public static void checkReflectionAccess(final Class<?> clazz, final boolean isStatic) { 442 ReflectionCheckLinker.checkReflectionAccess(clazz, isStatic); 443 } 444 445 /** 446 * Returns the Nashorn's internally used dynamic linker's services object. Note that in code that is processing a 447 * linking request, you will normally use the {@code LinkerServices} object passed by whatever top-level linker 448 * invoked the linking (if the call site is in Nashorn-generated code, you'll get this object anyway). You should 449 * only resort to retrieving a linker services object using this method when you need some linker services (e.g. 450 * type converter method handles) outside of a code path that is linking a call site. 451 * @return Nashorn's internal dynamic linker's services object. 452 */ 453 public static LinkerServices getLinkerServices() { 454 return dynamicLinker.getLinkerServices(); 455 } 456 457 /** 458 * Takes a guarded invocation, and ensures its method and guard conform to the type of the call descriptor, using 459 * all type conversions allowed by the linker's services. This method is used by Nashorn's linkers as a last step 460 * before returning guarded invocations. Most of the code used to produce the guarded invocations does not make an 461 * effort to coordinate types of the methods, and so a final type adjustment before a guarded invocation is returned 462 * to the aggregating linker is the responsibility of the linkers themselves. 463 * @param inv the guarded invocation that needs to be type-converted. Can be null. 464 * @param linkerServices the linker services object providing the type conversions. 465 * @param desc the call site descriptor to whose method type the invocation needs to conform. 466 * @return the type-converted guarded invocation. If input is null, null is returned. If the input invocation 467 * already conforms to the requested type, it is returned unchanged. 468 */ 469 static GuardedInvocation asTypeSafeReturn(final GuardedInvocation inv, final LinkerServices linkerServices, final CallSiteDescriptor desc) { 470 return inv == null ? null : inv.asTypeSafeReturn(linkerServices, desc.getMethodType()); 471 } 472 473 /** 474 * Adapts the return type of the method handle with {@code explicitCastArguments} when it is an unboxing 475 * conversion. This will ensure that nulls are unwrapped to false or 0. 476 * @param target the target method handle 477 * @param newType the desired new type. Note that this method does not adapt the method handle completely to the 478 * new type, it only adapts the return type; this is allowed as per 479 * {@link DynamicLinkerFactory#setAutoConversionStrategy(MethodTypeConversionStrategy)}, which is what this method 480 * is used for. 481 * @return the method handle with adapted return type, if it required an unboxing conversion. 482 */ 483 private static MethodHandle unboxReturnType(final MethodHandle target, final MethodType newType) { 484 final MethodType targetType = target.type(); 485 final Class<?> oldReturnType = targetType.returnType(); 486 final Class<?> newReturnType = newType.returnType(); 487 if (TypeUtilities.isWrapperType(oldReturnType)) { 488 if (newReturnType.isPrimitive()) { 489 // The contract of setAutoConversionStrategy is such that the difference between newType and targetType 490 // can only be JLS method invocation conversions. 491 assert TypeUtilities.isMethodInvocationConvertible(oldReturnType, newReturnType); 492 return MethodHandles.explicitCastArguments(target, targetType.changeReturnType(newReturnType)); 493 } 494 } else if (oldReturnType == void.class && newReturnType == Object.class) { 495 return MethodHandles.filterReturnValue(target, VOID_TO_OBJECT); 496 } 497 return target; 498 } 499} 500