Bootstrap.java revision 1704:9c62b456f075
1/* 2 * Copyright (c) 2010, 2016, 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.MethodHandle; 33import java.lang.invoke.MethodHandles; 34import java.lang.invoke.MethodHandles.Lookup; 35import java.lang.invoke.MethodType; 36import java.util.Collections; 37import java.util.List; 38import jdk.dynalink.CallSiteDescriptor; 39import jdk.dynalink.DynamicLinker; 40import jdk.dynalink.DynamicLinkerFactory; 41import jdk.dynalink.beans.BeansLinker; 42import jdk.dynalink.beans.StaticClass; 43import jdk.dynalink.linker.GuardedInvocation; 44import jdk.dynalink.linker.GuardingDynamicLinker; 45import jdk.dynalink.linker.LinkRequest; 46import jdk.dynalink.linker.LinkerServices; 47import jdk.dynalink.linker.MethodTypeConversionStrategy; 48import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker; 49import jdk.dynalink.linker.support.TypeUtilities; 50import jdk.nashorn.api.scripting.JSObject; 51import jdk.nashorn.internal.codegen.CompilerConstants.Call; 52import jdk.nashorn.internal.lookup.MethodHandleFactory; 53import jdk.nashorn.internal.lookup.MethodHandleFunctionality; 54import jdk.nashorn.internal.runtime.Context; 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; 60 61/** 62 * This class houses bootstrap method for invokedynamic instructions generated by compiler. 63 */ 64public final class Bootstrap { 65 /** Reference to the seed boostrap function */ 66 public static final Call BOOTSTRAP = staticCallNoLookup(Bootstrap.class, "bootstrap", CallSite.class, Lookup.class, String.class, MethodType.class, int.class); 67 68 private static final MethodHandleFunctionality MH = MethodHandleFactory.getFunctionality(); 69 70 private static final MethodHandle VOID_TO_OBJECT = MH.constant(Object.class, ScriptRuntime.UNDEFINED); 71 72 private static final BeansLinker beansLinker = new BeansLinker(Bootstrap::createMissingMemberHandler); 73 private static final GuardingDynamicLinker[] prioritizedLinkers; 74 private static final GuardingDynamicLinker[] fallbackLinkers; 75 76 static { 77 final NashornBeansLinker nashornBeansLinker = new NashornBeansLinker(beansLinker); 78 prioritizedLinkers = new GuardingDynamicLinker[] { 79 new NashornLinker(), 80 new NashornPrimitiveLinker(), 81 new NashornStaticClassLinker(beansLinker), 82 new BoundCallableLinker(), 83 new JavaSuperAdapterLinker(beansLinker), 84 new JSObjectLinker(nashornBeansLinker), 85 new BrowserJSObjectLinker(nashornBeansLinker), 86 new ReflectionCheckLinker() 87 }; 88 fallbackLinkers = new GuardingDynamicLinker[] {nashornBeansLinker, new NashornBottomLinker() }; 89 } 90 91 // do not create me!! 92 private Bootstrap() { 93 } 94 95 /** 96 * Returns a list of exposed nashorn dynalink linkers. 97 * 98 * @return a list of exposed nashorn dynalink linkers. 99 */ 100 public static List<GuardingDynamicLinker> getExposedLinkers() { 101 // we have to create BeansLinker without nashorn specific missing member handler! 102 // Or else, we'd return values such as 'undefined' to the external world! 103 final NashornBeansLinker nbl = new NashornBeansLinker(new BeansLinker()); 104 final JSObjectLinker linker = new JSObjectLinker(nbl); 105 return Collections.singletonList(linker); 106 } 107 108 /** 109 * Creates a Nashorn dynamic linker with the given app class loader. 110 * @param appLoader the app class loader. It will be used to discover 111 * additional language runtime linkers (if any). 112 * @param unstableRelinkThreshold the unstable relink threshold 113 * @return a newly created dynamic linker. 114 */ 115 public static DynamicLinker createDynamicLinker(final ClassLoader appLoader, 116 final int unstableRelinkThreshold) { 117 final DynamicLinkerFactory factory = new DynamicLinkerFactory(); 118 factory.setPrioritizedLinkers(prioritizedLinkers); 119 factory.setFallbackLinkers(fallbackLinkers); 120 factory.setSyncOnRelink(true); 121 factory.setPrelinkTransformer((inv, request, linkerServices) -> { 122 final CallSiteDescriptor desc = request.getCallSiteDescriptor(); 123 return OptimisticReturnFilters.filterOptimisticReturnValue(inv, desc).asType(linkerServices, desc.getMethodType()); 124 }); 125 factory.setAutoConversionStrategy(Bootstrap::unboxReturnType); 126 factory.setInternalObjectsFilter(NashornBeansLinker.createHiddenObjectFilter()); 127 factory.setUnstableRelinkThreshold(unstableRelinkThreshold); 128 129 // Linkers for any additional language runtimes deployed alongside Nashorn will be picked up by the factory. 130 factory.setClassLoader(appLoader); 131 return factory.createLinker(); 132 } 133 134 /** 135 * Returns a dynamic linker for the specific Java class using beans semantics. 136 * @param clazz the Java class 137 * @return a dynamic linker for the specific Java class using beans semantics. 138 */ 139 public static TypeBasedGuardingDynamicLinker getBeanLinkerForClass(final Class<?> clazz) { 140 return beansLinker.getLinkerForClass(clazz); 141 } 142 143 /** 144 * Returns if the given object is a "callable" 145 * @param obj object to be checked for callability 146 * @return true if the obj is callable 147 */ 148 public static boolean isCallable(final Object obj) { 149 if (obj == ScriptRuntime.UNDEFINED || obj == null) { 150 return false; 151 } 152 153 return obj instanceof ScriptFunction || 154 isJSObjectFunction(obj) || 155 BeansLinker.isDynamicMethod(obj) || 156 obj instanceof BoundCallable || 157 isFunctionalInterfaceObject(obj) || 158 obj instanceof StaticClass; 159 } 160 161 /** 162 * Returns true if the given object is a strict callable 163 * @param callable the callable object to be checked for strictness 164 * @return true if the obj is a strict callable, false if it is a non-strict callable. 165 * @throws ECMAException with {@code TypeError} if the object is not a callable. 166 */ 167 public static boolean isStrictCallable(final Object callable) { 168 if (callable instanceof ScriptFunction) { 169 return ((ScriptFunction)callable).isStrict(); 170 } else if (isJSObjectFunction(callable)) { 171 return ((JSObject)callable).isStrictFunction(); 172 } else if (callable instanceof BoundCallable) { 173 return isStrictCallable(((BoundCallable)callable).getCallable()); 174 } else if (BeansLinker.isDynamicMethod(callable) || 175 callable instanceof StaticClass || 176 isFunctionalInterfaceObject(callable)) { 177 return false; 178 } 179 throw notFunction(callable); 180 } 181 182 private static ECMAException notFunction(final Object obj) { 183 return typeError("not.a.function", ScriptRuntime.safeToString(obj)); 184 } 185 186 private static boolean isJSObjectFunction(final Object obj) { 187 return obj instanceof JSObject && ((JSObject)obj).isFunction(); 188 } 189 190 /** 191 * Returns if the given object is a dynalink Dynamic method 192 * @param obj object to be checked 193 * @return true if the obj is a dynamic method 194 */ 195 public static boolean isDynamicMethod(final Object obj) { 196 return BeansLinker.isDynamicMethod(obj instanceof BoundCallable ? ((BoundCallable)obj).getCallable() : obj); 197 } 198 199 /** 200 * Returns if the given object is an instance of an interface annotated with 201 * java.lang.FunctionalInterface 202 * @param obj object to be checked 203 * @return true if the obj is an instance of @FunctionalInterface interface 204 */ 205 public static boolean isFunctionalInterfaceObject(final Object obj) { 206 return !JSType.isPrimitive(obj) && (NashornBeansLinker.getFunctionalInterfaceMethodName(obj.getClass()) != null); 207 } 208 209 /** 210 * Create a call site and link it for Nashorn. This version of the method conforms to the invokedynamic bootstrap 211 * method expected signature and is referenced from Nashorn generated bytecode as the bootstrap method for all 212 * invokedynamic instructions. 213 * @param lookup MethodHandle lookup. 214 * @param opDesc Dynalink dynamic operation descriptor. 215 * @param type Method type. 216 * @param flags flags for call type, trace/profile etc. 217 * @return CallSite with MethodHandle to appropriate method or null if not found. 218 */ 219 public static CallSite bootstrap(final Lookup lookup, final String opDesc, final MethodType type, final int flags) { 220 return Context.getDynamicLinker(lookup.lookupClass()).link(LinkerCallSite.newLinkerCallSite(lookup, opDesc, type, flags)); 221 } 222 223 /** 224 * Returns a dynamic invoker for a specified dynamic operation using the 225 * public lookup. You can use this method to create a method handle that 226 * when invoked acts completely as if it were a Nashorn-linked call site. 227 * Note that the available operations are encoded in the flags, see 228 * {@link NashornCallSiteDescriptor} operation constants. If the operation 229 * takes a name, it should be set otherwise empty name (not null) should be 230 * used. All names (including the empty one) should be encoded using 231 * {@link NameCodec#encode(String)}. Few examples: 232 * <ul> 233 * <li>Get a named property with fixed name: 234 * <pre> 235 * MethodHandle getColor = Boostrap.createDynamicInvoker( 236 * "color", 237 * NashornCallSiteDescriptor.GET_PROPERTY, 238 * Object.class, Object.class); 239 * Object obj = ...; // somehow obtain the object 240 * Object color = getColor.invokeExact(obj); 241 * </pre> 242 * </li> 243 * <li>Get a named property with variable name: 244 * <pre> 245 * MethodHandle getProperty = Boostrap.createDynamicInvoker( 246 * NameCodec.encode(""), 247 * NashornCallSiteDescriptor.GET_PROPERTY, 248 * Object.class, Object.class, String.class); 249 * Object obj = ...; // somehow obtain the object 250 * Object color = getProperty.invokeExact(obj, "color"); 251 * Object shape = getProperty.invokeExact(obj, "shape"); 252 * 253 * MethodHandle getNumProperty = Boostrap.createDynamicInvoker( 254 * NameCodec.encode(""), 255 * NashornCallSiteDescriptor.GET_ELEMENT, 256 * Object.class, Object.class, int.class); 257 * Object elem42 = getNumProperty.invokeExact(obj, 42); 258 * </pre> 259 * </li> 260 * <li>Set a named property with fixed name: 261 * <pre> 262 * MethodHandle setColor = Boostrap.createDynamicInvoker( 263 * "color", 264 * NashornCallSiteDescriptor.SET_PROPERTY, 265 * void.class, Object.class, Object.class); 266 * Object obj = ...; // somehow obtain the object 267 * setColor.invokeExact(obj, Color.BLUE); 268 * </pre> 269 * </li> 270 * <li>Set a property with variable name: 271 * <pre> 272 * MethodHandle setProperty = Boostrap.createDynamicInvoker( 273 * NameCodec.encode(""), 274 * NashornCallSiteDescriptor.SET_PROPERTY, 275 * void.class, Object.class, String.class, Object.class); 276 * Object obj = ...; // somehow obtain the object 277 * setProperty.invokeExact(obj, "color", Color.BLUE); 278 * setProperty.invokeExact(obj, "shape", Shape.CIRCLE); 279 * </pre> 280 * </li> 281 * <li>Call a function on an object; note it's a two-step process: get the 282 * method, then invoke the method. This is the actual: 283 * <pre> 284 * MethodHandle findFooFunction = Boostrap.createDynamicInvoker( 285 * "foo", 286 * NashornCallSiteDescriptor.GET_METHOD, 287 * Object.class, Object.class); 288 * Object obj = ...; // somehow obtain the object 289 * Object foo_fn = findFooFunction.invokeExact(obj); 290 * MethodHandle callFunctionWithTwoArgs = Boostrap.createDynamicCallInvoker( 291 * Object.class, Object.class, Object.class, Object.class, Object.class); 292 * // Note: "call" operation takes a function, then a "this" value, then the arguments: 293 * Object foo_retval = callFunctionWithTwoArgs.invokeExact(foo_fn, obj, arg1, arg2); 294 * </pre> 295 * </li> 296 * </ul> 297 * Few additional remarks: 298 * <ul> 299 * <li>Just as Nashorn works with any Java object, the invokers returned 300 * from this method can also be applied to arbitrary Java objects in 301 * addition to Nashorn JavaScript objects.</li> 302 * <li>For invoking a named function on an object, you can also use the 303 * {@link InvokeByName} convenience class.</li> 304 * <li>There's no rule that the variable property identifier has to be a 305 * {@code String} for {@code GET_PROPERTY/SET_PROPERTY} and {@code int} for 306 * {@code GET_ELEMENT/SET_ELEMENT}. You can declare their type to be 307 * {@code int}, {@code double}, {@code Object}, and so on regardless of the 308 * kind of the operation.</li> 309 * <li>You can be as specific in parameter types as you want. E.g. if you 310 * know that the receiver of the operation will always be 311 * {@code ScriptObject}, you can pass {@code ScriptObject.class} as its 312 * parameter type. If you happen to link to a method that expects different 313 * types, (you can use these invokers on POJOs too, after all, and end up 314 * linking with their methods that have strongly-typed signatures), all 315 * necessary conversions allowed by either Java or JavaScript will be 316 * applied: if invoked methods specify either primitive or wrapped Java 317 * numeric types, or {@code String} or {@code boolean/Boolean}, then the 318 * parameters might be subjected to standard ECMAScript {@code ToNumber}, 319 * {@code ToString}, and {@code ToBoolean} conversion, respectively. Less 320 * obviously, if the expected parameter type is a SAM type, and you pass a 321 * JavaScript function, a proxy object implementing the SAM type and 322 * delegating to the function will be passed. Linkage can often be optimized 323 * when linkers have more specific type information than "everything can be 324 * an object".</li> 325 * <li>You can also be as specific in return types as you want. For return 326 * types any necessary type conversion available in either Java or 327 * JavaScript will be automatically applied, similar to the process 328 * described for parameters, only in reverse direction: if you specify any 329 * either primitive or wrapped Java numeric type, or {@code String} or 330 * {@code boolean/Boolean}, then the return values will be subjected to 331 * standard ECMAScript {@code ToNumber}, {@code ToString}, and 332 * {@code ToBoolean} conversion, respectively. Less obviously, if the return 333 * type is a SAM type, and the return value is a JavaScript function, a 334 * proxy object implementing the SAM type and delegating to the function 335 * will be returned.</li> 336 * </ul> 337 * @param name name at the call site. Must not be null. Must be encoded 338 * using {@link NameCodec#encode(String)}. If the operation does not take a 339 * name, use empty string (also has to be encoded). 340 * @param flags the call site flags for the operation; see 341 * {@link NashornCallSiteDescriptor} for available flags. The most important 342 * part of the flags are the ones encoding the actual operation. 343 * @param rtype the return type for the operation 344 * @param ptypes the parameter types for the operation 345 * @return MethodHandle for invoking the operation. 346 */ 347 public static MethodHandle createDynamicInvoker(final String name, final int flags, final Class<?> rtype, final Class<?>... ptypes) { 348 return bootstrap(MethodHandles.publicLookup(), name, MethodType.methodType(rtype, ptypes), flags).dynamicInvoker(); 349 } 350 351 /** 352 * Returns a dynamic invoker for the {@link NashornCallSiteDescriptor#CALL} 353 * operation using the public lookup. 354 * @param rtype the return type for the operation 355 * @param ptypes the parameter types for the operation 356 * @return a dynamic invoker for the {@code CALL} operation. 357 */ 358 public static MethodHandle createDynamicCallInvoker(final Class<?> rtype, final Class<?>... ptypes) { 359 return createDynamicInvoker("", NashornCallSiteDescriptor.CALL, rtype, ptypes); 360 } 361 362 /** 363 * Returns a dynamic invoker for a specified dynamic operation using the 364 * public lookup. Similar to 365 * {@link #createDynamicInvoker(String, int, Class, Class...)} but with 366 * already precomposed method type. 367 * @param name name at the call site. 368 * @param flags flags at the call site 369 * @param type the method type for the operation 370 * @return MethodHandle for invoking the operation. 371 */ 372 public static MethodHandle createDynamicInvoker(final String name, final int flags, final MethodType type) { 373 return bootstrap(MethodHandles.publicLookup(), name, type, flags).dynamicInvoker(); 374 } 375 376 /** 377 * Binds any object Nashorn can use as a [[Callable]] to a receiver and optionally arguments. 378 * @param callable the callable to bind 379 * @param boundThis the bound "this" value. 380 * @param boundArgs the bound arguments. Can be either null or empty array to signify no arguments are bound. 381 * @return a bound callable. 382 * @throws ECMAException with {@code TypeError} if the object is not a callable. 383 */ 384 public static Object bindCallable(final Object callable, final Object boundThis, final Object[] boundArgs) { 385 if (callable instanceof ScriptFunction) { 386 return ((ScriptFunction)callable).createBound(boundThis, boundArgs); 387 } else if (callable instanceof BoundCallable) { 388 return ((BoundCallable)callable).bind(boundArgs); 389 } else if (isCallable(callable)) { 390 return new BoundCallable(callable, boundThis, boundArgs); 391 } 392 throw notFunction(callable); 393 } 394 395 /** 396 * Creates a super-adapter for an adapter, that is, an adapter to the adapter that allows invocation of superclass 397 * methods on it. 398 * @param adapter the original adapter 399 * @return a new adapter that can be used to invoke super methods on the original adapter. 400 */ 401 public static Object createSuperAdapter(final Object adapter) { 402 return new JavaSuperAdapter(adapter); 403 } 404 405 /** 406 * If the given class is a reflection-specific class (anything in {@code java.lang.reflect} and 407 * {@code java.lang.invoke} package, as well a {@link Class} and any subclass of {@link ClassLoader}) and there is 408 * a security manager in the system, then it checks the {@code nashorn.JavaReflection} {@code RuntimePermission}. 409 * @param clazz the class being tested 410 * @param isStatic is access checked for static members (or instance members) 411 */ 412 public static void checkReflectionAccess(final Class<?> clazz, final boolean isStatic) { 413 ReflectionCheckLinker.checkReflectionAccess(clazz, isStatic); 414 } 415 416 /** 417 * Returns the Nashorn's internally used dynamic linker's services object. Note that in code that is processing a 418 * linking request, you will normally use the {@code LinkerServices} object passed by whatever top-level linker 419 * invoked the linking (if the call site is in Nashorn-generated code, you'll get this object anyway). You should 420 * only resort to retrieving a linker services object using this method when you need some linker services (e.g. 421 * type converter method handles) outside of a code path that is linking a call site. 422 * @return Nashorn's internal dynamic linker's services object. 423 */ 424 public static LinkerServices getLinkerServices() { 425 return Context.getDynamicLinker().getLinkerServices(); 426 } 427 428 /** 429 * Takes a guarded invocation, and ensures its method and guard conform to the type of the call descriptor, using 430 * all type conversions allowed by the linker's services. This method is used by Nashorn's linkers as a last step 431 * before returning guarded invocations. Most of the code used to produce the guarded invocations does not make an 432 * effort to coordinate types of the methods, and so a final type adjustment before a guarded invocation is returned 433 * to the aggregating linker is the responsibility of the linkers themselves. 434 * @param inv the guarded invocation that needs to be type-converted. Can be null. 435 * @param linkerServices the linker services object providing the type conversions. 436 * @param desc the call site descriptor to whose method type the invocation needs to conform. 437 * @return the type-converted guarded invocation. If input is null, null is returned. If the input invocation 438 * already conforms to the requested type, it is returned unchanged. 439 */ 440 static GuardedInvocation asTypeSafeReturn(final GuardedInvocation inv, final LinkerServices linkerServices, final CallSiteDescriptor desc) { 441 return inv == null ? null : inv.asTypeSafeReturn(linkerServices, desc.getMethodType()); 442 } 443 444 /** 445 * Adapts the return type of the method handle with {@code explicitCastArguments} when it is an unboxing 446 * conversion. This will ensure that nulls are unwrapped to false or 0. 447 * @param target the target method handle 448 * @param newType the desired new type. Note that this method does not adapt the method handle completely to the 449 * new type, it only adapts the return type; this is allowed as per 450 * {@link DynamicLinkerFactory#setAutoConversionStrategy(MethodTypeConversionStrategy)}, which is what this method 451 * is used for. 452 * @return the method handle with adapted return type, if it required an unboxing conversion. 453 */ 454 private static MethodHandle unboxReturnType(final MethodHandle target, final MethodType newType) { 455 final MethodType targetType = target.type(); 456 final Class<?> oldReturnType = targetType.returnType(); 457 final Class<?> newReturnType = newType.returnType(); 458 if (TypeUtilities.isWrapperType(oldReturnType)) { 459 if (newReturnType.isPrimitive()) { 460 // The contract of setAutoConversionStrategy is such that the difference between newType and targetType 461 // can only be JLS method invocation conversions. 462 assert TypeUtilities.isMethodInvocationConvertible(oldReturnType, newReturnType); 463 return MethodHandles.explicitCastArguments(target, targetType.changeReturnType(newReturnType)); 464 } 465 } else if (oldReturnType == void.class && newReturnType == Object.class) { 466 return MethodHandles.filterReturnValue(target, VOID_TO_OBJECT); 467 } 468 return target; 469 } 470 471 private static MethodHandle createMissingMemberHandler( 472 final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception { 473 if (BrowserJSObjectLinker.canLinkTypeStatic(linkRequest.getReceiver().getClass())) { 474 // Don't create missing member handlers for the browser JS objects as they 475 // have their own logic. 476 return null; 477 } 478 return NashornBottomLinker.linkMissingBeanMember(linkRequest, linkerServices); 479 } 480} 481