Bootstrap.java revision 1793:b4dca6350a46
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 BoundCallableLinker(), 82 new JavaSuperAdapterLinker(beansLinker), 83 new JSObjectLinker(nashornBeansLinker), 84 new BrowserJSObjectLinker(nashornBeansLinker), 85 new ReflectionCheckLinker() 86 }; 87 fallbackLinkers = new GuardingDynamicLinker[] { 88 new NashornStaticClassLinker(beansLinker), 89 nashornBeansLinker, 90 new NashornBottomLinker() 91 }; 92 } 93 94 // do not create me!! 95 private Bootstrap() { 96 } 97 98 /** 99 * Returns a list of exposed nashorn dynalink linkers. 100 * 101 * @return a list of exposed nashorn dynalink linkers. 102 */ 103 public static List<GuardingDynamicLinker> getExposedLinkers() { 104 // we have to create BeansLinker without nashorn specific missing member handler! 105 // Or else, we'd return values such as 'undefined' to the external world! 106 final NashornBeansLinker nbl = new NashornBeansLinker(new BeansLinker()); 107 final JSObjectLinker linker = new JSObjectLinker(nbl); 108 return Collections.singletonList(linker); 109 } 110 111 /** 112 * Creates a Nashorn dynamic linker with the given app class loader. 113 * @param appLoader the app class loader. It will be used to discover 114 * additional language runtime linkers (if any). 115 * @param unstableRelinkThreshold the unstable relink threshold 116 * @return a newly created dynamic linker. 117 */ 118 public static DynamicLinker createDynamicLinker(final ClassLoader appLoader, 119 final int unstableRelinkThreshold) { 120 final DynamicLinkerFactory factory = new DynamicLinkerFactory(); 121 factory.setPrioritizedLinkers(prioritizedLinkers); 122 factory.setFallbackLinkers(fallbackLinkers); 123 factory.setSyncOnRelink(true); 124 factory.setPrelinkTransformer((inv, request, linkerServices) -> { 125 final CallSiteDescriptor desc = request.getCallSiteDescriptor(); 126 return OptimisticReturnFilters.filterOptimisticReturnValue(inv, desc).asType(linkerServices, desc.getMethodType()); 127 }); 128 factory.setAutoConversionStrategy(Bootstrap::unboxReturnType); 129 factory.setInternalObjectsFilter(NashornBeansLinker.createHiddenObjectFilter()); 130 factory.setUnstableRelinkThreshold(unstableRelinkThreshold); 131 132 // Linkers for any additional language runtimes deployed alongside Nashorn will be picked up by the factory. 133 factory.setClassLoader(appLoader); 134 return factory.createLinker(); 135 } 136 137 /** 138 * Returns a dynamic linker for the specific Java class using beans semantics. 139 * @param clazz the Java class 140 * @return a dynamic linker for the specific Java class using beans semantics. 141 */ 142 public static TypeBasedGuardingDynamicLinker getBeanLinkerForClass(final Class<?> clazz) { 143 return beansLinker.getLinkerForClass(clazz); 144 } 145 146 /** 147 * Returns if the given object is a "callable" 148 * @param obj object to be checked for callability 149 * @return true if the obj is callable 150 */ 151 public static boolean isCallable(final Object obj) { 152 if (obj == ScriptRuntime.UNDEFINED || obj == null) { 153 return false; 154 } 155 156 return obj instanceof ScriptFunction || 157 isJSObjectFunction(obj) || 158 BeansLinker.isDynamicMethod(obj) || 159 obj instanceof BoundCallable || 160 isFunctionalInterfaceObject(obj) || 161 obj instanceof StaticClass; 162 } 163 164 /** 165 * Returns true if the given object is a strict callable 166 * @param callable the callable object to be checked for strictness 167 * @return true if the obj is a strict callable, false if it is a non-strict callable. 168 * @throws ECMAException with {@code TypeError} if the object is not a callable. 169 */ 170 public static boolean isStrictCallable(final Object callable) { 171 if (callable instanceof ScriptFunction) { 172 return ((ScriptFunction)callable).isStrict(); 173 } else if (isJSObjectFunction(callable)) { 174 return ((JSObject)callable).isStrictFunction(); 175 } else if (callable instanceof BoundCallable) { 176 return isStrictCallable(((BoundCallable)callable).getCallable()); 177 } else if (BeansLinker.isDynamicMethod(callable) || 178 callable instanceof StaticClass || 179 isFunctionalInterfaceObject(callable)) { 180 return false; 181 } 182 throw notFunction(callable); 183 } 184 185 private static ECMAException notFunction(final Object obj) { 186 return typeError("not.a.function", ScriptRuntime.safeToString(obj)); 187 } 188 189 private static boolean isJSObjectFunction(final Object obj) { 190 return obj instanceof JSObject && ((JSObject)obj).isFunction(); 191 } 192 193 /** 194 * Returns if the given object is a dynalink Dynamic method 195 * @param obj object to be checked 196 * @return true if the obj is a dynamic method 197 */ 198 public static boolean isDynamicMethod(final Object obj) { 199 return BeansLinker.isDynamicMethod(obj instanceof BoundCallable ? ((BoundCallable)obj).getCallable() : obj); 200 } 201 202 /** 203 * Returns if the given object is an instance of an interface annotated with 204 * java.lang.FunctionalInterface 205 * @param obj object to be checked 206 * @return true if the obj is an instance of @FunctionalInterface interface 207 */ 208 public static boolean isFunctionalInterfaceObject(final Object obj) { 209 return !JSType.isPrimitive(obj) && (NashornBeansLinker.getFunctionalInterfaceMethodName(obj.getClass()) != null); 210 } 211 212 /** 213 * Create a call site and link it for Nashorn. This version of the method conforms to the invokedynamic bootstrap 214 * method expected signature and is referenced from Nashorn generated bytecode as the bootstrap method for all 215 * invokedynamic instructions. 216 * @param lookup MethodHandle lookup. 217 * @param opDesc Dynalink dynamic operation descriptor. 218 * @param type Method type. 219 * @param flags flags for call type, trace/profile etc. 220 * @return CallSite with MethodHandle to appropriate method or null if not found. 221 */ 222 public static CallSite bootstrap(final Lookup lookup, final String opDesc, final MethodType type, final int flags) { 223 return Context.getDynamicLinker(lookup.lookupClass()).link(LinkerCallSite.newLinkerCallSite(lookup, opDesc, type, flags)); 224 } 225 226 /** 227 * Returns a dynamic invoker for a specified dynamic operation using the 228 * public lookup. You can use this method to create a method handle that 229 * when invoked acts completely as if it were a Nashorn-linked call site. 230 * Note that the available operations are encoded in the flags, see 231 * {@link NashornCallSiteDescriptor} operation constants. If the operation 232 * takes a name, it should be set otherwise empty name (not null) should be 233 * used. All names (including the empty one) should be encoded using 234 * {@link NameCodec#encode(String)}. Few examples: 235 * <ul> 236 * <li>Get a named property with fixed name: 237 * <pre> 238 * MethodHandle getColor = Boostrap.createDynamicInvoker( 239 * "color", 240 * NashornCallSiteDescriptor.GET_PROPERTY, 241 * Object.class, Object.class); 242 * Object obj = ...; // somehow obtain the object 243 * Object color = getColor.invokeExact(obj); 244 * </pre> 245 * </li> 246 * <li>Get a named property with variable name: 247 * <pre> 248 * MethodHandle getProperty = Boostrap.createDynamicInvoker( 249 * NameCodec.encode(""), 250 * NashornCallSiteDescriptor.GET_PROPERTY, 251 * Object.class, Object.class, String.class); 252 * Object obj = ...; // somehow obtain the object 253 * Object color = getProperty.invokeExact(obj, "color"); 254 * Object shape = getProperty.invokeExact(obj, "shape"); 255 * 256 * MethodHandle getNumProperty = Boostrap.createDynamicInvoker( 257 * NameCodec.encode(""), 258 * NashornCallSiteDescriptor.GET_ELEMENT, 259 * Object.class, Object.class, int.class); 260 * Object elem42 = getNumProperty.invokeExact(obj, 42); 261 * </pre> 262 * </li> 263 * <li>Set a named property with fixed name: 264 * <pre> 265 * MethodHandle setColor = Boostrap.createDynamicInvoker( 266 * "color", 267 * NashornCallSiteDescriptor.SET_PROPERTY, 268 * void.class, Object.class, Object.class); 269 * Object obj = ...; // somehow obtain the object 270 * setColor.invokeExact(obj, Color.BLUE); 271 * </pre> 272 * </li> 273 * <li>Set a property with variable name: 274 * <pre> 275 * MethodHandle setProperty = Boostrap.createDynamicInvoker( 276 * NameCodec.encode(""), 277 * NashornCallSiteDescriptor.SET_PROPERTY, 278 * void.class, Object.class, String.class, Object.class); 279 * Object obj = ...; // somehow obtain the object 280 * setProperty.invokeExact(obj, "color", Color.BLUE); 281 * setProperty.invokeExact(obj, "shape", Shape.CIRCLE); 282 * </pre> 283 * </li> 284 * <li>Call a function on an object; note it's a two-step process: get the 285 * method, then invoke the method. This is the actual: 286 * <pre> 287 * MethodHandle findFooFunction = Boostrap.createDynamicInvoker( 288 * "foo", 289 * NashornCallSiteDescriptor.GET_METHOD, 290 * Object.class, Object.class); 291 * Object obj = ...; // somehow obtain the object 292 * Object foo_fn = findFooFunction.invokeExact(obj); 293 * MethodHandle callFunctionWithTwoArgs = Boostrap.createDynamicCallInvoker( 294 * Object.class, Object.class, Object.class, Object.class, Object.class); 295 * // Note: "call" operation takes a function, then a "this" value, then the arguments: 296 * Object foo_retval = callFunctionWithTwoArgs.invokeExact(foo_fn, obj, arg1, arg2); 297 * </pre> 298 * </li> 299 * </ul> 300 * Few additional remarks: 301 * <ul> 302 * <li>Just as Nashorn works with any Java object, the invokers returned 303 * from this method can also be applied to arbitrary Java objects in 304 * addition to Nashorn JavaScript objects.</li> 305 * <li>For invoking a named function on an object, you can also use the 306 * {@link InvokeByName} convenience class.</li> 307 * <li>There's no rule that the variable property identifier has to be a 308 * {@code String} for {@code GET_PROPERTY/SET_PROPERTY} and {@code int} for 309 * {@code GET_ELEMENT/SET_ELEMENT}. You can declare their type to be 310 * {@code int}, {@code double}, {@code Object}, and so on regardless of the 311 * kind of the operation.</li> 312 * <li>You can be as specific in parameter types as you want. E.g. if you 313 * know that the receiver of the operation will always be 314 * {@code ScriptObject}, you can pass {@code ScriptObject.class} as its 315 * parameter type. If you happen to link to a method that expects different 316 * types, (you can use these invokers on POJOs too, after all, and end up 317 * linking with their methods that have strongly-typed signatures), all 318 * necessary conversions allowed by either Java or JavaScript will be 319 * applied: if invoked methods specify either primitive or wrapped Java 320 * numeric types, or {@code String} or {@code boolean/Boolean}, then the 321 * parameters might be subjected to standard ECMAScript {@code ToNumber}, 322 * {@code ToString}, and {@code ToBoolean} conversion, respectively. Less 323 * obviously, if the expected parameter type is a SAM type, and you pass a 324 * JavaScript function, a proxy object implementing the SAM type and 325 * delegating to the function will be passed. Linkage can often be optimized 326 * when linkers have more specific type information than "everything can be 327 * an object".</li> 328 * <li>You can also be as specific in return types as you want. For return 329 * types any necessary type conversion available in either Java or 330 * JavaScript will be automatically applied, similar to the process 331 * described for parameters, only in reverse direction: if you specify any 332 * either primitive or wrapped Java numeric type, or {@code String} or 333 * {@code boolean/Boolean}, then the return values will be subjected to 334 * standard ECMAScript {@code ToNumber}, {@code ToString}, and 335 * {@code ToBoolean} conversion, respectively. Less obviously, if the return 336 * type is a SAM type, and the return value is a JavaScript function, a 337 * proxy object implementing the SAM type and delegating to the function 338 * will be returned.</li> 339 * </ul> 340 * @param name name at the call site. Must not be null. Must be encoded 341 * using {@link NameCodec#encode(String)}. If the operation does not take a 342 * name, use empty string (also has to be encoded). 343 * @param flags the call site flags for the operation; see 344 * {@link NashornCallSiteDescriptor} for available flags. The most important 345 * part of the flags are the ones encoding the actual operation. 346 * @param rtype the return type for the operation 347 * @param ptypes the parameter types for the operation 348 * @return MethodHandle for invoking the operation. 349 */ 350 public static MethodHandle createDynamicInvoker(final String name, final int flags, final Class<?> rtype, final Class<?>... ptypes) { 351 return bootstrap(MethodHandles.publicLookup(), name, MethodType.methodType(rtype, ptypes), flags).dynamicInvoker(); 352 } 353 354 /** 355 * Returns a dynamic invoker for the {@link NashornCallSiteDescriptor#CALL} 356 * operation using the public lookup. 357 * @param rtype the return type for the operation 358 * @param ptypes the parameter types for the operation 359 * @return a dynamic invoker for the {@code CALL} operation. 360 */ 361 public static MethodHandle createDynamicCallInvoker(final Class<?> rtype, final Class<?>... ptypes) { 362 return createDynamicInvoker("", NashornCallSiteDescriptor.CALL, rtype, ptypes); 363 } 364 365 /** 366 * Returns a dynamic invoker for a specified dynamic operation using the 367 * public lookup. Similar to 368 * {@link #createDynamicInvoker(String, int, Class, Class...)} but with 369 * already precomposed method type. 370 * @param name name at the call site. 371 * @param flags flags at the call site 372 * @param type the method type for the operation 373 * @return MethodHandle for invoking the operation. 374 */ 375 public static MethodHandle createDynamicInvoker(final String name, final int flags, final MethodType type) { 376 return bootstrap(MethodHandles.publicLookup(), name, type, flags).dynamicInvoker(); 377 } 378 379 /** 380 * Binds any object Nashorn can use as a [[Callable]] to a receiver and optionally arguments. 381 * @param callable the callable to bind 382 * @param boundThis the bound "this" value. 383 * @param boundArgs the bound arguments. Can be either null or empty array to signify no arguments are bound. 384 * @return a bound callable. 385 * @throws ECMAException with {@code TypeError} if the object is not a callable. 386 */ 387 public static Object bindCallable(final Object callable, final Object boundThis, final Object[] boundArgs) { 388 if (callable instanceof ScriptFunction) { 389 return ((ScriptFunction)callable).createBound(boundThis, boundArgs); 390 } else if (callable instanceof BoundCallable) { 391 return ((BoundCallable)callable).bind(boundArgs); 392 } else if (isCallable(callable)) { 393 return new BoundCallable(callable, boundThis, boundArgs); 394 } 395 throw notFunction(callable); 396 } 397 398 /** 399 * Creates a super-adapter for an adapter, that is, an adapter to the adapter that allows invocation of superclass 400 * methods on it. 401 * @param adapter the original adapter 402 * @return a new adapter that can be used to invoke super methods on the original adapter. 403 */ 404 public static Object createSuperAdapter(final Object adapter) { 405 return new JavaSuperAdapter(adapter); 406 } 407 408 /** 409 * If the given class is a reflection-specific class (anything in {@code java.lang.reflect} and 410 * {@code java.lang.invoke} package, as well a {@link Class} and any subclass of {@link ClassLoader}) and there is 411 * a security manager in the system, then it checks the {@code nashorn.JavaReflection} {@code RuntimePermission}. 412 * @param clazz the class being tested 413 * @param isStatic is access checked for static members (or instance members) 414 */ 415 public static void checkReflectionAccess(final Class<?> clazz, final boolean isStatic) { 416 ReflectionCheckLinker.checkReflectionAccess(clazz, isStatic); 417 } 418 419 /** 420 * Returns the Nashorn's internally used dynamic linker's services object. Note that in code that is processing a 421 * linking request, you will normally use the {@code LinkerServices} object passed by whatever top-level linker 422 * invoked the linking (if the call site is in Nashorn-generated code, you'll get this object anyway). You should 423 * only resort to retrieving a linker services object using this method when you need some linker services (e.g. 424 * type converter method handles) outside of a code path that is linking a call site. 425 * @return Nashorn's internal dynamic linker's services object. 426 */ 427 public static LinkerServices getLinkerServices() { 428 return Context.getDynamicLinker().getLinkerServices(); 429 } 430 431 /** 432 * Takes a guarded invocation, and ensures its method and guard conform to the type of the call descriptor, using 433 * all type conversions allowed by the linker's services. This method is used by Nashorn's linkers as a last step 434 * before returning guarded invocations. Most of the code used to produce the guarded invocations does not make an 435 * effort to coordinate types of the methods, and so a final type adjustment before a guarded invocation is returned 436 * to the aggregating linker is the responsibility of the linkers themselves. 437 * @param inv the guarded invocation that needs to be type-converted. Can be null. 438 * @param linkerServices the linker services object providing the type conversions. 439 * @param desc the call site descriptor to whose method type the invocation needs to conform. 440 * @return the type-converted guarded invocation. If input is null, null is returned. If the input invocation 441 * already conforms to the requested type, it is returned unchanged. 442 */ 443 static GuardedInvocation asTypeSafeReturn(final GuardedInvocation inv, final LinkerServices linkerServices, final CallSiteDescriptor desc) { 444 return inv == null ? null : inv.asTypeSafeReturn(linkerServices, desc.getMethodType()); 445 } 446 447 /** 448 * Adapts the return type of the method handle with {@code explicitCastArguments} when it is an unboxing 449 * conversion. This will ensure that nulls are unwrapped to false or 0. 450 * @param target the target method handle 451 * @param newType the desired new type. Note that this method does not adapt the method handle completely to the 452 * new type, it only adapts the return type; this is allowed as per 453 * {@link DynamicLinkerFactory#setAutoConversionStrategy(MethodTypeConversionStrategy)}, which is what this method 454 * is used for. 455 * @return the method handle with adapted return type, if it required an unboxing conversion. 456 */ 457 private static MethodHandle unboxReturnType(final MethodHandle target, final MethodType newType) { 458 final MethodType targetType = target.type(); 459 final Class<?> oldReturnType = targetType.returnType(); 460 final Class<?> newReturnType = newType.returnType(); 461 if (TypeUtilities.isWrapperType(oldReturnType)) { 462 if (newReturnType.isPrimitive()) { 463 // The contract of setAutoConversionStrategy is such that the difference between newType and targetType 464 // can only be JLS method invocation conversions. 465 assert TypeUtilities.isMethodInvocationConvertible(oldReturnType, newReturnType); 466 return MethodHandles.explicitCastArguments(target, targetType.changeReturnType(newReturnType)); 467 } 468 } else if (oldReturnType == void.class && newReturnType == Object.class) { 469 return MethodHandles.filterReturnValue(target, VOID_TO_OBJECT); 470 } 471 return target; 472 } 473 474 private static MethodHandle createMissingMemberHandler( 475 final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception { 476 if (BrowserJSObjectLinker.canLinkTypeStatic(linkRequest.getReceiver().getClass())) { 477 // Don't create missing member handlers for the browser JS objects as they 478 // have their own logic. 479 return null; 480 } 481 return NashornBottomLinker.linkMissingBeanMember(linkRequest, linkerServices); 482 } 483} 484