Bootstrap.java revision 1629:8042e81b530e
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 jdk.dynalink.CallSiteDescriptor; 37import jdk.dynalink.DynamicLinker; 38import jdk.dynalink.DynamicLinkerFactory; 39import jdk.dynalink.beans.BeansLinker; 40import jdk.dynalink.beans.StaticClass; 41import jdk.dynalink.linker.GuardedInvocation; 42import jdk.dynalink.linker.GuardingDynamicLinker; 43import jdk.dynalink.linker.LinkRequest; 44import jdk.dynalink.linker.LinkerServices; 45import jdk.dynalink.linker.MethodTypeConversionStrategy; 46import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker; 47import jdk.dynalink.linker.support.TypeUtilities; 48import jdk.nashorn.api.scripting.JSObject; 49import jdk.nashorn.internal.codegen.CompilerConstants.Call; 50import jdk.nashorn.internal.lookup.MethodHandleFactory; 51import jdk.nashorn.internal.lookup.MethodHandleFunctionality; 52import jdk.nashorn.internal.runtime.Context; 53import jdk.nashorn.internal.runtime.ECMAException; 54import jdk.nashorn.internal.runtime.JSType; 55import jdk.nashorn.internal.runtime.OptimisticReturnFilters; 56import jdk.nashorn.internal.runtime.ScriptFunction; 57import jdk.nashorn.internal.runtime.ScriptRuntime; 58 59/** 60 * This class houses bootstrap method for invokedynamic instructions generated by compiler. 61 */ 62public final class Bootstrap { 63 /** Reference to the seed boostrap function */ 64 public static final Call BOOTSTRAP = staticCallNoLookup(Bootstrap.class, "bootstrap", CallSite.class, Lookup.class, String.class, MethodType.class, int.class); 65 66 private static final MethodHandleFunctionality MH = MethodHandleFactory.getFunctionality(); 67 68 private static final MethodHandle VOID_TO_OBJECT = MH.constant(Object.class, ScriptRuntime.UNDEFINED); 69 70 private static final BeansLinker beansLinker = new BeansLinker(Bootstrap::createMissingMemberHandler); 71 private static final GuardingDynamicLinker[] prioritizedLinkers; 72 private static final GuardingDynamicLinker[] fallbackLinkers; 73 static { 74 final NashornBeansLinker nashornBeansLinker = new NashornBeansLinker(beansLinker); 75 prioritizedLinkers = new GuardingDynamicLinker[] { 76 new NashornLinker(), 77 new NashornPrimitiveLinker(), 78 new NashornStaticClassLinker(beansLinker), 79 new BoundCallableLinker(), 80 new JavaSuperAdapterLinker(beansLinker), 81 new JSObjectLinker(nashornBeansLinker), 82 new BrowserJSObjectLinker(nashornBeansLinker), 83 new ReflectionCheckLinker() 84 }; 85 fallbackLinkers = new GuardingDynamicLinker[] {nashornBeansLinker, new NashornBottomLinker() }; 86 } 87 88 // do not create me!! 89 private Bootstrap() { 90 } 91 92 /** 93 * Creates a Nashorn dynamic linker with the given app class loader. 94 * @param appLoader the app class loader. It will be used to discover 95 * additional language runtime linkers (if any). 96 * @param unstableRelinkThreshold the unstable relink threshold 97 * @return a newly created dynamic linker. 98 */ 99 public static DynamicLinker createDynamicLinker(final ClassLoader appLoader, 100 final int unstableRelinkThreshold) { 101 final DynamicLinkerFactory factory = new DynamicLinkerFactory(); 102 factory.setPrioritizedLinkers(prioritizedLinkers); 103 factory.setFallbackLinkers(fallbackLinkers); 104 factory.setSyncOnRelink(true); 105 factory.setPrelinkTransformer((inv, request, linkerServices) -> { 106 final CallSiteDescriptor desc = request.getCallSiteDescriptor(); 107 return OptimisticReturnFilters.filterOptimisticReturnValue(inv, desc).asType(linkerServices, desc.getMethodType()); 108 }); 109 factory.setAutoConversionStrategy(Bootstrap::unboxReturnType); 110 factory.setInternalObjectsFilter(NashornBeansLinker.createHiddenObjectFilter()); 111 factory.setUnstableRelinkThreshold(unstableRelinkThreshold); 112 113 // Linkers for any additional language runtimes deployed alongside Nashorn will be picked up by the factory. 114 factory.setClassLoader(appLoader); 115 return factory.createLinker(); 116 } 117 118 /** 119 * Returns a dynamic linker for the specific Java class using beans semantics. 120 * @param clazz the Java class 121 * @return a dynamic linker for the specific Java class using beans semantics. 122 */ 123 public static TypeBasedGuardingDynamicLinker getBeanLinkerForClass(final Class<?> clazz) { 124 return beansLinker.getLinkerForClass(clazz); 125 } 126 127 /** 128 * Returns if the given object is a "callable" 129 * @param obj object to be checked for callability 130 * @return true if the obj is callable 131 */ 132 public static boolean isCallable(final Object obj) { 133 if (obj == ScriptRuntime.UNDEFINED || obj == null) { 134 return false; 135 } 136 137 return obj instanceof ScriptFunction || 138 isJSObjectFunction(obj) || 139 BeansLinker.isDynamicMethod(obj) || 140 obj instanceof BoundCallable || 141 isFunctionalInterfaceObject(obj) || 142 obj instanceof StaticClass; 143 } 144 145 /** 146 * Returns true if the given object is a strict callable 147 * @param callable the callable object to be checked for strictness 148 * @return true if the obj is a strict callable, false if it is a non-strict callable. 149 * @throws ECMAException with {@code TypeError} if the object is not a callable. 150 */ 151 public static boolean isStrictCallable(final Object callable) { 152 if (callable instanceof ScriptFunction) { 153 return ((ScriptFunction)callable).isStrict(); 154 } else if (isJSObjectFunction(callable)) { 155 return ((JSObject)callable).isStrictFunction(); 156 } else if (callable instanceof BoundCallable) { 157 return isStrictCallable(((BoundCallable)callable).getCallable()); 158 } else if (BeansLinker.isDynamicMethod(callable) || callable instanceof StaticClass) { 159 return false; 160 } 161 throw notFunction(callable); 162 } 163 164 private static ECMAException notFunction(final Object obj) { 165 return typeError("not.a.function", ScriptRuntime.safeToString(obj)); 166 } 167 168 private static boolean isJSObjectFunction(final Object obj) { 169 return obj instanceof JSObject && ((JSObject)obj).isFunction(); 170 } 171 172 /** 173 * Returns if the given object is a dynalink Dynamic method 174 * @param obj object to be checked 175 * @return true if the obj is a dynamic method 176 */ 177 public static boolean isDynamicMethod(final Object obj) { 178 return BeansLinker.isDynamicMethod(obj instanceof BoundCallable ? ((BoundCallable)obj).getCallable() : obj); 179 } 180 181 /** 182 * Returns if the given object is an instance of an interface annotated with 183 * java.lang.FunctionalInterface 184 * @param obj object to be checked 185 * @return true if the obj is an instance of @FunctionalInterface interface 186 */ 187 public static boolean isFunctionalInterfaceObject(final Object obj) { 188 return !JSType.isPrimitive(obj) && (NashornBeansLinker.getFunctionalInterfaceMethodName(obj.getClass()) != null); 189 } 190 191 /** 192 * Create a call site and link it for Nashorn. This version of the method conforms to the invokedynamic bootstrap 193 * method expected signature and is referenced from Nashorn generated bytecode as the bootstrap method for all 194 * invokedynamic instructions. 195 * @param lookup MethodHandle lookup. 196 * @param opDesc Dynalink dynamic operation descriptor. 197 * @param type Method type. 198 * @param flags flags for call type, trace/profile etc. 199 * @return CallSite with MethodHandle to appropriate method or null if not found. 200 */ 201 public static CallSite bootstrap(final Lookup lookup, final String opDesc, final MethodType type, final int flags) { 202 return Context.getDynamicLinker(lookup.lookupClass()).link(LinkerCallSite.newLinkerCallSite(lookup, opDesc, type, flags)); 203 } 204 205 /** 206 * Returns a dynamic invoker for a specified dynamic operation using the 207 * public lookup. You can use this method to create a method handle that 208 * when invoked acts completely as if it were a Nashorn-linked call site. 209 * Note that the available operations are encoded in the flags, see 210 * {@link NashornCallSiteDescriptor} operation constants. If the operation 211 * takes a name, it should be set otherwise empty name (not null) should be 212 * used. All names (including the empty one) should be encoded using 213 * {@link NameCodec#encode(String)}. Few examples: 214 * <ul> 215 * <li>Get a named property with fixed name: 216 * <pre> 217 * MethodHandle getColor = Boostrap.createDynamicInvoker( 218 * "color", 219 * NashornCallSiteDescriptor.GET_PROPERTY, 220 * Object.class, Object.class); 221 * Object obj = ...; // somehow obtain the object 222 * Object color = getColor.invokeExact(obj); 223 * </pre> 224 * </li> 225 * <li>Get a named property with variable name: 226 * <pre> 227 * MethodHandle getProperty = Boostrap.createDynamicInvoker( 228 * NameCodec.encode(""), 229 * NashornCallSiteDescriptor.GET_PROPERTY, 230 * Object.class, Object.class, String.class); 231 * Object obj = ...; // somehow obtain the object 232 * Object color = getProperty.invokeExact(obj, "color"); 233 * Object shape = getProperty.invokeExact(obj, "shape"); 234 * 235 * MethodHandle getNumProperty = Boostrap.createDynamicInvoker( 236 * NameCodec.encode(""), 237 * NashornCallSiteDescriptor.GET_ELEMENT, 238 * Object.class, Object.class, int.class); 239 * Object elem42 = getNumProperty.invokeExact(obj, 42); 240 * </pre> 241 * </li> 242 * <li>Set a named property with fixed name: 243 * <pre> 244 * MethodHandle setColor = Boostrap.createDynamicInvoker( 245 * "color", 246 * NashornCallSiteDescriptor.SET_PROPERTY, 247 * void.class, Object.class, Object.class); 248 * Object obj = ...; // somehow obtain the object 249 * setColor.invokeExact(obj, Color.BLUE); 250 * </pre> 251 * </li> 252 * <li>Set a property with variable name: 253 * <pre> 254 * MethodHandle setProperty = Boostrap.createDynamicInvoker( 255 * NameCodec.encode(""), 256 * NashornCallSiteDescriptor.SET_PROPERTY, 257 * void.class, Object.class, String.class, Object.class); 258 * Object obj = ...; // somehow obtain the object 259 * setProperty.invokeExact(obj, "color", Color.BLUE); 260 * setProperty.invokeExact(obj, "shape", Shape.CIRCLE); 261 * </pre> 262 * </li> 263 * <li>Call a function on an object; note it's a two-step process: get the 264 * method, then invoke the method. This is the actual: 265 * <pre> 266 * MethodHandle findFooFunction = Boostrap.createDynamicInvoker( 267 * "foo", 268 * NashornCallSiteDescriptor.GET_METHOD, 269 * Object.class, Object.class); 270 * Object obj = ...; // somehow obtain the object 271 * Object foo_fn = findFooFunction.invokeExact(obj); 272 * MethodHandle callFunctionWithTwoArgs = Boostrap.createDynamicCallInvoker( 273 * Object.class, Object.class, Object.class, Object.class, Object.class); 274 * // Note: "call" operation takes a function, then a "this" value, then the arguments: 275 * Object foo_retval = callFunctionWithTwoArgs.invokeExact(foo_fn, obj, arg1, arg2); 276 * </pre> 277 * </li> 278 * </ul> 279 * Few additional remarks: 280 * <ul> 281 * <li>Just as Nashorn works with any Java object, the invokers returned 282 * from this method can also be applied to arbitrary Java objects in 283 * addition to Nashorn JavaScript objects.</li> 284 * <li>For invoking a named function on an object, you can also use the 285 * {@link InvokeByName} convenience class.</li> 286 * <li>There's no rule that the variable property identifier has to be a 287 * {@code String} for {@code GET_PROPERTY/SET_PROPERTY} and {@code int} for 288 * {@code GET_ELEMENT/SET_ELEMENT}. You can declare their type to be 289 * {@code int}, {@code double}, {@code Object}, and so on regardless of the 290 * kind of the operation.</li> 291 * <li>You can be as specific in parameter types as you want. E.g. if you 292 * know that the receiver of the operation will always be 293 * {@code ScriptObject}, you can pass {@code ScriptObject.class} as its 294 * parameter type. If you happen to link to a method that expects different 295 * types, (you can use these invokers on POJOs too, after all, and end up 296 * linking with their methods that have strongly-typed signatures), all 297 * necessary conversions allowed by either Java or JavaScript will be 298 * applied: if invoked methods specify either primitive or wrapped Java 299 * numeric types, or {@code String} or {@code boolean/Boolean}, then the 300 * parameters might be subjected to standard ECMAScript {@code ToNumber}, 301 * {@code ToString}, and {@code ToBoolean} conversion, respectively. Less 302 * obviously, if the expected parameter type is a SAM type, and you pass a 303 * JavaScript function, a proxy object implementing the SAM type and 304 * delegating to the function will be passed. Linkage can often be optimized 305 * when linkers have more specific type information than "everything can be 306 * an object".</li> 307 * <li>You can also be as specific in return types as you want. For return 308 * types any necessary type conversion available in either Java or 309 * JavaScript will be automatically applied, similar to the process 310 * described for parameters, only in reverse direction: if you specify any 311 * either primitive or wrapped Java numeric type, or {@code String} or 312 * {@code boolean/Boolean}, then the return values will be subjected to 313 * standard ECMAScript {@code ToNumber}, {@code ToString}, and 314 * {@code ToBoolean} conversion, respectively. Less obviously, if the return 315 * type is a SAM type, and the return value is a JavaScript function, a 316 * proxy object implementing the SAM type and delegating to the function 317 * will be returned.</li> 318 * </ul> 319 * @param name name at the call site. Must not be null. Must be encoded 320 * using {@link NameCodec#encode(String)}. If the operation does not take a 321 * name, use empty string (also has to be encoded). 322 * @param flags the call site flags for the operation; see 323 * {@link NashornCallSiteDescriptor} for available flags. The most important 324 * part of the flags are the ones encoding the actual operation. 325 * @param rtype the return type for the operation 326 * @param ptypes the parameter types for the operation 327 * @return MethodHandle for invoking the operation. 328 */ 329 public static MethodHandle createDynamicInvoker(final String name, final int flags, final Class<?> rtype, final Class<?>... ptypes) { 330 return bootstrap(MethodHandles.publicLookup(), name, MethodType.methodType(rtype, ptypes), flags).dynamicInvoker(); 331 } 332 333 /** 334 * Returns a dynamic invoker for the {@link NashornCallSiteDescriptor#CALL} 335 * operation using the public lookup. 336 * @param rtype the return type for the operation 337 * @param ptypes the parameter types for the operation 338 * @return a dynamic invoker for the {@code CALL} operation. 339 */ 340 public static MethodHandle createDynamicCallInvoker(final Class<?> rtype, final Class<?>... ptypes) { 341 return createDynamicInvoker("", NashornCallSiteDescriptor.CALL, rtype, ptypes); 342 } 343 344 /** 345 * Returns a dynamic invoker for a specified dynamic operation using the 346 * public lookup. Similar to 347 * {@link #createDynamicInvoker(String, int, Class, Class...)} but with 348 * already precomposed method type. 349 * @param name name at the call site. 350 * @param flags flags at the call site 351 * @param type the method type for the operation 352 * @return MethodHandle for invoking the operation. 353 */ 354 public static MethodHandle createDynamicInvoker(final String name, final int flags, final MethodType type) { 355 return bootstrap(MethodHandles.publicLookup(), name, type, flags).dynamicInvoker(); 356 } 357 358 /** 359 * Binds any object Nashorn can use as a [[Callable]] to a receiver and optionally arguments. 360 * @param callable the callable to bind 361 * @param boundThis the bound "this" value. 362 * @param boundArgs the bound arguments. Can be either null or empty array to signify no arguments are bound. 363 * @return a bound callable. 364 * @throws ECMAException with {@code TypeError} if the object is not a callable. 365 */ 366 public static Object bindCallable(final Object callable, final Object boundThis, final Object[] boundArgs) { 367 if (callable instanceof ScriptFunction) { 368 return ((ScriptFunction)callable).createBound(boundThis, boundArgs); 369 } else if (callable instanceof BoundCallable) { 370 return ((BoundCallable)callable).bind(boundArgs); 371 } else if (isCallable(callable)) { 372 return new BoundCallable(callable, boundThis, boundArgs); 373 } 374 throw notFunction(callable); 375 } 376 377 /** 378 * Creates a super-adapter for an adapter, that is, an adapter to the adapter that allows invocation of superclass 379 * methods on it. 380 * @param adapter the original adapter 381 * @return a new adapter that can be used to invoke super methods on the original adapter. 382 */ 383 public static Object createSuperAdapter(final Object adapter) { 384 return new JavaSuperAdapter(adapter); 385 } 386 387 /** 388 * If the given class is a reflection-specific class (anything in {@code java.lang.reflect} and 389 * {@code java.lang.invoke} package, as well a {@link Class} and any subclass of {@link ClassLoader}) and there is 390 * a security manager in the system, then it checks the {@code nashorn.JavaReflection} {@code RuntimePermission}. 391 * @param clazz the class being tested 392 * @param isStatic is access checked for static members (or instance members) 393 */ 394 public static void checkReflectionAccess(final Class<?> clazz, final boolean isStatic) { 395 ReflectionCheckLinker.checkReflectionAccess(clazz, isStatic); 396 } 397 398 /** 399 * Returns the Nashorn's internally used dynamic linker's services object. Note that in code that is processing a 400 * linking request, you will normally use the {@code LinkerServices} object passed by whatever top-level linker 401 * invoked the linking (if the call site is in Nashorn-generated code, you'll get this object anyway). You should 402 * only resort to retrieving a linker services object using this method when you need some linker services (e.g. 403 * type converter method handles) outside of a code path that is linking a call site. 404 * @return Nashorn's internal dynamic linker's services object. 405 */ 406 public static LinkerServices getLinkerServices() { 407 return Context.getDynamicLinker().getLinkerServices(); 408 } 409 410 /** 411 * Takes a guarded invocation, and ensures its method and guard conform to the type of the call descriptor, using 412 * all type conversions allowed by the linker's services. This method is used by Nashorn's linkers as a last step 413 * before returning guarded invocations. Most of the code used to produce the guarded invocations does not make an 414 * effort to coordinate types of the methods, and so a final type adjustment before a guarded invocation is returned 415 * to the aggregating linker is the responsibility of the linkers themselves. 416 * @param inv the guarded invocation that needs to be type-converted. Can be null. 417 * @param linkerServices the linker services object providing the type conversions. 418 * @param desc the call site descriptor to whose method type the invocation needs to conform. 419 * @return the type-converted guarded invocation. If input is null, null is returned. If the input invocation 420 * already conforms to the requested type, it is returned unchanged. 421 */ 422 static GuardedInvocation asTypeSafeReturn(final GuardedInvocation inv, final LinkerServices linkerServices, final CallSiteDescriptor desc) { 423 return inv == null ? null : inv.asTypeSafeReturn(linkerServices, desc.getMethodType()); 424 } 425 426 /** 427 * Adapts the return type of the method handle with {@code explicitCastArguments} when it is an unboxing 428 * conversion. This will ensure that nulls are unwrapped to false or 0. 429 * @param target the target method handle 430 * @param newType the desired new type. Note that this method does not adapt the method handle completely to the 431 * new type, it only adapts the return type; this is allowed as per 432 * {@link DynamicLinkerFactory#setAutoConversionStrategy(MethodTypeConversionStrategy)}, which is what this method 433 * is used for. 434 * @return the method handle with adapted return type, if it required an unboxing conversion. 435 */ 436 private static MethodHandle unboxReturnType(final MethodHandle target, final MethodType newType) { 437 final MethodType targetType = target.type(); 438 final Class<?> oldReturnType = targetType.returnType(); 439 final Class<?> newReturnType = newType.returnType(); 440 if (TypeUtilities.isWrapperType(oldReturnType)) { 441 if (newReturnType.isPrimitive()) { 442 // The contract of setAutoConversionStrategy is such that the difference between newType and targetType 443 // can only be JLS method invocation conversions. 444 assert TypeUtilities.isMethodInvocationConvertible(oldReturnType, newReturnType); 445 return MethodHandles.explicitCastArguments(target, targetType.changeReturnType(newReturnType)); 446 } 447 } else if (oldReturnType == void.class && newReturnType == Object.class) { 448 return MethodHandles.filterReturnValue(target, VOID_TO_OBJECT); 449 } 450 return target; 451 } 452 453 private static MethodHandle createMissingMemberHandler( 454 final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception { 455 if (BrowserJSObjectLinker.canLinkTypeStatic(linkRequest.getReceiver().getClass())) { 456 // Don't create missing member handlers for the browser JS objects as they 457 // have their own logic. 458 return null; 459 } 460 return NashornBottomLinker.linkMissingBeanMember(linkRequest, linkerServices); 461 } 462} 463