Mon, 03 Nov 2014 09:49:52 +0100
8059443: NPE when unboxing return values
Reviewed-by: lagergren, sundar
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
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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
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24 */
26 /*
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file, and Oracle licenses the original version of this file under the BSD
31 * license:
32 */
33 /*
34 Copyright 2009-2013 Attila Szegedi
36 Licensed under both the Apache License, Version 2.0 (the "Apache License")
37 and the BSD License (the "BSD License"), with licensee being free to
38 choose either of the two at their discretion.
40 You may not use this file except in compliance with either the Apache
41 License or the BSD License.
43 If you choose to use this file in compliance with the Apache License, the
44 following notice applies to you:
46 You may obtain a copy of the Apache License at
48 http://www.apache.org/licenses/LICENSE-2.0
50 Unless required by applicable law or agreed to in writing, software
51 distributed under the License is distributed on an "AS IS" BASIS,
52 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
53 implied. See the License for the specific language governing
54 permissions and limitations under the License.
56 If you choose to use this file in compliance with the BSD License, the
57 following notice applies to you:
59 Redistribution and use in source and binary forms, with or without
60 modification, are permitted provided that the following conditions are
61 met:
62 * Redistributions of source code must retain the above copyright
63 notice, this list of conditions and the following disclaimer.
64 * Redistributions in binary form must reproduce the above copyright
65 notice, this list of conditions and the following disclaimer in the
66 documentation and/or other materials provided with the distribution.
67 * Neither the name of the copyright holder nor the names of
68 contributors may be used to endorse or promote products derived from
69 this software without specific prior written permission.
71 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
72 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
73 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
74 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
75 BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
76 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
77 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
78 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
79 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
80 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
81 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
82 */
84 package jdk.internal.dynalink;
86 import java.lang.invoke.MutableCallSite;
87 import java.security.AccessController;
88 import java.security.PrivilegedAction;
89 import java.util.ArrayList;
90 import java.util.Arrays;
91 import java.util.Collections;
92 import java.util.HashSet;
93 import java.util.LinkedList;
94 import java.util.List;
95 import java.util.Set;
96 import jdk.internal.dynalink.beans.BeansLinker;
97 import jdk.internal.dynalink.linker.GuardingDynamicLinker;
98 import jdk.internal.dynalink.linker.GuardingTypeConverterFactory;
99 import jdk.internal.dynalink.linker.LinkRequest;
100 import jdk.internal.dynalink.linker.MethodTypeConversionStrategy;
101 import jdk.internal.dynalink.support.AutoDiscovery;
102 import jdk.internal.dynalink.support.BottomGuardingDynamicLinker;
103 import jdk.internal.dynalink.support.ClassLoaderGetterContextProvider;
104 import jdk.internal.dynalink.support.CompositeGuardingDynamicLinker;
105 import jdk.internal.dynalink.support.CompositeTypeBasedGuardingDynamicLinker;
106 import jdk.internal.dynalink.support.DefaultPrelinkFilter;
107 import jdk.internal.dynalink.support.LinkerServicesImpl;
108 import jdk.internal.dynalink.support.TypeConverterFactory;
109 import jdk.internal.dynalink.support.TypeUtilities;
111 /**
112 * A factory class for creating {@link DynamicLinker}s. The most usual dynamic linker is a linker that is a composition
113 * of all {@link GuardingDynamicLinker}s known and pre-created by the caller as well as any
114 * {@link AutoDiscovery automatically discovered} guarding linkers and the standard fallback {@link BeansLinker} and a
115 * {@link DefaultPrelinkFilter}. See {@link DynamicLinker} documentation for tips on how to use this class.
116 *
117 * @author Attila Szegedi
118 */
119 public class DynamicLinkerFactory {
120 /**
121 * Default value for {@link #setUnstableRelinkThreshold(int) unstable relink threshold}.
122 */
123 public static final int DEFAULT_UNSTABLE_RELINK_THRESHOLD = 8;
125 private boolean classLoaderExplicitlySet = false;
126 private ClassLoader classLoader;
128 private List<? extends GuardingDynamicLinker> prioritizedLinkers;
129 private List<? extends GuardingDynamicLinker> fallbackLinkers;
130 private int runtimeContextArgCount = 0;
131 private boolean syncOnRelink = false;
132 private int unstableRelinkThreshold = DEFAULT_UNSTABLE_RELINK_THRESHOLD;
133 private GuardedInvocationFilter prelinkFilter;
134 private MethodTypeConversionStrategy autoConversionStrategy;
136 /**
137 * Sets the class loader for automatic discovery of available linkers. If not set explicitly, then the thread
138 * context class loader at the time of {@link #createLinker()} invocation will be used.
139 *
140 * @param classLoader the class loader used for the autodiscovery of available linkers.
141 */
142 public void setClassLoader(final ClassLoader classLoader) {
143 this.classLoader = classLoader;
144 classLoaderExplicitlySet = true;
145 }
147 /**
148 * Sets the prioritized linkers. Language runtimes using this framework will usually precreate at least the linker
149 * for their own language. These linkers will be consulted first in the resulting dynamic linker, before any
150 * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the prioritized
151 * linkers, it will be ignored and the explicit prioritized instance will be used.
152 *
153 * @param prioritizedLinkers the list of prioritized linkers. Null can be passed to indicate no prioritized linkers
154 * (this is also the default value).
155 */
156 public void setPrioritizedLinkers(final List<? extends GuardingDynamicLinker> prioritizedLinkers) {
157 this.prioritizedLinkers =
158 prioritizedLinkers == null ? null : new ArrayList<>(prioritizedLinkers);
159 }
161 /**
162 * Sets the prioritized linkers. Language runtimes using this framework will usually precreate at least the linker
163 * for their own language. These linkers will be consulted first in the resulting dynamic linker, before any
164 * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the prioritized
165 * linkers, it will be ignored and the explicit prioritized instance will be used.
166 *
167 * @param prioritizedLinkers a list of prioritized linkers.
168 */
169 public void setPrioritizedLinkers(final GuardingDynamicLinker... prioritizedLinkers) {
170 setPrioritizedLinkers(Arrays.asList(prioritizedLinkers));
171 }
173 /**
174 * Sets a single prioritized linker. Identical to calling {@link #setPrioritizedLinkers(List)} with a single-element
175 * list.
176 *
177 * @param prioritizedLinker the single prioritized linker. Must not be null.
178 * @throws IllegalArgumentException if null is passed.
179 */
180 public void setPrioritizedLinker(final GuardingDynamicLinker prioritizedLinker) {
181 if(prioritizedLinker == null) {
182 throw new IllegalArgumentException("prioritizedLinker == null");
183 }
184 this.prioritizedLinkers = Collections.singletonList(prioritizedLinker);
185 }
187 /**
188 * Sets the fallback linkers. These linkers will be consulted last in the resulting composite linker, after any
189 * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the fallback
190 * linkers, it will be ignored and the explicit fallback instance will be used.
191 *
192 * @param fallbackLinkers the list of fallback linkers. Can be empty to indicate the caller wishes to set no
193 * fallback linkers.
194 */
195 public void setFallbackLinkers(final List<? extends GuardingDynamicLinker> fallbackLinkers) {
196 this.fallbackLinkers = fallbackLinkers == null ? null : new ArrayList<>(fallbackLinkers);
197 }
199 /**
200 * Sets the fallback linkers. These linkers will be consulted last in the resulting composite linker, after any
201 * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the fallback
202 * linkers, it will be ignored and the explicit fallback instance will be used.
203 *
204 * @param fallbackLinkers the list of fallback linkers. Can be empty to indicate the caller wishes to set no
205 * fallback linkers. If it is left as null, the standard fallback {@link BeansLinker} will be used.
206 */
207 public void setFallbackLinkers(final GuardingDynamicLinker... fallbackLinkers) {
208 setFallbackLinkers(Arrays.asList(fallbackLinkers));
209 }
211 /**
212 * Sets the number of arguments in the call sites that represent the stack context of the language runtime creating
213 * the linker. If the language runtime uses no context information passed on stack, then it should be zero
214 * (the default value). If it is set to nonzero value, then every dynamic call site emitted by this runtime must
215 * have the argument list of the form: {@code (this, contextArg1[, contextArg2[, ...]], normalArgs)}. It is
216 * advisable to only pass one context-specific argument, though, of an easily recognizable, runtime specific type
217 * encapsulating the runtime thread local state.
218 *
219 * @param runtimeContextArgCount the number of language runtime context arguments in call sites.
220 */
221 public void setRuntimeContextArgCount(final int runtimeContextArgCount) {
222 if(runtimeContextArgCount < 0) {
223 throw new IllegalArgumentException("runtimeContextArgCount < 0");
224 }
225 this.runtimeContextArgCount = runtimeContextArgCount;
226 }
228 /**
229 * Sets whether the linker created by this factory will invoke {@link MutableCallSite#syncAll(MutableCallSite[])}
230 * after a call site is relinked. Defaults to false. You probably want to set it to true if your runtime supports
231 * multithreaded execution of dynamically linked code.
232 * @param syncOnRelink true for invoking sync on relink, false otherwise.
233 */
234 public void setSyncOnRelink(final boolean syncOnRelink) {
235 this.syncOnRelink = syncOnRelink;
236 }
238 /**
239 * Sets the unstable relink threshold; the number of times a call site is relinked after which it will be
240 * considered unstable, and subsequent link requests for it will indicate this.
241 * @param unstableRelinkThreshold the new threshold. Must not be less than zero. The value of zero means that
242 * call sites will never be considered unstable.
243 * @see LinkRequest#isCallSiteUnstable()
244 */
245 public void setUnstableRelinkThreshold(final int unstableRelinkThreshold) {
246 if(unstableRelinkThreshold < 0) {
247 throw new IllegalArgumentException("unstableRelinkThreshold < 0");
248 }
249 this.unstableRelinkThreshold = unstableRelinkThreshold;
250 }
252 /**
253 * Set the pre-link filter. This is a {@link GuardedInvocationFilter} that will get the final chance to modify the
254 * guarded invocation after it has been created by a component linker and before the dynamic linker links it into
255 * the call site. It is normally used to adapt the return value type of the invocation to the type of the call site.
256 * When not set explicitly, {@link DefaultPrelinkFilter} will be used.
257 * @param prelinkFilter the pre-link filter for the dynamic linker.
258 */
259 public void setPrelinkFilter(final GuardedInvocationFilter prelinkFilter) {
260 this.prelinkFilter = prelinkFilter;
261 }
263 /**
264 * Sets an object representing the conversion strategy for automatic type conversions. After
265 * {@link TypeConverterFactory#asType(java.lang.invoke.MethodHandle, java.lang.invoke.MethodType)} has
266 * applied all custom conversions to a method handle, it still needs to effect
267 * {@link TypeUtilities#isMethodInvocationConvertible(Class, Class) method invocation conversions} that
268 * can usually be automatically applied as per
269 * {@link java.lang.invoke.MethodHandle#asType(java.lang.invoke.MethodType)}.
270 * However, sometimes language runtimes will want to customize even those conversions for their own call
271 * sites. A typical example is allowing unboxing of null return values, which is by default prohibited by
272 * ordinary {@code MethodHandles.asType}. In this case, a language runtime can install its own custom
273 * automatic conversion strategy, that can deal with null values. Note that when the strategy's
274 * {@link MethodTypeConversionStrategy#asType(java.lang.invoke.MethodHandle, java.lang.invoke.MethodType)}
275 * is invoked, the custom language conversions will already have been applied to the method handle, so by
276 * design the difference between the handle's current method type and the desired final type will always
277 * only be ones that can be subjected to method invocation conversions. The strategy also doesn't need to
278 * invoke a final {@code MethodHandle.asType()} as the converter factory will do that as the final step.
279 * @param autoConversionStrategy the strategy for applying method invocation conversions for the linker
280 * created by this factory.
281 */
282 public void setAutoConversionStrategy(final MethodTypeConversionStrategy autoConversionStrategy) {
283 this.autoConversionStrategy = autoConversionStrategy;
284 }
286 /**
287 * Creates a new dynamic linker consisting of all the prioritized, autodiscovered, and fallback linkers as well as
288 * the pre-link filter.
289 *
290 * @return the new dynamic Linker
291 */
292 public DynamicLinker createLinker() {
293 // Treat nulls appropriately
294 if(prioritizedLinkers == null) {
295 prioritizedLinkers = Collections.emptyList();
296 }
297 if(fallbackLinkers == null) {
298 fallbackLinkers = Collections.singletonList(new BeansLinker());
299 }
301 // Gather classes of all precreated (prioritized and fallback) linkers.
302 // We'll filter out any discovered linkers of the same class.
303 final Set<Class<? extends GuardingDynamicLinker>> knownLinkerClasses =
304 new HashSet<>();
305 addClasses(knownLinkerClasses, prioritizedLinkers);
306 addClasses(knownLinkerClasses, fallbackLinkers);
308 final ClassLoader effectiveClassLoader = classLoaderExplicitlySet ? classLoader : getThreadContextClassLoader();
309 final List<GuardingDynamicLinker> discovered = AutoDiscovery.loadLinkers(effectiveClassLoader);
310 // Now, concatenate ...
311 final List<GuardingDynamicLinker> linkers =
312 new ArrayList<>(prioritizedLinkers.size() + discovered.size()
313 + fallbackLinkers.size());
314 // ... prioritized linkers, ...
315 linkers.addAll(prioritizedLinkers);
316 // ... filtered discovered linkers, ...
317 for(final GuardingDynamicLinker linker: discovered) {
318 if(!knownLinkerClasses.contains(linker.getClass())) {
319 linkers.add(linker);
320 }
321 }
322 // ... and finally fallback linkers.
323 linkers.addAll(fallbackLinkers);
324 final List<GuardingDynamicLinker> optimized = CompositeTypeBasedGuardingDynamicLinker.optimize(linkers);
325 final GuardingDynamicLinker composite;
326 switch(linkers.size()) {
327 case 0: {
328 composite = BottomGuardingDynamicLinker.INSTANCE;
329 break;
330 }
331 case 1: {
332 composite = optimized.get(0);
333 break;
334 }
335 default: {
336 composite = new CompositeGuardingDynamicLinker(optimized);
337 break;
338 }
339 }
341 final List<GuardingTypeConverterFactory> typeConverters = new LinkedList<>();
342 for(final GuardingDynamicLinker linker: linkers) {
343 if(linker instanceof GuardingTypeConverterFactory) {
344 typeConverters.add((GuardingTypeConverterFactory)linker);
345 }
346 }
348 if(prelinkFilter == null) {
349 prelinkFilter = new DefaultPrelinkFilter();
350 }
352 return new DynamicLinker(new LinkerServicesImpl(new TypeConverterFactory(typeConverters,
353 autoConversionStrategy), composite), prelinkFilter, runtimeContextArgCount, syncOnRelink,
354 unstableRelinkThreshold);
355 }
357 private static ClassLoader getThreadContextClassLoader() {
358 return AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
359 @Override
360 public ClassLoader run() {
361 return Thread.currentThread().getContextClassLoader();
362 }
363 }, ClassLoaderGetterContextProvider.GET_CLASS_LOADER_CONTEXT);
364 }
366 private static void addClasses(final Set<Class<? extends GuardingDynamicLinker>> knownLinkerClasses,
367 final List<? extends GuardingDynamicLinker> linkers) {
368 for(final GuardingDynamicLinker linker: linkers) {
369 knownLinkerClasses.add(linker.getClass());
370 }
371 }
372 }