Mon, 12 Aug 2013 12:46:01 +0200
8022789: Revisit doPrivileged blocks in Dynalink
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
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 */
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.support.AutoDiscovery;
101 import jdk.internal.dynalink.support.BottomGuardingDynamicLinker;
102 import jdk.internal.dynalink.support.ClassLoaderGetterContextProvider;
103 import jdk.internal.dynalink.support.CompositeGuardingDynamicLinker;
104 import jdk.internal.dynalink.support.CompositeTypeBasedGuardingDynamicLinker;
105 import jdk.internal.dynalink.support.LinkerServicesImpl;
106 import jdk.internal.dynalink.support.TypeConverterFactory;
108 /**
109 * A factory class for creating {@link DynamicLinker}s. The most usual dynamic linker is a linker that is a composition
110 * of all {@link GuardingDynamicLinker}s known and pre-created by the caller as well as any
111 * {@link AutoDiscovery automatically discovered} guarding linkers and the standard fallback {@link BeansLinker}. See
112 * {@link DynamicLinker} documentation for tips on how to use this class.
113 *
114 * @author Attila Szegedi
115 */
116 public class DynamicLinkerFactory {
118 /**
119 * Default value for {@link #setUnstableRelinkThreshold(int) unstable relink threshold}.
120 */
121 public static final int DEFAULT_UNSTABLE_RELINK_THRESHOLD = 8;
123 private boolean classLoaderExplicitlySet = false;
124 private ClassLoader classLoader;
126 private List<? extends GuardingDynamicLinker> prioritizedLinkers;
127 private List<? extends GuardingDynamicLinker> fallbackLinkers;
128 private int runtimeContextArgCount = 0;
129 private boolean syncOnRelink = false;
130 private int unstableRelinkThreshold = DEFAULT_UNSTABLE_RELINK_THRESHOLD;
132 /**
133 * Sets the class loader for automatic discovery of available linkers. If not set explicitly, then the thread
134 * context class loader at the time of {@link #createLinker()} invocation will be used.
135 *
136 * @param classLoader the class loader used for the autodiscovery of available linkers.
137 */
138 public void setClassLoader(ClassLoader classLoader) {
139 this.classLoader = classLoader;
140 classLoaderExplicitlySet = true;
141 }
143 /**
144 * Sets the prioritized linkers. Language runtimes using this framework will usually precreate at least the linker
145 * for their own language. These linkers will be consulted first in the resulting dynamic linker, before any
146 * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the prioritized
147 * linkers, it will be ignored and the explicit prioritized instance will be used.
148 *
149 * @param prioritizedLinkers the list of prioritized linkers. Null can be passed to indicate no prioritized linkers
150 * (this is also the default value).
151 */
152 public void setPrioritizedLinkers(List<? extends GuardingDynamicLinker> prioritizedLinkers) {
153 this.prioritizedLinkers =
154 prioritizedLinkers == null ? null : new ArrayList<>(prioritizedLinkers);
155 }
157 /**
158 * Sets the prioritized linkers. Language runtimes using this framework will usually precreate at least the linker
159 * for their own language. These linkers will be consulted first in the resulting dynamic linker, before any
160 * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the prioritized
161 * linkers, it will be ignored and the explicit prioritized instance will be used.
162 *
163 * @param prioritizedLinkers a list of prioritized linkers.
164 */
165 public void setPrioritizedLinkers(GuardingDynamicLinker... prioritizedLinkers) {
166 setPrioritizedLinkers(Arrays.asList(prioritizedLinkers));
167 }
169 /**
170 * Sets a single prioritized linker. Identical to calling {@link #setPrioritizedLinkers(List)} with a single-element
171 * list.
172 *
173 * @param prioritizedLinker the single prioritized linker. Must not be null.
174 * @throws IllegalArgumentException if null is passed.
175 */
176 public void setPrioritizedLinker(GuardingDynamicLinker prioritizedLinker) {
177 if(prioritizedLinker == null) {
178 throw new IllegalArgumentException("prioritizedLinker == null");
179 }
180 this.prioritizedLinkers = Collections.singletonList(prioritizedLinker);
181 }
183 /**
184 * Sets the fallback linkers. These linkers will be consulted last in the resulting composite linker, after any
185 * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the fallback
186 * linkers, it will be ignored and the explicit fallback instance will be used.
187 *
188 * @param fallbackLinkers the list of fallback linkers. Can be empty to indicate the caller wishes to set no
189 * fallback linkers.
190 */
191 public void setFallbackLinkers(List<? extends GuardingDynamicLinker> fallbackLinkers) {
192 this.fallbackLinkers = fallbackLinkers == null ? null : new ArrayList<>(fallbackLinkers);
193 }
195 /**
196 * Sets the fallback linkers. These linkers will be consulted last in the resulting composite linker, after any
197 * autodiscovered linkers. If the framework also autodiscovers a linker of the same class as one of the fallback
198 * linkers, it will be ignored and the explicit fallback instance will be used.
199 *
200 * @param fallbackLinkers the list of fallback linkers. Can be empty to indicate the caller wishes to set no
201 * fallback linkers. If it is left as null, the standard fallback {@link BeansLinker} will be used.
202 */
203 public void setFallbackLinkers(GuardingDynamicLinker... fallbackLinkers) {
204 setFallbackLinkers(Arrays.asList(fallbackLinkers));
205 }
207 /**
208 * Sets the number of arguments in the call sites that represent the stack context of the language runtime creating
209 * the linker. If the language runtime uses no context information passed on stack, then it should be zero
210 * (the default value). If it is set to nonzero value, then every dynamic call site emitted by this runtime must
211 * have the argument list of the form: {@code (this, contextArg1[, contextArg2[, ...]], normalArgs)}. It is
212 * advisable to only pass one context-specific argument, though, of an easily recognizable, runtime specific type
213 * encapsulating the runtime thread local state.
214 *
215 * @param runtimeContextArgCount the number of language runtime context arguments in call sites.
216 */
217 public void setRuntimeContextArgCount(int runtimeContextArgCount) {
218 if(runtimeContextArgCount < 0) {
219 throw new IllegalArgumentException("runtimeContextArgCount < 0");
220 }
221 this.runtimeContextArgCount = runtimeContextArgCount;
222 }
224 /**
225 * Sets whether the linker created by this factory will invoke {@link MutableCallSite#syncAll(MutableCallSite[])}
226 * after a call site is relinked. Defaults to false. You probably want to set it to true if your runtime supports
227 * multithreaded execution of dynamically linked code.
228 * @param syncOnRelink true for invoking sync on relink, false otherwise.
229 */
230 public void setSyncOnRelink(boolean syncOnRelink) {
231 this.syncOnRelink = syncOnRelink;
232 }
234 /**
235 * Sets the unstable relink threshold; the number of times a call site is relinked after which it will be
236 * considered unstable, and subsequent link requests for it will indicate this.
237 * @param unstableRelinkThreshold the new threshold. Must not be less than zero. The value of zero means that
238 * call sites will never be considered unstable.
239 * @see LinkRequest#isCallSiteUnstable()
240 */
241 public void setUnstableRelinkThreshold(int unstableRelinkThreshold) {
242 if(unstableRelinkThreshold < 0) {
243 throw new IllegalArgumentException("unstableRelinkThreshold < 0");
244 }
245 this.unstableRelinkThreshold = unstableRelinkThreshold;
246 }
248 /**
249 * Creates a new dynamic linker consisting of all the prioritized, autodiscovered, and fallback linkers.
250 *
251 * @return the new dynamic Linker
252 */
253 public DynamicLinker createLinker() {
254 // Treat nulls appropriately
255 if(prioritizedLinkers == null) {
256 prioritizedLinkers = Collections.emptyList();
257 }
258 if(fallbackLinkers == null) {
259 fallbackLinkers = Collections.singletonList(new BeansLinker());
260 }
262 // Gather classes of all precreated (prioritized and fallback) linkers.
263 // We'll filter out any discovered linkers of the same class.
264 final Set<Class<? extends GuardingDynamicLinker>> knownLinkerClasses =
265 new HashSet<>();
266 addClasses(knownLinkerClasses, prioritizedLinkers);
267 addClasses(knownLinkerClasses, fallbackLinkers);
269 final ClassLoader effectiveClassLoader = classLoaderExplicitlySet ? classLoader : getThreadContextClassLoader();
270 final List<GuardingDynamicLinker> discovered = AutoDiscovery.loadLinkers(effectiveClassLoader);
271 // Now, concatenate ...
272 final List<GuardingDynamicLinker> linkers =
273 new ArrayList<>(prioritizedLinkers.size() + discovered.size()
274 + fallbackLinkers.size());
275 // ... prioritized linkers, ...
276 linkers.addAll(prioritizedLinkers);
277 // ... filtered discovered linkers, ...
278 for(GuardingDynamicLinker linker: discovered) {
279 if(!knownLinkerClasses.contains(linker.getClass())) {
280 linkers.add(linker);
281 }
282 }
283 // ... and finally fallback linkers.
284 linkers.addAll(fallbackLinkers);
285 final List<GuardingDynamicLinker> optimized = CompositeTypeBasedGuardingDynamicLinker.optimize(linkers);
286 final GuardingDynamicLinker composite;
287 switch(linkers.size()) {
288 case 0: {
289 composite = BottomGuardingDynamicLinker.INSTANCE;
290 break;
291 }
292 case 1: {
293 composite = optimized.get(0);
294 break;
295 }
296 default: {
297 composite = new CompositeGuardingDynamicLinker(optimized);
298 break;
299 }
300 }
302 final List<GuardingTypeConverterFactory> typeConverters = new LinkedList<>();
303 for(GuardingDynamicLinker linker: linkers) {
304 if(linker instanceof GuardingTypeConverterFactory) {
305 typeConverters.add((GuardingTypeConverterFactory)linker);
306 }
307 }
309 return new DynamicLinker(new LinkerServicesImpl(new TypeConverterFactory(typeConverters), composite),
310 runtimeContextArgCount, syncOnRelink, unstableRelinkThreshold);
311 }
313 private static ClassLoader getThreadContextClassLoader() {
314 return AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
315 @Override
316 public ClassLoader run() {
317 return Thread.currentThread().getContextClassLoader();
318 }
319 }, ClassLoaderGetterContextProvider.GET_CLASS_LOADER_CONTEXT);
320 }
322 private static void addClasses(Set<Class<? extends GuardingDynamicLinker>> knownLinkerClasses,
323 List<? extends GuardingDynamicLinker> linkers) {
324 for(GuardingDynamicLinker linker: linkers) {
325 knownLinkerClasses.add(linker.getClass());
326 }
327 }
328 }