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src/java.base/share/classes/jdk/internal/reflect/NativeMethodAccessorImpl.java

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  1 /*
  2  * Copyright (c) 2001, 2021, 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 
 26 package jdk.internal.reflect;
 27 
 28 import java.lang.reflect.*;

 29 import jdk.internal.misc.Unsafe;

 30 
 31 /** Used only for the first few invocations of a Method; afterward,
 32     switches to bytecode-based implementation */
 33 
 34 class NativeMethodAccessorImpl extends MethodAccessorImpl {
 35      private static final Unsafe U = Unsafe.getUnsafe();
 36      private static final long GENERATED_OFFSET
 37         = U.objectFieldOffset(NativeMethodAccessorImpl.class, "generated");
 38 
 39     private final Method method;
 40     private final DelegatingMethodAccessorImpl parent;
 41     private int numInvocations;
 42     private volatile int generated;
 43 
 44     NativeMethodAccessorImpl(Method method) {
 45         this.method = method;
 46         this.parent = new DelegatingMethodAccessorImpl(this);
 47     }
 48 
 49     public Object invoke(Object obj, Object[] args)
 50         throws IllegalArgumentException, InvocationTargetException
 51     {
 52         // We can't inflate methods belonging to vm-anonymous classes because
 53         // that kind of class can't be referred to by name, hence can't be
 54         // found from the generated bytecode.
 55         if (++numInvocations > ReflectionFactory.inflationThreshold()
 56                 && !method.getDeclaringClass().isHidden()
 57                 && generated == 0
 58                 && U.compareAndSetInt(this, GENERATED_OFFSET, 0, 1)) {













 59             try {
 60                 MethodAccessorImpl acc = (MethodAccessorImpl)
 61                     new MethodAccessorGenerator().
 62                         generateMethod(method.getDeclaringClass(),
 63                                        method.getName(),
 64                                        method.getParameterTypes(),
 65                                        method.getReturnType(),
 66                                        method.getExceptionTypes(),
 67                                        method.getModifiers());
 68                 parent.setDelegate(acc);



 69             } catch (Throwable t) {
 70                 // Throwable happens in generateMethod, restore generated to 0
 71                 generated = 0;
 72                 throw t;
 73             }



 74         }
 75 
 76         return invoke0(method, obj, args);
 77     }
 78 
 79     DelegatingMethodAccessorImpl getParent() {
 80         return parent;
 81     }
 82 
 83     private static native Object invoke0(Method m, Object obj, Object[] args);
 84 }

  1 /*
  2  * Copyright (c) 2001, 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  */
 25 
 26 package jdk.internal.reflect;
 27 
 28 import java.lang.reflect.InvocationTargetException;
 29 import java.lang.reflect.Method;
 30 import jdk.internal.misc.Unsafe;
 31 import sun.reflect.misc.ReflectUtil;
 32 
 33 /** Used only for the first few invocations of a Method; afterward,
 34     switches to bytecode-based implementation */
 35 
 36 class NativeMethodAccessorImpl extends MethodAccessorImpl {
 37     private static final Unsafe U = Unsafe.getUnsafe();
 38     private static final long GENERATED_OFFSET
 39         = U.objectFieldOffset(NativeMethodAccessorImpl.class, "generated");
 40 
 41     private final Method method;
 42     private final DelegatingMethodAccessorImpl parent;
 43     private int numInvocations;
 44     private volatile int generated;
 45 
 46     NativeMethodAccessorImpl(Method method) {
 47         this.method = method;
 48         this.parent = new DelegatingMethodAccessorImpl(this);
 49     }
 50 
 51     public Object invoke(Object obj, Object[] args)
 52         throws IllegalArgumentException, InvocationTargetException
 53     {
 54         boolean generate = false;
 55         if (!method.getDeclaringClass().isHidden()) {
 56             if (Thread.currentThread().isVirtual()) {
 57                 generate = true;
 58             } else {
 59                 if (++numInvocations > ReflectionFactory.inflationThreshold()
 60                         && generated == 0
 61                         && U.compareAndSetInt(this, GENERATED_OFFSET, 0, 1)) {
 62                     generate = true;
 63                 }
 64             }
 65         }
 66 
 67         if (generate) {
 68             Class<?> declaringClass = method.getDeclaringClass();
 69 
 70             // class initializer may not have run
 71             Unsafe.getUnsafe().ensureClassInitialized(declaringClass);
 72 
 73             MethodAccessorImpl acc;
 74             try {
 75                 // use bytecode generated implementation for @CS methods for now
 76                 if (Reflection.isCallerSensitive(method)) {
 77                     acc = (MethodAccessorImpl) new MethodAccessorGenerator()
 78                                 .generateMethod(declaringClass,
 79                                                 method.getName(),
 80                                                 method.getParameterTypes(),
 81                                                 method.getReturnType(),
 82                                                 method.getExceptionTypes(),
 83                                                 method.getModifiers());
 84                 } else {
 85                     acc = NewAccessorImplFactory.newMethodAccessorImpl(method);
 86                 }
 87             } catch (Throwable t) {
 88                 // generateMethod failed, restore generated to 0
 89                 generated = 0;
 90                 throw t;
 91             }
 92 
 93             parent.setDelegate(acc);
 94             return acc.invoke(obj, args);
 95         }
 96 
 97         return invoke0(method, obj, args);
 98     }
 99 
100     DelegatingMethodAccessorImpl getParent() {
101         return parent;
102     }
103 
104     private static native Object invoke0(Method m, Object obj, Object[] args);
105 }
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