1 /* 2 * Copyright (c) 2016, 2018, 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 package jdk.internal.org.objectweb.asm; 25 26 import java.lang.reflect.InaccessibleObjectException; 27 28 public class ClassWriterExt extends ClassWriter { 29 private boolean cacheInvokeDynamic = true; 30 private boolean cacheMTypes = true; 31 private boolean cacheMHandles = true; 32 33 private final Item key = new Item(); 34 35 public ClassWriterExt(ClassReader cr, int flags) { 36 super(cr, flags); 37 } 38 39 public ClassWriterExt(int flags) { 40 super(flags); 41 } 42 43 @Override 44 Item newInvokeDynamicItem(final String name, final String desc, 45 final Handle bsm, final Object... bsmArgs) { 46 if (cacheInvokeDynamic) { 47 return super.newInvokeDynamicItem(name, desc, bsm, bsmArgs); 48 } 49 int type = ClassWriter.INDY; 50 disableItemHashTableFor(type); 51 Item result; 52 try { 53 return super.newInvokeDynamicItem(name, desc, bsm, bsmArgs); 54 } finally { 55 restoreItemHashTableFor(type); 56 } 57 } 58 59 @Override 60 Item newStringishItem(final int type, final String value) { 61 if (type != ClassWriter.MTYPE) { 62 return super.newStringishItem(type, value); 63 } 64 if (cacheMTypes) { 65 return super.newStringishItem(type, value); 66 } 67 disableItemHashTableFor(type); 68 try { 69 return super.newStringishItem(type, value); 70 } finally { 71 restoreItemHashTableFor(type); 72 } 73 } 74 75 @Override 76 Item newHandleItem(final int tag, final String owner, final String name, 77 final String desc, final boolean itf) { 78 if (cacheMHandles) { 79 return super.newHandleItem(tag, owner, name, desc, itf); 80 } 81 int type = ClassWriter.HANDLE_BASE + tag; 82 disableItemHashTableFor(type); 83 try { 84 return super.newHandleItem(tag, owner, name, desc, itf); 85 } finally { 86 restoreItemHashTableFor(type); 87 } 88 } 89 90 private void disableItemHashTableFor(int type) { 91 for (Item i : items) { 92 while (i != null) { 93 if (i.type == type) { 94 i.type = -type; 95 } 96 i = i.next; 97 } 98 } 99 } 100 101 private void restoreItemHashTableFor(int type) { 102 for (Item i : items) { 103 while (i != null) { 104 if (i.type == -type) { 105 i.type = type; 106 } 107 i = i.next; 108 } 109 } 110 } 111 112 public void setCacheInvokeDynamic(boolean value) { 113 cacheInvokeDynamic = value; 114 } 115 public void setCacheMTypes(boolean value) { 116 cacheMTypes = value; 117 } 118 public void setCacheMHandles(boolean value) { 119 cacheMHandles = value; 120 } 121 122 public int getBytecodeLength(MethodVisitor mv) { 123 ByteVector code; 124 try { 125 java.lang.reflect.Field field = mv.getClass().getDeclaredField("code"); 126 field.setAccessible(true); 127 code = (ByteVector) field.get(mv); 128 } catch (InaccessibleObjectException | SecurityException | ReflectiveOperationException e) { 129 throw new Error("can not read field 'code' from class " + mv.getClass(), e); 130 } 131 try { 132 java.lang.reflect.Field field = code.getClass().getDeclaredField("length"); 133 field.setAccessible(true); 134 return field.getInt(code); 135 } catch (InaccessibleObjectException | SecurityException | ReflectiveOperationException e) { 136 throw new Error("can not read field 'length' from class " + code.getClass(), e); 137 } 138 } 139 } 140