1 /*
   2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.  Oracle designates this
   7  * particular file as subject to the "Classpath" exception as provided
   8  * by Oracle in the LICENSE file that accompanied this code.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  */
  24 
  25 /*
  26  * This file is available under and governed by the GNU General Public
  27  * License version 2 only, as published by the Free Software Foundation.
  28  * However, the following notice accompanied the original version of this
  29  * file:
  30  *
  31  * ASM: a very small and fast Java bytecode manipulation framework
  32  * Copyright (c) 2000-2011 INRIA, France Telecom
  33  * All rights reserved.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 3. Neither the name of the copyright holders nor the names of its
  44  *    contributors may be used to endorse or promote products derived from
  45  *    this software without specific prior written permission.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  48  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  50  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  51  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  52  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  53  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  54  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  55  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  56  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  57  * THE POSSIBILITY OF SUCH DAMAGE.
  58  */
  59 package jdk.internal.org.objectweb.asm.commons;
  60 
  61 import jdk.internal.org.objectweb.asm.ClassVisitor;
  62 import jdk.internal.org.objectweb.asm.MethodVisitor;
  63 import jdk.internal.org.objectweb.asm.Opcodes;
  64 
  65 /**
  66  * A {@link ClassVisitor} that merges clinit methods into a single one.
  67  *
  68  * @author Eric Bruneton
  69  */
  70 public class StaticInitMerger extends ClassVisitor {
  71 
  72     private String name;
  73 
  74     private MethodVisitor clinit;
  75 
  76     private final String prefix;
  77 
  78     private int counter;
  79 
  80     public StaticInitMerger(final String prefix, final ClassVisitor cv) {
  81         this(Opcodes.ASM5, prefix, cv);
  82     }
  83 
  84     protected StaticInitMerger(final int api, final String prefix,
  85             final ClassVisitor cv) {
  86         super(api, cv);
  87         this.prefix = prefix;
  88     }
  89 
  90     @Override
  91     public void visit(final int version, final int access, final String name,
  92             final String signature, final String superName,
  93             final String[] interfaces) {
  94         cv.visit(version, access, name, signature, superName, interfaces);
  95         this.name = name;
  96     }
  97 
  98     @Override
  99     public MethodVisitor visitMethod(final int access, final String name,
 100             final String desc, final String signature, final String[] exceptions) {
 101         MethodVisitor mv;
 102         if ("<clinit>".equals(name)) {
 103             int a = Opcodes.ACC_PRIVATE + Opcodes.ACC_STATIC;
 104             String n = prefix + counter++;
 105             mv = cv.visitMethod(a, n, desc, signature, exceptions);
 106 
 107             if (clinit == null) {
 108                 clinit = cv.visitMethod(a, name, desc, null, null);
 109             }
 110             clinit.visitMethodInsn(Opcodes.INVOKESTATIC, this.name, n, desc,
 111                     false);
 112         } else {
 113             mv = cv.visitMethod(access, name, desc, signature, exceptions);
 114         }
 115         return mv;
 116     }
 117 
 118     @Override
 119     public void visitEnd() {
 120         if (clinit != null) {
 121             clinit.visitInsn(Opcodes.RETURN);
 122             clinit.visitMaxs(0, 0);
 123         }
 124         cv.visitEnd();
 125     }
 126 }