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Java example source code file (Disassembler.java)

This example Java source code file (Disassembler.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

address, codeblob, disassembler, linux, mac, nmethod, string, stringbuilder, sunos, throwable, util, windows

The Disassembler.java Java example source code

/*
 * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

package sun.jvm.hotspot.asm;

import java.io.PrintStream;
import java.util.Observer;
import java.util.Observable;
import sun.jvm.hotspot.code.CodeBlob;
import sun.jvm.hotspot.code.NMethod;
import sun.jvm.hotspot.debugger.Address;
import sun.jvm.hotspot.runtime.VM;

public class Disassembler {
   private static String options = "";
   private static long decode_function;

   protected long startPc;
   protected byte[] code;
   private CodeBlob blob;
   private NMethod nmethod;

   public static void decode(InstructionVisitor visitor, CodeBlob blob) {
      decode(visitor, blob, blob.codeBegin(), blob.codeEnd());
   }

   public static void decode(InstructionVisitor visitor, CodeBlob blob, Address begin, Address end) {
      int codeSize = (int)end.minus(begin);
      long startPc = VM.getAddressValue(begin);
      byte[] code = new byte[codeSize];
      for (int i = 0; i < code.length; i++)
         code[i] = begin.getJByteAt(i);
      Disassembler dis = new Disassembler(startPc, code);
      dis.decode(visitor);
   }

   private Disassembler(long startPc, byte[] code) {
      this.startPc = startPc;
      this.code = code;

      // Lazily load hsdis
      if (decode_function == 0) {
         StringBuilder path = new StringBuilder(System.getProperty("java.home"));
         String sep = System.getProperty("file.separator");
         String os = System.getProperty("os.name");
         String libname = "hsdis";
         String arch = System.getProperty("os.arch");
         if (os.lastIndexOf("Windows", 0) != -1) {
            if (arch.equals("x86")) {
               libname +=  "-i386";
            } else if (arch.equals("amd64")) {
               libname +=  "-amd64";
            } else {
               libname +=  "-" + arch;
            }
            path.append(sep + "bin" + sep);
            libname += ".dll";
         } else if (os.lastIndexOf("SunOS", 0) != -1) {
            if (arch.equals("x86") || arch.equals("i386")) {
               path.append(sep + "lib" + sep + "i386" + sep);
               libname +=  "-i386" + ".so";
            } else if (arch.equals("amd64")) {
               path.append(sep + "lib" + sep + "amd64" + sep);
               libname +=  "-amd64" + ".so";
            } else {
               path.append(sep + "lib" + sep + arch + sep);
               libname +=  "-" + arch + ".so";
            }
         } else if (os.lastIndexOf("Linux", 0) != -1) {
            if (arch.equals("x86") || arch.equals("i386")) {
               path.append(sep + "lib" + sep + "i386" + sep);
               libname += "-i386.so";
            } else if (arch.equals("amd64") || arch.equals("x86_64")) {
               path.append(sep + "lib" + sep + "amd64" + sep);
               libname +=  "-amd64.so";
            } else {
               path.append(sep + "lib" + sep + arch + sep);
               libname +=  "-" + arch + ".so";
            }
         } else if (os.lastIndexOf("Mac OS X", 0) != -1) {
            path.append(sep + "lib" + sep);
            libname += "-amd64" + ".dylib";       // x86_64 => amd64
         } else {
            path.append(sep + "lib" + sep + "arch" + sep);
            libname +=  "-" + arch + ".so";
         }
         decode_function = load_library(path.toString(), libname);
      }
   }

   private static native long load_library(String installed_jrepath, String hsdis_library_name);

   private native void decode(InstructionVisitor visitor, long pc, byte[] code,
                              String options, long decode_function);

   private void decode(InstructionVisitor visitor) {
      visitor.prologue();
      decode(visitor, startPc, code, options, decode_function);
      visitor.epilogue();
   }

   private boolean match(String event, String tag) {
      if (!event.startsWith(tag))
         return false;
      int taglen = tag.length();
      if (taglen == event.length()) return true;
      char delim = event.charAt(taglen);
      return delim == ' ' || delim == '/' || delim == '=';
   }

   // This is called from the native code to process various markers
   // in the dissassembly.
   private long handleEvent(InstructionVisitor visitor, String event, long arg) {
      if (match(event, "insn")) {
         try {
            visitor.beginInstruction(arg);
         } catch (Throwable e) {
            e.printStackTrace();
         }
      } else if (match(event, "/insn")) {
         try {
            visitor.endInstruction(arg);
         } catch (Throwable e) {
            e.printStackTrace();
         }
      } else if (match(event, "addr")) {
         if (arg != 0) {
            visitor.printAddress(arg);
         }
         return arg;
      } else if (match(event, "mach")) {
         // output().printf("[Disassembling for mach='%s']\n", arg);
      } else {
         // ignore unrecognized markup
      }
      return 0;
   }

   // This called from the native code to perform printing
   private  void rawPrint(InstructionVisitor visitor, String s) {
      visitor.print(s);
   }
}

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