1 /*
   2  * Copyright (c) 2001, 2004, 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 
  25 package sun.jvm.hotspot.interpreter;
  26 
  27 import sun.jvm.hotspot.oops.*;
  28 import sun.jvm.hotspot.utilities.*;
  29 import sun.jvm.hotspot.runtime.VM;
  30 
  31 public class Bytecode {
  32   Method method;
  33   int bci;
  34   static final int jintSize = 4;
  35   static final String spaces = " ";
  36   static final String comma  = ", ";
  37 
  38   Bytecode(Method method, int bci) {
  39     this.method = method;
  40     this.bci    = bci;
  41   }
  42 
  43   // Address computation
  44   // NOTE: assumes that the start of the method's bytecodes is 4-byte aligned
  45   int alignedOffset(int offset) {
  46     return Bits.roundTo(bci + offset, jintSize) - bci;
  47   }
  48 
  49   public int     getIndexU1()               { return method.getBytecodeOrBPAt(bci() + 1) & 0xFF; }
  50   public int     getIndexU2(int bc, boolean isWide) {
  51     if (can_use_native_byte_order(bc, isWide)) {
  52       return method.getNativeShortArg(bci() + (isWide ? 2 : 1)) & 0xFFFF;
  53     }
  54     return method.getBytecodeShortArg(bci() + (isWide ? 2 : 1)) & 0xFFFF;
  55   }
  56   public int     getIndexU4()               { return method.getNativeIntArg(bci() + 1); }
  57   public boolean hasIndexU4()               { return code() == Bytecodes._invokedynamic; }
  58 
  59   public int     getIndexU1Cpcache()        { return method.getBytecodeOrBPAt(bci() + 1) & 0xFF; }
  60   public int     getIndexU2Cpcache()        { return method.getNativeShortArg(bci() + 1) & 0xFFFF; }
  61 
  62   static boolean can_use_native_byte_order(int bc, boolean is_wide) {
  63     return (VM.getVM().isBigEndian() || Bytecodes.native_byte_order(bc /*, is_wide*/));
  64   }
  65 
  66   int javaSignedWordAt(int offset) {
  67     return method.getBytecodeIntArg(bci + offset);
  68   }
  69 
  70   short javaShortAt(int offset) {
  71     return method.getBytecodeShortArg(bci + offset);
  72   }
  73 
  74   byte javaByteAt(int offset) {
  75     return method.getBytecodeByteArg(bci + offset);
  76   }
  77 
  78   public Method method() { return method; }
  79   public int    bci()    { return bci;    }
  80 
  81   // hotspot byte code
  82   public int code() {
  83     return Bytecodes.codeAt(method(), bci());
  84   }
  85 
  86   // jvm byte code
  87   public int javaCode() {
  88     return Bytecodes.javaCode(code());
  89   }
  90 
  91   public String getBytecodeName() {
  92     return Bytecodes.name(code());
  93   }
  94 
  95   public String getJavaBytecodeName() {
  96     return Bytecodes.name(javaCode());
  97   }
  98 
  99   public int getLength() {
 100     return Bytecodes.lengthAt(method(), bci());
 101   }
 102 
 103   public int getJavaLength() {
 104     return Bytecodes.javaLengthAt(method(), bci());
 105   }
 106 
 107   public String toString() {
 108     StringBuffer buf = new StringBuffer(getJavaBytecodeName());
 109     if (code() != javaCode()) {
 110        buf.append(spaces);
 111        buf.append('[');
 112        buf.append(getBytecodeName());
 113        buf.append(']');
 114     }
 115     return buf.toString();
 116   }
 117 }