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/*
* Copyright 2002-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
*/
package sun.jvm.hotspot.tools.jcore;
import sun.jvm.hotspot.oops.*;
import sun.jvm.hotspot.interpreter.*;
import sun.jvm.hotspot.utilities.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.runtime.*;
public class ByteCodeRewriter
{
private Method method;
private ConstantPool cpool;
private ConstantPoolCache cpCache;
private byte[] code;
private Bytes bytes;
public static final boolean DEBUG = false;
private static final int jintSize = 4;
protected void debugMessage(String message) {
System.out.println(message);
}
public ByteCodeRewriter(Method method, ConstantPool cpool, byte[] code) {
this.method = method;
this.cpool = cpool;
this.cpCache = cpool.getCache();
this.code = code;
this.bytes = VM.getVM().getBytes();
}
protected short getConstantPoolIndex(int bci) {
// get ConstantPool index from ConstantPoolCacheIndex at given bci
short cpCacheIndex = method.getBytecodeShortArg(bci);
if (cpCache == null) {
return cpCacheIndex;
} else {
// change byte-ordering and go via cache
return (short) cpCache.getEntryAt((int) (0xFFFF & bytes.swapShort(cpCacheIndex))).getConstantPoolIndex();
}
}
static private void writeShort(byte[] buf, int index, short value) {
buf[index] = (byte) ((value >> 8) & 0x00FF);
buf[index + 1] = (byte) (value & 0x00FF);
}
public void rewrite() {
int bytecode = Bytecodes._illegal;
int hotspotcode = Bytecodes._illegal;
int len = 0;
for (int bci = 0; bci < code.length;) {
hotspotcode = Bytecodes.codeAt(method, bci);
bytecode = Bytecodes.javaCode(hotspotcode);
if (Assert.ASSERTS_ENABLED) {
int code_from_buffer = 0xFF & code[bci];
Assert.that(code_from_buffer == hotspotcode
|| code_from_buffer == Bytecodes._breakpoint,
"Unexpected bytecode found in method bytecode buffer!");
}
// update the code buffer hotspot specific bytecode with the jvm bytecode
code[bci] = (byte) (0xFF & bytecode);
short cpoolIndex = 0;
switch (bytecode) {
// bytecodes with ConstantPoolCache index
case Bytecodes._getstatic:
case Bytecodes._putstatic:
case Bytecodes._getfield:
case Bytecodes._putfield:
case Bytecodes._invokevirtual:
case Bytecodes._invokespecial:
case Bytecodes._invokestatic:
case Bytecodes._invokeinterface: {
cpoolIndex = getConstantPoolIndex(bci + 1);
writeShort(code, bci + 1, cpoolIndex);
break;
}
}
len = Bytecodes.lengthFor(bytecode);
if (len <= 0) len = Bytecodes.lengthAt(method, bci);
if (DEBUG) {
String operand = "";
switch (len) {
case 2:
operand += code[bci + 1];
break;
case 3:
operand += (cpoolIndex != 0)? cpoolIndex :
method.getBytecodeShortArg(bci + 1);
break;
case 5:
operand += method.getBytecodeIntArg(bci + 1);
break;
}
// the operand following # is not quite like javap output.
// in particular, for goto & goto_w, the operand is PC relative
// offset for jump. Javap adds relative offset with current PC
// to give absolute bci to jump to.
String message = "\t\t" + bci + " " + Bytecodes.name(bytecode);
if (hotspotcode != bytecode)
message += " [" + Bytecodes.name(hotspotcode) + "]";
if (operand != "")
message += " #" + operand;
if (DEBUG) debugMessage(message);
}
bci += len;
}
}
}
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