/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.vm;
import org.jnode.vm.classmgr.VmByteCode;
import org.jnode.vm.classmgr.VmMethod;
import org.jnode.vm.classmgr.VmType;
import org.jnode.vm.objects.VmSystemObject;
/**
* A VmFrame is the execution frame (locals & stack) for a method during
* execution. Note that this class is not meant to be a normal java class,
* instead it is a record structure that maps directly on how a method frame is
* push on the stack by the compiler. Don't add any methods, since during
* runtime instances of this class will have no header and thus no virtual
* method table.
*/
public final class VmStackFrame extends VmSystemObject {
public static final int MAGIC_MASK = 0xFFFFFF00;
public static final int MAGIC_COMPILED = 0x21A52F00;
/**
* The method executing in this frame
*/
private final VmMethod sfMethod;
private final int programCounter;
/**
* Initialize this instance.
*
* @param src
* @param reader
*/
VmStackFrame(VmMethod method, int programCounter) {
this.sfMethod = method;
this.programCounter = programCounter;
}
/**
* @return Returns the method.
*/
public final VmMethod getMethod() {
return this.sfMethod;
}
/**
* Gets the line number of the current instruction of this frame.
*
* @return The line number, or -1 if not found.
*/
public final String getLocationInfo() {
int lineNo = -1;
if (sfMethod != null) {
final VmByteCode bc = sfMethod.getBytecode();
if (bc != null) {
lineNo = bc.getLineNr(programCounter);
}
}
if (lineNo >= 0) {
return String.valueOf(lineNo);
} else {
return "?";
}
}
/**
* Convert to a String representation.
*
* @see java.lang.Object#toString()
*/
public String toString() {
final VmMethod method = sfMethod;
final VmType<?> vmClass = (method == null) ? null : method.getDeclaringClass();
final String cname = (vmClass == null) ? "<unknown class>" : vmClass.getName();
final String mname = (method == null) ? "<unknown method>" : method.getName();
final String location = getLocationInfo();
return cname + '!' + mname + " (" + location + ')';
}
}