/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
package com.sun.org.apache.bcel.internal.generic;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" and
* "Apache BCEL" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* "Apache BCEL", nor may "Apache" appear in their name, without
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*
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
import com.sun.org.apache.bcel.internal.Constants;
import com.sun.org.apache.bcel.internal.classfile.Constant;
import com.sun.org.apache.bcel.internal.util.ByteSequence;
import java.io.*;
import java.util.Iterator;
import java.util.HashMap;
import java.util.ArrayList;
/**
* This class is a container for a list of <a
* href="Instruction.html">Instruction</a> objects. Instructions can
* be appended, inserted, moved, deleted, etc.. Instructions are being
* wrapped into <a
* href="InstructionHandle.html">InstructionHandles</a> objects that
* are returned upon append/insert operations. They give the user
* (read only) access to the list structure, such that it can be traversed and
* manipulated in a controlled way.
*
* A list is finally dumped to a byte code array with <a
* href="#getByteCode()">getByteCode</a>.
*
* @version $Id: InstructionList.java,v 1.1.2.1 2005/07/31 23:45:45 jeffsuttor Exp $
* @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
* @see Instruction
* @see InstructionHandle
* @see BranchHandle
*/
public class InstructionList implements Serializable {
private InstructionHandle start = null, end = null;
private int length = 0; // number of elements in list
private int[] byte_positions; // byte code offsets corresponding to instructions
/**
* Create (empty) instruction list.
*/
public InstructionList() {}
/**
* Create instruction list containing one instruction.
* @param i initial instruction
*/
public InstructionList(Instruction i) {
append(i);
}
/**
* Create instruction list containing one instruction.
* @param i initial instruction
*/
public InstructionList(BranchInstruction i) {
append(i);
}
/**
* Initialize list with (nonnull) compound instruction. Consumes argument
* list, i.e., it becomes empty.
*
* @param c compound instruction (list)
*/
public InstructionList(CompoundInstruction c) {
append(c.getInstructionList());
}
/**
* Test for empty list.
*/
public boolean isEmpty() { return start == null; } // && end == null
/**
* Find the target instruction (handle) that corresponds to the given target
* position (byte code offset).
*
* @param ihs array of instruction handles, i.e. il.getInstructionHandles()
* @param pos array of positions corresponding to ihs, i.e. il.getInstructionPositions()
* @param count length of arrays
* @param target target position to search for
* @return target position's instruction handle if available
*/
public static InstructionHandle findHandle(InstructionHandle[] ihs,
int[] pos, int count,
int target) {
int l=0, r = count - 1;
/* Do a binary search since the pos array is orderd.
*/
do {
int i = (l + r) / 2;
int j = pos[i];
if(j == target) // target found
return ihs[i];
else if(target < j) // else constrain search area
r = i - 1;
else // target > j
l = i + 1;
} while(l <= r);
return null;
}
/**
* Get instruction handle for instruction at byte code position pos.
* This only works properly, if the list is freshly initialized from a byte array or
* setPositions() has been called before this method.
*
* @param pos byte code position to search for
* @return target position's instruction handle if available
*/
public InstructionHandle findHandle(int pos) {
InstructionHandle[] ihs = getInstructionHandles();
return findHandle(ihs, byte_positions, length, pos);
}
/**
* Initialize instruction list from byte array.
*
* @param code byte array containing the instructions
*/
public InstructionList(byte[] code) {
ByteSequence bytes = new ByteSequence(code);
InstructionHandle[] ihs = new InstructionHandle[code.length];
int[] pos = new int[code.length]; // Can't be more than that
int count = 0; // Contains actual length
/* Pass 1: Create an object for each byte code and append them
* to the list.
*/
try {
while(bytes.available() > 0) {
// Remember byte offset and associate it with the instruction
int off = bytes.getIndex();
pos[count] = off;
/* Read one instruction from the byte stream, the byte position is set
* accordingly.
*/
Instruction i = Instruction.readInstruction(bytes);
InstructionHandle ih;
if(i instanceof BranchInstruction) // Use proper append() method
ih = append((BranchInstruction)i);
else
ih = append(i);
ih.setPosition(off);
ihs[count] = ih;
count++;
}
} catch(IOException e) { throw new ClassGenException(e.toString()); }
byte_positions = new int[count]; // Trim to proper size
System.arraycopy(pos, 0, byte_positions, 0, count);
/* Pass 2: Look for BranchInstruction and update their targets, i.e.,
* convert offsets to instruction handles.
*/
for(int i=0; i < count; i++) {
if(ihs[i] instanceof BranchHandle) {
BranchInstruction bi = (BranchInstruction)ihs[i].instruction;
int target = bi.position + bi.getIndex(); /* Byte code position:
* relative -> absolute. */
// Search for target position
InstructionHandle ih = findHandle(ihs, pos, count, target);
if(ih == null) // Search failed
throw new ClassGenException("Couldn't find target for branch: " + bi);
bi.setTarget(ih); // Update target
// If it is a Select instruction, update all branch targets
if(bi instanceof Select) { // Either LOOKUPSWITCH or TABLESWITCH
Select s = (Select)bi;
int[] indices = s.getIndices();
for(int j=0; j < indices.length; j++) {
target = bi.position + indices[j];
ih = findHandle(ihs, pos, count, target);
if(ih == null) // Search failed
throw new ClassGenException("Couldn't find target for switch: " + bi);
s.setTarget(j, ih); // Update target
}
}
}
}
}
/**
* Append another list after instruction (handle) ih contained in this list.
* Consumes argument list, i.e., it becomes empty.
*
* @param ih where to append the instruction list
* @param il Instruction list to append to this one
* @return instruction handle pointing to the <B>first</B> appended instruction
*/
public InstructionHandle append(InstructionHandle ih, InstructionList il) {
if(il == null)
throw new ClassGenException("Appending null InstructionList");
if(il.isEmpty()) // Nothing to do
return ih;
InstructionHandle next = ih.next, ret = il.start;
ih.next = il.start;
il.start.prev = ih;
il.end.next = next;
if(next != null) // i == end ?
next.prev = il.end;
else
end = il.end; // Update end ...
length += il.length; // Update length
il.clear();
return ret;
}
/**
* Append another list after instruction i contained in this list.
* Consumes argument list, i.e., it becomes empty.
*
* @param i where to append the instruction list
* @param il Instruction list to append to this one
* @return instruction handle pointing to the <B>first</B> appended instruction
*/
public InstructionHandle append(Instruction i, InstructionList il) {
InstructionHandle ih;
if((ih = findInstruction2(i)) == null) // Also applies for empty list
throw new ClassGenException("Instruction " + i +
" is not contained in this list.");
return append(ih, il);
}
/**
* Append another list to this one.
* Consumes argument list, i.e., it becomes empty.
*
* @param il list to append to end of this list
* @return instruction handle of the <B>first</B> appended instruction
*/
public InstructionHandle append(InstructionList il) {
if(il == null)
throw new ClassGenException("Appending null InstructionList");
if(il.isEmpty()) // Nothing to do
return null;
if(isEmpty()) {
start = il.start;
end = il.end;
length = il.length;
il.clear();
return start;
} else
return append(end, il); // was end.instruction
}
/**
* Append an instruction to the end of this list.
*
* @param ih instruction to append
*/
private void append(InstructionHandle ih) {
if(isEmpty()) {
start = end = ih;
ih.next = ih.prev = null;
}
else {
end.next = ih;
ih.prev = end;
ih.next = null;
end = ih;
}
length++; // Update length
}
/**
* Append an instruction to the end of this list.
*
* @param i instruction to append
* @return instruction handle of the appended instruction
*/
public InstructionHandle append(Instruction i) {
InstructionHandle ih = InstructionHandle.getInstructionHandle(i);
append(ih);
return ih;
}
/**
* Append a branch instruction to the end of this list.
*
* @param i branch instruction to append
* @return branch instruction handle of the appended instruction
*/
public BranchHandle append(BranchInstruction i) {
BranchHandle ih = BranchHandle.getBranchHandle(i);
append(ih);
return ih;
}
/**
* Append a single instruction j after another instruction i, which
* must be in this list of course!
*
* @param i Instruction in list
* @param j Instruction to append after i in list
* @return instruction handle of the first appended instruction
*/
public InstructionHandle append(Instruction i, Instruction j) {
return append(i, new InstructionList(j));
}
/**
* Append a compound instruction, after instruction i.
*
* @param i Instruction in list
* @param c The composite instruction (containing an InstructionList)
* @return instruction handle of the first appended instruction
*/
public InstructionHandle append(Instruction i, CompoundInstruction c) {
return append(i, c.getInstructionList());
}
/**
* Append a compound instruction.
*
* @param c The composite instruction (containing an InstructionList)
* @return instruction handle of the first appended instruction
*/
public InstructionHandle append(CompoundInstruction c) {
return append(c.getInstructionList());
}
/**
* Append a compound instruction.
*
* @param ih where to append the instruction list
* @param c The composite instruction (containing an InstructionList)
* @return instruction handle of the first appended instruction
*/
public InstructionHandle append(InstructionHandle ih, CompoundInstruction c) {
return append(ih, c.getInstructionList());
}
/**
* Append an instruction after instruction (handle) ih contained in this list.
*
* @param ih where to append the instruction list
* @param i Instruction to append
* @return instruction handle pointing to the <B>first</B> appended instruction
*/
public InstructionHandle append(InstructionHandle ih, Instruction i) {
return append(ih, new InstructionList(i));
}
/**
* Append an instruction after instruction (handle) ih contained in this list.
*
* @param ih where to append the instruction list
* @param i Instruction to append
* @return instruction handle pointing to the <B>first</B> appended instruction
*/
public BranchHandle append(InstructionHandle ih, BranchInstruction i) {
BranchHandle bh = BranchHandle.getBranchHandle(i);
InstructionList il = new InstructionList();
il.append(bh);
append(ih, il);
return bh;
}
/**
* Insert another list before Instruction handle ih contained in this list.
* Consumes argument list, i.e., it becomes empty.
*
* @param i where to append the instruction list
* @param il Instruction list to insert
* @return instruction handle of the first inserted instruction
*/
public InstructionHandle insert(InstructionHandle ih, InstructionList il) {
if(il == null)
throw new ClassGenException("Inserting null InstructionList");
if(il.isEmpty()) // Nothing to do
return ih;
InstructionHandle prev = ih.prev, ret = il.start;
ih.prev = il.end;
il.end.next = ih;
il.start.prev = prev;
if(prev != null) // ih == start ?
prev.next = il.start;
else
start = il.start; // Update start ...
length += il.length; // Update length
il.clear();
return ret;
}
/**
* Insert another list.
*
* @param il list to insert before start of this list
* @return instruction handle of the first inserted instruction
*/
public InstructionHandle insert(InstructionList il) {
if(isEmpty()) {
append(il); // Code is identical for this case
return start;
}
else
return insert(start, il);
}
/**
* Insert an instruction at start of this list.
*
* @param ih instruction to insert
*/
private void insert(InstructionHandle ih) {
if(isEmpty()) {
start = end = ih;
ih.next = ih.prev = null;
} else {
start.prev = ih;
ih.next = start;
ih.prev = null;
start = ih;
}
length++;
}
/**
* Insert another list before Instruction i contained in this list.
* Consumes argument list, i.e., it becomes empty.
*
* @param i where to append the instruction list
* @param il Instruction list to insert
* @return instruction handle pointing to the first inserted instruction,
* i.e., il.getStart()
*/
public InstructionHandle insert(Instruction i, InstructionList il) {
InstructionHandle ih;
if((ih = findInstruction1(i)) == null)
throw new ClassGenException("Instruction " + i +
" is not contained in this list.");
return insert(ih, il);
}
/**
* Insert an instruction at start of this list.
*
* @param i instruction to insert
* @return instruction handle of the inserted instruction
*/
public InstructionHandle insert(Instruction i) {
InstructionHandle ih = InstructionHandle.getInstructionHandle(i);
insert(ih);
return ih;
}
/**
* Insert a branch instruction at start of this list.
*
* @param i branch instruction to insert
* @return branch instruction handle of the appended instruction
*/
public BranchHandle insert(BranchInstruction i) {
BranchHandle ih = BranchHandle.getBranchHandle(i);
insert(ih);
return ih;
}
/**
* Insert a single instruction j before another instruction i, which
* must be in this list of course!
*
* @param i Instruction in list
* @param j Instruction to insert before i in list
* @return instruction handle of the first inserted instruction
*/
public InstructionHandle insert(Instruction i, Instruction j) {
return insert(i, new InstructionList(j));
}
/**
* Insert a compound instruction before instruction i.
*
* @param i Instruction in list
* @param c The composite instruction (containing an InstructionList)
* @return instruction handle of the first inserted instruction
*/
public InstructionHandle insert(Instruction i, CompoundInstruction c) {
return insert(i, c.getInstructionList());
}
/**
* Insert a compound instruction.
*
* @param c The composite instruction (containing an InstructionList)
* @return instruction handle of the first inserted instruction
*/
public InstructionHandle insert(CompoundInstruction c) {
return insert(c.getInstructionList());
}
/**
* Insert an instruction before instruction (handle) ih contained in this list.
*
* @param ih where to insert to the instruction list
* @param i Instruction to insert
* @return instruction handle of the first inserted instruction
*/
public InstructionHandle insert(InstructionHandle ih, Instruction i) {
return insert(ih, new InstructionList(i));
}
/**
* Insert a compound instruction.
*
* @param ih where to insert the instruction list
* @param c The composite instruction (containing an InstructionList)
* @return instruction handle of the first inserted instruction
*/
public InstructionHandle insert(InstructionHandle ih, CompoundInstruction c) {
return insert(ih, c.getInstructionList());
}
/**
* Insert an instruction before instruction (handle) ih contained in this list.
*
* @param ih where to insert to the instruction list
* @param i Instruction to insert
* @return instruction handle of the first inserted instruction
*/
public BranchHandle insert(InstructionHandle ih, BranchInstruction i) {
BranchHandle bh = BranchHandle.getBranchHandle(i);
InstructionList il = new InstructionList();
il.append(bh);
insert(ih, il);
return bh;
}
/**
* Take all instructions (handles) from "start" to "end" and append them after the
* new location "target". Of course, "end" must be after "start" and target must
* not be located withing this range. If you want to move something to the start of
* the list use null as value for target.<br>
* Any instruction targeters pointing to handles within the block, keep their targets.
*
* @param start of moved block
* @param end of moved block
* @param target of moved block
*/
public void move(InstructionHandle start, InstructionHandle end, InstructionHandle target) {
// Step 1: Check constraints
if((start == null) || (end == null))
throw new ClassGenException("Invalid null handle: From " + start + " to " + end);
if((target == start) || (target == end))
throw new ClassGenException("Invalid range: From " + start + " to " + end +
" contains target " + target);
for(InstructionHandle ih = start; ih != end.next; ih = ih.next) {
if(ih == null) // At end of list, end not found yet
throw new ClassGenException("Invalid range: From " + start + " to " + end);
else if(ih == target) // target may be null
throw new ClassGenException("Invalid range: From " + start + " to " + end +
" contains target " + target);
}
// Step 2: Temporarily remove the given instructions from the list
InstructionHandle prev = start.prev, next = end.next;
if(prev != null)
prev.next = next;
else // start == this.start!
this.start = next;
if(next != null)
next.prev = prev;
else // end == this.end!
this.end = prev;
start.prev = end.next = null;
// Step 3: append after target
if(target == null) { // append to start of list
end.next = this.start;
this.start = start;
} else {
next = target.next;
target.next = start;
start.prev = target;
end.next = next;
if(next != null)
next.prev = end;
}
}
/**
* Move a single instruction (handle) to a new location.
*
* @param ih moved instruction
* @param target new location of moved instruction
*/
public void move(InstructionHandle ih, InstructionHandle target) {
move(ih, ih, target);
}
/**
* Remove from instruction `prev' to instruction `next' both contained
* in this list. Throws TargetLostException when one of the removed instruction handles
* is still being targeted.
*
* @param prev where to start deleting (predecessor, exclusive)
* @param next where to end deleting (successor, exclusive)
*/
private void remove(InstructionHandle prev, InstructionHandle next)
throws TargetLostException
{
InstructionHandle first, last; // First and last deleted instruction
if((prev == null) && (next == null)) { // singleton list
first = last = start;
start = end = null;
} else {
if(prev == null) { // At start of list
first = start;
start = next;
} else {
first = prev.next;
prev.next = next;
}
if(next == null) { // At end of list
last = end;
end = prev;
} else {
last = next.prev;
next.prev = prev;
}
}
first.prev = null; // Completely separated from rest of list
last.next = null;
ArrayList target_vec = new ArrayList();
for(InstructionHandle ih=first; ih != null; ih = ih.next)
ih.getInstruction().dispose(); // e.g. BranchInstructions release their targets
StringBuffer buf = new StringBuffer("{ ");
for(InstructionHandle ih=first; ih != null; ih = next) {
next = ih.next;
length--;
if(ih.hasTargeters()) { // Still got targeters?
target_vec.add(ih);
buf.append(ih.toString(true) + " ");
ih.next = ih.prev = null;
} else
ih.dispose();
}
buf.append("}");
if(!target_vec.isEmpty()) {
InstructionHandle[] targeted = new InstructionHandle[target_vec.size()];
target_vec.toArray(targeted);
throw new TargetLostException(targeted, buf.toString());
}
}
/**
* Remove instruction from this list. The corresponding Instruction
* handles must not be reused!
*
* @param ih instruction (handle) to remove
*/
public void delete(InstructionHandle ih) throws TargetLostException {
remove(ih.prev, ih.next);
}
/**
* Remove instruction from this list. The corresponding Instruction
* handles must not be reused!
*
* @param i instruction to remove
*/
public void delete(Instruction i) throws TargetLostException {
InstructionHandle ih;
if((ih = findInstruction1(i)) == null)
throw new ClassGenException("Instruction " + i +
" is not contained in this list.");
delete(ih);
}
/**
* Remove instructions from instruction `from' to instruction `to' contained
* in this list. The user must ensure that `from' is an instruction before
* `to', or risk havoc. The corresponding Instruction handles must not be reused!
*
* @param from where to start deleting (inclusive)
* @param to where to end deleting (inclusive)
*/
public void delete(InstructionHandle from, InstructionHandle to)
throws TargetLostException
{
remove(from.prev, to.next);
}
/**
* Remove instructions from instruction `from' to instruction `to' contained
* in this list. The user must ensure that `from' is an instruction before
* `to', or risk havoc. The corresponding Instruction handles must not be reused!
*
* @param from where to start deleting (inclusive)
* @param to where to end deleting (inclusive)
*/
public void delete(Instruction from, Instruction to) throws TargetLostException {
InstructionHandle from_ih, to_ih;
if((from_ih = findInstruction1(from)) == null)
throw new ClassGenException("Instruction " + from +
" is not contained in this list.");
if((to_ih = findInstruction2(to)) == null)
throw new ClassGenException("Instruction " + to +
" is not contained in this list.");
delete(from_ih, to_ih);
}
/**
* Search for given Instruction reference, start at beginning of list.
*
* @param i instruction to search for
* @return instruction found on success, null otherwise
*/
private InstructionHandle findInstruction1(Instruction i) {
for(InstructionHandle ih=start; ih != null; ih = ih.next)
if(ih.instruction == i)
return ih;
return null;
}
/**
* Search for given Instruction reference, start at end of list
*
* @param i instruction to search for
* @return instruction found on success, null otherwise
*/
private InstructionHandle findInstruction2(Instruction i) {
for(InstructionHandle ih=end; ih != null; ih = ih.prev)
if(ih.instruction == i)
return ih;
return null;
}
public boolean contains(InstructionHandle i) {
if(i == null)
return false;
for(InstructionHandle ih=start; ih != null; ih = ih.next)
if(ih == i)
return true;
return false;
}
public boolean contains(Instruction i) {
return findInstruction1(i) != null;
}
public void setPositions() {
setPositions(false);
}
/**
* Give all instructions their position number (offset in byte stream), i.e.,
* make the list ready to be dumped.
*
* @param check Perform sanity checks, e.g. if all targeted instructions really belong
* to this list
*/
public void setPositions(boolean check) {
int max_additional_bytes = 0, additional_bytes = 0;
int index = 0, count = 0;
int[] pos = new int[length];
/* Pass 0: Sanity checks
*/
if(check) {
for(InstructionHandle ih=start; ih != null; ih = ih.next) {
Instruction i = ih.instruction;
if(i instanceof BranchInstruction) { // target instruction within list?
Instruction inst = ((BranchInstruction)i).getTarget().instruction;
if(!contains(inst))
throw new ClassGenException("Branch target of " +
Constants.OPCODE_NAMES[i.opcode] + ":" +
inst + " not in instruction list");
if(i instanceof Select) {
InstructionHandle[] targets = ((Select)i).getTargets();
for(int j=0; j < targets.length; j++) {
inst = targets[j].instruction;
if(!contains(inst))
throw new ClassGenException("Branch target of " +
Constants.OPCODE_NAMES[i.opcode] + ":" +
inst + " not in instruction list");
}
}
if(!(ih instanceof BranchHandle))
throw new ClassGenException("Branch instruction " +
Constants.OPCODE_NAMES[i.opcode] + ":" +
inst + " not contained in BranchHandle.");
}
}
}
/* Pass 1: Set position numbers and sum up the maximum number of bytes an
* instruction may be shifted.
*/
for(InstructionHandle ih=start; ih != null; ih = ih.next) {
Instruction i = ih.instruction;
ih.setPosition(index);
pos[count++] = index;
/* Get an estimate about how many additional bytes may be added, because
* BranchInstructions may have variable length depending on the target
* offset (short vs. int) or alignment issues (TABLESWITCH and
* LOOKUPSWITCH).
*/
switch(i.getOpcode()) {
case Constants.JSR: case Constants.GOTO:
max_additional_bytes += 2;
break;
case Constants.TABLESWITCH: case Constants.LOOKUPSWITCH:
max_additional_bytes += 3;
break;
}
index += i.getLength();
}
/* Pass 2: Expand the variable-length (Branch)Instructions depending on
* the target offset (short or int) and ensure that branch targets are
* within this list.
*/
for(InstructionHandle ih=start; ih != null; ih = ih.next)
additional_bytes += ih.updatePosition(additional_bytes, max_additional_bytes);
/* Pass 3: Update position numbers (which may have changed due to the
* preceding expansions), like pass 1.
*/
index=count=0;
for(InstructionHandle ih=start; ih != null; ih = ih.next) {
Instruction i = ih.instruction;
ih.setPosition(index);
pos[count++] = index;
index += i.getLength();
}
byte_positions = new int[count]; // Trim to proper size
System.arraycopy(pos, 0, byte_positions, 0, count);
}
/**
* When everything is finished, use this method to convert the instruction
* list into an array of bytes.
*
* @return the byte code ready to be dumped
*/
public byte[] getByteCode() {
// Update position indices of instructions
setPositions();
ByteArrayOutputStream b = new ByteArrayOutputStream();
DataOutputStream out = new DataOutputStream(b);
try {
for(InstructionHandle ih=start; ih != null; ih = ih.next) {
Instruction i = ih.instruction;
i.dump(out); // Traverse list
}
} catch(IOException e) {
System.err.println(e);
return null;
}
return b.toByteArray();
}
/**
* @return an array of instructions without target information for branch instructions.
*/
public Instruction[] getInstructions() {
ByteSequence bytes = new ByteSequence(getByteCode());
ArrayList instructions = new ArrayList();
try {
while(bytes.available() > 0) {
instructions.add(Instruction.readInstruction(bytes));
}
} catch(IOException e) { throw new ClassGenException(e.toString()); }
Instruction[] result = new Instruction[instructions.size()];
instructions.toArray(result);
return result;
}
public String toString() {
return toString(true);
}
/**
* @param verbose toggle output format
* @return String containing all instructions in this list.
*/
public String toString(boolean verbose) {
StringBuffer buf = new StringBuffer();
for(InstructionHandle ih=start; ih != null; ih = ih.next) {
buf.append(ih.toString(verbose) + "\n");
}
return buf.toString();
}
/**
* @return Enumeration that lists all instructions (handles)
*/
public Iterator iterator() {
return new Iterator() {
private InstructionHandle ih = start;
public Object next() {
InstructionHandle i = ih;
ih = ih.next;
return i;
}
public void remove() {
throw new UnsupportedOperationException();
}
public boolean hasNext() { return ih != null; }
};
}
/**
* @return array containing all instructions (handles)
*/
public InstructionHandle[] getInstructionHandles() {
InstructionHandle[] ihs = new InstructionHandle[length];
InstructionHandle ih = start;
for(int i=0; i < length; i++) {
ihs[i] = ih;
ih = ih.next;
}
return ihs;
}
/**
* Get positions (offsets) of all instructions in the list. This relies on that
* the list has been freshly created from an byte code array, or that setPositions()
* has been called. Otherwise this may be inaccurate.
*
* @return array containing all instruction's offset in byte code
*/
public int[] getInstructionPositions() { return byte_positions; }
/**
* @return complete, i.e., deep copy of this list
*/
public InstructionList copy() {
HashMap map = new HashMap();
InstructionList il = new InstructionList();
/* Pass 1: Make copies of all instructions, append them to the new list
* and associate old instruction references with the new ones, i.e.,
* a 1:1 mapping.
*/
for(InstructionHandle ih=start; ih != null; ih = ih.next) {
Instruction i = ih.instruction;
Instruction c = i.copy(); // Use clone for shallow copy
if(c instanceof BranchInstruction)
map.put(ih, il.append((BranchInstruction)c));
else
map.put(ih, il.append(c));
}
/* Pass 2: Update branch targets.
*/
InstructionHandle ih=start;
InstructionHandle ch=il.start;
while(ih != null) {
Instruction i = ih.instruction;
Instruction c = ch.instruction;
if(i instanceof BranchInstruction) {
BranchInstruction bi = (BranchInstruction)i;
BranchInstruction bc = (BranchInstruction)c;
InstructionHandle itarget = bi.getTarget(); // old target
// New target is in hash map
bc.setTarget((InstructionHandle)map.get(itarget));
if(bi instanceof Select) { // Either LOOKUPSWITCH or TABLESWITCH
InstructionHandle[] itargets = ((Select)bi).getTargets();
InstructionHandle[] ctargets = ((Select)bc).getTargets();
for(int j=0; j < itargets.length; j++) { // Update all targets
ctargets[j] = (InstructionHandle)map.get(itargets[j]);
}
}
}
ih = ih.next;
ch = ch.next;
}
return il;
}
/** Replace all references to the old constant pool with references to the new
* constant pool
*/
public void replaceConstantPool(ConstantPoolGen old_cp, ConstantPoolGen new_cp) {
for(InstructionHandle ih=start; ih != null; ih = ih.next) {
Instruction i = ih.instruction;
if(i instanceof CPInstruction) {
CPInstruction ci = (CPInstruction)i;
Constant c = old_cp.getConstant(ci.getIndex());
ci.setIndex(new_cp.addConstant(c, old_cp));
}
}
}
private void clear() {
start = end = null;
length = 0;
}
/**
* Delete contents of list. Provides besser memory utilization,
* because the system then may reuse the instruction handles. This
* method is typically called right after
* <href="MethodGen.html#getMethod()">MethodGen.getMethod()</a>.
*/
public void dispose() {
// Traverse in reverse order, because ih.next is overwritten
for(InstructionHandle ih=end; ih != null; ih = ih.prev)
/* Causes BranchInstructions to release target and targeters, because it
* calls dispose() on the contained instruction.
*/
ih.dispose();
clear();
}
/**
* @return start of list
*/
public InstructionHandle getStart() { return start; }
/**
* @return end of list
*/
public InstructionHandle getEnd() { return end; }
/**
* @return length of list (Number of instructions, not bytes)
*/
public int getLength() { return length; }
/**
* @return length of list (Number of instructions, not bytes)
*/
public int size() { return length; }
/**
* Redirect all references from old_target to new_target, i.e., update targets
* of branch instructions.
*
* @param old_target the old target instruction handle
* @param new_target the new target instruction handle
*/
public void redirectBranches(InstructionHandle old_target,
InstructionHandle new_target) {
for(InstructionHandle ih = start; ih != null; ih = ih.next) {
Instruction i = ih.getInstruction();
if(i instanceof BranchInstruction) {
BranchInstruction b = (BranchInstruction)i;
InstructionHandle target = b.getTarget();
if(target == old_target)
b.setTarget(new_target);
if(b instanceof Select) { // Either LOOKUPSWITCH or TABLESWITCH
InstructionHandle[] targets = ((Select)b).getTargets();
for(int j=0; j < targets.length; j++) // Update targets
if(targets[j] == old_target)
((Select)b).setTarget(j, new_target);
}
}
}
}
/**
* Redirect all references of local variables from old_target to new_target.
*
* @param lg array of local variables
* @param old_target the old target instruction handle
* @param new_target the new target instruction handle
* @see MethodGen
*/
public void redirectLocalVariables(LocalVariableGen[] lg,
InstructionHandle old_target,
InstructionHandle new_target) {
for(int i=0; i < lg.length; i++) {
InstructionHandle start = lg[i].getStart();
InstructionHandle end = lg[i].getEnd();
if(start == old_target)
lg[i].setStart(new_target);
if(end == old_target)
lg[i].setEnd(new_target);
}
}
/**
* Redirect all references of exception handlers from old_target to new_target.
*
* @param exceptions array of exception handlers
* @param old_target the old target instruction handle
* @param new_target the new target instruction handle
* @see MethodGen
*/
public void redirectExceptionHandlers(CodeExceptionGen[] exceptions,
InstructionHandle old_target,
InstructionHandle new_target) {
for(int i=0; i < exceptions.length; i++) {
if(exceptions[i].getStartPC() == old_target)
exceptions[i].setStartPC(new_target);
if(exceptions[i].getEndPC() == old_target)
exceptions[i].setEndPC(new_target);
if(exceptions[i].getHandlerPC() == old_target)
exceptions[i].setHandlerPC(new_target);
}
}
private ArrayList observers;
/** Add observer for this object.
*/
public void addObserver(InstructionListObserver o) {
if(observers == null)
observers = new ArrayList();
observers.add(o);
}
/** Remove observer for this object.
*/
public void removeObserver(InstructionListObserver o) {
if(observers != null)
observers.remove(o);
}
/** Call notify() method on all observers. This method is not called
* automatically whenever the state has changed, but has to be
* called by the user after he has finished editing the object.
*/
public void update() {
if(observers != null)
for(Iterator e = observers.iterator(); e.hasNext(); )
((InstructionListObserver)e.next()).notify(this);
}
}