/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2011 Eric Lafortune (eric@graphics.cornell.edu)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program 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 for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package proguard.evaluation;
import proguard.evaluation.value.Value;
/**
* This Stack saves additional information with stack elements, to keep track
* of their origins and destinations.
* <p>
* The stack stores a given producer Value along with each Value it stores.
* It then generalizes a given collected Value with the producer Value
* of each Value it loads. The producer Value and the initial collected Value
* can be set; the generalized collected Value can be retrieved.
*
* @author Eric Lafortune
*/
public class TracedStack extends Stack
{
private Value producerValue;
private Stack producerStack;
/**
* Creates a new TracedStack with a given maximum size.
*/
public TracedStack(int maxSize)
{
super(maxSize);
producerStack = new Stack(maxSize);
}
/**
* Creates a new TracedStack that is a copy of the given TracedStack.
*/
public TracedStack(TracedStack tracedStack)
{
super(tracedStack);
producerStack = new Stack(tracedStack.producerStack);
}
/**
* Sets the Value that will be stored along with all push and pop
* instructions.
*/
public void setProducerValue(Value producerValue)
{
this.producerValue = producerValue;
}
/**
* Gets the specified producer Value from the stack, without disturbing it.
* @param index the index of the stack element, counting from the bottom
* of the stack.
* @return the producer value at the specified position.
*/
public Value getBottomProducerValue(int index)
{
return producerStack.getBottom(index);
}
/**
* Sets the specified producer Value on the stack, without disturbing it.
* @param index the index of the stack element, counting from the bottom
* of the stack.
* @param value the producer value to set.
*/
public void setBottomProducerValue(int index, Value value)
{
producerStack.setBottom(index, value);
}
/**
* Gets the specified producer Value from the stack, without disturbing it.
* @param index the index of the stack element, counting from the top
* of the stack.
* @return the producer value at the specified position.
*/
public Value getTopProducerValue(int index)
{
return producerStack.getTop(index);
}
/**
* Sets the specified producer Value on the stack, without disturbing it.
* @param index the index of the stack element, counting from the top
* of the stack.
* @param value the producer value to set.
*/
public void setTopProducerValue(int index, Value value)
{
producerStack.setTop(index, value);
}
// Implementations for Stack.
public void reset(int size)
{
super.reset(size);
producerStack.reset(size);
}
public void copy(TracedStack other)
{
super.copy(other);
producerStack.copy(other.producerStack);
}
public boolean generalize(TracedStack other)
{
return
super.generalize(other) |
producerStack.generalize(other.producerStack);
}
public void clear()
{
super.clear();
producerStack.clear();
}
public void removeTop(int index)
{
super.removeTop(index);
producerStack.removeTop(index);
}
public void push(Value value)
{
super.push(value);
producerPush();
// Account for the extra space required by Category 2 values.
if (value.isCategory2())
{
producerPush();
}
}
public Value pop()
{
Value value = super.pop();
producerPop();
// Account for the extra space required by Category 2 values.
if (value.isCategory2())
{
producerPop();
}
return value;
}
public void pop1()
{
super.pop1();
producerPop();
}
public void pop2()
{
super.pop2();
producerPop();
producerPop();
}
public void dup()
{
super.dup();
producerPop();
producerPush();
producerPush();
}
public void dup_x1()
{
super.dup_x1();
producerPop();
producerPop();
producerPush();
producerPush();
producerPush();
}
public void dup_x2()
{
super.dup_x2();
producerPop();
producerPop();
producerPop();
producerPush();
producerPush();
producerPush();
producerPush();
}
public void dup2()
{
super.dup2();
producerPop();
producerPop();
producerPush();
producerPush();
producerPush();
producerPush();
}
public void dup2_x1()
{
super.dup2_x1();
producerPop();
producerPop();
producerPop();
producerPush();
producerPush();
producerPush();
producerPush();
producerPush();
}
public void dup2_x2()
{
super.dup2_x2();
producerPop();
producerPop();
producerPop();
producerPop();
producerPush();
producerPush();
producerPush();
producerPush();
producerPush();
producerPush();
}
public void swap()
{
super.swap();
producerPop();
producerPop();
producerPush();
producerPush();
}
// Implementations for Object.
public boolean equals(Object object)
{
if (object == null ||
this.getClass() != object.getClass())
{
return false;
}
TracedStack other = (TracedStack)object;
return super.equals(object) &&
this.producerStack.equals(other.producerStack);
}
public int hashCode()
{
return super.hashCode() ^
producerStack.hashCode();
}
public String toString()
{
StringBuffer buffer = new StringBuffer();
for (int index = 0; index < this.size(); index++)
{
Value value = this.values[index];
Value producerValue = producerStack.getBottom(index);
buffer = buffer.append('[')
.append(producerValue == null ? "empty:" : producerValue.toString())
.append(value == null ? "empty" : value.toString())
.append(']');
}
return buffer.toString();
}
// Small utility methods.
private void producerPush()
{
producerStack.push(producerValue);
}
private void producerPop()
{
producerStack.pop();
}
}