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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.
/*
* ProGuardCORE -- library to process Java bytecode.
*
* Copyright (c) 2002-2020 Guardsquare NV
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package proguard.evaluation;
import proguard.evaluation.value.Value;
/**
* This {@link Stack} saves additional information with stack elements, to keep
* track of their origins.
*
* 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, either taking
* into account dup/swap instructions as proper instructions or ignoring them.
*
* @author Eric Lafortune
*/
public class TracedStack extends Stack
{
private Value producerValue;
private Stack producerStack;
private Stack actualProducerStack;
/**
* Creates a new TracedStack with a given maximum size.
*/
public TracedStack(int maxSize)
{
super(maxSize);
producerStack = new Stack(maxSize);
actualProducerStack = 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);
actualProducerStack = new Stack(tracedStack.actualProducerStack);
}
/**
* 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);
}
/**
* Gets the specified actual producer Value from the stack, ignoring
* dup/swap instructions, 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 getBottomActualProducerValue(int index)
{
return actualProducerStack.getBottom(index);
}
/**
* 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);
}
/**
* Gets the specified actual producer Value from the stack, ignoring
* dup/swap instructions, 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 getTopActualProducerValue(int index)
{
return actualProducerStack.getTop(index);
}
// Implementations for Stack.
public void reset(int size)
{
super.reset(size);
producerStack.reset(size);
actualProducerStack.reset(size);
}
public void copy(TracedStack other)
{
super.copy(other);
producerStack.copy(other.producerStack);
actualProducerStack.copy(other.actualProducerStack);
}
public boolean generalize(TracedStack other)
{
return
super.generalize(other) |
producerStack.generalize(other.producerStack) |
actualProducerStack.generalize(other.actualProducerStack);
}
public void clear()
{
super.clear();
producerStack.clear();
actualProducerStack.clear();
}
public void removeTop(int index)
{
super.removeTop(index);
producerStack.removeTop(index);
actualProducerStack.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();
producerStack.pop();
producerStack.push(producerValue);
producerStack.push(producerValue);
actualProducerStack.dup();
}
public void dup_x1()
{
super.dup_x1();
producerStack.pop();
producerStack.pop();
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
actualProducerStack.dup_x1();
}
public void dup_x2()
{
super.dup_x2();
producerStack.pop();
producerStack.pop();
producerStack.pop();
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
actualProducerStack.dup_x2();
}
public void dup2()
{
super.dup2();
producerStack.pop();
producerStack.pop();
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
actualProducerStack.dup2();
}
public void dup2_x1()
{
super.dup2_x1();
producerStack.pop();
producerStack.pop();
producerStack.pop();
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
actualProducerStack.dup2_x1();
}
public void dup2_x2()
{
super.dup2_x2();
producerStack.pop();
producerStack.pop();
producerStack.pop();
producerStack.pop();
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
producerStack.push(producerValue);
actualProducerStack.dup2_x2();
}
public void swap()
{
super.swap();
producerStack.pop();
producerStack.pop();
producerStack.push(producerValue);
producerStack.push(producerValue);
actualProducerStack.swap();
}
// 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) &&
this.actualProducerStack.equals(other.actualProducerStack);
}
public int hashCode()
{
return super.hashCode() ^
producerStack.hashCode() ^
actualProducerStack.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);
Value actualProducerValue = actualProducerStack.getBottom(index);
buffer = buffer.append('[')
.append(producerValue == null ? "empty:" :
producerValue.equals(actualProducerValue) ? producerValue.toString() :
producerValue.toString() + actualProducerValue.toString())
.append(value == null ? "empty" : value.toString())
.append(']');
}
return buffer.toString();
}
// Small utility methods.
private void producerPush()
{
producerStack.push(producerValue);
actualProducerStack.push(producerValue);
}
private void producerPop()
{
producerStack.pop();
actualProducerStack.pop();
}
}
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