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JQF: Feedback-directed Quickcheck for Java - Guided fuzzing interface
/*
* Copyright (c) 2017-2018 The Regents of the University of California
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR 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 USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package edu.berkeley.cs.jqf.fuzz.ei;
import java.util.ArrayList;
import java.util.Arrays;
import edu.berkeley.cs.jqf.fuzz.util.Counter;
import edu.berkeley.cs.jqf.fuzz.util.NonZeroCachingCounter;
import edu.berkeley.cs.jqf.instrument.tracing.events.CallEvent;
import edu.berkeley.cs.jqf.instrument.tracing.events.ReturnEvent;
import edu.berkeley.cs.jqf.instrument.tracing.events.TraceEvent;
/**
* A mutable state representing the current call stack with prefix counts,
* used to compute light-weight execution indexes.
*
* @see ExecutionIndex
*
* @author Rohan Padhye
*/
public class ExecutionIndexingState {
private final int COUNTER_SIZE = 6151;
private final int MAX_SUPPORTED_DEPTH = 1024; // Nothing deeper than this
private int depth = 0;
private ArrayList stackOfCounters = new ArrayList<>();
private int[] rollingIndex = new int[2*MAX_SUPPORTED_DEPTH];
public ExecutionIndexingState() {
// Create a counter for depth = 0
stackOfCounters.add(new NonZeroCachingCounter(COUNTER_SIZE));
}
public void pushCall(CallEvent e) {
// Increment counter for call-site (note: this is subject to hash collisions)
int count = stackOfCounters.get(depth).increment(e.getIid());
// Add to rolling execution index
rollingIndex[2*depth] = e.getIid();
rollingIndex[2*depth + 1] = count;
// Increment depth
depth++;
// Ensure that we do not go very deep
if (depth >= MAX_SUPPORTED_DEPTH) {
throw new StackOverflowError("Very deep stack; cannot compute execution index");
}
// Push a new counter if it does not exist
if (depth >= stackOfCounters.size()) {
stackOfCounters.add(new NonZeroCachingCounter(COUNTER_SIZE));
}
}
public void popReturn(ReturnEvent e) {
// Clear the top-of-stack
stackOfCounters.get(depth).clear();
// Decrement depth
depth--;
assert (depth >= 0);
}
public ExecutionIndex getExecutionIndex(TraceEvent e) {
// Increment counter for event (note: this is subject to hash collisions)
int count = stackOfCounters.get(depth).increment(e.getIid());
// Add to rolling execution index
rollingIndex[2*depth] = e.getIid();
rollingIndex[2*depth + 1] = count;
// Snapshot the rolling index
int size = 2*(depth+1); // 2 integers for each depth value
int[] ei = Arrays.copyOf(rollingIndex, size);
// Create an execution index
return new ExecutionIndex(ei);
}
}