/**
* Instantiates a new CPA algorithm with a backward location analysis, a default backward
* transformer factory and worklist suitable for an analysis of a complete and already
* reconstructed control flow automaton.
*
* @param program The program object
* @param cpas The list of backward analyses to be performed
*/
public static CPAAlgorithm createBackwardAlgorithm(
Program program, ConfigurableProgramAnalysis... cpas) {
ConfigurableProgramAnalysis cpa =
new CompositeProgramAnalysis(new BackwardLocationAnalysis(), cpas);
return new CPAAlgorithm(
program,
cpa,
new ReverseCFATransformerFactory(program.getCFA()),
new FastSet<AbstractState>());
}
@Override
public void run() {
Runtime runtime = Runtime.getRuntime();
// Jakstab Algorithm
System.out.println("Starting CPA algorithm.");
AbstractState start = cpa.initStartState(transformerFactory.getInitialLocation());
worklist.add(start);
reached.add(start);
if (art != null) art.setRoot(start);
// Set up precisions
Precision precision = cpa.initPrecision(transformerFactory.getInitialLocation(), null);
Map<Location, Precision> precisionMap = new HashMap<Location, Precision>();
precisionMap.put(start.getLocation(), precision);
int steps = 0;
statesVisited = 0;
final int stepThreshold = 1000;
long startTime = System.currentTimeMillis();
long lastSteps = 0;
long lastTime = 0;
while (!worklist.isEmpty() && !stop && (!failFast || isSound())) {
statesVisited++;
if (++steps == stepThreshold) {
// Helps limit memory usage
long now = System.currentTimeMillis();
System.gc();
long gcTime = System.currentTimeMillis() - now;
logger.debug("Time for GC: " + gcTime + "ms");
now = System.currentTimeMillis();
long duration = Math.max(1, now - lastTime);
long speed = (1000L * (statesVisited - lastSteps) / duration);
// speed = Math.min(speed, 1000);
logger.warn(
"*** Reached "
+ reached.size()
+ " states, processed "
+ statesVisited
+ " states after "
+ (now - startTime)
+ "ms, at "
+ speed
+ " states/second"
+ (transformerFactory instanceof ResolvingTransformerFactory
? ", " + program.getInstructionCount() + " instructions."
: "."));
logger.info(
String.format(
" Allocated heap memory: %.2f MByte",
(runtime.totalMemory() - runtime.freeMemory()) / (1024.0 * 1024.0)));
steps = 0;
// StatsPlotter.plot((now - startTime) + "\t" + statesVisited
// +"\t" + program.getInstructionCount() + "\t" + gcTime + "\t"
// + speed);
lastSteps = statesVisited;
lastTime = now;
if (Options.timeout.getValue() > 0
&& (System.currentTimeMillis() - startTime > Options.timeout.getValue() * 1000)) {
logger.error("Timeout after " + Options.timeout.getValue() + "s!");
stop = true;
}
}
// We need the state before precision refinement for building the
// ART
AbstractState unadjustedState = worklist.pick();
/*
* if (unadjustedState.getLocation().getAddress().toString().equals(
* "0x00401189") //||
* unadjustedState.getLocation().getAddress().toString
* ().equals("0x0040119b") ||
* unadjustedState.getLocation().getAddress
* ().toString().equals("0x00401078") ||
* unadjustedState.getLocation(
* ).getAddress().toString().equals("0x0040100a") )
* System.out.println("Debug " +
* unadjustedState.getLocation().getAddress().toString());
*/
precision = precisionMap.get(unadjustedState.getLocation());
Pair<AbstractState, Precision> pair = cpa.prec(unadjustedState, precision, reached);
// Warning: The refined a is not stored in "reached", only used for
// successor calculation
AbstractState a = pair.getLeft();
/*
* CompositeState a1 = (CompositeState) a; BasedNumberValuation a2 =
* (BasedNumberValuation)a1.getComponent(1); if
* (a2.getStore().isTop()) System.out.println("Debug TOP Value");
*/
precision = pair.getRight();
precisionMap.put(a.getLocation(), precision);
// logger.debug("Picked from worklist: " + a.getIdentifier());
// getTransformers() and post() might throw exceptions
try {
// For each outgoing edge
// if (a.isTop())
// System.out.println("Debug TOP");
/*
* if
* (a.getLocation().getAddress().toString().equals("0x004106cd")
* ||
* (a.getLocation().getAddress().toString().equals("0x00410498")
* && a.getLocation().getIndex() >= 0))
* System.out.println("Debug Transformer Factory:" +
* a.getLocation().getAddress().toString());
*/
// Set<CFAEdge> s = transformerFactory.getTransformers(a);
// System.out.println("Debug Transformer Factory:" +
// a.getLocation().getAddress().toString());
for (CFAEdge cfaEdge : transformerFactory.getTransformers(a)) {
Precision targetPrecision = precisionMap.get(cfaEdge.getTarget());
if (targetPrecision == null) {
targetPrecision = cpa.initPrecision(cfaEdge.getTarget(), cfaEdge.getTransformer());
precisionMap.put(cfaEdge.getTarget(), targetPrecision);
}
// Prefix everything by current location for easier
// debugging
// Logger.setGlobalPrefix(cfaEdge.getSource().toString());
// if
// (cfaEdge.getSource().getAddress().toString().equals("0x00401027")
// &&
// cfaEdge.getTarget().getAddress().toString().equals("0x0040102e"))
// System.out.println("Debug Edge");
// Calculate the set of abstract successors
Set<AbstractState> successors = cpa.post(a, cfaEdge, targetPrecision);
if (successors.isEmpty()) {
logger.debug("No successors along edge " + cfaEdge + ", reached halt?");
continue;
}
// logger.debug("via edge " + cfaEdge.toString() + " " +
// successors.size() + " successors.");
// Process every successor
for (AbstractState succ : successors) {
// logger.debug("Processing new post state: " +
// succ.getIdentifier());
// Try to merge the new state with an existing one
Set<AbstractState> statesToRemove = new FastSet<AbstractState>();
Set<AbstractState> statesToAdd = new FastSet<AbstractState>();
for (AbstractState r : reached.where(0, ((CompositeState) succ).getComponent(0))) {
AbstractState merged = cpa.merge(succ, r, targetPrecision);
if (!merged.equals(r)) {
// logger.debug("Merge of " +
// succ.getIdentifier() + " and " +
// r.getIdentifier() + " produced new state " +
// merged.getIdentifier());
statesToRemove.add(r);
statesToAdd.add(merged);
}
}
// replace the old state in worklist and reached with
// the merged version
for (AbstractState r : statesToRemove) {
reached.remove(r);
worklist.remove(r);
// art.remove(r);
}
for (AbstractState r : statesToAdd) {
// Only add r to the worklist if it hasn't been
// reached yet
if (reached.add(r)) {
worklist.add(r);
if (art != null) art.addChild(unadjustedState, r);
}
}
// if not stopped add to worklist
if (!cpa.stop(succ, reached, targetPrecision)
|| this.program.checkSMPos(((CompositeState) succ).getLocation().getAddress())) {
worklist.add(succ);
reached.add(succ);
if (art != null) art.addChild(unadjustedState, succ);
}
}
// end for each outgoing edge
}
} catch (StateException e) {
if (e.getState() == null) {
e.setState(a);
}
if (art != null && !unadjustedState.equals(e.getState()))
art.addChild(unadjustedState, e.getState());
throw e;
}
}
long endTime = System.currentTimeMillis();
if (endTime - startTime > 0) {
logger.info(
"Processed "
+ statesVisited
+ " states at "
+ (1000L * statesVisited / (endTime - startTime))
+ " states/second");
logger.info(
String.format(
"Allocated heap memory: %.2f MByte",
(runtime.totalMemory() - runtime.freeMemory()) / (1024.0 * 1024.0)));
}
completed = worklist.isEmpty();
}