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WALA/com.ibm.wala.core/src/com/ibm/wala/ipa/callgraph/propagation/PropagationSystem.java

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/*******************************************************************************
* Copyright (c) 2002 - 2006 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package com.ibm.wala.ipa.callgraph.propagation;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.ibm.wala.classLoader.ArrayClass;
import com.ibm.wala.classLoader.IClass;
import com.ibm.wala.fixedpoint.impl.DefaultFixedPointSolver;
import com.ibm.wala.fixedpoint.impl.Worklist;
import com.ibm.wala.fixpoint.AbstractOperator;
import com.ibm.wala.fixpoint.AbstractStatement;
import com.ibm.wala.fixpoint.IFixedPointSystem;
import com.ibm.wala.fixpoint.IVariable;
import com.ibm.wala.fixpoint.UnaryOperator;
import com.ibm.wala.fixpoint.UnaryStatement;
import com.ibm.wala.ipa.callgraph.CallGraph;
import com.ibm.wala.ipa.callgraph.propagation.PropagationCallGraphBuilder.FilterOperator;
import com.ibm.wala.ipa.cha.ClassHierarchyException;
import com.ibm.wala.ipa.cha.ClassHierarchyWarning;
import com.ibm.wala.types.TypeReference;
import com.ibm.wala.util.collections.HashMapFactory;
import com.ibm.wala.util.collections.HashSetFactory;
import com.ibm.wala.util.collections.Iterator2Collection;
import com.ibm.wala.util.collections.MapUtil;
import com.ibm.wala.util.debug.Assertions;
import com.ibm.wala.util.debug.VerboseAction;
import com.ibm.wala.util.graph.Graph;
import com.ibm.wala.util.graph.NumberedGraph;
import com.ibm.wala.util.heapTrace.HeapTracer;
import com.ibm.wala.util.intset.IntIterator;
import com.ibm.wala.util.intset.IntSet;
import com.ibm.wala.util.intset.IntSetAction;
import com.ibm.wala.util.intset.IntSetUtil;
import com.ibm.wala.util.intset.MutableIntSet;
import com.ibm.wala.util.intset.MutableMapping;
import com.ibm.wala.util.ref.ReferenceCleanser;
import com.ibm.wala.util.warnings.Warnings;
/**
* System of constraints that define propagation for call graph construction
*/
public class PropagationSystem extends DefaultFixedPointSolver<PointsToSetVariable> {
private final static boolean DEBUG = false;
private final static boolean DEBUG_MEMORY = false;
private static int DEBUG_MEM_COUNTER = 0;
private final static int DEBUG_MEM_INTERVAL = 5;
/**
* object that tracks points-to sets
*/
protected final PointsToMap pointsToMap = new PointsToMap();
/**
* Implementation of the underlying dataflow graph
*/
private final PropagationGraph flowGraph = new PropagationGraph();
/**
* bijection from InstanceKey &lt;=&gt; Integer
*/
protected final MutableMapping<InstanceKey> instanceKeys = MutableMapping.make();
/**
* A mapping from IClass -> MutableSharedBitVectorIntSet The range represents the instance keys that correspond to a given class.
* This mapping is used to filter sets based on declared types; e.g., in cast constraints
*/
final private Map<IClass, MutableIntSet> class2InstanceKey = HashMapFactory.make();
/**
* An abstraction of the pointer analysis result
*/
private PointerAnalysis<InstanceKey> pointerAnalysis;
/**
* Meta-data regarding how pointers are modelled.
*/
private final PointerKeyFactory pointerKeyFactory;
/**
* Meta-data regarding how instances are modelled.
*/
private final InstanceKeyFactory instanceKeyFactory;
/**
* When doing unification, we must also updated the fixed sets in unary side effects.
*
* This maintains a map from PointsToSetVariable -> Set<UnarySideEffect>
*/
final private Map<PointsToSetVariable, Set<UnarySideEffect>> fixedSetMap = HashMapFactory.make();
/**
* Governing call graph;
*/
protected final CallGraph cg;
private int verboseInterval = DEFAULT_VERBOSE_INTERVAL;
private int periodicMaintainInterval = DEFAULT_PERIODIC_MAINTENANCE_INTERVAL;
public PropagationSystem(CallGraph cg, PointerKeyFactory pointerKeyFactory, InstanceKeyFactory instanceKeyFactory) {
if (cg == null) {
throw new IllegalArgumentException("null cg");
}
this.cg = cg;
this.pointerKeyFactory = pointerKeyFactory;
this.instanceKeyFactory = instanceKeyFactory;
// when doing paranoid checking of points-to sets, code in PointsToSetVariable needs to know about the instance key
// mapping
if (PointsToSetVariable.PARANOID) {
PointsToSetVariable.instanceKeys = instanceKeys;
}
}
/**
* @return an object which encapsulates the pointer analysis result
*/
public PointerAnalysis<InstanceKey> makePointerAnalysis(PropagationCallGraphBuilder builder) {
return new PointerAnalysisImpl(builder, cg, pointsToMap, instanceKeys, pointerKeyFactory, instanceKeyFactory);
}
protected void registerFixedSet(PointsToSetVariable p, UnarySideEffect s) {
Set<UnarySideEffect> set = MapUtil.findOrCreateSet(fixedSetMap, p);
set.add(s);
}
protected void updateSideEffects(PointsToSetVariable p, PointsToSetVariable rep) {
Set<UnarySideEffect> set = fixedSetMap.get(p);
if (set != null) {
for (Iterator it = set.iterator(); it.hasNext();) {
UnarySideEffect s = (UnarySideEffect) it.next();
s.replaceFixedSet(rep);
}
Set<UnarySideEffect> s2 = MapUtil.findOrCreateSet(fixedSetMap, rep);
s2.addAll(set);
fixedSetMap.remove(p);
}
}
/**
* Keep this method private .. this returns the actual backing set for the class, which we do not want to expose to clients.
*/
private MutableIntSet findOrCreateSparseSetForClass(IClass klass) {
assert klass.getReference() != TypeReference.JavaLangObject;
MutableIntSet result = class2InstanceKey.get(klass);
if (result == null) {
result = IntSetUtil.getDefaultIntSetFactory().make();
class2InstanceKey.put(klass, result);
}
return result;
}
/**
* @return a set of integers representing the instance keys that correspond to a given class. This method creates a new set, which
* the caller may bash at will.
*/
MutableIntSet cloneInstanceKeysForClass(IClass klass) {
assert klass.getReference() != TypeReference.JavaLangObject;
MutableIntSet set = class2InstanceKey.get(klass);
if (set == null) {
return IntSetUtil.getDefaultIntSetFactory().make();
} else {
// return a copy.
return IntSetUtil.getDefaultIntSetFactory().makeCopy(set);
}
}
/**
* @return a set of integers representing the instance keys that correspond to a given class, or null if there are none.
* @throws IllegalArgumentException if klass is null
*/
public IntSet getInstanceKeysForClass(IClass klass) {
if (klass == null) {
throw new IllegalArgumentException("klass is null");
}
assert klass != klass.getClassHierarchy().getRootClass();
return class2InstanceKey.get(klass);
}
/**
* @return the instance key numbered with index i
*/
public InstanceKey getInstanceKey(int i) {
return instanceKeys.getMappedObject(i);
}
public int getInstanceIndex(InstanceKey ik) {
return instanceKeys.getMappedIndex(ik);
}
/**
* TODO: optimize; this may be inefficient;
*
* @return an List of instance keys corresponding to the integers in a set
*/
List<InstanceKey> getInstances(IntSet set) {
LinkedList<InstanceKey> result = new LinkedList<InstanceKey>();
for (IntIterator it = set.intIterator(); it.hasNext();) {
int j = it.next();
result.add(getInstanceKey(j));
}
return result;
}
@Override
protected void initializeVariables() {
// don't have to do anything; all variables initialized
// by default to TOP (the empty set);
}
/**
* record that a particular points-to-set is represented implicitly.
*/
public void recordImplicitPointsToSet(PointerKey key) {
if (key == null) {
throw new IllegalArgumentException("null key");
}
if (key instanceof LocalPointerKey) {
LocalPointerKey lpk = (LocalPointerKey) key;
if (lpk.isParameter()) {
System.err.println("------------------ ERROR:");
System.err.println("LocalPointerKey: " + lpk);
System.err.println("Constant? " + lpk.getNode().getIR().getSymbolTable().isConstant(lpk.getValueNumber()));
System.err.println(" -- IR:");
System.err.println(lpk.getNode().getIR());
Assertions.UNREACHABLE("How can parameter be implicit?");
}
}
pointsToMap.recordImplicit(key);
}
/**
* If key is unified, returns the representative
*
* @param key
* @return the dataflow variable that tracks the points-to set for key
*/
public PointsToSetVariable findOrCreatePointsToSet(PointerKey key) {
if (key == null) {
throw new IllegalArgumentException("null key");
}
if (pointsToMap.isImplicit(key)) {
System.err.println("Did not expect to findOrCreatePointsToSet for implicitly represented PointerKey");
System.err.println(key);
Assertions.UNREACHABLE();
}
PointsToSetVariable result = pointsToMap.getPointsToSet(key);
if (result == null) {
result = new PointsToSetVariable(key);
pointsToMap.put(key, result);
} else {
// check that the filter for this variable remains unique
if (!pointsToMap.isUnified(key) && key instanceof FilteredPointerKey) {
PointerKey pk = result.getPointerKey();
if (!(pk instanceof FilteredPointerKey)) {
// add a filter for all future evaluations.
// this is tricky, but the logic is OK .. any constraints that need
// the filter will see it ...
// CALLERS MUST BE EXTRA CAREFUL WHEN DEALING WITH UNIFICATION!
result.setPointerKey(key);
pk = key;
}
FilteredPointerKey fpk = (FilteredPointerKey) pk;
assert fpk != null;
assert key != null;
if (fpk.getTypeFilter() == null) {
Assertions.UNREACHABLE("fpk.getTypeFilter() is null");
}
if (!fpk.getTypeFilter().equals(((FilteredPointerKey) key).getTypeFilter())) {
Assertions.UNREACHABLE("Cannot use filter " + ((FilteredPointerKey) key).getTypeFilter() + " for " + key
+ ": previously created different filter " + fpk.getTypeFilter());
}
}
}
return result;
}
public int findOrCreateIndexForInstanceKey(InstanceKey key) {
int result = instanceKeys.getMappedIndex(key);
if (result == -1) {
result = instanceKeys.add(key);
}
if (DEBUG) {
System.err.println("getIndexForInstanceKey " + key + " " + result);
}
return result;
}
/**
* NB: this is idempotent ... if the given constraint exists, it will not be added to the system; however, this will be more
* expensive since it must check if the constraint pre-exits.
*
* @return true iff the system changes
*/
public boolean newConstraint(PointerKey lhs, UnaryOperator<PointsToSetVariable> op, PointerKey rhs) {
if (lhs == null) {
throw new IllegalArgumentException("null lhs");
}
if (op == null) {
throw new IllegalArgumentException("op null");
}
if (rhs == null) {
throw new IllegalArgumentException("rhs null");
}
if (DEBUG) {
System.err.println("Add constraint A: " + lhs + " " + op + " " + rhs);
}
PointsToSetVariable L = findOrCreatePointsToSet(lhs);
PointsToSetVariable R = findOrCreatePointsToSet(rhs);
if (op instanceof FilterOperator) {
// we do not want to revert the lhs to pre-transitive form;
// we instead want to check in the outer loop of the pre-transitive
// solver if the value of L changes.
pointsToMap.recordTransitiveRoot(L.getPointerKey());
if (!(L.getPointerKey() instanceof FilteredPointerKey)) {
Assertions.UNREACHABLE("expected filtered lhs " + L.getPointerKey() + " " + L.getPointerKey().getClass() + " " + lhs + " "
+ lhs.getClass());
}
}
return newStatement(L, op, R, true, true);
}
public boolean newConstraint(PointerKey lhs, AbstractOperator<PointsToSetVariable> op, PointerKey rhs) {
if (lhs == null) {
throw new IllegalArgumentException("lhs null");
}
if (op == null) {
throw new IllegalArgumentException("op null");
}
if (rhs == null) {
throw new IllegalArgumentException("rhs null");
}
if (DEBUG) {
System.err.println("Add constraint A: " + lhs + " " + op + " " + rhs);
}
assert !pointsToMap.isUnified(lhs);
assert !pointsToMap.isUnified(rhs);
PointsToSetVariable L = findOrCreatePointsToSet(lhs);
PointsToSetVariable R = findOrCreatePointsToSet(rhs);
return newStatement(L, op, new PointsToSetVariable[] { R }, true, true);
}
public boolean newConstraint(PointerKey lhs, AbstractOperator<PointsToSetVariable> op, PointerKey rhs1, PointerKey rhs2) {
if (lhs == null) {
throw new IllegalArgumentException("null lhs");
}
if (op == null) {
throw new IllegalArgumentException("null op");
}
if (rhs1 == null) {
throw new IllegalArgumentException("null rhs1");
}
if (rhs2 == null) {
throw new IllegalArgumentException("null rhs2");
}
if (DEBUG) {
System.err.println("Add constraint A: " + lhs + " " + op + " " + rhs1 + ", " + rhs2);
}
assert !pointsToMap.isUnified(lhs);
assert !pointsToMap.isUnified(rhs1);
assert !pointsToMap.isUnified(rhs2);
PointsToSetVariable L = findOrCreatePointsToSet(lhs);
PointsToSetVariable R1 = findOrCreatePointsToSet(rhs1);
PointsToSetVariable R2 = findOrCreatePointsToSet(rhs2);
return newStatement(L, op, R1, R2, true, true);
}
/**
* @return true iff the system changes
*/
public boolean newFieldWrite(PointerKey lhs, UnaryOperator<PointsToSetVariable> op, PointerKey rhs, PointerKey container) {
return newConstraint(lhs, op, rhs);
}
/**
* @return true iff the system changes
*/
public boolean newFieldRead(PointerKey lhs, UnaryOperator<PointsToSetVariable> op, PointerKey rhs, PointerKey container) {
return newConstraint(lhs, op, rhs);
}
/**
* @return true iff the system changes
*/
public boolean newConstraint(PointerKey lhs, InstanceKey value) {
if (DEBUG) {
System.err.println("Add constraint B: " + lhs + " U= " + value);
}
pointsToMap.recordTransitiveRoot(lhs);
// we don't actually add a constraint.
// instead, we immediately add the value to the points-to set.
// This works since the solver is monotonic with TOP = {}
PointsToSetVariable L = findOrCreatePointsToSet(lhs);
int index = findOrCreateIndexForInstanceKey(value);
if (L.contains(index)) {
// a no-op
return false;
} else {
L.add(index);
// also register that we have an instanceKey for the klass
assert value.getConcreteType() != null;
if (!value.getConcreteType().getReference().equals(TypeReference.JavaLangObject)) {
registerInstanceOfClass(value.getConcreteType(), index);
}
// we'd better update the worklist appropriately
// if graphNodeId == -1, then there are no equations that use this
// variable.
if (L.getGraphNodeId() > -1) {
changedVariable(L);
}
return true;
}
}
/**
* Record that we have a new instanceKey for a given declared type.
*/
private void registerInstanceOfClass(IClass klass, int index) {
if (DEBUG) {
System.err.println("registerInstanceOfClass " + klass + " " + index);
}
assert !klass.getReference().equals(TypeReference.JavaLangObject);
try {
IClass T = klass;
registerInstanceWithAllSuperclasses(index, T);
registerInstanceWithAllInterfaces(klass, index);
if (klass.isArrayClass()) {
ArrayClass aClass = (ArrayClass) klass;
int dim = aClass.getDimensionality();
registerMultiDimArraysForArrayOfObjectTypes(dim, index, aClass);
IClass elementClass = aClass.getInnermostElementClass();
if (elementClass != null) {
registerArrayInstanceWithAllSuperclassesOfElement(index, elementClass, dim);
registerArrayInstanceWithAllInterfacesOfElement(index, elementClass, dim);
}
}
} catch (ClassHierarchyException e) {
Warnings.add(ClassHierarchyWarning.create(e.getMessage()));
}
}
private int registerMultiDimArraysForArrayOfObjectTypes(int dim, int index, ArrayClass aClass) {
for (int i = 1; i < dim; i++) {
TypeReference jlo = makeArray(TypeReference.JavaLangObject, i);
IClass jloClass = null;
jloClass = aClass.getClassLoader().lookupClass(jlo.getName());
MutableIntSet set = findOrCreateSparseSetForClass(jloClass);
set.add(index);
}
return dim;
}
private void registerArrayInstanceWithAllInterfacesOfElement(int index, IClass elementClass, int dim) {
Collection ifaces = null;
ifaces = elementClass.getAllImplementedInterfaces();
for (Iterator it = ifaces.iterator(); it.hasNext();) {
IClass I = (IClass) it.next();
TypeReference iArrayRef = makeArray(I.getReference(), dim);
IClass iArrayClass = null;
iArrayClass = I.getClassLoader().lookupClass(iArrayRef.getName());
MutableIntSet set = findOrCreateSparseSetForClass(iArrayClass);
set.add(index);
if (DEBUG) {
System.err.println("dense filter for interface " + iArrayClass + " " + set);
}
}
}
private static TypeReference makeArray(TypeReference element, int dim) {
TypeReference iArrayRef = element;
for (int i = 0; i < dim; i++) {
iArrayRef = TypeReference.findOrCreateArrayOf(iArrayRef);
}
return iArrayRef;
}
private void registerArrayInstanceWithAllSuperclassesOfElement(int index, IClass elementClass, int dim) {
IClass T;
// register the array with each supertype of the element class
T = elementClass.getSuperclass();
while (T != null) {
TypeReference tArrayRef = makeArray(T.getReference(), dim);
IClass tArrayClass = null;
tArrayClass = T.getClassLoader().lookupClass(tArrayRef.getName());
MutableIntSet set = findOrCreateSparseSetForClass(tArrayClass);
set.add(index);
if (DEBUG) {
System.err.println("dense filter for class " + tArrayClass + " " + set);
}
T = T.getSuperclass();
}
}
/**
* @param klass
* @param index
* @throws ClassHierarchyException
*/
private void registerInstanceWithAllInterfaces(IClass klass, int index) throws ClassHierarchyException {
Collection ifaces = klass.getAllImplementedInterfaces();
for (Iterator it = ifaces.iterator(); it.hasNext();) {
IClass I = (IClass) it.next();
MutableIntSet set = findOrCreateSparseSetForClass(I);
set.add(index);
if (DEBUG) {
System.err.println("dense filter for interface " + I + " " + set);
}
}
}
/**
* @param index
* @param T
* @throws ClassHierarchyException
*/
private void registerInstanceWithAllSuperclasses(int index, IClass T) throws ClassHierarchyException {
while (T != null && !T.getReference().equals(TypeReference.JavaLangObject)) {
MutableIntSet set = findOrCreateSparseSetForClass(T);
set.add(index);
if (DEBUG) {
System.err.println("dense filter for class " + T + " " + set);
}
T = T.getSuperclass();
}
}
public void newSideEffect(UnaryOperator<PointsToSetVariable> op, PointerKey arg0) {
if (arg0 == null) {
throw new IllegalArgumentException("null arg0");
}
if (DEBUG) {
System.err.println("add constraint D: " + op + " " + arg0);
}
assert !pointsToMap.isUnified(arg0);
PointsToSetVariable v1 = findOrCreatePointsToSet(arg0);
newStatement(null, op, v1, true, true);
}
public void newSideEffect(AbstractOperator<PointsToSetVariable> op, PointerKey[] arg0) {
if (arg0 == null) {
throw new IllegalArgumentException("null arg0");
}
if (DEBUG) {
System.err.println("add constraint D: " + op + " " + Arrays.toString(arg0));
}
PointsToSetVariable[] vs = new PointsToSetVariable[ arg0.length ];
for(int i = 0; i < arg0.length; i++) {
assert !pointsToMap.isUnified(arg0[i]);
vs[i] = findOrCreatePointsToSet(arg0[i]);
}
newStatement(null, op, vs, true, true);
}
public void newSideEffect(AbstractOperator<PointsToSetVariable> op, PointerKey arg0, PointerKey arg1) {
if (DEBUG) {
System.err.println("add constraint D: " + op + " " + arg0);
}
assert !pointsToMap.isUnified(arg0);
assert !pointsToMap.isUnified(arg1);
PointsToSetVariable v1 = findOrCreatePointsToSet(arg0);
PointsToSetVariable v2 = findOrCreatePointsToSet(arg1);
newStatement(null, op, v1, v2, true, true);
}
@Override
protected void initializeWorkList() {
addAllStatementsToWorkList();
}
/**
* @return an object that encapsulates the pointer analysis results
*/
public PointerAnalysis<InstanceKey> extractPointerAnalysis(PropagationCallGraphBuilder builder) {
if (pointerAnalysis == null) {
pointerAnalysis = makePointerAnalysis(builder);
}
return pointerAnalysis;
}
@Override
public void performVerboseAction() {
super.performVerboseAction();
if (DEBUG_MEMORY) {
DEBUG_MEM_COUNTER++;
if (DEBUG_MEM_COUNTER % DEBUG_MEM_INTERVAL == 0) {
DEBUG_MEM_COUNTER = 0;
ReferenceCleanser.clearSoftCaches();
System.err.println(flowGraph.spaceReport());
System.err.println("Analyze leaks..");
HeapTracer.traceHeap(Collections.singleton(this), true);
System.err.println("done analyzing leaks");
}
}
if (getFixedPointSystem() instanceof VerboseAction) {
((VerboseAction) getFixedPointSystem()).performVerboseAction();
}
if (!workList.isEmpty()) {
AbstractStatement s = workList.takeStatement();
System.err.println(printRHSInstances(s));
workList.insertStatement(s);
System.err.println("CGNodes: " + cg.getNumberOfNodes());
}
}
private String printRHSInstances(AbstractStatement s) {
if (s instanceof UnaryStatement) {
UnaryStatement u = (UnaryStatement) s;
PointsToSetVariable rhs = (PointsToSetVariable) u.getRightHandSide();
IntSet value = rhs.getValue();
final int[] topFive = new int[5];
value.foreach(new IntSetAction() {
@Override
public void act(int x) {
for (int i = 0; i < 4; i++) {
topFive[i] = topFive[i + 1];
}
topFive[4] = x;
}
});
StringBuffer result = new StringBuffer();
for (int i = 0; i < 5; i++) {
int p = topFive[i];
if (p != 0) {
InstanceKey ik = getInstanceKey(p);
result.append(p).append(" ").append(ik).append("\n");
}
}
return result.toString();
} else {
return s.getClass().toString();
}
}
@Override
public IFixedPointSystem<PointsToSetVariable> getFixedPointSystem() {
return flowGraph;
}
/*
* @see com.ibm.wala.ipa.callgraph.propagation.HeapModel#iteratePointerKeys()
*/
public Iterator<PointerKey> iteratePointerKeys() {
return pointsToMap.iterateKeys();
}
/**
* warning: this is _real_ slow; don't use it anywhere performance critical
*/
public int getNumberOfPointerKeys() {
return pointsToMap.getNumberOfPointerKeys();
}
/**
* Use with care.
*/
Worklist getWorklist() {
return workList;
}
public Iterator<AbstractStatement> getStatementsThatUse(PointsToSetVariable v) {
return flowGraph.getStatementsThatUse(v);
}
public Iterator<AbstractStatement> getStatementsThatDef(PointsToSetVariable v) {
return flowGraph.getStatementsThatDef(v);
}
public NumberedGraph<PointsToSetVariable> getAssignmentGraph() {
return flowGraph.getAssignmentGraph();
}
public Graph<PointsToSetVariable> getFilterAsssignmentGraph() {
return flowGraph.getFilterAssignmentGraph();
}
/**
* NOTE: do not use this method unless you really know what you are doing. Functionality is fragile and may not work in the
* future.
*/
public Graph<PointsToSetVariable> getFlowGraphIncludingImplicitConstraints() {
return flowGraph.getFlowGraphIncludingImplicitConstraints();
}
/**
*
*/
public void revertToPreTransitive() {
pointsToMap.revertToPreTransitive();
}
public Iterator getTransitiveRoots() {
return pointsToMap.getTransitiveRoots();
}
public boolean isTransitiveRoot(PointerKey key) {
return pointsToMap.isTransitiveRoot(key);
}
@Override
protected void periodicMaintenance() {
super.periodicMaintenance();
ReferenceCleanser.clearSoftCaches();
}
@Override
public int getVerboseInterval() {
return verboseInterval;
}
/**
* @param verboseInterval The verboseInterval to set.
*/
public void setVerboseInterval(int verboseInterval) {
this.verboseInterval = verboseInterval;
}
@Override
public int getPeriodicMaintainInterval() {
return periodicMaintainInterval;
}
/**
* @param periodicMaintainInteval
*/
public void setPeriodicMaintainInterval(int periodicMaintainInteval) {
this.periodicMaintainInterval = periodicMaintainInteval;
}
/**
* Unify the points-to-sets for the variables identified by the set s
*
* @param s numbers of points-to-set variables
* @throws IllegalArgumentException if s is null
*/
public void unify(IntSet s) {
if (s == null) {
throw new IllegalArgumentException("s is null");
}
// cache the variables represented
HashSet<PointsToSetVariable> cache = HashSetFactory.make(s.size());
for (IntIterator it = s.intIterator(); it.hasNext();) {
int i = it.next();
cache.add(pointsToMap.getPointsToSet(i));
}
// unify the variables
pointsToMap.unify(s);
int rep = pointsToMap.getRepresentative(s.intIterator().next());
// clean up the equations
updateEquationsForUnification(cache, rep);
// special logic to clean up side effects
updateSideEffectsForUnification(cache, rep);
}
/**
* Update side effect after unification
*
* @param s set of PointsToSetVariables that have been unified
* @param rep number of the representative variable for the unified set.
*/
private void updateSideEffectsForUnification(HashSet<PointsToSetVariable> s, int rep) {
PointsToSetVariable pRef = pointsToMap.getPointsToSet(rep);
for (Iterator<PointsToSetVariable> it = s.iterator(); it.hasNext();) {
PointsToSetVariable p = it.next();
updateSideEffects(p, pRef);
}
}
/**
* Update equation def/uses after unification
*
* @param s set of PointsToSetVariables that have been unified
* @param rep number of the representative variable for the unified set.
*/
@SuppressWarnings("unchecked")
private void updateEquationsForUnification(HashSet<PointsToSetVariable> s, int rep) {
PointsToSetVariable pRef = pointsToMap.getPointsToSet(rep);
for (Iterator<PointsToSetVariable> it = s.iterator(); it.hasNext();) {
PointsToSetVariable p = it.next();
if (p != pRef) {
// pRef is the representative for p.
// be careful: cache the defs before mucking with the underlying system
for (Iterator d = Iterator2Collection.toSet(getStatementsThatDef(p)).iterator(); d.hasNext();) {
AbstractStatement as = (AbstractStatement) d.next();
if (as instanceof AssignEquation) {
AssignEquation assign = (AssignEquation) as;
PointsToSetVariable rhs = assign.getRightHandSide();
int rhsRep = pointsToMap.getRepresentative(pointsToMap.getIndex(rhs.getPointerKey()));
if (rhsRep == rep) {
flowGraph.removeStatement(as);
} else {
replaceLHS(pRef, p, as);
}
} else {
replaceLHS(pRef, p, as);
}
}
// be careful: cache the defs before mucking with the underlying system
for (Iterator u = Iterator2Collection.toSet(getStatementsThatUse(p)).iterator(); u.hasNext();) {
AbstractStatement as = (AbstractStatement) u.next();
if (as instanceof AssignEquation) {
AssignEquation assign = (AssignEquation) as;
PointsToSetVariable lhs = assign.getLHS();
int lhsRep = pointsToMap.getRepresentative(pointsToMap.getIndex(lhs.getPointerKey()));
if (lhsRep == rep) {
flowGraph.removeStatement(as);
} else {
replaceRHS(pRef, p, as);
}
} else {
replaceRHS(pRef, p, as);
}
}
if (flowGraph.getNumberOfStatementsThatDef(p) == 0 && flowGraph.getNumberOfStatementsThatUse(p) == 0) {
flowGraph.removeVariable(p);
}
}
}
}
/**
* replace all occurrences of p on the rhs of a statement with pRef
*
* @param as a statement that uses p in it's right-hand side
*/
private void replaceRHS(PointsToSetVariable pRef, PointsToSetVariable p,
AbstractStatement<PointsToSetVariable, AbstractOperator<PointsToSetVariable>> as) {
if (as instanceof UnaryStatement) {
assert ((UnaryStatement) as).getRightHandSide() == p;
newStatement(as.getLHS(), (UnaryOperator<PointsToSetVariable>) as.getOperator(), pRef, false, false);
} else {
IVariable[] rhs = as.getRHS();
PointsToSetVariable[] newRHS = new PointsToSetVariable[rhs.length];
for (int i = 0; i < rhs.length; i++) {
if (rhs[i].equals(p)) {
newRHS[i] = pRef;
} else {
newRHS[i] = (PointsToSetVariable) rhs[i];
}
}
newStatement(as.getLHS(), as.getOperator(), newRHS, false, false);
}
flowGraph.removeStatement(as);
}
/**
* replace all occurences of p on the lhs of a statement with pRef
*
* @param as a statement that defs p
*/
private void replaceLHS(PointsToSetVariable pRef, PointsToSetVariable p,
AbstractStatement<PointsToSetVariable, AbstractOperator<PointsToSetVariable>> as) {
assert as.getLHS() == p;
if (as instanceof UnaryStatement) {
newStatement(pRef, (UnaryOperator<PointsToSetVariable>) as.getOperator(), (PointsToSetVariable) ((UnaryStatement) as)
.getRightHandSide(), false, false);
} else {
newStatement(pRef, as.getOperator(), as.getRHS(), false, false);
}
flowGraph.removeStatement(as);
}
public boolean isUnified(PointerKey result) {
return pointsToMap.isUnified(result);
}
public int getNumber(PointerKey p) {
return pointsToMap.getIndex(p);
}
@Override
protected PointsToSetVariable[] makeStmtRHS(int size) {
return new PointsToSetVariable[size];
}
}
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