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WALA/com.ibm.wala.core/src/com/ibm/wala/ipa/callgraph/propagation/PointerAnalysisImpl.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.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import com.ibm.wala.classLoader.IClass;
import com.ibm.wala.classLoader.IField;
import com.ibm.wala.classLoader.Language;
import com.ibm.wala.classLoader.NewSiteReference;
import com.ibm.wala.classLoader.ProgramCounter;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.ipa.callgraph.CallGraph;
import com.ibm.wala.ipa.cha.IClassHierarchy;
import com.ibm.wala.ssa.DefUse;
import com.ibm.wala.ssa.IR;
import com.ibm.wala.ssa.SSAAbstractInvokeInstruction;
import com.ibm.wala.ssa.SSAArrayLoadInstruction;
import com.ibm.wala.ssa.SSACheckCastInstruction;
import com.ibm.wala.ssa.SSAGetCaughtExceptionInstruction;
import com.ibm.wala.ssa.SSAGetInstruction;
import com.ibm.wala.ssa.SSAInstruction;
import com.ibm.wala.ssa.SSAInvokeInstruction;
import com.ibm.wala.ssa.SSANewInstruction;
import com.ibm.wala.ssa.SSAPhiInstruction;
import com.ibm.wala.ssa.SSAPiInstruction;
import com.ibm.wala.ssa.SSAThrowInstruction;
import com.ibm.wala.types.FieldReference;
import com.ibm.wala.types.TypeReference;
import com.ibm.wala.util.collections.HashSetFactory;
import com.ibm.wala.util.collections.Iterator2Iterable;
import com.ibm.wala.util.debug.Assertions;
import com.ibm.wala.util.intset.IntSet;
import com.ibm.wala.util.intset.MutableMapping;
import com.ibm.wala.util.intset.MutableSparseIntSet;
import com.ibm.wala.util.intset.OrdinalSet;
/**
* General representation of the results of pointer analysis
*/
public class PointerAnalysisImpl extends AbstractPointerAnalysis {
/**
* mapping from PointerKey to PointsToSetVariable
*/
private final PointsToMap pointsToMap;
/**
* Meta-data regarding heap abstractions
*/
private final HeapModel H;
/**
* An object that abstracts how to model pointers in the heap.
*/
protected final PointerKeyFactory pointerKeys;
/**
* An object that abstracts how to model instances in the heap.
*/
private final InstanceKeyFactory iKeyFactory;
protected final PropagationCallGraphBuilder builder;
public PointerAnalysisImpl(PropagationCallGraphBuilder builder, CallGraph cg, PointsToMap pointsToMap,
MutableMapping<InstanceKey> instanceKeys, PointerKeyFactory pointerKeys, InstanceKeyFactory iKeyFactory) {
super(cg, instanceKeys);
this.builder = builder;
this.pointerKeys = pointerKeys;
this.iKeyFactory = iKeyFactory;
this.pointsToMap = pointsToMap;
if (iKeyFactory == null) {
throw new IllegalArgumentException("null iKeyFactory");
}
H = makeHeapModel();
}
@Override
public String toString() {
StringBuffer result = new StringBuffer("PointerAnalysis:\n");
for (Iterator it = pointsToMap.iterateKeys(); it.hasNext();) {
PointerKey p = (PointerKey) it.next();
OrdinalSet O = getPointsToSet(p);
result.append(" ").append(p).append(" ->\n");
for (Iterator it2 = O.iterator(); it2.hasNext();) {
result.append(" ").append(it2.next()).append("\n");
}
}
return result.toString();
}
protected HeapModel makeHeapModel() {
return new HModel();
}
/*
* @see com.ibm.wala.ipa.callgraph.propagation.PointerAnalysis#getPointsToSet(com.ibm.wala.ipa.callgraph.propagation.PointerKey)
*/
@Override
@SuppressWarnings("unchecked")
public OrdinalSet<InstanceKey> getPointsToSet(PointerKey key) {
if (pointsToMap.isImplicit(key)) {
return computeImplicitPointsToSet(key);
}
// special logic to handle contents of char[] from string constants.
if (key instanceof InstanceFieldKey) {
InstanceFieldKey ifk = (InstanceFieldKey) key;
if (ifk.getInstanceKey() instanceof ConstantKey) {
ConstantKey<?> i = (ConstantKey<?>) ifk.getInstanceKey();
if (i.getValue() instanceof String && i.getConcreteType().getClassLoader().getLanguage().equals(Language.JAVA)) {
StringConstantCharArray contents = StringConstantCharArray.make((ConstantKey<String>) i);
instanceKeys.add(contents);
Collection<InstanceKey> singleton = HashSetFactory.make();
singleton.add(contents);
return OrdinalSet.toOrdinalSet(singleton, instanceKeys);
}
}
}
PointsToSetVariable v = pointsToMap.getPointsToSet(key);
if (v == null) {
return OrdinalSet.empty();
} else {
IntSet S = v.getValue();
return new OrdinalSet<InstanceKey>(S, instanceKeys);
}
}
/**
* did the pointer analysis use a type filter for a given points-to set? (this is ugly).
*/
@Override
public boolean isFiltered(PointerKey key) {
if (pointsToMap.isImplicit(key)) {
return false;
}
PointsToSetVariable v = pointsToMap.getPointsToSet(key);
if (v == null) {
return false;
} else {
return v.getPointerKey() instanceof FilteredPointerKey;
}
}
public static class ImplicitPointsToSetVisitor extends SSAInstruction.Visitor {
protected final PointerAnalysisImpl analysis;
protected final CGNode node;
protected final LocalPointerKey lpk;
protected OrdinalSet<InstanceKey> pointsToSet = null;
protected ImplicitPointsToSetVisitor(PointerAnalysisImpl analysis, LocalPointerKey lpk) {
this.lpk = lpk;
this.node = lpk.getNode();
this.analysis = analysis;
}
@Override
public void visitNew(SSANewInstruction instruction) {
pointsToSet = OrdinalSet.empty();
}
@Override
public void visitInvoke(SSAInvokeInstruction instruction) {
pointsToSet = analysis.computeImplicitPointsToSetAtCall(lpk, node, instruction);
}
@Override
public void visitCheckCast(SSACheckCastInstruction instruction) {
pointsToSet = analysis.computeImplicitPointsToSetAtCheckCast(node, instruction);
}
@Override
public void visitGetCaughtException(SSAGetCaughtExceptionInstruction instruction) {
pointsToSet = analysis.computeImplicitPointsToSetAtCatch(node, instruction);
}
@Override
public void visitGet(SSAGetInstruction instruction) {
pointsToSet = analysis.computeImplicitPointsToSetAtGet(node, instruction);
}
@Override
public void visitPhi(SSAPhiInstruction instruction) {
pointsToSet = analysis.computeImplicitPointsToSetAtPhi(node, instruction);
}
@Override
public void visitPi(SSAPiInstruction instruction) {
pointsToSet = analysis.computeImplicitPointsToSetAtPi(node, instruction);
}
@Override
public void visitArrayLoad(SSAArrayLoadInstruction instruction) {
pointsToSet = analysis.computeImplicitPointsToSetAtALoad(node, instruction);
}
}
protected ImplicitPointsToSetVisitor makeImplicitPointsToVisitor(LocalPointerKey lpk) {
return new ImplicitPointsToSetVisitor(this, lpk);
}
private OrdinalSet<InstanceKey> computeImplicitPointsToSet(PointerKey key) {
if (key instanceof LocalPointerKey) {
LocalPointerKey lpk = (LocalPointerKey) key;
CGNode node = lpk.getNode();
IR ir = node.getIR();
DefUse du = node.getDU();
if (((SSAPropagationCallGraphBuilder) builder).contentsAreInvariant(ir.getSymbolTable(), du, lpk.getValueNumber())) {
// cons up the points-to set for invariant contents
InstanceKey[] ik = ((SSAPropagationCallGraphBuilder) builder).getInvariantContents(ir.getSymbolTable(), du, node, lpk
.getValueNumber(), H, true);
return toOrdinalSet(ik);
} else {
SSAInstruction def = du.getDef(lpk.getValueNumber());
if (def != null) {
ImplicitPointsToSetVisitor v = makeImplicitPointsToVisitor(lpk);
def.visit(v);
if (v.pointsToSet != null) {
return v.pointsToSet;
} else {
Assertions.UNREACHABLE("saw " + key + ": time to implement for " + def.getClass());
return null;
}
} else {
Assertions.UNREACHABLE("unexpected null def for " + key);
return null;
}
}
} else {
Assertions.UNREACHABLE("unexpected implicit key " + key + " that's not a local pointer key");
return null;
}
}
private OrdinalSet<InstanceKey> computeImplicitPointsToSetAtPi(CGNode node, SSAPiInstruction instruction) {
MutableSparseIntSet S = MutableSparseIntSet.makeEmpty();
for (int i = 0; i < instruction.getNumberOfUses(); i++) {
int vn = instruction.getUse(i);
if (vn != -1) {
PointerKey lpk = pointerKeys.getPointerKeyForLocal(node, vn);
OrdinalSet pointees = getPointsToSet(lpk);
IntSet set = pointees.getBackingSet();
if (set != null) {
S.addAll(set);
}
}
}
return new OrdinalSet<InstanceKey>(S, instanceKeys);
}
private OrdinalSet<InstanceKey> computeImplicitPointsToSetAtPhi(CGNode node, SSAPhiInstruction instruction) {
MutableSparseIntSet S = MutableSparseIntSet.makeEmpty();
for (int i = 0; i < instruction.getNumberOfUses(); i++) {
int vn = instruction.getUse(i);
if (vn != -1) {
PointerKey lpk = pointerKeys.getPointerKeyForLocal(node, vn);
OrdinalSet pointees = getPointsToSet(lpk);
IntSet set = pointees.getBackingSet();
if (set != null) {
S.addAll(set);
}
}
}
return new OrdinalSet<InstanceKey>(S, instanceKeys);
}
private OrdinalSet<InstanceKey> computeImplicitPointsToSetAtALoad(CGNode node, SSAArrayLoadInstruction instruction) {
PointerKey arrayRef = pointerKeys.getPointerKeyForLocal(node, instruction.getArrayRef());
MutableSparseIntSet S = MutableSparseIntSet.makeEmpty();
OrdinalSet refs = getPointsToSet(arrayRef);
for (Iterator it = refs.iterator(); it.hasNext();) {
InstanceKey ik = (InstanceKey) it.next();
PointerKey key = pointerKeys.getPointerKeyForArrayContents(ik);
OrdinalSet pointees = getPointsToSet(key);
IntSet set = pointees.getBackingSet();
if (set != null) {
S.addAll(set);
}
}
return new OrdinalSet<InstanceKey>(S, instanceKeys);
}
private OrdinalSet<InstanceKey> computeImplicitPointsToSetAtGet(CGNode node, SSAGetInstruction instruction) {
return computeImplicitPointsToSetAtGet(node, instruction.getDeclaredField(), instruction.getRef(), instruction.isStatic());
}
public OrdinalSet<InstanceKey> computeImplicitPointsToSetAtGet(CGNode node, FieldReference field, int refVn, boolean isStatic) {
IField f = getCallGraph().getClassHierarchy().resolveField(field);
if (f == null) {
return OrdinalSet.empty();
}
if (isStatic) {
PointerKey fKey = pointerKeys.getPointerKeyForStaticField(f);
return getPointsToSet(fKey);
} else {
PointerKey ref = pointerKeys.getPointerKeyForLocal(node, refVn);
MutableSparseIntSet S = MutableSparseIntSet.makeEmpty();
OrdinalSet refs = getPointsToSet(ref);
for (Iterator it = refs.iterator(); it.hasNext();) {
InstanceKey ik = (InstanceKey) it.next();
PointerKey fkey = pointerKeys.getPointerKeyForInstanceField(ik, f);
if (fkey != null) {
OrdinalSet pointees = getPointsToSet(fkey);
IntSet set = pointees.getBackingSet();
if (set != null) {
S.addAll(set);
}
}
}
return new OrdinalSet<InstanceKey>(S, instanceKeys);
}
}
private OrdinalSet<InstanceKey> computeImplicitPointsToSetAtCatch(CGNode node, SSAGetCaughtExceptionInstruction instruction) {
IR ir = node.getIR();
List<ProgramCounter> peis = SSAPropagationCallGraphBuilder.getIncomingPEIs(ir, ir.getBasicBlockForCatch(instruction));
Set<IClass> caughtTypes = SSAPropagationCallGraphBuilder.getCaughtExceptionTypes(instruction, ir);
MutableSparseIntSet S = MutableSparseIntSet.makeEmpty();
// add the instances from each incoming pei ...
for (Iterator<ProgramCounter> it = peis.iterator(); it.hasNext();) {
ProgramCounter peiLoc = it.next();
SSAInstruction pei = ir.getPEI(peiLoc);
PointerKey e = null;
// first deal with exception variables from calls and throws.
if (pei instanceof SSAAbstractInvokeInstruction) {
SSAAbstractInvokeInstruction s = (SSAAbstractInvokeInstruction) pei;
e = pointerKeys.getPointerKeyForLocal(node, s.getException());
} else if (pei instanceof SSAThrowInstruction) {
SSAThrowInstruction s = (SSAThrowInstruction) pei;
e = pointerKeys.getPointerKeyForLocal(node, s.getException());
}
if (e != null) {
OrdinalSet ep = getPointsToSet(e);
for (Iterator it2 = ep.iterator(); it2.hasNext();) {
InstanceKey ik = (InstanceKey) it2.next();
if (PropagationCallGraphBuilder.catches(caughtTypes, ik.getConcreteType(), getCallGraph().getClassHierarchy())) {
S.add(instanceKeys.getMappedIndex(ik));
}
}
}
// Account for those exceptions for which we do not actually have a
// points-to set for
// the pei, but just instance keys
Collection types = pei.getExceptionTypes();
if (types != null) {
for (Iterator it2 = types.iterator(); it2.hasNext();) {
TypeReference type = (TypeReference) it2.next();
if (type != null) {
InstanceKey ik = SSAPropagationCallGraphBuilder.getInstanceKeyForPEI(node, peiLoc, type, iKeyFactory);
ConcreteTypeKey ck = (ConcreteTypeKey) ik;
IClass klass = ck.getType();
if (PropagationCallGraphBuilder.catches(caughtTypes, klass, getCallGraph().getClassHierarchy())) {
S.add(instanceKeys.getMappedIndex(SSAPropagationCallGraphBuilder
.getInstanceKeyForPEI(node, peiLoc, type, iKeyFactory)));
}
}
}
}
}
return new OrdinalSet<InstanceKey>(S, instanceKeys);
}
private OrdinalSet<InstanceKey> computeImplicitPointsToSetAtCheckCast(CGNode node, SSACheckCastInstruction instruction) {
PointerKey rhs = pointerKeys.getPointerKeyForLocal(node, instruction.getVal());
OrdinalSet<InstanceKey> rhsSet = getPointsToSet(rhs);
MutableSparseIntSet S = MutableSparseIntSet.makeEmpty();
for (TypeReference t : instruction.getDeclaredResultTypes()) {
IClass klass = getCallGraph().getClassHierarchy().lookupClass(t);
if (klass == null) {
// could not find the type. conservatively assume Object
return rhsSet;
} else {
if (klass.isInterface()) {
for (Iterator it = rhsSet.iterator(); it.hasNext();) {
InstanceKey ik = (InstanceKey) it.next();
if (getCallGraph().getClassHierarchy().implementsInterface(ik.getConcreteType(), klass)) {
S.add(getInstanceKeyMapping().getMappedIndex(ik));
}
}
} else {
for (Iterator it = rhsSet.iterator(); it.hasNext();) {
InstanceKey ik = (InstanceKey) it.next();
if (getCallGraph().getClassHierarchy().isSubclassOf(ik.getConcreteType(), klass)) {
S.add(getInstanceKeyMapping().getMappedIndex(ik));
}
}
}
}
}
return new OrdinalSet<InstanceKey>(S, instanceKeys);
}
private OrdinalSet<InstanceKey> computeImplicitPointsToSetAtCall(LocalPointerKey lpk, CGNode node, SSAInvokeInstruction call) {
int exc = call.getException();
if (lpk.getValueNumber() == exc) {
return computeImplicitExceptionsForCall(node, call);
} else {
Assertions.UNREACHABLE("time to implement me.");
return null;
}
}
private OrdinalSet<InstanceKey> toOrdinalSet(InstanceKey[] ik) {
MutableSparseIntSet s = MutableSparseIntSet.makeEmpty();
for (int i = 0; i < ik.length; i++) {
int index = instanceKeys.getMappedIndex(ik[i]);
if (index != -1) {
s.add(index);
} else {
assert index != -1 : "instance " + ik[i] + " not mapped!";
}
}
return new OrdinalSet<InstanceKey>(s, instanceKeys);
}
/**
* @return the points-to set for the exceptional return values from a particular call site
*/
private OrdinalSet<InstanceKey> computeImplicitExceptionsForCall(CGNode node, SSAInvokeInstruction call) {
MutableSparseIntSet S = MutableSparseIntSet.makeEmpty();
for (Iterator it = getCallGraph().getPossibleTargets(node, call.getCallSite()).iterator(); it.hasNext();) {
CGNode target = (CGNode) it.next();
PointerKey retVal = pointerKeys.getPointerKeyForExceptionalReturnValue(target);
IntSet set = getPointsToSet(retVal).getBackingSet();
if (set != null) {
S.addAll(set);
}
}
return new OrdinalSet<InstanceKey>(S, instanceKeys);
}
/*
* @see com.ibm.wala.ipa.callgraph.propagation.PointerAnalysis#getHeapModel()
*/
@Override
public HeapModel getHeapModel() {
return H;
}
protected class HModel implements HeapModel {
@Override
public Iterator<PointerKey> iteratePointerKeys() {
return pointsToMap.iterateKeys();
}
@Override
public InstanceKey getInstanceKeyForAllocation(CGNode node, NewSiteReference allocation) {
return iKeyFactory.getInstanceKeyForAllocation(node, allocation);
}
@Override
public InstanceKey getInstanceKeyForMultiNewArray(CGNode node, NewSiteReference allocation, int dim) {
return iKeyFactory.getInstanceKeyForMultiNewArray(node, allocation, dim);
}
@Override
public <T> InstanceKey getInstanceKeyForConstant(TypeReference type, T S) {
return iKeyFactory.getInstanceKeyForConstant(type, S);
}
@Override
public InstanceKey getInstanceKeyForPEI(CGNode node, ProgramCounter peiLoc, TypeReference type) {
return iKeyFactory.getInstanceKeyForPEI(node, peiLoc, type);
}
@Override
public InstanceKey getInstanceKeyForMetadataObject(Object obj, TypeReference objType) {
return iKeyFactory.getInstanceKeyForMetadataObject(obj, objType);
}
/*
* @see com.ibm.wala.ipa.callgraph.propagation.PointerKeyFactory#getPointerKeyForLocal(com.ibm.detox.ipa.callgraph.CGNode, int)
*/
@Override
public PointerKey getPointerKeyForLocal(CGNode node, int valueNumber) {
return pointerKeys.getPointerKeyForLocal(node, valueNumber);
}
@Override
public FilteredPointerKey getFilteredPointerKeyForLocal(CGNode node, int valueNumber, FilteredPointerKey.TypeFilter filter) {
return pointerKeys.getFilteredPointerKeyForLocal(node, valueNumber, filter);
}
/*
* @see com.ibm.wala.ipa.callgraph.propagation.PointerKeyFactory#getPointerKeyForReturnValue(com.ibm.detox.ipa.callgraph.CGNode)
*/
@Override
public PointerKey getPointerKeyForReturnValue(CGNode node) {
return pointerKeys.getPointerKeyForReturnValue(node);
}
/*
* @see
* com.ibm.wala.ipa.callgraph.propagation.PointerKeyFactory#getPointerKeyForExceptionalReturnValue(com.ibm.detox.ipa.callgraph
* .CGNode)
*/
@Override
public PointerKey getPointerKeyForExceptionalReturnValue(CGNode node) {
return pointerKeys.getPointerKeyForExceptionalReturnValue(node);
}
/*
* @see
* com.ibm.wala.ipa.callgraph.propagation.PointerKeyFactory#getPointerKeyForStaticField(com.ibm.wala.classLoader.FieldReference)
*/
@Override
public PointerKey getPointerKeyForStaticField(IField f) {
return pointerKeys.getPointerKeyForStaticField(f);
}
/*
* @see
* com.ibm.wala.ipa.callgraph.propagation.PointerKeyFactory#getPointerKeyForInstance(com.ibm.wala.ipa.callgraph.propagation.
* InstanceKey, com.ibm.wala.classLoader.FieldReference)
*/
@Override
public PointerKey getPointerKeyForInstanceField(InstanceKey I, IField field) {
assert field != null;
return pointerKeys.getPointerKeyForInstanceField(I, field);
}
/*
* @see
* com.ibm.wala.ipa.callgraph.propagation.PointerKeyFactory#getPointerKeyForArrayContents(com.ibm.wala.ipa.callgraph.propagation
* .InstanceKey)
*/
@Override
public PointerKey getPointerKeyForArrayContents(InstanceKey I) {
return pointerKeys.getPointerKeyForArrayContents(I);
}
@Override
public IClassHierarchy getClassHierarchy() {
return getCallGraph().getClassHierarchy();
}
}
/*
* @see com.ibm.wala.ipa.callgraph.propagation.PointerAnalysis#iteratePointerKeys()
*/
@Override
public Iterable<PointerKey> getPointerKeys() {
return Iterator2Iterable.make(pointsToMap.iterateKeys());
}
@Override
public IClassHierarchy getClassHierarchy() {
return builder.getClassHierarchy();
}
}
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