public static Set<ValueNumber> checkAllNonNullParams(
Location location,
ValueNumberFrame vnaFrame,
ConstantPoolGen constantPool,
@CheckForNull Method method,
@CheckForNull IsNullValueDataflow invDataflow,
TypeDataflow typeDataflow)
throws DataflowAnalysisException {
IsNullValueFrame invFrame = null;
if (invDataflow != null) {
invFrame = invDataflow.getFactAtLocation(location);
}
Set<ValueNumber> result1 =
checkNonNullParams(location, vnaFrame, constantPool, method, invFrame);
Set<ValueNumber> result2 =
checkUnconditionalDerefDatabase(location, vnaFrame, constantPool, invFrame, typeDataflow);
if (result1.isEmpty()) {
return result2;
}
if (result2.isEmpty()) {
return result1;
}
result1.addAll(result2);
return result1;
}
/**
* If this is a putfield or putstatic instruction, check to see if the field is @NonNull, and
* treat it as dereferences.
*
* @param location the Location of the instruction
* @param vnaFrame the ValueNumberFrame at the Location of the instruction
* @param fact the dataflow value to modify
* @throws DataflowAnalysisException
*/
private void checkNonNullPutField(
Location location, ValueNumberFrame vnaFrame, UnconditionalValueDerefSet fact)
throws DataflowAnalysisException {
INullnessAnnotationDatabase database =
AnalysisContext.currentAnalysisContext().getNullnessAnnotationDatabase();
FieldInstruction fieldIns = (FieldInstruction) location.getHandle().getInstruction();
XField field = XFactory.createXField(fieldIns, methodGen.getConstantPool());
char firstChar = field.getSignature().charAt(0);
if (firstChar != 'L' && firstChar != '[') {
return;
}
NullnessAnnotation resolvedAnnotation = database.getResolvedAnnotation(field, true);
if (resolvedAnnotation == NullnessAnnotation.NONNULL) {
IsNullValueFrame invFrame = invDataflow.getFactAtLocation(location);
if (!invFrame.isValid()) {
return;
}
IsNullValue value = invFrame.getTopValue();
if (reportDereference(value)) {
ValueNumber vn = vnaFrame.getTopValue();
fact.addDeref(vn, location);
}
}
}
private void handleNullCheck(
Location location, ValueNumberFrame vnaFrame, UnconditionalValueDerefSet fact)
throws DataflowAnalysisException {
if (reportPotentialDereference(location, invDataflow.getFactAtLocation(location))) {
ValueNumber vn = vnaFrame.getTopValue();
fact.addDeref(vn, location);
}
}
/**
* If this is a method call instruction, check to see if any of the parameters are @NonNull, and
* treat them as dereferences.
*
* @param location the Location of the instruction
* @param vnaFrame the ValueNumberFrame at the Location of the instruction
* @param fact the dataflow value to modify
* @throws DataflowAnalysisException
*/
private void checkNonNullParams(
Location location, ValueNumberFrame vnaFrame, UnconditionalValueDerefSet fact)
throws DataflowAnalysisException {
ConstantPoolGen constantPool = methodGen.getConstantPool();
Set<ValueNumber> nonNullParams =
checkNonNullParams(
location, vnaFrame, constantPool, method, invDataflow.getFactAtLocation(location));
for (ValueNumber vn : nonNullParams) {
fact.addDeref(vn, location);
}
}
/**
* Check method call at given location to see if it unconditionally dereferences a parameter. Mark
* any such arguments as derefs.
*
* @param location the Location of the method call
* @param vnaFrame ValueNumberFrame at the Location
* @param fact the dataflow value to modify
* @throws DataflowAnalysisException
*/
private void checkUnconditionalDerefDatabase(
Location location, ValueNumberFrame vnaFrame, UnconditionalValueDerefSet fact)
throws DataflowAnalysisException {
ConstantPoolGen constantPool = methodGen.getConstantPool();
for (ValueNumber vn :
checkUnconditionalDerefDatabase(
location,
vnaFrame,
constantPool,
invDataflow.getFactAtLocation(location),
typeDataflow)) {
fact.addDeref(vn, location);
}
}
/**
* If this is a method call instruction, check to see if any of the parameters are @NonNull, and
* treat them as dereferences.
*
* @param location the Location of the instruction
* @param vnaFrame the ValueNumberFrame at the Location of the instruction
* @param fact the dataflow value to modify
* @throws DataflowAnalysisException
*/
private void checkNonNullReturnValue(
XMethod thisMethod,
Location location,
ValueNumberFrame vnaFrame,
UnconditionalValueDerefSet fact)
throws DataflowAnalysisException {
INullnessAnnotationDatabase database =
AnalysisContext.currentAnalysisContext().getNullnessAnnotationDatabase();
if (database.getResolvedAnnotation(thisMethod, true) != NullnessAnnotation.NONNULL) {
return;
}
if (reportPotentialDereference(location, invDataflow.getFactAtLocation(location))) {
ValueNumber vn = vnaFrame.getTopValue();
fact.addDeref(vn, location);
}
}
/**
* Clear deref sets of values if this edge is the non-null branch of an if comparison.
*
* @param fact a datflow fact
* @param edge edge to check
* @return possibly-modified dataflow fact
*/
private @CheckForNull ValueNumber findValueKnownNonnullOnBranch(
UnconditionalValueDerefSet fact, Edge edge) {
IsNullValueFrame invFrame = invDataflow.getResultFact(edge.getSource());
if (!invFrame.isValid()) {
return null;
}
IsNullConditionDecision decision = invFrame.getDecision();
if (decision == null) {
return null;
}
IsNullValue inv = decision.getDecision(edge.getType());
if (inv == null || !inv.isDefinitelyNotNull()) {
return null;
}
ValueNumber value = decision.getValue();
if (DEBUG) {
System.out.println("Value number " + value + " is known nonnull on " + edge);
}
return value;
}
/**
* Check to see if the instruction has a null check associated with it, and if so, add a
* dereference.
*
* @param location the Location of the instruction
* @param vnaFrame ValueNumberFrame at the Location of the instruction
* @param fact the dataflow value to modify
* @throws DataflowAnalysisException
*/
private void checkInstance(
Location location, ValueNumberFrame vnaFrame, UnconditionalValueDerefSet fact)
throws DataflowAnalysisException {
// See if this instruction has a null check.
// If it does, the fall through predecessor will be
// identify itself as the null check.
if (!location.isFirstInstructionInBasicBlock()) {
return;
}
if (invDataflow == null) {
return;
}
BasicBlock fallThroughPredecessor =
cfg.getPredecessorWithEdgeType(location.getBasicBlock(), EdgeTypes.FALL_THROUGH_EDGE);
if (fallThroughPredecessor == null || !fallThroughPredecessor.isNullCheck()) {
return;
}
// Get the null-checked value
ValueNumber vn =
vnaFrame.getInstance(location.getHandle().getInstruction(), methodGen.getConstantPool());
// Ignore dereferences of this
if (!methodGen.isStatic()) {
ValueNumber v = vnaFrame.getValue(0);
if (v.equals(vn)) {
return;
}
}
if (vn.hasFlag(ValueNumber.CONSTANT_CLASS_OBJECT)) {
return;
}
IsNullValueFrame startFact = null;
startFact = invDataflow.getStartFact(fallThroughPredecessor);
if (!startFact.isValid()) {
return;
}
int slot =
startFact.getInstanceSlot(
location.getHandle().getInstruction(), methodGen.getConstantPool());
if (!reportDereference(startFact, slot)) {
return;
}
if (DEBUG) {
System.out.println("FOUND GUARANTEED DEREFERENCE");
System.out.println("Load: " + vnaFrame.getLoad(vn));
System.out.println("Pred: " + fallThroughPredecessor);
System.out.println("startFact: " + startFact);
System.out.println("Location: " + location);
System.out.println("Value number frame: " + vnaFrame);
System.out.println("Dereferenced valueNumber: " + vn);
System.out.println("invDataflow: " + startFact);
System.out.println("IGNORE_DEREF_OF_NCP: " + IGNORE_DEREF_OF_NCP);
}
// Mark the value number as being dereferenced at this location
fact.addDeref(vn, location);
}
