@Override
public void transferInstruction(InstructionHandle handle, BasicBlock basicBlock, LockSet fact)
throws DataflowAnalysisException {
Instruction ins = handle.getInstruction();
short opcode = ins.getOpcode();
if (opcode == Constants.MONITORENTER || opcode == Constants.MONITOREXIT) {
ValueNumberFrame frame = vnaDataflow.getFactAtLocation(new Location(handle, basicBlock));
modifyLock(frame, fact, opcode == Constants.MONITORENTER ? 1 : -1);
} else if (opcode == Constants.INVOKEVIRTUAL || opcode == Constants.INVOKEINTERFACE) {
InvokeInstruction inv = (InvokeInstruction) ins;
String name = inv.getMethodName(methodGen.getConstantPool());
String sig = inv.getSignature(methodGen.getConstantPool());
ValueNumberFrame frame = vnaDataflow.getFactAtLocation(new Location(handle, basicBlock));
if ("()V".equals(sig) && ("lock".equals(name) || "lockInterruptibly".equals(name))) {
modifyLock(frame, fact, 1);
} else if ("()V".equals(sig) && ("unlock".equals(name))) {
modifyLock(frame, fact, -1);
}
} else if ((ins instanceof ReturnInstruction) && isSynchronized && !isStatic) {
lockOp(fact, vna.getThisValue().getNumber(), -1);
}
}
/** Checks the specific method for consistency. */
public static void checkMgen(MethodGen mgen) {
if (skip_checks) return;
try {
mgen.toString();
mgen.getLineNumberTable(mgen.getConstantPool());
InstructionList ilist = mgen.getInstructionList();
if (ilist == null || ilist.getStart() == null) return;
CodeExceptionGen[] exceptionHandlers = mgen.getExceptionHandlers();
for (CodeExceptionGen gen : exceptionHandlers) {
assert ilist.contains(gen.getStartPC())
: "exception handler "
+ gen
+ " has been forgotten in "
+ mgen.getClassName()
+ "."
+ mgen.getName();
}
MethodGen nmg = new MethodGen(mgen.getMethod(), mgen.getClassName(), mgen.getConstantPool());
nmg.getLineNumberTable(mgen.getConstantPool());
} catch (Throwable t) {
System.out.printf("failure in method %s.%s\n", mgen.getClassName(), mgen.getName());
t.printStackTrace();
throw new Error(t);
}
}
/**
* 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);
}
}
}
/**
* Remove the local variable type table attribute (LVTT) from mg. Evidently some changes require
* this to be updated, but without BCEL support that would be hard to do. It should be safe to
* just delete it since it is optional and really only of use to a debugger.
*/
public static void remove_local_variable_type_tables(MethodGen mg) {
for (Attribute a : mg.getCodeAttributes()) {
if (is_local_variable_type_table(a, mg.getConstantPool())) {
mg.removeCodeAttribute(a);
}
}
}
/**
* 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);
}
}
/**
* Determine whether dataflow should be propagated on given edge.
*
* @param edge the edge
* @return true if dataflow should be propagated on the edge, false otherwise
*/
private boolean isExceptionEdge(Edge edge) {
boolean isExceptionEdge = edge.isExceptionEdge();
if (isExceptionEdge) {
if (DEBUG) {
System.out.println("NOT Ignoring " + edge);
}
return true; // false
}
if (edge.getType() != EdgeTypes.FALL_THROUGH_EDGE) {
return false;
}
InstructionHandle h = edge.getSource().getLastInstruction();
if (h != null
&& h.getInstruction() instanceof IFNONNULL
&& isNullCheck(h, methodGen.getConstantPool())) {
return true;
}
return false;
}
/**
* Return whether or not given instruction is an assertion.
*
* @param handle the instruction
* @return true if instruction is an assertion, false otherwise
*/
private boolean isAssertion(InstructionHandle handle) {
return assertionMethods.isAssertionHandle(handle, methodGen.getConstantPool());
}
/**
* 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);
}
@Override
public void transferInstruction(
InstructionHandle handle, BasicBlock basicBlock, UnconditionalValueDerefSet fact)
throws DataflowAnalysisException {
Instruction instruction = handle.getInstruction();
if (fact.isTop()) {
return;
}
Location location = new Location(handle, basicBlock);
// If this is a call to an assertion method,
// change the dataflow value to be TOP.
// We don't want to report future derefs that would
// be guaranteed only if the assertion methods
// returns normally.
// TODO: at some point, evaluate whether we should revisit this
if (isAssertion(handle) // || handle.getInstruction() instanceof ATHROW
) {
if (DEBUG) {
System.out.println("MAKING BOTTOM0 AT: " + location);
}
fact.clear();
return;
}
// Get value number frame
ValueNumberFrame vnaFrame = vnaDataflow.getFactAtLocation(location);
if (!vnaFrame.isValid()) {
if (DEBUG) {
System.out.println("MAKING TOP1 AT: " + location);
}
// Probably dead code.
// Assume this location can't be reached.
makeFactTop(fact);
return;
}
if (isNullCheck(handle, methodGen.getConstantPool())) {
handleNullCheck(location, vnaFrame, fact);
}
// Check for calls to a method that unconditionally dereferences
// a parameter. Mark any such arguments as derefs.
if (CHECK_CALLS && instruction instanceof InvokeInstruction) {
checkUnconditionalDerefDatabase(location, vnaFrame, fact);
}
// If this is a method call instruction,
// check to see if any of the parameters are @NonNull,
// and treat them as dereferences.
if (CHECK_ANNOTATIONS && instruction instanceof InvokeInstruction) {
checkNonNullParams(location, vnaFrame, fact);
}
if (CHECK_ANNOTATIONS && instruction instanceof ARETURN) {
XMethod thisMethod = XFactory.createXMethod(methodGen);
checkNonNullReturnValue(thisMethod, location, vnaFrame, fact);
}
if (CHECK_ANNOTATIONS
&& (instruction instanceof PUTFIELD || instruction instanceof PUTSTATIC)) {
checkNonNullPutField(location, vnaFrame, fact);
}
// Check to see if an instance value is dereferenced here
checkInstance(location, vnaFrame, fact);
/*
if (false) {
fact.cleanDerefSet(location, vnaFrame);
}*/
if (DEBUG && fact.isTop()) {
System.out.println("MAKING TOP2 At: " + location);
}
}
/** Constructor. */
MethodVisitor(MethodGen m, ClassVisitor c) {
mg = m;
cv = c;
cp = mg.getConstantPool();
cm = cv.getMetrics();
}
/**
* Whenever the outgoing frame situation of an InstructionContext changes, all its successors are
* put [back] into the queue [as if they were unvisited]. The proof of termination is about the
* existence of a fix point of frame merging.
*/
private void circulationPump(
MethodGen m,
ControlFlowGraph cfg,
InstructionContext start,
Frame vanillaFrame,
InstConstraintVisitor icv,
ExecutionVisitor ev) {
final Random random = new Random();
InstructionContextQueue icq = new InstructionContextQueue();
start.execute(
vanillaFrame,
new ArrayList<InstructionContext>(),
icv,
ev); // new ArrayList() <=> no Instruction was executed before
// => Top-Level routine (no jsr call before)
icq.add(start, new ArrayList<InstructionContext>());
// LOOP!
while (!icq.isEmpty()) {
InstructionContext u;
ArrayList<InstructionContext> ec;
if (!DEBUG) {
int r = random.nextInt(icq.size());
u = icq.getIC(r);
ec = icq.getEC(r);
icq.remove(r);
} else {
u = icq.getIC(0);
ec = icq.getEC(0);
icq.remove(0);
}
@SuppressWarnings("unchecked") // ec is of type ArrayList<InstructionContext>
ArrayList<InstructionContext> oldchain = (ArrayList<InstructionContext>) (ec.clone());
@SuppressWarnings("unchecked") // ec is of type ArrayList<InstructionContext>
ArrayList<InstructionContext> newchain = (ArrayList<InstructionContext>) (ec.clone());
newchain.add(u);
if ((u.getInstruction().getInstruction()) instanceof RET) {
// System.err.println(u);
// We can only follow _one_ successor, the one after the
// JSR that was recently executed.
RET ret = (RET) (u.getInstruction().getInstruction());
ReturnaddressType t =
(ReturnaddressType) u.getOutFrame(oldchain).getLocals().get(ret.getIndex());
InstructionContext theSuccessor = cfg.contextOf(t.getTarget());
// Sanity check
InstructionContext lastJSR = null;
int skip_jsr = 0;
for (int ss = oldchain.size() - 1; ss >= 0; ss--) {
if (skip_jsr < 0) {
throw new AssertionViolatedException("More RET than JSR in execution chain?!");
}
// System.err.println("+"+oldchain.get(ss));
if ((oldchain.get(ss)).getInstruction().getInstruction() instanceof JsrInstruction) {
if (skip_jsr == 0) {
lastJSR = oldchain.get(ss);
break;
}
skip_jsr--;
}
if ((oldchain.get(ss)).getInstruction().getInstruction() instanceof RET) {
skip_jsr++;
}
}
if (lastJSR == null) {
throw new AssertionViolatedException(
"RET without a JSR before in ExecutionChain?! EC: '" + oldchain + "'.");
}
JsrInstruction jsr = (JsrInstruction) (lastJSR.getInstruction().getInstruction());
if (theSuccessor != (cfg.contextOf(jsr.physicalSuccessor()))) {
throw new AssertionViolatedException(
"RET '"
+ u.getInstruction()
+ "' info inconsistent: jump back to '"
+ theSuccessor
+ "' or '"
+ cfg.contextOf(jsr.physicalSuccessor())
+ "'?");
}
if (theSuccessor.execute(u.getOutFrame(oldchain), newchain, icv, ev)) {
@SuppressWarnings(
"unchecked") // newchain is already of type ArrayList<InstructionContext>
ArrayList<InstructionContext> newchainClone =
(ArrayList<InstructionContext>) newchain.clone();
icq.add(theSuccessor, newchainClone);
}
} else { // "not a ret"
// Normal successors. Add them to the queue of successors.
InstructionContext[] succs = u.getSuccessors();
for (InstructionContext v : succs) {
if (v.execute(u.getOutFrame(oldchain), newchain, icv, ev)) {
@SuppressWarnings(
"unchecked") // newchain is already of type ArrayList<InstructionContext>
ArrayList<InstructionContext> newchainClone =
(ArrayList<InstructionContext>) newchain.clone();
icq.add(v, newchainClone);
}
}
} // end "not a ret"
// Exception Handlers. Add them to the queue of successors.
// [subroutines are never protected; mandated by JustIce]
ExceptionHandler[] exc_hds = u.getExceptionHandlers();
for (ExceptionHandler exc_hd : exc_hds) {
InstructionContext v = cfg.contextOf(exc_hd.getHandlerStart());
// TODO: the "oldchain" and "newchain" is used to determine the subroutine
// we're in (by searching for the last JSR) by the InstructionContext
// implementation. Therefore, we should not use this chain mechanism
// when dealing with exception handlers.
// Example: a JSR with an exception handler as its successor does not
// mean we're in a subroutine if we go to the exception handler.
// We should address this problem later; by now we simply "cut" the chain
// by using an empty chain for the exception handlers.
// if (v.execute(new Frame(u.getOutFrame(oldchain).getLocals(), new OperandStack
// (u.getOutFrame().getStack().maxStack(), (exc_hds[s].getExceptionType()==null?
// Type.THROWABLE : exc_hds[s].getExceptionType())) ), newchain), icv, ev){
// icq.add(v, (ArrayList) newchain.clone());
if (v.execute(
new Frame(
u.getOutFrame(oldchain).getLocals(),
new OperandStack(
u.getOutFrame(oldchain).getStack().maxStack(),
(exc_hd.getExceptionType() == null
? Type.THROWABLE
: exc_hd.getExceptionType()))),
new ArrayList<InstructionContext>(),
icv,
ev)) {
icq.add(v, new ArrayList<InstructionContext>());
}
}
} // while (!icq.isEmpty()) END
InstructionHandle ih = start.getInstruction();
do {
if ((ih.getInstruction() instanceof ReturnInstruction) && (!(cfg.isDead(ih)))) {
InstructionContext ic = cfg.contextOf(ih);
Frame f =
ic.getOutFrame(
new ArrayList<
InstructionContext>()); // TODO: This is buggy, we check only the top-level
// return instructions this way. Maybe some maniac
// returns from a method when in a subroutine?
LocalVariables lvs = f.getLocals();
for (int i = 0; i < lvs.maxLocals(); i++) {
if (lvs.get(i) instanceof UninitializedObjectType) {
this.addMessage(
"Warning: ReturnInstruction '"
+ ic
+ "' may leave method with an uninitialized object in the local variables array '"
+ lvs
+ "'.");
}
}
OperandStack os = f.getStack();
for (int i = 0; i < os.size(); i++) {
if (os.peek(i) instanceof UninitializedObjectType) {
this.addMessage(
"Warning: ReturnInstruction '"
+ ic
+ "' may leave method with an uninitialized object on the operand stack '"
+ os
+ "'.");
}
}
// see JVM $4.8.2
// TODO implement all based on stack
Type returnedType = null;
InstructionHandle ihPrev = null;
ihPrev = ih.getPrev();
if (ihPrev != null) {
if (ihPrev.getInstruction() instanceof InvokeInstruction) {
returnedType =
((InvokeInstruction) ihPrev.getInstruction()).getType(m.getConstantPool());
}
if (ihPrev.getInstruction() instanceof LoadInstruction) {
int index = ((LoadInstruction) ihPrev.getInstruction()).getIndex();
returnedType = lvs.get(index);
}
if (ihPrev.getInstruction() instanceof GETFIELD) {
returnedType = ((GETFIELD) ihPrev.getInstruction()).getType(m.getConstantPool());
}
}
if (returnedType != null) {
if (returnedType instanceof ObjectType) {
try {
if (!((ObjectType) returnedType).isAssignmentCompatibleWith(m.getReturnType())) {
throw new StructuralCodeConstraintException(
"Returned type "
+ returnedType
+ " does not match Method's return type "
+ m.getReturnType());
}
} catch (ClassNotFoundException e) {
// dont know what do do now, so raise RuntimeException
throw new RuntimeException(e);
}
} else if (!returnedType.equals(m.getReturnType())) {
throw new StructuralCodeConstraintException(
"Returned type "
+ returnedType
+ " does not match Method's return type "
+ m.getReturnType());
}
}
}
} while ((ih = ih.getNext()) != null);
}