Java Code Examples for soot.jimple.NullConstant#v()

@Override
protected void internalTransform(Body b, String phaseName, Map<String, String> options) {
	LocalCreation lc = new LocalCreation(b.getLocals(), "ex");
	
	for (Iterator<Unit> unitIt = b.getUnits().snapshotIterator(); unitIt.hasNext(); ) {
		Unit u = unitIt.next();
		
		// Check for a null exception
		if (u instanceof ThrowStmt) {
			ThrowStmt throwStmt = (ThrowStmt) u;
			if (throwStmt.getOp() == NullConstant.v()
					|| throwStmt.getOp().equals(IntConstant.v(0))
					|| throwStmt.getOp().equals(LongConstant.v(0))) {
				createThrowStmt(b, throwStmt, lc);
			}
		}
	}
}
 

private void handleEqualityOrNonEqualityCheck(AbstractBinopExpr eqExpr, AnalysisInfo in,
		AnalysisInfo out, AnalysisInfo outBranch) {
	Value left = eqExpr.getOp1();
	Value right = eqExpr.getOp2();
	
	Value val=null;
	if(left==NullConstant.v()) {
		if(right!=NullConstant.v()) {
			val = right;
		}
	} else if(right==NullConstant.v()) {
		if(left!=NullConstant.v()) {
			val = left;
		}
	}
	
	//if we compare a local with null then process further...
	if(val!=null && val instanceof Local) {
		if(eqExpr instanceof JEqExpr)
			//a==null
			handleEquality(val, out, outBranch);
		else if(eqExpr instanceof JNeExpr)
			//a!=null
			handleNonEquality(val, out, outBranch);
		else
			throw new IllegalStateException("unexpected condition: "+eqExpr.getClass());
	}
}
 

private void handleRefTypeAssignment(DefinitionStmt assignStmt, AnalysisInfo out) {
	Value left = assignStmt.getLeftOp();
	Value right = assignStmt.getRightOp();
	
	//unbox casted value
	if(right instanceof JCastExpr) {
		JCastExpr castExpr = (JCastExpr) right;
		right = castExpr.getOp();
	}
	
	//if we have a definition (assignment) statement to a ref-like type, handle it,
	if ( isAlwaysNonNull(right)
	|| right instanceof NewExpr || right instanceof NewArrayExpr
	|| right instanceof NewMultiArrayExpr || right instanceof ThisRef
	|| right instanceof StringConstant || right instanceof ClassConstant
	|| right instanceof CaughtExceptionRef) {
		//if we assign new... or @this, the result is non-null
		out.put(left,NON_NULL);
	} else if(right==NullConstant.v()) {
		//if we assign null, well, it's null
		out.put(left, NULL);
	} else if(left instanceof Local && right instanceof Local) {
		out.put(left, out.get(right));
	} else {
		out.put(left, TOP);
	}
}
 

/**
 * Checks whether the given local is guaranteed to be always null at the
 * given statement
 * @param s The statement at which to check the local
 * @param base The local to check
 * @param defs The definition analysis object to use for the check
 * @return True if the given local is guaranteed to always be null at the
 * given statement, otherwise false
 */
private boolean isAlwaysNullBefore(Stmt s, Local base, LocalDefs defs) {
	List<Unit> baseDefs = defs.getDefsOfAt(base, s);
	if (baseDefs.isEmpty())
		return true;
	
	for (Unit u : baseDefs) {
		if (!(u instanceof DefinitionStmt))
			return false;
		DefinitionStmt defStmt = (DefinitionStmt) u;
		if (defStmt.getRightOp() != NullConstant.v())
			return false;
	}
	return true;
}
 

private void convertConstInsn(InsnNode insn) {
	int op = insn.getOpcode();
	StackFrame frame = getFrame(insn);
	Operand[] out = frame.out();
	Operand opr;
	if (out == null) {
		Value v;
		if (op == ACONST_NULL)
			v = NullConstant.v();
		else if (op >= ICONST_M1 && op <= ICONST_5)
			v = IntConstant.v(op - ICONST_0);
		else if (op == LCONST_0 || op == LCONST_1)
			v = LongConstant.v(op - LCONST_0);
		else if (op >= FCONST_0 && op <= FCONST_2)
			v = FloatConstant.v(op - FCONST_0);
		else if (op == DCONST_0 || op == DCONST_1)
			v = DoubleConstant.v(op - DCONST_0);
		else
			throw new AssertionError("Unknown constant opcode: " + op);
		opr = new Operand(insn, v);
		frame.out(opr);
	} else {
		opr = out[0];
	}
	if (op == LCONST_0 || op == LCONST_1 ||
			op == DCONST_0 || op == DCONST_1) {
		pushDual(opr);
	} else {
		push(opr);
	}
}
 

public static Value toDefaultSootTypeValue(Type sootType)
{
	String type = sootType.toString();
	
	if ("boolean".equals(type))
	{
		IntConstant.v(0);
	}
	else if ("byte".equals(type))
	{
		return IntConstant.v(0);
	}
	else if ("char".equals(type))
	{
		return IntConstant.v(0);
	}
	else if ("short".equals(type))
	{
		return IntConstant.v(0);
	}
	else if ("int".equals(type))
	{
		return IntConstant.v(0);
	}
	else if ("long".equals(type))
	{
		return LongConstant.v(0);
	}
	else if ("float".equals(type))
	{
		return FloatConstant.v(0);
	}
	else if ("double".equals(type))
	{
		return DoubleConstant.v(0);
	}

	return NullConstant.v();
}