/**
* Translates a guard in an axiom to a prover expression
*
* @param exp
* @return
*/
private ProverExpr guardExpression2ProverExpr(Expression exp) {
if (exp instanceof BinOpExpression) {
/*
* TODO: this case should only occur for inlined axioms. The current
* type system is a bit messed up as it does not really allow
* boolean types in the Boogie program. If we do a major revision,
* we should definitely take care of this
*/
return expression2ProverExpr(exp);
} else if (exp instanceof IteExpression) {
return expression2ProverExpr(exp);
} else {
return theoremProver.mkEq(expression2ProverExpr(exp), theoremProver.mkLiteral(1));
}
}
/**
* generates a prover expression from an expression e
*
* @param e
* @param boundvars
* @return
*/
private ProverExpr expression2ProverExpr(Expression e, HashMap<Variable, ProverExpr> boundvars) {
try {
if (e instanceof ArrayReadExpression) {
ArrayReadExpression exp = (ArrayReadExpression) e;
return arrayExpression2ProverExpr(
exp.getBaseExpression(),
new LinkedList<Expression>(Arrays.asList(new Expression[] {exp.getIndexExpression()})),
null,
boundvars);
} else if (e instanceof InvokeExpression) {
InvokeExpression exp = (InvokeExpression) e;
ProverFun fun = procedure2ProverExpr(exp.getInvokedProcedure());
LinkedList<ProverExpr> args = new LinkedList<ProverExpr>();
for (Expression e2 : exp.getArguments()) {
args.add(expression2ProverExpr(e2, boundvars));
}
return fun.mkExpr((ProverExpr[]) args.toArray(new ProverExpr[args.size()]));
} else if (e instanceof SimpleHeapAccess) {
SimpleHeapAccess exp = (SimpleHeapAccess) e;
return arrayExpression2ProverExpr(
exp.getHeapVariable(),
new LinkedList<Expression>(
Arrays.asList(
new Expression[] {exp.getBaseExpression(), exp.getFieldExpression()})),
null,
boundvars);
} else if (e instanceof TypeExpression) {
TypeExpression exp = (TypeExpression) e;
return expression2ProverExpr(exp.getTypeVariable(), boundvars);
} else if (e instanceof Variable) {
Variable exp = (Variable) e;
if (boundvars.containsKey(exp)) {
return boundvars.get(exp);
}
if (!usedVariable.containsKey(exp)) {
ProverExpr pe =
theoremProver.mkVariable(
getProverFriendlyName(exp.getName()), type2ProverSort(exp.getType()));
usedVariable.put(exp, pe);
}
return usedVariable.get(exp);
} else if (e instanceof UboundedIntConstant) {
UboundedIntConstant exp = (UboundedIntConstant) e;
return theoremProver.mkLiteral(BigInteger.valueOf(exp.getValue()));
} else if (e instanceof Constant) {
Log.error("DEBUG-ERROR, there should not be any constant but Integers! VC will be wrong!");
return expression2ProverExpr(BoogieProgram.v().getNullReference(), boundvars);
} else if (e instanceof QuantifiedExpression) {
// TODO: right now, Quantifiers can only be used in Axioms
QuantifiedExpression qe = (QuantifiedExpression) e;
HashMap<Variable, ProverExpr> bvars = new HashMap<Variable, ProverExpr>(boundvars);
// LinkedList<ProverExpr> localBound = new
// LinkedList<ProverExpr>();
int idx = 0;
for (Variable v : qe.getBoundVariables()) {
ProverExpr boundvar = theoremProver.mkBoundVariable(idx++, type2ProverSort(v.getType()));
bvars.put(v, boundvar);
// localBound.add(boundvar);
}
ProverExpr boundExp = expression2ProverExpr(qe.getExpression(), bvars);
if (qe.getQuantifier() == Quantifier.ForAll) {
return theoremProver.mkAll(boundExp, theoremProver.getBooleanType());
} else {
return theoremProver.mkEx(boundExp, theoremProver.getBooleanType());
}
} else if (e instanceof BinOpExpression) {
BinOpExpression be = (BinOpExpression) e;
ProverExpr left = (expression2ProverExpr(be.getLhs(), boundvars));
ProverExpr right = (expression2ProverExpr(be.getRhs(), boundvars));
switch (be.getOp()) {
case Eq:
{
return theoremProver.mkEq(left, right);
}
case Lt:
{
return theoremProver.mkLt(left, right);
}
case Le:
{
return theoremProver.mkLeq(left, right);
}
case Gt:
{
return theoremProver.mkGt(left, right);
}
case Ge:
{
return theoremProver.mkGeq(left, right);
}
case Neq:
{
return theoremProver.mkNot(theoremProver.mkEq(left, right));
}
case Implies:
{
return theoremProver.mkOr(theoremProver.mkNot(left), right);
}
case LAnd:
{
return theoremProver.mkAnd(left, right);
}
case LOr:
{
return theoremProver.mkOr(left, right);
}
case Plus:
{
return theoremProver.mkPlus(left, right);
}
case Minus:
{
return theoremProver.mkMinus(left, right);
}
case Mul:
{
return theoremProver.mkMult(left, right);
}
default:
{
throw new RuntimeException("Unmatched binop: " + be.getOp().toString());
// TODO: a proper exception might be nice.
// However, this case can only occur if we screw up the
// implementation
}
}
} else if (e instanceof IteExpression) {
IteExpression ite = (IteExpression) e;
ProverExpr condE = expression2ProverExpr(ite.getCond(), boundvars);
ProverExpr thenE = expression2ProverExpr(ite.getThen(), boundvars);
ProverExpr elseE = expression2ProverExpr(ite.getElse(), boundvars);
return theoremProver.mkIte(condE, thenE, elseE);
} else {
Log.error("Unmatched Expression " + e.toString());
return null;
}
} catch (Exception exc) {
Log.error("expression2ProverExpr failed: " + exc.toString());
Log.error("Called on expression: " + e.toString());
if (e instanceof BinOpExpression) {
BinOpExpression boe = (BinOpExpression) e;
Log.error(boe.getLhs().getType().toString() + " and " + boe.getRhs().getType());
}
return null;
}
}