ProgramStateRef SimpleConstraintManager::assumeSymRel(ProgramStateRef State,
const SymExpr *LHS,
BinaryOperator::Opcode Op,
const llvm::APSInt &Int) {
assert(BinaryOperator::isComparisonOp(Op) &&
"Non-comparison ops should be rewritten as comparisons to zero.");
// Get the type used for calculating wraparound.
BasicValueFactory &BVF = getBasicVals();
APSIntType WraparoundType = BVF.getAPSIntType(LHS->getType());
// We only handle simple comparisons of the form "$sym == constant"
// or "($sym+constant1) == constant2".
// The adjustment is "constant1" in the above expression. It's used to
// "slide" the solution range around for modular arithmetic. For example,
// x < 4 has the solution [0, 3]. x+2 < 4 has the solution [0-2, 3-2], which
// in modular arithmetic is [0, 1] U [UINT_MAX-1, UINT_MAX]. It's up to
// the subclasses of SimpleConstraintManager to handle the adjustment.
SymbolRef Sym = LHS;
llvm::APSInt Adjustment = WraparoundType.getZeroValue();
computeAdjustment(Sym, Adjustment);
// Convert the right-hand side integer as necessary.
APSIntType ComparisonType = std::max(WraparoundType, APSIntType(Int));
llvm::APSInt ConvertedInt = ComparisonType.convert(Int);
// Prefer unsigned comparisons.
if (ComparisonType.getBitWidth() == WraparoundType.getBitWidth() &&
ComparisonType.isUnsigned() && !WraparoundType.isUnsigned())
Adjustment.setIsSigned(false);
switch (Op) {
default:
llvm_unreachable("invalid operation not caught by assertion above");
case BO_EQ:
return assumeSymEQ(State, Sym, ConvertedInt, Adjustment);
case BO_NE:
return assumeSymNE(State, Sym, ConvertedInt, Adjustment);
case BO_GT:
return assumeSymGT(State, Sym, ConvertedInt, Adjustment);
case BO_GE:
return assumeSymGE(State, Sym, ConvertedInt, Adjustment);
case BO_LT:
return assumeSymLT(State, Sym, ConvertedInt, Adjustment);
case BO_LE:
return assumeSymLE(State, Sym, ConvertedInt, Adjustment);
} // end switch
}
ProgramStateRef SimpleConstraintManager::assumeSymRel(ProgramStateRef state,
const SymExpr *LHS,
BinaryOperator::Opcode op,
const llvm::APSInt& Int) {
assert(BinaryOperator::isComparisonOp(op) &&
"Non-comparison ops should be rewritten as comparisons to zero.");
BasicValueFactory &BVF = getBasicVals();
ASTContext &Ctx = BVF.getContext();
// Get the type used for calculating wraparound.
APSIntType WraparoundType = BVF.getAPSIntType(LHS->getType(Ctx));
// We only handle simple comparisons of the form "$sym == constant"
// or "($sym+constant1) == constant2".
// The adjustment is "constant1" in the above expression. It's used to
// "slide" the solution range around for modular arithmetic. For example,
// x < 4 has the solution [0, 3]. x+2 < 4 has the solution [0-2, 3-2], which
// in modular arithmetic is [0, 1] U [UINT_MAX-1, UINT_MAX]. It's up to
// the subclasses of SimpleConstraintManager to handle the adjustment.
SymbolRef Sym = LHS;
llvm::APSInt Adjustment = WraparoundType.getZeroValue();
computeAdjustment(Sym, Adjustment);
// Convert the right-hand side integer as necessary.
APSIntType ComparisonType = std::max(WraparoundType, APSIntType(Int));
llvm::APSInt ConvertedInt = ComparisonType.convert(Int);
switch (op) {
default:
// No logic yet for other operators. assume the constraint is feasible.
return state;
case BO_EQ:
return assumeSymEQ(state, Sym, ConvertedInt, Adjustment);
case BO_NE:
return assumeSymNE(state, Sym, ConvertedInt, Adjustment);
case BO_GT:
return assumeSymGT(state, Sym, ConvertedInt, Adjustment);
case BO_GE:
return assumeSymGE(state, Sym, ConvertedInt, Adjustment);
case BO_LT:
return assumeSymLT(state, Sym, ConvertedInt, Adjustment);
case BO_LE:
return assumeSymLE(state, Sym, ConvertedInt, Adjustment);
} // end switch
}
const ProgramState *SimpleConstraintManager::assumeSymRel(const ProgramState *state,
const SymExpr *LHS,
BinaryOperator::Opcode op,
const llvm::APSInt& Int) {
assert(BinaryOperator::isComparisonOp(op) &&
"Non-comparison ops should be rewritten as comparisons to zero.");
// We only handle simple comparisons of the form "$sym == constant"
// or "($sym+constant1) == constant2".
// The adjustment is "constant1" in the above expression. It's used to
// "slide" the solution range around for modular arithmetic. For example,
// x < 4 has the solution [0, 3]. x+2 < 4 has the solution [0-2, 3-2], which
// in modular arithmetic is [0, 1] U [UINT_MAX-1, UINT_MAX]. It's up to
// the subclasses of SimpleConstraintManager to handle the adjustment.
llvm::APSInt Adjustment;
// First check if the LHS is a simple symbol reference.
SymbolRef Sym = dyn_cast<SymbolData>(LHS);
if (Sym) {
Adjustment = 0;
} else {
// Next, see if it's a "($sym+constant1)" expression.
const SymIntExpr *SE = dyn_cast<SymIntExpr>(LHS);
// We don't handle "($sym1+$sym2)".
// Give up and assume the constraint is feasible.
if (!SE)
return state;
// We don't handle "(<expr>+constant1)".
// Give up and assume the constraint is feasible.
Sym = dyn_cast<SymbolData>(SE->getLHS());
if (!Sym)
return state;
// Get the constant out of the expression "($sym+constant1)".
switch (SE->getOpcode()) {
case BO_Add:
Adjustment = SE->getRHS();
break;
case BO_Sub:
Adjustment = -SE->getRHS();
break;
default:
// We don't handle non-additive operators.
// Give up and assume the constraint is feasible.
return state;
}
}
// FIXME: This next section is a hack. It silently converts the integers to
// be of the same type as the symbol, which is not always correct. Really the
// comparisons should be performed using the Int's type, then mapped back to
// the symbol's range of values.
ProgramStateManager &StateMgr = state->getStateManager();
ASTContext &Ctx = StateMgr.getContext();
QualType T = Sym->getType(Ctx);
assert(T->isIntegerType() || Loc::isLocType(T));
unsigned bitwidth = Ctx.getTypeSize(T);
bool isSymUnsigned
= T->isUnsignedIntegerOrEnumerationType() || Loc::isLocType(T);
// Convert the adjustment.
Adjustment.setIsUnsigned(isSymUnsigned);
Adjustment = Adjustment.extOrTrunc(bitwidth);
// Convert the right-hand side integer.
llvm::APSInt ConvertedInt(Int, isSymUnsigned);
ConvertedInt = ConvertedInt.extOrTrunc(bitwidth);
switch (op) {
default:
// No logic yet for other operators. assume the constraint is feasible.
return state;
case BO_EQ:
return assumeSymEQ(state, Sym, ConvertedInt, Adjustment);
case BO_NE:
return assumeSymNE(state, Sym, ConvertedInt, Adjustment);
case BO_GT:
return assumeSymGT(state, Sym, ConvertedInt, Adjustment);
case BO_GE:
return assumeSymGE(state, Sym, ConvertedInt, Adjustment);
case BO_LT:
return assumeSymLT(state, Sym, ConvertedInt, Adjustment);
case BO_LE:
return assumeSymLE(state, Sym, ConvertedInt, Adjustment);
} // end switch
}
