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Refactor computing symbolic arithmetic operation

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This commit is contained in:
Leonardo Alt 2019-03-28 12:42:32 +01:00
parent 2005e70fb9
commit ecbf36f271
2 changed files with 73 additions and 47 deletions
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108
libsolidity/formal/SMTChecker.cpp
View File

@ -1011,54 +1011,13 @@ void SMTChecker::arithmeticOperation(BinaryOperation const& _op)
case Token::Mul:
case Token::Div:
{
solAssert(_op.annotation().commonType, "");
if (_op.annotation().commonType->category() != Type::Category::Integer)
{
m_errorReporter.warning(
_op.location(),
"Assertion checker does not yet implement this operator on non-integer types."
);
break;
}
auto const& intType = dynamic_cast<IntegerType const&>(*_op.annotation().commonType);
smt::Expression left(expr(_op.leftExpression()));
smt::Expression right(expr(_op.rightExpression()));
Token op = _op.getOperator();
smt::Expression value(
op == Token::Add ? left + right :
op == Token::Sub ? left - right :
op == Token::Div ? division(left, right, intType) :
/*op == Token::Mul*/ left * right
);
if (_op.getOperator() == Token::Div)
{
checkCondition(right == 0, _op.location(), "Division by zero", "<result>", &right);
m_interface->addAssertion(right != 0);
}
addOverflowTarget(
OverflowTarget::Type::All,
defineExpr(_op, arithmeticOperation(
_op.getOperator(),
expr(_op.leftExpression()),
expr(_op.rightExpression()),
_op.annotation().commonType,
value,
_op.location()
);
smt::Expression intValueRange = (0 - minValue(intType)) + maxValue(intType) + 1;
defineExpr(_op, smt::Expression::ite(
value > maxValue(intType) || value < minValue(intType),
value % intValueRange,
value
));
if (intType.isSigned())
{
defineExpr(_op, smt::Expression::ite(
expr(_op) > maxValue(intType),
expr(_op) - intValueRange,
expr(_op)
));
}
break;
}
default:
@ -1069,6 +1028,63 @@ void SMTChecker::arithmeticOperation(BinaryOperation const& _op)
}
}
smt::Expression SMTChecker::arithmeticOperation(
Token _op,
smt::Expression const& _left,
smt::Expression const& _right,
TypePointer const& _commonType,
langutil::SourceLocation const& _location
)
{
static set<Token> validOperators{
Token::Add,
Token::Sub,
Token::Mul,
Token::Div
};
solAssert(validOperators.count(_op), "");
solAssert(_commonType, "");
solAssert(_commonType->category() == Type::Category::Integer, "");
auto const& intType = dynamic_cast<IntegerType const&>(*_commonType);
smt::Expression value(
_op == Token::Add ? _left + _right :
_op == Token::Sub ? _left - _right :
_op == Token::Div ? division(_left, _right, intType) :
/*op == Token::Mul*/ _left * _right
);
if (_op == Token::Div)
{
checkCondition(_right == 0, _location, "Division by zero", "<result>", &_right);
m_interface->addAssertion(_right != 0);
}
addOverflowTarget(
OverflowTarget::Type::All,
_commonType,
value,
_location
);
smt::Expression intValueRange = (0 - minValue(intType)) + maxValue(intType) + 1;
value = smt::Expression::ite(
value > maxValue(intType) || value < minValue(intType),
value % intValueRange,
value
);
if (intType.isSigned())
{
value = smt::Expression::ite(
value > maxValue(intType),
value - intValueRange,
value
);
}
return value;
}
void SMTChecker::compareOperation(BinaryOperation const& _op)
{
solAssert(_op.annotation().commonType, "");
@ -1179,7 +1195,7 @@ void SMTChecker::checkCondition(
SourceLocation const& _location,
string const& _description,
string const& _additionalValueName,
smt::Expression* _additionalValue
smt::Expression const* _additionalValue
)
{
m_interface->push();

12
libsolidity/formal/SMTChecker.h
View File

@ -88,6 +88,16 @@ private:
/// Symbolic _expr is the rational literal.
bool shortcutRationalNumber(Expression const& _expr);
void arithmeticOperation(BinaryOperation const& _op);
/// @returns _op(_left, _right).
/// Used by the function above, compound assignments and
/// unary increment/decrement.
smt::Expression arithmeticOperation(
Token _op,
smt::Expression const& _left,
smt::Expression const& _right,
TypePointer const& _commonType,
langutil::SourceLocation const& _location
);
void compareOperation(BinaryOperation const& _op);
void booleanOperation(BinaryOperation const& _op);
@ -137,7 +147,7 @@ private:
langutil::SourceLocation const& _location,
std::string const& _description,
std::string const& _additionalValueName = "",
smt::Expression* _additionalValue = nullptr
smt::Expression const* _additionalValue = nullptr
);
/// Checks that a boolean condition is not constant. Do not warn if the expression
/// is a literal constant.