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[SMTChecker] Support bitwise or, xor and not.

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This commit is contained in:
Djordje Mijovic
2020-08-26 11:06:56 +02:00
parent bff0f9bda7
commit 11a7763f49
18 changed files with 203 additions and 22 deletions
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libsolidity/formal/SMTEncoder.cpp
+18 -21
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@@ -456,6 +456,8 @@ void SMTEncoder::endVisit(TupleExpression const& _tuple)
void SMTEncoder::endVisit(UnaryOperation const& _op)
{
if (TokenTraits::isBitOp(_op.getOperator()))
return bitwiseNotOperation(_op);
if (_op.annotation().type->category() == Type::Category::RationalNumber)
return;
@@ -1406,20 +1408,7 @@ void SMTEncoder::bitwiseOperation(BinaryOperation const& _op)
auto commonType = _op.annotation().commonType;
solAssert(commonType, "");
unsigned bvSize = 256;
bool isSigned = false;
if (auto const* intType = dynamic_cast<IntegerType const*>(commonType))
{
bvSize = intType->numBits();
isSigned = intType->isSigned();
}
else if (auto const* fixedType = dynamic_cast<FixedPointType const*>(commonType))
{
bvSize = fixedType->numBits();
isSigned = fixedType->isSigned();
}
else if (auto const* fixedBytesType = dynamic_cast<FixedBytesType const*>(commonType))
bvSize = fixedBytesType->numBytes() * 8;
auto [bvSize, isSigned] = smt::typeBvSizeAndSignedness(commonType);
auto bvLeft = smtutil::Expression::int2bv(expr(_op.leftExpression(), commonType), bvSize);
auto bvRight = smtutil::Expression::int2bv(expr(_op.rightExpression(), commonType), bvSize);
@@ -1427,18 +1416,26 @@ void SMTEncoder::bitwiseOperation(BinaryOperation const& _op)
optional<smtutil::Expression> result;
if (_op.getOperator() == Token::BitAnd)
result = bvLeft & bvRight;
// TODO implement the other operators
else
m_errorReporter.warning(
1093_error,
_op.location(),
"Assertion checker does not yet implement this bitwise operator."
);
else if (_op.getOperator() == Token::BitOr)
result = bvLeft | bvRight;
else if (_op.getOperator() == Token::BitXor)
result = bvLeft ^ bvRight;
solAssert(result, "");
if (result)
defineExpr(_op, smtutil::Expression::bv2int(*result, isSigned));
}
void SMTEncoder::bitwiseNotOperation(UnaryOperation const& _op)
{
solAssert(_op.getOperator() == Token::BitNot, "");
auto [bvSize, isSigned] = smt::typeBvSizeAndSignedness(_op.annotation().type);
auto bvOperand = smtutil::Expression::int2bv(expr(_op.subExpression(), _op.annotation().type), bvSize);
defineExpr(_op, smtutil::Expression::bv2int(~bvOperand, isSigned));
}
smtutil::Expression SMTEncoder::division(smtutil::Expression _left, smtutil::Expression _right, IntegerType const& _type)
{
// Signed division in SMTLIB2 rounds differently for negative division.
libsolidity/formal/SMTEncoder.h
+1
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@@ -115,6 +115,7 @@ protected:
void compareOperation(BinaryOperation const& _op);
void booleanOperation(BinaryOperation const& _op);
void bitwiseOperation(BinaryOperation const& _op);
void bitwiseNotOperation(UnaryOperation const& _op);
void initContract(ContractDefinition const& _contract);
void initFunction(FunctionDefinition const& _function);
libsolidity/formal/SymbolicTypes.cpp
+12
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@@ -432,6 +432,18 @@ smtutil::Expression zeroValue(frontend::TypePointer const& _type)
return 0;
}
pair<unsigned, bool> typeBvSizeAndSignedness(frontend::TypePointer const& _type)
{
if (auto const* intType = dynamic_cast<IntegerType const*>(_type))
return {intType->numBits(), intType->isSigned()};
else if (auto const* fixedType = dynamic_cast<FixedPointType const*>(_type))
return {fixedType->numBits(), fixedType->isSigned()};
else if (auto const* fixedBytesType = dynamic_cast<FixedBytesType const*>(_type))
return {fixedBytesType->numBytes() * 8, false};
else
solAssert(false, "");
}
void setSymbolicUnknownValue(SymbolicVariable const& _variable, EncodingContext& _context)
{
setSymbolicUnknownValue(_variable.currentValue(), _variable.type(), _context);
libsolidity/formal/SymbolicTypes.h
+2
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@@ -67,6 +67,8 @@ smtutil::Expression minValue(frontend::IntegerType const& _type);
smtutil::Expression maxValue(frontend::IntegerType const& _type);
smtutil::Expression zeroValue(frontend::TypePointer const& _type);
std::pair<unsigned, bool> typeBvSizeAndSignedness(frontend::TypePointer const& type);
void setSymbolicZeroValue(SymbolicVariable const& _variable, EncodingContext& _context);
void setSymbolicZeroValue(smtutil::Expression _expr, frontend::TypePointer const& _type, EncodingContext& _context);
void setSymbolicUnknownValue(SymbolicVariable const& _variable, EncodingContext& _context);