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Merge pull request #9854 from ethereum/bitwiseSmt

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[SMTChecker] Support compound shifts and bitwise and, or, and xor
This commit is contained in:
Đorđe Mijović
2020-09-23 12:35:48 +02:00
committed by GitHub
parent c1bb1eb070 96bafb9ba3
commit 858b4507e2
26 changed files with 363 additions and 135 deletions
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libsolidity/formal/SMTEncoder.cpp
+83 -60
View File
@@ -352,31 +352,10 @@ void SMTEncoder::endVisit(Assignment const& _assignment)
{
createExpr(_assignment);
static set<Token> const compoundOps{
Token::AssignAdd,
Token::AssignSub,
Token::AssignMul,
Token::AssignDiv,
Token::AssignMod
};
Token op = _assignment.assignmentOperator();
if (op != Token::Assign && !compoundOps.count(op))
{
Expression const* identifier = &_assignment.leftHandSide();
if (auto const* indexAccess = dynamic_cast<IndexAccess const*>(identifier))
identifier = leftmostBase(*indexAccess);
// Give it a new index anyway to keep the SSA scheme sound.
solAssert(identifier, "");
if (auto varDecl = identifierToVariable(*identifier))
m_context.newValue(*varDecl);
solAssert(TokenTraits::isAssignmentOp(op), "");
m_errorReporter.warning(
9149_error,
_assignment.location(),
"Assertion checker does not yet implement this assignment operator."
);
}
else if (!smt::isSupportedType(*_assignment.annotation().type))
if (!smt::isSupportedType(*_assignment.annotation().type))
{
// Give it a new index anyway to keep the SSA scheme sound.
@@ -394,9 +373,9 @@ void SMTEncoder::endVisit(Assignment const& _assignment)
else
{
auto const& type = _assignment.annotation().type;
auto rightHandSide = compoundOps.count(op) ?
compoundAssignment(_assignment) :
expr(_assignment.rightHandSide(), type);
auto rightHandSide = op == Token::Assign ?
expr(_assignment.rightHandSide(), type) :
compoundAssignment(_assignment);
defineExpr(_assignment, rightHandSide);
assignment(
_assignment.leftHandSide(),
@@ -1388,6 +1367,59 @@ pair<smtutil::Expression, smtutil::Expression> SMTEncoder::arithmeticOperation(
return {value, valueUnbounded};
}
smtutil::Expression SMTEncoder::bitwiseOperation(
Token _op,
smtutil::Expression const& _left,
smtutil::Expression const& _right,
TypePointer const& _commonType
)
{
static set<Token> validOperators{
Token::BitAnd,
Token::BitOr,
Token::BitXor,
Token::SHL,
Token::SHR,
Token::SAR
};
solAssert(validOperators.count(_op), "");
solAssert(_commonType, "");
auto [bvSize, isSigned] = smt::typeBvSizeAndSignedness(_commonType);
auto bvLeft = smtutil::Expression::int2bv(_left, bvSize);
auto bvRight = smtutil::Expression::int2bv(_right, bvSize);
optional<smtutil::Expression> result;
switch (_op)
{
case Token::BitAnd:
result = bvLeft & bvRight;
break;
case Token::BitOr:
result = bvLeft | bvRight;
break;
case Token::BitXor:
result = bvLeft ^ bvRight;
break;
case Token::SHL:
result = bvLeft << bvRight;
break;
case Token::SHR:
solAssert(false, "");
case Token::SAR:
result = isSigned ?
smtutil::Expression::ashr(bvLeft, bvRight) :
bvLeft >> bvRight;
break;
default:
solAssert(false, "");
}
solAssert(result.has_value(), "");
return smtutil::Expression::bv2int(*result, isSigned);
}
void SMTEncoder::compareOperation(BinaryOperation const& _op)
{
auto const& commonType = _op.annotation().commonType;
@@ -1464,39 +1496,12 @@ void SMTEncoder::bitwiseOperation(BinaryOperation const& _op)
auto commonType = _op.annotation().commonType;
solAssert(commonType, "");
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);
optional<smtutil::Expression> result;
switch (op)
{
case Token::BitAnd:
result = bvLeft & bvRight;
break;
case Token::BitOr:
result = bvLeft | bvRight;
break;
case Token::BitXor:
result = bvLeft ^ bvRight;
break;
case Token::SHL:
result = bvLeft << bvRight;
break;
case Token::SHR:
solAssert(false, "");
case Token::SAR:
result = isSigned ?
smtutil::Expression::ashr(bvLeft, bvRight) :
bvLeft >> bvRight;
break;
default:
solAssert(false, "");
}
solAssert(result, "");
defineExpr(_op, smtutil::Expression::bv2int(*result, isSigned));
defineExpr(_op, bitwiseOperation(
_op.getOperator(),
expr(_op.leftExpression(), commonType),
expr(_op.rightExpression(), commonType),
commonType
));
}
void SMTEncoder::bitwiseNotOperation(UnaryOperation const& _op)
@@ -1604,9 +1609,27 @@ smtutil::Expression SMTEncoder::compoundAssignment(Assignment const& _assignment
{Token::AssignDiv, Token::Div},
{Token::AssignMod, Token::Mod}
};
static map<Token, Token> const compoundToBitwise{
{Token::AssignBitAnd, Token::BitAnd},
{Token::AssignBitOr, Token::BitOr},
{Token::AssignBitXor, Token::BitXor},
{Token::AssignShl, Token::SHL},
{Token::AssignShr, Token::SHR},
{Token::AssignSar, Token::SAR}
};
Token op = _assignment.assignmentOperator();
solAssert(compoundToArithmetic.count(op), "");
solAssert(compoundToArithmetic.count(op) || compoundToBitwise.count(op), "");
auto decl = identifierToVariable(_assignment.leftHandSide());
if (compoundToBitwise.count(op))
return bitwiseOperation(
compoundToBitwise.at(op),
decl ? currentValue(*decl) : expr(_assignment.leftHandSide()),
expr(_assignment.rightHandSide()),
_assignment.annotation().type
);
auto values = arithmeticOperation(
compoundToArithmetic.at(op),
decl ? currentValue(*decl) : expr(_assignment.leftHandSide()),
libsolidity/formal/SMTEncoder.h
+8
View File
@@ -119,6 +119,14 @@ protected:
TypePointer const& _commonType,
Expression const& _expression
);
smtutil::Expression bitwiseOperation(
Token _op,
smtutil::Expression const& _left,
smtutil::Expression const& _right,
TypePointer const& _commonType
);
void compareOperation(BinaryOperation const& _op);
void booleanOperation(BinaryOperation const& _op);
void bitwiseOperation(BinaryOperation const& _op);