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/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <libsolidity/formal/SSAVariable.h>
#include <libsolidity/formal/SolverInterface.h>
#include <libsolidity/ast/Types.h>
#include <memory>
namespace dev
{
namespace solidity
{
class Type;
/**
* This abstract class represents the symbolic version of a program variable.
*/
class SymbolicVariable
{
public:
SymbolicVariable(
TypePointer _type,
std::string const& _uniqueName,
smt::SolverInterface& _interface
);
virtual ~SymbolicVariable() = default;
smt::Expression currentValue() const
{
return valueAtIndex(m_ssa->index());
}
std::string currentName() const;
virtual smt::Expression valueAtIndex(int _index) const = 0;
smt::Expression increaseIndex()
{
++(*m_ssa);
return currentValue();
}
unsigned index() const { return m_ssa->index(); }
unsigned& index() { return m_ssa->index(); }
/// Sets the var to the default value of its type.
/// Inherited types must implement.
virtual void setZeroValue() = 0;
/// The unknown value is the full range of valid values.
/// It is sub-type dependent, but not mandatory.
virtual void setUnknownValue() {}
protected:
std::string uniqueSymbol(unsigned _index) const;
TypePointer m_type = nullptr;
std::string m_uniqueName;
smt::SolverInterface& m_interface;
std::shared_ptr<SSAVariable> m_ssa = nullptr;
};
/**
* Specialization of SymbolicVariable for Bool
*/
class SymbolicBoolVariable: public SymbolicVariable
{
public:
SymbolicBoolVariable(
TypePointer _type,
std::string const& _uniqueName,
smt::SolverInterface& _interface
);
/// Sets the var to false.
void setZeroValue();
/// Does nothing since the SMT solver already knows the valid values for Bool.
void setUnknownValue();
protected:
smt::Expression valueAtIndex(int _index) const;
};
/**
* Specialization of SymbolicVariable for Integers
*/
class SymbolicIntVariable: public SymbolicVariable
{
public:
SymbolicIntVariable(
TypePointer _type,
std::string const& _uniqueName,
smt::SolverInterface& _interface
);
/// Sets the var to 0.
void setZeroValue();
/// Sets the variable to the full valid value range.
void setUnknownValue();
protected:
smt::Expression valueAtIndex(int _index) const;
};
/**
* Specialization of SymbolicVariable for Address
*/
class SymbolicAddressVariable: public SymbolicIntVariable
{
public:
SymbolicAddressVariable(
std::string const& _uniqueName,
smt::SolverInterface& _interface
);
};
/**
* Specialization of SymbolicVariable for FixedBytes
*/
class SymbolicFixedBytesVariable: public SymbolicIntVariable
{
public:
SymbolicFixedBytesVariable(
unsigned _numBytes,
std::string const& _uniqueName,
smt::SolverInterface& _interface
);
};
}
}
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