aboutsummaryrefslogtreecommitdiffstats
path: root/libsolidity/formal/SSAVariable.h
blob: 275e85900a1f2acbcde2d2ec5c7a9da6c9808da7 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
/*
    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/SymbolicVariable.h>

#include <memory>

namespace dev
{
namespace solidity
{

class Declaration;

/**
 * This class represents the SSA representation of a program variable.
 */
class SSAVariable
{
public:
    /// @param _decl Used to determine the type and forwarded to the symbolic var.
    /// @param _interface Forwarded to the symbolic var such that it can give constraints to the solver.
    SSAVariable(
        Declaration const* _decl,
        smt::SolverInterface& _interface
    );

    void resetIndex();

    /// This function returns the current index of this SSA variable.
    int index() const;
    /// This function returns the next free index of this SSA variable.
    int next() const;

    int operator++()
    {
        return m_currentSequenceCounter = (*m_nextFreeSequenceCounter)++;
    }

    smt::Expression operator()() const
    {
        return valueAtSequence(index());
    }

    smt::Expression operator()(int _seq) const
    {
        return valueAtSequence(_seq);
    }

    /// These two functions forward the call to the symbolic var
    /// which generates the constraints according to the type.
    void setZeroValue();
    void setUnknownValue();

    /// So far Int is supported.
    static bool supportedType(Type const* _decl);

private:
    smt::Expression valueAtSequence(int _seq) const
    {
        return (*m_symbolicVar)(_seq);
    }

    std::shared_ptr<SymbolicVariable> m_symbolicVar = nullptr;
    int m_currentSequenceCounter;
    /// The next free sequence counter is a shared pointer because we want
    /// the copy and the copied to share it.
    std::shared_ptr<int> m_nextFreeSequenceCounter;
};

}
}