path: root/libevmasm/AssemblyItem.h

/*
    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/>.
*/
/** @file AssemblyItem.h
 * @author Gav Wood <i@gavwood.com>
 * @date 2014
 */

#pragma once

#include <iostream>
#include <sstream>
#include <libdevcore/Common.h>
#include <libdevcore/Assertions.h>
#include <libevmasm/Instruction.h>
#include <libevmasm/SourceLocation.h>
#include "Exceptions.h"
using namespace dev::solidity;

namespace dev
{
namespace eth
{

enum AssemblyItemType {
    UndefinedItem,
    Operation,
    Push,
    PushString,
    PushTag,
    PushSub,
    PushSubSize,
    PushProgramSize,
    Tag,
    PushData,
    PushLibraryAddress, ///< Push a currently unknown address of another (library) contract.
    PushDeployTimeAddress ///< Push an address to be filled at deploy time. Should not be touched by the optimizer.
};

class Assembly;

class AssemblyItem
{
public:
    enum class JumpType { Ordinary, IntoFunction, OutOfFunction };

    AssemblyItem(u256 _push, SourceLocation const& _location = SourceLocation()):
        AssemblyItem(Push, _push, _location) { }
    AssemblyItem(solidity::Instruction _i, SourceLocation const& _location = SourceLocation()):
        m_type(Operation),
        m_instruction(_i),
        m_location(_location)
    {}
    AssemblyItem(AssemblyItemType _type, u256 _data = 0, SourceLocation const& _location = SourceLocation()):
        m_type(_type),
        m_location(_location)
    {
        if (m_type == Operation)
            m_instruction = Instruction(byte(_data));
        else
            m_data = std::make_shared<u256>(_data);
    }

    AssemblyItem tag() const { assertThrow(m_type == PushTag || m_type == Tag, Exception, ""); return AssemblyItem(Tag, data()); }
    AssemblyItem pushTag() const { assertThrow(m_type == PushTag || m_type == Tag, Exception, ""); return AssemblyItem(PushTag, data()); }
    /// Converts the tag to a subassembly tag. This has to be called in order to move a tag across assemblies.
    /// @param _subId the identifier of the subassembly the tag is taken from.
    AssemblyItem toSubAssemblyTag(size_t _subId) const;
    /// @returns splits the data of the push tag into sub assembly id and actual tag id.
    /// The sub assembly id of non-foreign push tags is -1.
    std::pair<size_t, size_t> splitForeignPushTag() const;
    /// Sets sub-assembly part and tag for a push tag.
    void setPushTagSubIdAndTag(size_t _subId, size_t _tag);

    AssemblyItemType type() const { return m_type; }
    u256 const& data() const { assertThrow(m_type != Operation, Exception, ""); return *m_data; }
    void setData(u256 const& _data) { assertThrow(m_type != Operation, Exception, ""); m_data = std::make_shared<u256>(_data); }

    /// @returns the instruction of this item (only valid if type() == Operation)
    Instruction instruction() const { assertThrow(m_type == Operation, Exception, ""); return m_instruction; }

    /// @returns true if the type and data of the items are equal.
    bool operator==(AssemblyItem const& _other) const
    {
        if (type() != _other.type())
            return false;
        if (type() == Operation)
            return instruction() == _other.instruction();
        else
            return data() == _other.data();
    }
    bool operator!=(AssemblyItem const& _other) const { return !operator==(_other); }
    /// Less-than operator compatible with operator==.
    bool operator<(AssemblyItem const& _other) const
    {
        if (type() != _other.type())
            return type() < _other.type();
        else if (type() == Operation)
            return instruction() < _other.instruction();
        else
            return data() < _other.data();
    }

    /// @returns an upper bound for the number of bytes required by this item, assuming that
    /// the value of a jump tag takes @a _addressLength bytes.
    unsigned bytesRequired(unsigned _addressLength) const;
    int arguments() const;
    int returnValues() const;
    int deposit() const { return returnValues() - arguments(); }

    /// @returns true if the assembly item can be used in a functional context.
    bool canBeFunctional() const;

    void setLocation(SourceLocation const& _location) { m_location = _location; }
    SourceLocation const& location() const { return m_location; }

    void setJumpType(JumpType _jumpType) { m_jumpType = _jumpType; }
    JumpType getJumpType() const { return m_jumpType; }
    std::string getJumpTypeAsString() const;

    void setPushedValue(u256 const& _value) const { m_pushedValue = std::make_shared<u256>(_value); }
    u256 const* pushedValue() const { return m_pushedValue.get(); }

    std::string toAssemblyText() const;

private:
    AssemblyItemType m_type;
    Instruction m_instruction; ///< Only valid if m_type == Operation
    std::shared_ptr<u256> m_data; ///< Only valid if m_type != Operation
    SourceLocation m_location;
    JumpType m_jumpType = JumpType::Ordinary;
    /// Pushed value for operations with data to be determined during assembly stage,
    /// e.g. PushSubSize, PushTag, PushSub, etc.
    mutable std::shared_ptr<u256> m_pushedValue;
};

using AssemblyItems = std::vector<AssemblyItem>;

inline size_t bytesRequired(AssemblyItems const& _items, size_t _addressLength)
{
    size_t size = 0;
    for (AssemblyItem const& item: _items)
        size += item.bytesRequired(_addressLength);
    return size;
}

std::ostream& operator<<(std::ostream& _out, AssemblyItem const& _item);
inline std::ostream& operator<<(std::ostream& _out, AssemblyItems const& _items)
{
    for (AssemblyItem const& item: _items)
        _out << item;
    return _out;
}

}
}