path: root/libjulia/backends/evm/AbstractAssembly.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/>.
*/
/**
 * @date 2017
 * Abstract assembly interface, subclasses of which are to be used with the generic
 * bytecode generator.
 */

#pragma once

#include <libdevcore/CommonData.h>

#include <functional>

namespace dev
{
struct SourceLocation;
namespace solidity
{
enum class Instruction: uint8_t;
namespace assembly
{
struct Instruction;
struct Identifier;
}
}
namespace julia
{

class AbstractAssembly
{
public:
    virtual ~AbstractAssembly() {}

    /// Set a new source location valid starting from the next instruction.
    virtual void setSourceLocation(SourceLocation const& _location) = 0;
    /// Retrieve the current height of the stack. This does not have to be zero
    /// at the beginning.
    virtual int stackHeight() const = 0;
    /// Append an EVM instruction.
    virtual void appendInstruction(solidity::Instruction _instruction) = 0;
    /// Append a constant.
    virtual void appendConstant(u256 const& _constant) = 0;
    /// Append a label.
    virtual void appendLabel(size_t _labelId) = 0;
    /// Append a label reference.
    virtual void appendLabelReference(size_t _labelId) = 0;
    /// Generate a new unique label.
    virtual size_t newLabelId() = 0;
    /// Append a reference to a to-be-linked symobl.
    /// Currently, we assume that the value is always a 20 byte number.
    virtual void appendLinkerSymbol(std::string const& _name) = 0;
};

enum class IdentifierContext { LValue, RValue };

/// Object that is used to resolve references and generate code for access to identifiers external
/// to inline assembly (not used in standalone assembly mode).
struct ExternalIdentifierAccess
{
    using Resolver = std::function<size_t(solidity::assembly::Identifier const&, IdentifierContext)>;
    /// Resolve a an external reference given by the identifier in the given context.
    /// @returns the size of the value (number of stack slots) or size_t(-1) if not found.
    Resolver resolve;
    using CodeGenerator = std::function<void(solidity::assembly::Identifier const&, IdentifierContext, julia::AbstractAssembly&)>;
    /// Generate code for retrieving the value (rvalue context) or storing the value (lvalue context)
    /// of an identifier. The code should be appended to the assembly. In rvalue context, the value is supposed
    /// to be put onto the stack, in lvalue context, the value is assumed to be at the top of the stack.
    CodeGenerator generateCode;
};



}
}