path: root/libyul/backends/evm/EVMAssembly.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/>.
*/
/**
 * Assembly interface for EVM and EVM1.5.
 */

#pragma once

#include <libyul/backends/evm/AbstractAssembly.h>

#include <libevmasm/LinkerObject.h>

#include <map>

namespace langutil
{
struct SourceLocation;
}

namespace yul
{

class EVMAssembly: public AbstractAssembly
{
public:
    explicit EVMAssembly(bool _evm15 = false): m_evm15(_evm15) { }
    virtual ~EVMAssembly() = default;

    /// Set a new source location valid starting from the next instruction.
    void setSourceLocation(langutil::SourceLocation const& _location) override;
    /// Retrieve the current height of the stack. This does not have to be zero
    /// at the beginning.
    int stackHeight() const override { return m_stackHeight; }
    /// Append an EVM instruction.
    void appendInstruction(dev::solidity::Instruction _instruction) override;
    /// Append a constant.
    void appendConstant(dev::u256 const& _constant) override;
    /// Append a label.
    void appendLabel(LabelID _labelId) override;
    /// Append a label reference.
    void appendLabelReference(LabelID _labelId) override;
    /// Generate a new unique label.
    LabelID newLabelId() override;
    /// Returns a label identified by the given name. Creates it if it does not yet exist.
    LabelID namedLabel(std::string const& _name) override;
    /// Append a reference to a to-be-linked symbol.
    /// Currently, we assume that the value is always a 20 byte number.
    void appendLinkerSymbol(std::string const& _name) override;

    /// Append a jump instruction.
    /// @param _stackDiffAfter the stack adjustment after this instruction.
    void appendJump(int _stackDiffAfter) override;
    /// Append a jump-to-immediate operation.
    void appendJumpTo(LabelID _labelId, int _stackDiffAfter) override;
    /// Append a jump-to-if-immediate operation.
    void appendJumpToIf(LabelID _labelId) override;
    /// Start a subroutine.
    void appendBeginsub(LabelID _labelId, int _arguments) override;
    /// Call a subroutine.
    void appendJumpsub(LabelID _labelId, int _arguments, int _returns) override;
    /// Return from a subroutine.
    void appendReturnsub(int _returns, int _stackDiffAfter) override;

    /// Append the assembled size as a constant.
    void appendAssemblySize() override;
    std::pair<std::shared_ptr<AbstractAssembly>, SubID> createSubAssembly() override;
    void appendDataOffset(SubID _sub) override;
    void appendDataSize(SubID _sub) override;
    SubID appendData(dev::bytes const& _data) override;

    /// Resolves references inside the bytecode and returns the linker object.
    dev::eth::LinkerObject finalize();

private:
    void setLabelToCurrentPosition(AbstractAssembly::LabelID _labelId);
    void appendLabelReferenceInternal(AbstractAssembly::LabelID _labelId);
    void updateReference(size_t pos, size_t size, dev::u256 value);

    bool m_evm15 = false; ///< if true, switch to evm1.5 mode
    LabelID m_nextLabelId = 0;
    int m_stackHeight = 0;
    dev::bytes m_bytecode;
    std::map<std::string, LabelID> m_namedLabels;
    std::map<LabelID, size_t> m_labelPositions;
    std::map<size_t, LabelID> m_labelReferences;
    std::vector<size_t> m_assemblySizePositions;
};

}