path: root/CompilerContext.h

/*
    This file is part of cpp-ethereum.

    cpp-ethereum 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.

    cpp-ethereum 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 cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
/**
 * @author Christian <c@ethdev.com>
 * @date 2014
 * Utilities for the solidity compiler.
 */

#pragma once

#include <ostream>
#include <libevmcore/Instruction.h>
#include <libevmcore/Assembly.h>
#include <libsolidity/ASTForward.h>
#include <libsolidity/Types.h>

namespace dev {
namespace solidity {


/**
 * Context to be shared by all units that compile the same contract.
 * It stores the generated bytecode and the position of identifiers in memory and on the stack.
 */
class CompilerContext
{
public:
    void addMagicGlobal(MagicVariableDeclaration const& _declaration);
    void addStateVariable(VariableDeclaration const& _declaration);
    void startNewFunction() { m_localVariables.clear(); m_asm.setDeposit(0); }
    void addVariable(VariableDeclaration const& _declaration);
    void addAndInitializeVariable(VariableDeclaration const& _declaration);
    void addFunction(FunctionDefinition const& _function);

    void setCompiledContracts(std::map<ContractDefinition const*, bytes const*> const& _contracts) { m_compiledContracts = _contracts; }
    bytes const& getCompiledContract(ContractDefinition const& _contract) const;

    void adjustStackOffset(int _adjustment) { m_asm.adjustDeposit(_adjustment); }

    bool isMagicGlobal(Declaration const* _declaration) const { return m_magicGlobals.count(_declaration) != 0; }
    bool isFunctionDefinition(Declaration const* _declaration) const { return m_functionEntryLabels.count(_declaration) != 0; }
    bool isLocalVariable(Declaration const* _declaration) const;
    bool isStateVariable(Declaration const* _declaration) const { return m_stateVariables.count(_declaration) != 0; }

    eth::AssemblyItem getFunctionEntryLabel(FunctionDefinition const& _function) const;
    /// Returns the distance of the given local variable from the top of the local variable stack.
    unsigned getBaseStackOffsetOfVariable(Declaration const& _declaration) const;
    /// If supplied by a value returned by @ref getBaseStackOffsetOfVariable(variable), returns
    /// the distance of that variable from the current top of the stack.
    unsigned baseToCurrentStackOffset(unsigned _baseOffset) const;
    u256 getStorageLocationOfVariable(Declaration const& _declaration) const;

    /// Appends a JUMPI instruction to a new tag and @returns the tag
    eth::AssemblyItem appendConditionalJump() { return m_asm.appendJumpI().tag(); }
    /// Appends a JUMPI instruction to @a _tag
    CompilerContext& appendConditionalJumpTo(eth::AssemblyItem const& _tag) { m_asm.appendJumpI(_tag); return *this; }
    /// Appends a JUMP to a new tag and @returns the tag
    eth::AssemblyItem appendJumpToNew() { return m_asm.appendJump().tag(); }
    /// Appends a JUMP to a tag already on the stack
    CompilerContext&  appendJump() { return *this << eth::Instruction::JUMP; }
    /// Appends a JUMP to a specific tag
    CompilerContext& appendJumpTo(eth::AssemblyItem const& _tag) { m_asm.appendJump(_tag); return *this; }
    /// Appends pushing of a new tag and @returns the new tag.
    eth::AssemblyItem pushNewTag() { return m_asm.append(m_asm.newPushTag()).tag(); }
    /// @returns a new tag without pushing any opcodes or data
    eth::AssemblyItem newTag() { return m_asm.newTag(); }
    /// Adds a subroutine to the code (in the data section) and pushes its size (via a tag)
    /// on the stack. @returns the assembly item corresponding to the pushed subroutine, i.e. its offset.
    eth::AssemblyItem addSubroutine(eth::Assembly const& _assembly) { return m_asm.appendSubSize(_assembly); }
    /// Pushes the size of the final program
    void appendProgramSize() { return m_asm.appendProgramSize(); }
    /// Adds data to the data section, pushes a reference to the stack
    eth::AssemblyItem appendData(bytes const& _data) { return m_asm.append(_data); }

    /// Append elements to the current instruction list and adjust @a m_stackOffset.
    CompilerContext& operator<<(eth::AssemblyItem const& _item) { m_asm.append(_item); return *this; }
    CompilerContext& operator<<(eth::Instruction _instruction) { m_asm.append(_instruction); return *this; }
    CompilerContext& operator<<(u256 const& _value) { m_asm.append(_value); return *this; }
    CompilerContext& operator<<(bytes const& _data) { m_asm.append(_data); return *this; }

    eth::Assembly const& getAssembly() const { return m_asm; }
    void streamAssembly(std::ostream& _stream) const { _stream << m_asm; }
    bytes getAssembledBytecode(bool _optimize = false) { return m_asm.optimise(_optimize).assemble(); }

private:
    eth::Assembly m_asm;

    /// Magic global variables like msg, tx or this, distinguished by type.
    std::set<Declaration const*> m_magicGlobals;
    /// Other already compiled contracts to be used in contract creation calls.
    std::map<ContractDefinition const*, bytes const*> m_compiledContracts;
    /// Size of the state variables, offset of next variable to be added.
    u256 m_stateVariablesSize = 0;
    /// Storage offsets of state variables
    std::map<Declaration const*, u256> m_stateVariables;
    /// Offsets of local variables on the stack (relative to stack base).
    std::map<Declaration const*, unsigned> m_localVariables;
    /// Sum of stack sizes of local variables
    unsigned m_localVariablesSize;
    /// Labels pointing to the entry points of funcitons.
    std::map<Declaration const*, eth::AssemblyItem> m_functionEntryLabels;
};

}
}