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/*
    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 <stack>
#include <utility>
#include <libevmcore/Instruction.h>
#include <libevmcore/Assembly.h>
#include <libsolidity/ASTForward.h>
#include <libsolidity/Types.h>
#include <libdevcore/Common.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, u256 const& _storageOffset, unsigned _byteOffset);
    void addVariable(VariableDeclaration const& _declaration, unsigned _offsetToCurrent = 0);
    void removeVariable(VariableDeclaration const& _declaration);
    void addAndInitializeVariable(VariableDeclaration const& _declaration);

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

    void setStackOffset(int _offset) { m_asm.setDeposit(_offset); }
    void adjustStackOffset(int _adjustment) { m_asm.adjustDeposit(_adjustment); }
    unsigned getStackHeight() const { solAssert(m_asm.deposit() >= 0, ""); return unsigned(m_asm.deposit()); }

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

    eth::AssemblyItem getFunctionEntryLabel(Declaration const& _declaration);
    void setInheritanceHierarchy(std::vector<ContractDefinition const*> const& _hierarchy) { m_inheritanceHierarchy = _hierarchy; }
    /// @returns the entry label of the given function and takes overrides into account.
    eth::AssemblyItem getVirtualFunctionEntryLabel(FunctionDefinition const& _function);
    /// @returns the entry label of a function that overrides the given declaration from the most derived class just
    /// above _base in the current inheritance hierarchy.
    eth::AssemblyItem getSuperFunctionEntryLabel(FunctionDefinition const& _function, ContractDefinition const& _base);
    FunctionDefinition const* getNextConstructor(ContractDefinition const& _contract) const;

    /// @returns the set of functions for which we still need to generate code
    std::set<Declaration const*> getFunctionsWithoutCode();
    /// Resets function specific members, inserts the function entry label and marks the function
    /// as "having code".
    void startFunction(Declaration const& _function);

    ModifierDefinition const& getFunctionModifier(std::string const& _name) const;
    /// Returns the distance of the given local variable from the bottom of the stack (of the current function).
    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;
    /// Converts an offset relative to the current stack height to a value that can be used later
    /// with baseToCurrentStackOffset to point to the same stack element.
    unsigned currentToBaseStackOffset(unsigned _offset) const;
    /// @returns pair of slot and byte offset of the value inside this slot.
    std::pair<u256, unsigned> 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(eth::AssemblyItem::JumpType _jumpType = eth::AssemblyItem::JumpType::Ordinary);
    /// 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); }
    /// Resets the stack of visited nodes with a new stack having only @c _node
    void resetVisitedNodes(ASTNode const* _node);
    /// Pops the stack of visited nodes
    void popVisitedNodes() { m_visitedNodes.pop(); updateSourceLocation(); }
    /// Pushes an ASTNode to the stack of visited nodes
    void pushVisitedNodes(ASTNode const* _node) { m_visitedNodes.push(_node); updateSourceLocation(); }

    /// 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; }
    /// @arg _sourceCodes is the map of input files to source code strings
    /// @arg _inJsonFormat shows whether the out should be in Json format
    void streamAssembly(std::ostream& _stream, StringMap const& _sourceCodes = StringMap(), bool _inJsonFormat = false) const
    {
        m_asm.stream(_stream, "", _sourceCodes, _inJsonFormat);
    }

    bytes getAssembledBytecode(bool _optimize = false) { return m_asm.optimise(_optimize).assemble(); }

    /**
     * Helper class to pop the visited nodes stack when a scope closes
     */
    class LocationSetter: public ScopeGuard
    {
    public:
        LocationSetter(CompilerContext& _compilerContext, ASTNode const& _node):
            ScopeGuard([&]{ _compilerContext.popVisitedNodes(); }) { _compilerContext.pushVisitedNodes(&_node); }
    };

private:
    /// @returns the entry label of the given function - searches the inheritance hierarchy
    /// startig from the given point towards the base.
    eth::AssemblyItem getVirtualFunctionEntryLabel(
        FunctionDefinition const& _function,
        std::vector<ContractDefinition const*>::const_iterator _searchStart
    );
    /// @returns an iterator to the contract directly above the given contract.
    std::vector<ContractDefinition const*>::const_iterator getSuperContract(const ContractDefinition &_contract) const;
    /// Updates source location set in the assembly.
    void updateSourceLocation();

    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;
    /// Storage offsets of state variables
    std::map<Declaration const*, std::pair<u256, unsigned>> m_stateVariables;
    /// Offsets of local variables on the stack (relative to stack base).
    std::map<Declaration const*, unsigned> m_localVariables;
    /// Labels pointing to the entry points of functions.
    std::map<Declaration const*, eth::AssemblyItem> m_functionEntryLabels;
    /// Set of functions for which we did not yet generate code.
    std::set<Declaration const*> m_functionsWithCode;
    /// List of current inheritance hierarchy from derived to base.
    std::vector<ContractDefinition const*> m_inheritanceHierarchy;
    /// Stack of current visited AST nodes, used for location attachment
    std::stack<ASTNode const*> m_visitedNodes;
};

}
}