proxy.sol

pragma solidity^0.5.0;

contract Registry {
    function getImplementation(address _user) public view returns (address) {}
}

contract ProxyStorage {
    
    Registry registryAddress;
    
}

contract Proxy is ProxyStorage  {
    
    
    bytes32 private constant default_location = keccak256(abi.encodePacked("location"));
    
    function initialize(address _registry) public {
        bytes32 loc = default_location;
        assembly {
            sstore(loc, _registry)
        }
    }
        
    function() external payable {
        address registry;
        bytes32 loc = default_location;
        assembly {
            registry := sload(loc)
        }
        registryAddress = Registry(registry);
        address localImpl = registryAddress.getImplementation(msg.sender);
        assembly {
            let ptr := mload(0x40)
            calldatacopy(ptr, 0, calldatasize)
            let result := delegatecall(gas, localImpl, ptr, calldatasize, 0, 0)
            let size := returndatasize
            returndatacopy(ptr, 0, size)

            switch result
            case 0 { revert(ptr, size) }
            default { return(ptr, size) }
        }
    }

        
}
    
contract ScoreStorage {
    
    uint public score;
    
}

contract Score is ProxyStorage, ScoreStorage {
    
    function setScore(uint _score) public {
        score = _score;
    }
}

contract ScoreV2 is ProxyStorage, ScoreStorage {
        
    function setScore(uint _score) public {
        score = _score + 1;
    }
}