Lybra Finance - ayo_dev's results

1. Use Uint256 to store Constants instead of Bytes32

Instead of using a bytes32 to store keccack256 hash as state variable, we can instead use a uint256 to store the state variables examples can be found in solady contract https://github.com/Vectorized/solady/blob/8c751db06e614e26e6acb9b385b463feef5e3a9f/src/tokens/ERC20.sol#L51

contract test {//deployment cost 113364 gas, 
    uint256 public constant _TRANSFER_EVENT_SIGNATURE =
        0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef; //
}

contract test {//deployment cost 121071 gas, 
    bytes32 public constant _TRANSFER_EVENT_SIGNATURE =
        keccak256(bytes("Transfer(address,address,uint256)"));
}

one reason this might be is because i think solidity use extra operations to check whether the bytes are valid bytes but does not do this for uint256 NOTE: uint256 is equal to bytes32 they both contain 32 bytes and can be typecasted and vice versa an example of this problem can be found in the LybraConfigurator contract

Instances in the code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L76 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L77 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L78 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/GovernanceTimelock.sol#L10 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/GovernanceTimelock.sol#L11

2. Change The Visibility of the Bytes32 constant to private from public

There's no reason to use public on bytes32 constant variable, when you use public for a function solidity creates a getter for that variable similar to a function and this leads to more gas usage

contract test { //Deployment cost: 77126 gas
    bytes32 private constant _TRANSFER_EVENT_SIGNATURE =
        keccak256(bytes("Transfer(address,address,uint256)"));
}

contract test { //Deployment cost: 121071 gas
    bytes32 public constant _TRANSFER_EVENT_SIGNATURE =
        keccak256(bytes("Transfer(address,address,uint256)"));
}

this saves us 5000+ in deployment cost this same problem can be found in LybraConfigurator contract

Instances in the code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L76 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L77 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L78 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/GovernanceTimelock.sol#L13 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/GovernanceTimelock.sol#L12

3.Use Custom Errors to instead of require

This chat from overflow explains why custom errors are more efficient than require statement https://ethereum.stackexchange.com/questions/123381/when-should-i-use-require-vs-custom-revert-errors This example can be in the LybraConfigurator and all other part of the code

Instances in Code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L200 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L214 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L225 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/LybraGovernance.sol#L78 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/LybraGovernance.sol#L79 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/LybraGovernance.sol#L82

4.Do not Initialize variables in loops to zero

by default variables in solidity are zero by default, there is no reason to initialize them to zero again especially in a loop

contract test {//Deployment cost : 180927 gas 
    function tests(uint[] calldata arr) public view {// runtime gas: 1220 gas
       for(uint i; i < arr.length; ++i){
           
       }
    }
}

contract test {//Deployment cost : 180927 gas 
    function tests(uint[] calldata arr) public view {// runtime gas: 1230 gas
       uint t;
       for(uint i = 0; i < arr.length; ++i){
           t = i;
       }
    }
}

this saves us 10+ in gas fees this same problem can be found in LybraConfigurator contract Instances in code https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L236 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/EUSDMiningIncentives.sol#L94 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/EUSDMiningIncentives.sol#L138

5. Consider using named return Variables

Named return variables is the cheapest method form of return you can do(apart from the returning using assembly - not advisible)

contract test {//Deployment cost : 178449 gas
    function tests(uint[] calldata arr) public pure returns(uint r){// runtime gas : 696 gas
      r = arr[0];
    }
}

contract test {//Deployment cost : 178449 gas
    function tests(uint[] calldata arr) public pure returns(uint){// call gas : 696 gas
      return arr[0];
    }
}

Instances in code Note: all functions in the codebase have this issue

6. Replace return type bool with uint256

Bools in solidity are 1s and 0s by default, 1 for true and 0 for false, the thing is bools can also be called uint8, yes every bool type is uint8 meaning they are one byte, so everytime you return a type as uint8 or bool, solidity will have to perform extra operations to shift the bits and make sure they fit into a uint8 type

contract test {//Deploymnet cost : 107133 gas
    function tests() public view returns(bool r){//runtime cost : 321 gas
       assembly{
           r := 1
       }
     }
}

contract test {//Deployment cost: 106637
    function tests() public view returns(uint256 r){//runtime cost : 315 gas
       assembly{
           r := 1
       }
     }
}

turns out replacing bool with bool with a uint256 saves you 900+ in deployment cost and 6+ in runtime cost this can be found in the Governance Timelock contract

Instances in code https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L360 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L348 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L268

7.Make Mappings Private

A lot of states variables could be made private for example in the Governance Timelock contract a lot of mappings should have been made private instead of public, when you make a state variable

contract test {//deployment cost: 126699 gas
    mapping(uint => bool) private num;
    function tests(uint r) public  {//write cost for initialization: 50408 gas
        num[r] = true;              //write cost after initialization: 27523 gas
     }
}

contract test {//deployment cost: 166630 gas
    mapping(uint => bool) public num;
    function tests(uint r) public  {//write cost for initialization: 50434 gas
        num[r] = true;              //write cost after initialization: 27549 gas
     }
}

from the above we save over 4000+ in gas during deployment and 34+ in gas during runtime

Instances in code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/LybraGovernance.sol#L33 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/stakerewardV2pool.sol#L33 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/stakerewardV2pool.sol#L35 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/stakerewardV2pool.sol#L36 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/ProtocolRewardsPool.sol#L33 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/ProtocolRewardsPool.sol#L35 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/ProtocolRewardsPool.sol#L36

8. Offchain computation

A lot of computation could have been done offchain, instead they were done onchain and this led to the increase of gas, for example in the keccak256 computaion and a lot of constants multiplication computation, with this we could have saved 100+ in gas if they were done off chain by the dev and simply brought on chain, one way we should actually do this is use uint256 instead of keccak256, but that would mean rewriting the contract anyway

contract test {//Deployment in gas cost: 164429 gas
    function tests() public  {//call gas cost: 24428 gas
        check(keccak256("timelock"), address(this));
     }

     function check(bytes32, address _sender) public view {

     }
}

contract test {//Deployment in gas cost: 165167 gas
    function tests() public {
        check(
            0x3b101b2aa2577f8e2ab6b4a2521a67e48b95c9db8515c5daa4e493b8e4be8a8e,
            address(this)
        );
    }

    function check(bytes32, address _sender) public view {}
}

Instances in code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/pools/LybraRETHVault.sol#L42 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/esLBRBoost.sol#L26 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/esLBRBoost.sol#L27 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/esLBRBoost.sol#L28 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/esLBRBoost.sol#L29 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/EUSDMiningIncentives.sol#L181

9. Use byte32 as return type where string length is more than 32

when you use strings as return types, then you definitely have to write to memory since it's a dynamic type, however if we were bytes32 type it goes directly to the stack and saves us 40+ in gas fees

Instances in code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/LybraGovernance.sol#L151 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/LybraGovernance.sol#L156

10. Use Calldata as Storage instead of memory for function param

storing array in calldata is way cheaper than using memory,

contract test {//deployment cost: 217662 gas
   function reddish(uint[] memory ) public pure {//call cost: 1818 gas

   }
}

contract test {//deployment cost: 117785 gas
   function reddish(uint[] memory ) public pure {//call cost: 452 gas

   }
}

This was conducted using the same param

Instances in code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/LybraGovernance.sol#L106C5-L106C5

11. Some state varaiables could be stored as bytecode using immutables

to read from storage is 5100 in gas but when declared as immutables it only cost 3 gas, with this you get to save over 4997 in gas fees

12. Use Shift left to perform multiplication if one of the number to be multiplied is a power of 2

In one part of the code mul opcode was used to perform multiplication this cost 5 gas, we could have done it using SHL(shift right which would only cost 3 gas)

Instances in code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/pools/base/LybraEUSDVaultBase.sol#L159

13. Remove SafeMath

Starting from solidity version 0.8.0, there's no need for safemath any longer, safemath was introduced to curb overflow and underflow, however from 0.8.0 the compiler can already do this whuch just makes safemath irrelevant and will cause increase in deployment cost

Instances in the code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/token/EUSD.sol#L5 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/token/EUSD.sol#L38

14. Less than or Equal to against constant constant

whenever you are performing the operation <= on a constant, e.g i <= 2 this cost 6+ in gas fees since you would have to use two opcodes that costs 3 each, instead you can simply do i < 3, this two perform the same function but the second part is cheaper since it only uses 3 opcode

Instances in the code: https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L127 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L187 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L214 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L225 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/configuration/LybraConfigurator.sol#L247 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/governance/LybraGovernance.sol#L79 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/EUSDMiningIncentives.sol#L111 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/EUSDMiningIncentives.sol#L106 https://github.com/code-423n4/2023-06-lybra/blob/5d70170f2c68dbd3f7b8c0c8fd6b0b2218784ea6/contracts/lybra/miner/EUSDMiningIncentives.sol#L101