Sublime contest - rfa's results

gas

#1 Gas improvement on calling SafeERC20.function By removing L26 and calling SafeERC20.function directly at line which calling the function can save gas per call For instance: L754

SafeERC20.safeTransferFrom(_collateralAsset, msg.sender, address(this), _amount);

Can also implemented on SafeMath but not recommended because of readibilty

#2 Using multiple require() instead of && https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/PooledCreditLine.sol#L406 By using multiple require() than && can save execution gas cost.

#3 Gas improvement when validating with isWithinLimits function https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/PooledCreditLine.sol#L368-L386 By removing the isWithinLimits returns and validate directly in it instead of checking the isWithinLimits value == true can save both deployment and execution gas:

function isWithinLimits(
        uint256 _value,
        uint256 _min,
        uint256 _max
    ) internal pure{
        if (_min != 0 && _max != 0) {
            // If both min and max limits exist
            require(_value >= _min && _value <= _max,'ILB1'); //@audit-info validate here
        } else if (_min != 0) {
            // if only min limit exists
            require(_value >= _min);
        } else if (_max != 0) {
            // if only max limit exists
            require(_value <= _max);
        }//@audit-info remove else because no need to validate if both _min && _max == 0
    }
    function foo()external pure{
        isWithinLimits(0,0,0); //@audit-info call it without require()
    }

Currently there are a lot isWithinLimits call in the contract included with require() so it can also save deployment gas by calling the function without require()

#4 Placement of require statement in _limitBorrowedInUSD https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/PooledCreditLine.sol#L394 The require() statement can be place earlier to prevent execution of code above it in case the value of it == false to save gas

#5 Unnecessary withdrawableCollateral MSTORE https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/PooledCreditLine.sol#L777 By calling withdrawableCollateral(_id) directly to L778 without caching it can save gas. The withdrawableCollateral var was just called once in the function:

//@audit-info remove L777
require(_amount <= _withdrawableCollateral(_id), 'WC1');

#6 Relocation of if() condition check https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/PooledCreditLine.sol#L950 Its imposible _max <= _currentDebt == true if _maxPossible == type(uint).max. This condition will only occur inside if(collateralRatio != 0), therefore put it inside the if condition (L944) will prevent if (_maxPossible <= _currentDebt) code read:

if (_collateralRatio != 0) {
            _maxPossible = _totalCollateralToken.mul(_ratioOfPrices).div(_collateralRatio).mul(SCALING_FACTOR).div(10**_decimals);
	if (_maxPossible <= _currentDebt) return 0;
        }

#7 Using > is cheaper than >= https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/LenderPool.sol#L315 1 second difference can be ignored to validate _startTime using > can save gas

#8 Avoiding SLOAD to emit event https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/Verification/twitterVerifier.sol#L209 Use _signerAddress to emit SignerUpdated event

#9 Using at least pragma solidity 0.8.4 https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/PooledCreditLine.sol#L2 Some contract are using SafeMath lib to do math operation. By using pragma 0.8.4, the gas cost can be reduced due to SafeMath by default

#10 caching var.length for loop https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/LenderPool.sol#L670 By caching ids.length to newVar, can save gas:

Uint newVar = ids.lenght
for (uint256 i; i < newVar; ++i)

#11 Store array parameters in calldata https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/LenderPool.sol#L665-L666 using calldata to store ids and amounts can save gas

#12 using -= for gas saving https://github.com/sublime-finance/sublime-v1/blob/46536a6d25df4264c1b217bd3232af30355dcb95/contracts/PooledCreditLine/LenderPool.sol#L681

totalSupply[id] -= amount