Gas Optimizations

[code423n4]

GAS OPT

1. Title : Using ++i than i++ for saving more gas

Using i++ instead ++i for all the loops, the variable i is incremented using i++. It is known that implementation by using ++i costs less gas per iteration than i++.

Tools Used

Manual Review

Occurances

main/contracts/Booster.sol#L329                for (uint256 i = 0; i < poolInfo.length; i++) {
main/contracts/BaseRewardPool.sol#L282         for (uint256 i = 0; i < poolInfo.length; i++) { 
main/contracts/BaseRewardPool.sol#L176         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L199         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L218         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L244         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L282         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/VE3DRewardPool.sol#L148         for (uint256 i = 0; i < rewardTokens.length(); i++) {
main/contracts/VE3DRewardPool.sol#L214         for (uint256 i = 0; i < length; i++) {
main/contracts/VE3DRewardPool.sol#L238         for (uint256 i = 0; i < length; i++) {
main/contracts/VE3DRewardPool.sol#L257         for (uint256 i = 0; i < length; i++) {
main/contracts/VE3DRewardPool.sol#L281         for (uint256 i = 0; i < rewardTokens.length(); i++) {
main/contracts/VE3DRewardPool.sol#L326         for (uint256 i = 0; i < length; i++) {
main/contracts/VoterProxy.sol#L217             for (uint256 i = 0; i < _tokenVote.length; i++) {

2. Title : change uint256 i = 0 into uint256 i for saving more gas

using this implementation can saving more gas for each loops.

Tool Used

Manual Review

Recommended Mitigation

Change it

Occurances

main/contracts/Booster.sol#L329                for (uint256 i = 0; i < poolInfo.length; i++) {
main/contracts/BaseRewardPool.sol#L282         for (uint256 i = 0; i < poolInfo.length; i++) { 
main/contracts/BaseRewardPool.sol#L176         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L199         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L218         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L244         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L282         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/VE3DRewardPool.sol#L148         for (uint256 i = 0; i < rewardTokens.length(); i++) {
main/contracts/VE3DRewardPool.sol#L214         for (uint256 i = 0; i < length; i++) {
main/contracts/VE3DRewardPool.sol#L238         for (uint256 i = 0; i < length; i++) {
main/contracts/VE3DRewardPool.sol#L257         for (uint256 i = 0; i < length; i++) {
main/contracts/VE3DRewardPool.sol#L281         for (uint256 i = 0; i < rewardTokens.length(); i++) {
main/contracts/VE3DRewardPool.sol#L326         for (uint256 i = 0; i < length; i++) {
main/contracts/VoterProxy.sol#L217             for (uint256 i = 0; i < _tokenVote.length; i++) {

3. Title : Caching array length can saving more gas

This implementation can be saving more gas, since if caching the array length is more gas efficient.
just because access to a local variable in solidity is more efficient.

Tool Used

Manual Review

Occurances

main/contracts/Booster.sol#L329                for (uint256 i = 0; i < poolInfo.length; i++) {
main/contracts/BaseRewardPool.sol#L282         for (uint256 i = 0; i < poolInfo.length; i++) { 
main/contracts/BaseRewardPool.sol#L176         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L199         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L218         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L244         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/BaseRewardPool.sol#L282         for (uint256 i = 0; i < extraRewards.length; i++) {
main/contracts/VE3DRewardPool.sol#L148         for (uint256 i = 0; i < rewardTokens.length(); i++) {
main/contracts/VE3DRewardPool.sol#L281         for (uint256 i = 0; i < rewardTokens.length(); i++) {
main/contracts/VoterProxy.sol#L217             for (uint256 i = 0; i < _tokenVote.length; i++) {

4. Title : Using > 0 costs more gas than != 0 when used on uints in a require() statement

1.) File : contracts/VeAssetDepositor.sol (Line.132)

        require(_amount > 0, "!>0");

2.) FIle : contracts/BaseRewardPool.sol (Line.215)

        require(amount > 0, "RewardPool : Cannot withdraw 0");

3.) File : contracts/BaseRewardPool.sol (Line.173)

        require(_amount > 0, "RewardPool : Cannot stake 0");

4.) File : contracts/BaseRewardPool.sol (Line.196)

        require(_amount > 0, "RewardPool : Cannot stake 0");

5.) contracts/BaseRewardPool.sol (Line.215)

        require(amount > 0, "RewardPool : Cannot withdraw 0");

6.) File : contracts/VE3DRewardPool.sol (Line.210)

        require(_amount > 0, "RewardPool : Cannot stake 0");

7.) File : contracts/VE3DRewardPool.sol (Line.234)

        require(_amount > 0, "RewardPool : Cannot stake 0");

8.) File : contracts/VE3DRewardPool.sol (Line.254)

        require(_amount > 0, "RewardPool : Cannot stake 0");

5. Title : Saving gas by removing = 0

This implementation code can be saving more gas by removing = 0, it because If a variable was not set/initialized, it is assumed to have default value to 0

Tool Used

Manual Review

Mitigation Step

Remove = 0

Occurances

main/contracts/BaseRewardPool.sol#L274             rewards[_account] = 0;
main/contracts/VeAssetDepositor.sol#L28             uint256 public incentiveVeAsset = 0;
main/contracts/VeAssetDepositor.sol#L119            incentiveVeAsset = 0;
main/contracts/VeAssetDepositor.sol#L141            incentiveVeAsset = 0;
main/contracts/BaseRewardPool.sol#L66               uint256 public periodFinish = 0;
main/contracts/BaseRewardPool.sol#L67               uint256 public rewardRate = 0;
main/contracts/BaseRewardPool.sol#L70                uint256 public queuedRewards = 0;
main/contracts/BaseRewardPool.sol#L71                uint256 public currentRewards = 0;
main/contracts/BaseRewardPool.sol#L72                uint256 public historicalRewards = 0;
main/contracts/VE3DRewardPool.sol#L361             rewardTokenInfo[_rewardToken].queuedRewards = 0;

6. Title : Value can be set as immutable

This can be set as immutable for saving more gas

Tool Used

Remix

Recommended Mitigation

add immutable

Occurances

1.) File : contracts/VeTokenMinter.sol (Line.16)

    ERC20 public veToken;

2.) File : contracts/VoterProxy.sol (Line.31)

    IVoteEscrow.EscrowModle public escrowModle;

3.) File : contracts/BaseRewardPool.sol (Lines.55-56)

    IERC20 public rewardToken;
    IERC20 public stakingToken;

4.) File : contracts/BaseRewardPool.sol (Lines.62-63)

    address public operator;
    address public rewardManager;

7. reorder function addExtraReward for saving more gas

https://github.com/code-423n4/2022-05-vetoken/blob/main/contracts/BaseRewardPool.sol#L121-L129

this implementation below can be saving +- 200 gas

Tool Used

Manual Review, Remix

Recommended Mitigation

    function addExtraReward(address _reward) external returns (bool) {
        require(_reward != address(0), "!reward setting"); // => this can be excecuted first
        require(msg.sender == rewardManager, "!authorized");
        require(extraRewards.length < EXTRA_REWARD_POOLS, "!extra reward pools exceed");


        extraRewards.push(_reward);
        emit ExtraRewardAdded(_reward);
        return true; 
    }
// 3676423 before changed 
// 3676216 after changed (saving +- 200 gas)

8. Title : public functions should be declared external for saving more gas

1.) File : contracts/BaseRewardPool.sol (Line.196)

    function stakeFor(address _for, uint256 _amount) public updateReward(_for) returns (bool) {

2.) File : contracts/Booster.sol (Line.434)

    function withdrawAll(uint256 _pid) public returns (bool) {

3.) File : contracts/VeTokenMinter.sol (Line.32)

    function addOperator(address _newOperator) public onlyOwner {

4.) File : contracts/VeTokenMinter.sol (Line.36)

        function removeOperator(address _operator) public onlyOwner {

9. Title Caching in calldata instead of memory

1.) File : contracts/VoterProxy.sol (Line.199)

    function isValidSignature(bytes32 _hash, bytes memory) public view returns (bytes4) {

[GalloDaSballo]

6 Immutables * 2100 = 12600

Rest is roughly another 1k

13600