Gas Optimizations

[code423n4]

1. Obsolete checks

Impact

Function InfinityStaker.getRageQuitAmounts uses require statement to check if uint256 variable totalStaked is bigger or equal to 0. Variable of type uint256 is always bigger or equal to 0 which makes this check completely obsolete.

Proof of Concept

staking/InfinityStaker.so:193     require(totalStaked >= 0, 'nothing staked to rage quit');

Tools Used

Manual Review / VSCode

Recommended Mitigation Steps

It is recommended to remove obsolete check or change it to check if totalStaked value is bigger > than 0.

2. Use scientific notation

Impact

Multiple contracts are using math exponent calculation to express big numbers. This consumes additional gas and its better to use scienfic notation.

Proof of Concept

core/InfinityOrderBookComplication.sol:338:    uint256 PRECISION = 10**4; // precision for division; similar to bps
core/InfinityExchange.sol:1161:    uint256 PRECISION = 10**4; // precision for division; similar to bps
staking/InfinityStaker.sol:237:        (userstakedAmounts[user][Duration.TWELVE_MONTHS].amount * 4)) / (10**18);

Tools Used

Manual Review / VSCode

Recommended Mitigation Steps

It is recommended to use scientific notation, for example: 1e18.

3. Long revert error messages

Impact

Shortening revert error messages to fit in 32 bytes will decrease gas costs for deployment and gas costs when the revert condition has been met.

Proof of Concept

core/InfinityExchange.sol:399:      require(!isUserOrderNonceExecutedOrCancelled[msg.sender][orderNonces[i]], 'nonce already executed or cancelled');
--
staking/InfinityStaker.sol:92:    require(
                          userstakedAmounts[msg.sender][oldDuration].amount >= amount,
                          'insufficient staked amount to change duration'
                        );
--
staking/InfinityStaker.sol:96:    require(newDuration > oldDuration, 'new duration must be greater than old duration');

Tools Used

Manual Review / VSCode

Recommended Mitigation Steps

It is recommended to decrease revert messages to maximum 32 bytes. Alternatively custom error types should be used.

4. Use custom errors instead of revert strings to save gas

Impact

Usage of custom errors reduces the gas cost.

Proof of Concept

Contracts that should be using custom errors:

• InfinityExchange.sol
• InfinityOrderBookComplication.sol
• InfinityStaker.sol
• InfinityToken.sol
• TimelockConfig.sol

Tools Used

Manual Review / VSCode

Recommended Mitigation Steps

It is recommended to add custom errors to listed contracts.

5. No need to explicitly initialize variables with default values

Impact

If a variable is not set/initialized, it is assumed to have the default value (0 for uint, false for bool, address(0) for addresses). Explicitly initializing it with its default value is an anti-pattern and waste of gas.

Proof of Concept

core/InfinityOrderBookComplication.sol:42:    bool _isPriceValid = false;
core/InfinityOrderBookComplication.sol:108:    bool _isPriceValid = false;
core/InfinityOrderBookComplication.sol:76:    for (uint256 i = 0; i < ordersLength; ) {
core/InfinityOrderBookComplication.sol:82:      for (uint256 j = 0; j < nftsLength; ) {
core/InfinityOrderBookComplication.sol:197:    uint256 numConstructedItems = 0;
core/InfinityOrderBookComplication.sol:199:    for (uint256 i = 0; i < nftsLength; ) {
core/InfinityOrderBookComplication.sol:214:    uint256 numTakerItems = 0;
core/InfinityOrderBookComplication.sol:216:    for (uint256 i = 0; i < nftsLength; ) {
core/InfinityOrderBookComplication.sol:244:    uint256 numCollsMatched = 0;
core/InfinityOrderBookComplication.sol:246:    for (uint256 i = 0; i < order2NftsLength; ) {
core/InfinityOrderBookComplication.sol:247:      for (uint256 j = 0; j < order1NftsLength; ) {
core/InfinityOrderBookComplication.sol:289:    uint256 numTokenIdsPerCollMatched = 0;
core/InfinityOrderBookComplication.sol:290:    for (uint256 k = 0; k < item2TokensLength; ) {
core/InfinityOrderBookComplication.sol:291:      for (uint256 l = 0; l < item1TokensLength; ) {
core/InfinityOrderBookComplication.sol:318:    uint256 sum = 0;
core/InfinityOrderBookComplication.sol:320:    for (uint256 i = 0; i < ordersLength; ) {
core/InfinityExchange.sol:148:    for (uint256 i = 0; i < numMakerOrders; ) {
core/InfinityExchange.sol:200:      for (uint256 i = 0; i < ordersLength; ) {
core/InfinityExchange.sol:219:      for (uint256 i = 0; i < ordersLength; ) {
core/InfinityExchange.sol:272:    for (uint256 i = 0; i < numSells; ) {
core/InfinityExchange.sol:308:    for (uint256 i = 0; i < numMakerOrders; ) {
core/InfinityExchange.sol:349:    for (uint256 i = 0; i < ordersLength; ) {
core/InfinityExchange.sol:393:    for (uint256 i = 0; i < numNonces; ) {
core/InfinityExchange.sol:1048:    for (uint256 i = 0; i < numNfts; ) {
core/InfinityExchange.sol:1086:    for (uint256 i = 0; i < numTokens; ) {
core/InfinityExchange.sol:1109:    for (uint256 i = 0; i < numNfts; ) {
core/InfinityExchange.sol:1190:    for (uint256 i = 0; i < numNfts; ) {
core/InfinityExchange.sol:1206:    for (uint256 i = 0; i < numTokens; ) {

Tools Used

Manual Review / VSCode

Recommended Mitigation Steps

It is recommended to remove explicit initializations with default values.

6. Use != 0 instead of > 0 for unsigned integer comparison

Impact

When dealing with unsigned integer types, comparisons with != 0 are cheaper than with > 0.

Proof of Concept

core/InfinityExchange.sol:392:    require(numNonces > 0, 'cannot be empty');

Tools Used

Manual Review / VSCode

Recommended Mitigation Steps

It is recommended to use != 0 instead of > 0.

7. Pack integer values

Impact

Packing integer variables into storage slots saves gas.

Proof of Concept

InfinityStaker.sol:

 17   struct StakeAmount {
 18     uint256 amount;
 19     uint256 timestamp;
 20   }

Tools Used

Manual Review / VSCode

Recommended Mitigation Steps

If amount is not expected to reach specific values it is recommended to pack it in 192 bits and use 64 bits for timestamp.

 17   struct StakeAmount {
 18     uint192 amount;
 19     uint64 timestamp;
 20   }

8. Declare as external

Impact

Functions declared as public that are never called internally within the contract should be marked as external in order save gas (especially in the case where the function takes arguments, since external functions can read arguments directly from calldata instead of allocating memory).

Proof of Concept

InfinityStaker.sol:

• getUserTotalStaked can be set as external - https://github.com/code-423n4/2022-06-infinity/blob/765376fa238bbccd8b1e2e12897c91098c7e5ac6/contracts/staking/InfinityStaker.sol#L154
• getUserTotalVested can be set as external - https://github.com/code-423n4/2022-06-infinity/blob/765376fa238bbccd8b1e2e12897c91098c7e5ac6/contracts/staking/InfinityStaker.sol#L167

Tools Used

Manual Review / VSCode

Recommended Mitigation Steps

It is recommended to change all public functions that are not called internally to external visibility.