Gas Optimizations

[code423n4]

Lot of function in all contracts could be external instead of public

Problem:

Most of them should not be pulic as they are not used in the contract. Plus, it could save gas to have them external and it's a best practice.

Examples:

• addMinter, removeMinter in DBR.sol
• expansion , contraction in Fed.sol
• a lot in all contracts

Suggestion:

If function is not used inside the contract, change its visibility from public to external

In DolaBorrowingRights.sol name , symbol could be immutable

Problem:

These two variables are never changed and should not, having them immutable could save gas and would make sure they will never be modified.

Suggestion:

Put name , symbol as immutable in DolaBorrowingRights.sol

in DBR.sol the function transfer, transferFrom and burn could be optimized by adding one line in the unchecked bloc

Problem:

For example in transfer , we have:

    ``require(balanceOf(msg.sender) >= amount, "Insufficient balance");

    balances[msg.sender] -= amount;
    unchecked {
        balances[to] += amount;
    }``

The second line could be put in the unchecked bloc as the previous require ensures that it won't underflow.

Suggestion:

In the 3 functions, add the previous line in the unchecked bloc to save a little bit of gas.

In Market.sol and DBR.Sol some code is called two times.

• these require are called 2 times: 1st by market, then in forcereplenish

• // xcz this replenishmentCost is computed in onforcereplenish too

Problem:

In forceReplenish , the 2 requires, are also called in onForceReplenish . In forceReplenish , replenishmentCost computation, is also called in onForceReplenish .

Suggestion:

Code could be refactored to execute these codes only one time. For example, passing the result of the computation as a parameter to onForceReplenish .

In Market.sol , function liquidate getPrice is called two times

Problem:

It's computed in getCreditLimitInternal and then directly uint price = oracle.getPrice(address(collateral), collateralFactorBps);

Suggestion

Compute the price only one time and give it as a parameter (for example), could save some gas.

[c4-judge]

0xean marked the issue as grade-c