Ethos Reserve contest - pavankv's results

1. Use bytes instead of string to save gas .:-

If string called then it cost more gas than bytes data types . So try change to bytes32 and compare if any access control purpose .

code snippet:- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/BorrowerOperations.sol#L21 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LQTY/CommunityIssuance.sol#L19 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LQTY/LQTYStaking.sol#L23

B . Instead of declare string and convert that to bytes in line 120 and 121 of LUSDToken.sol and assigning to it again bytes variables .So it can directly declare to bytes and assign to bytes directly without converting from string to bytes which save conversion gas and when we call bytes data types it consumes less gas .

code snippet of conversion :- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L120 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L121

code snippet of assigning to bytes32 variables only :- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L123 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L124

code snippet of string variables :- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L34 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L32

Code snippet of calling string datatypes which consume more gas calling bytes32 datatypes:- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L399

Please let me know if want poc of caliing bytes32 data types is cheaper than string data types .

recommendation :- change to bytes32 immutable stringName = keccak256("string can here");

2 .Use named returns for local variables where it is possible :-

code snippet :- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1050 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1063 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1073 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1134 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1149 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1227 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1422 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1571 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1578 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1585 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/TroveManager.sol#L1592

3 .Re-arrange the state variable to save slots :-

Below mentioned values of data types can fit into uint128 also .So try to change and save slot gas .

code snippet:- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/ActivePool.sol#L49-L54 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L27 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L28

4 . Instead of one value in struct declare as state variable :-

code snippet:- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/StabilityPool.sol#L175

5 . split require statement to save gas :-

Because each [&&] and opcode use 3 gas

code snippet:- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L348 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L349 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L353 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LUSDToken.sol#L354

6 . Use immutable for keccak operation variables :-

Because when we call data types which have keccak operation it will consumes gas each time for conversion of string to bytes so if declare in immutable it will take once contract deployment .

code snippet:- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L73 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L74 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L75 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L76 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/abstract/ReaperBaseStrategyv4.sol#L49 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/abstract/ReaperBaseStrategyv4.sol#L50 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/abstract/ReaperBaseStrategyv4.sol#L51 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/abstract/ReaperBaseStrategyv4.sol#L52

7 . Use x = x+y instead x+=y while dealing with state variables only :-

Here state varible is totalAllocBPS code snipet:- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L168 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L194 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L196 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L214 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Vault/contracts/ReaperVaultV2.sol#L445

8. Using Solidity version 0.8.17 will provide an overall gas optimization

Using at least 0.8.10 will save gas due to skipped extcodesize check if there is a return value. Currently the contracts are compiled using version 0.8.7 (Foundry default). It is easily changeable to 0.8.17 using the command sed -i 's/0.8.7/^0.8.0/' test/*.sol && sed -i '4isolc = "0.8.17"' foundry.toml. This will have the following total savings obtained by forge snapshot --diff | tail -1

codes snippet:- https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/CollateralConfig.sol#L3 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/ActivePool.sol#L3 https://github.com/code-423n4/2023-02-ethos/blob/main/Ethos-Core/contracts/LQTY/CommunityIssuance.sol#L3 and all scoped files