#1 Visibility
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L41
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L9-L18
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L79
change visibility from public to private or internal can save gas. so i recommend to change it.
#2 Default uint
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L46
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L223-L224
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L158
the default value of uint is 0, so remove unnecassary explicit code initializations for default values e.g uint i = 0; to uint i;.
#3 Use storage instead memory
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L205
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L382
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L162
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L191
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L219
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L102
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L734
Use storage instead of memory to reduce the gas fee. I suggest change from
uint [] memory _prices = sample(tokenIn, amountIn, granularity, 1);
to
uint [] storage _prices = sample(tokenIn, amountIn, granularity, 1);
apply to others.
#4 mload cheaper than sload
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L167-L170
Sload are more expensive then Mload and Mstore. Using Mload can reduce the gas fee.
so i suggest to change from
reserve0 = balance0;
reserve1 = balance1;
blockTimestampLast = blockTimestamp;
emit Sync(reserve0, reserve1);
to
reserve0 = balance0;
reserve1 = balance1;
blockTimestampLast = blockTimestamp;
emit Sync(balance0, balance1);
#5 Looping (aritmathic)
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L361
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L207
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L132
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L68
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L90
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L735
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L959
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1106
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1347
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1364
default uint is 0 so remove unnecassary explicit can reduce gas.
caching the array length can reduce gas it caused access to a local variable is more cheap than query storage / calldata / memory in solidity.
pre increment e.g ++i more cheaper gas than post increment e.g i++. i suggest to use pre increment.
#6 Use Calldata
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L361
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L132
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L218
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L381
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L77
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L122
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1407
In the external functions where the function argument is read-only, the function() has an inputed parameter that using memory, if this function didnt change the parameter, its cheaper to use calldata then memory. so we suggest to change it.
#7 Use !=0 instead of >0
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L253
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L272
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L286
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L303
for unsigned integer, >0 is less efficient then !=0, so use !=0 instead of >0.
apply to others.
#8 inequality
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-core.sol#L288
non strict inequality are cheaper than strict one. i suggest to use >= or <= instead of > and < if possible.
#9 Reduce string
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L105
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L387
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L402
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L417
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L452
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/WETH.sol#L29
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L25
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L27
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L45-L47
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L78
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L87
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L133
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1016
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Accountant/AccountantDelegator.sol#L43-L44
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Accountant/AccountantDelegate.sol#L83
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Accountant/AccountantDelegate.sol#L48
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Accountant/AccountantDelegate.sol#L60
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/CNote.sol#L54
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/CNote.sol#L43
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/CNote.sol#L77
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/CNote.sol#L310
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/CNote.sol#L331
reduce string size of error message to bytes 32 can reduce the gas fee. reduce these if possible.
#10 Caching routes.length
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L132-L139
caching routes.length to memory because use multiple times can reduce the gas.
#11 cache the Amounts.length
https://github.com/Plex-Engineer/stableswap/blob/489d010eb99a0885139b2d5ed5a2d826838cc5f9/contracts/BaseV1-periphery.sol#L430
caching Amounts.length to memory because use multiple times and can reduce the gas.
#12 Cache the unigov.proposal.length
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L42
cache unigov.proposal.length to memory because use multiple times and can reduce the gas.
#13 Use req instead &&
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Governance/GovernorBravoDelegate.sol#L42-L45
use require instead of && for efficient gas cost. change it from
require(unigovProposal.targets.length == unigovProposal.values.length &&
unigovProposal.targets.length == unigovProposal.signatures.length &&
unigovProposal.targets.length == unigovProposal.calldatas.length,
"GovernorBravo::propose: proposal function information arity mismatch");
to
require(unigovProposal.targets.length == unigovProposal.values.length, "GovernorBravo::propose:
proposal function information arity mismatch");
require(unigovProposal.targets.length == unigovProposal.signatures.length, "GovernorBravo::propose:
proposal function information arity mismatch");
require(unigovProposal.targets.length == unigovProposal.calldatas.length, "GovernorBravo::propose:
proposal function information arity mismatch");
#14 efficiency if statement
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L269
Boolean variables can be checked within conditionals directly without the use of equality operators to true/false.
i suggest to change this line
if (false) {
maxAssets = maxAssets;
to
if () {
maxAssets = maxAssets;
#15 efficiency require statement !state
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1053
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1063
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1072
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1081
Boolean variables can be checked within conditionals directly without the use of equality operators to true/false.
i suggest to change this line :
require(msg.sender == admin || state == true, "only admin can unpause");
to
require(msg.sender == admin || state, "only admin can unpause");
apply to others.
#16 efficiency if statement !supplier
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/Comptroller.sol#L1357
Boolean variables can be checked within conditionals directly without the use of equality operators to true/false.
i suggest to change this line :
if (suppliers == true) {
updateCompSupplyIndex(address(cToken));
for (uint j = 0; j < holders.length; j++) {
distributeSupplierComp(address(cToken), holders[j]);
to
if (suppliers) {
updateCompSupplyIndex(address(cToken));
for (uint j = 0; j < holders.length; j++) {
distributeSupplierComp(address(cToken), holders[j]);
#17 Caching actualRepayAmount
https://github.com/Plex-Engineer/lending-market/blob/755424c1f9ab3f9f0408443e6606f94e4f08a990/contracts/CNote.sol#L153
cache unigov.proposal.length to memory because use multiple times and can reduce the gas.
i suggest to change from
uint accountBorrowsNew = accountBorrowsPrev - actualRepayAmount;
uint totalBorrowsNew = totalBorrows - actualRepayAmount;
to
uint actualRepayAmount = repayAmount;
uint accountBorrowsNew = accountBorrowsPrev - repayAmount;
uint totalBorrowsNew = totalBorrows - repayAmount;