Mimo DeFi contest - oyc_109's results

Don't Initialize Variables with Default Value

Description

saves gas

Findings

File: InceptionVaultsCore.sol
218: uint256 insuranceAmount = 0;

cache in variables instead of loading

Description

caching variables that are used multiple times in memory saves gas

Findings

DexAddressProvider.sol:16: for (uint256 i; i < dexes.length; i++) { //@audit cache dexes.length

Prefix increments are cheaper than postfix increments

Description

using prefix increments save gas

Findings

DexAddressProvider.sol:16: for (uint256 i; i < dexes.length; i++) { //@audit use ++i
AdminInceptionVault.sol:108: for (uint8 i = 1; i < _collateralCount + 1; i++) {

calldata instead of memory

Description

Use calldata instead of memory for function parameters saves gas

Findings

DexAddressProvider.sol:13: constructor(IAddressProvider a, Dex[] memory dexes) public {

do not cache variable used only once

Description

for variables only used once, changing it to inline saves gas

Findings

AdminInceptionVault.sol:100: IERC20 asset = IERC20(_a.vaultsData().vaultCollateralType(_vaultId));

File: AdminInceptionVault.sol
138: IERC20 par = IERC20(address(_a.stablex()));

File: InceptionVaultFactory.sol
108: uint256 newId = ++_inceptionVaultCount;

File: InceptionVaultsCore.sol
80: uint256 vaultId = _inceptionVaultsData.vaultId(msg.sender);
137: IERC20 stablex = IERC20(_a.stablex());
151: uint256 newBaseDebt = _a.ratesManager().calculateBaseDebt(newDebt, _cumulativeRate);
155: uint256 collateralValue = _inceptionPriceFeed.convertFrom(v.collateralBalance);
156: uint256 newVaultDebt = _inceptionVaultsData.vaultDebt(_vaultId);
158: bool isHealthy = _a.liquidationManager().isHealthy(collateralValue, newVaultDebt, _vaultConfig.minCollateralRatio);
185: IERC20 stablex = IERC20(_a.stablex());
290: uint256 newCollateralValue = _inceptionPriceFeed.convertFrom(newCollateralBalance);
326: uint256 currentVaultDebt = _inceptionVaultsData.vaultDebt(_vaultId);
332: uint256 newBaseDebt = _a.ratesManager().calculateBaseDebt(remainder, _cumulativeRate);

File: InceptionVaultsDataProvider.sol
78: uint256 increase = _newBaseDebt.sub(_vault.baseDebt);
81: uint256 decrease = _vault.baseDebt.sub(_newBaseDebt);

File: ChainlinkInceptionPriceFeed.sol
46:     uint256 price = getAssetPrice();
47:     uint8 collateralDecimals = ERC20(_inceptionCollateral).decimals();
48:     uint8 parDecimals = ERC20(address(_a.stablex())).decimals(); // Needs re-casting because ISTABLEX does not expose decimals()
49:     uint8 oracleDecimals = _assetOracle.decimals();
50:     uint256 parAccuracy = MathPow.pow(10, parDecimals);
51:     uint256 collateralAccuracy = MathPow.pow(10, oracleDecimals.add(collateralDecimals));

60:     uint256 price = getAssetPrice();
61:     uint8 collateralDecimals = ERC20(_inceptionCollateral).decimals();
62:     uint8 parDecimals = ERC20(address(_a.stablex())).decimals(); // Needs re-casting because ISTABLEX does not expose decimals()
63:     uint8 oracleDecimals = _assetOracle.decimals();
64:     uint256 parAccuracy = MathPow.pow(10, parDecimals);
65:     uint256 collateralAccuracy = MathPow.pow(10, oracleDecimals.add(collateralDecimals));

82:     uint8 eurDecimals = _eurOracle.decimals();
83:     uint256 eurAccuracy = MathPow.pow(10, eurDecimals);

File: GenericMinerV2.sol
236: uint256 multiplier = _getBoostMultiplier(_user);
267:     uint256 mimoReward = currentMimoBalance.sub(_mimoBalanceTracker);
268:     uint256 parReward = currentParBalance.sub(_parBalanceTracker);

284:     uint256 currentBalance = _a.mimo().balanceOf(address(this));
285:     uint256 reward = currentBalance.sub(_mimoBalanceTracker);

298:     uint256 currentBalance = _par.balanceOf(address(this));
299:     uint256 reward = currentBalance.sub(_parBalanceTracker);
300:     uint256 accParAmountPerShare = _accParAmountPerShare.add(reward.rayDiv(_totalStakeWithBoost));

File: PARMinerV2.sol
118: uint256 parBalanceBefore = _par.balanceOf(address(this));

202:     uint256 currentBalance = _par.balanceOf(address(this)).sub(_totalStake);
203:     uint256 reward = currentBalance.sub(_parBalanceTracker);
204:     uint256 accParAmountPerShare = _accParAmountPerShare.add(reward.rayDiv(_totalStakeWithBoost));

336: uint256 multiplier = _getBoostMultiplier(_user);

365: uint256 parReward = currentParBalance.sub(_parBalanceTracker);

379:     uint256 currentBalance = _a.mimo().balanceOf(address(this));
380:     uint256 reward = currentBalance.sub(_mimoBalanceTracker);

do not calculate constants

Description

Due to how constant variables are implemented (replacements at compile-time), an expression assigned to a constant variable is recomputed each time that the variable is used, which wastes some gas.

Consequences: each usage of a "constant" costs ~100gas more on each access (it is still a little better than storing the result in storage, but not much..). since these are not real constants, they can't be referenced from a real constant environment (e.g. from assembly, or from another library )

Findings

File: InceptionVaultsCore.sol
23: uint256 internal constant _MAX_INT = 2**256 - 1; //@audit use type(uint).max) instead

require statements should be checked first

Description

moving the require statement to the top of the function will save gas in the case where requre statement fails

findings

File: InceptionVaultsCore.sol
285: require(_amount <= v.collateralBalance, "IV101");

File: GenericMinerV2.sol
58: require(boostConfig.a >= 1 && boostConfig.d > 0 && boostConfig.maxBoost >= 1, "LM004");