UltraVaultRateProvider Code Style Findings

UVR-01C: Ineffectual Usage of Safe Arithmetics

Type	Severity	Location
Language Specific		UltraVaultRateProvider.sol: • I-1: L179 • I-2: L181

Description:

The linked mathematical operation is guaranteed to be performed safely by logical inference, such as surrounding conditionals evaluated in require checks or if-else constructs.

Example:

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178} else if (fromDecimals < toDecimals) {
179    return amount * 10 ** (toDecimals - fromDecimals);
180} else {
181    return amount / 10 ** (fromDecimals - toDecimals);
182}

Recommendation:

Given that safe arithmetics are toggled on by default in pragma versions of 0.8.X, we advise the linked statement to be wrapped in an unchecked code block thereby optimizing its execution cost.

Alleviation (28f27853965de07fb79f4f2b5fed696d35120032):

Both decimal difference calculations have been wrapped in an unchecked code block, optimizing the code's gas cost.

UVR-02C: Inexecutable Code

Type	Severity	Location
Gas Optimization		UltraVaultRateProvider.sol:L176-L178

Description:

The first case of the referenced if-else-if conditional chain will never be executed as the UltraVaultRateProvider::_convertDecimals function is solely invoked whenever the decimals differ between them.

Example:

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170/// @dev Helps with decimals accounting
171function _convertDecimals(
172    uint256 amount, 
173    uint8 fromDecimals, 
174    uint8 toDecimals
175) internal pure returns (uint256) {
176    if (fromDecimals == toDecimals) {
177        return amount;
178    } else if (fromDecimals < toDecimals) {
179        return amount * 10 ** (toDecimals - fromDecimals);
180    } else {
181        return amount / 10 ** (fromDecimals - toDecimals);
182    }
183}

Recommendation:

We advise the code to be optimized based on this premise, reducing its gas cost.

Alleviation (28f27853965de07fb79f4f2b5fed696d35120032):

The code was updated to instead invoke the UltraVaultRateProvider::_convertDecimals function in the decimal equality case as well, addressing this exhibit indirectly.

UVR-03C: Optimization of Yielded Statement

Type	Severity	Location
Gas Optimization		UltraVaultRateProvider.sol:L82-L85

Description:

The UltraVaultRateProvider::isSupported function will evaluate whether data.isPegged is true, yield true in such a case, and yield data.rateProvider != address(0) in any other.

Example:

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82if (data.isPegged) {
83    return true;
84}
85return data.rateProvider != address(0);

Recommendation:

We advise the code to directly yield data.isPegged || data.rateProvider != address(0), optimizing the code's gas cost.

Alleviation (28f27853965de07fb79f4f2b5fed696d35120032):

The code was updated to yield an optimized conditional statement, addressing this exhibit.

UVR-04C: Repetitive Invocations of Storage Offset

Type	Severity	Location
Gas Optimization		UltraVaultRateProvider.sol: • I-1: L91, L100 • I-2: L115, L116 • I-3: L122, L123, L126 • I-4: L132, L133 • I-5: L150, L151

Description:

The referenced statement pairs will end up invoking the UltraVaultRateProvider::_getStorage function multiple times within the same code block redundantly.

Example:

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121function updateRateProvider(address asset, address rateProvider) external onlyOwner {
122    require(asset != baseAsset(), CannotUpdateBaseAsset());
123    require(!supportedAssets(asset).isPegged, AssetNotSupported());
124    require(rateProvider != address(0), InvalidRateProvider());
125
126    _getStorage().supportedAssets[asset].rateProvider = rateProvider;
127    emit RateProviderUpdated(address(asset), rateProvider);
128}

Recommendation:

We advise the UltraVaultRateProvider::_getStorage function to be invoked once, cached to a local variable, and then re-used to optimize the code's gas cost.

Alleviation (28f2785396):

The optimization was solely applied to the example instance, rendering instances 1, 3, 4, and 5 to remain unaddressed.

Alleviation (2d9651dbd7):

All remaining instances have been optimized per our recommendation, addressing this exhibit in full.