Gas Optimizations - Githubissues

code423n4 commented 2 years ago

Using `bool`s for storage incurs overhead

    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

https://github.com/OpenZeppelin/openzeppelin-contracts/blob/58f635312aa21f947cae5f8578638a85aa2519f5/contracts/security/ReentrancyGuard.sol#L23-L27

mapping(address => mapping(bytes32 => bool)) private _authorizationStates;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/EIP3009.sol#L53

bool internal initialized;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L54

mapping(address => bool) internal minters;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L59

bool internal initialized;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L54

mapping(address => bool) internal minters;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L59

bool public paused = false;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/Pausable.sol#L49

mapping(address => bool) internal blocklisted;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/Blocklistable.sol#L35

bool internal initialized;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L54

mapping(address => bool) internal minters;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L59

mapping(address => bool) internal whitelisted;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L62

`abi.encode()` is less efficient than `abi.encodePacked()`

bytes memory data = abi.encode(

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/EIP3009.sol#L102

bytes memory data = abi.encode(

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/EIP3009.sol#L148

bytes memory data = abi.encode(

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/EIP3009.sol#L183

bytes memory data = abi.encode(

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/EIP2612.sol#L72

`require()` strings longer than 32 bytes cost extra gas

require(oldAllowance >= value, "SafeERC20decreased allowance below zero");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/util/SafeERC20.sol#L76

require(abi.decode(returndata, (bool)), "SafeERC20ERC20 operation did not succeed");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/util/SafeERC20.sol#L96

require(Address.isContract(newImplementation), "ERC1967new implementation is not a contract");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/util/StorageSlot.sol#L23*

require(success, "Addressunable to send value, recipient may have reverted");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/util/Address.sol#L59

require(address(this).balance >= value, "Addressinsufficient balance for call");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/util/Address.sol#L129

require(isContract(target), "Addressstatic call to non-contract");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/util/Address.sol#L157

require(isContract(target), "Addressdelegate call to non-contract");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/util/Address.sol#L184

require(Address.isContract(newImplementation), "ERC1967new implementation is not a contract");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/upgradeability/ERC1967Upgrade.sol#L45

require(slot == _IMPLEMENTATION_SLOT, "ERC1967Upgradeunsupported proxiableUUID");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/upgradeability/ERC1967Upgrade.sol#L92

require(to == msg.sender, "EIP3009caller must be the payee");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/EIP3009.sol#L145

require(!initialized, "FiatTokencontract is already initialized");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L78

require(minters[msg.sender], "FiatTokencaller is not a minter");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L116

require(_to != address(0), "FiatTokenmint to the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L135

require(_amount > 0, "FiatTokenmint amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L136

require(owner != address(0), "ERC20approve from the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L245

require(spender != address(0), "ERC20approve to the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L246

require(from != address(0), "ERC20transfer from the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L309

require(to != address(0), "ERC20transfer to the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L310

require(_amount > 0, "FiatTokenburn amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L368

require(balance >= _amount, "FiatTokenburn amount exceeds balance");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L369

require(!initialized, "FiatTokencontract is already initialized");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L78

require(minters[msg.sender], "FiatTokencaller is not a minter");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L116

require(_to != address(0), "FiatTokenmint to the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L135

require(_amount > 0, "FiatTokenmint amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L136

require(owner != address(0), "ERC20approve from the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L245

require(spender != address(0), "ERC20approve to the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L246

require(from != address(0), "ERC20transfer from the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L309

require(to != address(0), "ERC20transfer to the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L310

require(_amount > 0, "FiatTokenburn amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L368

require(balance >= _amount, "FiatTokenburn amount exceeds balance");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L369

require(msg.sender == pauser, "Pausablecaller is not the pauser");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/Pausable.sol#L63

require(newOwner != address(0), "Ownablenew owner is the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/Ownable.sol#L52

require(msg.sender == _rescuer, "Rescuablecaller is not the rescuer");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/Rescuable.sol#L50

require(!initialized, "FiatTokencontract is already initialized");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L84

require(minters[msg.sender], "FiatTokencaller is not a minter");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L122

require(_to != address(0), "FiatTokenmint to the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L142

require(_amount > 0, "FiatTokenmint amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L143

require(owner != address(0), "ERC20approve from the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L253

require(spender != address(0), "ERC20approve to the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L254

require(from != address(0), "ERC20transfer from the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L319

require(to != address(0), "ERC20transfer to the zero address");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L320

require(_amount > 0, "FiatTokenburn amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L378

require(balance >= _amount, "FiatTokenburn amount exceeds balance");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L379

Using `1e18` rather than `10**18` saves gas

if (_value > 100000 * 10 ** 18) {

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L624

Functions not called by the contract itself should be `external` rather than `public`

function transferOwnership(address newOwner) public virtual onlyOwner {

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/Ownable.sol#L51

function setName2(string memory _name) public {

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2test.sol#L11

Using `> 0` costs more gas than `!= 0` when used on uints in a `require()` statement

require(_amount > 0, "FiatTokenmint amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L136

require(_amount > 0, "FiatTokenburn amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L368

require(_amount > 0, "FiatTokenmint amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L136

require(_amount > 0, "FiatTokenburn amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L368

require(_amount > 0, "FiatTokenmint amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L143

require(_amount > 0, "FiatTokenburn amount not greater than 0");

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L378

It costs more gas to initialize variables to zero than to let the default of zero be applied

uint256 internal totalSupply_ = 0;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L58

minterAllowed[minter] = 0;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.sol#L350

uint256 internal totalSupply_ = 0;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v1/FiatTokenV1.altered.sol#L58

uint256 internal totalSupply_ = 0;

https://github.com/code-423n4/2022-02-jpyc/blob/main/contracts/v2/FiatTokenV2.sol#L58

retocrooman commented 2 years ago

Using bools for storage incurs overhead abi.encode() is less efficient than abi.encodePacked() require() strings longer than 32 bytes cost extra gas

We need to check if these are ture. If they are true we will fix them.

Using 1e18 rather than 10**18 saves gas

We think this is valid. And we will fix this.

Using > 0 costs more gas than != 0 when used on uints in a require() statement It costs more gas to initialize variables to zero than to let the default of zero be applied

This part is the duplicate of #2

thurendous commented 2 years ago

Using bools for storage incurs overhead

Using 1e18 rather than 10**18 saves gas

Fixed and thanks!

Final change can be viewed here.

code-423n4 / 2022-02-jpyc-findings

Gas Optimizations #20

Using `bool`s for storage incurs overhead

`abi.encode()` is less efficient than `abi.encodePacked()`

`require()` strings longer than 32 bytes cost extra gas

Using `1e18` rather than `10**18` saves gas

Functions not called by the contract itself should be `external` rather than `public`

Using `> 0` costs more gas than `!= 0` when used on uints in a `require()` statement

It costs more gas to initialize variables to zero than to let the default of zero be applied

code-423n4 / 2022-02-jpyc-findings

Gas Optimizations #20

Using bools for storage incurs overhead

abi.encode() is less efficient than abi.encodePacked()

require() strings longer than 32 bytes cost extra gas

Using 1e18 rather than 10**18 saves gas

Functions not called by the contract itself should be external rather than public

Using > 0 costs more gas than != 0 when used on uints in a require() statement

It costs more gas to initialize variables to zero than to let the default of zero be applied

Using `bool`s for storage incurs overhead

`abi.encode()` is less efficient than `abi.encodePacked()`

`require()` strings longer than 32 bytes cost extra gas

Using `1e18` rather than `10**18` saves gas

Functions not called by the contract itself should be `external` rather than `public`

Using `> 0` costs more gas than `!= 0` when used on uints in a `require()` statement