Gas Optimizations

[code423n4]

1)Use custom errors rather than revert()/require() strings to save gas

File: 2022-10-thegraph\contracts\governance\Managed.sol: 43 function _notPartialPaused() internal view { 44: require(!controller.paused(), "Paused"); 45: require(!controller.partialPaused(), "Partial-paused"); 46 }

48 function _notPaused() internal view virtual { 49: require(!controller.paused(), "Paused"); 50 }

52 function _onlyGovernor() internal view { 53: require(msg.sender == controller.getGovernor(), "Caller must be Controller governor"); 54 }

56 function _onlyController() internal view { 57: require(msg.sender == address(controller), "Caller must be Controller"); 58 }

103 function _setController(address _controller) internal { 104: require(_controller != address(0), "Controller must be set"); 105 controller = IController(_controller);

File: 2022-10-thegraph\contracts\l2\gateway\L2GraphTokenGateway.sol: 68 modifier onlyL1Counterpart() { 69: require( 70 msg.sender == AddressAliasHelper.applyL1ToL2Alias(l1Counterpart),

97 function setL2Router(address _l2Router) external onlyGovernor { 98: require(_l2Router != address(0), "INVALID_L2_ROUTER"); 99 l2Router = _l2Router;

107 function setL1TokenAddress(address _l1GRT) external onlyGovernor { 108: require(_l1GRT != address(0), "INVALID_L1_GRT"); 109 l1GRT = _l1GRT;

117 function setL1CounterpartAddress(address _l1Counterpart) external onlyGovernor { 118: require(_l1Counterpart != address(0), "INVALID_L1_COUNTERPART"); 119 l1Counterpart = _l1Counterpart;

144 ) public payable override notPaused nonReentrant returns (bytes memory) { 145: require(_l1Token == l1GRT, "TOKEN_NOT_GRT"); 146: require(_amount > 0, "INVALID_ZERO_AMOUNT"); 147: require(msg.value == 0, "INVALID_NONZERO_VALUE"); 148: require(_to != address(0), "INVALID_DESTINATION"); 149

152 (outboundCalldata.from, outboundCalldata.extraData) = parseOutboundData(_data); 153: require(outboundCalldata.extraData.length == 0, "CALL_HOOK_DATA_NOT_ALLOWED"); 154

232 ) external payable override notPaused onlyL1Counterpart nonReentrant { 233: require(_l1Token == l1GRT, "TOKEN_NOT_GRT"); 234: require(msg.value == 0, "INVALID_NONZERO_VALUE"); 235

File: 2022-10-thegraph\contracts\l2\token\L2GraphToken.sol: 35 modifier onlyGateway() { 36: require(msg.sender == gateway, "NOTGATEWAY"); 37 ;

48 function initialize(address _owner) external onlyImpl { 49: require(_owner != address(0), "Owner must be set"); 50 // Initial supply hard coded to 0 as tokens are only supposed

59 function setGateway(address _gw) external onlyGovernor { 60: require(_gw != address(0), "INVALID_GATEWAY"); 61 gateway = _gw;

69 function setL1Address(address _addr) external onlyGovernor { 70: require(_addr != address(0), "INVALID_L1_ADDRESS"); 71 l1Address = _addr;

File: 2022-10-thegraph\contracts\upgrades\GraphProxy.sol: 104 function setAdmin(address _newAdmin) external ifAdmin { 105: require(_newAdmin != address(0), "Cannot change the admin of a proxy to the zero address"); 106 _setAdmin(_newAdmin);

132 (bool success, ) = _implementation().delegatecall(data); 133: require(success); 134 }

140 address _pendingImplementation = _pendingImplementation(); 141: require(Address.isContract(_pendingImplementation), "Implementation must be a contract"); 142: require( 143 _pendingImplementation != address(0) && msg.sender == _pendingImplementation,

156 function _fallback() internal { 157: require(msg.sender != _admin(), "Cannot fallback to proxy target"); 158

File: 2022-10-thegraph\contracts\upgrades\GraphProxyStorage.sol: 61 modifier onlyAdmin() { 62: require(msg.sender == admin(), "Caller must be admin"); 63 ;

File: 2022-10-thegraph\contracts\upgrades\GraphUpgradeable.sol: 23 modifier onlyProxyAdmin(IGraphProxy _proxy) { 24: require(msg.sender == proxy.admin(), "Caller must be the proxy admin"); 25 ;

31 modifier onlyImpl() { 32: require(msg.sender == implementation(), "Caller must be the implementation"); 33 ;

2)USE A MORE RECENT VERSION OF SOLIDITY

Use a solidity version of at least 0.8.2 to get compiler automatic inlining

Use a solidity version of at least 0.8.3 to get better struct packing and cheaper multiple storage reads

Use a solidity version of at least 0.8.4 to get custom errors, which are cheaper at deployment than revert()/require() strings

Use a solidity version of at least 0.8.10 to have external calls skip contract existence checks if the external call has a return value

File: 2022-10-thegraph\contracts\curation\ICuration.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\curation\IGraphCurationToken.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\gateway\BridgeEscrow.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\upgrades\GraphUpgradeable.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\governance\Governed.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\governance\Pausable.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\l2\token\L2GraphToken.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\upgrades\GraphProxyAdmin.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\upgrades\GraphProxyStorage.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\upgrades\GraphProxy.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\governance\Managed.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\l2\token\GraphTokenUpgradeable.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\l2\gateway\L2GraphTokenGateway.sol: 2
3: pragma solidity ^0.7.6; 4 pragma abicoder v2;

File: 2022-10-thegraph\contracts\gateway\L1GraphTokenGateway.sol: 2
3: pragma solidity ^0.7.6; 4 pragma abicoder v2;

File: 2022-10-thegraph\contracts\gateway\GraphTokenGateway.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\curation\IGraphCurationToken.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\gateway\ICallhookReceiver.sol: 8 */ 9: pragma solidity ^0.7.6; 10

File: 2022-10-thegraph\contracts\upgrades\IGraphProxy.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\epochs\IEpochManager.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\governance\IController.sol: 2
3: pragma solidity >=0.6.12 <0.8.0; 4

File: 2022-10-thegraph\contracts\token\IGraphToken.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\rewards\IRewardsManager.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\staking\IStakingData.sol: 2
3: pragma solidity >=0.6.12 <0.8.0; 4

File: 2022-10-thegraph\contracts\curation\ICuration.sol: 2
3: pragma solidity ^0.7.6; 4

File: 2022-10-thegraph\contracts\staking\IStaking.sol: 2
3: pragma solidity >=0.6.12 <0.8.0; 4 pragma abicoder v2;

3)STATE VARIABLES CAN BE PACKED INTO FEWER STORAGE SLOTS If variables occupying the same slot are both written the same function or by the constructor, avoids a separate Gsset (20000 gas). Reads of the variables are also cheaper

File: 2022-10-thegraph\contracts\token\IGraphToken.sol

29 address _owner, 30 address _spender, 31 uint256 _value, 32 uint256 _deadline, 33 uint8 _v, 34 bytes32 _r, 35 bytes32 _s

Variable ordering with 6 slots instead of the current 7:

uint8(1):_v, address(20):_owner, address(20):_spender, uint256(32):_value, uint256(32):_deadline bytes32(32):_r, bytes32(32):_s

4)Splitting require() statements that use && saves gas

Instead of using the && operator in a single require statement to check multiple conditions,using multiple require statements with 1 condition per require statement will save 3 GAS per && : // Before require(result >= MIN_64x64 && result <= MAX_64x64); // After require(result >= MIN_64x64); require(result <= MAX_64x64);

File: 2022-10-thegraph\contracts\gateway\L1GraphTokenGateway.sol:

142: require(_escrow != address(0) && Address.isContract(_escrow), "INVALID_ESCROW");

File: 2022-10-thegraph\contracts\governance\Governed.sol 55,43: pendingGovernor != address(0) && msg.sender == pendingGovernor, "Caller must be pending governor" );

File: 2022-10-thegraph\contracts\staking\Staking.sol 369,37: require(_alphaNumerator > 0 && _alphaDenominator > 0, "!alpha");

File: 2022-10-thegraph\contracts\upgrades\GraphProxy.sol 142,48: require( 143,50: _pendingImplementation != address(0) && msg.sender == _pendingImplementation, "Caller must be the pending implementation" );

5) USING > 0 COSTS MORE GAS THAN != 0 WHEN USED ON A UINT IN A REQUIRE() STATEMENT

This change saves 6 gas per instance

File: 2022-10-thegraph\contracts\gateway\L1GraphTokenGateway.sol: 200 require(_l1Token == address(token), "TOKEN_NOT_GRT"); 201: require(_amount > 0, "INVALID_ZERO_AMOUNT"); 202 require(_to != address(0), "INVALID_DESTINATION");

216 ); 217: require(maxSubmissionCost > 0, "NO_SUBMISSION_COST");

File: 2022-10-thegraph\contracts\l2\gateway\L2GraphTokenGateway.sol:

146: require(_amount > 0, "INVALID_ZERO_AMOUNT");