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code-423n4 / 2022-10-thegraph-findings

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Gas Optimizations #259

Closed code423n4 closed 1 year ago

code423n4 commented 1 year ago
  1. Splitting require() statements that use && save gas

see https://github.com/code-423n4/2022-01-xdefi-findings/issues/128 which describes the fact that there is a larger deployment gas cost, but with enough runtime calls, the change ends up being cheaper

POC :

https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/governance/Governed.sol#L54 https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/upgrades/GraphProxy.sol#L143

  1. Useage of uint / int smaller than 32 bytes incurs overhead

When using elements that are smaller than 32 bytes, your contract’s gas usage may be higher. This is because the EVM operates on 32 bytes at a time. Therefore, if the element is smaller than that, the EVM must use more operations in order to reduce the size of the element from 32 bytes to the desired size.

POC :

https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/l2/token/GraphTokenUpgradeable.sol#L79

  1. use abi.encodepacked for gas optimization

Changing the abi.encode function to abi.encodePacked can save gas since the abi.encode function pads extra null bytes at the end of the call data, which is unnecessary. Also, in general, abi.encodePacked is more gas-efficient.

POC :

https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/l2/token/GraphTokenUpgradeable.sol#L88 https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/l2/token/GraphTokenUpgradeable.sol#L162

  1. require()/revert() strings longer than 32 bytes cost extra gas

Each extra chunk of byetes past the original 32 which costs 3 gas.

resource : https://gist.github.com/hrkrshnn/ee8fabd532058307229d65dcd5836ddc#consider-having-short-revert-strings

POC :

https://github.com/code-423n4/2022-10-thegraph/blob/main/contracts/upgrades/GraphProxy.sol#L105