Gas Optimizations - Githubissues

code-423n4 / 2022-05-opensea-seaport-findings

1 stars 0 forks source link

Gas Optimizations #86

Open code423n4 opened 2 years ago

code423n4 commented 2 years ago

Redundant initialisation with default value

Some variables are initialised with their default values which cause unnecessary gas consumption

Lines of code

https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/BasicOrderFulfiller.sol#L948 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/BasicOrderFulfiller.sol#L1040 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/conduit/Conduit.sol#L66 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/conduit/Conduit.sol#L130 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/CriteriaResolution.sol#L56 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/CriteriaResolution.sol#L166 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/CriteriaResolution.sol#L184 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/CriteriaResolution.sol#L199 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L181 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L247 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L291 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L373 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L470 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L473 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L498 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L577 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L598 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L621 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L751 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L754 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderFulfiller.sol#L217 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderFulfiller.sol#L306 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderFulfiller.sol#L471 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderValidator.sol#L272 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderValidator.sol#L350 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/AmountDeriver.sol#L44

Prefix increment/decrements are cheaper than postfix increment/decrements

Lines of code

https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L229

private functions are cheaper than internal functions.

Some of the internal functions are never called from the inherited contracts. Hence, their visibility can be changed to private.

Lines of code

https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/BasicOrderFulfiller.sol#L940 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/BasicOrderFulfiller.sol#L1021 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/conduit/Conduit.sol#L174 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/conduit/ConduitController.sol#L480 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/conduit/ConduitController.sol#L496 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/ConsiderationBase.sol#L131 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/CriteriaResolution.sol#L223 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/CriteriaResolution.sol#L245 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/Executor.sol#L413 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/Executor.sol#L456 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/Executor.sol#L502 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/Executor.sol#L558 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/Executor.sol#L597 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/FulfillmentApplier.sol#L202 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/FulfillmentApplier.sol#L497 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L163 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L451 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L567 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderCombiner.sol#L741 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderFulfiller.sol#L161 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/OrderValidator.sol#L451 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/SignatureVerification.sol#L120 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/ZoneInteraction.sol#L61 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/ZoneInteraction.sol#L160

memory arguments can be changed to calldata

It is cheaper to use calldata for the read-only arguments of external functions because then intermediate memory operations are avoided.

Lines of code

https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/Consideration.sol#L301 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/Consideration.sol#L385

Booleans are more expensive than uint256

It is more expensive to operate using booleans because before every write operation an SLOAD is executed to read the contents of the slot. Therefore, it is cheaper to use uint256 instead of bool. On the other hand, using bool is better for the code readability. Hence, it is a tradeoff to be decided by the developers. For example; _channels mapping in Conduit.sol: https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/conduit/Conduit.sol#L33

    mapping(address => bool) private _channels;

can be changed to: mapping(address => uint) private _channels;

Then updateChannel() can set _channels[channel] = isOpen; //@audit isOpen can be uint with possible values of 1 and 2 Where isOpen can take values 1 and 2 for open and closed. This way more gas can be saved because SSTORE from 0 to a nonzero value costs 20000 gas, whereas SSTORE from nonzero to nonzero costs 5000 gas.

Lines of code

https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/conduit/Conduit.sol#L33 https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/conduit/Conduit.sol#L163

HardlyDifficult commented 2 years ago

Redundant initialisation with default value The optimizer should take care of this automatically.
Prefix increment/decrements are cheaper than postfix increment/decrements True, small savings
private functions are cheaper than internal functions. Private vs internal improves code readability but shouldn't impact gas costs (unlike public vs internal for example).
memory arguments can be changed to calldata True, however they appeared to have intentionally used memory here in order to encourage code reuse - e.g. https://github.com/code-423n4/2022-05-opensea-seaport/blob/main/contracts/lib/Consideration.sol#L230 where they are generating the array.