Gas Optimizations

[code423n4]

Custom Errors Should Be Used For Gas-optimization

Permalinks

1. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/BaseIndex.sol#L29
2. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/BaseIndex.sol#L34
3. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ChainlinkPriceOracle.sol#L51
4. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ChainlinkPriceOracle.sol#L61-L62
5. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ChainlinkPriceOracle.sol#L86
6. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/IndexLogic.sol#L40
7. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/IndexLogic.sol#L76
8. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/IndexLogic.sol#L98
9. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ManagedIndex.sol#L28
10. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ManagedIndex.sol#L40-L48
11. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ManagedIndexReweightingLogic.sol#L29
12. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ManagedIndexReweightingLogic.sol#L52
13. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ManagedIndexReweightingLogic.sol#L58
14. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ManagedIndexReweightingLogic.sol#L62
15. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ManagedIndexReweightingLogic.sol#L85
16. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/ManagedIndexReweightingLogic.sol#L104
17. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/PhuturePriceOracle.sol#L38
18. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/PhuturePriceOracle.sol#L46-L47
19. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/PhuturePriceOracle.sol#L56
20. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/PhuturePriceOracle.sol#L63
21. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/PhuturePriceOracle.sol#L83
22. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/PhuturePriceOracle.sol#L93
23. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/TopNMarketCapIndex.sol#L45
24. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/TopNMarketCapIndex.sol#L55
25. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/TopNMarketCapIndexReweightingLogic.sol#L67
26. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/TrackedIndex.sol#L30
27. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/TrackedIndexReweightingLogic.sol#L38
28. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/UniswapV2PathPriceOracle.sol#L24-L25
29. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/UniswapV2PriceOracle.sol#L46
30. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/UniswapV2PriceOracle.sol#L83
31. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/vToken.sol#L46
32. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/vToken.sol#L59-L60
33. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/vToken.sol#L75
34. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/libraries/IndexLibrary.sol#L29
35. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/libraries/NAV.sol#L49
36. https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/libraries/NAV.sol#L59

Description

Starting from Solidity v0.8.4, there is a convenient and gas-efficient way to explain to users why an operation failed through the use of custom errors. Until now, you could already use strings to give more information about failures (e.g., revert("Insufficient funds.");), but they are rather expensive, especially when it comes to deploy cost, and it is difficult to use dynamic information in them.
Source: https://blog.soliditylang.org/2021/04/21/custom-errors/

Mitigation

Consider using custom errors instead if the contract uses solidity version 0.8.4 or above.

---

Prefix Increments Cost Less Gas Than Suffix Increments

Permalinks

https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/libraries/FullMath.sol#L124

Description

Using a prefix increment ++i costs less gas than a suffix increment i++.

Mitigation

Use prefix increment rather than suffix increment.

---

State Variables Can Be More Packed

Permalinks

https://github.com/code-423n4/2022-04-phuture/blob/594459d0865fb6603ba388b53f3f01648f5bb6fb/contracts/UniswapV2PriceOracle.sol#L29

Description

According to the fact that EVM is a stack-based machine with 256-bits size per stack. When the value are read or written in contract storage, a full 256-bits are read or written; so, packing multiple smaller variables in one slot can save more gas from reading and writing.

Mitigation

uint32 private blockTimestampLast can be declared next to the address public immutable override asset1 pack both variable in the same storage.