Gas Optimizations

[code423n4]

1. Functions visibility

• Summary: Functions visibility can be stricter.
• Details: The following functions have public visibility but are not called internally by the contract and thus can have a stricter visibility.
  1. startBridgeTokensViaAnyswap and swapAndStartBridgeTokensViaAnyswap
  2. startBridgeTokensViaAnyswap and swapAndStartBridgeTokensViaAnyswap
  3. swapTokensGeneric
  4. startBridgeTokensViaHop and swapAndStartBridgeTokensViaHop
  5. startBridgeTokensViaNXTP and swapAndStartBridgeTokensViaNXTP
  6. withdraw
• Github Permalinks:
  1. startBridgeTokenViaAnyswap, swapAndStartBridgeTokensViaAnyswap
  2. startBridgeTokensViaCBridge, swapAndStartBridgeTokensViaCBridge
  3. swapTokensGeneric
  4. startBridgeTokensViaHop, swapAndStartBridgeTokensViaHop
  5. startBridgeTokensViaNXTP, swapAndStartBridgeTokensViaNXTP
  6. withdraw
• Mitigation: Change the visibility for the mentioned functions from public to external

2. Unnecessary storage retrieval

• Summary: Storage values retrieved repeatedly in the same function can be cached to optimize gas usage.
• Details: In _startBridge, 6 storage calls are made that can be replaced by chaching 1 variables, reducing gas usage significantly. For example, _bridge(hopData.asset).token can be replaced by s.hopBridges[hopData.asset] where s is stored in memory.
• Github Permalinks: _startBridge, _bridge, and getStorage
• Mitigation: Output of getStorage can be cahced in memory and later calls to _bridge can be replaced with queries to the Storage struct saved in the cache.

[H3xept]

1. Fixed by lifinance/lifi-contracts@26443af0142afdb131b6b3ab278fac29670b7b0e
   Duplicate of QA Report #197

[H3xept]

Re Unnecessary storage retrieval

Duplicate of #196