Gas saving optimizing storage

[code423n4]

Handle

0x1f8b

Vulnerability details

Impact

Gas saving.

Proof of Concept

• contracts\Types.sol: [TradeVars]

Moving the uint32 dexDetail close to address depositErc20 it's possible to save one slot:

struct TradeVars {
        uint depositValue;  
        IERC20 depositErc20;
        uint32 dexDetail;  // moved
        uint fees;
        uint depositAfterFees;      
        uint tradeSize;
        uint newHeld; 
        uint borrowValue;
        uint token0Price;
        uint totalHeld;
    }

• contracts\Types.sol: [CloseTradeVars]

Moving the uint32 dexDetail; close to bool isPartialClose it's possible to save one slot:

struct CloseTradeVars {
        uint16 marketId;
        bool longToken;
        bool depositToken;
        uint closeRatio;          
        bool isPartialClose;        
        uint32 dexDetail; // moved
        uint closeAmountAfterFees;
        uint borrowed;
        uint repayAmount;     
        uint depositDecrease;
        uint depositReturn;  
        uint sellAmount;
        uint receiveAmount;
        uint token0Price;
        uint fees;
    }

• contracts\periphery\QueryHelper.sol [LiqVars]

Moving marginLimit close to LiqStatus it's possible to save one storage slot.

struct LiqVars {
        LiqStatus status;
        uint32 marginLimit;  // moved
        uint lastUpdateTime;
        uint currentMarginRatio;
        uint cAvgMarginRatio;
        uint hAvgMarginRatio;
    }

• contracts\periphery\QueryHelper.sol [LiquidateVars]

Moving isSellAllHeld and dexDetail it's possible to save 2 slots

struct LiquidateVars {// A variable holder for liquidation process
        uint16 marketId;
        bool longToken;
        bool isSellAllHeld; // moved
        uint32 dexDetail; // moved
        uint borrowed; 
        uint fees;      
        uint penalty; 
        uint remainAmountAfterFees;
        uint depositDecrease;   
        uint depositReturn;       
        uint sellAmount;
        uint receiveAmount;
        uint token0Price;
        uint outstandingAmount;
        uint finalRepayAmount;
    }

• contracts\periphery\QueryHelper.sol [MarginRatioVars]

Moving multiplier and multiplier it's possible to save 2 slots

struct MarginRatioVars {
        address heldToken;
        address sellToken;
        address owner;
        uint16 multiplier; // moved
        uint8 decimals; // moved
        uint held;
        bytes dexData;
        uint price;
        uint cAvgPrice;
        uint hAvgPrice; 
        uint lastUpdateTime;
    }

Tools Used

Manual review.

Recommended Mitigation Steps

Apply the mentioned changes