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optimizooor #7

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optimizooor #7

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70a004d
optimizooor
Nemusonaneko Oct 11, 2022
d9c7838
Merge branch 'master' into master
Nemusonaneko Oct 11, 2022
a51a029
readd missing iteration
Nemusonaneko Oct 11, 2022
d395180
change how currentDailyBorrows is added
Nemusonaneko Oct 11, 2022
aa970ff
remove optimizations
Nemusonaneko Oct 13, 2022
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31 changes: 21 additions & 10 deletions contracts/LendingPool.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -35,9 +35,9 @@ contract LendingPool is OwnableUpgradeable, ERC721Upgradeable, Clone {
uint public totalBorrowed; // = 0;
string private constant baseURI = "https://nft.llamalend.com/nft/";
uint maxDailyBorrows; // IMPORTANT: an attacker can borrow up to 150% of this limit if they prepare beforehand
uint216 currentDailyBorrows;
uint216 currentDailyBorrows; // would have to borrow more eth than will ever exist daily to break
uint40 lastUpdateDailyBorrows;
mapping(address => bool) public liquidators;
mapping(address => uint) public liquidators;
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have you verified that this is in fact cheaper? i think it should be but havent verified it

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Saves 16168 gas on deployment and a whopping 12 gas on addLiquidator()


event Borrowed(uint currentDailyBorrows, uint newBorrowedAmount);
event ReducedDailyBorrows(uint currentDailyBorrows, uint amountReduced);
Expand Down Expand Up @@ -72,7 +72,11 @@ contract LendingPool is OwnableUpgradeable, ERC721Upgradeable, Clone {
if(toReduce > currentDailyBorrows){
currentDailyBorrows = toAdd;
} else {
currentDailyBorrows = uint216(currentDailyBorrows - toReduce) + toAdd;
unchecked {
// Resulting daily borrow has to be over 10^47 ETH
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this is safu because we know toReduce <= currentDailyBorrows, so (currentDailyBorrows - toReduce) >= 0

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llama agrees

currentDailyBorrows = uint216(currentDailyBorrows - toReduce);
}
currentDailyBorrows += toAdd;
}
require(currentDailyBorrows < maxDailyBorrows, "max daily borrow");
lastUpdateDailyBorrows = uint40(block.timestamp);
Expand Down Expand Up @@ -158,15 +162,20 @@ contract LendingPool is OwnableUpgradeable, ERC721Upgradeable, Clone {
if(sinceLoanStart > maxLoanLength){
interest += ((sinceLoanStart - maxLoanLength)*borrowed)/(1 days);
}
totalBorrowed -= borrowed;
unchecked {
totalBorrowed -= borrowed;
}

_burnWithoutBalanceChanges(loanId, from);

if(sinceLoanStart < (1 days)){
uint until24h;
uint toReduce;
unchecked {
until24h = (1 days) - sinceLoanStart;
// Impossible to overflow since borrowed would overflow before this would
toReduce = (borrowed*until24h)/(1 days);
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}
uint toReduce = (borrowed*until24h)/(1 days);
if(toReduce < currentDailyBorrows){
unchecked {
// toReduce < currentDailyBorrows always so it's fine to restrict to uint216 because currentDailyBorrows is uint216 already
Expand All @@ -188,7 +197,7 @@ contract LendingPool is OwnableUpgradeable, ERC721Upgradeable, Clone {
uint length = loansToRepay.length;
uint totalToRepay = 0;
uint i = 0;
while(i<length){
while(i<length) {
totalToRepay += _repay(loansToRepay[i], from);
unchecked {
i++;
Expand All @@ -200,11 +209,13 @@ contract LendingPool is OwnableUpgradeable, ERC721Upgradeable, Clone {

// Liquidate expired loan
function doEffectiveAltruism(Loan calldata loan, address to) external {
require(liquidators[msg.sender] == true);
require(liquidators[msg.sender] == 1);
uint loanId = getLoanId(loan.nft, loan.interest, loan.startTime, loan.borrowed);
require(_exists(loanId), "loan closed");
require(block.timestamp > (loan.startTime + maxLoanLength), "not expired");
totalBorrowed -= loan.borrowed;
unchecked {
totalBorrowed -= loan.borrowed;
}
_burn(loanId);
nftContract.transferFrom(address(this), to, loan.nft);
}
Expand Down Expand Up @@ -299,12 +310,12 @@ contract LendingPool is OwnableUpgradeable, ERC721Upgradeable, Clone {
}

function addLiquidator(address liq) external onlyOwner {
liquidators[liq] = true;
liquidators[liq] = 1;
emit LiquidatorAdded(liq);
}

function removeLiquidator(address liq) external onlyOwner {
liquidators[liq] = false;
liquidators[liq] = 0;
emit LiquidatorRemoved(liq);
}

Expand Down