Platform: Code4rena
Start Date: 24/10/2023
Pot Size: $149,725 USDC
Total HM: 7
Participants: 52
Period: 21 days
Judge: ronnyx2017
Total Solo HM: 2
Id: 300
League: ETH
Rank: 23/52
Findings: 1
Award: $162.76
🌟 Selected for report: 0
🚀 Solo Findings: 0
🌟 Selected for report: DavidGiladi
Also found by: 0xhex, 0xta, Collinsoden, JCK, Madalad, SAQ, SY_S, Sathish9098, cheatc0d3, codeslide, hihen, hunter_w3b, jamshed, lsaudit, mgf15, nonseodion, oualidpro, petrichor, sivanesh_808, tala7985, unique, ybansal2403, zabihullahazadzoi
162.763 USDC - $162.76
| Issue | Instances | Estimated Gas Saved | |
|---|---|---|---|
| GAS-1 | 'Don't compare boolean expressions to boolean literals' | 1 | 9 |
| GAS-2 | Increments can be unchecked to save gas | 11 | 660 |
| GAS-3 | array[index] += amount is cheaper than array[index] = array[index] + amount (or related variants) | 2 | 76 |
| GAS-4 | Avoid emitting storage values | 2 | - |
| GAS-5 | Avoid updating storage when the value hasn’t changed | 63 | 50400 |
| GAS-6 | Using this to access functions results in an external call, wasting gas | 6 | 600 |
| GAS-7 | Using bools for storage incurs overhead | 4 | 400 |
| GAS-8 | bytes constants are more efficient than string constants | 11 | - |
| GAS-9 | Cache array length outside of loop | 5 | 15 |
| GAS-10 | Multiple accesses of the same mapping/array key/index should be cached | 12 | 504 |
| GAS-11 | The result of a function call should be cached rather than re-calling the function | 35 | 3500 |
| GAS-12 | State variables that are used multiple times in a function should be cached in stack variables | 69 | 6900 |
| GAS-13 | Use calldata instead of memory for function arguments that do not get mutated | 6 | 1800 |
| GAS-14 | Gas savings can be achieved by changing the model for assigning value to the structure | 8 | 2080 |
| GAS-15 | Multiple address/ID mappings can be combined into a single mapping of an address/ID to a struct, where appropriate | 6 | - |
| GAS-16 | Consider activating via-ir for deploying | 1 | - |
| GAS-17 | Expressions for constant values such as a call to keccak256(), should use immutable rather than constant | 7 | - |
| GAS-18 | Constructors can be marked as payable to save deployment gas | 19 | 399 |
| GAS-19 | Use custom errors rather than revert()/require() strings to save gas | 150 | 7500 |
| GAS-20 | ++i costs less gas than i++, especially when its used in for loops | 7 | 35 |
| GAS-21 | Division by powers of two should use bit shifting | 3 | 60 |
| GAS-22 | Do not shrink Variables | 30 | - |
| GAS-23 | Empty blocks should be removed or emit something | 1 | - |
| GAS-24 | Events should be emitted outside of loops | 1 | - |
| GAS-25 | >=/<= costs less gas than >/< | 63 | 189 |
| GAS-26 | keccak256() hash of literals should only be computed once | 4 | 168 |
| GAS-27 | Don't initialize variables with default value | 19 | - |
| GAS-28 | internal functions only called once can be inlined to save gas | 75 | 1500 |
| GAS-29 | A modifier used only once and not being inherited should be inlined to save gas | 1 | - |
| GAS-30 | Private functions only used once can be inlined to save gas | 2 | 60 |
| GAS-31 | Usage of ints/uints smaller than 32 bytes incurs overhead | 70 | 3850 |
| GAS-32 | Long require/revert strings | 55 | 715 |
| GAS-33 | Reduce gas usage by moving to Solidity 0.8.19 or later | 39 | 39000 |
| GAS-34 | Using a nesting if statement instead of a logical AND(&&) | 14 | 84 |
| GAS-35 | Optimize names to save gas | 40 | 880 |
| GAS-36 | Operator += costs more gas than <x> = <x> + <y> for variables | 8 | 904 |
| GAS-37 | Using private rather than public for constants, saves gas | 31 | 105586 |
| GAS-38 | Change public state variable visibility to private | 42 | - |
| GAS-39 | Redundant state variable getters | 4 | - |
| GAS-40 | Duplicated require()/revert() checks should be refactored to a modifier Or function to save gas | 4 | - |
| GAS-41 | require() or revert() statements that check input arguments should be at the top of the function | 38 | - |
| GAS-42 | Same cast is done multiple times | 4 | - |
| GAS-43 | Use shift Right/Left instead of division/multiplication if possible | 3 | 60 |
| GAS-44 | State variable read in a loop | 21 | 2037 |
| GAS-45 | State variables only set in the constructor should be declared immutable | 54 | 113238 |
| GAS-46 | State variables only set in their definitions should be declared constant | 6 | 12582 |
| GAS-47 | Use uint256(1)/uint256(2) instead of true/false to save gas for changes | 4 | 34200 |
| GAS-48 | Ternary unnecessary | 3 | - |
| GAS-49 | Use != 0 instead of > 0 for unsigned integer comparison | 53 | 212 |
| GAS-50 | Unused named return variables without optimizer waste gas | 9 | 81 |
| GAS-51 | Remove or replace unused state variables | 10 | - |
| GAS-52 | Using bitmap to store bool states can save gas | 1 | - |
| GAS-53 | Use constants instead of type(uintx).max | 20 | - |
| GAS-54 | Using delete instead of setting info struct to 0 saves gas | 5 | - |
| GAS-55 | Use do while loops instead of for loops | 15 | - |
| GAS-56 | unchecked {} can be used on the division of two uints in order to save gas | 35 | 700 |
| GAS-57 | Use unchecked block for safe subtractions | 22 | 1870 |
| GAS-58 | internal functions not called by the contract should be removed | 1 | - |
| GAS-59 | Use assembly to write address/contract type storage values | 26 | 1300 |
| GAS-60 | Use assembly to emit events | 57 | 2166 |
| GAS-61 | Use assembly to compute hashes to save gas | 9 | 720 |
| GAS-62 | Using assembly to check for zero can save gas | 55 | 330 |
| GAS-63 | Amounts should be checked for 0 before calling a transfer | 7 | - |
Total: 1429 instances over 63 issues with 397370 gas saved.
if (<x> == true) => if (<x>), if (<x> == false) => if (!<x>)
There are 1 instances:
File: packages/contracts/contracts/CdpManager.sol 332: require(redemptionsPaused == false, "CdpManager: Redemptions Paused");
Using unchecked increments can save gas by bypassing the built-in overflow checks. This can save 30-40 gas per iteration. So it is recommended to use unchecked increments when overflow is not possible.
There are 11 instances:
File: packages/contracts/contracts/Governor.sol 46: for (uint256 i = 0; i < users.length(); i++) { 57: for (uint256 i = 0; i < _usrs.length; i++) { 76: for (uint8 i = 0; i < type(uint8).max; i++) { 84: for (uint8 i = 0; i < type(uint8).max; i++) { 98: for (uint8 i = 0; i < type(uint8).max; i++) { 107: for (uint8 i = 0; i < type(uint8).max; i++) { 122: for (uint8 i = 0; i < roleIds.length; i++) { 137: for (uint256 i = 0; i < _sigs.length; ++i) {
File: packages/contracts/contracts/LeverageMacroBase.sol 438: for (uint256 i; i < length; ++i) {
File: packages/contracts/contracts/SortedCdps.sol 432: for (uint256 i = 0; i < _len; ++i) { 449: for (uint i = 0; i < _len; ++i) {
array[index] += amount is cheaper than array[index] = array[index] + amount (or related variants)When updating a value in an array with arithmetic, using array[index] += amount is cheaper than array[index] = array[index] + amount.
This is because you avoid an additonal mload when the array is stored in memory, and an sload when the array is stored in storage.
This can be applied for any arithmetic operation including +=, -=,/=,*=,^=,&=, %=, <<=,>>=, and >>>=.
This optimization can be particularly significant if the pattern occurs during a loop.
Saves 28 gas for a storage array, 38 for a memory array
There are 2 instances:
File: packages/contracts/contracts/EBTCToken.sol 258: _balances[recipient] = _balances[recipient] + amount; 266: _balances[account] = _balances[account] + amount;
Caching of a state variable replaces each Gwarmaccess (100 gas) with a much cheaper stack read. We can avoid unecessary SLOADs by caching storage values that were previously accessed and emitting those cached values.
There are 2 instances:
File: packages/contracts/contracts/CdpManagerStorage.sol /// @audit cache sortedCdps 390: emit CdpUpdated(
File: packages/contracts/contracts/CollSurplusPool.sol /// @audit cache feeRecipientAddress 150: emit SweepTokenSuccess(token, amount, feeRecipientAddress);
If the old value is equal to the new value, not re-storing the value will avoid a Gsreset (2900 gas), potentially at the expense of a Gcoldsload (2100 gas) or a Gwarmaccess (100 gas)
There are 63 instances:
File: packages/contracts/contracts/ActivePool.sol 110: systemCollShares = cachedSystemCollShares; 143: systemCollShares = cachedSystemCollShares; 168: systemCollShares = cachedSystemCollShares; 171: feeRecipientCollShares = cachedFeeRecipientCollShares; 199: systemDebt = cachedSystemDebt; 212: systemDebt = cachedSystemDebt; 246: systemCollShares = cachedSystemCollShares; 359: feeRecipientCollShares = cachedFeeRecipientCollShares; 398: feeRecipientAddress = _feeRecipientAddress;
File: packages/contracts/contracts/BorrowerOperations.sol 1148: feeRecipientAddress = _feeRecipientAddress;
File: packages/contracts/contracts/CdpManagerStorage.sol 118: recoveryModeGracePeriodDuration = _gracePeriod; 271: Cdps[_cdpId].status = closedStatus; 272: Cdps[_cdpId].coll = 0; 273: Cdps[_cdpId].debt = 0; 274: Cdps[_cdpId].liquidatorRewardShares = 0; 276: cdpDebtRedistributionIndex[_cdpId] = 0; 277: cdpStEthFeePerUnitIndex[_cdpId] = 0; 295: totalStakesSnapshot = _totalStakesSnapshot; 298: totalCollateralSnapshot = _totalCollateralSnapshot; 339: cdpDebtRedistributionIndex[_cdpId] = _systemDebtRedistributionIndex; 405: cdpStEthFeePerUnitIndex[_cdpId] = _systemStEthFeePerUnitIndex; 412: totalStakes = _newTotalStakes; 413: Cdps[_cdpId].stake = 0; 423: totalStakes = _newTotalStakes; 479: CdpIds[index] = idToMove; 480: Cdps[idToMove].arrayIndex = index; 541: stEthIndex = _newIndex; 581: systemStEthFeePerUnitIndex = _newPerUnit; 582: systemStEthFeePerUnitIndexError = _newErrorPerUnit; 600: Cdps[_cdpId].coll = _newColl;
File: packages/contracts/contracts/CollSurplusPool.sol 81: balances[_account] = newAmount; 94: balances[_account] = 0; 102: totalSurplusCollShares = cachedTotalSurplusCollShares - claimableColl; 132: totalSurplusCollShares = totalSurplusCollShares + _value;
File: packages/contracts/contracts/Dependencies/Auth.sol 47: authority = newAuthority; 53: owner = newOwner;
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 43: _authority = Authority(newAuthority); 47: _authorityInitialized = true; 59: _authority = Authority(newAuthority); 60: _authorityInitialized = true;
File: packages/contracts/contracts/EBTCToken.sol 255: _balances[sender] = cachedSenderBalances - amount; 258: _balances[recipient] = _balances[recipient] + amount; 265: _totalSupply = _totalSupply + amount; 266: _balances[account] = _balances[account] + amount; 278: _balances[account] = cachedBalance - amount; 281: _totalSupply = _totalSupply - amount;
File: packages/contracts/contracts/Governor.sol 155: roleNames[role] = roleName;
File: packages/contracts/contracts/PriceFeed.sol 377: fallbackCaller = newFallbackCaler; 386: fallbackCaller = newFallbackCaler; 547: status = _status; 554: lastGoodPrice = _currentPrice;
File: packages/contracts/contracts/SortedCdps.sol 384: data.head = _id; 385: data.tail = _id; 390: data.head = _id; 395: data.tail = _id; 404: data.size = data.size + 1; 440: data.head = _lastNext; 445: data.tail = _firstPrev; 453: data.size = data.size - _len; 465: data.head = data.nodes[_id].nextId; 471: data.tail = data.nodes[_id].prevId; 484: data.head = dummyId; 485: data.tail = dummyId;
External calls have an overhead of 100 gas, which can be avoided by not referencing the function using this. Contracts are allowed to override their parents functions and change the visibility from external to public, so make this change if its required in order to call the function internally.
There are 6 instances:
File: packages/contracts/contracts/ActivePool.sol 347: ICdpManagerData(cdpManagerAddress).syncGlobalAccountingAndGracePeriod(); // Calling this increases shares so do it first
File: packages/contracts/contracts/HintHelpers.sol 105: partialRedemptionHintNICR = 0; //reset to 0 as there is no partial redemption in this case
File: packages/contracts/contracts/LeverageMacroBase.sol 73: noFlashloan // Use this to not perform a FL and just `doOperation` 456: require(addy != address(this)); // If it could call this it could fake the forwarded caller
File: packages/contracts/contracts/LeverageMacroReference.sol 33: true // Sweep to caller since this is not supposed to hold funds
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 77: require(msg.sender == address(this)); // Must call this via `execute` to explicitly set the flag
Use uint256(1) and uint256(2) for true/false to avoid a Gwarmaccess (100 gas), and to avoid Gsset (20000 gas) when changing from ‘false’ to ‘true’, after having been ‘true’ in the past. See source.
There are 4 instances:
File: packages/contracts/contracts/CdpManagerStorage.sol 143: bool public redemptionsPaused;
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 14: bool private _authorityInitialized;
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 15: bool public flashLoansPaused;
File: packages/contracts/contracts/LeverageMacroBase.sol 35: bool internal immutable willSweep;
If the data can fit in 32 bytes, the bytes32 data type can be used instead of bytes or strings, as it is more gas efficient and less robust in terms of robustness.
There are 11 instances:
File: packages/contracts/contracts/ActivePool.sol 24: string public constant NAME = "ActivePool";
File: packages/contracts/contracts/BorrowerOperations.sol 29: string public constant NAME = "BorrowerOperations"; 41: string internal constant _VERSION = "1";
File: packages/contracts/contracts/CdpManagerStorage.sol 122: string public constant NAME = "CdpManager";
File: packages/contracts/contracts/CollSurplusPool.sol 19: string public constant NAME = "CollSurplusPool";
File: packages/contracts/contracts/EBTCToken.sol 28: string internal constant _NAME = "EBTC Stablecoin"; 29: string internal constant _SYMBOL = "EBTC"; 30: string internal constant _VERSION = "1";
File: packages/contracts/contracts/HintHelpers.sol 12: string public constant NAME = "HintHelpers";
File: packages/contracts/contracts/PriceFeed.sol 22: string public constant NAME = "PriceFeed";
File: packages/contracts/contracts/SortedCdps.sol 52: string public constant NAME = "SortedCdps";
If not cached, the solidity compiler will always read the length of the array during each iteration. That is, if it is a storage array, this is an extra sload operation (100 additional extra gas for each iteration except for the first) and if it is a memory array, this is an extra mload operation (3 additional gas for each iteration except for the first).
There are 5 instances:
File: packages/contracts/contracts/Governor.sol 46: for (uint256 i = 0; i < users.length(); i++) { 57: for (uint256 i = 0; i < _usrs.length; i++) { 122: for (uint8 i = 0; i < roleIds.length; i++) { 137: for (uint256 i = 0; i < _sigs.length; ++i) {
File: packages/contracts/contracts/LeverageMacroBase.sol 292: uint256 beforeSwapsLength = operation.swapsBefore.length;
The instances below point to the second+ access of a value inside a mapping/array, within a function. Caching a mapping’s value in a local storage or calldata variable when the value is accessed multiple times, saves ~42 gas per access due to not having to recalculate the key’s keccak256 hash (Gkeccak256 - 30 gas) and that calculation’s associated stack operations. Caching an array’s struct avoids recalculating the array offsets into memory/calldata
There are 12 instances:
File: packages/contracts/contracts/CdpManager.sol 152: Cdps[_redeemColFromCdp.cdpId].coll 915: Cdps[_cdpId].coll = _coll;
File: packages/contracts/contracts/CdpManagerStorage.sol 471: uint128 index = Cdps[_cdpId].arrayIndex; 631: uint256 _feeSplitDistributed = Cdps[_cdpId].stake *
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 98: capabilityFlag[target][functionSig] = CapabilityFlag.None; 113: getRolesWithCapability[target][functionSig] |= bytes32(1 << role); 114: enabledFunctionSigsByTarget[target].add(bytes32(functionSig)); 135: capabilityFlag[target][functionSig] != CapabilityFlag.Burned,
File: packages/contracts/contracts/LeverageMacroBase.sol 441: IERC20(swapChecks[i].tokenToCheck).balanceOf(address(this)) >
File: packages/contracts/contracts/LiquidationLibrary.sol 497: Cdps[_cdpId].coll, 796: _liqFlags[vars.i] = true;
File: packages/contracts/contracts/SortedCdps.sol 433: require(contains(_ids[i]), "SortedCdps: List does not contain the id");
The function calls in solidity are expensive. If the same result of the same function calls are to be used several times, the result should be cached to reduce the gas consumption of repeated calls.
There are 35 instances:
File: packages/contracts/contracts/ActivePool.sol 381: IERC20(token).safeTransfer(cachedFeeRecipientAddress, amount);
File: packages/contracts/contracts/CollSurplusPool.sol 148: IERC20(token).safeTransfer(feeRecipientAddress, amount);
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 50: emit AuthorityUpdated(msg.sender, Authority(newAuthority)); 62: emit AuthorityUpdated(address(this), Authority(newAuthority));
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 75: x = decMul(x, x); 79: y = decMul(x, y);
File: packages/contracts/contracts/Governor.sol 59: bool _canCall = doesUserHaveRole(user, role); 84: for (uint8 i = 0; i < type(uint8).max; i++) { 85: if (doesUserHaveRole(user, i)) { 107: for (uint8 i = 0; i < type(uint8).max; i++) {
File: packages/contracts/contracts/LeverageMacroBase.sol 156: IERC3156FlashBorrower(address(this)), 189: _doCheckValueType(checkParams.expectedDebt, cdpInfo.debt); 190: _doCheckValueType(checkParams.expectedCollateral, cdpInfo.coll); 427: IERC20(swapData.tokenForSwap).safeApprove(swapData.addressForApprove, 0);
File: packages/contracts/contracts/LeverageMacroReference.sol 40: stETH.approve(_borrowerOperationsAddress, type(uint256).max); 54: stETH.approve(address(borrowerOperations), type(uint256).max);
File: packages/contracts/contracts/LiquidationLibrary.sol 168: ) = _liquidateCdpInGivenMode(_liqState, _recoveryState); 761: (_checkICRAgainstMCR(vars.ICR) || canLiquidateRecoveryMode(vars.ICR, _TCR)) 783: _TCR = _computeTCRWithGivenSystemValues( 791: _syncAccounting(vars.cdpId); 795: totals = _addLiquidationValuesToTotals(totals, singleLiquidation);
File: packages/contracts/contracts/PriceFeed.sol 126: _changeStatus(Status.usingFallbackChainlinkUntrusted); 169: if (_bothOraclesSimilarPrice(chainlinkResponse, fallbackResponse)) { 202: if (_fallbackIsBroken(fallbackResponse)) { 240: _bothOraclesLiveAndUnbrokenAndSimilarPrice( 246: _changeStatus(Status.chainlinkWorking); 256: if (_chainlinkIsBroken(chainlinkResponse, prevChainlinkResponse)) { 274: if (_chainlinkIsFrozen(chainlinkResponse)) { 292: _changeStatus(Status.usingChainlinkFallbackUntrusted); 297: if (_fallbackIsFrozen(fallbackResponse)) { 310: return _storeFallbackPrice(fallbackResponse); 317: _changeStatus(Status.bothOraclesUntrusted); 340: if (_chainlinkPriceChangeAboveMax(chainlinkResponse, prevChainlinkResponse)) { 347: return _storeChainlinkPrice(chainlinkResponse.answer);
File: packages/contracts/contracts/SortedCdps.sol 704: return _descendList(_NICR, prevId);
When performing multiple operations on a state variable in a function, it is recommended to cache it first. Either multiple reads or multiple writes to a state variable can save gas by caching it on the stack. Caching of a state variable replaces each Gwarmaccess (100 gas) with a much cheaper stack read. Other less obvious fixes/optimizations include having local memory caches of state variable structs, or having local caches of state variable contracts/addresses. Saves 100 gas per instance.
There are 69 instances:
File: packages/contracts/contracts/ActivePool.sol 60: address _authorityAddress = address(AuthNoOwner(cdpManagerAddress).authority()); 295: collateral.balanceOf(address(this)) >= collateral.getPooledEthByShares(systemCollShares), 303: collateral.getPooledEthByShares(DECIMAL_PRECISION) == oldRate, 337: return collateral.balanceOf(address(this));
File: packages/contracts/contracts/BorrowerOperations.sol 364: vars.collShares = cdpManager.getCdpCollShares(_cdpId); 422: sortedCdps.reInsert(_cdpId, newNICR, _upperHint, _lowerHint); 497: cdpManager.notifyStartGracePeriod(newTCR); 583: cdpManager.closeCdp(_cdpId, _borrower, debt, collShares); 893: cdpManager.notifyStartGracePeriod(_vars.newTCR); 1103: ebtcToken.burn(feeRecipientAddress, amount); 1103: ebtcToken.burn(feeRecipientAddress, amount);
File: packages/contracts/contracts/CdpManagerStorage.sol 67: lastGracePeriodStartTimestamp = UNSET_TIMESTAMP; 454: stake = (_coll * totalStakesSnapshot) / totalCollateralSnapshot; 454: stake = (_coll * totalStakesSnapshot) / totalCollateralSnapshot; 483: CdpIds.pop(); 631: uint256 _feeSplitDistributed = Cdps[_cdpId].stake * 774: uint256 _newPerUnit = systemStEthFeePerUnitIndex + _deltaFeePerUnit;
File: packages/contracts/contracts/CollSurplusPool.sol 52: feeRecipientAddress = IActivePool(activePoolAddress).feeRecipientAddress(); 54: address _authorityAddress = address(AuthNoOwner(cdpManagerAddress).authority());
File: packages/contracts/contracts/Dependencies/Auth.sol 45: require(msg.sender == owner || authority.canCall(msg.sender, address(this), msg.sig));
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 41: require(_authority.canCall(msg.sender, address(this), msg.sig)); 57: require(!_authorityInitialized, "Auth: authority already initialized");
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 38: decProd = (prod_xy + (DECIMAL_PRECISION / 2)) / DECIMAL_PRECISION; 65: return DECIMAL_PRECISION;
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 96: capabilityFlag[target][functionSig] = CapabilityFlag.Public; 113: getRolesWithCapability[target][functionSig] |= bytes32(1 << role); 117: targets.add(target); 124: if (enabledFunctionSigsByTarget[target].length() == 0) { 135: capabilityFlag[target][functionSig] != CapabilityFlag.Burned, 152: users.add(user);
File: packages/contracts/contracts/HintHelpers.sol 90: uint256 currentCdpDebt = cdpManager.getSyncedCdpDebt(vars.currentCdpId); 117: vars.currentCdpUser = sortedCdps.getOwnerAddress(vars.currentCdpId); 172: return (sortedCdps.nonExistId(), 0, _inputRandomSeed); 186: uint256 currentNICR = cdpManager.getSyncedNominalICR(_cId);
File: packages/contracts/contracts/LeverageMacroBase.sol 143: initialCdpIndex = sortedCdps.cdpCountOf(address(this)); 199: ICdpManagerData.Cdp memory cdpInfo = cdpManager.Cdps(checkParams.cdpId); 224: ebtcToken.transfer(msg.sender, ebtcBal); 228: stETH.transferShares(msg.sender, collateralBal);
File: packages/contracts/contracts/PriceFeed.sol 283: return lastGoodPrice; 314: if (status == Status.usingChainlinkFallbackUntrusted) { 588: try fallbackCaller.getFallbackResponse() returns ( 634: try ETH_BTC_CL_FEED.latestRoundData() returns ( 650: try STETH_ETH_CL_FEED.latestRoundData() returns ( 722: try ETH_BTC_CL_FEED.getRoundData(_currentRoundEthBtcId - 1) returns ( 738: try STETH_ETH_CL_FEED.getRoundData(_currentRoundStEthEthId - 1) returns (
File: packages/contracts/contracts/SortedCdps.sol 181: bytes32 _currentCdpId = (startNodeId == dummyId ? data.tail : startNodeId); 199: _currentCdpId = data.nodes[_currentCdpId].prevId; 244: bytes32 _currentCdpId = (startNodeId == dummyId ? data.tail : startNodeId); 256: _currentCdpId = data.nodes[_currentCdpId].prevId; 275: (bytes32[] memory _allCdps, , ) = _getCdpsOf(owner, dummyId, 0, _ownedCount); 316: bytes32 _currentCdpId = (startNodeId == dummyId ? data.tail : startNodeId); 327: _currentCdpId = data.nodes[_currentCdpId].prevId; 357: ++nextCdpNonce; 394: data.nodes[data.tail].nextId = _id; 428: _firstPrev != dummyId || _lastNext != dummyId, 443: data.nodes[_lastNext].prevId = _firstPrev; 473: data.nodes[data.tail].nextId = dummyId; 479: data.nodes[data.nodes[_id].nextId].prevId = data.nodes[_id].prevId; 520: bool _exist = _id != dummyId && (data.head == _id || data.tail == _id); 523: _exist = _id != dummyId && (_node.nextId != dummyId && _node.prevId != dummyId); 602: } else if (_nextId == dummyId) { 608: data.nodes[_prevId].nextId == _nextId && 609: cdpManager.getCachedNominalICR(_prevId) >= _NICR && 622: return (dummyId, _startId); 631: nextId = data.nodes[prevId].nextId; 645: return (_startId, dummyId); 654: prevId = data.nodes[nextId].prevId; 690: if (!contains(nextId) || _NICR < cdpManager.getCachedNominalICR(nextId)) { 692: nextId = dummyId;
Mark data types as calldata instead of memory where possible. This makes it so that the data is not automatically loaded into memory. If the data passed into the function does not need to be changed (like updating values in an array), it can be passed in as calldata. The one exception to this is if the argument must later be passed into another function that takes an argument that specifies memory storage.
There are 6 instances:
File: packages/contracts/contracts/CdpManager.sol /// @audit _cdpArray 126: function batchLiquidateCdps(bytes32[] memory _cdpArray) external override {
File: packages/contracts/contracts/Governor.sol /// @audit roleIds 120: function getByteMapFromRoles(uint8[] memory roleIds) public pure returns (bytes32) { /// @audit roleName 154: function setRoleName(uint8 role, string memory roleName) external requiresAuth {
File: packages/contracts/contracts/Interfaces/ISortedCdps.sol /// @audit _ids 16: function batchRemove(bytes32[] memory _ids) external;
File: packages/contracts/contracts/LiquidationLibrary.sol /// @audit _cdpArray 679: function batchLiquidateCdps(bytes32[] memory _cdpArray) external nonReentrantSelfAndBOps {
File: packages/contracts/contracts/SortedCdps.sol /// @audit _ids 419: function batchRemove(bytes32[] memory _ids) external override {
By changing the pattern of assigning value to the structure, gas savings of ~130 per instance are achieved. In addition, this use will provide significant savings in distribution costs.
structure = Structure({parameter1: value1})
can be changed to
structure.parameter1 = value1
There are 8 instances:
File: packages/contracts/contracts/BorrowerOperations.sol 427: MoveTokensParams memory _varMvTokens = MoveTokensParams( msg.sender, vars.collSharesChange, (vars.isCollIncrease ? _stEthBalanceIncrease : 0), vars.isCollIncrease, _debtChange, _isDebtIncrease
File: packages/contracts/contracts/CdpManager.sol 150: CdpDebtAndCollShares memory _oldDebtAndColl = CdpDebtAndCollShares( Cdps[_redeemColFromCdp.cdpId].debt, Cdps[_redeemColFromCdp.cdpId].coll 395: SingleRedemptionInputs memory _redeemColFromCdp = SingleRedemptionInputs( _cId, totals.remainingDebtToRedeem, totals.price, _upperPartialRedemptionHint, _lowerPartialRedemptionHint, _partialRedemptionHintNICR
File: packages/contracts/contracts/CdpManagerStorage.sol 737: return CdpDebtAndCollShares(entireDebt, entireColl);
File: packages/contracts/contracts/LiquidationLibrary.sol 101: LiquidationLocals memory _liqState = LiquidationLocals( _cdpId, _partialAmount, _price, _ICR, _upperPartialHint, _lowerPartialHint, (_recoveryModeAtStart), _TCR, 0, 0, 0, 0, 0 117: LiquidationRecoveryModeLocals memory _rs = LiquidationRecoveryModeLocals( systemDebt, systemColl, 0, 0, 0, _cdpId, _price, _ICR, 0, 0 614: LiquidationLocals memory _liqState = LiquidationLocals( vars.cdpId, 0, _price, vars.ICR, vars.cdpId, vars.cdpId, (false), _TCR, 0, 0, 0, 0, 0 649: LiquidationRecoveryModeLocals memory _recState = LiquidationRecoveryModeLocals( _systemDebt, _systemCollShares, 0, 0, 0, vars.cdpId, _price, vars.ICR, 0, 0
Saves a storage slot for the mapping. Depending on the circumstances and sizes of types, can avoid a Gsset (20000 gas) per mapping combined. Reads and subsequent writes can also be cheaper when a function requires both values and they both fit in the same storage slot. Finally, if both fields are accessed in the same function, can save ~42 gas per access due to not having to recalculate the key keccak256 hash (Gkeccak256 - 30 gas) and that calculations associated stack operations.
There are 6 instances:
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 28: mapping(address => EnumerableSet.Bytes32Set) internal enabledFunctionSigsByTarget; 32: mapping(address => bytes32) public getUserRoles; 34: mapping(address => mapping(bytes4 => CapabilityFlag)) public capabilityFlag; 36: mapping(address => mapping(bytes4 => bytes32)) public getRolesWithCapability;
File: packages/contracts/contracts/EBTCToken.sol 51: mapping(address => uint256) private _balances; 52: mapping(address => mapping(address => uint256)) private _allowances;
By using --via-ir or {"viaIR": true}, the compiler is able to use more advanced multi-function optimizations, for extra gas savings.
There is 1 instance:
File: All Files
The reason for this is that constant variables are evaluated at runtime and their value is included in the bytecode of the contract. This means that any expensive operations performed as part of the constant expression, such as a call to keccak256(), will be executed every time the contract is deployed, even if the result is always the same. This can result in higher gas costs. In contrast, immutable variables are evaluated at compilation time, and their values are included in the bytecode of the contract as constants. This means that any expensive operations performed as part of the immutable expression are only executed once, when the contract is compiled, and the result is reused every time the contract is deployed. This can result in lower gas costs compared to using constant variables.
There are 7 instances:
File: packages/contracts/contracts/BorrowerOperations.sol 32: bytes32 private constant _PERMIT_POSITION_MANAGER_TYPEHASH =
File: packages/contracts/contracts/CdpManagerStorage.sol 21: uint128 public constant UNSET_TIMESTAMP = type(uint128).max; 141: uint256 public constant MIN_REDEMPTION_FEE_FLOOR = (DECIMAL_PRECISION * 5) / 1000; // 0.5%
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 11: bytes32 public constant FLASH_SUCCESS_VALUE = keccak256("ERC3156FlashBorrower.onFlashLoan");
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 7: uint256 public constant MAX_TCR = type(uint256).max;
File: packages/contracts/contracts/LeverageMacroBase.sol 37: bytes32 constant FLASH_LOAN_SUCCESS = keccak256("ERC3156FlashBorrower.onFlashLoan");
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 39: bytes32 constant DIAMOND_STORAGE_POSITION = keccak256("diamond.standard.diamond.storage");
Payable functions cost less gas to execute, because the compiler does not have to add extra checks to ensure that no payment is provided. A constructor can be safely marked as payable, because only the deployer would be able to pass funds, and the project itself would not pass any funds.
There are 19 instances:
File: packages/contracts/contracts/ActivePool.sol 46: constructor(
File: packages/contracts/contracts/BorrowerOperations.sol 107: constructor(
File: packages/contracts/contracts/CdpManager.sol 30: constructor(
File: packages/contracts/contracts/CdpManagerStorage.sol 217: constructor(
File: packages/contracts/contracts/CollSurplusPool.sol 42: constructor(
File: packages/contracts/contracts/Dependencies/Auth.sol 18: constructor(address _owner, Authority _authority) {
File: packages/contracts/contracts/Dependencies/EbtcBase.sol 52: constructor(address _activePoolAddress, address _priceFeedAddress, address _collateralAddress) {
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 20: constructor(address _owner, Authority _authority) Auth(_owner, _authority) {}
File: packages/contracts/contracts/EBTCToken.sol 61: constructor(
File: packages/contracts/contracts/Governor.sol 36: constructor(address _owner) RolesAuthority(_owner, Authority(address(this))) {}
File: packages/contracts/contracts/HintHelpers.sol 27: constructor(
File: packages/contracts/contracts/LeverageMacroBase.sol 51: constructor(
File: packages/contracts/contracts/LeverageMacroDelegateTarget.sol 41: constructor(
File: packages/contracts/contracts/LeverageMacroFactory.sol 21: constructor(
File: packages/contracts/contracts/LeverageMacroReference.sol 17: constructor(
File: packages/contracts/contracts/LiquidationLibrary.sol 14: constructor(
File: packages/contracts/contracts/PriceFeed.sol 57: constructor(
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 44: constructor(address _owner) {
File: packages/contracts/contracts/SortedCdps.sol 88: constructor(uint256 _size, address _cdpManagerAddress, address _borrowerOperationsAddress) {
Custom errors are available from solidity version 0.8.4. Custom errors save ~50 gas each time they’re hit by avoiding having to allocate and store the revert string. Not defining the strings also save deployment gas.
There are 150 instances:
File: packages/contracts/contracts/ActivePool.sol 104: require(cachedSystemCollShares >= _shares, "!ActivePoolBal"); 137: require(cachedSystemCollShares >= _shares, "ActivePool: Insufficient collateral shares"); 162: require(cachedSystemCollShares >= _shares, "ActivePool: Insufficient collateral shares"); 220: require( 228: require( 236: require(msg.sender == cdpManagerAddress, "ActivePool: Caller is not CdpManager"); 267: require(amount > 0, "ActivePool: 0 Amount"); 269: require(amount <= maxFlashLoan(token), "ActivePool: Too much"); 277: require( 294: require( 298: require( 302: require( 318: require(token == address(collateral), "ActivePool: collateral Only"); 319: require(!flashLoansPaused, "ActivePool: Flash Loans Paused"); 350: require( 374: require(token != address(collateral), "ActivePool: Cannot Sweep Collateral"); 377: require(amount <= balance, "ActivePool: Attempt to sweep more than balance"); 393: require( 407: require(_newFee <= MAX_FEE_BPS, "ERC3156FlashLender: _newFee should <= MAX_FEE_BPS");
File: packages/contracts/contracts/BorrowerOperations.sol 145: require(locked == OPEN, "BorrowerOperations: Reentrancy in nonReentrant call"); 146: require( 368: require( 463: require(vars.netStEthBalance > 0, "BorrowerOperations: zero collateral for openCdp()!"); 541: require( 715: require(_deadline >= block.timestamp, "BorrowerOperations: Position manager permit expired"); 734: require( 807: require( 818: require( 826: require(status == 1, "BorrowerOperations: Cdp does not exist or is closed"); 831: require(status == 0, "BorrowerOperations: Cdp is active or has been previously closed"); 835: require(_debtChange > 0, "BorrowerOperations: Debt increase requires non-zero debtChange"); 839: require( 846: require( 911: require( 918: require(_newICR >= CCR, "BorrowerOperations: Operation must leave cdp with ICR >= CCR"); 922: require( 929: require( 936: require(_debt > 0, "BorrowerOperations: Debt must be non-zero"); 940: require( 947: require( 957: require( 970: require( 1083: require(amount > 0, "BorrowerOperations: 0 Amount"); 1085: require(amount <= maxFlashLoan(token), "BorrowerOperations: Too much"); 1091: require( 1115: require(token == address(ebtcToken), "BorrowerOperations: EBTC Only"); 1116: require(!flashLoansPaused, "BorrowerOperations: Flash Loans Paused"); 1141: require( 1155: require(_newFee <= MAX_FEE_BPS, "ERC3156FlashLender: _newFee should <= MAX_FEE_BPS");
File: packages/contracts/contracts/CdpManager.sol 332: require(redemptionsPaused == false, "CdpManager: Redemptions Paused"); 431: require(totals.collSharesDrawn > 0, "CdpManager: Unable to redeem any amount"); 502: require(_toRemoveIds[0] == _start, "CdpManager: batchRemoveSortedCdpIds check start error"); 503: require( 626: require(newBaseRate > 0, "CdpManager: new baseRate is zero!"); // Base rate is always non-zero after redemption 672: require(redemptionFee < _ETHDrawn, "CdpManager: Fee would eat up all returned collateral"); 678: require(decayedBaseRate <= DECIMAL_PRECISION, "CdpManager: baseRate too large!"); // The baseRate can decay to 0 743: require( 747: require( 754: require(_amount > 0, "CdpManager: Amount must be greater than zero"); 758: require(_TCR >= MCR, "CdpManager: Cannot redeem when TCR < MCR"); 762: require( 774: require( 789: require( 793: require( 808: require( 812: require(
File: packages/contracts/contracts/CdpManagerStorage.sol 112: require( 242: require(locked == OPEN, "CdpManager: Reentrancy in nonReentrant call"); 243: require( 261: require( 453: require(totalStakesSnapshot > 0, "CdpManagerStorage: zero totalStakesSnapshot!"); 466: require( 475: require(index <= idxLast, "CdpManagerStorage: CDP indexing overflow!"); 556: require(_newIndex > _prevIndex, "CDPManager: only take fee with bigger new index"); 584: require(activePool.getSystemCollShares() > _feeTaken, "CDPManager: fee split is too big"); 649: require(Cdps[_cdpId].status == Status.active, "CdpManager: Cdp does not exist or is closed"); 653: require( 660: require(
File: packages/contracts/contracts/CollSurplusPool.sol 92: require(claimableColl > 0, "CollSurplusPool: No collateral available to claim"); 99: require(cachedTotalSurplusCollShares >= claimableColl, "!CollSurplusPoolBal"); 113: require( 120: require(msg.sender == cdpManagerAddress, "CollSurplusPool: Caller is not CdpManager"); 124: require(msg.sender == activePoolAddress, "CollSurplusPool: Caller is not Active Pool"); 143: require(token != address(collateral), "CollSurplusPool: Cannot Sweep Collateral"); 146: require(amount <= balance, "CollSurplusPool: Attempt to sweep more than balance");
File: packages/contracts/contracts/Dependencies/Auth.sol 27: require(isAuthorized(msg.sender, msg.sig), "Auth: UNAUTHORIZED");
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 17: require(isAuthorized(msg.sender, msg.sig), "Auth: UNAUTHORIZED"); 56: require(address(_authority) == address(0), "Auth: authority is non-zero"); 57: require(!_authorityInitialized, "Auth: authority already initialized");
File: packages/contracts/contracts/Dependencies/EbtcBase.sol 109: require(feePercentage <= _maxFeePercentage, "Fee exceeded provided maximum");
File: packages/contracts/contracts/Dependencies/ReentrancyGuard.sol 14: require(locked == OPEN, "ReentrancyGuard: Reentrancy in nonReentrant call");
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 90: require( 134: require(
File: packages/contracts/contracts/EBTCToken.sol 144: require(cachedAllowance >= amount, "ERC20: transfer amount exceeds allowance"); 165: require(cachedAllowances >= subtractedValue, "ERC20: decreased allowance below zero"); 208: require(deadline >= block.timestamp, "EBTC: expired deadline"); 219: require(recoveredAddress == owner, "EBTC: invalid signature"); 247: require(sender != address(0), "EBTCToken: zero sender!"); 248: require(recipient != address(0), "EBTCToken: zero recipient!"); 251: require(cachedSenderBalances >= amount, "ERC20: transfer amount exceeds balance"); 263: require(account != address(0), "EBTCToken: mint to zero recipient!"); 271: require(account != address(0), "EBTCToken: burn from zero account!"); 274: require(cachedBalance >= amount, "ERC20: burn amount exceeds balance"); 286: require(owner != address(0), "EBTCToken: zero approve owner!"); 287: require(spender != address(0), "EBTCToken: zero approve spender!"); 296: require( 300: require( 307: require( 315: require( 324: require(msg.sender == cdpManagerAddress, "EBTC: Caller is not CdpManager");
File: packages/contracts/contracts/LeverageMacroBase.sol 40: revert("Must be overridden"); 45: require(owner() == msg.sender, "Must be owner"); 179: require( 191: require( 201: require( 249: require(check.value >= valueToCheck, "!LeverageMacroReference: gte post check"); 251: require(check.value <= valueToCheck, "!LeverageMacroReference: let post check"); 253: require(check.value == valueToCheck, "!LeverageMacroReference: equal post check"); 255: revert("Operator not found"); 352: require(initiator == address(this), "LeverageMacroReference: wrong initiator for flashloan"); 356: require( 362: require( 421: require(success, "Call has failed"); 440: require(
File: packages/contracts/contracts/LiquidationLibrary.sol 56: require(_partialAmount != 0, "LiquidationLibrary: use `liquidate` for 100%"); 82: require( 89: require( 93: require( 477: require( 680: require( 710: require(totals.totalDebtInSequence > 0, "LiquidationLibrary: nothing to liquidate"); 901: require( 909: require(
File: packages/contracts/contracts/PriceFeed.sol 79: require(
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 111: require(msg.sender == owner, "Must be owner"); 179: require(ds.settings.callbackEnabledForCall, "Only Enabled Callbacks"); 187: require(facet != address(0), "Diamond: Function does not exist");
File: packages/contracts/contracts/SortedCdps.sol 352: require(cdpManager.getCdpStatus(_id) == 0, "SortedCdps: new id is NOT nonExistent!"); 365: require(!isFull(), "SortedCdps: List is full"); 367: require(!contains(_id), "SortedCdps: List already contains the node"); 369: require(_id != dummyId, "SortedCdps: Id cannot be zero"); 371: require(_NICR > 0, "SortedCdps: NICR must be positive"); 422: require(_len > 1, "SortedCdps: batchRemove() only apply to multiple cdpIds!"); 427: require( 433: require(contains(_ids[i]), "SortedCdps: List does not contain the id"); 458: require(contains(_id), "SortedCdps: List does not contain the id"); 506: require(contains(_id), "SortedCdps: List does not contain the id"); 508: require(_newNICR > 0, "SortedCdps: NICR must be positive"); 715: require(msg.sender == address(cdpManager), "SortedCdps: Caller is not the CdpManager"); 720: require(
nothing for description
There are 7 instances:
File: packages/contracts/contracts/Governor.sol 46: for (uint256 i = 0; i < users.length(); i++) { 57: for (uint256 i = 0; i < _usrs.length; i++) { 76: for (uint8 i = 0; i < type(uint8).max; i++) { 84: for (uint8 i = 0; i < type(uint8).max; i++) { 98: for (uint8 i = 0; i < type(uint8).max; i++) { 107: for (uint8 i = 0; i < type(uint8).max; i++) { 122: for (uint8 i = 0; i < roleIds.length; i++) {
<x> / 2 is the same as <x> >> 1. While the compiler uses the SHR opcode to accomplish both, the version that uses division incurs an overhead of 20 gas due to JUMPs to and from a compiler utility function that introduces checks which can be avoided by using unchecked {} around the division by two.
There are 3 instances:
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 38: decProd = (prod_xy + (DECIMAL_PRECISION / 2)) / DECIMAL_PRECISION; 77: } else { 81: n = (n - 1) / 2;
This means that if you use uint8 or any variable smaller than 256 bits, EVM has to first convert it uint256 to work on it and the conversion costs extra gas! You may wonder, What were the devs thinking? Why did they create smaller variables then? The answer lies in packing. In solidity, you can pack multiple small variables into one slot, but if you are defining a lone variable and can’t pack it, it’s optimal to use a uint256.
There are 30 instances:
File: packages/contracts/contracts/BorrowerOperations.sol 830: uint status = cdpManager.getCdpStatus(_cdpId);
File: packages/contracts/contracts/CdpManagerStorage.sol 21: uint128 public constant UNSET_TIMESTAMP = type(uint128).max; 22: uint128 public constant MINIMUM_GRACE_PERIOD = 15 minutes; 24: uint128 public lastGracePeriodStartTimestamp = UNSET_TIMESTAMP; // use max to signify 25: uint128 public recoveryModeGracePeriodDuration = MINIMUM_GRACE_PERIOD; 357: uint _pendingDebt, 365: uint prevCollShares = _cdp.coll; 471: uint128 index = Cdps[_cdpId].arrayIndex; 897: uint128 cachedLastGracePeriodStartTimestamp = lastGracePeriodStartTimestamp;
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 14: uint16 public feeBps = 3; // may be subject to future adjustments through protocol governance
File: packages/contracts/contracts/EBTCToken.sol 31: uint8 internal constant _DECIMALS = 18;
File: packages/contracts/contracts/LiquidationLibrary.sol 88: uint128 cachedLastGracePeriodStartTimestamp = lastGracePeriodStartTimestamp; 278: uint _debtToColl = (_totalDebtToBurn * DECIMAL_PRECISION) / _liqState.price; 279: uint _cappedColl = collateral.getPooledEthByShares(_cappedColPortion + _liquidatorReward); 365: uint _debtToColl = (_totalDebtToBurn * DECIMAL_PRECISION) / _recoveryState.price; 366: uint _cappedColl = collateral.getPooledEthByShares(_cappedColPortion + _liquidatorReward); 435: uint _debtToColl = (_partialDebt * DECIMAL_PRECISION) / _partialState.price; 436: uint _cappedColl = collateral.getPooledEthByShares(_partialColl);
File: packages/contracts/contracts/PriceFeed.sol 612: uint8 ethBtcDecimals; 613: uint8 stEthEthDecimals; 700: uint8 ethBtcDecimals; 701: uint8 stEthEthDecimals;
File: packages/contracts/contracts/SortedCdps.sol 182: uint _currentIndex = 0; 183: uint i; 245: uint _ownedCount = 0; 246: uint i = 0; 273: (uint _ownedCount, ) = _cdpCountOf(owner, dummyId, 0); 293: (uint _ownedCount, ) = _cdpCountOf(owner, startNodeId, maxNodes); 311: uint i = 0; 312: uint _cdpRetrieved;
Removing empty blocks help conserve computational resources on the blockchain network, reducing transaction costs and improving overall efficiency.
There are 1 instances:
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 160: receive() external payable {
Emitting an event has an overhead of 375 gas, which will be incurred on every iteration of the loop. It is cheaper to emit only once after the loop has finished.
There are 1 instances:
File: packages/contracts/contracts/SortedCdps.sol 451: emit NodeRemoved(_ids[i]);
The compiler uses opcodes GT and ISZERO for code that uses >, but only requires LT for >=. A similar behaviour applies for >, which uses opcodes LT and ISZERO, but only requires GT for <=, and it can save 3 gas for each.
There are 63 instances:
File: packages/contracts/contracts/ActivePool.sol 267: require(amount > 0, "ActivePool: 0 Amount");
File: packages/contracts/contracts/BorrowerOperations.sol 463: require(vars.netStEthBalance > 0, "BorrowerOperations: zero collateral for openCdp()!"); 476: CCR > MCR (125% vs 110%) 479: Additionally, the new system TCR after the Cdps addition must be >CCR 495: if (newTCR < CCR) { 891: if (_vars.newTCR < CCR) { 913: "BorrowerOperations: An operation that would result in ICR < MCR is not permitted" 931: "BorrowerOperations: An operation that would result in TCR < CCR is not permitted" 1083: require(amount > 0, "BorrowerOperations: 0 Amount");
File: packages/contracts/contracts/CdpManager.sol 389: currentBorrower != address(0) && totals.remainingDebtToRedeem > 0 && _maxIterations > 0 431: require(totals.collSharesDrawn > 0, "CdpManager: Unable to redeem any amount"); 553: 3e30 EBTC dwarfs the value of all wealth in the world ( which is < 1e15 USD). */ 601: return TCR < CCR; 626: require(newBaseRate > 0, "CdpManager: new baseRate is zero!"); // Base rate is always non-zero after redemption 690: uint256 timePassed = block.timestamp > lastRedemptionTimestamp 711: block.timestamp > lastRedemptionTimestamp 758: require(_TCR >= MCR, "CdpManager: Cannot redeem when TCR < MCR");
File: packages/contracts/contracts/CdpManagerStorage.sol 99: if (newTCR < CCR) { 453: require(totalStakesSnapshot > 0, "CdpManagerStorage: zero totalStakesSnapshot!"); 512: if (_newIndex > _oldIndex && totalStakes > 0) { 654: CdpOwnersArrayLength > 1 && sortedCdps.getSize() > 1, 765: if (_newIndex > _oldIndex && totalStakes > 0) { 829: if (pendingDebtRedistributed > 0) { 900: block.timestamp > cachedLastGracePeriodStartTimestamp + recoveryModeGracePeriodDuration;
File: packages/contracts/contracts/CollSurplusPool.sol 92: require(claimableColl > 0, "CollSurplusPool: No collateral available to claim");
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 73: while (n > 1) {
File: packages/contracts/contracts/Governor.sol 46: for (uint256 i = 0; i < users.length(); i++) { 53: if (count > 0) { 76: for (uint8 i = 0; i < type(uint8).max; i++) { 81: if (count > 0) { 84: for (uint8 i = 0; i < type(uint8).max; i++) { 98: for (uint8 i = 0; i < type(uint8).max; i++) { 104: if (count > 0) { 107: for (uint8 i = 0; i < type(uint8).max; i++) { 122: for (uint8 i = 0; i < roleIds.length; i++) { 135: if (_sigs.length > 0) {
File: packages/contracts/contracts/HintHelpers.sol 86: vars.remainingEbtcToRedeem > 0 && 93: if (currentCdpDebt > vars.remainingEbtcToRedeem) { 191: if (currentDiff < diff) {
File: packages/contracts/contracts/LeverageMacroBase.sol 128: if (operation.amountToTransferIn > 0) { 223: if (ebtcBal > 0) { 227: if (collateralBal > 0) { 293: if (beforeSwapsLength > 0) { 307: if (afterSwapsLength > 0) { 385: for (uint256 i; i < swapLength; ) { 438: for (uint256 i; i < length; ++i) {
File: packages/contracts/contracts/LiquidationLibrary.sol 94: block.timestamp > 98: } // Implicit Else Case, Implies ICR < MRC, meaning the CDP is liquidatable 195: if (_outputState.totalSurplusCollShares > 0) { 476: if (_partialState.ICR > LICR) { 525: if (totalDebtToRedistribute > 0) { 710: require(totals.totalDebtInSequence > 0, "LiquidationLibrary: nothing to liquidate"); 713: if (totals.totalCollSurplus > 0) {
File: packages/contracts/contracts/PriceFeed.sol 421: _response.timestampEthBtc > block.timestamp || 423: _response.timestampStEthEth > block.timestamp 457: uint256 percentDeviation = maxPrice > 0 471: if (_response.timestamp == 0 || _response.timestamp > block.timestamp) { 489: _fallbackResponse.timestamp > 0 &&
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 114: for (uint256 i; i < length; ) {
File: packages/contracts/contracts/SortedCdps.sol 202: if (maxNodes > 0 && i >= maxNodes) { 259: if (maxNodes > 0 && i >= maxNodes) { 330: if (maxNodes > 0 && i >= maxNodes) { 460: if (data.size > 1) {
The result of the hash should be stored in an immutable variable, and the variable should be used instead. If the hash is being used as a part of a function selector, the cast to bytes4 should also only be done once.
There are 4 instances:
File: packages/contracts/contracts/BorrowerOperations.sol 33: keccak256(
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 11: bytes32 public constant FLASH_SUCCESS_VALUE = keccak256("ERC3156FlashBorrower.onFlashLoan");
File: packages/contracts/contracts/LeverageMacroBase.sol 37: bytes32 constant FLASH_LOAN_SUCCESS = keccak256("ERC3156FlashBorrower.onFlashLoan");
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 39: bytes32 constant DIAMOND_STORAGE_POSITION = keccak256("diamond.standard.diamond.storage");
There are 19 instances:
File: packages/contracts/contracts/Dependencies/EbtcBase.sol 35: uint256 public constant BORROWING_FEE_FLOOR = 0; // 0.5%
File: packages/contracts/contracts/Governor.sol 46: for (uint256 i = 0; i < users.length(); i++) { 54: uint256 j = 0; 57: for (uint256 i = 0; i < _usrs.length; i++) { 76: for (uint8 i = 0; i < type(uint8).max; i++) { 82: uint256 j = 0; 84: for (uint8 i = 0; i < type(uint8).max; i++) { 98: for (uint8 i = 0; i < type(uint8).max; i++) { 105: uint256 j = 0; 107: for (uint8 i = 0; i < type(uint8).max; i++) { 122: for (uint8 i = 0; i < roleIds.length; i++) { 137: for (uint256 i = 0; i < _sigs.length; ++i) {
File: packages/contracts/contracts/HintHelpers.sol 105: partialRedemptionHintNICR = 0; //reset to 0 as there is no partial redemption in this case
File: packages/contracts/contracts/SortedCdps.sol 182: uint _currentIndex = 0; 245: uint _ownedCount = 0; 246: uint i = 0; 311: uint i = 0; 432: for (uint256 i = 0; i < _len; ++i) { 449: for (uint i = 0; i < _len; ++i) {
If an internal function is only used once, there is no need to modularize it, unless the function calling it would otherwise be too long and complex. Not inlining costs 20 to 40 gas because of two extra JUMP instructions and additional stack operations needed for function calls.
There are 75 instances:
File: packages/contracts/contracts/ActivePool.sol 219: function _requireCallerIsBorrowerOperations() internal view { 235: function _requireCallerIsCdpManager() internal view {
File: packages/contracts/contracts/BorrowerOperations.sol 744: function _getCollSharesChangeFromStEthChange( uint256 _collReceived, uint256 _requestedCollWithdrawal ) internal view returns (uint256 collSharesChange, bool isCollIncrease) { 760: function _processTokenMovesFromAdjustment(MoveTokensParams memory _varMvTokens) internal { 803: function _requireSingularCollChange( uint256 _stEthBalanceIncrease, uint256 _stEthBalanceDecrease ) internal pure { 813: function _requireNonZeroAdjustment( uint256 _stEthBalanceIncrease, uint256 _debtChange, uint256 _stEthBalanceDecrease ) internal pure { 829: function _requireCdpIsNonExistent(bytes32 _cdpId) internal view { 834: function _requireNonZeroDebtChange(uint _debtChange) internal pure { 838: function _requireNotInRecoveryMode(uint256 _tcr) internal view { 845: function _requireNoStEthBalanceDecrease(uint256 _stEthBalanceDecrease) internal pure { 852: function _requireValidAdjustmentInCurrentMode( bool _isRecoveryMode, uint256 _stEthBalanceDecrease, bool _isDebtIncrease, AdjustCdpLocals memory _vars ) internal { 921: function _requireNoDecreaseOfICR(uint256 _newICR, uint256 _oldICR) internal pure { 946: function _requireValidDebtRepayment(uint256 _currentDebt, uint256 _debtRepayment) internal pure { 986: function _getNewNominalICRFromCdpChange( AdjustCdpLocals memory vars, bool _isDebtIncrease ) internal pure returns (uint256) { 1004: function _getNewICRFromCdpChange( uint256 _collShares, uint256 _debt, uint256 _collSharesChange, bool _isCollIncrease, uint256 _debtChange, bool _isDebtIncrease, uint256 _price ) internal view returns (uint256) {
File: packages/contracts/contracts/CdpManager.sol 135: function _redeemCollateralFromCdp( SingleRedemptionInputs memory _redeemColFromCdp ) internal returns (SingleRedemptionValues memory singleRedemption) { 244: function _closeCdpByRedemption( bytes32 _cdpId, uint256 _EBTC, uint256 _collSurplus, uint256 _liquidatorRewardShares, address _borrower ) internal { 272: function _isValidFirstRedemptionHint( bytes32 _firstRedemptionHint, uint256 _price ) internal view returns (bool) { 489: function _getCdpIdsToRemove( bytes32 _start, uint256 _total, bytes32 _end ) internal view returns (bytes32[] memory) { uint256 _cnt = _total; 550: function _addCdpIdToArray(bytes32 _cdpId) internal returns (uint128 index) { /* Max array size is 2**128 - 1, i.e. ~3e30 cdps. No risk of overflow, since cdps have minimum EBTC 595: function _checkPotentialRecoveryMode( uint256 _systemCollShares, uint256 _systemDebt, uint256 _price ) internal view returns (bool) { uint256 TCR = _computeTCRWithGivenSystemValues(_systemCollShares, _systemDebt, _price); 612: function _updateBaseRateFromRedemption( uint256 _ETHDrawn, uint256 _price, uint256 _totalEBTCSupply ) internal returns (uint256) { uint256 decayedBaseRate = _calcDecayedBaseRate(); 655: function _getRedemptionFee(uint256 _ETHDrawn) internal view returns (uint256) { return _calcRedemptionFee(getRedemptionRate(), _ETHDrawn); 737: function _requireEbtcBalanceCoversRedemptionAndWithinSupply( address _redeemer, uint256 _amount, uint256 _totalSupply ) internal view { uint256 callerBalance = ebtcToken.balanceOf(_redeemer); 753: function _requireAmountGreaterThanZero(uint256 _amount) internal pure { require(_amount > 0, "CdpManager: Amount must be greater than zero"); 757: function _requireTCRisNotBelowMCR(uint256 _price, uint256 _TCR) internal view { require(_TCR >= MCR, "CdpManager: Cannot redeem when TCR < MCR"); 761: function _requireValidMaxFeePercentage(uint256 _maxFeePercentage) internal view { require( 977: function _setCdpCollShares(bytes32 _cdpId, uint256 _newColl) internal { Cdps[_cdpId].coll = _newColl; 984: function _setCdpDebt(bytes32 _cdpId, uint256 _newDebt) internal { Cdps[_cdpId].debt = _newDebt;
File: packages/contracts/contracts/CdpManagerStorage.sol 73: function _syncGracePeriod() internal { 260: function _closeCdpWithoutRemovingSortedCdps(bytes32 _cdpId, Status closedStatus) internal { 293: function _updateSystemSnapshotsExcludeCollRemainder(uint256 _collRemainder) internal { 327: function _hasRedistributedDebt(bytes32 _cdpId) internal view returns (bool) { 336: function _updateRedistributedDebtIndex(bytes32 _cdpId) internal { 410: function _removeStake(bytes32 _cdpId) internal { 431: function _updateStakeForCdp(bytes32 _cdpId) internal returns (uint256, uint256) { 441: function _computeNewStake(uint256 _coll) internal view returns (uint256) { 463: function _removeCdp(bytes32 _cdpId, uint256 cdpIdsArrayLength) internal { Status cdpStatus = Cdps[_cdpId].status; 539: function _syncStEthIndex(uint256 _oldIndex, uint256 _newIndex) internal { if (_newIndex != _oldIndex) { 574: function _takeSplitAndUpdateFeePerUnit( uint256 _feeTaken, uint256 _newPerUnit, uint256 _newErrorPerUnit ) internal { uint256 _oldPerUnit = systemStEthFeePerUnitIndex; 592: function _applyAccumulatedFeeSplit( bytes32 _cdpId, uint256 _newColl, uint256 _feeSplitDistributed, uint256 _oldPerUnitCdp, uint256 _systemStEthFeePerUnitIndex ) internal { // apply split fee to given CDP 652: function _requireMoreThanOneCdpInSystem(uint256 CdpOwnersArrayLength) internal view { require( 895: function _recoveryModeGracePeriodPassed() internal view returns (bool) { // we have waited enough
File: packages/contracts/contracts/CollSurplusPool.sol 112: function _requireCallerIsBorrowerOperations() internal view { 119: function _requireCallerIsCdpManager() internal view { 123: function _requireCallerIsActivePool() internal view {
File: packages/contracts/contracts/Dependencies/Auth.sol 32: function isAuthorized(address user, bytes4 functionSig) internal view virtual returns (bool) {
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 30: function isAuthorized(address user, bytes4 functionSig) internal view virtual returns (bool) {
File: packages/contracts/contracts/Dependencies/EbtcBase.sol 75: function _getSystemDebt() internal view returns (uint256 entireSystemDebt) { 79: function _getCachedTCR(uint256 _price) internal view returns (uint256 TCR) { 83: function _getTCRWithSystemDebtAndCollShares( uint256 _price ) internal view returns (uint256 TCR, uint256 _coll, uint256 _debt) { 134: function _checkICRAgainstMCR(uint256 _icr) internal view returns (bool) { 140: function _checkICRAgainstTCR(uint256 _icr, uint _tcr) internal view returns (bool) {
File: packages/contracts/contracts/EBTCToken.sol 262: function _mint(address account, uint256 amount) internal {
File: packages/contracts/contracts/HintHelpers.sol 133: function _calculateCdpStateAfterPartialRedemption( LocalVariables_getRedemptionHints memory vars, uint256 currentCdpDebt, uint256 _price ) internal view returns (uint256, uint256) {
File: packages/contracts/contracts/LeverageMacroBase.sol 398: function _doSwap(SwapOperation memory swapData) internal { 435: function _doSwapChecks(SwapCheck[] memory swapChecks) internal { 450: function _ensureNotSystem(address addy) internal { 460: function _openCdpCallback(bytes memory data) internal { 474: function _closeCdpCallback(bytes memory data) internal { 482: function _adjustCdpCallback(bytes memory data) internal { 498: function excessivelySafeCall( address _target, uint256 _gas, uint256 _value, uint16 _maxCopy, bytes memory _calldata ) internal returns (bool, bytes memory) {
File: packages/contracts/contracts/LiquidationLibrary.sol 135: function _liquidateIndividualCdpSetupCDP( LiquidationLocals memory _liqState, LiquidationRecoveryModeLocals memory _recoveryState ) internal { 450: function _partiallyReduceCdpDebt( bytes32 _cdpId, uint256 _partialDebt, uint256 _partialColl ) internal { 466: function _reInsertPartialLiquidation( LiquidationLocals memory _partialState, uint256 _newNICR, uint256 _oldDebt, uint256 _oldColl ) internal { 642: function _getLiquidationValuesRecoveryMode( uint256 _price, uint256 _systemDebt, uint256 _systemCollShares, LocalVariables_LiquidationSequence memory vars, LiquidationValues memory singleLiquidation ) internal { 733: function _getTotalFromBatchLiquidate_RecoveryMode( uint256 _price, uint256 _systemCollShares, uint256 _systemDebt, bytes32[] memory _cdpArray ) internal returns (LiquidationTotals memory totals) { 807: function _getTotalsFromBatchLiquidate_NormalMode( uint256 _price, uint256 _TCR, bytes32[] memory _cdpArray ) internal returns (LiquidationTotals memory totals) { 862: function _redistributeDebt(uint256 _debt) internal { 896: function _requirePartialLiqDebtSize( uint256 _partialDebt, uint256 _entireDebt, uint256 _price ) internal view { 908: function _requirePartialLiqCollSize(uint256 _entireColl) internal pure {
File: packages/contracts/contracts/PriceFeed.sol 582: function _getCurrentFallbackResponse() internal view returns (FallbackResponse memory fallbackResponse) {
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 134: function _executeOne(Operation calldata op) internal { 174: function _fallback() internal {
File: packages/contracts/contracts/SortedCdps.sol 642: function _ascendList(uint256 _NICR, bytes32 _startId) internal view returns (bytes32, bytes32) {
When you use a modifier in Solidity, Solidity generates code to check the conditions of the modifier and execute the modified function if the conditions are met. This generated code can consume gas, especially if the modifier is used frequently or if the modified function is called multiple times. By inlining a modifier that is used only once and not being inherited, you can eliminate the overhead of the generated code and reduce the gas cost of your contract.
There are 1 instances:
File: packages/contracts/contracts/Dependencies/Auth.sol 26: modifier requiresAuth() virtual {
If a private function is only used once, there is no need to modularize it, unless the function calling it would otherwise be too long and complex.
There are 2 instances:
File: packages/contracts/contracts/LiquidationLibrary.sol 397: function _liquidateCDPPartially( LiquidationLocals memory _partialState ) private returns (uint256, uint256) { 544: function _calculatePartialLiquidationSurplusAndCap( uint256 _ICR, uint256 _price, uint256 _totalDebtToBurn, uint256 _totalColToSend ) private view returns (uint256 toLiquidator, uint256 collSurplus, uint256 debtToRedistribute) {
Using ints/uints smaller than 32 bytes may cost more gas. This is because the EVM operates on 32 bytes at a time, so if an element is smaller than 32 bytes, the EVM must perform more operations to reduce the size of the element from 32 bytes to the desired size.
There are 70 instances:
File: packages/contracts/contracts/BorrowerOperations.sol 34: "PermitPositionManagerApproval(address borrower,address positionManager,uint8 status,uint256 nonce,uint256 deadline)" 711: uint8 v, 1133: return type(uint112).max;
File: packages/contracts/contracts/CdpManager.sol 550: function _addCdpIdToArray(bytes32 _cdpId) internal returns (uint128 index) {
File: packages/contracts/contracts/CdpManagerStorage.sol 21: uint128 public constant UNSET_TIMESTAMP = type(uint128).max; 21: uint128 public constant UNSET_TIMESTAMP = type(uint128).max; 22: uint128 public constant MINIMUM_GRACE_PERIOD = 15 minutes; 24: uint128 public lastGracePeriodStartTimestamp = UNSET_TIMESTAMP; // use max to signify 25: uint128 public recoveryModeGracePeriodDuration = MINIMUM_GRACE_PERIOD; 111: function setGracePeriod(uint128 _gracePeriod) external requiresAuth { 471: uint128 index = Cdps[_cdpId].arrayIndex; 897: uint128 cachedLastGracePeriodStartTimestamp = lastGracePeriodStartTimestamp;
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 14: uint16 public feeBps = 3; // may be subject to future adjustments through protocol governance
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 38: function doesUserHaveRole(address user, uint8 role) public view virtual returns (bool) { 43: uint8 role, 107: uint8 role, 147: function setUserRole(address user, uint8 role, bool enabled) public virtual requiresAuth {
File: packages/contracts/contracts/EBTCToken.sol 31: uint8 internal constant _DECIMALS = 18; 204: uint8 v, 343: function decimals() external pure override returns (uint8) {
File: packages/contracts/contracts/Governor.sol 20: uint8 roleId; 27: uint8[] roles; 30: mapping(uint8 => string) internal roleNames; 32: event RoleNameSet(uint8 indexed role, string indexed name); 43: function getUsersByRole(uint8 role) external view returns (address[] memory usersWithRole) { 73: function getRolesForUser(address user) external view returns (uint8[] memory rolesForUser) { 76: for (uint8 i = 0; i < type(uint8).max; i++) { 76: for (uint8 i = 0; i < type(uint8).max; i++) { 83: rolesForUser = new uint8[](count); 84: for (uint8 i = 0; i < type(uint8).max; i++) { 84: for (uint8 i = 0; i < type(uint8).max; i++) { 96: function getRolesFromByteMap(bytes32 byteMap) public pure returns (uint8[] memory roleIds) { 98: for (uint8 i = 0; i < type(uint8).max; i++) { 98: for (uint8 i = 0; i < type(uint8).max; i++) { 106: roleIds = new uint8[](count); 107: for (uint8 i = 0; i < type(uint8).max; i++) { 107: for (uint8 i = 0; i < type(uint8).max; i++) { 120: function getByteMapFromRoles(uint8[] memory roleIds) public pure returns (bytes32) { 122: for (uint8 i = 0; i < roleIds.length; i++) { 146: function getRoleName(uint8 role) external view returns (string memory roleName) { 154: function setRoleName(uint8 role, string memory roleName) external requiresAuth {
File: packages/contracts/contracts/Interfaces/ICdpManagerData.sol 103: uint128 arrayIndex;
File: packages/contracts/contracts/Interfaces/IPositionManagers.sol 37: uint8 v,
File: packages/contracts/contracts/Interfaces/IPriceFeed.sol 18: uint80 roundEthBtcId; 19: uint80 roundStEthEthId;
File: packages/contracts/contracts/LeverageMacroBase.sol 502: uint16 _maxCopy,
File: packages/contracts/contracts/LiquidationLibrary.sol 88: uint128 cachedLastGracePeriodStartTimestamp = lastGracePeriodStartTimestamp;
File: packages/contracts/contracts/PriceFeed.sol 612: uint8 ethBtcDecimals; 613: uint8 stEthEthDecimals; 615: try ETH_BTC_CL_FEED.decimals() returns (uint8 decimals) { 623: try STETH_ETH_CL_FEED.decimals() returns (uint8 decimals) { 635: uint80 roundId, 640: uint80 /* answeredInRound */ 651: uint80 roundId, 656: uint80 /* answeredInRound */ 688: uint80 _currentRoundEthBtcId, 689: uint80 _currentRoundStEthEthId 700: uint8 ethBtcDecimals; 701: uint8 stEthEthDecimals; 703: try ETH_BTC_CL_FEED.decimals() returns (uint8 decimals) { 711: try STETH_ETH_CL_FEED.decimals() returns (uint8 decimals) { 723: uint80 roundId, 728: uint80 /* answeredInRound */ 739: uint80 roundId, 744: uint80 /* answeredInRound */ 775: function _checkHealthyCLResponse(uint80 _roundId, int256 _answer) internal view returns (bool) { 791: uint8 _ethBtcDecimals, 792: uint8 _stEthEthDecimals
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 102: uint128 value; // How much ETH to send 103: uint128 gas; // How much gas to send
require()/revert() strings longer than 32 bytes cost extra gas
There are 55 instances:
File: packages/contracts/contracts/ActivePool.sol 137: require(cachedSystemCollShares >= _shares, "ActivePool: Insufficient collateral shares"); 162: require(cachedSystemCollShares >= _shares, "ActivePool: Insufficient collateral shares"); 236: require(msg.sender == cdpManagerAddress, "ActivePool: Caller is not CdpManager"); 374: require(token != address(collateral), "ActivePool: Cannot Sweep Collateral"); 377: require(amount <= balance, "ActivePool: Attempt to sweep more than balance"); 407: require(_newFee <= MAX_FEE_BPS, "ERC3156FlashLender: _newFee should <= MAX_FEE_BPS");
File: packages/contracts/contracts/BorrowerOperations.sol 145: require(locked == OPEN, "BorrowerOperations: Reentrancy in nonReentrant call"); 463: require(vars.netStEthBalance > 0, "BorrowerOperations: zero collateral for openCdp()!"); 715: require(_deadline >= block.timestamp, "BorrowerOperations: Position manager permit expired"); 826: require(status == 1, "BorrowerOperations: Cdp does not exist or is closed"); 831: require(status == 0, "BorrowerOperations: Cdp is active or has been previously closed"); 835: require(_debtChange > 0, "BorrowerOperations: Debt increase requires non-zero debtChange"); 918: require(_newICR >= CCR, "BorrowerOperations: Operation must leave cdp with ICR >= CCR"); 936: require(_debt > 0, "BorrowerOperations: Debt must be non-zero"); 1116: require(!flashLoansPaused, "BorrowerOperations: Flash Loans Paused"); 1155: require(_newFee <= MAX_FEE_BPS, "ERC3156FlashLender: _newFee should <= MAX_FEE_BPS");
File: packages/contracts/contracts/CdpManager.sol 431: require(totals.collSharesDrawn > 0, "CdpManager: Unable to redeem any amount"); 502: require(_toRemoveIds[0] == _start, "CdpManager: batchRemoveSortedCdpIds check start error"); 626: require(newBaseRate > 0, "CdpManager: new baseRate is zero!"); // Base rate is always non-zero after redemption 672: require(redemptionFee < _ETHDrawn, "CdpManager: Fee would eat up all returned collateral"); 754: require(_amount > 0, "CdpManager: Amount must be greater than zero"); 758: require(_TCR >= MCR, "CdpManager: Cannot redeem when TCR < MCR");
File: packages/contracts/contracts/CdpManagerStorage.sol 242: require(locked == OPEN, "CdpManager: Reentrancy in nonReentrant call"); 453: require(totalStakesSnapshot > 0, "CdpManagerStorage: zero totalStakesSnapshot!"); 475: require(index <= idxLast, "CdpManagerStorage: CDP indexing overflow!"); 556: require(_newIndex > _prevIndex, "CDPManager: only take fee with bigger new index"); 649: require(Cdps[_cdpId].status == Status.active, "CdpManager: Cdp does not exist or is closed");
File: packages/contracts/contracts/CollSurplusPool.sol 92: require(claimableColl > 0, "CollSurplusPool: No collateral available to claim"); 120: require(msg.sender == cdpManagerAddress, "CollSurplusPool: Caller is not CdpManager"); 124: require(msg.sender == activePoolAddress, "CollSurplusPool: Caller is not Active Pool"); 143: require(token != address(collateral), "CollSurplusPool: Cannot Sweep Collateral"); 146: require(amount <= balance, "CollSurplusPool: Attempt to sweep more than balance");
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 57: require(!_authorityInitialized, "Auth: authority already initialized");
File: packages/contracts/contracts/Dependencies/ReentrancyGuard.sol 14: require(locked == OPEN, "ReentrancyGuard: Reentrancy in nonReentrant call");
File: packages/contracts/contracts/EBTCToken.sol 144: require(cachedAllowance >= amount, "ERC20: transfer amount exceeds allowance"); 165: require(cachedAllowances >= subtractedValue, "ERC20: decreased allowance below zero"); 251: require(cachedSenderBalances >= amount, "ERC20: transfer amount exceeds balance"); 263: require(account != address(0), "EBTCToken: mint to zero recipient!"); 271: require(account != address(0), "EBTCToken: burn from zero account!"); 274: require(cachedBalance >= amount, "ERC20: burn amount exceeds balance");
File: packages/contracts/contracts/LeverageMacroBase.sol 249: require(check.value >= valueToCheck, "!LeverageMacroReference: gte post check"); 251: require(check.value <= valueToCheck, "!LeverageMacroReference: let post check"); 253: require(check.value == valueToCheck, "!LeverageMacroReference: equal post check"); 352: require(initiator == address(this), "LeverageMacroReference: wrong initiator for flashloan");
File: packages/contracts/contracts/LiquidationLibrary.sol 56: require(_partialAmount != 0, "LiquidationLibrary: use `liquidate` for 100%"); 710: require(totals.totalDebtInSequence > 0, "LiquidationLibrary: nothing to liquidate");
File: packages/contracts/contracts/SortedCdps.sol 352: require(cdpManager.getCdpStatus(_id) == 0, "SortedCdps: new id is NOT nonExistent!"); 367: require(!contains(_id), "SortedCdps: List already contains the node"); 371: require(_NICR > 0, "SortedCdps: NICR must be positive"); 422: require(_len > 1, "SortedCdps: batchRemove() only apply to multiple cdpIds!"); 433: require(contains(_ids[i]), "SortedCdps: List does not contain the id"); 458: require(contains(_id), "SortedCdps: List does not contain the id"); 506: require(contains(_id), "SortedCdps: List does not contain the id"); 508: require(_newNICR > 0, "SortedCdps: NICR must be positive"); 715: require(msg.sender == address(cdpManager), "SortedCdps: Caller is not the CdpManager");
Solidity version 0.8.19 introduced a number of gas optimizations, refer to the Solidity 0.8.19 Release Announcement for details.
There are 39 instances:
File: packages/contracts/contracts/ActivePool.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/BorrowerOperations.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/CdpManager.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/CdpManagerStorage.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/CollSurplusPool.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Dependencies/Auth.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Dependencies/EbtcBase.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Dependencies/ReentrancyGuard.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/EBTCToken.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Governor.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/HintHelpers.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IActivePool.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IBorrowerOperations.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/ICdpManager.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/ICdpManagerData.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/ICollSurplusPool.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IEBTCToken.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IERC3156FlashBorrower.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IERC3156FlashLender.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IEbtcBase.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IFallbackCaller.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IPermitNonce.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IPool.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IPositionManagers.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IPriceFeed.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/IRecoveryModeGracePeriod.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/Interfaces/ISortedCdps.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/LeverageMacroBase.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/LeverageMacroDelegateTarget.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/LeverageMacroFactory.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/LeverageMacroReference.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/LiquidationLibrary.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/PriceFeed.sol 3: pragma solidity 0.8.17;
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 2: pragma solidity 0.8.17;
File: packages/contracts/contracts/SortedCdps.sol 3: pragma solidity 0.8.17;
Using a nesting if statement instead of a logical AND (&&) can provide similar short-circuiting behavior whereas double if is slightly more gas efficient.
There are 14 instances:
File: packages/contracts/contracts/BorrowerOperations.sol 393: if (!_isDebtIncrease && _debtChange > 0) {
File: packages/contracts/contracts/CdpManagerStorage.sol 512: if (_newIndex > _oldIndex && totalStakes > 0) { 796: if (_cdpPerUnitIdx != _systemStEthFeePerUnitIndex && _cdpPerUnitIdx > 0) {
File: packages/contracts/contracts/LiquidationLibrary.sol 157: if ( 756: if (vars.cdpId != bytes32(0) && Cdps[vars.cdpId].status == Status.active) { 790: } else if (vars.backToNormalMode && _checkICRAgainstMCR(vars.ICR)) { 819: if (vars.cdpId != bytes32(0) && Cdps[vars.cdpId].status == Status.active) {
File: packages/contracts/contracts/PriceFeed.sol 226: if ( 372: if (
File: packages/contracts/contracts/SortedCdps.sol 202: if (maxNodes > 0 && i >= maxNodes) { 259: if (maxNodes > 0 && i >= maxNodes) { 330: if (maxNodes > 0 && i >= maxNodes) { 621: if (data.head == _startId && _NICR >= cdpManager.getCachedNominalICR(_startId)) { 644: if (data.tail == _startId && _NICR <= cdpManager.getCachedNominalICR(_startId)) {
public/external function names and public member variable names can be optimized to save gas. Below are the interfaces/abstract contracts that can be optimized so that the most frequently-called functions use the least amount of gas possible during method lookup. Method IDs that have two leading zero bytes can save 128 gas each during deployment, and renaming functions to have lower method IDs will save 22 gas per call, per sorted position shifted.
There are 40 instances:
File: packages/contracts/contracts/ActivePool.sol /// @audit (), getSystemCollShares(), getSystemDebt(), getFeeRecipientClaimableCollShares(), transferSystemCollShares(), transferSystemCollSharesAndLiquidatorReward(), allocateSystemCollSharesToFeeRecipient(), increaseSystemDebt(), decreaseSystemDebt(), increaseSystemCollShares(), flashLoan(), flashFee(), maxFlashLoan(), claimFeeRecipientCollShares(), sweepToken(), setFeeRecipientAddress(), setFeeBps(), setFlashLoansPaused(), NAME, borrowerOperationsAddress, cdpManagerAddress, collSurplusPoolAddress, feeRecipientAddress, collateral, 22: contract ActivePool is IActivePool, ERC3156FlashLender, ReentrancyGuard, BaseMath, AuthNoOwner {
File: packages/contracts/contracts/BorrowerOperations.sol /// @audit (), openCdp(), openCdpFor(), addColl(), withdrawColl(), withdrawDebt(), repayDebt(), adjustCdp(), adjustCdpWithColl(), closeCdp(), claimSurplusCollShares(), getPositionManagerApproval(), setPositionManagerApproval(), revokePositionManagerApproval(), renouncePositionManagerApproval(), DOMAIN_SEPARATOR(), domainSeparator(), version(), permitTypeHash(), permitPositionManagerApproval(), flashLoan(), flashFee(), maxFlashLoan(), setFeeRecipientAddress(), setFeeBps(), setFlashLoansPaused(), NAME, cdpManager, collSurplusPool, feeRecipientAddress, ebtcToken, sortedCdps, positionManagers, 21: contract BorrowerOperations is
File: packages/contracts/contracts/CdpManager.sol /// @audit (), getActiveCdpsCount(), getIdFromCdpIdsArray(), liquidate(), partiallyLiquidate(), batchLiquidateCdps(), redeemCollateral(), syncAccounting(), updateStakeAndTotalStakes(), closeCdp(), getSystemDebt(), getCachedTCR(), checkRecoveryMode(), getRedemptionRate(), getRedemptionRateWithDecay(), getRedemptionFeeWithDecay(), getDeploymentStartTime(), checkPotentialRecoveryMode(), setStakingRewardSplit(), setRedemptionFeeFloor(), setMinuteDecayFactor(), setBeta(), setRedemptionsPaused(), getCdpStatus(), getCdpStake(), getCdpDebt(), getCdpCollShares(), getCdpLiquidatorRewardShares(), initializeCdp(), updateCdp(), 16: contract CdpManager is CdpManagerStorage, ICdpManager, Proxy {
File: packages/contracts/contracts/CdpManagerStorage.sol /// @audit notifyStartGracePeriod(), notifyEndGracePeriod(), setGracePeriod(), (), syncGlobalAccounting(), syncGlobalAccountingAndGracePeriod(), calcFeeUponStakingReward(), getAccumulatedFeeSplitApplied(), getCachedNominalICR(), getSyncedNominalICR(), getCachedICR(), getPendingRedistributedDebt(), hasPendingRedistributedDebt(), getSyncedDebtAndCollShares(), getSyncedCdpDebt(), getSyncedCdpCollShares(), getSyncedICR(), getSyncedTCR(), canLiquidateRecoveryMode(), UNSET_TIMESTAMP, MINIMUM_GRACE_PERIOD, lastGracePeriodStartTimestamp, recoveryModeGracePeriodDuration, NAME, borrowerOperationsAddress, ebtcToken, liquidationLibrary, sortedCdps, SECONDS_IN_ONE_MINUTE, MIN_REDEMPTION_FEE_FLOOR, redemptionFeeFloor, redemptionsPaused, minuteDecayFactor, MIN_MINUTE_DECAY_FACTOR, MAX_MINUTE_DECAY_FACTOR, beta, baseRate, stakingRewardSplit, lastRedemptionTimestamp, Cdps, totalStakes, totalStakesSnapshot, totalCollateralSnapshot, systemDebtRedistributionIndex, cdpDebtRedistributionIndex, lastEBTCDebtErrorRedistribution, stEthIndex, systemStEthFeePerUnitIndex, systemStEthFeePerUnitIndexError, cdpStEthFeePerUnitIndex, CdpIds, 19: contract CdpManagerStorage is EbtcBase, ReentrancyGuard, ICdpManagerData, AuthNoOwner {
File: packages/contracts/contracts/CollSurplusPool.sol /// @audit (), getTotalSurplusCollShares(), getSurplusCollShares(), increaseSurplusCollShares(), claimSurplusCollShares(), increaseTotalSurplusCollShares(), sweepToken(), NAME, borrowerOperationsAddress, cdpManagerAddress, activePoolAddress, feeRecipientAddress, collateral, 16: contract CollSurplusPool is ICollSurplusPool, ReentrancyGuard, AuthNoOwner {
File: packages/contracts/contracts/Dependencies/Auth.sol /// @audit setAuthority(), transferOwnership(), owner, authority, 9: abstract contract Auth {
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol /// @audit authority(), authorityInitialized(), setAuthority(), 10: contract AuthNoOwner {
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol /// @audit MAX_BPS, MAX_FEE_BPS, FLASH_SUCCESS_VALUE, feeBps, flashLoansPaused, 8: abstract contract ERC3156FlashLender is IERC3156FlashLender {
File: packages/contracts/contracts/Dependencies/EbtcBase.sol /// @audit (), getSystemCollShares(), LICR, MCR, CCR, LIQUIDATOR_REWARD, MIN_NET_STETH_BALANCE, PERCENT_DIVISOR, BORROWING_FEE_FLOOR, STAKING_REWARD_SPLIT, MAX_REWARD_SPLIT, activePool, priceFeed, collateral, 16: contract EbtcBase is BaseMath, IEbtcBase {
File: packages/contracts/contracts/Dependencies/ReentrancyGuard.sol /// @audit locked, 7: abstract contract ReentrancyGuard {
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol /// @audit (), doesUserHaveRole(), doesRoleHaveCapability(), isPublicCapability(), canCall(), setPublicCapability(), setRoleCapability(), burnCapability(), setUserRole(), getUserRoles, capabilityFlag, getRolesWithCapability, 12: contract RolesAuthority is IRolesAuthority, Auth, Authority {
File: packages/contracts/contracts/EBTCToken.sol /// @audit (), mint(), burn(), burn(), totalSupply(), balanceOf(), transfer(), allowance(), approve(), transferFrom(), increaseAllowance(), decreaseAllowance(), DOMAIN_SEPARATOR(), domainSeparator(), permit(), nonces(), name(), symbol(), decimals(), version(), permitTypeHash(), cdpManagerAddress, borrowerOperationsAddress, 26: contract EBTCToken is IEBTCToken, AuthNoOwner, PermitNonce {
File: packages/contracts/contracts/Governor.sol /// @audit (), getUsersByRole(), getRolesForUser(), getRolesFromByteMap(), getByteMapFromRoles(), getEnabledFunctionsInTarget(), getRoleName(), setRoleName(), 13: contract Governor is RolesAuthority {
File: packages/contracts/contracts/HintHelpers.sol /// @audit (), getRedemptionHints(), getApproxHint(), computeNominalCR(), computeCR(), NAME, sortedCdps, cdpManager, 11: contract HintHelpers is EbtcBase {
File: packages/contracts/contracts/Interfaces/IActivePool.sol /// @audit transferSystemCollShares(), increaseSystemCollShares(), transferSystemCollSharesAndLiquidatorReward(), allocateSystemCollSharesToFeeRecipient(), claimFeeRecipientCollShares(), feeRecipientAddress(), getFeeRecipientClaimableCollShares(), setFeeRecipientAddress(), 7: interface IActivePool is IPool {
File: packages/contracts/contracts/Interfaces/IBorrowerOperations.sol /// @audit openCdp(), openCdpFor(), addColl(), withdrawColl(), withdrawDebt(), repayDebt(), closeCdp(), adjustCdp(), adjustCdpWithColl(), claimSurplusCollShares(), feeRecipientAddress(), 7: interface IBorrowerOperations is IPositionManagers {
File: packages/contracts/contracts/Interfaces/ICdpManager.sol /// @audit getActiveCdpsCount(), getIdFromCdpIdsArray(), liquidate(), partiallyLiquidate(), batchLiquidateCdps(), redeemCollateral(), updateStakeAndTotalStakes(), syncAccounting(), closeCdp(), getRedemptionRate(), getRedemptionRateWithDecay(), getRedemptionFeeWithDecay(), getCdpStatus(), getCdpStake(), getCdpDebt(), getCdpCollShares(), getCdpLiquidatorRewardShares(), initializeCdp(), updateCdp(), getCachedTCR(), checkRecoveryMode(), 9: interface ICdpManager is IEbtcBase, ICdpManagerData {
File: packages/contracts/contracts/Interfaces/ICdpManagerData.sol /// @audit totalStakes(), ebtcToken(), systemStEthFeePerUnitIndex(), systemStEthFeePerUnitIndexError(), stEthIndex(), calcFeeUponStakingReward(), syncGlobalAccounting(), syncGlobalAccountingAndGracePeriod(), getAccumulatedFeeSplitApplied(), getCachedNominalICR(), getCachedICR(), getSyncedCdpDebt(), getSyncedCdpCollShares(), getSyncedICR(), getSyncedTCR(), getSyncedNominalICR(), getPendingRedistributedDebt(), hasPendingRedistributedDebt(), getSyncedDebtAndCollShares(), canLiquidateRecoveryMode(), 13: interface ICdpManagerData is IRecoveryModeGracePeriod {
File: packages/contracts/contracts/Interfaces/ICollSurplusPool.sol /// @audit getTotalSurplusCollShares(), getSurplusCollShares(), increaseSurplusCollShares(), claimSurplusCollShares(), increaseTotalSurplusCollShares(), 5: interface ICollSurplusPool {
File: packages/contracts/contracts/Interfaces/IEBTCToken.sol /// @audit mint(), burn(), 8: interface IEBTCToken is IERC20, IERC2612 {
File: packages/contracts/contracts/Interfaces/IERC3156FlashBorrower.sol /// @audit onFlashLoan(), 5: interface IERC3156FlashBorrower {
File: packages/contracts/contracts/Interfaces/IERC3156FlashLender.sol /// @audit maxFlashLoan(), flashFee(), flashLoan(), 7: interface IERC3156FlashLender {
File: packages/contracts/contracts/Interfaces/IEbtcBase.sol /// @audit priceFeed(), 7: interface IEbtcBase {
File: packages/contracts/contracts/Interfaces/IFallbackCaller.sol /// @audit getFallbackResponse(), fallbackTimeout(), setFallbackTimeout(), 5: interface IFallbackCaller {
File: packages/contracts/contracts/Interfaces/IPermitNonce.sol /// @audit increasePermitNonce(), nonces(), 5: interface IPermitNonce {
File: packages/contracts/contracts/Interfaces/IPool.sol /// @audit getSystemCollShares(), getSystemDebt(), increaseSystemDebt(), decreaseSystemDebt(), 6: interface IPool {
File: packages/contracts/contracts/Interfaces/IPositionManagers.sol /// @audit getPositionManagerApproval(), setPositionManagerApproval(), revokePositionManagerApproval(), renouncePositionManagerApproval(), permitPositionManagerApproval(), version(), permitTypeHash(), domainSeparator(), 5: interface IPositionManagers {
File: packages/contracts/contracts/Interfaces/IPriceFeed.sol /// @audit fetchPrice(), 5: interface IPriceFeed {
File: packages/contracts/contracts/Interfaces/IRecoveryModeGracePeriod.sol /// @audit notifyStartGracePeriod(), notifyEndGracePeriod(), 5: interface IRecoveryModeGracePeriod {
File: packages/contracts/contracts/Interfaces/ISortedCdps.sol /// @audit remove(), batchRemove(), reInsert(), contains(), isFull(), isEmpty(), getSize(), getMaxSize(), getFirst(), getLast(), getNext(), getPrev(), validInsertPosition(), findInsertPosition(), insert(), getOwnerAddress(), nonExistId(), cdpCountOf(), getCdpCountOf(), getCdpsOf(), getAllCdpsOf(), cdpOfOwnerByIndex(), cdpOfOwnerByIdx(), 6: interface ISortedCdps {
File: packages/contracts/contracts/LeverageMacroBase.sol /// @audit Cdps(), 14: interface ICdpCdps { /// @audit owner(), (), doOperation(), sweepToCaller(), sweepToken(), decodeFLData(), onFlashLoan(), borrowerOperations, activePool, cdpManager, ebtcToken, sortedCdps, stETH, 26: contract LeverageMacroBase {
File: packages/contracts/contracts/LeverageMacroDelegateTarget.sol /// @audit owner(), 6: interface IOwnerLike { /// @audit (), owner(), 40: contract LeverageMacroDelegateTarget is LeverageMacroBase {
File: packages/contracts/contracts/LeverageMacroFactory.sol /// @audit (), deployNewMacro(), deployNewMacro(), borrowerOperations, activePool, cdpManager, ebtcToken, stETH, sortedCdps, 11: contract LeverageMacroFactory {
File: packages/contracts/contracts/LeverageMacroReference.sol /// @audit (), owner(), resetApprovals(), 11: contract LeverageMacroReference is LeverageMacroBase {
File: packages/contracts/contracts/LiquidationLibrary.sol /// @audit (), liquidate(), partiallyLiquidate(), batchLiquidateCdps(), 13: contract LiquidationLibrary is CdpManagerStorage {
File: packages/contracts/contracts/PriceFeed.sol /// @audit (), fetchPrice(), setFallbackCaller(), NAME, ETH_BTC_CL_FEED, STETH_ETH_CL_FEED, fallbackCaller, TIMEOUT_ETH_BTC_FEED, TIMEOUT_STETH_ETH_FEED, MAX_PRICE_DEVIATION_FROM_PREVIOUS_ROUND, MAX_PRICE_DIFFERENCE_BETWEEN_ORACLES, lastGoodPrice, status, 21: contract PriceFeed is BaseMath, IPriceFeed, AuthNoOwner {
File: packages/contracts/contracts/SimplifiedDiamondLike.sol /// @audit (), setFallbackHandler(), setAllowAnyCall(), enableCallbackForCall(), execute(), (), (), owner, 25: contract SimplifiedDiamondLike {
File: packages/contracts/contracts/SortedCdps.sol /// @audit (), toCdpId(), getOwnerAddress(), nonExistId(), cdpOfOwnerByIndex(), cdpOfOwnerByIdx(), cdpCountOf(), getCdpCountOf(), getCdpsOf(), getAllCdpsOf(), insert(), remove(), batchRemove(), reInsert(), contains(), isFull(), isEmpty(), getSize(), getMaxSize(), getFirst(), getLast(), getNext(), getPrev(), validInsertPosition(), findInsertPosition(), NAME, borrowerOperationsAddress, cdpManager, maxSize, data, nextCdpNonce, dummyId, 51: contract SortedCdps is ISortedCdps {
Using the += like operator instead of plus-equals saves 113 gas.
There are 8 instances:
File: packages/contracts/contracts/ActivePool.sol 107: cachedSystemCollShares -= _shares; // Updating here avoids an SLOAD 141: cachedSystemCollShares -= _shares; 165: cachedSystemCollShares -= _shares; 356: cachedFeeRecipientCollShares -= _shares;
File: packages/contracts/contracts/CdpManager.sol 697: lastRedemptionTimestamp += _minutesPassedSinceLastRedemption() * SECONDS_IN_ONE_MINUTE;
File: packages/contracts/contracts/Governor.sol 50: count += 1; 78: count += 1; 101: count += 1;
private rather than public for constants, saves gasIf needed, the values can be read from the verified contract source code, or if there are multiple values there can be a single getter function that returns a tuple of the values of all currently-public constants. Saves 3406-3606 gas in deployment gas due to the compiler not having to create non-payable getter functions for deployment calldata, not having to store the bytes of the value outside of where it's used, and not adding another entry to the method ID table
There are 31 instances:
File: packages/contracts/contracts/ActivePool.sol 24: string public constant NAME = "ActivePool";
File: packages/contracts/contracts/BorrowerOperations.sol 29: string public constant NAME = "BorrowerOperations";
File: packages/contracts/contracts/CdpManagerStorage.sol 21: uint128 public constant UNSET_TIMESTAMP = type(uint128).max; 22: uint128 public constant MINIMUM_GRACE_PERIOD = 15 minutes; 122: string public constant NAME = "CdpManager"; 139: uint256 public constant SECONDS_IN_ONE_MINUTE = 60; 141: uint256 public constant MIN_REDEMPTION_FEE_FLOOR = (DECIMAL_PRECISION * 5) / 1000; // 0.5% 149: uint256 public constant MIN_MINUTE_DECAY_FACTOR = 1; // Non-zero 150: uint256 public constant MAX_MINUTE_DECAY_FACTOR = 999999999999999999; // Corresponds to a very fast decay rate, but not too extreme
File: packages/contracts/contracts/CollSurplusPool.sol 19: string public constant NAME = "CollSurplusPool";
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 9: uint256 public constant MAX_BPS = 10_000; 10: uint256 public constant MAX_FEE_BPS = 1_000; // 10% 11: bytes32 public constant FLASH_SUCCESS_VALUE = keccak256("ERC3156FlashBorrower.onFlashLoan");
File: packages/contracts/contracts/Dependencies/EbtcBase.sol 19: uint256 public constant LICR = 1030000000000000000; // 103% 22: uint256 public constant MCR = 1100000000000000000; // 110% 25: uint256 public constant CCR = 1250000000000000000; // 125% 28: uint256 public constant LIQUIDATOR_REWARD = 2e17; 31: uint256 public constant MIN_NET_STETH_BALANCE = 2e18; 33: uint256 public constant PERCENT_DIVISOR = 200; // dividing by 200 yields 0.5% 35: uint256 public constant BORROWING_FEE_FLOOR = 0; // 0.5% 37: uint256 public constant STAKING_REWARD_SPLIT = 5_000; // taking 50% cut from staking reward 39: uint256 public constant MAX_REWARD_SPLIT = 10_000;
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 7: uint256 public constant MAX_TCR = type(uint256).max;
File: packages/contracts/contracts/HintHelpers.sol 12: string public constant NAME = "HintHelpers";
File: packages/contracts/contracts/PriceFeed.sol 22: string public constant NAME = "PriceFeed"; 32: uint256 public constant TIMEOUT_ETH_BTC_FEED = 4800; // 1 hours & 20min: 60 * 80 33: uint256 public constant TIMEOUT_STETH_ETH_FEED = 90000; // 25 hours: 60 * 60 * 25 36: uint256 public constant MAX_PRICE_DEVIATION_FROM_PREVIOUS_ROUND = 5e17; // 50% 42: uint256 public constant MAX_PRICE_DIFFERENCE_BETWEEN_ORACLES = 5e16; // 5%
File: packages/contracts/contracts/SortedCdps.sol 52: string public constant NAME = "SortedCdps"; 80: bytes32 public constant dummyId =
its generally a good practice to limit the visibility of state variables to the minimum necessary level. This means that you should use the private visibility modifier for state variables whenever possible, and avoid using the public modifier unless it is absolutely necessary. Public state variables can be more expensive to read and write than private state variables, since Solidity generates additional getter and setter functions for public variables. By using private state variables, you can reduce the gas cost of your contract and improve its efficiency. Public state variables can be more expensive to read and write than private state variables, since Solidity generates additional getter and setter functions for public variables. By using private state variables, you can reduce the gas cost of your contract and improve its efficiency.
There are 42 instances:
File: packages/contracts/contracts/ActivePool.sol 26: address public immutable borrowerOperationsAddress; 27: address public immutable cdpManagerAddress; 28: address public immutable collSurplusPoolAddress; 29: address public feeRecipientAddress;
File: packages/contracts/contracts/BorrowerOperations.sol 29: string public constant NAME = "BorrowerOperations"; 53: ICdpManager public immutable cdpManager; 57: address public feeRecipientAddress; 65: mapping(address => mapping(address => PositionManagerApproval)) public positionManagers;
File: packages/contracts/contracts/CdpManagerStorage.sol 22: uint128 public constant MINIMUM_GRACE_PERIOD = 15 minutes; 126: address public immutable borrowerOperationsAddress; 173: uint256 public totalStakesSnapshot; 176: uint256 public totalCollateralSnapshot; 190: mapping(bytes32 => uint256) public cdpDebtRedistributionIndex; 196: uint256 public override stEthIndex; 200: uint256 public override systemStEthFeePerUnitIndexError;
File: packages/contracts/contracts/CollSurplusPool.sol 21: address public immutable borrowerOperationsAddress; 22: address public immutable cdpManagerAddress; 23: address public immutable activePoolAddress; 24: address public immutable feeRecipientAddress;
File: packages/contracts/contracts/Dependencies/Auth.sol 16: Authority public authority;
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 7: uint256 public constant MAX_TCR = type(uint256).max;
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 32: mapping(address => bytes32) public getUserRoles; 34: mapping(address => mapping(bytes4 => CapabilityFlag)) public capabilityFlag; 36: mapping(address => mapping(bytes4 => bytes32)) public getRolesWithCapability;
File: packages/contracts/contracts/EBTCToken.sol 55: address public immutable cdpManagerAddress; 56: address public immutable borrowerOperationsAddress;
File: packages/contracts/contracts/HintHelpers.sol 15: ICdpManager public immutable cdpManager;
File: packages/contracts/contracts/LeverageMacroBase.sol 31: ICdpCdps public immutable cdpManager;
File: packages/contracts/contracts/LeverageMacroFactory.sol 14: address public immutable cdpManager;
File: packages/contracts/contracts/PriceFeed.sol 25: AggregatorV3Interface public immutable ETH_BTC_CL_FEED; 26: AggregatorV3Interface public immutable STETH_ETH_CL_FEED; 29: IFallbackCaller public fallbackCaller; // Wrapper contract that calls the fallback system 32: uint256 public constant TIMEOUT_ETH_BTC_FEED = 4800; // 1 hours & 20min: 60 * 80 33: uint256 public constant TIMEOUT_STETH_ETH_FEED = 90000; // 25 hours: 60 * 60 * 25 36: uint256 public constant MAX_PRICE_DEVIATION_FROM_PREVIOUS_ROUND = 5e17; // 50% 42: uint256 public constant MAX_PRICE_DIFFERENCE_BETWEEN_ORACLES = 5e16; // 5% 45: uint256 public lastGoodPrice;
File: packages/contracts/contracts/SortedCdps.sol 54: address public immutable borrowerOperationsAddress; 56: ICdpManager public immutable cdpManager; 58: uint256 public immutable maxSize; 79: uint256 public nextCdpNonce; 80: bytes32 public constant dummyId =
Getters for public state variables are automatically generated so there is no need to code them manually and waste gas.
There are 4 instances:
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 22: function authority() public view returns (Authority) { 26: function authorityInitialized() public view returns (bool) {
File: packages/contracts/contracts/LeverageMacroReference.sol 44: function owner() public override returns (address) {
File: packages/contracts/contracts/SortedCdps.sol 130: function nonExistId() public pure override returns (bytes32) {
Saves deployment costs.
There are 4 instances:
File: packages/contracts/contracts/ActivePool.sol 162: require(cachedSystemCollShares >= _shares, "ActivePool: Insufficient collateral shares");
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 134: require(
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 67: require(msg.sender == owner);
File: packages/contracts/contracts/SortedCdps.sol 506: require(contains(_id), "SortedCdps: List does not contain the id");
Checks that involve constants should come before checks that involve state variables, function calls, and calculations. By doing these checks first, the function is able to revert before wasting a Gcoldsload (2100 gas*) in a function that may ultimately revert in the unhappy case.
There are 38 instances:
File: packages/contracts/contracts/ActivePool.sol /// @audit could be moved to line 101 104: require(cachedSystemCollShares >= _shares, "!ActivePoolBal"); /// @audit could be moved to line 134 137: require(cachedSystemCollShares >= _shares, "ActivePool: Insufficient collateral shares"); /// @audit could be moved to line 158 162: require(cachedSystemCollShares >= _shares, "ActivePool: Insufficient collateral shares"); /// @audit could be moved to line 267 269: require(amount <= maxFlashLoan(token), "ActivePool: Too much"); /// @audit could be moved to line 347 350: require( cachedFeeRecipientCollShares >= _shares, "ActivePool: Insufficient fee recipient coll" /// @audit could be moved to line 372 374: require(token != address(collateral), "ActivePool: Cannot Sweep Collateral"); /// @audit could be moved to line 372 377: require(amount <= balance, "ActivePool: Attempt to sweep more than balance"); /// @audit could be moved to line 391 393: require( _feeRecipientAddress != address(0), "ActivePool: Cannot set fee recipient to zero address" /// @audit could be moved to line 405 407: require(_newFee <= MAX_FEE_BPS, "ERC3156FlashLender: _newFee should <= MAX_FEE_BPS");
File: packages/contracts/contracts/BorrowerOperations.sol /// @audit could be moved to line 338 368: require( _stEthBalanceDecrease <= _cdpStEthBalance, "BorrowerOperations: Cannot withdraw greater stEthBalance than the value in Cdp" /// @audit could be moved to line 446 541: require( vars.netStEthBalance + LIQUIDATOR_REWARD == _stEthBalance, "BorrowerOperations: deposited collateral mismatch!" /// @audit could be moved to line 715 734: require( recoveredAddress != address(0) && recoveredAddress == _borrower, "BorrowerOperations: Invalid signature" /// @audit could be moved to line 1083 1085: require(amount <= maxFlashLoan(token), "BorrowerOperations: Too much");
File: packages/contracts/contracts/CdpManager.sol /// @audit could be moved to line 494 502: require(_toRemoveIds[0] == _start, "CdpManager: batchRemoveSortedCdpIds check start error"); /// @audit could be moved to line 494 503: require( _toRemoveIds[_total - 1] == _end, "CdpManager: batchRemoveSortedCdpIds check end error" /// @audit could be moved to line 671 672: require(redemptionFee < _ETHDrawn, "CdpManager: Fee would eat up all returned collateral"); /// @audit could be moved to line 742 743: require( callerBalance >= _amount, "CdpManager: Requested redemption amount must be <= user's EBTC token balance" /// @audit could be moved to line 742 747: require( callerBalance <= _totalSupply, "CdpManager: redeemer's EBTC balance exceeds total supply!" /// @audit could be moved to line 789 793: require( _redemptionFeeFloor <= DECIMAL_PRECISION, "CDPManager: new redemption fee floor is higher than maximum" /// @audit could be moved to line 808 812: require( _minuteDecayFactor <= MAX_MINUTE_DECAY_FACTOR, "CDPManager: new minute decay factor out of range"
File: packages/contracts/contracts/CdpManagerStorage.sol /// @audit could be moved to line 579 584: require(activePool.getSystemCollShares() > _feeTaken, "CDPManager: fee split is too big");
File: packages/contracts/contracts/CollSurplusPool.sol /// @audit could be moved to line 143 146: require(amount <= balance, "CollSurplusPool: Attempt to sweep more than balance");
File: packages/contracts/contracts/Dependencies/EbtcBase.sol /// @audit could be moved to line 108 109: require(feePercentage <= _maxFeePercentage, "Fee exceeded provided maximum");
File: packages/contracts/contracts/EBTCToken.sol /// @audit could be moved to line 164 165: require(cachedAllowances >= subtractedValue, "ERC20: decreased allowance below zero"); /// @audit could be moved to line 208 219: require(recoveredAddress == owner, "EBTC: invalid signature"); /// @audit could be moved to line 247 248: require(recipient != address(0), "EBTCToken: zero recipient!"); /// @audit could be moved to line 247 251: require(cachedSenderBalances >= amount, "ERC20: transfer amount exceeds balance"); /// @audit could be moved to line 271 274: require(cachedBalance >= amount, "ERC20: burn amount exceeds balance"); /// @audit could be moved to line 286 287: require(spender != address(0), "EBTCToken: zero approve spender!"); /// @audit could be moved to line 296 300: require( _recipient != cdpManagerAddress && _recipient != borrowerOperationsAddress, "EBTC: Cannot transfer tokens directly to the CdpManager or BorrowerOps"
File: packages/contracts/contracts/LeverageMacroBase.sol /// @audit could be moved to line 452 453: require(addy != address(sortedCdps)); /// @audit could be moved to line 452 454: require(addy != address(activePool)); /// @audit could be moved to line 452 455: require(addy != address(cdpManager)); /// @audit could be moved to line 452 456: require(addy != address(this)); // If it could call this it could fake the forwarded caller
File: packages/contracts/contracts/SimplifiedDiamondLike.sol /// @audit could be moved to line 52 56: require(sig != 0x94b24d09);
File: packages/contracts/contracts/SortedCdps.sol /// @audit could be moved to line 365 369: require(_id != dummyId, "SortedCdps: Id cannot be zero"); /// @audit could be moved to line 365 371: require(_NICR > 0, "SortedCdps: NICR must be positive"); /// @audit could be moved to line 504 508: require(_newNICR > 0, "SortedCdps: NICR must be positive");
It’s cheaper to do it once, and store the result to a variable. The examples below are the second+ instance of a given cast of the variable
There are 4 instances:
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 114: enabledFunctionSigsByTarget[target].add(bytes32(functionSig)); 120: getRolesWithCapability[target][functionSig] &= ~bytes32(1 << role); 155: getUserRoles[user] &= ~bytes32(1 << role);
File: packages/contracts/contracts/Governor.sol 108: bool roleEnabled = (uint256(byteMap >> i) & 1) != 0;
There are 3 instances:
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 38: decProd = (prod_xy + (DECIMAL_PRECISION / 2)) / DECIMAL_PRECISION; 76: n = n / 2; 81: n = (n - 1) / 2;
The state variable should be cached in a local variable rather than reading it on every iteration of the for-loop, which will replace each Gwarmaccess (100 gas) with a much cheaper stack read.
There are 21 instances:
File: packages/contracts/contracts/HintHelpers.sol /// @audit cdpManager 70: cdpManager.getSyncedICR(vars.currentCdpId, _price) < MCR /// @audit sortedCdps 72: vars.currentCdpId = sortedCdps.getPrev(vars.currentCdpId); /// @audit sortedCdps 73: vars.currentCdpUser = sortedCdps.getOwnerAddress(vars.currentCdpId); /// @audit cdpManager 90: uint256 currentCdpDebt = cdpManager.getSyncedCdpDebt(vars.currentCdpId); /// @audit sortedCdps 116: vars.currentCdpId = sortedCdps.getPrev(vars.currentCdpId); /// @audit sortedCdps 117: vars.currentCdpUser = sortedCdps.getOwnerAddress(vars.currentCdpId); /// @audit cdpManager 185: bytes32 _cId = cdpManager.getIdFromCdpIdsArray(arrayIndex); /// @audit cdpManager 186: uint256 currentNICR = cdpManager.getSyncedNominalICR(_cId);
File: packages/contracts/contracts/SortedCdps.sol /// @audit dummyId 185: while (_currentCdpId != dummyId) { /// @audit data 199: _currentCdpId = data.nodes[_currentCdpId].prevId; /// @audit dummyId 248: while (_currentCdpId != dummyId) { /// @audit data 256: _currentCdpId = data.nodes[_currentCdpId].prevId; /// @audit dummyId 318: while (_currentCdpId != dummyId) { /// @audit data 327: _currentCdpId = data.nodes[_currentCdpId].prevId; /// @audit data 450: delete data.nodes[_ids[i]]; /// @audit dummyId 629: while (prevId != dummyId && !_validInsertPosition(_NICR, prevId, nextId)) { /// @audit data 630: prevId = data.nodes[prevId].nextId; /// @audit data 631: nextId = data.nodes[prevId].nextId; /// @audit dummyId 652: while (nextId != dummyId && !_validInsertPosition(_NICR, prevId, nextId)) { /// @audit data 653: nextId = data.nodes[nextId].prevId; /// @audit data 654: prevId = data.nodes[nextId].prevId;
Avoids a Gsset (20000 gas) in the constructor, and replaces the first access in each transaction (Gcoldsload - 2100 gas) and each access thereafter (Gwarmacces - 100 gas) with a PUSH32 (3 gas). While strings are not value types, and therefore cannot be immutable/constant if not hard-coded outside of the constructor, the same behavior can be achieved by making the current contract abstract with virtual functions for the string accessors, and having a child contract override the functions with the hard-coded implementation-specific values.
There are 54 instances:
File: packages/contracts/contracts/ActivePool.sol 53: borrowerOperationsAddress = _borrowerOperationsAddress; 54: cdpManagerAddress = _cdpManagerAddress; 55: collateral = ICollateralToken(_collTokenAddress); 56: collSurplusPoolAddress = _collSurplusAddress;
File: packages/contracts/contracts/BorrowerOperations.sol 117: cdpManager = ICdpManager(_cdpManagerAddress); 118: collSurplusPool = ICollSurplusPool(_collSurplusPoolAddress); 119: sortedCdps = ISortedCdps(_sortedCdpsAddress); 120: ebtcToken = IEBTCToken(_ebtcTokenAddress); 131: _HASHED_NAME = hashedName; 132: _HASHED_VERSION = hashedVersion; 133: _CACHED_CHAIN_ID = _chainID(); 134: _CACHED_DOMAIN_SEPARATOR = _buildDomainSeparator(_TYPE_HASH, hashedName, hashedVersion);
File: packages/contracts/contracts/CdpManagerStorage.sol 228: deploymentStartTime = block.timestamp; 229: liquidationLibrary = _liquidationLibraryAddress; 233: borrowerOperationsAddress = _borrowerOperationsAddress; 234: collSurplusPool = ICollSurplusPool(_collSurplusPool); 235: ebtcToken = IEBTCToken(_ebtcToken); 236: sortedCdps = ISortedCdps(_sortedCdps);
File: packages/contracts/contracts/CollSurplusPool.sol 48: borrowerOperationsAddress = _borrowerOperationsAddress; 49: cdpManagerAddress = _cdpManagerAddress; 50: activePoolAddress = _activePoolAddress; 51: collateral = ICollateralToken(_collTokenAddress); 52: feeRecipientAddress = IActivePool(activePoolAddress).feeRecipientAddress();
File: packages/contracts/contracts/Dependencies/EbtcBase.sol 53: activePool = IActivePool(_activePoolAddress); 54: priceFeed = IPriceFeed(_priceFeedAddress); 55: collateral = ICollateralToken(_collateralAddress);
File: packages/contracts/contracts/EBTCToken.sol 68: cdpManagerAddress = _cdpManagerAddress; 69: borrowerOperationsAddress = _borrowerOperationsAddress; 74: _HASHED_NAME = hashedName; 75: _HASHED_VERSION = hashedVersion; 76: _CACHED_CHAIN_ID = _chainID(); 77: _CACHED_DOMAIN_SEPARATOR = _buildDomainSeparator(_TYPE_HASH, hashedName, hashedVersion);
File: packages/contracts/contracts/HintHelpers.sol 34: sortedCdps = ISortedCdps(_sortedCdpsAddress); 35: cdpManager = ICdpManager(_cdpManagerAddress);
File: packages/contracts/contracts/LeverageMacroBase.sol 60: borrowerOperations = IBorrowerOperations(_borrowerOperationsAddress); 61: activePool = IActivePool(_activePool); 62: cdpManager = ICdpCdps(_cdpManager); 63: ebtcToken = IEBTCToken(_ebtc); 64: stETH = ICollateralToken(_coll); 65: sortedCdps = ISortedCdps(_sortedCdps); 67: willSweep = _sweepToCaller;
File: packages/contracts/contracts/LeverageMacroFactory.sol 29: borrowerOperations = _borrowerOperationsAddress; 30: activePool = _activePool; 31: cdpManager = _cdpManager; 32: ebtcToken = _ebtc; 33: stETH = _coll; 34: sortedCdps = _sortedCdps;
File: packages/contracts/contracts/LeverageMacroReference.sol 36: theOwner = _owner;
File: packages/contracts/contracts/PriceFeed.sol 69: ETH_BTC_CL_FEED = AggregatorV3Interface(_ethBtcCLFeed); 70: STETH_ETH_CL_FEED = AggregatorV3Interface(_collEthCLFeed);
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 45: owner = _owner;
File: packages/contracts/contracts/SortedCdps.sol 93: maxSize = _size; 95: cdpManager = ICdpManager(_cdpManagerAddress); 96: borrowerOperationsAddress = _borrowerOperationsAddress;
Avoids a Gsset (20000 gas) at deployment, and replaces the first access in each transaction (Gcoldsload - 2100 gas) and each access thereafter (Gwarmacces - 100 gas) with a PUSH32 (3 gas).
There are 6 instances:
File: packages/contracts/contracts/CdpManagerStorage.sol 142: uint256 public redemptionFeeFloor = MIN_REDEMPTION_FEE_FLOOR; 148: uint256 public minuteDecayFactor = 999037758833783000; 159: uint256 public beta = 2;
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 14: uint16 public feeBps = 3; // may be subject to future adjustments through protocol governance
File: packages/contracts/contracts/Dependencies/ReentrancyGuard.sol 11: uint256 public locked = OPEN;
File: packages/contracts/contracts/Governor.sol 17: bytes32 NO_ROLES = bytes32(0);
Avoids a Gsset (20000 gas) when changing from false to true, after having been true in the past
There are 4 instances:
File: packages/contracts/contracts/CdpManagerStorage.sol 143: bool public redemptionsPaused;
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 14: bool private _authorityInitialized;
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 15: bool public flashLoansPaused;
File: packages/contracts/contracts/LeverageMacroBase.sol 35: bool internal immutable willSweep;
z = (x == y) ? true : false => z = (x == y)
There are 3 instances:
File: packages/contracts/contracts/LiquidationLibrary.sol 100: bool _recoveryModeAtStart = _TCR < CCR ? true : false; 695: vars.recoveryModeAtStart = _TCR < CCR ? true : false; 788: vars.backToNormalMode = _TCR < CCR ? false : true;
There are 53 instances:
File: packages/contracts/contracts/ActivePool.sol 267: require(amount > 0, "ActivePool: 0 Amount");
File: packages/contracts/contracts/BorrowerOperations.sol 393: if (!_isDebtIncrease && _debtChange > 0) { 463: require(vars.netStEthBalance > 0, "BorrowerOperations: zero collateral for openCdp()!"); 835: require(_debtChange > 0, "BorrowerOperations: Debt increase requires non-zero debtChange"); 936: require(_debt > 0, "BorrowerOperations: Debt must be non-zero"); 1083: require(amount > 0, "BorrowerOperations: 0 Amount");
File: packages/contracts/contracts/CdpManager.sol 389: currentBorrower != address(0) && totals.remainingDebtToRedeem > 0 && _maxIterations > 0 389: currentBorrower != address(0) && totals.remainingDebtToRedeem > 0 && _maxIterations > 0 431: require(totals.collSharesDrawn > 0, "CdpManager: Unable to redeem any amount"); 497: while (_cnt > 0 && _id != bytes32(0)) { 626: require(newBaseRate > 0, "CdpManager: new baseRate is zero!"); // Base rate is always non-zero after redemption 754: require(_amount > 0, "CdpManager: Amount must be greater than zero");
File: packages/contracts/contracts/CdpManagerStorage.sol 315: if (_debtIndexDiff > 0) { 362: if (_feeSplitDistributed > 0 || _debtIndexDelta > 0) { 362: if (_feeSplitDistributed > 0 || _debtIndexDelta > 0) { 369: if (_feeSplitDistributed > 0) { 380: if (_debtIndexDelta > 0) { 453: require(totalStakesSnapshot > 0, "CdpManagerStorage: zero totalStakesSnapshot!"); 512: if (_newIndex > _oldIndex && totalStakes > 0) { 765: if (_newIndex > _oldIndex && totalStakes > 0) { 796: if (_cdpPerUnitIdx != _systemStEthFeePerUnitIndex && _cdpPerUnitIdx > 0) { 829: if (pendingDebtRedistributed > 0) { 879: if (_feeTaken > 0) {
File: packages/contracts/contracts/CollSurplusPool.sol 92: require(claimableColl > 0, "CollSurplusPool: No collateral available to claim");
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 93: if (_debt > 0) { 109: if (_debt > 0) {
File: packages/contracts/contracts/Governor.sol 53: if (count > 0) { 81: if (count > 0) { 104: if (count > 0) { 135: if (_sigs.length > 0) {
File: packages/contracts/contracts/HintHelpers.sol 86: vars.remainingEbtcToRedeem > 0 && 87: _maxIterations-- > 0
File: packages/contracts/contracts/LeverageMacroBase.sol 128: if (operation.amountToTransferIn > 0) { 223: if (ebtcBal > 0) { 227: if (collateralBal > 0) { 293: if (beforeSwapsLength > 0) { 307: if (afterSwapsLength > 0) {
File: packages/contracts/contracts/LiquidationLibrary.sol 195: if (_outputState.totalSurplusCollShares > 0) { 261: if (_collSurplus > 0) { 266: if (_debtToRedistribute > 0) { 336: if (_collSurplus > 0) { 342: if (_debtToRedistribute > 0) { 525: if (totalDebtToRedistribute > 0) { 710: require(totals.totalDebtInSequence > 0, "LiquidationLibrary: nothing to liquidate"); 713: if (totals.totalCollSurplus > 0) {
File: packages/contracts/contracts/PriceFeed.sol 457: uint256 percentDeviation = maxPrice > 0 489: _fallbackResponse.timestamp > 0 &&
File: packages/contracts/contracts/SortedCdps.sol 202: if (maxNodes > 0 && i >= maxNodes) { 259: if (maxNodes > 0 && i >= maxNodes) { 274: if (_ownedCount > 0) { 330: if (maxNodes > 0 && i >= maxNodes) { 371: require(_NICR > 0, "SortedCdps: NICR must be positive"); 508: require(_newNICR > 0, "SortedCdps: NICR must be positive");
Consider changing the variable to be an unnamed one, since the variable is never assigned, nor is it returned by name. If the optimizer is not turned on, leaving the code as it is will also waste gas for the stack variable.
There are 9 instances:
File: packages/contracts/contracts/CdpManager.sol /// @audit entireSystemDebt 570: function getSystemDebt() public view returns (uint256 entireSystemDebt) {
File: packages/contracts/contracts/CdpManagerStorage.sol /// @audit pendingEBTCDebtReward 721: ) public view returns (uint256 pendingEBTCDebtReward) {
File: packages/contracts/contracts/Dependencies/EbtcBase.sol /// @audit entireSystemColl 67: function getSystemCollShares() public view returns (uint256 entireSystemColl) { /// @audit entireSystemDebt 75: function _getSystemDebt() internal view returns (uint256 entireSystemDebt) { /// @audit _coll, _debt 85: ) internal view returns (uint256 TCR, uint256 _coll, uint256 _debt) {
File: packages/contracts/contracts/Governor.sol /// @audit roleName 146: function getRoleName(uint8 role) external view returns (string memory roleName) {
File: packages/contracts/contracts/Interfaces/ICdpManagerData.sol /// @audit debt, collShares 261: ) external view returns (uint256 debt, uint256 collShares);
File: packages/contracts/contracts/LiquidationLibrary.sol /// @audit debtToRedistribute 549: ) private view returns (uint256 toLiquidator, uint256 collSurplus, uint256 debtToRedistribute) {
File: packages/contracts/contracts/SimplifiedDiamondLike.sol /// @audit ds 83: function _getStorage() internal pure returns (DiamondLikeStorage storage ds) {
Saves a storage slot. If the variable is assigned a non-zero value, saves Gsset (20000 gas). If it’s assigned a zero value, saves Gsreset (2900 gas). If the variable remains unassigned, there is no gas savings unless the variable is public, in which case the compiler-generated non-payable getter deployment cost is saved. If the state variable is overriding an interface’s public function, mark the variable as constant or immutable so that it does not use a storage slot. Note that there may be cases where a variable superficially appears to be used, but this is only because there are multiple definitions of the variable in different files. In such cases, the variable definition should be moved into a separate file. The instances below are the unused variables.
There are 10 instances:
File: packages/contracts/contracts/ActivePool.sol 24: string public constant NAME = "ActivePool";
File: packages/contracts/contracts/CdpManagerStorage.sol 122: string public constant NAME = "CdpManager";
File: packages/contracts/contracts/CollSurplusPool.sol 19: string public constant NAME = "CollSurplusPool";
File: packages/contracts/contracts/Dependencies/EbtcBase.sol 33: uint256 public constant PERCENT_DIVISOR = 200; // dividing by 200 yields 0.5% 35: uint256 public constant BORROWING_FEE_FLOOR = 0; // 0.5%
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 30: EnumerableSet.Bytes32Set internal enabledFunctionSigsPublic;
File: packages/contracts/contracts/Governor.sol 17: bytes32 NO_ROLES = bytes32(0);
File: packages/contracts/contracts/HintHelpers.sol 12: string public constant NAME = "HintHelpers";
File: packages/contracts/contracts/PriceFeed.sol 22: string public constant NAME = "PriceFeed";
File: packages/contracts/contracts/SortedCdps.sol 52: string public constant NAME = "SortedCdps";
Using a bitmap instead of a bool array or a bool mapping to store boolean states can save gas fees. This is because the bitmap can store 256 boolean values in a single slot instead of 256 slots, which can save gas when writing bool values or when reading multiple bool values from the same slot.
There are 1 instances:
File: packages/contracts/contracts/LiquidationLibrary.sol 751: bool[] memory _liqFlags = new bool[](_cnt);
'it's generally more gas-efficient to use constants instead of type(uintX).max when you need to set the maximum value of an unsigned integer type.'
There are 20 instances:
File: packages/contracts/contracts/BorrowerOperations.sol 1133: return type(uint112).max;
File: packages/contracts/contracts/CdpManager.sol 378: _maxIterations = type(uint256).max;
File: packages/contracts/contracts/CdpManagerStorage.sol 21: uint128 public constant UNSET_TIMESTAMP = type(uint128).max;
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 7: uint256 public constant MAX_TCR = type(uint256).max;
File: packages/contracts/contracts/EBTCToken.sol 143: if (cachedAllowance != type(uint256).max) {
File: packages/contracts/contracts/Governor.sol 76: for (uint8 i = 0; i < type(uint8).max; i++) { 84: for (uint8 i = 0; i < type(uint8).max; i++) { 98: for (uint8 i = 0; i < type(uint8).max; i++) { 107: for (uint8 i = 0; i < type(uint8).max; i++) {
File: packages/contracts/contracts/HintHelpers.sol 79: _maxIterations = type(uint256).max;
File: packages/contracts/contracts/LeverageMacroDelegateTarget.sol 21: ebtcToken.approve(_borrowerOperationsAddress, type(uint256).max); 22: stETH.approve(_borrowerOperationsAddress, type(uint256).max); 23: stETH.approve(_activePool, type(uint256).max);
File: packages/contracts/contracts/LeverageMacroReference.sol 39: ebtcToken.approve(_borrowerOperationsAddress, type(uint256).max); 40: stETH.approve(_borrowerOperationsAddress, type(uint256).max); 41: stETH.approve(_activePool, type(uint256).max); 53: ebtcToken.approve(address(borrowerOperations), type(uint256).max); 54: stETH.approve(address(borrowerOperations), type(uint256).max); 55: stETH.approve(address(activePool), type(uint256).max);
File: packages/contracts/contracts/SortedCdps.sol 90: _size = type(uint256).max;
info struct to 0 saves gasusing the delete keyword to clear a struct or state variable, instead of manually setting its fields to 0 or default values, can save gas. This is because delete efficiently frees up the storage slot, reducing gas costs, particularly in cases involving large or complex data structures.
There are 5 instances:
File: packages/contracts/contracts/CdpManagerStorage.sol 272: Cdps[_cdpId].coll = 0; 273: Cdps[_cdpId].debt = 0; 274: Cdps[_cdpId].liquidatorRewardShares = 0; 413: Cdps[_cdpId].stake = 0;
File: packages/contracts/contracts/HintHelpers.sol 109: vars.remainingEbtcToRedeem = 0;
A do while loop will cost less gas since the condition is not being checked for the first iteration.
There are 15 instances:
File: packages/contracts/contracts/Governor.sol 46: for (uint256 i = 0; i < users.length(); i++) { 57: for (uint256 i = 0; i < _usrs.length; i++) { 76: for (uint8 i = 0; i < type(uint8).max; i++) { 84: for (uint8 i = 0; i < type(uint8).max; i++) { 98: for (uint8 i = 0; i < type(uint8).max; i++) { 107: for (uint8 i = 0; i < type(uint8).max; i++) { 122: for (uint8 i = 0; i < roleIds.length; i++) { 137: for (uint256 i = 0; i < _sigs.length; ++i) {
File: packages/contracts/contracts/LeverageMacroBase.sol 385: for (uint256 i; i < swapLength; ) { 438: for (uint256 i; i < length; ++i) {
File: packages/contracts/contracts/LiquidationLibrary.sol 753: for (vars.i = _start; ; ) { 816: for (vars.i = _start; ; ) {
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 114: for (uint256 i; i < length; ) {
File: packages/contracts/contracts/SortedCdps.sol 432: for (uint256 i = 0; i < _len; ++i) { 449: for (uint i = 0; i < _len; ++i) {
The division cannot overflow, since both the numerator and the denominator are non-negative
There are 35 instances:
File: packages/contracts/contracts/ActivePool.sol 321: return (amount * feeBps) / MAX_BPS;
File: packages/contracts/contracts/BorrowerOperations.sol 1118: return (amount * feeBps) / MAX_BPS;
File: packages/contracts/contracts/CdpManager.sol 146: (singleRedemption.debtToRedeem * DECIMAL_PRECISION) / _redeemColFromCdp.price 621: uint256 redeemedEBTCFraction = (collateral.getPooledEthByShares(_ETHDrawn) * _price) / 624: uint256 newBaseRate = decayedBaseRate + (redeemedEBTCFraction / beta); 671: uint256 redemptionFee = (_redemptionRate * _ETHDrawn) / DECIMAL_PRECISION; 706: return (baseRate * decayFactor) / DECIMAL_PRECISION; 712: ? ((block.timestamp - lastRedemptionTimestamp) / SECONDS_IN_ONE_MINUTE)
File: packages/contracts/contracts/CdpManagerStorage.sol 141: uint256 public constant MIN_REDEMPTION_FEE_FLOOR = (DECIMAL_PRECISION * 5) / 1000; // 0.5% 316: pendingEBTCDebtReward = (cdp.stake * _debtIndexDiff) / DECIMAL_PRECISION; 454: stake = (_coll * totalStakesSnapshot) / totalCollateralSnapshot; 558: uint256 deltaIndexFees = (deltaIndex * stakingRewardSplit) / MAX_REWARD_SPLIT; 564: uint256 _feeTaken = collateral.getSharesByPooledEth(_deltaFeeSplit) / DECIMAL_PRECISION; 567: uint256 _deltaFeePerUnit = _deltaFeeSplitShare / _cachedAllStakes; 639: (_scaledCdpColl - _feeSplitDistributed) / DECIMAL_PRECISION
File: packages/contracts/contracts/Dependencies/EbtcBase.sol 108: uint256 feePercentage = (_fee * DECIMAL_PRECISION) / _amount; 119: return (_debt * _price) / DECIMAL_PRECISION;
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 38: decProd = (prod_xy + (DECIMAL_PRECISION / 2)) / DECIMAL_PRECISION; 38: decProd = (prod_xy + (DECIMAL_PRECISION / 2)) / DECIMAL_PRECISION; 77: } else { 81: n = (n - 1) / 2; 94: return (_collShares * NICR_PRECISION) / _debt; 110: uint256 newCollRatio = (_stEthBalance * _price) / _debt;
File: packages/contracts/contracts/HintHelpers.sol 145: (maxRedeemableEBTC * DECIMAL_PRECISION) / _price
File: packages/contracts/contracts/LiquidationLibrary.sol 278: uint _debtToColl = (_totalDebtToBurn * DECIMAL_PRECISION) / _liqState.price; 365: uint _debtToColl = (_totalDebtToBurn * DECIMAL_PRECISION) / _recoveryState.price; 435: uint _debtToColl = (_partialDebt * DECIMAL_PRECISION) / _partialState.price; 555: _incentiveColl = (_totalDebtToBurn * (_ICR > MCR ? MCR : _ICR)) / _price; 558: _incentiveColl = (_totalDebtToBurn * LICR) / _price; 579: _incentiveColl = (_totalDebtToBurn * (_ICR > MCR ? MCR : _ICR)) / _price; 592: uint256 _debtToRepay = (_incentiveColl * _price) / LICR; 882: uint256 EBTCDebtRewardPerUnitStaked = EBTCDebtNumerator / _totalStakes;
File: packages/contracts/contracts/PriceFeed.sol 458: ? ((maxPrice - minPrice) * EbtcMath.DECIMAL_PRECISION) / maxPrice 534: uint256 percentPriceDifference = ((maxPrice - minPrice) * EbtcMath.DECIMAL_PRECISION) / 801: (_scaledDecimal *
If it can be confirmed that the subtraction operation will not overflow, using an unchecked block can save gas. For example, require(x <= y); z = y - x; can be optimized to require(x <= y); unchecked { z = y - x; }.
There are 22 instances:
File: packages/contracts/contracts/CdpManager.sol /// @audit checked on line 690 691: ? block.timestamp - lastRedemptionTimestamp
File: packages/contracts/contracts/CdpManagerStorage.sol /// @audit checked on line 556 557: uint256 deltaIndex = _newIndex - _prevIndex;
File: packages/contracts/contracts/CollSurplusPool.sol /// @audit checked on line 99 102: totalSurplusCollShares = cachedTotalSurplusCollShares - claimableColl;
File: packages/contracts/contracts/Dependencies/EbtcMath.sol /// @audit checked on line 21 89: return (_a >= _b) ? (_a - _b) : (_b - _a); /// @audit checked on line 25 89: return (_a >= _b) ? (_a - _b) : (_b - _a); /// @audit checked on line 89 89: return (_a >= _b) ? (_a - _b) : (_b - _a); /// @audit checked on line 21 89: return (_a >= _b) ? (_a - _b) : (_b - _a); /// @audit checked on line 25 89: return (_a >= _b) ? (_a - _b) : (_b - _a); /// @audit checked on line 89 89: return (_a >= _b) ? (_a - _b) : (_b - _a);
File: packages/contracts/contracts/EBTCToken.sol /// @audit checked on line 144 146: _approve(sender, msg.sender, cachedAllowance - amount); /// @audit checked on line 165 167: _approve(msg.sender, spender, cachedAllowances - subtractedValue); /// @audit checked on line 251 255: _balances[sender] = cachedSenderBalances - amount; /// @audit checked on line 274 278: _balances[account] = cachedBalance - amount;
File: packages/contracts/contracts/HintHelpers.sol /// @audit checked on line 93 113: vars.remainingEbtcToRedeem = vars.remainingEbtcToRedeem - currentCdpDebt;
File: packages/contracts/contracts/LiquidationLibrary.sol /// @audit checked on line 358 359: ? _recoveryState.entireSystemDebt - _totalDebtToBurn /// @audit checked on line 361 362: ? _recoveryState.entireSystemColl - _totalColToSend /// @audit checked on line 564 567: collSurplus = _totalColToSend - toLiquidator; // Can use unchecked but w/e /// @audit checked on line 594 595: ? _totalDebtToBurn - _debtToRepay // Bad Debt (to be redistributed) is (CdpDebt - Repaid) /// @audit checked on line 564 603: collSurplus = (toLiquidator == _totalColToSend) ? 0 : _totalColToSend - toLiquidator; /// @audit checked on line 602 603: collSurplus = (toLiquidator == _totalColToSend) ? 0 : _totalColToSend - toLiquidator; /// @audit checked on line 603 603: collSurplus = (toLiquidator == _totalColToSend) ? 0 : _totalColToSend - toLiquidator;
File: packages/contracts/contracts/SortedCdps.sol /// @audit checked on line 422 425: bytes32 _lastNext = data.nodes[_ids[_len - 1]].nextId;
internal functions not called by the contract should be removedIf the functions are required by an interface, the contract should inherit from that interface and use the override keyword
There are 1 instances:
File: packages/contracts/contracts/EBTCToken.sol 323: function _requireCallerIsCdpM() internal view {
Using assembly { sstore(state.slot, addr) instead of state = addr can save gas.
There are 26 instances:
File: packages/contracts/contracts/ActivePool.sol 53: borrowerOperationsAddress = _borrowerOperationsAddress; 54: cdpManagerAddress = _cdpManagerAddress; 56: collSurplusPoolAddress = _collSurplusAddress; 57: feeRecipientAddress = _feeRecipientAddress; 398: feeRecipientAddress = _feeRecipientAddress;
File: packages/contracts/contracts/BorrowerOperations.sol 121: feeRecipientAddress = _feeRecipientAddress; 1148: feeRecipientAddress = _feeRecipientAddress;
File: packages/contracts/contracts/CdpManagerStorage.sol 229: liquidationLibrary = _liquidationLibraryAddress; 233: borrowerOperationsAddress = _borrowerOperationsAddress;
File: packages/contracts/contracts/CollSurplusPool.sol 48: borrowerOperationsAddress = _borrowerOperationsAddress; 49: cdpManagerAddress = _cdpManagerAddress; 50: activePoolAddress = _activePoolAddress; 52: feeRecipientAddress = IActivePool(activePoolAddress).feeRecipientAddress();
File: packages/contracts/contracts/Dependencies/Auth.sol 19: owner = _owner; 53: owner = newOwner;
File: packages/contracts/contracts/EBTCToken.sol 68: cdpManagerAddress = _cdpManagerAddress; 69: borrowerOperationsAddress = _borrowerOperationsAddress;
File: packages/contracts/contracts/LeverageMacroFactory.sol 29: borrowerOperations = _borrowerOperationsAddress; 30: activePool = _activePool; 31: cdpManager = _cdpManager; 32: ebtcToken = _ebtc; 33: stETH = _coll; 34: sortedCdps = _sortedCdps;
File: packages/contracts/contracts/LeverageMacroReference.sol 36: theOwner = _owner;
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 45: owner = _owner;
File: packages/contracts/contracts/SortedCdps.sol 96: borrowerOperationsAddress = _borrowerOperationsAddress;
To efficiently emit events, it’s possible to utilize assembly by making use of scratch space in order to save gas. This approach has the advantage of potentially avoiding the costs associated with memory expansion. However, it’s important to note that in order to safely optimize this process, it is preferable to cache and restore the free memory pointer.
There are 57 instances:
File: packages/contracts/contracts/ActivePool.sol 65: emit FeeRecipientAddressChanged(_feeRecipientAddress); 112: emit SystemCollSharesUpdated(cachedSystemCollShares); 113: emit CollSharesTransferred(_account, _shares); 145: emit SystemCollSharesUpdated(cachedSystemCollShares); 146: emit CollSharesTransferred(_account, totalShares); 173: emit SystemCollSharesUpdated(cachedSystemCollShares); 174: emit FeeRecipientClaimableCollSharesIncreased(cachedFeeRecipientCollShares, _shares); 200: emit ActivePoolEBTCDebtUpdated(cachedSystemDebt); 213: emit ActivePoolEBTCDebtUpdated(cachedSystemDebt); 247: emit SystemCollSharesUpdated(cachedSystemCollShares); 360: emit FeeRecipientClaimableCollSharesDecreased(cachedFeeRecipientCollShares, _shares); 399: emit FeeRecipientAddressChanged(_feeRecipientAddress); 421: emit FlashLoansPaused(msg.sender, _paused);
File: packages/contracts/contracts/BorrowerOperations.sol 136: emit FeeRecipientAddressChanged(_feeRecipientAddress); 1149: emit FeeRecipientAddressChanged(_feeRecipientAddress); 1171: emit FlashLoansPaused(msg.sender, _paused);
File: packages/contracts/contracts/CdpManager.sol 55: emit StakingRewardSplitSet(stakingRewardSplit); 630: emit BaseRateUpdated(newBaseRate); 681: emit BaseRateUpdated(decayedBaseRate); 698: emit LastRedemptionTimestampUpdated(block.timestamp); 782: emit StakingRewardSplitSet(_stakingRewardSplit); 801: emit RedemptionFeeFloorSet(_redemptionFeeFloor); 824: emit MinuteDecayFactorSet(_minuteDecayFactor); 836: emit BetaSet(_beta); 848: emit RedemptionsPaused(_paused);
File: packages/contracts/contracts/CdpManagerStorage.sol 50: emit TCRNotified(_tcr); 55: emit GracePeriodStart(); 64: emit TCRNotified(_tcr); 69: emit GracePeriodEnd(); 119: emit GracePeriodDurationSet(_gracePeriod); 300: emit SystemSnapshotsUpdated(_totalStakesSnapshot, _totalCollateralSnapshot); 340: emit CdpDebtRedistributionIndexUpdated(_cdpId, _systemDebtRedistributionIndex); 414: emit TotalStakesUpdated(_newTotalStakes); 425: emit TotalStakesUpdated(_newTotalStakes); 481: emit CdpArrayIndexUpdated(idToMove, index);
File: packages/contracts/contracts/CollSurplusPool.sol 83: emit SurplusCollSharesUpdated(_account, newAmount); 95: emit SurplusCollSharesUpdated(_account, 0); 104: emit CollSharesTransferred(_account, claimableColl);
File: packages/contracts/contracts/Dependencies/Auth.sol 22: emit OwnershipTransferred(msg.sender, _owner); 23: emit AuthorityUpdated(msg.sender, _authority); 49: emit AuthorityUpdated(msg.sender, newAuthority); 55: emit OwnershipTransferred(msg.sender, newOwner);
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 50: emit AuthorityUpdated(msg.sender, Authority(newAuthority)); 62: emit AuthorityUpdated(address(this), Authority(newAuthority));
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 140: emit CapabilityBurned(target, functionSig);
File: packages/contracts/contracts/Governor.sol 157: emit RoleNameSet(role, roleName);
File: packages/contracts/contracts/LeverageMacroFactory.sol 56: emit DeployNewMacro(_owner, addy);
File: packages/contracts/contracts/LiquidationLibrary.sol 891: emit SystemDebtRedistributionIndexUpdated(systemDebtRedistributionIndex);
File: packages/contracts/contracts/PriceFeed.sol 67: emit FallbackCallerChanged(address(0), _fallbackCallerAddress); 378: emit FallbackCallerChanged(oldFallbackCaller, _fallbackCaller); 381: emit UnhealthyFallbackCaller(_fallbackCaller, block.timestamp); 387: emit FallbackCallerChanged(oldFallbackCaller, _fallbackCaller); 548: emit PriceFeedStatusChanged(_status); 555: emit LastGoodPriceUpdated(_currentPrice);
File: packages/contracts/contracts/SortedCdps.sol 405: emit NodeAdded(_id, _NICR); 451: emit NodeRemoved(_ids[i]); 490: emit NodeRemoved(_id);
If the arguments to the encode call can fit into the scratch space (two words or fewer), then it’s more efficient to use assembly to generate the hash (80 gas): keccak256(abi.encodePacked(x, y)) -> assembly {mstore(0x00, a); mstore(0x20, b); let hash := keccak256(0x00, 0x40); }
There are 9 instances:
File: packages/contracts/contracts/BorrowerOperations.sol 33: keccak256( "PermitPositionManagerApproval(address borrower,address positionManager,uint8 status,uint256 nonce,uint256 deadline)" 128: bytes32 hashedName = keccak256(bytes(NAME)); 129: bytes32 hashedVersion = keccak256(bytes(_VERSION));
File: packages/contracts/contracts/Dependencies/ERC3156FlashLender.sol 11: bytes32 public constant FLASH_SUCCESS_VALUE = keccak256("ERC3156FlashBorrower.onFlashLoan");
File: packages/contracts/contracts/EBTCToken.sol 71: bytes32 hashedName = keccak256(bytes(_NAME)); 72: bytes32 hashedVersion = keccak256(bytes(_VERSION));
File: packages/contracts/contracts/HintHelpers.sol 182: latestRandomSeed = uint256(keccak256(abi.encodePacked(latestRandomSeed)));
File: packages/contracts/contracts/LeverageMacroBase.sol 37: bytes32 constant FLASH_LOAN_SUCCESS = keccak256("ERC3156FlashBorrower.onFlashLoan");
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 39: bytes32 constant DIAMOND_STORAGE_POSITION = keccak256("diamond.standard.diamond.storage");
Using assembly to check for zero can save gas by allowing more direct access to the evm and reducing some of the overhead associated with high-level operations in solidity.
There are 55 instances:
File: packages/contracts/contracts/ActivePool.sol 61: if (_authorityAddress != address(0)) { 394: _feeRecipientAddress != address(0),
File: packages/contracts/contracts/BorrowerOperations.sol 124: if (_authorityAddress != address(0)) { 735: recoveredAddress != address(0) && recoveredAddress == _borrower, 748: if (_collReceived != 0) { 808: _stEthBalanceIncrease == 0 || _stEthBalanceDecrease == 0, 808: _stEthBalanceIncrease == 0 || _stEthBalanceDecrease == 0, 819: _stEthBalanceIncrease != 0 || _stEthBalanceDecrease != 0 || _debtChange != 0, 831: require(status == 0, "BorrowerOperations: Cdp is active or has been previously closed"); 847: _stEthBalanceDecrease == 0, 1142: _feeRecipientAddress != address(0),
File: packages/contracts/contracts/CdpManager.sol 159: if (newDebt == 0) { 369: while (currentBorrower != address(0) && getSyncedICR(_cId, totals.price) < MCR) { 377: if (_maxIterations == 0) {
File: packages/contracts/contracts/CdpManagerStorage.sol 443: if (totalCollateralSnapshot == 0) {
File: packages/contracts/contracts/CollSurplusPool.sol 55: if (_authorityAddress != address(0)) {
File: packages/contracts/contracts/Dependencies/AuthNoOwner.sol 35: return (address(auth) != address(0) && auth.canCall(user, address(this), functionSig)); 56: require(address(_authority) == address(0), "Auth: authority is non-zero");
File: packages/contracts/contracts/Dependencies/EbtcMath.sol 64: if (_minutes == 0) { 74: if (n % 2 == 0) {
File: packages/contracts/contracts/Dependencies/RolesAuthority.sol 39: return (uint256(getUserRoles[user]) >> role) & 1 != 0; 47: return (uint256(getRolesWithCapability[target][functionSig]) >> role) & 1 != 0; 124: if (enabledFunctionSigsByTarget[target].length() == 0) {
File: packages/contracts/contracts/EBTCToken.sol 247: require(sender != address(0), "EBTCToken: zero sender!"); 248: require(recipient != address(0), "EBTCToken: zero recipient!"); 263: require(account != address(0), "EBTCToken: mint to zero recipient!"); 271: require(account != address(0), "EBTCToken: burn from zero account!"); 286: require(owner != address(0), "EBTCToken: zero approve owner!"); 287: require(spender != address(0), "EBTCToken: zero approve spender!"); 297: _recipient != address(0) && _recipient != address(this),
File: packages/contracts/contracts/Governor.sol 99: bool roleEnabled = (uint256(byteMap >> i) & 1) != 0; 108: bool roleEnabled = (uint256(byteMap >> i) & 1) != 0;
File: packages/contracts/contracts/HintHelpers.sol 69: vars.currentCdpUser != address(0) && 78: if (_maxIterations == 0) { 171: if (arrayLength == 0) {
File: packages/contracts/contracts/LiquidationLibrary.sol 56: require(_partialAmount != 0, "LiquidationLibrary: use `liquidate` for 100%"); 144: if (_liqState.partialAmount == 0) { 158: liquidationValues.totalCollToSendToLiquidator == 0 && 159: liquidationValues.debtToBurn == 0 417: if (newColl == 0) { 681: _cdpArray.length != 0, 863: if (_debt == 0) {
File: packages/contracts/contracts/PriceFeed.sol 224: if (address(fallbackCaller) == address(0)) { 471: if (_response.timestamp == 0 || _response.timestamp > block.timestamp) { 475: if (_response.answer == 0) { 532: if (minPrice == 0) return false; 587: if (address(fallbackCaller) != address(0)) { 695: if (_currentRoundEthBtcId == 0 || _currentRoundStEthEthId == 0) { 695: if (_currentRoundEthBtcId == 0 || _currentRoundStEthEthId == 0) { 777: if (_roundId == 0) return false;
File: packages/contracts/contracts/SimplifiedDiamondLike.sol 187: require(facet != address(0), "Diamond: Function does not exist");
File: packages/contracts/contracts/SortedCdps.sol 89: if (_size == 0) { 305: if (maxArraySize == 0) { 352: require(cdpManager.getCdpStatus(_id) == 0, "SortedCdps: new id is NOT nonExistent!"); 537: return data.size == 0;
It is generally a good practice to check for zero values before making any transfers in smart contract functions. This can help to avoid unnecessary external calls and can save gas costs. Checking for zero values is especially important when transferring tokens or ether, as sending these assets to an address with a zero value will result in the loss of those assets.
There are 7 instances:
File: packages/contracts/contracts/ActivePool.sol 283: collateral.transferFrom(address(receiver), address(this), amountWithFee); 286: collateral.transfer(feeRecipientAddress, fee); 381: IERC20(token).safeTransfer(cachedFeeRecipientAddress, amount);
File: packages/contracts/contracts/BorrowerOperations.sol 785: collateral.transferFrom(msg.sender, address(activePool), _stEthBalance); 1100: ebtcToken.transferFrom(address(receiver), feeRecipientAddress, fee + amount);
File: packages/contracts/contracts/CollSurplusPool.sol 148: IERC20(token).safeTransfer(feeRecipientAddress, amount);
File: packages/contracts/contracts/LeverageMacroBase.sol 237: IERC20(token).safeTransfer(msg.sender, amount);
#0 - c4-pre-sort
2023-11-17T14:44:17Z
bytes032 marked the issue as sufficient quality report
#1 - c4-judge
2023-11-28T03:02:02Z
jhsagd76 marked the issue as grade-c
#2 - zabihullah-azadzoi
2023-12-06T13:36:32Z
Hi @jhsagd76 I would like to draw your attention once again to review the findings submitted in this report, all of findings included in this report are proven to have low or high impact on gas saving and were widely accepted in the previous contests and reports.
I would love to provide more context and clarification regarding the impact of each or any finding if needed. Thank you.
#3 - zabihullah-azadzoi
2023-12-06T15:03:22Z
@jhsagd76 This is not a bot-generated report, and I think high number of finding is not an indication of being so. I dedicated enough of my time to find as much possible impact full instances. and regarding overlapping with 4naly3er report, since most of the findings and instances found by 4naly3er are always invalid, thus i didn't take it into consideration that much, but even if there is any overlap it's in less than 4 of 5 findings, and rejecting the entire report for that reason won't be fair.(according to me) Thank you.
#4 - jhsagd76
2023-12-06T19:24:19Z
2 * 29 - 3 * 12 + 1 * 21 + 0 * 1
43
#5 - c4-judge
2023-12-06T20:58:27Z
jhsagd76 marked the issue as grade-a