GAS-1: <X> * 2 costs more gas then <X> << 1
Description
Using bitwize operator instead of '*' or '/' saves gas.
Affected file
- LSP2Utils.sol (Line: 242)
GAS-2: <X> <= <Y> costs more gas than <X> < <Y> + 1
Description
In Solididy, the opcode 'less or equal' doesn't exist. So the EVM will translate this by two distinct operation, first the inferior, and then the equal which cost more gas then a strict less.
Affected file
- LSP0ERC725AccountCore.sol (Line: 474, 506)
- LSP2Utils.sol (Line: 36, 335)
- LSP5Utils.sol (Line: 190)
- LSP6ExecuteModule.sol (Line: 353)
- LSP6Utils.sol (Line: 97, 126)
GAS-3: Caching global variables is more expensive than using the actual variable
Description
It’s cheaper to use global variable as compared to caching.
Affected file
- LSP14Ownable2Step.sol (Line: 151)
- LSP7DigitalAssetCore.sol (Line: 133, 304, 352, 415)
- LSP8CompatibleERC721.sol (Line: 233)
- LSP8CompatibleERC721InitAbstract.sol (Line: 233)
- LSP8IdentifiableDigitalAssetCore.sol (Line: 198, 327, 361, 414)
GAS-4: Empty blocks should be removed or emit something
Description
The code should be refactored such that they no longer exist, or the block should do something useful, such as emitting an event or reverting.
Affected file
- LSP7CompatibleERC20.sol (Line: 32)
- LSP7CompatibleERC20Mintable.sol (Line: 7)
- LSP7DigitalAssetCore.sol (Line: 442)
- LSP7Mintable.sol (Line: 24)
- LSP8CompatibleERC721.sol (Line: 67)
- LSP8CompatibleERC721Mintable.sol (Line: 7)
- LSP8IdentifiableDigitalAsset.sol (Line: 36)
- LSP8IdentifiableDigitalAssetCore.sol (Line: 444)
- LSP8Mintable.sol (Line: 23)
GAS-5: Internal functions not called by the contract should be removed to save deployment gas
Description
If the functions are required by an interface, the contract should inherit from that interface and use the override keyword.
Affected file
- LSP0ERC725AccountInitAbstract.sol (Line: 59)
- LSP17Extendable.sol (Line: 44, 86)
- LSP17Extension.sol (Line: 32, 44, 54)
- LSP20CallVerification.sol (Line: 23, 49)
- LSP6ExecuteModule.sol (Line: 61)
- LSP6KeyManagerCore.sol (Line: 518)
- LSP6KeyManagerInitAbstract.sol (Line: 20)
- LSP6OwnershipModule.sol (Line: 14)
- LSP6SetDataModule.sol (Line: 62, 116)
- LSP7CappedSupplyInitAbstract.sol (Line: 21)
- LSP7DigitalAssetCore.sol (Line: 294, 338)
- LSP8CappedSupplyInitAbstract.sol (Line: 23)
- LSP8IdentifiableDigitalAssetCore.sol (Line: 313, 359)
GAS-6: Internal functions only called once can be inlined to save gas
Description
Not inlining costs 20 to 40 gas because of two extra JUMP instructions and additional stack operations needed for function calls.
Affected file
- LSP0ERC725AccountCore.sol (Line: 796, 851)
- LSP14Ownable2Step.sol (Line: 126, 136, 150)
- LSP1UniversalReceiverDelegateUP.sol (Line: 152, 201)
- LSP20CallVerification.sol (Line: 84)
- LSP4DigitalAssetMetadataInitAbstract.sol (Line: 27)
- LSP6ExecuteModule.sol (Line: 153, 170, 188, 317, 339, 366, 382, 399, 418)
- LSP6KeyManagerCore.sol (Line: 441)
- LSP6SetDataModule.sol (Line: 334, 385, 406, 438, 474, 490, 507, 622)
- LSP7CappedSupply.sol (Line: 53)
- LSP7CappedSupplyInitAbstract.sol (Line: 53)
- LSP7CompatibleERC20.sol (Line: 107, 116, 127, 137, 146)
- LSP7CompatibleERC20InitAbstract.sol (Line: 33, 115, 124, 135, 145, 154)
- LSP7CompatibleERC20MintableInitAbstract.sol (Line: 15)
- LSP7DigitalAssetCore.sol (Line: 399)
- LSP7DigitalAssetInitAbstract.sol (Line: 28)
- LSP7MintableInitAbstract.sol (Line: 20)
- LSP8CappedSupply.sol (Line: 56)
- LSP8CappedSupplyInitAbstract.sol (Line: 56)
- LSP8CompatibleERC721.sol (Line: 259, 269, 284, 341)
- LSP8CompatibleERC721InitAbstract.sol (Line: 61, 259, 269, 284, 341)
- LSP8CompatibleERC721MintableInitAbstract.sol (Line: 15)
- LSP8Enumerable.sol (Line: 31)
- LSP8EnumerableInitAbstract.sol (Line: 33)
- LSP8IdentifiableDigitalAssetCore.sol (Line: 394)
- LSP8IdentifiableDigitalAssetInitAbstract.sol (Line: 30)
- LSP8MintableInitAbstract.sol (Line: 19)
- UniversalProfileInitAbstract.sol (Line: 27)
GAS-7: Public functions not called by the contract should be declared external instead
Description
Contracts are allowed to override their parents’ functions and change the visibility from external to public and can save gas by doing so.
Affected file
- LSP0ERC725AccountCore.sol (Line: 171, 380, 460, 734)
- LSP1UniversalReceiverDelegateUP.sol (Line: 78)
- LSP4Compatibility.sol (Line: 25, 34)
- LSP6KeyManagerCore.sol (Line: 87, 107, 118, 152, 204)
- LSP7CompatibleERC20.sol (Line: 56, 66, 79)
- LSP7CompatibleERC20InitAbstract.sol (Line: 64, 74, 87)
- LSP7DigitalAssetCore.sol (Line: 54, 61, 70, 91, 101, 154, 203, 232)
- LSP8CompatibleERC721.sol (Line: 94, 113, 120, 155, 172, 185, 197)
- LSP8CompatibleERC721InitAbstract.sol (Line: 94, 113, 120, 155, 172, 185, 197)
- LSP8Enumerable.sol (Line: 27)
- LSP8EnumerableInitAbstract.sol (Line: 29)
- LSP8IdentifiableDigitalAssetCore.sol (Line: 61, 70, 94, 105, 153, 165, 210)
GAS-8: Storage pointer to a structure is cheaper than copying each value of the structure into memory, same for array and mapping
Description
It may not be obvious, but every time you copy a storage struct/array/mapping to a memory variable, you are literally copying each member by reading it from storage, which is expensive. And when you use the storage keyword, you are just storing a pointer to the storage, which is much cheaper.
Affected file
- LSP0ERC725AccountCore.sol (Line: 176, 244, 308, 469, 472, 503, 504, 742)
- LSP10Utils.sol (Line: 72, 121)
- LSP1UniversalReceiverDelegateUP.sol (Line: 112, 158, 159, 207, 208)
- LSP1Utils.sol (Line: 47, 57)
- LSP20CallVerification.sol (Line: 26, 53)
- LSP2Utils.sol (Line: 35, 56, 78, 100, 119, 144, 166, 185)
- LSP4Compatibility.sol (Line: 26, 35)
- LSP5Utils.sol (Line: 74, 123, 216, 219)
- LSP6ExecuteModule.sol (Line: 259, 289, 445)
- LSP6KeyManagerCore.sol (Line: 160, 220, 336, 356, 402, 420, 424, 470, 486)
- LSP6OwnershipModule.sol (Line: 24)
- LSP6SetDataModule.sol (Line: 128, 788)
- LSP6Utils.sol (Line: 29, 155)
- LSP7DigitalAssetCore.sol (Line: 322, 377, 424)
- LSP8CompatibleERC721.sol (Line: 97, 102, 126, 323)
- LSP8CompatibleERC721InitAbstract.sol (Line: 97, 102, 126, 323)
- LSP8IdentifiableDigitalAssetCore.sol (Line: 346, 375, 426)
GAS-9: Usage of uint/int smaller than 32 bytes (256 bits) incurs overhead
Description
When using elements that are smaller than 32 bytes, your contract’s gas usage may be higher. This is because the EVM operates on 32 bytes at a time. Therefore, if the element is smaller than that, the EVM must use more operations in order to reduce the size of the element from 32 bytes to the desired size.
Each operation involving a uint8 costs an extra 22-28 gas (depending on whether the other operand is also a variable of type uint8) as compared to ones involving uint256, due to the compiler having to clear the higher bits of the memory word before operating on the uint8, as well as the associated stack operations of doing so. Use a larger size then downcast where needed.
Affected file
- LSP10Utils.sol (Line: 83, 89, 115, 133, 136, 140)
- LSP1UniversalReceiverDelegateUP.sol (Line: 139, 139, 139, 201)
- LSP2Utils.sol (Line: 52, 296, 336)
- LSP5Utils.sol (Line: 85, 117, 134, 137, 191)
- LSP6ExecuteModule.sol (Line: 378)
- LSP6KeyManagerCore.sol (Line: 107, 387, 388, 445)
- LSP6SetDataModule.sol (Line: 346, 350, 544, 664)
- LSP6Utils.sol (Line: 98, 128, 202, 205)
- LSP7DigitalAssetCore.sol (Line: 54)
GAS-10: Use assembly to write address storage values
Affected file
- LSP14Ownable2Step.sol (Line: 129, 163)
- LSP6KeyManagerCore.sol (Line: 519, 541, 553)
- LSP7CappedSupply.sol (Line: 28)
- LSP7CappedSupplyInitAbstract.sol (Line: 28)
- LSP8CappedSupply.sol (Line: 30)
- LSP8CappedSupplyInitAbstract.sol (Line: 30)
- LSP8IdentifiableDigitalAssetCore.sol (Line: 268)
GAS-11: Use constants instead of type(uintx).max
Description
It uses more gas in the distribution process and also for each transaction than constant usage.
Affected file
- LSP10Utils.sol (Line: 85, 135)
- LSP5Utils.sol (Line: 87, 190)
- LSP6ExecuteModule.sol (Line: 296, 378, 395, 414)
GAS-12: Use hardcoded address instead address(this)
Description
Instead of using address(this), it is more gas-efficient to pre-calculate and use the hardcoded address
Affected file
- LSP0ERC725AccountCore.sol (Line: 176)
- LSP14Ownable2Step.sol (Line: 127)
- LSP6ExecuteModule.sol (Line: 86)
- LSP6KeyManagerCore.sol (Line: 365)
GAS-13: Use nested if and avoid multiple check combinations
Description
Using nested is cheaper than using && multiple check combinations. There are more advantages, such as easier to read code and better coverage reports.
Affected file
- LSP0ERC725AccountCore.sol (Line: 801)
- LSP10Utils.sol (Line: 76)
- LSP1UniversalReceiverDelegateUP.sol (Line: 227, 245)
- LSP5Utils.sol (Line: 78)
- LSP6ExecuteModule.sol (Line: 165, 214, 224, 228, 233, 236, 240, 301)
- LSP6KeyManagerCore.sol (Line: 338, 404)
- LSP6SetDataModule.sol (Line: 362)
- LSP8CompatibleERC721.sol (Line: 235)
- LSP8CompatibleERC721InitAbstract.sol (Line: 235)
GAS-14: Using > 0 costs more gas than != 0 when used on a uint in a require() statement
Description
When dealing with unsigned integer types, comparisons with != 0 are cheaper then with > 0. This change saves 6 gas per instance.
Affected file
- LSP0ERC725AccountCore.sol (Line: 182, 741)
- LSP1UniversalReceiverDelegateUP.sol (Line: 165)
- LSP20CallVerification.sol (Line: 86)
- LSP7DigitalAssetCore.sol (Line: 491)
- LSP8CompatibleERC721.sol (Line: 313)
- LSP8CompatibleERC721InitAbstract.sol (Line: 313)
- LSP8IdentifiableDigitalAssetCore.sol (Line: 493)
GAS-15: Variable initialized with their default value
Description
Uninitialized variables are assigned with the types default value. Explicitly initializing a variable with it’s default value costs unnecesary gas.
Affected file
- LSP0ERC725AccountCore.sol (Line: 396, 411)
- LSP2Utils.sol (Line: 261, 292, 328)
- LSP6ExecuteModule.sol (Line: 124, 194, 272)
- LSP6KeyManagerCore.sol (Line: 163, 223, 256, 323, 369)
- LSP6SetDataModule.sol (Line: 127, 129, 133)
- LSP6Utils.sol (Line: 94, 123, 172, 173)
- LSP7DigitalAssetCore.sol (Line: 171)
- LSP8IdentifiableDigitalAssetCore.sol (Line: 227, 273)
GAS-16: With assembly, .call (bool success) transfer can be done gas-optimized
Description
return data (bool success,) has to be stored due to EVM architecture, but in a usage in assembly, 'out' and 'outsize' values are given (0,0), this storage disappears and gas optimization is provided.
Affected file
- LSP0ERC725AccountCore.sol (Line: 176, 742)
- LSP1Utils.sol (Line: 57)
- LSP20CallVerification.sol (Line: 26, 53)
- LSP6KeyManagerCore.sol (Line: 420)
GAS-17: abi.encode() is less efficient than abi.encodePacked()
Description
Use abi.encodePacked() where possible to save gas.
Affected file
- LSP0ERC725AccountCore.sol (Line: 253, 319, 528)