WTF Gas Optimization

Solidity gas optimization techniques, using Foundry. 总结写 Solidity 智能合约更省 gas 的技巧。

Lead by @0xKaso

大纲

1. use constant and immutable

2. use calldata over memory

3. use Bitmap

4. use unchecked

5. use uint256 over uint8

6. use custom error over require/assert

7. use local variable over storage

8. use clone2 over new/create2

9. packing storage slots

10. use ++i as better increment

11. use uint in reentrancy guard

12. use < over <=

1. use constant and immutable

Code | 文章

Testing

forge test --contracts 01_Constant/Constant.t.sol --gas-report

Gas report

Function Name	Gas Cost
varConstant	161 ✅
varImmutable	161 ✅
variable	2261

2. use calldata over memory

Code | 文章

Testing

forge test --contracts 02_CalldataAndMemory/CalldataAndMemory.T.sol --gas-report

Gas report

Function Name	Gas Cost
writeByCalldata	67905 ✅
writeByMemory	68456

3. use Bitmap

Code | 文章

Testing

forge test --contracts 03_Bitmap/Bitmap.T.sol --gas-report

Gas report

Function Name	Gas Cost
setDataWithBitmap	22366 ✅
setDataWithBoolArray	35729

4. use unchecked

Code | 文章

Testing

forge test --contracts 04_unchecked/Unchecked.T.sol --gas-report

Gas report

Function Name	Gas Cost
forNormal	1910309
forUnckecked	570287 ✅

5. use uint256 over uint8

Code | 文章

Testing

forge test --contracts 05_uint/Uint.T.sol --gas-report

Gas report

Function Name	Gas Cost
read Uint8	2379
read Uint128	2465
read Uint256	2317 ✅
set Uint8	5355
set Uint128	5358
set Uint256	5322 ✅

6. use custom error over require/assert

Code | 文章

Testing

forge test --contracts 06_Error/Error.T.sol --gas-report

Gas report

Error Name	Gas Cost
Assert	180
Require	268
Revert	164 ✅

7. use local variable over storage

Code | 文章

Testing

forge test --contracts 07_LocalData/LocalData.T.sol --gas-report

Gas report

Data Type	Gas Cost
localData	1902339 ✅
storageData	4022155

8. use clone2 over new/create2

Code | 文章

Testing

forge test --contracts 08_Clone2/Clone2.T.sol --gas-report

Gas report

Create Type	Gas Cost
clone2	41493 ✅
create2	93031
new	79515

9. packing storage slots

Code | 文章

Testing

forge test --contracts 09_Packing/Packing.T.sol --gas-report

Gas report

Create Type	Gas Cost
normal	133521
packing	111351 ✅

10. use ++i as better increment

Code | 文章

forge test --contracts 10_Increment/Increment.T.sol --gas-report

Gas report

Increment	Gas Cost
i += 1	270
i = i +1	248
i++	220
++i	193 ✅

11. use Uint in Reentrancy Guard

Code | 文章

Testing

forge test --contracts 11_ReentrancyGuard/ReentrancyGuard.T.sol --gas-report

Gas report

ReentrancyGuard	Gas Cost	tips
Bool	27757
Uint01	27604	0 to non-zero -> 20000 gas
Uint12	13908 ✅	non-zero to non-zero -> 2900 gas

12. use < over <=

Code | 文章

Testing

forge test --contracts 12_LessThan/LessThan.t.sol --gas-report

Gas report

Operator	Gas Cost
<=	250
<	247 ✅

WTF Gas Optimization 贡献者

贡献者是WTF学院的基石