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https://github.com/taka-security/sslc
cli tool to check Solidity storage memory layout of structs for inefficiencies
https://github.com/taka-security/sslc
checker cli ethereum layout memory solidity storage struct
Last synced: 16 days ago
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cli tool to check Solidity storage memory layout of structs for inefficiencies
- Host: GitHub
- URL: https://github.com/taka-security/sslc
- Owner: Taka-Security
- License: mit
- Created: 2019-04-01T15:43:43.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2022-12-30T17:24:11.000Z (almost 2 years ago)
- Last Synced: 2024-10-30T06:00:27.851Z (19 days ago)
- Topics: checker, cli, ethereum, layout, memory, solidity, storage, struct
- Language: JavaScript
- Homepage:
- Size: 187 KB
- Stars: 8
- Watchers: 4
- Forks: 1
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# **S**olidity **S**torage **L**ayout **C**hecker
[](https://www.npmjs.com/package/sslc)
Given some Solidity smart contract(s), extract all structs and check if their members could be laid out more efficient (=occupy less storage slots).
#### Timeout
If the number of struct members is sufficiently high, the algorithm to find the most efficient layout
will run "indefinitely". To guard against this, there is a default 10 second timeout to calculate
the most efficient layout of any given struct. If the timeout is exceeded the calculation will exit and
give the "current best slot count" as well as info that the timeout was reached. This timeout can be
customized using the `-t ` argument.
## Dependencies
Makes use of [solidity-parser-antlr](https://github.com/federicobond/solidity-parser-antlr) to parse Solidity files.
## Usage
```
usage: sslc [-h] [-v] -f path [path ...] [-oj path] [-ot path]
Solidity storage layout checker
Optional arguments:
-h, --help Show this help message and exit.
-v, --version Show program's version number and exit.
-f path [path ...] input solidity file(s), supports glob
-oj path write output to JSON file
-ot path write output to text file
-t secs brute force timeout, default 10s
```
#### without install
```
npx sslc -f ~/my-solidity-project/contracts/*.sol
```
#### with install
```
npm i -g sslc
sslc -f ~/my-solidity-project/contracts/*.sol
```
## Output
The script will print text output using Solidity syntax to stdout.
It is also possible to save the text output to a file and/or save JSON output to a file.
#### Text output
```Solidity
struct MyFirstStruct { // file: SomeContract.sol | contract: SomeContract
uint8 myFirstVar; // bytes: 1
//---------- end of slot | bytes taken: 1 | bytes free: 31
bytes32[] mySecondVar; // bytes: 32
//---------- end of slot | bytes taken: 32 | bytes free: 0
bool myThirdVar; // bytes: 1
//---------- end of slot | bytes taken: 1 | bytes free: 31
uint256 myFourthVar; // bytes: 32
//---------- end of slot | bytes taken: 32 | bytes free: 0
bool myFourthVar; // bytes: 1
//---------- end of slot | bytes taken: 1 | bytes free: 31
} // slots that can be saved = 2
struct MyParentStruct { // file: SomeOtherContract.sol | contract: ParentContract
uint8 myFirstVar; // bytes: 1
//---------- end of slot | bytes taken: 1 | bytes free: 31
uint256 mySecondVar; // bytes: 32
//---------- end of slot | bytes taken: 32 | bytes free: 0
uint16 myThirdVar; // bytes: 2
//---------- end of slot | bytes taken: 2 | bytes free: 30
} // slots that can be saved = 1
struct MyOtherStruct { // file: SomeOtherContract.sol | contract: SomeOtherContract
uint256 myFirstVar; // bytes: 32
//---------- end of slot | bytes taken: 32 | bytes free: 0
address mySecondVar; // bytes: 20
//---------- end of slot | bytes taken: 20 | bytes free: 12
} // slots that can be saved = 0
// STRUCTS THAT CAN BE OPTIMIZED
// =============================
// file: SomeContract.sol
// contract: SomeContract
// struct: MyFirstStruct
// slots saved: 2
// -----------------------------
// file: SomeOtherContract.sol
// contract: ParentContract
// struct: MyParentStruct
// slots saved: 1
// -----------------------------
```
#### JSON output
```json
[
{
"file": "SomeContract.sol",
"contract": "SomeContract",
"struct": "MyFirstStruct",
"slotsSaved": 2,
"timedout": false
},
{
"file": "SomeOtherContract.sol",
"contract": "ParentContract",
"struct": "MyParentStruct",
"slotsSaved": 1,
"timedout": false
}
]
```
## Test
`npm test`
## TODO
- do the same for the layout of variables of a given contract
## License
MIT