EVMole

This library extracts function selectors and arguments from Ethereum Virtual Machine (EVM) bytecode, even for unverified contracts.

• JavaScript, Rust and Python implementations
• Clean code with zero external dependencies (py & js)
• Faster and more accurate than other existing tools
• Tested on Solidity and Vyper compiled contracts

Try it online

Usage

JavaScript

$ npm i evmole

import {functionArguments, functionSelectors} from 'evmole'
// Also supported: const e = require('evmole'); e.functionSelectors();

const code = '0x6080604052348015600e575f80fd5b50600436106030575f3560e01c80632125b65b146034578063b69ef8a8146044575b5f80fd5b6044603f3660046046565b505050565b005b5f805f606084860312156057575f80fd5b833563ffffffff811681146069575f80fd5b925060208401356001600160a01b03811681146083575f80fd5b915060408401356001600160e01b0381168114609d575f80fd5b80915050925092509256'
console.log( functionSelectors(code) )
// Output(list): [ '2125b65b', 'b69ef8a8' ]

console.log( functionArguments(code, '2125b65b') )
// Output(str): 'uint32,address,uint224'

Rust

Documentation available on docs.rs

let code = hex::decode("6080604052348015600e575f80fd5b50600436106030575f3560e01c80632125b65b146034578063b69ef8a8146044575b5f80fd5b6044603f3660046046565b505050565b005b5f805f606084860312156057575f80fd5b833563ffffffff811681146069575f80fd5b925060208401356001600160a01b03811681146083575f80fd5b915060408401356001600160e01b0381168114609d575f80fd5b80915050925092509256").unwrap();

println!("{:x?}", evmole::function_selectors(&code, 0));
// Output(Vec<[u8;4]>): [[21, 25, b6, 5b], [b6, 9e, f8, a8]]

println!("{}", evmole::function_arguments(&code, &[0x21, 0x25, 0xb6, 0x5b], 0));
// Output(String): uint32,address,uint224

Python

$ pip install evmole --upgrade

from evmole import function_arguments, function_selectors

code = '0x6080604052348015600e575f80fd5b50600436106030575f3560e01c80632125b65b146034578063b69ef8a8146044575b5f80fd5b6044603f3660046046565b505050565b005b5f805f606084860312156057575f80fd5b833563ffffffff811681146069575f80fd5b925060208401356001600160a01b03811681146083575f80fd5b915060408401356001600160e01b0381168114609d575f80fd5b80915050925092509256'
print( function_selectors(code) )
# Output(list): ['2125b65b', 'b69ef8a8']

print( function_arguments(code, '2125b65b') )
# Output(str): 'uint32,address,uint224'

Foundry

Foundy's cast uses the Rust implementation of EVMole

$ cast selectors $(cast code 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2)
0x06fdde03	
0x095ea7b3	address,uint256
0x18160ddd	
0x23b872dd	address,address,uint256
...

$ cast selectors --resolve $(cast code 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2)
0x06fdde03	                       	name()
0x095ea7b3	address,uint256        	approve(address,uint256)
0x18160ddd	                       	totalSupply()
0x23b872dd	address,address,uint256	transferFrom(address,address,uint256)
...

See examples for more

Benchmark

function selectors

FP/FN - False Positive/False Negative errors; smaller is better

Dataset		evmole rs · js · py	whatsabi	evm-hound-rs	heimdall-rs	simple
largest1k 1000 contracts 24427 functions	FP contracts	1 🥈	0 🥇	75	18	95
	FN contracts	0 🥇	8	40	102	9
	FP functions	192 🥈	0 🥇	720	600	749
	FN functions	0 🥇	8 🥈	191	113	12
	Time	0.5s · 1.5s · 2.0s	2.6s	0.7s	719.9s	1.7s
random50k 50000 contracts 1171102 functions	FP contracts	1 🥇	43	693	waiting fixes	4136
	FN contracts	9 🥇	31	2903		77
	FP functions	3 🥇	51	10798		14652
	FN functions	10 🥇	32	3538		96
	Time	10.1s · 19.4s · 39.4s	46.9s	11.5s		47.9s
vyper 780 contracts 21244 functions	FP contracts	0 🥇	30	19	0	185
	FN contracts	0 🥇	780	300	780	480
	FP functions	0 🥇	30	19	0	197
	FN functions	0 🥇	21244	8273	21244	12971
	Time	0.4s · 0.8s · 1.2s	2.0s	0.4s	16.4s	1.1s

function arguments

Errors - when at least 1 argument is incorrect: (uint256,string) != (uint256,bytes); smaller is better

Dataset		evmole rs · js · py	heimdall-rs	simple
largest1k 1000 contracts 24427 functions	Errors	14.7%, 3598 🥇	42.7%, 10421	58.3%, 14242
	Time	0.7s · 7.3s · 14.4s	724.4s	0.6s
random50k 50000 contracts 1171102 functions	Errors	5.0%, 58286 🥇	waiting fixes	54.9%, 643213
	Time	23.0s · 243.8s · 635.6s		9.6s
vyper 780 contracts 21244 functions	Errors	50.7%, 10763 🥇	100.0%, 21244	56.8%, 12077
	Time	0.7s · 7.3s · 14.4s	16.8s	0.5s

See benchmark/README.md for the methodology and commands to reproduce these results

versions: evmole (4ba4c505); whatsabi v0.11.0; evm-hound-rs v0.1.4; heimdall-rs v0.7.3

How it works

Short: Executes code with a custom EVM and traces CALLDATA usage.

Long: TODO

License

MIT