hjawhar/evm

An ethereum virtual machine (EVM) bytecode decompiler

EVM Bytecode Decompiler

An Ethereum Virtual Machine (EVM) interpreter and decompiler, along with several other utils for programmatically extracting information from bytecode.

Usage

npm i evm

Features

• Converting bytecode to opcodes
• Reading information like events or functions from either bytecode or tx data
• Extracting the swarm hash (if any) from bytecode

API

Methods

• getBytecode() - Get raw bytecode (not really useful; same as input)
• getOpcodes() - Returns opcodes including pc and pushData (if included)
• getFunctions() - Parse functions from their signatures in bytecode
• getEvents() - Parse events from their signatures in bytecode
• getJumpDestinations() - Get array of program counters from JUMPDEST opcodes
• getSwarmHash() - Get Swarm hash (if any) for contract metadata
• reset() - Reset the EVM state (stack, memory, etc.)
• parse() - Interpret opcodes by looping over them, returns array of interpreted opcodes
• decompile() - Decompile bytecode into readable Solidity-like pseudocode

Examples

Converting bytecode to opcodes

Node.js

const { EVM } = require("evm");
const Web3 = require('web3');
const web3 = new Web3(new Web3.providers.HttpProvider("https://api.mycryptoapi.com/eth"));

web3.eth.getCode("0x06012c8cf97BEaD5deAe237070F9587f8E7A266d").then(code => {  /* CryptoKitties contract */
    const evm = new EVM(code);
    console.log(evm.getOpcodes());  /* Get opcodes */
});

Browser

const { EVM } = window.EVM_Utils;
const web3 = new Web3(window.web3.currentProvider);
web3.eth.getCode("0x89d24A6b4CcB1B6fAA2625fE562bDD9a23260359", function(err,code) {  /* DAI contract */
    if(err) throw err;
    const evm = new EVM(code);
    console.log(evm.getOpcodes());  /* Get opcodes */
});

Decompiling a contract

Node.js

const { EVM } = require("evm");
const Web3 = require('web3');
const web3 = new Web3(new Web3.providers.HttpProvider("https://api.mycryptoapi.com/eth"));

web3.eth.getCode("0x06012c8cf97BEaD5deAe237070F9587f8E7A266d").then(code => {  /* CryptoKitties contract */
    const evm = new EVM(code);
    console.log(evm.getFunctions());  /* Get functions */
    console.log(evm.getEvents());  /* Get events */
    console.log(evm.decompile());  /* Decompile bytecode */
});

Browser

const { EVM } = window.EVM;
const web3 = new Web3(window.web3.currentProvider);
web3.eth.getCode("0x89d24A6b4CcB1B6fAA2625fE562bDD9a23260359", function(err,code) {  /* DAI contract */
    if(err) throw err;
    const evm = new EVM(code);
    console.log(evm.getFunctions());  /* Get functions */
    console.log(evm.getEvents());  /* Get events */
    console.log(evm.decompile());  /* Decompile bytecode */
});

Extracting data from transaction

Node.js

const { Transaction } = require("evm");
const Web3 = require('web3');
const web3 = new Web3(new Web3.providers.HttpProvider("https://api.mycryptoapi.com/eth"));

web3.eth.getTransaction("0xd20a8d888a3f29471ea41ea77cc2d95ccd79ade1eaad059e83524e72b9adf962").then(transactionData => {
    const transaction = new Transaction();
    transaction.setInput(transactionData.input);
    console.log(transaction.getFunction());  /* Get function */
});

Browser

const { Transaction } = window.EVM;
const web3 = new Web3(window.web3.currentProvider);
web3.eth.getTransaction("0xd20a8d888a3f29471ea41ea77cc2d95ccd79ade1eaad059e83524e72b9adf962", function(err,transactionData) {
    if(err) throw err;
    const transaction = new Transaction();
    transaction.setInput(transactionData.input);
    console.log(transaction.getFunction());  /* Get function */
});