Overview

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Type Definition

import type { brand } from 'tevm/brand';

export type BrandedBytecode = Uint8Array & { readonly [brand]: "Bytecode" };

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Native Uint8Array Methods

• setFromBase64() - Populate from base64 string
• setFromHex() - Populate from hex string
• toBase64() - Encode to base64 string
• toHex() - Encode to hex string

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Quick Reference

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Effect Schema

import { BytecodeSchema } from '@tevm/voltaire/Bytecode/effect'

const code = BytecodeSchema.fromHex('0x6001')
code.toHex() // '0x6001'

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API Methods

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Constructors

• from(value) - Universal constructor from any input
• fromHex(hex) - Parse hex string (with or without 0x prefix)
• fromUint8Array(bytes) - Create from Uint8Array

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Iteration

• scan(bytecode, options?) - Iterator for lazy bytecode traversal with fusion detection

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Analysis

• analyze(bytecode) - Complete analysis (validation + jump destinations + instructions)
• analyzeBlocks(bytecode, options?) - Split into basic blocks with control flow metadata
• analyzeGas(bytecode, options?) - Estimate gas costs with instruction/block breakdown
• analyzeStack(bytecode, options?) - Validate stack depth constraints and track effects
• analyzeJumpDestinations(bytecode) - Find all JUMPDEST positions
• parseInstructions(bytecode) - Parse all instructions with PUSH data
• isValidJumpDest(bytecode, offset) - Check if position is valid jump target
• detectFusions(bytecode) - Identify multi-instruction optimization patterns

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Validation

• validate(bytecode) - Validate bytecode structure

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Metadata

• hasMetadata(bytecode) - Check for compiler metadata
• stripMetadata(bytecode) - Remove metadata from bytecode

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Formatting

• formatInstructions(bytecode) - Disassemble to string array
• prettyPrint(bytecode, options?) - Annotated disassembly with colors and metadata

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Conversions

• toHex(bytecode) - Convert to hex string with 0x prefix
• toAbi(bytecode) - Extract ABI from bytecode using reverse engineering

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Utilities

• size(bytecode) - Get byte length
• equals(a, b) - Compare bytecode equality
• hash(bytecode) - Compute keccak256 hash
• extractRuntime(bytecode) - Extract runtime code from deployment bytecode
• getBlock(bytecode, pc) - Get basic block containing a program counter
• getNextPc(bytecode, currentPc) - Get next program counter after instruction

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Reference

• Instruction Types - Complete OpcodeData union reference (40+ types)
• Synthetic Opcodes - Extended opcode set for fusion patterns

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Types

import type { brand } from 'tevm/brand';

export type BrandedBytecode = Uint8Array & {
  readonly [brand]: "Bytecode";
};

type BytecodeLike =
  | Uint8Array
  | BrandedBytecode
  | Bytecode
  | Hex
  | string;

export type Opcode = number;

export type Instruction = {
  readonly opcode: Opcode;
  readonly position: number;
  readonly pushData?: Uint8Array;
};

export type Analysis = {
  readonly valid: boolean;
  readonly jumpDestinations: ReadonlySet<number>;
  readonly instructions: readonly Instruction[];
};

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Usage Patterns

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Analyzing Contract Bytecode

const bytecode = await provider.getCode("0x...");
const code = Bytecode(bytecode);

const analysis = code.analyze();
console.log(`Valid: ${analysis.valid}`);
console.log(`Jump destinations: ${analysis.jumpDestinations.size}`);
console.log(`Instructions: ${analysis.instructions.length}`);

const isValidTarget = code.isValidJumpDest(100);

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Comparing Bytecode

const deployed = Bytecode(await provider.getCode(address));
const expected = Bytecode(compiledBytecode);

if (deployed.equals(expected)) {
  console.log("Contract verified");
} else {
  console.log(`Hash deployed: ${deployed.hash()}`);
  console.log(`Hash expected: ${expected.hash()}`);
}

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Extracting Runtime Code

const deploymentCode = Bytecode("0x608060...");
const runtimeCode = deploymentCode.extractRuntime();
const cleanCode = runtimeCode.stripMetadata();

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Tree-Shaking

// Import specific functions (tree-shakeable)
import { fromHex, analyze, formatInstructions } from 'tevm/BrandedBytecode';

const code = fromHex("0x6001");
const analysis = analyze(code);
const disassembly = formatInstructions(code);

// Only these 3 functions included in bundle

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Related

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Core Documentation

• Fundamentals - Learn bytecode structure and parsing
• Instruction Types - Complete OpcodeData union reference

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Advanced Features

• Pretty Print - Annotated disassembly with visualization
• Analyze Blocks - Basic block analysis and CFG
• Detect Fusions - Multi-instruction pattern detection
• Synthetic Opcodes - Extended opcode set

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Related Primitives

• Opcode - EVM instruction definitions and gas costs
• Keccak256 - Keccak256 hashing for bytecode verification
• Hex - Hex string encoding and decoding

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Specification

• Ethereum Yellow Paper - Formal EVM specification
• EVM Opcodes - Interactive opcode reference
• wolflo/evm-opcodes - Gas costs and opcode details
• Solidity Metadata - Contract metadata format