echoevm

EchoEVM is a minimal, pedagogical Ethereum Virtual Machine (EVM) implementation written in Go. It focuses on transparent bytecode execution, traceability, and ease of experimentation rather than production consensus or networking features.

🆕 What's New in v0.0.14

Nested Array Support: ABI encoding/decoding for uint256[][], address[][], etc.
New Precompiles: Added support for MODEXP (0x05), BN256 Add/Mul/Pairing (0x06-0x08), Blake2F (0x09).
Fork-Specific Behavior: Infrastructure to handle different hardfork rules (Merge, London active by default).

Previous v0.0.13

Precompiled Contracts: Native support for ECRECOVER (0x01), SHA256 (0x02), RIPEMD160 (0x03), IDENTITY (0x04)
Tuple ABI Encoding: Encode struct-like parameters using (val1,val2,...) syntax

See ROADMAP.md for the complete version history.

✨ Features

Category	Features
Execution	Constructor deployment, runtime calls, bytecode disassembly
ABI Support	Function selector encoding, primitives, arrays, bytes types
Tracing	JSON structured per-opcode tracing with pre/post state
Gas Metering	EIP-2929 compatible dynamic gas calculations
EIP Support	EIP-1153 (Transient Storage), EIP-5656 (MCOPY)
Precompiles	ECRECOVER, SHA256, RIPEMD160, IDENTITY (0x01-0x04)
Testing	Unit tests, integration tests, Ethereum compliance tests
Logging	Zerolog-based structured logging (plain/JSON output)

✅ Requirements

Go 1.23.2+
(Optional) solc for compiling .sol files directly

🔧 Installation

From source:

go install github.com/smallyunet/echoevm/cmd/echoevm@latest

Clone and build:

git clone https://github.com/smallyunet/echoevm.git
cd echoevm
make build
make install   # install into GOPATH/bin

Verify:

echoevm --help

🚀 Quick Start

Run bytecode directly

# Simple arithmetic: PUSH1 1 PUSH1 2 ADD
echoevm run 6001600201

# With debug trace
echoevm run --debug 6001600201

Deploy and call a contract

# Deploy constructor bytecode
echoevm deploy -a ./artifacts/Add.json --print

# Call a function with ABI encoding
echoevm call -a ./artifacts/Add.json -f add(uint256,uint256) -A 2,40

# Generate execution trace
echoevm trace -a ./artifacts/Add.json -f add(uint256,uint256) -A 7,9 --full | jq .

Interactive REPL

echoevm repl
# Type opcodes: PUSH1 10 PUSH1 20 ADD

🖥 CLI Commands

Command	Description
`run`	Execute raw bytecode with optional debug tracing
`deploy`	Run constructor and extract runtime bytecode
`call`	Execute runtime bytecode with ABI encoding
`trace`	JSON line trace of opcode execution
`disasm`	Disassemble bytecode to human-readable opcodes
`repl`	Interactive EVM shell
`version`	Display build metadata

Global Flags

--log-level, -L   Log level (trace|debug|info|warn|error)
--output, -o      Output format (plain|json)
--config, -c      Config file path (reserved)
--rpc-url         Ethereum RPC endpoint

Command Examples

deploy - Execute constructor bytecode

echoevm deploy -a ./artifacts/Add.json --print
echoevm deploy -b ./constructor.bin --out-file runtime.bin

disasm - Disassemble bytecode

# From hex
echoevm disasm 6001600201
# Output:
# 0000: PUSH1 01
# 0002: PUSH1 02
# 0004: ADD

# From artifact
echoevm disasm -a ./artifacts/Add.json --runtime

# JSON output
echoevm disasm -o json 6001600201

call - Execute runtime bytecode

# With ABI encoding
echoevm call -a ./artifacts/Add.json -f add(uint256,uint256) -A 2,40

# With raw calldata
echoevm call -r ./runtime.bin -d 771602f70000...

trace - Execution trace

# First 40 steps
echoevm trace -a ./artifacts/Add.json -f add(uint256,uint256) -A 1,2 --limit 40 | jq .

# Full pre/post state
echoevm trace -a ./artifacts/Loops.json -f forLoop(uint256) -A 5 --full | jq .

📦 ABI Encoding

Supported types for --function/--args encoding:

Type	Examples
Integers	`uint8`, `uint256`, `int128`, etc.
Boolean	`true`, `false`
Address	`0x742d35Cc...` (40 hex chars)
String	UTF-8 dynamic strings
Bytes	`bytes` (dynamic), `bytes32` (fixed)
Arrays	`uint256[]`, `address[]`

Array syntax:

echoevm call -a ./artifacts/Sum.json -f sum(uint256[]) -A "[1;2;3;4;5]"
echoevm call -a ./artifacts/Multi.json -f send(address[]) -A "[0xabc...;0xdef...]"

Note: Tuples and nested arrays are supported.

🧪 Testing

make test             # Run all tests (unit, integration, compliance)
make test-unit        # Run Go unit tests
make test-integration # Run integration tests
make test-compliance  # Run Ethereum compliance tests
make setup-tests      # Download test fixtures (~100MB)

🏗 Architecture

echoevm/
├── cmd/echoevm/     # CLI commands (deploy, call, trace, etc.)
├── internal/
│   ├── evm/
│   │   ├── core/    # Stack, memory, opcode table
│   │   └── vm/      # Interpreter, opcode implementations
│   ├── config/      # Constants, environment variables
│   ├── logger/      # Zerolog wrapper
│   └── errors/      # Error definitions
├── tests/           # Integration and compliance tests
└── docs/            # Documentation

Supported Opcode Categories

Arithmetic, Bitwise, Comparison, Stack, Memory, Storage, Control Flow, Environment, Call/Return/Revert, Logging, System.

⚙️ Configuration

See Configuration and Logging Guide for details.

Environment variables:

export ECHOEVM_LOG_LEVEL=debug
export ECHOEVM_GAS_LIMIT=30000000
export ECHOEVM_ETHEREUM_RPC="https://mainnet.infura.io/v3/<key>"

🚦 Exit Codes

Code	Meaning
0	Successful execution
1	Execution reverted (REVERT)
2	Invalid arguments / configuration error

🗺 Roadmap

See ROADMAP.md for the complete development roadmap.

Upcoming: - Tuple and nested array ABI support - Fork-specific opcode behavior (Cancun) - Improved compliance test coverage - Web-based debugger UI

🤝 Contributing

Fork the repository
Create a feature branch (feat/<topic>)
Add/update tests
Run make test and ensure build is clean
Open a PR with clear description

Issues and discussions for roadmap ideas are welcome!

📄 License

This project is open source under the MIT License. See LICENSE for details.

If you're using EchoEVM in research, experiments, or education, a citation or link back is appreciated.