evmone

Fast Ethereum Virtual Machine implementation

evmone is a C++ implementation of the Ethereum Virtual Machine (EVM). Created by members of the Ipsilon (ex-Ewasm) team, the project aims for clean, standalone EVM implementation that can be imported as an execution module by Ethereum Client projects. The codebase of evmone is optimized to provide fast and efficient execution of EVM smart contracts.

Characteristic of evmone

1. Exposes the EVMC API.
2. Requires C++20 standard.
3. The intx library is used to provide 256-bit integer precision.
4. The ethash library is used to provide Keccak hash function implementation needed for the special KECCAK256 instruction.
5. Contains two interpreters:
   • Baseline (default)
   • Advanced (select with the advanced option)

Baseline Interpreter

1. Provides relatively straight-forward but efficient EVM implementation.
2. Performs only minimalistic JUMPDEST analysis.

Advanced Interpreter

1. The indirect call threading is the dispatch method used - a loaded EVM program is a table with pointers to functions implementing virtual instructions.
2. The gas cost and stack requirements of block of instructions is precomputed and applied once per block during execution.
3. Performs extensive and expensive bytecode analysis before execution.

Usage

As geth plugin

evmone implements the EVMC API for Ethereum Virtual Machines. It can be used as a plugin replacing geth's internal EVM. But for that a modified version of geth is needed. The Ewasm's fork of go-ethereum provides binary releases of geth with EVMC support.

Next, download evmone from Releases.

Start the downloaded geth with --vm.evm option pointing to the evmone shared library.

geth --vm.evm=./libevmone.so

Building from source

To build the evmone EVMC module (shared library), test, and benchmark:

1. Fetch the source code:

   git clone --recursive https://github.com/ethereum/evmone
   cd evmone

2. Configure the project build and dependencies:

   Linux / OSX

   cmake -S . -B build -DEVMONE_TESTING=ON

   Windows

   cmake -S . -B build -DEVMONE_TESTING=ON -G "Visual Studio 16 2019" -A x64

3. Build:

   cmake --build build --parallel

4. Run the unit tests or benchmarking tool:

   build/bin/evmone-unittests
   build/bin/evmone-bench test/evm-benchmarks/benchmarks

Precompiles

Ethereum Precompiled Contracts (precompiles for short) are only partly supported by evmone.

However, there are options to enable limited precompiles support for testing.

1. For precompiles with missing implementation stubs are enabled by default. They will correctly respond to known inputs.
2. The CMake option EVMONE_PRECOMPILES_SILKPRE=1 enables building of the silkpre third party library with the implementation of the precompiles. This library also requires GMP (e.g. libgmp-dev) library for building and execution.

Tools

evm-test

The evm-test executes a collection of unit tests on any EVMC-compatible Ethereum Virtual Machine implementation. The collection of tests comes from the evmone project.

evm-test ./evmone.so

Docker

Docker images with evmone are available on Docker Hub: https://hub.docker.com/r/ethereum/evmone.

Having the evmone shared library inside a docker is not very useful on its own, but the image can be used as the base of another one or you can run benchmarks with it.

docker run --entrypoint evmone-bench ethereum/evmone /src/test/benchmarks

EVM Object Format (EOF) support

evmone supports EOFv1. Since EOF validation is done once during deploy-time, evmone does not revalidate during execution of bytecode. To force EOF revalidation, you can use the validate_eof option, example:

evmc run --vm libevmone.so,validate_eof --rev 14 "EF00"

References

1. Efficient gas calculation algorithm for EVM

Maintainer

Paweł Bylica @chfast

License

Licensed under the Apache License, Version 2.0.