zkSync Era: Vyper Compiler

zkSync Era is a layer 2 rollup that uses zero-knowledge proofs to scale Ethereum without compromising on security or decentralization. As it's EVM-compatible (with Solidity/Vyper), 99% of Ethereum projects can redeploy without needing to refactor or re-audit any code. zkSync Era also uses an LLVM-based compiler that will eventually enable developers to write smart contracts in popular languages such as C++ and Rust.

This repository contains the compiler from Vyper to zkEVM bytecode.

Building

1. Install some tools system-wide:
   1.a. apt install cmake ninja-build clang-13 lld-13 parallel on a Debian-based Linux, with optional musl-tools if you need a musl build
   1.b. pacman -S cmake ninja clang lld parallel on an Arch-based Linux
   1.c. On MacOS, install the HomeBrew package manager (being careful to install it as the appropriate user), then brew install cmake ninja coreutils parallel. Install your choice of a recent LLVM/Clang compiler, e.g. via Xcode, Apple’s Command Line Tools, or your preferred package manager.
   1.d. Their equivalents with other package managers

2. Install Rust

   Currently we are not pinned to any specific version of Rust, so just install the latest stable build for your platform.
   Also install the musl target if you are compiling on Linux in order to distribute the binary:
   rustup target add x86_64-unknown-linux-musl

3. Check out or clone the appropriate branch of this repository.

4. Go to the project root and run git checkout <ref> with the tag, branch, or commit you want to build.

5. Install the zkEVM LLVM framework builder:
   5.a. cargo install compiler-llvm-builder on MacOS, or Linux for personal use
   5.b. cargo install compiler-llvm-builder --target x86_64-unknown-linux-musl on Linux for distribution

   The builder is not the zkEVM LLVM framework itself; it is just a tool that clones our repository and runs the sequence of build commands. By default it is installed in ~/.cargo/bin/, which is recommended to be added to your $PATH. Execute zkevm-llvm --help for more information. If you need a specific branch of zkEVM LLVM, change it in the LLVM.lock file at the root of this repository.

6. Run the builder to clone and build the zkEVM LLVM framework at this repository root:
   6.1. zkevm-llvm clone
   6.2. zkevm-llvm build

7. Build the Vyper compiler executable:
   7.a. cargo build --release on MacOS or Linux for personal use
   7.b. cargo build --release --target x86_64-unknown-linux-musl on Linux for distribution

8. If you need to move the built binary elsewhere, grab it from the build directory:
   8.a. On MacOS or Linux for the default target:
   ./target/release/zkvyper
   8.b. On Linux, if you are building for the target x86_64-unknown-linux-musl:
   ./target/x86_64-unknown-linux-musl/release/zkvyper

Usage

Check ./target/*/zkvyper --help for compiler usage.

Version 0.3.3 of Vyper compiler must be available in PATH, or the --vyper option must be used instead.

For big projects it is more convenient to use the compiler via the hardhat plugin. For single-file contract or small projects, however, the CLI is more than fine.

Troubleshooting

• If you get a “failed to authenticate when downloading repository… if the git CLI succeeds then net.git-fetch-with-cli may help here” error, then prepending the cargo command with CARGO_NET_GIT_FETCH_WITH_CLI=true may help.
• On MacOS, git config --global credential.helper osxkeychain followed by cloning a repository manually with a personal access token may help.
• Unset any LLVM-related environment variables you may have set, especially LLVM_SYS_<version>_PREFIX (see e.g. https://crates.io/crates/llvm-sys and https://llvm.org/docs/GettingStarted.html#local-llvm-configuration). To make sure: set | grep LLVM

License

The Vyper compiler is distributed under the terms of either

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Resources

Vyper documentation

Vyper LLL IR

Some parts of the documentation may be outdated.
Please contact the Vyper team for assistance.

Official Links

• Website
• GitHub
• Twitter
• Twitter for Devs
• Discord

Disclaimer

zkSync Era has been through extensive testing and audits, and although it is live, it is still in alpha state and will undergo further audits and bug bounty programs. We would love to hear our community's thoughts and suggestions about it! It's important to note that forking it now could potentially lead to missing important security updates, critical features, and performance improvements.