cairo-vm 0.1.3

Blazing fast Cairo interpreter
Documentation

⚡ Cairo-rs ⚡

A faster and safer implementation of the Cairo VM in Rust

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Table of Contents

⚠️ Disclaimer

🚧 cairo-rs is still being built therefore breaking changes might happen often so use it at your own risk. 🚧 Cargo doesn't comply with semver, so we advise to pin the version to 0.1.0. This can be done adding cairo-vm = "0.1.0" to your Cargo.toml

📖 About

Cairo VM is the virtual machine for the Cairo language.

There's an older version of Cairo VM written in Python, which is currently in production.

This repository contains the newer version, written in Rust. It's faster and has safer and more expressive typing. Once completed, it will replace the older one as the sole Cairo VM.

The Cairo language

Cairo is the first production-grade platform for generating STARK proofs for general computation.

It's Turing-complete and it was created by Starkware as part of the Starknet ecosystem.

🌅 Getting Started

Dependencies

Required

Optional

These dependencies are only necessary in order to run the original VM and compile Cairo programs.

  • PyEnv with Python 3.9
  • cairo-lang

🚀 Usage

Running cairo-rs

To compile the repository, run:

cargo build --release

Once the binary is built, it can be found in target/release/ under the name cairo-rs-run.

To compile a program, use cairo-compile [path_to_the_.cairo_file] --output [desired_path_of_the_compiled_.json_file]. For example:

cairo-compile cairo_programs/abs_value_array.cairo --output cairo_programs/abs_value_array_compiled.json

To run a compiled .json program through the VM, call the executable giving it the path and name of the file to be executed. For example:

target/release/cairo-rs-run cairo_programs/abs_value_array_compiled.json --layout all

The flag --layout determines which builtins can be used. More info about layouts here.

To sum up, the following code will get you from zero to running a Cairo program:

git clone https://github.com/lambdaclass/cairo-rs.git

cd cairo-rs

cargo build --release

cairo-compile cairo_programs/abs_value_array.cairo --output cairo_programs/abs_value_array_compiled.json

target/release/cairo-rs-run cairo_programs/abs_value_array_compiled.json --layout all

Using hints

Currently, as this VM is under construction, it's missing some of the features of the original VM. Notably, this VM only implements a limited number of Python hints at the moment, while the Python Cairo VM allows users to run any Python code.

There are two ways to use non-standard hints in this VM:

  • Extend the cairo-rs code and build your own binary using the interface hint processor
  • Use cairo-rs-py which supports running any arbitrary hint in a Python interpreter.

Running a function in a Cairo program with arguments

When running a Cairo program directly using the Cairo-rs repository you would first need to prepare a couple of things.

  1. Specify the Cairo program you want to run
let program =
        Program::from_file(Path::new(&file_path), None);
  1. Instantiate the VM, the cairo_runner, the hint processor, and the entrypoint
let mut vm = VirtualMachine::new(false);

let mut cairo_runner = CairoRunner::new(&program, "all", false);

let mut hint_processor = BuiltinHintProcessor::new_empty();

let entrypoint = program
        .identifiers
        .get(&format!("__main__.{}", &func_name))?
        .pc;
  1. Lastly, initialize the builtins and segments.
cairo_runner.initialize_builtins(&mut vm)?;
cairo_runner.initialize_segments(&mut vm, None);

When using cairo-rs with the Starknet devnet there are additional parameters that are part of the OS context passed on to the run_from_entrypoint method that we do not have here when using it directly. These parameters are, for example, initial stacks of the builtins, which are the base of each of them and are needed as they are the implicit arguments of the function.

 let _var = cairo_runner.run_from_entrypoint(
            entrypoint,
            vec![
                &mayberelocatable!(2),  //this is the entry point selector
                &MaybeRelocatable::from((2,0)) //this would be the output_ptr for example if our cairo function uses it
                ],
            false,
            true,
            true,
            &mut vm,
            &mut hint_processor,
        );

WebAssembly Demo

A demo on how to use cairo-rs with WebAssembly can be found here.

Testing

To run the test suite:

make test

📊 Benchmarks

Running a Cairo program that gets the 1000th Fibonacci number we got the following benchmarks:

Run the benchmark suite with cargo:

cargo bench

📜 Changelog

Keeps track of the latest changes here.

🛠 Contributing

The open-source community is a fantastic place for learning, inspiration, and creation, and this is all thanks to contributions from people like you. Your contributions are greatly appreciated.

If you have any suggestions for how to improve the project, please feel free to fork the repo and create a pull request, or open an issue with the tag 'enhancement'.

  1. Fork the Project
  2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
  3. Commit your Changes (git commit -m 'Add some AmazingFeature')
  4. Push to the Branch (git push origin feature/AmazingFeature)
  5. Open a Pull Request

And don't forget to give the project a star! ⭐ Thank you again for your support.

🌞 Related Projects

  • starknet_in_rust: implementation of Starknet in Rust, powered by the cairo-rs VM.
  • cairo-rs-py: Bindings for using cairo-rs from Python code.

📚 Documentation

Cairo

Original Cairo VM Internals

We wrote a document explaining how the Cairo VM works. It can be found here.

Compilers and Interpreters

This is a list of recommended books to learn how to implement a compiler or an interpreter.

StarkNet

Computational Integrity and Zero Knowledge Proofs

Basics

ZK SNARKs

STARKs

Introduction:

Vitalik Buterin's blog series on zk-STARKs:

Alan Szepieniec's STARK tutorial:

StarkWare's STARK Math blog series:

⚖️ License

This project is licensed under the Apache 2.0 license.

See LICENSE for more information.