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⚡ Cairo-vm ⚡

A faster and safer implementation of the Cairo VM in Rust

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Table of Contents

📖 About

Cairo VM is the virtual machine for the Cairo language.

Previously, there was a version of Cairo VM written in Python, which was used in production.

This repository contains the newer version, written in Rust. It's faster and has safer and more expressive typing. Now in production, it has replaced the older Python version to become the primary 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

These are needed in order to compile and use the project.

Optional

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

Installation script

You can install all of the required and optional dependencies by running the script install.sh while in the repository root.

Installing project dependencies

In order to compile programs you need to install the cairo-lang package.

Running the make deps (or the make deps-macos if you are runnning in MacOS) command will create a virtual environment with all the required dependencies.

You can then activate this environment by running

. cairo-vm-env/bin/activate

🚀 Usage

Adding cairo-vm as a dependency

You can add the following to your rust project's Cargo.toml:

cairo-vm = { version = '1.0.1'}

Running cairo-vm from CLI

To run programs from the command line, first compile the repository from the cairo-vm-cli folder:

cd cairo-vm-cli; cargo build --release; cd ..

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

In order to compile Cairo programs you need to activate the environment created while installing dependencies. To start it, run:

. cairo-vm-env/bin/activate

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-vm-cli cairo_programs/abs_value_array_compiled.json --layout all_cairo

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-vm.git

cd cairo-vm

cargo build --release

. cairo-vm-env/bin/activate

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

target/release/cairo-vm-cli cairo_programs/abs_value_array_compiled.json --layout all_cairo

Other CLI arguments

The cairo-vm-cli supports the following optional arguments:

For example, to obtain the air public inputs from a fibonacci program run, we can run :

  target/release/cairo-vm-cli cairo_programs/proof_programs/fibonacci.json --layout all_cairo --proof_mode --air_public_input fibonacci_public_input.json

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:

Running a function in a Cairo program with arguments

When running a Cairo program directly using the Cairo-vm 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 cairo_runner = CairoRunner::new(&program, LayoutName::all_cairo, false, 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(false)?;
cairo_runner.initialize_segments(None);

When using cairo-vm 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::from(2).into(),  //this is the entry point selector
                &MaybeRelocatable::from((2,0)).into() //this would be the output_ptr for example if our cairo function uses it
                ],
            false,
            &mut hint_processor,
        );

Running cairo 1 programs

To run a cairo 1 program enter in the folder cd cairo1-run and follow the cairo1-run documentation

WebAssembly Demo

A demo on how to use cairo-vm with WebAssembly can be found in examples/wasm-demo

Testing

To run the test suite you'll need cargo-llvm-cov dependency so make sure to run this command beforehand:

make deps

Now that you have the dependencies necessary to run the test suite you can run:

make test

Using a Dynamic Layout

A dynamic layout must be specified with a dynamic params file. You can find an example in: vm/src/tests/cairo_layout_params_file.json.

To run cairo 0 or 1 programs with a dynamic layout, you must use --layout dynamic and the --cairo_layout_params_file flag pointing a dynamic params file. For example, run:

cargo run --bin cairo-vm-cli cairo_programs/fibonacci.json --layout dynamic --cairo_layout_params_file vm/src/tests/cairo_layout_params_file.json

Tracer

Cairo-vm offers a tracer which gives you a visualization of how your memory and registers change line after line as the VM executes the code. You can read more about it here

📊 Benchmarks

Running a Cairo program that gets the 1.5 millionth Fibonacci number we got the following benchmarks:

Note before running the benchmark suite: the benchmark named iai_benchmark depends on Valgrind. Please make sure it is installed prior to running the iai_benchmark benchmark.

Run the complete benchmark suite with cargo:

cargo bench

Run only the criterion_benchmark benchmark suite with cargo:

cargo bench --bench criterion_benchmark

Run only the iai_benchmark benchmark suite with cargo:

cargo bench --bench iai_benchmark

Benchmark the cairo-vm in a hyper-threaded environment with the examples/hyper_threading/ crate

make hyper-threading-benchmarks

📜 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 feat/AmazingFeature)
  3. Commit your Changes (git commit -m 'feat: add some AmazingFeature')
  4. Push to the Branch (git push origin feat/AmazingFeature)
  5. Open a Pull Request

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

You can find more detailed instructions in the CONTRIBUTING.md document.

🌞 Related Projects

📚 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.