Swiftana: Swift on Solana

Write Solana BPF programs in Swift using upstream Rust toolchain, LLVM, and sbpf-linker.

Highlights

• End-to-end Swift to BPF compilation pipeline driven with upstream toolings
• Custom LLVM pass to adapt Swift calling conventions and normalizes Swift literals
• Rust integration tests exercise the program under Mollusk SVM
• Direct Solana syscalls by hash with zero Solana SDK dependencies

Quickstart

1. Ensure prerequisites are installed (see below).
2. make build to emit LLVM IR, retarget for BPF, and link build/program.so.
3. make test to rebuild and run the Rust integration suite against Mollusk.
4. Inspect generated IR or artifacts under build/ as needed for debugging.

Prerequisites

The toolchain expects a recent Swift compiler plus LLVM utilities (opt, llvm-as, llvm-config, clang++) and sbpf-linker.

# Fedora / RHEL example
sudo dnf install swift-lang llvm llvm-devel clang
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
cargo install sbpf-linker


# macOS example
brew install swift llvm
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
cargo install sbpf-linker

Ensure llvm-config is on PATH; override with LLVM_CONFIG=/path/to/bin/llvm-config if necessary. The build also uses clang++ to compile the custom LLVM pass.

Build Pipeline

1. swiftc emits optimized LLVM IR (build/entrypoint.ll) for src/entrypoint.swift.
2. The pass in tooling/llvm/swift_bpf_prepare_pass.cpp is built and run to pin literals and reset Swift calling conventions.
3. opt -mtriple=bpfel retargets the module for the Solana BPF ABI and llvm-as produces bitcode.
4. sbpf-linker --cpu v3 links the bitcode into build/program.so, suitable for deployment.

Build

make

Testing

make test

Note

This will build the program first. To only run tests, use cargo test.

Troubleshooting

• Install matching Swift and LLVM versions; stale toolchains often fail during IR emission
• If sbpf-linker cannot find LLVM libs, export LLVM_LIBDIR=/path/to/llvm/lib
• Re-run make clean when switching Swift toolchains to avoid stale IR
• Pass SWIFTC=/custom/swiftc or OPT=/custom/opt to make when using non-default binaries