Fix and Arca

Fix is a prototype distributed operating system running on the Arca research kernel.

Build

Requires Linux x86-64 with x86-64-v3 and XSAVE, Bazelisk, GCC/G++, binutils, CMake, Make, Clang/libclang, clang-format, clang-tidy, Binaryen 120 (wasm-merge), Bash, GNU coreutils 9.3+, and Python 3. Set LIBCLANG_PATH or BINDGEN_EXTRA_CLANG_ARGS for nonstandard Clang installations.

git submodule update --init --recursive
bazel query //... --output=label_kind
bazel build //:artifacts
bazel test //:tests
bazel test //tests:format //tests:lint
bazel run //:format
bazel run //programs/kernel:hello -- Ada
bazel run //programs/arca:add -- tuple:word:2,word:3
bazel run //fix -- init /path/to/seed.tar --precompile
bazel run //programs/fix:addblob -- 2u64 3u64
bazel run //fix -- run path/to/program.fix

Arca arguments: word:, blob:, tuple: (comma-separated), elf:<path>, null. Fix arguments are Fix expressions. _elf targets expose raw artifacts. The map and curry combinators provide only _elf targets. Test fixtures live under //tests; SIMD and combinator tests run with bazel test //arca/kernel:tests. Integration tests for standalone programs can live beside those programs.

Arca and Fix unit tests use Rust's host libtest runner with a fresh VM per case. List cases with bazel test //fix/runtime:tests --test_arg=--list --test_output=all, or select them with bazel test //fix/runtime:tests --test_filter=continuations. Fixtures are loaded from Bazel runfiles rather than embedded in test images.

Use --config=release for optimized builds.

Userspace targets x86_64-unknown-arca with the x86-64-v3 baseline and System V calling conventions. Bazel builds core, alloc, and compiler_builtins from sources matching the pinned Rust compiler. The kernel uses x86_64-unknown-none with its soft-float ABI.

The optional bootstrap process builds self-hosted Wasm-to-ELF toolchains from pinned sources and checks byte-identical generations. Shared caches use ordinary Bazel configuration.

Benchmarks

Microbenchmarks cover Arca lifecycle and continuation operations, Fix invocation, and resident, copied, and persisted continuations. Run bazel run --config=release //:benchmarks for all numeric benchmark results, or select a leaf suite such as //fix/benchmarks:continuations.

Formatting

Format Rust throughout the codebase and C SDK sources:

bazel run //:format

Language servers

Generate compile_commands.json for clangd and rust-project.json for rust-analyzer:

bazel run //:lsp

Environment-dependent tests

bazel test //:tests requires /dev/kvm; without it, use bazel test //:host_tests. The optional proof test requires opam, Python 3.11+, and the native build prerequisites listed in fix/proof/README.md. Bazel provisions its own pinned OCaml/Rocq toolchain on the first run:

bazel test //fix/proof:check

Bazel compiles each module and caches its kernel check separately. The proof embeds the Wasm binary built from fix/proof/collector/collector.wat and verifies the installed library dependencies. Individual module checks assume their imports; the full suite verifies the complete dependency closure. CI runs it separately from the default tests. Theory directories declare their Bazel module dependencies and Rocq namespaces.

The Fix CLI also provides persistent object construction, reading, inspection, and labels.

Licensed under LGPL-2.1-or-later.