An upstream Clang/LLVM-based toolchain for contemporary C++ and heterogeneous programming.

This project interleaves Nix and Bazel with opinionated Starlark rules for C++. Purpose-built for the bleeding edge. Reproducible and hermetic beyond Bazel's dependency graph.

1. Install the nix package manager and enable flakes.

2. Create a rules_ll compatible workspace. To keep the development shell in sync with the rules_ll Bazel module, pin the flake to a specific version:

   git init
   nix flake init -t github:eomii/rules_ll/<version>

   The default toolchains include C++ and HIP for AMDGPU. If you also want to target NVPTX devices (Nvidia GPUs), make sure to read the CUDA license and set unfree = true in flake.nix.

   See tags to find the most recent version.

3. Enter the rules_ll development shell:

   nix develop

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Use the interfaces and exposed_interfaces attributes to build C++ modules. C++ modules guide.

load(
    "@rules_ll//ll:defs.bzl",
    "ll_binary",
    "ll_library",
)

ll_library(
    name = "mymodule",
    srcs = ["mymodule_impl.cpp"],
    exposed_interfaces = {
        "mymodule_interface.cppm": "mymodule",
    },
    compile_flags = ["-std=c++20"],
)

ll_binary(
    name = "main",
    srcs = ["main.cpp"],
    deps = [":mymodule"],
)

Build compilation databases to use Clang-Tidy as part of your workflows and CI pipelines. Clang-Tidy guide.

load(
   "@rules_ll//ll:defs.bzl",
   "ll_compilation_database",
)

filegroup(
    name = "clang_tidy_config",
    srcs = [".clang-tidy"],
)

ll_compilation_database(
   name = "compile_commands",
   targets = [
      ":my_very_tidy_target",
   ],
   config = ":clang_tidy_config",
)

Integrate sanitizers in your builds with the sanitize attribute. Sanitizers guide.

load(
    "@rules_ll//ll:defs.bzl",
    "ll_binary",
)

ll_binary(
    name = "sanitizer_example",
    srcs = ["totally_didnt_shoot_myself_in_the_foot.cpp"],
    sanitize = ["address"],
)

Use CUDA and HIP without any manual setup. CUDA and HIP guide.

load(
    "@rules_ll//ll:defs.bzl",
    "ll_binary",
)

ll_binary(
    name = "cuda_example",
    srcs = ["look_mum_no_cuda_setup.cu"],
    compilation_mode = "cuda_nvptx",  # Or "hip_nvptx". Or "hip_amdgpu".
    compile_flags = [
        "--std=c++20",
        "--offload-arch=sm_70",  # Your GPU model.
    ],
)

Licensed under the Apache 2.0 License with LLVM exceptions.

This repository uses overlays and automated setups for the CUDA toolkit and HIP. Using compilation_mode for heterogeneous toolchains implies acceptance of their licenses.