Bazel C/C++ toolchain definitions for CloudABI cross compilation

This repository contains toolchain definitions for the Bazel build system to cross compile C/C++ code for CloudABI. Instead of relying on a toolchain that is provided by the host operating system, these rules automatically download development tools (e.g. Clang) and cross compile core C/C++ libraries (e.g., cloudlibc) during build. This has the following advantages:

• It allows you to develop CloudABI applications without making any system-level changes. There is no need to install anything on your system, apart from an officially released version of Bazel.
• The toolchain may be versioned as part of the project, making it easier to obtain reproducible build output.
• It makes it easier to test upcoming versions of individual components (e.g., Clang, libc++, cloudlibc).

Using these rules

Add the following code to your WORKSPACE file to declare the toolchain.

load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")

git_repository(
    name = "org_cloudabi_bazel_toolchains_cloudabi",
    # NOT VALID!  Replace this with a Git commit SHA.
    commit = "...",
    remote = "https://github.com/NuxiNL/bazel-toolchains-cloudabi.git",
)

load("@org_cloudabi_bazel_toolchains_cloudabi//:toolchains.bzl", "toolchains_cloudabi_dependencies")

toolchains_cloudabi_dependencies()

And add the following lines to .bazelrc to use the toolchain as part of builds. This file may be stored in the same directory as WORKSPACE.

build --cpu=x86_64-unknown-cloudabi
build --crosstool_top=@org_cloudabi_bazel_toolchains_cloudabi//:toolchain

Commands like bazel build and bazel test will now cross compile targets for CloudABI on x86-64.