Bazel zig cc toolchain

This is an early stage zig-cc toolchain that can cross-compile cgo programs to these os/archs:

• amd64-linux-gnu.2.19
• amd64-linux-musl
• arm64-linux-gnu.2.28
• arm64-linux-musl
• amd64-macos
• arm64-macos

Usage

Add this to your WORKSPACE:

BAZEL_ZIG_CC_VERSION = "0.2"

http_archive(
    name = "bazel-zig-cc",
    sha256 = "0af0493e2d4822a94803e8a83703d25e0f9d8fe6ec4daf3b0ed3ca4cd6076650",
    strip_prefix = "bazel-zig-cc-{}".format(BAZEL_ZIG_CC_VERSION),
    urls = ["https://git.sr.ht/~motiejus/bazel-zig-cc/archive/{}.tar.gz".format(BAZEL_ZIG_CC_VERSION)],
)

load("@bazel-zig-cc//toolchain:defs.bzl", zig_register_toolchains = "register_toolchains")

zig_register_toolchains()

This will register the "default" toolchains. Look into register_toolchains on which parameters it accepts.

Testing

linux cgo + glibc 2.19

$ bazel build --platforms @io_bazel_rules_go//go/toolchain:linux_amd64_cgo //test:hello
$ file bazel-out/k8-fastbuild-ST-d17813c235ce/bin/test/hello_/hello
bazel-out/k8-fastbuild-ST-d17813c235ce/bin/test/hello_/hello: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.0.0, Go BuildID=redacted, with debug_info, not stripped

linux cgo + musl

$ bazel build \
    --platforms @io_bazel_rules_go//go/toolchain:linux_amd64_cgo \
    --extra_toolchains @zig_sdk//:x86_64-linux-musl_toolchain //test:hello
...
$ file ../bazel-out/k8-fastbuild-ST-d17813c235ce/bin/test/hello_/hello
../bazel-out/k8-fastbuild-ST-d17813c235ce/bin/test/hello_/hello: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, Go BuildID=redacted, with debug_info, not stripped
$ ../bazel-out/k8-fastbuild-ST-d17813c235ce/bin/test/hello_/hello
hello, world

macos cgo

$ bazel build --platforms @io_bazel_rules_go//go/toolchain:darwin_amd64_cgo //test:gognu
...
$ file bazel-bin/test/gognu_/gognu
bazel-bin/test/gognu_/gognu: Mach-O 64-bit x86_64 executable, flags:<NOUNDEFS|DYLDLINK|TWOLEVEL|PIE>

Transient docker environment

$ docker run -e CC=/usr/bin/false -ti --rm -v $(pwd):/x -w /x debian:buster-slim
# apt update && apt install wget git -y
# . .envrc

And run the bazel build commands above. Take a look at .build.yml and see how CI does it.

Known Issues

• ziglang/zig #9485 glibc 2.27 or older: fcntl64 not found, but zig's glibc headers refer it
• ziglang/zig #9431 FileNotFound when compiling macos
• rules/go #2894 Per-arch_target linker flags

Closed issues:

• ziglang/zig #9139 zig c++ hanging when compiling in parallel (CLOSED)
• golang/go #46644 cmd/link: with CC=zig: SIGSERV when cross-compiling to darwin/amd64 (CLOSED)
• ziglang/zig #9050 golang linker segfault (CLOSED)
• ziglang/zig #7917 [meta] better c/c++ toolchain compatibility (CLOSED)
• ziglang/zig #7915 ar-compatible command for zig cc (CLOSED)