rules_cc_cross

Hermetic ARM/RISC-V/x86 cross-compiler toolchains for embedded Bazel builds (seL4, microkit, bare-metal).

bazel_dep(name = "rules_cc_cross", version = "0.1.0")

View source & releases on GitHub ↗

Hermetic ARM/RISC-V/x86 cross-compiler toolchains for embedded Bazel builds (seL4, microkit, bare-metal).

Status: v0.1.0

Implemented:

• aarch64-none-elf via the ARM GNU Toolchain (release 14.2.rel1).
• Hosts: macOS arm64, macOS x86_64, Linux x86_64, Linux aarch64.
• All tarballs verified against arm.com’s published sha256s.
• cc_toolchain_config with -ffreestanding -nostdlib defaults suitable for seL4 / microkit protection domains.
• One smoke example: examples/aarch64_hello.

Roadmap:

• 0.2.0 — riscv64-elf target (riscv-gnu-toolchain).
• 0.3.0 — x86_64-elf target.
• 0.4.0 — newlib-nano / picolibc selectors as feature toggles.

Install

.bazelrc:

common --registry=https://registry.fastverk.com/
common --registry=https://bcr.bazel.build/

MODULE.bazel:

bazel_dep(name = "rules_cc_cross", version = "0.1.0")

cc_cross = use_extension("@rules_cc_cross//cc_cross:extensions.bzl", "cc_cross")
cc_cross.toolchain(target = "aarch64-none-elf", version = "14.2.rel1")
use_repo(cc_cross, "arm_gnu_aarch64_none_elf")

register_toolchains("@arm_gnu_aarch64_none_elf//:all")

Use

Cross-compile any cc_binary for bare-metal aarch64:

platform(
    name = "aarch64_none_elf",
    constraint_values = [
        "@platforms//cpu:aarch64",
        "@platforms//os:none",
    ],
)

cc_binary(
    name = "my_pd",
    srcs = ["pd.c"],
    target_compatible_with = [
        "@platforms//cpu:aarch64",
        "@platforms//os:none",
    ],
)

bazel build //:my_pd --platforms=//:aarch64_none_elf

Layout

cc_cross/
├── extensions.bzl              # `cc_cross` module extension
├── defs.bzl                    # public rule re-exports
└── private/
    ├── arm_gnu_toolchain.bzl   # repo rule (download + materialize)
    ├── cc_toolchain_config.bzl # cc_toolchain_config rule
    ├── known_versions.bzl      # (version, host) -> sha256 map
    └── arm_gnu.BUILD.tpl       # BUILD.bazel template

Usage#

"""Smoke test: cross-compile a bare-metal aarch64 hello.

`bazel build //examples/aarch64_hello:hello --platforms=:aarch64_none_elf`
should produce an ELF that:

    file bazel-bin/examples/aarch64_hello/hello

reports as `ELF 64-bit LSB executable, ARM aarch64`.
"""

load("@platforms//host:constraints.bzl", "HOST_CONSTRAINTS")

package(default_visibility = ["//visibility:public"])

platform(
    name = "aarch64_none_elf",
    constraint_values = [
        "@platforms//cpu:aarch64",
        "@platforms//os:none",
    ],
)

cc_binary(
    name = "hello",
    srcs = ["hello.c"],
    # seL4-style: leave allocation, entry point, and the linker
    # script to the caller. This binary won't run on a real OS;
    # it's the cross-compile smoke test.
    linkopts = [
        "-Wl,--entry=_start",
        "-Wl,--no-warn-rwx-segments",
    ],
    target_compatible_with = [
        "@platforms//cpu:aarch64",
        "@platforms//os:none",
    ],
)

Conformance#

Dependencies#

Depends on

Versions#

1 published version, newest first. Each resolves to an immutable, integrity-checked archive.

Changelog#

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