agoessling / bazel_bootlin

Hermetic C/C++ toolchains for Bazel

bazel_bootlin

Provides hermetic Bazel C/C++ toolchains based on Buildroot toolchains provided by Bootlin.

Usage

WORKSPACE

To incorporate bazel_bootlin toolchains into your project, copy the following into your WORKSPACE file.

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "bazel_bootlin",
    # See release page for latest version url and sha.
)

load("@bazel_bootlin//toolchains:toolchains.bzl", "bootlin_all_toolchain_deps")

bootlin_all_toolchain_deps()

This will bring all of the available toolchains (and their associated platform definitions) into your project. The toolchains will only be downloaded when actually utilized, but if you prefer, you can only import a specific toolchain:

load("@bazel_bootlin//toolchains:toolchains.bzl", "bootlin_toolchain_deps")

bootlin_toolchain_deps(
    architecture = "x86-64-core-i7",
    cstdlib = "glibc",
    buildroot_version = "2020.08-1",
)

• architecture - refers to the architecture string used by Bootlin.
• cstdlib - refers to the cstdlib string used by bootlin.
• buildroot_version - refers to the Buildroot version string used by Bootlin.

Available Toolchains

Currently bazel_bootlin only provides the "glibc--stable" version of the following Bootlin toolchains:

Architecture	cstdlib	Buildroot Version
x86-64	glibc	2022.08-1, 2021.11-5
x86-64-core-i7	glibc	2020.08-1
aarch64	glibc, musl	2021.11-1, 2020.08-1
armv7-eabihf	glibc	2020.08-1
riscv64-lp64d	glibc	2024.02-1

This list is easily expanded. If a toolchain of interest isn't available feel free to submit and issue, or alternatively take a look at _AVAILABLE_TOOLCHAINS in setup_toolchains.py and create a pull request. Don't forget to actually run setup_toolchains.py after adding a toolchain and before submitting a PR:

bazel run //:setup_toolchains

Platforms

bazel_bootlin defines a different platform for each toolchain that is included. The platforms specify constraint_value for the canonical @platforms//os:os and @platforms//cpu:cpu constraint_setting:

platform(
    name = "{architecture}-linux-{cstdlib}-{buildroot_version}",
    constraint_values = [
        "@platforms//cpu:{architecture}",
        "@platforms//os:linux",
        "@bazel_bootlin//platforms:{buildroot_version}",
    ],
)

Specifying one of these platforms will cause Bazel to use the corresponding toolchain during build.

Building With Toolchain

In order to enable toolchain selection via platforms, Bazel requires a special flag along with the target platform:

bazel build --incompatible_enable_cc_toolchain_resolution --platforms=@bazel_bootlin//platforms:{architecture}-linux-{cstdlib}-{buildroot_version} //...

The ergonomics can be improved by placing the flags in a .bazelrc file:

build --incompatible_enable_cc_toolchain_resolution
build --platforms=@bazel_bootlin//platforms:{architecture}-linux-{cstdlib}-{buildroot_version}

Then a simple bazel build //... will utilize the desired toolchain.

bazel_bootlin's Issues

MAC OS support

Hello,
Thanks for this great repo!

In any case, do you have any plan to support mac os with Apple silicon chip?
Also, I am wondering if I can build a target for linux machine deployment on Mac OS host.

Thanks in advance.

aarch64 doesn't use hermetic toolchain

I did a fresh checkout of the repo and on aarch64 It looks like /usr/bin/gcc is used instead of the gcc wrapper.

uname -a
Linux aarch64 5.15.49-linuxkit-pr #1 SMP PREEMPT Thu May 25 07:27:39 UTC 2023 aarch64 aarch64 aarch64 GNU/Linux
bazel --version
bazel 6.3.2

bazel build //... -s --platforms=@bazel_bootlin//platforms:aarch64-linux-gnu-2021.11-1
SUBCOMMAND: # //test:test_c [action 'Compiling test/test_c.c', configuration: 95105f2896e296b36620e135202c42732efc426859ef352e00c38145703cde07, execution platform: @local_config_platform//:host]
(cd /home/vscode/.cache/bazel/_bazel_vscode/1b5ddfc1c5d8e8325371095e85f8fe98/execroot/bazel_bootlin && \
  exec env - \
    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
    PWD=/proc/self/cwd \
  /usr/bin/gcc -U_FORTIFY_SOURCE -fstack-protector -Wall -Wunused-but-set-parameter -Wno-free-nonheap-object -fno-omit-frame-pointer -MD -MF bazel-out/aarch64-fastbuild/bin/test/_objs/test_c/test_c.pic.d '-frandom-seed=bazel-out/aarch64-fastbuild/bin/test/_objs/test_c/test_c.pic.o' -fPIC '-DBAZEL_CURRENT_REPOSITORY=""' -iquote . -iquote bazel-out/aarch64-fastbuild/bin -iquote external/bazel_tools -iquote bazel-out/aarch64-fastbuild/bin/external/bazel_tools -fno-canonical-system-headers -Wno-builtin-macro-redefined '-D__DATE__="redacted"' '-D__TIMESTAMP__="redacted"' '-D__TIME__="redacted"' -c test/test_c.c -o bazel-out/aarch64-fastbuild/bin/test/_objs/test_c/test_c.pic.o)
# Configuration: 95105f2896e296b36620e135202c42732efc426859ef352e00c38145703cde07
# Execution platform: @local_config_platform//:host
SUBCOMMAND: # //test:test_cpp [action 'Compiling test/test_cpp.cc', configuration: 95105f2896e296b36620e135202c42732efc426859ef352e00c38145703cde07, execution platform: @local_config_platform//:host]
(cd /home/vscode/.cache/bazel/_bazel_vscode/1b5ddfc1c5d8e8325371095e85f8fe98/execroot/bazel_bootlin && \
  exec env - \
    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
    PWD=/proc/self/cwd \
  /usr/bin/gcc -U_FORTIFY_SOURCE -fstack-protector -Wall -Wunused-but-set-parameter -Wno-free-nonheap-object -fno-omit-frame-pointer '-std=c++0x' -MD -MF bazel-out/aarch64-fastbuild/bin/test/_objs/test_cpp/test_cpp.pic.d '-frandom-seed=bazel-out/aarch64-fastbuild/bin/test/_objs/test_cpp/test_cpp.pic.o' -fPIC '-DBAZEL_CURRENT_REPOSITORY=""' -iquote . -iquote bazel-out/aarch64-fastbuild/bin -iquote external/bazel_tools -iquote bazel-out/aarch64-fastbuild/bin/external/bazel_tools -fno-canonical-system-headers -Wno-builtin-macro-redefined '-D__DATE__="redacted"' '-D__TIMESTAMP__="redacted"' '-D__TIME__="redacted"' -c test/test_cpp.cc -o bazel-out/aarch64-fastbuild/bin/test/_objs/test_cpp/test_cpp.pic.o)
# Configuration: 95105f2896e296b36620e135202c42732efc426859ef352e00c38145703cde07
# Execution platform: @local_config_platform//:host
SUBCOMMAND: # //test:test_c [action 'Linking test/test_c', configuration: 95105f2896e296b36620e135202c42732efc426859ef352e00c38145703cde07, execution platform: @local_config_platform//:host]
(cd /home/vscode/.cache/bazel/_bazel_vscode/1b5ddfc1c5d8e8325371095e85f8fe98/execroot/bazel_bootlin && \
  exec env - \
    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
    PWD=/proc/self/cwd \
  /usr/bin/gcc @bazel-out/aarch64-fastbuild/bin/test/test_c-2.params)
# Configuration: 95105f2896e296b36620e135202c42732efc426859ef352e00c38145703cde07
# Execution platform: @local_config_platform//:host
SUBCOMMAND: # //test:test_cpp [action 'Linking test/test_cpp', configuration: 95105f2896e296b36620e135202c42732efc426859ef352e00c38145703cde07, execution platform: @local_config_platform//:host]
(cd /home/vscode/.cache/bazel/_bazel_vscode/1b5ddfc1c5d8e8325371095e85f8fe98/execroot/bazel_bootlin && \
  exec env - \
    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
    PWD=/proc/self/cwd \
  /usr/bin/gcc @bazel-out/aarch64-fastbuild/bin/test/test_cpp-2.params)
# Configuration: 95105f2896e296b36620e135202c42732efc426859ef352e00c38145703cde07
# Execution platform: @local_config_platform//:host
INFO: Elapsed time: 10.369s, Critical Path: 1.28s
INFO: 15 processes: 11 internal, 4 processwrapper-sandbox.
INFO: Build completed successfully, 15 total actions

Here is the output from x64 ubuntu:

uname -a
Linux x86 5.15.49-linuxkit-pr #1 SMP PREEMPT Thu May 25 07:27:39 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

bazel --version
bazel 6.3.2

bazel build //... -s --platforms=@bazel_bootlin//platforms:x86-64-linux-gnu-2022.08-1
SUBCOMMAND: # //test:test_cpp [action 'Compiling test/test_cpp.cc', configuration: 4dff85ffdc8e7302948846e7d4e1db364902c5cc05c8d89536748cd758395c6c, execution platform: @local_config_platform//:host]
(cd /home/vscode/.cache/bazel/_bazel_vscode/1b5ddfc1c5d8e8325371095e85f8fe98/execroot/bazel_bootlin && \
  exec env - \
    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
    PWD=/proc/self/cwd \
  toolchains/tool_wrappers/x86-64/2022.08-1/x86-64-linux-gnu-2022.08-1-gcc -MD -MF bazel-out/k8-fastbuild/bin/test/_objs/test_cpp/test_cpp.pic.d '-frandom-seed=bazel-out/k8-fastbuild/bin/test/_objs/test_cpp/test_cpp.pic.o' -fPIC '-DBAZEL_CURRENT_REPOSITORY=""' -iquote . -iquote bazel-out/k8-fastbuild/bin -iquote external/bazel_tools -iquote bazel-out/k8-fastbuild/bin/external/bazel_tools -U_FORTIFY_SOURCE -fstack-protector -Wall -Wunused-but-set-parameter -Wno-free-nonheap-object -fno-omit-frame-pointer -fdiagnostics-color -no-canonical-prefixes -fno-canonical-system-headers '--sysroot=external/x86-64-linux-gnu-2022.08-1/x86_64-buildroot-linux-gnu/sysroot' -Wno-builtin-macro-redefined '-D__DATE__="redacted"' '-D__TIMESTAMP__="redacted"' '-D__TIME__="redacted"' '-std=c++17' -c test/test_cpp.cc -o bazel-out/k8-fastbuild/bin/test/_objs/test_cpp/test_cpp.pic.o)
# Configuration: 4dff85ffdc8e7302948846e7d4e1db364902c5cc05c8d89536748cd758395c6c
# Execution platform: @local_config_platform//:host
SUBCOMMAND: # //test:test_c [action 'Compiling test/test_c.c', configuration: 4dff85ffdc8e7302948846e7d4e1db364902c5cc05c8d89536748cd758395c6c, execution platform: @local_config_platform//:host]
(cd /home/vscode/.cache/bazel/_bazel_vscode/1b5ddfc1c5d8e8325371095e85f8fe98/execroot/bazel_bootlin && \
  exec env - \
    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
    PWD=/proc/self/cwd \
  toolchains/tool_wrappers/x86-64/2022.08-1/x86-64-linux-gnu-2022.08-1-gcc -MD -MF bazel-out/k8-fastbuild/bin/test/_objs/test_c/test_c.pic.d '-frandom-seed=bazel-out/k8-fastbuild/bin/test/_objs/test_c/test_c.pic.o' -fPIC '-DBAZEL_CURRENT_REPOSITORY=""' -iquote . -iquote bazel-out/k8-fastbuild/bin -iquote external/bazel_tools -iquote bazel-out/k8-fastbuild/bin/external/bazel_tools -U_FORTIFY_SOURCE -fstack-protector -Wall -Wunused-but-set-parameter -Wno-free-nonheap-object -fno-omit-frame-pointer -fdiagnostics-color -no-canonical-prefixes -fno-canonical-system-headers '--sysroot=external/x86-64-linux-gnu-2022.08-1/x86_64-buildroot-linux-gnu/sysroot' -Wno-builtin-macro-redefined '-D__DATE__="redacted"' '-D__TIMESTAMP__="redacted"' '-D__TIME__="redacted"' -c test/test_c.c -o bazel-out/k8-fastbuild/bin/test/_objs/test_c/test_c.pic.o)
# Configuration: 4dff85ffdc8e7302948846e7d4e1db364902c5cc05c8d89536748cd758395c6c
# Execution platform: @local_config_platform//:host
ERROR: /home/vscode/bazel_bootlin/test/BUILD:7:8: Compiling test/test_c.c failed: undeclared inclusion(s) in rule '//test:test_c':
this rule is missing dependency declarations for the following files included by 'test/test_c.c':
  '/proc/self/cwd/external/x86-64-linux-gnu-2022.08-1/lib/gcc/x86_64-buildroot-linux-gnu/11.3.0/include/stddef.h'
  '/proc/self/cwd/external/x86-64-linux-gnu-2022.08-1/lib/gcc/x86_64-buildroot-linux-gnu/11.3.0/include/stdarg.h'
INFO: Elapsed time: 13.111s, Critical Path: 4.29s
INFO: 3 processes: 3 internal.
FAILED: Build did NOT complete successfully

It's using the gcc from toolchain but for some reason it doesn't find these headers. I might have closed out this too soon: #5

execvp fails for x86-64-linux-gnu-2022.08-1

Hi, I'm trying to setup this toolchain and for some reason it works for aarch64 but not x86-64:

failed: (Exit 1): x86-64-linux-gnu-2022.08-1-gcc failed: error executing command (from target //common:hex_dump) external/bazel_bootlin/toolchains/tool_wrappers/x86-64/2022.08-1/x86-64-linux-gnu-2022.08-1-gcc -MD -MF bazel-out/k8-fastbuild/bin/common/_objs/hex_dump/hex_dump.pic.d ... (remaining 40 arguments skipped)

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
src/main/tools/process-wrapper-legacy.cc:80: "execvp(external/bazel_bootlin/toolchains/tool_wrappers/x86-64/2022.08-1/x86-64-linux-gnu-2022.08-1-gcc, ...)": No such file or directory

Here is the WORKSPACE file:

git_repository(
    name = "bazel_bootlin",
    remote = "https://github.com/agoessling/bazel_bootlin",
    commit = "b65607ab1418b102ffc4a7113996c26c581a8e78",
)

load("@bazel_bootlin//toolchains:toolchains.bzl", "bootlin_all_toolchain_deps")

bootlin_all_toolchain_deps()

.bazelrc
build --incompatible_enable_cc_toolchain_resolution

invoked with:
bazel build //... --platforms=@bazel_bootlin//platforms:x86-64-linux-gnu-2022.08-1
and
bazel build //... --platforms=@bazel_bootlin//platforms:aarch64-linux-gnu-2021.11-1

Is there anything I missed?
Thanks