Bazel Apple toolchain for non-Apple platforms

This repository contains toolchain configuration rules for Bazel that can be used to build apps and frameworks for Apple platforms from non-Apple platforms. Current supported host is x86_64 Linux only. Requires Bazel 9+.

Setup

1. Add the dependency to your MODULE.bazel:

   bazel_dep(name = "rules_applecross", version = "0.0.3")
   git_override(
       module_name = "rules_applecross",
       remote = "https://github.com/apple-cross-toolchain/rules_applecross.git",
       commit = "<commit>",
   )

2. Configure the toolchain in MODULE.bazel:

   apple_cross_toolchain = use_extension(
       "@rules_applecross//toolchain:extensions.bzl",
       "apple_cross_toolchain",
   )
   apple_cross_toolchain.configure(
       name = "apple_cross_toolchain",
       apple_sdk_urls = ["<url-to-apple-sdk-archive>"],
       apple_sdk_archive_type = "tar.xz",  # if not inferrable from URL
   )
   use_repo(apple_cross_toolchain, "apple_cross_toolchain")
   
   register_toolchains("@apple_cross_toolchain//:cc-toolchain-ios_x86_64")
   register_toolchains("@apple_cross_toolchain//:cc-toolchain-ios_arm64")
   register_toolchains("@apple_cross_toolchain//:swift-toolchain-ios_x86_64")
   register_toolchains("@apple_cross_toolchain//:swift-toolchain-ios_arm64")
   # ... add more platforms as needed (darwin, tvos, watchos)

3. Add the following to your .bazelrc:

   build --xcode_version_config=@rules_applecross//xcode_config:host_xcodes
   build --action_env=DEVELOPER_DIR=external/rules_applecross++apple_cross_toolchain+apple_cross_toolchain/Xcode.app/Contents/Developer
   build --@build_bazel_rules_apple//apple:sdk_tool_files=@apple_cross_toolchain//:sdk_tool_files
   

4. Build an example:

   bazel build @rules_applecross//examples/ios/HelloWorldSwiftUI:HelloWorld
   

Notes

• Apple SDKs archives are not publicly available. If you have access to macOS, you can build one yourself by running tools/package-sdks.sh.

Remote Build Execution Setup (for BuildBuddy)

1. Define a platform target; for example, in platforms/BUILD:

   platform(
       name = "docker_image_platform",
       constraint_values = [
           "@platforms//cpu:x86_64",
           "@platforms//os:linux",
       ],
       exec_properties = {
           "OSFamily": "Linux",
           "container-image": "<your-docker-image>",
       },
   )

2. Add the following to your .bazelrc:

   build:remote --bes_backend=grpcs://cloud.buildbuddy.io
   build:remote --bes_results_url=https://app.buildbuddy.io/invocation/
   build:remote --jobs=100
   build:remote --remote_download_toplevel
   build:remote --remote_executor=grpcs://cloud.buildbuddy.io
   build:remote --remote_timeout=3600
   build:remote --strategy=SwiftCompile=remote,sandboxed,worker,local
   build:remote --tls_client_certificate=buildbuddy-cert.pem
   build:remote --tls_client_key=buildbuddy-key.pem
   

3. Build with --config=remote:

   bazel build --config=remote @rules_applecross//examples/ios/HelloWorldSwiftUI:HelloWorld