This repository contains the PureDarwin build automation system. It's essentially a simpler version of darwinbuild that uses modern concepts and best practices.

Currently, this project contains two scripts: setup.sh and rc, both written as standard UNIX shell scripts. The setup.sh scripts is meant to be executed in the user's shell (usually with the source builtin), and has been tested in both bash and zsh. The setup.sh script sets up the user's build environment for building PureDarwin, and installs the rc script into the user's PATH (which is updated to include the ${RC_HOST_BIN} directory).

The rc script is used to invoke PureDarwin toolchain and system builds. It uses the provided command line arguments and the environment variables set by the setup.sh script or manually by the user to configure, build, and install all components of the PureDarwin distribution. The available options and environment are described below.

To get started quickly with the default configuration, navigate to the PureDarwin repository root, ensure you've cloned this submodule properly, and execute source tools/dbuild/setup.sh. Some default build variables should be output. You can now run rc or rc root from anywhere to return to the PureDarwin root directory.

Now, to build the host toolchain, run rc --make-host-toolchain (this will take many minutes, even on the best machine).

And finally, run rc build. This should invoke a full system build. The built products will be installed to the ${RC_SYSTEM_ROOT} directory.

Similarly to Apple's internal build system, the Darwin build system uses various environment variables with the RC_* prefix. I document some of these here:

• RC_HOST_ARCH: The architecture of the host machine
• RC_HOST_TYPE: The name of the host environment (currently, Darwin or Linux)
• RC_DARWIN_ROOT: The path of root of the PureDarwin repository.
• RC_BUILD_ROOT: The directory in which to place temporary build files.
• RC_SOURCE_DIR: The directory where system sources live.
• RC_PRODUCT_DIR: The directory in which to place build products (host tools, system root directory, etc.)
• RC_SYSTEM_ROOT: The directory in which to place the built system.
• RC_TOOLS_DIR: The directory where host tool sources live (we live here)
• RC_HOST_BIN: The directory where toolchain binaries should be placed
• RC_BUILD_JOBS: The number of concurrent threads to build with.
• RC_VERBOSE: Tell the build system to output more messages.

Currently, the following options are supported for the rc command:

• --force-rebuild-llvm: Rebuild host compiler + LLVM-related tools
• --make-host-toolchain: Build the host toolchain
• build: Build the target system
• root: Navigate to the PureDarwin root directory.

• Why is this repository called dbuild?
• Allow for building LLVM/ninja/tools without git checkout
• Figure out how best to use/set RC_NONARCH_CFLAGS/RC_NONARCH_CXXFLAGS (this really shouldn't be managed by rc)
• Support more architectures (I have an M1 mac, I can hopefully do this)
• Generate a system ISO? (This is more of a long-term goal)
• rc clean {,build,tools,all}