A couple weeks ago Apple finally released the XNU source code for macOS Catalina. It looks like they have now added more of the open source packages needed to build the entire XNU kernel, so it’s time to update my build instructions.
If you’re interested in looking through what’s new or changed in the latest XNU code, you can look at a diff of the latest source here:
https://github.com/knightsc/darwin-xnu/commit/21722f3926534b9dab63b1194b0136ddd6d1fc24
The first issue that I ran into was compilation issues with dtrace-338.0.1. It looks like Apple is now including a handful of llvm header files as part of dtrace in the include subfolder. One of those files include/llvm-Support/PointerLikeTypeTraits.h still references a file from the llvmCore folder structure. So in order to get the dtrace tools to compile I had to generate the missing DataTypes.h file and update PointerLikeTypeTraits.h to reference it.
With this dtrace header fix in place the build script will run through and generate all of the depedencies needed to try to compile the kernel. Unfortunately it looks like there are some errors compiling the kernel itself that I’m still looking into.
For now if you want to follow along at home, here’s a bash script to automate the entire process of building a DEBUG kernel. (Note: It pulls the fixed dtrace header files from gists I’ve created.):