How to choose the correct AOSP clang release for building Android kernel 4.19.xxx

[Amani Gall]

I am trying to build a custom kernel 4.19.xxx for my device running Android 14. I’m wondering what criteria determine the appropriate release of AOSP Clang to use. Is it based on the kernel version, the Android version, or both?
On the AOSP prebuilts page, clang-r530567 is listed as the current version for the Android Platform. However, for the Android Linux kernel, clang-r522817 is specified as the current version. Meanwhile, the mainline build configs reference clang-r536225

[Nick Desaulniers]

On Fri, Feb 7, 2025 at 7:20 AM Amani Gall <amanir...@gmail.com> wrote:
>
>
> I am trying to build a custom kernel 4.19.xxx for my device running Android 14. I’m wondering what criteria determine the appropriate release of AOSP Clang to use. Is it based on the kernel version, the Android version, or both?

Both; we stabilize a final release of LLVM for a given Android
release. Then the compiler gets frozen for that kernel image, due to
GKI.

> On the AOSP prebuilts page, clang-r530567 is listed as the current version for the Android Platform. However, for the Android Linux kernel, clang-r522817 is specified as the current version. Meanwhile, the mainline build configs reference clang-r536225

Yeah, at some point we moved the compiler version to that
build.config.constants file you found. Back in 4.19, it was just
specified in build.config.common.

I think https://android.googlesource.com/kernel/common/+/refs/heads/android-4.19-stable/build.config.common#6
is what you're looking for?

You should also be able to build with newer versions of llvm, such as
top of tree.
--
Thanks,
~Nick Desaulniers