How are prebuilts clang and sysroot built for host system?

[Biswa96]

Please let me know if there is any documentation about the aforementioned question.

[pirama-arumuga-nainar]

https://android.googlesource.com/toolchain/llvm_android/+/refs/heads/main/BUILD.md has instructions to bulid clang. The llvm-toolchain repo includes sysroots for the host (for windows and linux).

[Biswa96]

I am using exactly that repository. But it depends on prebuilts clang directory as mentioned here https://android.googlesource.com/toolchain/llvm_android/+/refs/heads/llvm-r522817/paths.py#42. I am asking about that clang toolchain.

[Biswa96]

I have figured out the following steps. Please correct me if I am wrong.

• have system-toolchain
• build stage1-llvm using system-toolchain
• build stage2-llvm using stage1-llvm

But I can not figure out how the sysroot was created at first place. I can not find any repository for the headers specifically.

[pirama-arumuga-nainar]

If you do repo init ... followed by reop sync like mentioned in BUILD.md, it should create the prebuilts/clang directory (and anything else necessary to run build.py).