download llvm from tarball's rather than shallow clone?

[nickdesaulniers]

Describe the bug
It looks like downloading llvm is done via git clone. Might be faster to download the tarball? I think https://github.com/llvm/llvm-project/tarball/master works.

To Reproduce
Steps to reproduce the behavior:

$ ./build-llvm.py --pgo kernel-defconfig --no-ccache

Expected behavior
Downloads faster.

Screenshots
If applicable, add screenshots to help explain your problem.

Environment (please complete the following information):

• Command you ran: ./build-llvm.py --pgo kernel-defconfig --no-ccache
• Distribution: gLinux (Debian
• Python version: Python 3.9.12
• Shell: zsh

[nathanchance]

It looks like downloading llvm is done via git clone.

Right, we do a full LLVM clone by default (not shallow) so that we can jump around in history if we need to as well as reducing bandwidth for updates.

Might be faster to download the tarball?

I guess it might be; I haven't tried to benchmark that. I suspect that it wouldn't be faster for updates though (over a shallow clone)?

By default, the script downloads its own copy of llvm-project. If you already have a copy that you would like to use, you can use the --llvm-folder option to tell build-llvm.py where it is and it will skip that entire block.