Hi @edford, I am experimenting with adding custom modifications to the default toolchain. I expect the local build of the apple-llvm toolchain to behave the same as the pre-built toolchain that’s included in Xcode. Right now there’s a difference between the two, and I am not sure whether I missed anything. So, Is there any difference between the toolchain on Apple’s Github and the one came with Xcode? Or is there anything specific that I have to pay attention to when I try to build the toolchain locally?