What changes has zapcc made to upstream llvm/clang?

[c0d3st0rm]

In an effort to better understand how zapcc is constructed, what changes (specifically, what elements and files of llvm/clang are modified) are made to enable zapcc's caching functionality (except for the addition of zapcc/zapccs in the tools directory)?

[yrnkrn]

There are many changes across the LLVM/clang codebase to enable caching and unloading.
diff LLVM r325000 and zapcc to see them.

[c0d3st0rm]

I tried that, and I got a multi-million line 100MB diff - is llvm-mirror/llvm@1a38f48 the correct commit? Is zapcc reformatted with clang-format or any similar tools, compared to the llvm repo?

[yrnkrn]

This looks like the right commit. Developing zapcc we were very careful to minimize the diff which was much smaller than 100MB, about 300KB if I recall correctly.

We were using the official (back then) subversion repository. It is now on https://github.com/llvm/llvm-project while https://github.com/llvm-mirror was set prior to LLVM moving to github. These do not explain a 100MB diff size.
Maybe directory structure or EOL are different?

[c0d3st0rm]

Directory structure looks to be the same, but I'll check the EOLs (although I'm not sure if those would affect a patch). I thought 100MB was a bit large. Did zapcc only touch llvm/clang, so I can ignore any other projects/libraries?

[yrnkrn]

Yes, only the LLVM and clang were modified.

[c0d3st0rm]

Even after a clang-format, I'm still seeing a 100MB diff - not sure what I'm doing wrong here.