[READY] Use the archive with precompiled binaries for updating the resource dir

[bstaletic]

While most headers in the resource directory are present in the clang source archive, some are generated during compiling.

As a bonus, non-header files do not exist in the resource directory, in the archives containing binaries. Previously we have manually removed a CMakeLists.txt, but have been leaving behind some READMEs.

HLSL headers are not installed, because the feature is highly experimental.
openmp_wrappers/{stdlib.h,time.h} are not intended to be included in resource directory.

Closes #1740

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This change is 

[bstaletic]

Here's when and why the change to clang resource directory was introduced.
llvm/llvm-project@c17d9b4

In short, ARM intrinsics are 1MB and RISC-V are 10MB.

Now I wonder if we should commit these headers or maybe package them with clangd and libclang and have them only be available if user enables clangd/libclang completer.
I'm definitely leaning towards making these things optional.

Additional benefit of that approach would be always using the resource dir that comes from the same archive as clangd and libclang.

Reviewable status: 0 of 2 LGTMs obtained

[codecov]

Codecov Report

Merging #1741 (60d43a5) into master (da9c643) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

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##           master    #1741   +/-   ##
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  Coverage   95.85%   95.85%           
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  Files          84       84           
  Lines        8318     8318           
  Branches      163      163           
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  Hits         7973     7973           
  Misses        295      295           
  Partials       50       50           

[puremourning]

Reviewable status: 0 of 2 LGTMs obtained (waiting on @bstaletic)

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update_clang_headers.py line 69 at r1 (raw file):

def UpdateClangHeaders( version, temp_dir ):
  # The headers do not seem to differ between archives, so pick the smallest
  archive_name = 'clang+llvm-18.1.1-arm64-apple-darwin.tar.xz'

Don’t hard-code version?

[puremourning]

Reviewed 16 of 16 files at r1, all commit messages.
Reviewable status: 0 of 2 LGTMs obtained (waiting on @bstaletic)

[bstaletic]

Assuing the CI passes, this is ready.

Not vendoring the headers is a bit of a hassle. Part of download and extract should be done in cpp/CMakeLists.txt, because of libclang completer. The resource directory should be done by both clangd and libclang, but such that they don't step on one another's toes. Should the header archives be cached somewhere? It's a bit annoying to deal with and it is not fixing a user-facing problem.

Reviewable status: 0 of 2 LGTMs obtained (waiting on @puremourning)

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update_clang_headers.py line 69 at r1 (raw file):

Previously, puremourning (Ben Jackson) wrote…

Don’t hard-code version?

Fixed.

[bstaletic]

Seems to be working!

[puremourning]

Reviewed 236 of 236 files at r2, all commit messages.
Reviewable status: 0 of 2 LGTMs obtained (waiting on @bstaletic)

[puremourning]

[puremourning]

Reviewable status: 1 of 2 LGTMs obtained (waiting on @bstaletic)

[mergify]

Thanks for sending a PR!