Release LLVM 17

[alan-j-hu]

Note that conf-llvm's configure.sh script should be unchanged from LLVM 16.

[mseri]

Is the macos failure expected? I think I remember a discussion about this in the past but cannot remember the conclusion

File "src/llvm/static/dune", line 2, characters 0-559:
#  2 | (library
#  3 |  (name llvm_static)
#  4 |  (public_name llvm.static)
#  5 |  (implements llvm)
#  6 |  (foreign_stubs
#  7 |   (language c)
#  8 |   (names llvm_ocaml)
#  9 |   (extra_deps llvm_ocaml.h)
# 10 |   (flags (-I/opt/homebrew/Cellar/llvm@17/17.0.6/include  -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS)))
# 11 |  (c_library_flags (-L/opt/homebrew/Cellar/llvm@17/17.0.6/lib -Wl,-search_paths_first -Wl,-headerpad_max_install_names -lstdc++ -lLLVMCore -lLLVMRemarks -lLLVMBitstreamReader -lLLVMBinaryFormat -lLLVMTargetParser -lLLVMSupport -lLLVMDemangle
# 12 | -lm -lz -lzstd -lcurses -lxml2)))
# (cd _build/default && /Users/mac1000/.opam/4.14.2/bin/ocamlmklib.opt -g -o src/llvm/static/llvm_static_stubs src/llvm/static/llvm_ocaml.o -ldopt -L/opt/homebrew/Cellar/llvm@17/17.0.6/lib -ldopt -Wl,-search_paths_first -ldopt -Wl,-headerpad_max_install_names -ldopt -lstdc++ -ldopt -lLLVMCore -ldopt -lLLVMRemarks -ldopt -lLLVMBitstreamReader -ldopt -lLLVMBinaryFormat -ldopt -lLLVMTargetParser -ldopt -lLLVMSupport -ldopt -lLLVMDemangle -ldopt -lm -ldopt -lz -ldopt -lzstd -ldopt -lcurses -ldopt -lxml2)
# ld: library 'zstd' not found
# clang: error: linker command failed with exit code 1 (use -v to see invocation)

[alan-j-hu]

I opened a PR at #25002 some months ago. However, it's an annoying breaking Homebrew change due to Mac's switch from Intel to ARM. Homebrew installed Intel binaries in the standard location, /usr/local, so it installs ARM binaries in a non-standard location, /opt/homebrew. Furthermore, due to security issues, Mac doesn't let you change the default library search path with LD_LIBRARY_PATH due to "System Integrity Protection" (SIP), so the libraries installed by Homebrew for ARM can't be made to be found. The OCaml LLVM package is not the only breakage by the Homebrew change. For example, I saw error messages on the Internet from people trying to use zstd (the LLVM dependency involved) purely from C on the new Macs. The Homebrew change breaks many things, because naturally tools search for libraries under standard paths, not arbitrary non-standard paths like /opt/homebrew.

The llvm-config tool does not use .pc files to search up the paths for library flags. The -lzstd flag is hardcoded in the tool. The workaround involves a new dependency on pkg-config to look up the paths via the .pc file.

This isn't the "fault" of my package, circumstances came together and Mac and Homebrew made some breaking changes with no solutions for downstream users. I'm unhappy with the "workaround," which adds a new tool dependency. I would rather Homebrew go and fix their project.

The PR was not handled because "this is a tricky package, and I suppose none of the maintainers have time to understand the various issues at play." I have no idea why it was marked as "reporter action needed" three weeks ago.

Homebrew/brew#9177

alan-j-hu/llvm-dune#18

[alan-j-hu]

I've marked this as unavailable for ARM Macs with Homebrew. I may publish a separate version, with the workaround with an additional dependency on pkg-config, for Homebrew on the ARM Macs separately.

[mseri]

I opened a PR at #25002 some months ago. However, it's an annoying breaking Homebrew change due to Mac's switch from Intel to ARM. Homebrew installed Intel binaries in the standard location, /usr/local, so it installs ARM binaries in a non-standard location, /opt/homebrew. Furthermore, due to security issues, Mac doesn't let you change the default library search path with LD_LIBRARY_PATH due to "System Integrity Protection" (SIP), so the libraries installed by Homebrew for ARM can't be made to be found. The OCaml LLVM package is not the only breakage by the Homebrew change. For example, I saw error messages on the Internet from people trying to use zstd (the LLVM dependency involved) purely from C on the new Macs. The Homebrew change breaks many things, because naturally tools search for libraries under standard paths, not arbitrary non-standard paths like /opt/homebrew.

At that is my fault sorry, I need to find some time to review it properly and understand what is going on

[mseri]

I've marked this as unavailable for ARM Macs with Homebrew. I may publish a separate version, with the workaround with an additional dependency on pkg-config, for Homebrew on the ARM Macs separately.

Sounds good

[avsm]

Thanks! You may want to announce this on https://discuss.ocaml.org, where we have a Community category and an announce tag for this purpose.