macOS Fixes, main branch (2024.08.14.)

[krasznaa]

Triggered by @paulgessinger pointing out that the latest version of the code doesn't work on macOS, this is what I had to do to fix that.

As it happens, the _LIBCUDACXX_STRING_H_HAS_CONST_OVERLOADS definition makes the code, or at least the part of it that we use, work on macOS. So I added a bit of code that would add _LIBCUDACXX_STRING_H_HAS_CONST_OVERLOADS to the _Thrust_Thrust target, if it seems that it's needed. I decided to do this only for the case where we build Thrust / CCCL ourselves. Since on macOS we would always do this. (With CUDA not actually supporting macOS.) Plus we can really only vouch for the behaviour of _LIBCUDACXX_STRING_H_HAS_CONST_OVERLOADS on the exact version of CCCL that we download ourselves. On any other version all bets are off with how it would work on macOS. 🤔

The fix in clustering_config.hpp is a much more straight forward affair on the other hand. 😉

@beomki-yeo and @paulgessinger: I'm happy for one of you to set up a macOS CI for the repository. I was not keen on bothering with that myself. (We only need Boost on macOS that may not be available right away on the CI machines.)

Note: It might be worth noting that it's the following code that _LIBCUDACXX_STRING_H_HAS_CONST_OVERLOADS affects:

https://github.com/NVIDIA/cccl/blob/v2.5.0/libcudacxx/include/cuda/std/detail/libcxx/include/string.h#L73

Deep, deep inside of the CCCL code...

[paulgessinger]

Pretty hacky but I guess it gets the job done.

[krasznaa]

Curiously, while a "Makefile based" build works fine for me (latest macOS + Xcode) with these changes

, I can not generate an Xcode project for the code as it seems.

...
-- Building Acts as part of the TRACCC project
-- Are C++20 concepts supported
-- Are C++20 concepts supported - no
-- Found Boost: /Users/krasznaa/Software/Boost/1.83.0/lib/cmake/Boost-1.83.0/BoostConfig.cmake (found suitable version "1.83.0", minimum required is "1.71.0")  
-- Looking for C++ include filesystem
-- Looking for C++ include filesystem - found
-- Performing Test CXX_FILESYSTEM_NO_LINK_NEEDED
-- Performing Test CXX_FILESYSTEM_NO_LINK_NEEDED - Failed
-- Performing Test CXX_FILESYSTEM_STDCPPFS_NEEDED
-- Performing Test CXX_FILESYSTEM_STDCPPFS_NEEDED - Failed
-- Performing Test CXX_FILESYSTEM_CPPFS_NEEDED
-- Performing Test CXX_FILESYSTEM_CPPFS_NEEDED - Failed
CMake Error at /Users/krasznaa/ATLAS/projects/traccc/build-xcode/_deps/acts-src/cmake/FindFilesystem.cmake:248 (message):
  Cannot run simple program using std::filesystem
Call Stack (most recent call first):
  /Users/krasznaa/ATLAS/projects/traccc/build-xcode/_deps/acts-src/CMakeLists.txt:241 (find_package)


-- Configuring incomplete, errors occurred!
See also "/Users/krasznaa/ATLAS/projects/traccc/build-xcode/CMakeFiles/CMakeOutput.log".
See also "/Users/krasznaa/ATLAS/projects/traccc/build-xcode/CMakeFiles/CMakeError.log".

Is this tested in the Acts CI? That -G Xcode would work...?

[paulgessinger]

Is this tested in the Acts CI? That -G Xcode would work...?

No, we don't support Xcode on macOS at all.

[krasznaa]

No, we don't support Xcode on macOS at all.

Which is just as well. Since it seems to have some nasty issues. 😦 As you can see in the log, before failing on std::filesystem, it also cannot make use of C++20 concepts.

But I'm not willing to debug that any further.