Compilation with Kokkos develop broken after Kokkos PR 7394

[maartenarnst]

Compilation of kokkos-tools with kokkos develop is broken after

• https://github.com/kokkos/kokkos/pull/7394

The reason seems to be that the kokkos PR moved the function int_for_synchronization_reason from Kokkos_Profiling.hpp to Kokkos_Profiling_Interface.hpp. However, this file Kokkos_Profiling_Interface.hpp is also in kokkos-tools/profiling/all/impl. And so because of the kokkos PR, the two files are no longer in sync.

When we now compile kokkos-tools with kokkos develop, we get a compilation error saying that the compiler can't find int_for_synchronization_reason. The compilation error arises when compiling the kokkos-tools tests. That's indeed where both kokkos-tools and kokkos are needed, and the two versions of the same header being out of sync can cause a problem.

In file included from /opt/kokkos/include/impl/Kokkos_Tools.hpp:24,
                 from /opt/kokkos/include/Kokkos_HostSpace.hpp:37,
                 from /opt/kokkos/include/OpenMP/Kokkos_OpenMP.hpp:30,
                 from /opt/kokkos/include/decl/Kokkos_Declare_OPENMP.hpp:21,
                 from /opt/kokkos/include/KokkosCore_Config_DeclareBackend.hpp:22,
                 from /opt/kokkos/include/Kokkos_Core.hpp:45,
                 from /workspaces/kokkos/kokkos-tools/tests/UnitTestMain.cpp:3:
/opt/kokkos/include/impl/Kokkos_Profiling.hpp: In function 'void Kokkos::Tools::Experimental::Impl::profile_fence_event(const std::string&, Kokkos::Tools::Experimental::SpecialSynchronizationCases, const FencingFunctor&)':
/opt/kokkos/include/impl/Kokkos_Profiling.hpp:211:39: error: there are no arguments to 'int_for_synchronization_reason' that depend on a template parameter, so a declaration of 'int_for_synchronization_reason' must be available [-fpermissive]
  211 |       name, device_id_root<Space>() + int_for_synchronization_reason(reason),

The reason that the kokkos-tools version of Kokkos_Profiling_Interface.hpp has precedence over the kokkos version, and we thus get the error here, seems be that kokkos-tools uses hard include_directories rather than a CMake target:

• https://github.com/kokkos/kokkos-tools/blob/a9453b21e09c7555096f3a96bb3fa8b34afe19f8/CMakeLists.txt#L119-L126

Unfortunately, simply updating kokkos-tools/profiling/all/impl/Kokkos_Profiling_Interface.hpp does not seem to be a good solution. When we update this file, compilation works with kokkos develop. However, when we update this file and then compile with kokkos 4.4.1, compilation fails because there are now two definitions of int_for_synchronization_reason ("ambiguous ...").

A "quick fix" would be to update kokkos-tools/profiling/all/impl/Kokkos_Profiling_Interface.hpp by adding the function protected by "#if KOKKOS_VERSION >= 40499". However, this may not be a good fix, because the versions of this file in Kokkos and kokkos-tools would then be indefinitely out of sync.

@csiefer2 @crtrott @dalg24 @romintomasetti