Add support for AMD target feature specifications in --offload-arch

[rbberger]

Using address sanitizer for ROCm seems to require to explicitly set xnack+ in the --offload-arch flag during compilation so that the necessary instrumentation is generated.

Explicitly use xnack+ in the offload architecture option. For example, --offload-arch=gfx90a:xnack+
Other architectures are allowed, but their device code will not be instrumented and a warning will be emitted.

Currently Kokkos doesn't provide a mechanism to manipulate that flag. One workaround is enabling CMake language support and taking control of that flag via CMAKE_HIP_ARCHITECTURES. However, the default CMake setup in Kokkos only lets you set architectures via the Kokkos_ARCH_AMD_<arch> Boolean options.

One proposal is to add an optional Kokkos_ARCH_AMD_TARGET_FEATURES CMake option that gets appended when set. An alternative so to provide an override to replace the entire --offload-arch=foo command-line option.

See also:

• List of target features in LLVM AMDGPU backend