Hello World in CUDA with kernel in a DLL. I didn't know if it would work, but it does.
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Sep
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README.md
hw.sln

README.md

dllexport-of-kernels

This is an example of what and how you can compile and separately link CUDA programs and libraries. Unfortunately, I don't think NVIDIA throughly thought the various permutations of separate compilation and linking out, as there are some things you can do, and some thing you can't.

This VS 2017 solution contains two projects:

  • "hw", which is a CUDA program (.EXE) that contains a CUDA kernel call, the function defined in moduel Sep.dll.
  • "Sep", which is a DLL containing the definition for the kernel and some other things.

In Sep, the kernel is declared with "__declspec(dllexport)". It is compiled into Sep.dll/lib. Note, the NVCC compiler requires -dlink in order to build. If you don't include it, the build fails with unresolved symbols to the CUDA runtime. In "hw", the kernel is declared with "__declspec(dllimport)" and the program references the Sep.dll/lib in the link. Running the program works.

While this works for _global_ functions (i.e., kernels), it does not work for _device_ functions. While one may declare _declspec(dllexport) _device for functions in Sep, Hw cannot link with Sep.

Furthermore, there doesn't seem to be a way to load Sep.dll using the CUDA Driver API. This is unfortunately a major limitation in accessing the code in Sep.lib/dll. If you want to pre-compile a CUDA library, the only way I found that works is a static .LIB library without the -dlink option. I also believe the -dc option must be used for NVCC.