[PATCH] D151904: [clang-repl][CUDA] Add an unit test for interactive CUDA

Thu Jun 1 10:47:32 PDT 2023

tra added inline comments.

================
Comment at: clang/unittests/Interpreter/InteractiveCudaTest.cpp:92
+  std::unique_ptr<clang::Interpreter> Interp = createInterpreter();
+  auto Err = Interp->LoadDynamicLibrary("libcudart.so");
+  if (Err) { // CUDA runtime is not installed/usable, cannot continue testing
----------------
argentite wrote:
> tra wrote:
> > This could be a bit of a problem.
> > 
> > There may be multiple CUDA SDK versions that may be installed on a system at any given time and the libcudart.so you pick here may not be the one you want.
> > E.g it may be from a recent CUDA version which is not supported by NVIDIA drivers yet. 
> > 
> > I think you may need a way to let the user override CUDA SDK (or libcudart.so) location explicitly. I guess they could do that via LD_LIBRARY_PATH, but for the CUDA compilation in general, knowing CUDA SDK path is essential, as it does affect various compilation options set by the driver.
> > 
> Yes, this probably would be an issue. It is currently possible to override the CUDA path with a command line argument in clang-repl. But I am not sure what we can do inside a test.
To me it looks like CUDA location should be detected/set at the configuration time and then propagated to the individual tests that need that info.
CMake has cuda detection mechanisms that could be used for that purpose.
They are a bit of a pain to use in practice (I'm still not sure what's the reliable way to do it), but it's as close to the 'standard' way of doing it as we have at the moment.
I believe libc and mlir subtrees in LLVM are already using this mechanism. E.g https://github.com/llvm/llvm-project/blob/main/libc/utils/gpu/loader/CMakeLists.txt#L16

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  https://reviews.llvm.org/D151904/new/

https://reviews.llvm.org/D151904