[PATCH] D132248: [CUDA][OpenMP] Fix the new driver crashing on multiple device-only outputs

[Joseph Huber via Phabricator via cfe-commits]

jhuber6 added a comment.

In D132248#3735793 <https://reviews.llvm.org/D132248#3735793>, @tra wrote:

>> The old driver would put all the outputs in the final action list akin to a linker job.
>
> IIRC that's where HIP and CUDA behaved differently. CUDA compilation does not allow device-only compilation for multiple targets if we have explicitly specified output. It does produce individual per-gpu .o files if compiled without `-o`.
>
>   bin/clang++ --cuda-path=$HOME/local/cuda-11.7 --offload-arch=sm_80 --offload-arch=sm_86 -x cuda axpy.cu  --cuda-device-only -O3  -c -o axpy.o
>   clang-15: error: cannot specify -o when generating multiple output files

Is this an architectural limitation? I'd imagine they'd just behave the same way here in my implementation.



================
Comment at: clang/test/Driver/cuda-bindings.cu:160
+// MULTI-D-ONLY-NEXT: # "nvptx64-nvidia-cuda" - "clang", inputs: ["[[INPUT]]"], output: "[[PTX_52:.+]]"
+// MULTI-D-ONLY-NEXT: # "nvptx64-nvidia-cuda" - "NVPTX::Assembler", inputs: ["[[PTX_52]]"], output: "[[CUBIN_52:.+]]"
----------------
tra wrote:
> If we've specified `-o foo.o`, where do those multiple outputs go to?
> 
> The old driver disallowed using `-o` when compiling for multiple GPUs.
Good catch, right now it'll just write both of them to the same file.


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https://reviews.llvm.org/D132248