[CUDA] Fix output name being replaced in device-only mode

When performing device only compilation, there was an issue where
`cubin` outputs were being renamed to `cubin` despite the user's name.
This is required in a normal compilation flow as the Nvidia tools only
understand specific filenames instead of checking magic bytes for some
unknown reason. We do not want to perform this transformation when the
user is performing device only compilation.

Reviewed By: tra

Differential Revision: https://reviews.llvm.org/D131278

Author: jhuber6

clang/lib/Driver/ToolChains/Cuda.cpp

@@ -693,8 +693,8 @@ CudaToolChain::CudaToolChain(const Driver &D, const llvm::Triple &Triple,
 
 std::string CudaToolChain::getInputFilename(const InputInfo &Input) const {
   // Only object files are changed, for example assembly files keep their .s
-  // extensions. 
-  if (Input.getType() != types::TY_Object)
+  // extensions. If the user requested device-only compilation don't change it.
+  if (Input.getType() != types::TY_Object || getDriver().offloadDeviceOnly())
     return ToolChain::getInputFilename(Input);
 
   // Replace extension for object files with cubin because nvlink relies on

clang/test/Driver/cuda-bindings.cu

@@ -135,3 +135,14 @@
 // RUN: | FileCheck -check-prefix=DASM2 %s
 // DASM2: # "nvptx64-nvidia-cuda" - "clang",{{.*}} output: "cuda-bindings-cuda-nvptx64-nvidia-cuda-sm_30.s"
 // DASM2: # "nvptx64-nvidia-cuda" - "clang",{{.*}} output: "cuda-bindings-cuda-nvptx64-nvidia-cuda-sm_35.s"
+
+//
+// Ensure we output the user's specified name in device-only mode.
+//
+// RUN: %clang -target powerpc64le-ibm-linux-gnu -### \
+// RUN:        --cuda-gpu-arch=sm_52 --cuda-device-only -c -o foo.o %s 2>&1 \
+// RUN: | FileCheck -check-prefix=D_ONLY %s
+// RUN: %clang -target powerpc64le-ibm-linux-gnu -### --offload-new-driver \
+// RUN:        --cuda-gpu-arch=sm_52 --cuda-device-only -c -o foo.o %s 2>&1 \
+// RUN: | FileCheck -check-prefix=D_ONLY %s
+// D_ONLY: "foo.o"