Compile Cuda with Clang without .cu extension

Question

The first command, straight from the manual works, but the second does not seem to recognize the .cc file as cuda even though I have -xcuda flag.

clang++ apxy.cu --cuda-gpu-arch=sm_61 -L/usr/local/cuda/lib64 -lcudart_static -ldl -lrt -pthread

clang++ apxy.cc -xcuda --cuda-gpu-arch=sm_61 -L/usr/local/cuda/lib64 -lcudart_static -ldl -lrt -pthread

apxy.cc:3:1: error: unknown type name '__global__'__global__ void axpy(float a, float* x, float* y) {                                                                                                            │        at io.iohk.ethereum.mallet.main.Shell.<init>(Shell.scala:18)
^                                                                                                                                                              │        at io.iohk.ethereum.mallet.main.Mallet$.delayedEndpoint$io$iohk$ethereum$mallet$main$Mallet$1(Mallet.scala:20)
apxy.cc:3:12: error: expected unqualified-id                                                                                                                   │        at io.iohk.ethereum.mallet.main.Mallet$delayedInit$body.apply(Mallet.scala:13)
__global__ void axpy(float a, float* x, float* y) {                                                                                                            │        at scala.Function0.apply$mcV$sp(Function0.scala:34)
           ^                                                                                                                                                   │        at scala.Function0.apply$mcV$sp$(Function0.scala:34)
apxy.cc:17:3: error: use of undeclared identifier 'cudaMalloc'                                                                                                 │        at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
  cudaMalloc(&device_x, kDataLen * sizeof(float));

WeaZeLb0y WeaZeLb0y · Accepted Answer · 2018-08-01T00:17:39

My problem was I needed the -xcuda to go before the filename. Here is an example using Bazel.

WORKSPACE

new_local_repository(
    name = "cuda",
    path = "/usr/local/cuda",
    build_file_content = """
cc_library(
    name = "cuda",
    hdrs = glob(["**/*.h", "**/*.hpp", ]),
    includes = ["include/"],
    linkopts = ["-L/usr/local/cuda/lib64 -lcudart_static -ldl -lrt -pthread"],
    visibility = ["//visibility:public"],
)
    """
)

BUILD

cc_binary(
    name = "example",
    srcs = ["example.cu.cc"],
    copts = ["-xcuda --cuda-gpu-arch=sm_61"],
    deps = ["@cuda"],
)

Compile Cuda with Clang without .cu extension

2 Answers