Fails compiling with cuda

[elichai]

I tried to build cuda code using the following build script:

    cc::Build::new()
        .cuda(true)
        .cudart("static")
        .flag("arch=sm_75")
        .flag("-std=c++17")
        .include("./testing/src")
        .file("testing/src/kernel.cu")
        .compile("libtesting.a");

And got the following error:
cargo:warning=nvcc fatal : Unknown option '--target=x86_64-unknown-linux-gnu'

Apparently nvcc doesn't like this flag.
full error:

  --- stdout
  TARGET = Some("x86_64-unknown-linux-gnu")
  OPT_LEVEL = Some("0")
  HOST = Some("x86_64-unknown-linux-gnu")
  CXX_x86_64-unknown-linux-gnu = None
  CXX_x86_64_unknown_linux_gnu = None
  HOST_CXX = None
  CXX = Some("clang++ -stdlib=libc++")
  NVCC_x86_64-unknown-linux-gnu = None
  NVCC_x86_64_unknown_linux_gnu = None
  HOST_NVCC = None
  NVCC = None
  CXXFLAGS_x86_64-unknown-linux-gnu = None
  CXXFLAGS_x86_64_unknown_linux_gnu = None
  HOST_CXXFLAGS = None
  CXXFLAGS = None
  CRATE_CC_NO_DEFAULTS = None
  DEBUG = Some("true")
  running: "nvcc" "-ccbin=clang++" "-Xcompiler" "-O0" "-Xcompiler" "-ffunction-sections" "-Xcompiler" "-fdata-sections" "-Xcompiler" "-fPIC" "-G" "-Xcompiler" "-g" "-Xcompiler" "-fno-omit-frame-pointer" "--target=x86_64-unknown-linux-gnu" "-I" "./testing/src" "-Xcompiler" "-Wall" "-Xcompiler" "-Wextra" "arch=sm_75" "-std=c++17" "-o" .../src/kernel.o" "-c" "testing/src/kernel.cu"
  cargo:warning=nvcc fatal   : Unknown option '--target=x86_64-unknown-linux-gnu'
  exit status: 1

  --- stderr


  error occurred: Command "nvcc" "-ccbin=clang++" "-Xcompiler" "-O0" "-Xcompiler" "-ffunction-sections" "-Xcompiler" "-fdata-sections" "-Xcompiler" "-fPIC" "-G" "-Xcompiler" "-g" "-Xcompiler" "-fno-omit-frame-pointer" "--target=x86_64-unknown-linux-gnu" "-I" "./testing/src" "-Xcompiler" "-Wall" "-Xcompiler" "-Wextra" "arch=sm_75" "-std=c++17" "-o" "/.../src/kernel.o" "-c" "testing/src/kernel.cu" with args "nvcc" did not execute successfully (status code exit status: 1).

nvcc version:

nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2021 NVIDIA Corporation
Built on Mon_Sep_13_19:13:29_PDT_2021
Cuda compilation tools, release 11.5, V11.5.50
Build cuda_11.5.r11.5/compiler.30411180_0

[alexcrichton]

I think you'll need to configure .target(..) if because otherwise the TARGET and HOST env vars are being read which makes this look like a different compile.