[CUDA][HIP] Linker warnings

[krasznaa]

Describe the bug

We have been living with various warnings from the compiler (or more from the linker) in our projects since a while. I thought it may be time to get rid of them.

• Since I don't remember when exactly, we've been getting such warnings while building source files for either a CUDA or HIP backend:

warning: linking module '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-nvptx64--nvidiacl.bc': Linking two modules of different target triples: '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-nvptx64--nvidiacl.bc' is 'nvptx64-unknown-nvidiacl' whereas 'library.cxx' is 'nvptx64-nvidia-cuda'
 [-Wlinker-warnings]

warning: linking module '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-amdgcn--amdhsa.bc': Linking two modules of different target triples: '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-amdgcn--amdhsa.bc' is 'amdgcn-unknown-amdhsa' whereas 'main.cxx' is 'amdgcn-amd-amdhsa'
 [-Wlinker-warnings]

• With 2022-09 I came across this new one as well:

clang-16: warning: linked binaries do not contain expected 'nvptx64-nvidia-cuda' target; found targets: 'nvptx64-nvidia-cuda-sm_50' [-Wsycl-target]

clang-16: warning: linked binaries do not contain expected 'amdgcn-amd-amdhsa' target; found targets: 'amdgcn-amd-amdhsa-gfx803' [-Wsycl-target]

To Reproduce

The "first type of warnings" can be triggered by compiling literally any source file. Like:

[bash][pcadp04]:sycl-link > more main.cxx 
#include <CL/sycl.hpp>

int main() { return 0; }
[bash][pcadp04]:sycl-link > clang++ -fsycl -fsycl-targets=nvptx64-nvidia-cuda main.cxx 
clang-16: warning: CUDA version is newer than the latest supported version 11.5 [-Wunknown-cuda-version]
warning: linking module '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-nvptx64--nvidiacl.bc': Linking two modules of different target triples: '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-nvptx64--nvidiacl.bc' is 'nvptx64-unknown-nvidiacl' whereas 'main.cxx' is 'nvptx64-nvidia-cuda'
 [-Wlinker-warnings]
1 warning generated.
[bash][pcadp04]:sycl-link > clang++ -fsycl -fsycl-targets=amdgcn-amd-amdhsa -Xsycl-target-backend=amdgcn-amd-amdhsa --offload-arch=gfx803 main.cxx
warning: linking module '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-amdgcn--amdhsa.bc': Linking two modules of different target triples: '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-amdgcn--amdhsa.bc' is 'amdgcn-unknown-amdhsa' whereas 'main.cxx' is 'amdgcn-amd-amdhsa'
 [-Wlinker-warnings]
1 warning generated.
[bash][pcadp04]:sycl-link >

The "second one" is a bit more tricky to trigger. In our builds it shows up when linking shared libraries. Like:

[bash][pcadp04]:sycl-link > more library.cxx 
#include <CL/sycl.hpp>

int foo() {
   return 5;
}
[bash][pcadp04]:sycl-link > clang++ -fsycl -fsycl-targets=nvptx64-nvidia-cuda -c -o library.o library.cxx 
clang-16: warning: CUDA version is newer than the latest supported version 11.5 [-Wunknown-cuda-version]
warning: linking module '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-nvptx64--nvidiacl.bc': Linking two modules of different target triples: '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-nvptx64--nvidiacl.bc' is 'nvptx64-unknown-nvidiacl' whereas 'library.cxx' is 'nvptx64-nvidia-cuda'
 [-Wlinker-warnings]
1 warning generated.
[bash][pcadp04]:sycl-link > clang++ -fsycl -fsycl-targets=nvptx64-nvidia-cuda -shared -o library.so library.o
clang-16: warning: linked binaries do not contain expected 'nvptx64-nvidia-cuda' target; found targets: 'nvptx64-nvidia-cuda-sm_50' [-Wsycl-target]
clang-16: warning: CUDA version is newer than the latest supported version 11.5 [-Wunknown-cuda-version]
[bash][pcadp04]:sycl-link > clang++ -fsycl -fsycl-targets=amdgcn-amd-amdhsa -Xsycl-target-backend=amdgcn-amd-amdhsa --offload-arch=gfx803 -c -o library.o library.cxx 
warning: linking module '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-amdgcn--amdhsa.bc': Linking two modules of different target triples: '/mnt/hdd1/software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/lib/clang/16.0.0/../../clc/remangled-l64-signed_char.libspirv-amdgcn--amdhsa.bc' is 'amdgcn-unknown-amdhsa' whereas 'library.cxx' is 'amdgcn-amd-amdhsa'
 [-Wlinker-warnings]
1 warning generated.
[bash][pcadp04]:sycl-link > clang++ -fsycl -fsycl-targets=amdgcn-amd-amdhsa -Xsycl-target-backend=amdgcn-amd-amdhsa --offload-arch=gfx803 -shared -o library.so library.o
clang-16: warning: linked binaries do not contain expected 'amdgcn-amd-amdhsa' target; found targets: 'amdgcn-amd-amdhsa-gfx803' [-Wsycl-target]
[bash][pcadp04]:sycl-link >

Environment

• OS: Linux (Seen both on Ubuntu 20.04 and CentOS Stream 9. The exact Linux version shouldn't matter.)
• Target device and vendor: AMD and NVIDIA GPU, but the problem is not a runtime one
• DPC++ version:

[bash][pcadp04]:sycl-link > clang++ -v
clang version 16.0.0 (https://github.com/intel/llvm.git 0f579bae55c48d810e1ed76db29229c854e61d5e)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /software/intel/clang-2022-09/x86_64-centos9-gcc11-opt/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/11
Selected GCC installation: /usr/lib/gcc/x86_64-redhat-linux/11
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
Found CUDA installation: /mnt/hdd1/software/cuda/11.7.1/x86_64, version 
Found HIP installation: /opt/rocm, version 5.3.22061
[bash][pcadp04]:sycl-link >

• Dependencies version: Not important.

Additional context

The warnings don't seem to have any negative effect, but it's not nice that we need to explicitly hide them with -Wno-linker-warnings and -Wno-sycl-target if we don't want to see them all the time.

[npmiller]

Thank you for the report!

For the first warning we have just fixed it last week:

• [SYCL][CUDA][HIP AMD] Correct cuda/hip spirv libclc .bc and module triple. #7245

And we're also aware of the second warning, see ticket: #6636, it needs a little bit more work but we should fix it in the near future.

And you're correct that these warnings are safe to ignore, the first one was purely an issue on our side, and the second one is more meaningful but unfortunately it's a bit broken for the CUDA and HIP plugins at the moment, so it gives out a warning when it really shouldn't.

[npmiller]

The second warning should now also be fixed, see:

• [SYCL][Driver] Move offload mismatch warning into SYCLActionBuilder #7434

[npmiller]

Closing this as both warnings have been fixed, please feel free to re-open if the issue persists.