No luck with C++14

TL;DR: you need to have host and device compiler either both using c++17 or neither using c++17.

Long version:
C++17 among other things changed how static constexpr member variables for classes worked. Previously if I had a class with a static constexpr member variable I would have to not only declare it inline within the class, but also define it within an executable otherwise the variable would not actually have any physical memory address:

// foo.hpp
class foo
{
  static constexpr int bar = 5;
};

// foo.cpp
int foo::bar;

In c++17 however this changed because you can have static “inline” variables. All this does is force the compiler define the variable for you instead. The issue of course is that static constexpr implicitly makes that variable inline in c++17. So to sum it up:

1. The c++17 compiler (nvcc) sees the static constexpr variable, goes “hmm ok I will define this in some undefined location”.
2. The c++11/14 compiler comes along, sees your hand-coded definition of the variable and goes “ah but I think I’ve seen this before, I’ll ignore it”. This silent rejection is due to the hand-coded definition idiom being deprecated from c++17 onwards. Stupid, I know.
2. The linker (driven by the c++11/14 compiler since PETSc links using the host compiler) comes along and now suddenly cannot find the literal definition, because it doesn’t know what the c++17 did. Disaster!

Best regards,

Jacob Faibussowitsch
(Jacob Fai - booss - oh - vitch)

On Aug 30, 2021, at 10:12, Mark Adams <mfadams@lbl.gov> wrote:

No luck with C++14

       CUDAC arch-summit-hypre-cuda-dbg/obj/vec/is/sf/impls/basic/cuda/sfcuda.o
   CUDAC.dep arch-summit-hypre-cuda-dbg/obj/vec/is/sf/impls/basic/cuda/sfcuda.o
     CLINKER arch-summit-hypre-cuda-dbg/lib/libpetsc.so.3.015.3
arch-summit-hypre-cuda-dbg/obj/sys/objects/device/impls/cupm/cuda/cupmcontext.o:(.rodata._ZN5Petsc13CUPMInterfaceILNS_14CUPMDeviceKindE0EE21cupmStreamNonBlockingE[_ZN5Petsc13CUPMInterfaceILNS_14CUPMDeviceKindE0EE21cupmStreamNonBlockingE]+0x0): multiple definition of `Petsc::CUPMInterface<(Petsc::CUPMDeviceKind)0>::cupmStreamNonBlocking'
arch-summit-hypre-cuda-dbg/obj/sys/objects/device/interface/cupminterface.o:(.rodata+0x44): first defined here
/usr/bin/ld: link errors found, deleting executable `arch-summit-hypre-cuda-dbg/lib/libpetsc.so.3.015.3'
collect2: error: ld returned 1 exit status
gmake[3]: *** [gmakefile:113: arch-summit-hypre-cuda-dbg/lib/libpetsc.so.3.015.3] Error 1
gmake[2]: *** [/gpfs/alpine/csc314/scratch/adams/petsc2/lib/petsc/conf/rules:50: libs] Error 2
**************************ERROR*************************************
  Error during compile, check arch-summit-hypre-cuda-dbg/lib/petsc/conf/make.log
  Send it and arch-summit-hypre-cuda-dbg/lib/petsc/conf/configure.log to petsc-maint@mcs.anl.gov
********************************************************************
gmake[1]: *** [makefile:40: all] Error 1

On Mon, Aug 30, 2021 at 10:50 AM Mark Adams <mfadams@lbl.gov> wrote:
Stefano suggested C++14 in configure. I was using C++11.

On Mon, Aug 30, 2021 at 10:46 AM Junchao Zhang <junchao.zhang@gmail.com> wrote:
 Petsc::CUPMInterface
@Jacob Faibussowitsch 
--Junchao Zhang


On Mon, Aug 30, 2021 at 9:35 AM Mark Adams <mfadams@lbl.gov> wrote:
I was running fine this AM and am bouncing between modules to help two apps (ECP milestone season) at the same time and something broke. I did update main and I get the same error in main and a hypre branch of Stefano's. 
I started with a clean build and checked my modules...
Any ideas?

Thanks,
Mark

       CC arch-summit-hypre-cuda-dbg/obj/tao/interface/taosolver.o
          CC arch-summit-hypre-cuda-dbg/obj/ts/interface/ts.o
       CUDAC arch-summit-hypre-cuda-dbg/obj/mat/impls/dense/seq/cuda/densecuda.o
   CUDAC.dep arch-summit-hypre-cuda-dbg/obj/mat/impls/dense/seq/cuda/densecuda.o
       CUDAC arch-summit-hypre-cuda-dbg/obj/mat/impls/aij/seq/seqcusparse/aijcusparseband.o
   CUDAC.dep arch-summit-hypre-cuda-dbg/obj/mat/impls/aij/seq/seqcusparse/aijcusparseband.o
       CUDAC arch-summit-hypre-cuda-dbg/obj/ts/utils/dmplexlandau/cuda/landaucu.o
   CUDAC.dep arch-summit-hypre-cuda-dbg/obj/ts/utils/dmplexlandau/cuda/landaucu.o
       CUDAC arch-summit-hypre-cuda-dbg/obj/vec/vec/impls/seq/seqcuda/veccuda2.o
   CUDAC.dep arch-summit-hypre-cuda-dbg/obj/vec/vec/impls/seq/seqcuda/veccuda2.o
       CUDAC arch-summit-hypre-cuda-dbg/obj/mat/impls/aij/mpi/mpicusparse/mpiaijcusparse.o
   CUDAC.dep arch-summit-hypre-cuda-dbg/obj/mat/impls/aij/mpi/mpicusparse/mpiaijcusparse.o
       CUDAC arch-summit-hypre-cuda-dbg/obj/mat/impls/aij/seq/seqcusparse/aijcusparse.o
   CUDAC.dep arch-summit-hypre-cuda-dbg/obj/mat/impls/aij/seq/seqcusparse/aijcusparse.o
       CUDAC arch-summit-hypre-cuda-dbg/obj/vec/is/sf/impls/basic/cuda/sfcuda.o
   CUDAC.dep arch-summit-hypre-cuda-dbg/obj/vec/is/sf/impls/basic/cuda/sfcuda.o
     CLINKER arch-summit-hypre-cuda-dbg/lib/libpetsc.so.3.015.3
arch-summit-hypre-cuda-dbg/obj/sys/objects/device/impls/cupm/cuda/cupmcontext.o:(.rodata._ZN5Petsc13CUPMInterfaceILNS_14CUPMDeviceKindE0EE21cupmStreamNonBlockingE[_ZN5Petsc13CUPMInterfaceILNS_14CUPMDeviceKindE0EE21cupmStreamNonBlockingE]+0x0): multiple definition of `Petsc::CUPMInterface<(Petsc::CUPMDeviceKind)0>::cupmStreamNonBlocking'
arch-summit-hypre-cuda-dbg/obj/sys/objects/device/interface/cupminterface.o:(.rodata+0x44): first defined here
/usr/bin/ld: link errors found, deleting executable `arch-summit-hypre-cuda-dbg/lib/libpetsc.so.3.015.3'
collect2: error: ld returned 1 exit status
gmake[3]: *** [gmakefile:113: arch-summit-hypre-cuda-dbg/lib/libpetsc.so.3.015.3] Error 1
gmake[2]: *** [/gpfs/alpine/csc314/scratch/adams/petsc2/lib/petsc/conf/rules:50: libs] Error 2
**************************ERROR*************************************
  Error during compile, check arch-summit-hypre-cuda-dbg/lib/petsc/conf/make.log
  Send it and arch-summit-hypre-cuda-dbg/lib/petsc/conf/configure.log to petsc-maint@mcs.anl.gov
********************************************************************
gmake[1]: *** [makefile:40: all] Error 1
make: *** [GNUmakefile:9: all] Error 2