Operator new in CUDA kernels

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Operator new in CUDA kernels

Adam Cieszkiel via cfe-dev
I’m trying to port my CUDA project to clang. Thanks for the fantastic work,
clang is a charm to work with.

One problem however, maybe you guys can help me out. I already posted this
to cfe-users but no answer so far.

I need to allocate memory for a class in a CUDA kernel on the heap.
So I created a myclass** in the host program, pass it to the kernel and attempt to
allocate with new. Works fine in nvcc, in clang I get the error

[1] % clang++ -std=c++14 -o test_new_device test_new_device.cu -L/Developer/NVIDIA/CUDA-8.0/lib -lcudart
ptxas fatal   : Unresolved extern function '_Znwm'
clang-4.0: error: ptxas command failed with exit code 255 (use -v to see invocation)

I’m on osx 10.12.5, using
% clang++ --version
clang version 4.0.0 (tags/RELEASE_400/final 297808)
Target: x86_64-apple-darwin16.6.0
Thread model: posix

So, is there a way to tell clang that ::operator new() in device function should call
the device version of malloc. As described here:

Below is a minimal program that reproduces the error.


#include <iostream>
#include <cuda_runtime_api.h>

class myclass
   __host__ __device__ myclass(const double _data) : data(_data) {}
   __host__ __device__ ~myclass()
       printf("Deleting myclass\n");
   __host__ __device__ double get_data() const {return(data);}

   const double data;

void init_myclass(myclass** mycs_ptr)
   (*mycs_ptr) = new myclass(14.0);

void access_myclass(myclass** mycs_ptr)
   printf("I am using data with value = %f\n", (*mycs_ptr) -> get_data());

void delete_myclass(myclass** mycs_ptr)
   delete (*mycs_ptr);

int main(void)
   myclass** myclass_ptr{nullptr};

   init_myclass<<<1, 1>>>(myclass_ptr);

   access_myclass<<<1, 1>>>(myclass_ptr);

   delete_myclass<<<1, 1>>>(myclass_ptr);

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