extern "C" (on declaration only) produces mangled symbols for __host__ functions

[jithunnair-amd]

If a __host__ function is declared as extern "C", but the definition isn't labelled as extern "C", hipcc/hcc produces a mangled symbol in the resulting object file. However, if the definition also has an extern "C" label, the symbol is non-mangled as expected. Also, this unexpected behaviour doesn't occur for __global__ functions (they produce the expected non-mangled symbol regardless of whether the definition also has an extern "C"). Below is a testcase for the same:

experiment.h:
extern "C" void FuncA(int exp);

experiment.cu:
#include <stdio.h>
#include "experiment.h"
#include "hip/hip_runtime.h"

/*extern "C"*/ __host__ void FuncA(int exp) {
printf("I got %d", exp);
}

Compile command: hipcc -fPIC -c experiment.cu -o experiment.o

rocm-user@51f7736e9394:~/experiment$ nm experiment.o | grep FuncA
00000000000038e0 T _Z5FuncAi

[whchung]

from the look of it it's related to HCC Clang CodeGen. probably better file the ticket in hcc repo

[jithunnair-amd]

Closing this issue because opened identical issue in HCC: ROCm/hcc#839