Fix async_io ops building error on Huawei Ascend NPU (#7894)
### Summary
Fixes async_io ops building error on Huawei Ascend NPU.
### Environment
| Item | Version |
| -------------------------- | ------------------ |
| kernel version | 5.15.0-101-generic |
| torch version | 2.8.0+cpu |
| deepspeed info | 0.18.7 |
| deepspeed wheel compiled w | torch 2.8 |
| torch_npu version | 2.8.0 |
| ascend_cann version | 8.1.RC1 |
Deepspeed config "zero_optimization.offload_optimizer.device" = "nvme"
(device = "cpu" works).
### Error Messages
When offloading from NPU to NVME, error occurs:
```text
ImportError: /.../async_io.so: undefined symbol: _ZN21deepspeed_io_handle_t18_create_io_op_descEbRKN2at6TensorEiPKcbl
```
nm tells that the symbol is declared but not defined, but it's found at
"csrc/aio/py_lib/deepspeed_py_io_handle.cpp":
```sh
nm async_io.so | rg _ZN21deepspeed_io_handle_t18_create_io_op_descEbRKN2at6TensorEiPKcbl
# U _ZN21deepspeed_io_handle_t18_create_io_op_descEbRKN2at6TensorEiPKcbl
```
# Solution
1. `op_builder/npu/async_io.py`:
```python
class AsyncIOBuilder(NPUOpBuilder):
def sources(self):
return [
'csrc/aio/py_lib/deepspeed_py_copy.cpp', 'csrc/aio/py_lib/py_ds_aio.cpp',
'csrc/aio/py_lib/deepspeed_py_aio.cpp', 'csrc/aio/py_lib/deepspeed_py_aio_handle.cpp',
'csrc/aio/py_lib/deepspeed_aio_thread.cpp', 'csrc/aio/common/deepspeed_aio_utils.cpp',
'csrc/aio/common/deepspeed_aio_common.cpp', 'csrc/aio/common/deepspeed_aio_types.cpp',
'csrc/aio/py_lib/deepspeed_pin_tensor.cpp',
# Adds 3 source files:
'csrc/aio/py_lib/deepspeed_py_io_handle.cpp',
'csrc/aio/py_lib/deepspeed_aio_op_desc.cpp',
'csrc/aio/py_lib/deepspeed_cpu_op.cpp'
]
```
2. `csrc/aio/py_lib/deepspeed_cpu_op.cpp`:
```cpp
#if defined(__ENABLE_CANN__)
// `DS_BUILD_OPS=1 install.sh` complains that ‘torch_npu’ has not
// been declared, so inlines `torch_npu::utils::is_npu`.
if (_buffer.is_privateuseone()) {
auto device = at::Device("npu:0");
_buffer.copy_(_cpu_buffer.to(device));
}
#endif
```
Signed-off-by: Huang Yifan <yifan0610@foxmail.com>
Co-authored-by: Olatunji Ruwase <tunji.ruwase@snowflake.com>
