tensorflow/python/distribute/parallel_device/pywrap_parallel_device.cc

/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#include "Python.h"
#include "pybind11/pybind11.h"
#include "pybind11/stl.h"
#include "tensorflow/c/c_api.h"
#include "tensorflow/c/c_api_experimental.h"
#include "tensorflow/c/eager/c_api.h"
#include "tensorflow/c/eager/c_api_experimental.h"
#include "tensorflow/c/eager/parallel_device/parallel_device.h"
#include "tensorflow/python/lib/core/py_exception_registry.h"
#include "tensorflow/python/lib/core/pybind11_lib.h"
#include "tensorflow/python/lib/core/pybind11_status.h"
#include "tensorflow/python/lib/core/safe_ptr.h"

namespace py = pybind11;

void CallDelete_Device(PyObject* capsule) {
  delete reinterpret_cast<TFE_CustomDevice*>(
      PyCapsule_GetPointer(capsule, "TFE_CustomDevice"));
}

void CallDelete_DeviceInfo(PyObject* capsule) {
  void (*destructor)(void*) =
      reinterpret_cast<void (*)(void*)>(PyCapsule_GetContext(capsule));
  destructor(PyCapsule_GetPointer(capsule, "TFE_CustomDevice_DeviceInfo"));
}

PYBIND11_MODULE(_pywrap_parallel_device, m) {
  m.def("GetParallelDeviceCapsules",
        [](const char* name, std::vector<std::string> underlying_devices) {
          std::vector<const char*> underlying_devices_c;
          underlying_devices_c.reserve(underlying_devices.size());
          for (const std::string& element : underlying_devices) {
            underlying_devices_c.push_back(element.c_str());
          }
          // `device` is owned by `device_capsule`.
          TFE_CustomDevice* device = new TFE_CustomDevice;
          tensorflow::Safe_PyObjectPtr device_capsule(
              PyCapsule_New(device, "TFE_CustomDevice", &CallDelete_Device));
          void* device_info;
          tensorflow::parallel_device::AllocateParallelDevice(
              name, underlying_devices_c.data(), underlying_devices_c.size(),
              device, &device_info);
          if (PyErr_Occurred()) throw py::error_already_set();
          tensorflow::Safe_PyObjectPtr device_info_capsule(
              PyCapsule_New(device_info, "TFE_CustomDevice_DeviceInfo",
                            &CallDelete_DeviceInfo));
          if (PyErr_Occurred()) throw py::error_already_set();
          // The PyCapsule destructor needs a pointer to the destructor for
          // DeviceInfo.
          PyCapsule_SetContext(device_info_capsule.get(),
                               reinterpret_cast<void*>(device->delete_device));
          return tensorflow::PyoOrThrow(
              PyTuple_Pack(2, device_capsule.get(), device_info_capsule.get()));
        });
}