/* Copyright 2017 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 "tensorflow/compiler/xla/service/interpreter/executor.h"

#include <cstring>

#include "tensorflow/compiler/xla/status_macros.h"

namespace stream_executor {
namespace interpreter {

host::HostStream *AsExecutorStream(Stream *stream) {
  DCHECK(stream != nullptr);
  return dynamic_cast<host::HostStream *>(stream->implementation());
}

XlaInterpreterExecutor::XlaInterpreterExecutor(
    const PluginConfig &plugin_config)
    : plugin_config_(plugin_config) {}

XlaInterpreterExecutor::~XlaInterpreterExecutor() {}

DeviceMemoryBase XlaInterpreterExecutor::Allocate(uint64 size,
                                                  int64 memory_space) {
  CHECK_EQ(memory_space, 0);
  return DeviceMemoryBase(new char[size], size);
}

void *XlaInterpreterExecutor::GetSubBuffer(DeviceMemoryBase *parent,
                                           uint64 offset_bytes,
                                           uint64 /*size_bytes*/) {
  return parent + offset_bytes;
}

void XlaInterpreterExecutor::Deallocate(DeviceMemoryBase *mem) {
  delete[] static_cast<char *>(mem->opaque());
}

bool XlaInterpreterExecutor::Memcpy(Stream *stream, void *host_dst,
                                    const DeviceMemoryBase &dev_src,
                                    uint64 size) {
  AsExecutorStream(stream)->EnqueueTask([this, host_dst, dev_src, size]() {
    port::Status ok = SynchronousMemcpy(host_dst, dev_src, size);
  });
  AsExecutorStream(stream)->BlockUntilDone();
  return true;
}

bool XlaInterpreterExecutor::Memcpy(Stream *stream, DeviceMemoryBase *dev_dst,
                                    const void *host_src, uint64 size) {
  AsExecutorStream(stream)->EnqueueTask([this, dev_dst, host_src, size]() {
    port::Status ok = SynchronousMemcpy(dev_dst, host_src, size);
  });
  AsExecutorStream(stream)->BlockUntilDone();
  return true;
}

port::Status XlaInterpreterExecutor::SynchronousMemcpy(
    DeviceMemoryBase *dev_dst, const void *host_src, uint64 size) {
  memcpy(dev_dst->opaque(), host_src, size);
  return port::Status::OK();
}

port::Status XlaInterpreterExecutor::SynchronousMemcpy(
    void *host_dst, const DeviceMemoryBase &dev_src, uint64 size) {
  memcpy(host_dst, dev_src.opaque(), size);
  return port::Status::OK();
}

bool XlaInterpreterExecutor::HostCallback(
    Stream *stream, std::function<port::Status()> callback) {
  AsExecutorStream(stream)->EnqueueTask([callback]() {
    port::Status s = callback();
    if (!s.ok()) {
      LOG(WARNING) << "Host callback failed: " << s;
    }
  });
  return true;
}

bool XlaInterpreterExecutor::CreateStreamDependency(Stream *dependent,
                                                    Stream *other) {
  AsExecutorStream(dependent)->EnqueueTask(
      [other]() { SE_CHECK_OK(other->BlockHostUntilDone()); });
  AsExecutorStream(dependent)->BlockUntilDone();
  return true;
}

bool XlaInterpreterExecutor::StartTimer(Stream *stream, Timer *timer) {
  dynamic_cast<host::HostTimer *>(timer->implementation())->Start(stream);
  return true;
}

bool XlaInterpreterExecutor::StopTimer(Stream *stream, Timer *timer) {
  dynamic_cast<host::HostTimer *>(timer->implementation())->Stop(stream);
  return true;
}

port::Status XlaInterpreterExecutor::BlockHostUntilDone(Stream *stream) {
  AsExecutorStream(stream)->BlockUntilDone();
  return port::Status::OK();
}

port::StatusOr<std::unique_ptr<DeviceDescription>>
XlaInterpreterExecutor::CreateDeviceDescription(int device_ordinal) {
  internal::DeviceDescriptionBuilder builder;

  builder.set_device_address_bits(64);

  builder.set_name("Interpreter");
  builder.set_device_memory_size(static_cast<uint64>(4) * 1024 * 1024 * 1024);
  builder.set_clock_rate_ghz(static_cast<float>(CLOCKS_PER_SEC) / 1e9);

  return builder.Build();
}

}  // namespace interpreter
}  // namespace stream_executor
