[onert] Load tensor and optimizer data from the checkpoint file

This commit loads tensor and optimizer data from the checkpoint file.

ONE-DCO-1.0-Signed-off-by: Jiyoung Yun <jy910.yun@samsung.com>

runtime/onert/core/src/loader/train/CheckpointLoader.cc

@@ -32,6 +32,48 @@ using namespace train;
 using namespace checkpoint;
 using namespace exec;
 
+struct DataBufferPair
+{
+  uint32_t offset;
+  uint32_t size;
+};
+
+class DataBuffer
+{
+public:
+  DataBuffer() = default;
+  DataBuffer(uint32_t size) { setSize(size); }
+
+  void setSize(uint32_t size)
+  {
+    _offset.resize(size);
+    _size.resize(size);
+  }
+
+  char *getOffsetBuf() { return reinterpret_cast<char *>(_offset.data()); }
+
+  // This function should be called after loading the _offset buffer.
+  void calculateSize(uint32_t next_start_offset)
+  {
+    assert(_offset.size() == _size.size());
+    for (size_t i = 0; i < _offset.size() - 1; ++i)
+      _size[i] = _offset[i + 1] - _offset[i];
+    _size.back() = next_start_offset - _offset.back();
+  }
+
+  // offset, size
+  DataBufferPair operator[](uint32_t i) const
+  {
+    assert(_offset.size() == _size.size());
+    assert(i <= _offset.size());
+    return DataBufferPair{_offset[i], _size[i]};
+  }
+
+private:
+  std::vector<uint32_t> _offset;
+  std::vector<uint32_t> _size;
+};
+
 class CheckpointLoader final
 {
 public:
@@ -62,6 +104,30 @@ class CheckpointLoader final
     if (_header.schema != checkpoint::SCHEMA_VERSION)
       throw std::runtime_error{"Invalid SCHEMA VERSION"};
 
+    _tensor_data.setSize(_header.length);
+    _file.read(_tensor_data.getOffsetBuf(), _header.length * sizeof(uint32_t));
+    if (_file.fail())
+      throw std::runtime_error{"Failed to load tensor data"};
+    _tensor_data.calculateSize(_header.opt1_offset);
+
+    if (_header.opt1_offset)
+    {
+      DataBuffer opt1_data(_header.length);
+      _file.seekg(_header.opt1_offset, std::ios::beg);
+      _file.read(opt1_data.getOffsetBuf(), _header.length * sizeof(uint32_t));
+      opt1_data.calculateSize(_header.opt2_offset);
+      _optimizer_data.emplace_back(std::move(opt1_data));
+    }
+
+    if (_header.opt2_offset)
+    {
+      DataBuffer opt2_data(_header.length);
+      _file.seekg(_header.opt2_offset, std::ios::beg);
+      _file.read(opt2_data.getOffsetBuf(), _header.length * sizeof(uint32_t));
+      opt2_data.calculateSize(_header.other_offset);
+      _optimizer_data.emplace_back(std::move(opt2_data));
+    }
+
     if ((filesize - _header.other_offset) != sizeof(_footer))
       throw std::runtime_error{"Invalid checkpoint file footer data"};
 
@@ -76,10 +142,93 @@ class CheckpointLoader final
       _file.close();
   }
 
+  void updateTensor(const std::unique_ptr<exec::Execution> &exec)
+  {
+    uint32_t vindex = 0;
+    exec->iterateTrainableTensors(
+      [&](const ir::OperandIndex &, const backend::train::ITrainableTensor *) { vindex++; });
+
+    if (_header.length != vindex)
+      throw std::runtime_error{
+        "Invalid number of tensors between TrainingInfo and checkpoint file"};
+
+    // Reset EOF bit
+    _file.clear();
+
+    vindex = 0;
+    exec->iterateTrainableTensors(
+      [&](const ir::OperandIndex &, const backend::train::ITrainableTensor *tensor) {
+        assert(tensor);
+        assert(_tensor_data[vindex].size == tensor->total_size());
+        _file.seekg(_tensor_data[vindex].offset, std::ios::beg);
+        _file.read(reinterpret_cast<char *>(tensor->buffer()), tensor->total_size());
+        vindex++;
+      });
+  }
+
+  void updateOptimizer(const std::unique_ptr<ir::train::TrainingInfo> &train_info,
+                       const std::unique_ptr<onert::exec::Execution> &exec)
+  {
+    ir::train::OptimizerCode ckpt_opt_code = ir::train::OptimizerCode::SGD;
+    // TODO Support other optimizers
+    if (_optimizer_data.size() == 2)
+      ckpt_opt_code = ir::train::OptimizerCode::Adam;
+
+    if (ckpt_opt_code != train_info->optimizerInfo().optim_code)
+      throw std::runtime_error{
+        "Not compatible optimizer type between TrainingInfo and checkpoint file"};
+
+    switch (train_info->optimizerInfo().optim_code)
+    {
+      case ir::train::OptimizerCode::Adam:
+        updateAdamOptimizer(exec);
+        break;
+      default:
+        break;
+    }
+  }
+
+  void updateTrainingInfo(const std::unique_ptr<ir::train::TrainingInfo> &train_info)
+  {
+    // TODO Verify cur_step value
+    train_info->trainingStep() = _footer.cur_step;
+  }
+
+private:
+  void updateAdamOptimizer(const std::unique_ptr<onert::exec::Execution> &exec)
+  {
+    // Adam optimizer has two optimizer variables. (mean, variance)
+    [[maybe_unused]] constexpr auto ADAM_VARIABLE_COUNT = 2;
+
+    // Reset EOF bit
+    _file.clear();
+
+    auto vindex = 0;
+    exec->iterateTrainableTensors(
+      [&](const ir::OperandIndex &, const backend::train::ITrainableTensor *tensor) {
+        assert(tensor);
+        auto trainable_tensor = const_cast<backend::train::ITrainableTensor *>(tensor);
+        const auto opt_vars = trainable_tensor->optVars();
+
+        // Untrainable tensor should not have any optimizer variables.
+        assert(opt_vars.size() == ADAM_VARIABLE_COUNT || opt_vars.size() == 0);
+
+        for (size_t i = 0; i < opt_vars.size(); ++i)
+        {
+          assert(opt_vars[i]->total_size() == _optimizer_data[i][vindex].size);
+          _file.seekg(_optimizer_data[i][vindex].offset, std::ios::beg);
+          _file.read(reinterpret_cast<char *>(opt_vars[i]->buffer()), opt_vars[i]->total_size());
+        }
+        vindex++;
+      });
+  }
+
 private:
   std::ifstream _file;
   checkpoint::Header _header;
   checkpoint::Footer _footer;
+  DataBuffer _tensor_data;
+  std::vector<DataBuffer> _optimizer_data;
 };
 
 } // namespace
@@ -96,11 +245,9 @@ void loadCheckpoint(const std::string &filename,
                     const std::unique_ptr<onert::exec::Execution> &exec)
 {
   CheckpointLoader loader(filename);
-
-  // TODO Load tensor data
-  UNUSED_RELEASE(exec);
-  // TODO Update step in train_info
-  UNUSED_RELEASE(train_info);
+  loader.updateTensor(exec);
+  loader.updateOptimizer(train_info, exec);
+  loader.updateTrainingInfo(train_info);
 }
 
 } // namespace train