Method ModifyGraphWithDelegate

tensorflow/lite/core/subgraph.cc:1169–1246

}

TfLiteStatus Subgraph::ModifyGraphWithDelegate(TfLiteDelegate* delegate) {
  // Restore delegation state if applicable.
  TF_LITE_ENSURE_STATUS(RedoAllDelegates());

  if (state_ == kStateInvokableAndImmutable) {
    ReportError(
        "ModifyGraphWithDelegate is disallowed when graph is immutable.");
    return kTfLiteError;
  }

  if (!(delegate->flags & kTfLiteDelegateFlagsAllowDynamicTensors)) {
    int last_execution_plan_index_prepared;
    TF_LITE_ENSURE_OK(&context_, PrepareOpsStartingAt(
                                     0, &last_execution_plan_index_prepared));
    if (has_dynamic_tensors_) {
      // Make sure that we are in a defined ready state before returning.
      // Plan and allocate tensors before returning.
      TF_LITE_ENSURE_OK(&context_, EnsureMemoryAllocations());
      ReportError(
          "Attempting to use a delegate that only supports static-sized "
          "tensors with a graph that has dynamic-sized tensors.");
      return kTfLiteError;
    }
  }

  const bool was_invokable_before_delegate = state_ == kStateInvokable;
  if (delegates_applied_.empty()) {
    // This is the first delegate being applied, so remember original execution
    // plan.
    // TODO(b/119623453): Restore execution plan to this state if delegate
    // application fails.
    pre_delegation_execution_plan_ = execution_plan_;
  }

  // TODO(aselle): Consider if it is worth storing pointers to delegates.
  // Setup additional context interface.
  SwitchToDelegateContext();

  auto reset_delegation_if_not_ok = [this](TfLiteStatus status) {
    if (status != kTfLiteOk) {
      // This will undo all delegate nodes currently in the graph.
      TF_LITE_ENSURE_STATUS(this->UndoAllDelegates());
      // This will call AllocateTensors, thus-reapplying any (successfully
      // applied) previous delegates.
      TF_LITE_ENSURE_STATUS(this->EnsureMemoryAllocations());
      ReportError(
          "Restored previous execution plan after delegate application "
          "failure.");
      return kTfLiteError;
    }
    return kTfLiteOk;
  };

  TfLiteStatus status = delegate->Prepare(&context_, delegate);

  // Remove additional context info.
  SwitchToKernelContext();