Free Convolution and MatMul weights after TensorFlow layers import

modules/dnn/src/tensorflow/tf_graph_simplifier.cpp

@@ -612,7 +612,7 @@ void RemoveIdentityOps(tensorflow::GraphDef& net)
 
 Mat getTensorContent(const tensorflow::TensorProto &tensor)
 {
-    std::string content = tensor.tensor_content();
+    const std::string& content = tensor.tensor_content();
     switch (tensor.dtype())
     {
         case tensorflow::DT_FLOAT:
@@ -681,6 +681,14 @@ Mat getTensorContent(const tensorflow::TensorProto &tensor)
     return Mat();
 }
 
+void releaseTensor(tensorflow::TensorProto* tensor)
+{
+    if (!tensor->mutable_tensor_content()->empty())
+    {
+        delete tensor->release_tensor_content();
+    }
+}
+
 CV__DNN_EXPERIMENTAL_NS_END
 }}  // namespace dnn, namespace cv
 

modules/dnn/src/tensorflow/tf_graph_simplifier.hpp

@@ -23,6 +23,8 @@ void simplifySubgraphs(tensorflow::GraphDef& net);
 
 Mat getTensorContent(const tensorflow::TensorProto &tensor);
 
+void releaseTensor(tensorflow::TensorProto* tensor);
+
 CV__DNN_EXPERIMENTAL_NS_END
 }}  // namespace dnn, namespace cv
 

modules/dnn/src/tensorflow/tf_importer.cpp

@@ -677,7 +677,9 @@ void TFImporter::populateNet(Net dstNet)
                 layers_to_ignore.insert(next_layers[0].first);
             }
 
-            kernelFromTensor(getConstBlob(layer, value_id), layerParams.blobs[0]);
+            const tensorflow::TensorProto& kernelTensor = getConstBlob(layer, value_id);
+            kernelFromTensor(kernelTensor, layerParams.blobs[0]);
+            releaseTensor(const_cast<tensorflow::TensorProto*>(&kernelTensor));
             int* kshape = layerParams.blobs[0].size.p;
             if (type == "DepthwiseConv2dNative")
             {
@@ -788,7 +790,9 @@ void TFImporter::populateNet(Net dstNet)
             }
 
             int kernel_blob_index = -1;
-            blobFromTensor(getConstBlob(layer, value_id, -1, &kernel_blob_index), layerParams.blobs[0]);
+            const tensorflow::TensorProto& kernelTensor = getConstBlob(layer, value_id, -1, &kernel_blob_index);
+            blobFromTensor(kernelTensor, layerParams.blobs[0]);
+            releaseTensor(const_cast<tensorflow::TensorProto*>(&kernelTensor));
 
             if (kernel_blob_index == 1) { // In this case output is computed by x*W formula - W should be transposed
                 Mat data = layerParams.blobs[0].t();