4 files changed, 90 insertions, 3 deletions

diff --git a/src/armnnSerializer/ArmnnSchema.fbs b/src/armnnSerializer/ArmnnSchema.fbs
index 09187927ae..e3953df83e 100644
--- a/src/armnnSerializer/ArmnnSchema.fbs
+++ b/src/armnnSerializer/ArmnnSchema.fbs
@@ -130,7 +130,8 @@ enum LayerType : uint {
     SpaceToDepth = 40,
     Prelu = 41,
     TransposeConvolution2d = 42,
-    Resize = 43
+    Resize = 43,
+    Stack = 44
 }
 
 // Base layer table to be used as part of other layers
@@ -599,6 +600,17 @@ table ResizeDescriptor {
     dataLayout:DataLayout;
 }
 
+table StackLayer {
+    base:LayerBase;
+    descriptor:StackDescriptor;
+}
+
+table StackDescriptor {
+    axis:uint;
+    numInputs:uint;
+    inputShape:[uint];
+}
+
 union Layer {
     ActivationLayer,
     AdditionLayer,
@@ -643,7 +655,8 @@ union Layer {
     SpaceToDepthLayer,
     PreluLayer,
     TransposeConvolution2dLayer,
-    ResizeLayer
+    ResizeLayer,
+    StackLayer
 }
 
 table AnyLayer {
diff --git a/src/armnnSerializer/Serializer.cpp b/src/armnnSerializer/Serializer.cpp
index 0a9e3353d7..b59bac6041 100644
--- a/src/armnnSerializer/Serializer.cpp
+++ b/src/armnnSerializer/Serializer.cpp
@@ -929,7 +929,21 @@ void SerializerVisitor::VisitStackLayer(const armnn::IConnectableLayer* layer,
                                         const armnn::StackDescriptor& stackDescriptor,
                                         const char* name)
 {
-    throw UnimplementedException("SerializerVisitor::VisitStackLayer not yet implemented");
+    auto stackBaseLayer = CreateLayerBase(layer, serializer::LayerType::LayerType_Stack);
+
+    std::vector<unsigned int> inputShape;
+    for (unsigned int i =0; i < stackDescriptor.m_InputShape.GetNumDimensions(); i++)
+    {
+        inputShape.push_back(stackDescriptor.m_InputShape[i]);
+    }
+
+    auto flatBufferStackDescriptor = CreateStackDescriptor(m_flatBufferBuilder,
+                                                           stackDescriptor.m_Axis,
+                                                           stackDescriptor.m_NumInputs,
+                                                           m_flatBufferBuilder.CreateVector(inputShape));
+
+    auto stackLayer = serializer::CreateStackLayer(m_flatBufferBuilder, stackBaseLayer, flatBufferStackDescriptor);
+    CreateAnyLayer(stackLayer.o, serializer::Layer::Layer_StackLayer);
 }
 
 void SerializerVisitor::VisitStridedSliceLayer(const armnn::IConnectableLayer* layer,
diff --git a/src/armnnSerializer/SerializerSupport.md b/src/armnnSerializer/SerializerSupport.md
index 924bab423f..1d47399376 100644
--- a/src/armnnSerializer/SerializerSupport.md
+++ b/src/armnnSerializer/SerializerSupport.md
@@ -42,6 +42,7 @@ The Arm NN SDK Serializer currently supports the following layers:
 * SpaceToBatchNd
 * SpaceToDepth
 * Splitter
+* Stack
 * StridedSlice
 * Subtraction
 * Switch
diff --git a/src/armnnSerializer/test/SerializerTests.cpp b/src/armnnSerializer/test/SerializerTests.cpp
index 33f10ef435..3d74d88e30 100644
--- a/src/armnnSerializer/test/SerializerTests.cpp
+++ b/src/armnnSerializer/test/SerializerTests.cpp
@@ -2379,6 +2379,65 @@ BOOST_AUTO_TEST_CASE(SerializeSplitter)
     deserializedNetwork->Accept(verifier);
 }
 
+BOOST_AUTO_TEST_CASE(SerializeStack)
+{
+    class StackLayerVerifier : public LayerVerifierBase
+    {
+    public:
+        StackLayerVerifier(const std::string& layerName,
+                           const std::vector<armnn::TensorInfo>& inputInfos,
+                           const std::vector<armnn::TensorInfo>& outputInfos,
+                           const armnn::StackDescriptor& descriptor)
+            : LayerVerifierBase(layerName, inputInfos, outputInfos)
+            , m_Descriptor(descriptor) {}
+
+        void VisitStackLayer(const armnn::IConnectableLayer* layer,
+                             const armnn::StackDescriptor& descriptor,
+                             const char* name) override
+        {
+            VerifyNameAndConnections(layer, name);
+            VerifyDescriptor(descriptor);
+        }
+
+    private:
+        void VerifyDescriptor(const armnn::StackDescriptor& descriptor)
+        {
+            BOOST_TEST(descriptor.m_Axis == m_Descriptor.m_Axis);
+            BOOST_TEST(descriptor.m_InputShape == m_Descriptor.m_InputShape);
+            BOOST_TEST(descriptor.m_NumInputs == m_Descriptor.m_NumInputs);
+        }
+
+        armnn::StackDescriptor m_Descriptor;
+    };
+
+    const std::string layerName("stack");
+
+    armnn::TensorInfo inputTensorInfo ({4, 3, 5}, armnn::DataType::Float32);
+    armnn::TensorInfo outputTensorInfo({4, 3, 2, 5}, armnn::DataType::Float32);
+
+    armnn::StackDescriptor descriptor(2, 2, {4, 3, 5});
+
+    armnn::INetworkPtr network = armnn::INetwork::Create();
+    armnn::IConnectableLayer* const inputLayer1 = network->AddInputLayer(0);
+    armnn::IConnectableLayer* const inputLayer2 = network->AddInputLayer(1);
+    armnn::IConnectableLayer* const stackLayer = network->AddStackLayer(descriptor, layerName.c_str());
+    armnn::IConnectableLayer* const outputLayer = network->AddOutputLayer(0);
+
+    inputLayer1->GetOutputSlot(0).Connect(stackLayer->GetInputSlot(0));
+    inputLayer2->GetOutputSlot(0).Connect(stackLayer->GetInputSlot(1));
+    stackLayer->GetOutputSlot(0).Connect(outputLayer->GetInputSlot(0));
+
+    inputLayer1->GetOutputSlot(0).SetTensorInfo(inputTensorInfo);
+    inputLayer2->GetOutputSlot(0).SetTensorInfo(inputTensorInfo);
+    stackLayer->GetOutputSlot(0).SetTensorInfo(outputTensorInfo);
+
+    armnn::INetworkPtr deserializedNetwork = DeserializeNetwork(SerializeNetwork(*network));
+    BOOST_CHECK(deserializedNetwork);
+
+    StackLayerVerifier verifier(layerName, {inputTensorInfo, inputTensorInfo}, {outputTensorInfo}, descriptor);
+    deserializedNetwork->Accept(verifier);
+}
+
 BOOST_AUTO_TEST_CASE(SerializeStridedSlice)
 {
     class StridedSliceLayerVerifier : public LayerVerifierBase