IVGCVSW-2508 Add no-op factory implementations and layer for Gather operator

 * Added GatherQueueDescriptor to WorkloadData
 * Added CreateGather function in WorkloadFactory.hpp
 * Added stub implementation of the CreateGreater function in workload factories
 * Added GatherLayer stub implementation
 * Added AddGatherLayer to Network
 * Added IsGatherSupported to LayerSupportBase

Change-Id: I0408fd54e88a7d4e3d9e1c2811a9323f0da52a04

8 files changed, 99 insertions, 0 deletions

diff --git a/src/armnn/InternalTypes.cpp b/src/armnn/InternalTypes.cpp
index 16a19722df..15f4aa07e2 100644
--- a/src/armnn/InternalTypes.cpp
+++ b/src/armnn/InternalTypes.cpp
@@ -29,6 +29,7 @@ char const* GetLayerTypeAsCString(LayerType type)
         case LayerType::FakeQuantization: return "FakeQuantization";
         case LayerType::Floor: return "Floor";
         case LayerType::FullyConnected: return "FullyConnected";
+        case LayerType::Gather: return "Gather";
         case LayerType::Greater: return "Greater";
         case LayerType::Input: return "Input";
         case LayerType::L2Normalization: return "L2Normalization";
diff --git a/src/armnn/InternalTypes.hpp b/src/armnn/InternalTypes.hpp
index f05ea25597..704efdf2b7 100644
--- a/src/armnn/InternalTypes.hpp
+++ b/src/armnn/InternalTypes.hpp
@@ -29,6 +29,7 @@ enum class LayerType
     FakeQuantization,
     Floor,
     FullyConnected,
+    Gather,
     Greater,
     Input,
     L2Normalization,
diff --git a/src/armnn/LayerSupport.cpp b/src/armnn/LayerSupport.cpp
index b0b3eccb02..b600e4daa9 100644
--- a/src/armnn/LayerSupport.cpp
+++ b/src/armnn/LayerSupport.cpp
@@ -245,6 +245,16 @@ bool IsFullyConnectedSupported(const BackendId& backend,
     FORWARD_LAYER_SUPPORT_FUNC(backend, IsFullyConnectedSupported, input, output, weights, biases, descriptor);
 }
 
+bool IsGatherSupported(const BackendId& backend,
+                       const TensorInfo& input0,
+                       const TensorInfo& input1,
+                       const TensorInfo& output,
+                       char* reasonIfUnsupported,
+                       size_t reasonIfUnsupportedMaxLength)
+{
+    FORWARD_LAYER_SUPPORT_FUNC(backend, IsGatherSupported, input0, input1, output);
+}
+
 bool IsGreaterSupported(const BackendId& backend,
                         const TensorInfo& input0,
                         const TensorInfo& input1,
diff --git a/src/armnn/LayersFwd.hpp b/src/armnn/LayersFwd.hpp
index 8b4ee0804b..27806c5752 100644
--- a/src/armnn/LayersFwd.hpp
+++ b/src/armnn/LayersFwd.hpp
@@ -21,6 +21,7 @@
 #include "layers/FakeQuantizationLayer.hpp"
 #include "layers/FloorLayer.hpp"
 #include "layers/FullyConnectedLayer.hpp"
+#include "layers/GatherLayer.hpp"
 #include "layers/GreaterLayer.hpp"
 #include "layers/InputLayer.hpp"
 #include "layers/L2NormalizationLayer.hpp"
@@ -88,6 +89,7 @@ DECLARE_LAYER(Equal)
 DECLARE_LAYER(FakeQuantization)
 DECLARE_LAYER(Floor)
 DECLARE_LAYER(FullyConnected)
+DECLARE_LAYER(Gather)
 DECLARE_LAYER(Greater)
 DECLARE_LAYER(Input)
 DECLARE_LAYER(L2Normalization)
diff --git a/src/armnn/Network.cpp b/src/armnn/Network.cpp
index 7b9cb3db7f..8a1437a0fb 100644
--- a/src/armnn/Network.cpp
+++ b/src/armnn/Network.cpp
@@ -872,6 +872,11 @@ IConnectableLayer* Network::AddRsqrtLayer(const char * name)
     return m_Graph->AddLayer<RsqrtLayer>(name);
 }
 
+IConnectableLayer* Network::AddGatherLayer(const char* name)
+{
+    return m_Graph->AddLayer<GatherLayer>(name);
+}
+
 OptimizedNetwork::OptimizedNetwork(std::unique_ptr<Graph> graph)
     : m_Graph(std::move(graph))
 {
diff --git a/src/armnn/Network.hpp b/src/armnn/Network.hpp
index ba741e9af6..7690fafac0 100644
--- a/src/armnn/Network.hpp
+++ b/src/armnn/Network.hpp
@@ -66,6 +66,8 @@ public:
         const ConstTensor& biases,
         const char* name = nullptr) override;
 
+    IConnectableLayer* AddGatherLayer(const char* name = nullptr) override;
+
     IConnectableLayer* AddPermuteLayer(const PermuteDescriptor& permuteDescriptor,
                                        const char* name = nullptr) override;
 
diff --git a/src/armnn/layers/GatherLayer.cpp b/src/armnn/layers/GatherLayer.cpp
new file mode 100644
index 0000000000..2e5d011599
--- /dev/null
+++ b/src/armnn/layers/GatherLayer.cpp
@@ -0,0 +1,37 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#include "GatherLayer.hpp"
+#include "LayerCloneBase.hpp"
+
+#include <armnn/TypesUtils.hpp>
+#include <backendsCommon/WorkloadData.hpp>
+#include <backendsCommon/WorkloadFactory.hpp>
+
+namespace armnn
+{
+
+GatherLayer::GatherLayer(const char* name)
+    : Layer(2, 1, LayerType::Gather, name)
+{
+}
+
+std::unique_ptr<IWorkload> GatherLayer::CreateWorkload(const armnn::Graph& graph,
+                                                       const armnn::IWorkloadFactory& factory) const
+{
+    GatherQueueDescriptor descriptor;
+    return factory.CreateGather(descriptor, PrepInfoAndDesc(descriptor, graph));
+}
+
+GatherLayer* GatherLayer::Clone(Graph& graph) const
+{
+    return CloneBase<GatherLayer>(graph, GetName());
+}
+
+void GatherLayer::ValidateTensorShapesFromInputs()
+{
+}
+
+} // namespace armnn
diff --git a/src/armnn/layers/GatherLayer.hpp b/src/armnn/layers/GatherLayer.hpp
new file mode 100644
index 0000000000..7b3aebe77e
--- /dev/null
+++ b/src/armnn/layers/GatherLayer.hpp
@@ -0,0 +1,41 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#pragma once
+
+#include "Layer.hpp"
+
+namespace armnn
+{
+
+/// This layer represents a Gather operator.
+class GatherLayer : public Layer
+{
+public:
+    /// Makes a workload for the Gather type.
+    /// @param [in] graph The graph where this layer can be found.
+    /// @param [in] factory The workload factory which will create the workload.
+    /// @return A pointer to the created workload, or nullptr if not created.
+    virtual std::unique_ptr<IWorkload> CreateWorkload(const Graph& graph,
+                                                      const IWorkloadFactory& factory) const override;
+
+    /// Creates a dynamically-allocated copy of this layer.
+    /// @param [in] graph The graph into which this layer is being cloned.
+    GatherLayer* Clone(Graph& graph) const override;
+
+    /// Check if the input tensor shape(s)
+    /// will lead to a valid configuration of @ref GatherLayer.
+    void ValidateTensorShapesFromInputs() override;
+
+protected:
+    /// Constructor to create a GatherLayer.
+    /// @param [in] name Optional name for the layer.
+    GatherLayer(const char* name);
+
+    /// Default destructor
+    ~GatherLayer() = default;
+};
+
+} // namespace armnn