IVGCVSW-1806: Refactor Android-NN-Driver ModelToINetworkConverter

* Moved conversion logic into new V1_0 and V1_1 HalPolicy classes
* Extracted common helper functions into ConversionUtils class

Change-Id: I1ab50edc266dd528c0cb22a5cd1aa65e103674d9
diff --git a/ConversionUtils.hpp b/ConversionUtils.hpp
new file mode 100644
index 0000000..a812183
--- /dev/null
+++ b/ConversionUtils.hpp
@@ -0,0 +1,1039 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#pragma once
+
+#include <armnn/ArmNN.hpp>
+
+#include "armnn/src/armnnUtils/Permute.hpp"
+#include "Utils.hpp"
+
+#include <ActivationFunctor.h>
+#include <CpuExecutor.h>
+#include <OperationsUtils.h>
+
+#include <boost/assert.hpp>
+#include <boost/core/ignore_unused.hpp>
+#include <boost/test/tools/floating_point_comparison.hpp>
+
+#include <log/log.h>
+
+namespace armnn_driver
+{
+
+///
+/// Helper classes
+///
+
+struct ConversionData
+{
+    ConversionData(armnn::Compute compute)
+            : m_Compute(compute)
+            , m_Network(nullptr, nullptr)
+    {}
+
+    const armnn::Compute                      m_Compute;
+    armnn::INetworkPtr                        m_Network;
+    std::vector<armnn::IOutputSlot*>          m_OutputSlotForOperand;
+    std::vector<android::nn::RunTimePoolInfo> m_MemPools;
+};
+
+class LayerInputHandle
+{
+public:
+    LayerInputHandle();
+    LayerInputHandle(bool valid, armnn::IOutputSlot* outputSlot, armnn::TensorInfo tensorInfo);
+
+    bool IsValid() const;
+
+    void Connect(armnn::IInputSlot& inputSlot);
+
+    const armnn::TensorInfo& GetTensorInfo() const;
+
+private:
+    armnn::IOutputSlot* m_OutputSlot;
+    bool                m_Valid;
+    armnn::TensorInfo   m_TensorInfo;
+};
+
+class ConstTensorPin
+{
+public:
+    // Creates an invalid tensor pin (can be used to signal errors)
+    // The optional flag can be set to indicate the tensor values were missing, but it was otherwise valid
+    ConstTensorPin(bool optional = false);
+
+    // @param tensorInfo TensorInfo associated with the tensor.
+    // @param valueStart Start address of tensor data. Belongs to one of the memory pools associated with
+    // the model being converted.
+    // @param numBytes Number of bytes for the tensor data.
+    ConstTensorPin(const armnn::TensorInfo& tensorInfo, const void* valueStart, uint32_t numBytes,
+                   const armnn::PermutationVector& mappings);
+
+    ConstTensorPin(const ConstTensorPin& other) = delete;
+    ConstTensorPin(ConstTensorPin&& other)      = default;
+
+    bool IsValid() const;
+    bool IsOptional() const;
+
+    const armnn::ConstTensor& GetConstTensor() const;
+    const armnn::ConstTensor* GetConstTensorPtr() const;
+
+private:
+    armnn::ConstTensor m_ConstTensor;
+
+    // Owned memory for swizzled tensor data, only required if the tensor needed
+    // swizzling. Otherwise, @ref m_ConstTensor will reference memory from one of
+    // the pools associated with the model being converted.
+    std::vector<uint8_t> m_SwizzledTensorData;
+
+    // optional flag to indicate that an invalid tensor pin is not an error, but the optional values were not given
+    bool m_Optional;
+};
+
+} // namespace armnn_driver
+
+///
+/// Utility functions
+///
+
+namespace
+{
+
+using namespace armnn_driver;
+using namespace android::nn;
+
+// Convenience function to log the reason for failing to convert a model.
+// @return Always returns false (so that it can be used by callers as a quick way to signal an error and return)
+template<class... Args>
+static bool Fail(const char* formatStr, Args&&... args)
+{
+    ALOGD(formatStr, std::forward<Args>(args)...);
+    return false;
+}
+
+// Convenience function to call an Is*Supported function and log caller name together with reason for lack of support.
+// Called as: IsLayerSupported(__func__, Is*Supported, a, b, c, d, e)
+template<typename IsLayerSupportedFunc, typename ... Args>
+bool IsLayerSupported(const char* funcName, IsLayerSupportedFunc f, Args&&... args)
+{
+    std::vector<char> unsupportedReason(1024+1);
+    bool isSupported = f(std::forward<Args>(args)..., unsupportedReason.data(), unsupportedReason.size()-1);
+    if(isSupported)
+    {
+        return true;
+    }
+    else
+    {
+        std::string sUnsupportedReason(unsupportedReason.data());
+        if (sUnsupportedReason.size() > 0)
+        {
+            ALOGD("%s: not supported by armnn: %s", funcName, sUnsupportedReason.c_str());
+        } else
+        {
+            ALOGD("%s: not supported by armnn", funcName);
+        }
+        return false;
+    }
+}
+
+armnn::TensorShape GetTensorShapeForOperand(const Operand& operand)
+{
+    return armnn::TensorShape(operand.dimensions.size(), operand.dimensions.data());
+}
+
+inline bool IsOperandTypeSupportedForTensors(OperandType type)
+{
+    return type == OperandType::TENSOR_FLOAT32      ||
+           type == OperandType::TENSOR_QUANT8_ASYMM ||
+           type == OperandType::TENSOR_INT32;
+}
+
+void BroadcastTensor(LayerInputHandle& input0, LayerInputHandle& input1, armnn::IConnectableLayer* startLayer,
+                     armnn::INetwork& network)
+{
+    BOOST_ASSERT(startLayer != nullptr);
+    const armnn::TensorInfo& inputTensorInfo0 = input0.GetTensorInfo();
+    const armnn::TensorInfo& inputTensorInfo1 = input1.GetTensorInfo();
+
+    if (inputTensorInfo0.GetNumDimensions() != inputTensorInfo1.GetNumDimensions())
+    {
+        // If the number of dimensions do not match then we need to add degenerate dimensions
+        // to the "smaller" tensor using a reshape:
+        //   Small  Big
+        //     |     |
+        //  Reshape  |
+        //      \   /
+        //       Add
+        bool input0IsBigger = inputTensorInfo0.GetNumDimensions() > inputTensorInfo1.GetNumDimensions();
+
+        LayerInputHandle& smallTensorHandle = input0IsBigger ? input1 : input0;
+        const armnn::TensorInfo& smallTensorDims = smallTensorHandle.GetTensorInfo();
+
+        LayerInputHandle& bigTensorHandle =  input0IsBigger ? input0 : input1;
+        const armnn::TensorInfo& bigTensorDims = bigTensorHandle.GetTensorInfo();
+
+        const unsigned int bigTensorDimsNumber = bigTensorDims.GetNumDimensions();
+        std::vector<unsigned int> reshapedDims(bigTensorDimsNumber, 1);
+        unsigned int sizeDifference = bigTensorDimsNumber - smallTensorDims.GetNumDimensions();
+        for (unsigned i = sizeDifference; i < bigTensorDimsNumber; ++i)
+        {
+            reshapedDims[i] = smallTensorDims.GetShape()[i-sizeDifference];
+        }
+        armnn::TensorInfo reshapedInfo = smallTensorDims;
+        reshapedInfo.SetShape(armnn::TensorShape{ static_cast<unsigned int>(reshapedDims.size()),
+                                                  reshapedDims.data() });
+
+        armnn::ReshapeDescriptor reshapeDesc;
+        reshapeDesc.m_TargetShape = reshapedInfo.GetShape();
+        armnn::IConnectableLayer* const reshapeLayer = network.AddReshapeLayer(reshapeDesc);
+        smallTensorHandle.Connect(reshapeLayer->GetInputSlot(0));
+        reshapeLayer->GetOutputSlot(0).SetTensorInfo(reshapedInfo);
+
+        // Connect the outputs from new reshape and original input layer
+        reshapeLayer->GetOutputSlot(0).Connect(startLayer->GetInputSlot(0));
+        bigTensorHandle.Connect(startLayer->GetInputSlot(1));
+    }
+    else
+    {
+        input0.Connect(startLayer->GetInputSlot(0));
+        input1.Connect(startLayer->GetInputSlot(1));
+    }
+}
+
+void CalcPadding(uint32_t input, uint32_t kernel, uint32_t stride, uint32_t& outPadHead, uint32_t& outPadTail,
+                 android::nn::PaddingScheme scheme)
+{
+    int32_t padHead;
+    int32_t padTail;
+    calculateExplicitPadding(input, stride, kernel, scheme, &padHead, &padTail);
+    outPadHead = boost::numeric_cast<uint32_t>(padHead);
+    outPadTail = boost::numeric_cast<uint32_t>(padTail);
+}
+
+Shape GetOperandShape(const Operand& operand)
+{
+    Shape shape;
+    shape.type = operand.type;
+    shape.dimensions = operand.dimensions;
+    shape.scale = operand.scale;
+    shape.offset = operand.zeroPoint;
+    return shape;
+}
+
+// ArmNN requires the bias scale to be equal to the product of the weight and input scales, which is also
+// what AndroidNN requires. However for some of the AndroidNN tests the values don't exactly match so
+// we accept some tolerance. We don't want to ArmNN itself to accept these inconsistencies as it is up to the user
+// (us, in this case) to ensure they match.
+void SanitizeBiasQuantizationScale(armnn::TensorInfo& biasInfo,
+                                   const armnn::TensorInfo& weightInfo, const armnn::TensorInfo& inputInfo)
+{
+    const float expectedBiasScale = weightInfo.GetQuantizationScale() * inputInfo.GetQuantizationScale();
+    if (biasInfo.GetQuantizationScale() != expectedBiasScale)
+    {
+        boost::math::fpc::close_at_tolerance<float> comparer(boost::math::fpc::percent_tolerance(1.0f));
+        if (comparer(biasInfo.GetQuantizationScale(), expectedBiasScale))
+        {
+            ALOGW("Bias quantization scale has been modified to match input*weights");
+            biasInfo.SetQuantizationScale(expectedBiasScale);
+        }
+    }
+}
+
+// 4D Tensor Permutations
+const armnn::PermutationVector IdentityPermutation4D({ 0U, 1U, 2U, 3U });
+const armnn::PermutationVector NHWCToArmNN({ 0U, 2U, 3U, 1U });
+const armnn::PermutationVector ArmNNToNHWC({ 0U, 3U, 1U, 2U });
+const armnn::PermutationVector SwapDim1And2({ 0U, 2U, 1U, 3U });
+
+// 3D Permutation Vectors
+const armnn::PermutationVector IdentityPermutation3D({ 0U, 1U, 2U });
+const armnn::PermutationVector RotateTensorLeft({ 2U, 0U, 1U });
+const armnn::PermutationVector RotateTensorRight({ 1U, 2U, 0U });
+
+template<typename OSlot>
+armnn::IConnectableLayer& AddPermuteLayer(armnn::INetwork& network, OSlot& input,
+                                          const armnn::PermutationVector& mappings)
+{
+    // Add swizzle layer
+    armnn::IConnectableLayer* const layer = network.AddPermuteLayer(mappings);
+
+    BOOST_ASSERT(layer != nullptr);
+
+    // Connect input to swizzle layer
+    input.Connect(layer->GetInputSlot(0));
+
+    // Setup swizzled output
+    const armnn::TensorInfo outInfo = armnnUtils::Permuted(input.GetTensorInfo(), mappings);
+    layer->GetOutputSlot(0).SetTensorInfo(outInfo);
+
+    return *layer;
+}
+
+void SwizzleIn(armnn::INetwork& network, LayerInputHandle& input, armnn::IConnectableLayer& layer, unsigned int index)
+{
+    // Add swizzle layer
+    armnn::IConnectableLayer& swizzleLayer = AddPermuteLayer(network, input, NHWCToArmNN);
+    // Connect swizzled input to layer
+    swizzleLayer.GetOutputSlot(0).Connect(layer.GetInputSlot(index));
+}
+
+armnn::IConnectableLayer& DeswizzleOut(armnn::INetwork& network, armnn::IConnectableLayer& layer, unsigned int index)
+{
+    // Add deswizzle layer
+    armnn::IConnectableLayer& deswizzleLayer = AddPermuteLayer(network, layer.GetOutputSlot(index), ArmNNToNHWC);
+    return deswizzleLayer;
+}
+
+// only suitable for input/output slot index 0, for other slots, use SwizzleIn and DeswizzleOut directly
+armnn::IConnectableLayer& SwizzleInDeswizzleOut(armnn::INetwork& network,
+                                                LayerInputHandle& input,
+                                                armnn::IConnectableLayer& firstLayer,
+                                                armnn::IConnectableLayer& lastLayer)
+{
+    SwizzleIn(network, input, firstLayer, 0);
+    return DeswizzleOut(network, lastLayer, 0);
+}
+
+// only suitable for input/output slot index 0, for other slots, use SwizzleIn and DeswizzleOut directly
+armnn::IConnectableLayer& SwizzleInDeswizzleOut(armnn::INetwork& network, LayerInputHandle& input,
+                                                armnn::IConnectableLayer& layer)
+{
+    return SwizzleInDeswizzleOut(network, input, layer, layer);
+}
+
+bool ValidateConcatOutputShape(const std::vector<armnn::TensorShape> & inputShapes,
+                               const armnn::TensorShape & outputShape,
+                               uint32_t concatDim)
+{
+    // Validate the output shape is correct given the input shapes (which have just been validated)
+    unsigned int numDimensions = inputShapes[0].GetNumDimensions();
+    if (outputShape.GetNumDimensions() != numDimensions)
+    {
+        return Fail("%s: Output shape has wrong number of dimensions", __func__);
+    }
+
+    unsigned int outputSizeAlongConcatenatedDimension = 0;
+    for (unsigned int i = 0; i < inputShapes.size(); i++)
+    {
+        outputSizeAlongConcatenatedDimension += inputShapes[i][concatDim];
+    }
+
+    for (unsigned int i = 0; i < numDimensions; ++i)
+    {
+        if (i == concatDim)
+        {
+            if (outputShape[i] != outputSizeAlongConcatenatedDimension)
+            {
+                return Fail(
+                        "%s: Invalid output shape for dimension %d (%d != %d)",
+                        __func__,
+                        i,
+                        outputShape[i],
+                        outputSizeAlongConcatenatedDimension);
+            }
+        }
+        else
+        {
+            if (outputShape[i] != inputShapes[0][i])
+            {
+                return Fail("%s: Invalid output shape", __func__);
+            }
+        }
+    }
+
+    return true;
+}
+
+bool RequiresReshape(armnn::TensorShape & inputShape)
+{
+    return inputShape.GetNumDimensions() < 3;
+}
+
+template<typename OSlot>
+armnn::IConnectableLayer& AddReshapeLayer(armnn::INetwork& network, OSlot& inputLayer,
+                                          armnn::TensorInfo reshapeInfo)
+{
+    armnn::ReshapeDescriptor reshapeDescriptor;
+    reshapeDescriptor.m_TargetShape = reshapeInfo.GetShape();
+
+    armnn::IConnectableLayer* reshapeLayer = network.AddReshapeLayer(reshapeDescriptor);
+    BOOST_ASSERT(reshapeLayer != nullptr);
+
+    // Attach the input layer to the reshape layer
+    inputLayer.Connect(reshapeLayer->GetInputSlot(0));
+    reshapeLayer->GetOutputSlot(0).SetTensorInfo(reshapeInfo);
+
+    return *reshapeLayer;
+}
+
+void SwizzleInputs(armnn::INetwork& network,
+                   std::vector<LayerInputHandle>& inputs,
+                   std::vector<armnn::TensorShape>& inputShapes,
+                   const armnn::PermutationVector& mapping)
+{
+    if (!mapping.IsEqual(IdentityPermutation4D))
+    {
+        size_t nInputs = inputs.size();
+        for (size_t i=0; i<nInputs; ++i)
+        {
+            // add swizzle layer
+            armnn::IConnectableLayer& swizzleLayer = AddPermuteLayer(network, inputs[i], mapping);
+            auto& outputSlot = swizzleLayer.GetOutputSlot(0);
+            auto& outputInfo = outputSlot.GetTensorInfo();
+            // replace inputs with the swizzled ones
+            inputs[i] = LayerInputHandle(true, &outputSlot, outputInfo);
+            inputShapes[i] = inputs[i].GetTensorInfo().GetShape();
+        }
+    }
+}
+
+void CreatePermutationParameters(const unsigned int numberOfDimensions,
+                                 int32_t & concatDimension,
+                                 std::pair<armnn::PermutationVector, armnn::PermutationVector> & permutationPair)
+{
+    BOOST_ASSERT(numberOfDimensions >= 3);
+
+    // ArmNN uses Compute Library subtensors to perform concatenation
+    // This only works when concatenating along dimension 0 or 1 for a 4-D tensor,
+    // or along dimension 0 for a 3-D tensor.
+    if (numberOfDimensions == 4)
+    {
+        if (concatDimension == 3)
+        {
+            concatDimension = 1;
+            permutationPair = std::make_pair(NHWCToArmNN, ArmNNToNHWC);
+        }
+        else if (concatDimension == 2)
+        {
+            concatDimension = 1;
+            permutationPair = std::make_pair(SwapDim1And2, SwapDim1And2);
+        }
+        else
+        {
+            permutationPair = std::make_pair(IdentityPermutation4D, IdentityPermutation4D);
+        }
+
+    }
+    else if (numberOfDimensions == 3)
+    {
+        if (concatDimension == 2)
+        {
+            concatDimension = 0;
+            permutationPair = std::make_pair(RotateTensorRight, RotateTensorLeft);
+        }
+        else if (concatDimension == 1)
+        {
+            concatDimension = 0;
+            permutationPair = std::make_pair(RotateTensorLeft, RotateTensorRight);
+        }
+        else
+        {
+            permutationPair = std::make_pair(IdentityPermutation3D, IdentityPermutation3D);
+        }
+    }
+}
+
+} // anonymous namespace
+
+namespace armnn_driver
+{
+
+//// Creates an ArmNN activation layer and connects it to the given layer, if the
+//// passed in AndroidNN activation function requires so.
+//// @return The end layer of the sequence of layers built for the given AndroidNN
+//// activation function or nullptr if an error occurred (e.g. unsupported activation).
+//// Note that the end layer matches the input layer if no activation is required
+//// (the sequence of layers has length 1).
+armnn::IConnectableLayer* ProcessActivation(const armnn::TensorInfo& tensorInfo,
+                                            ActivationFn activation,
+                                            armnn::IConnectableLayer* prevLayer,
+                                            ConversionData& data);
+
+} // namespace armnn_driver
+
+///
+/// Utility templates
+///
+
+namespace armnn_driver
+{
+
+using namespace android::nn;
+
+template<typename HalOperation, typename HalModel>
+const Operand* GetInputOperand(const HalOperation& operation, uint32_t inputIndex, const HalModel& model)
+{
+    if (inputIndex >= operation.inputs.size())
+    {
+        Fail("%s: invalid input index: %i out of %i", __func__, inputIndex, operation.inputs.size());
+        return nullptr;
+    }
+
+    BOOST_ASSERT(operation.inputs[inputIndex] < model.operands.size()); // Model should have been validated beforehand
+    return &model.operands[operation.inputs[inputIndex]];
+}
+
+template<typename HalOperation, typename HalModel>
+const Operand* GetOutputOperand(const HalOperation& operation, uint32_t outputIndex, const HalModel& model)
+{
+    if (outputIndex >= operation.outputs.size())
+    {
+        Fail("%s: invalid output index: %i out of %i", __func__, outputIndex, operation.outputs.size());
+        return nullptr;
+    }
+
+    // Model should have been validated beforehand
+    BOOST_ASSERT(operation.outputs[outputIndex] < model.operands.size());
+
+    return &model.operands[operation.outputs[outputIndex]];
+}
+
+template<typename HalModel>
+ConstTensorPin ConvertOperandToConstTensorPin(const Operand& operand,
+                                              const HalModel& model,
+                                              const ConversionData& data,
+                                              const armnn::PermutationVector& dimensionMappings = g_DontPermute,
+                                              const armnn::TensorShape* overrideTensorShape = nullptr,
+                                              bool optional = false)
+{
+    if (!IsOperandTypeSupportedForTensors(operand.type))
+    {
+        Fail("%s: unsupported operand type for tensor %s", __func__, toString(operand.type).c_str());
+        return ConstTensorPin();
+    }
+
+    if (operand.lifetime != OperandLifeTime::CONSTANT_COPY && operand.lifetime != OperandLifeTime::CONSTANT_REFERENCE)
+    {
+        Fail("%s: invalid operand lifetime: %s", __func__, toString(operand.lifetime).c_str());
+        return ConstTensorPin();
+    }
+
+    const void* const valueStart = GetOperandValueReadOnlyAddress(operand, model, data);
+    if (!valueStart)
+    {
+        if (optional)
+        {
+            // optional tensor with no values is not really an error; return it as invalid, but marked as optional
+            return ConstTensorPin(true);
+        }
+        // mandatory tensor with no values
+        Fail("%s: failed to get operand address", __func__);
+        return ConstTensorPin();
+    }
+
+    armnn::TensorInfo tensorInfo = GetTensorInfoForOperand(operand);
+    if (overrideTensorShape != nullptr)
+    {
+        tensorInfo.SetShape(*overrideTensorShape);
+    }
+    return ConstTensorPin(tensorInfo, valueStart, operand.location.length, dimensionMappings);
+}
+
+template<typename HalOperation, typename HalModel>
+ConstTensorPin ConvertOperationInputToConstTensorPin(const HalOperation& operation,
+                                                     uint32_t inputIndex,
+                                                     const HalModel& model,
+                                                     const ConversionData& data,
+                                                     const armnn::PermutationVector& dimensionMappings = g_DontPermute,
+                                                     const armnn::TensorShape* overrideTensorShape = nullptr,
+                                                     bool optional = false)
+{
+    const Operand* operand = GetInputOperand(operation, inputIndex, model);
+    if (!operand)
+    {
+        Fail("%s: failed to get input operand: index=%u", __func__, inputIndex);
+        return ConstTensorPin();
+    }
+    return ConvertOperandToConstTensorPin(*operand,
+                                          model,
+                                          data,
+                                          dimensionMappings,
+                                          overrideTensorShape,
+                                          optional);
+}
+
+template<typename HalModel>
+const void* GetOperandValueReadOnlyAddress(const Operand& operand, const HalModel& model, const ConversionData& data)
+{
+    const void* valueStart = nullptr;
+
+    switch (operand.lifetime)
+    {
+        case OperandLifeTime::CONSTANT_COPY:
+        {
+            // Constant found in model.operandValues
+            valueStart = &model.operandValues[operand.location.offset];
+            break;
+        }
+        case OperandLifeTime::CONSTANT_REFERENCE:
+        {
+            // Constant specified via a Memory object
+            valueStart = GetMemoryFromPool(operand.location, data.m_MemPools);
+            break;
+        }
+        default:
+        {
+            // Unsupported/invalid (e.g. can't get value of an input to the model)
+            Fail("%s: unsupported/invalid operand lifetime: %s",
+                 __func__, toString(operand.lifetime).c_str());
+            valueStart = nullptr;
+        }
+    }
+
+    return valueStart;
+}
+
+template<typename HalOperation, typename HalModel, typename OutputType>
+bool GetInputScalar(const HalOperation& operation,
+                    uint32_t inputIndex,
+                    OperandType type,
+                    OutputType& outValue,
+                    const HalModel& model,
+                    const ConversionData& data)
+{
+    const Operand* operand = GetInputOperand(operation, inputIndex, model);
+    if (!operand)
+    {
+        return Fail("%s: invalid input operand at index %i", __func__, inputIndex);
+    }
+
+    if (operand->type != type)
+    {
+        return Fail("%s: unexpected operand type: %s (should be %s)",
+                    __func__, toString(operand->type).c_str(), toString(type).c_str());
+    }
+
+    if (operand->location.length != sizeof(OutputType))
+    {
+        return Fail("%s: incorrect operand location length: %i (should be %i)",
+                    __func__, operand->location.length, sizeof(OutputType));
+    }
+
+    const void* valueAddress = GetOperandValueReadOnlyAddress(*operand, model, data);
+    if (!valueAddress)
+    {
+        return Fail("%s: failed to get address for operand", __func__);
+    }
+
+    outValue = *(static_cast<const OutputType*>(valueAddress));
+    return true;
+}
+
+template<typename HalOperation, typename HalModel>
+bool GetInputInt32(const HalOperation& operation,
+                   uint32_t inputIndex,
+                   int32_t& outValue,
+                   const HalModel& model,
+                   const ConversionData& data)
+{
+    return GetInputScalar(operation, inputIndex, OperandType::INT32, outValue, model, data);
+}
+
+
+template<typename HalOperation, typename HalModel>
+bool GetInputFloat32(const HalOperation& operation,
+                     uint32_t inputIndex,
+                     float& outValue,
+                     const HalModel& model,
+                     const ConversionData& data)
+{
+    return GetInputScalar(operation, inputIndex, OperandType::FLOAT32, outValue, model, data);
+}
+
+
+template<typename HalOperation, typename HalModel>
+bool GetInputActivationFunctionImpl(const HalOperation& operation,
+                                    uint32_t inputIndex,
+                                    OperandType type,
+                                    ActivationFn& outActivationFunction,
+                                    const HalModel& model,
+                                    const ConversionData& data)
+{
+    if (type != OperandType::INT32 && type != OperandType::TENSOR_INT32)
+    {
+        return Fail("%s: unexpected operand type: %s (should be %s or %s)",
+                    __func__,
+                    toString(type).c_str(),
+                    toString(OperandType::INT32).c_str(),
+                    toString(OperandType::TENSOR_INT32).c_str());
+    }
+
+    int32_t activationFunctionAsInt;
+    if (!GetInputScalar(operation, inputIndex, type, activationFunctionAsInt, model, data))
+    {
+        return Fail("%s: failed to get activation input value", __func__);
+    }
+    outActivationFunction = static_cast<ActivationFn>(activationFunctionAsInt);
+    return true;
+}
+
+
+template<typename HalOperation, typename HalModel>
+bool GetInputActivationFunction(const HalOperation& operation,
+                                uint32_t inputIndex,
+                                ActivationFn& outActivationFunction,
+                                const HalModel& model,
+                                const ConversionData& data)
+{
+    return GetInputActivationFunctionImpl(operation,
+                                          inputIndex,
+                                          OperandType::INT32,
+                                          outActivationFunction,
+                                          model,
+                                          data);
+}
+
+template<typename HalOperation, typename HalModel>
+bool GetInputActivationFunctionFromTensor(const HalOperation& operation,
+                                          uint32_t inputIndex,
+                                          ActivationFn& outActivationFunction,
+                                          const HalModel& model,
+                                          const ConversionData& data)
+{
+    // This only accepts a 1-D tensor of size 1
+    return GetInputActivationFunctionImpl(operation,
+                                          inputIndex,
+                                          OperandType::INT32,
+                                          outActivationFunction,
+                                          model,
+                                          data);
+}
+
+
+template<typename HalOperation, typename HalModel>
+bool GetOptionalInputActivation(const HalOperation& operation,
+                                uint32_t inputIndex,
+                                ActivationFn& activationFunction,
+                                const HalModel& model,
+                                const ConversionData& data)
+{
+    if (operation.inputs.size() <= inputIndex)
+    {
+        activationFunction = ActivationFn::kActivationNone;
+    }
+    else
+    {
+        if (!GetInputActivationFunction(operation, inputIndex, activationFunction, model, data))
+        {
+            return Fail("%s: Operation has invalid inputs", __func__);
+        }
+    }
+    return true;
+}
+
+template<typename HalModel>
+bool GetTensorInt32Values(const Operand& operand,
+                          std::vector<int32_t>& outValues,
+                          const HalModel& model,
+                          const ConversionData& data)
+{
+    if (operand.type != OperandType::TENSOR_INT32)
+    {
+        return Fail("%s: invalid operand type: %s", __func__, toString(operand.type).c_str());
+    }
+
+    const void* startAddress = GetOperandValueReadOnlyAddress(operand, model, data);
+    if (!startAddress)
+    {
+        return Fail("%s: failed to get operand address", __func__, operand.type);
+    }
+
+    // Check number of bytes is sensible
+    const uint32_t numBytes = operand.location.length;
+    if (numBytes % sizeof(int32_t) != 0)
+    {
+        return Fail("%s: invalid number of bytes: %i, expected to be a multiple of %i",
+                    __func__, numBytes, sizeof(int32_t));
+    }
+
+    outValues.resize(numBytes / sizeof(int32_t));
+    memcpy(outValues.data(), startAddress, numBytes);
+    return true;
+}
+
+template<typename HalOperation, typename HalModel>
+bool GetInputPaddingScheme(const HalOperation& operation,
+                           uint32_t inputIndex,
+                           PaddingScheme& outPaddingScheme,
+                           const HalModel& model,
+                           const ConversionData& data)
+{
+    int32_t paddingSchemeAsInt;
+    if (!GetInputInt32(operation, inputIndex, paddingSchemeAsInt, model, data))
+    {
+        return Fail("%s: failed to get padding scheme input value", __func__);
+    }
+
+    outPaddingScheme = static_cast<android::nn::PaddingScheme>(paddingSchemeAsInt);
+    return true;
+}
+
+template<typename HalOperation, typename HalModel>
+LayerInputHandle ConvertToLayerInputHandle(const HalOperation& operation,
+                                           uint32_t inputIndex,
+                                           const HalModel& model,
+                                           ConversionData& data)
+{
+    const Operand* operand = GetInputOperand(operation, inputIndex, model);
+    if (!operand)
+    {
+        Fail("%s: failed to get input operand %i", __func__, inputIndex);
+        return LayerInputHandle();
+    }
+
+    if (!IsOperandTypeSupportedForTensors(operand->type))
+    {
+        Fail("%s: unsupported operand type for tensor %s", __func__, toString(operand->type).c_str());
+        return LayerInputHandle();
+    }
+
+    armnn::TensorInfo operandTensorInfo = GetTensorInfoForOperand(*operand);
+
+    switch (operand->lifetime)
+    {
+        case OperandLifeTime::TEMPORARY_VARIABLE: // intentional fallthrough
+        case OperandLifeTime::MODEL_INPUT:
+        {
+            // The tensor is either an operand internal to the model, or a model input.
+            // It can be associated with an ArmNN output slot for an existing layer.
+
+            // m_OutputSlotForOperand[...] can be nullptr if the previous layer could not be converted
+            const uint32_t operandIndex = operation.inputs[inputIndex];
+            return LayerInputHandle(true, data.m_OutputSlotForOperand[operandIndex], operandTensorInfo);
+            break;
+        }
+        case OperandLifeTime::CONSTANT_COPY:
+        case OperandLifeTime::CONSTANT_REFERENCE:
+        {
+            // The tensor has an already known constant value, and can be converted into an ArmNN Constant layer.
+            ConstTensorPin tensorPin = ConvertOperandToConstTensorPin(*operand, model, data);
+            if (tensorPin.IsValid())
+            {
+                if (!IsLayerSupported(__func__,
+                                      armnn::IsConstantSupported,
+                                      data.m_Compute,
+                                      tensorPin.GetConstTensor().GetInfo()))
+                {
+                    return LayerInputHandle();
+                }
+
+                armnn::IConnectableLayer* constantLayer = data.m_Network->AddConstantLayer(tensorPin.GetConstTensor());
+                armnn::IOutputSlot& outputSlot = constantLayer->GetOutputSlot(0);
+                outputSlot.SetTensorInfo(tensorPin.GetConstTensor().GetInfo());
+
+                return LayerInputHandle(true, &outputSlot, operandTensorInfo);
+            }
+            else
+            {
+                Fail("%s: invalid operand tensor", __func__);
+                return LayerInputHandle();
+            }
+            break;
+        }
+        default:
+        {
+            // Unsupported lifetime for an input tensor
+            Fail("%s: unsupported lifetime for input tensor: %s",
+                 __func__, toString(operand->lifetime).c_str());
+            return LayerInputHandle();
+        }
+    }
+}
+
+template<typename HalOperation, typename HalModel>
+bool ConvertToActivation(const HalOperation& operation,
+                         const char* operationName,
+                         const armnn::ActivationDescriptor& activationDesc,
+                         const HalModel& model,
+                         ConversionData& data)
+{
+    LayerInputHandle input = ConvertToLayerInputHandle(operation, 0, model, data);
+    if (!input.IsValid())
+    {
+        return Fail("%s: Input 0 is invalid", operationName);
+    }
+
+    const Operand* outputOperand = GetOutputOperand(operation, 0, model);
+    if (!outputOperand)
+    {
+        return false;
+    }
+    const armnn::TensorInfo outInfo = GetTensorInfoForOperand(*outputOperand);
+    if (!IsLayerSupported(__func__,
+                          armnn::IsActivationSupported,
+                          data.m_Compute,
+                          input.GetTensorInfo(),
+                          outInfo,
+                          activationDesc))
+    {
+        return false;
+    }
+
+    armnn::IConnectableLayer* layer = data.m_Network->AddActivationLayer(activationDesc);
+    BOOST_ASSERT(layer != nullptr);
+    input.Connect(layer->GetInputSlot(0));
+
+    return SetupAndTrackLayerOutputSlot(operation, 0, *layer, model, data);
+}
+
+template<typename HalOperation, typename HalModel>
+bool SetupAndTrackLayerOutputSlot(const HalOperation& operation,
+                                  uint32_t operationOutputIndex,
+                                  armnn::IConnectableLayer& layer,
+                                  uint32_t layerOutputIndex,
+                                  const HalModel& model,
+                                  ConversionData& data)
+{
+    const Operand* outputOperand = GetOutputOperand(operation, operationOutputIndex, model);
+    if ((outputOperand == nullptr) || (operationOutputIndex >= layer.GetNumOutputSlots()))
+    {
+        return false;
+    }
+
+    armnn::IOutputSlot& outputSlot = layer.GetOutputSlot(layerOutputIndex);
+
+    const uint32_t operandIndex = operation.outputs[operationOutputIndex];
+    data.m_OutputSlotForOperand[operandIndex] = &outputSlot;
+
+    outputSlot.SetTensorInfo(GetTensorInfoForOperand(*outputOperand));
+
+    return true;
+}
+
+template<typename HalOperation, typename HalModel>
+bool SetupAndTrackLayerOutputSlot(const HalOperation& operation,
+                                  uint32_t outputIndex,
+                                  armnn::IConnectableLayer& layer,
+                                  const HalModel& model,
+                                  ConversionData& data)
+{
+    return SetupAndTrackLayerOutputSlot(operation, outputIndex, layer, outputIndex, model, data);
+}
+
+template<typename HalOperation, typename HalModel>
+bool ConvertPooling2d(const HalOperation& operation,
+                      const char* operationName,
+                      armnn::PoolingAlgorithm poolType,
+                      const HalModel& model,
+                      ConversionData& data)
+{
+    LayerInputHandle input = ConvertToLayerInputHandle(operation, 0, model, data);
+    if (!input.IsValid())
+    {
+        return Fail("%s: Could not read input 0", operationName);
+    }
+
+    const Operand* output = GetOutputOperand(operation, 0, model);
+    if (!output)
+    {
+        return Fail("%s: Could not read output 0", __func__);
+    }
+
+    const armnn::TensorInfo& inputInfo  = input.GetTensorInfo();
+    const armnn::TensorInfo& outputInfo = GetTensorInfoForOperand(*output);
+
+    const armnn::TensorInfo swizzledInputInfo  = armnnUtils::Permuted(inputInfo, NHWCToArmNN);
+    const armnn::TensorInfo swizzledOutputInfo = armnnUtils::Permuted(outputInfo, NHWCToArmNN);
+
+    armnn::Pooling2dDescriptor desc;
+    desc.m_PoolType = poolType;
+    desc.m_OutputShapeRounding = armnn::OutputShapeRounding::Floor;
+
+    ActivationFn activation;
+
+    if (operation.inputs.size() == 7)
+    {
+        // one input, 6 parameters (padding, stridex, stridey, width, height, activation type)
+        android::nn::PaddingScheme scheme;
+        if (!GetInputPaddingScheme(operation, 1, scheme, model, data)
+            || !GetInputScalar(operation, 2, OperandType::INT32, desc.m_StrideX, model, data)
+            || !GetInputScalar(operation, 3, OperandType::INT32, desc.m_StrideY, model, data)
+            || !GetInputScalar(operation, 4, OperandType::INT32, desc.m_PoolWidth, model, data)
+            || !GetInputScalar(operation, 5, OperandType::INT32, desc.m_PoolHeight, model, data)
+            || !GetInputActivationFunction(operation, 6, activation, model, data))
+        {
+            return Fail("%s: Operation has invalid inputs", operationName);
+        }
+
+        const unsigned int inputWidth  = swizzledInputInfo.GetShape()[3];
+        const unsigned int inputHeight = swizzledInputInfo.GetShape()[2];
+
+        CalcPadding(inputWidth, desc.m_PoolWidth, desc.m_StrideX, desc.m_PadLeft, desc.m_PadRight, scheme);
+        CalcPadding(inputHeight, desc.m_PoolHeight, desc.m_StrideY, desc.m_PadTop, desc.m_PadBottom, scheme);
+    }
+    else
+    {
+        // one input, 9 parameters (padding l r t b, stridex, stridey, width, height, activation type)
+        if (!GetInputScalar(operation, 1, OperandType::INT32, desc.m_PadLeft, model, data)
+            || !GetInputScalar(operation, 2, OperandType::INT32, desc.m_PadRight, model, data)
+            || !GetInputScalar(operation, 3, OperandType::INT32, desc.m_PadTop, model, data)
+            || !GetInputScalar(operation, 4, OperandType::INT32, desc.m_PadBottom, model, data)
+            || !GetInputScalar(operation, 5, OperandType::INT32, desc.m_StrideX, model, data)
+            || !GetInputScalar(operation, 6, OperandType::INT32, desc.m_StrideY, model, data)
+            || !GetInputScalar(operation, 7, OperandType::INT32, desc.m_PoolWidth, model, data)
+            || !GetInputScalar(operation, 8, OperandType::INT32, desc.m_PoolHeight, model, data)
+            || !GetInputActivationFunction(operation, 9, activation, model, data))
+        {
+            return Fail("%s: Operation has invalid inputs", operationName);
+        }
+    }
+
+    // ArmNN does not accept a pool size of 1, but the ArmNN driver is expected to cope.
+    // This is mapped to a trivial splitter instead.
+    armnn::IConnectableLayer* startLayer = nullptr;
+    if (desc.m_PoolWidth != 1 || desc.m_PoolHeight != 1)
+    {
+        if (!IsLayerSupported(__func__,
+                              armnn::IsPooling2dSupported,
+                              data.m_Compute,
+                              swizzledInputInfo,
+                              swizzledOutputInfo,
+                              desc))
+        {
+            return false;
+        }
+
+        startLayer = data.m_Network->AddPooling2dLayer(desc);
+    }
+    else
+    {
+        const unsigned int numDims = swizzledOutputInfo.GetNumDimensions();
+
+        armnn::ViewsDescriptor viewsDesc(1, numDims);
+
+        for (unsigned int i = 0; i < numDims; ++i)
+        {
+            viewsDesc.SetViewOriginCoord(0, i, 0);
+            viewsDesc.SetViewSize(0, i, swizzledOutputInfo.GetShape()[i]);
+        }
+
+        if (!IsLayerSupported(__func__,
+                              armnn::IsSplitterSupported,
+                              data.m_Compute,
+                              swizzledInputInfo,
+                              viewsDesc))
+        {
+            return false;
+        }
+
+        startLayer = data.m_Network->AddSplitterLayer(viewsDesc);
+    }
+
+    armnn::IConnectableLayer* endLayer = ProcessActivation(swizzledOutputInfo, activation, startLayer, data);
+
+    if (endLayer != nullptr)
+    {
+        armnn::IConnectableLayer& outSwizzleLayer =
+                SwizzleInDeswizzleOut(*data.m_Network, input, *startLayer, *endLayer);
+        return SetupAndTrackLayerOutputSlot(operation, 0, outSwizzleLayer, model, data);
+    }
+    else
+    {
+        return Fail("%s: ProcessActivation failed", operationName);
+    }
+}
+
+} // namespace armnn_driver
\ No newline at end of file