IVGCVSW-7501 Allow constant tensors as inputs for input data in the delegate

 In the TLCT tests we were failing many tests because they used
 constant tensors as data input for the layers. We had the functionality
 in place but we didnt have it spread across the visit functions.

 * Check if inputs are constant tensors and attempt to assign them
   to input slot of layers.
 * Add missing checks to some functions that return a kTfLiteStatus
   so we can see if they fail
 * Clean up CreateConstTensor function

Signed-off-by: Ryan OShea <ryan.oshea3@arm.com>
Change-Id: I8610b770aea56932a98f91c961d59b3de47c2ab5

1 files changed, 23 insertions, 12 deletions

diff --git a/delegate/src/FullyConnected.hpp b/delegate/src/FullyConnected.hpp
index 337f1153a1..1129951104 100644
--- a/delegate/src/FullyConnected.hpp
+++ b/delegate/src/FullyConnected.hpp
@@ -54,7 +54,7 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
     }
 
     const armnn::TensorInfo& inputTensorInfo  = GetTensorInfoForTfLiteTensor(tfLiteInputTensor);
-    armnn::TensorInfo weightsTensorInfo       = GetTensorInfoForTfLiteTensor(tfLiteWeightsTensor);
+    const armnn::TensorInfo& weightsTensorInfo = GetTensorInfoForTfLiteTensor(tfLiteWeightsTensor);
     const armnn::TensorInfo& outputTensorInfo = GetTensorInfoForTfLiteTensor(tfLiteOutputTensor, true);
 
     // Check that we support fused activation before we attempt to create a layer
@@ -82,8 +82,6 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
         return kTfLiteError;
     }
 
-    bool isConstantWeights = tflite::IsConstantTensor(&tfLiteWeightsTensor);
-
     armnn::TensorInfo biasTensorInfo;
     if (biasEnabled)
     {
@@ -141,7 +139,7 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
     armnn::FullyConnectedDescriptor descriptor;
     descriptor.m_TransposeWeightMatrix = true;
     descriptor.m_BiasEnabled           = biasEnabled;
-    descriptor.m_ConstantWeights       = isConstantWeights;
+    descriptor.m_ConstantWeights       = weightsTensorInfo.IsConstant();
 
     bool isSupported = false;
     armnn::BackendId setBackend;
@@ -172,11 +170,10 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
     ARMNN_ASSERT(layer != nullptr);
 
     // Add a constant layer for weights and biases if inputs are constant.
-    if (isConstantWeights)
+    if (weightsTensorInfo.IsConstant())
     {
         auto weightsTensor = CreateConstTensor(&tfLiteWeightsTensor,
-                                               weightsTensorInfo,
-                                               armnn::Optional<armnn::PermutationVector&>());
+                                               weightsTensorInfo);
 
         armnn::IConnectableLayer* weightsLayer = delegateData.m_Network->AddConstantLayer(weightsTensor);
 
@@ -187,11 +184,10 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
     if (biasEnabled)
     {
         const TfLiteTensor& tfLiteBiasTensor = tfLiteTensors[tfLiteNode->inputs->data[2]];
-        if(tflite::IsConstantTensor(&tfLiteBiasTensor))
+        if(biasTensorInfo.IsConstant())
         {
             auto biasTensor = CreateConstTensor(&tfLiteBiasTensor,
-                                                biasTensorInfo,
-                                                armnn::Optional<armnn::PermutationVector&>());
+                                                biasTensorInfo);
 
             armnn::IConnectableLayer* biasLayer = delegateData.m_Network->AddConstantLayer(biasTensor);
             ARMNN_ASSERT(biasLayer != nullptr);
@@ -201,6 +197,18 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
         }
     }
 
+    // The data input can also be constant, so we must check that this is also allocated to an input slot
+    if(inputTensorInfo.IsConstant())
+    {
+        auto input =
+                CreateConstTensor(&tfLiteContext->tensors[tfLiteNode->inputs->data[0]],
+                                  inputTensorInfo);
+
+        armnn::IConnectableLayer *inputLayer = delegateData.m_Network->AddConstantLayer(input);
+        inputLayer->GetOutputSlot(0).Connect(layer->GetInputSlot(0u));
+        inputLayer->GetOutputSlot(0).SetTensorInfo(inputTensorInfo);
+    }
+
     armnn::IOutputSlot& outputSlot = layer->GetOutputSlot(0);
     outputSlot.SetTensorInfo(outputTensorInfo);
 
@@ -224,7 +232,7 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
             delegateData.m_OutputSlotForNode[tfLiteNode->inputs->data[1]]->Connect(layer->GetInputSlot(1));
         }
 
-        if (biasEnabled && !tflite::IsConstantTensor(&tfLiteTensors[tfLiteNode->inputs->data[2]]))
+        if (biasEnabled && !biasTensorInfo.IsConstant())
         {
             delegateData.m_OutputSlotForNode[tfLiteNode->inputs->data[2]]->Connect(layer->GetInputSlot(2));
         }
@@ -233,7 +241,10 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
 
     if (reshapeLayer == nullptr)
     {
-        Connect(layer, tfLiteNode, delegateData);
+        if(Connect(layer, tfLiteNode, delegateData) != kTfLiteOk)
+        {
+            return kTfLiteError;
+        }
     }
     
     if (outputTensorInfo.GetNumDimensions() > 2)