IVGCVSW-6417: Catch AddFullyConnected API error when weights TensorInfo isn't set

  * Updated code in Graph.cpp InferTensorInfos() to be more descriptive.
  * Added method VerifyConstantLayerSetTensorInfo() in Graph.cpp/hpp
    to error when ConstantLayer TensorInfo is not set.
  * Updated Optimize() in Network.cpp to call VerifyConstantLayerSetTensorInfo().
  * Added unit test with ConstantLayer TensorInfo not
    set to catch error in VerifyConstantLayerSetTensorInfo().
  * Added comments around method VerifyConstantLayerSetTensorInfo().

Signed-off-by: Cathal Corbett <cathal.corbett@arm.com>
Change-Id: I366596243f7c5823676222e2d0cce1335bc8c325

3 files changed, 48 insertions, 6 deletions

diff --git a/src/armnn/Graph.cpp b/src/armnn/Graph.cpp
index 7b6f56f8b8..60bf328c9c 100644
--- a/src/armnn/Graph.cpp
+++ b/src/armnn/Graph.cpp
@@ -526,6 +526,33 @@ void Graph::EraseSubgraphLayers(SubgraphView &subgraph)
     subgraph.Clear();
 }
 
+/// For each ConstantLayer in Graph, ensures TensorInfo is set on all output slots.
+/// LayerValidationException thrown if no TensorInfo is set.
+///
+/// @throws LayerValidationException
+void Graph::VerifyConstantLayerSetTensorInfo() const
+{
+    for (auto&& layer : TopologicalSort())
+    {
+        if(layer->GetType() == armnn::LayerType::Constant)
+        {
+            for (auto&& output: layer->GetOutputSlots())
+            {
+                if (!output.IsTensorInfoSet())
+                {
+                    std::ostringstream message;
+                    message << "Output slot TensorInfo not set on "
+                            << GetLayerTypeAsCString(layer->GetType())
+                            << " layer \""
+                            << layer->GetName()
+                            << "\"";
+                    throw LayerValidationException(message.str());
+                }
+            }
+        }
+    }
+}
+
 void Graph::InferTensorInfos()
 {
     for (auto&& layer : TopologicalSort())
@@ -536,7 +563,9 @@ void Graph::InferTensorInfos()
             if (source == NULL)
             {
                 std::ostringstream message;
-                message << "Input not connected on "
+                message << "Input slot "
+                        << input.GetSlotIndex()
+                        << " not connected to an output slot on "
                         << GetLayerTypeAsCString(layer->GetType())
                         << " layer \""
                         << layer->GetName()
@@ -546,13 +575,19 @@ void Graph::InferTensorInfos()
 
             if (!source->IsTensorInfoSet())
             {
-                throw LayerValidationException("All inputs must have the TensorInfo set at this point.");
+                std::ostringstream message;
+                message << "Output slot TensorInfo not set on "
+                        << GetLayerTypeAsCString(layer->GetType())
+                        << " layer \""
+                        << layer->GetName()
+                        << "\"";
+                throw LayerValidationException(message.str());
             }
+        }
 
-            if (layer->m_ShapeInferenceMethod == ShapeInferenceMethod::ValidateOnly)
-            {
-                layer->ValidateTensorShapesFromInputs();
-            }
+        if (layer->m_ShapeInferenceMethod == ShapeInferenceMethod::ValidateOnly)
+        {
+            layer->ValidateTensorShapesFromInputs();
         }
     }
 }
diff --git a/src/armnn/Graph.hpp b/src/armnn/Graph.hpp
index 731ae1e5aa..d5fbeafed0 100644
--- a/src/armnn/Graph.hpp
+++ b/src/armnn/Graph.hpp
@@ -203,6 +203,10 @@ public:
     void SubstituteSubgraph(SubgraphView& subgraph, IConnectableLayer* substituteLayer);
     void SubstituteSubgraph(SubgraphView& subgraph, const SubgraphView& substituteSubgraph);
 
+    /// For each ConstantLayer in Graph, ensures TensorInfo is set on all output slots.
+    /// LayerValidationException thrown if no TensorInfo is set.
+    void VerifyConstantLayerSetTensorInfo() const;
+
     void InferTensorInfos();
 
     void AttachObservable(IGraphObservable* const observable, GraphEvent notifyOnEvent) {
diff --git a/src/armnn/Network.cpp b/src/armnn/Network.cpp
index a39b6b1a42..39af10f2ac 100644
--- a/src/armnn/Network.cpp
+++ b/src/armnn/Network.cpp
@@ -1576,6 +1576,9 @@ IOptimizedNetworkPtr Optimize(const INetwork& inNetwork,
         throw InvalidArgumentException("BFloat16 and Float16 optimization cannot be enabled at the same time.");
     }
 
+    // Ensure TensorInfo is set on all output slots of ConstantLayers in the graph
+    inNetwork.pNetworkImpl->GetGraph().VerifyConstantLayerSetTensorInfo();
+
     std::unique_ptr<Graph> graph = std::make_unique<Graph>(inNetwork.pNetworkImpl->GetGraph());
 
     auto optNet = IOptimizedNetworkPtr(new IOptimizedNetwork(std::move(graph), options.m_ModelOptions),