IVGCVSW-6382 Add Gather operator support to ONNX parser

 * Add ParseGather to support Gather operator on ONNX
 * Add Support of int64 converted to int32 for constant
 * Add OnnxParserTestUtils
 * Refactor ValidateTensorShapesFromInputs of GatherLayer
 * Unit tests

Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: Ie9dff640240e14a062fef38f7faf0ccc212de5f7

2 files changed, 29 insertions, 14 deletions

diff --git a/src/armnn/layers/GatherLayer.cpp b/src/armnn/layers/GatherLayer.cpp
index 9a4f9bf8f0..cdbdaabcdc 100644
--- a/src/armnn/layers/GatherLayer.cpp
+++ b/src/armnn/layers/GatherLayer.cpp
@@ -31,16 +31,11 @@ GatherLayer* GatherLayer::Clone(Graph& graph) const
     return CloneBase<GatherLayer>(graph, m_Param, GetName());
 }
 
-void GatherLayer::ValidateTensorShapesFromInputs()
+std::vector<TensorShape> GatherLayer::InferOutputShapes(const std::vector<TensorShape>& inputShapes) const
 {
-    VerifyLayerConnections(2, CHECK_LOCATION());
-
-    const TensorShape& outputShape = GetOutputSlot(0).GetTensorInfo().GetShape();
-
-    VerifyShapeInferenceType(outputShape, m_ShapeInferenceMethod);
-
-    const TensorInfo& params = GetInputSlot(0).GetConnection()->GetTensorInfo();
-    const TensorInfo& indices = GetInputSlot(1).GetConnection()->GetTensorInfo();
+    ARMNN_ASSERT(inputShapes.size() == 2);
+    const TensorShape& params = inputShapes[0];
+    const TensorShape& indices = inputShapes[1];
 
     const unsigned int paramsDim = params.GetNumDimensions();
     const unsigned int indicesDim = indices.GetNumDimensions();
@@ -57,20 +52,35 @@ void GatherLayer::ValidateTensorShapesFromInputs()
 
     for (unsigned int i = 0; i < axis; ++i)
     {
-        dimSizes.push_back(params.GetShape()[i]);
+        dimSizes.push_back(params[i]);
     }
     for (unsigned int i = axis; i < indicesDim + axis; ++i)
     {
-        dimSizes.push_back(indices.GetShape()[i - axis]);
+        dimSizes.push_back(indices[i - axis]);
     }
     for (unsigned int i = 1 + axis; i < paramsDim; ++i)
     {
-        dimSizes.push_back(params.GetShape()[i]);
+        dimSizes.push_back(params[i]);
     }
 
-    const TensorShape& inferredShape = TensorShape(outputDim, dimSizes.data());
+    return std::vector<TensorShape>({ TensorShape({outputDim, dimSizes.data()})});
+}
+
+void GatherLayer::ValidateTensorShapesFromInputs()
+{
+    VerifyLayerConnections(2, CHECK_LOCATION());
+
+    const TensorShape& outputShape = GetOutputSlot(0).GetTensorInfo().GetShape();
+
+    VerifyShapeInferenceType(outputShape, m_ShapeInferenceMethod);
+
+    std::vector<TensorShape> inferredShapes = InferOutputShapes(
+            {GetInputSlot(0).GetConnection()->GetTensorInfo().GetShape(),
+             GetInputSlot(1).GetConnection()->GetTensorInfo().GetShape()});
+    ARMNN_ASSERT(inferredShapes.size() == 1);
+    ARMNN_ASSERT(inferredShapes[0].GetDimensionality() == Dimensionality::Specified);
 
-    ValidateAndCopyShape(outputShape, inferredShape, m_ShapeInferenceMethod, "GatherLayer");
+    ValidateAndCopyShape(outputShape, inferredShapes[0], m_ShapeInferenceMethod, "GatherLayer");
 }
 
 void GatherLayer::Accept(ILayerVisitor& visitor) const
diff --git a/src/armnn/layers/GatherLayer.hpp b/src/armnn/layers/GatherLayer.hpp
index 010af37b49..3bc8c69bc4 100644
--- a/src/armnn/layers/GatherLayer.hpp
+++ b/src/armnn/layers/GatherLayer.hpp
@@ -24,6 +24,11 @@ public:
     /// @param [in] graph The graph into which this layer is being cloned.
     GatherLayer* Clone(Graph& graph) const override;
 
+    /// Infers the output shapes from given input shapes and layer properties.
+    /// @param [in] inputShapes The input shapes layer has.
+    /// @return A vector to the inferred output shape.
+    std::vector<TensorShape> InferOutputShapes(const std::vector<TensorShape>& inputShapes) const override;
+
     /// Check if the input tensor shape(s).
     /// will lead to a valid configuration of @ref GatherLayer.
     /// @param [in] shapeInferenceMethod Indicates if output shape shall be overwritten or just validate.