Fix use-after-free in `TensorViewLayout::get_shape()` (#174)

* isolate graph building / execution scope in some unit tests (this triggered the user-after-free which was also observed from TF)

* Change descriptor::layout::TensorViewLayout to store a shared pointer to the TensorViewType rather than a reference to the TensorView

src/ngraph/descriptor/layout/tensor_view_layout.hpp

@@ -35,7 +35,7 @@ namespace ngraph
             {
             protected:
                 TensorViewLayout(const ngraph::descriptor::TensorView& tensor_view)
-                    : m_tensor_view(tensor_view)
+                    : m_tensor_view_type(tensor_view.get_tensor_view_type())
                 {
                 }
 
@@ -53,19 +53,14 @@ namespace ngraph
 
                 const element::Type& get_element_type() const
                 {
-                    return m_tensor_view.get_tensor_view_type()->get_element_type();
+                    return m_tensor_view_type->get_element_type();
                 }
-
-                const Shape& get_shape() const
-                {
-                    return m_tensor_view.get_tensor_view_type()->get_shape();
-                }
-
+                const Shape& get_shape() const { return m_tensor_view_type->get_shape(); }
                 /// Where this view is located in the buffer.
                 const BufferPos& get_buffer_pos() const { return m_buffer_pos; }
                 BufferPos& get_buffer_pos() { return m_buffer_pos; }
             protected:
-                const ngraph::descriptor::TensorView& m_tensor_view;
+                std::shared_ptr<const TensorViewType> m_tensor_view_type;
                 BufferPos m_buffer_pos;
             };
         }

test/execute.cpp

@@ -341,14 +341,19 @@ TEST(execute, test_concat_vector)
 
 TEST(execute, test_divide)
 {
-    auto shape = Shape{2, 2};
-    auto A = make_shared<op::Parameter>(element::Float32::element_type(), shape);
-    auto B = make_shared<op::Parameter>(element::Float32::element_type(), shape);
-    auto rt = make_shared<TensorViewType>(element::Float32::element_type(), shape);
-    auto f = make_shared<Function>(make_shared<op::Divide>(A, B), rt, op::Parameters{A, B});
+    auto make_external = []() {
+        auto shape = Shape{2, 2};
+        auto A = make_shared<op::Parameter>(element::Float32::element_type(), shape);
+        auto B = make_shared<op::Parameter>(element::Float32::element_type(), shape);
+        auto rt = make_shared<TensorViewType>(element::Float32::element_type(), shape);
+        auto f = make_shared<Function>(make_shared<op::Divide>(A, B), rt, op::Parameters{A, B});
 
-    auto external = make_shared<ngraph::runtime::ExternalFunction>(f);
-    auto cf = external->make_call_frame();
+        auto external = make_shared<ngraph::runtime::ExternalFunction>(f);
+        return external;
+    };
+
+    auto shape = Shape{2, 2};
+    auto cf = make_external()->make_call_frame();
 
     // Create some tensors for input/output
     auto a = ngraph::runtime::make_tensor<element::Float32>(shape);
@@ -408,16 +413,23 @@ TEST(execute, test_dot_0_0)
 
 TEST(execute, test_dot_matrix_2x0_0x2)
 {
+    auto make_external = []() {
+        auto shape_a = Shape{2, 0};
+        auto A = make_shared<op::Parameter>(element::Float32::element_type(), shape_a);
+        auto shape_b = Shape{0, 2};
+        auto B = make_shared<op::Parameter>(element::Float32::element_type(), shape_b);
+        auto shape_r = Shape{2, 2};
+        auto rt = make_shared<TensorViewType>(element::Float32::element_type(), shape_r);
+        auto f = make_shared<Function>(make_shared<op::Dot>(A, B), rt, op::Parameters{A, B});
+
+        auto external = make_shared<ngraph::runtime::ExternalFunction>(f);
+        return external;
+    };
+
     auto shape_a = Shape{2, 0};
-    auto A = make_shared<op::Parameter>(element::Float32::element_type(), shape_a);
     auto shape_b = Shape{0, 2};
-    auto B = make_shared<op::Parameter>(element::Float32::element_type(), shape_b);
     auto shape_r = Shape{2, 2};
-    auto rt = make_shared<TensorViewType>(element::Float32::element_type(), shape_r);
-    auto f = make_shared<Function>(make_shared<op::Dot>(A, B), rt, op::Parameters{A, B});
-
-    auto external = make_shared<ngraph::runtime::ExternalFunction>(f);
-    auto cf = external->make_call_frame();
+    auto cf = make_external()->make_call_frame();
 
     // Create some tensors for input/output
     auto a = ngraph::runtime::make_tensor<element::Float32>(shape_a);