IVGCVSW-4212 Example of standalone dynamic reference backend

 * Add example to build dynamic reference backend
 * Add functions to clear dynamic backends
 * Fix the error when dynamic backend is not deregistered
 * Add DYARMNN_DYNAMIC_BACKEND_ENABLED to check disable empty
   dynamic backend when dynamic backend is enabled

Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: I1ef3a3f10ed6ca5ec18d0af04b007fc3bc71a3cb

3 files changed, 83 insertions, 0 deletions

diff --git a/src/dynamic/reference/CMakeLists.txt b/src/dynamic/reference/CMakeLists.txt
new file mode 100644
index 0000000000..79bf7ec362
--- /dev/null
+++ b/src/dynamic/reference/CMakeLists.txt
@@ -0,0 +1,35 @@
+#
+# Copyright © 2019 Arm Ltd. All rights reserved.
+# SPDX-License-Identifier: MIT
+#
+
+cmake_minimum_required (VERSION 3.0.2)
+
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
+# File needed to wrap the existing backend into a dynamic one
+list(APPEND armnnRefDynamicBackend_sources
+    RefDynamicBackend.cpp
+    RefDynamicBackend.hpp
+)
+
+# Set the backend source path
+set(RefBackendPath ${PROJECT_SOURCE_DIR}/../../../src/backends/reference)
+
+# Source files of the backend, taken directly from the source tree
+file(GLOB RefBackendBaseFiles ${RefBackendPath}/*.cpp)
+file(GLOB RefBackendWorloadFiles ${RefBackendPath}/workloads/*.cpp)
+set(RefBackendFiles ${RefBackendBaseFiles} ${RefBackendWorloadFiles})
+
+# Remove the file that contains the static backend registration
+list(REMOVE_ITEM RefBackendFiles ${RefBackendPath}/RefRegistryInitializer.cpp)
+
+# Create the shared object
+add_library(Arm_CpuRef_backend MODULE ${armnnRefDynamicBackend_sources} ${RefBackendFiles})
+
+target_include_directories(Arm_CpuRef_backend PRIVATE ${PROJECT_SOURCE_DIR}/../../../include)
+target_include_directories(Arm_CpuRef_backend PRIVATE ${PROJECT_SOURCE_DIR}/../../../third-party) # for half
+target_include_directories(Arm_CpuRef_backend PRIVATE ${PROJECT_SOURCE_DIR}/../../../src/armnn)
+target_include_directories(Arm_CpuRef_backend PRIVATE ${PROJECT_SOURCE_DIR}/../../../src/armnnUtils)
+target_include_directories(Arm_CpuRef_backend PRIVATE ${PROJECT_SOURCE_DIR}/../../../src/backends)
+target_include_directories(Arm_CpuRef_backend PRIVATE ${PROJECT_SOURCE_DIR}/../../../src/profiling)
\ No newline at end of file
diff --git a/src/dynamic/reference/RefDynamicBackend.cpp b/src/dynamic/reference/RefDynamicBackend.cpp
new file mode 100644
index 0000000000..f2ed0f6033
--- /dev/null
+++ b/src/dynamic/reference/RefDynamicBackend.cpp
@@ -0,0 +1,33 @@
+//
+// Copyright © 2019 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#include "RefDynamicBackend.hpp"
+
+#include <reference/RefBackend.hpp>
+
+using namespace armnn;
+
+const char* GetBackendId()
+{
+    return RefBackend::GetIdStatic().Get().c_str();
+}
+
+void GetVersion(uint32_t* outMajor, uint32_t* outMinor)
+{
+    if (!outMajor || !outMinor)
+    {
+        return;
+    }
+
+    BackendVersion apiVersion = IBackendInternal::GetApiVersion();
+
+    *outMajor = apiVersion.m_Major;
+    *outMinor = apiVersion.m_Minor;
+}
+
+void* BackendFactory()
+{
+    return new RefBackend();
+}
diff --git a/src/dynamic/reference/RefDynamicBackend.hpp b/src/dynamic/reference/RefDynamicBackend.hpp
new file mode 100644
index 0000000000..bc680a1fba
--- /dev/null
+++ b/src/dynamic/reference/RefDynamicBackend.hpp
@@ -0,0 +1,15 @@
+//
+// Copyright © 2019 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#pragma once
+
+#include <cstdint>
+
+extern "C"
+{
+const char* GetBackendId();
+void GetVersion(uint32_t* outMajor, uint32_t* outMinor);
+void* BackendFactory();
+}