IVGCVSW-6310 Update ICustomAllocator and add GetDefaultAllocator function to backends

Signed-off-by: Francis Murtagh <francis.murtagh@arm.com>
Change-Id: If2879e8a82692285e7fa3f4d09abd608ca28de12

3 files changed, 53 insertions, 0 deletions

diff --git a/src/backends/backendsCommon/DefaultAllocator.hpp b/src/backends/backendsCommon/DefaultAllocator.hpp
new file mode 100644
index 0000000000..2451db3ab8
--- /dev/null
+++ b/src/backends/backendsCommon/DefaultAllocator.hpp
@@ -0,0 +1,45 @@
+//
+// Copyright © 2021 Arm Ltd and Contributors. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#pragma once
+
+#include <cstddef>
+#include <memory>
+#include <armnn/MemorySources.hpp>
+#include <armnn/utility/IgnoreUnused.hpp>
+
+namespace armnn
+{
+
+/** Default Memory Allocator class returned from IBackendInternal::GetDefaultAllocator(MemorySource) */
+class DefaultAllocator : public armnn::ICustomAllocator
+{
+public:
+    DefaultAllocator() = default;
+
+    void* allocate(size_t size, size_t alignment = 0) override
+    {
+        IgnoreUnused(alignment);
+        return ::operator new(size);
+    }
+
+    void free(void* ptr) override
+    {
+        std::free(ptr);
+    }
+
+    armnn::MemorySource GetMemorySourceType() override
+    {
+        return armnn::MemorySource::Malloc;
+    }
+
+    void* GetMemoryRegionAtOffset(void* buffer, size_t offset, size_t alignment = 0) override
+    {
+        IgnoreUnused(alignment);
+        return static_cast<char*>(buffer) + offset;
+    }
+};
+
+} // namespace armnn
\ No newline at end of file
diff --git a/src/backends/backendsCommon/test/MockBackend.cpp b/src/backends/backendsCommon/test/MockBackend.cpp
index df1a5c19aa..4bdb8ce786 100644
--- a/src/backends/backendsCommon/test/MockBackend.cpp
+++ b/src/backends/backendsCommon/test/MockBackend.cpp
@@ -10,6 +10,7 @@
 
 #include <armnn/backends/IBackendContext.hpp>
 #include <armnn/backends/IMemoryManager.hpp>
+#include <backendsCommon/DefaultAllocator.hpp>
 
 #include <Optimizer.hpp>
 #include <SubgraphViewSelector.hpp>
@@ -258,4 +259,9 @@ OptimizationViews MockBackend::OptimizeSubgraphView(const SubgraphView& subgraph
     return optimizationViews;
 }
 
+std::unique_ptr<ICustomAllocator> MockBackend::GetDefaultAllocator() const
+{
+    return std::make_unique<DefaultAllocator>();
+}
+
 } // namespace armnn
diff --git a/src/backends/backendsCommon/test/MockBackend.hpp b/src/backends/backendsCommon/test/MockBackend.hpp
index c0624525dc..6761ce5f08 100644
--- a/src/backends/backendsCommon/test/MockBackend.hpp
+++ b/src/backends/backendsCommon/test/MockBackend.hpp
@@ -165,6 +165,8 @@ public:
     IBackendInternal::ILayerSupportSharedPtr GetLayerSupport() const override;
 
     OptimizationViews OptimizeSubgraphView(const SubgraphView& subgraph) const override;
+
+    std::unique_ptr<ICustomAllocator> GetDefaultAllocator() const override;
 };
 
 class MockLayerSupport : public LayerSupportBase