IVGCVSW-6298 'IMemoryOptimizerStrategy Add declarations and constant layer strategy'

* Added IMemoryOptimizerStrategy interface
* Added ConstLayerMemoryOptimizer strategy

Signed-off-by: Sadik Armagan <sadik.armagan@arm.com>
Change-Id: I6a92e659379e5cc39c375b669678eee8a8c08c20

3 files changed, 71 insertions, 0 deletions

diff --git a/include/armnn/Types.hpp b/include/armnn/Types.hpp
index 19e93c3c7e..0b7b941008 100644
--- a/include/armnn/Types.hpp
+++ b/include/armnn/Types.hpp
@@ -213,6 +213,19 @@ enum class MemorySource : uint32_t
     DmaBufProtected = 4
 };
 
+enum class MemBlockStrategyType
+{
+    // MemBlocks can be packed on the Y axis only.
+    // In other words MemBlocks with overlapping lifetimes cannot use the same MemBin,
+    // equivalent to blob or pooling memory management.
+    SingleAxisPacking  = 0,
+
+    // MemBlocks can be packed on the Y and X axis.
+    // In other words MemBlocks with overlapping lifetimes can use the same MemBin,
+    // equivalent to offset or slab memory management.
+    MultiAxisPacking  = 1
+};
+
 /// Each backend should implement an IBackend.
 class IBackend
 {
diff --git a/include/armnn/backends/CMakeLists.txt b/include/armnn/backends/CMakeLists.txt
index 58d0abf872..19046ed977 100644
--- a/include/armnn/backends/CMakeLists.txt
+++ b/include/armnn/backends/CMakeLists.txt
@@ -10,6 +10,7 @@ list(APPEND armnnBackendsAPI_sources
      IBackendInternal.hpp
      IBackendContext.hpp
      IMemoryManager.hpp
+     IMemoryOptimizerStrategy.hpp
      ITensorHandle.hpp
      ITensorHandleFactory.hpp
      IWorkload.hpp
diff --git a/include/armnn/backends/IMemoryOptimizerStrategy.hpp b/include/armnn/backends/IMemoryOptimizerStrategy.hpp
new file mode 100644
index 0000000000..ec6d838aae
--- /dev/null
+++ b/include/armnn/backends/IMemoryOptimizerStrategy.hpp
@@ -0,0 +1,57 @@
+//
+// Copyright © 2021 Arm Ltd and Contributors. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+#pragma once
+
+#include <armnn/Types.hpp>
+
+namespace armnn
+{
+
+// A MemBlock represents a memory usage requirement in time and space and can be seen as essentially a rectangle
+struct MemBlock
+{
+    MemBlock(const unsigned int startOfLife,
+             const unsigned int endOfLife,
+             const size_t memSize,
+             size_t offset,
+             const unsigned int index)
+    : m_StartOfLife(startOfLife), m_EndOfLife(endOfLife), m_MemSize(memSize), m_Offset(offset), m_Index(index) {}
+
+    const unsigned int m_StartOfLife; // Y start
+    const unsigned int m_EndOfLife; // Y end
+
+    const size_t m_MemSize; // X start
+    size_t m_Offset; // X end
+
+    const unsigned int m_Index; // Index to keep order
+};
+
+// A MemBin represents a single contiguous area of memory that can store 1-n number of MemBlocks
+struct MemBin
+{
+    std::vector<MemBlock> m_MemBlocks;
+    size_t m_MemSize;
+};
+
+// IMemoryOptimizerStrategy will set m_Offset of the MemBlocks,
+// sort them into 1-n bins, then pair each bin of MemBlocks with an int specifying it's total size
+// A IMemoryOptimizerStrategy must ensure that
+// 1: All MemBlocks have been assigned to a MemBin
+// 2: No MemBlock is assigned to multiple MemBins
+// 3: No two MemBlocks in a MemBin overlap in the X dimension
+//    (a strategy cannot change the y axis or length of a MemBlock)
+class IMemoryOptimizerStrategy
+{
+public:
+    virtual ~IMemoryOptimizerStrategy() {}
+
+    virtual std::string GetName() const = 0;
+
+    virtual MemBlockStrategyType GetMemBlockStrategyType() const = 0;
+
+    virtual std::vector<MemBin> Optimize(std::vector<MemBlock>& memBlocks) = 0;
+};
+
+} // namespace armnn
\ No newline at end of file