Change TileOperand to a view of a tile object

* TileOperand instead of being the tile object now is only a view
  of a tile object.
  - declare_tile now returns a TileOperand object, not a reference
    to a TileOperand object.
  - This is to prepare for the posibility that the users need
    to perform operations on part of a tile (e.g. a scalar value,
    a vector, a sub-tile).

Partially resolves: COMPMID-6391
Signed-off-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Change-Id: I35c08b22a384a756d99dcd04cbe66fc57bd548d2
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/9958
Reviewed-by: Gunes Bayir <gunes.bayir@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>

2 files changed, 33 insertions, 15 deletions

diff --git a/compute_kernel_writer/include/ckw/KernelWriter.h b/compute_kernel_writer/include/ckw/KernelWriter.h
index 85ae47f686..cfd24d35a3 100644
--- a/compute_kernel_writer/include/ckw/KernelWriter.h
+++ b/compute_kernel_writer/include/ckw/KernelWriter.h
@@ -28,7 +28,6 @@
 #include "ckw/TileOperand.h"
 
 #include <memory>
-#include <set>
 #include <string>
 
 namespace ckw
@@ -103,23 +102,30 @@ public:
      *
      * @returns The created tile operand
      */
-    virtual TileOperand &declare_tile(const std::string &name, const TileInfo &tile_info) = 0;
+    virtual TileOperand declare_tile(const std::string &name, const TileInfo &tile_info) = 0;
 
 protected:
     int32_t id_space() const;
 
-    /** Pure virtual function to be overridden by language specific subclasses to add a tile operand to the kernel */
-    virtual TileOperand &add_operand(const std::string &name, const TileInfo &tile_info) = 0;
-
-    /** Add a tile operand to the operand list */
-    TileOperand &add_operand(std::unique_ptr<TileOperand> &operand_ptr);
-
     /** Generate full variable name by prefixing it with id space */
     std::string generate_full_name(const std::string &name) const;
 
+    /** Create a new tile operand referring to the specified tile object.
+     *
+     * This class has friendship relationship with @ref TileOperand which allows it
+     * to access the private constructor.
+     */
+    static TileOperand create_tile_operand(ITile &tile);
+
+    /** Get the reference to tile object from the tile operand.
+     *
+     * This class has friendship relationship with @ref TileOperand which allows it
+     * to access the private reference to the private tile field.
+     */
+    static ITile &get_tile(const TileOperand &operand);
+
 private:
     int32_t _id_space{ 0 };
-    std::set<std::unique_ptr<TileOperand>> _operands {};
 };
 
 } // namespace ckw
diff --git a/compute_kernel_writer/include/ckw/TileOperand.h b/compute_kernel_writer/include/ckw/TileOperand.h
index abd3e0ac97..fe44b73e82 100644
--- a/compute_kernel_writer/include/ckw/TileOperand.h
+++ b/compute_kernel_writer/include/ckw/TileOperand.h
@@ -22,20 +22,32 @@
  * SOFTWARE.
  */
 
-#ifndef CKW_INCLUDE_CKW_TILEOPERAND
-#define CKW_INCLUDE_CKW_TILEOPERAND
+#ifndef CKW_INCLUDE_CKW_TILEOPERAND_H
+#define CKW_INCLUDE_CKW_TILEOPERAND_H
 
 namespace ckw
 {
 
-/** Tile operand which can be either scalar, vector or 2D tile. */
+class KernelWriter;
+class ITile;
+
+/** A tile operand refers to a tile object that can be used for kernel writing. */
 class TileOperand
 {
 public:
-    /* Destructor */
-    virtual ~TileOperand();
+    // The constructor and _tile field is completely hidden from the public API to avoid any misuse.
+    // Only kernel writer class interacts with tile operand hence we allow it to access this field.
+    friend class KernelWriter;
+
+private:
+    // These are hidden from the public API to avoid any misuse.
+
+    /** Initialize a new instance of @ref TileOperand class for the given tile. */
+    TileOperand(ITile &tile);
+
+    ITile &_tile;
 };
 
 } // namespace ckw
 
-#endif /* COMPUTE_KERNEL_WRITER_INCLUDE_CKW_TILEOPERAND */
+#endif // CKW_INCLUDE_CKW_TILEOPERAND_H