Make all CL Concatenate kernels and functions state-less

Resolves COMPMID-3995

Change-Id: I84172bed20924f1d9ae3b4d14d7b321e9494296e
Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4887
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/src/runtime/gpu/cl/operators/ClConcatenate.h b/src/runtime/gpu/cl/operators/ClConcatenate.h
new file mode 100644
index 0000000..112e2ac
--- /dev/null
+++ b/src/runtime/gpu/cl/operators/ClConcatenate.h
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2021 Arm Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef ARM_COMPUTE_CLCONCATENATE_H
+#define ARM_COMPUTE_CLCONCATENATE_H
+
+#include "src/core/gpu/cl/ClCompileContext.h"
+#include "src/core/gpu/cl/IClKernel.h"
+#include "src/runtime/gpu/cl/IClOperator.h"
+
+#include <vector>
+
+namespace arm_compute
+{
+namespace opencl
+{
+/** Basic function to execute concatenate tensors along a given axis. This function calls the following kernels:
+ *
+ * -# @ref kernels::ClWidthConcatenateKernel (if underlying concatenation axis is 0).
+ * -# @ref kernels::ClHeightConcatenateKernel (if underlying concatenation axis is 1).
+ * -# @ref kernels::ClDepthConcatenateKernel (if underlying concatenation axis is 2).
+ * -# @ref kernels::ClBatchConcatenateKernel (if underlying concatenation axis is 3).
+ */
+class ClConcatenate : public IClOperator
+{
+public:
+    /** Default constructor */
+    ClConcatenate();
+    /** Initialise the kernel's inputs vector and dst.
+     *
+     * @note Input and dst tensor dimensions preconditions defer depending on the concatenation axis.
+     * @note Preconditions can be found respectively at @ref kernels::ClWidthConcatenateKernel,
+     *       @ref kernels::ClHeightConcatenateKernel and @ref kernels::ClDepthConcatenateKernel.
+     *
+     *
+     * @param[in]     compile_context The compile context to be used.
+     * @param[in,out] src_vector      The vectors containing all the tensors to concatenate. Data types supported: All
+     * @param[out]    dst             Destination tensor. Data types supported: same as @p src_vector.
+     * @param[in]     axis            Concatenation axis. Supported underlying concatenation axis are 0, 1, 2 and 3.
+     */
+    void configure(const ClCompileContext &compile_context, const std::vector<ITensorInfo *> &src_vector, ITensorInfo *dst, size_t axis);
+    /** Static function to check if given info will lead to a valid configuration of @ref ClConcatenate
+     *
+     * @note Input and dst tensor dimensions preconditions defer depending on the concatenation axis.
+     * @note Preconditions can be found respectively at @ref kernels::ClWidthConcatenateKernel,
+     *       @ref kernels::ClHeightConcatenateKernel and @ref kernels::ClDepthConcatenateKernel.
+     *
+     * @param[in] src_vector The vectors containing all the tensors info to concatenate. Data types supported: All
+     * @param[in] dst        Destination tensor info. Data types supported: same as @p src_vector.
+     * @param[in] axis       Concatenation axis. Supported underlying concatenation axis are 0, 1, 2 and 3.
+     *
+     * @return a status
+     */
+    static Status validate(const std::vector<const ITensorInfo *> &src_vector, const ITensorInfo *dst, size_t axis);
+
+    // Inherited methods overridden:
+    void run(ITensorPack &tensors) override;
+
+private:
+    std::vector<std::unique_ptr<IClKernel>> _concat_kernels;
+    unsigned int                            _num_inputs;
+    unsigned int                            _axis;
+};
+} // namespace opencl
+} // namespace arm_comPUTE
+#endif /* ARM_COMPUTE_CL_CONCATENATE_H */