Compute kernel writer API and prototype

* Add the public API for compute kernel writer.
* Use the prototype as the implementation of the public API.

Resolves: COMPMID-5790
Signed-off-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Change-Id: I9d80e15325e1d953feb87c1f2eb61a587bb9ab5e
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/9814
Reviewed-by: Jakub Sujak <jakub.sujak@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
diff --git a/compute_kernel_writer/examples/add_exp_store.cpp b/compute_kernel_writer/examples/add_exp_store.cpp
new file mode 100644
index 0000000..ab2f3e1
--- /dev/null
+++ b/compute_kernel_writer/examples/add_exp_store.cpp
@@ -0,0 +1,181 @@
+/*
+ * Copyright (c) 2023 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.
+ */
+
+#include "ckw/Error.h"
+#include "ckw/KernelWriter.h"
+#include "ckw/TensorOperand.h"
+#include "ckw/TensorTileSampler.h"
+#include "ckw/TileOperand.h"
+#include "ckw/Types.h"
+
+#include "acl/AclComponentArgument.h"
+#include "acl/AclKernelWriter.h"
+#include "acl/AclScopedKernelWriter.h"
+
+#include <iostream>
+#include <vector>
+
+using namespace ckw;
+
+TensorTileSampler create_simple_sampler(AclScopedKernelWriter writer)
+{
+    TensorTileSampler sampler;
+
+    constexpr int32_t m0 = 4;
+    constexpr int32_t n0 = 4;
+
+    auto &gid_0 = writer->declare_tile("gid_0", DataType::Int32);
+    auto &gid_1 = writer->declare_tile("gid_1", DataType::Int32);
+    auto &gid_2 = writer->declare_tile("gid_2", DataType::Int32);
+
+    auto &const_0 = writer->declare_tile("0", 0);
+
+    writer->op_get_global_id(gid_0, 0);
+    writer->op_get_global_id(gid_1, 1);
+    writer->op_get_global_id(gid_2, 2);
+
+    sampler.x(gid_0);
+    sampler.y(gid_1);
+    sampler.z(gid_2);
+    sampler.b(const_0);
+
+    sampler.width(n0);
+    sampler.height(m0);
+
+    sampler.format(TensorSamplerFormat::C_WH_1);
+    sampler.address_mode_x(TensorSamplerAddressModeX::None);
+    sampler.address_mode_y(TensorSamplerAddressModeY::ClampToBorder);
+    sampler.address_mode_z(TensorSamplerAddressModeZ::Skip);
+
+    return sampler;
+}
+
+void op_binary_elementwise(AclScopedKernelWriter writer, std::vector<AclComponentArgument *> operands)
+{
+    auto lhs = operands.at(0);
+    auto rhs = operands.at(1);
+    auto dst = operands.at(2);
+
+    // Load the LHS and RHS tile and prepare the tensor sampler.
+    if(!lhs->has_tile() && !rhs->has_tile())
+    {
+        const auto sampler = create_simple_sampler(writer);
+
+        writer->op_load_once(lhs, sampler);
+        writer->op_load_once(rhs, sampler);
+    }
+    else if(lhs->has_tile())
+    {
+        const auto &sampler = lhs->tile_sampler();
+        writer->op_load_once(rhs, sampler);
+    }
+    else
+    {
+        const auto &sampler = rhs->tile_sampler();
+        writer->op_load_once(lhs, sampler);
+    }
+
+    auto       &lhs_tile = lhs->tile();
+    auto       &rhs_tile = rhs->tile();
+    const auto &sampler  = lhs->tile_sampler();
+
+    // Prepare the output tile.
+    if(!dst->has_tile())
+    {
+        auto &tile = writer->declare_tile("dst_tile", lhs_tile.tile_info());
+        dst->init_virtual_tensor(tile, sampler);
+    }
+
+    auto &dst_tile = dst->tile();
+
+    // Perform the operation.
+    writer->op_binary_expression(dst_tile, lhs_tile, rhs_tile, BinaryOp::Add);
+}
+
+void op_exp(AclScopedKernelWriter writer, std::vector<AclComponentArgument *> operands)
+{
+    auto src = operands.at(0);
+    auto dst = operands.at(1);
+
+    // Load the source tile and prepare the sampler.
+    if(!src->has_tile())
+    {
+        const auto sampler = create_simple_sampler(writer);
+        writer->op_load_once(src, sampler);
+    }
+
+    auto       &src_tile = src->tile();
+    const auto &sampler  = src->tile_sampler();
+
+    // Prepare the output tile.
+    if(!dst->has_tile())
+    {
+        auto &tile = writer->declare_tile("dst_tile", src_tile.tile_info());
+        dst->init_virtual_tensor(tile, sampler);
+    }
+
+    auto &dst_tile = dst->tile();
+
+    // Perform the operation.
+    writer->op_scalar_function(dst_tile, src_tile, ScalarUnaryFunction::Exp);
+}
+
+void op_store(AclScopedKernelWriter writer, std::vector<AclComponentArgument *> operands)
+{
+    auto src = operands.at(0);
+    auto dst = operands.at(1);
+
+    auto       &src_tile   = src->tile();
+    const auto &sampler    = src->tile_sampler();
+    auto       &dst_tensor = dst->tensor();
+
+    writer->op_store(dst_tensor, src_tile, sampler);
+}
+
+int main()
+{
+    Kernel          kernel("example", GpuTargetLanguage::OpenCL);
+    AclKernelWriter root_writer(kernel);
+
+    AclScopedKernelWriter writer(&root_writer);
+
+    const TensorInfo src0_info(DataType::Fp32, TensorShape({ 3, 10, 20, 1, 1 }), TensorDataLayout::Nhwc, 0);
+    const TensorInfo src1_info(DataType::Fp32, TensorShape({ 3, 10, 20, 1, 1 }), TensorDataLayout::Nhwc, 1);
+    const TensorInfo dst_info(DataType::Fp32, TensorShape({ 3, 10, 20, 1, 1 }), TensorDataLayout::Nhwc, 2);
+
+    AclComponentArgument src0(writer->create_tensor_argument("src0", src0_info));
+    AclComponentArgument src1(writer->create_tensor_argument("src1", src1_info));
+    AclComponentArgument dst(writer->create_tensor_argument("dst", dst_info));
+
+    AclComponentArgument ans;
+
+    op_binary_elementwise(writer, { &src0, &src1, &ans });
+    op_exp(writer, { &ans, &ans });
+    op_store(writer, { &ans, &dst });
+
+    const auto code = root_writer.generate_code();
+    std::cout << code;
+
+    return 0;
+}