Address RVO issue on some compilers

Suppresses pessimizing-move during clang compilation as for some gcc
toolchains RVO is not ensured until C++17 thus an explicit call to
std::move might be required to avoid compilation error for non-copyable
ojects (e.g. std::unique_ptr)

Resolves: COMPMID-3599

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: Ie3fa44fb0cf631655aecbeb6c82021a68f500a33
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4230
Reviewed-by: Giorgio Arena <giorgio.arena@arm.com>
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>

5 files changed, 59 insertions, 61 deletions

diff --git a/SConscript b/SConscript
index 656336d555..2b70ca18b8 100644
--- a/SConscript
+++ b/SConscript
@@ -42,14 +42,14 @@ def build_bootcode_objs(sources):
     Default(obj)
     return obj
 
-def build_library(name, sources, static=False, libs=[]):
+def build_library(name, build_env, sources, static=False, libs=[]):
     if static:
-        obj = arm_compute_env.StaticLibrary(name, source=sources, LIBS = arm_compute_env["LIBS"] + libs)
+        obj = build_env.StaticLibrary(name, source=sources, LIBS = arm_compute_env["LIBS"] + libs)
     else:
         if env['set_soname']:
-            obj = arm_compute_env.SharedLibrary(name, source=sources, SHLIBVERSION = SONAME_VERSION, LIBS = arm_compute_env["LIBS"] + libs)
+            obj = build_env.SharedLibrary(name, source=sources, SHLIBVERSION = SONAME_VERSION, LIBS = arm_compute_env["LIBS"] + libs)
         else:
-            obj = arm_compute_env.SharedLibrary(name, source=sources, LIBS = arm_compute_env["LIBS"] + libs)
+            obj = build_env.SharedLibrary(name, source=sources, LIBS = arm_compute_env["LIBS"] + libs)
 
     obj = install_lib(obj)
     Default(obj)
@@ -137,6 +137,9 @@ arm_compute_env = env.Clone()
 version_file = arm_compute_env.Command("src/core/arm_compute_version.embed", "", action=create_version_file)
 arm_compute_env.AlwaysBuild(version_file)
 
+default_cpp_compiler = 'g++' if env['os'] != 'android' else 'clang++'
+cpp_compiler = os.environ.get('CXX', default_cpp_compiler)
+
 # Generate embed files
 generate_embed = [ version_file ]
 if env['opencl'] and env['embed_kernels']:
@@ -282,26 +285,29 @@ if env['os'] == 'bare_metal':
     bootcode_o = build_bootcode_objs(bootcode_files)
 Export('bootcode_o')
 
-arm_compute_core_a = build_library('arm_compute_core-static', core_files, static=True)
+arm_compute_core_a = build_library('arm_compute_core-static', arm_compute_env, core_files, static=True)
 Export('arm_compute_core_a')
 
 if env['os'] != 'bare_metal' and not env['standalone']:
-    arm_compute_core_so = build_library('arm_compute_core', core_files, static=False)
+    arm_compute_core_so = build_library('arm_compute_core', arm_compute_env, core_files, static=False)
     Export('arm_compute_core_so')
 
-arm_compute_a = build_library('arm_compute-static', runtime_files, static=True, libs = [ arm_compute_core_a ])
+arm_compute_a = build_library('arm_compute-static', arm_compute_env, runtime_files, static=True, libs = [ arm_compute_core_a ])
 Export('arm_compute_a')
 
 if env['os'] != 'bare_metal' and not env['standalone']:
-    arm_compute_so = build_library('arm_compute', runtime_files, static=False, libs = [ "arm_compute_core" ])
+    arm_compute_so = build_library('arm_compute', arm_compute_env, runtime_files, static=False, libs = [ "arm_compute_core" ])
     Depends(arm_compute_so, arm_compute_core_so)
     Export('arm_compute_so')
 
-arm_compute_graph_a = build_library('arm_compute_graph-static', graph_files, static=True, libs = [ arm_compute_a])
+arm_compute_graph_env = arm_compute_env.Clone();
+if 'clang++' in cpp_compiler:
+    arm_compute_graph_env.Append(CXXFLAGS = ['-Wno-pessimizing-move'])
+arm_compute_graph_a = build_library('arm_compute_graph-static', arm_compute_graph_env, graph_files, static=True, libs = [ arm_compute_a])
 Export('arm_compute_graph_a')
 
 if env['os'] != 'bare_metal' and not env['standalone']:
-    arm_compute_graph_so = build_library('arm_compute_graph', graph_files, static=False, libs = [ "arm_compute" , "arm_compute_core"])
+    arm_compute_graph_so = build_library('arm_compute_graph', arm_compute_graph_env, graph_files, static=False, libs = [ "arm_compute" , "arm_compute_core"])
     Depends(arm_compute_graph_so, arm_compute_so)
     Export('arm_compute_graph_so')
 
diff --git a/arm_compute/graph/backends/FunctionHelpers.h b/arm_compute/graph/backends/FunctionHelpers.h
index 873957e6b7..ee5dc3e285 100644
--- a/arm_compute/graph/backends/FunctionHelpers.h
+++ b/arm_compute/graph/backends/FunctionHelpers.h
@@ -47,13 +47,6 @@ namespace backends
 {
 namespace detail
 {
-// Address rule DR-9R5 (1579. Return by converting move constructor)
-#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 5))
-#define RETURN_UNIQUE_PTR(x) (x)
-#else /* defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 5)) */
-#define RETURN_UNIQUE_PTR(x) (std::move(x))
-#endif /* defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 5)) */
-
 /** Returns backing tensor of a given tensor
  *
  * @tparam TargetInfo Target information
@@ -128,7 +121,7 @@ std::unique_ptr<IFunction> create_activation_layer(ActivationLayerNode &node)
                                << " InPlace : " << is_in_place_operation(input, output)
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Creates a backend argminmax layer function
@@ -165,7 +158,7 @@ std::unique_ptr<IFunction> create_arg_min_max_layer(ArgMinMaxLayerNode &node)
                                << " axis: " << axis
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend batch normalization layer function
@@ -209,7 +202,7 @@ std::unique_ptr<IFunction> create_batch_normalization_layer(BatchNormalizationLa
                                << " InPlace: " << is_in_place_operation(input, output)
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend batch normalization layer function
@@ -266,7 +259,7 @@ std::unique_ptr<IFunction> create_fused_convolution_batch_normalization_layer(Fu
                                << " Output shape: " << output->info()->tensor_shape()
                                << (fused_act.enabled() ? " " + to_string(fused_act.activation()) : "")
                                << std::endl);
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend fused depthwise convolution batch normalization layer function
@@ -322,7 +315,7 @@ std::unique_ptr<IFunction> create_fused_depthwise_convolution_batch_normalizatio
                                << " Output shape: " << output->info()->tensor_shape()
                                << (fused_act.enabled() ? " " + to_string(fused_act.activation()) : "")
                                << std::endl);
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend bounding box transform layer function
@@ -360,7 +353,7 @@ std::unique_ptr<IFunction> create_bounding_box_transform_layer(BoundingBoxTransf
                                << " BoundingBox Info img H: " << bbox_info.img_height() << " "
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend channel shuffle layer function
@@ -395,7 +388,7 @@ std::unique_ptr<IFunction> create_channel_shuffle_layer(ChannelShuffleLayerNode
                                << " Num groups: " << num_groups
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend layer concatenate function
@@ -451,7 +444,7 @@ std::unique_ptr<arm_compute::IFunction> create_concatenate_layer(ConcatenateLaye
                                << qss.str()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend convolution layer function
@@ -542,7 +535,7 @@ std::unique_ptr<IFunction> create_convolution_layer(ConvolutionLayerNode &node,
                                << qss.str()
                                << (fused_act.enabled() ? " " + to_string(fused_act.activation()) : "")
                                << std::endl);
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend deconvolution layer function
@@ -648,7 +641,7 @@ std::unique_ptr<IFunction> create_depthwise_convolution_layer(DepthwiseConvoluti
                                << qss.str()
                                << (fused_act.enabled() ? " " + to_string(fused_act.activation()) : "")
                                << std::endl);
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend depth to space layer function
@@ -687,7 +680,7 @@ std::unique_ptr<IFunction> create_depth_to_space_layer(DepthToSpaceLayerNode &no
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend dequantize layer function
@@ -726,7 +719,7 @@ std::unique_ptr<IFunction> create_dequantization_layer(DequantizationLayerNode &
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 /** Create a backend detection output layer function
  *
@@ -771,7 +764,7 @@ std::unique_ptr<IFunction> create_detection_output_layer(DetectionOutputLayerNod
                                << " DetectionOutputLayer info: " << detect_info
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend detection post process layer function
@@ -826,7 +819,7 @@ std::unique_ptr<IFunction> create_detection_post_process_layer(DetectionPostProc
                                << " DetectionPostProcessLayer info: " << detect_info
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend element-wise operation layer function
@@ -895,7 +888,7 @@ std::unique_ptr<IFunction> create_eltwise_layer(EltwiseLayerNode &node)
                                << " Shape: " << input1->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend unary element-wise operation layer function
@@ -943,7 +936,7 @@ std::unique_ptr<IFunction> create_unary_eltwise_layer(UnaryEltwiseLayerNode &nod
                                << " Shape: " << input->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend flatten layer function
@@ -981,7 +974,7 @@ std::unique_ptr<IFunction> create_flatten_layer(FlattenLayerNode &node)
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend fully connected layer function
@@ -1037,7 +1030,7 @@ std::unique_ptr<IFunction> create_fully_connected_layer(FullyConnectedLayerNode
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend generate proposals layer function
@@ -1086,7 +1079,7 @@ std::unique_ptr<IFunction> create_generate_proposals_layer(GenerateProposalsLaye
                                << " Scores Out shape: " << scores_out->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend l2 normalization layer function
@@ -1130,7 +1123,7 @@ std::unique_ptr<IFunction> create_l2_normalize_layer(L2NormalizeLayerNode &node,
                                << " Epsilon: " << epsilon
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend normalization layer function
@@ -1172,7 +1165,7 @@ std::unique_ptr<IFunction> create_normalization_layer(NormalizationLayerNode &no
                                << " Normalization info: " << norm_info.type()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend normalize planar YUV layer function
@@ -1212,7 +1205,7 @@ std::unique_ptr<IFunction> create_normalize_planar_yuv_layer(NormalizePlanarYUVL
                                << " Shape: " << input->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend pad layer function
@@ -1251,7 +1244,7 @@ std::unique_ptr<IFunction> create_pad_layer(PadLayerNode &node)
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend permute layer function
@@ -1290,7 +1283,7 @@ std::unique_ptr<IFunction> create_permute_layer(PermuteLayerNode &node)
                                << " Permutation vector: " << perm
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend pooling layer function
@@ -1329,7 +1322,7 @@ std::unique_ptr<IFunction> create_pooling_layer(PoolingLayerNode &node)
                                << " Pooling info: " << pool_info.pool_type
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend PRelu layer function
@@ -1367,7 +1360,7 @@ std::unique_ptr<IFunction> create_prelu_layer(PReluLayerNode &node)
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend print layer function
@@ -1438,7 +1431,7 @@ std::unique_ptr<IFunction> create_priorbox_layer(PriorBoxLayerNode &node)
                                << " PriorBoxLayer info: " << prior_info
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend quantization layer function
@@ -1475,7 +1468,7 @@ std::unique_ptr<IFunction> create_quantization_layer(QuantizationLayerNode &node
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend reduction operation layer function
@@ -1519,7 +1512,7 @@ std::unique_ptr<IFunction> create_reduction_operation_layer(ReductionLayerNode &
                                << " Keep dimensions:" << keep_dims
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend reorg layer function
@@ -1556,7 +1549,7 @@ std::unique_ptr<IFunction> create_reorg_layer(ReorgLayerNode &node)
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend reshape layer function
@@ -1593,7 +1586,7 @@ std::unique_ptr<IFunction> create_reshape_layer(ReshapeLayerNode &node)
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend resize layer function
@@ -1632,7 +1625,7 @@ std::unique_ptr<IFunction> create_resize_layer(ResizeLayerNode &node)
                                << " Interpolation: " << policy
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend ROI align layer function
@@ -1677,7 +1670,7 @@ std::unique_ptr<IFunction> create_roi_align_layer(ROIAlignLayerNode &node)
                                << " ROIPooling height: " << pool_info.pooled_height()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend slice layer function
@@ -1714,7 +1707,7 @@ std::unique_ptr<IFunction> create_slice_layer(SliceLayerNode &node)
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend softmax layer function
@@ -1753,7 +1746,7 @@ std::unique_ptr<IFunction> create_softmax_layer(SoftmaxLayerNode &node, GraphCon
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend layer stack function
@@ -1796,7 +1789,7 @@ std::unique_ptr<arm_compute::IFunction> create_stack_layer(StackLayerNode &node)
                                << " Axis: " << axis
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 
 /** Create a backend slice layer function
@@ -1838,7 +1831,7 @@ std::unique_ptr<IFunction> create_strided_slice_layer(StridedSliceLayerNode &nod
                                << " Output shape: " << output->info()->tensor_shape()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 } // namespace detail
 } // namespace backends
diff --git a/src/graph/backends/CL/CLFunctionsFactory.cpp b/src/graph/backends/CL/CLFunctionsFactory.cpp
index 619641804b..5c98ce3b85 100644
--- a/src/graph/backends/CL/CLFunctionsFactory.cpp
+++ b/src/graph/backends/CL/CLFunctionsFactory.cpp
@@ -167,7 +167,7 @@ std::unique_ptr<IFunction> create_detection_output_layer<CPPDetectionOutputLayer
     wrap_function->register_tensor(input2);
     wrap_function->register_tensor(output);
 
-    return RETURN_UNIQUE_PTR(wrap_function);
+    return std::move(wrap_function);
 }
 template <>
 std::unique_ptr<IFunction> create_detection_post_process_layer<CPPDetectionPostProcessLayer, CLTargetInfo>(DetectionPostProcessLayerNode &node)
@@ -223,7 +223,7 @@ std::unique_ptr<IFunction> create_detection_post_process_layer<CPPDetectionPostP
     wrap_function->register_tensor(output2);
     wrap_function->register_tensor(output3);
 
-    return RETURN_UNIQUE_PTR(wrap_function);
+    return std::move(wrap_function);
 }
 } // namespace detail
 
diff --git a/src/graph/backends/GLES/GCFunctionsFactory.cpp b/src/graph/backends/GLES/GCFunctionsFactory.cpp
index 7d9d388ebe..ac14425ad4 100644
--- a/src/graph/backends/GLES/GCFunctionsFactory.cpp
+++ b/src/graph/backends/GLES/GCFunctionsFactory.cpp
@@ -120,7 +120,7 @@ std::unique_ptr<IFunction> create_convolution_layer<GCConvolutionLayerFunctions,
                                << " Output shape: " << output->info()->tensor_shape()
                                << (fused_act.enabled() ? " " + to_string(fused_act.activation()) : "")
                                << std::endl);
-    return func;
+    return std::move(func);
 }
 
 template <>
@@ -172,7 +172,7 @@ std::unique_ptr<IFunction> create_depthwise_convolution_layer<GCDepthwiseConvolu
                                << " Depth multiplier: " << depth_multiplier
                                << (fused_act.enabled() ? " " + to_string(fused_act.activation()) : "")
                                << std::endl);
-    return func;
+    return std::move(func);
 }
 
 template <>
@@ -226,7 +226,7 @@ std::unique_ptr<IFunction> create_eltwise_layer<GCEltwiseFunctions, GCTargetInfo
                                << " Shape: " << input1->info()->tensor_shape()
                                << std::endl);
 
-    return func;
+    return std::move(func);
 }
 } //namespace detail
 
diff --git a/src/graph/backends/NEON/NEFunctionFactory.cpp b/src/graph/backends/NEON/NEFunctionFactory.cpp
index b2bd87070c..6a96f0a5b9 100644
--- a/src/graph/backends/NEON/NEFunctionFactory.cpp
+++ b/src/graph/backends/NEON/NEFunctionFactory.cpp
@@ -32,7 +32,6 @@
 #include "arm_compute/graph/nodes/Nodes.h"
 #include "arm_compute/runtime/CPP/CPPFunctions.h"
 #include "arm_compute/runtime/NEON/NEFunctions.h"
-#include "src/core/NEON/NEKernels.h"
 #include "support/Cast.h"
 #include "support/ToolchainSupport.h"
 
@@ -116,7 +115,7 @@ std::unique_ptr<IFunction> create_normalization_layer<NENormalizationLayer, NETa
                                << " Normalization info: " << norm_info.type()
                                << std::endl);
 
-    return RETURN_UNIQUE_PTR(func);
+    return std::move(func);
 }
 } // namespace detail