COMPMID-1710: Avoid undefined behavior in GCC 8.2

Undefined behavior when pushing object which contain unique_ptr to a
vector container. Vector dynamic resizing was making all the unique_ptr
members of the inserted objects up to this point invalid.
As a workaround, memory is reserved to avoid vector reallocation.

Change-Id: I74f7641a7f36981ebe51720a924b865bb7f54c91
Reviewed-on: https://review.mlplatform.org/390
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Pablo Marquez <pablo.tello@arm.com>

2 files changed, 18 insertions, 4 deletions

diff --git a/arm_compute/graph/Workload.h b/arm_compute/graph/Workload.h
index e9368eefd0..682b08d88d 100644
--- a/arm_compute/graph/Workload.h
+++ b/arm_compute/graph/Workload.h
@@ -69,6 +69,20 @@ public:
  */
 struct ExecutionTask
 {
+    ExecutionTask(std::unique_ptr<arm_compute::IFunction> &&f, INode *n)
+        : task(std::move(f)), node(n)
+    {
+    }
+    /** Prevent instances of this class from being copied (As this class contains pointers) */
+    ExecutionTask(const ExecutionTask &) = delete;
+    /** Prevent instances of this class from being copied (As this class contains pointers) */
+    ExecutionTask &operator=(const ExecutionTask &) = delete;
+    /** Default Move Constructor. */
+    ExecutionTask(ExecutionTask &&) noexcept = default;
+    /** Default move assignment operator */
+    ExecutionTask &operator=(ExecutionTask &&) noexcept = default;
+    /** Default destructor */
+    ~ExecutionTask() = default;
     // TODO (geopin01) : Support vector of functions?
     std::unique_ptr<arm_compute::IFunction> task = {}; /**< Task to execute */
     INode                                  *node = {}; /**< Node bound to this workload */
diff --git a/src/graph/detail/ExecutionHelpers.cpp b/src/graph/detail/ExecutionHelpers.cpp
index f2c381b7df..767154b45e 100644
--- a/src/graph/detail/ExecutionHelpers.cpp
+++ b/src/graph/detail/ExecutionHelpers.cpp
@@ -135,6 +135,9 @@ ExecutionWorkload configure_all_nodes(Graph &g, GraphContext &ctx, const std::ve
     workload.graph = &g;
     workload.ctx   = &ctx;
 
+    // Reserve memory for tasks
+    workload.tasks.reserve(node_order.size());
+
     // Create tasks
     for(auto &node_id : node_order)
     {
@@ -146,10 +149,7 @@ ExecutionWorkload configure_all_nodes(Graph &g, GraphContext &ctx, const std::ve
             std::unique_ptr<IFunction> func            = backend.configure_node(*node, ctx);
             if(func != nullptr)
             {
-                ExecutionTask task;
-                task.task = std::move(func);
-                task.node = node;
-                workload.tasks.push_back(std::move(task));
+                workload.tasks.emplace_back(ExecutionTask(std::move(func), node));
             }
         }
     }