Stop using constref signature of benchmark DoNotOptimize. (#2238)

* Stop using constref signature of benchmark DoNotOptimize.

Newer versions of google benchmark (1.8.2 in my case) warn
that the compiler may optimize away the DoNotOptimize calls
when using the constref version.  Get away from that here
by explicitly *not* calling the constref version, casting
where necessary.

Signed-off-by: Chris Lalancette <[email protected]>

Author: clalancette

rclcpp_lifecycle/test/benchmark/benchmark_lifecycle_client.cpp

@@ -228,7 +228,8 @@ class BenchmarkLifecycleClient : public performance_test_fixture::PerformanceTes
 BENCHMARK_F(BenchmarkLifecycleClient, get_state)(benchmark::State & state) {
   for (auto _ : state) {
     (void)_;
-    const auto lifecycle_state = lifecycle_client->get_state();
+
+    lifecycle_msgs::msg::State lifecycle_state = lifecycle_client->get_state();
     if (lifecycle_state.id != lifecycle_msgs::msg::State::PRIMARY_STATE_UNCONFIGURED) {
       const std::string msg =
         std::string("Expected state did not match actual: ") +
@@ -268,7 +269,7 @@ BENCHMARK_F(BenchmarkLifecycleClient, get_available_states)(benchmark::State & s
   for (auto _ : state) {
     (void)_;
     constexpr size_t expected_states = 11u;
-    const auto states = lifecycle_client->get_available_states();
+    std::vector<lifecycle_msgs::msg::State> states = lifecycle_client->get_available_states();
     if (states.size() != expected_states) {
       const std::string msg =
         std::string("Expected number of states did not match actual: ") +
@@ -284,7 +285,8 @@ BENCHMARK_F(BenchmarkLifecycleClient, get_available_transitions)(benchmark::Stat
   for (auto _ : state) {
     (void)_;
     constexpr size_t expected_transitions = 2u;
-    const auto transitions = lifecycle_client->get_available_transitions();
+    std::vector<lifecycle_msgs::msg::TransitionDescription> transitions =
+      lifecycle_client->get_available_transitions();
     if (transitions.size() != expected_transitions) {
       const std::string msg =
         std::string("Expected number of transitions did not match actual: ") +
@@ -300,7 +302,8 @@ BENCHMARK_F(BenchmarkLifecycleClient, get_transition_graph)(benchmark::State & s
   for (auto _ : state) {
     (void)_;
     constexpr size_t expected_transitions = 25u;
-    const auto transitions = lifecycle_client->get_transition_graph();
+    std::vector<lifecycle_msgs::msg::TransitionDescription> transitions =
+      lifecycle_client->get_transition_graph();
     if (transitions.size() != expected_transitions) {
       const std::string msg =
         std::string("Expected number of transitions did not match actual: ") +

rclcpp_lifecycle/test/benchmark/benchmark_lifecycle_node.cpp

@@ -97,13 +97,15 @@ class BenchmarkLifecycleNode : public performance_test_fixture::PerformanceTest
 BENCHMARK_F(BenchmarkLifecycleNode, get_current_state)(benchmark::State & state) {
   for (auto _ : state) {
     (void)_;
-    const auto & lifecycle_state = node->get_current_state();
+    const rclcpp_lifecycle::State & lifecycle_state = node->get_current_state();
     if (lifecycle_state.id() != lifecycle_msgs::msg::State::PRIMARY_STATE_UNCONFIGURED) {
       const std::string message =
         std::string("Node's current state is: ") + std::to_string(lifecycle_state.id());
       state.SkipWithError(message.c_str());
     }
-    benchmark::DoNotOptimize(lifecycle_state);
+    // Google benchmark 1.8.2 warns that the constref DoNotOptimize signature may be optimized away
+    // by the compiler.  Cast const away to ensure we don't get that problem (and warning).
+    benchmark::DoNotOptimize(const_cast<rclcpp_lifecycle::State &>(lifecycle_state));
     benchmark::ClobberMemory();
   }
 }
@@ -112,7 +114,7 @@ BENCHMARK_F(BenchmarkLifecycleNode, get_available_states)(benchmark::State & sta
   for (auto _ : state) {
     (void)_;
     constexpr size_t expected_states = 11u;
-    const auto lifecycle_states = node->get_available_states();
+    std::vector<rclcpp_lifecycle::State> lifecycle_states = node->get_available_states();
     if (lifecycle_states.size() != expected_states) {
       const std::string msg = std::to_string(lifecycle_states.size());
       state.SkipWithError(msg.c_str());
@@ -126,7 +128,7 @@ BENCHMARK_F(BenchmarkLifecycleNode, get_available_transitions)(benchmark::State
   for (auto _ : state) {
     (void)_;
     constexpr size_t expected_transitions = 2u;
-    const auto & transitions = node->get_available_transitions();
+    std::vector<rclcpp_lifecycle::Transition> transitions = node->get_available_transitions();
     if (transitions.size() != expected_transitions) {
       const std::string msg = std::to_string(transitions.size());
       state.SkipWithError(msg.c_str());
@@ -140,7 +142,7 @@ BENCHMARK_F(BenchmarkLifecycleNode, get_transition_graph)(benchmark::State & sta
   for (auto _ : state) {
     (void)_;
     constexpr size_t expected_transitions = 25u;
-    const auto & transitions = node->get_transition_graph();
+    std::vector<rclcpp_lifecycle::Transition> transitions = node->get_transition_graph();
     if (transitions.size() != expected_transitions) {
       const std::string msg =
         std::string("Expected number of transitions did not match actual: ") +
@@ -162,18 +164,20 @@ BENCHMARK_F(BenchmarkLifecycleNode, transition_valid_state)(benchmark::State & s
   reset_heap_counters();
   for (auto _ : state) {
     (void)_;
-    const auto & active =
+    const rclcpp_lifecycle::State & active =
       node->trigger_transition(lifecycle_msgs::msg::Transition::TRANSITION_ACTIVATE);
     if (active.id() != lifecycle_msgs::msg::State::PRIMARY_STATE_ACTIVE) {
       state.SkipWithError("Transition to active state failed");
     }
-    const auto & inactive =
+    const rclcpp_lifecycle::State & inactive =
       node->trigger_transition(lifecycle_msgs::msg::Transition::TRANSITION_DEACTIVATE);
     if (inactive.id() != lifecycle_msgs::msg::State::PRIMARY_STATE_INACTIVE) {
       state.SkipWithError("Transition to inactive state failed");
     }
-    benchmark::DoNotOptimize(active);
-    benchmark::DoNotOptimize(inactive);
+    // Google benchmark 1.8.2 warns that the constref DoNotOptimize signature may be optimized away
+    // by the compiler.  Cast const away to ensure we don't get that problem (and warning).
+    benchmark::DoNotOptimize(const_cast<rclcpp_lifecycle::State &>(active));
+    benchmark::DoNotOptimize(const_cast<rclcpp_lifecycle::State &>(inactive));
     benchmark::ClobberMemory();
   }
 }