[core] Add CodSpeed C++ benchmarks for protobuf, main loop, and helpers (#14878)

tests/benchmarks/components/main.cpp

@@ -0,0 +1,42 @@
+#include <benchmark/benchmark.h>
+
+#include "esphome/components/logger/logger.h"
+
+/*
+This special main.cpp provides the entry point for Google Benchmark.
+It replaces the default ESPHome main with a benchmark runner.
+
+*/
+
+// Auto generated code by esphome
+// ========== AUTO GENERATED INCLUDE BLOCK BEGIN ===========
+// ========== AUTO GENERATED INCLUDE BLOCK END ===========
+
+void original_setup() {
+  // Code-generated App initialization (pre_setup, area/device registration, etc.)
+
+  // ========== AUTO GENERATED CODE BEGIN ===========
+  // =========== AUTO GENERATED CODE END ============
+}
+
+void setup() {
+  // Run auto-generated initialization (App.pre_setup, area/device registration,
+  // looping_components_.init, etc.) so benchmarks that use App work correctly.
+  original_setup();
+
+  // Log functions call global_logger->log_vprintf_() without a null check,
+  // so we must set up a Logger before any test that triggers logging.
+  static esphome::logger::Logger test_logger(0);
+  test_logger.set_log_level(ESPHOME_LOG_LEVEL);
+  test_logger.pre_setup();
+
+  int argc = 1;
+  char arg0[] = "benchmark";
+  char *argv[] = {arg0, nullptr};
+  ::benchmark::Initialize(&argc, argv);
+  ::benchmark::RunSpecifiedBenchmarks();
+  ::benchmark::Shutdown();
+  exit(0);
+}
+
+void loop() {}