feat(google_benchmark): add very basic codspeed core library

Author: GuillaumeLagrange

core/CMakeLists.txt

@@ -0,0 +1,21 @@
+cmake_minimum_required(VERSION 3.10)
+project(
+  codspeed
+  VERSION 1.0
+  LANGUAGES CXX)
+
+# Specify the C++ standard
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED True)
+
+# Add the include directory
+include_directories(include)
+
+# Add the library
+add_library(codspeed src/codspeed.cpp)
+
+# Specify the include directories for users of the library
+target_include_directories(
+    codspeed
+    PUBLIC $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
+)

core/include/codspeed.h

@@ -0,0 +1,6 @@
+#ifndef CODSPEED_H
+#define CODSPEED_H
+
+void hello_codspeed();
+
+#endif // CODSPEED_H

core/src/codspeed.cpp

@@ -0,0 +1,6 @@
+#include <codspeed.h>
+#include <iostream>
+
+void hello_codspeed() {
+  std::cout << "Hello from CodSpeed core library!" << std::endl;
+}

google_benchmark/src/CMakeLists.txt

@@ -82,13 +82,18 @@ set_target_properties(benchmark_main PROPERTIES
 )
 target_link_libraries(benchmark_main PUBLIC benchmark::benchmark)
 
+add_subdirectory(${PROJECT_SOURCE_DIR}/../core codspeed)
+
+target_link_libraries(benchmark PRIVATE codspeed)
+
 set(generated_dir "${PROJECT_BINARY_DIR}")
 
 set(version_config "${generated_dir}/${PROJECT_NAME}ConfigVersion.cmake")
 set(project_config "${generated_dir}/${PROJECT_NAME}Config.cmake")
 set(pkg_config "${generated_dir}/${PROJECT_NAME}.pc")
 set(pkg_config_main "${generated_dir}/${PROJECT_NAME}_main.pc")
-set(targets_to_export benchmark benchmark_main)
+# TODO: Find a way to not expose codspeed headers to downstream users
+set(targets_to_export benchmark benchmark_main codspeed)
 set(targets_export_name "${PROJECT_NAME}Targets")
 
 set(namespace "${PROJECT_NAME}::")

google_benchmark/src/benchmark.cc

@@ -16,6 +16,7 @@
 
 #include "benchmark_api_internal.h"
 #include "benchmark_runner.h"
+#include "codspeed.h"
 #include "internal_macros.h"
 
 #ifndef BENCHMARK_OS_WINDOWS
@@ -381,6 +382,8 @@ void RunBenchmarks(const std::vector<BenchmarkInstance>& benchmarks,
   // Note the file_reporter can be null.
   BM_CHECK(display_reporter != nullptr);
 
+  hello_codspeed();
+
   // Determine the width of the name field using a minimum width of 10.
   bool might_have_aggregates = FLAGS_benchmark_repetitions > 1;
   size_t name_field_width = 10;