Adding Google benchmarking library.

third_party/google_benchmark/CMakeLists.txt

Index: third_party/google_benchmark/CMakeLists.txt
diff --git a/third_party/google_benchmark/CMakeLists.txt b/third_party/google_benchmark/CMakeLists.txt
new file mode 100644
index 0000000000000000000000000000000000000000..f7f1566f5693e878139237971720ce2f64a00fd5
--- /dev/null
+++ b/third_party/google_benchmark/CMakeLists.txt
@@ -0,0 +1,202 @@
+cmake_minimum_required (VERSION 2.8.12)
+
+project (benchmark)
+
+foreach(p
+    CMP0054 # CMake 3.1
+    CMP0056 # export EXE_LINKER_FLAGS to try_run
+    )
+  if(POLICY ${p})
+    cmake_policy(SET ${p} NEW)
+  endif()
+endforeach()
+
+option(BENCHMARK_ENABLE_TESTING "Enable testing of the benchmark library." ON)
+option(BENCHMARK_ENABLE_EXCEPTIONS "Enable the use of exceptions in the benchmark library." ON)
+option(BENCHMARK_ENABLE_LTO "Enable link time optimisation of the benchmark library." OFF)
+option(BENCHMARK_USE_LIBCXX "Build and test using libc++ as the standard library." OFF)
+option(BENCHMARK_BUILD_32_BITS "Build a 32 bit version of the library" OFF)
+
+# Make sure we can import out CMake functions
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+
+# Read the git tags to determine the project version
+include(GetGitVersion)
+get_git_version(GIT_VERSION)
+
+# Tell the user what versions we are using
+string(REGEX MATCH "[0-9]+\\.[0-9]+\\.[0-9]+" VERSION ${GIT_VERSION})
+message("-- Version: ${VERSION}")
+
+# The version of the libraries
+set(GENERIC_LIB_VERSION ${VERSION})
+string(SUBSTRING ${VERSION} 0 1 GENERIC_LIB_SOVERSION)
+
+# Import our CMake modules
+include(CheckCXXCompilerFlag)
+include(AddCXXCompilerFlag)
+include(CXXFeatureCheck)
+
+if (BENCHMARK_BUILD_32_BITS)
+  add_required_cxx_compiler_flag(-m32)
+endif()
+
+if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+  # Turn compiler warnings up to 11
+  string(REGEX REPLACE "[-/]W[1-4]" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
+  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
+
+  if (NOT BENCHMARK_ENABLE_EXCEPTIONS)
+    add_cxx_compiler_flag(-EHs-)
+    add_cxx_compiler_flag(-EHa-)
+  endif()
+  # Link time optimisation
+  if (BENCHMARK_ENABLE_LTO)
+    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /GL")
+    set(CMAKE_STATIC_LINKER_FLAGS_RELEASE "${CMAKE_STATIC_LINKER_FLAGS_RELEASE} /LTCG")
+    set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} /LTCG")
+    set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} /LTCG")
+
+    set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} /GL")
+    string(REGEX REPLACE "[-/]INCREMENTAL" "/INCREMENTAL:NO" CMAKE_STATIC_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_STATIC_LINKER_FLAGS_RELWITHDEBINFO}")
+    set(CMAKE_STATIC_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_STATIC_LINKER_FLAGS_RELWITHDEBINFO} /LTCG")
+    string(REGEX REPLACE "[-/]INCREMENTAL" "/INCREMENTAL:NO" CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO}")
+    set(CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO} /LTCG")
+    string(REGEX REPLACE "[-/]INCREMENTAL" "/INCREMENTAL:NO" CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO}")
+    set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO} /LTCG")
+
+    set(CMAKE_CXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL} /GL")
+    set(CMAKE_STATIC_LINKER_FLAGS_MINSIZEREL "${CMAKE_STATIC_LINKER_FLAGS_MINSIZEREL} /LTCG")
+    set(CMAKE_SHARED_LINKER_FLAGS_MINSIZEREL "${CMAKE_SHARED_LINKER_FLAGS_MINSIZEREL} /LTCG")
+    set(CMAKE_EXE_LINKER_FLAGS_MINSIZEREL "${CMAKE_EXE_LINKER_FLAGS_MINSIZEREL} /LTCG")
+  endif()
+else()
+  # Try and enable C++11. Don't use C++14 because it doesn't work in some
+  # configurations.
+  add_cxx_compiler_flag(-std=c++11)
+  if (NOT HAVE_CXX_FLAG_STD_CXX11)
+    add_cxx_compiler_flag(-std=c++0x)
+  endif()
+
+  # Turn compiler warnings up to 11
+  add_cxx_compiler_flag(-Wall)
+
+  add_cxx_compiler_flag(-Wextra)
+  add_cxx_compiler_flag(-Wshadow)
+  add_cxx_compiler_flag(-Werror RELEASE)
+  add_cxx_compiler_flag(-Werror RELWITHDEBINFO)
+  add_cxx_compiler_flag(-Werror MINSIZEREL)
+  add_cxx_compiler_flag(-pedantic)
+  add_cxx_compiler_flag(-pedantic-errors)
+  add_cxx_compiler_flag(-Wshorten-64-to-32)
+  add_cxx_compiler_flag(-Wfloat-equal)
+  add_cxx_compiler_flag(-fstrict-aliasing)
+  if (NOT BENCHMARK_ENABLE_EXCEPTIONS)
+    add_cxx_compiler_flag(-fno-exceptions)
+  endif()
+  if (NOT BENCHMARK_USE_LIBCXX)
+    add_cxx_compiler_flag(-Wzero-as-null-pointer-constant)
+  endif()
+  if (HAVE_CXX_FLAG_FSTRICT_ALIASING)
+    if (NOT CMAKE_CXX_COMPILER_ID STREQUAL "Intel") #ICC17u2: Many false positives for Wstrict-aliasing
+      add_cxx_compiler_flag(-Wstrict-aliasing)
+    endif()
+  endif()
+  # ICC17u2: overloaded virtual function "benchmark::Fixture::SetUp" is only partially overridden
+  # (because of deprecated overload)
+  add_cxx_compiler_flag(-wd654)  
+  add_cxx_compiler_flag(-Wthread-safety)
+  if (HAVE_CXX_FLAG_WTHREAD_SAFETY)
+    cxx_feature_check(THREAD_SAFETY_ATTRIBUTES)
+  endif()
+
+  # On most UNIX like platforms g++ and clang++ define _GNU_SOURCE as a
+  # predefined macro, which turns on all of the wonderful libc extensions.
+  # However g++ doesn't do this in Cygwin so we have to define it ourselfs
+  # since we depend on GNU/POSIX/BSD extensions.
+  if (CYGWIN)
+    add_definitions(-D_GNU_SOURCE=1)
+  endif()
+
+  # Link time optimisation
+  if (BENCHMARK_ENABLE_LTO)
+    add_cxx_compiler_flag(-flto)
+    if ("${CMAKE_C_COMPILER_ID}" STREQUAL "GNU")
+      find_program(GCC_AR gcc-ar)
+      if (GCC_AR)
+        set(CMAKE_AR ${GCC_AR})
+      endif()
+      find_program(GCC_RANLIB gcc-ranlib)
+      if (GCC_RANLIB)
+        set(CMAKE_RANLIB ${GCC_RANLIB})
+      endif()
+    endif()
+  endif()
+
+  # Coverage build type
+  set(CMAKE_CXX_FLAGS_COVERAGE "${CMAKE_CXX_FLAGS_DEBUG}" CACHE STRING
+    "Flags used by the C++ compiler during coverage builds."
+    FORCE)
+  set(CMAKE_EXE_LINKER_FLAGS_COVERAGE
+    "${CMAKE_EXE_LINKER_FLAGS_DEBUG}" CACHE STRING
+    "Flags used for linking binaries during coverage builds."
+    FORCE)
+  set(CMAKE_SHARED_LINKER_FLAGS_COVERAGE
+    "${CMAKE_SHARED_LINKER_FLAGS_DEBUG}" CACHE STRING
+    "Flags used by the shared libraries linker during coverage builds."
+    FORCE)
+  mark_as_advanced(
+    CMAKE_CXX_FLAGS_COVERAGE
+    CMAKE_EXE_LINKER_FLAGS_COVERAGE
+    CMAKE_SHARED_LINKER_FLAGS_COVERAGE)
+  set(CMAKE_BUILD_TYPE "${CMAKE_BUILD_TYPE}" CACHE STRING
+    "Choose the type of build, options are: None Debug Release RelWithDebInfo MinSizeRel Coverage."
+    FORCE)
+  add_cxx_compiler_flag(--coverage COVERAGE)
+endif()
+
+if (BENCHMARK_USE_LIBCXX)
+  if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+    add_cxx_compiler_flag(-stdlib=libc++)
+  elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" OR
+          "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Intel")
+    add_cxx_compiler_flag(-nostdinc++)
+    message("libc++ header path must be manually specified using CMAKE_CXX_FLAGS")
+    # Adding -nodefaultlibs directly to CMAKE_<TYPE>_LINKER_FLAGS will break
+    # configuration checks such as 'find_package(Threads)'
+    list(APPEND BENCHMARK_CXX_LINKER_FLAGS -nodefaultlibs)
+    # -lc++ cannot be added directly to CMAKE_<TYPE>_LINKER_FLAGS because
+    # linker flags appear before all linker inputs and -lc++ must appear after.
+    list(APPEND BENCHMARK_CXX_LIBRARIES c++)
+  else()
+    message(FATAL "-DBENCHMARK_USE_LIBCXX:BOOL=ON is not supported for compiler")
+  endif()
+endif(BENCHMARK_USE_LIBCXX)
+
+# C++ feature checks
+# Determine the correct regular expression engine to use
+cxx_feature_check(STD_REGEX)
+cxx_feature_check(GNU_POSIX_REGEX)
+cxx_feature_check(POSIX_REGEX)
+if(NOT HAVE_STD_REGEX AND NOT HAVE_GNU_POSIX_REGEX AND NOT HAVE_POSIX_REGEX)
+  message(FATAL_ERROR "Failed to determine the source files for the regular expression backend")
+endif()
+if (NOT BENCHMARK_ENABLE_EXCEPTIONS AND HAVE_STD_REGEX
+        AND NOT HAVE_GNU_POSIX_REGEX AND NOT HAVE_POSIX_REGEX)
+  message(WARNING "Using std::regex with exceptions disabled is not fully supported")
+endif()
+cxx_feature_check(STEADY_CLOCK)
+# Ensure we have pthreads
+find_package(Threads REQUIRED)
+
+# Set up directories
+include_directories(${PROJECT_SOURCE_DIR}/include)
+
+# Build the targets
+add_subdirectory(src)
+
+if (BENCHMARK_ENABLE_TESTING)
+  enable_testing()
+  add_subdirectory(test)
+endif()