Ensure we don't need benchmark installed to pass c++ feature checks (#1456)

* Ensure we don't need benchmark installed to pass c++ feature checks

Requires removal of some dependencies on benchmark.h from internal
low-level headers, which is a good thing.

Also added better logging to the feature check cmake module.

CMakeLists.txt

@@ -223,7 +223,7 @@ else()
   add_cxx_compiler_flag(-wd654)
   add_cxx_compiler_flag(-Wthread-safety)
   if (HAVE_CXX_FLAG_WTHREAD_SAFETY)
-    cxx_feature_check(THREAD_SAFETY_ATTRIBUTES)
+    cxx_feature_check(THREAD_SAFETY_ATTRIBUTES "-DINCLUDE_DIRECTORIES=${PROJECT_SOURCE_DIR}/include")
   endif()
 
   # On most UNIX like platforms g++ and clang++ define _GNU_SOURCE as a

cmake/CXXFeatureCheck.cmake

@@ -27,17 +27,18 @@ function(cxx_feature_check FILE)
     return()
   endif()
 
+  set(FEATURE_CHECK_CMAKE_FLAGS ${BENCHMARK_CXX_LINKER_FLAGS})
   if (ARGC GREATER 1)
     message(STATUS "Enabling additional flags: ${ARGV1}")
-    list(APPEND BENCHMARK_CXX_LINKER_FLAGS ${ARGV1})
+    list(APPEND FEATURE_CHECK_CMAKE_FLAGS ${ARGV1})
   endif()
 
   if (NOT DEFINED COMPILE_${FEATURE})
-    message(STATUS "Performing Test ${FEATURE}")
     if(CMAKE_CROSSCOMPILING)
+      message(STATUS "Cross-compiling to test ${FEATURE}")
       try_compile(COMPILE_${FEATURE}
               ${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/cmake/${FILE}.cpp
-              CMAKE_FLAGS ${BENCHMARK_CXX_LINKER_FLAGS}
+              CMAKE_FLAGS ${FEATURE_CHECK_CMAKE_FLAGS}
               LINK_LIBRARIES ${BENCHMARK_CXX_LIBRARIES}
               OUTPUT_VARIABLE COMPILE_OUTPUT_VAR)
       if(COMPILE_${FEATURE})
@@ -48,10 +49,10 @@ function(cxx_feature_check FILE)
         set(RUN_${FEATURE} 1 CACHE INTERNAL "")
       endif()
     else()
-      message(STATUS "Performing Test ${FEATURE}")
+      message(STATUS "Compiling and running to test ${FEATURE}")
       try_run(RUN_${FEATURE} COMPILE_${FEATURE}
               ${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/cmake/${FILE}.cpp
-              CMAKE_FLAGS ${BENCHMARK_CXX_LINKER_FLAGS}
+              CMAKE_FLAGS ${FEATURE_CHECK_CMAKE_FLAGS}
               LINK_LIBRARIES ${BENCHMARK_CXX_LIBRARIES}
               COMPILE_OUTPUT_VARIABLE COMPILE_OUTPUT_VAR)
     endif()

include/benchmark/benchmark.h

@@ -220,22 +220,11 @@ BENCHMARK(BM_test)->Unit(benchmark::kMillisecond);
 
 #if defined(__GNUC__) || defined(__clang__)
 #define BENCHMARK_ALWAYS_INLINE __attribute__((always_inline))
-#define BENCHMARK_NOEXCEPT noexcept
-#define BENCHMARK_NOEXCEPT_OP(x) noexcept(x)
 #elif defined(_MSC_VER) && !defined(__clang__)
 #define BENCHMARK_ALWAYS_INLINE __forceinline
-#if _MSC_VER >= 1900
-#define BENCHMARK_NOEXCEPT noexcept
-#define BENCHMARK_NOEXCEPT_OP(x) noexcept(x)
-#else
-#define BENCHMARK_NOEXCEPT
-#define BENCHMARK_NOEXCEPT_OP(x)
-#endif
 #define __func__ __FUNCTION__
 #else
 #define BENCHMARK_ALWAYS_INLINE
-#define BENCHMARK_NOEXCEPT
-#define BENCHMARK_NOEXCEPT_OP(x)
 #endif
 
 #define BENCHMARK_INTERNAL_TOSTRING2(x) #x

src/benchmark_register.h

@@ -1,6 +1,7 @@
 #ifndef BENCHMARK_REGISTER_H
 #define BENCHMARK_REGISTER_H
 
+#include <algorithm>
 #include <limits>
 #include <vector>
 

src/check.h

@@ -9,6 +9,23 @@
 #include "internal_macros.h"
 #include "log.h"
 
+#if defined(__GNUC__) || defined(__clang__)
+#define BENCHMARK_NOEXCEPT noexcept
+#define BENCHMARK_NOEXCEPT_OP(x) noexcept(x)
+#elif defined(_MSC_VER) && !defined(__clang__)
+#if _MSC_VER >= 1900
+#define BENCHMARK_NOEXCEPT noexcept
+#define BENCHMARK_NOEXCEPT_OP(x) noexcept(x)
+#else
+#define BENCHMARK_NOEXCEPT
+#define BENCHMARK_NOEXCEPT_OP(x)
+#endif
+#define __func__ __FUNCTION__
+#else
+#define BENCHMARK_NOEXCEPT
+#define BENCHMARK_NOEXCEPT_OP(x)
+#endif
+
 namespace benchmark {
 namespace internal {
 

src/internal_macros.h

@@ -1,8 +1,6 @@
 #ifndef BENCHMARK_INTERNAL_MACROS_H_
 #define BENCHMARK_INTERNAL_MACROS_H_
 
-#include "benchmark/benchmark.h"
-
 /* Needed to detect STL */
 #include <cstdlib>
 

src/log.h

@@ -4,7 +4,12 @@
 #include <iostream>
 #include <ostream>
 
-#include "benchmark/benchmark.h"
+// NOTE: this is also defined in benchmark.h but we're trying to avoid a
+// dependency.
+// The _MSVC_LANG check should detect Visual Studio 2015 Update 3 and newer.
+#if __cplusplus >= 201103L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201103L)
+#define BENCHMARK_HAS_CXX11
+#endif
 
 namespace benchmark {
 namespace internal {
@@ -23,7 +28,16 @@ class LogType {
  private:
   LogType(std::ostream* out) : out_(out) {}
   std::ostream* out_;
-  BENCHMARK_DISALLOW_COPY_AND_ASSIGN(LogType);
+
+  // NOTE: we could use BENCHMARK_DISALLOW_COPY_AND_ASSIGN but we shouldn't have
+  // a dependency on benchmark.h from here.
+#ifndef BENCHMARK_HAS_CXX11
+  LogType(const LogType&);
+  LogType& operator=(const LogType&);
+#else
+  LogType(const LogType&) = delete;
+  LogType& operator=(const LogType&) = delete;
+#endif
 };
 
 template <class Tp>
@@ -47,13 +61,13 @@ inline int& LogLevel() {
 }
 
 inline LogType& GetNullLogInstance() {
-  static LogType log(nullptr);
-  return log;
+  static LogType null_log((std::ostream*)nullptr);
+  return null_log;
 }
 
 inline LogType& GetErrorLogInstance() {
-  static LogType log(&std::clog);
-  return log;
+  static LogType error_log(&std::clog);
+  return error_log;
 }
 
 inline LogType& GetLogInstanceForLevel(int level) {

src/string_util.h

@@ -4,8 +4,10 @@
 #include <sstream>
 #include <string>
 #include <utility>
+#include <vector>
 
 #include "benchmark/export.h"
+#include "check.h"
 #include "internal_macros.h"
 
 namespace benchmark {

test/benchmark_gtest.cc

@@ -3,6 +3,7 @@
 #include <vector>
 
 #include "../src/benchmark_register.h"
+#include "benchmark/benchmark.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 
@@ -135,8 +136,7 @@ TEST(AddRangeTest, Simple8) {
 }
 
 TEST(AddCustomContext, Simple) {
-  std::map<std::string, std::string> *&global_context =
-      internal::GetGlobalContext();
+  std::map<std::string, std::string> *&global_context = GetGlobalContext();
   EXPECT_THAT(global_context, nullptr);
 
   AddCustomContext("foo", "bar");
@@ -151,8 +151,7 @@ TEST(AddCustomContext, Simple) {
 }
 
 TEST(AddCustomContext, DuplicateKey) {
-  std::map<std::string, std::string> *&global_context =
-      internal::GetGlobalContext();
+  std::map<std::string, std::string> *&global_context = GetGlobalContext();
   EXPECT_THAT(global_context, nullptr);
 
   AddCustomContext("foo", "bar");