Update google benchmark version / adopt benchmarks to changes

Author: oshadura

cmake/modules/GoogleBenchmark.cmake

@@ -9,7 +9,7 @@ set(GBENCHMARK_LIBRARY_NAME ${CMAKE_STATIC_LIBRARY_PREFIX}benchmark${CMAKE_STATI
 ExternalProject_Add(
   googlebenchmark
   GIT_REPOSITORY https://github.com/google/benchmark.git
-  GIT_TAG v1.5.5
+  GIT_TAG v1.6.0
   UPDATE_COMMAND ""
   # TIMEOUT 10
   # # Force separate output paths for debug and release builds to allow easy
@@ -44,4 +44,4 @@ set(_GBENCH_LIBRARY_PATH ${binary_dir}/)
 # Register googlebenchmark
 add_library(gbenchmark IMPORTED STATIC GLOBAL)
 set_property(TARGET gbenchmark PROPERTY IMPORTED_LOCATION ${_GBENCH_LIBRARY_PATH}/src/libbenchmark.a)
-add_dependencies(gbenchmark googlebenchmark)
+add_dependencies(gbenchmark googlebenchmark)

root/io/io/TBufferMergerBenchmarks.cxx

@@ -32,7 +32,7 @@ TBufferMerger *Merger = nullptr;
 static void BM_TBufferFile_GetFile(benchmark::State &state)
 {
    ROOT::EnableThreadSafety();
-   if (state.thread_index == 0) {
+   if (state.thread_index() == 0) {
       // Setup code here.
       // FIXME: We should have a way to pass an externally constructed file or stream to
       // TFile*, this would allow us to create in-memory files and avoid killing disks
@@ -43,7 +43,7 @@ static void BM_TBufferFile_GetFile(benchmark::State &state)
       // Run the test as normal.
       auto myFile = Merger->GetFile();
    }
-   if (state.thread_index == 0) {
+   if (state.thread_index() == 0) {
       // Teardown code here.
       delete Merger;
    }
@@ -87,7 +87,7 @@ inline void FillTreeWithRandomData(TBufferMerger &merger, size_t nEntriesPerWork
 static void BM_TBufferFile_FillTreeWithRandomData(benchmark::State &state)
 {
    ROOT::EnableThreadSafety();
-   if (state.thread_index == 0) {
+   if (state.thread_index() == 0) {
       // Setup code here.
       Merger = new TBufferMerger(std::unique_ptr<TMemFile>(new TMemFile("virtual_file.root", "RECREATE")));
    }
@@ -100,7 +100,7 @@ static void BM_TBufferFile_FillTreeWithRandomData(benchmark::State &state)
    std::stringstream ss;
    ss << size;
    state.SetLabel(ss.str());
-   if (state.thread_index == 0) {
+   if (state.thread_index() == 0) {
       // Teardown code here.
       delete Merger;
    }