[libc++][ranges] Add benchmarks for the `from_range` constructors of `vector` and `deque`.

[var-const]

Try to set the language version via set_target_properties instead of target_compile_options in case it works around the CMake issue on Windows.

[Mordante]

I would prefer to have the CMake changes in a separate patch. I'm happy with these changes after applying my suggestion.

libcxx/benchmarks/CMakeLists.txt

1–5

It seems I missed this hunk when I updated the CMake requirements. This version is now validated by the top-level script.

[var-const]

Rebase

[var-const]

Fix the CI

[var-const]

Fix CI

[var-const]

Rerun the Windows CI

[var-const]

Rebase.

[var-const]

Experiment to fix the CI

[Mordante]

LGTM after adding a comment.

libcxx/benchmarks/CMakeLists.txt

85

Please add a bit of comment here, once MSVC has cxx_std_23 support we should use that instead.

[var-const]

Address feedback

[var-const]

Address feedback

[sivachandra]

libcxx/benchmarks/CMakeLists.txt

92

This line seems to have taken down the runtimes sphinx docs builder: https://lab.llvm.org/buildbot/#/builders/242/builds/950

The builder seems to be using an old version of gcc which doesn't know about cxx_std_23. Could we perhaps skip benchmarks if we are using an old compiler?

[var-const]

libcxx/benchmarks/CMakeLists.txt

92

Hopefully https://github.com/llvm/llvm-zorg/pull/47 will fix that.

[sivachandra]

libcxx/benchmarks/CMakeLists.txt

92

Thanks. It needs a buildbot restart to take effect, which hopefully will happen soon enough.

libcxx/benchmarks/CMakeLists.txt

-if (CMAKE_VERSION VERSION_LESS 3.17)
+if (CMAKE_VERSION VERSION_LESS 3.20)
   message(WARNING "The libc++ benchmarks won't be available because the version of CMake is too old to support them.")
   return()
 endif()
 
 include(ExternalProject)
 include(CheckCXXCompilerFlag)
 
 #==============================================================================
 # Build Google Benchmark for libc++
 #==============================================================================
 
 set(CMAKE_FOLDER "${CMAKE_FOLDER}/Benchmarks")

 # Benchmark tests configuration
 #==============================================================================
 add_custom_target(cxx-benchmarks)
 set(BENCHMARK_OUTPUT_DIR ${CMAKE_CURRENT_BINARY_DIR})
 set(BENCHMARK_LIBCXX_INSTALL ${CMAKE_CURRENT_BINARY_DIR}/benchmark-libcxx)
 set(BENCHMARK_NATIVE_INSTALL ${CMAKE_CURRENT_BINARY_DIR}/benchmark-native)
 
 add_library(               cxx-benchmarks-flags INTERFACE)
-target_compile_features(   cxx-benchmarks-flags INTERFACE cxx_std_20)
+
 target_compile_options(    cxx-benchmarks-flags INTERFACE -fsized-deallocation -nostdinc++)
 target_include_directories(cxx-benchmarks-flags INTERFACE "${LIBCXX_GENERATED_INCLUDE_DIR}"
                                                 INTERFACE "${BENCHMARK_LIBCXX_INSTALL}/include"
                                                 INTERFACE "${LIBCXX_SOURCE_DIR}/test/support")
 
 add_library(           cxx-benchmarks-flags-native INTERFACE)
 target_link_libraries( cxx-benchmarks-flags-native INTERFACE cxx-benchmarks-flags)
 target_compile_options(cxx-benchmarks-flags-native INTERFACE ${BENCHMARK_NATIVE_TARGET_FLAGS})
 target_link_options(   cxx-benchmarks-flags-native INTERFACE ${BENCHMARK_NATIVE_TARGET_FLAGS} "-L${BENCHMARK_NATIVE_INSTALL}/lib")
 if (LIBCXX_BENCHMARK_NATIVE_STDLIB STREQUAL "libstdc++")
   find_library(LIBSTDCXX_FILESYSTEM_TEST stdc++fs
         PATHS ${LIBCXX_BENCHMARK_NATIVE_GCC_TOOLCHAIN}
         PATH_SUFFIXES lib lib64
         DOC "The libstdc++ filesystem library used by the benchmarks"
     )
   if (LIBSTDCXX_FILESYSTEM_TEST)
function(add_benchmark_test name source_file)
   target_link_libraries(${libcxx_target} PRIVATE cxx_experimental benchmark)
   if (LLVM_USE_SANITIZER)
     target_link_libraries(${libcxx_target} PRIVATE -ldl)
   endif()
   set_target_properties(${libcxx_target}
     PROPERTIES
           OUTPUT_NAME "${name}.libcxx.out"
           RUNTIME_OUTPUT_DIRECTORY "${BENCHMARK_OUTPUT_DIR}"
+          CXX_STANDARD 23
+          CXX_STANDARD_REQUIRED YES
           CXX_EXTENSIONS NO)
+
   cxx_link_system_libraries(${libcxx_target})
   if (LIBCXX_BENCHMARK_NATIVE_STDLIB)
     set(native_target ${name}_native)
     add_executable(${native_target} EXCLUDE_FROM_ALL ${source_file})
     target_link_libraries(${native_target} PRIVATE cxx-benchmarks-flags-native)
     add_dependencies(${native_target} google-benchmark-native
                                       google-benchmark-libcxx)
     target_link_libraries(${native_target} PRIVATE -lbenchmark)
     if (LIBCXX_HAS_PTHREAD_LIB)
       target_link_libraries(${native_target} PRIVATE -pthread)
     endif()
     add_dependencies(cxx-benchmarks ${native_target})
     set_target_properties(${native_target}
       PROPERTIES
           OUTPUT_NAME "${name}.native.out"
           RUNTIME_OUTPUT_DIRECTORY "${BENCHMARK_OUTPUT_DIR}"
+          CXX_STANDARD 23
+          CXX_STANDARD_REQUIRED YES
           CXX_EXTENSIONS NO)
   endif()
 endfunction()
 
 
 #==============================================================================
 # Register Benchmark tests
 #==============================================================================

libcxx/benchmarks/ContainerBenchmarks.h

void BM_ConstructIterIter(benchmark::State& st, Container, GenInputs gen) {
     benchmark::DoNotOptimize(&in);
     while (st.KeepRunning()) {
         Container c(begin, end);
         DoNotOptimizeData(c);
     }
 }
 
 template <class Container, class GenInputs>
+void BM_ConstructFromRange(benchmark::State& st, Container, GenInputs gen) {
+    auto in = gen(st.range(0));
+    benchmark::DoNotOptimize(&in);
+    while (st.KeepRunning()) {
+        Container c(std::from_range, in);
+        DoNotOptimizeData(c);
+    }
+}
+
+template <class Container, class GenInputs>
 void BM_InsertValue(benchmark::State& st, Container c, GenInputs gen) {
     auto in = gen(st.range(0));
     const auto end = in.end();
     while (st.KeepRunning()) {
         c.clear();
         for (auto it = in.begin(); it != end; ++it) {
             benchmark::DoNotOptimize(&(*c.insert(*it).first));
         }

libcxx/benchmarks/deque.bench.cpp

BENCHMARK_CAPTURE(BM_ConstructIterIter,
   std::deque<size_t>{},
   getRandomIntegerInputs<size_t>)->Arg(TestNumInputs);
 
 BENCHMARK_CAPTURE(BM_ConstructIterIter,
   deque_string,
   std::deque<std::string>{},
   getRandomStringInputs)->Arg(TestNumInputs);
 
+BENCHMARK_CAPTURE(BM_ConstructFromRange,
+  deque_char,
+  std::deque<char>{},
+  getRandomIntegerInputs<char>)->Arg(TestNumInputs);
+
+BENCHMARK_CAPTURE(BM_ConstructFromRange,
+  deque_size_t,
+  std::deque<size_t>{},
+  getRandomIntegerInputs<size_t>)->Arg(TestNumInputs);
+
+BENCHMARK_CAPTURE(BM_ConstructFromRange,
+  deque_string,
+  std::deque<std::string>{},
+  getRandomStringInputs)->Arg(TestNumInputs);
+
 
 
 
 BENCHMARK_MAIN();

libcxx/benchmarks/vector_operations.bench.cpp

BENCHMARK_CAPTURE(BM_ConstructIterIter,
   std::vector<size_t>{},
   getRandomIntegerInputs<size_t>)->Arg(TestNumInputs);
 
 BENCHMARK_CAPTURE(BM_ConstructIterIter,
   vector_string,
   std::vector<std::string>{},
   getRandomStringInputs)->Arg(TestNumInputs);
 
+BENCHMARK_CAPTURE(BM_ConstructFromRange,
+  vector_char,
+  std::vector<char>{},
+  getRandomIntegerInputs<char>)->Arg(TestNumInputs);
+
+BENCHMARK_CAPTURE(BM_ConstructFromRange,
+  vector_size_t,
+  std::vector<size_t>{},
+  getRandomIntegerInputs<size_t>)->Arg(TestNumInputs);
+
+BENCHMARK_CAPTURE(BM_ConstructFromRange,
+  vector_string,
+  std::vector<std::string>{},
+  getRandomStringInputs)->Arg(TestNumInputs);
+
 
 BENCHMARK_MAIN();