[libc++] Remove special handling of the native C++ library in benchmarks

libcxx/CMakeLists.txt

@@ -159,20 +159,6 @@ set(LIBCXX_BENCHMARK_TEST_ARGS_DEFAULT --benchmark_min_time=0.01)
 set(LIBCXX_BENCHMARK_TEST_ARGS "${LIBCXX_BENCHMARK_TEST_ARGS_DEFAULT}" CACHE STRING
     "Arguments to pass when running the benchmarks using check-cxx-benchmarks")
 
-set(LIBCXX_BENCHMARK_NATIVE_STDLIB "" CACHE STRING
-        "Build the benchmarks against the specified native STL.
-         The value must be one of libc++/libstdc++")
-set(LIBCXX_BENCHMARK_NATIVE_GCC_TOOLCHAIN "" CACHE STRING
-    "Use alternate GCC toolchain when building the native benchmarks")
-
-if (LIBCXX_BENCHMARK_NATIVE_STDLIB)
-  if (NOT (LIBCXX_BENCHMARK_NATIVE_STDLIB STREQUAL "libc++"
-        OR LIBCXX_BENCHMARK_NATIVE_STDLIB STREQUAL "libstdc++"))
-    message(FATAL_ERROR "Invalid value for LIBCXX_BENCHMARK_NATIVE_STDLIB: "
-            "'${LIBCXX_BENCHMARK_NATIVE_STDLIB}'")
-  endif()
-endif()
-
 option(LIBCXX_INCLUDE_DOCS "Build the libc++ documentation." ${LLVM_INCLUDE_DOCS})
 set(LIBCXX_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}" CACHE STRING
     "Define suffix of library directory name (32/64)")

libcxx/benchmarks/CMakeLists.txt

@@ -2,12 +2,12 @@ include(ExternalProject)
 include(CheckCXXCompilerFlag)
 
 #==============================================================================
-# Build Google Benchmark for libc++
+# Build Google Benchmark
 #==============================================================================
 
 set(CMAKE_FOLDER "${CMAKE_FOLDER}/Benchmarks")
 
-set(BENCHMARK_LIBCXX_COMPILE_FLAGS
+set(BENCHMARK_COMPILE_FLAGS
     -Wno-unused-command-line-argument
     -nostdinc++
     -isystem "${LIBCXX_GENERATED_INCLUDE_DIR}"
@@ -16,64 +16,37 @@ set(BENCHMARK_LIBCXX_COMPILE_FLAGS
     ${SANITIZER_FLAGS}
     )
 if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
-  list(APPEND BENCHMARK_LIBCXX_COMPILE_FLAGS
+  list(APPEND BENCHMARK_COMPILE_FLAGS
     -isystem "${LIBCXX_GENERATED_INCLUDE_TARGET_DIR}")
 endif()
 if (DEFINED LIBCXX_CXX_ABI_LIBRARY_PATH)
-  list(APPEND BENCHMARK_LIBCXX_COMPILE_FLAGS
+  list(APPEND BENCHMARK_COMPILE_FLAGS
           -L${LIBCXX_CXX_ABI_LIBRARY_PATH}
           -Wl,-rpath,${LIBCXX_CXX_ABI_LIBRARY_PATH})
 endif()
-split_list(BENCHMARK_LIBCXX_COMPILE_FLAGS)
+split_list(BENCHMARK_COMPILE_FLAGS)
 
-ExternalProject_Add(google-benchmark-libcxx
+ExternalProject_Add(google-benchmark
         EXCLUDE_FROM_ALL ON
         DEPENDS cxx cxx-headers
-        PREFIX benchmark-libcxx
+        PREFIX google-benchmark
         SOURCE_DIR ${LLVM_THIRD_PARTY_DIR}/benchmark
-        INSTALL_DIR ${CMAKE_CURRENT_BINARY_DIR}/benchmark-libcxx
+        INSTALL_DIR ${CMAKE_CURRENT_BINARY_DIR}/google-benchmark
         CMAKE_CACHE_ARGS
           -DCMAKE_C_COMPILER:STRING=${CMAKE_C_COMPILER}
           -DCMAKE_CXX_COMPILER:STRING=${CMAKE_CXX_COMPILER}
           -DCMAKE_BUILD_TYPE:STRING=RELEASE
           -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
-          -DCMAKE_CXX_FLAGS:STRING=${BENCHMARK_LIBCXX_COMPILE_FLAGS}
+          -DCMAKE_CXX_FLAGS:STRING=${BENCHMARK_COMPILE_FLAGS}
           -DBENCHMARK_USE_LIBCXX:BOOL=ON
           -DBENCHMARK_ENABLE_TESTING:BOOL=OFF)
 
-#==============================================================================
-# Build Google Benchmark for the native stdlib
-#==============================================================================
-set(BENCHMARK_NATIVE_TARGET_FLAGS)
-if (LIBCXX_BENCHMARK_NATIVE_GCC_TOOLCHAIN)
-  set(BENCHMARK_NATIVE_TARGET_FLAGS
-      --gcc-toolchain=${LIBCXX_BENCHMARK_NATIVE_GCC_TOOLCHAIN})
-endif()
-split_list(BENCHMARK_NATIVE_TARGET_FLAGS)
-
-if (LIBCXX_BENCHMARK_NATIVE_STDLIB)
-  ExternalProject_Add(google-benchmark-native
-        EXCLUDE_FROM_ALL ON
-        PREFIX benchmark-native
-        SOURCE_DIR ${LLVM_THIRD_PARTY_DIR}/benchmark
-        INSTALL_DIR ${CMAKE_CURRENT_BINARY_DIR}/benchmark-native
-        CMAKE_CACHE_ARGS
-          -DCMAKE_C_COMPILER:STRING=${CMAKE_C_COMPILER}
-          -DCMAKE_CXX_COMPILER:STRING=${CMAKE_CXX_COMPILER}
-          -DCMAKE_CXX_FLAGS:STRING=${BENCHMARK_NATIVE_TARGET_FLAGS}
-          -DCMAKE_BUILD_TYPE:STRING=RELEASE
-          -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
-          -DBENCHMARK_ENABLE_TESTING:BOOL=OFF)
-endif()
-
-
 #==============================================================================
 # 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)
+set(BENCHMARK_INSTALL_DIR ${CMAKE_CURRENT_BINARY_DIR}/google-benchmark)
 
 add_library(               cxx-benchmarks-flags INTERFACE)
 
@@ -97,41 +70,23 @@ else()
   target_compile_features( cxx-benchmarks-flags INTERFACE cxx_std_23)
 endif()
 
-target_compile_options(    cxx-benchmarks-flags INTERFACE -fsized-deallocation -nostdinc++)
+target_compile_options(cxx-benchmarks-flags INTERFACE -fsized-deallocation -nostdinc++
+                                                      ${SANITIZER_FLAGS} -Wno-user-defined-literals -Wno-suggest-override)
 target_include_directories(cxx-benchmarks-flags INTERFACE "${LIBCXX_GENERATED_INCLUDE_DIR}"
-                                                INTERFACE "${BENCHMARK_LIBCXX_INSTALL}/include"
+                                                INTERFACE "${BENCHMARK_INSTALL_DIR}/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)
-    target_link_libraries(cxx-benchmarks-flags-native INTERFACE -lstdc++fs)
-  endif()
-else()
-  target_link_libraries(cxx-benchmarks-flags-native INTERFACE -lc++fs -lc++experimental)
-endif()
-
-add_library(           cxx-benchmarks-flags-libcxx INTERFACE)
-target_link_libraries( cxx-benchmarks-flags-libcxx INTERFACE cxx-benchmarks-flags)
-target_compile_options(cxx-benchmarks-flags-libcxx INTERFACE ${SANITIZER_FLAGS} -Wno-user-defined-literals -Wno-suggest-override)
-target_link_options(   cxx-benchmarks-flags-libcxx INTERFACE -lm -nostdlib++ "-L${BENCHMARK_LIBCXX_INSTALL}/lib" "-L${BENCHMARK_LIBCXX_INSTALL}/lib64" ${SANITIZER_FLAGS})
+target_link_options(cxx-benchmarks-flags INTERFACE -lm -nostdlib++
+                                                   "-L${BENCHMARK_INSTALL_DIR}/lib" "-L${BENCHMARK_INSTALL_DIR}/lib64"
+                                                   ${SANITIZER_FLAGS})
 
 set(libcxx_benchmark_targets)
 
 function(add_benchmark_test name source_file)
   set(libcxx_target ${name}_libcxx)
   list(APPEND libcxx_benchmark_targets ${libcxx_target})
   add_executable(${libcxx_target} EXCLUDE_FROM_ALL ${source_file})
-  target_link_libraries(${libcxx_target} PRIVATE cxx-benchmarks-flags-libcxx)
-  add_dependencies(${libcxx_target} cxx google-benchmark-libcxx)
+  target_link_libraries(${libcxx_target} PRIVATE cxx-benchmarks-flags)
+  add_dependencies(${libcxx_target} cxx google-benchmark)
   add_dependencies(cxx-benchmarks ${libcxx_target})
   if (LIBCXX_ENABLE_SHARED)
     target_link_libraries(${libcxx_target} PRIVATE cxx_shared)
@@ -144,27 +99,10 @@ function(add_benchmark_test name source_file)
   endif()
   set_target_properties(${libcxx_target}
     PROPERTIES
-          OUTPUT_NAME "${name}.libcxx.out"
+          OUTPUT_NAME "${name}.bench.out"
           RUNTIME_OUTPUT_DIRECTORY "${BENCHMARK_OUTPUT_DIR}"
           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_EXTENSIONS NO)
-  endif()
 endfunction()
 
 

libcxx/benchmarks/lit.cfg.py

@@ -19,5 +19,5 @@
 config.test_source_root = config.test_exec_root
 
 config.test_format = GoogleBenchmark(
-    test_sub_dirs=".", test_suffix=".libcxx.out", benchmark_args=config.benchmark_args
+    test_sub_dirs=".", test_suffix=".bench.out", benchmark_args=config.benchmark_args
 )

libcxx/docs/BuildingLibcxx.rst

@@ -399,22 +399,6 @@ libc++ Feature Options
   since the primary use of ``check-cxx-benchmarks`` is to get test and sanitizer coverage, not to
   get accurate measurements.
 
-.. option:: LIBCXX_BENCHMARK_NATIVE_STDLIB:STRING
-
-  **Default**:: ``""``
-
-  **Values**:: ``libc++``, ``libstdc++``
-
-  Build the libc++ benchmark tests and Google Benchmark library against the
-  specified standard library on the platform. On Linux this can be used to
-  compare libc++ to libstdc++ by building the benchmark tests against both
-  standard libraries.
-
-.. option:: LIBCXX_BENCHMARK_NATIVE_GCC_TOOLCHAIN:STRING
-
-  Use the specified GCC toolchain and standard library when building the native
-  stdlib benchmark tests.
-
 .. option:: LIBCXX_ASSERTION_HANDLER_FILE:PATH
 
   **Default**:: ``"${CMAKE_CURRENT_SOURCE_DIR}/vendor/llvm/default_assertion_handler.in"``

libcxx/docs/ReleaseNotes/19.rst

@@ -169,3 +169,7 @@ Build System Changes
   to automatically detect the presence of ``clang-tidy`` and the required ``Clang`` libraries.
 
 - The CMake options ``LIBCXX_INSTALL_MODULES`` now defaults to ``ON``.
+
+- The CMake options ``LIBCXX_BENCHMARK_NATIVE_STDLIB`` and ``LIBCXX_BENCHMARK_NATIVE_GCC_TOOLCHAIN`` have
+  been removed. To benchmark the native standard library, configure the test suite against the native
+  standard library directly instead.

libcxx/docs/TestingLibcxx.rst

@@ -351,7 +351,7 @@ Test Filenames`_ when determining the names for new test files.
      - Same as ``FOO.pass.cpp``, but for Objective-C++.
 
    * - ``FOO.compile.pass.cpp``
-     - Checks whether the C++ code in the file compiles successfully. In general, prefer ``compile`` tests over ``verify`` tests, 
+     - Checks whether the C++ code in the file compiles successfully. In general, prefer ``compile`` tests over ``verify`` tests,
        subject to the specific recommendations, below, for when to write ``verify`` tests.
    * - ``FOO.compile.pass.mm``
      - Same as ``FOO.compile.pass.cpp``, but for Objective-C++.
@@ -447,19 +447,12 @@ An example build would look like:
 
 .. code-block:: bash
 
-  $ cd build
-  $ ninja cxx-benchmarks
+  $ ninja -C build cxx-benchmarks
 
 This will build all of the benchmarks under ``<libcxx-src>/benchmarks`` to be
 built against the just-built libc++. The compiled tests are output into
 ``build/projects/libcxx/benchmarks``.
 
-The benchmarks can also be built against the platforms native standard library
-using the ``-DLIBCXX_BUILD_BENCHMARKS_NATIVE_STDLIB=ON`` CMake option. This
-is useful for comparing the performance of libc++ to other standard libraries.
-The compiled benchmarks are named ``<test>.libcxx.out`` if they test libc++ and
-``<test>.native.out`` otherwise.
-
 Also See:
 
   * :ref:`Building Libc++ <build instructions>`
@@ -476,8 +469,8 @@ For example:
 .. code-block:: bash
 
   $ cd build/projects/libcxx/benchmarks
-  $ ./algorithms.libcxx.out # Runs all the benchmarks
-  $ ./algorithms.libcxx.out --benchmark_filter=BM_Sort.* # Only runs the sort benchmarks
+  $ ./algorithms.out # Runs all the benchmarks
+  $ ./algorithms.out --benchmark_filter=BM_Sort.* # Only runs the sort benchmarks
 
 For more information about running benchmarks see `Google Benchmark`_.