libc/benchmarks/CMakeLists.txt

if(LIBC_TARGET_OS_IS_GPU)
  add_subdirectory(gpu)
  return()
endif()

# The CPU build depends on Google benchmark.
if(NOT LIBC_INCLUDE_BENCHMARKS)
  return()
endif()

find_package(Threads)

set(LLVM_LINK_COMPONENTS
  Support
  TargetParser
  )

#==============================================================================
# Add Unit Testing Support
#==============================================================================

function(add_libc_benchmark_unittest target_name)
  if(NOT LLVM_INCLUDE_TESTS)
    return()
  endif()

  cmake_parse_arguments(
    "LIBC_BENCHMARKS_UNITTEST"
    "" # No optional arguments
    "SUITE" # Single value arguments
    "SRCS;DEPENDS" # Multi-value arguments
    ${ARGN}
  )

  add_executable(${target_name}
    EXCLUDE_FROM_ALL
    ${LIBC_BENCHMARKS_UNITTEST_SRCS}
  )
  target_link_libraries(${target_name}
    PRIVATE
    llvm_gtest_main
    llvm_gtest
    ${LIBC_BENCHMARKS_UNITTEST_DEPENDS}
  )
  llvm_update_compile_flags(${target_name})

  add_custom_command(
    TARGET ${target_name}
    POST_BUILD
    COMMAND $<TARGET_FILE:${target_name}>
  )
  add_dependencies(libc-benchmark-util-tests ${target_name})
endfunction()

#==============================================================================
# Build Google Benchmark for libc
#==============================================================================

include(ExternalProject)
ExternalProject_Add(google-benchmark-libc
        EXCLUDE_FROM_ALL ON
        PREFIX google-benchmark-libc
        SOURCE_DIR ${LLVM_THIRD_PARTY_DIR}/benchmark
        INSTALL_DIR ${CMAKE_CURRENT_BINARY_DIR}/google-benchmark-libc
        CMAKE_CACHE_ARGS
          -DBENCHMARK_ENABLE_EXCEPTIONS:BOOL=OFF
          -DBENCHMARK_ENABLE_LTO:BOOL=OFF
          -DBENCHMARK_ENABLE_TESTING:BOOL=OFF
          -DBENCHMARK_ENABLE_WERROR:BOOL=${LLVM_ENABLE_WERROR}
          -DBENCHMARK_FORCE_WERROR:BOOL=OFF
          -DBENCHMARK_USE_LIBCXX:BOOL=OFF
          -DCMAKE_BUILD_TYPE:STRING=Release

          -DCMAKE_SYSTEM_NAME:STRING=${CMAKE_SYSTEM_NAME}
          -DCMAKE_SYSTEM_PROCESSOR:STRING=${CMAKE_SYSTEM_PROCESSOR}
          -DCMAKE_C_COMPILER:STRING=${CMAKE_C_COMPILER}
          -DCMAKE_CXX_COMPILER:STRING=${CMAKE_CXX_COMPILER}
          -DCMAKE_CXX_FLAGS:STRING=${CMAKE_CXX_FLAGS}
          -DCMAKE_FIND_ROOT_PATH:STRING=${CMAKE_FIND_ROOT_PATH}

          -DBUILD_SHARED_LIBS:BOOL=OFF
          -DCMAKE_EXE_LINKER_FLAGS:STRING=-static

          -DCMAKE_CXX_STANDARD:STRING=14
          -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
        )

add_custom_target(libc-benchmark-util-tests)

# libc-benchmark
add_library(libc-benchmark
    STATIC
    EXCLUDE_FROM_ALL
    LibcBenchmark.cpp
    LibcBenchmark.h
)

target_include_directories(libc-benchmark
    PUBLIC ${LLVM_INCLUDE_DIR} ${LLVM_MAIN_INCLUDE_DIR}
)
target_link_libraries(libc-benchmark
    PUBLIC
    benchmark::benchmark
    LLVMSupport
    LLVMTargetParser
    Threads::Threads
)
add_dependencies(libc-benchmark google-benchmark-libc)
llvm_update_compile_flags(libc-benchmark)

add_libc_benchmark_unittest(libc-benchmark-test
    SRCS LibcBenchmarkTest.cpp
    DEPENDS libc-benchmark
)

# libc-memory-benchmark
add_library(libc-memory-benchmark
    STATIC
    EXCLUDE_FROM_ALL
    LibcMemoryBenchmark.cpp
    LibcMemoryBenchmark.h
    LibcFunctionPrototypes.h
    MemorySizeDistributions.cpp
    MemorySizeDistributions.h
)
target_include_directories(libc-memory-benchmark
    PUBLIC
    ${CMAKE_CURRENT_SOURCE_DIR}
    ${LIBC_SOURCE_DIR}
)
target_link_libraries(libc-memory-benchmark
    PUBLIC
    libc-benchmark
)
llvm_update_compile_flags(libc-memory-benchmark)

add_libc_benchmark_unittest(libc-memory-benchmark-test
    SRCS LibcMemoryBenchmarkTest.cpp
    DEPENDS libc-memory-benchmark
)

# json
add_library(json
    STATIC
    EXCLUDE_FROM_ALL
    JSON.cpp
    JSON.h
)
target_link_libraries(json PUBLIC libc-memory-benchmark)
llvm_update_compile_flags(json)

add_libc_benchmark_unittest(json-test
    SRCS JSONTest.cpp
    DEPENDS json
)

#==============================================================================
# Benchmarking tool
#==============================================================================

# Benchmark all implementations that can run on the target CPU.
function(add_libc_multi_impl_benchmark name)
  get_property(fq_implementations GLOBAL PROPERTY ${name}_implementations)
  foreach(fq_config_name IN LISTS fq_implementations)
    get_target_property(required_cpu_features ${fq_config_name} REQUIRE_CPU_FEATURES)
    cpu_supports(can_run "${required_cpu_features}")
    if(can_run)
        set(benchmark_name ${fq_config_name}_benchmark)
        add_executable(${benchmark_name}
            EXCLUDE_FROM_ALL
            LibcMemoryBenchmarkMain.cpp
        )
        get_target_property(entrypoint_object_file ${fq_config_name} "OBJECT_FILE_RAW")
        target_link_libraries(${benchmark_name} PUBLIC json ${entrypoint_object_file})
        string(TOUPPER ${name} name_upper)
        target_compile_definitions(${benchmark_name} PRIVATE "-DLIBC_BENCHMARK_FUNCTION_${name_upper}=LIBC_NAMESPACE::${name}" "-DLIBC_BENCHMARK_FUNCTION_NAME=\"${fq_config_name}\"")
        llvm_update_compile_flags(${benchmark_name})
    else()
      message(STATUS "Skipping benchmark for '${fq_config_name}' insufficient host cpu features '${required_cpu_features}'")
    endif()
  endforeach()
endfunction()

add_libc_multi_impl_benchmark(bcmp)
add_libc_multi_impl_benchmark(bzero)
add_libc_multi_impl_benchmark(memcmp)
add_libc_multi_impl_benchmark(memcpy)
add_libc_multi_impl_benchmark(memmove)
add_libc_multi_impl_benchmark(memset)

#==============================================================================
# Google Benchmarking tool
#==============================================================================

# This target uses the Google Benchmark facility to report throughput for llvm
# libc memory functions compiled for the host machine. This is useful to
# continuously monitor the performance of the memory functions.
add_executable(libc.benchmarks.memory_functions.opt_host
  EXCLUDE_FROM_ALL
  LibcMemoryGoogleBenchmarkMain.cpp
  LibcDefaultImplementations.cpp
)
target_link_libraries(libc.benchmarks.memory_functions.opt_host
  PRIVATE
  libc-memory-benchmark
  libc.src.string.memcmp_opt_host.__internal__
  libc.src.string.memcpy_opt_host.__internal__
  libc.src.string.memmove_opt_host.__internal__
  libc.src.string.memset_opt_host.__internal__
  libc.src.strings.bcmp_opt_host.__internal__
  libc.src.strings.bzero_opt_host.__internal__
  benchmark_main
)
llvm_update_compile_flags(libc.benchmarks.memory_functions.opt_host)