benchmark/cmake/CXXFeatureCheck.cmake
Dominic Hamon 974cd5a5c5
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.
2022-08-04 15:33:35 +01:00

73 lines
2.3 KiB
CMake

# - Compile and run code to check for C++ features
#
# This functions compiles a source file under the `cmake` folder
# and adds the corresponding `HAVE_[FILENAME]` flag to the CMake
# environment
#
# cxx_feature_check(<FLAG> [<VARIANT>])
#
# - Example
#
# include(CXXFeatureCheck)
# cxx_feature_check(STD_REGEX)
# Requires CMake 2.8.12+
if(__cxx_feature_check)
return()
endif()
set(__cxx_feature_check INCLUDED)
function(cxx_feature_check FILE)
string(TOLOWER ${FILE} FILE)
string(TOUPPER ${FILE} VAR)
string(TOUPPER "HAVE_${VAR}" FEATURE)
if (DEFINED HAVE_${VAR})
set(HAVE_${VAR} 1 PARENT_SCOPE)
add_definitions(-DHAVE_${VAR})
return()
endif()
set(FEATURE_CHECK_CMAKE_FLAGS ${BENCHMARK_CXX_LINKER_FLAGS})
if (ARGC GREATER 1)
message(STATUS "Enabling additional flags: ${ARGV1}")
list(APPEND FEATURE_CHECK_CMAKE_FLAGS ${ARGV1})
endif()
if (NOT DEFINED COMPILE_${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 ${FEATURE_CHECK_CMAKE_FLAGS}
LINK_LIBRARIES ${BENCHMARK_CXX_LIBRARIES}
OUTPUT_VARIABLE COMPILE_OUTPUT_VAR)
if(COMPILE_${FEATURE})
message(WARNING
"If you see build failures due to cross compilation, try setting HAVE_${VAR} to 0")
set(RUN_${FEATURE} 0 CACHE INTERNAL "")
else()
set(RUN_${FEATURE} 1 CACHE INTERNAL "")
endif()
else()
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 ${FEATURE_CHECK_CMAKE_FLAGS}
LINK_LIBRARIES ${BENCHMARK_CXX_LIBRARIES}
COMPILE_OUTPUT_VARIABLE COMPILE_OUTPUT_VAR)
endif()
endif()
if(RUN_${FEATURE} EQUAL 0)
message(STATUS "Performing Test ${FEATURE} -- success")
set(HAVE_${VAR} 1 PARENT_SCOPE)
add_definitions(-DHAVE_${VAR})
else()
if(NOT COMPILE_${FEATURE})
message(STATUS "Performing Test ${FEATURE} -- failed to compile: ${COMPILE_OUTPUT_VAR}")
else()
message(STATUS "Performing Test ${FEATURE} -- compiled but failed to run")
endif()
endif()
endfunction()