CMake/Modules/CMakeTestOBJCXXCompiler.cmake
Brad King 1d21dd0f7c enable_language: Assume compiler works if ABI detection compiles
We run a `try_compile` with a tiny test source to check if the compiler
works so that we can fail early if it does not.  When the compiler does
work, we immediately `try_compile` the ABI detection source.  In the
common case that both steps work, we gain no useful information from the
first one and the work was wasted.

Re-order the checks to try the ABI detection first.  If it works then
assume the compiler works and skip the dedicated check.  If the ABI
check fails then proceed with the normal test for a working compiler so
the diagnostic can be shown as before.

Fixes: #18703
2020-05-25 14:39:40 -04:00

95 lines
3.9 KiB
CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
if(CMAKE_OBJCXX_COMPILER_FORCED)
# The compiler configuration was forced by the user.
# Assume the user has configured all compiler information.
set(CMAKE_OBJCXX_COMPILER_WORKS TRUE)
return()
endif()
include(CMakeTestCompilerCommon)
# work around enforced code signing and / or missing exectuable target type
set(__CMAKE_SAVED_TRY_COMPILE_TARGET_TYPE ${CMAKE_TRY_COMPILE_TARGET_TYPE})
if(_CMAKE_FEATURE_DETECTION_TARGET_TYPE)
set(CMAKE_TRY_COMPILE_TARGET_TYPE ${_CMAKE_FEATURE_DETECTION_TARGET_TYPE})
endif()
# Remove any cached result from an older CMake version.
# We now store this in CMakeOBJCXXCompiler.cmake.
unset(CMAKE_OBJCXX_COMPILER_WORKS CACHE)
# Try to identify the ABI and configure it into CMakeOBJCXXCompiler.cmake
include(${CMAKE_ROOT}/Modules/CMakeDetermineCompilerABI.cmake)
CMAKE_DETERMINE_COMPILER_ABI(OBJCXX ${CMAKE_ROOT}/Modules/CMakeOBJCXXCompilerABI.mm)
if(CMAKE_OBJCXX_ABI_COMPILED)
# The compiler worked so skip dedicated test below.
set(CMAKE_OBJCXX_COMPILER_WORKS TRUE)
message(STATUS "Check for working OBJCXX compiler: ${CMAKE_OBJCXX_COMPILER} - skipped")
endif()
# This file is used by EnableLanguage in cmGlobalGenerator to
# determine that the selected Objective-C++ compiler can actually compile
# and link the most basic of programs. If not, a fatal error
# is set and cmake stops processing commands and will not generate
# any makefiles or projects.
if(NOT CMAKE_OBJCXX_COMPILER_WORKS)
PrintTestCompilerStatus("OBJCXX")
__TestCompiler_setTryCompileTargetType()
file(WRITE ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/testOBJCXXCompiler.mm
"#ifndef __cplusplus\n"
"# error \"The CMAKE_OBJCXX_COMPILER is set to a C compiler\"\n"
"#endif\n"
"#ifndef __OBJC__\n"
"# error \"The CMAKE_OBJCXX_COMPILER is not an Objective-C++ compiler\"\n"
"#endif\n"
"int main(){return 0;}\n")
try_compile(CMAKE_OBJCXX_COMPILER_WORKS ${CMAKE_BINARY_DIR}
${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/testOBJCXXCompiler.mm
OUTPUT_VARIABLE __CMAKE_OBJCXX_COMPILER_OUTPUT)
# Move result from cache to normal variable.
set(CMAKE_OBJCXX_COMPILER_WORKS ${CMAKE_OBJCXX_COMPILER_WORKS})
unset(CMAKE_OBJCXX_COMPILER_WORKS CACHE)
__TestCompiler_restoreTryCompileTargetType()
if(NOT CMAKE_OBJCXX_COMPILER_WORKS)
PrintTestCompilerResult(CHECK_FAIL "broken")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
"Determining if the Objective-C++ compiler works failed with "
"the following output:\n${__CMAKE_OBJCXX_COMPILER_OUTPUT}\n\n")
string(REPLACE "\n" "\n " _output "${__CMAKE_OBJCXX_COMPILER_OUTPUT}")
message(FATAL_ERROR "The Objective-C++ compiler\n \"${CMAKE_OBJCXX_COMPILER}\"\n"
"is not able to compile a simple test program.\nIt fails "
"with the following output:\n ${_output}\n\n"
"CMake will not be able to correctly generate this project.")
endif()
PrintTestCompilerResult(CHECK_PASS "works")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
"Determining if the Objective-C++ compiler works passed with "
"the following output:\n${__CMAKE_OBJCXX_COMPILER_OUTPUT}\n\n")
endif()
# Try to identify the compiler features
include(${CMAKE_ROOT}/Modules/CMakeDetermineCompileFeatures.cmake)
CMAKE_DETERMINE_COMPILE_FEATURES(OBJCXX)
# Re-configure to save learned information.
configure_file(
${CMAKE_ROOT}/Modules/CMakeOBJCXXCompiler.cmake.in
${CMAKE_PLATFORM_INFO_DIR}/CMakeOBJCXXCompiler.cmake
@ONLY
)
include(${CMAKE_PLATFORM_INFO_DIR}/CMakeOBJCXXCompiler.cmake)
if(CMAKE_OBJCXX_SIZEOF_DATA_PTR)
foreach(f ${CMAKE_OBJCXX_ABI_FILES})
include(${f})
endforeach()
unset(CMAKE_OBJCXX_ABI_FILES)
endif()
set(CMAKE_TRY_COMPILE_TARGET_TYPE ${__CMAKE_SAVED_TRY_COMPILE_TARGET_TYPE})
unset(__CMAKE_SAVED_TRY_COMPILE_TARGET_TYPE)
unset(__CMAKE_OBJCXX_COMPILER_OUTPUT)