1include(CMakePushCheckState)
2
3include(CheckCompilerFlag OPTIONAL)
4
5if(NOT COMMAND check_compiler_flag)
6  include(CheckCCompilerFlag)
7  include(CheckCXXCompilerFlag)
8endif()
9
10function(llvm_check_compiler_linker_flag lang flag out_var)
11  # If testing a flag with check_c_compiler_flag, it gets added to the compile
12  # command only, but not to the linker command in that test. If the flag
13  # is vital for linking to succeed, the test would fail even if it would
14  # have succeeded if it was included on both commands.
15  #
16  # Therefore, try adding the flag to CMAKE_REQUIRED_FLAGS, which gets
17  # added to both compiling and linking commands in the tests.
18
19  cmake_push_check_state()
20  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${flag}")
21  if(COMMAND check_compiler_flag)
22    check_compiler_flag("${lang}" "" ${out_var})
23  else()
24    # Until the minimum CMAKE version is 3.19
25    # cmake builtin compatible, except we assume lang is C or CXX
26    if("${lang}" STREQUAL "C")
27      check_c_compiler_flag("" ${out_var})
28    elseif("${lang}" STREQUAL "CXX")
29      check_cxx_compiler_flag("" ${out_var})
30    else()
31      message(FATAL_ERROR "\"${lang}\" is not C or CXX")
32    endif()
33  endif()
34  cmake_pop_check_state()
35endfunction()
36