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[CMake] Unify llvm_check_linker_flag and llvm_check_compiler_linker_flag

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These will be replaced by CMake's check_linker_flag once we update
the minimum CMake version 3.20.

Differential Revision: https://reviews.llvm.org/D145716
This commit is contained in:
Petr Hosek
2023-03-09 18:23:04 +00:00
parent 568be31c9e
commit 55e65ad876
2 changed files with 21 additions and 25 deletions
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39
cmake/Modules/LLVMCheckCompilerLinkerFlag.cmake
View File

@@ -1,28 +1,20 @@
include(CMakePushCheckState)
include(CheckLinkerFlag OPTIONAL)
include(CheckCompilerFlag OPTIONAL)
if (COMMAND check_linker_flag)
macro(llvm_check_compiler_linker_flag)
check_linker_flag(${ARGN})
endmacro()
else()
# Until the minimum CMAKE version is 3.18
if(NOT COMMAND check_compiler_flag)
include(CheckCCompilerFlag)
include(CheckCXXCompilerFlag)
endif()
function(llvm_check_compiler_linker_flag lang flag out_var)
# If testing a flag with check_c_compiler_flag, it gets added to the compile
# command only, but not to the linker command in that test. If the flag
# is vital for linking to succeed, the test would fail even if it would
# have succeeded if it was included on both commands.
#
# Therefore, try adding the flag to CMAKE_REQUIRED_FLAGS, which gets
# added to both compiling and linking commands in the tests.
cmake_push_check_state()
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${flag}")
if(COMMAND check_compiler_flag)
check_compiler_flag("${lang}" "" ${out_var})
else()
# Until the minimum CMAKE version is 3.19
# cmake builtin compatible, except we assume lang is C or CXX
function(llvm_check_compiler_linker_flag lang flag out_var)
cmake_policy(PUSH)
cmake_policy(SET CMP0056 NEW)
set(_CMAKE_EXE_LINKER_FLAGS_SAVE ${CMAKE_EXE_LINKER_FLAGS})
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${flag}")
if("${lang}" STREQUAL "C")
check_c_compiler_flag("" ${out_var})
elseif("${lang}" STREQUAL "CXX")
@@ -30,6 +22,7 @@ function(llvm_check_compiler_linker_flag lang flag out_var)
else()
message(FATAL_ERROR "\"${lang}\" is not C or CXX")
endif()
endif()
cmake_pop_check_state()
endfunction()
set(CMAKE_EXE_LINKER_FLAGS ${_CMAKE_EXE_LINKER_FLAGS_SAVE})
cmake_policy(POP)
endfunction()
endif()

5
runtimes/CMakeLists.txt
View File

@@ -140,8 +140,11 @@ endif()
# Check for -nostdlib++ first; if there's no C++ standard library yet,
# all check_cxx_compiler_flag commands will fail until we add -nostdlib++
# (or -nodefaultlibs).
llvm_check_compiler_linker_flag(CXX "-nostdlib++" CXX_SUPPORTS_NOSTDLIBXX_FLAG)
# TODO: Switch to check_linker_flag after raise the minimum CMake version past 3.14.
check_cxx_compiler_flag(-nostdlib++ CXX_SUPPORTS_NOSTDLIBXX_FLAG)
if (CXX_SUPPORTS_NOSTDLIBXX_FLAG)
# TODO: This is link only flag and should be added to CMAKE_REQUIRED_LINK_OPTIONS
# but that's only supported since CMake 3.14.
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++")
endif()
check_cxx_compiler_flag(-nostdinc++ CXX_SUPPORTS_NOSTDINCXX_FLAG)