[cmake] Duplicate {llvm,compiler_rt}_check_linker_flag for runtime libs and llvm

We previously had a few varied definitions of this floating around. I made the one installed with LLVM handle all the cases, and then made the others use it.

This issue was reported to me in https://reviews.llvm.org/D116521#3248117 as
D116521 made clang and llvm use the common cmake utils.

Reviewed By: sebastian-ne, phosek, #libunwind, #libc, #libc_abi, ldionne

Differential Revision: https://reviews.llvm.org/D117537

Author: Ericson2314

cmake/Modules/CheckLinkerFlag.cmake

@@ -1,18 +1,12 @@
 include(CMakePushCheckState)
+include(LLVMCheckLinkerFlag) # Compat until CMake 3.18
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 include(CheckIncludeFiles)
 include(CheckLibraryExists)
 include(CheckSymbolExists)
 include(TestBigEndian)
 
-function(compiler_rt_check_linker_flag flag out_var)
-  cmake_push_check_state()
-  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${flag}")
-  check_cxx_compiler_flag("" ${out_var})
-  cmake_pop_check_state()
-endfunction()
-
 check_library_exists(c fopen "" COMPILER_RT_HAS_LIBC)
 if (COMPILER_RT_USE_BUILTINS_LIBRARY)
   include(HandleCompilerRT)
@@ -171,12 +165,12 @@ check_library_exists(c++ __cxa_throw "" COMPILER_RT_HAS_LIBCXX)
 check_library_exists(stdc++ __cxa_throw "" COMPILER_RT_HAS_LIBSTDCXX)
 
 # Linker flags.
-compiler_rt_check_linker_flag("-Wl,-z,text" COMPILER_RT_HAS_Z_TEXT)
-compiler_rt_check_linker_flag("-fuse-ld=lld" COMPILER_RT_HAS_FUSE_LD_LLD_FLAG)
+llvm_check_linker_flag(CXX "-Wl,-z,text" COMPILER_RT_HAS_Z_TEXT)
+llvm_check_linker_flag(CXX "-fuse-ld=lld" COMPILER_RT_HAS_FUSE_LD_LLD_FLAG)
 
 if(${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
   set(VERS_COMPAT_OPTION "-Wl,-z,gnu-version-script-compat")
-  compiler_rt_check_linker_flag("${VERS_COMPAT_OPTION}" COMPILER_RT_HAS_GNU_VERSION_SCRIPT_COMPAT)
+  llvm_check_linker_flag(CXX "${VERS_COMPAT_OPTION}" COMPILER_RT_HAS_GNU_VERSION_SCRIPT_COMPAT)
 endif()
 
 set(DUMMY_VERS ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/dummy.vers)
@@ -187,10 +181,10 @@ if(COMPILER_RT_HAS_GNU_VERSION_SCRIPT_COMPAT)
   # -z gnu-version-script-compat.
   string(APPEND VERS_OPTION " ${VERS_COMPAT_OPTION}")
 endif()
-compiler_rt_check_linker_flag("${VERS_OPTION}" COMPILER_RT_HAS_VERSION_SCRIPT)
+llvm_check_linker_flag(CXX "${VERS_OPTION}" COMPILER_RT_HAS_VERSION_SCRIPT)
 
 if(ANDROID)
-  compiler_rt_check_linker_flag("-Wl,-z,global" COMPILER_RT_HAS_Z_GLOBAL)
+  llvm_check_linker_flag(CXX "-Wl,-z,global" COMPILER_RT_HAS_Z_GLOBAL)
   check_library_exists(log __android_log_write "" COMPILER_RT_HAS_LIBLOG)
 endif()
 
@@ -436,7 +430,7 @@ if(APPLE)
     -lc++
     -lc++abi)
 
-  compiler_rt_check_linker_flag("-fapplication-extension" COMPILER_RT_HAS_APP_EXTENSION)
+  llvm_check_linker_flag(CXX "-fapplication-extension" COMPILER_RT_HAS_APP_EXTENSION)
   if(COMPILER_RT_HAS_APP_EXTENSION)
     list(APPEND DARWIN_COMMON_LINK_FLAGS "-fapplication-extension")
   endif()

compiler-rt/cmake/config-ix.cmake

@@ -1,6 +1,6 @@
 include(CMakePushCheckState)
 include(CheckLibraryExists)
-include(CheckLinkerFlag)
+include(LLVMCheckLinkerFlag) # Compat until CMake 3.18
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 include(CheckCSourceCompiles)
@@ -12,7 +12,7 @@ include(CheckCSourceCompiles)
 # libunwind (and the compiler implicit -lunwind wouldn't succeed as the newly
 # built libunwind isn't installed yet). For those cases, it'd be good to
 # link with --uwnindlib=none. Check if that option works.
-llvm_check_linker_flag("--unwindlib=none" LIBCXX_SUPPORTS_UNWINDLIB_NONE_FLAG)
+llvm_check_linker_flag(C "--unwindlib=none" LIBCXX_SUPPORTS_UNWINDLIB_NONE_FLAG)
 if (LIBCXX_SUPPORTS_UNWINDLIB_NONE_FLAG)
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} --unwindlib=none")
 endif()

libcxx/cmake/config-ix.cmake

@@ -2,14 +2,14 @@ include(CMakePushCheckState)
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 include(CheckLibraryExists)
-include(CheckLinkerFlag)
+include(LLVMCheckLinkerFlag) # Compat until CMake 3.18
 include(CheckSymbolExists)
 include(CheckCSourceCompiles)
 
 # The compiler driver may be implicitly trying to link against libunwind, which
 # might not work if libunwind doesn't exist yet. Try to check if
 # --unwindlib=none is supported, and use that if possible.
-llvm_check_linker_flag("--unwindlib=none" LIBUNWIND_SUPPORTS_UNWINDLIB_NONE_FLAG)
+llvm_check_linker_flag(C "--unwindlib=none" LIBUNWIND_SUPPORTS_UNWINDLIB_NONE_FLAG)
 if (LIBUNWIND_SUPPORTS_UNWINDLIB_NONE_FLAG)
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} --unwindlib=none")
 endif()
@@ -34,11 +34,11 @@ endif()
 # required for the link to go through. We remove sanitizers from the
 # configuration checks to avoid spurious link errors.
 
-llvm_check_linker_flag(-nostdlib++ LIBUNWIND_SUPPORTS_NOSTDLIBXX_FLAG)
+llvm_check_linker_flag(C "-nostdlib++" LIBUNWIND_SUPPORTS_NOSTDLIBXX_FLAG)
 if (LIBUNWIND_SUPPORTS_NOSTDLIBXX_FLAG)
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++")
 else()
-  llvm_check_linker_flag(-nodefaultlibs LIBUNWIND_SUPPORTS_NODEFAULTLIBS_FLAG)
+  llvm_check_linker_flag(C "-nodefaultlibs" LIBUNWIND_SUPPORTS_NODEFAULTLIBS_FLAG)
   if (LIBUNWIND_SUPPORTS_NODEFAULTLIBS_FLAG)
     set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nodefaultlibs")
   endif()

libunwind/cmake/config-ix.cmake

@@ -5,14 +5,22 @@ if (COMMAND check_linker_flag)
     check_linker_flag(${ARGN})
   endmacro()
 else()
+  # Until the minimum CMAKE version is 3.18
+
   include(CheckCXXCompilerFlag)
   include(CMakePushCheckState)
 
-  # cmake builtin compatible, except we assume lang is CXX
+  # cmake builtin compatible, except we assume lang is C or CXX
   function(llvm_check_linker_flag lang flag out_var)
     cmake_push_check_state()
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${flag}")
-    check_cxx_compiler_flag("" ${out_var})
+    if("${lang}" STREQUAL "C")
+      check_c_compiler_flag("" ${out_var})
+    elseif("${lang}" STREQUAL "CXX")
+      check_cxx_compiler_flag("" ${out_var})
+    else()
+      message(FATAL_ERROR "\"${lang}\" is not C or CXX")
+    endif()
     cmake_pop_check_state()
   endfunction()
 endif()

llvm/cmake/modules/LLVMCheckLinkerFlag.cmake

@@ -88,7 +88,7 @@ set(LLVM_CMAKE_DIR ${LLVM_MAIN_SRC_DIR}/cmake/modules)
 set(LLVM_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../llvm)
 
 include(CheckLibraryExists)
-include(CheckLinkerFlag)
+include(LLVMCheckLinkerFlag) # Compat until CMake 3.18
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 
@@ -100,7 +100,7 @@ if (NOT LLVM_RUNTIMES_LINKING_WORKS)
   # --unwindlib=none is supported, and use that if possible.
   # Don't add this if not necessary to fix linking, as it can break using
   # e.g. ASAN/TSAN.
-  llvm_check_linker_flag("--unwindlib=none" LLVM_RUNTIMES_SUPPORT_UNWINDLIB_NONE_FLAG)
+  llvm_check_linker_flag(C "--unwindlib=none" LLVM_RUNTIMES_SUPPORT_UNWINDLIB_NONE_FLAG)
   if (LLVM_RUNTIMES_SUPPORT_UNWINDLIB_NONE_FLAG)
     set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} --unwindlib=none")
   endif()
@@ -110,7 +110,7 @@ endif()
 # Check for -nostdlib++ first; if there's no C++ standard library yet,
 # all check_cxx_compiler_flag commands will fail until we add -nostdlib++
 # (or -nodefaultlibs).
-llvm_check_linker_flag(-nostdlib++ LLVM_RUNTIMES_SUPPORT_NOSTDLIBXX_FLAG)
+llvm_check_linker_flag(C "-nostdlib++" LLVM_RUNTIMES_SUPPORT_NOSTDLIBXX_FLAG)
 if (LLVM_RUNTIMES_SUPPORT_NOSTDLIBXX_FLAG)
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++")
 endif()