[compiler-rt][libunwind][runtimes] Recategorize `llvm_check_linker_flag` langs

[Ericson2314]

Summary

Done according to @phosek's comments in D117537, but not done then to
separate pure refactor (that) from possible behavior change (this).

Wasn't working before, but I think that was due to an issue of mismatched variable names fixed in D110005.

[Ericson2314]

rebase on top of new version of D117537

[Ericson2314]

1. Updating D117833: [compiler-rt][libunwind][runtimes] Recategorize llvm_check_linker_flag langs #
2. Enter a brief description of the changes included in this update.
3. The first line is used as subject, next lines as comment. #
4. If you intended to create a new revision, use:
5. $ arc diff --create

rebase after last round changed

[phosek]

LGTM

[Ericson2314]

Rebase to retrigger CI now that parent landed

[Ericson2314]

Hmm, might these errors be legitimate?

[Ericson2314]

Rebase. I think this might work now that D110005 has landed.

[Ericson2314]

Rebase

[Ericson2314]

Rebase

[Ericson2314]

Rebase

[Ericson2314]

Rebase

[Ericson2314]

Rebase

[Ericson2314]

@ldionne Since you reviewed D130586 which contains this, might you review this? Then I'll have a libc++ reviewer and can land it.

[Ericson2314]

The change outside compiler-rt was so trivial I decided to go chaotic good on this one.

compiler-rt/cmake/config-ix.cmake

 if (ANDROID AND COMPILER_RT_HAS_LIBDL)
   # Android's libstdc++ has a dependency on libdl.
   list(APPEND CMAKE_REQUIRED_LIBRARIES dl)
 endif()
 check_library_exists(c++ __cxa_throw "" COMPILER_RT_HAS_LIBCXX)
 check_library_exists(stdc++ __cxa_throw "" COMPILER_RT_HAS_LIBSTDCXX)
 
 # Linker flags.
-llvm_check_compiler_linker_flag(CXX "-Wl,-z,text" COMPILER_RT_HAS_Z_TEXT)
-llvm_check_compiler_linker_flag(CXX "-fuse-ld=lld" COMPILER_RT_HAS_FUSE_LD_LLD_FLAG)
+llvm_check_compiler_linker_flag(C "-Wl,-z,text" COMPILER_RT_HAS_Z_TEXT)
+llvm_check_compiler_linker_flag(C "-fuse-ld=lld" COMPILER_RT_HAS_FUSE_LD_LLD_FLAG)
 
 if(${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
   set(VERS_COMPAT_OPTION "-Wl,-z,gnu-version-script-compat")
-  llvm_check_compiler_linker_flag(CXX "${VERS_COMPAT_OPTION}" COMPILER_RT_HAS_GNU_VERSION_SCRIPT_COMPAT)
+  llvm_check_compiler_linker_flag(C "${VERS_COMPAT_OPTION}" COMPILER_RT_HAS_GNU_VERSION_SCRIPT_COMPAT)
 endif()
 
 set(DUMMY_VERS ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/dummy.vers)
 file(WRITE ${DUMMY_VERS} "{};")
 set(VERS_OPTION "-Wl,--version-script,${DUMMY_VERS}")
 if(COMPILER_RT_HAS_GNU_VERSION_SCRIPT_COMPAT)
   # Solaris 11.4 ld only supports --version-script with
   # -z gnu-version-script-compat.
   string(APPEND VERS_OPTION " ${VERS_COMPAT_OPTION}")
 endif()
-llvm_check_compiler_linker_flag(CXX "${VERS_OPTION}" COMPILER_RT_HAS_VERSION_SCRIPT)
+llvm_check_compiler_linker_flag(C "${VERS_OPTION}" COMPILER_RT_HAS_VERSION_SCRIPT)
 
 if(ANDROID)
-  llvm_check_compiler_linker_flag(CXX "-Wl,-z,global" COMPILER_RT_HAS_Z_GLOBAL)
+  llvm_check_compiler_linker_flag(C "-Wl,-z,global" COMPILER_RT_HAS_Z_GLOBAL)
   check_library_exists(log __android_log_write "" COMPILER_RT_HAS_LIBLOG)
 endif()
 
 # Architectures.
 
 # List of all architectures we can target.
 set(COMPILER_RT_SUPPORTED_ARCH)
 
if(APPLE)
   set(CMAKE_OSX_DEPLOYMENT_TARGET "")
 
   set(DARWIN_COMMON_CFLAGS -stdlib=libc++)
   set(DARWIN_COMMON_LINK_FLAGS
     -stdlib=libc++
     -lc++
     -lc++abi)
 
-  llvm_check_compiler_linker_flag(CXX "-fapplication-extension" COMPILER_RT_HAS_APP_EXTENSION)
+  llvm_check_compiler_linker_flag(C "-fapplication-extension" COMPILER_RT_HAS_APP_EXTENSION)
   if(COMPILER_RT_HAS_APP_EXTENSION)
     list(APPEND DARWIN_COMMON_LINK_FLAGS "-fapplication-extension")
   endif()
 
   set(DARWIN_osx_CFLAGS
     ${DARWIN_COMMON_CFLAGS}
     ${DARWIN_osx_MIN_VER_FLAG}=${SANITIZER_MIN_OSX_VERSION})
   set(DARWIN_osx_LINK_FLAGS

libunwind/cmake/config-ix.cmake

 # otherwise -nodefaultlibs is used. We want all our checks to also
 # use one of these options, otherwise we may end up with an inconsistency between
 # the flags we think we require during configuration (if the checks are
 # performed without one of those options) and the flags that are actually
 # required during compilation (which has the -nostdlib++ or -nodefaultlibs). libc is
 # required for the link to go through. We remove sanitizers from the
 # configuration checks to avoid spurious link errors.
 
-llvm_check_compiler_linker_flag(C "-nostdlib++" CXX_SUPPORTS_NOSTDLIBXX_FLAG)
+llvm_check_compiler_linker_flag(CXX "-nostdlib++" CXX_SUPPORTS_NOSTDLIBXX_FLAG)
 if (CXX_SUPPORTS_NOSTDLIBXX_FLAG)
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++")
 else()
   llvm_check_compiler_linker_flag(C "-nodefaultlibs" C_SUPPORTS_NODEFAULTLIBS_FLAG)
   if (C_SUPPORTS_NODEFAULTLIBS_FLAG)
     set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nodefaultlibs")
   endif()
 endif()

runtimes/CMakeLists.txt

if (CXX_SUPPORTS_UNWINDLIB_EQ_NONE_FLAG)
     endif()
   endif()
 endif()
 
 # Disable use of the installed C++ standard library when building runtimes.
 # 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(C "-nostdlib++" CXX_SUPPORTS_NOSTDLIBXX_FLAG)
+llvm_check_compiler_linker_flag(CXX "-nostdlib++" CXX_SUPPORTS_NOSTDLIBXX_FLAG)
 if (CXX_SUPPORTS_NOSTDLIBXX_FLAG)
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++")
 endif()
 check_cxx_compiler_flag(-nostdinc++ CXX_SUPPORTS_NOSTDINCXX_FLAG)
 if (CXX_SUPPORTS_NOSTDINCXX_FLAG)
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdinc++")
 endif()