Factor the option and checking of compiler version better. Put the

option with the others in the top level CMakeLists, and put the check in
HandleLLVMOptions. This will also let it be used from the standalone
Clang builds.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199149 91177308-0d34-0410-b5e6-96231b3b80d8

Author: chandlerc

CMakeLists.txt

@@ -195,6 +195,9 @@ else()
   option(LLVM_ENABLE_ASSERTIONS "Enable assertions" ON)
 endif()
 
+option(LLVM_FORCE_USE_OLD_HOST_TOOLCHAIN
+       "Set to ON to force using an old, unsupported host toolchain." OFF)
+
 option(LLVM_USE_INTEL_JITEVENTS
   "Use Intel JIT API to inform Intel(R) VTune(TM) Amplifier XE 2011 about JIT code"
   OFF)

cmake/config-ix.cmake

@@ -316,25 +316,6 @@ if (LIBXML2_FOUND)
   endif ()
 endif ()
 
-option(LLVM_FORCE_USE_OLD_TOOLCHAIN
-       "Set to ON if you want to force CMake to use a toolchain older than those supported by LLVM."
-       OFF)
-if(NOT LLVM_FORCE_USE_OLD_TOOLCHAIN)
-  if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
-      message(FATAL_ERROR "Host GCC version must be at least 4.7!")
-    endif()
-  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.1)
-      message(FATAL_ERROR "Host Clang version must be at least 3.1!")
-    endif()
-  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 17.0)
-      message(FATAL_ERROR "Host Visual Studio must be at least 2012 (MSVC 17.0)")
-    endif()
-  endif()
-endif()
-
 include(CheckCXXCompilerFlag)
 
 check_cxx_compiler_flag("-Wno-variadic-macros" SUPPORTS_NO_VARIADIC_MACROS_FLAG)

cmake/modules/HandleLLVMOptions.cmake

@@ -14,6 +14,22 @@ elseif( "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" )
   set(LLVM_COMPILER_IS_GCC_COMPATIBLE ON)
 endif()
 
+if(NOT LLVM_FORCE_USE_OLD_TOOLCHAIN)
+  if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
+      message(FATAL_ERROR "Host GCC version must be at least 4.7!")
+    endif()
+  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.1)
+      message(FATAL_ERROR "Host Clang version must be at least 3.1!")
+    endif()
+  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 17.0)
+      message(FATAL_ERROR "Host Visual Studio must be at least 2012 (MSVC 17.0)")
+    endif()
+  endif()
+endif()
+
 if( LLVM_ENABLE_ASSERTIONS )
   # MSVC doesn't like _DEBUG on release builds. See PR 4379.
   if( NOT MSVC )