New system for choosing CRT type on MSVC.
Is setted on a per build type basis. This is useful for generators
that comprise several build types, i.e. VC++ solutions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110296 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/cmake/modules/ChooseMSVCCRT.cmake b/cmake/modules/ChooseMSVCCRT.cmake
new file mode 100644
index 0000000..eb78f45
--- /dev/null
+++ b/cmake/modules/ChooseMSVCCRT.cmake
@@ -0,0 +1,106 @@
+# The macro choose_msvc_crt() takes a list of possible
+# C runtimes to choose from, in the form of compiler flags,
+# to present to the user. (MTd for /MTd, etc)
+#
+# The macro is invoked at the end of the file.
+#
+# CMake already sets CRT flags in the CMAKE_CXX_FLAGS_* and
+# CMAKE_C_FLAGS_* variables by default. To let the user
+# override that for each build type:
+# 1. Detect which CRT is already selected, and reflect this in
+# LLVM_USE_CRT_* so the user can have a better idea of what
+# changes they're making.
+# 2. Replace the flags in both variables with the new flag via a regex.
+# 3. set() the variables back into the cache so the changes
+# are user-visible.
+
+### Helper macros: ###
+macro(make_crt_regex regex crts)
+ set(${regex} "")
+ foreach(crt ${${crts}})
+ # Trying to match the beginning or end of the string with stuff
+ # like [ ^]+ didn't work, so use a bunch of parentheses instead.
+ set(${regex} "${${regex}}|(^| +)/${crt}($| +)")
+ endforeach(crt)
+ string(REGEX REPLACE "^\\|" "" ${regex} "${${regex}}")
+endmacro(make_crt_regex)
+
+macro(get_current_crt crt_current regex flagsvar)
+ # Find the selected-by-CMake CRT for each build type, if any.
+ # Strip off the leading slash and any whitespace.
+ string(REGEX MATCH "${${regex}}" ${crt_current} "${${flagsvar}}")
+ string(REPLACE "/" " " ${crt_current} "${${crt_current}}")
+ string(STRIP "${${crt_current}}" ${crt_current})
+endmacro(get_current_crt)
+
+# Replaces or adds a flag to a variable.
+# Expects 'flag' to be padded with spaces.
+macro(set_flag_in_var flagsvar regex flag)
+ string(REGEX MATCH "${${regex}}" current_flag "${${flagsvar}}")
+ if("${current_flag}" STREQUAL "")
+ set(${flagsvar} "${${flagsvar}}${${flag}}")
+ else()
+ string(REGEX REPLACE "${${regex}}" "${${flag}}" ${flagsvar} "${${flagsvar}}")
+ endif()
+ string(STRIP "${${flagsvar}}" ${flagsvar})
+ # Make sure this change gets reflected in the cache/gui.
+ # CMake requires the docstring parameter whenever set() touches the cache,
+ # so get the existing docstring and re-use that.
+ get_property(flagsvar_docs CACHE ${flagsvar} PROPERTY HELPSTRING)
+ set(${flagsvar} "${${flagsvar}}" CACHE STRING "${flagsvar_docs}" FORCE)
+endmacro(set_flag_in_var)
+
+
+macro(choose_msvc_crt MSVC_CRT)
+ if(LLVM_USE_CRT)
+ message(FATAL_ERROR
+ "LLVM_USE_CRT is deprecated. Use the CMAKE_BUILD_TYPE-specific
+variables (LLVM_USE_CRT_DEBUG, etc) instead.")
+ endif()
+
+ make_crt_regex(MSVC_CRT_REGEX ${MSVC_CRT})
+
+ foreach(build_type ${CMAKE_CONFIGURATION_TYPES})
+ string(TOUPPER "${build_type}" build)
+ if (NOT LLVM_USE_CRT_${build})
+ get_current_crt(LLVM_USE_CRT_${build}
+ MSVC_CRT_REGEX
+ CMAKE_CXX_FLAGS_${build})
+ set(LLVM_USE_CRT_${build}
+ "${LLVM_USE_CRT_${build}}"
+ CACHE STRING "Specify VC++ CRT to use for ${build_type} configurations."
+ FORCE)
+ set_property(CACHE LLVM_USE_CRT_${build}
+ PROPERTY STRINGS "";${${MSVC_CRT}})
+ endif(NOT LLVM_USE_CRT_${build})
+ endforeach(build_type)
+
+ foreach(build_type ${CMAKE_CONFIGURATION_TYPES})
+ string(TOUPPER "${build_type}" build)
+ if ("${LLVM_USE_CRT_${build}}" STREQUAL "")
+ set(flag_string " ")
+ else()
+ set(flag_string " /${LLVM_USE_CRT_${build}} ")
+ list(FIND ${MSVC_CRT} ${LLVM_USE_CRT_${build}} idx)
+ if (idx LESS 0)
+ message(FATAL_ERROR
+ "Invalid value for LLVM_USE_CRT_${build}: ${LLVM_USE_CRT_${build}}. Valid options are one of: ${${MSVC_CRT}}")
+ endif (idx LESS 0)
+ message(STATUS "Using ${build_type} VC++ CRT: ${LLVM_USE_CRT_${build}}")
+ endif()
+ foreach(lang C CXX)
+ set_flag_in_var(CMAKE_${lang}_FLAGS_${build} MSVC_CRT_REGEX flag_string)
+ endforeach(lang)
+ endforeach(build_type)
+endmacro(choose_msvc_crt MSVC_CRT)
+
+
+# List of valid CRTs for MSVC
+set(MSVC_CRT
+ MD
+ MDd
+ MT
+ MTd)
+
+choose_msvc_crt(MSVC_CRT)
+