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      1 # The macro choose_msvc_crt() takes a list of possible
      2 # C runtimes to choose from, in the form of compiler flags,
      3 # to present to the user. (MTd for /MTd, etc)
      4 #
      5 # The macro is invoked at the end of the file.
      6 #
      7 # CMake already sets CRT flags in the CMAKE_CXX_FLAGS_* and
      8 # CMAKE_C_FLAGS_* variables by default. To let the user
      9 # override that for each build type:
     10 # 1. Detect which CRT is already selected, and reflect this in
     11 # LLVM_USE_CRT_* so the user can have a better idea of what
     12 # changes they're making.
     13 # 2. Replace the flags in both variables with the new flag via a regex.
     14 # 3. set() the variables back into the cache so the changes
     15 # are user-visible.
     16 
     17 ### Helper macros: ###
     18 macro(make_crt_regex regex crts)
     19   set(${regex} "")
     20   foreach(crt ${${crts}})
     21     # Trying to match the beginning or end of the string with stuff
     22     # like [ ^]+ didn't work, so use a bunch of parentheses instead.
     23     set(${regex} "${${regex}}|(^| +)/${crt}($| +)")
     24   endforeach(crt)
     25   string(REGEX REPLACE "^\\|" "" ${regex} "${${regex}}")
     26 endmacro(make_crt_regex)
     27 
     28 macro(get_current_crt crt_current regex flagsvar)
     29   # Find the selected-by-CMake CRT for each build type, if any.
     30   # Strip off the leading slash and any whitespace.
     31   string(REGEX MATCH "${${regex}}" ${crt_current} "${${flagsvar}}")
     32   string(REPLACE "/" " " ${crt_current} "${${crt_current}}")
     33   string(STRIP "${${crt_current}}" ${crt_current})
     34 endmacro(get_current_crt)
     35 
     36 # Replaces or adds a flag to a variable.
     37 # Expects 'flag' to be padded with spaces.
     38 macro(set_flag_in_var flagsvar regex flag)
     39   string(REGEX MATCH "${${regex}}" current_flag "${${flagsvar}}")
     40   if("${current_flag}" STREQUAL "")
     41     set(${flagsvar} "${${flagsvar}}${${flag}}")
     42   else()
     43     string(REGEX REPLACE "${${regex}}" "${${flag}}" ${flagsvar} "${${flagsvar}}")
     44   endif()
     45   string(STRIP "${${flagsvar}}" ${flagsvar})
     46   # Make sure this change gets reflected in the cache/gui.
     47   # CMake requires the docstring parameter whenever set() touches the cache,
     48   # so get the existing docstring and re-use that.
     49   get_property(flagsvar_docs CACHE ${flagsvar} PROPERTY HELPSTRING)
     50   set(${flagsvar} "${${flagsvar}}" CACHE STRING "${flagsvar_docs}" FORCE)
     51 endmacro(set_flag_in_var)
     52 
     53 
     54 macro(choose_msvc_crt MSVC_CRT)
     55   if(LLVM_USE_CRT)
     56     message(FATAL_ERROR
     57       "LLVM_USE_CRT is deprecated. Use the CMAKE_BUILD_TYPE-specific
     58 variables (LLVM_USE_CRT_DEBUG, etc) instead.")
     59   endif()
     60 
     61   make_crt_regex(MSVC_CRT_REGEX ${MSVC_CRT})
     62 
     63   foreach(build_type ${CMAKE_CONFIGURATION_TYPES} ${CMAKE_BUILD_TYPE})
     64     string(TOUPPER "${build_type}" build)
     65     if (NOT LLVM_USE_CRT_${build})
     66       get_current_crt(LLVM_USE_CRT_${build}
     67         MSVC_CRT_REGEX
     68         CMAKE_CXX_FLAGS_${build})
     69       set(LLVM_USE_CRT_${build}
     70         "${LLVM_USE_CRT_${build}}"
     71         CACHE STRING "Specify VC++ CRT to use for ${build_type} configurations."
     72         FORCE)
     73       set_property(CACHE LLVM_USE_CRT_${build}
     74         PROPERTY STRINGS ;${${MSVC_CRT}})
     75     endif(NOT LLVM_USE_CRT_${build})
     76   endforeach(build_type)
     77 
     78   foreach(build_type ${CMAKE_CONFIGURATION_TYPES} ${CMAKE_BUILD_TYPE})
     79     string(TOUPPER "${build_type}" build)
     80     if ("${LLVM_USE_CRT_${build}}" STREQUAL "")
     81       set(flag_string " ")
     82     else()
     83       set(flag_string " /${LLVM_USE_CRT_${build}} ")
     84       list(FIND ${MSVC_CRT} ${LLVM_USE_CRT_${build}} idx)
     85       if (idx LESS 0)
     86         message(FATAL_ERROR
     87           "Invalid value for LLVM_USE_CRT_${build}: ${LLVM_USE_CRT_${build}}. Valid options are one of: ${${MSVC_CRT}}")
     88       endif (idx LESS 0)
     89       message(STATUS "Using ${build_type} VC++ CRT: ${LLVM_USE_CRT_${build}}")
     90     endif()
     91     foreach(lang C CXX)
     92       set_flag_in_var(CMAKE_${lang}_FLAGS_${build} MSVC_CRT_REGEX flag_string)
     93     endforeach(lang)
     94   endforeach(build_type)
     95 endmacro(choose_msvc_crt MSVC_CRT)
     96 
     97 
     98 # List of valid CRTs for MSVC
     99 set(MSVC_CRT
    100   MD
    101   MDd
    102   MT
    103   MTd)
    104 
    105 choose_msvc_crt(MSVC_CRT)
    106 
    107