1# Copyright (C) 2020 The Khronos Group Inc.
2#
3# All rights reserved.
4#
5# Redistribution and use in source and binary forms, with or without
6# modification, are permitted provided that the following conditions
7# are met:
8#
9#    Redistributions of source code must retain the above copyright
10#    notice, this list of conditions and the following disclaimer.
11#
12#    Redistributions in binary form must reproduce the above
13#    copyright notice, this list of conditions and the following
14#    disclaimer in the documentation and/or other materials provided
15#    with the distribution.
16#
17#    Neither the name of The Khronos Group Inc. nor the names of its
18#    contributors may be used to endorse or promote products derived
19#    from this software without specific prior written permission.
20#
21# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25# COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
27# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
29# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
31# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32# POSSIBILITY OF SUCH DAMAGE.
33
34# The macro choose_msvc_crt() takes a list of possible
35# C runtimes to choose from, in the form of compiler flags,
36# to present to the user. (MTd for /MTd, etc)
37#
38# The macro is invoked at the end of the file.
39#
40# CMake already sets CRT flags in the CMAKE_CXX_FLAGS_* and
41# CMAKE_C_FLAGS_* variables by default. To let the user
42# override that for each build type:
43# 1. Detect which CRT is already selected, and reflect this in
44# LLVM_USE_CRT_* so the user can have a better idea of what
45# changes they're making.
46# 2. Replace the flags in both variables with the new flag via a regex.
47# 3. set() the variables back into the cache so the changes
48# are user-visible.
49
50### Helper macros: ###
51macro(make_crt_regex regex crts)
52  set(${regex} "")
53  foreach(crt ${${crts}})
54    # Trying to match the beginning or end of the string with stuff
55    # like [ ^]+ didn't work, so use a bunch of parentheses instead.
56    set(${regex} "${${regex}}|(^| +)/${crt}($| +)")
57  endforeach(crt)
58  string(REGEX REPLACE "^\\|" "" ${regex} "${${regex}}")
59endmacro(make_crt_regex)
60
61macro(get_current_crt crt_current regex flagsvar)
62  # Find the selected-by-CMake CRT for each build type, if any.
63  # Strip off the leading slash and any whitespace.
64  string(REGEX MATCH "${${regex}}" ${crt_current} "${${flagsvar}}")
65  string(REPLACE "/" " " ${crt_current} "${${crt_current}}")
66  string(STRIP "${${crt_current}}" ${crt_current})
67endmacro(get_current_crt)
68
69# Replaces or adds a flag to a variable.
70# Expects 'flag' to be padded with spaces.
71macro(set_flag_in_var flagsvar regex flag)
72  string(REGEX MATCH "${${regex}}" current_flag "${${flagsvar}}")
73  if("${current_flag}" STREQUAL "")
74    set(${flagsvar} "${${flagsvar}}${${flag}}")
75  else()
76    string(REGEX REPLACE "${${regex}}" "${${flag}}" ${flagsvar} "${${flagsvar}}")
77  endif()
78  string(STRIP "${${flagsvar}}" ${flagsvar})
79  # Make sure this change gets reflected in the cache/gui.
80  # CMake requires the docstring parameter whenever set() touches the cache,
81  # so get the existing docstring and re-use that.
82  get_property(flagsvar_docs CACHE ${flagsvar} PROPERTY HELPSTRING)
83  set(${flagsvar} "${${flagsvar}}" CACHE STRING "${flagsvar_docs}" FORCE)
84endmacro(set_flag_in_var)
85
86
87macro(choose_msvc_crt MSVC_CRT)
88  if(LLVM_USE_CRT)
89    message(FATAL_ERROR
90      "LLVM_USE_CRT is deprecated. Use the CMAKE_BUILD_TYPE-specific
91variables (LLVM_USE_CRT_DEBUG, etc) instead.")
92  endif()
93
94  make_crt_regex(MSVC_CRT_REGEX ${MSVC_CRT})
95
96  foreach(build_type ${CMAKE_CONFIGURATION_TYPES} ${CMAKE_BUILD_TYPE})
97    string(TOUPPER "${build_type}" build)
98    if (NOT LLVM_USE_CRT_${build})
99      get_current_crt(LLVM_USE_CRT_${build}
100        MSVC_CRT_REGEX
101        CMAKE_CXX_FLAGS_${build})
102      set(LLVM_USE_CRT_${build}
103        "${LLVM_USE_CRT_${build}}"
104        CACHE STRING "Specify VC++ CRT to use for ${build_type} configurations."
105        FORCE)
106      set_property(CACHE LLVM_USE_CRT_${build}
107        PROPERTY STRINGS ;${${MSVC_CRT}})
108    endif(NOT LLVM_USE_CRT_${build})
109  endforeach(build_type)
110
111  foreach(build_type ${CMAKE_CONFIGURATION_TYPES} ${CMAKE_BUILD_TYPE})
112    string(TOUPPER "${build_type}" build)
113    if ("${LLVM_USE_CRT_${build}}" STREQUAL "")
114      set(flag_string " ")
115    else()
116      set(flag_string " /${LLVM_USE_CRT_${build}} ")
117      list(FIND ${MSVC_CRT} ${LLVM_USE_CRT_${build}} idx)
118      if (idx LESS 0)
119        message(FATAL_ERROR
120          "Invalid value for LLVM_USE_CRT_${build}: ${LLVM_USE_CRT_${build}}. Valid options are one of: ${${MSVC_CRT}}")
121      endif (idx LESS 0)
122      message(STATUS "Using ${build_type} VC++ CRT: ${LLVM_USE_CRT_${build}}")
123    endif()
124    foreach(lang C CXX)
125      set_flag_in_var(CMAKE_${lang}_FLAGS_${build} MSVC_CRT_REGEX flag_string)
126    endforeach(lang)
127  endforeach(build_type)
128endmacro(choose_msvc_crt MSVC_CRT)
129
130
131# List of valid CRTs for MSVC
132set(MSVC_CRT
133  MD
134  MDd
135  MT
136  MTd)
137
138choose_msvc_crt(MSVC_CRT)
139