1include(CMakeCheckCompilerFlagCommonPatterns)
2
3# Test compiler can compile simple C/C++/Objective-C program without invoking
4# the linker.
5#
6# try_compile_only(
7#   OUTPUT_VAR
8#   [SOURCE source_text]
9#   [FLAGS flag_0 [ flag_1 ]]
10# )
11#
12# OUTPUT_VAR - The variable name to store the result. The result is a boolean
13#              `True` or `False`.
14#
15# SOURCE     - Optional. If specified use source the source text string
16#              specified. If not specified source code will be used that is C,
17#              C++, and Objective-C compatible.
18#
19# FLAGS      - Optional. If specified pass the one or more specified flags to
20#              the compiler.
21#
22# EXAMPLES:
23#
24# try_compile_only(HAS_F_NO_RTTI FLAGS "-fno-rtti")
25#
26# try_compile_only(HAS_CXX_AUTO_TYPE_DECL
27#   SOURCE "int foo(int x) { auto y = x + 1; return y;}"
28#   FLAGS "-x" "c++" "-std=c++11" "-Werror=c++11-extensions"
29# )
30#
31function(try_compile_only output)
32  # NOTE: `SOURCE` needs to be a multi-argument because source code
33  # often contains semicolons which happens to be CMake's list separator
34  # which confuses `cmake_parse_arguments()`.
35  cmake_parse_arguments(ARG "" "" "SOURCE;FLAGS" ${ARGN})
36  if (ARG_UNPARSED_ARGUMENTS)
37    message(FATAL_ERROR "Unexpected arguments \"${ARG_UNPARSED_ARGUMENTS}\"")
38  endif()
39  if(NOT ARG_SOURCE)
40    set(ARG_SOURCE "int foo(int x, int y) { return x + y; }\n")
41  endif()
42  set(SIMPLE_C ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/src.c)
43  file(WRITE ${SIMPLE_C} "${ARG_SOURCE}\n")
44  string(REGEX MATCHALL "<[A-Za-z0-9_]*>" substitutions
45         ${CMAKE_C_COMPILE_OBJECT})
46
47  set(TRY_COMPILE_FLAGS "${ARG_FLAGS}")
48  if(CMAKE_C_COMPILER_ID MATCHES Clang AND CMAKE_C_COMPILER_TARGET)
49    list(APPEND TRY_COMPILE_FLAGS "-target ${CMAKE_C_COMPILER_TARGET}")
50  endif()
51
52  string(REPLACE ";" " " extra_flags "${TRY_COMPILE_FLAGS}")
53
54  set(test_compile_command "${CMAKE_C_COMPILE_OBJECT}")
55  foreach(substitution ${substitutions})
56    if(substitution STREQUAL "<CMAKE_C_COMPILER>")
57      string(REPLACE "<CMAKE_C_COMPILER>"
58             "${CMAKE_C_COMPILER}" test_compile_command ${test_compile_command})
59    elseif(substitution STREQUAL "<OBJECT>")
60      string(REPLACE "<OBJECT>"
61             "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/test.o"
62             test_compile_command ${test_compile_command})
63    elseif(substitution STREQUAL "<SOURCE>")
64      string(REPLACE "<SOURCE>" "${SIMPLE_C}" test_compile_command
65             ${test_compile_command})
66    elseif(substitution STREQUAL "<FLAGS>")
67      string(REPLACE "<FLAGS>" "${CMAKE_C_FLAGS} ${extra_flags}"
68             test_compile_command ${test_compile_command})
69    else()
70      string(REPLACE "${substitution}" "" test_compile_command
71             ${test_compile_command})
72    endif()
73  endforeach()
74
75  # Strip quotes from the compile command, as the compiler is not expecting
76  # quoted arguments (see discussion on D62063 for when this can come up). If
77  # the quotes were there for arugments with spaces in them, the quotes were
78  # not going to help since the string gets split on spaces below.
79  string(REPLACE "\"" "" test_compile_command "${test_compile_command}")
80
81  string(REPLACE " " ";" test_compile_command "${test_compile_command}")
82
83  execute_process(
84    COMMAND ${test_compile_command}
85    RESULT_VARIABLE result
86    OUTPUT_VARIABLE TEST_OUTPUT
87    ERROR_VARIABLE TEST_ERROR
88  )
89
90  CHECK_COMPILER_FLAG_COMMON_PATTERNS(_CheckCCompilerFlag_COMMON_PATTERNS)
91  set(ERRORS_FOUND OFF)
92  foreach(var ${_CheckCCompilerFlag_COMMON_PATTERNS})
93    if("${var}" STREQUAL "FAIL_REGEX")
94      continue()
95    endif()
96    if("${TEST_ERROR}" MATCHES "${var}" OR "${TEST_OUTPUT}" MATCHES "${var}")
97      set(ERRORS_FOUND ON)
98    endif()
99  endforeach()
100
101  if(result EQUAL 0 AND NOT ERRORS_FOUND)
102    set(${output} True PARENT_SCOPE)
103  else()
104    file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
105        "Testing compiler for supporting " ${ARGN} ":\n"
106        "Command: ${test_compile_command}\n"
107        "${TEST_OUTPUT}\n${TEST_ERROR}\n${result}\n")
108    set(${output} False PARENT_SCOPE)
109  endif()
110endfunction()
111
112function(builtin_check_c_compiler_flag flag output)
113  if(NOT DEFINED ${output})
114    message(STATUS "Performing Test ${output}")
115    try_compile_only(result FLAGS ${flag})
116    set(${output} ${result} CACHE INTERNAL "Compiler supports ${flag}")
117    if(${result})
118      message(STATUS "Performing Test ${output} - Success")
119    else()
120      message(STATUS "Performing Test ${output} - Failed")
121    endif()
122  endif()
123endfunction()
124
125function(builtin_check_c_compiler_source output source)
126  if(NOT DEFINED ${output})
127    message(STATUS "Performing Test ${output}")
128    try_compile_only(result SOURCE ${source})
129    set(${output} ${result} CACHE INTERNAL "Compiler supports ${flag}")
130    if(${result})
131      message(STATUS "Performing Test ${output} - Success")
132    else()
133      message(STATUS "Performing Test ${output} - Failed")
134    endif()
135  endif()
136endfunction()
137