Modules/TestBigEndian.cmake

   1 # Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
   2 # file Copyright.txt or https://cmake.org/licensing for details.
   3
   4 #[=======================================================================[.rst:
   5 TestBigEndian
   6 -------------
   7
   8 .. deprecated:: 3.20
   9
  10   Supserseded by the :variable:`CMAKE_<LANG>_BYTE_ORDER` variable.
  11
  12 Check if the target architecture is big endian or little endian.
  13
  14 .. command:: test_big_endian
  15
  16   .. code-block:: cmake
  17
  18     test_big_endian(<var>)
  19
  20   Stores in variable ``<var>`` either 1 or 0 indicating whether the
  21   target architecture is big or little endian.
  22
  23 #]=======================================================================]
  24 include_guard()
  25
  26 include(CheckTypeSize)
  27
  28 function(TEST_BIG_ENDIAN VARIABLE)
  29   if(";${CMAKE_C_BYTE_ORDER};${CMAKE_CXX_BYTE_ORDER};${CMAKE_CUDA_BYTE_ORDER};${CMAKE_OBJC_BYTE_ORDER};${CMAKE_OBJCXX_BYTE_ORDER};" MATCHES ";(BIG_ENDIAN|LITTLE_ENDIAN);")
  30     set(order "${CMAKE_MATCH_1}")
  31     if(order STREQUAL "BIG_ENDIAN")
  32       set("${VARIABLE}" 1 PARENT_SCOPE)
  33     else()
  34       set("${VARIABLE}" 0 PARENT_SCOPE)
  35     endif()
  36   else()
  37     __TEST_BIG_ENDIAN_LEGACY_IMPL(is_big)
  38     set("${VARIABLE}" "${is_big}" PARENT_SCOPE)
  39   endif()
  40 endfunction()
  41
  42 macro(__TEST_BIG_ENDIAN_LEGACY_IMPL VARIABLE)
  43   if(NOT DEFINED HAVE_${VARIABLE})
  44     message(CHECK_START "Check if the system is big endian")
  45     message(CHECK_START "Searching 16 bit integer")
  46
  47     if(CMAKE_C_COMPILER_LOADED)
  48       set(_test_language "C")
  49     elseif(CMAKE_CXX_COMPILER_LOADED)
  50       set(_test_language "CXX")
  51     else()
  52       message(FATAL_ERROR "TEST_BIG_ENDIAN needs either C or CXX language enabled")
  53     endif()
  54
  55     CHECK_TYPE_SIZE("unsigned short" CMAKE_SIZEOF_UNSIGNED_SHORT LANGUAGE ${_test_language})
  56     if(CMAKE_SIZEOF_UNSIGNED_SHORT EQUAL 2)
  57       message(CHECK_PASS "Using unsigned short")
  58       set(CMAKE_16BIT_TYPE "unsigned short")
  59     else()
  60       CHECK_TYPE_SIZE("unsigned int"   CMAKE_SIZEOF_UNSIGNED_INT LANGUAGE ${_test_language})
  61       if(CMAKE_SIZEOF_UNSIGNED_INT)
  62         message(CHECK_PASS "Using unsigned int")
  63         set(CMAKE_16BIT_TYPE "unsigned int")
  64
  65       else()
  66
  67         CHECK_TYPE_SIZE("unsigned long"  CMAKE_SIZEOF_UNSIGNED_LONG LANGUAGE ${_test_language})
  68         if(CMAKE_SIZEOF_UNSIGNED_LONG)
  69           message(CHECK_PASS "Using unsigned long")
  70           set(CMAKE_16BIT_TYPE "unsigned long")
  71         else()
  72           message(FATAL_ERROR "no suitable type found")
  73         endif()
  74
  75       endif()
  76
  77     endif()
  78
  79     if(_test_language STREQUAL "CXX")
  80       set(_test_file TestEndianess.cpp)
  81     else()
  82       set(_test_file TestEndianess.c)
  83     endif()
  84
  85     file(READ "${CMAKE_ROOT}/Modules/TestEndianess.c.in" TEST_ENDIANESS_FILE_CONTENT)
  86     string(CONFIGURE "${TEST_ENDIANESS_FILE_CONTENT}" TEST_ENDIANESS_FILE_CONTENT @ONLY)
  87
  88      try_compile(HAVE_${VARIABLE}
  89       SOURCE_FROM_VAR "${_test_file}" TEST_ENDIANESS_FILE_CONTENT
  90       COPY_FILE "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/TestEndianess.bin" )
  91
  92       if(HAVE_${VARIABLE})
  93
  94         cmake_policy(PUSH)
  95         cmake_policy(SET CMP0159 NEW) # file(STRINGS) with REGEX updates CMAKE_MATCH_<n>
  96
  97         file(STRINGS "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/TestEndianess.bin"
  98             CMAKE_TEST_ENDIANESS_STRINGS_LE LIMIT_COUNT 1 REGEX "THIS IS LITTLE ENDIAN")
  99
 100         file(STRINGS "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/TestEndianess.bin"
 101             CMAKE_TEST_ENDIANESS_STRINGS_BE LIMIT_COUNT 1 REGEX "THIS IS BIG ENDIAN")
 102
 103         cmake_policy(POP)
 104
 105         # on mac, if there are universal binaries built both will be true
 106         # return the result depending on the machine on which cmake runs
 107         if(CMAKE_TEST_ENDIANESS_STRINGS_BE  AND  CMAKE_TEST_ENDIANESS_STRINGS_LE)
 108           if(CMAKE_SYSTEM_PROCESSOR MATCHES powerpc)
 109             set(CMAKE_TEST_ENDIANESS_STRINGS_BE TRUE)
 110             set(CMAKE_TEST_ENDIANESS_STRINGS_LE FALSE)
 111           else()
 112             set(CMAKE_TEST_ENDIANESS_STRINGS_BE FALSE)
 113             set(CMAKE_TEST_ENDIANESS_STRINGS_LE TRUE)
 114           endif()
 115           message(STATUS "TEST_BIG_ENDIAN found different results, consider setting CMAKE_OSX_ARCHITECTURES or CMAKE_TRY_COMPILE_OSX_ARCHITECTURES to one or no architecture !")
 116         endif()
 117
 118         if(CMAKE_TEST_ENDIANESS_STRINGS_LE)
 119           set(${VARIABLE} 0 CACHE INTERNAL "Result of TEST_BIG_ENDIAN" FORCE)
 120           message(CHECK_PASS "little endian")
 121         endif()
 122
 123         if(CMAKE_TEST_ENDIANESS_STRINGS_BE)
 124           set(${VARIABLE} 1 CACHE INTERNAL "Result of TEST_BIG_ENDIAN" FORCE)
 125           message(CHECK_PASS "big endian")
 126         endif()
 127
 128         if(NOT CMAKE_TEST_ENDIANESS_STRINGS_BE  AND  NOT CMAKE_TEST_ENDIANESS_STRINGS_LE)
 129           message(CHECK_FAIL "TEST_BIG_ENDIAN found no result!")
 130           message(SEND_ERROR "TEST_BIG_ENDIAN found no result!")
 131         endif()
 132       else()
 133         message(CHECK_FAIL "failed")
 134         set(${VARIABLE})
 135       endif()
 136   endif()
 137 endmacro()