cmake_modules/Platform/Emscripten.cmake
changeset 11663 f87ed83568c8
child 11706 e71435e046a1
equal deleted inserted replaced
11662:ae6706411b24 11663:f87ed83568c8
       
     1 # This file is a 'toolchain description file' for CMake.
       
     2 # It teaches CMake about the Emscripten compiler, so that CMake can generate makefiles
       
     3 # from CMakeLists.txt that invoke emcc.
       
     4 
       
     5 # To use this toolchain file with CMake, invoke CMake with the following command line parameters
       
     6 # cmake -DCMAKE_TOOLCHAIN_FILE=<EmscriptenRoot>/cmake/Modules/Platform/Emscripten.cmake
       
     7 #       -DCMAKE_BUILD_TYPE=<Debug|RelWithDebInfo|Release|MinSizeRel>
       
     8 #       -G "Unix Makefiles" (Linux and OSX)
       
     9 #       -G "MinGW Makefiles" (Windows)
       
    10 #       <path/to/CMakeLists.txt> # Note, pass in here ONLY the path to the file, not the filename 'CMakeLists.txt' itself.
       
    11 
       
    12 # After that, build the generated Makefile with the command 'make'. On Windows, you may download and use 'mingw32-make' instead.
       
    13 
       
    14 # The following variable describes the target OS we are building to.
       
    15 set(CMAKE_SYSTEM_NAME Emscripten)
       
    16 set(CMAKE_SYSTEM_VERSION 1)
       
    17 
       
    18 set(CMAKE_CROSSCOMPILING TRUE)
       
    19 
       
    20 # Advertise Emscripten as a 32-bit platform (as opposed to CMAKE_SYSTEM_PROCESSOR=x86_64 for 64-bit platform),
       
    21 # since some projects (e.g. OpenCV) use this to detect bitness.
       
    22 set(CMAKE_SYSTEM_PROCESSOR x86)
       
    23 
       
    24 # Tell CMake how it should instruct the compiler to generate multiple versions of an outputted .so library: e.g. "libfoo.so, libfoo.so.1, libfoo.so.1.4" etc.
       
    25 # This feature is activated if a shared library project has the property SOVERSION defined.
       
    26 set(CMAKE_SHARED_LIBRARY_SONAME_C_FLAG "-Wl,-soname,")
       
    27 
       
    28 # In CMake, CMAKE_HOST_WIN32 is set when we are cross-compiling from Win32 to Emscripten: http://www.cmake.org/cmake/help/v2.8.12/cmake.html#variable:CMAKE_HOST_WIN32
       
    29 # The variable WIN32 is set only when the target arch that will run the code will be WIN32, so unset WIN32 when cross-compiling.
       
    30 set(WIN32)
       
    31 
       
    32 # The same logic as above applies for APPLE and CMAKE_HOST_APPLE, so unset APPLE.
       
    33 set(APPLE)
       
    34 
       
    35 # And for UNIX and CMAKE_HOST_UNIX. However, Emscripten is often able to mimic being a Linux/Unix system, in which case a lot of existing CMakeLists.txt files can be configured for Emscripten while assuming UNIX build, so this is left enabled.
       
    36 set(UNIX 1)
       
    37 
       
    38 # Do a no-op access on the CMAKE_TOOLCHAIN_FILE variable so that CMake will not issue a warning on it being unused.
       
    39 if(CMAKE_TOOLCHAIN_FILE)
       
    40 endif()
       
    41 
       
    42 # In order for check_function_exists() detection to work, we must signal it to pass an additional flag, which causes the compilation
       
    43 # to abort if linking results in any undefined symbols. The CMake detection mechanism depends on the undefined symbol error to be raised.
       
    44 set(CMAKE_REQUIRED_FLAGS "-s ERROR_ON_UNDEFINED_SYMBOLS=1")
       
    45 
       
    46 # Locate where the Emscripten compiler resides in relative to this toolchain file.
       
    47 if("${EMSCRIPTEN_ROOT_PATH}" STREQUAL "")
       
    48     get_filename_component(GUESS_EMSCRIPTEN_ROOT_PATH "${CMAKE_CURRENT_LIST_DIR}/../../../" ABSOLUTE)
       
    49     if(EXISTS "${GUESS_EMSCRIPTEN_ROOT_PATH}/emranlib")
       
    50         set(EMSCRIPTEN_ROOT_PATH "${GUESS_EMSCRIPTEN_ROOT_PATH}")
       
    51     endif()
       
    52 endif()
       
    53 
       
    54 # If not found by above search, locate using the EMSCRIPTEN environment variable.
       
    55 if("${EMSCRIPTEN_ROOT_PATH}" STREQUAL "")
       
    56     set(EMSCRIPTEN_ROOT_PATH "$ENV{EMSCRIPTEN}")
       
    57 endif()
       
    58 
       
    59 # Abort if not found.
       
    60 if("${EMSCRIPTEN_ROOT_PATH}" STREQUAL "")
       
    61     message(FATAL_ERROR "Could not locate the Emscripten compiler toolchain directory! Either set the EMSCRIPTEN environment variable, or pass -DEMSCRIPTEN_ROOT_PATH=xxx to CMake to explicitly specify the location of the compiler! This usually matches EMSCRIPTEN_ROOT from your ~/.emscripten file.")
       
    62 endif()
       
    63 
       
    64 # Normalize, convert Windows backslashes to forward slashes or CMake will crash.
       
    65 get_filename_component(EMSCRIPTEN_ROOT_PATH "${EMSCRIPTEN_ROOT_PATH}" ABSOLUTE)
       
    66 
       
    67 if(NOT CMAKE_MODULE_PATH)
       
    68     set(CMAKE_MODULE_PATH "")
       
    69 endif()
       
    70 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${EMSCRIPTEN_ROOT_PATH}/cmake/Modules")
       
    71 
       
    72 set(CMAKE_FIND_ROOT_PATH "${EMSCRIPTEN_ROOT_PATH}/system")
       
    73 
       
    74 if(CMAKE_HOST_WIN32)
       
    75     set(EMCC_SUFFIX ".bat")
       
    76 else()
       
    77     set(EMCC_SUFFIX "")
       
    78 endif()
       
    79 
       
    80 # Specify the compilers to use for C and C++
       
    81 if("${CMAKE_C_COMPILER}" STREQUAL "")
       
    82     set(CMAKE_C_COMPILER "${EMSCRIPTEN_ROOT_PATH}/emcc${EMCC_SUFFIX}")
       
    83 endif()
       
    84 if("${CMAKE_CXX_COMPILER}" STREQUAL "")
       
    85     set(CMAKE_CXX_COMPILER "${EMSCRIPTEN_ROOT_PATH}/em++${EMCC_SUFFIX}")
       
    86 endif()
       
    87 
       
    88 if("${CMAKE_AR}" STREQUAL "")
       
    89     set(CMAKE_AR "${EMSCRIPTEN_ROOT_PATH}/emar${EMCC_SUFFIX}" CACHE FILEPATH "Emscripten ar")
       
    90 endif()
       
    91 
       
    92 if("${CMAKE_RANLIB}" STREQUAL "")
       
    93     set(CMAKE_RANLIB "${EMSCRIPTEN_ROOT_PATH}/emranlib${EMCC_SUFFIX}" CACHE FILEPATH "Emscripten ranlib")
       
    94 endif()
       
    95 
       
    96 # Don't do compiler autodetection, since we are cross-compiling.
       
    97 include(CMakeForceCompiler)
       
    98 CMAKE_FORCE_C_COMPILER("${CMAKE_C_COMPILER}" Clang)
       
    99 CMAKE_FORCE_CXX_COMPILER("${CMAKE_CXX_COMPILER}" Clang)
       
   100 
       
   101 # To find programs to execute during CMake run time with find_program(), e.g. 'git' or so, we allow looking
       
   102 # into system paths.
       
   103 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
       
   104 
       
   105 # Since Emscripten is a cross-compiler, we should never look at the system-provided directories like /usr/include and so on.
       
   106 # Therefore only CMAKE_FIND_ROOT_PATH should be used as a find directory. See http://www.cmake.org/cmake/help/v3.0/variable/CMAKE_FIND_ROOT_PATH_MODE_INCLUDE.html
       
   107 set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
       
   108 set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
       
   109 set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
       
   110 
       
   111 set(CMAKE_SYSTEM_INCLUDE_PATH "${EMSCRIPTEN_ROOT_PATH}/system/include")
       
   112 
       
   113 # We would prefer to specify a standard set of Clang+Emscripten-friendly common convention for suffix files, especially for CMake executable files,
       
   114 # but if these are adjusted, ${CMAKE_ROOT}/Modules/CheckIncludeFile.cmake will fail, since it depends on being able to compile output files with predefined names.
       
   115 #SET(CMAKE_LINK_LIBRARY_SUFFIX "")
       
   116 #SET(CMAKE_STATIC_LIBRARY_PREFIX "")
       
   117 #SET(CMAKE_STATIC_LIBRARY_SUFFIX ".bc")
       
   118 #SET(CMAKE_SHARED_LIBRARY_PREFIX "")
       
   119 #SET(CMAKE_SHARED_LIBRARY_SUFFIX ".bc")
       
   120 SET(CMAKE_EXECUTABLE_SUFFIX ".js")
       
   121 #SET(CMAKE_FIND_LIBRARY_PREFIXES "")
       
   122 #SET(CMAKE_FIND_LIBRARY_SUFFIXES ".bc")
       
   123 
       
   124 SET(CMAKE_C_USE_RESPONSE_FILE_FOR_LIBRARIES 1)
       
   125 SET(CMAKE_CXX_USE_RESPONSE_FILE_FOR_LIBRARIES 1)
       
   126 SET(CMAKE_C_USE_RESPONSE_FILE_FOR_OBJECTS 1)
       
   127 SET(CMAKE_CXX_USE_RESPONSE_FILE_FOR_OBJECTS 1)
       
   128 SET(CMAKE_C_USE_RESPONSE_FILE_FOR_INCLUDES 1)
       
   129 SET(CMAKE_CXX_USE_RESPONSE_FILE_FOR_INCLUDES 1)
       
   130 
       
   131 set(CMAKE_C_RESPONSE_FILE_LINK_FLAG "@")
       
   132 set(CMAKE_CXX_RESPONSE_FILE_LINK_FLAG "@")
       
   133 
       
   134 # Specify the program to use when building static libraries. Force Emscripten-related command line options to clang.
       
   135 set(CMAKE_C_CREATE_STATIC_LIBRARY "<CMAKE_AR> rc <TARGET> <LINK_FLAGS> <OBJECTS>")
       
   136 set(CMAKE_CXX_CREATE_STATIC_LIBRARY "<CMAKE_AR> rc <TARGET> <LINK_FLAGS> <OBJECTS>")
       
   137 
       
   138 # Set a global EMSCRIPTEN variable that can be used in client CMakeLists.txt to detect when building using Emscripten.
       
   139 set(EMSCRIPTEN 1 CACHE BOOL "If true, we are targeting Emscripten output.")
       
   140 
       
   141 # Hardwire support for cmake-2.8/Modules/CMakeBackwardsCompatibilityC.cmake without having CMake to try complex things
       
   142 # to autodetect these:
       
   143 set(CMAKE_SKIP_COMPATIBILITY_TESTS 1)
       
   144 set(CMAKE_SIZEOF_CHAR 1)
       
   145 set(CMAKE_SIZEOF_UNSIGNED_SHORT 2)
       
   146 set(CMAKE_SIZEOF_SHORT 2)
       
   147 set(CMAKE_SIZEOF_INT 4)
       
   148 set(CMAKE_SIZEOF_UNSIGNED_LONG 4)
       
   149 set(CMAKE_SIZEOF_UNSIGNED_INT 4)
       
   150 set(CMAKE_SIZEOF_LONG 4)
       
   151 set(CMAKE_SIZEOF_VOID_P 4)
       
   152 set(CMAKE_SIZEOF_FLOAT 4)
       
   153 set(CMAKE_SIZEOF_DOUBLE 8)
       
   154 set(CMAKE_C_SIZEOF_DATA_PTR 4)
       
   155 set(CMAKE_CXX_SIZEOF_DATA_PTR 4)
       
   156 set(CMAKE_HAVE_LIMITS_H 1)
       
   157 set(CMAKE_HAVE_UNISTD_H 1)
       
   158 set(CMAKE_HAVE_PTHREAD_H 1)
       
   159 set(CMAKE_HAVE_SYS_PRCTL_H 1)
       
   160 set(CMAKE_WORDS_BIGENDIAN 0)
       
   161 set(CMAKE_DL_LIBS)
       
   162 
       
   163 set(CMAKE_C_FLAGS_RELEASE "-DNDEBUG -O2" CACHE STRING "Emscripten-overridden CMAKE_C_FLAGS_RELEASE")
       
   164 set(CMAKE_C_FLAGS_MINSIZEREL "-DNDEBUG -Os" CACHE STRING "Emscripten-overridden CMAKE_C_FLAGS_MINSIZEREL")
       
   165 set(CMAKE_C_FLAGS_RELWITHDEBINFO "-O2" CACHE STRING "Emscripten-overridden CMAKE_C_FLAGS_RELWITHDEBINFO")
       
   166 set(CMAKE_CXX_FLAGS_RELEASE "-DNDEBUG -O2" CACHE STRING "Emscripten-overridden CMAKE_CXX_FLAGS_RELEASE")
       
   167 set(CMAKE_CXX_FLAGS_MINSIZEREL "-DNDEBUG -Os" CACHE STRING "Emscripten-overridden CMAKE_CXX_FLAGS_MINSIZEREL")
       
   168 set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O2" CACHE STRING "Emscripten-overridden CMAKE_CXX_FLAGS_RELWITHDEBINFO")
       
   169 
       
   170 set(CMAKE_EXE_LINKER_FLAGS_RELEASE "-O2" CACHE STRING "Emscripten-overridden CMAKE_EXE_LINKER_FLAGS_RELEASE")
       
   171 set(CMAKE_EXE_LINKER_FLAGS_MINSIZEREL "-Os" CACHE STRING "Emscripten-overridden CMAKE_EXE_LINKER_FLAGS_MINSIZEREL")
       
   172 set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "-O2 -g" CACHE STRING "Emscripten-overridden CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO")
       
   173 set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "-O2" CACHE STRING "Emscripten-overridden CMAKE_SHARED_LINKER_FLAGS_RELEASE")
       
   174 set(CMAKE_SHARED_LINKER_FLAGS_MINSIZEREL "-Os" CACHE STRING "Emscripten-overridden CMAKE_SHARED_LINKER_FLAGS_MINSIZEREL")
       
   175 set(CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO "-O2 -g" CACHE STRING "Emscripten-overridden CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO")
       
   176 set(CMAKE_MODULE_LINKER_FLAGS_RELEASE "-O2" CACHE STRING "Emscripten-overridden CMAKE_MODULE_LINKER_FLAGS_RELEASE")
       
   177 set(CMAKE_MODULE_LINKER_FLAGS_MINSIZEREL "-Os" CACHE STRING "Emscripten-overridden CMAKE_MODULE_LINKER_FLAGS_MINSIZEREL")
       
   178 set(CMAKE_MODULE_LINKER_FLAGS_RELWITHDEBINFO "-O2 -g" CACHE STRING "Emscripten-overridden CMAKE_MODULE_LINKER_FLAGS_RELWITHDEBINFO")
       
   179 
       
   180 function(em_validate_asmjs_after_build target)
       
   181     add_custom_command(TARGET ${target} POST_BUILD COMMAND ${CMAKE_COMMAND} -E echo Validating build output for asm.js... COMMAND "python" ARGS "${EMSCRIPTEN_ROOT_PATH}/tools/validate_asmjs.py" "$<TARGET_FILE:${target}>")
       
   182 endfunction()
       
   183 
       
   184 # A global counter to guarantee unique names for js library files.
       
   185 set(link_js_counter 1)
       
   186 
       
   187 # Internal function: Do not call from user CMakeLists.txt files. Use one of em_link_js_library()/em_link_pre_js()/em_link_post_js() instead.
       
   188 function(em_add_tracked_link_flag target flagname)
       
   189 
       
   190     # User can input list of JS files either as a single list, or as variable arguments to this function, so iterate over varargs, and treat each
       
   191     # item in varargs as a list itself, to support both syntax forms.
       
   192     foreach(jsFileList ${ARGN})
       
   193         foreach(jsfile ${jsFileList})
       
   194             # If the user edits the JS file, we want to relink the emscripten application, but unfortunately it is not possible to make a link step
       
   195             # depend directly on a source file. Instead, we must make a dummy no-op build target on that source file, and make the project depend on
       
   196             # that target.
       
   197 
       
   198             # Sanitate the source .js filename to a good symbol name to use as a dummy filename.
       
   199             get_filename_component(jsname "${jsfile}" NAME)
       
   200             string(REGEX REPLACE "[/:\\\\.\ ]" "_" dummy_js_target ${jsname})
       
   201             set(dummy_lib_name ${target}_${link_js_counter}_${dummy_js_target})
       
   202             set(dummy_c_name "${CMAKE_BINARY_DIR}/${dummy_js_target}_tracker.c")
       
   203 
       
   204             # Create a new static library target that with a single dummy .c file.
       
   205             add_library(${dummy_lib_name} STATIC ${dummy_c_name})
       
   206             # Make the dummy .c file depend on the .js file we are linking, so that if the .js file is edited, the dummy .c file, and hence the static library will be rebuild (no-op). This causes the main application to be relinked, which is what we want.
       
   207             # This approach was recommended by http://www.cmake.org/pipermail/cmake/2010-May/037206.html
       
   208             add_custom_command(OUTPUT ${dummy_c_name} COMMAND ${CMAKE_COMMAND} -E touch ${dummy_c_name} DEPENDS ${jsfile})
       
   209             target_link_libraries(${target} ${dummy_lib_name})
       
   210 
       
   211             # Link the js-library to the target
       
   212             # When a linked library starts with a "-" cmake will just add it to the linker command line as it is.
       
   213             # The advantage of doing it this way is that the js-library will also be automatically linked to targets
       
   214             # that depend on this target.
       
   215             get_filename_component(js_file_absolute_path "${jsfile}" ABSOLUTE )
       
   216             target_link_libraries(${target} "${flagname} \"${js_file_absolute_path}\"")
       
   217 
       
   218             math(EXPR link_js_counter "${link_js_counter} + 1")
       
   219         endforeach()
       
   220     endforeach()
       
   221 endfunction()
       
   222 
       
   223 # This function links a (list of ) .js library file(s) to the given CMake project.
       
   224 # Example: em_link_js_library(my_executable "lib1.js" "lib2.js")
       
   225 #    will result in emcc passing --js-library lib1.js --js-library lib2.js to the emscripten linker, as well as
       
   226 #    tracking the modification timestamp between the linked .js files and the main project, so that editing the .js file
       
   227 #    will cause the target project to be relinked.
       
   228 function(em_link_js_library target)
       
   229     em_add_tracked_link_flag(${target} "--js-library" ${ARGN})
       
   230 endfunction()
       
   231 
       
   232 # This function is identical to em_link_js_library(), except the .js files will be added with '--pre-js file.js' command line flag,
       
   233 # which is generally used to add some preamble .js code to a generated output file.
       
   234 function(em_link_pre_js target)
       
   235     em_add_tracked_link_flag(${target} "--pre-js" ${ARGN})
       
   236 endfunction()
       
   237 
       
   238 # This function is identical to em_link_js_library(), except the .js files will be added with '--post-js file.js' command line flag,
       
   239 # which is generally used to add some postamble .js code to a generated output file.
       
   240 function(em_link_post_js target)
       
   241     em_add_tracked_link_flag(${target} "--post-js" ${ARGN})
       
   242 endfunction()
       
   243 
       
   244 # Experimental support for targeting generation of Visual Studio project files (vs-tool) of Emscripten projects for Windows.
       
   245 # To use this, pass the combination -G "Visual Studio 10" -DCMAKE_TOOLCHAIN_FILE=Emscripten.cmake
       
   246 if ("${CMAKE_GENERATOR}" MATCHES "^Visual Studio.*")
       
   247     # By default, CMake generates VS project files with a <GenerateManifest>true</GenerateManifest> directive.
       
   248     # This causes VS to attempt to invoke rc.exe during the build, which will fail since app manifests are meaningless for Emscripten.
       
   249     # To disable this, add the following linker flag. This flag will not go to emcc, since the Visual Studio CMake generator will swallow it.
       
   250     set(EMSCRIPTEN_VS_LINKER_FLAGS "/MANIFEST:NO")
       
   251     # CMake is hardcoded to write a ClCompile directive <ObjectFileName>$(IntDir)</ObjectFileName> in all VS project files it generates.
       
   252     # This makes VS pass emcc a -o param that points to a directory instead of a file, which causes emcc autogenerate the output filename.
       
   253     # CMake is hardcoded to assume all object files have the suffix .obj, so adjust the emcc-autogenerated default suffix name to match.
       
   254     set(EMSCRIPTEN_VS_LINKER_FLAGS "${EMSCRIPTEN_VS_LINKER_FLAGS} --default-obj-ext .obj")
       
   255     # Also hint CMake that it should not hardcode <ObjectFileName> generation. Requires a custom CMake build for this to work (ignored on others)
       
   256     # See http://www.cmake.org/Bug/view.php?id=14673 and https://github.com/juj/CMake
       
   257     set(CMAKE_VS_NO_DEFAULT_OBJECTFILENAME 1)
       
   258 
       
   259     # Apply and cache Emscripten Visual Studio IDE-specific linker flags.
       
   260     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${EMSCRIPTEN_VS_LINKER_FLAGS}" CACHE STRING "")
       
   261     set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${EMSCRIPTEN_VS_LINKER_FLAGS}" CACHE STRING "")
       
   262     set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${EMSCRIPTEN_VS_LINKER_FLAGS}" CACHE STRING "")
       
   263 endif()
       
   264 
       
   265 if(NOT DEFINED CMAKE_CROSSCOMPILING_EMULATOR)
       
   266   find_program(NODE_JS_EXECUTABLE NAMES nodejs node)
       
   267   if(NODE_JS_EXECUTABLE)
       
   268     set(CMAKE_CROSSCOMPILING_EMULATOR "${NODE_JS_EXECUTABLE}" CACHE FILEPATH "Path to the emulator for the target system.")
       
   269   endif()
       
   270 endif()
       
   271 
       
   272 # No-op on CMAKE_CROSSCOMPILING_EMULATOR so older versions of cmake do not
       
   273 # complain about unused CMake variable.
       
   274 if(CMAKE_CROSSCOMPILING_EMULATOR)
       
   275 endif()