Merge pull request #1583 from juj/cmake_improvements

Cmake improvements

2 files changed, 91 insertions, 39 deletions

diff --git a/cmake/Platform/Emscripten.cmake b/cmake/Platform/Emscripten.cmake
index aafd38a8..9bfa829d 100644
--- a/cmake/Platform/Emscripten.cmake
+++ b/cmake/Platform/Emscripten.cmake
@@ -1,48 +1,124 @@
 # This file is a 'toolchain description file' for CMake.
-# It teaches CMake about the Emscripten compiler, so that CMake can generate Unix Makefiles
+# It teaches CMake about the Emscripten compiler, so that CMake can generate makefiles
 # from CMakeLists.txt that invoke emcc.
 
 # To use this toolchain file with CMake, invoke CMake with the following command line parameters
-# cmake -DEMSCRIPTEN=1 
-#       -DCMAKE_TOOLCHAIN_FILE=<EmscriptenRoot>/cmake/Platform/Emscripten.cmake
-#       -DCMAKE_MODULE_PATH=<EmscriptenRoot>/cmake
+# cmake -DCMAKE_TOOLCHAIN_FILE=<EmscriptenRoot>/cmake/Platform/Emscripten.cmake
 #       -DCMAKE_BUILD_TYPE=<Debug|RelWithDebInfo|Release|MinSizeRel>
-#       -G "Unix Makefiles"
+#       -G "Unix Makefiles" (Linux and OSX)
+#       -G "MinGW Makefiles" (Windows)
 #       <path/to/CMakeLists.txt> # Note, pass in here ONLY the path to the file, not the filename 'CMakeLists.txt' itself.
 
 # After that, build the generated Makefile with the command 'make'. On Windows, you may download and use 'mingw32-make' instead.
 
-# the name of the target operating system
-set(CMAKE_SYSTEM_NAME Emscripten)
+# The following variable describes the target OS we are building to.
+# Ideally, this could be 'Emscripten', but as Emscripten mimics the Linux platform, setting this to Linux will allow more of existing software to build.
+# Be sure to run Emscripten test_openjpeg if planning to change this.
+set(CMAKE_SYSTEM_NAME Linux)
 set(CMAKE_SYSTEM_VERSION 1)
 
+set(CMAKE_CROSSCOMPILING TRUE)
+
+# Do a no-op access on the CMAKE_TOOLCHAIN_FILE variable so that CMake will not issue a warning on it being unused.
+if (CMAKE_TOOLCHAIN_FILE)
+endif()
+
+# Locate where the Emscripten compiler resides in relative to this toolchain file.
 if ("${EMSCRIPTEN_ROOT_PATH}" STREQUAL "")
-	set(CMAKE_FIND_ROOT_PATH "$ENV{EMSCRIPTEN}")
+	get_filename_component(GUESS_EMSCRIPTEN_ROOT_PATH "${CMAKE_CURRENT_LIST_DIR}/../../" ABSOLUTE)
+	if (EXISTS "${GUESS_EMSCRIPTEN_ROOT_PATH}/emranlib")
+		set(EMSCRIPTEN_ROOT_PATH "${GUESS_EMSCRIPTEN_ROOT_PATH}")
+	endif()
+endif()
+
+# If not found by above search, locate using the EMSCRIPTEN environment variable.
+if ("${EMSCRIPTEN_ROOT_PATH}" STREQUAL "")
+	set(EMSCRIPTEN_ROOT_PATH "$ENV{EMSCRIPTEN}")
+endif()
+
+# Abort if not found. 
+if ("${EMSCRIPTEN_ROOT_PATH}" STREQUAL "")
+	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!")
+endif()
+
+# Normalize, convert Windows backslashes to forward slashes or CMake will crash.
+get_filename_component(EMSCRIPTEN_ROOT_PATH "${EMSCRIPTEN_ROOT_PATH}" ABSOLUTE)
+
+if ("${CMAKE_MODULE_PATH}" STREQUAL "")
+	set(CMAKE_MODULE_PATH "${EMSCRIPTEN_ROOT_PATH}/cmake")
+endif()
+
+set(CMAKE_FIND_ROOT_PATH "${EMSCRIPTEN_ROOT_PATH}/cmake")
+
+if (CMAKE_HOST_WIN32)
+	set(EMCC_SUFFIX ".bat")
 else()
-	set(CMAKE_FIND_ROOT_PATH "${EMSCRIPTEN_ROOT_PATH}")
+	set(EMCC_SUFFIX "")
 endif()
 
 # Specify the compilers to use for C and C++
 if ("${CMAKE_C_COMPILER}" STREQUAL "")
-	set(CMAKE_C_COMPILER "emcc.bat")
-	set(CMAKE_CXX_COMPILER "em++.bat")
-	set(CMAKE_AR "emar.bat")
-	set(CMAKE_RANLIB "emranlib.bat")
+	set(CMAKE_C_COMPILER "${EMSCRIPTEN_ROOT_PATH}/emcc${EMCC_SUFFIX}")
+endif()
+if ("${CMAKE_CXX_COMPILER}" STREQUAL "")
+	set(CMAKE_CXX_COMPILER "${EMSCRIPTEN_ROOT_PATH}/em++${EMCC_SUFFIX}")
+endif()
+
+if ("${CMAKE_AR}" STREQUAL "")
+	set(CMAKE_AR "${EMSCRIPTEN_ROOT_PATH}/emar${EMCC_SUFFIX}")
+endif()
+
+if ("${CMAKE_RANLIB}" STREQUAL "")
+	set(CMAKE_RANLIB "${EMSCRIPTEN_ROOT_PATH}/emranlib${EMCC_SUFFIX}")
 endif()
 
+# Don't do compiler autodetection, since we are cross-compiling.
+include(CMakeForceCompiler)
+CMAKE_FORCE_C_COMPILER("${CMAKE_C_COMPILER}" Clang)
+CMAKE_FORCE_CXX_COMPILER("${CMAKE_CXX_COMPILER}" Clang)
+
 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
 set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE BOTH)
 set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
 
+# We would prefer to specify a standard set of Clang+Emscripten-friendly common convention for suffix files, especially for CMake executable files,
+# but if these are adjusted, ${CMAKE_ROOT}/Modules/CheckIncludeFile.cmake will fail, since it depends on being able to compile output files with predefined names.
+#SET(CMAKE_LINK_LIBRARY_SUFFIX "")
+#SET(CMAKE_STATIC_LIBRARY_PREFIX "")
+#SET(CMAKE_STATIC_LIBRARY_SUFFIX ".bc")
+#SET(CMAKE_SHARED_LIBRARY_PREFIX "")
+#SET(CMAKE_SHARED_LIBRARY_SUFFIX ".bc")
+#IF (NOT CMAKE_EXECUTABLE_SUFFIX)
+#	SET(CMAKE_EXECUTABLE_SUFFIX ".js")
+#endif()
+#SET(CMAKE_FIND_LIBRARY_PREFIXES "")
+#SET(CMAKE_FIND_LIBRARY_SUFFIXES ".bc")
+
+SET(CMAKE_C_USE_RESPONSE_FILE_FOR_OBJECTS 1)
+SET(CMAKE_CXX_USE_RESPONSE_FILE_FOR_OBJECTS 1)
+SET(CMAKE_C_USE_RESPONSE_FILE_FOR_INCLUDES 1)
+SET(CMAKE_CXX_USE_RESPONSE_FILE_FOR_INCLUDES 1)
+
+set(CMAKE_C_RESPONSE_FILE_LINK_FLAG "@")
+set(CMAKE_CXX_RESPONSE_FILE_LINK_FLAG "@")
+
 # Specify the program to use when building static libraries. Force Emscripten-related command line options to clang.
-set(CMAKE_CXX_ARCHIVE_CREATE "${CMAKE_CXX_COMPILER} -o <TARGET> -emit-llvm <LINK_FLAGS> <OBJECTS>")
-set(CMAKE_C_ARCHIVE_CREATE "${CMAKE_C_COMPILER} -o <TARGET> -emit-llvm <LINK_FLAGS> <OBJECTS>")
+set(CMAKE_CXX_ARCHIVE_CREATE "${CMAKE_CXX_COMPILER} ${CMAKE_START_TEMP_FILE} -o <TARGET> -emit-llvm <LINK_FLAGS> <OBJECTS>${CMAKE_END_TEMP_FILE}")
+set(CMAKE_C_ARCHIVE_CREATE "${CMAKE_C_COMPILER} ${CMAKE_START_TEMP_FILE} -o <TARGET> -emit-llvm <LINK_FLAGS> <OBJECTS>${CMAKE_END_TEMP_FILE}")
 
 # Set a global EMSCRIPTEN variable that can be used in client CMakeLists.txt to detect when building using Emscripten.
 # There seems to be some kind of bug with CMake, so you might need to define this manually on the command line with "-DEMSCRIPTEN=1".
 set(EMSCRIPTEN 1)
 
+# We are cross-compiling, so unset the common CMake variables that represent the target platform. Leave UNIX define enabled, since Emscripten
+# mimics a Linux environment.
+SET(WIN32)
+SET(APPLE)
+
+set(CMAKE_C_SIZEOF_DATA_PTR 4)
+set(CMAKE_CXX_SIZEOF_DATA_PTR 4)
+
 set(CMAKE_C_FLAGS_RELEASE "-DNDEBUG" CACHE STRING "Emscripten-overridden CMAKE_C_FLAGS_RELEASE")
 set(CMAKE_C_FLAGS_MINSIZEREL "-DNDEBUG" CACHE STRING "Emscripten-overridden CMAKE_C_FLAGS_MINSIZEREL")
 set(CMAKE_C_FLAGS_RELWITHDEBINFO "" CACHE STRING "Emscripten-overridden CMAKE_C_FLAGS_RELWITHDEBINFO")
diff --git a/cmake/Platform/Emscripten_unix.cmake b/cmake/Platform/Emscripten_unix.cmake
deleted file mode 100644
index 92a21fd1..00000000
--- a/cmake/Platform/Emscripten_unix.cmake
+++ /dev/null
@@ -1,24 +0,0 @@
-# On Unix platforms, we must specify the absolute path to emcc for cmake, having emcc in PATH will cause cmake to fail finding it.
-# The user must set the EMSCRIPTEN variable to point to the Emscripten root folder.
-
-# Try locating Emscripten root directory based on the location of this toolchain file.
-get_filename_component(GUESS_EMSCRIPTEN_ROOT_PATH "${CMAKE_CURRENT_LIST_FILE}/../../.." ABSOLUTE)
-if (EXISTS "${GUESS_EMSCRIPTEN_ROOT_PATH}/emcc")
-	set(EMSCRIPTEN_ROOT_PATH "${GUESS_EMSCRIPTEN_ROOT_PATH}")
-endif()
-
-# If not found, try if the environment variable Emscripten was set.
-if ("${EMSCRIPTEN_ROOT_PATH}" STREQUAL "")
-	if ("$ENV{EMSCRIPTEN}" STREQUAL "")
-		message(ERROR "Could not locate emcc and the environment variable EMSCRIPTEN has not been set! Please point it to Emscripten root directory!")
-	else()
-		set(EMSCRIPTEN_ROOT_PATH "$ENV{EMSCRIPTEN}")
-	endif()
-endif()
-
-set(CMAKE_C_COMPILER "${EMSCRIPTEN_ROOT_PATH}/emcc")
-set(CMAKE_CXX_COMPILER "${EMSCRIPTEN_ROOT_PATH}/em++")
-set(CMAKE_AR "${EMSCRIPTEN_ROOT_PATH}/emar")
-set(CMAKE_RANLIB "${EMSCRIPTEN_ROOT_PATH}/emranlib")
-
-include(${EMSCRIPTEN_ROOT_PATH}/cmake/Platform/Emscripten.cmake)