gcc&cmake: precompiled header support

CMakeLists.txt

@@ -1034,6 +1034,23 @@ foreach(FLAG ${OC_CXX_FLAGS_DEBUG})
 	set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} ${FLAG}" CACHE STRING "Flags used by the compiler during debug builds." FORCE)
 endforeach()
 
+############################################################################
+# Precompiled header support, gcc part (it needs the cxx flags)
+############################################################################
+
+include(GccPchSupport.cmake)
+if(CMAKE_COMPILER_IS_GNUCXX)
+	if(NOT DEFINED USE_GCC_PCH)
+		message("Using GCC precompiled headers! USE_GCC_PCH=Off to disable.")
+	endif()
+	option(USE_GCC_PCH "Use GCC precompiled headers" ON)
+endif()
+if(USE_GCC_PCH)
+	add_precompiled_header(clonk src/C4Include.h)
+	add_precompiled_header(c4group src/C4Include.h)
+	#c4script is rarely compiled and
+endif()
+
 ############################################################################
 # Locate optional libraries (if so desired)
 ############################################################################

GccPchSupport.cmake

@@ -0,0 +1,83 @@
+#Copied from http://www.mail-archive.com/cmake@cmake.org/msg04394.html which copied it from the rosengarden project
+#see also: http://gcc.gnu.org/onlinedocs/gcc-4.0.4/gcc/Precompiled-Headers.html
+
+MACRO(ADD_PRECOMPILED_HEADER _targetName _input )
+
+	# Prepare environment
+	if(CMAKE_BUILD_TYPE)
+		SET(_proper_build_type ${CMAKE_BUILD_TYPE})
+	else()
+		SET(_proper_build_type Standard)
+	endif()
+	GET_FILENAME_COMPONENT(_name ${_input} NAME)
+	SET(_pchdir "${CMAKE_CACHEFILE_DIR}/CMakeFiles/pch.custom.dir")
+	SET(_source "${CMAKE_CURRENT_SOURCE_DIR}/${_input}")
+	SET(_outdir "${_pchdir}/${_name}.gch")
+	MAKE_DIRECTORY(${_outdir})
+	string(REPLACE "/" "_" _inputescaped ${_input})
+	SET(_output "${_outdir}/${_inputescaped}_${_targetName}_${_proper_build_type}.o")
+	#FILE(WRITE "${_pchdir}/${_name}" "\#error Precompiled header not used")
+
+	# Assemble the compiler command with which future stuff will be built
+	STRING(TOUPPER "CMAKE_CXX_FLAGS_${CMAKE_BUILD_TYPE}" _flags_var_name) # Don't worry: CMake won't use any of the R/D/RWDI/MSR vars if the build type is not defined
+	if(CMAKE_CXX_COMPILER_ARG1) # please, know what you're doing if you rely on this...
+		STRING(STRIP ${CMAKE_CXX_COMPILER_ARG1} _ccache_tweak)
+		SET(_ccache_tweak "\"${_ccache_tweak}\"")
+	endif()
+	SET(_compiler_FLAGS ${_ccache_tweak} ${CMAKE_CXX_FLAGS} ${${_flags_var_name}})
+	if(CMAKE_BUILD_TYPE)
+        if(${CMAKE_BUILD_TYPE} STREQUAL "Debug")
+            LIST(APPEND _compiler_FLAGS "-D_DEBUG")
+        endif()
+	endif()
+	GET_TARGET_PROPERTY(_compile_defines ${_targetName} COMPILE_DEFINITIONS)
+	if(_compile_defines)
+		FOREACH(item ${_compile_defines})
+			STRING(REPLACE "\"" "\\\"" item ${item})
+			LIST(APPEND _compiler_FLAGS "-D${item}")
+		ENDFOREACH(item)
+	endif()
+	GET_TARGET_PROPERTY(_compile_defines ${_targetName} COMPILE_DEFINITIONS_${CMAKE_BUILD_TYPE})
+	if(_compile_defines)
+		FOREACH(item ${_compile_defines})
+			STRING(REPLACE "\"" "\\\"" item ${item})
+			LIST(APPEND _compiler_FLAGS "-D${item}")
+		ENDFOREACH(item)
+	endif()
+	GET_DIRECTORY_PROPERTY(_compile_defines COMPILE_DEFINITIONS)
+	if(_compile_defines)
+		FOREACH(item ${_compile_defines})
+			STRING(REPLACE "\"" "\\\"" item ${item})
+			LIST(APPEND _compiler_FLAGS "-D${item}")
+		ENDFOREACH(item)
+	endif()
+	GET_DIRECTORY_PROPERTY(_compile_defines COMPILE_DEFINITIONS_${CMAKE_BUILD_TYPE})
+	if(_compile_defines)
+		FOREACH(item ${_compile_defines})
+			STRING(REPLACE "\"" "\\\"" item ${item})
+			LIST(APPEND _compiler_FLAGS "-D${item}")
+		ENDFOREACH(item)
+	endif()
+	GET_DIRECTORY_PROPERTY(_directory_flags INCLUDE_DIRECTORIES)
+	FOREACH(item ${_directory_flags})
+		LIST(APPEND _compiler_FLAGS "-I\"${item}\"")
+	ENDFOREACH(item)
+	GET_DIRECTORY_PROPERTY(_directory_flags DEFINITIONS)
+	STRING(REPLACE "\"" "\\\"" _directory_flags ${_directory_flags}) # Welcome to escape hell. Replace " with \"
+	LIST(APPEND _compiler_FLAGS ${_directory_flags})
+	SEPARATE_ARGUMENTS(_compiler_FLAGS)
+	list(REMOVE_DUPLICATES _compiler_FLAGS)
+
+	# Add a target with the pch
+	ADD_CUSTOM_COMMAND(
+		OUTPUT ${_output}
+		COMMAND "${CMAKE_CXX_COMPILER}"
+			${_compiler_FLAGS} -x c++-header -o ${_output} ${_source}
+		IMPLICIT_DEPENDS CXX ${_source}
+	)
+	ADD_CUSTOM_TARGET(${_targetName}_pch DEPENDS ${_output})
+	ADD_DEPENDENCIES(${_targetName} ${_targetName}_pch)
+	INCLUDE_DIRECTORIES(BEFORE ${_pchdir})
+	#SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Winvalid-pch" CACHE STRING "C++ compiler flags" FORCE)
+
+ENDMACRO(ADD_PRECOMPILED_HEADER)