[CMake] compile header file for precompiled gcc headers

[Maik Beckmann]

Am Mittwoch, den 20.12.2006, 12:28 +0100 schrieb frederic heem:

> 
> Note that cmake has a bug in which it reports the error at FindXSD.cmake:55, 
> whereas the mistake is in PCHSupport.cmake. 
> Then the marco tries to copy the precompiled header to the build directory but 
> fails because the source file doesn't contain the full path, here is the 
> modification:
> 	ADD_CUSTOM_COMMAND(
> 		OUTPUT	${CMAKE_CURRENT_BINARY_DIR}/${_name} 
> 		COMMAND ${CMAKE_COMMAND} -E copy  ${CMAKE_CURRENT_SOURCE_DIR}/${_input} 
> ${CMAKE_CURRENT_BINARY_DIR}/${_name} # ensure same directory! Required by gcc
> 	)

First of all, ensure:
include_directories(
    ${CMAKE_CURRENT_BINARY_DIR}
    # ... all the others
)

I do it like this:

add_precompiled_header(my_target 
    ${PROJECT_SOURCE_DIR}/std_headers/ublas_std_header.h
)

Your modification forces me to copy ublas_std_header.h to the src-dir
where CMakeLists.txt is located.

In your case it should look like

add_precompiled_header(your_target 
    ${CMAKE_CURRENT_SOURCE_DIR}/std_header.h
)


greetz, Maik

PS: The attached versions reflects changes of CMAKE_CXX_FLAGS, which is
necessary for USE_FILE's like: 
include(${VTK_USE_FILE}) 


-------------- next part --------------
# - Try to find precompiled headers support for GCC 3.4 and 4.x
# Once done this will define:
#
# Variable:
#   PCHSupport_FOUND
#
# Macro:
#   ADD_PRECOMPILED_HEADER

IF(CMAKE_COMPILER_IS_GNUCXX)
    EXEC_PROGRAM(
    	${CMAKE_CXX_COMPILER} 
        ARGS 			--version 
        OUTPUT_VARIABLE _compiler_output)
    STRING(REGEX REPLACE ".* ([0-9]\\.[0-9]\\.[0-9]) .*" "\\1" 
           gcc_compiler_version ${_compiler_output})
    #MESSAGE("GCC Version: ${gcc_compiler_version}")
    IF(gcc_compiler_version MATCHES "4\\.[0-9]\\.[0-9]")
        SET(PCHSupport_FOUND TRUE)
    ELSE(gcc_compiler_version MATCHES "4\\.[0-9]\\.[0-9]")
        IF(gcc_compiler_version MATCHES "3\\.4\\.[0-9]")
            SET(PCHSupport_FOUND TRUE)
        ENDIF(gcc_compiler_version MATCHES "3\\.4\\.[0-9]")
    ENDIF(gcc_compiler_version MATCHES "4\\.[0-9]\\.[0-9]")
ENDIF(CMAKE_COMPILER_IS_GNUCXX)

MACRO(ADD_PRECOMPILED_HEADER _targetName _input )

	IF(NOT CMAKE_BUILD_TYPE)
		MESSAGE(FATAL_ERROR 
			"This is the ADD_PRECOMPILED_HEADER macro. " 
			"You must set CMAKE_BUILD_TYPE!"
		)
	ENDIF(NOT CMAKE_BUILD_TYPE)

    GET_FILENAME_COMPONENT(_name ${_input} NAME)
	GET_FILENAME_COMPONENT(_path ${_input} PATH)
    SET(_outdir "${CMAKE_CURRENT_BINARY_DIR}/${_name}.gch")
	SET(_output "${_outdir}/${CMAKE_BUILD_TYPE}.c++")

    ADD_CUSTOM_COMMAND(
		OUTPUT ${_outdir}
		COMMAND mkdir ${_outdir} # TODO: {CMAKE_COMMAND} -E ... 
	)
	#MAKE_DIRECTORY(${_outdir})
    
	STRING(TOUPPER "CMAKE_CXX_FLAGS_${CMAKE_BUILD_TYPE}" _flags_var_name)
    SET(_compile_FLAGS ${${_flags_var_name}})
    
    GET_DIRECTORY_PROPERTY(_directory_flags INCLUDE_DIRECTORIES)
		

	SET(_CMAKE_CURRENT_BINARY_DIR_included_before_path FALSE)
	FOREACH(item ${_directory_flags})
		IF(${item}  STREQUAL ${_path} AND NOT _CMAKE_CURRENT_BINARY_DIR_included_before_path )
			MESSAGE(FATAL_ERROR 
				"This is the ADD_PRECOMPILED_HEADER macro. "
				"CMAKE_CURREN_BINARY_DIR has to mentioned at INCLUDE_DIRECTORIES's argument list before ${_path}, where ${_name} is located"
			)	
		ENDIF(${item}  STREQUAL ${_path} AND NOT _CMAKE_CURRENT_BINARY_DIR_included_before_path )
	
		IF(${item}  STREQUAL ${CMAKE_CURRENT_BINARY_DIR})
			SET(_CMAKE_CURRENT_BINARY_DIR_included_before_path TRUE)
		ENDIF(${item}  STREQUAL ${CMAKE_CURRENT_BINARY_DIR})
	
		LIST(APPEND _compile_FLAGS "-I${item}")
    ENDFOREACH(item)

	GET_DIRECTORY_PROPERTY(_directory_flags DEFINITIONS)
    LIST(APPEND _compile_FLAGS ${_directory_flags})
	LIST(APPEND _compile_FLAGS ${CMAKE_CXX_FLAGS} )

    SEPARATE_ARGUMENTS(_compile_FLAGS)
    #MESSAGE("_compiler_FLAGS: ${_compiler_FLAGS}")
	#message(${_compile_FLAGS} )
    #message("COMMAND ${CMAKE_CXX_COMPILER}	${_compile_FLAGS} -x c++-header -o ${_output} ${_input}")
	
	ADD_CUSTOM_COMMAND(
		OUTPUT	${CMAKE_CURRENT_BINARY_DIR}/${_name} 
		COMMAND ${CMAKE_COMMAND} -E copy  ${_input} ${CMAKE_CURRENT_BINARY_DIR}/${_name} # ensure same directory! Required by gcc
	)

    ADD_CUSTOM_COMMAND(
        OUTPUT ${_output} 	
		COMMAND ${CMAKE_CXX_COMPILER}
				${_compile_FLAGS}
				-x c++-header
				-o ${_output} 
				${_input}
        DEPENDS ${_input} ${_outdir} ${CMAKE_CURRENT_BINARY_DIR}/${_name}	
	)
   	ADD_CUSTOM_TARGET(${_targetName}_gch 
		DEPENDS	${_output} 	
	)
    ADD_DEPENDENCIES(${_targetName} ${_targetName}_gch )
    SET_TARGET_PROPERTIES(${_targetName} 
		PROPERTIES	
			COMPILE_FLAGS "-include ${_name} -Winvalid-pch"
    )
	
	
ENDMACRO(ADD_PRECOMPILED_HEADER)