[CMake] compile header file for precompiled gcc headers
Maik Beckmann
maikbeckmann at gmx.de
Mon Dec 18 03:25:40 EST 2006
Am Sonntag, den 17.12.2006, 21:55 +0100 schrieb klaas.holwerda:
> Hi,
>
> I want to get gcc to use precompiled headers.
> From http://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html
> i read that i need to compile a header file ( containing #includes to
> all others for instance ).
>
> I have this haeder file, how to compile it with Cmake?
>
> I tried CHECK_CXX_SOURCE_COMPILES( wxart2d.h DONNO )
>
> But that does not produce a "wxart2d.gch" file.
>
> Understand that i do not need to get an executable nor library.
>
> Does somebody know how to do it?
>
> Has someone already succeeded in using precompiled headers with gcc on
> Linux, any tips?
>
> Thanks,
>
> Klaas
Hello
Rosegarden (http://www.rosegardenmusic.com/) uses experimental PCH
support
http://rosegarden.svn.sourceforge.net/viewvc/rosegarden/trunk/rosegarden/cmake_admin/FindPCHSupport.cmake?revision=7699&view=markup
This macro works per directory. It adds a target for precompileing the
header and every C++ source is compiled using it.
I tweaked this version for applying PCH's per target (see attachment)
My version should be used like this:
<CMakeLists.txt>
add_executable(test test.cpp)
add_precompiled_header( test std_includes.h)
</CMakeLists.txt>
It's very experimental, but now my sources using boost.fusion compile
about 6-8 times faster than without PCH.
MfG Maik
-------------- 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 )
GET_FILENAME_COMPONENT(_name ${_input} NAME)
SET(_source "${CMAKE_CURRENT_SOURCE_DIR}/${_input}")
SET(_outdir "${CMAKE_CURRENT_BINARY_DIR}/${_name}.gch")
MAKE_DIRECTORY(${_outdir})
SET(_output "${_outdir}/${CMAKE_BUILD_TYPE}.c++")
STRING(TOUPPER "CMAKE_CXX_FLAGS_${CMAKE_BUILD_TYPE}" _flags_var_name)
SET(_compiler_FLAGS ${${_flags_var_name}})
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)
LIST(APPEND _compiler_FLAGS ${_directory_flags})
SEPARATE_ARGUMENTS(_compiler_FLAGS)
#MESSAGE("_compiler_FLAGS: ${_compiler_FLAGS}")
message("${CMAKE_CXX_COMPILER} ${_compiler_FLAGS} -x c++-header -o ${_output} ${_source}")
ADD_CUSTOM_COMMAND(
OUTPUT ${_output}
COMMAND ${CMAKE_CXX_COMPILER}
${_compiler_FLAGS}
-x c++-header
-o ${_output} ${_source}
DEPENDS ${_source} )
ADD_CUSTOM_TARGET(${_targetName}_gch DEPENDS ${_output})
ADD_DEPENDENCIES(${_targetName} ${_targetName}_gch)
#SET(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} "-include ${_name} -Winvalid-pch -H")
#SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -include ${_name} -Winvalid-pch")
SET_TARGET_PROPERTIES(${_targetName} PROPERTIES
COMPILE_FLAGS "-include ${_name} -Winvalid-pch"
)
ENDMACRO(ADD_PRECOMPILED_HEADER)
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