[CMake] Poor performance of copy_if_different

Robert Dailey rcdailey.lists at gmail.com
Tue Nov 6 13:46:01 EST 2012 

Is there an assumption here that CMAKE_CONFIGURATION_TYPES will not be
set for single-configuration generators?

I have some code in my root CMake script that forces only 'debug' and
'release' configurations to exist (I didn't want the MinRelSize and
friends in there). I think this will force the logic that depends on
CMAKE_CONFIGURATION_TYPES to fail. What would you do in this case?

Here is the code that sets CMAKE_CONFIGURATION_TYPES:

cmake_minimum_required( VERSION 2.8.8 FATAL_ERROR )

set( CMAKE_BUILD_TYPE debug )
set( CMAKE_CONFIGURATION_TYPES debug release CACHE INTERNAL "" FORCE )

project( gmms )

... etc ...

On Tue, Nov 6, 2012 at 12:41 PM, Clinton Stimpson <clinton at elemtech.com> wrote:
>
> You could base your logic on CMAKE_CONFIGURATION_TYPES and CMAKE_BUILD TYPE.
>
> For example:
>
> if(CMAKE_CONFIGURATION_TYPES)
>   foreach(type ${CMAKE_CONFIGURATION_TYPES})
>     make_copy_rules(${type})
>   endforeach()
> else()
>   make_copy_rules(${CMAKE_BUILD_TYPE})
> endif()
>
> On Tuesday, November 06, 2012 12:34:22 PM Robert Dailey wrote:
>> I figured out the problem.
>>
>> On single-configuration generators (like NMake, which I'm testing now)
>> both release and debug configurations have the same binary output
>> directory. Since I'm creating 1 custom target (and corresponding
>> commands) per configuration, the 2nd configuration has the same
>> outputs as the 1st, so the 2nd target fails because I"m adding
>> different rules to the same output file. This isn't a problem with
>> Visual Studio generators because my outputs go to Debug and Release.
>>
>> Know any good workarounds for this?
>>
>> On Tue, Nov 6, 2012 at 11:54 AM, Clinton Stimpson <clinton at elemtech.com>
> wrote:
>> > Try this:
>> >     add_custom_command(
>> >
>> >         OUTPUT ${bin_outputs}
>> >         COMMAND ${copy_commands}
>> >         DEPENDS ....
>> >
>> >     )
>> >
>> > On Tuesday, November 06, 2012 11:50:54 AM Robert Dailey wrote:
>> >> Thanks Clinton,
>> >>
>> >> Here is what I have so far:
>> >>
>> >>
>> >> project( copy_dlls )
>> >>
>> >> set( copycmd "${CMAKE_COMMAND}" ARGS "-E" "copy_if_different" )
>> >>
>> >> set( configurations debug release )
>> >> foreach( config ${configurations} )
>> >>
>> >>     string( TOUPPER ${config} upper_config )
>> >>
>> >>     get_property( binarydirs GLOBAL PROPERTY
>> >>
>> >> THIRD_PARTY_DIRS_${upper_config} ) foreach( dir ${binarydirs} )
>> >>
>> >>         file( GLOB binaries "${dir}/*${CMAKE_SHARED_LIBRARY_SUFFIX}" )
>> >>
>> >>         if( WIN32 AND config STREQUAL "debug" )
>> >>
>> >>             file( GLOB pdbs "${dir}/*.pdb" )
>> >>             list( APPEND binaries ${pdbs} )
>> >>
>> >>         endif()
>> >>
>> >>         foreach( bin ${binaries} )
>> >>
>> >>             get_filename_component( bin_file ${bin} NAME )
>> >>
>> >>             list( APPEND bin_outputs ${bin} )
>> >>             list( APPEND copy_commands
>> >>
>> >>                 COMMAND ${copycmd} "${bin}"
>> >>
>> >> "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${CMAKE_CFG_INTDIR}/${bin_file}"
>> >>
>> >>             )
>> >>
>> >>         endforeach()
>> >>
>> >>     endforeach()
>> >>
>> >>     add_custom_command(
>> >>
>> >>         OUTPUT ${bin_outputs}
>> >>         ${copy_commands}
>> >>
>> >>     )
>> >>
>> >>     add_custom_target( copy_dlls_${config}
>> >>
>> >>         COMMENT "Copying ${config} binaries..."
>> >>         DEPENDS ${bin_outputs}
>> >>
>> >>     )
>> >>
>> >> endforeach()
>> >>
>> >>
>> >> This doesn't seem to work though, CMake tells me:
>> >>
>> >> CMake Error: Attempt to add a custom rule to output
>> >> "C:/Work/rdailey-hp/dpd-cmake/build-nmake-vc9/third_party/bdb/4.7.25/vc9s
>> >> p1/ debug/bin/libdb47d.dll.rule" which already has a custom rule.
>> >>
>> >> I'm trying to stuff all the copy commands and output files into 1
>> >> custom command, and wrap that with a custom target, so I can make
>> >> other targets depend on the custom target.
>> >>
>> >> On Tue, Nov 6, 2012 at 11:44 AM, Clinton Stimpson <clinton at elemtech.com>
>> >
>> > wrote:
>> >> > add_custom_command(
>> >> >
>> >> >   OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/my.dll
>> >> >   COMMAND cmake -E copy ${CMAKE_CURRENT_SOURCE_DIR}/my.dll
>> >> >
>> >> > ${CMAKE_CURRENT_BINARY_DIR}/my.dll
>> >> >
>> >> >   DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/my.dll
>> >> >   )
>> >> >
>> >> > add_custom_target(copy_dll ALL DEPENDS
>> >> > ${CMAKE_CURRENT_BINARY_DIR}/my.dll)
>> >> >
>> >> > Whether you use 1 custom command per dll, or 1 for all dlls, is up to
>> >> > you.
>> >> >
>> >> >  If they usually change together, then you could have fewer custom
>> >> >
>> >> > commands.  In that case, the OUTPUT would have multiple files and both
>> >> > DEPENDS would have multiple files.
>> >> >
>> >> > Another alternative is to use add_custom_command(TARGET POST_BUILD ...)
>> >> > if
>> >> > these are dlls that you compile yourself and need to copy after the
>> >> > build
>> >> > step.
>> >> >
>> >> > On Tuesday, November 06, 2012 11:23:03 AM Robert Dailey wrote:
>> >> >> Also, is it safe to add 1 custom command for each DLL copy? Or would
>> >> >> you somehow only use 1 custom command and copy them all with it? Also
>> >> >> would I add the custom commands to the custom target?
>> >> >>
>> >> >> On Tue, Nov 6, 2012 at 11:11 AM, Clinton Stimpson
>> >> >> <clinton at elemtech.com>
>> >> >
>> >> > wrote:
>> >> >> > On Tuesday, November 06, 2012 11:06:45 AM Robert Dailey wrote:
>> >> >> >> I use ${CMAKE_COMMAND} -E copy_if_different to copy DLL files to my
>> >> >> >> binary output directory. The custom target runs this command about
>> >> >> >> 50-100 times (for that many files).
>> >> >> >>
>> >> >> >> I notice that when all files are already copied, the commands still
>> >> >> >> run extremely slowly. It takes just as long to copy all the files
>> >> >> >> as
>> >> >> >> it does to copy none of them.
>> >> >> >>
>> >> >> >> I used the Sysinternals tool called Process Monitor to see what
>> >> >> >> CMake
>> >> >> >> is doing as it runs copy_if_different. It's opening the full file
>> >> >> >> and
>> >> >> >> seems to be comparing actual contents instead of something simple,
>> >> >> >> such as timestamp.
>> >> >> >>
>> >> >> >> I do not need such a thorough check, I simply want the check to see
>> >> >> >> which timestamp is higher and copy if the source is newer than the
>> >> >> >> target.
>> >> >> >>
>> >> >> >> Any reason why copy_if_different is so slow? Is my assumption
>> >> >> >> correct?
>> >> >> >> How can I make it faster?
>> >> >> >
>> >> >> > How about using plain "cmake -E copy ..." and rely on the timestamp
>> >> >> > check
>> >> >> > done by a custom command (add_custom_command()).
>> >> >> > You need to make sure the input/ouput parts of the custom command
>> >> >> > are
>> >> >> > set
>> >> >> > correctly so it can do a timestamp check.
>> >> >> >
>> >> >> > --
>> >> >> > Clinton Stimpson
>> >> >> > Elemental Technologies, Inc
>> >> >> > Computational Simulation Software, LLC
>> >> >> > www.csimsoft.com
>> >> >> > --
>> >> >> >
>> >> >> > Powered by www.kitware.com
>> >> >> >
>> >> >> > Visit other Kitware open-source projects at
>> >> >> > http://www.kitware.com/opensource/opensource.html
>> >> >> >
>> >> >> > Please keep messages on-topic and check the CMake FAQ at:
>> >> >> > http://www.cmake.org/Wiki/CMake_FAQ
>> >> >> >
>> >> >> > Follow this link to subscribe/unsubscribe:
>> >> >> > http://www.cmake.org/mailman/listinfo/cmake
>> >> >
>> >> > --
>> >> > Clinton Stimpson
>> >> > Elemental Technologies, Inc
>> >> > Computational Simulation Software, LLC
>> >> > www.csimsoft.com
>> >> > --
>> >> >
>> >> > Powered by www.kitware.com
>> >> >
>> >> > Visit other Kitware open-source projects at
>> >> > http://www.kitware.com/opensource/opensource.html
>> >> >
>> >> > Please keep messages on-topic and check the CMake FAQ at:
>> >> > http://www.cmake.org/Wiki/CMake_FAQ
>> >> >
>> >> > Follow this link to subscribe/unsubscribe:
>> >> > http://www.cmake.org/mailman/listinfo/cmake
>> >
>> > --
>> > Clinton Stimpson
>> > Elemental Technologies, Inc
>> > Computational Simulation Software, LLC
>> > www.csimsoft.com
>> > --
>> >
>> > Powered by www.kitware.com
>> >
>> > Visit other Kitware open-source projects at
>> > http://www.kitware.com/opensource/opensource.html
>> >
>> > Please keep messages on-topic and check the CMake FAQ at:
>> > http://www.cmake.org/Wiki/CMake_FAQ
>> >
>> > Follow this link to subscribe/unsubscribe:
>> > http://www.cmake.org/mailman/listinfo/cmake
> --
> Clinton Stimpson
> Elemental Technologies, Inc
> Computational Simulation Software, LLC
> www.csimsoft.com
> --
>
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.cmake.org/mailman/listinfo/cmake

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