[CMake] SuperBuild whoes

[Marcus D. Hanwell]

On Thu, Apr 21, 2011 at 9:44 AM, Michael Wild <themiwi at gmail.com> wrote:
> On 04/21/2011 02:45 PM, David Cole wrote:
>> On Thu, Apr 21, 2011 at 4:30 AM, Michael Wild <themiwi at gmail.com
>> <mailto:themiwi at gmail.com>> wrote:
>>
>>     On 04/21/2011 06:48 AM, Michael Wild wrote:
>>     > Hi all
>>     >
>>     > I'm trying to set up a SuperBuild here. Everything works nicely the
>>     > first time round I build the project. The only real problem I have is
>>     > that if I change the sources of one of the sub-projects, the
>>     SuperBuild
>>     > still thinks everything is up to date. Of course, this is fully
>>     > explainable by the fact that the SuperBuild knows nothing about the
>>     > internal dependencies of the sub-project, and since the stamp
>>     files are
>>     > all there and unchanged, it thinks everything is fine. How do I get
>>     > around this? Anybody got an idea?
>>     >
>>     > Thanks
>>     >
>>     > Michael
>>
>>
>>     Found it myself. For completeness and documentation purposes: Add a
>>     custom target which removes the *-complete (see ExternalProject.cmake on
>>     where it is located, it is a bit tricky) and -*configure stamps. Of
>>     course, it should always run and depend on the external project target.
>>
>>     The thing I'm struggling with now is installing the various sub-projects
>>     into the system. Seems like it is impossible to install an imported
>>     target [1], but guessing and hard coding the paths is also not very
>>     attractive, but probably the only way to go at the moment. If anybody
>>     has a better idea, please speak up...
>>
>> If your intent is *always* to run the configure and later steps of an
>> ExternalProject build, you can consider adding an extra custom step that
>> configure depends on, which does nothing, but ALWAYS runs... No need to
>> do any fancy scrounging of stamp files for this to work.
>>
>>
>> Something like:
>>
>> ExternalProject_Add(Proj1
>>   ...
>> )
>>
>> ExternalProject_Add_Step(Proj1 forceconfigure
>>   COMMAND ${CMAKE_COMMAND} -E echo "This custom external project step
>> forces the configure and later steps to run whenever a top level build
>> is done..."
>>   DEPENDEES download
>>   DEPENDERS configure
>>   ALWAYS 1
>>   )
>
> Mhm, I thought I already tried this, but will check again. Thanks for
> the input.

We were messing with stamps in Titan too...just tried this approach
and it worked well. I will update Titan and some other projects, as
this is a much cleaner solution.
>
> I also solved my installation problem. By having all sub-projects
> install into a common prefix, and thanks to the wonders of RPATH and
> install_name which can handle relative paths and thanks to the fact that
> install(EXPORT) generated files are also relocatable, I can simply do a
> install(DIRECTORY) in the super project ;-) The only thing that required
> some thinking was writing a relocatable XXXConfig.cmake file. I think I
> will update my tutorial on the WIKI to use a un-configured, relocatable
> XXXConfig.cmake file.
>
I have been using a common prefix in a new superbuild project I have
been working on, and I think this is a very clean approach. Coupled
with the relocatable Config files it allows you to keep things very
simple.

Marcus