[cmake-developers] Some advice

[James Bigler]

On Fri, Sep 16, 2011 at 5:11 AM, Alexander Neundorf <neundorf at kde.org>wrote:

> On Thursday, September 15, 2011 10:22:52 PM James Bigler wrote:
> > On Mon, Sep 12, 2011 at 3:35 PM, James Bigler <jamesbigler at gmail.com>
> wrote:
> > > I need some advice on how to fix a problem I'm having with files with
> the
> > > same name.
> > >
> > > I have two CUDA files with the same name in different directories:
> > >
> > > CUDA_ADD_EXECUTABLE(test-conflict
> > >
> > >   "path with spaces/conflict.cpp"
> > >   "path with spaces/conflict.cu"
> > >   "path with spaces/no-conflict.cpp"
> > >   "path with spaces/no-conflict.cu"
> > >   conflict-main.cpp
> > >   conflict.cpp
> > >   conflict.cu
> > >   )
> > >
> > > I notice that the cpp files get the following outputs:
> > >
> > > path with spaces/no-conflict.cpp: test-conflict.dir\Debug
> > > path with spaces/conflict.cpp:
> > > "test-conflict.dir\Debug\/path_with_spaces/conflict.cpp.obj"
> > > conflict.cpp: "test-conflict.dir\Debug\/conflict.cpp.obj"
> > >
> > > This seems to work well and everyone is happy.
> > >
> > > The FindCUDA code is a different story, and one I wish to get some more
> > > input on.  The current implementation takes the basename and merges it
> in
> > > with the target name like so (one example given):
> > >
> > >
> > >
> "${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}/${cuda_target}_generated
> > > _${basename}${generated_extension}"
> > >
> > > The problem is two files with the same basename can cause collisions in
> > > the naming scheme.  I'm wondering if the best solution is to keep a per
> > > target list of basenames as a directory property and when collisions
> > > happen, create a new sub-directory to be used by the build script.  My
> > > question at this point is what and how to compute the non-conflicting
> > > directories.  Does anyone have any good suggestions for how to
> implement
> > > this?
> > >
> > > Thanks,
> > > James
> >
> > How about telling me where I can find how CMake does this for the C code?
> > I notice that it only puts sub directories when there's a conflict, so
> > there's logic somewhere that determines this and then determines what the
> > intermediate directories should be.
>
> CMake creates a directory for every target, and inside that directory, it
> creates subdirectories for every subdirectory present in the input files.
> To avoid clashes between foo.c and foo.cpp, the .o is simply appended, so
> we
> get foo.c.o and foo.cpp.o.
>
> Alex
>

Thanks for the response Alex, but that's not quite it.  From my experiments,
CMake only puts object files in sub directories (below the target
sub-directory) when it detects the clash (see the original email).  I also
have clashes on file names and not just extensions.

I'm trying to figure out how to best handle the partial paths.

If you had this then I can compute the relative path with respect to
CMAKE_CURRENT_SOURCE_DIR.

dir1/file.cpp
dir2/file.cpp

What if I had this:

../dir1/file.cpp
../../dir2/file.cpp

What do I use as the sub directory?  I can't use ../ in the path as this
will totally put things in the wrong directory
(CMAKE_CURRENT_BINARY_DIR/CMakeFiles/target.dir/../dir1 would generally be a
bad idea).

And what if I had an absolute file path?  What do I do then?

James
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