On Mar 24 [11:21], Brad King wrote: > On 03/24/2015 05:46 AM, Nils Gladitz wrote: > > I am not very familiar with fortran myself but there was this discussion > > on the ninja mailing list that implied that this might also require > > changes to ninja itself: > > > > https://groups.google.com/d/msg/ninja-build/b1-AF3pRJuE/NkPDsO0C2IUJ > > That discussion concludes assuming that CMake scans source files > while generating the build files to generate the ordering dependencies. > It does not. There could be generated source files or header files > that are needed to get the ordering right. In the Makefile generator > we have a step to scan dependencies for a target after all its > dependencies are finished and its custom commands have executed. > This ensures generated files are available. Then CMake puts the > dependency scanning results in a place used by the actual compile > and link rules. > > [snip] > > I've been thinking about some ideas on how build.ninja rules > could express the dynamic scanning and update we need. Rather > than posting them now, perhaps the design process would benefit > from any independently developed ideas you may have.
>From what I understood from the conclusion of the discussion is indeed that it would require cmake to generate dependency files at build time. In a test setup, I have the following: build CMakeFiles/testninja.dir/prog.o.d: Fortran_DEPENDS_SCAN ../prog.f90 build CMakeFiles/testninja.dir/prog.o: Fortran_COMPILER ../prog.f90 | CMakeFiles/testninja.dir/prog.o.d DEP_FILE = CMakeFiles/testninja.dir/prog.o.d FLAGS = -cpp -I../ OBJECT_DIR = CMakeFiles/testninja.dir OBJECT_FILE_DIR = CMakeFiles/testninja.dir build ... build ... I skipped all the other files, but the pattern is the same. Then, there are these rules: rule Fortran_DEPENDS_SCAN command = f90deps $in $out description = Write Fortran dependencies to $out rule Fortran_COMPILER depfile = $DEP_FILE deps = gcc command = /usr/bin/f95 $DEFINES $FLAGS -c $in -o $out description = Building Fortran object $out In this case, a script 'f90deps' does the dependencies on the fly. Note that the Fortran_COMPILER rule is now missing any -MMD/-MT stuff. So, to do a similar thing with cmake, one would need to expose the cmake Fortran dependency scanner so that it can be invoked as e.g.: rule Fortran_DEPENDS_SCAN command = cmake scan_dependencies $in $out description = Write Fortran dependencies to $out but I don't know if turning the cmake executable into a build-time dependency scanner is feasible and/or acceptable. Steven -- Powered by www.kitware.com Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/cmake-developers
