Makefile - compiling back and forth

问题

Following is the directory structure of my project:

                       expt-main
                       ---------
                       Makefile_main
                    /             \
         subdir-1                    subdir-2
         --------                    --------
         Makefile_1                  Makefile_2
         mod_codeA.f90               mod_code1.f90
         mod_codeB.f90               mod_code2.f90
         mod_codeC.f90               mod_code3.f90

Makefile_main:

export

SHELL = /bin/sh

F90     = mpxlf95

SRCDIRS = $(subdir-1) $(subdir-2)

all:
        @for DIR in ${SRCDIRS} ;

          do \
            back=`pwd`; \
            cd $$DIR ;\
            $(MAKE) ; status=$$? ; \
            if [ $$status != 0 ] ; then \
              echo "Exit status fro make was $$status" ; exit $$status ; \
            fi ; \
            cd $$back ; \
         done

-------------------------------------------------------------------------------

Makefile-1:

%.o: %.f90
        $(F90) $(F90FLAGS) -I$(subdir-2) -c $<

mod_codeA.o: mod_codeC.o $(subdir-2)/mod_code2.o

-------------------------------------------------------------------------------

Makefile-2:

PROG = $(exec)

subdir-1_objs = $(subdir-1)/mod_codeA.o mod_codeB.o mod_codeC.o

all: $(PROG)

$(PROG): $(subdir-2_objs) $(subdir-1_objs) -o $@ $(subdir-2_objs) $(subdir-1_objs)

---------------------------------------------------------------------------------

I've written the Makefile_main such that it compiles the codes (modules) in subdir-1 first and then the ones in subdir-2 and finally makes the executable. The issue: modules in subdir-1 uses modules from subdir-2 and in similar fashion, modules in subdir-2 uses those in subdir-1. My make is getting failed because the modules being used is in other directory. How to write a makefile which will take care of this issue that is, while compiling modules in subdir-1, whenever it encounters the need for an object file from subdir-2, it should switch to subdir-2 compile the necessary modules and return back to subdir-1 for further action?

回答1:

If modules in different subdirectories need each other as you say, then this is not a good use of recursive Make.

Do away with Makefile-1 and Makefile-2, and let Makefile_main do all the work. (I can't tell you specifically how to change Makefile-main, since I don't do Fortran, I don't understand Makefile-2, and I don't see any dependency of modules in subdir-2 upon those in subdir-1).

回答2:

If you want to stick to this directory layout and still keep three separated Makefiles, then you can use compiler flags to instruct the FORTRAN compiler to put module files into a common directory of your choice.

For instance using:

$ gfortran --version
GNU Fortran (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
Copyright (C) 2011 Free Software Foundation, Inc.

you can use -I and -J flags to instruct the compiler on:

where to search for module files (.mod)
where to put generated module files

That said I think that the suggestion given by Beta to join the Makefiles makes a lot of sense. To know some of the reasons why you should do that you can read this paper.

Finally, as your project seems not to be very large at this stage, I also suggest to take into consideration CMake as a build system, as it possibly provides a more convenient way of specifying dependencies between targets (as well as many other things).

来源：https://stackoverflow.com/questions/12893738/makefile-compiling-back-and-forth

标签

makefile

fortran90