Ada: VPATH in ada/Makefile.adalib

Ada: VPATH in ada/Makefile.adalib

[Florian Weimer]

After some tweaking, I've been able to build the GNAT run-time
library. However, the build process now stops because ada/Makefile
assumes that the ada/rts/ subdirectory contains all *.o files:

	$(AR) $(AR_FLAGS) rts/libgnat$(arext) \
	   $(addprefix rts/,$(GNATRTL_NONTASKING_OBJS) $(LIBGNAT_OBJS))

This is not true, some of the *.o files are not built because of the
use of VPATH in ada/Makefile.adalib.

In addition, the rules for the library targets in Makefile.adalib
should probably look like this:

    libgnat.a: $(GNAT_OBJS)
            $(AR) r libgnat.a $^

(So that the VPATH substitution is performed by make.)  But I'm not a
make expert, and I no longer intend to become one.

BTW, I guess this one of the reasons why recursive make is considered
harmful. ;-)

Re: Ada: VPATH in ada/Makefile.adalib

[Geert Bosch]

On Fri, 5 Oct 2001, Florian Weimer wrote:

  After some tweaking, I've been able to build the GNAT run-time
  library. However, the build process now stops because ada/Makefile
  assumes that the ada/rts/ subdirectory contains all *.o files:
  
  	$(AR) $(AR_FLAGS) rts/libgnat$(arext) \
  	   $(addprefix rts/,$(GNATRTL_NONTASKING_OBJS) $(LIBGNAT_OBJS))
  
  This is not true, some of the *.o files are not built because of the
  use of VPATH in ada/Makefile.adalib.

Makefile.adalib is not used for building the library in a normal build.
It is meant for cases where one wants to rebuild the library after installation,
which may be the case if you'd want to change the compilation options.

  -Geert

Re: Ada: VPATH in ada/Makefile.adalib

[Laurent Guerby]

I suggest one more line of comment on top of ada/Makefile.adalib to
state that this is not used as part of the regular build process and
what it is there for (this can be infered from the described step but
is not stated clearly right now :).

-- 
Laurent Guerby <guerby@acm.org>

Re: Ada: VPATH in ada/Makefile.adalib

[Florian Weimer]

Geert Bosch <bosch@gnat.com> writes:

> On Fri, 5 Oct 2001, Florian Weimer wrote:
>
>   After some tweaking, I've been able to build the GNAT run-time
>   library. However, the build process now stops because ada/Makefile
>   assumes that the ada/rts/ subdirectory contains all *.o files:
>   
>   	$(AR) $(AR_FLAGS) rts/libgnat$(arext) \
>   	   $(addprefix rts/,$(GNATRTL_NONTASKING_OBJS) $(LIBGNAT_OBJS))
>   
>   This is not true, some of the *.o files are not built because of the
>   use of VPATH in ada/Makefile.adalib.
>
> Makefile.adalib is not used for building the library in a normal build.

Yes, you're right of course, but the problem seems to exist anyway,
and I think it is indeed related to the use if VPATH (Makefile[.in]
uses it, too).

Re: Ada: VPATH in ada/Makefile.adalib

[Florian Weimer]

Geert Bosch <bosch@gnat.com> writes:

> On Fri, 5 Oct 2001, Florian Weimer wrote:
>
>   After some tweaking, I've been able to build the GNAT run-time
>   library. However, the build process now stops because ada/Makefile
>   assumes that the ada/rts/ subdirectory contains all *.o files:
>   
>   	$(AR) $(AR_FLAGS) rts/libgnat$(arext) \
>   	   $(addprefix rts/,$(GNATRTL_NONTASKING_OBJS) $(LIBGNAT_OBJS))
>   
>   This is not true, some of the *.o files are not built because of the
>   use of VPATH in ada/Makefile.adalib.
>
> Makefile.adalib is not used for building the library in a normal build.

Okay, I now seem to understand what is going on.  I've got the source
in ~/src-cvs/gnu/gcc/, and a build directory ~/src-cvs/gnu/gcc/BUILD/
in the source tree.  Usually (i.e. for other targets), this works
well, however ~/src-cvs/gnu/gcc/BUILD/Makefile contains a VPATH
setting:

        VPATH = ../../../gcc/ada

During the compiler build process, this refers to the directory
~/src-cvs/gcc/gcc/ada/, but when make invokes itself recursively in
the directory ~/src-cvs/gnu/gcc/BUILD/gcc/ada/rts/, the VPATH forces
make to in ~/src-cvs/gnu/gcc/BUILD/gcc/ada/, where it finds some
already existing object files. :-/

Oh dear, I've just noticed that this kind of setup is officially
unsupported.  Oh well.