Am 03.03.2017 um 10:19 schrieb Mathieu Lirzin:
Thomas Martitz <ku...@rockbox.org> writes:
Maybe I have to explain my use case better? Is it not clear to you?
Yes this is not clear to me. :)
A concrete example will hopefully help.
Thanks.
Here we go.
My use case is to make use of non-recursive Automake for faster build
times and global dependencies, while also generate subdirectory
Makefiles for the convenience of my co-workers, so that they can keep
running make only in the directories they work in (they do since since
15-20 years because our build system always used recursive Automake. I
can't just remove recursive Automake).
So the setup looks like this:
$ cat root/Makefile.am
include a/Makefile.am.inc
include b/Makefile.am.inc
$ cat root/a/Makefile.am
include Makefile.am.inc
$ cat root/a/Makefile.am.inc
bin_PROGRAMS += %D%/prog_a
%C%_prog_a_SOURCES = a.c
%C%_prog_a_CFLAGS = $(AM_CFLAGS)
$ cat root/b/Makefile.am
include Makefile.am.inc
$ cat root/b/Makefile.am
bin_PROGRAMS += %D%/prog_b
%C%_prog_b_SOURCES = b.c
This generates:
root/Makefile
root/a/Makefile
root/b/Makefile
where root/Makefile does *not* do recursive automake but knows about all
libs and programs.
This sort of works today, but there is one big problem (assume
subdir-objects is used)
$ cd root; make a/prog_a
# this compiles prog_a using a/a_prog_a-a.o
$ cd root/a; make prog_a
# this compiles prog_a _again_, using a/prog_a-a.o
As you can see, prog_a is compiled twice simply because the file name of
the object file is different. This is a big problem.
Now, one workaround would be to use _SHORTNAME
$ echo %C%_prog_a_SHORTNAME = a >> root/a/Makefile.am.inc
This very inconvinient, because it's only need as a workaround and is
needed in every Makefile.am.inc. But worse, is also unworkable because
_SHORTNAME does not work inside conditionals.
if ENABLE_PROG_A
include a/Makefile.am.inc
end
generates a Automake warning and generates an incorrect Makefile.in.
We do require Automake conditionals like this because of our modularity.
So my suggested fix is a new Automake option that applies the effect of
_SHORTNAME automatically without a single line of _SHORTNAME, and
without the defect when used inside a conditional. As a result, prog_a
is built from prog_a-a.o regardless of where make was invoked, and is
not built twice for two make invocations.
The ability to use _SHORTNAME to override even that is, of course, still
intact.
In the end, if my use case above works, then this would seem to be like
the ideal way to use Automake to me, since you can combine the best of
both worlds (recursive and non-recursive Automake).
Best regards
