Re: [PATCH v3] new option: object-shortname

Am 03.03.2017 um 16:06 schrieb Mathieu Lirzin:
> Hello,
>
> Thomas Martitz <[email protected]> writes:
>
>> 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).
> Having both recursive and non-recursive makefiles for the same files in
> the same project is somewhat weird.  :)

But IMO it works really nice (with my patches). It gives the best of 
non-recursive
automake while maintaining strong modularity per subdirectory.

> If the problem is that your co-workers want to be able to type 'make' in
> the repository they are in, what about generating wrapper Makefiles
> containing:
>
>    all:
>    	make -C ..

This is not the same. It weakens modularity of the subdirectories (can't 
be built individually, e.g. in git submodule scenarios) and needs manual 
tweaking for each target.

The "all" target isn't sufficient, there are lots of custom targets 
(some of which are recursive), then there is also other 
Automake-specific stuff like script files, EXTRA_DIST, CLEANFILES etc. 
which has to be handled. The subdirectories must contain Automake 
Makefile fragments as well.


>
>> 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
>                 ^^^
> You must initialize bin_PROGRAMS before using "+=" on it.

Yes, of course. My mail did not aim to present a valid setup. It was 
shortened to show the key points.

>
>> %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
> Maybe I have misinterpreted some of your instructions but this command
> fails for me with:
>
>    make: *** No rule to make target 'a.c', needed by 'prog_a-a.o'.  Stop.
>
> I have created a git repository that will let you reproduce what I have:
>
>    https://notabug.org/mthl/automake-shortname
>
> Please let me know what I missed

I have created a fork of your repository, which completes the setup:

   https://notabug.org/kugel/automake-shortname


The last commit adds the option, so you can see the effect.

Without the option, "make && make -C a" compiles a.c twice, to two
differently named object files (a/a_prog_a-a.o and a/prog_a-a.o). With
the option only one compilation takes place.

Please consider my patch. It's a small change to Automake but
the effect makes a huge difference to us.

Best regards.