Re: automake -vs- huge projects (1st patch)

[Thomas Fitzsimmons]

On Sat, 2003-12-27 at 21:25, Alexandre Duret-Lutz wrote:
> >>> "adl" == Alexandre Duret-Lutz <address@hidden> writes:
> 
> [...]
>  adl> 1999-11-22  Tom Tromey  <address@hidden>
>  adl> 
>  adl>         * automake.in (handle_single_transform_list): Generate explicit
>  adl>         rule for subdir objects.  Fixes new addition to subobj.test.
> [...]
>  adl> The other side of the coin is that dependency tracking will not
>  adl> work anymore, because the dependency stuff for subdir/X.o should
>  adl> go into subdir/.deps/X.Po but the default suffix rule will put
>  adl> it in ./.deps/subdir/X.Po.
> [...]
>  Tom> Hmm, maybe this is the issue from way back.
> 
>  adl> I'm not sure about this.  In the past dependencies were put in
>  adl> .deps/subdir/X.Po (i.e. where the suffix rule--at least
>  adl> today--would put them).  You moved them to subdir/.deps/X.Po on
>  adl> 2002-01-20 for PR/224.
> 
> I've just noticed that the above change of 1999-11-22 occurs
> just after the merge of user-dep-gen-branch.  So perhaps you
> were right to think the issue was related to dependency
> tracking...
> 
> Anyway, here is a first patch that disables explicit rules for
> subdir-objects without per-target flags.
> 
> Random notes:
>   - folding the depfile&tmpdepfile computation into depcomp shorten
>     the "screen garbage" resulting from the invocation of depcomp
>     by one line.  This applies to all non-fastdep compilation,
>     not only subdir-objects.
>   - computing $depbase on-the-fly in fastdep rules adds one line
>     of output, so I've arranged things so that it is only used
>     when subdir-objects is set.  
>   - the test suite passes with GNU Make, and I've run the 14 tests
>     that uses subdir-objects with BSD Make (will start a full
>     check momently).  Apart from this I have not yet tested this
>     on a real project.  I'm hoping you can test this on libgcj.
>   - If you omit the NEWS chunk, the patch should also apply to
>     automake-1.8 vanilla.

I tested this patch with libgcj.  A test build worked fine, and
Makefile.in is *much* smaller (1.4M as opposed to 10M).  The size could
still be reduced further though.  I discussed the following with Tom on
IRC:

- all libgcj objects are listed in am__libgcj_la_SOURCES_DIST which is
included in DIST_SOURCES.  Adding the no-dist option doesn't prevent the
SOURCES_DIST and DIST_SOURCES variables from being generated, even
though they are not used anywhere.  Tom has a patch that may fix this;
I'm going to try it out.

- I've eliminated all non-essential per-target flags, but one libgcj
library still requires them.  For this library, .obj, .o and .lo targets
are generated, where .lo targets alone would suffice.

- Tom suggested that DEP_FILES may be redundant.  He suggested that
configure read the list of .Plo files from the am__include lines in
Makefile.in.

Anyway, this patch brings us closer to using automake-1.8 for libgcj. 
Thanks!

Tom