RFC: [build, ada] Centralize PICFLAG configuration

Arnaud Charlet charlet@adacore.com
Tue Aug 16 18:04:00 GMT 2011


> Ok, I see.  Perhaps gcc/ada could be disentangled and those files
> exclusively or primarily used for libgnat/libgnarl moved over to libada,
> and referenced from there for the host build?

That would require some delicate work on AdaCore's side, so wouldn't be
helpful in the short term (rather harmful actually).

> > So passing PICFLAG down to the gcc/ada/gcc-interface Makefile and not
> > just via libada/Makefile is indeed important.
> 
> This seems to be easy: unless I'm mistaken, it should suffice to just
> call GCC_PICFLAG in gcc/configure.ac and substitute the result in
> gcc/ada/gcc-interface/Makefile.in.  What's the best way to test this?

You can e.g. add some dummy target in the Makefile that will echo
the value of this variable.

> I've often had serious trouble when I tried to run make
> gnatlib/gnatlib-shared in gcc/ada.

Apparently "someone" in the past removed too many things from the Makefile
which broke partly this support (probably thinking that with libada/Makefile,
these changes were not needed anymore). We have local changes at AdaCore in the
Makefile that basically ignores these changes.

> OTOH, it seems you're fine with the general approach of only passing
> PICFLAG to build gnatlib, not everything else that happens to reside in
> TARGET_LIBGCC2_CFLAGS?

I think that would be fine, although I'm not 100% sure. I can't remember
whether we've needed TARGET_LIBGCC2_CFLAGS for other flags on e.g. some
exotic/non mainstream platform in the past, so can't guarantee that this change
is a good idea. I'd say worth a try, asa long as we're prepared to have a
"plan B" in case this change does break some exotic platforms unexpectedly.

Arno



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