Re: RFC: [build, ada] Centralize PICFLAG configuration

[Paolo Bonzini <bonzini at gnu dot org>]

On 08/15/2011 10:53 AM, Rainer Orth wrote:
> * The general approach between libtool and libiberty differs.  Unless
>    otherwise specified (PIC is the default or doesn't work for some
>    reason), libtool defaults to -fPIC, while libiberty has a strange
>    mixture of -fPIC/-fpic and nothing, without explanation and without a
>    default.

I guess it's kind of historic, probably to produce smaller/faster code 
on PPC and SPARC which differentiate between -fPIC/-fpic.

In general I trust libtool more, but -fPIC/-fpic differences should be 
more or less harmless, and this:

> * For SPARC, libiberty/configure.ac has
>
> 	case "${CFLAGS}" in
> 	    *-fpic*)
> 		PICFLAG=-fpic
> 		;;
> 	    *)
> 		PICFLAG=-fPIC
> 		;;
> 	esac ;;

actually makes some sense---so the general approach in your patch is 
good.  The patch is okay.

> > Yes, that needs to be done of course.  I'm not sure if we still support
> > gnatlib_and_tools to build libada/gnattools.  If so, we would need the
> > PICFLAG to be available somehow in the gcc Makefile (perhaps by providing
> > GCC_TARGET_PICFLAG in addition to GCC_PICFLAG in picflag.m4).
>
> The only trace I could find is in a install.texi reference to historical
> practice.

Yes, but it also matters whether AdaCore is using it.  If so, I'd like 
also to understand why.

Paolo