Hi Paul, * Paul Jakma wrote on Wed, Nov 30, 2005 at 08:13:14PM CET: > On Wed, 30 Nov 2005, Mike Frysinger wrote: > > >PIE and PIC arent the same thing
> The distinction between the two is mostly important at link-time. Ie > a collection of PIC and/or PIE objects can be linked together into a > PIE executable. > > What I'm curious about is what the difference is in generated /code/ > for an object /before/ linking done between PIC and PIE. Is there an > efficiency/performance gain in generating PIE code over PIC? Yes. > If so, is the gain over PIC sufficiently large to be relevant to > Ralf's patch My patch _enables you_ to take advantage of exactly this efficiency gain. > (which, if I understand correctly, will compile all code as PIC if > -fpie is supplied). Wrong. It will create a PIC .libs/foo.o and a PIE foo.o. > If efficiency of PIE targeted code is sufficiently greater than PIC, > then, AIUI, that would require libtool to distinguish between > additional modes of compiling objects intended for shared usage (PIC) > and not (PIE). > > Is my understanding anyway. > > Alternatively, projects would need to tailor their build systems to > make the distinction between possibly-intended-to-link-into-shared > and other ojbects. You haven't understood the patch. Please try it. It does _exactly_ the right thing, if you supply CFLAGS=-fpie: - all non-libtool-created objects will be PIE - all libtool-created objects will have one PIE and one PIC version. Only the latter will end up in shared libraries, only the former will end up in program binaries. Enjoy. :) (Do you want me to post a backport?) Cheers, Ralf _______________________________________________ http://lists.gnu.org/mailman/listinfo/libtool
