Date: Sun, 22 Feb 2004 21:35:26 -0800 From: Peter Wemm <peter@wemm.org> To: freebsd-amd64@freebsd.org Subject: Re: CFLAGS+= -fPIC per default? Message-ID: <200402222135.26975.peter@wemm.org> In-Reply-To: <20040222185208.GA53610@dhcp01.pn.xcllnt.net> References: <BD6DAE5F-64A6-11D8-ACAA-000A95BAD088@raisdorf.net> <200402220033.01795.peter@wemm.org> <20040222185208.GA53610@dhcp01.pn.xcllnt.net>
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On Sunday 22 February 2004 10:52 am, Marcel Moolenaar wrote: > On Sun, Feb 22, 2004 at 12:33:01AM -0800, Peter Wemm wrote: > > On Saturday 21 February 2004 07:43 pm, Hendrik Scholz wrote: > > > On Feb 21, 2004, at 9:59 PM, Christian Weisgerber wrote: > > > > Why are these shared objects not built with -fPIC in the first > > > > place? > > > > > > Ask the authors of the third party applications :) > > > Most architectures don't need -fPIC and/or it slows them down > > > (thanks for the > > > comment Peter!). > > > > Yes, exactly. Some folks thought it would be an idea to add a flag > > to libtool to force it to link non-pic code into shared libraries. > > Essentially this reduces the sharability since we do relocations on > > the text segment, but the flipside is that its faster on i386 and > > on some libraries they figured it was worth burning extra memory > > that would be wasted by not using -fPIC. > > Not to mention that people generally attach -fPIC to the kind of > library they are making and thus do not build with -fPIC if they > create an archive library (the BSD make infrastructure has this > too). This most of the time works, but not when the archive library > is subsequently linked *into* a shared library later on. So, the > use of -fPIC is determined by how the object files are eventually > used to make up a process and that's not always known to the person > writing the libraries, let alone some (in)convenience tools like > libtool or automake/autoconf. Since you mentioned the BSD make infrastructure.. thats what we produce the _pic.a files for. eg: libc_pic.a, libgcc_pic.a etc. We even have a Makefile knob for it.. INSTALL_PIC_ARCHIVE.. if I remember the name correctly. -- Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com "All of this is for nothing if we don't go to the stars" - JMS/B5
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