------- Additional Comments From cnmnzusoib at mailinator dot com 2007-08-09 22:01 ------- > That is exactly the behaviour you get with --whole-archive. Except that --whole-archive brings in *everything*. Is there even a point to using the static archive at that point vs. doing an intermediate link to combine into a .o? I'm actually kind of curious where whole-archive came from, as it seems like a quick hack to address this very problem...
What I'm driving at here is to find a way to get the benefit of faster links via static archive (by leaving unnecessary stuff out), without skipping initializers with side effects in translation units which *are* being used... (thus making those initializers implicitly referenced) Ideally, only those with external side effects are needed, but I don't think that level of information is available to the linker...? Assuming it isn't, you wind up importing anything with any kind of initialization section. Still better than choosing between non-functional code or importing everything. And it looks like it'll be pretty effective, and not bother system libraries. Of the 94 .a files under /usr/lib on a fairly basic Ubuntu box, comprising 5581 object files, only 19 (a third of a percent!) had .ctor sections. So even if it's not optimal, its much better than what we have now. I'm still kind of hoping there's a more selective way to detect which units have a side effect in an already-used unit. If this is something to take up with the compiler venders (i.e. emit a new section with the needed information) then so be it, at least then you can leave the ball in their court. Also, there's also a side issue of awareness/documentation -- having a flag whose purpose is to make sure all the init sections are run raises awareness that some initialization routines might *not* be run if you don't use it. Seeing as how I found quite a few threads where people have run into this problem, e.g.: http://gcc.gnu.org/ml/gcc-bugs/2004-06/msg02196.html http://cygwin.com/ml/cygwin/2007-02/msg00584.html http://lists.apple.com/archives/xcode-users/2005/Aug/msg00786.html ("I don't think ld is smart enough") http://www.physicsforums.com/archive/index.php/t-106619.html ("This doesn't work" and the thread never does seem to figure out what's going on) http://ciaranm.org/show_post/13 ("evil and broken ", references --as-needed and DSO, but same issue) http://mail.opensolaris.org/pipermail/dtrace-discuss/2005-August/000207.html ("strangeness with respect to archives and .init processing") ...even just documentation would help avoid wasting people's time. You should understand that when "the rest of us" write a static initializer, especially something explicit like __attribute__((constructor)), we do actually expect it to run, regardless of whether it's linked via an archive or not. People don't expect using an archive vs. other formats to change their results. I don't think they *should* expect that, not for something as basic and explicitly covered by the standards as "will the initializer be run?". It's clear in the above threads that even of the people who understand the problem, it's *not what even they ideally want it to do*. > But note that the very popular operating systems Windows > and Mac OS X are not ELF based. True, OS X calls them __StaticInit and __constructor/__destructor sections and uses Mach-O, but either binutils already has code for parsing that or else it doesn't matter anyway... I don't know about Windows though, but it's entirely possible different platforms might need different solutions. OS X's ld has -all_load instead of --whole-archive, for instance. (sigh) -ethan PS I'm switching the severity and summary back to a 'bug' since I still consider this a fixing a design flaw more than "enhancement". Shouldn't matter to you since it's still closed anyway... -- What |Removed |Added ---------------------------------------------------------------------------- Severity|enhancement |normal Summary|add --all-init flag to force|don't skip initializers with |all static initializers to |visible external side |be loaded |effects in static archives http://sourceware.org/bugzilla/show_bug.cgi?id=4538 ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is. _______________________________________________ bug-binutils mailing list bug-binutils@gnu.org http://lists.gnu.org/mailman/listinfo/bug-binutils
