Problems with shared library (-fPIC) and tango

[Thomas Leonard]

On Sun, 06 Jul 2008 03:31:44 +0000, Sean Kelly wrote:

> == Quote from e-t172 (e-t172 at akegroup.org)'s article
>> Lars Ivar Igesund a écrit :
>> > There is a ticket related to this somewhere. I believe I was told
>> > once that part of the problem is that _all_ of the runtime can't be
>> > part of the dynamic library, but that there needs to be a static
>> > portion too with at least main. The above issue may have more to do
>> > with the effect of PIC on the code though. It would be very good if
>> > it could be resolved.
>> IIRC, there is only one problem when trying to build Tango with -fPIC :
>> the garbage collector, which segfaults on collection. Fix the GC and
>> you have your Tango shared library.
> 
> I believe this is an issue with the static data segments not being
> represented in the way that the GC expects in a shared library.  I
> really need to do some research to figure out how things are different
> in this instance.  Though if someone knows then that would be good too
> :-)

Could that be why this program crashes?

import std.gc: fullCollect;
import mi = std.moduleinit;

int main(string[] args) {
	//printf("%p\n", mi._moduleinfo_dtors[6]);
	fullCollect();

	return 0;
}

If I uncomment the printf line, it works (I guess because the address 
gets left on the stack). Without calling fullCollect() explicitly, my 
programs work until the GC gets called, then they crash.

I'm using a (rather modified) GDC on Linux, with libgphobos2 as a shared 
library.

How are module variables like _moduleinfo_dtors supposed to get 
registered as roots with the GC?

Thanks,