Re: Re: bug 828

["Jason Moxham" <jason@njkfrudils.plus.com>]

----- Original Message ----- 
From: "Jason Moxham" <jason@njkfrudils.plus.com>
To: <jason@njkfrudils.plus.com>
Sent: Monday, July 06, 2009 3:32 PM
Subject: Fwd: Re: bug 828


> ----------  Forwarded Message  ----------
>
> Subject: Re: bug 828
> Date: Monday 06 Jul 2009
> From: Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>
> To: pari-dev@list.cr.yp.to
>
> On Mon, Jul 06, 2009 at 02:22:01AM +0100, Jason Moxham wrote:
> > Hi
> >
> > I've been looking at bug 828  dynamic loading of a function in a static
> > build of pari.
> > Here is a guess based on my debug below , note the line numbers will not
> > match as I added a bit debugging stuff
> >
> > FILE ../src/kernel/none/level1.h LINE 109
> > FILE ../src/kernel/none/level1.h LINE 86 x is 1
> > avma=2147092636 bot=2143092744
> > FILE ../src/kernel/none/level1.h LINE 93
> > FILE ../src/kernel/none/level1.h LINE 98
> > FILE ../src/kernel/none/level1.h LINE 109
> > FILE ../src/language/eval.c LINE 715
> > avma=2147092632 bot=2143092744
> > FILE ../src/language/eval.c LINE 723 65
> > FILE ../src/language/eval.c LINE 724
> > avma=2147092632 bot=2143092744
> > FILE ../src/language/eval.c LINE 723 65
> > FILE ../src/language/eval.c LINE 724
> > avma=2147092632 bot=2143092744
> > FILE ../src/language/eval.c LINE 723 95
> > FILE ../src/language/eval.c LINE 724
> > FILE ../src/language/eval.c LINE 1073
> > FILE ../src/language/eval.c LINE 1074
> > avma=2147092632 bot=2143092744
> > &avma=0x797bb0 &bot=0x797c40
> > ep is 0x113f420
> > epval is 0x1a2483a0
> > FILE ../src/kernel/none/level1.h LINE 494
> > avma=0 bot=0
> > &avma=0x1a594918 &bot=0x1a5949a8
> > avma=0 bot=0
> > FILE ../src/kernel/none/add.c LINE 66
> > FILE ../src/kernel/none/add.c LINE 68
> > FILE ../src/kernel/none/add.c LINE 70
> > FILE ../src/kernel/none/add.c LINE 72
> > avma=0 bot=0
> > FILE ../src/kernel/none/add.c LINE 75
> > avma=0 bot=0
> > FILE ../src/kernel/none/mp.c LINE 175
> > avma=0 bot=0
> > FILE ../src/kernel/none/mp.c LINE 178
> > FILE ../src/kernel/none/mp.c LINE 135
> > avma=0 bot=0
> > avma=0 bot=0
> > FILE ../src/kernel/none/level1.h LINE 470
> > FILE ../src/kernel/none/level1.h LINE 247
> > FILE ../src/kernel/none/level1.h LINE 233
> > FILE ../src/kernel/none/level1.h LINE 225
> > FILE ../src/kernel/none/level1.h LINE 142
> > FILE ../src/kernel/none/level1.h LINE 131
> > FILE ../src/kernel/none/level1.h LINE 86 x is 3
> > avma=0 bot=0
> > FILE ../src/kernel/none/level1.h LINE 89
> > FILE ../src/language/init.c LINE 926
> > FILE ../src/language/init.c LINE 947
> > FILE ../src/language/init.c LINE 834
> > FILE ../src/language/init.c LINE 836
> >      2 [main] gp-sta 5304 _cygtls::handle_exceptions: Error while dumping
> > state
> > (probably corrupted stack)
> > Segmentation fault (core dumped)
> >
> > It look like that when you load up the function addii from the dynamic
> > library it also loads up another copy of the varibles avma and bot ,
> > which are then accessed and of course the values they have are garbage.
>
> Interesting. What are exactly the linker flags used ?
> There are probably some linker flags that could fix that.
>
> Could you try to rebuild everything with -fPIC ? This cahnges the way
> global variables are linked, so it might make a difference here.
>
> Cheers,
> Bill.
>
> -------------------------------------------------------

If I'm reading this correctly there is no solution. Windows(and apparently 
some form of BSD) does not support functions in a dll reading global 
varibles in the original executible. Therefore our static build will never 
work in windows and we should disable that part of the test for windows. It 
works in the shared case as a dll can read a varible in another dll.

follow the the long threads below

http://sourceware.org/ml/cygwin/2004-04/msg00184.html

http://sourceware.org/ml/cygwin/2004-04/msg00351.html


Jason