text relocations in mono (and threading in general?)

hi pipacs,

// #include <stdio.h>
#include <pthread.h>

__thread int v;
__thread int o;

int main(void) {
   v = 2342;
   o = 0;
   // printf("hullo wurld: var:%d off:%dn", v,
o);

#if 0

   do {
     __asm ("pushl %%ebx; call 1f; 1: popl %%ebx; addl

$_GLOBAL_OFFSET_TABLE_+[.-1b], %%ebx; movl "
"v"
"gotntpoff(%%ebx), %0; popl %%ebx;" :
"=r" (o));
   } while (0);

#endif

   // printf("hullo wurld: var:%d off:%dn", v,
o);

   return(0);
}


creates two text relocations:

0000068d  0000000e R_386_TLS_TPOFF
00000698  0000000e R_386_TLS_TPOFF

when compiled with gcc -c -fPIE -o test2.o test2.c
&& gcc -lpthread -pie 
-o test2 test2.o && ./test2 2>&1

  689:   51                      push   %ecx
  68a:   65 c7 05 00 00 00 00    movl   $0x926,%gs:0x0
  691:   26 09 00 00
  695:   65 c7 05 04 00 00 00    movl   $0x0,%gs:0x4
  69c:   00 00 00 00
  6a0:   b8 00 00 00 00          mov    $0x0,%eax


as you can see the text relocations come from assigning the
values to 
the thread variables.

question 1) am i doing something wrong with compiling this?
question 2) if i am not doing something wrong, is the
threading causzing 
deliberate text relocations?

question 3) if you could fix the compilation, can you fix
the stuff 
between the #if 0 so that it doesn't cause a text relocation
too?

the original macro is this:

#define MONO_THREAD_VAR_OFFSET(var,offset) do { int tmp;
__asm ("call 
1f; 1: popl %0; addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %0; movl
" #var 
"gotntpoff(%0), %1" : "=r" (tmp),
"=r" (offset)); } while (0)

int main(void) {
   printf("hullo wurld: var:%d off:%dn", v, o);

   MONO_THREAD_VAR_OFFSET(v,o);

   // printf("hullo wurld: var:%d off:%dn", v,
o);
   return(0);
}

you can find it in the current mono sources:
mono-project.com (or org?)
source/trunk/mono/mono/utils/mono-compiler.h

the relocations are described here:
http://docsun.cites.uiuc.edu/sun_docs/C/so
laris_9/SUNWdev/LLM/p62.html

Thanks for your help,


Alex
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