Illegal instruction on m68k nommu

[Lennart Sorensen]

On Thu, Apr 16, 2009 at 04:03:51PM -0400, Lennart Sorensen wrote:
> So I have traced it down to a call in crtstuff.c in gcc 4.3.3:
> 
>   {
>     /* Safer version that makes sure only .dtors function pointers are
>        called even if the static variable is maliciously changed.  */
>     extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden")));
>     static size_t dtor_idx;
>     const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1;
>     func_ptr f;
> 
>     while (dtor_idx < max_idx)
>       {
>         f = __DTOR_LIST__[++dtor_idx];
>         f ();
>       }
>   }
> 
> The call to 'f ();' is where it hits the illegal instruction.
> 
> How do I add print statements or something else that I can use to debug
> code in this area.
> 
> I have suspicions about the calculation of max_idx, since it seems to want
> to calculate the number of entries, yet I think it is using addresses
> in it's calculation, which seems like it ought to give a larger value
> than intended.

I also see in the objdump of my test program:

00000460 l     O .data  00000000 __DTOR_LIST__
0000046c l     O .data  00000000 .hidden __DTOR_END__

So they seem to be 3 addresses apart, while the code looks like it
assumes they are sequential.  I doubt there are any actual destructors
called in my 'return 42' test program.

-- 
Len Sorensen