[patch] bfd/som.c: fix local buffer overrun (was: gas (binutils) 2.10: SIGSEGV on hppa1.1-hp-hpux10.20)

[Marco Franzen]

Correcting a mistake in my previous posting:

> >   > (Especially when you do an alloca in a nested scope, leave it and
> >   > enter another nested scope (as happens here): When re-using the stack space
> >   > of the old scope, whether the automatic space of the new scope (if larger)
> >   > might overlap with the alloca-ted area.)

That's what I meant (although expressed awkwardly). But my later example
wasn't:

> int f ()
> {
>   char *dynbuf = alloca (64);
>   {
>     char buf[1024];
>     dynbuf = alloca (8192);
>   }
>   {
>     char smallbuf[25];

Make this 
      char bigbuf[4096];
or there is no chance at all of colliding with dynbuf, no matter how alloca
and the compiler interact.

>     assert (smallbuf+24 < dynbuf || dynbuf+8191 < smallbuf); 

Change this accordingly to
      assert (bigbuf+ sizeof bigbuf <= dynbuf || dynbuf + 8192 <= bigbuf);

>   }
> }

Sorry about the confusion.
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