Re: ada compiler?

[Robert A Duff <bobduff@shell01.TheWorld.com>]

Ludovic Brenta <ludovic@ludovic-brenta.org> writes:

> Georg Bauhaus wrote:
>> On Wed, 2007-11-14 at 07:09 -0800, Ludovic Brenta wrote:
>> > But if the stack is exhausted or nearly so (perhaps because the last
>> > in a long series of recursive calls raises Storage_Error), chances are
>> > high that the exception handler itself will overflow the stack (e.g.
>> > passing your string "Hey! You!" to a procedure might itself cause a
>> > stack overflow). This, in my view, greatly reduces the benefit of the
>> > exception. Also, what if raising the exception requires some stack
>> > space? Maybe I should have said that explicitly.
>>
>> No, these are matters of course, and they are mentioned in the RM.
>
> Not really. 11.5(23) says that a stack overflow raises Storage_Error
> but, since the stack has overflowed, I'm not convinced that the
> exception can still be raised, propagated and handled properly. The RM
> is silent about that part and I believe this is an implementation
> issue.

The RM requires that Storage_Error be raised.  So the implementation
must have a little bit of reserve stack space -- enough to do the raise
S_E, and then jump to whatever handler applies.  The stack is normally
chopped back when jumping to the handler, but there is no guarantee (in
the RM) that there's enough stack space to do whatever the handler does.
The handler might raise S_E itself.

- Bob