Re: Problem with catching exceptions on ARM

[Mathias Bauer]

Hi,

Am 21.02.14 11:06, schrieb Mathias Bauer:

> The program does not continue if an exception is thrown and caught in
> a function and then another exception is thrown in that same function
> and shall be caught in a function above on the call stack (the
> typical "rethrow" scenario).
>
> From debugging the code I could see that in this case the function
> "internal_objc_personality" in eh_personality.c only finds a handler
> that is a cleanup, and so the function is called again and again, always
> with the same result.

In case that helps:

For the first throw internal_objc_personality is called once in the 
"search phase". This is true for X86 and for ARM as well.

On an X86 system internal_objc_personality is called twice in the 
"search phase" after the second throw. In the first call the 
action_record passed to check_action_record is NULL, in the second call 
it isn't. Thus a handler_type is returned then and the program continues.

On ARM the action_record passed in to check_action_record is NULL in 
*every* call from internal_objc_personality, so check_action_record 
always returns NULL and internal_objc_personality always returns 
_URC_CONTINUE_UNWIND. This process never stops.

Regards,
Mathias