On 11/23/2015 10:07 AM, Iain Buclaw via Digitalmars-d wrote:
Yes, the _d_dynamic_cast is redundant. This happened because the EH pointer was
treated as an Object, then upcasted to the catch type via the normal convert()
routines. This is what caused the unnecessary call to _d_dynamic_cast.
This switch statement is generated by GCC itself, and it tries to be
accommodating for all supported languages. I imagine that the default case is
there to support `catch(...)` in C++ code, however D has no notion of this
construct, so what is instead generated is _Unwind_Resume to tell unwind to keep
looking up the call chain.
In other words, the default case should never really happen in D code except in
the event of a logic bug in the unwind EH personality function (or possibly
corruption). If you feel it more appropriate, I don't see the harm in replacing
it with whatever HLT or abort instruction you like. :-)
Thanks, this helps a lot, and makes me a lot more comfortable with the notion
that I understand what is going on. I won't generate the cast, then, and I'll
use a HLT for the default.
BTW, are you working on supporting catching std::exception ?
My eevil plan is to get D exceptions working completely before trying to support
std::exception.
