Plan for Exceptions and @nogc?

[via Digitalmars-d]

On Wednesday, 18 February 2015 at 09:04:38 UTC, Matthias Bentrup 
wrote:
> If you want to avoid lookup tables, you can of course 
> add/remove catchers dynamically whenever you enter/leave a try 
> block, that would add a small cost to every try, but avoids the 
> (larger) table lookup cost on the catch.

There are many ways to get better performance than the current 
regime, both dynamic and static approaches, with little execution 
costs, but since most C++ programs don't rely on exceptions where 
speed matters there is little incentive to improve considering 
the complications in the backend. So I don't expect the C++ crowd 
to do anything about it.

As a result C++ programmers that need speed can keep pretending 
exceptions don't exist, and if you don't need speed, why are you 
using C++? :-). Thus status quo persists and nothing interesting 
happens.

D has made C/C++ compatibility a goal... so nothing is going to 
happen with D either...

In most programs the possible call trees at a given point are 
quite limited, like a regular expression, so with whole program 
optimization you only need to special case catch blocks where the 
program may stop unwinding. I.e. you could detect which of the 
possible call trees you are in and unwind "multiple stack frames" 
from the same code location. If only a few functions can call 
you, you most certainly don't need to look up anything, right? If 
the compiler is allowed to move beyond "the peephole separate 
compilation viewpoint"...