On Wednesday, 9 October 2013 at 06:05:52 UTC, dennis luehring
wrote:
Am 09.10.2013 07:23, schrieb PauloPinto:
Apple dropped the GC and went ARC instead, because they never
managed to make it work properly.
It was full of corner cases, and the application could crash if
those cases were not fully taken care of.
Or course the PR message is "We dropped GC because ARC is
better"
and not "We dropped GC because we failed".
Now having said this, of course D needs a better GC as the
current one doesn't fulfill the needs of potential users of the
language.
the question is - could ARC be an option for automatic memory
managment
in D - so that the compiler generated ARC code when not using
gc - but using gc-needed code?
or is that a hard to reach goal due to gc-using+arc-using lib
combine problems?
Personally I think ARC can only work properly if it is handled by
the compiler, even if D is powerful enough to have them as
library types.
ARC is too costly to have it increment/decrement counters in
every pointer access, in time and cache misses.
Objective-C, Rust and ParaSail do it well, because ARC is built
into the compiler, which can elide needless operations.
Library solutions like C++ and D suffer without compiler support.
Personally, I think it could be two step:
- Improve the GC, because it what most developers will care about
anyway
- Make the D compilers aware of RefCounted and friends, to
minimize memory accesses, for the developers that care about
every ms they can extract from the hardware.
--
Paulo
