RCArray is unsafe
Zach the Mystic via Digitalmars-d
digitalmars-d at puremagic.com
Tue Mar 3 19:46:34 PST 2015
On Tuesday, 3 March 2015 at 21:37:20 UTC, Andrei Alexandrescu
> On 3/3/15 12:35 PM, Zach the Mystic wrote:
>> Isn't allocating and collecting a freelist also overhead?
> No. I don't have time now for a proof of concept and it seems
> everybody wants to hypothesize about code that doesn't exist
> instead of writing code and then discussing it.
>> The unoptimized lowerings would be:
>> auto tmp = myGlobal; // bump count
>> } // tmp destroyed, --count
>> auto tmp2 = c; // bump count
>> fun(c, c);
>> } // --count
>> The only addition is an optimization where the compiler elides
>> assignments and calls the add/release cycles directly.
> Do you have something reviewable, or just your own past posts?
Just my own past posts. My suggestion is based on the compiler
doing all the work. I don't know how it could be tested without
hacking the compiler.
> For the time being I want to move forward with DIP25 and
> deferred freeing.
That's fine. I like DIP25. It's a start towards stronger safety
guarantees. While I'm pretty sure the runtime costs of my
proposal are lower than yours, they do require compiler hacking,
which means they can wait.
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