GSoC 2016 - Precise GC

[Pham via Digitalmars-d-announce]

On Friday, 6 May 2016 at 09:06:59 UTC, Dmitry Olshansky wrote:
> On 06-May-2016 05:37, Jeremy DeHaan wrote:
>> On Wednesday, 4 May 2016 at 12:42:30 UTC, jmh530 wrote:
>>> On Wednesday, 4 May 2016 at 02:50:08 UTC, Jeremy DeHaan wrote:
>>>
>>> You can identify safe functions with
>>> https://dlang.org/phobos/std_traits.html#isSafe
>>> or
>>> https://dlang.org/phobos/std_traits.html#functionAttributes
>>
>> All I meant was that I don't know enough about what the 
>> compiler does
>> with built in types to make this work. It almost sounds like 
>> we would
>> need a safe union and unsafe union type and do some extra 
>> stuff for the
>> unsafe union, but I'm just starting to learn about this stuff.
>
> I'd note that a union without pointers doesn't hurt precise 
> scanner, it's only the ones with pointers that are bad.

Union is an user-defined-kind value and only user codes can tell 
the difference. I believe this will also effect the reference 
count implementation. I suggest that when a type has a union 
member, it should create a function such as gcValues with a 
parameter of output range of record (offset: size_t, type: 
typeid). the function should return that info based on whatever 
the actual value of those pointer types.  If that function is 
missing, use conservative approach as before

Cheers
Pham