Re: DConf 2013 Day 2 Talk 5: A Precise Garbage Collector for D by Rainer Schütze

[Rainer Schuetze]

On 12.06.2013 15:38, Juan Manuel Cabo wrote:
> On 06/05/2013 10:23 AM, Andrei Alexandrescu wrote:
>> Reddit: http://www.reddit.com/r/programming/comments/1fpw2r/dconf_2013_day_2_talk_5_a_precise_garbage/
>>
>> Hackernews: https://news.ycombinator.com/item?id=5825320
>>
>> Twitter: https://twitter.com/D_Programming/status/342269600689430529
>>
>> Facebook: https://www.facebook.com/dlang.org/posts/651801198166898
>>
>> Youtube: http://youtube.com/watch?v=LQY1m_eT37c
>>
>> Please drive discussions on the social channels, they help D a lot.
>>
>>
>> Andrei
>
>
> Loved this talk.

Thanks.

>
> Would struct have an extra field in memory pointing to the
> needed type info? If all of this is implemented, will this
> mean that an array of structs will not have their data contiguous
> in memory?

A struct allocated on the heap does not need the type info in memory, it 
is passed with the call invoked by "new" and it is used to supply the 
bitmap of pointers that is copied to the appropriate memory.

Due to the implementation details of arrays, it is a bit different for 
them: The memory layout changes slightly depending on the size of the 
array, so it is not the allocation that creates the pointer bitmap, but 
the array functions call "emplace" to fill the bitmap from an array type 
info. The memory layout of the array itself is unchanged.