Segfault with std.container.Array but not regular dynamic array

[Maxim Fomin]

On Wednesday, 28 November 2012 at 22:13:05 UTC, Dan wrote:
> On Wednesday, 28 November 2012 at 20:30:41 UTC, Maxim Fomin 
> wrote:
>> On Wednesday, 28 November 2012 at 18:08:59 UTC, Dan wrote:
>>
>> This code with version=bug produces garbage because of 
>> opAssign. It seems that opAssign is actually called before 
>> accessing map:
>>
>
> Maxim, thanks for looking more at this. This bug is not 
> affecting my work in any way - I'm just trying to learn more 
> about D and how to debug, and your responses are helpful.
>
> I've now built druntime and phobos with debug to see if I can 
> see what is going on more.
>
> For me the relevant assembly of your code looks like below. I 
> see the value in the assoc array get created and memset 
> initialized to 0 inside aaA.d function _aaGetX with this line:
>
>     memset(ptail + aligntsize(keytitsize), 0, valuesize); // 
> zero value
>
> Then between +62 and +102 it goes off the rails and upon entry 
> to opAssign *this* is likely garbage. I can't be certain 
> because the values I see are 0, which would be consistent with 
> 0 initialization - but could also just be luck. At this point I 
> wish I knew some assembly. Anyway, I don't know if it is a 
> problem with associative array code, per se, or the code 
> generated by the compiler when opAssign and/or postblit are 
> defined for the value type. I do know that if you have no 
> postblit and no opAssign there are no issues - even with a 
> destructor. This is consistent with the examples you have 
> shown, they have postblit and/or opAssign as well as the 
> RefCount code which has postblit and dtor. In both your example 
> crash and the RefCount crash the actual seg fault is in the 
> dtor accessing bogus data because as you pointed out it was not 
> correctly initialized.
>
> Thanks
> Dan
>
>  <skipped>

This doesn't look like assembly for previous source. Please 
provide the source for which you have assembly and tell which dmd 
options do you use.