[Vm-dev] How to addGCRoot: ? help requested

[Igor Stasenko]

On 23 December 2012 22:25, Nicolas Cellier
<nicolas.cellier.aka.nice at gmail.com> wrote:
>
> Ah OK, thanks, I get it...
> Two questions remain:
>
> 1) how to access addGCroot: from within a SmartSyntaxInterpreterPlugin ?

interpreterProxy addGCroot: ...

> 2) when do you need to register (re-register)?
> - once at image startup ?
yes,at image boot time.
when session changes.

> - after each snapshot ?
>
not here

> I think I'll have a look at NativeBoost indeed...
>
> Nicolas
>
> 2012/12/23 Igor Stasenko <siguctua at gmail.com>:
>>
>> addGCRoot()
>> takes a pointer to some memory location, where root object will be stored.
>>
>> sqInt * mem;
>>
>> mem = malloc(4);
>> *mem = someOop;
>> addGCRoot(mem);
>>
>> now, to read a reference to 'someObject' at any place you can just do
>>
>> someOop = *mem.
>>
>> often you may want to register multiple objects for use.
>> you can , of course, use addGCRoot() per each of them,
>> or, just use an array to store unlimited number of objects as roots
>> (that way you don't risk overflowing extra roots table, as well as can manage
>> that array at image side, and at cost of extra indirection).
>>
>> If you want a working example you can look at NBExtraRootsRegistry
>> implementation,
>> which is part of NativeBoost, how i using it.
>>
>> On 23 December 2012 21:34, Nicolas Cellier
>> <nicolas.cellier.aka.nice at gmail.com> wrote:
>>>
>>> I wanted to experiment a plugin and need to register a couple of
>>> classes that some primitive will test/instantiate.
>>> The ugly way is to pollute specialObjectArray...
>>> But #recreateSpecialObjectsArray recommend using addGCRoot()
>>> Fine, I'd like to try.
>>>
>>> What I'd like to do is register my couple of classes in a
>>> primRegister() primitive
>>> (once for all or at each image startup, or at each snapshot, whatever...)
>>> Then to later use the registered classes in primDoSomething().
>>>
>>> I can see ObjectMemory>>addGCRoot: but unfortunately, absolutely no
>>> sender of it to serve as an example...
>>> I even don't know how to access the objectMemory from within a
>>> SmartSyntaxInterpreterPlugin ?
>>> I can only see a interpreterProxy and
>>>
>>> Then how to retrieve my registered objects? they are store in the
>>> extraRoots at some index, but that index is not returned by
>>> addGCRoot:...
>>> Anyway, the index could change thanks to removeGCRoot:, so I'm stuck here...
>>> I must be missing something...
>>> Or maybe addGCRoot: is just here to prevent an Object to be garbage
>>> collected but does not really offer a registering service...
>>>
>>> If you know about any documentation/example hanging around or have
>>> some clues I'll be happy that you share them !
>>>
>>> Last note, I'm in a VMMaker oscog flavour...
>>>
>>> Nicolas
>>
>>
>>
>> --
>> Best regards,
>> Igor Stasenko.



-- 
Best regards,
Igor Stasenko.