Re: [rvm-research] question regarding raw memory access

Hi,

On 06.12.2016 18:51, Eliot Moss wrote:
> I can see two potential problems with that:
> 
> 1) You need to make sure that objectRef is not null.
On the Jikes RVM side, it's possible to check if objectRef is actually a valid reference by using validRef(ObjectReference) from DebugUtils from the org.jikesrvm.mminterface package. I'm not sure if there's a MMTk equivalent. If there isn't, you can write your own or add code to call it via the normal MMTk-Jikes RVM interface.

> 2) I wonder how you calculate size.  I observe that header words,
>     and as I recall, even the first field, of objects occur at
>     negative offsets.  You may be accessing beyond the end of an
>     object ...
I suppose it would be possible to do the size calculation using methods from ObjectModel.


Kind regards,

Erik Brangs

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