Re: [rvm-research] Regarding Address of Object Reference in Field section of Object

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Hari,

Just to clarify, you want to add a single bit of metadata to each
object reference ?

The "simplest"[1] solution is to use one of the two low-order bits of
each object reference (objects are always (at least) 4-byte aligned).
 In order to do this you'll need a read barrier that masks out this
bit so that the mutator always sees aligned pointers, and a write
barrier that reinstates the metadata.

Alternatively, if this is too expensive, I'd suggest adding additional
space to the object via the classloader - how easy this is depends on
how you want to use the data, how much space you're prepared to use etc.

cheers

[1] Read barriers are never simple :-/

On 14/01/14 12:01, Hari Krishnan wrote:
> Hi ,
> 
> I want to set a bit, toggle a bit and test a bit in the section
> where each address of the instance field (object references) saved
> in objects. Is there any bit that I can use in each object fields
> for this purpose?
> 
> Cheers Hari Krishnan
> 
> 
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