Re: [rvm-research] Instrumenting machine codes to find memory addresses

Hi Shashank,

It's hard to say without seeing exactly how you instrumented "new." It 
seems tricky (or at least different from instrumenting other accesses) 
since the instrumentation presumably occurs after the allocation, 
whereas read/write instrumentation occurs before the access if you're 
following Pacer's approach. To instrument after an allocation, it seems 
like you'd want the instrumentation to push the address (which is on the 
stack) onto the stack *again* so it's both the top and next element on 
the stack, and then call your instrumentation method. For better 
feedback, please show the code for exactly how you instrumented "new." :)

Cheers,
Mike

On 04/28/2013 02:14 PM, Shashank Gupta wrote:
> Hi,
>
> We are inserting some machine codes in the machine code array of a 
> sample Java program running on Jikes RVM dynamically. We want to find 
> the memory addresses accessed, and hence inserted our own instructions 
> to calls a function within Jikes passing address as an argument. We 
> are using an approach almost similar as done in Pacer Patch in Jikes 
> Archive.
>
> It was working for simple programs without constructors of a separate 
> class being called. However in case of using "new" operator for 
> creating instance of a class, we are either getting sysFail error or a 
> Null Pointer Exception.
>
> What might be possible reasons for this?
>
> Thanks
>
> -- 
> Shashank Gupta
> 4th Year, B.Tech
> Department of Computer Science and Engineering
> Indian Institute of Technology Delhi
>
>
>
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