[Soot-list] Obtained all aliased variables?

[Zhoulai]

Hi,

I happen to have the same need as Marc-André. Is there implementation code
that solves  this problem?

Zell.

On Sat, Feb 23, 2013 at 6:57 AM, Richard Xiao <richardxx at cse.ust.hk> wrote:

> Hi, Marc-Andre:
>
> I ever did an in-depth study on alias queries.
>
> The easiest and efficient way for your task is using an inversed points-to
> matrix. Suppose the points-to matrix (rows represent pointers, columns are
> objects) computed by SPARK is P, the transpose of P (pointed-to matrix) is
> PT. Therefore, for a querying pointer p, execute:
>
> <code>
>
> ans = empty
> foreach o in points-to set of p
>      ans = ans (union) PT[o]
>
> </code>
>
> That's to say, just extract all rows of PT that are the objects in the
> points-to set of p, and union these rows.
>
> Although this way does not achieve the lower bound for this problem, in
> practice, especially for Anderson's points-to result, it is very efficient.
>
> One more problem is that, maintaining P and PT is very cost. However,
> notice that many rows in P are identical (i.e. many identical points-to
> sets), you can compact P by merging the identical rows. Then, using the
> compressed matrix P to compute PT. Also for Anderson's analysis, this
> simple compression is very effective.
>
> Hope it helps.
>
> Regards,
> Xiao
>
>
>
> On Sat, Feb 23, 2013 at 12:09 AM, Marc-Andre Laverdiere-Papineau <
> marc-andre.laverdiere-papineau at polymtl.ca> wrote:
>
>> Hello,
>>
>> I would like to find out all the variables that are aliased to a given
>> variable.
>>
>>  From what I can see, this is not the first time ppl ask on the ML, and
>> the answer has always been to check for the intersection... (e.g
>> http://www.sable.mcgill.ca/pipermail/soot-list/2012-February/004107.html)
>>
>> So far, I have used the non-empty intersection check of the points-to
>> set, but that's a bit tedious to do when a program has a lot of
>> variables that are unrelated.
>>
>> Does anyone know how to get all the Local and SootField objects that are
>> aliased to a given Local/SootField? The only option I can think of is
>> traversing the PAG - but the API doesn't look very much suited for my
>> needs. Am I missing some magic visitor class???
>>
>> Regards,
>>
>> --
>> Marc-André Laverdière-Papineau
>> Doctorant - PhD Candidate
>> _______________________________________________
>> Soot-list mailing list
>> Soot-list at sable.mcgill.ca
>> http://mailman.cs.mcgill.ca/mailman/listinfo/soot-list
>>
>
>
>
> --
> Richard Xiao Xiao
> PhD Student @ CSE @ Hong Kong University of Science and Technology
> www.cse.ust.hk/~richardxx
>
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>
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