[Soot-list] How to get field object in Jimple code?

[Eric Bodden]

Hi.

I think in general you are interested in points-to analysis or alias analysis.

Soot has a local must-alias analysis:
http://www.sable.mcgill.ca/soot/doc/soot/jimple/toolkits/pointer/LocalMustAliasAnalysis.html

That can tell you whether two local variables must point to the same object.

Eric

--
Dr. Eric Bodden
Software Technology Group, Technische Universität Darmstadt, Germany
Tel: +49 6151 16-5478    Fax: +49 6151 16-5410
Mailing Address: S2|02 A209, Hochschulstraße 10, 64289 Darmstadt



On 28 April 2010 01:57, Sai Zhang <racezhang at gmail.com> wrote:
>
> Hi all:
>
> I am a bit confused on how to extract "field object" from Jimple code (used
> in a field-sensitive dynamic analysis).
>
> For instance, consider the following simple class and the corresponding
> jimple code:
>
> class A {
>   Object s  = "string";
> }
>
> //client code:
> A a1 = new A();
> a1.s = "hello";
> A a2 = a;
> a2.s = "world";      // a2.i should be the same field as a1.i
>
>
> //(roughly) corresponding jimple code for client code
> 1.   $r1 = new A;
> 2.   r2 = $r1
> 3.   r2.<A: string s> = "hello";
> 4.   r3 = $r1
> 5.   r3.<A: string s> = "world"
>
>
> Is there a way to fetch the object of "A.s" (not the field reference, e.g.
> SootField , SootFieldRef) from line 3 and line 5?
>
> For instance, could I could insert some instrumentation code after line 5,
> like:
> Tracer.record( .....r3.<A:string s> (// get the object of A.s),...);
>
>
> In other words, is there anyway to decide a2.s and a1.s are pointing to the
> same memory location in a dynamic analysis? In my intuition,
> it should not be that hard, since r2 and r3 seem to share the same
> JimpleLocal object, right? but how to get the state of "A.s" seems
> to be a problem. Is there any good way to overcome that? or am i in a wrong
> direction?
>
>
> Thanks so much.
>
>
> - Sai
>
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