[Soot-list] Inquiry on nullable variable tracking and potential null pointer analysis

[flanker017]

Sorry the code format is corrupted, reformatted as follows:


class A

{

    B getB(); // may return null

    void test1();

    void test2();

}


class C

{

      void test()

    {

    A a = A();

    B b = a.getB();  // track b

    b.test1();           //may trigger NPE - line X

    if (b != null )

    {

        b.test2();   //won’t trigger NPE - line Y

    }

    b.test2(); //may trigger NPE - line Z

    }

 }
Thanks for your help.

2014-07-15 1:24 GMT+08:00 flanker017 <flankerhqd017 at gmail.com>:

> Hi everyone:
>
> Thanks for your time
> and hope I can get a little help. I want to conduct a nullable variable /
> potential null pointer statement analysis on program partially similar to
> following code snippet:
>
> > class A
> > {
> > B getB(); // may return null
> > void test1();
> > void test2();
> > }
> >
> > class C
> > {
> >       void test()
> > {
> > A a = A();
> > B b = a.getB();  // track b
> > b.test1();           //may trigger NPE - line X
> > if (b != null )
> > {
> > b.test2();   //won’t trigger NPE - line Y
> > }
> > b.test2(); //may trigger NPE - line Z
> > }
> > }
>
> My problem is as follows: method getB in class A may return null, so I
> want find out statements that use b and may throw NPE, like line X and line
> Z. Because line Y has a null check as if-clause, line Y won’t throw NPE.
> This is just a simple demonstration, real world example will have
> interprocedure data flow on b.
>
> So I wonder which analysis or toolkit in soot I can employ? If not, how
> can I implement such an analysis? I've thought of def-use or taint but
> neither is feasible on this problem I think.
>
> Thanks for your time again.
>
> ________________________________
> Sincerely
>



-- 
Sincerely,
Flanker He (a.k.a. Qidan He)
Website: http://flanker017.me
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