[Soot-list] my StrongLocalMustAliasAnalysis gives unexpected results

[Zhoulai]

Thanks Patrick. I see your point. Don't forget that your
StrongMustAliasAnalysis, as described by your 2008's paper, is supposed to
consider variable redefinition in loops!

For the k-th iteration of the loop, a new object o_k is created and bound
to x (which overwrites its earlier state) , so the "* states history* "
related to x will be
x->o_0, x -> o_2, x->o_k....
which mean that ***Over time*** x is bound to {o_0,o_1,o_2 ...}. I believe
this is the way your StrongMustAliasAnalysis in your paper reasons, right?

My apologies for any misunderstandings.
Zell.

On Sun, Oct 21, 2012 at 6:33 AM, Patrick Lam <plam at sable.mcgill.ca> wrote:

> On 10/21/2012 12:25 AM, Zhoulai wrote:
> >      > ****************
> >      > 1:     static void test5(int i){
> >      > 2:         while (i>0){
> >      > 3:             A x = new A();
> >      > 4:             A y = x;
> >      > 5:             String s = "hello";
> >      >          }
> >      >      }
> >      > **************
>
> > By your specification in your paper, the strong representative only
> > must-alias itself at the same program location if it is not guaranteed
> > that this representative represents a single run-time object.
> >
> > Here variable 'x'' is associated with  more than 1 run-time objects.  It
> > is therefore expected to be bound to UNKNOWN.
>
> x only points to one object at a time in this case. The only way that x
> might point to more than one object is if there are two different
> definitions that reach x (perhaps from different iterations of the
> loop), like if you had this program instead:
>
>      A x = null;
>      if (...) x = new A();
>      A y = x;
>
> Then you should not get UNKNOWN. But in the program you wrote, there's
> only one object that x could possibly contain.
>
> pat
>
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