[Soot-list] my StrongLocalMustAliasAnalysis gives unexpected results

[Eric Bodden]

Hi Zell.

Good question! Normally StrongLocalMustAliasAnalysis should tell you
that x not must-alias itself. (That's why the analysis is called
"strong".) To compute the right value, we use the class
StronglyConnectedComponentsFast to find SCCs. I wonder if that
implementation gets confused by your infinite loop. What happens if
you have a loop that actually has a chance of terminating?

Eric

On 11 October 2012 09:46, Zhoulai <zell08v at orange.fr> wrote:
> Hello,
>
> I probably wrongly understand the StrongLocalMustAliasAnalysis, but it gives
> me some unexpected results. Where am I wrong?
>
> For this program, I expect that 'x' does not strongly must-alias with itself
> in the scope of the method. This is because of the redefinition of 'x'.
> (reference: Bodden et al 2008's  "Objects Representative"paper)
>
> ************* ******************
>   static void test3(int i){
>                 A x;
>                 while (true){
>                      x= new A();
>                }
>      }
> *****************
>
> However, if my analysis driver program is correct,  my analysis says  that
> 'x' must strongly alias with itself (see my attached screenshot)
>
> In the screenshot:
>     -- on the right column is the Jimple statement
>     -- on the left is  a mapping from local 'l' to
> slmaa.instanceKeyString(l,s), where 'l' is the locals in the program, and
> 's'is the statement, smlaa is declared  as  "  LocalMustAliasAnalysis slmaa
> = new StrongLocalMustAliasAnalysis(unitGraph) " ;
>
> Any ideas? Thanks.
> Zell.
>
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-- 
Eric Bodden, Ph.D., http://sse.ec-spride.de/ http://bodden.de/
Head of Secure Software Engineering Group at EC SPRIDE
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