[Soot-list] dava question

[Eric Bodden]

Hi Dacong.

I am not sure there is a solution to this. The problem is that in
general it's quite impossible to go from monitorenter/exit back to
synchronized blocks. This is one case where de-compilation can fail.
In your case, there are three exitmonitors generated, due to the
exception handling, which complicates things quite a bit.

Eric

On 12 April 2012 00:15, Dacong Yan <tonywinslow1986 at gmail.com> wrote:
> Hi,
>
> I was using dava, and it threw a RuntimeException saying: "Could not
> verify approximated Synchronized body!".
>
> A problem leading to the same exception has been discussed before on
> this list (see:
> http://www.sable.mcgill.ca/pipermail/soot-list/2007-June/001263.html),
> and the conclusion is: it can be resolved by a must-alias analysis or
> copy propagation. But it seems that my code caused some other problem.
>
> The minimum code that can reproduce this problem is attached at the
> very end. I used the options "-p jb.cp only-stack-locals:false -p
> jb.dae only-stack-locals:false" to allow copy propagation, but it
> still fails. Is this a known issue? Or do I need other command line
> options to make it work?
>
> Thanks,
> Tony
>
> --
> Dacong (Tony) Yan
> Ph.D. Student
> Computer Science and Engineering
> The Ohio State University, Columbus
> http://www.cse.ohio-state.edu/~yan
>
>
> Source:
>
> public class Sync {
>  public void f(String s) {
>   synchronized (this) {
>     try {
>       int a = Integer.parseInt(s);
>       if (a == 0) {
>         return;
>       } else {
>         System.out.println();
>       }
>     } catch (Exception e) {
>       throw new RuntimeException();
>     }
>   }
>  }
> }
>
> And the Jimple code for function f (java soot.Main -f J -p jb.cp
> only-stack-locals:false -p jb.dae only-stack-locals:false Sync):
>
>   public void f(java.lang.String)
>   {
>       Sync r0;
>       java.lang.String r1;
>       int i0;
>       java.io.PrintStream $r5;
>       java.lang.Exception $r6;
>       java.lang.RuntimeException $r8;
>       java.lang.Throwable $r9;
>
>       r0 := @this: Sync;
>       r1 := @parameter0: java.lang.String;
>       entermonitor r0;
>
>    label0:
>       i0 = staticinvoke <java.lang.Integer: int
> parseInt(java.lang.String)>(r1);
>       if i0 != 0 goto label3;
>
>    label1:
>       exitmonitor r0;
>
>    label2:
>       return;
>
>    label3:
>       $r5 = <java.lang.System: java.io.PrintStream out>;
>       virtualinvoke $r5.<java.io.PrintStream: void println()>();
>
>    label4:
>       goto label6;
>
>    label5:
>       $r6 := @caughtexception;
>       $r8 = new java.lang.RuntimeException;
>       specialinvoke $r8.<java.lang.RuntimeException: void <init>()>();
>       throw $r8;
>
>    label6:
>       exitmonitor r0;
>
>    label7:
>       goto label11;
>
>    label8:
>       $r9 := @caughtexception;
>
>    label9:
>       exitmonitor r0;
>
>    label10:
>       throw $r9;
>
>    label11:
>       return;
>
>       catch java.lang.Exception from label0 to label1 with label5;
>       catch java.lang.Exception from label3 to label4 with label5;
>       catch java.lang.Throwable from label0 to label2 with label8;
>       catch java.lang.Throwable from label3 to label7 with label8;
>       catch java.lang.Throwable from label9 to label10 with label8;
>   }
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-- 
Eric Bodden, Ph.D., http://bodden.de/
Head of Secure Software Engineering Group at EC SPRIDE
Principal Investigator in Secure Services at CASED
Tel: +49 6151 16-75422    Fax: +49 6151 16-72051
Room 3.2.14, Mornewegstr. 30, 64293 Darmstadt