[Soot-list] Re: A possible bug of Jimple generation in Soot

[Chris Pickett]

Me too!

It might be a good idea to have a soot-bugs list, which is read-only, 
and send all bug activity there ... that way interested project members 
can keep an eye on all the comments in bugzilla without needing to go 
through the bugs and choosing which ones to watch.  Unless of course 
this is already an option and I'm just ignorant of it.

Chris

Lin Li wrote:
> Hi Ondrej,
> 
> I think using Bugzilla is a good idea.
> 
> Lin
> 
> 
>>Hi Bin,
>>
>>Thanks for the detailed report.
>>
>>It is a known limitation of the use-original-names option that it
>>generates code that is not exactly like Jimple. In particular, it
>>does not always have the property that values have been split along
>>DU-UD webs, as in Jimple. Therefore, this option may make analyses,
>>including alias analysis, less precise. This is the main reason why
>>this option is not on by default.
>>
>>In some cases, it is not possible to split along DU-UD webs and keep the
>>original names, because the original assignment of names to values is
>>not along DU-UD webs. However, in this case, the relevant local is
>>a stack local, so it seems it shouldn't have a name, so I don't see why
>>Soot does not split it.
>>
>>I've cc'ed this message to the Soot mailing list. Perhaps someone there
>>knows more about the use-original-names option and can explain this.
>>
>>The place to report problems such as this is the
>>Soot mailing list. Note that you must be subscribed to the list in order
>>to post to it. You can subscribe to the list at:
>>http://www.sable.mcgill.ca/mailman/listinfo/soot-list
>>
>>In general, we are no longer using the bug tracker because of system
>>administration issues. To the Soot people reading this: we do now
>>have a Bugzilla set up at https://svn.sable.mcgill.ca/bugzilla, which
>>should solve the issues with the old system. Should we start using and
>>advertising it?
>>
>>Ondrej
>>
>>On Mon, Nov 15, 2004 at 10:23:05PM -0500, Bin Zhao wrote:
>>
>>>   Hi Ondrej,
>>>
>>>       I am Bin Zhao, a first-year graduate student in Computer Science
>>>   Department in University of Maryland. Currently I am using Soot 2.1.0
>>>to
>>>   perform alias analysis for my course project. However, I found there
>>>could
>>>   be possibly a bug in the generated Jimple and caused an incorrect
>>>analysis
>>>   of alias. I tried to report the bug via the "Soot Bug Tracking" link
>>>on
>>>   the Soot Homepage. However the link didn't work any longer. I have
>>>read
>>>   your master thesis and know you are the author of Spark. Therefore I
>>>am
>>>   sending this email to you and you can forward to the appropriate
>>>person.
>>>
>>>       The simple Java program is as the following:
>>>
>>>   import java.util.*;
>>>
>>>   public class ExampleA{
>>>
>>>     public static void main(String[] args){
>>>       List l1 = new ArrayList();
>>>       List l2 = new LinkedList();
>>>       l2 = new ArrayList();
>>>     }
>>>   }
>>>
>>>       We set the use-original-names to true and the generated jimple
>>>file is
>>>   as the following;
>>>
>>>   public class ExampleA extends java.lang.Object
>>>   {
>>>
>>>       public void <init>()
>>>       {
>>>           ExampleA l0;
>>>
>>>           l0 := @this: ExampleA;
>>>           specialinvoke l0.<java.lang.Object: void <init>()>();
>>>           return;
>>>       }
>>>
>>>       public static void main(java.lang.String[])
>>>       {
>>>           java.lang.String[] l0;
>>>           java.util.ArrayList $r0, l1, l2;
>>>           java.util.LinkedList l2, $r2;
>>>
>>>           l0 := @parameter0: java.lang.String[];
>>>           $r0 = new java.util.ArrayList;
>>>           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>           specialinvoke $r0.<java.util.ArrayList: void <init>()>();
>>>           l1 = $r0;
>>>           ^^^^^^^^^
>>>           $r2 = new java.util.LinkedList;
>>>           specialinvoke $r2.<java.util.LinkedList: void <init>()>();
>>>           l2 = $r2;
>>>           $r0 = new java.util.ArrayList;
>>>           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>           specialinvoke $r0.<java.util.ArrayList: void <init>()>();
>>>           l2 = $r0;
>>>           ^^^^^^^^^^
>>>           return;
>>>       }
>>>   }
>>>       You can notice that the generated jimple file uses the same stack
>>>   variable $r0 for both the ArrayList allocations for l1 and l2. And
>>>$r0 is
>>>   assigned to both l1 and l2. When we perform alias analysis, it says
>>>that
>>>   after "l2 = new ArrayList()", l1 and l2 has non-empty intersection of
>>>   points-to set.
>>>
>>>   thanks,
>>>   Bin
>>
>>
>>
>>
>>_______________________________________________
>>Soot-list mailing list
>>Soot-list at sable.mcgill.ca
>>http://www.sable.mcgill.ca/mailman/listinfo/soot-list
>>
>>
> 
> 
> _______________________________________________
> Soot-list mailing list
> Soot-list at sable.mcgill.ca
> http://www.sable.mcgill.ca/mailman/listinfo/soot-list
>