[Soot-list] Re: Global variables in soot

[John Chaitanya Kati]

Hi,
    I am trying to implement inter-procedural available expression 
analysis using call string approach. As far as i know, i have to take care 
of expressions which have only one or both operands as global and create a 
bitvector of only those expressions. If both variables in the expression 
are local then i need not care for such type of expressions. But its 
getting difficult for me now...





On Fri, 4 May 2007, Eric Bodden wrote:

> Hi again.
>
> Sorry but I overlooked something. As Patrick just reminded me,
> points-to analysis only works for reference types, while the field in
> your example is an int. So it seems like you would have to write your
> own analysis for this.
>
> What are you actually trying to achieve?
>
> Eric
>
> On 04/05/07, Eric Bodden <eric.bodden at mail.mcgill.ca> wrote:
>> Ah, I see.
>> 
>> In this case, I think you need points-to analysis. You want to find
>> out which values $i2 could possibly point to. We have some tutorials
>> and papers about how to use points-to analysis in Soot online.
>> 
>> Eric
>> 
>> On 04/05/07, John Chaitanya Kati <johnkati at cse.iitb.ac.in> wrote:
>> > for my below program, jimple is giving the following output
>> >         int i0, i1, $i2, $i3;
>> >          $i2 = <Test: int a>;
>> >          i1 = $i2 * i0;
>> >
>> > so its treating $i2 as local since its getting declared. But actually it
>> > represents variable 'a' which is global. I need this information for
>> > interprocedural available expression analysis. So how do i resolve it ?
>> >
>> >
>> >
>> >
>> > On Fri, 4 May 2007, Eric Bodden wrote:
>> >
>> > > Ok, so what you mean by global variables are actually fields. it's as
>> > > I said: local variables are represented by soot.Local's and
>> > > fields/global variables by soot.jimple.FieldRef's.
>> > >
>> > > Eric
>> > >
>> > > On 04/05/07, John Chaitanya Kati <johnkati at cse.iitb.ac.in> wrote:
>> > >> By global variables i meant, which are available to all the methods of 
>> the
>> > >> class.
>> > >> class Test
>> > >> {       static public int a=5;
>> > >>         static public void main(String args[])
>> > >>         {
>> > >>                 int b=10,c;
>> > >>                 c = a*b;
>> > >>                 add(a,b);
>> > >>         }
>> > >>         static void add(int i, int j)
>> > >>         {
>> > >>                 i=i+j;
>> > >>                 a=15;
>> > >>         }
>> > >> }
>> > >> a is global, b,c are local to main. I want to find out such variables.
>> > >>
>> > >>
>> > >>
>> > >>
>> > >>
>> > >>
>> > >>
>> > >>
>> > >>
>> > >>
>> > >>
>> > >> On Fri, 4 May 2007, Eric Bodden wrote:
>> > >>
>> > >> > What's a global variable?
>> > >> >
>> > >> > Soot knows variables of type soot.Local. Those are obviously local.
>> > >> > Then there also are field references, which are obviously field
>> > >> > references. Are those what you mean by global? (Of course, a local 
>> can
>> > >> > well be assigned a field reference, the same way as it can happen in
>> > >> > Java code.)
>> > >> >
>> > >> > Eric
>> > >> >
>> > >> > On 04/05/07, John Chaitanya Kati <johnkati at cse.iitb.ac.in> wrote:
>> > >> >> Hi,
>> > >> >>    Is there a way to find out if a variable is global or not in 
>> soot ?
>> > >> >>
>> > >> >> --
>> > >> >> Thanks for any help in advance
>> > >> >> John Chaitanya
>> > >> >>
>> > >> >
>> > >> >
>> > >> >
>> > >>
>> > >> --
>> > >>
>> > >> Thanks
>> > >> John Chaitanya
>> > >> Like a rose trampled on the ground, you took the fall and thought of 
>> me...
>> > >>
>> > >
>> > >
>> > >
>> >
>> > --
>> >
>> > Thanks
>> > John Chaitanya
>> > Like a rose trampled on the ground, you took the fall and thought of 
>> me...
>> >
>> 
>> 
>> --
>> Eric Bodden
>> Sable Research Group
>> McGill University, Montréal, Canada
>> 
>
>
>

-- 

Thanks
John Chaitanya
Like a rose trampled on the ground, you took the fall and thought of me...