[Soot-list] Re: Global variables in soot

[John Chaitanya Kati]

by expressions i mean those involving two operands like a*b, a+b etc...


On Fri, 4 May 2007, Eric Bodden wrote:

> So in your example, would it ot suffice to say that...
>
> $i2 = <Test: int a>;
>
> ... here the expression "<Test: int a>" is available in $i2?
>
> So whenever a field reference is assigned to a local, it's expression
> is available in that local.
>
> Eric
>
> On 04/05/07, John Chaitanya Kati <johnkati at cse.iitb.ac.in> wrote:
>> 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...
>
>
>

-- 

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