[Soot-list] questions about soot.jimple.toolkits.infoflow package

[jiangfan shi]

Hi, Richard,

I looked through soot.jimple.toolkits.infoflow package. There are 14
classes in this package. I wonder if I can classify them as following:

1. infoFlowAnalysis
ClassInfoFlowAnalysis 	
InfoFlowAnalysis
SimpleMethodInfoFlowAnalysis 	
SmartMethodInfoFlowAnalysis 	

2. objectAnalysis
ClassLocalObjectsAnalysis
LocalObjectsAnalysis 	
SimpleMethodLocalObjectsAnalysis 	
SmartMethodLocalObjectsAnalysis

3. supportive classes

AbstractDataSource 	
CachedEquivalentValue 	
CallChain 	
CallLocalityContext 	
FakeJimpleLocal 	
	
Then I have several understandings which maybe related to concepts of
infoFlowAnalysis and the code of infoFlowAnalysis.  If you find
anything wrong, could you please correct me there? thanks.

1. About the data flow graph

   From looking at code, the data flow graph is not a call-graph, and
it is a complete graph for a class.  Every node is a global static
field, parameter of a method or class field.

2. About the flow summary for each method

Each entry in a flow summary records which static field, class field
or method parameter is used inside the method. If I understand this
correctly, the scope of the information flow analysis is only for a
class and not for inter-classes. For example, there is a situation
where a variable is defined in a method m1 in the class A, and it is
passed as a parameter for a method m2 in the class B. We only consider
m1 and m2 separately. When we consider m1 or m2, we only records which
method parameter is used inside the method, and we do not consider
further which variable is passed to the parameter.

3. About running the code

I wrote down following piece of code to run the infoFlowAnalysis. Is
this roughly correct? Anyway I am going to run and see what happened.
	
package mytransformer;
import soot.*;
import java.util.*;
import soot.jimple.toolkits.callgraph.*;
import soot.jimple.toolkits.infoflow.*;

public class myInfoFlowAnalysis extends SceneTransformer {
	public static void main(String[] args) {
		if (args.length == 0)
			System.exit(-1);
		PackManager.v().getPack("wjtp").add(
				new Transform("wjtp.mytransform", myInfoFlowAnalysis.v()));
		soot.Main.main(args);
	}

	private static myInfoFlowAnalysis instance = null;

	public static myInfoFlowAnalysis v() {
		if (instance == null)
			return (instance = new myInfoFlowAnalysis());
		return instance;
	}

	protected void internalTransform(String phaseName, Map options) {
		InfoFlowAnalysis ifa= new InfoFlowAnalysis(false,false);
		
		CallGraph cg = Scene.v().getCallGraph();
		// Find every application  class
		List heads = new LinkedList();
		Iterator getClassesIt = Scene.v().getApplicationClasses().iterator();
		while (getClassesIt.hasNext()) {
			SootClass appClass = (SootClass) getClassesIt.next();
			//is this enough to begin a infoAnalysis?
			ClassInfoFlowAnalysis 	cifa= new ClassInfoFlowAnalysis(appClass,ifa);
		}
	}
}

Thanks in advance.

Jiangfan


> Also, I wrote the soot.jimple.toolkits.infoflow package which tracks
> explicit information flow (flow via assignments, but not via control
> decisions).  The package is not very user friendly.

You would have to
> invoke it manually by constructing an InfoFlowAnalysis object (no command
> line option).

It works by generating a whole-program data flow graph (using
> a very conservative approximation for flow occuring within the class
> library).

The analysis will then provide you with flow summaries for each
> method that describe what method parameters, class fields, and static fields
> flow to each other or to the method's return value.

There are some
> granularity options for the results, and also the option to include or
> exclude primitive data flow (ie, you can do just objects if you want).
>
> -Richard
>
> On Tue, Aug 12, 2008 at 8:25 AM, jiangfan shi <jiangfan.shi at gmail.com>
> wrote:
>>
>> Hi, All,
>>
>> I am doing a project requiring a inter-procedure data dependency
>> analysis (def-use). Before I dig into the coding by myself for the
>> task, I wonder if  there are some available data-flow analysis  or
>> similar analysis in Soot?
>>
>> Thanks in advance.
>>
>> Jiangfan
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>
>