[Soot-list] null typing passed to useChecker exception

[John Oliver]

Hello.

I am trying to use soot but I am having issues similar to the bug 
https://svn.sable.mcgill.ca/bugzilla/show_bug.cgi?id=109

My test code is as follows:

==============
package test;

import java.util.Arrays;
import java.util.Collection;

public class Loops {

     public void loops() {
         int[] l1 = new int[]{};
         Collection<String> l2 = Arrays.asList();

         for(String o:l2) {
             for(int j:l1) {
             }
         }
     }
}
==============

And I get the following stack trace:

java.lang.Exception: null typing passed to useChecker
     at 
soot.jimple.toolkits.typing.fast.UseChecker.check(UseChecker.java:50)
     at 
soot.jimple.toolkits.typing.fast.TypeResolver.insertCasts(TypeResolver.java:345)
     at 
soot.jimple.toolkits.typing.fast.TypeResolver.inferTypes(TypeResolver.java:124)
     at 
soot.jimple.toolkits.typing.TypeAssigner.internalTransform(TypeAssigner.java:101)
     at soot.BodyTransformer.transform(BodyTransformer.java:51)
     at soot.Transform.apply(Transform.java:104)
     at soot.JimpleBodyPack.applyPhaseOptions(JimpleBodyPack.java:66)
     at soot.JimpleBodyPack.internalApply(JimpleBodyPack.java:89)
     at soot.Pack.apply(Pack.java:124)
     at soot.coffi.CoffiMethodSource.getBody(CoffiMethodSource.java:117)
     at soot.SootMethod.getBodyFromMethodSource(SootMethod.java:82)
     at soot.SootMethod.retrieveActiveBody(SootMethod.java:315)
     at 
soot.jimple.toolkits.callgraph.OnFlyCallGraphBuilder.processNewMethod(OnFlyCallGraphBuilder.java:531)
     at 
soot.jimple.toolkits.callgraph.OnFlyCallGraphBuilder.processReachables(OnFlyCallGraphBuilder.java:426)
     at 
soot.jimple.toolkits.callgraph.CallGraphBuilder.build(CallGraphBuilder.java:84)
     at 
soot.jimple.toolkits.callgraph.CHATransformer.internalTransform(CHATransformer.java:43)
     at soot.SceneTransformer.transform(SceneTransformer.java:39)
     at soot.SceneTransformer.transform(SceneTransformer.java:45)
     at soot.SceneTransformer.transform(SceneTransformer.java:50)


I was wondering if anyone had run into this problem or found any solutions?

I am using jdk 1.6.9_23 and the latest svn for soot.

Having a bit of a dig around, for my example it appears to be a problem 
with soot resolving iterator types when using the original-names. When 
compiled with -g:source,lines,vars, the compiled class seem to associate 
the name i$ to the iterator of the loops. For the first loop i$ is an 
java.util.Iterator for the second loop it is an int that is being use as 
an array index.

============
Output from javap -l :

   LocalVariableTable:
    Start  Length  Slot  Name   Signature
    64      0      8    j       I
    42      28      5    arr$       [I
    47      23      6    len$       I
    50      20      7    i$       I
    39      31      4    o       Ljava/lang/String;
    19      54      3    i$       Ljava/util/Iterator;
    0      74      0    this       Ltest/Loops;
    4      70      1    l1       [I
    12      62      2    l2       Ljava/util/Collection;

===========

getLocalForIndex in soot.coffi.Util then seems to mistakenly label them 
as the same JimpleLocal due to them having the same name. This method 
contains a comment "Feng asks: why this is necessary? it does wrong 
thing for searching local variable names. It is going to be verified 
with plam.", does anyone know if this is the issue he is referring to?

If use-original-names is set to false then getLocalForIndex simply 
assigns a name and everything works fine.

Does anyone have any solution to this? Unfortunately I have failed at 
fixing the problem and my alternative solution is to allow names to be 
generated then maintain a separate map mapping from the Local to the 
actual variable name. This however does seem like a bit of a hack and 
thought I would ask to see if anyone else had any ideas.

Thanks for any help you can give.

John Oliver