read/write sets for a Unit

[Will Benton <willb@cs.wisc.edu>]

Hello,

I'm curious as to what the correct way to access read/write sets for a  
given Unit is from within a BodyTransformer.  I'm assuming that what  
I'm doing is violating some precondition on the SideEffectTester code,  
because it's not working.  (Therefore, the rest of this message, which  
explains what I am doing now, can probably be skimmed or skipped if  
it's clearly wrong.)

Right now, what I'm doing is pretty convoluted (and I'm pretty sure  
that it's wrong -- both a priori and because I get occasional  
ClassCastExceptions from deep within soot code).  My basic approach is  
to override PASideEffectTester with a class that will let me access the  
fields in readSet() and writeSet(), instantiate that class in my  
BodyTransformer and invoke its newMethod method with the Method  
corresponding to the current Body, and then invoking the methods on my  
SideEffectTester-derived class that return the getFields() set from the  
RWSets returned by readSet and writeSet.  I then run soot in  
whole-program mode, enabling spark (my transformation is in the jtp  
pack).

Occasionally, I'll get exceptions like the following.  These occur when  
analyzing method invocations.  It's not clear to me that a particular  
class of method invocations (i.e. special, static, or virtual) is the  
culprit; if I catch these exceptions, I can see that some will fail and  
some will not.  Overall, it appears that between 5-45% of attempts to  
analyze method invocations fail, depending on what program I'm  
analyzing.

Exception in thread "main" java.lang.ClassCastException
        at  
soot.jimple.toolkits.pointer.SideEffectAnalysis.findNTRWSets(SideEffectA 
nalysis.java:44)
        at  
soot.jimple.toolkits.pointer.SideEffectAnalysis.nonTransitiveReadSet(Sid 
eEffectAnalysis.java:57)
        at  
soot.jimple.toolkits.pointer.SideEffectAnalysis.readSet(SideEffectAnalys 
is.java:90)
        at  
soot.jimple.toolkits.pointer.PASideEffectTester.readSet(PASideEffectTest 
er.java:65)
        at  
com.willbenton.sootPasses.wbSideEffectMarker$csssemSideEffectTester.read 
Fields(wbSideEffectMarker.java:13)
        at  
com.willbenton.sootPasses.wbSideEffectMarker.actualTransform(wbSideEffec 
tMarker.java:90)
        at  
com.willbenton.sootPasses.cwsBaseBodyTransformer.internalTransform(cwsBa 
seBodyTransformer.java:32)
        at soot.BodyTransformer.transform(BodyTransformer.java:51)
        at soot.Transform.apply(Transform.java:88)
        at soot.BodyPack.internalApply(BodyPack.java:44)
        at soot.Pack.apply(Pack.java:110)
        at soot.PackManager.runBodyPacks(PackManager.java:423)
        at soot.PackManager.runBodyPacks(PackManager.java:282)
        at soot.PackManager.runPacks(PackManager.java:241)
        at soot.Main.run(Main.java:172)
        at soot.Main.main(Main.java:152)
        at  
com.willbenton.sootPasses.wbSideEffectMarker.main(wbSideEffectMarker.jav 
a:125)

Thanks for any help!




wb

---
Will Benton <willb@cs.wisc.edu>
"Wir sind Bettler, das ist wahr"
   recently updated (11/1/03) contact info at:   
http://www.cs.wisc.edu/~willb/willb.vcf