[Soot-list] What is the difference between getMethod() and getMethodRef()?

[Eric Bodden]

Marc-Andre,

adding to Patrick's explanation, if you know what you are doing you
can use the new option -ire. It should ignore such resolution errors,
producing phantom methods instead.

Eric


On 25 January 2013 23:12, Patrick Lam <plam at sable.mcgill.ca> wrote:
> On 01/25/13 17:03, Marc-Andre Laverdiere-Papineau wrote:
>> Hello,
>>
>> I have been plagued with weird exceptions like this:
>>
>> Exception in thread "main"
>> soot.SootMethodRefImpl$ClassResolutionFailedException: Class
>> javax.servlet.ServletContext doesn't have method getContextPath([]) :
>> java.lang.String; failed to resolve in superclasses and
>> interfacesLooking in javax.servlet.ServletContext which has methods
>> [<javax.servlet.ServletContext: javax.servlet.ServletContext
>> getContext(java.lang.String)>,<javax.servlet.ServletContext: int
>> ...<javax.servlet.ServletContext: javax.servlet.Servlet
>> getServlet(java.lang.String)>,<javax.servlet.ServletContext:
>> java.util.Enumeration getServlets()>,<javax.servlet.ServletContext:
>> java.util.Enumeration getServletNames()>,
>> ...
>> <javax.servlet.ServletContext: void
>> log(java.lang.String,java.lang.Throwable)>,
>> <javax.servlet.ServletContext: java.lang.String
>> getRealPath(java.lang.String)>,<javax.servlet.ServletContext:
>> java.lang.String getServerInfo()>,<javax.servlet.ServletContext:
>> ...<java.lang.Object: void wait()>,<java.lang.Object: void finalize()>,
>> <java.lang.Object: void<clinit>()>]
>>
>>       at soot.SootMethodRefImpl.resolve(SootMethodRefImpl.java:179)
>>       at soot.SootMethodRefImpl.resolve(SootMethodRefImpl.java:105)
>>       at
>> soot.jimple.internal.AbstractInvokeExpr.getMethod(AbstractInvokeExpr.java:54)
>>       at ...
>>
>> It happens if I have something like this:
>> ((DefinitionStmt)u).getInvokeExpr().getMethod()...
>>
>> However, changing it to getMethodRef() won't break - why??? (Sidenote: I
>> am running without exclusions)
>
> Well, if you are just getting the MethodRef, you don't need the method
> to be resolved. It's analogous to requesting a pointer to the method
> without dereferencing it.
>
> Taking a broader view, it seems like you have weirdness in your input
> files where you have references to nonexistent methods. Do you need to
> do anything with all of the methods that you're referencing? If not,
> getMethodRef() should be fine.
>
> pat
>
>
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-- 
Eric Bodden, Ph.D., http://sse.ec-spride.de/ http://bodden.de/
Head of Secure Software Engineering Group at EC SPRIDE
Tel: +49 6151 16-75422    Fax: +49 6151 16-72051
Room 3.2.14, Mornewegstr. 30, 64293 Darmstadt