[Soot-list] FastHierarchy bug

[Tobias Gutzmann]

Hej,

The bugzilla seems to have been down for a while, so I would like to
keep this bugreport alive for the next release. It even comes with a
solution to the problem ;-)

consider the following program:

abstract class BCDE { void foo() { } }
class BCD extends BCDE {
   void foo() { super.foo(); } // line 3
}

calling FastHierarchy.resolveSpecialDispatch() on the invokespecial instruction
generated for the call on line 3 leads to a RuntimeException.
Reason: resolveSpecialDispatch() calls resolveConcreteDispatch(), which then
traverses the class hierarchy. If a superclass is abstract, then an exception is
thrown. However, the code above is valid, so resolving the dispatch shouldn't be
an issue; I think an exception should occur iff the method, not the
class, is abstract. This should probably hold in general, so I think that
resolveConcreteDispatch() has the bug, not resolveSpecialDispatch().

Suggestion: 
- remove lines 468-471 in soot.FastHierarchy
- add code: before returning a result method, check if the method is abstract.
If so, throw an exception.

best regards,
Tobias