[Feature]: Investigate varargs parameter in the call graph algorithm

[JonasKlauke]

Missing Feature

The varargs parameter might not be correctly handled in the call graph algorithm.
example:
void m (Object... args)

[JonasKlauke]

Somehow Java does not use array types in invoke expression to MethodHandle::invoke.
It could be caused by the fact that the method is a native method

Bytecode showing that there is no use of an array:

29: invokestatic  #23   // Method java/lang/invoke/MethodHandles.lookup:()Ljava/lang/invoke/MethodHandles$Lookup;
32: aload_2
33: invokevirtual #29  // Method java/lang/Object.getClass:()Ljava/lang/Class;
36: ldc           #35 // String m3
38: ldc           #36  // class b/i2
40: invokestatic  #38 // Method java/lang/invoke/MethodType.methodType:(Ljava/lang/Class;)Ljava/lang/invoke/MethodType;
43: invokevirtual #44  // Method java/lang/invoke/MethodHandles$Lookup.findVirtual:(Ljava/lang/Class;Ljava/lang/String;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/MethodHandle;
46: aload_2
47: invokevirtual #50  // Method java/lang/invoke/MethodHandle.invoke:(Lb/c14;)V

[JonasKlauke]

This is not caused by the native method. This is caused by the usage of the @PolymorphicSignature annotation in Java

[JonasKlauke]

• Add preanalysis in the AbstractCallGraphAlgorithm constructor to set up a list containing all signatures of methods annotated with @PolymorphicSignature.
• Add a method that checks if a given method signature matches this list of methods, ignoring the parameters. The method should return the corresponding SootMethod.
• Use this method in the call graph algorithm's resolveCall method when the actual method target is not found.
• Move the warning in findConcreteMethod to resolveCall, to be triggered only after the method is not found.

[moebarni]

• Add preanalysis in the AbstractCallGraphAlgorithm constructor to set up a list containing all signatures of methods annotated with @PolymorphicSignature.[ ] Add a method that checks if a given method signature matches this list of methods, ignoring the parameters. The method should return the corresponding SootMethod.[x] Use this method in the call graph algorithm's resolveCall method when the actual method target is not found.[ ] Move the warning in findConcreteMethod to resolveCall, to be triggered only after the method is not found.

Point 2:
The matching logic must ignore the parameters and return type.
For example:

@IntrinsicCandidate
    public final native @PolymorphicSignature Object invoke(Object... args) throws Throwable;

Parameters and return type are polymorphic. The return type Object does not reflect the actual return type.

Point 4:
Instead of moving the warning into the implementations of resolveCall, I have moved it into the new findMatchingPolymorphicMethod method.