Call Graph with Edges for Callbacks from Libraries

[moshethebeadle]

I tried creating a call graph using the class hierarchy algorithm. It did fine, except for code like this:

class C {
      Map<Long, String> mapLongsToStrings(List<Long> longs) {
        return longs
            .stream()
            .collect(
                Collectors.toMap(
                    Function.identity(),
                    this::longToString
                )
            );
    }

    String longToString(Long l) {
       return l.toString();
    }
}

Obviously, this is a simple version, but it was unable to create the edge from mapLongsToStrings to longToString.

My IDE can handle this just fine when I do Call Hierarchy, and I believe other analysis tools can as well.

Do I need to change my analysis options in order to make the algorithm add the missing edge?
(Note: I did not add the Java core library to the analysis because it took a long time).

I believe the core issue is that SootUp needs to model the library (Collectors.toMap) to be able to automatically add the edge. But I'm rather unfamiliar in this area.

[JonasKlauke]

Yeah you are correct, this is an indirect edge which is currently not modeled in SootUp.
It is indirect, because technically ToMap calls the longToString method.
This could be added as an implicite edge in the call graph algorithm.
Currently SootUp only adds clinit calls in the implicite edge step.
You could add your requested behaivor here

SootUp/sootup.callgraph/src/main/java/sootup/callgraph/AbstractCallGraphAlgorithm.java

Line 248 in ec86625

protected void resolveAllImplicitCallsFromSourceMethod(

[Liyw979]

Hi @JonasKlauke, implicit calls are really difficult to deal with. Is there any plan on this?