added reset methods to Scene and SourceLocator to load multiple sources into one Scene and Concrete Native Methods

[lukaswd]

These two methods allow for subsequent calls of loadNecessaryClasses().

With that it is possible, if the two methods are called before the next loadNecessaryClasses() method call, to load multiple sources into the same Soot Scene.

Example code to load two programs into the same Soot Scene:

// Options setting for the first source here

Scene.v().loadNecessaryClasses();

// Options setting for the second source here

SourceLocator.v().resetCaches();
Scene.v().resetSootClassPathCache();
Scene.v().setResolving(false);

Scene.v().loadNecessaryClasses();

[StevenArzt]

We should only use this semantics if the native code module is enabled. Maybe we can add a flag to the Options to enable or disable native code and check this flag here. Keep in mind that the options are generated from XML files via XSLT, so don't modify the Java file directly.

@MarcMil What do you think?

[MarcMil]

Sounds like a good idea, this implementation right here would brick things.

I wonder whether it would be better to do something like hasActiveBody() || ms != null, so if it is possible to retrieve a body at all, which is what every caller seems to actually want to know.

[StevenArzt]

That would be an option, but it would also force us to refactor the Jimple Native reader to make it a proper MethodSource.

[StevenArzt]

@lukaswd The code style check failed. Please have a look and fix the code accordingly.