Provide a List of Call Sites That is Free of Synthetic Builtin Functions

[utkonos]

What is the feature you'd like to have?
Add a new function property which returns a list of call sites that excludes any function in .synthetic_builtins.

Is your feature request related to a problem?
I have to add code to exclude these synthetic functions from my list of call sites. The only way this can be done is to have one of the ILs that includes the synthetics generated and then to traverse it to exclude synthetics. This is not ideal. I looked at the Python source for binaryninja.function and the list of call sites comes from core.BNGetFunctionCallSites(self.handle, count). It seems like the most optimal place to fix this is to add a flag/parameter to this call that excludes synthetics, but you all can determine the best fix. It probably should happen over the C++ border not in Python.

Are any alternative solutions acceptable?
I have a slow, in Python, cleaner function that traverses IL and excludes synthetics.

[utkonos]

I don't know if this is a good idea for an alternative, but the ReferenceSource objects that are returned by function.call_sites could have a boolean attribute that can be set to True or False depending on whether there is a synthetic call at the location.

https://api.binary.ninja/binaryninja.binaryview-module.html#binaryninja.binaryview.ReferenceSource

[utkonos]

This is my very ugly workaround:

synthetic_builtins = bv.get_section_by_name('.synthetic_builtins')
for f in bv.functions:
    if synthetic_builtins:
        call_sites = list()
        for cs in f.call_sites:
            if not hasattr(cs.mlil, 'dest'):
                call_sites.append(cs)
                continue
            if not hasattr(cs.mlil.dest, 'value'):
                call_sites.append(cs)
                continue
            if synthetic_builtins in bv.get_sections_at(cs.mlil.dest.value.value):
                continue
            call_sites.append(cs)
    else:
        call_sites = f.call_sites

[utkonos]

This workaround is much less of a kludge:

from binaryninja.commonil import Call
for f in bv.functions:
    call_sites = list()
    for cs in f.call_sites:
        if isinstance(cs.llil, Call):
            call_sites.append(cs)

But making a blacklist first is by far the fastest (night and day fast):

s = bv.get_section_by_name('.synthetic_builtins')
synthetic_builtins = [syb[0].address for syb in bv.symbols.values() if syb[0].address >= s.start and syb[0].address <= s.end]
blacklist = {r.address for x in synthetic_builtins for r in bv.get_code_refs(x)}
for f in bv.functions:
    call_sites = list()
    for cs in f.call_sites:
        if cs.address in blacklist:
            continue
        call_sites.append(cs)

[psifertex]

The only reason I don't like adding it to referencesource is that referencesource can be used for other things that aren't necessarily calls so I'm not sure it makes sense there. Otherwise it would be a clean solution.