Clean up vtable helper documentation

src/smgdc/vtable.py

@@ -24,6 +24,7 @@ itanium_demangler._is_ctor_or_dtor = itanium_demangler.is_ctor_or_dtor
 
 
 def reorder_vfns_windows_estimate(symbols: list[Symbol], start_pos) -> list[Symbol]:
+    # reorders a given subclass-level slice of linux symbols to reflect windows ordering
     name_buckets = collections.defaultdict(list)
     for n, symbol in enumerate(symbols):
         # collect overrides into buckets based on function name
@@ -31,13 +32,13 @@ def reorder_vfns_windows_estimate(symbols: list[Symbol], start_pos) -> list[Symb
         if dmsym:
             name_buckets[dh.extract_method_fname(dmsym)].append(symbol)
         else:
-            # hack for __cxa_pure_virtual
+            # HACK: preserves positions of references to __cxa_pure_virtual
             name_buckets[(dmsym, n)].append(symbol)
 
     output_symbols: list[Symbol] = []
     for fname, syms in name_buckets.items():
         # on windows, overloads are made consecutive and in reverse of declared order
-        # iteration order is guaranteed as of 3.7+ to be the insertion order,
+        # iteration order is guaranteed as of py3.7+ to be the insertion order,
         # so this should output symbols otherwise in their original order
         output_symbols.extend(reversed(syms))
 
@@ -75,12 +76,14 @@ def get_windows_vtables_from(
             # filter MI thunks
             dmsym = itanium_demangler.parse(sym.name)
             if dmsym:
-                # __cxa_pure_virtual hits this
                 if (
                     not itanium_demangler.is_ctor_or_dtor(dmsym)
                     and dh.extract_method_signature(dmsym) in thunk_fns
                 ):
                     continue
+            else:
+                # __cxa_pure_virtual returns None here; we still add it to the vtable slice
+                pass
             class_vfns.append(sym)
         vt_out.extend(reorder_vfns_windows_estimate(class_vfns, vt_low))