The documentation for SymTagFuncDebugStart and SymTagFuncDebugEnd state that calling IDiaSymbol::get_lexicalParent will return a symbol for the enclosing function. I interpret this as I will get an IDiaSymbol whose get_symTag method returns SymTagFunction. However, when I do this it returns me the SymTagCompiland and not the function. So the documentation appears wrong, but worse I'm not sure how to actually tie the SymTagFuncDebugStart and SymTagFuncDebugEnd to the containing SymTagFunction.
Does anyone know? A few dumps suggest that SymTagFuncDebugStart and SymTagFuncDebugEnd always come immediately after the corresponding SymTagFunction when enumerating the symbols via IEnumSymbols. Or put another way, that if IDiaSymbol::get_symIndexId returns n for the function, it will return n+1 and n+2 respectively for the func debug start and func debug end.
But I can't be sure this is always true, and this seems unreliable and hackish.
Does anyone have any suggestions on the correct way to do this?
I got this working eventually. The problem is that when you enumerate all the symbols in the global scope using SymTagNull, you will find the FuncDebugStart and FuncDebugEnd symbols. The lexical parent of these symbols is the global scope, because it's the "parent" in the sense that it vended you the pointers to the FuncDebugStart and FuncDebugEnd symbols.
If you get the FuncDebugStart and FuncDebugEnd by calling findChildren on an actual SymTagFunction symbol, however, then its lexical parent will in fact be the original function. So this was an issue of unclear documentation.