On Fri, Oct 30, 2009 at 3:59 PM, Antoine Labour <pi...@google.com> wrote:
> > > On Fri, Oct 30, 2009 at 3:54 PM, Jeremy Orlow <jor...@chromium.org> wrote: > >> On Fri, Oct 30, 2009 at 3:46 PM, Scott Hess <sh...@chromium.org> wrote: >> >>> Just to be clear for those of us who are wobbly on C++, this is >>> because during the constructor or destructor, your object is of the >>> class in question, NOT of the class it will finally be, because in the >>> constructor the subclass has not been constructed, yet, and in the >>> destructor the subclass was already destructed. So calling to the >>> subclass virtual implementation would be bad. >>> >>> Scott Meyers says: http://www.artima.com/cppsource/nevercall.html >>> >>> Is there any way we could modify an object to assert that it can't >>> happen in development? Like scoped_vtable_killer declared in the >>> constructor and destructor which makes calling a virtual method on >>> that object fatal? >>> >> >> Or is there any sort of built in compiler warning that we could turn on? >> I did a bit of searching and was really surprised that I couldn't find any >> mention of such a thing. >> > > The compiler could find if it's called directly from the destructor, but > there's no way it'd find your case ! The virtual call happens on another > thread. > > To Scott's question: you can blit NULL into the vtable field, if you know > where it is (it's not too hard, but depends on the compiler). You'll know if > you call it - you'll die. > For the original issue this doesn't work b/c for virtual calls in the constructor/destructor, the compiler may optimize them to be non-virtual. Also, it looks like this keeps biting chromium: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33475 Better yet, you could have a static table of functions that print a message > before dying and blit that one, but that gets trickier. > > Antoine > > --~--~---------~--~----~------------~-------~--~----~ Chromium Developers mailing list: chromium-dev@googlegroups.com View archives, change email options, or unsubscribe: http://groups.google.com/group/chromium-dev -~----------~----~----~----~------~----~------~--~---
