https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96283
--- Comment #2 from Eyal Rozenberg <eyalroz at technion dot ac.il> --- (In reply to Andrew Pinski from comment #1) > (In reply to Eyal Rozenberg from comment #0) > > I'm assuming the compiler provides the linker with enough information to > > realize which virtual methods' implementations are missing > > It does not. Ok, still - the linker knows which virtual methods it needs, and it knows which are provided by each compiled translation unit. Isn't that enough? > Also techinically the C++ ABI can really be changed. I don't understand how this sentence relates to the previous part of your reply. If you mean - can change between compilation and linking - that's theoretically possible but would be the cause of all sorts of trouble.