https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97644
--- Comment #11 from Iain Buclaw <ibuclaw at gdcproject dot org> --- (In reply to Jan Hubicka from comment #10) > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97644 > > > > --- Comment #9 from Iain Buclaw <ibuclaw at gdcproject dot org> --- > > (In reply to Jan Hubicka from comment #8) > > > > Current workaround I'm using locally for the time being is to call > > > > thunk_info::process_early_thunks if the particular branch where this ICE > > > > happens is hit. > > > > > > Why D frontend needs to expand the thunk early and does not rely on > > > backend to handle it same way as C++ does? It would be most practical > > > if both was finalizing same way. > > > > > > If there is good reason for not doing so and there is no PCH in D > > > frontend we could just add argument to expand_thunk to avoid the game o > > > putting things into a vector. > > > > > > > Not discounting that I may be doing it wrong. The call to expand_thunk is > > there so that thunks for externally defined methods are generated. > > > > As the backend usually doesn't emit such thunks, a gimple generated thunk is > > forced by the frontend. > > > > I have seen linker errors in the past when this was not done, however there > > could be some alignment with what C++ does to handle this though. > > Aha, thanks for explanation. > In C++ thunks was always connected to the actual function so for > external symbols we indeed do not produce the thunk. > > How does the symbols look like? So you have external symbol and a thunk > associated to it with different visibility? What it is? Because this is what the reference D compiler does, thunks are static (in the C sense) and connected with the class definition, where it is referenced by the class vtable symbol. However, I have for the past week been trialling out thunks that are global and emitted only if the function has a definition as well as per what you described about C++ thunks. The only drawback I've found so far is that thunks for extern(C++) classes are left undefined, however I can resolve this by implementing mangle support in the D front-end so that the C++ generated thunks can be referenced directly.
