https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91356
--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> --- (In reply to Niels Möller from comment #2) > (In reply to Jonathan Wakely from comment #1) > > The ABI dictates the calling conventions and there's certainly nothing that > > libstdc++ can do about it. > > My impression was that C++ ABI is under the control of compiler and C++ > standard library, and that there is no such thing as a standard C++ ABI. Most compilers (not all, in particular not Microsoft) use the strangely named Itanium C++ ABI. > As evidenced by the (rare) ABI breaks in libstdc++, and the difficulty of > linking C++ objects compiled with different C++ compilers (e.g, g++ and > clang++). It is an ABI for the language, not the library. g++ and clang++ are supposed to be compatible, as long as you use the same standard library for both. > So if > it's really not feasible to improve the situation at all for gnu/linux > x86_64 elf targets, *please* try to keep std::unique_ptr in mind when > involved in ABI design for other targets. There are indeed sometimes discussions about a V2 of the ABI, for new targets or those that can afford to break ABI compatibility. > For specific types defined by the GNU standard C++ library, it may also be > possible to add any needed G++ specific attributes in library headers to > tell the compiler to depart from the "standard" ABI. clang has such an attribute [[clang::trivial_abi]], p1029 is trying to standardize it. But adding it in the library now would be an ABI break, which the maintainers are strongly opposed to :-( > In my experience (mainly from working on the webrtc.org code, where > implementation inheritance is discouraged), it's common with implementations > of interface classes consisting of almost trivial implementations of the > interface's virtual functions, which only setup the correct arguments for > calling a non-inlined (and possibly virtual) method on some member to do the > real work. virtual doesn't always prevent inlining (but it often does indeed).
