aaron.ballman added a comment. In D122874#3422489 <https://reviews.llvm.org/D122874#3422489>, @philnik wrote:
> In D122874#3422263 <https://reviews.llvm.org/D122874#3422263>, @aaron.ballman > wrote: > >> I'm not opposed, but this does muddy the waters about the target-specific >> nature of the attribute. Currently, the semantic attribute cannot be used >> outside of Itanium ABI targets, so it doesn't work on Windows (and we don't >> want it to -- Microsoft hasn't picked their ABI for the standard attribute >> and we want to avoid ABI breaks). But should we pick an ABI for the GNU >> attribute on Windows and just assume that Microsoft gets no say in the ABI >> for that because it's not their vendor extension? Or, if we disallow the GNU >> spelling on Windows because we want it to match the ABI of the standard >> attribute, does it actually help libc++ to expose the GNU spelling? >> >> Also, the change is missing test coverage and a release note. > > The best option for libc++ would probably be having the same ABI for > `__atrribute__((no_unique_address))` and `[[msvc::no_unique_address]]` on > Windows. And if `[[msvc::no_unique_address]]` and `[[no_unique_address]]` (when eventually implemented) in MSVC have a different ABI impact, will we will leave `__attribute__((no_unique_address))` alone so it won't break ABI? > We already have code that uses > `[[no_unique_address]]`/`[[msvc::no_unique_address]]` but clang-cl currently > supports none of them, so there will be an ABI break if we declare these > things stable before clang-cl has implemented one of these (although we don't > //really// care about ABI stability on Windows AFAICT). I believe we care about ABI stability, even on Windows. At the very least, I've never heard that the community does not care about ABI stability on Windows. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D122874/new/ https://reviews.llvm.org/D122874 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
