[libcxx-dev] unstable ABI compiler assumptions

[Richard Smith via libcxx-dev]

Hi,

In https://reviews.llvm.org/D63744 I'm proposing a change to libc++ that
(unless we add an additional configuration flag) would mean that the
unstable ABI is not necessarily ABI-compatible with itself across different
compilers (in particular, one that supports a particular C++ attribute and
one that does not), nor between C++ language modes that support that
attribute and those that don't (which in both Clang and GCC is C++98/03
versus everything else).

Do we think that's acceptable? Specifically:

 * Do users of the unstable ABI need it to be ABI-compatible across
compiler versions and across compilers?
 * Do users of the unstable ABI need it to be ABI-compatible across C++
language modes (in particular, C++98 versus everything else)?

And (deep breath) would version-locking the unstable ABI to the
corresponding version of Clang be acceptable?

Thanks!
Richard
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/libcxx-dev/attachments/20190624/898fa1ee/attachment.html>