[cxx-abi-dev] Passing an empty class by value

[Marc Glisse]

On Fri, 11 Dec 2015, Nelson, Clark wrote:

> It has come to my attention that GCC and clang generate incompatible code
> for passing an argument of an empty class type.
>
> clang seems to completely ignore arguments and parameters of empty class
> type -- which seems to make a certain amount of sense.
>
> OTOH, as far as I understand it, GCC effectively treats an empty class
> equivalently to a class containing a single member with some character
> type -- which also seems pretty reasonable.
>
> Should the C++ ABI come down on one side or the other of this question?

See A-5 in https://mentorembedded.github.io/cxx-abi/cxx-closed.html for 
some historical discussion.

> This is really the sort of question a psABI should settle. But of course
> the C language doesn't actually support a structure with no members, so
> it's not too surprising if a psABI doesn't nail down what should happen
> for this.

Last time I raised this, psABI was also suggested:
http://sourcerytools.com/pipermail/cxx-abi-dev/2013-November/002627.html

-- 
Marc Glisse