On Tue, Jun 23, 2015 at 12:18:30PM +0200, Marek Polacek wrote:
> > Is it intended that programs be able to take the address of
> > the builtins that correspond to libc functions and make calls
> > to the underlying libc functions via such pointers? (If so,
> > the patch will need some tweaking.)
>
> I don't think so, at least clang doesn't allow e.g.
> size_t (*fp) (const char *) = __builtin_strlen;
Well, clang is irrelevant here, __builtin_strlen etc. is a GNU
extension, so it matters what we decide about it. As this used to work
for decades (if the builtin function has a libc fallback), suddenly
rejecting it could break various programs that e.g. just
#define strlen __builtin_strlen
or similar. Can't we really reject it just for the functions
that don't have a unique fallback?
Jakub
