Re: Handling of main() function for freestanding

[Jakub Jelinek <jakub@redhat.com>]

On Fri, Oct 07, 2022 at 09:51:31AM -0400, Jason Merrill wrote:
> > There are some tests that fail if we do that. For whatever reason,
> > they're checking the current semantics.
> 
> > 	* gcc.dg/c11-noreturn-4.c: Add -fno-builtin-main to options.
> > 	* gcc.dg/inline-10.c: Likewise.
> 
> IMO we still shouldn't emit these pedwarns when freestanding, we shouldn't
> require people to add another flag to avoid them.
> 
> Adding the implicit return 0 unconditionally doesn't mean we also need to
> adopt all the other special treatment of main.
> 
> And I guess we shouldn't implicitly return 0 if the function is declared
> noreturn.
> 
> > 	* gcc.dg/noreturn-4.c: Likewise.
> 
> I'd be inclined to drop this test.

Ok.

> > Arsen implemented Jakub's suggestion which is to add the implicit
> > return by default, but add -fno-builtin-main to restore the previous
> > behaviour. Is that acceptable? If not, can you and Jakub reach
> > consensus so that Arsen knows what to do instead?
> > His -fno-builtin-main patch is at
> > https://gcc.gnu.org/pipermail/gcc-patches/2022-September/602644.html
> > (This is the only one of his patch series not committed, and results
> > in 100s of FAILs for libstdc++ when testing with -fffreestanding).

	Jakub