Re: toolchain/54463: FORTIFY_SOURCE won't work with clang.

[Pedro Giffuni <pfg%FreeBSD.org@localhost>]

On 17/08/2019 13:20, Joerg Sonnenberger wrote:
> The following reply was made to PR toolchain/54463; it has been noted by GNATS.
>
> From: Joerg Sonnenberger <joerg%bec.de@localhost>
> To: gnats-bugs%netbsd.org@localhost
> Cc: toolchain-manager%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
> 	netbsd-bugs%netbsd.org@localhost
> Subject: Re: toolchain/54463: FORTIFY_SOURCE won't work with clang.
> Date: Sat, 17 Aug 2019 20:04:12 +0200
>
>   On Wed, Aug 14, 2019 at 01:20:00AM +0000, pfg%FreeBSD.org@localhost wrote:
>   > However, clang does behave very different from GCC and can't really support FORTIFY_SOURCE.
>   
>   Well, we have various tests in the test suite and I know that they work
>   with clang. I'm therefore a bit puzzled by this report, especially since
>   it doesn't actually contain anything actionable.
>   

Hmm ... even more puzzling, FreeBSD has the same tests but we don't 
support FORTIFY_SOURCE at all, so at this time I have no idea what we 
are testing :-/.

I found an old posting (2015), that explains the problem:

http://lists.llvm.org/pipermail/cfe-dev/2015-November/045846.html

It may be that __builtin_object_size got fixed in recent versions of 
clang, but there are surely differences to account for, like the lack of 
__builtin_va_arg_*.

Perhaps NetBSD's FORTIFY_SOURCE ignores any compiler like clang that 
reports itself as old as GCC 4.2. In that case perhaps its best to just 
close the PR.

Pedro.