Date: Mon, 17 Feb 2020 14:12:31 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Dewayne Geraghty <dewayne.geraghty@heuristicsystems.com.au> Cc: freebsd-hackers@freebsd.org Subject: Re: Why is not llvm-config executable included? Message-ID: <20200217121231.GB29554@kib.kiev.ua> In-Reply-To: <0f258cc4-7aae-b757-add0-e44c329c8255@heuristicsystems.com.au> References: <D1A947BC-BCD9-4BAE-9D1B-EB1B433C1452@FreeBSD.org> <20200215185821.GV4808@kib.kiev.ua> <0f258cc4-7aae-b757-add0-e44c329c8255@heuristicsystems.com.au>
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On Mon, Feb 17, 2020 at 09:03:49AM +1100, Dewayne Geraghty wrote:
> On 16/02/2020 9:27 am, Konstantin Belousov wrote:
> > One of the reason why llvm in base should not be used as llvm infrastructure
> > is because llvm API and ABI is not stable across llvm releases, and exposing
> > that would make compiler updates in stable impossible due to the stable
> > branches guarantee of ABI stability.
>
> I think you're saying - don't build ports in a base (without the llvm
> port), rather use a separate build jail with llvm port.
I am not saying anything even close to that.
I am claiming that libraries built as part of the /usr/bin/cc build
in base should not be used for any other purposes. It is not trivial
to use them, because they are not installed. Which is good for the
reasons I explained in my first response.
It might be that installing these libs in private manner would be useful
because
tom% ls -li /usr/bin/{cc,ld.lld,lldb} ~
241736 -r-xr-xr-x 6 root wheel 66188728 28 янв. 13:21 /usr/bin/cc
241866 -r-xr-xr-x 1 root wheel 39837056 28 янв. 13:21 /usr/bin/ld.lld
241987 -r-xr-xr-x 1 root wheel 64386992 28 янв. 13:21 /usr/bin/lldb
i.e. we might save around 100MB from the base install. But even if
this is done, the libs are still strictly for base /usr/bin/cc.
>
> We used to build all ports in base and ship them to clients. Around
> FreeBSD6 we started to build within a jailed environment, as we
> supported i386 & amd64; something we still do. Though I'm concerned
> that perhaps we should migrate (our jails) back to using gcc where-ever
> possible, in the hope of avoiding future ABI incompatibility?
>
> In my experience replacing a base 'something' with the port of
> 'something' must be done carefully. (our experience with
> binutils and libressl, ultimately required removing all base "stuff" and
> using workarounds like softlinks - a bit messy, but scriptable)
>
> Would using gcc, in the build jail, provide better insurance against ABI
> breakage?
I do not see how using gcc instead of clang would change anything regarding
ABI. Also what ABI breakage are you talking about there ?
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