Date: Tue, 16 Dec 2014 10:39:32 -0700 From: Warner Losh <imp@bsdimp.com> To: Dimitry Andric <dim@FreeBSD.org> Cc: freebsd-toolchain@freebsd.org Subject: Re: Migration to dynamic libs for llvm and clang Message-ID: <4E3A3DA8-209C-43E1-83D4-928823CCBF04@bsdimp.com> In-Reply-To: <F44F2112-59A7-4351-BEED-AB1B17BDA0C4@FreeBSD.org> References: <CAPyFy2DeLiFAW_yS14r1n89r92MFG1sbX88rNgaJshwH9-%2BkQg@mail.gmail.com> <41F09A1C-01D6-42C9-B495-244DFC2B0364@FreeBSD.org> <D359161D-B14C-4F19-8F0D-57FE530D0AF4@FreeBSD.org> <74C51AC7-B7ED-4EBC-8506-1554C7CA31FF@FreeBSD.org> <F44F2112-59A7-4351-BEED-AB1B17BDA0C4@FreeBSD.org>
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--Apple-Mail=_EC97E68D-9267-4AAC-B33D-B0D24C51ADF2 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Dec 16, 2014, at 9:32 AM, Dimitry Andric <dim@FreeBSD.org> wrote: >=20 > On 16 Dec 2014, at 17:15, David Chisnall <theraven@FreeBSD.org> wrote: >>=20 >> On 16 Dec 2014, at 16:04, Dimitry Andric <dim@FreeBSD.org> wrote: >>> This is precisely why the libs should go into /usr/lib/private, so = as to >>> avoid collisions with any upstream libraries installed by e.g. ports = (or >>> when you manually run "make install" after building). >>=20 >> That's still potentially an issue if we add local tools that use = libclang APIs (which we may well do). >>=20 >>> I'm not sure we want to go the 'libbsdfoo.so' route again, as = Baptiste >>> tried this before, and seems to have reversed it again. :) >>=20 >> Upstream doesn't call it libclang (that's the name of the library = with a stable C ABI, which is why I'd like us not to confuse it with = something with a library with an unstable C++ API). They do produce a = libLLVM.so from the LLVM builds and work is underway to have shared = library builds for clang. >>=20 >> libLLVM.so could potentially be in /usr/lib in 11 if we have a = packaged base system, as it would allow us to have different .so = versions installed if things demanded them. The point releases = guarantee backwards ABI compatibility, so we can still upgrade to them = if required. >=20 > Unfortunately we already imported quite a lot of ABI-breaking bug = fixes. > I would prefer only our own tools to be linked against the "FreeBSD" > version of libllvm.so/libwhatever.so. :( >> That said, I agree with the general idea, but one of the first things >>> we should decide is whether this will be optional or not. Having to >>> maintain yet another WITH_CLANG_FOO option is burdensome... >>=20 >> I agree. I'd quite like to see performance numbers for the compiler. = I think I saw about a 10% overhead for buildworld last time I tried, = but that was a couple of years ago. >=20 > There is already a WITH_SHARED_TOOLCHAIN option, that defaults to off, > but I have had it on since approximately the time Kostik added it. I > might just have gotten used to the overhead, if any=E2=80=A6 The 10% figure has been relatively constant over the lifetime of shared libraries in FreeBSD. This is the average hit of using shared libraries and everybody accepts that. I doubt time has changed this much at all. > I would like to do a bit of testing with that, but my TODO list is > rather full at this point, working on the 3.5.0 import. :) We should defer testing until after that import :) Warner --Apple-Mail=_EC97E68D-9267-4AAC-B33D-B0D24C51ADF2 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJUkG5VAAoJEGwc0Sh9sBEA9zQQAKA078Sc8X2VT+C6B7YaLBLT uoYXq66Mg6rSN5QU2dJvKMiak7vgYHBEbi4RvjXGPq+TvC9z74AXeQpn1uwLCfUZ T425jHcihhyguq8/Jk9U7KEnB5zBvb3iyIRfpKJUOt2YVHhKzGkruKmOhm2KgoOm v+/hPHnZJh30nJQldywBpQyrz4RC3zhFM6rn9D9S8LthiHa41zkFU595aWbckUWc f0Id2M8Iwcam264ERsc0hUSZKkvQmHdriGA2M0dTuDcgAGwCYJq01U4R3Iqb/fFS PpD9uPYOTUiT7mfbKe3Jbzm7HCaeONVHTZfSLpU62Hre4y4OiShpHmmvTOepiUN0 evBdJ4L1g7yAraLiRucm+kFdUXFzv0RDMH0f+YAtJRZNSAdgIEVvJvVo3j0FVwfB BDW+xuvhN9+XxE9hgptgy0ch/h1eLurHWb6rdHBQU6wU8IddVOmuegV2FI6aaVxi pMC1dkaY/ZmfyjhxvokIdNxhNhcv10ilG0AIklGm7vl8jW3vJzv2D5LhiPI4UbOh yb/U9oeiFdq249/Lgsr8Vdt0lv+eUZIYkIgIaer8qMlkAU5VSFcODzEmsCPQbheH xJw70riuwqjXHRDZcx8syRXOQkBh3EWA1bSPBouU57h3/w900JyxlmT0qF0PCPLM 51u1HZovittYIJiipSNz =Rdws -----END PGP SIGNATURE----- --Apple-Mail=_EC97E68D-9267-4AAC-B33D-B0D24C51ADF2--
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