> On Dec 16, 2014, at 9:32 AM, Dimitry Andric <d...@freebsd.org> wrote: > > On 16 Dec 2014, at 17:15, David Chisnall <thera...@freebsd.org> wrote: >> >> On 16 Dec 2014, at 16:04, Dimitry Andric <d...@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). >> >> That's still potentially an issue if we add local tools that use libclang >> APIs (which we may well do). >> >>> 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. :) >> >> 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. >> >> 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. > > 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... >> >> 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. > > 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… 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
signature.asc
Description: Message signed with OpenPGP using GPGMail
