r193934 - Default to use libc++ on OS X 10.9+ and iOS 7+.

[Timur Iskhodzhanov]

ping?

I've spent a fair amount of time debugging this yesterday.

2013-11-05 Nico Weber <thakis at chromium.org>:
> On Tue, Nov 5, 2013 at 9:44 AM, Bob Wilson <bob.wilson at apple.com> wrote:
>>
>> On OS X the libc++ headers are meant to be installed along with clang.  If
>> you check out the libc++ sources in the LLVM projects directory, they should
>> be installed in the right place.
>
>
> Thanks, that makes sense. Should http://clang.llvm.org/get_started.html
> mention checking out libc++, since it sounds that's now a requirement on OS
> X?
>
>>
>>
>> On Nov 5, 2013, at 9:42 AM, Howard Hinnant <hhinnant at apple.com> wrote:
>>
>> > When I use tot clang, (and want libc++), I will forbid clang from
>> > looking the std::headers, and then tell it exactly where the headers are,
>> > e.g.:
>> >
>> > $ clang++ -stdlib=libc++ -std=c++11 -nostdinc++ -I../libcxx/include
>> > test.cpp
>> >
>> > Howard
>> >
>> > On Nov 5, 2013, at 12:35 PM, Nico Weber <thakis at chromium.org> wrote:
>> >
>> >> In addition to the performance issues, libc++ apparently can't be found
>> >> by clang: http://llvm.org/bugs/show_bug.cgi?id=17821
>> >>
>> >>
>> >> On Sat, Nov 2, 2013 at 10:35 PM, Bob Wilson <bob.wilson at apple.com>
>> >> wrote:
>> >> I’m not familiar with those performance issues, so I’m CC’ing Howard in
>> >> case he can provide any details on those issues.  In general, we’re in the
>> >> process of migrating away from libstdc++ on OS X and iOS, so we really do
>> >> want the default to be libc++ regardless of the language mode.  If you have
>> >> particularly performance sensitive code, you can always choose to use
>> >> libstdc++.
>> >>
>> >> On Nov 2, 2013, at 7:05 PM, Nico Weber <thakis at chromium.org> wrote:
>> >>
>> >>> Thanks for upstreaming this!
>> >>>
>> >>> Should this only happen in C++11 mode? libc++ seems to be measurably
>> >>> slower than libstdc++ in C++03 mode (PR17703, PR14554, PR14555).
>> >>>
>> >>>
>> >>> On Sat, Nov 2, 2013 at 4:19 PM, Bob Wilson <bob.wilson at apple.com>
>> >>> wrote:
>> >>> Author: bwilson
>> >>> Date: Sat Nov  2 18:19:53 2013
>> >>> New Revision: 193934
>> >>>
>> >>> URL: http://llvm.org/viewvc/llvm-project?rev=193934&view=rev
>> >>> Log:
>> >>> Default to use libc++ on OS X 10.9+ and iOS 7+.
>> >>>
>> >>> Modified:
>> >>>    cfe/trunk/lib/Driver/ToolChains.cpp
>> >>>    cfe/trunk/test/PCH/cxx-typeid.cpp
>> >>>
>> >>> Modified: cfe/trunk/lib/Driver/ToolChains.cpp
>> >>> URL:
>> >>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains.cpp?rev=193934&r1=193933&r2=193934&view=diff
>> >>>
>> >>> ==============================================================================
>> >>> --- cfe/trunk/lib/Driver/ToolChains.cpp (original)
>> >>> +++ cfe/trunk/lib/Driver/ToolChains.cpp Sat Nov  2 18:19:53 2013
>> >>> @@ -839,6 +839,12 @@ DerivedArgList *Darwin::TranslateArgs(co
>> >>>     }
>> >>>   }
>> >>>
>> >>> +  // Default to use libc++ on OS X 10.9+ and iOS 7+.
>> >>> +  if (((isTargetMacOS() && !isMacosxVersionLT(10, 9)) ||
>> >>> +       (isTargetIPhoneOS() && !isIPhoneOSVersionLT(7, 0))) &&
>> >>> +      !Args.getLastArg(options::OPT_stdlib_EQ))
>> >>> +    DAL->AddJoinedArg(0, Opts.getOption(options::OPT_stdlib_EQ),
>> >>> "libc++");
>> >>> +
>> >>>   // Validate the C++ standard library choice.
>> >>>   CXXStdlibType Type = GetCXXStdlibType(*DAL);
>> >>>   if (Type == ToolChain::CST_Libcxx) {
>> >>>
>> >>> Modified: cfe/trunk/test/PCH/cxx-typeid.cpp
>> >>> URL:
>> >>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/PCH/cxx-typeid.cpp?rev=193934&r1=193933&r2=193934&view=diff
>> >>>
>> >>> ==============================================================================
>> >>> --- cfe/trunk/test/PCH/cxx-typeid.cpp (original)
>> >>> +++ cfe/trunk/test/PCH/cxx-typeid.cpp Sat Nov  2 18:19:53 2013
>> >>> @@ -1,8 +1,8 @@
>> >>> // Test this without pch.
>> >>> -// RUN: %clang_cc1 -include %S/cxx-typeid.h -fsyntax-only -verify %s
>> >>> +// RUN: %clang_cc1 -include %S/cxx-typeid.h -fsyntax-only
>> >>> -stdlib=libstdc++ -verify %s
>> >>>
>> >>> -// RUN: %clang_cc1 -x c++-header -emit-pch -o %t.pch %S/cxx-typeid.h
>> >>> -// RUN: %clang_cc1 -include-pch %t.pch -fsyntax-only -verify %s
>> >>> +// RUN: %clang_cc1 -x c++-header -emit-pch -stdlib=libstdc++ -o
>> >>> %t.pch %S/cxx-typeid.h
>> >>> +// RUN: %clang_cc1 -include-pch %t.pch -fsyntax-only
>> >>> -stdlib=libstdc++ -verify %s
>> >>>
>> >>> // expected-no-diagnostics
>> >>>
>> >>>
>> >>>
>> >>> _______________________________________________
>> >>> cfe-commits mailing list
>> >>> cfe-commits at cs.uiuc.edu
>> >>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>> >>>
>> >>
>> >>
>> >
>>
>
>
> _______________________________________________
> cfe-commits mailing list
> cfe-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>