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

[Timur Iskhodzhanov]

Please see
http://llvm.org/bugs/show_bug.cgi?id=17821#c7

I don't know what to write in a patch as I can't get a build working for me yet.
That means either
a) something's broken
b) something's not documented well
c) I missed some important how-to announcement regarding building on
10.9 with Xcode 5

2014-02-04 Bob Wilson <bob.wilson at apple.com>:
> Would you like to contribute a patch to clarify that documentation?  I’m not sure what you’re asking for here.
>
> On Feb 4, 2014, at 12:20 PM, Timur Iskhodzhanov <timurrrr at google.com> wrote:
>
>> 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
>>>
>