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

[Justin Bogner]

I'm assuming you have libcxx checked out in projects/ of the LLVM
repository.

Is this clang 3.4 or ToT? The cmake build installed the libc++ headers
in a different directory (lib/) than clang looked for them in (include/)
before r194834.

Timur Iskhodzhanov <timurrrr at google.com> writes:
> 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
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
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>>>>>>>> cfe-commits at cs.uiuc.edu
>>>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
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