[PATCH] CMake: optionaly enable LLVM to be compile with -std=c++11 (default: OFF)

[NAKAMURA Takumi]

We should reject C++11-incompatible compiler in near future.

2013/11/22 Arnaud Allard de Grandmaison <arnaud.adegm at gmail.com>:
> The patch was attempting to mimic autoconf's behaviour...
>
> I am not sure to follow you Eric : do you mean this should not be an option
> any more, and must always be set in autoconf and cmake ? It would then just
> be a question of using the c++1 features (or not). In this case, I believe a
> should at least check that the compiler supports '-std=c++11' (or a
> different wording for non gcc compatible compilers). This would also be the
> right place to check the compiler is a version recent enough as well to
> build llvm --- in accrodance with c++11 switch huge discussion.
>
>
> On Fri, Nov 22, 2013 at 12:26 AM, Eric Christopher <echristo at gmail.com>
> wrote:
>>
>> On Thu, Nov 21, 2013 at 2:25 PM, Meador Inge <meadori at codesourcery.com>
>> wrote:
>> > On 11/21/2013 04:04 PM, Arnaud Allard de Grandmaison wrote:
>> >
>> >> In some cases, like when building llvm+lldb with cmake, llvm has to be
>> >> built in
>> >> c++11 mode. This patch adds the handling of this option. The default is
>> >> OFF for
>> >> now, but I suspect it will move to ON pretty soon given the discussions
>> >> on the
>> >> move to c++11 for the llvm codebase.
>> >
>> > I am not sure why this is any better than -DCMAKE_CXX_FLAGS=-std=c++11,
>> > but
>> > maybe someone else can argue that point.  Also, if/when we switch it
>> > seems like
>> > the option is no longer useful since disabling means LLVM won't build
>> > after
>> > folks start using C++11 features.
>> >
>>
>> *shrug* We can remove the option at that point. I've had one in the
>> autoconf side for the last few years.
>>
>> -eric
>>
>> >> diff --git a/CMakeLists.txt b/CMakeLists.txt
>> >> index f43204f..40cc7b6 100644
>> >> --- a/CMakeLists.txt
>> >> +++ b/CMakeLists.txt
>> >> @@ -179,6 +179,7 @@ else( MSVC )
>> >>    option(LLVM_ENABLE_WARNINGS "Enable compiler warnings." ON)
>> >>  endif()
>> >>
>> >> +option(LLVM_ENABLE_CXX11 "Compile with C++11 enabled." OFF)
>> >
>> > Should this be documented: http://llvm.org/docs/CMake.html ?
>> >
>> >>  option(LLVM_ENABLE_PEDANTIC "Compile with pedantic enabled." ON)
>> >>  option(LLVM_ENABLE_WERROR "Fail and stop if a warning is triggered."
>> >> OFF)
>> >>
>> >> diff --git a/cmake/modules/HandleLLVMOptions.cmake
>> >> b/cmake/modules/HandleLLVMOptions.cmake
>> >> index bb41a58..71a5d25 100644
>> >> --- a/cmake/modules/HandleLLVMOptions.cmake
>> >> +++ b/cmake/modules/HandleLLVMOptions.cmake
>> >> @@ -246,6 +246,10 @@ elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
>> >>    if (LLVM_ENABLE_WERROR)
>> >>      add_llvm_definitions( -Werror )
>> >>    endif (LLVM_ENABLE_WERROR)
>> >> +  if (LLVM_ENABLE_CXX11)
>> >> +    check_cxx_compiler_flag("-Werror -std=c++11" CXX_SUPPORTS_CXX11)
>> >
>> > Why do you need to check for "-Werror" too?
>> >
>> >> +    append_if(CXX_SUPPORTS_CXX11 "-std=c++11" CMAKE_CXX_FLAGS)
>> >> +  endif (LLVM_ENABLE_CXX11)
>> >>  endif( MSVC )
>> >>
>> >>  macro(append_common_sanitizer_flags)
>> >> -- 1.8.3.2
>> >
>> >
>> > --
>> > Meador Inge
>> > CodeSourcery / Mentor Embedded
>> > _______________________________________________
>> > llvm-commits mailing list
>> > llvm-commits at cs.uiuc.edu
>> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
>
>
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