[LLVMdev] CMake, compiler-rt, and MacOS

[Alexey Samsonov]

On Tue, Feb 5, 2013 at 12:38 PM, Kostya Serebryany <kcc at google.com> wrote:

> +samsonov, glider
>
>
> On Tue, Feb 5, 2013 at 12:16 PM, Chandler Carruth <chandlerc at google.com>wrote:
>
>> On Mon, Feb 4, 2013 at 6:21 AM, Erik Verbruggen <erik.verbruggen at me.com>wrote:
>>
>>> Hi Chandler,
>>>
>>> If I remember correctly, you are the de-facto maintainer for the
>>> CMake-built-mainainer, so..:
>>>
>>
>> Sure, but I'm often busy. You're better off using the development mailing
>> list for questions such as this, and I've moved the conversation there.
>>
>>
>>> I have a problem compiling compiler-rt on MacOS with libc++. For this to
>>> work, the flag -mmacosx-version-min=10.7 is required, so I use:
>>> CMAKE_CXX_FLAGS:STRING=-mmacosx-version-min=10.7 -stdlib=libc++
>>>
>>> However, around line 140, the CMakeLists.txt of compiler-rt contains:
>>> if(APPLE)
>>>   list(APPEND SANITIZER_COMMON_CFLAGS -mmacosx-version-min=10.5)
>>> endif()
>>>
>>> Now, when building with clang, the minimal minimal version is used, so
>>> 10.5, which results in a compiler error complaining that the minimal
>>> version should be 10.7.
>>>
>>> My question: could you please add some CMake logic to the compiler-rt
>>> CMakeLists.txt to check if there is already a macosx-version-min flag set,
>>> or to not include the flag if -stdlib=libc++ is set?
>>>
>>
Hi Erik,
IIRC, using -stdlib=libc++ on Mac should also require presence of flag
-mmacosx-version-min? If that's the case, then probably we can put the logic
of determining the set of flags required for libc++ into CMake build rules
and use CMake variable like COMPILER_RT_USES_LIBCXX. Does the attached
patch solve a problem for you? If you're building LLVM/Clang tree, however,
we may want to hoist this to smth. like LLVM_USES_LIBCXX.


>
>> I don't know the specific needs of either libc++ or the sanitizer on mac;
>> instead this should be answered by one of the folks actively working on
>> that area. There are several on the list that can likely help.
>>
>


>
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>>
>>
>


-- 
Alexey Samsonov, MSK
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