[llvm-dev] Minimal glibc version supported by LLVM build

[Philip Reames via llvm-dev]

3rd time the charm?

On 10/04/2017 11:18 AM, Philip Reames via llvm-dev wrote:
>
> + Rafael, the actual patch author.  Don't know how I misread that, sorry.
>
>
> On 10/04/2017 11:17 AM, Philip Reames wrote:
>>
>> + Rui, the patch author
>>
>> Do we know what the oldest glibc which works with this patch is?
>>
>> For context, the most recent REHL 5 ships with glibc 2.5. REHL 6 
>> ships with 2.12 and REHL ships with 2.17.  I have evidence that this 
>> breaks at least on Centos 6.4 which is derived from REHL 6.
>>
>> This appears to break on anything REHL 6 (or earlier) derived.  I 
>> think this patch needs to be reverted.  Thoughts?
>>
>> Philip
>>
>>
>> On 10/04/2017 12:08 AM, Serguei Katkov via llvm-dev wrote:
>>>
>>> Hi All,
>>>
>>> The landed patch https://reviews.llvm.org/D38481 introduced the 
>>> usage of CPU_COUNT defined in glibc sched.h header.
>>>
>>> I failed to find this symbol in sched.h of glibc version 2.5-24, so 
>>> compilation just fails.
>>>
>>> /home/dolphin/merge-from-upstream-area/ws/pristine/lib/Support/Threading.cpp: 
>>> In function ‘unsigned int llvm::hardware_concurrency()’:
>>>
>>> /home/dolphin/merge-from-upstream-area/ws/pristine/lib/Support/Threading.cpp:80:26: 
>>> error: ‘CPU_COUNT’ was not declared in this scope
>>>
>>>      return CPU_COUNT(&Set);
>>>
>>>                           ^
>>>
>>> It is buildable with newest version of glibc.
>>>
>>> I tried to find a requirements for glibc version in LLVM 
>>> documentation but failed.
>>>
>>> So I wonder whether there is such requirement or not.
>>>
>>> Could anyone point me to this documentation?
>>>
>>> I'm trying to understand whether patch is wrong which relies on 
>>> availability of library but does not check the symbol itself or this 
>>> version of glibc is not supported.
>>>
>>> Thank you,
>>>
>>> Serguei.
>>>
>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
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>>
>
>
>
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