[LLVMdev] Issue with std::call_once in PPC64 platform

[Jiangning Liu]

It seems the crash of llvm/clang build on aarch64 Debian has been fixed by
r220941.

Thanks,
-Jiangning


2014-11-05 8:45 GMT+08:00 Jiangning Liu <liujiangning1 at gmail.com>:

> The versions I'm using right now are
>
> * gcc: (Debian/Linaro 4.9.1-14) 4.9.1
> * libstdc++: libstdc++.so.6.0.20
>
> Thanks,
> -Jiangning
>
> 2014-11-05 4:46 GMT+08:00 Chris Bieneman <beanz at apple.com>:
>
>> Adding Jiangning Liu to the thread.
>>
>> Jiangning reported a similar issue on the llvm-commits list on Debian
>> aarch64.
>>
>> In general it sounds like std::call_once may not really be bug free.
>>
>> Jiangning, can you please provide your gcc/libstdc++ version?
>>
>> Thanks,
>> -Chris
>>
>>
>> > On Nov 4, 2014, at 9:38 AM, Bill Schmidt <wschmidt at linux.vnet.ibm.com>
>> wrote:
>> >
>> > On Tue, 2014-11-04 at 12:17 -0500, Samuel F Antao wrote:
>> >> Ok, I'll put a patch together to fix this later today. I'll probably
>> >> do what Reid was suggesting and use what is already in there for
>> >> Windows.
>> >
>> > Hm, better hold off on that.  Ulrich Weigand has noted that there is
>> > invalid code generation occurring around a TLS call.  Looks like is is
>> > probably a PPC back end problem at the moment.
>> >
>> > Thanks,
>> > Bill
>> >
>> >>
>> >> Thanks,
>> >> Samuel
>> >>
>> >> Bill Schmidt <wschmidt at linux.vnet.ibm.com> wrote on 11/04/2014
>> >> 12:11:08 PM:
>> >>
>> >>> From: Bill Schmidt <wschmidt at linux.vnet.ibm.com>
>> >>> To: Samuel F Antao/Watson/IBM at IBMUS
>> >>> Cc: azanella at linux.vnet.ibm.com, beanz at apple.com, Hal Finkel
>> >>> <hfinkel at anl.gov>, LLVM Dev <llvmdev at cs.uiuc.edu>
>> >>> Date: 11/04/2014 12:11 PM
>> >>> Subject: Re: Issue with std::call_once in PPC64 platform
>> >>>
>> >>> On Tue, 2014-11-04 at 11:59 -0500, Samuel F Antao wrote:
>> >>>> Hi Bill,
>> >>>>
>> >>>> You can find the same issue in the buildbot:
>> >>>>
>> >>>> http://lab.llvm.org:8011/builders/clang-ppc64-elf-linux2/builds/
>> >>> 16444/steps/compile.llvm.stage2/logs/stdio
>> >>>>
>> >>>> It is failing for me both in BE (gcc 4.8.2) and LE(4.9.1). I am
>> >>>> compiling with clang 3.5, but those are the gcc toolchains I am
>> >> using.
>> >>>>
>> >>>> What do you think is the best way to fix this?
>> >>>
>> >>> I don't know what the best fix is, but clearly a fix or revert is
>> >> needed
>> >>> since the patch is breaking some platforms.
>> >>>
>> >>> Thanks,
>> >>> Bill
>> >>>
>> >>>>
>> >>>> Thanks!
>> >>>> Samuel
>> >>>>
>> >>>> Bill Schmidt <wschmidt at linux.vnet.ibm.com> wrote on 11/04/2014
>> >>>> 11:45:06 AM:
>> >>>>
>> >>>>> From: Bill Schmidt <wschmidt at linux.vnet.ibm.com>
>> >>>>> To: Samuel F Antao/Watson/IBM at IBMUS
>> >>>>> Cc: LLVM Dev <llvmdev at cs.uiuc.edu>, beanz at apple.com, Hal Finkel
>> >>>>> <hfinkel at anl.gov>, azanella at linux.vnet.ibm.com
>> >>>>> Date: 11/04/2014 11:45 AM
>> >>>>> Subject: Re: Issue with std::call_once in PPC64 platform
>> >>>>>
>> >>>>> Hi Samuel,
>> >>>>>
>> >>>>> I haven't encountered this problem.  What gcc/libstdc++ are you
>> >>>> using?
>> >>>>> BE or LE?
>> >>>>>
>> >>>>> Copying Adhemerval in case he has heard of any related issues.
>> >>>>>
>> >>>>> Thanks,
>> >>>>> Bill
>> >>>>>
>> >>>>> On Mon, 2014-11-03 at 20:19 -0500, Samuel F Antao wrote:
>> >>>>>> Hi all,
>> >>>>>>
>> >>>>>> I observe that r220932 (Removing the static initializer in
>> >>>>>> ManagedStatic.cpp by using llvm_call_once to initialize the
>> >>>>>> ManagedStatic mutex.) is causing tablegen to segfault in PPC
>> >>>> platforms
>> >>>>>> during static initialization. The crash happens while calling
>> >>>>>> std::call_once introduced by this patch in the wrapper used
>> >> in
>> >>>>>> getManagedStaticMutex.
>> >>>>>>
>> >>>>>> I understand this call is buggy for some platforms (or
>> >> probably
>> >>>> some
>> >>>>>> oldish libstdc++ versions). Is this a known issue? Should we
>> >> guard
>> >>>>>> LLVM_DEFINE_ONCE_FLAG definition with platform specific macros
>> >> to
>> >>>>>> avoid the crash, at least for the moment?
>> >>>>>>
>> >>>>>> Thanks!
>> >>>>>> Samuel
>> >>>>>>
>> >>>>>>
>> >>>>>
>> >>>>>
>> >>>>
>> >>>>
>> >>>
>> >>>
>> >>
>> >>
>> >
>> >
>>
>>
>
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