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

Tue Nov 4 21:02:22 PST 2014

Sorry, I reverted commit 220932 by 221331.

I have to do this because it is a showstopper failure, and all aarch64
target build are being blocked in the past 4 days.

Thanks,
-Jiangning

2014-11-05 9:15 GMT+08:00 Jiangning Liu <liujiangning1 at gmail.com>:

> Sorry, That was my mistake. It just showed my build can pass after
> reverting 220932.
>
> Can this be reverted ASAP? This is actually blocking clang/llvm self-build
> on aarch64 target.
>
> The error message is like,
>
> [ 20%] Building arm_neon.h...
> /bin/sh: line 1: 28055 Segmentation fault
>  ../../../../bin/clang-tblgen -gen-arm-neon -I
> /work/slave/performance-daily/build/tools/clang/lib/Headers -I
> /work/slave/performance-daily/build/lib/Target -I
> /work/slave/performance-daily/build/include
> /work/slave/performance-daily/build/tools/clang/include/clang/Basic/
> arm_neon.td -o
> /work/slave/performance-daily/build/build/tools/clang/lib/Headers/arm_neon.h.tmp
>
> Thanks,
> -Jiangning
>
>
> 2014-11-05 9:01 GMT+08:00 Hal Finkel <hfinkel at anl.gov>:
>
>> ----- Original Message -----
>> > From: "Jiangning Liu" <liujiangning1 at gmail.com>
>> > To: "Chris Bieneman" <beanz at apple.com>
>> > Cc: "Bill Schmidt" <wschmidt at linux.vnet.ibm.com>, "Samuel F Antao" <
>> sfantao at us.ibm.com>, azanella at linux.vnet.ibm.com,
>> > "Hal Finkel" <hfinkel at anl.gov>, "LLVM Dev" <llvmdev at cs.uiuc.edu>,
>> "ulrich weigand" <ulrich.weigand at de.ibm.com>
>> > Sent: Tuesday, November 4, 2014 6:56:07 PM
>> > Subject: Re: Issue with std::call_once in PPC64 platform
>> >
>> > It seems the crash of llvm/clang build on aarch64 Debian has been
>> > fixed by r220941.
>>
>> That's scary. Is there any actual code-generation change from that commit?
>>
>>  -Hal
>>
>> >
>> >
>> > 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
>> > >>>>>>
>> > >>>>>>
>> > >>>>>
>> > >>>>>
>> > >>>>
>> > >>>>
>> > >>>
>> > >>>
>> > >>
>> > >>
>> > >
>> > >
>> >
>> >
>> >
>> >
>>
>> --
>> Hal Finkel
>> Assistant Computational Scientist
>> Leadership Computing Facility
>> Argonne National Laboratory
>>
>
>
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