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This queue is for tickets about the Memcached-libmemcached CPAN distribution.

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The Basics
Id: 88378
Status: stalled
Priority: 0/
Queue: Memcached-libmemcached
People
Owner: Nobody in particular
Requestors: zefram [...] fysh.org
Cc:
AdminCc:
Bug Information
Severity: (no value)
Broken in: (no value)
Fixed in: (no value)

History Show all quoted text
  Tue Sep 03 08:11:06 2013 zefram [...] fysh.org - Ticket created
Subject: compile missing libcloog-ppl0 on Debian
Date: Tue, 3 Sep 2013 13:10:46 +0100
To: bug-Memcached-libmemcached [...] rt.cpan.org
From: Zefram <zefram [...] fysh.org>
Attempting to build Memcached-libmemcached-1.001701 on current Debian stable yields a curious compilation error: libhashkit/crc32.cc: In function 'uint32_t hashkit_crc32(const char*, size_t, void*)': libhashkit/crc32.cc:112:10: sorry, unimplemented: Graphite loop optimizations can only be used if the libcloog-ppl0 package is installed Full build log is attached. Installing the Debian libcloog-ppl0 does resolve this, allowing the module to be successfully installed. As the libmemcached source doesn't appear to be trying to use any feature that might not be available -- the error message actually points at a function definition -- I suspect that the fault lies with the Debian toolchain. Possibly libmemcached is clashing with some symbols that have magic behaviour in the compiler. I'm going to report it as a Debian bug in case that's what it is. -zefram

Message body is not shown because sender requested not to inline it.

  Tue Sep 03 08:46:28 2013 zefram [...] fysh.org - Correspondence added
Subject: Re: [rt.cpan.org #88378] AutoReply: compile missing libcloog-ppl0 on Debian
Date: Tue, 3 Sep 2013 13:46:14 +0100
To: Bugs in Memcached-libmemcached via RT <bug-Memcached-libmemcached [...] rt.cpan.org>
From: Zefram <zefram [...] fysh.org>
My earlier speculation was wrong. The problem arises from compiling libmemcached with g++'s -floop-parallelize-all option (along with -O2). g++-4.7(1) says of the option: # -floop-parallelize-all # Use the Graphite data dependence analysis to identify loops that # can be parallelized. Parallelize all the loops that can be # analyzed to not contain loop carried dependences without checking # that it is profitable to parallelize the loops. The man page has some notes, in multiple places, that "GCC has to be configured with --with-ppl and --with-cloog to enable the Graphite loop transformation infrastructure". Apparently Debian has some funny arrangement where the feature is optionally available, and installing the libcloog-ppl0 library enables it without requiring a gcc rebuild. src/libmemcached/configure has a specific test for availability of the -floop-parallelize-all option. It tries compiling a trivial program with the option, and this passes. It turns out that the unavailability of Graphite is only reported when the option is used *and* the program contains a sufficiently complex loop that gcc wants to invoke Graphite. (Presumably the error message points at the head of the function because it's in a later compiler phase that looks at the whole function.) Accepting the option silently for a sufficiently simple program means that the configure test is misled. You need a workaround along the lines of including some complex loop code in the configure test. I'm also (still) going to report this as a Debian bug, as the compiler is accepting the option in a misleading manner. -zefram
  Tue Sep 03 09:43:43 2013 zefram [...] fysh.org - Correspondence added
Subject: Re: [rt.cpan.org #88378] AutoReply: compile missing libcloog-ppl0 on Debian
Date: Tue, 3 Sep 2013 14:43:24 +0100
To: Bugs in Memcached-libmemcached via RT <bug-Memcached-libmemcached [...] rt.cpan.org>
From: Zefram <zefram [...] fysh.org>
Debian bug report: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=721720 -zefram
  Sat Sep 28 16:50:38 2013 TIMB [...] cpan.org - Correspondence added
For the record, I filed a bug report against libmemcached: https://bugs.launchpad.net/libmemcached/+bug/1232551
  Sat Sep 28 16:50:38 2013 The RT System itself - Status changed from 'new' to 'open'
  Fri Mar 14 10:36:14 2014 WolfSage [...] cpan.org - Correspondence added
On Tue Sep 03 09:43:43 2013, zefram@fysh.org wrote: Show quoted text
> Debian bug report: > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=721720 > > -zefram
This should be "worked around" by now in http://metacpan.org/release/WOLFSAGE/Memcached-libmemcached-1.001702 If you're happy with this, I think we can close (or stall) this ticket until upstream fixes the issues.
  Fri Mar 14 10:45:40 2014 zefram [...] fysh.org - Correspondence added
Subject: Re: [rt.cpan.org #88378] compile missing libcloog-ppl0 on Debian
Date: Fri, 14 Mar 2014 14:45:29 +0000
To: Matthew Horsfall via RT <bug-Memcached-libmemcached [...] rt.cpan.org>
From: Zefram <zefram [...] fysh.org>
Matthew Horsfall via RT wrote: Show quoted text
>This should be "worked around" by now in http://metacpan.org/release/WOLFSAGE/Memcached-libmemcached-1.001702
The workaround, of removing the flawed autodetection of -floop-parallelize-all, is sufficient. I'm happy with this. -zefram
  Fri Mar 14 10:49:54 2014 WolfSage [...] cpan.org - Correspondence added
Stalling to track upstream resolution.
  Fri Mar 14 10:49:55 2014 WolfSage [...] cpan.org - Status changed from 'open' to 'stalled'