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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - ppc64 (be and le) don't have a working std::call_once"
href="https://llvm.org/bugs/show_bug.cgi?id=28024">28024</a>
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<th>Summary</th>
<td>ppc64 (be and le) don't have a working std::call_once
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Core LLVM classes
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>chandlerc@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>hfinkel@anl.gov, kbarton@ca.ibm.com, llvm-bugs@lists.llvm.org
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>This appears to be a bug in the libstdc++ implementation of std::call_once, but
it may be somewhat specific to ABI issues as there are differences between
stage1 and stage2 in LE.
Here are the build bot builds that started failing when I landed r271800 that
switch LLVM to use std::call_once on various implementations:
<a href="http://lab.llvm.org:8011/builders/clang-ppc64le-linux-multistage/builds/1169">http://lab.llvm.org:8011/builders/clang-ppc64le-linux-multistage/builds/1169</a>
<a href="http://lab.llvm.org:8011/builders/clang-ppc64be-linux-multistage/builds/2703">http://lab.llvm.org:8011/builders/clang-ppc64be-linux-multistage/builds/2703</a>
These fail in unit tests that use INITIALIZE_PASS which defines a function that
uses std::call_once. The failure happens when the implementation of
std::call_once throws std::system_error with the '-1' return of a call to
pthread_once. I don't know why pthread_once would fail here. I've tried to
reproduce any failure to properly initialize the std::once_flag (which contains
as a member the pthread_once_t variable passed to pthread_once) but to no avail
on my system.
Hopefully someone who works on PPC can figure this out.
Also, when I tried to disable this in r271821, it worked for ppc64le, and for
stage2 in ppc64be, but not for stage1 for some reason! Really weird:
<a href="http://lab.llvm.org:8011/builders/clang-ppc64be-linux-multistage/builds/2707">http://lab.llvm.org:8011/builders/clang-ppc64be-linux-multistage/builds/2707</a>
Again, I can't figure out how or why this would happen. Hopefully some PPC
folks can figure this out.</pre>
</div>
</p>
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