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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - boost::function generates invalid code when using precompiled headers"
href="http://llvm.org/bugs/show_bug.cgi?id=20324">20324</a>
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<tr>
<th>Summary</th>
<td>boost::function generates invalid code when using precompiled headers
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>3.4
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>-New Bugs
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>himikof@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=12777" name="attach_12777" title="The reduced test case">attachment 12777</a> <a href="attachment.cgi?id=12777&action=edit" title="The reduced test case">[details]</a></span>
The reduced test case
A function-template-local const static POD variable in boost::function
implementation (from Boost 1.55) emits invalid LLVM IR when using precompiled
headers.
The variables from specializations are emitted as internal constants, not
linkonce_odr constants, and references to this variable are sometimes wrong:
they reference the variable from a different specialization, using bitcast to
convert its type.
The impact of this bug seems quite severe: it makes boost::function
constructors sometimes crash if precompiled headers are used.
See the attached (standalone) testcase, reduced from Boost.Function
implementation. It has the following structure:
fr.h - several definitions reduced from Boost.Function
stdafx.h - the header PCH is generated from (includes fr.h)
test.cpp - the main file
make.sh - a simple build script
The boost::fr::assign_to::stored_vtable is the offending variable. There are
two runtime asserts at the end of boost::fr::assign_to that should always hold,
but they fail when "test" binary is run. Also, the invalid bitcast can be seen
in the test.ir file by "grep -E 'bitcast.+stored_vtable' test.ir".
This bug disappears if PCH is not used, and code is compiled directly. Also, I
could not reproduce it on clang 3.3.
Clang version:
clang version 3.4.2 (tags/RELEASE_34/dot2-final)
Target: x86_64-pc-linux-gnu
Thread model: posix
Selected GCC installation: /usr/lib/gcc/x86_64-pc-linux-gnu/4.7.3</pre>
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