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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Half-baked clang warning about address of members of packed structs"
href="https://llvm.org/bugs/show_bug.cgi?id=30737">30737</a>
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<tr>
<th>Summary</th>
<td>Half-baked clang warning about address of members of packed structs
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</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>
<tr>
<th>Component</th>
<td>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>stark@mit.edu
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=17461" name="attach_17461" title="Minimal test case with actual code from production">attachment 17461</a> <a href="attachment.cgi?id=17461&action=edit" title="Minimal test case with actual code from production">[details]</a></span>
Minimal test case with actual code from production
I'm using clang 4.0 on Debian and getting spurious "address-of-packed-member"
warnings.
The struct in question is declared with
__attribute__((packed))
__attribute__((aligned(2)))
and consists of three unsigned shorts.
So it seems the warning is triggering without regard to the actual alignment of
the struct and its members and without regard to the actual storage aligment of
the struct.
$ /usr/bin/clang-4.0 -v
clang version 4.0.0-svn283054-1~exp1 (trunk)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/5
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/5.4.1
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/6
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/6.2.0
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.1
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.4.1
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6.2.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.1
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.2.0
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6.2.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64</pre>
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