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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - clang generates incorrect unwind information on 32-bit mingw"
href="https://bugs.llvm.org/show_bug.cgi?id=40322">40322</a>
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<th>Summary</th>
<td>clang generates incorrect unwind information on 32-bit mingw
</td>
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<th>Product</th>
<td>new-bugs
</td>
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<th>Version</th>
<td>7.0
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>new bugs
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>marc@groundctl.com
</td>
</tr>
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<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=21330" name="attach_21330" title="attached program">attachment 21330</a> <a href="attachment.cgi?id=21330&action=edit" title="attached program">[details]</a></span>
attached program
When compiling the attached program with the arguments "-target
i686-w64-mingw32 -O2", the resulting executable aborts. When compiling with
"-target i686-w64-mingw32 -O0" the executable works correctly.
This appears to be because the generated dwarf unwind information is incorrect.
When the unwinder looks for the return address of "am" it is off by 4 bytes
and finds the argument to "am", which is 0, and so it thinks the stack has
ended.
I am using the current Arch Linux clang build, version "7.0.1
(tags/RELEASE_701/final)". This does not happen when targeting
"x86_64-w64-mingw32". This does not happen when using -O1.</pre>
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