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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - raw_ostream calls memcpy() with NULL destination in unbuffered mode" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D23650&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=MdW7yJcqHGtsgV72WZKPyvJX_Rpc-YnndSL32yWkzow&s=4WBTu0r1CVlgWe6k7BC-MeZj4mJeEdnKwP1Y733wBQM&e=">23650</a>
</td>
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<th>Summary</th>
<td>raw_ostream calls memcpy() with NULL destination in unbuffered mode
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>3.6
</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>Support Libraries
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>andrey.vihrov@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Using LLVM 3.6 and compiling with GCC 5.1 with UndefinedBehaviorSanitizer
enabled, this program:
#include <llvm/Support/raw_ostream.h>
int main()
{
llvm::errs().SetUnbuffered();
llvm::errs() << "";
}
produces
/usr/include/llvm/Support/raw_ostream.h:171:40: runtime error: null pointer
passed as argument 1, which is declared to never be null
The problematic place is here:
<a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_llvm_trunk_include_llvm_Support_raw-5Fostream.h-3Fview-3Dmarkup-23l168&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=MdW7yJcqHGtsgV72WZKPyvJX_Rpc-YnndSL32yWkzow&s=o1Nts8bzuFNKLpBAMe63miEpYxX0achrVxms9HZIjoI&e=">http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/raw_ostream.h?view=markup#l168</a>
In unbuffered mode, OutBufCur is a null pointer, but when Size == 0, the code
still tries to call memcpy() with it.</pre>
</div>
</p>
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