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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Assertion failure when emitting call to __dfsan_mem_transfer_callback"
href="https://bugs.llvm.org/show_bug.cgi?id=50075">50075</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Assertion failure when emitting call to __dfsan_mem_transfer_callback
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Miscellaneous Instrumentation passes
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>elia.f.geretto@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=24784" name="attach_24784" title="Bitcode reproducer">attachment 24784</a> <a href="attachment.cgi?id=24784&action=edit" title="Bitcode reproducer">[details]</a></span>
Bitcode reproducer
When processing the following function, DFSan triggers the assertion "Calling a
function with a bad signature!" in `DFSanVisitor::visitMemTransferInst`:
```
; Function Attrs: nounwind uwtable
define dso_local i32 @b() local_unnamed_addr #0 {
entry:
call void @llvm.memcpy.p0i8.p0i8.i32(
i8* nonnull align 16 dereferenceable(5) bitcast ([10 x i32]* @a to i8*),
i8* nonnull align 1 dereferenceable(5) getelementptr inbounds ([5 x i8], [5
x i8]* @.str.1, i64 0, i64 0),
i32 5,
i1 false)
ret i32 undef
}
```
The problem is due to the fact that the length of the
`llvm.memcpy.p0i8.p0i8.i32` intrinsic, which is an `i32`, is passed to the
`__dfsan_mem_transfer_callback` function, which instead takes an `i64`.
The bug is reproducible with the bitcode file attached using the following
command:
```
opt -dfsan -dfsan-event-callbacks minigzip_opt.bc -disable-output
```</pre>
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