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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 - Type merging in some PDBs results in bad pointer typedefs"
href="https://bugs.llvm.org/show_bug.cgi?id=37492">37492</a>
</td>
</tr>
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<th>Summary</th>
<td>Type merging in some PDBs results in bad pointer typedefs
</td>
</tr>
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<th>Product</th>
<td>lld
</td>
</tr>
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<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>COFF
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>amccarth@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>The type records for some typedefs, like `std::vector<unsigned
char>::const_pointer`, sometimes do not have the correct pointee type. It
should be `const unsigned char`, but it's a bitfield. Similar problem for
`const_reference` and `std::array<unsigned char>`.
Discovered in the webview.dll.pdb from a debug Chrome build.
You can observe the problem by running `llvm-pdbutil pretty -types
webview.dll.pdb`, which will effective assert on the bad type. If you use
`dump -types`, you can manually follow the type IDs to an `LF_BITFIELD`.
This does not happen for all PDBs.
Here are some excerpts to illustrate:
```
0x3E25 | LF_CLASS [size = 124] `std::vector<unsigned
char,std::allocator<unsigned char> >`
unique name: `.?AV?$vector@EV?$allocator@E@std@@@std@@`
vtable: <no type>, base list: <no type>, field list: 0x3E24
options: contains nested class | has unique name
```
If we look in the field list for 0x3E24, we find:
```
- LF_NESTTYPE [name = `const_pointer`, parent = 0x27F1]
```
Following the parent:
```
0x27F1 | LF_POINTER [size = 12]
referent = 0x22C6, mode = pointer, opts = None, kind = ptr32
```
And finally, the referent leads to:
```
0x22C6 | LF_BITFIELD [size = 12]
type = 0x0020 (unsigned char), bit offset = 0, # bits = 1
```</pre>
</div>
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