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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Windows debug symbols don't show vtcast information"
href="https://bugs.llvm.org/show_bug.cgi?id=38944">38944</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Windows debug symbols don't show vtcast information
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Windows NT
</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>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>dmajor@mozilla.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, rnk@google.com, zturner@google.com
</td>
</tr></table>
<p>
<div>
<pre>struct MyInterface
{
virtual int F() = 0;
};
struct MyClass1 : public MyInterface
{
int F() { return 1; }
} g_myClass1;
struct MyClass2 : public MyInterface
{
int F() { return 2; }
} g_myClass2;
int main(int argc, char* argv[])
{
MyInterface* volatile ptr;
ptr = &g_myClass1;
if (argc) ptr = &g_myClass2;
__debugbreak();
int result = ptr->F();
return result;
}
clang-cl -c -GR- -Z7 x.cpp
lld-link -debug -nodefaultlib -entry:main x.obj
windbg -g x.exe
At the breakpoint, open the Locals window (Alt+3).
With cl.exe + link.exe, you can expand the `ptr` node and see a vtcast option:
- ptr 0x00007ff7`13ffff10 struct MyInterface *
+ __vtcast_MyClass2 struct MyClass2
+ __vfptr 0x00007ff7`13fec050 x!MyClass2::`vftable' = Array [1]
With clang-cl + lld-link, `ptr` isn't even expandable:
ptr 0x00007ff7`c8b73008 struct MyInterface *
Reduced from <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=1490743">https://bugzilla.mozilla.org/show_bug.cgi?id=1490743</a></pre>
</div>
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