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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 laying out class hierarchy on i686-windows-msvc"
href="https://bugs.llvm.org/show_bug.cgi?id=36748">36748</a>
</td>
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<tr>
<th>Summary</th>
<td>Assertion failure laying out class hierarchy on i686-windows-msvc
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</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>C++
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>smeenai@fb.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk, rnk@google.com
</td>
</tr></table>
<p>
<div>
<pre>% cat /tmp/reduced.cpp
struct S {
S() {}
S(const S &) {}
};
struct T {
~T() {}
};
struct U {
U(S) {}
};
struct V : public T, public U {
using U::U;
};
void f() {
S s;
V v(s);
}
% clang -cc1 -triple i686-windows-msvc -fexceptions -emit-llvm /tmp/reduced.cpp
clang: ../../../include/llvm/Support/Casting.h:255: typename
llvm::cast_retty<X, Y*>::ret_type llvm::cast(Y*) [with X =
clang::CXXMethodDecl; Y = const clang::Decl; typename llvm::cast_retty<X,
Y*>::ret_type = const clang::CXXMethodDecl*]: Assertion `isa<X>(Val) &&
"cast<Ty>() argument of incompatible type!"' failed.
Doesn't occur on x86_64. I can also trigger a slightly different assertion
failure by adding another class to the hierarchy:
struct W : public V {
W(S s) : V(s) {}
};
void f() {
S s;
W w(s);
}
% clang -cc1 -triple i686-windows-msvc -fexceptions -emit-llvm
/tmp/reduced2.cpp
clang: ../../../tools/clang/include/clang/AST/RecordLayout.h:225:
clang::CharUnits clang::ASTRecordLayout::getBaseClassOffset(const
clang::CXXRecordDecl*) const: Assertion `CXXInfo->BaseOffsets.count(Base) &&
"Did not find base!"' failed.
I assume the underlying root cause is the same.</pre>
</div>
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