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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Itanium ABI: incorrect mangling of unresolved operator name"
href="http://llvm.org/bugs/show_bug.cgi?id=22584">22584</a>
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<th>Summary</th>
<td>Itanium ABI: incorrect mangling of unresolved operator name
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<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>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>LLVM Codegen
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>Wolfgang_Pieb@playstation.sony.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
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</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Given the following case:
struct S4 {
S4 operator-(S4 rhs) { return rhs; }
};
template<class T> auto kkk(T p)->decltype(&T::operator-){}
template<> decltype(&S4::operator-) kkk(S4 x) { return nullptr; }
clang (r229188) mangles the explicit instantiation of kkk() as:
_Z3kkkI2S4EDTadsrT_miES1_
when the correct mangling should be:
_Z3kkkI2S4EDTadsrT_onmiES1_ (note the additional "on")
The crux is here that T::operator- is an unresolved name and the ABI (chapter
5.1.5) gives the following:
<base-unresolved-name> ::= <simple-id> # unresolved name
::= on <operator-name> # unresolved
operator-function-id
::= on <operator-name> <template-args> # unresolved
operator template-id
and, later, in an example
template<class T> auto f(T p)->decltype(&T::operator-);
// The return type in the mangling of the template signature
// is encoded as "DTadsrT_onmiE".
gcc 4.8.2 is inconsistent. With the above example, it matches clang's
mangling, but with the following example
struct S4 {
S4(int a) {}
};
S4 operator+(S4 lhs, S4 rhs) { return rhs; }
template <class T> auto g(T p1) -> decltype(operator+(p1,p1));
template <> auto g<S4>(S4 p1) -> decltype(operator+(p1,p1)) { return 0; }
gcc mangles the instantiation of g() correctly to:
_Z1gI2S4EDTclonplfp_fp_EET_
whereas clang leaves out the "on"
_Z1gI2S4EDTclplfp_fp_EET_</pre>
</div>
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