<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Nested Template Visibility is Not Right"
href="https://bugs.llvm.org/show_bug.cgi?id=36132">36132</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Nested Template Visibility is Not Right
</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>normal
</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>bluechristlove@163.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Code:
#define HIDDEN __attribute__((visibility("hidden")))
#define PROTECTED __attribute__((visibility("protected")))
#define DEFAULT __attribute__((visibility("default")))
template <typename T> class HIDDEN C {
public:
template <typename U> class PROTECTED D {
public:
void f();
};
};
int main() {
C<int>::D<int> d;
d.f();
}
When we compile it and dump the symbol proporty:
Symbol table '.symtab' contains 6 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000000 0 FILE LOCAL DEFAULT ABS c.C
2: 0000000000000000 0 SECTION LOCAL DEFAULT 2
3: 0000000000000000 0 NOTYPE GLOBAL DEFAULT UND .TOC.
4: 0000000000000000 0 NOTYPE GLOBAL HIDDEN UND C<int>::D<int>::f()
5: 0000000000000000 76 FUNC GLOBAL DEFAULT [<localentry>: 8] 2
main
We can see that function's visibility is HIDDEN. But it should belongs to D's
visibility: PROTECTED.
When we use GCC:
Symbol table '.symtab' contains 12 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000000 0 FILE LOCAL DEFAULT ABS c.C
2: 0000000000000000 0 SECTION LOCAL DEFAULT 1
3: 0000000000000000 0 SECTION LOCAL DEFAULT 3
4: 0000000000000000 0 SECTION LOCAL DEFAULT 4
5: 0000000000000000 0 SECTION LOCAL DEFAULT 5
6: 0000000000000000 0 SECTION LOCAL DEFAULT 7
7: 0000000000000000 0 SECTION LOCAL DEFAULT 8
8: 0000000000000000 0 SECTION LOCAL DEFAULT 6
9: 0000000000000000 84 FUNC GLOBAL DEFAULT [<localentry>: 8] 1
main
10: 0000000000000000 0 NOTYPE GLOBAL DEFAULT UND .TOC.
11: 0000000000000000 0 NOTYPE GLOBAL PROTECTED UND
C<int>::D<int>::f()
We can see that GCC's behaviour is right.
Additionally, if we don't use nested template, i.e.
#define HIDDEN __attribute__((visibility("hidden")))
#define PROTECTED __attribute__((visibility("protected")))
#define DEFAULT __attribute__((visibility("default")))
template<typename T>
class HIDDEN C {
public:
class PROTECTED D {
public:
void f();
};
};
int main() {
C<int>::D d;
d.f();
}
Clang can get the right visibility.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>