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<head>
<base href="http://llvm.org/bugs/" />
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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 --- - MS ABI: Alignment of pointer to member is wrong"
href="http://llvm.org/bugs/show_bug.cgi?id=18618">18618</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>MS ABI: Alignment of pointer to member is wrong
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</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>LLVM Codegen
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>david.majnemer@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>consider:
extern "C" int printf(const char *, ...);
static char buffer[419430400];
inline void *operator new(size_t, void *pv) { return pv; }
struct __single_inheritance Single;
struct __multiple_inheritance Multiple;
struct __virtual_inheritance Virtual;
struct Unspecified;
struct C {
char c;
int Single::*Single_field;
int Multiple::*Multiple_field;
int Virtual::*Virtual_field;
int Unspecified::*Unspecified_field;
int (Single::*Single_fun)();
int (Multiple::*Multiple_fun)();
int (Virtual::*Virtual_fun)();
int (Unspecified::*Unspecified_fun)();
C() {
printf("offsetof Single_field %d\n", (int)((char *)&Single_field -
buffer));
printf("alignof Single_field %d\n", __alignof(Single_field));
printf("alignof int Single::* %d\n", __alignof(int Single::*));
printf("offsetof Multiple_field %d\n", (int)((char *)&Multiple_field
- buffer));
printf("alignof Multiple_field %d\n", __alignof(Multiple_field));
printf("alignof int Multiple::* %d\n", __alignof(int Multiple::*));
printf("offsetof Virtual_field %d\n", (int)((char *)&Virtual_field -
buffer));
printf("alignof Virtual_field %d\n", __alignof(Virtual_field));
printf("alignof int Virtual::* %d\n", __alignof(int Virtual::*));
printf("offsetof Unspecified_field %d\n", (int)((char
*)&Unspecified_field - buffer));
printf("alignof Unspecified_field %d\n", __alignof(Unspecified_field));
printf("alignof int Unspecified::* %d\n", __alignof(int
Unspecified::*));
printf("offsetof Single_fun %d\n", (int)((char *)&Single_fun -
buffer));
printf("alignof Single_fun %d\n", __alignof(Single_fun));
printf("alignof int (Single::*)() %d\n", __alignof(int (Single::*)()));
printf("offsetof Multiple_fun %d\n", (int)((char *)&Multiple_fun -
buffer));
printf("alignof Multiple_fun %d\n", __alignof(Multiple_fun));
printf("alignof int (Multiple::*)() %d\n", __alignof(int
(Multiple::*)()));
printf("offsetof Virtual_fun %d\n", (int)((char *)&Virtual_fun -
buffer));
printf("alignof Virtual_fun %d\n", __alignof(Virtual_fun));
printf("alignof int (Virtual::*) %d\n", __alignof(int
(Virtual::*)()));
printf("offsetof Unspecified_fun %d\n", (int)((char *)&Unspecified_fun
- buffer));
printf("alignof Unspecified_fun %d\n", __alignof(Unspecified_fun));
printf("alignof int (Unspecified::*) %d\n", __alignof(int
(Unspecified::*)()));
}
};
int main() { new (buffer) C; }
clang gets:
offsetof Single_field 4
alignof Single_field 4
alignof int Single::* 4
offsetof Multiple_field 8
alignof Multiple_field 4
alignof int Multiple::* 4
offsetof Virtual_field 12
alignof Virtual_field 4
alignof int Virtual::* 4
offsetof Unspecified_field 20
alignof Unspecified_field 4
alignof int Unspecified::* 4
offsetof Single_fun 32
alignof Single_fun 4
alignof int (Single::*)() 4
offsetof Multiple_fun 36
alignof Multiple_fun 4
alignof int (Multiple::*)() 4
offsetof Virtual_fun 44
alignof Virtual_fun 4
alignof int (Virtual::*) 4
offsetof Unspecified_fun 56
alignof Unspecified_fun 4
alignof int (Unspecified::*) 4
msvc gets:
offsetof Single_field 4
alignof Single_field 1
alignof int Single::* 4
offsetof Multiple_field 8
alignof Multiple_field 1
alignof int Multiple::* 4
offsetof Virtual_field 16
alignof Virtual_field 1
alignof int Virtual::* 4
offsetof Unspecified_field 24
alignof Unspecified_field 1
alignof int Unspecified::* 4
offsetof Single_fun 36
alignof Single_fun 1
alignof int (Single::*)() 4
offsetof Multiple_fun 40
alignof Multiple_fun 1
alignof int (Multiple::*)() 4
offsetof Virtual_fun 48
alignof Virtual_fun 1
alignof int (Virtual::*) 4
offsetof Unspecified_fun 64
alignof Unspecified_fun 1
alignof int (Unspecified::*) 4
note that alignof on a field in the struct is different from the field's type.</pre>
</div>
</p>
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