<html>
<head>
<base href="https://llvm.org/bugs/" />
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED --- - @llvm.objectsize treats allocsize differently than allocas."
href="https://llvm.org/bugs/show_bug.cgi?id=28834">28834</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>@llvm.objectsize treats allocsize differently than allocas.
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</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>ASSIGNED
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Global Analyses
</td>
</tr>
<tr>
<th>Assignee</th>
<td>george.burgess.iv@gmail.com
</td>
</tr>
<tr>
<th>Reporter</th>
<td>george.burgess.iv@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>For the purposes of evaluating `@llvm.objectsize(%p)`, we're meant to treat `%p
= call i8* @foo(i32 5)` the same as `%p = alloca i8, i32 5` (assuming @foo has
the allocsize attribute).
This seems not to be the case. Given:
```
void bos(char *a, char *b) {
g0 = __builtin_object_size(a, 0);
g1 = __builtin_object_size(b, 1);
}
void bos1() {
char cs[5], cz[8];
bos(cs, cz);
}
```
We generate (with clang trunk, -O2):
```
define void @bos1() {
entry:
store i32 5, i32* @g0, align 4
store i32 8, i32* @g1, align 4
ret void
}
```
Which is good. Given its allocsize equivalent:
```
// N.B. alloc_size DNE in clang yet.
void *malloc2(int n) __attribute((alloc_size(1)));
void allocsize(int a, int b) {
void *p = malloc2(a);
g0 = __builtin_object_size(p, 0);
void *v = malloc2(b);
g1 = __builtin_object_size(v, 1);
}
void allocsize1() {
allocsize(5, 8);
}
```
We get:
```
define void @allocsize1() {
entry:
store i32 -1, i32* @g0, align 4
store i32 -1, i32* @g1, align 4
ret void
}
```
...Those -1s should be 5 and 8.</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>