<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_NEW "
title="NEW --- - Broken bitfield debug info in Dwarf4"
href="https://llvm.org/bugs/show_bug.cgi?id=27758">27758</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Broken bitfield debug info in Dwarf4
</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>Linux
</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>DebugInfo
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>mattias.v.eriksson@ericsson.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>I am debugging an issue with bitfields and debug info and found that this
commit is where the problems begin.
The file tmp.c:
struct fields
{
unsigned int a : 1;
unsigned int b : 1;
} f;
int main ()
{
f.a = 1;
return 0;
}
Built with top-of-tree clang and run in gdb:
gdb a.out
GNU gdb (Ubuntu 7.7.1-0ubuntu5~14.04.2) 7.7.1
...
Reading symbols from a.out...done.
(gdb) break main
Breakpoint 1 at 0x40058d: file tmp.c, line 9.
(gdb) run
Starting program: a.out
Breakpoint 1, main () at tmp.c:9
9 f.a = 1;
(gdb) display f
1: f = {a = 0, b = 0}
(gdb) n
10 return 0;
1: f = {a = 1, b = 1} <<<--- Unexpected value of b!
(gdb) x &f
0x402024 <f>: 0x00000001
(gdb)
I have identified the first commit where this is broken as this one:
<a href="http://reviews.llvm.org/D19630">http://reviews.llvm.org/D19630</a></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>