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<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Wrong backtrace and source line information at Og"
href="https://bugs.llvm.org/show_bug.cgi?id=51750">51750</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Wrong backtrace and source line information at Og
</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>Windows NT
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</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>artuso@diag.uniroma1.it
</td>
</tr>
<tr>
<th>CC</th>
<td>jdevlieghere@apple.com, keith.walker@arm.com, llvm-bugs@lists.llvm.org, paul_robinson@playstation.sony.com
</td>
</tr></table>
<p>
<div>
<pre>Comment:
When stepping on the "pushq %rax" assembly instruction the backtrace indicates
that we are inside the main function and the associated source line is wrong
(line 17, which is in function w). The "pushq %rax" instruction should point to
line 0.
Steps to reproduce bug:
root@b04800b37146:/home/stepping/output# clang -v
clang version 14.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
957334382cd12ec07b46c0ddfdcc220731f6d80f)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Candidate multilib: .;@m64
Selected multilib: .;@m64
root@b04800b37146:/home/stepping/output# lldb -v
lldb version 14.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a> revision
957334382cd12ec07b46c0ddfdcc220731f6d80f)
clang revision 957334382cd12ec07b46c0ddfdcc220731f6d80f
llvm revision 957334382cd12ec07b46c0ddfdcc220731f6d80f
root@b04800b37146:/home/stepping/output# cat a.c
volatile int a, c, e;
short d;
int f;
char g, h, k;
int j;
unsigned l;
static short m[] = {3, 3, 3, 3, 3, 3, 3};
int n;
int(o)() {
f = o();
if (f)
m[2] = e;
}
void p() {
int b[6];
int i;
for (i = 0; i < 6; i++)
b[i] = 10;
d = 0;
for (; d <= 5; d++) {
j |= 6;
h = g++;
b[2] | m[6] || (l = k);
}
}
int main() {
p();
for (; n;)
c = a * 7;
a = j;
a = h;
a = m[g];
printf("%X\n");
}
root@b04800b37146:/home/stepping/output# cat -n a.c
1 volatile int a, c, e;
2 short d;
3 int f;
4 char g, h, k;
5 int j;
6 unsigned l;
7 static short m[] = {3, 3, 3, 3, 3, 3, 3};
8 int n;
9 int(o)() {
10 f = o();
11 if (f)
12 m[2] = e;
13 }
14 void p() {
15 int b[6];
16 int i;
17 for (i = 0; i < 6; i++)
18 b[i] = 10;
19 d = 0;
20 for (; d <= 5; d++) {
21 j |= 6;
22 h = g++;
23 b[2] | m[6] || (l = k);
24 }
25 }
26 int main() {
27 p();
28 for (; n;)
29 c = a * 7;
30 a = j;
31 a = h;
32 a = m[g];
33 printf("%X\n");
34 }
root@b04800b37146:/home/stepping/output# lldb opt
(lldb) target create "opt"
Current executable set to '/home/stepping/output/opt' (x86_64).
(lldb) b 0x400556
Breakpoint 1: address = 0x0000000000400556
(lldb) r
Process 50577 launched: '/home/stepping/output/opt' (x86_64)
FFFFE5F8
Process 50577 exited with status = 0 (0x00000000)
(lldb) b 0x400556
Breakpoint 2: where = opt`main + 22 [inlined] p + 6 at a.c:17:3, address =
0x0000000000400556
(lldb) r
Process 50585 launched: '/home/stepping/output/opt' (x86_64)
Process 50585 stopped
* thread #1, name = 'opt', stop reason = breakpoint 2.1
frame #0: 0x0000000000400556 opt`main [inlined] p at a.c:17:3
14 void p() {
15 int b[6];
16 int i;
-> 17 for (i = 0; i < 6; i++)
18 b[i] = 10;
19 d = 0;
20 for (; d <= 5; d++) {
(lldb) di -l
opt`main:
0x400554 <+20>: jne 0x400550 ; <+16> [inlined] p at
a.c:17:17
-> 0x400556 <+22>: pushq %rax
0x400557 <+23>: movl 0x200ae2(%rip), %r9d ; j
0x40055e <+30>: movw $0x6, %dx
0x400562 <+34>: movb 0x200adc(%rip), %al ; g
0x400568 <+40>: nopl (%rax,%rax)
(lldb) bt
* thread #1, name = 'opt', stop reason = breakpoint 2.1
* frame #0: 0x0000000000400556 opt`main [inlined] p at a.c:17:3
frame #1: 0x0000000000400550 opt`main at a.c:27:3
frame #2: 0x00007ffff7a03bf7 libc.so.6`__libc_start_main + 231
frame #3: 0x000000000040040a opt`_start + 42</pre>
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