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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Wrong line and backtrace information at Og"
href="https://bugs.llvm.org/show_bug.cgi?id=51511">51511</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Wrong line and backtrace 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>Linux
</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 nop assembly instruction, the source line (line 4) and the
backtrace (main) are wrong.
Steps to reproduce bug:
root@cbf0f3763b8d:/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@cbf0f3763b8d:/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@cbf0f3763b8d:/home/stepping/output# cat -n a.c
1 volatile int a, g_5108 ;
2 int b;
3 short c() {
4 return g_5108;
5 }
6 int main () {
7 c();
8 b = 0;
9 for (;
10 b < 4;
11 b++) a ;
12 }
root@cbf0f3763b8d:/home/stepping/output# cat a.c
volatile int a, g_5108 ;
int b;
short c() {
return g_5108;
}
int main () {
c();
b = 0;
for (;
b < 4;
b++) a ;
}
root@cbf0f3763b8d:/home/stepping/output# clang -Og -g -Wno-everything -o optg
a.c
root@cbf0f3763b8d:/home/stepping/output# lldb optg
(lldb) target create "optg"
Current executable set to '/home/stepping/output/optg' (x86_64).
(lldb) b 0x40049b
Breakpoint 1: address = 0x000000000040049b
(lldb) r
Process 48 launched: '/home/stepping/output/optg' (x86_64)
Process 48 exited with status = 0 (0x00000000)
(lldb) b 0x40049b
Breakpoint 2: where = optg`main + 11 at a.c:4:39, address = 0x000000000040049b
(lldb) r
Process 56 launched: '/home/stepping/output/optg' (x86_64)
Process 56 stopped
* thread #1, name = 'optg', stop reason = breakpoint 2.1
frame #0: 0x000000000040049b optg`main at a.c:4:39
1 volatile int a, g_5108 ;
2 int b;
3 short c() {
-> 4 return g_5108;
5 }
6 int main () {
7 c();
(lldb) di -l
optg`main:
0x400490 <+0>: movl 0x200b96(%rip), %eax ; g_5108
0x400496 <+6>: movl $0x4, %eax
-> 0x40049b <+11>: nopl (%rax,%rax)
(lldb) bt
* thread #1, name = 'optg', stop reason = breakpoint 2.1
* frame #0: 0x000000000040049b optg`main at a.c:4:39
frame #1: 0x00007ffff7a03bf7 libc.so.6`__libc_start_main + 231
frame #2: 0x00000000004003ba optg`_start + 42</pre>
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