<html>
<head>
<base href="https://bugs.llvm.org/">
</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 - Odd Stepping Behaviour"
href="https://bugs.llvm.org/show_bug.cgi?id=46015">46015</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Odd Stepping Behaviour
</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>massarelli@diag.uniroma1.it
</td>
</tr>
<tr>
<th>CC</th>
<td>dblaikie@gmail.com, ditaliano@apple.com, jdevlieghere@apple.com, jeremy.morse.llvm@gmail.com, keith.walker@arm.com, llvm-bugs@lists.llvm.org, paul_robinson@playstation.sony.com
</td>
</tr></table>
<p>
<div>
<pre>From the debugger it seems that func_1 is called twice.
$ cat a.c
static int a;
static int *b = &a;
static int *func_2() {
*b = 0;
return &a;
}
void func_1() { func_2(); }
int main() { func_1(); }
$ clang -v
clang version 11.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
268fa40daa151d3b4bff1df12b62e5dae94685d7)
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
$ lldb -v
lldb version 11.0.0
clang revision 268fa40daa151d3b4bff1df12b62e5dae94685d7
llvm revision 268fa40daa151d3b4bff1df12b62e5dae94685d7
$ clang -Og -g -o opt a.c
$ lldb opt
(lldb) target create "opt"
Current executable set to 'opt' (x86_64).
(lldb) b main
Breakpoint 1: where = opt`main + 1 at a.c:8:14, address = 0x0000000000400491
(lldb) r
Process 60 launched: 'opt' (x86_64)
Process 60 stopped
* thread #1, name = 'opt', stop reason = breakpoint 1.1
frame #0: 0x0000000000400491 opt`main at a.c:8:14
5 return &a;
6 }
7 void func_1() { func_2(); }
-> 8 int main() { func_1(); }
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x0000000000400481 opt`func_1 at a.c:7:17
4 *b = 0;
5 return &a;
6 }
-> 7 void func_1() { func_2(); }
8 int main() { func_1(); }
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x00000000004004a0 opt`func_2 at a.c:8:24
5 return &a;
6 }
7 void func_1() { func_2(); }
-> 8 int main() { func_1(); }
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x0000000000400486 opt`func_1 at a.c:7:27
4 *b = 0;
5 return &a;
6 }
-> 7 void func_1() { func_2(); }
8 int main() { func_1(); }
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x0000000000400496 opt`main at a.c:8:24
5 return &a;
6 }
7 void func_1() { func_2(); }
-> 8 int main() { func_1(); }
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x00007ffff7a05b97 libc.so.6`__libc_start_main + 231
libc.so.6`__libc_start_main:
-> 0x7ffff7a05b97 <+231>: movl %eax, %edi
0x7ffff7a05b99 <+233>: callq 0x7ffff7a27120 ; exit
0x7ffff7a05b9e <+238>: movq 0x3ced23(%rip), %rax
0x7ffff7a05ba5 <+245>: rorq $0x11, %rax
(lldb) ^Z</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>