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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - inconsistent behaviors at -O1 (-O0 is correct)"
href="https://bugs.llvm.org/show_bug.cgi?id=46030">46030</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>inconsistent behaviors at -O1 (-O0 is correct)
</td>
</tr>
<tr>
<th>Product</th>
<td>lldb
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</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>All Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>lldb-dev@lists.llvm.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>yangyibiao@hust.edu.cn
</td>
</tr>
<tr>
<th>CC</th>
<td>jdevlieghere@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=23516" name="attach_23516" title="the binary">attachment 23516</a> <a href="attachment.cgi?id=23516&action=edit" title="the binary">[details]</a></span>
the binary
$ clang --version
clang version 11.0.0 (/home/yibiao/.cache/yay/llvm-git/llvm-project
871beba234a83a2a02da9dedbd59b91a1bfbd7af)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
$ lldb --version
lldb version 11.0.0
clang revision 871beba234a83a2a02da9dedbd59b91a1bfbd7af
llvm revision 871beba234a83a2a02da9dedbd59b91a1bfbd7af
$ clang -O1 -g small.c
$ lldb a.out
(lldb) target create "a.out"
Current executable set to '/home/yibiao/Debugger/a.out' (x86_64).
(lldb) b 10
Breakpoint 1: where = a.out`f + 126 at small.c:10:12, address =
0x000000000040118e
(lldb) r
Process 310513 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 310513 exited with status = 0 (0x00000000)
(lldb)
/************************************
As showed, when setting breakpoint on Line 10, lldb exit directly.
However, when step-i, Line 10 is hit by lldb as follow:
************************************/
$ lldb a.out
(lldb) target create "a.out"
Current executable set to '/home/yibiao/Debugger/a.out' (x86_64).
(lldb) b main
Breakpoint 1: where = a.out`main + 1 at small.c:16:3, address =
0x00000000004011c1
(lldb) r
Process 310470 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 310470 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x00000000004011c1 a.out`main at small.c:16:3
13 }
14
15 int main() {
-> 16 f(1, "ab");
17 }
18
(lldb) si -c 25
Process 310470 stopped
* thread #1, name = 'a.out', stop reason = instruction step into
frame #0: 0x00000000004011ac a.out`f(p=<unavailable>) at small.c:10:12
7 va_start(ap, p);
8 while (1) {
9 v = va_arg(ap, char *);
-> 10 if (!v) break;
11 }
12 va_end(ap);
13 }
(lldb)
$ cat small.c
#include <stdarg.h>
void f(int p, ...) {
va_list ap;
char *v;
va_start(ap, p);
while (1) {
v = va_arg(ap, char *);
if (!v) break;
}
va_end(ap);
}
int main() {
f(1, "ab");
}</pre>
</div>
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