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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 -O0"
href="https://bugs.llvm.org/show_bug.cgi?id=46032">46032</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>inconsistent behaviors at -O0
</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=23517" name="attach_23517" title="the binary">attachment 23517</a> <a href="attachment.cgi?id=23517&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 -O0 -g small.c
$ lldb a.out
(lldb) target create "a.out"
Current executable set to '/home/yibiao/Debugger/a.out' (x86_64).
(lldb) b 13
Breakpoint 1: where = a.out`f + 90 at small.c:13:5, address =
0x000000000040118a
(lldb) r
Process 336948 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 336948 exited with status = 0 (0x00000000)
(lldb)
/************************************
As showed, when setting breakpoint on Line 13, lldb exit directly.
However, when step-i, Line 13 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 + 15 at small.c:24:3, address =
0x00000000004011cf
(lldb) r
Process 336902 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 336902 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x00000000004011cf a.out`main at small.c:24:3
21 }
22
23 int main() {
-> 24 f("u3");
25 return 0;
26 }
(lldb) si -c 674
Process 336902 stopped
* thread #1, name = 'a.out', stop reason = instruction step into
frame #0: 0x000000000040118f a.out`f(p="u3") at small.c:13:16
10 r = strcmp(p, c[m]);
11 if(r<0) {
12 l = m;
-> 13 } else if(r>0) {
14 s = m;
15 } else {
16 return 1;
(lldb)
$ cat small.c
#include <string.h>
char *c[3]={"u1", "u2", "u3"};
int f(char *p)
{
int r, m=3, s=0, l=3;
while(1) {
m = (s+l)/2;
r = strcmp(p, c[m]);
if(r<0) {
l = m;
} else if(r>0) {
s = m;
} else {
return 1;
}
}
return 0;
}
int main() {
f("u3");
return 0;
}</pre>
</div>
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