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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 debug info between step and stepi at -O1"
href="https://bugs.llvm.org/show_bug.cgi?id=46040">46040</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Inconsistent debug info between step and stepi at -O1
</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=23522" name="attach_23522" title="the binary">attachment 23522</a> <a href="attachment.cgi?id=23522&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 main
Breakpoint 1: where = a.out`main + 1 at small.c:19:3, address =
0x00000000004011d1
(lldb) r
Process 35712 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 35712 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x00000000004011d1 a.out`main at small.c:19:3
16 }
17
18 int main() {
-> 19 f(1);
20 }
21
(lldb) step
Process 35712 stopped
* thread #1, name = 'a.out', stop reason = step in
frame #0: 0x0000000000401170 a.out`f(n=<unavailable>) at small.c:8:18
5 char *end;
6 int i;
7
-> 8 for(i=0; i<2; i++) {
9 va_start(ap, n);
10 while (1) {
11 end = va_arg(ap, char *);
(lldb) step
Process 35712 stopped
* thread #1, name = 'a.out', stop reason = step in
frame #0: 0x0000000000401179 a.out`f(n=<unavailable>) at small.c:9:5
6 int i;
7
8 for(i=0; i<2; i++) {
-> 9 va_start(ap, n);
10 while (1) {
11 end = va_arg(ap, char *);
12 if (!end) break;
(lldb) step
Process 35712 stopped
* thread #1, name = 'a.out', stop reason = step in
frame #0: 0x00000000004011a4 a.out`f(n=<unavailable>) at small.c:11:13
8 for(i=0; i<2; i++) {
9 va_start(ap, n);
10 while (1) {
-> 11 end = va_arg(ap, char *);
12 if (!end) break;
13 }
14 va_end(ap);
(lldb) fr var i
(int) i = 1
(lldb)
/************************************
As showed, when step to line 11 (first hit), the value of "i" is equal to 1.
while step-i to line 11 (first hit), the value of "i" is 0, which is as
expected.
************************************/
$ 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 main
Breakpoint 1: where = a.out`main + 1 at small.c:19:3, address =
0x00000000004011d1
(lldb) r
Process 35938 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 35938 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x00000000004011d1 a.out`main at small.c:19:3
16 }
17
18 int main() {
-> 19 f(1);
20 }
21
(lldb) si -c 19
Process 35938 stopped
* thread #1, name = 'a.out', stop reason = instruction step into
frame #0: 0x00000000004011a4 a.out`f(n=<unavailable>) at small.c:11:13
8 for(i=0; i<2; i++) {
9 va_start(ap, n);
10 while (1) {
-> 11 end = va_arg(ap, char *);
12 if (!end) break;
13 }
14 va_end(ap);
(lldb) fr var i
(int) i = 0
(lldb)</pre>
</div>
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