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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Wrong debug info generated at -O1 (-O0/O2/O3 are correct)"
href="https://bugs.llvm.org/show_bug.cgi?id=46007">46007</a>
</td>
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<th>Summary</th>
<td>Wrong debug info generated at -O1 (-O0/O2/O3 are correct)
</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>yangyibiao@hust.edu.cn
</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>The expected output from lldb should be 1, but lldb outputs -8434 when the
program is compiled with "-O1". It behaves correctly when the program is
compiled with "-O0", "-O2", and "-O3".
$ cat small.c
void foo(char *x) {
*x = 1;
}
int main(int argc, char **argv) {
char c[10];
foo(c);
return 0;
}
$ cat cmds
b 8
r
p argc
$ 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 -g -O1 small.c; lldb -s cmds -b a.out
(lldb) target create "a.out"
Current executable set to '/home/yibiao/Debugger/a.out' (x86_64).
(lldb) command source -s 0 'cmds'
Executing commands in '/home/yibiao/Debugger/cmds'.
(lldb) b 8
Breakpoint 1: where = a.out`main + 14 at small.c:8:3, address =
0x000000000040112e
(lldb) r
Process 8665 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x000000000040112e a.out`main(argc=-8434,
argv=0x00007fffffffe008) at small.c:8:3
5 int main(int argc, char **argv) {
6 char c[10];
7 foo(c);
-> 8 return 0;
9 }
Process 8665 launched: '/home/yibiao/Debugger/a.out' (x86_64)
(lldb) p argc
(int) $0 = -8434
/********************
When compiled with "-O0/O2/-O3", the value of argv is correct as follow.
*********************/
$ clang -g -O3 small.c; lldb -s cmds -b a.out
(lldb) target create "a.out"
Current executable set to '/home/yibiao/Debugger/a.out' (x86_64).
(lldb) command source -s 0 'cmds'
Executing commands in '/home/yibiao/Debugger/cmds'.
(lldb) b 8
Breakpoint 1: where = a.out`main at small.c:8:3, address = 0x0000000000401120
(lldb) r
Process 8765 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x0000000000401120 a.out`main(argc=1, argv=0x00007fffffffe008) at
small.c:8:3
5 int main(int argc, char **argv) {
6 char c[10];
7 foo(c);
-> 8 return 0;
9 }
Process 8765 launched: '/home/yibiao/Debugger/a.out' (x86_64)
(lldb) p argc
(int) $0 = 1</pre>
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