<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 - Missing variables after SimplifyCFG at O2"
href="https://bugs.llvm.org/show_bug.cgi?id=51782">51782</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Missing variables after SimplifyCFG at O2
</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>cristianassaiante@outlook.com
</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>Upon calling a function from an external module, the first 9 variables passed
to it are not visible from lldb. Using -opt-bisect-limit we discovered that the
pass causing the symbols disappear is "SimplifyCFGPass on function (main)"
$ cat a.c
int b ;
static int a()
{
char l_287 = 1, l_342 = 5;
int l_326 = 0, l_341 = 1, l_363 = 0, l_387 = 3, l_436 = 0, i, j;
short l_343 = 3, l_412 = 0, l_413 = 1;
i = 0;
for (; i < 2; i++)
{
j = 0;
for (; j < 7; j++)
{
test_nop();
test_support_3073(l_287, l_326, l_341, l_342, l_343, l_363, l_387, l_412,
l_413, l_436, i, j);
}
}
}
int main ()
{
for (; b < 10; b++)
a();
}
$ cat lib/test.c
#include <stdio.h>
#include <stdint.h>
#include "test.h"
void test_nop() {
printf("\n");
}
void test_support_3073(int l_287, int l_326, int l_341, int l_342, int l_343,
int l_363, int l_387, int l_412, int l_413, int l_436, int i, int j) {
printf("%d %d %d %d %d %d %d %d %d %d %d %d", l_287, l_326, l_341, l_342,
l_343, l_363, l_387, l_412, l_413, l_436, i, j);
}
$ cat lib/test.h
#pragma once
void test_nop();
void test_support_3073(int l_287, int l_326, int l_341, int l_342, int l_343,
int l_363, int l_387, int l_412, int l_413, int l_436, int i, int j);
$ clang -v
clang version 13.0.0
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 13.0.0
clang revision c2c977ce50597b0e5186afc342c5784bd0aa6973
lldb revision c2c977ce50597b0e5186afc342c5784bd0aa6973
$ clang -g -O2 -o opt lib/test.c a.c
$ lldb opt
(lldb) target create "opt"
Current executable set to '/home/cristianrichie/276/reduce/opt' (x86_64).
(lldb) b 13
Breakpoint 1: where = opt`main + 32 [inlined] a at a.c:13:1, address =
0x0000000000401160
(lldb) r
Process 2122 launched: '/home/cristianrichie/276/reduce/opt' (x86_64)
Process 2122 stopped
* thread #1, name = 'opt', stop reason = breakpoint 1.1
frame #0: 0x0000000000401160 opt`main [inlined] a at a.c:13:1
10 j = 0;
11 for (; j < 7; j++)
12 {
-> 13 test_nop();
14 test_support_3073(l_287, l_326, l_341, l_342, l_343, l_363, l_387,
l_412, l_413, l_436, i, j);
15 }
16 }
(lldb) frame var
(int) i = 0
(int) j = 0
(lldb) frame var l_287
error: no variable named 'l_287' found in this frame
(lldb) frame var l_326
error: no variable named 'l_326' found in this frame
(lldb) frame var l_341
error: no variable named 'l_341' found in this frame
(lldb) frame var l_342
error: no variable named 'l_342' found in this frame
(lldb) frame var l_343
error: no variable named 'l_343' found in this frame
(lldb) frame var l_363
error: no variable named 'l_363' found in this frame
(lldb) frame var l_387
error: no variable named 'l_387' found in this frame
(lldb) frame var l_412
error: no variable named 'l_412' found in this frame
(lldb) frame var l_413
error: no variable named 'l_413' found in this frame</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>