https://bugs.llvm.org/show_bug.cgi?id=45944
Bug ID: 45944
Summary: LLDB print wrong value for a parameter at Og
Product: lldb
Version: unspecified
Hardware: PC
OS: Linux
Status: NEW
Keywords: wrong-debug
Severity: enhancement
Priority: P
Component: All Bugs
Assignee: lldb-dev@lists.llvm.org
Reporter: massare...@diag.uniroma1.it
CC: ditali...@apple.com, jdevliegh...@apple.com,
llvm-b...@lists.llvm.org
LLDB show a wrong value at line 10 for parameter val in function ff.
$ cat a.c
typedef int uint32_t;
uint32_t a[256];
uint32_t c, e, f, g, h;
void d(b) {
c = a[(c ^ b) & 255];
}
void ff(uint32_t val) {
d(val >> 8);
c = a[(c ^ 24) & 255];
}
int main() {
ff(47656);
}
$ clang -v
clang version 11.0.0 (https://github.com/llvm/llvm-project.git
c25b20c0f6c13d68dbc2e185764082d61ae4a132)
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
Found candidate GCC installation:
/usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/11.0.0
Selected GCC installation: /usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/11.0.0
Candidate multilib: .;@m64
Selected multilib: .;@m64
$ lldb -v
lldb version 11.0.0
clang revision c25b20c0f6c13d68dbc2e185764082d61ae4a132
llvm revision c25b20c0f6c13d68dbc2e185764082d61ae4a132
$ gdb -v
GNU gdb (Ubuntu 8.1-0ubuntu3.2) 8.1.0.20180409-git
$ clang -Og -g -o opt amod.c
$ lldb opt
(lldb) b ff
Breakpoint 1: where = opt`ff + 1 at amod.c:9:9, address = 0x004004a1
(lldb) r
Process 60 launched: 'opt' (x86_64)
Process 60 stopped
* thread #1, name = 'opt', stop reason = breakpoint 1.1
frame #0: 0x004004a1 opt`ff(val=47656) at amod.c:9:9
6}
7
8void ff(uint32_t val) {
-> 9 d(val >> 8);
10 c = a[(c ^ 24) & 255];
11 }
12
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x00400484 opt`d(b=186) at amod.c:5:11
2uint32_t a[256];
3uint32_t c, e, f, g, h;
4void d(b) {
-> 5 c = a[(c ^ b) & 255];
6}
7
8void ff(uint32_t val) {
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x0040049a opt`d(b=186) at amod.c:6:1
3uint32_t c, e, f, g, h;
4void d(b) {
5 c = a[(c ^ b) & 255];
-> 6}
7
8void ff(uint32_t val) {
9 d(val >> 8);
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x004004a9 opt`ff(val=186) at amod.c:10:10
7
8void ff(uint32_t val) {
9 d(val >> 8);
-> 10 c = a[(c ^ 24) & 255];
11 }
12
13 int main() {
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x004004c1 opt`ff(val=186) at amod.c:11:1
8void ff(uint32_t val) {
9 d(val >> 8);
10 c = a[(c ^ 24) & 255];
-> 11 }
12
13 int main() {
14 ff(47656);
(lldb) s
Process 60 stopped
* thread #1, name = 'opt', stop reason = step in
frame #0: 0x004004db opt`main at amod.c:15:1
12
13 int main() {
14 ff(47656);
-> 15 }
(lldb) s
$ gdb opt
(gdb) b ff
Breakpoint 1 at 0x4004a1: file amod.c, line 9.
(gdb) r
Starting program: opt
Breakpoint 1, ff (val=val@entry=47656) at amod.c:9
9 d(val >> 8);
(gdb) s
d (b=186) at amod.c:5
5 c = a[(c ^ b) & 255];
(gdb) s
d (b=186) at amod.c:6
6 }
(gdb) s
ff (val=val@entry=47656) at amod.c:10
10c = a[(c ^ 24) & 255];
(gdb) p val
$1 = 47656
(gdb) s
11 }
(gdb) s
main () at amod.c:15
15 }
(gdb) s
--
You are receiving this mail because:
You are the assignee for the bug.___
lldb-dev mailing list
lldb-dev@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
