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* [Bug symtab/26061] New: Wrong debug info for argc at -O2
@ 2020-05-29 12:30 yangyibiao at hust dot edu.cn
  2020-05-29 15:47 ` [Bug symtab/26061] " yangyibiao at hust dot edu.cn
                   ` (8 more replies)
  0 siblings, 9 replies; 10+ messages in thread
From: yangyibiao at hust dot edu.cn @ 2020-05-29 12:30 UTC (permalink / raw)
  To: gdb-prs

https://sourceware.org/bugzilla/show_bug.cgi?id=26061

            Bug ID: 26061
           Summary: Wrong debug info for argc at -O2
           Product: gdb
           Version: HEAD
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: symtab
          Assignee: unassigned at sourceware dot org
          Reporter: yangyibiao at hust dot edu.cn
  Target Milestone: ---

Created attachment 12577
  --> https://sourceware.org/bugzilla/attachment.cgi?id=12577&action=edit
a.out

$ gcc --version
gcc (GCC) 10.0.1 20200419 (experimental)
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

yibiao:~/Debugger$ gdb --version
GNU gdb (GDB) 10.0.50.20200517-git
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.


Consider test-case:
...
$ cat small.c
#include <stdio.h>

int main(int argc, char **argv) {
  char buf[6];
  char c[] = "abc";
  sprintf(buf, (char *)c, 1);

  return 0;
}
...

$ gcc -O2 -g small.c; gdb -q a.out
Reading symbols from a.out...
(gdb) b main
Breakpoint 1 at 0x401040: file small.c, line 5.
(gdb) r
Starting program: /home/yibiao/Debugger/a.out 

Breakpoint 1, main (argc=1, argv=0x7fffffffdff8) at small.c:5
5         char c[] = "abc";
(gdb) info args argc
argc = 1
(gdb) step
6         sprintf(buf, (char *)c, 1);
(gdb) info args argc
argc = -8454
(gdb) 


/**************************************
We can find that at line 5, the value of argc is 1. When stepping to line 6,
the value of argc is changed to -8454. When stepping with stepi, the value of
argc is correct.

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^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2022-11-09  2:42 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-29 12:30 [Bug symtab/26061] New: Wrong debug info for argc at -O2 yangyibiao at hust dot edu.cn
2020-05-29 15:47 ` [Bug symtab/26061] " yangyibiao at hust dot edu.cn
2020-05-30 17:03 ` tankut.baris.aktemur at intel dot com
2020-05-31  0:39 ` yangyibiao at hust dot edu.cn
2020-12-29  6:38 ` yangyibiao at outlook dot com
2022-05-29  2:24 ` yangyibiao at outlook dot com
2022-11-08  3:34 ` yangyibiao at nju dot edu.cn
2022-11-08  8:13 ` sam at gentoo dot org
2022-11-09  2:28 ` tromey at sourceware dot org
2022-11-09  2:42 ` yangyibiao at nju dot edu.cn

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