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pending/2565: Re: 'p siginfo->si_addr' doesn't work anymore
- From: Pedro Alves <pedro at codesourcery dot com>
- To: gdb-gnats at sources dot redhat dot com
- Date: Wed, 10 Dec 2008 15:53:03 +0000
- Subject: pending/2565: Re: 'p siginfo->si_addr' doesn't work anymore
- References: <20081210154324.6944.qmail@sourceware.org>
>Number: 2565
>Category: pending
>Synopsis: Re: 'p siginfo->si_addr' doesn't work anymore
>Confidential: yes
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: change-request
>Submitter-Id: unknown
>Arrival-Date: Wed Dec 10 15:58:01 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:
>Release:
>Organization:
>Environment:
>Description:
Test inline:
#include <signal.h>
#include <string.h>
int
main (int argc, char **argv)
{
struct siginfo info; /* make sure it's not related to var name equal type name. */
struct siginfo siginfo; /* var vs ... */
struct siginfo *siginfo_p = &siginfo; /* ... pointer */
return 0;
}
Some more info:
(gdb) info macro si_addr
Defined at /usr/include/bits/siginfo.h:122
included at /usr/include/signal.h:212
included at /home/pedro/gdb/tests/siginfo_exp.c:1
#define si_addr _sifields._sigfault.si_addr
(gdb)
>/home/pedro/gdb/baseline/build/gdb/gdb ./siginfo_exp
GNU gdb (GDB) 6.8.50.20081210-cvs
Copyright (C) 2008 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. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
(gdb) start
Temporary breakpoint 1 at 0x400460: file siginfo_exp.c, line 9.
Starting program: /home/pedro/gdb/tests/siginfo_exp
Temporary breakpoint 1, main (argc=1, argv=0x7fffffffe408) at siginfo_exp.c:9
9 struct siginfo *siginfo_p = &siginfo; /* ... pointer */
(gdb) p siginfo
$1 = {si_signo = 1, si_errno = 0, si_code = 0, _sifields = {_pad = {1, 0, 0, 0, 0, 0, 0, 0, 0, 1, -134241448, 32767,
-7296, 32767, -134242304, 32767, 4195034, 0, 0, 0, 1, 0, -139464905, 32767, 0, 0, 134090501, 191}, _kill = {
si_pid = 1, si_uid = 0}, _timer = {si_tid = 1, si_overrun = 0, si_sigval = {sival_int = 0, sival_ptr = 0x0}},
_rt = {si_pid = 1, si_uid = 0, si_sigval = {sival_int = 0, sival_ptr = 0x0}}, _sigchld = {si_pid = 1,
si_uid = 0, si_status = 0, si_utime = 0, si_stime = 0}, _sigfault = {si_addr = 0x1}, _sigpoll = {si_band = 1,
si_fd = 0}}}
(gdb) p siginfo_p->si_addr
There is no member named .
(gdb) macro expand siginfo_p->si_addr
expands to: siginfo_p->_sifields._sigfault.si_addr
Manual expansion succeeds, but, (guessing) it seems that when evaluating, GDB is trying to further re-expand the si_addr member of _sigfault, as a macro.
Trying the manually expanded form is no help, since GDB tries to expand si_addr, and doesn't fallback to a real member:
(gdb) p siginfo_p->_sifields._sigfault.si_addr
There is no member named _sifields.
Interestingly, macro expansion when using the '.' operator
instead of the '->' operator behaves differently:
(gdb) p siginfo.si_addr
There is no member named .
(gdb) macro expand siginfo.si_addr
expands to: siginfo.si_addr
Making sure it's not related to var named siginfo and type named siginfo; printing through a variable, with '.' operator:
(gdb) p info.si_addr
There is no member named .
(gdb) macro expand info.si_addr
expands to: info.si_addr
Evaluation seems to have expanded, and hit the same bug as before, but manual expansion fails to even expand the first si_addr.
Making sure its not related to the var type, but to the operator used:
(gdb) p siginfo_p.si_addr
There is no member named .
(gdb) macro expand siginfo_p.si_addr
expands to: siginfo_p.si_addr
This is a regression against 6.8:
(gdb) p siginfo.si_addr
$1 = (void *) 0x1
(gdb) macro expand siginfo_p->si_addr
expands to: siginfo_p->_sifields._sigfault.si_addr
(gdb) p siginfo_p->si_addr
$2 = (void *) 0x1
(gdb)
Although macro expanding with the '.' operator was broken already:
(gdb) macro expand siginfo.si_addr
expands to: siginfo.si_addr
>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted: