macros/2564: 'p siginfo->si_addr' doesn't work anymore

macros/2564: 'p siginfo->si_addr' doesn't work anymore

[pedro]

>Number:         2564
>Category:       macros
>Synopsis:       'p siginfo->si_addr' doesn't work anymore
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Wed Dec 10 15:48:04 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     pedro@codesourcery.com
>Release:        gdb HEAD 20081210
>Organization:
>Environment:
Linux orlando 2.6.24-21-generic #1 SMP Tue Oct 21 23:09:30 UTC 2008 x86_64 GNU/Linux
>Description:
Trying to 'print siginfo_p->si_addr' in the attached test fails with:

 (gdb) p siginfo_p->si_addr
 There is no member named .

Although si_addr is a macro defined as:
#define si_addr _sifields._sigfault.si_addr

This worked on 6.8.

And struct siginfo does have those members.
>How-To-Repeat:
Build with gcc -g3 for the extra macro info.

b main; run; next;

 (gdb) p siginfo_p->si_addr
 There is no member named .
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
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pending/2565: Re: 'p siginfo->si_addr' doesn't work anymore

[Pedro Alves]

>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:

Re: pending/2565: Re: 'p siginfo->si_addr' doesn't work anymore

[tromey]

Synopsis: Re: 'p siginfo->si_addr' doesn't work anymore

State-Changed-From-To: open->closed
State-Changed-By: tromey
State-Changed-When: Wed Dec 10 18:16:16 2008
State-Changed-Why:
    Duplicate of PR 2564

http://sourceware.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gdb&pr=2565