RE: Is this a bug or as designed?

["Pierre Muller" <muller at ics dot u-strasbg dot fr>]

This is a limitation of windows native GDB 6.8
I wrote two patches that should solve that issue
for next release if they are accepted.

http://sourceware.org/ml/gdb-patches/2009-02/msg00194.html
and
http://sourceware.org/ml/gdb-patches/2009-02/msg00206.html

  If you are willing to test these out,
you will need to get GDB cvs HEAD source
and apply the two patches above.


Pierre Muller
Pascal language support maintainer for GDB



> -----Message d'origine-----
> De?: gdb-owner@sourceware.org [mailto:gdb-owner@sourceware.org] De la
> part de Amker.Cheng
> Envoyé?: Wednesday, February 11, 2009 12:59 PM
> À?: gdb@sourceware.org
> Objet?: Is this a bug or as designed?
> 
> Hi All:
>   I got a problem about the behavior of gdb 6.8.
>   When remote debugging win32 inferior with gdb and gdbserver(both
> running on the same machine),
> I found that gdb always missing watchpoints. just like following
> outputs:
> 
> ----------------start here
> GNU gdb 6.8
> 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 "i386-pc-cygwin".
> (gdb) file a.exe
> Reading symbols from /cygdrive/e/work/gdb/native-
> target/bin/a.exe...done.
> (gdb) target remote  :2345
> Remote debugging using :2345
> [New Thread 1980]
> Reading symbols from /cygdrive/c/WINDOWS/system32/ntdll.dll...done.
> Loaded symbols for /cygdrive/c/WINDOWS/system32/ntdll.dll
> Reading symbols from /cygdrive/c/WINDOWS/system32/kernel32.dll...done.
> Loaded symbols for /cygdrive/c/WINDOWS/system32/kernel32.dll
> Reading symbols from /usr/bin/cygwin1.dll...done.
> Loaded symbols for /usr/bin/cygwin1.dll
> Reading symbols from /cygdrive/c/WINDOWS/system32/advapi32.dll...done.
> Loaded symbols for /cygdrive/c/WINDOWS/system32/advapi32.dll
> Reading symbols from /cygdrive/c/WINDOWS/system32/rpcrt4.dll...done.
> Loaded symbols for /cygdrive/c/WINDOWS/system32/rpcrt4.dll
> 0x7c921231 in ntdll!DbgUiConnectToDbg () from
> /cygdrive/c/WINDOWS/system32/ntdll.dll
> (gdb) awatch b
> Hardware access (read/write) watchpoint 1: b
> (gdb) c
> Continuing.
> 
> Program exited normally.
> (gdb) q
> ------------------cut here
> 
> 
> 
> According to above output, gdb just let inferior run to end normally,
> although it said
> hardware watchpoint was set successfully.
> 
> I checked the remotelogfile and found there is no "Z" packets at all.
> Further more, I
> think there is something wrong when handling hardware watchpoint in
> gdbserver for win32,
> because the debug register is not set at all in gdbserver.
> 
> BTW It is sure that there are access to b in the inferior program and
> There is no such problem with native debug with GDB under win32+cygwin.
> 
> Thanks for help!
> Regards.