[commit] allow to set length for remote hw watchpoints (e.g. for Valgrind gdbserver)

[Philippe Waroquiers <philippe dot waroquiers at skynet dot be>]

After my addition in write after approval, and previous
approval of this patch, committed the below.
(regression tested in native and gdbserver on f12/x86, debian5/amd64,
no regression identified).

Thanks

Index: gdb/ChangeLog
===================================================================
RCS file: /cvs/src/src/gdb/ChangeLog,v
retrieving revision 1.13227
diff -c -p -r1.13227 ChangeLog
*** gdb/ChangeLog	26 Jul 2011 19:39:57 -0000	1.13227
--- gdb/ChangeLog	26 Jul 2011 20:50:58 -0000
***************
*** 1,3 ****
--- 1,11 ----
+ 2011-07-26  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
+ 
+ 	* remote.c (remote_region_ok_for_hw_watchpoint): New function.
+ 	(remote_hw_watchpoint_length_limit): New variable.
+ 	(_initialize_remote) add set,show cmds for this new variable.
+ 	* gdb.texinfo: document these new commands.
+ 	* NEWS: Mention these new commands.
+ 
  2011-07-26  Pedro Alves  <pedro@codesourcery.com>
  
  	* breakpoint.c (works_in_software_mode_watchpoint): Also return
Index: gdb/NEWS
===================================================================
RCS file: /cvs/src/src/gdb/NEWS,v
retrieving revision 1.445
diff -c -p -r1.445 NEWS
*** gdb/NEWS	26 Jul 2011 15:24:02 -0000	1.445
--- gdb/NEWS	26 Jul 2011 20:51:00 -0000
***************
*** 3,8 ****
--- 3,18 ----
  
  *** Changes since GDB 7.3
  
+ * GDB has two new commands: "set remote
hardware-watchpoint-length-limit"
+   and "show remote hardware-watchpoint-length-limit".  These allows to
+   set or show the maximum length limit (in bytes) of a remote
+   target hardware watchpoint.
+ 
+   This allows e.g. to use "unlimited" hardware watchpoints with the
+   gdbserver integrated in Valgrind version >= 3.7.0.  Such Valgrind
+   watchpoints are slower than real hardware watchpoints but are
+   significantly faster than gdb software watchpoints.
+ 
  * Python scripting
  
    ** The "maint set python print-stack on|off" command has been
Index: gdb/remote.c
===================================================================
RCS file: /cvs/src/src/gdb/remote.c,v
retrieving revision 1.458
diff -c -p -r1.458 remote.c
*** gdb/remote.c	25 Jul 2011 11:24:44 -0000	1.458
--- gdb/remote.c	26 Jul 2011 20:51:01 -0000
*************** remote_remove_watchpoint (CORE_ADDR addr
*** 7763,7771 ****
--- 7763,7785 ----
  
  
  int remote_hw_watchpoint_limit = -1;
+ int remote_hw_watchpoint_length_limit = -1;
  int remote_hw_breakpoint_limit = -1;
  
  static int
+ remote_region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
+ {
+   if (remote_hw_watchpoint_length_limit == 0)
+     return 0;
+   else if (remote_hw_watchpoint_length_limit < 0)
+     return 1;
+   else if (len <= remote_hw_watchpoint_length_limit)
+     return 1;
+   else
+     return 0;
+ }
+ 
+ static int
  remote_check_watch_resources (int type, int cnt, int ot)
  {
    if (type == bp_hardware_breakpoint)
*************** Specify the serial device it is connecte
*** 10356,10361 ****
--- 10370,10377 ----
    remote_ops.to_can_use_hw_breakpoint = remote_check_watch_resources;
    remote_ops.to_insert_hw_breakpoint = remote_insert_hw_breakpoint;
    remote_ops.to_remove_hw_breakpoint = remote_remove_hw_breakpoint;
+   remote_ops.to_region_ok_for_hw_watchpoint
+      = remote_region_ok_for_hw_watchpoint;
    remote_ops.to_insert_watchpoint = remote_insert_watchpoint;
    remote_ops.to_remove_watchpoint = remote_remove_watchpoint;
    remote_ops.to_kill = remote_kill;
*************** Specify a negative limit for unlimited."
*** 10751,10756 ****
--- 10767,10781 ----
  					   number of target hardware
  					   watchpoints is %s.  */
  			    &remote_set_cmdlist, &remote_show_cmdlist);
+   add_setshow_zinteger_cmd ("hardware-watchpoint-length-limit",
no_class,
+ 			    &remote_hw_watchpoint_length_limit, _("\
+ Set the maximum length (in bytes) of a target hardware watchpoint."),
_("\
+ Show the maximum length (in bytes) of a target hardware watchpoint."),
_("\
+ Specify a negative limit for unlimited."),
+ 			    NULL, NULL, /* FIXME: i18n: The maximum
+                                            length (in bytes) of a
target
+                                            hardware watchpoint is %s.
*/
+ 			    &remote_set_cmdlist, &remote_show_cmdlist);
    add_setshow_zinteger_cmd ("hardware-breakpoint-limit", no_class,
  			    &remote_hw_breakpoint_limit, _("\
  Set the maximum number of target hardware breakpoints."), _("\
Index: gdb/doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.850
diff -c -p -r1.850 gdb.texinfo
*** gdb/doc/gdb.texinfo	26 Jul 2011 16:59:23 -0000	1.850
--- gdb/doc/gdb.texinfo	26 Jul 2011 20:51:08 -0000
*************** responses.
*** 16655,16660 ****
--- 16655,16672 ----
  Restrict @value{GDBN} to using @var{limit} remote hardware breakpoint
or
  watchpoints.  A limit of -1, the default, is treated as unlimited.
  
+ @cindex limit hardware watchpoints length
+ @cindex remote target, limit watchpoints length
+ @anchor{set remote hardware-watchpoint-length-limit}
+ @item set remote hardware-watchpoint-length-limit @var{limit}
+ Restrict @value{GDBN} to using @var{limit} bytes for the maximum
length of
+ a remote hardware watchpoint.  A limit of -1, the default, is treated
+ as unlimited.
+ 
+ @item show remote hardware-watchpoint-length-limit
+ Show the current limit (in bytes) of the maximum length of
+ a remote hardware watchpoint.
+ 
  @item set remote exec-file @var{filename}
  @itemx show remote exec-file
  @anchor{set remote exec-file}