[PATCH 2/2] Notice architecture changes even when the register window is not open.

The register cache can be accessed through the TCL proc "gdb_reginfo",
which can be called from anywhere, there's currently only one other
caller in "actiondlg.tcl", but more callers could easily be added.  I
believe that currently any caller to gdb_reginfo needs to (a) know if
they are accessing the reg-cache, and (b) if they are listen for arch
changed events and update the reg-cache.  I think this a bad situation
to be in as, the reg-cache would ideally be hidden from the user of
"gdb_reginfo", and secondly, we only really need to update the reg-cache
once per architecture change, not many times, which could happen if many
users are all trying to keep the reg-cache upto date.

Phew! So, the patch below moves the call to "gdb_reg_arch_changed" into
the top-level tcl event handler, we need to ensure that it gets called
before any of the event-handling windows see the architecture change
event as they might access the reg-cache.  I could in-theory have moved
the call to "gdb_reg_arch_changed" into the top-level window event
handler, I didn't do this for two reasons, (1) I didn't know if the top
level window always exists, though I suspect it does, but really (2) I
didn't know if there was any control on the order the windows receive
the events...

Anyway, let me know what you think, all feedback welcome.

Thanks,
Andrew

gdb/gdbtk/ChangeLog

2013-09-05  Andrew Burgess  <[email protected]>

	* library/interface.tcl (gdbtk_tcl_architecture_changed): Add call
	to gdb_reg_arch_changed.
	* library/regwin.itb (arch_changed): Remove call to
	gdb_reg_arch_changed.

Index: ./gdb/gdbtk/library/interface.tcl
===================================================================
RCS file: /cvs/src/src/gdb/gdbtk/library/interface.tcl,v
retrieving revision 1.60
diff -u -p -r1.60 interface.tcl
--- ./gdb/gdbtk/library/interface.tcl	9 Oct 2009 01:23:55 -0000	1.60
+++ ./gdb/gdbtk/library/interface.tcl	5 Sep 2013 14:19:53 -0000
@@ -1815,6 +1815,9 @@ proc initialize_gdbtk {} {
 # The architecture changed. Inform the UI.
 proc gdbtk_tcl_architecture_changed {} {
   set e [ArchChangedEvent \#auto]
+  # First perform global actions as a result of the architecture change.
+  gdb_reg_arch_changed $e 
+  # Now dispatch to all the other even handlers.
   GDBEventHandler::dispatch $e
   delete object $e
 }
Index: ./gdb/gdbtk/library/regwin.itb
===================================================================
RCS file: /cvs/src/src/gdb/gdbtk/library/regwin.itb,v
retrieving revision 1.30
diff -u -p -r1.30 regwin.itb
--- ./gdb/gdbtk/library/regwin.itb	25 May 2012 10:34:32 -0000	1.30
+++ ./gdb/gdbtk/library/regwin.itb	5 Sep 2013 14:19:53 -0000
@@ -932,9 +932,6 @@ itcl::body RegWin::_select_group {} {
 # ------------------------------------------------------------------
 itcl::body RegWin::arch_changed {event} {
 
-  # Update internal register caches
-  gdb_reg_arch_changed
-
   # Relayout the table
   _layout_table