2003-01-27 Andrew Cagney <ac131313@redhat.com>

	* sentinel-frame.h, sentinel-frame.c: New files.
	* Makefile.in (frame.o): Update dependencies.
	(SFILES): Add sentinel-frame.c.
	(sentinel_frame_h): Define.
	(COMMON_OBS): Add sentinel-frame.o.
	(sentinel-frame.o): Specify dependencies.
	* frame.c: Include "sentinel-frame.h".
	(frame_register_unwind): Rewrite assuming that there is always a a
	->next frame.
	(frame_register, generic_unwind_get_saved_register): Ditto.
	(frame_read_unsigned_register, frame_read_signed_register): Ditto.
	(create_sentinel_frame, unwind_to_current_frame): New functions.
	(get_current_frame): Rewrite using create_sentinel_frame and
	unwind_to_current_frame.  When possible, always create a frame.
	(create_new_frame): Set next to the sentinel frame.
	(get_next_frame): Rewrite.  Don't go below the level 0 frame.
	(deprecated_update_frame_pc_hack): Update the next frame's PC and
	ID cache when necessary.
	(frame_saved_regs_id_unwind): Use frame_relative_level.
	(deprecated_generic_get_saved_register): Use frame_relative_level,
	get_frame_saved_regs, get_frame_pc, get_frame_base and
	get_next_frame.
	(frame_saved_regs_register_unwind): Use get_frame_saved_regs and
	frame_register.

1 files changed, 113 insertions, 0 deletions

diff --git a/gdb/sentinel-frame.c b/gdb/sentinel-frame.c
new file mode 100644
index 00000000000..fe11d8a6f43
--- /dev/null
+++ b/gdb/sentinel-frame.c
@@ -0,0 +1,113 @@
+/* Code dealing with register stack frames, for GDB, the GNU debugger.
+
+   Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
+   1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 Free Software
+   Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+
+#include "defs.h"
+#include "regcache.h"
+#include "sentinel-frame.h"
+#include "inferior.h"
+#include "frame-unwind.h"
+
+struct frame_unwind_cache
+{
+  struct regcache *regcache;
+};
+
+void *
+sentinel_frame_cache (struct regcache *regcache)
+{
+  struct frame_unwind_cache *cache = 
+    FRAME_OBSTACK_ZALLOC (struct frame_unwind_cache);
+  cache->regcache = regcache;
+  return cache;
+}
+
+/* Here the register value is taken direct from the register cache.  */
+
+void
+sentinel_frame_register_unwind (struct frame_info *frame,
+				void **unwind_cache,
+				int regnum, int *optimized,
+				enum lval_type *lvalp, CORE_ADDR *addrp,
+				int *realnum, void *bufferp)
+{
+  struct frame_unwind_cache *cache = *unwind_cache;
+  /* Describe the register's location.  A reg-frame maps all registers
+     onto the corresponding hardware register.  */
+  *optimized = 0;
+  *lvalp = lval_register;
+  *addrp = REGISTER_BYTE (regnum);
+  *realnum = regnum;
+
+  /* If needed, find and return the value of the register.  */
+  if (bufferp != NULL)
+    {
+      /* Return the actual value.  */
+      /* Use the regcache_cooked_read() method so that it, on the fly,
+         constructs either a raw or pseudo register from the raw
+         register cache.  */
+      regcache_cooked_read (cache->regcache, regnum, bufferp);
+    }
+}
+
+CORE_ADDR
+sentinel_frame_pc_unwind (struct frame_info *frame,
+			  void **cache)
+{
+  /* FIXME: cagney/2003-01-08: This should be using a per-architecture
+     method that doesn't suffer from DECR_PC_AFTER_BREAK problems.
+     Such a method would take unwind_cache, regcache and stop reason
+     parameters.  */
+  return read_pc ();
+}
+
+void
+sentinel_frame_id_unwind (struct frame_info *frame,
+			  void **cache,
+			  struct frame_id *id)
+{
+  /* FIXME: cagney/2003-01-08: This should be using a per-architecture
+     method that doesn't suffer from DECR_PC_AFTER_BREAK problems.
+     Such a method would take unwind_cache, regcache and stop reason
+     parameters.  */
+  id->base = read_fp ();
+  id->pc = read_pc ();
+}
+
+static void
+sentinel_frame_pop (struct frame_info *frame,
+		    void **cache,
+		    struct regcache *regcache)
+{
+  internal_error (__FILE__, __LINE__, "Function sentinal_frame_pop called");
+}
+
+const struct frame_unwind sentinel_frame_unwinder =
+{
+  sentinel_frame_pop,
+  sentinel_frame_pc_unwind,
+  sentinel_frame_id_unwind,
+  sentinel_frame_register_unwind
+};
+
+const struct frame_unwind *const sentinel_frame_unwind = &sentinel_frame_unwinder;