Convert frame unwinders to use the current frame and

"struct value".

	* frame.c (frame_debug): Make global.
	(get_frame_id): Pass this frame to unwinder routines.
	(frame_pc_unwind): Remove unused unwind->prev_pc support.
	(do_frame_register_read): Do not discard the return value of
	frame_register_read.
	(frame_register_unwind): Remove debug messages.  Use
	frame_unwind_register_value.
	(frame_unwind_register_value, get_frame_register_value): New
	functions.
	(create_new_frame, get_frame_base_address, get_frame_locals_address)
	(get_frame_args_address, get_frame_type): Pass this frame to
	unwinder routines.
	(frame_cleanup_after_sniffer, frame_prepare_for_sniffer): New
	functions.
	* frame.h: Update comments.
	(frame_debug, frame_unwind_register_value, get_frame_register_value)
	(frame_prepare_for_sniffer): Declare.
	* frame-unwind.h: Update comments and parameter names.
	(default_frame_sniffer): Declare.
	(frame_prev_register_ftype): Return a struct value *.
	(struct frame_unwind): Remove prev_pc member.
	(frame_unwind_sniffer_ftype, frame_unwind_append_sniffer): Delete.
	(frame_unwind_append_unwinder, frame_unwind_got_optimized)
	(frame_unwind_got_register, frame_unwind_got_memory)
	(frame_unwind_got_constant, frame_unwind_got_address): Declare.
	* frame-base.h: Update comments and parameter names.
	* valops.c (value_fetch_lazy): Use get_frame_register_value.  Iterate
	if necessary.  Add debugging output.
	* sentinel-frame.c (sentinel_frame_prev_register)
	(sentinel_frame_this_id): Update for new signature.
	(sentinel_frame_prev_pc): Delete.
	(sentinel_frame_unwinder): Remove prev_pc.
	* ia64-tdep.c (ia64_libunwind_frame_unwind): Do not initialize
	prev_pc.
	* libunwind-frame.c (libunwind_frame_unwind): Likewise.
	* frame-unwind.c (struct frame_unwind_table_entry): Remove sniffer.
	(frame_unwind_append_sniffer): Delete.
	(frame_unwind_append_unwinder): New function.
	(frame_unwind_find_by_frame): Take this frame.  Only use sniffers
	from unwinders.  Use frame_prepare_for_sniffer.
	(default_frame_sniffer, frame_unwind_got_optimized)
	(frame_unwind_got_register, frame_unwind_got_memory)
	(frame_unwind_got_constant, frame_unwind_got_address): New functions.
	* dummy-frame.c (dummy_frame_sniffer): Use gdbarch_dummy_id.
	(dummy_frame_prev_register, dummy_frame_this_id): Update for new
	signature.
	* gdbarch.sh: Replace unwind_dummy_id with dummy_id.
	* gdbarch.c, gdbarch.c: Regenerated.
	* frame-base.c (default_frame_base_address)
	(default_frame_locals_address, default_frame_args_address): Update
	for new signature.
	(frame_base_find_by_frame): Pass this frame to unwinder routines.
	* infcall.c (call_function_by_hand): Update comments.
	* Makefile.in (frame-unwind.o): Update dependencies.

	* gdbint.texinfo (Stack Frames): New chapter.
	(Algorithms): Move Frames text to the new chapter.
	(Target Conditionals): Delete SAVE_DUMMY_FRAME_TOS.  Document
	gdbarch_dummy_id instead of gdbarch_unwind_dummy_id.

gdb/dummy-frame.c

@@ -39,7 +39,7 @@ struct dummy_frame
 {
   struct dummy_frame *next;
   /* This frame's ID.  Must match the value returned by
-     gdbarch_unwind_dummy_id.  */
+     gdbarch_dummy_id.  */
   struct frame_id id;
   /* The caller's regcache.  */
   struct regcache *regcache;
@@ -124,7 +124,7 @@ struct dummy_frame_cache
 
 int
 dummy_frame_sniffer (const struct frame_unwind *self,
-		     struct frame_info *next_frame,
+		     struct frame_info *this_frame,
 		     void **this_prologue_cache)
 {
   struct dummy_frame *dummyframe;
@@ -141,12 +141,9 @@ dummy_frame_sniffer (const struct frame_unwind *self,
   /* Don't bother unles there is at least one dummy frame.  */
   if (dummy_frame_stack != NULL)
     {
-      /* Use an architecture specific method to extract the prev's
-	 dummy ID from the next frame.  Note that this method uses
-	 frame_register_unwind to obtain the register values needed to
-	 determine the dummy frame's ID.  */
-      this_id = gdbarch_unwind_dummy_id (get_frame_arch (next_frame), 
-					 next_frame);
+      /* Use an architecture specific method to extract this frame's
+	 dummy ID, assuming it is a dummy frame.  */
+      this_id = gdbarch_dummy_id (get_frame_arch (this_frame), this_frame);
 
       /* Use that ID to find the corresponding cache entry.  */
       for (dummyframe = dummy_frame_stack;
@@ -170,43 +167,37 @@ dummy_frame_sniffer (const struct frame_unwind *self,
 /* Given a call-dummy dummy-frame, return the registers.  Here the
    register value is taken from the local copy of the register buffer.  */
 
-static void
-dummy_frame_prev_register (struct frame_info *next_frame,
+static struct value *
+dummy_frame_prev_register (struct frame_info *this_frame,
 			   void **this_prologue_cache,
-			   int regnum, int *optimized,
-			   enum lval_type *lvalp, CORE_ADDR *addrp,
-			   int *realnum, gdb_byte *bufferp)
+			   int regnum)
 {
-  /* The dummy-frame sniffer always fills in the cache.  */
   struct dummy_frame_cache *cache = (*this_prologue_cache);
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  struct value *reg_val;
+
+  /* The dummy-frame sniffer always fills in the cache.  */
   gdb_assert (cache != NULL);
 
   /* Describe the register's location.  Generic dummy frames always
      have the register value in an ``expression''.  */
-  *optimized = 0;
-  *lvalp = not_lval;
-  *addrp = 0;
-  *realnum = -1;
+  reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
 
-  /* 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->prev_regcache, regnum, bufferp);
-    }
+  /* 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->prev_regcache, regnum,
+			value_contents_writeable (reg_val));
+  return reg_val;
 }
 
-/* Assuming that THIS frame is a dummy (remember, the NEXT and not
-   THIS frame is passed in), return the ID of THIS frame.  That ID is
+/* Assuming that THIS frame is a dummy, return the ID of THIS frame.  That ID is
    determined by examining the NEXT frame's unwound registers using
-   the method unwind_dummy_id().  As a side effect, THIS dummy frame's
+   the method dummy_id().  As a side effect, THIS dummy frame's
    dummy cache is located and and saved in THIS_PROLOGUE_CACHE.  */
 
 static void
-dummy_frame_this_id (struct frame_info *next_frame,
+dummy_frame_this_id (struct frame_info *this_frame,
 		     void **this_prologue_cache,
 		     struct frame_id *this_id)
 {