[patch] Code cleanup: bpstat_alloc calling semantics standardization

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

this is just for the second patch I am going to send in a minute.  I would not
patch it standalone but I could not manage to code anything on top of it.

No regressions on {x86_64,x86_64-m32,i686}-fedora14snapshot-linux-gnu.
(Tested together with the second patch.)


Thanks,
Jan


2010-08-11  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Code cleanup.
	* breakpoint.c (bpstat_alloc): Remove unused prototype.
	(bpstat_alloc): Change parameters cbs to bs_link_pointer.  Adjust the
	code.
	(bpstat_stop_status): Change root_bs into bs_head and bs_link.  Adjust
	calls of bpstat_alloc.  Remove explicit bs chain termination.

--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -135,8 +135,6 @@ static void watchpoints_info (char *, int);
 
 static int breakpoint_1 (int, int, int (*) (const struct breakpoint *));
 
-static bpstat bpstat_alloc (const struct bp_location *, bpstat);
-
 static int breakpoint_cond_eval (void *);
 
 static void cleanup_executing_breakpoints (void *);
@@ -3442,15 +3440,17 @@ breakpoint_cond_eval (void *exp)
   return i;
 }
 
-/* Allocate a new bpstat and chain it to the current one.  */
+/* Allocate a new bpstat.  Link it to the FIFO list by BS_LINK_POINTER.  */
 
 static bpstat
-bpstat_alloc (const struct bp_location *bl, bpstat cbs /* Current "bs" value */ )
+bpstat_alloc (const struct bp_location *bl, bpstat **bs_link_pointer)
 {
   bpstat bs;
 
   bs = (bpstat) xmalloc (sizeof (*bs));
-  cbs->next = bs;
+  bs->next = NULL;
+  **bs_link_pointer = bs;
+  *bs_link_pointer = &bs->next;
   bs->breakpoint_at = bl;
   /* If the condition is false, etc., don't do the commands.  */
   bs->commands = NULL;
@@ -4027,10 +4027,10 @@ bpstat_stop_status (struct address_space *aspace,
   struct breakpoint *b = NULL;
   struct bp_location *bl;
   struct bp_location *loc;
-  /* Root of the chain of bpstat's */
-  struct bpstats root_bs[1];
+  /* First item of allocated bpstat's.  */
+  bpstat bs_head = NULL, *bs_link = &bs_head;
   /* Pointer to the last thing in the chain currently.  */
-  bpstat bs = root_bs;
+  bpstat bs;
   int ix;
   int need_remove_insert;
 
@@ -4061,7 +4061,7 @@ bpstat_stop_status (struct address_space *aspace,
 
 	  /* Come here if it's a watchpoint, or if the break address matches */
 
-	  bs = bpstat_alloc (bl, bs);	/* Alloc a bpstat to explain stop */
+	  bs = bpstat_alloc (bl, &bs_link);	/* Alloc a bpstat to explain stop */
 
 	  /* Assume we stop.  Should we find watchpoint that is not actually
 	     triggered, or if condition of breakpoint is false, we'll reset
@@ -4119,7 +4119,7 @@ bpstat_stop_status (struct address_space *aspace,
       if (breakpoint_address_match (loc->pspace->aspace, loc->address,
 				    aspace, bp_addr))
 	{
-	  bs = bpstat_alloc (loc, bs);
+	  bs = bpstat_alloc (loc, &bs_link);
 	  /* For hits of moribund locations, we should just proceed.  */
 	  bs->stop = 0;
 	  bs->print = 0;
@@ -4127,15 +4127,13 @@ bpstat_stop_status (struct address_space *aspace,
 	}
     }
 
-  bs->next = NULL;		/* Terminate the chain */
-
   /* If we aren't stopping, the value of some hardware watchpoint may
      not have changed, but the intermediate memory locations we are
      watching may have.  Don't bother if we're stopping; this will get
      done later.  */
   need_remove_insert = 0;
-  if (! bpstat_causes_stop (root_bs->next))
-    for (bs = root_bs->next; bs != NULL; bs = bs->next)
+  if (! bpstat_causes_stop (bs_head))
+    for (bs = bs_head; bs != NULL; bs = bs->next)
       if (!bs->stop
 	  && bs->breakpoint_at->owner
 	  && is_hardware_watchpoint (bs->breakpoint_at->owner))
@@ -4150,7 +4148,7 @@ bpstat_stop_status (struct address_space *aspace,
   if (need_remove_insert)
     update_global_location_list (1);
 
-  return root_bs->next;
+  return bs_head;
 }
 
 static void