Make bp_location usage const

[Vladimir Prus <vladimir at codesourcery dot com>]

Many parts of breakpoint.c make only read-only use
of breakpoint location list. However, it's somewhat
hard to gather from the code. This patch adds 'const'
qualifiers in a number of places to make this really
obvious. OK?

- Volodya

commit 27e15cd23711a14c73736baf532b7129098b32b0
Author: Vladimir Prus <vladimir@codesourcery.com>
Date:   Wed Nov 14 20:07:38 2007 +0300

    Apply const qualifier to some users of bp_location.
    
    	* breakpoint.h (struct bpstats): Make
    	the breakpoint_at field point at const bp_location.
    	* breakpoint.c (bpstat_alloc): Accept const
    	bp_location.
    	(breakpoint_here_p, breakpoint_inserted_here_p)
    	(software_breakpoint_inserted_here_p)
    	(breakpoint_thread_match, bpstat_stop_status): Use
    	const bp_location for iteration.
    	(print_it_typical, print_bp_stop_message): Use
    	const bp_location variable.

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index b67851d..d067405 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -109,7 +109,7 @@ static void breakpoints_info (char *, int);
 
 static void breakpoint_1 (int, int);
 
-static bpstat bpstat_alloc (struct bp_location *, bpstat);
+static bpstat bpstat_alloc (const struct bp_location *, bpstat);
 
 static int breakpoint_cond_eval (void *);
 
@@ -1733,7 +1733,7 @@ breakpoint_init_inferior (enum inf_context context)
 enum breakpoint_here
 breakpoint_here_p (CORE_ADDR pc)
 {
-  struct bp_location *bpt;
+  const struct bp_location *bpt;
   int any_breakpoint_here = 0;
 
   ALL_BP_LOCATIONS (bpt)
@@ -1768,7 +1768,7 @@ breakpoint_here_p (CORE_ADDR pc)
 int
 breakpoint_inserted_here_p (CORE_ADDR pc)
 {
-  struct bp_location *bpt;
+  const struct bp_location *bpt;
 
   ALL_BP_LOCATIONS (bpt)
     {
@@ -1801,7 +1801,7 @@ breakpoint_inserted_here_p (CORE_ADDR pc)
 int
 software_breakpoint_inserted_here_p (CORE_ADDR pc)
 {
-  struct bp_location *bpt;
+  const struct bp_location *bpt;
   int any_breakpoint_here = 0;
 
   ALL_BP_LOCATIONS (bpt)
@@ -1834,7 +1834,7 @@ software_breakpoint_inserted_here_p (CORE_ADDR pc)
 int
 breakpoint_thread_match (CORE_ADDR pc, ptid_t ptid)
 {
-  struct bp_location *bpt;
+  const struct bp_location *bpt;
   int thread;
 
   thread = pid_to_thread_id (ptid);
@@ -2159,7 +2159,7 @@ print_it_typical (bpstat bs)
 {
   struct cleanup *old_chain, *ui_out_chain;
   struct breakpoint *b;
-  struct bp_location *bl;
+  const struct bp_location *bl;
   struct ui_stream *stb;
   stb = ui_out_stream_new (uiout);
   old_chain = make_cleanup_ui_out_stream_delete (stb);
@@ -2440,7 +2440,7 @@ print_bp_stop_message (bpstat bs)
 
     case print_it_normal:
       {
-	struct bp_location *bl = bs->breakpoint_at;
+	const struct bp_location *bl = bs->breakpoint_at;
 	struct breakpoint *b = bl ? bl->owner : NULL;
 	
 	/* Normal case.  Call the breakpoint's print_it method, or
@@ -2520,7 +2520,7 @@ breakpoint_cond_eval (void *exp)
 /* Allocate a new bpstat and chain it to the current one.  */
 
 static bpstat
-bpstat_alloc (struct bp_location *bl, bpstat cbs /* Current "bs" value */ )
+bpstat_alloc (const struct bp_location *bl, bpstat cbs /* Current "bs" value */ )
 {
   bpstat bs;
 
@@ -2749,7 +2749,7 @@ bpstat
 bpstat_stop_status (CORE_ADDR bp_addr, ptid_t ptid)
 {
   struct breakpoint *b = NULL;
-  struct bp_location *bl;
+  const struct bp_location *bl;
   /* True if we've hit a breakpoint (as opposed to a watchpoint).  */
   int real_breakpoint = 0;
   /* Root of the chain of bpstat's */
diff --git a/gdb/breakpoint.h b/gdb/breakpoint.h
index 7919d3f..f13d41b 100644
--- a/gdb/breakpoint.h
+++ b/gdb/breakpoint.h
@@ -642,7 +642,7 @@ struct bpstats
        place, and a bpstat reflects the fact that both have been hit.  */
     bpstat next;
     /* Breakpoint that we are at.  */
-    struct bp_location *breakpoint_at;
+    const struct bp_location *breakpoint_at;
     /* Commands left to be done.  */
     struct command_line *commands;
     /* Old value associated with a watchpoint.  */