make serial_ops const

I noticed that the serial_ops vtable is not const, but really it ought
to be.

This patch constifies it, removing the only mutable field in the
process.

Tested by rebuilding on x86-64 Fedora 18, both natively and using the
mingw cross tools.

2013-12-19  Tom Tromey  <tromey@redhat.com>

	* serial.c (serial_ops_p): New typedef.
	(serial_ops_list): Now a VEC.
	(serial_interface_lookup): Return const.  Use VEC_iterate.
	(serial_add_interface): Make parameter const.
	(serial_open): Update.
	(serial_fdopen_ops): Make 'ops' const.
	(serial_pipe): Update.
	* ser-tcp.c (_initialize_ser_tcp): Update.
	* ser-pipe.c (_initialize_ser_pipe): Update.
	* ser-unix.c (_initialize_ser_hardwire): Update.
	* ser-mingw.c (_initialize_ser_windows): Update.
	* ser-go32.c (dos_ops): Now const.  Update.
	* serial.h (struct serial) <ops>: Now const.
	(struct serial_ops) <next>: Remove.
	(serial_add_interface): Make parameter const.

8 files changed, 36 insertions, 24 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 513c593..b11726d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,21 @@
+2013-12-19  Tom Tromey  <tromey@redhat.com>
+
+	* serial.c (serial_ops_p): New typedef.
+	(serial_ops_list): Now a VEC.
+	(serial_interface_lookup): Return const.  Use VEC_iterate.
+	(serial_add_interface): Make parameter const.
+	(serial_open): Update.
+	(serial_fdopen_ops): Make 'ops' const.
+	(serial_pipe): Update.
+	* ser-tcp.c (_initialize_ser_tcp): Update.
+	* ser-pipe.c (_initialize_ser_pipe): Update.
+	* ser-unix.c (_initialize_ser_hardwire): Update.
+	* ser-mingw.c (_initialize_ser_windows): Update.
+	* ser-go32.c (dos_ops): Now const.  Update.
+	* serial.h (struct serial) <ops>: Now const.
+	(struct serial_ops) <next>: Remove.
+	(serial_add_interface): Make parameter const.
+
 2013-12-18  Yufeng Zhang  <yufeng.zhang@arm.com>
 
 	* aarch64-linux-nat.c (aarch64_linux_set_debug_regs): Set
diff --git a/gdb/ser-go32.c b/gdb/ser-go32.c
index 4268e2c..6b87f86 100644
--- a/gdb/ser-go32.c
+++ b/gdb/ser-go32.c
@@ -848,10 +848,9 @@ dos_sendbreak (struct serial *scb)
 }
 
 
-static struct serial_ops dos_ops =
+static const struct serial_ops dos_ops =
 {
   "hardwire",
-  0,
   dos_open,
   dos_close,
   NULL,				/* fdopen, not implemented */
diff --git a/gdb/ser-mingw.c b/gdb/ser-mingw.c
index 0431ea9..eef40ce 100644
--- a/gdb/ser-mingw.c
+++ b/gdb/ser-mingw.c
@@ -1232,7 +1232,6 @@ _initialize_ser_windows (void)
   ops = XMALLOC (struct serial_ops);
   memset (ops, 0, sizeof (struct serial_ops));
   ops->name = "hardwire";
-  ops->next = 0;
   ops->open = ser_windows_open;
   ops->close = ser_windows_close;
 
@@ -1268,7 +1267,6 @@ _initialize_ser_windows (void)
   memset (ops, 0, sizeof (struct serial_ops));
 
   ops->name = "terminal";
-  ops->next = 0;
 
   ops->close = ser_console_close;
   ops->get_tty_state = ser_console_get_tty_state;
@@ -1287,7 +1285,6 @@ _initialize_ser_windows (void)
   ops = XMALLOC (struct serial_ops);
   memset (ops, 0, sizeof (struct serial_ops));
   ops->name = "pipe";
-  ops->next = 0;
   ops->open = pipe_windows_open;
   ops->close = pipe_windows_close;
   ops->fdopen = pipe_windows_fdopen;
@@ -1323,7 +1320,6 @@ _initialize_ser_windows (void)
   ops = XMALLOC (struct serial_ops);
   memset (ops, 0, sizeof (struct serial_ops));
   ops->name = "tcp";
-  ops->next = 0;
   ops->open = net_windows_open;
   ops->close = net_windows_close;
   ops->readchar = ser_base_readchar;
diff --git a/gdb/ser-pipe.c b/gdb/ser-pipe.c
index b4ab672..70bec5e 100644
--- a/gdb/ser-pipe.c
+++ b/gdb/ser-pipe.c
@@ -213,7 +213,6 @@ _initialize_ser_pipe (void)
 
   memset (ops, 0, sizeof (struct serial_ops));
   ops->name = "pipe";
-  ops->next = 0;
   ops->open = pipe_open;
   ops->close = pipe_close;
   ops->readchar = ser_base_readchar;
diff --git a/gdb/ser-tcp.c b/gdb/ser-tcp.c
index d8c1ed6..c5c5600 100644
--- a/gdb/ser-tcp.c
+++ b/gdb/ser-tcp.c
@@ -385,7 +385,6 @@ _initialize_ser_tcp (void)
   ops = XMALLOC (struct serial_ops);
   memset (ops, 0, sizeof (struct serial_ops));
   ops->name = "tcp";
-  ops->next = 0;
   ops->open = net_open;
   ops->close = net_close;
   ops->readchar = ser_base_readchar;
diff --git a/gdb/ser-unix.c b/gdb/ser-unix.c
index 1f1372b..d8e4294 100644
--- a/gdb/ser-unix.c
+++ b/gdb/ser-unix.c
@@ -912,7 +912,6 @@ _initialize_ser_hardwire (void)
 
   memset (ops, 0, sizeof (struct serial_ops));
   ops->name = "hardwire";
-  ops->next = 0;
   ops->open = hardwire_open;
   ops->close = hardwire_close;
   /* FIXME: Don't replace this with the equivalent ser_base*() until
diff --git a/gdb/serial.c b/gdb/serial.c
index 78e9085..0e0c4f7 100644
--- a/gdb/serial.c
+++ b/gdb/serial.c
@@ -30,9 +30,12 @@ extern void _initialize_serial (void);
 
 static unsigned int global_serial_debug_p;
 
-/* Linked list of serial I/O handlers.  */
+typedef const struct serial_ops *serial_ops_p;
+DEF_VEC_P (serial_ops_p);
 
-static struct serial_ops *serial_ops_list = NULL;
+/* Serial I/O handlers.  */
+
+VEC (serial_ops_p) *serial_ops_list = NULL;
 
 /* Pointer to list of scb's.  */
 
@@ -44,7 +47,7 @@ static struct serial *scb_base;
 static char *serial_logfile = NULL;
 static struct ui_file *serial_logfp = NULL;
 
-static struct serial_ops *serial_interface_lookup (const char *);
+static const struct serial_ops *serial_interface_lookup (const char *);
 static void serial_logchar (struct ui_file *stream,
 			    int ch_type, int ch, int timeout);
 static const char logbase_hex[] = "hex";
@@ -143,12 +146,13 @@ serial_log_command (const char *cmd)
 }
 
 
-static struct serial_ops *
+static const struct serial_ops *
 serial_interface_lookup (const char *name)
 {
-  struct serial_ops *ops;
+  const struct serial_ops *ops;
+  int i;
 
-  for (ops = serial_ops_list; ops; ops = ops->next)
+  for (i = 0; VEC_iterate (serial_ops_p, serial_ops_list, i, ops); ++i)
     if (strcmp (name, ops->name) == 0)
       return ops;
 
@@ -156,10 +160,9 @@ serial_interface_lookup (const char *name)
 }
 
 void
-serial_add_interface (struct serial_ops *optable)
+serial_add_interface (const struct serial_ops *optable)
 {
-  optable->next = serial_ops_list;
-  serial_ops_list = optable;
+  VEC_safe_push (serial_ops_p, serial_ops_list, optable);
 }
 
 /* Return the open serial device for FD, if found, or NULL if FD is
@@ -183,7 +186,7 @@ struct serial *
 serial_open (const char *name)
 {
   struct serial *scb;
-  struct serial_ops *ops;
+  const struct serial_ops *ops;
   const char *open_name = name;
 
   if (strcmp (name, "pc") == 0)
@@ -246,7 +249,7 @@ serial_open (const char *name)
    interface ops OPS.  */
 
 static struct serial *
-serial_fdopen_ops (const int fd, struct serial_ops *ops)
+serial_fdopen_ops (const int fd, const struct serial_ops *ops)
 {
   struct serial *scb;
 
@@ -584,7 +587,7 @@ serial_done_wait_handle (struct serial *scb)
 int
 serial_pipe (struct serial *scbs[2])
 {
-  struct serial_ops *ops;
+  const struct serial_ops *ops;
   int fildes[2];
 
   ops = serial_interface_lookup ("pipe");
diff --git a/gdb/serial.h b/gdb/serial.h
index 7a97e28..86c3960 100644
--- a/gdb/serial.h
+++ b/gdb/serial.h
@@ -228,7 +228,7 @@ struct serial
        If != -1, this descriptor should be non-blocking or
        ops->avail should be non-NULL.  */
     int error_fd;               
-    struct serial_ops *ops;	/* Function vector */
+    const struct serial_ops *ops; /* Function vector */
     void *state;       		/* Local context info for open FD */
     serial_ttystate ttystate;	/* Not used (yet) */
     int bufcnt;			/* Amount of data remaining in receive
@@ -251,7 +251,6 @@ struct serial
 struct serial_ops
   {
     char *name;
-    struct serial_ops *next;
     int (*open) (struct serial *, const char *name);
     void (*close) (struct serial *);
     int (*fdopen) (struct serial *, int fd);
@@ -301,7 +300,7 @@ struct serial_ops
 
 /* Add a new serial interface to the interface list.  */
 
-extern void serial_add_interface (struct serial_ops * optable);
+extern void serial_add_interface (const struct serial_ops * optable);
 
 /* File in which to record the remote debugging session.  */