Re: [rfa] hardware breakpoints -- remote targets

[Grace Sainsbury <graces@redhat.com>]

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I revised the patch to include Mark Salter's earlier patch, as well as
his documentation changes.

ok to commit?

grace

Changelog:

2002-08-08  Grace Sainsbury  <graces@redhat.com>
	
	* remote.c: (remote_wait, remote_async_wait): Add check for awatch
	T-packets; the 'a' is not taken as a register number.
	(set_hardware_watchpoint_limit, show_hardware_watchpoint_limit)
	(set_hardware_breakpoint_limit, show_hardware_breakpoint_limit):
	New functions. Add commands to call them.
	(remote_check_watch_resources, remote_stopped_by_watchpoint)
	(remote_stopped_data_address): New functions; add to target
	vector.
	(remote_insert_hw_breakpoint, remote_remove_hw_breakpoint): Change
	prototypes to match other implementations of this
	function. replace integer argument with pointer -- the length
	field in the Z-packet is the length of what is pointed to or 1 if
	pointer is null. Add to target vector.
	(remote_insert_watchpoint, remote_remove_watchpoint): Add to
	target vector.

	From Mark Salter:
	* remote.c (remote_wait): Add support to extract optional
	watchpoint information from T-packet. Ignore unrecognized
	optional info in T-packet.
	(remote_async_wait): Ditto.

doc/Changelog: 

2002-08-08  Grace Sainsbury  <graces@redhat.com>

	From Mark Salter:            
	* gdb.texinfo (Protocol): Document T packet extension to
	allow watchpoint address reporting.

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Index: remote.c
===================================================================
RCS file: /cvs/src/src/gdb/remote.c,v
retrieving revision 1.89
diff -u -r1.89 remote.c
--- remote.c	23 Jul 2002 18:55:06 -0000	1.89
+++ remote.c	8 Aug 2002 17:02:27 -0000
@@ -250,6 +250,7 @@
   long remote_packet_size;
 };
 
+
 /* Handle for retreving the remote protocol data from gdbarch.  */
 static struct gdbarch_data *remote_gdbarch_data_handle;
 
@@ -342,6 +343,14 @@
 
 /* */
 
+/* This is set to the data address of the access causing the target
+ * to stop for a watchpoint. */
+static CORE_ADDR remote_watch_data_address;
+
+/* This is non-zero if taregt stopped for a watchpoint. */
+static int remote_stopped_by_watchpoint_p;
+
+
 static struct target_ops remote_ops;
 
 static struct target_ops extended_remote_ops;
@@ -1107,7 +1116,7 @@
 
 #define BUF_THREAD_ID_SIZE (OPAQUETHREADBYTES*2)
 
-char *unpack_varlen_hex (char *buff, int *result);
+char *unpack_varlen_hex (char *buff, ULONGEST *result);
 
 static char *unpack_nibble (char *buf, int *val);
 
@@ -1228,7 +1237,7 @@
 
 char *
 unpack_varlen_hex (char *buff,	/* packet to parse */
-		   int *result)
+		   ULONGEST *result)
 {
   int nibble;
   int retval = 0;
@@ -3007,7 +3016,8 @@
 {
   struct remote_state *rs = get_remote_state ();
   unsigned char *buf = alloca (rs->remote_packet_size);
-  int thread_num = -1;
+  ULONGEST thread_num = -1;
+  ULONGEST addr;
 
   status->kind = TARGET_WAITKIND_EXITED;
   status->value.integer = 0;
@@ -3025,6 +3035,8 @@
       if (target_wait_loop_hook)
 	(*target_wait_loop_hook) ();
 
+      remote_stopped_by_watchpoint_p = 0;
+
       switch (buf[0])
 	{
 	case 'E':		/* Error of some sort */
@@ -3048,10 +3060,19 @@
 		unsigned char *p1;
 		char *p_temp;
 		int fieldsize;
+		LONGEST pnum = 0;
 
-		/* Read the ``P'' register number.  */
-		LONGEST pnum = strtol ((const char *) p, &p_temp, 16);
-		p1 = (unsigned char *) p_temp;
+		/* If this packet is an awatch packet, don't parse the 'a'
+		   as a register number.  */
+
+		if (!strstr ((const char *) p, "awatch"))
+		  {
+		    /* Read the ``P'' register number.  */
+		    pnum = strtol ((const char *) p, &p_temp, 16);
+		    p1 = (unsigned char *) p_temp;
+		  }
+		else 
+		  p1=p;
 
 		if (p1 == p)	/* No register number present here */
 		  {
@@ -3066,6 +3087,21 @@
 			record_currthread (thread_num);
 			p = (unsigned char *) p_temp;
 		      }
+		    else if ((strncmp ((const char *) p, "watch", p1 - p) == 0)
+			     || (strncmp ((const char *) p, "rwatch", p1 - p) == 0)
+			     || (strncmp ((const char *) p, "awatch", p1 - p) == 0))
+		      {
+			remote_stopped_by_watchpoint_p = 1;
+			p = unpack_varlen_hex (++p1, &addr);
+			remote_watch_data_address = (CORE_ADDR)addr;
+		      }
+		    else
+ 		      {
+ 			/* silently skip unknown optional info */
+ 			p_temp = (unsigned char *) strchr ((const char *) p1+1, ';');
+ 			if (p_temp)
+			  p = p_temp;
+ 		      }
 		  }
 		else
 		  {
@@ -3221,11 +3257,14 @@
 {
   struct remote_state *rs = get_remote_state ();
   unsigned char *buf = alloca (rs->remote_packet_size);
-  int thread_num = -1;
+  ULONGEST thread_num = -1;
+  ULONGEST addr;
 
   status->kind = TARGET_WAITKIND_EXITED;
   status->value.integer = 0;
 
+  remote_stopped_by_watchpoint_p = 0;
+
   while (1)
     {
       unsigned char *p;
@@ -3268,10 +3307,19 @@
 		unsigned char *p1;
 		char *p_temp;
 		int fieldsize;
+		long pnum = 0;
 
-		/* Read the register number */
-		long pnum = strtol ((const char *) p, &p_temp, 16);
-		p1 = (unsigned char *) p_temp;
+		/* If this packet is an awatch packet, don't parse the 'a'
+		   as a register number.  */
+		
+		if (!strstr ((const char *) p, "awatch"))
+		  {
+		    /* Read the register number.  */
+		    pnum = strtol ((const char *) p, &p_temp, 16);
+		    p1 = (unsigned char *) p_temp;
+		  }
+		else 
+		  p1=p;
 
 		if (p1 == p)	/* No register number present here */
 		  {
@@ -3286,7 +3334,23 @@
 			record_currthread (thread_num);
 			p = (unsigned char *) p_temp;
 		      }
+		    else if ((strncmp ((const char *) p, "watch", p1 - p) == 0)
+			     || (strncmp ((const char *) p, "rwatch", p1 - p) == 0)
+			     || (strncmp ((const char *) p, "awatch", p1 - p) == 0))
+		      {
+			remote_stopped_by_watchpoint_p = 1;
+			p = unpack_varlen_hex (++p1, &addr);
+			remote_watch_data_address = (CORE_ADDR)addr;
+		      }
+		    else
+ 		      {
+ 			/* silently skip unknown optional info */
+ 			p_temp = (unsigned char *) strchr ((const char *) p1+1, ';');
+ 			if (p_temp)
+			  p = p_temp;
+ 		      }
 		  }
+		
 		else
 		  {
 		    struct packet_reg *reg = packet_reg_from_pnum (rs, pnum);
@@ -4797,7 +4861,7 @@
 /* FIXME: This function should be static and a member of the remote
    target vector. */
 
-int
+static int
 remote_insert_watchpoint (CORE_ADDR addr, int len, int type)
 {
   struct remote_state *rs = get_remote_state ();
@@ -4834,7 +4898,7 @@
 /* FIXME: This function should be static and a member of the remote
    target vector. */
 
-int
+static int
 remote_remove_watchpoint (CORE_ADDR addr, int len, int type)
 {
   struct remote_state *rs = get_remote_state ();
@@ -4867,16 +4931,109 @@
 		  "remote_remove_watchpoint: reached end of function");
 }
 
-/* FIXME: This function should be static and a member of the remote
-   target vector. */
+
+int remote_hw_watchpoint_limit = 0;
+int remote_hw_breakpoint_limit = 0;
+
+
+static void
+set_hardware_watchpoint_limit (char *args, int from_tty)
+{
+  if (args)
+    {
+      char *arg_end;
+      int val = strtoul (args, &arg_end, 10);
+      if (*args && *arg_end == '\0')
+        {
+          remote_hw_watchpoint_limit = val;
+	  return;
+	}
+    }
+  error ("Illegal argument for \"set remote hardware-watchpoint-limit\" command");
+}
+
+static void
+show_hardware_watchpoint_limit (char *args, int from_tty)
+{
+  if (args)
+    error ("Garbage after \"show remote hardware-watchpoint-limit\" command: `%s'", args);
+  printf_unfiltered ("Remote target supports %d hardware watchpoints.\n",
+		     remote_hw_watchpoint_limit);
+}
+
+static void
+set_hardware_breakpoint_limit (char *args, int from_tty)
+{
+  if (args)
+    {
+      char *arg_end;
+      int val = strtoul (args, &arg_end, 10);
+      if (*args && *arg_end == '\0')
+        {
+          remote_hw_breakpoint_limit = val;
+	  return;
+	}
+    }
+  error ("Illegal argument for \"set remote hardware-breakpoint-limit\" command");
+}
+
+static void
+show_hardware_breakpoint_limit (char *args, int from_tty)
+{
+  if (args)
+    error ("Garbage after \"show remote hardware-breakpoint-limit\" command: `%s'", args);
+  printf_unfiltered ("Remote target supports %d hardware breakpoints.\n",
+		     remote_hw_breakpoint_limit);
+}
+
 
 int
-remote_insert_hw_breakpoint (CORE_ADDR addr, int len)
+remote_check_watch_resources (int type, int cnt, int ot)
 {
+  if (type == bp_hardware_breakpoint)
+    {
+      if (remote_hw_breakpoint_limit == 0)
+	return 0;
+      else if (cnt <= remote_hw_breakpoint_limit)
+	return 1;
+    }
+  else
+    {
+      if (remote_hw_watchpoint_limit == 0)
+	return 0;
+      else if (ot)
+	return -1;
+      else if (cnt <= remote_hw_watchpoint_limit)
+	return 1;
+    }
+  return -1;
+}
+
+int
+remote_stopped_by_watchpoint (void)
+{
+    return remote_stopped_by_watchpoint_p;
+}
+
+CORE_ADDR
+remote_stopped_data_address (void)
+{
+  if (remote_stopped_by_watchpoint ())
+    return remote_watch_data_address;
+  return (CORE_ADDR)0;
+}
+
+
+static int
+remote_insert_hw_breakpoint (CORE_ADDR addr, char *shadow)
+{
+  int len=0;
   struct remote_state *rs = get_remote_state ();
   char *buf = alloca (rs->remote_packet_size);
   char *p = buf;
       
+  len = strlen (shadow);
+  len = len ? len : 1;
   if (remote_protocol_Z[Z_PACKET_HARDWARE_BP].support == PACKET_DISABLE)
     error ("Can't set hardware breakpoint without the '%s' (%s) packet\n",
 	   remote_protocol_Z[Z_PACKET_HARDWARE_BP].name,
@@ -4902,19 +5059,19 @@
       return 0;
     }
   internal_error (__FILE__, __LINE__,
-		  "remote_remove_watchpoint: reached end of function");
+		  "remote_insert_hw_breakpoint: reached end of function");
 }
 
-/* FIXME: This function should be static and a member of the remote
-   target vector. */
 
-int 
-remote_remove_hw_breakpoint (CORE_ADDR addr, int len)
+static int 
+remote_remove_hw_breakpoint (CORE_ADDR addr, char * shadow)
 {
+  int len;
   struct remote_state *rs = get_remote_state ();
   char *buf = alloca (rs->remote_packet_size);
   char *p = buf;
   
+  len = sizeof (shadow);
   if (remote_protocol_Z[Z_PACKET_HARDWARE_BP].support == PACKET_DISABLE)
     error ("Can't clear hardware breakpoint without the '%s' (%s) packet\n",
 	   remote_protocol_Z[Z_PACKET_HARDWARE_BP].name,
@@ -4940,7 +5097,7 @@
       return 0;
     }
   internal_error (__FILE__, __LINE__,
-		  "remote_remove_watchpoint: reached end of function");
+		  "remote_remove_hw_breakpoint: reached end of function");
 }
 
 /* Some targets are only capable of doing downloads, and afterwards
@@ -5417,6 +5574,13 @@
   remote_ops.to_files_info = remote_files_info;
   remote_ops.to_insert_breakpoint = remote_insert_breakpoint;
   remote_ops.to_remove_breakpoint = remote_remove_breakpoint;
+  remote_ops.to_stopped_by_watchpoint = remote_stopped_by_watchpoint;
+  remote_ops.to_stopped_data_address = remote_stopped_data_address;
+  remote_ops.to_can_use_hw_breakpoint = remote_check_watch_resources;
+  remote_ops.to_insert_hw_breakpoint = remote_insert_hw_breakpoint;
+  remote_ops.to_remove_hw_breakpoint = remote_remove_hw_breakpoint;
+  remote_ops.to_insert_watchpoint = remote_insert_watchpoint;
+  remote_ops.to_remove_watchpoint = remote_remove_watchpoint;
   remote_ops.to_kill = remote_kill;
   remote_ops.to_load = generic_load;
   remote_ops.to_mourn_inferior = remote_mourn;
@@ -5832,7 +5996,14 @@
   remote_cisco_ops.to_xfer_memory = remote_xfer_memory;
   remote_cisco_ops.to_files_info = remote_files_info;
   remote_cisco_ops.to_insert_breakpoint = remote_insert_breakpoint;
-  remote_cisco_ops.to_remove_breakpoint = remote_remove_breakpoint;
+  remote_cisco_ops.to_remove_breakpoint = remote_remove_breakpoint;  
+  remote_cisco_ops.to_remove_hw_breakpoint = remote_remove_hw_breakpoint;
+  remote_cisco_ops.to_insert_hw_breakpoint = remote_insert_hw_breakpoint;
+  remote_cisco_ops.to_insert_watchpoint = remote_insert_watchpoint;
+  remote_cisco_ops.to_remove_watchpoint = remote_remove_watchpoint;
+  remote_cisco_ops.to_stopped_by_watchpoint = remote_stopped_by_watchpoint;
+  remote_cisco_ops.to_stopped_data_address = remote_stopped_data_address;
+  remote_cisco_ops.to_can_use_hw_breakpoint = remote_check_watch_resources;
   remote_cisco_ops.to_kill = remote_kill;
   remote_cisco_ops.to_load = generic_load;
   remote_cisco_ops.to_mourn_inferior = remote_cisco_mourn;
@@ -5922,6 +6093,13 @@
   remote_async_ops.to_files_info = remote_files_info;
   remote_async_ops.to_insert_breakpoint = remote_insert_breakpoint;
   remote_async_ops.to_remove_breakpoint = remote_remove_breakpoint;
+  remote_async_ops.to_can_use_hw_breakpoint = remote_check_watch_resources;
+  remote_async_ops.to_insert_hw_breakpoint = remote_insert_hw_breakpoint;
+  remote_async_ops.to_remove_hw_breakpoint = remote_remove_hw_breakpoint;
+  remote_async_ops.to_insert_watchpoint = remote_insert_watchpoint;
+  remote_async_ops.to_remove_watchpoint = remote_remove_watchpoint;
+  remote_async_ops.to_stopped_by_watchpoint = remote_stopped_by_watchpoint;
+  remote_async_ops.to_stopped_data_address = remote_stopped_data_address;
   remote_async_ops.to_terminal_inferior = remote_async_terminal_inferior;
   remote_async_ops.to_terminal_ours = remote_async_terminal_ours;
   remote_async_ops.to_kill = remote_async_kill;
@@ -6114,6 +6292,22 @@
   add_cmd ("memory-read-packet-size", no_class,
 	   show_memory_read_packet_size,
 	   "Show the maximum number of bytes per memory-read packet.\n",
+	   &remote_show_cmdlist);
+  add_cmd ("hardware-watchpoint-limit", no_class,
+	   set_hardware_watchpoint_limit,
+	   "Set the maximum number of target hardware watchpoints.\n",
+	   &remote_set_cmdlist);
+  add_cmd ("hardware-watchpoint-limit", no_class,
+	   show_hardware_watchpoint_limit,
+	   "Show the maximum number of target hardware watchpoints.\n",
+	   &remote_show_cmdlist);
+  add_cmd ("hardware-breakpoint-limit", no_class,
+	   set_hardware_breakpoint_limit,
+	   "Set the maximum number of target hardware breakpoints.\n",
+	   &remote_set_cmdlist);
+  add_cmd ("hardware-breakpoint-limit", no_class,
+	   show_hardware_breakpoint_limit,
+	   "Show the maximum number of target hardware breakpoints.\n",
 	   &remote_show_cmdlist);
 
   add_show_from_set
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.107
diff -u -r1.107 gdb.texinfo
--- doc/gdb.texinfo	3 Aug 2002 23:37:07 -0000	1.107
+++ doc/gdb.texinfo	8 Aug 2002 17:02:33 -0000
@@ -14751,10 +14751,11 @@
 @var{AA} = two hex digit signal number; @var{n...} = register number
 (hex), @var{r...}  = target byte ordered register contents, size defined
 by @code{REGISTER_RAW_SIZE}; @var{n...} = @samp{thread}, @var{r...} =
-thread process ID, this is a hex integer; @var{n...} = other string not
-starting with valid hex digit.  @value{GDBN} should ignore this
-@var{n...}, @var{r...} pair and go on to the next.  This way we can
-extend the protocol.
+thread process ID, this is a hex integer; @var{n...} = (@samp{watch} | 
+@samp{rwatch} | @samp{awatch}, @var{r...} = data address, this is a hex
+integer; @var{n...} = other string not starting with valid hex digit.
+@value{GDBN} should ignore this @var{n...}, @var{r...} pair and go on
+to the next.  This way we can extend the protocol.
 
 @item @code{W}@var{AA}
 @tab