2011-11-02 Stan Shebs <stan@codesourcery.com>

String collection for tracepoints.
	* NEWS: Mention string collection.
	* common/ax.def (tracenz): New bytecode.
	* ax-gdb.h (trace_string_kludge): Declare.
	* ax-gdb.c: Include valprint.h and c-lang.h.
	(trace_string_kludge): New global.
	(gen_traced_pop): Add string case.
	(agent_command): Add string case.
	* tracepoint.h (decode_agent_options): Declare.
	* tracepoint.c: Include cli-utils.h.
	(decode_agent_options): New function.
	(validate_actionline): Call it.
	(encode_actions_1): Ditto.
	* target.h (struct target_ops): New method to_supports_string_tracing.
	(target_supports_string_tracing): New macro.
	* target.c (update_current_target): Add to_supports_string_tracing.
	* remote.c (struct remote_state): New field string_tracing.
	(remote_string_tracing_feature): New function.
	(remote_protocol_features): New feature tracenz.
	(remote_supports_string_tracing): New function.
	(init_remote_ops): Set to_supports_string_tracing.

	* tracepoint.c (agent_mem_read_string): New function.
	(eval_agent_expr): Call it for tracenz.
	* server.c (handle_query): Report support for tracenz.

	* gdb.texinfo (Tracepoint Action Lists): Document collect/s.
	(General Query Packets): Describe tracenz feature.
	* agentexpr.texi (Bytecode Descriptions): Describe tracenz.

	* gdb.trace/collection.c: Add code using strings.
	* gdb.trace/collection.exp: Add tests of string collection.

gdb/tracepoint.c

@@ -52,6 +52,7 @@
 #include "ax-gdb.h"
 #include "memrange.h"
 #include "exceptions.h"
+#include "cli/cli-utils.h"
 
 /* readline include files */
 #include "readline/readline.h"
@@ -574,6 +575,46 @@ teval_pseudocommand (char *args, int from_tty)
   error (_("This command can only be used in a tracepoint actions list."));
 }
 
+/* Parse any collection options, such as /s for strings.  */
+
+char *
+decode_agent_options (char *exp)
+{
+  struct value_print_options opts;
+
+  if (*exp != '/')
+    return exp;
+
+  /* Call this to borrow the print elements default for collection
+     size.  */
+  get_user_print_options (&opts);
+
+  exp++;
+  if (*exp == 's')
+    {
+      if (target_supports_string_tracing ())
+	{
+	  /* Allow an optional decimal number giving an explicit maximum
+	     string length, defaulting it to the "print elements" value;
+	     so "collect/s80 mystr" gets at most 80 bytes of string.  */
+	  trace_string_kludge = opts.print_max;
+	  exp++;
+	  if (*exp >= '0' && *exp <= '9')
+	    trace_string_kludge = atoi (exp);
+	  while (*exp >= '0' && *exp <= '9')
+	    exp++;
+	}
+      else
+	error (_("Target does not support \"/s\" option for string tracing."));
+    }
+  else
+    error (_("Undefined collection format \"%c\"."), *exp);
+
+  exp = skip_spaces (exp);
+
+  return exp;
+}
+
 /* Enter a list of actions for a tracepoint.  */
 static void
 trace_actions_command (char *args, int from_tty)
@@ -656,6 +697,10 @@ validate_actionline (char **line, struct breakpoint *b)
 
   if (cmd_cfunc_eq (c, collect_pseudocommand))
     {
+      trace_string_kludge = 0;
+      if (*p == '/')
+	p = decode_agent_options (p);
+
       do
 	{			/* Repeat over a comma-separated list.  */
 	  QUIT;			/* Allow user to bail out with ^C.  */
@@ -1313,6 +1358,10 @@ encode_actions_1 (struct command_line *action,
 
       if (cmd_cfunc_eq (cmd, collect_pseudocommand))
 	{
+	  trace_string_kludge = 0;
+	  if (*action_exp == '/')
+	    action_exp = decode_agent_options (action_exp);
+
 	  do
 	    {			/* Repeat over a comma-separated list.  */
 	      QUIT;		/* Allow user to bail out with ^C.  */
@@ -2581,6 +2630,9 @@ trace_dump_actions (struct command_line *action,
 	     STEPPING_ACTIONS should be equal.  */
 	  if (stepping_frame == stepping_actions)
 	    {
+	      if (*action_exp == '/')
+		action_exp = decode_agent_options (action_exp);
+
 	      do
 		{		/* Repeat over a comma-separated list.  */
 		  QUIT;		/* Allow user to bail out with ^C.  */