Index: ax-gdb.c
===================================================================
RCS file: /cvs/src/src/gdb/ax-gdb.c,v
retrieving revision 1.89
diff -p -r1.89 ax-gdb.c
*** ax-gdb.c	27 Sep 2011 13:09:34 -0000	1.89
--- ax-gdb.c	3 Oct 2011 15:34:16 -0000
***************
*** 42,47 ****
--- 42,50 ----
  #include "cp-support.h"
  #include "arch-utils.h"
  
+ #include "valprint.h"
+ #include "c-lang.h"
+ 
  /* To make sense of this file, you should read doc/agentexpr.texi.
     Then look at the types and enums in ax-gdb.h.  For the code itself,
     look at gen_expr, towards the bottom; that's the main function that
*************** maybe_const_expr (union exp_element **pc
*** 335,340 ****
--- 338,348 ----
     emits the trace bytecodes at the appropriate points.  */
  int trace_kludge;
  
+ /* Inspired by trace_kludge, this indicates that pointers to chars
+    should get an added tracenz bytecode to record nonzero bytes, up to
+    a length that is the value of string_kludge.  */
+ int string_kludge;
+ 
  /* Scan for all static fields in the given class, including any base
     classes, and generate tracing bytecodes for each.  */
  
*************** static void
*** 393,411 ****
  gen_traced_pop (struct gdbarch *gdbarch,
  		struct agent_expr *ax, struct axs_value *value)
  {
    if (trace_kludge)
      switch (value->kind)
        {
        case axs_rvalue:
! 	/* We don't trace rvalues, just the lvalues necessary to
! 	   produce them.  So just dispose of this value.  */
! 	ax_simple (ax, aop_pop);
  	break;
  
        case axs_lvalue_memory:
  	{
  	  int length = TYPE_LENGTH (check_typedef (value->type));
  
  	  /* There's no point in trying to use a trace_quick bytecode
  	     here, since "trace_quick SIZE pop" is three bytes, whereas
  	     "const8 SIZE trace" is also three bytes, does the same
--- 401,435 ----
  gen_traced_pop (struct gdbarch *gdbarch,
  		struct agent_expr *ax, struct axs_value *value)
  {
+   int string_trace = 0;
+   if (string_kludge
+       && TYPE_CODE (value->type) == TYPE_CODE_PTR
+       && c_textual_element_type (check_typedef (TYPE_TARGET_TYPE (value->type)),
+ 				 's'))
+     string_trace = 1;
+ 
    if (trace_kludge)
      switch (value->kind)
        {
        case axs_rvalue:
! 	if (string_trace)
! 	  {
! 	    ax_const_l (ax, string_kludge);
! 	    ax_simple (ax, aop_tracenz);
! 	  }
! 	else
! 	  /* We don't trace rvalues, just the lvalues necessary to
! 	     produce them.  So just dispose of this value.  */
! 	  ax_simple (ax, aop_pop);
  	break;
  
        case axs_lvalue_memory:
  	{
  	  int length = TYPE_LENGTH (check_typedef (value->type));
  
+ 	  if (string_trace)
+ 	    ax_simple (ax, aop_dup);
+ 
  	  /* There's no point in trying to use a trace_quick bytecode
  	     here, since "trace_quick SIZE pop" is three bytes, whereas
  	     "const8 SIZE trace" is also three bytes, does the same
*************** gen_traced_pop (struct gdbarch *gdbarch,
*** 413,418 ****
--- 437,449 ----
  	     work correctly for objects with large sizes.  */
  	  ax_const_l (ax, length);
  	  ax_simple (ax, aop_trace);
+ 
+ 	  if (string_trace)
+ 	    {
+ 	      ax_simple (ax, aop_ref32);
+ 	      ax_const_l (ax, string_kludge);
+ 	      ax_simple (ax, aop_tracenz);
+ 	    }
  	}
  	break;
  
*************** gen_traced_pop (struct gdbarch *gdbarch,
*** 422,427 ****
--- 453,467 ----
  	   larger than will fit in a stack, so just mark it for
  	   collection and be done with it.  */
  	ax_reg_mask (ax, value->u.reg);
+        
+ 	/* But if the register points to a string, assume the value
+ 	   will fit on the stack and push it anyway.  */
+ 	if (string_trace)
+ 	  {
+ 	    ax_reg (ax, value->u.reg);
+ 	    ax_const_l (ax, string_kludge);
+ 	    ax_simple (ax, aop_tracenz);
+ 	  }
  	break;
        }
    else
*************** agent_command (char *exp, int from_tty)
*** 2489,2494 ****
--- 2529,2538 ----
    if (exp == 0)
      error_no_arg (_("expression to translate"));
  
+   string_kludge = 0;
+   if (*exp == '/')
+     exp = decode_agent_options (exp);
+ 
    /* Recognize the return address collection directive specially.  Note
       that it is not really an expression of any sort.  */
    if (strcmp (exp, "$_ret") == 0)
Index: ax-gdb.h
===================================================================
RCS file: /cvs/src/src/gdb/ax-gdb.h,v
retrieving revision 1.21
diff -p -r1.21 ax-gdb.h
*** ax-gdb.h	27 Sep 2011 13:09:35 -0000	1.21
--- ax-gdb.h	3 Oct 2011 15:34:16 -0000
*************** extern struct agent_expr *gen_trace_for_
*** 112,116 ****
--- 112,117 ----
  extern struct agent_expr *gen_eval_for_expr (CORE_ADDR, struct expression *);
  
  extern int trace_kludge;
+ extern int string_kludge;
  
  #endif /* AX_GDB_H */
Index: remote.c
===================================================================
RCS file: /cvs/src/src/gdb/remote.c,v
retrieving revision 1.463
diff -p -r1.463 remote.c
*** remote.c	14 Sep 2011 12:26:29 -0000	1.463
--- remote.c	3 Oct 2011 15:34:16 -0000
*************** struct remote_state
*** 331,336 ****
--- 331,339 ----
       tracepoints while a trace experiment is running.  */
    int enable_disable_tracepoints;
  
+   /* True if the stub can collect strings using tracenz bytecode.  */
+   int string_tracing;
+ 
    /* Nonzero if the user has pressed Ctrl-C, but the target hasn't
       responded to that.  */
    int ctrlc_pending_p;
*************** remote_enable_disable_tracepoint_feature
*** 3711,3716 ****
--- 3714,3729 ----
    rs->enable_disable_tracepoints = (support == PACKET_ENABLE);
  }
  
+ static void
+ remote_string_tracing_feature (const struct protocol_feature *feature,
+ 			       enum packet_support support,
+ 			       const char *value)
+ {
+   struct remote_state *rs = get_remote_state ();
+ 
+   rs->string_tracing = (support == PACKET_ENABLE);
+ }
+ 
  static struct protocol_feature remote_protocol_features[] = {
    { "PacketSize", PACKET_DISABLE, remote_packet_size, -1 },
    { "qXfer:auxv:read", PACKET_DISABLE, remote_supported_packet,
*************** static struct protocol_feature remote_pr
*** 3761,3766 ****
--- 3774,3781 ----
      remote_enable_disable_tracepoint_feature, -1 },
    { "qXfer:fdpic:read", PACKET_DISABLE, remote_supported_packet,
      PACKET_qXfer_fdpic },
+   { "tracenz", PACKET_DISABLE,
+     remote_string_tracing_feature, -1 },
  };
  
  static char *remote_support_xml;
*************** remote_supports_enable_disable_tracepoin
*** 9704,9709 ****
--- 9719,9732 ----
    return rs->enable_disable_tracepoints;
  }
  
+ static int
+ remote_supports_string_tracing (void)
+ {
+   struct remote_state *rs = get_remote_state ();
+ 
+   return rs->string_tracing;
+ }
+ 
  static void
  remote_trace_init (void)
  {
*************** Specify the serial device it is connecte
*** 10421,10426 ****
--- 10444,10450 ----
    remote_ops.to_supports_non_stop = remote_supports_non_stop;
    remote_ops.to_supports_multi_process = remote_supports_multi_process;
    remote_ops.to_supports_enable_disable_tracepoint = remote_supports_enable_disable_tracepoint;
+   remote_ops.to_supports_string_tracing = remote_supports_string_tracing;
    remote_ops.to_trace_init = remote_trace_init;
    remote_ops.to_download_tracepoint = remote_download_tracepoint;
    remote_ops.to_download_trace_state_variable
Index: target.c
===================================================================
RCS file: /cvs/src/src/gdb/target.c,v
retrieving revision 1.285
diff -p -r1.285 target.c
*** target.c	6 Jun 2011 12:47:07 -0000	1.285
--- target.c	3 Oct 2011 15:34:17 -0000
*************** update_current_target (void)
*** 672,677 ****
--- 672,678 ----
        /* Do not inherit to_search_memory.  */
        INHERIT (to_supports_multi_process, t);
        INHERIT (to_supports_enable_disable_tracepoint, t);
+       INHERIT (to_supports_string_tracing, t);
        INHERIT (to_trace_init, t);
        INHERIT (to_download_tracepoint, t);
        INHERIT (to_download_trace_state_variable, t);
*************** update_current_target (void)
*** 840,845 ****
--- 841,849 ----
    de_fault (to_supports_enable_disable_tracepoint,
  	    (int (*) (void))
  	    return_zero);
+   de_fault (to_supports_string_tracing,
+ 	    (int (*) (void))
+ 	    return_zero);
    de_fault (to_trace_init,
  	    (void (*) (void))
  	    tcomplain);
Index: target.h
===================================================================
RCS file: /cvs/src/src/gdb/target.h,v
retrieving revision 1.212
diff -p -r1.212 target.h
*** target.h	27 Sep 2011 15:30:18 -0000	1.212
--- target.h	3 Oct 2011 15:34:17 -0000
*************** struct target_ops
*** 653,658 ****
--- 653,661 ----
         experiment is running?  */
      int (*to_supports_enable_disable_tracepoint) (void);
  
+     /* Does this target support the tracenz bytecode for string collection?  */
+     int (*to_supports_string_tracing) (void);
+ 
      /* Determine current architecture of thread PTID.
  
         The target is supposed to determine the architecture of the code where
*************** struct address_space *target_thread_addr
*** 894,899 ****
--- 897,905 ----
  #define target_supports_enable_disable_tracepoint() \
    (*current_target.to_supports_enable_disable_tracepoint) ()
  
+ #define target_supports_string_tracing() \
+   (*current_target.to_supports_string_tracing) ()
+ 
  /* Invalidate all target dcaches.  */
  extern void target_dcache_invalidate (void);
  
Index: tracepoint.c
===================================================================
RCS file: /cvs/src/src/gdb/tracepoint.c,v
retrieving revision 1.232
diff -p -r1.232 tracepoint.c
*** tracepoint.c	27 Sep 2011 13:09:36 -0000	1.232
--- tracepoint.c	3 Oct 2011 15:34:17 -0000
*************** teval_pseudocommand (char *args, int fro
*** 574,579 ****
--- 574,620 ----
    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.  */
+ 	  string_kludge = opts.print_max;
+ 	  exp++;
+ 	  if (*exp >= '0' && *exp <= '9')
+ 	    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);
+ 
+   while (*exp == ' ' || *exp == '\t')
+     exp++;
+ 
+   return exp;
+ }
+ 
  /* Enter a list of actions for a tracepoint.  */
  static void
  trace_actions_command (char *args, int from_tty)
*************** validate_actionline (char **line, struct
*** 656,661 ****
--- 697,706 ----
  
    if (cmd_cfunc_eq (c, collect_pseudocommand))
      {
+       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.  */
*************** encode_actions_1 (struct command_line *a
*** 1313,1318 ****
--- 1358,1367 ----
  
        if (cmd_cfunc_eq (cmd, collect_pseudocommand))
  	{
+ 	  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.  */
*************** trace_dump_actions (struct command_line 
*** 2581,2586 ****
--- 2630,2638 ----
  	     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.  */
Index: tracepoint.h
===================================================================
RCS file: /cvs/src/src/gdb/tracepoint.h,v
retrieving revision 1.43
diff -p -r1.43 tracepoint.h
*** tracepoint.h	25 Jul 2011 11:24:44 -0000	1.43
--- tracepoint.h	3 Oct 2011 15:34:17 -0000
*************** struct cleanup *make_cleanup_restore_cur
*** 212,217 ****
--- 212,220 ----
  struct cleanup *make_cleanup_restore_traceframe_number (void);
  
  void free_actions (struct breakpoint *);
+ 
+ extern char *decode_agent_options (char *exp);
+ 
  extern void validate_actionline (char **, struct breakpoint *);
  
  extern void end_actions_pseudocommand (char *args, int from_tty);
Index: gdbserver/server.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/server.c,v
retrieving revision 1.148
diff -p -r1.148 server.c
*** gdbserver/server.c	1 Sep 2011 03:14:10 -0000	1.148
--- gdbserver/server.c	3 Oct 2011 15:34:17 -0000
*************** handle_query (char *own_buf, int packet_
*** 1559,1565 ****
  	  strcat (own_buf, ";qXfer:statictrace:read+");
  	  strcat (own_buf, ";qXfer:traceframe-info:read+");
  	  strcat (own_buf, ";EnableDisableTracepoints+");
! 	}
  
        return;
      }
--- 1559,1566 ----
  	  strcat (own_buf, ";qXfer:statictrace:read+");
  	  strcat (own_buf, ";qXfer:traceframe-info:read+");
  	  strcat (own_buf, ";EnableDisableTracepoints+");
! 	  strcat (own_buf, ";tracenz+");
! }
  
        return;
      }
Index: gdbserver/tracepoint.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/tracepoint.c,v
retrieving revision 1.27
diff -p -r1.27 tracepoint.c
*** gdbserver/tracepoint.c	15 Sep 2011 22:54:13 -0000	1.27
--- gdbserver/tracepoint.c	3 Oct 2011 15:34:17 -0000
*************** static enum eval_result_type eval_agent_
*** 1209,1214 ****
--- 1209,1217 ----
  
  static int agent_mem_read (struct traceframe *tframe,
  			   unsigned char *to, CORE_ADDR from, ULONGEST len);
+ static int agent_mem_read_string (struct traceframe *tframe,
+ 				  unsigned char *to, CORE_ADDR from,
+ 				  ULONGEST len);
  static int agent_tsv_read (struct traceframe *tframe, int n);
  
  #ifndef IN_PROCESS_AGENT
*************** eval_agent_expr (struct tracepoint_hit_c
*** 4651,4656 ****
--- 4654,4666 ----
  	  agent_tsv_read (tframe, arg);
  	  break;
  
+ 	case gdb_agent_op_tracenz:
+ 	  agent_mem_read_string (tframe, NULL, (CORE_ADDR) stack[--sp],
+ 				 (ULONGEST) top);
+ 	  if (--sp >= 0)
+ 	    top = stack[sp];
+ 	  break;
+ 
  	  /* GDB never (currently) generates any of these ops.  */
  	case gdb_agent_op_float:
  	case gdb_agent_op_ref_float:
*************** agent_mem_read (struct traceframe *tfram
*** 4734,4739 ****
--- 4744,4809 ----
    return 0;
  }
  
+ static int
+ agent_mem_read_string (struct traceframe *tframe,
+ 		       unsigned char *to, CORE_ADDR from, ULONGEST len)
+ {
+   unsigned char *buf, *mspace;
+   ULONGEST remaining = len;
+   unsigned short blocklen, i;
+ 
+   /* To save a bit of space, block lengths are 16-bit, so break large
+      requests into multiple blocks.  Bordering on overkill for strings,
+      but it could happen that someone specifies a large max length.  */
+   while (remaining > 0)
+     {
+       size_t sp;
+ 
+       blocklen = (remaining > 65535 ? 65535 : remaining);
+       /* We want working space to accumulate nonzero bytes, since
+ 	 traceframes must have a predecided size (otherwise it gets
+ 	 harder to wrap correctly for the circular case, etc).  */
+       buf = (unsigned char *) xmalloc (blocklen + 1);
+       for (i = 0; i < blocklen; ++i)
+ 	{
+ 	  /* Read the string one byte at a time, in case the string is
+ 	     at the end of a valid memory area - we don't want a
+ 	     correctly-terminated string to engender segvio
+ 	     complaints.  */
+ 	  read_inferior_memory (from + i, buf + i, 1);
+ 
+ 	  if (buf[i] == '\0')
+ 	    {
+ 	      blocklen = i + 1;
+ 	      /* Make sure outer loop stops now too.  */
+ 	      remaining = blocklen;
+ 	      break;
+ 	    }
+ 	}
+       sp = 1 + sizeof (from) + sizeof (blocklen) + blocklen;
+       mspace = add_traceframe_block (tframe, sp);
+       if (mspace == NULL)
+ 	{
+ 	  xfree (buf);
+ 	  return 1;
+ 	}
+       /* Identify block as a memory block.  */
+       *mspace = 'M';
+       ++mspace;
+       /* Record address and size.  */
+       memcpy ((void *) mspace, (void *) &from, sizeof (from));
+       mspace += sizeof (from);
+       memcpy ((void *) mspace, (void *) &blocklen, sizeof (blocklen));
+       mspace += sizeof (blocklen);
+       /* Copy the string contents.  */
+       memcpy ((void *) mspace, (void *) buf, blocklen);
+       remaining -= blocklen;
+       from += blocklen;
+       xfree (buf);
+     }
+   return 0;
+ }
+ 
  /* Record the value of a trace state variable.  */
  
  static int
Index: doc/agentexpr.texi
===================================================================
RCS file: /cvs/src/src/gdb/doc/agentexpr.texi,v
retrieving revision 1.15
diff -p -r1.15 agentexpr.texi
*** doc/agentexpr.texi	24 Feb 2011 07:38:00 -0000	1.15
--- doc/agentexpr.texi	3 Oct 2011 15:34:17 -0000
*************** named @code{trace_quick16}, for consiste
*** 489,494 ****
--- 489,499 ----
  Record the value of trace state variable number @var{n} in the trace
  buffer.  The handling of @var{n} is as described for @code{getv}.
  
+ @item @code{tracenz} (0x2f)  @var{addr} @var{size} @result{}
+ Record the bytes at @var{addr} in a trace buffer, for later retrieval
+ by GDB.  Stop at either the first zero byte, or when @var{size} bytes
+ have been recorded, whichever occurs first.
+ 
  @item @code{end} (0x27): @result{}
  Stop executing bytecode; the result should be the top element of the
  stack.  If the purpose of the expression was to compute an lvalue or a
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.865
diff -p -r1.865 gdb.texinfo
*** doc/gdb.texinfo	29 Sep 2011 02:25:49 -0000	1.865
--- doc/gdb.texinfo	3 Oct 2011 15:34:18 -0000
*************** end
*** 10268,10274 ****
  @end smallexample
  
  @kindex collect @r{(tracepoints)}
! @item collect @var{expr1}, @var{expr2}, @dots{}
  Collect values of the given expressions when the tracepoint is hit.
  This command accepts a comma-separated list of any valid expressions.
  In addition to global, static, or local variables, the following
--- 10268,10274 ----
  @end smallexample
  
  @kindex collect @r{(tracepoints)}
! @item collect@r{[}/@var{mods}@r{]} @var{expr1}, @var{expr2}, @dots{}
  Collect values of the given expressions when the tracepoint is hit.
  This command accepts a comma-separated list of any valid expressions.
  In addition to global, static, or local variables, the following
*************** You can give several consecutive @code{c
*** 10314,10319 ****
--- 10314,10328 ----
  with a single argument, or one @code{collect} command with several
  arguments separated by commas; the effect is the same.
  
+ The optional @var{mods} changes the usual handling of the arguments.
+ @code{s} requests that pointers to chars be handled as strings, in
+ particular collecting the contents of the memory being pointed at, up
+ to the first zero.  The upper bound is by default the value of the
+ @code{print elements} variable; if @code{s} is followed by a decimal
+ number, that is the upper bound instead.  So for instance
+ @samp{collect/s25 mystr} collects as many as 25 characters at
+ @samp{mystr}.
+ 
  The command @code{info scope} (@pxref{Symbols, info scope}) is
  particularly useful for figuring out what data to collect.
  
Index: common/ax.def
===================================================================
RCS file: /cvs/src/src/gdb/common/ax.def,v
retrieving revision 1.4
diff -p -r1.4 ax.def
*** common/ax.def	25 Feb 2011 14:21:05 -0000	1.4
--- common/ax.def	3 Oct 2011 15:34:19 -0000
*************** DEFOP (swap, 0, 0, 2, 2, 0x2b)
*** 86,93 ****
  DEFOP (getv, 2, 0, 0, 1, 0x2c)
  DEFOP (setv, 2, 0, 0, 1, 0x2d)
  DEFOP (tracev, 2, 0, 0, 1, 0x2e)
! /* We need something here just to make the tables come out ok.  */
! DEFOP (invalid, 0, 0, 0, 0, 0x2f)
  DEFOP (trace16, 2, 0, 1, 1, 0x30)
  /* We need something here just to make the tables come out ok.  */
  DEFOP (invalid2, 0, 0, 0, 0, 0x31)
--- 86,92 ----
  DEFOP (getv, 2, 0, 0, 1, 0x2c)
  DEFOP (setv, 2, 0, 0, 1, 0x2d)
  DEFOP (tracev, 2, 0, 0, 1, 0x2e)
! DEFOP (tracenz, 0, 0, 2, 0, 0x2f)
  DEFOP (trace16, 2, 0, 1, 1, 0x30)
  /* We need something here just to make the tables come out ok.  */
  DEFOP (invalid2, 0, 0, 0, 0, 0x31)