Ping: frozen variable objects

[Vladimir Prus <vladimir@codesourcery.com>]

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The frozen variable objects patch:

	http://thread.gmane.org/gmane.comp.gdb.patches/31838

seem to be unreviewed as yet. Here's a version that's
updated for the current mainline, no regressions. OK?

- Volodya



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        gdb/
	* varobj.h (varobj_set_frozen): New
	(varobj_get_frozen): New.
	(varobj_update): New parameter explicit.
	* varobj.c (struct varobj): New fields frozen
	and not_fetched.
	(varobj_set_frozen, varobj_get_frozen): New.
	(install_new_value): Don't fetch values for 
	frozen variable object, or children thereof.  Allow
	a frozen variable object to have non-fetched value.
	(varobj_update): Allow updating child variables.
	Don't traverse frozen children.
	(new_variable): Initialize the frozen field.
	(c_value_of_variable): Return NULL for frozen
	variable without any value yet. 
	* mi/mi-cmd-var.c (varobj_update_one): New parameter
	'explicit'.
	(mi_cmd_var_create): Output the 'frozen' field,
	as soon as testsuite is adjusted to expect that field.
	(mi_cmd_var_set_frozen): New.
	(mi_cmd_var_update): Pass the 'explicit' parameter to
	varobj_update_one.
	* mi/mi-cmds.c (mi_cmds): Register '-var-set-frozen'.
	* mi/mi-cmds.h (mi_cmd_var_set_frozen): Declare.

        doc/
        * gdb.texinfo (GDB/MI Variable Objects): Document
	frozen variables objects.

        testsuite/
	* gdb.mi/mi-var-cmd.exp: Delete varobjs left by previous
	tests. Run the frozen varobjs test.
	* gdb.mi/var-cmd.c (do_frozen_tests): New.
	* lib/mi-support.exp (mi_varobj_delete): New.
	(mi_varobj_update): Fix thinko.

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--- gdb/doc/gdb.texinfo	(/mirrors/gdb_mainline)	(revision 3540)
+++ gdb/doc/gdb.texinfo	(/patches/gdb/frozen/gdb_mainline)	(revision 3540)
@@ -19730,6 +19730,8 @@ access this functionality:
 @tab set the value of this variable
 @item @code{-var-update}
 @tab update the variable and its children
+@item @code{-var-set-frozen}
+@tab set frozeness attribute
 @end multitable
 
 In the next subsection we describe each operation in detail and suggest
--- gdb/testsuite/gdb.mi/mi-var-cmd.exp	(/mirrors/gdb_mainline)	(revision 3540)
+++ gdb/testsuite/gdb.mi/mi-var-cmd.exp	(/patches/gdb/frozen/gdb_mainline)	(revision 3540)
@@ -591,6 +591,20 @@ mi_gdb_test "-var-update selected_a" \
 	"\\^done,changelist=\\\[\{name=\"selected_a\",in_scope=\"true\",new_type=\"int\",new_num_children=\"0\"\}\\\]" \
 	"update selected_a in do_special_tests"
 
+mi_delete_varobj selected_a "delete selected_a"
+mi_delete_varobj array_ptr "delete array_ptr"
+
+proc set_frozen {varobjs flag} {
+    foreach v $varobjs {
+        mi_gdb_test "-var-set-frozen $v $flag" \
+            "\\^done" \
+            "-var-set-frozen $v $flag"
+    }
+}
+
+mi_prepare_inline_tests $srcfile
+mi_run_inline_test frozen
+
 # Test whether bad varobjs crash GDB.
 
 # A varobj we fail to read during -var-update should be considered
--- gdb/testsuite/gdb.mi/var-cmd.c	(/mirrors/gdb_mainline)	(revision 3540)
+++ gdb/testsuite/gdb.mi/var-cmd.c	(/patches/gdb/frozen/gdb_mainline)	(revision 3540)
@@ -315,6 +315,92 @@ do_special_tests (void)
   incr_a(2);
 }
 
+void do_frozen_tests ()
+{
+  /*: BEGIN: frozen :*/
+  struct {
+    int i;
+    struct {
+      int j;
+      int k;
+    } nested;
+  } v1 = {1, {2, 3}};
+
+  int v2 = 4;
+  /*: 
+    mi_create_varobj V1 v1 "create varobj for v1" 
+    mi_create_varobj V2 v2 "create varobj for v2"
+
+    mi_list_varobj_children "V1" {
+        {"V1.i" "i" "0" "int"}
+	{"V1.nested" "nested" "2" "struct {...}"}
+    } "list children of v1"
+
+    mi_list_varobj_children "V1.nested" {
+        {"V1.nested.j" "j" "0" "int"}
+        {"V1.nested.k" "k" "0" "int"}
+    } "list children of v1.nested"
+
+    mi_check_varobj_value V1.i 1 "check V1.i: 1"
+    mi_check_varobj_value V1.nested.j 2 "check V1.nested.j: 2"
+    mi_check_varobj_value V1.nested.k 3 "check V1.nested.j: 3"
+    mi_check_varobj_value V2 4 "check V2: 4"
+  :*/
+  v2 = 5;
+  /*: 
+    mi_varobj_update * {V2} "update varobjs: V2 changed"
+    set_frozen V2 1
+  :*/
+  v2 = 6;
+  /*: 
+    mi_varobj_update * {} "update varobjs: nothing changed"
+    mi_check_varobj_value V2 5 "check V2: 5"
+    mi_varobj_update V2 {V2} "update V2 explicitly"
+    mi_check_varobj_value V2 6 "check V2: 6"
+  :*/
+  v1.i = 7;
+  v1.nested.j = 8;
+  v1.nested.k = 9;
+  /*:
+    set_frozen V1 1
+    mi_varobj_update * {} "update varobjs: nothing changed"
+    mi_check_varobj_value V1.i 1 "check V1.i: 1"
+    mi_check_varobj_value V1.nested.j 2 "check V1.nested.j: 2"
+    mi_check_varobj_value V1.nested.k 3 "check V1.nested.j: 3"    
+    # Check that explicit update for elements of structures
+    # works.
+    # Update v1.j
+    mi_varobj_update V1.nested.j {V1.nested.j} "update V1.nested.j"
+    mi_check_varobj_value V1.i 1 "check V1.i: 1"
+    mi_check_varobj_value V1.nested.j 8 "check V1.nested.j: 8"
+    mi_check_varobj_value V1.nested.k 3 "check V1.nested.j: 3"    
+    # Update v1.nested, check that children is updated.
+    mi_varobj_update V1.nested {V1.nested.k} "update V1.nested"
+    mi_check_varobj_value V1.i 1 "check V1.i: 1"
+    mi_check_varobj_value V1.nested.j 8 "check V1.nested.j: 8"
+    mi_check_varobj_value V1.nested.k 9 "check V1.nested.j: 9"    
+    # Update v1.i
+    mi_varobj_update V1.i {V1.i} "update V1.i"
+    mi_check_varobj_value V1.i 7 "check V1.i: 7"
+  :*/
+  v1.i = 10;
+  v1.nested.j = 11;
+  v1.nested.k = 12;
+  /*:
+    # Check that unfreeze itself does not updates the values.
+    set_frozen V1 0
+    mi_check_varobj_value V1.i 7 "check V1.i: 7"
+    mi_check_varobj_value V1.nested.j 8 "check V1.nested.j: 8"
+    mi_check_varobj_value V1.nested.k 9 "check V1.nested.j: 9"    
+    mi_varobj_update V1 {V1.i V1.nested.j V1.nested.k} "update V1"
+    mi_check_varobj_value V1.i 10 "check V1.i: 10"
+    mi_check_varobj_value V1.nested.j 11 "check V1.nested.j: 11"
+    mi_check_varobj_value V1.nested.k 12 "check V1.nested.j: 12"    
+  :*/    
+  
+  /*: END: frozen :*/
+}
+
 int
 main (int argc, char *argv [])
 {
@@ -322,6 +408,7 @@ main (int argc, char *argv [])
   do_block_tests ();
   do_children_tests ();
   do_special_tests ();
+  do_frozen_tests ();
   exit (0);
 }
 
--- gdb/testsuite/lib/mi-support.exp	(/mirrors/gdb_mainline)	(revision 3540)
+++ gdb/testsuite/lib/mi-support.exp	(/patches/gdb/frozen/gdb_mainline)	(revision 3540)
@@ -1039,8 +1039,9 @@ proc mi_varobj_update { name expected te
     set first 1
     foreach item $expected {
         set v "{name=\"$item\",in_scope=\"true\",type_changed=\"false\"}"
-        if {$first} {
+        if {$first == 1} {
             set er "$er$v"
+            set first 0
         } else {
             set er "$er,$v"
         }
@@ -1239,11 +1240,11 @@ proc mi_send_resuming_command {command t
 # be determined.
 # Does not check that the line is the same as requested.
 # The caller can check itself if required.
-proc mi_continue_to_line {location command} {
+proc mi_continue_to_line {location} {
 
     mi_tbreak $location   
     mi_send_resuming_command "exec-continue" "run to $location (exec-continue)"
-    return [mi_wait_for_stop]
+    return [mi_wait_for_stop "continue to $location"]
 }
 
 # Wait until gdb prints the current line.

Property changes on: gdb/testsuite/lib
___________________________________________________________________
Name: svk:merge
 +d48a11ec-ee1c-0410-b3f5-c20844f99675:/patches/gdb/frozen/gdb_mainline/gdb/testsuite/lib:2741

--- gdb/mi/mi-cmds.h	(/mirrors/gdb_mainline)	(revision 3540)
+++ gdb/mi/mi-cmds.h	(/patches/gdb/frozen/gdb_mainline)	(revision 3540)
@@ -113,6 +113,7 @@ extern mi_cmd_argv_ftype mi_cmd_var_info
 extern mi_cmd_argv_ftype mi_cmd_var_info_type;
 extern mi_cmd_argv_ftype mi_cmd_var_list_children;
 extern mi_cmd_argv_ftype mi_cmd_var_set_format;
+extern mi_cmd_argv_ftype mi_cmd_var_set_frozen;
 extern mi_cmd_argv_ftype mi_cmd_var_show_attributes;
 extern mi_cmd_argv_ftype mi_cmd_var_show_format;
 extern mi_cmd_argv_ftype mi_cmd_var_update;
--- gdb/mi/mi-cmds.c	(/mirrors/gdb_mainline)	(revision 3540)
+++ gdb/mi/mi-cmds.c	(/patches/gdb/frozen/gdb_mainline)	(revision 3540)
@@ -156,6 +156,7 @@ struct mi_cmd mi_cmds[] =
   { "var-info-type", { NULL, 0 }, 0, mi_cmd_var_info_type},
   { "var-list-children", { NULL, 0 }, 0, mi_cmd_var_list_children},
   { "var-set-format", { NULL, 0 }, 0, mi_cmd_var_set_format},
+  { "var-set-frozen", { NULL, 0 }, 0, mi_cmd_var_set_frozen},
   { "var-show-attributes", { NULL, 0 }, 0, mi_cmd_var_show_attributes},
   { "var-show-format", { NULL, 0 }, 0, mi_cmd_var_show_format},
   { "var-update", { NULL, 0 }, 0, mi_cmd_var_update},
--- gdb/mi/mi-cmd-var.c	(/mirrors/gdb_mainline)	(revision 3540)
+++ gdb/mi/mi-cmd-var.c	(/patches/gdb/frozen/gdb_mainline)	(revision 3540)
@@ -37,7 +37,8 @@ const char mi_all_values[] = "--all-valu
 extern int varobjdebug;		/* defined in varobj.c.  */
 
 static void varobj_update_one (struct varobj *var,
-			      enum print_values print_values);
+			      enum print_values print_values,
+			      int explicit);
 
 static int mi_print_value_p (struct type *type, enum print_values print_values);
 
@@ -64,6 +65,9 @@ print_varobj (struct varobj *var, enum p
       ui_out_field_string (uiout, "type", type);
       xfree (type);
     }
+
+  if (varobj_get_frozen (var))
+    ui_out_field_int (uiout, "frozen", 1);
 }
 
 /* VAROBJ operations */
@@ -233,6 +237,35 @@ mi_cmd_var_set_format (char *command, ch
 }
 
 enum mi_cmd_result
+mi_cmd_var_set_frozen (char *command, char **argv, int argc)
+{
+  struct varobj *var;
+  int frozen;
+
+  if (argc != 2)
+    error (_("mi_cmd_var_set_format: Usage: NAME FROZEN_FLAG."));
+
+  var = varobj_get_handle (argv[0]);
+  if (var == NULL)
+    error (_("Variable object not found"));
+
+  if (strcmp (argv[1], "0") == 0)
+    frozen = 0;
+  else if (strcmp (argv[1], "1") == 0)
+    frozen = 1;
+  else
+    error (_("Invalid flag value"));
+
+  varobj_set_frozen (var, frozen);
+
+  /* We don't automatically return the new value, or what varobjs got new
+     values during unfreezing.  If this information is required, client
+     should call -var-update explicitly.  */
+  return MI_CMD_DONE;
+}
+
+
+enum mi_cmd_result
 mi_cmd_var_show_format (char *command, char **argv, int argc)
 {
   enum varobj_display_formats format;
@@ -513,7 +546,7 @@ mi_cmd_var_update (char *command, char *
       cr = rootlist;
       while (*cr != NULL)
 	{
-	  varobj_update_one (*cr, print_values);
+	  varobj_update_one (*cr, print_values, 0 /* implicit */);
 	  cr++;
 	}
       do_cleanups (cleanup);
@@ -529,7 +562,7 @@ mi_cmd_var_update (char *command, char *
         cleanup = make_cleanup_ui_out_tuple_begin_end (uiout, "changelist");
       else
         cleanup = make_cleanup_ui_out_list_begin_end (uiout, "changelist");
-      varobj_update_one (var, print_values);
+      varobj_update_one (var, print_values, 1 /* explicit */);
       do_cleanups (cleanup);
     }
     return MI_CMD_DONE;
@@ -538,14 +571,15 @@ mi_cmd_var_update (char *command, char *
 /* Helper for mi_cmd_var_update().  */
 
 static void
-varobj_update_one (struct varobj *var, enum print_values print_values)
+varobj_update_one (struct varobj *var, enum print_values print_values,
+		   int explicit)
 {
   struct varobj **changelist;
   struct varobj **cc;
   struct cleanup *cleanup = NULL;
   int nc;
 
-  nc = varobj_update (&var, &changelist);
+  nc = varobj_update (&var, &changelist, explicit);
 
   /* nc >= 0  represents the number of changes reported into changelist.
      nc < 0   means that an error occured or the the variable has 
--- gdb/varobj.c	(/mirrors/gdb_mainline)	(revision 3540)
+++ gdb/varobj.c	(/patches/gdb/frozen/gdb_mainline)	(revision 3540)
@@ -137,6 +137,16 @@ struct varobj
 
   /* Last print value.  */
   char *print_value;
+
+  /* Is this variable frozen. Frozen variables are never implicitly
+     updated by -var-update * or -var-update <direct-or-indirect-parent>.
+  */
+  int frozen;
+
+  /* Is the value of this variable intentionally not fetched?  It is
+     not fetched if either the variable is frozen, or any parents is
+     frozen.  */
+  int not_fetched;
 };
 
 struct cpstack
@@ -665,6 +675,26 @@ varobj_get_display_format (struct varobj
   return var->format;
 }
 
+void
+varobj_set_frozen (struct varobj *var, int frozen)
+{
+  /* When a variable is unfrozen, we don't fetch its value.
+     The 'not_fetched' flag remains set, so next -var-update
+     won't complain.
+
+     We don't fetch the value, because for structures the client
+     should do -var-update anyway.  It would be bad to have different
+     client-size logic for structure and other types.  */
+  var->frozen = frozen;
+}
+
+int
+varobj_get_frozen (struct varobj *var)
+{
+  return var->frozen;
+}
+
+
 int
 varobj_get_num_children (struct varobj *var)
 {
@@ -911,6 +941,7 @@ install_new_value (struct varobj *var, s
   int changeable;
   int need_to_fetch;
   int changed = 0;
+  int intentionally_not_fetched = 0;
 
   /* We need to know the varobj's type to decide if the value should
      be fetched or not.  C++ fake children (public/protected/private) don't have
@@ -943,10 +974,23 @@ install_new_value (struct varobj *var, s
   /* The new value might be lazy.  If the type is changeable,
      that is we'll be comparing values of this type, fetch the
      value now.  Otherwise, on the next update the old value
-     will be lazy, which means we've lost that old value.  */
+     will be lazy, which means we've lost that old value.  */     
   if (need_to_fetch && value && value_lazy (value))
     {
-      if (!gdb_value_fetch_lazy (value))
+      struct varobj *parent = var->parent;
+      int frozen = var->frozen;
+      for (; !frozen && parent; parent = parent->parent)
+	frozen |= parent->frozen;
+
+      if (frozen && initial)
+	{
+	  /* For variables that are frozen, or are children of frozen
+	     variables, we don't do fetch on initial assignment.
+	     For non-initial assignemnt we do the fetch, since it means we're
+	     explicitly asked to compare the new value with the old one.  */
+	  intentionally_not_fetched = 1;
+	}
+      else if (!gdb_value_fetch_lazy (value))
 	{
 	  /* Set the value to NULL, so that for the next -var-update,
 	     we don't try to compare the new value with this value,
@@ -976,41 +1020,56 @@ install_new_value (struct varobj *var, s
 	{
 	  /* Try to compare the values.  That requires that both
 	     values are non-lazy.  */
-	  
-	  /* Quick comparison of NULL values.  */
-	  if (var->value == NULL && value == NULL)
-	    /* Equal. */
-	    ;
-	  else if (var->value == NULL || value == NULL)
+	  if (var->not_fetched && value_lazy (var->value))
 	    {
-	      xfree (var->print_value);
-	      var->print_value = value_get_print_value (value, var->format);
+	      /* This is a frozen varobj and the value was never read.
+		 Presumably, UI shows some "never read" indicator.
+		 Now that we've fetched the real value, we need to report
+		 this varobj as changed so that UI can show the real
+		 value.  */
 	      changed = 1;
 	    }
-	  else
+          else
 	    {
-	      char *print_value;
-	      gdb_assert (!value_lazy (var->value));
-	      gdb_assert (!value_lazy (value));
-	      print_value = value_get_print_value (value, var->format);
-
-	      gdb_assert (var->print_value != NULL && print_value != NULL);
-	      if (strcmp (var->print_value, print_value) != 0)
+	      /* Quick comparison of NULL values.  */
+	      if (var->value == NULL && value == NULL)
+		/* Equal. */
+		;
+	      else if (var->value == NULL || value == NULL)
 		{
 		  xfree (var->print_value);
-		  var->print_value = print_value;
+		  var->print_value = value_get_print_value (value, var->format);
 		  changed = 1;
 		}
 	      else
-		xfree (print_value);
+		{
+		  char *print_value;
+		  gdb_assert (!value_lazy (var->value));
+		  gdb_assert (!value_lazy (value));
+		  print_value = value_get_print_value (value, var->format);
+		  
+		  gdb_assert (var->print_value != NULL && print_value != NULL);
+		  if (strcmp (var->print_value, print_value) != 0)
+		    {
+		      xfree (var->print_value);
+		      var->print_value = print_value;
+		      changed = 1;
+		    }
+		  else
+		    xfree (print_value);
+		}
 	    }
 	}
     }
 
   /* We must always keep the new value, since children depend on it.  */
-  if (var->value != NULL)
+  if (var->value != NULL && var->value != value)
     value_free (var->value);
   var->value = value;
+  if (value && value_lazy (value) && intentionally_not_fetched)
+    var->not_fetched = 1;
+  else
+    var->not_fetched = 0;
   var->updated = 0;
 
   gdb_assert (!var->value || value_type (var->value));
@@ -1027,17 +1086,21 @@ install_new_value (struct varobj *var, s
     < 0 for error values, see varobj.h.
     Otherwise it is the number of children + parent changed.
 
-   Only root variables can be updated... 
+   The EXPLICIT parameter specifies if this call is result
+   of MI request to update this specific variable, or 
+   result of implicit -var-update *. For implicit request, we don't
+   update frozen variables.
 
    NOTE: This function may delete the caller's varobj. If it
    returns TYPE_CHANGED, then it has done this and VARP will be modified
    to point to the new varobj.  */
 
 int
-varobj_update (struct varobj **varp, struct varobj ***changelist)
+varobj_update (struct varobj **varp, struct varobj ***changelist,
+	       int explicit)
 {
   int changed = 0;
-  int type_changed;
+  int type_changed = 0;
   int i;
   int vleft;
   struct varobj *v;
@@ -1052,48 +1115,56 @@ varobj_update (struct varobj **varp, str
   /* sanity check: have we been passed a pointer?  */
   gdb_assert (changelist);
 
-  if (!is_root_p (*varp))
-    error (_("Only root variables can be updated"));
+  /* Frozen means frozen -- we don't check for any change in
+     this varobj, including its going out of scope, or
+     changing type.  One use case for frozen varobjs is
+     retaining previously evaluated expressions, and we don't
+     want them to be reevaluated at all.  */
+  if (!explicit && (*varp)->frozen)
+    return 0;
 
   if (!(*varp)->root->is_valid)
     return INVALID;
 
-  /* Save the selected stack frame, since we will need to change it
-     in order to evaluate expressions.  */
-  old_fid = get_frame_id (deprecated_safe_get_selected_frame ());
-
-  /* Update the root variable. value_of_root can return NULL
-     if the variable is no longer around, i.e. we stepped out of
-     the frame in which a local existed. We are letting the 
-     value_of_root variable dispose of the varobj if the type
-     has changed.  */
-  type_changed = 1;
-  new = value_of_root (varp, &type_changed);
-
-  /* Restore selected frame.  */
-  fi = frame_find_by_id (old_fid);
-  if (fi)
-    select_frame (fi);
-
-  /* If this is a "use_selected_frame" varobj, and its type has changed,
-     them note that it's changed.  */
-  if (type_changed)
-    VEC_safe_push (varobj_p, result, *varp);
-
-  if (install_new_value ((*varp), new, type_changed))
+  if ((*varp)->root->rootvar == *varp)
     {
-      /* If type_changed is 1, install_new_value will never return
-	 non-zero, so we'll never report the same variable twice.  */
-      gdb_assert (!type_changed);
-      VEC_safe_push (varobj_p, result, *varp);
-    }
+      /* Save the selected stack frame, since we will need to change it
+	 in order to evaluate expressions.  */
+      old_fid = get_frame_id (deprecated_safe_get_selected_frame ());
+      
+      /* Update the root variable. value_of_root can return NULL
+	 if the variable is no longer around, i.e. we stepped out of
+	 the frame in which a local existed. We are letting the 
+	 value_of_root variable dispose of the varobj if the type
+	 has changed.  */
+      type_changed = 1;
+      new = value_of_root (varp, &type_changed);
 
-  if (new == NULL)
-    {
-      /* This means the varobj itself is out of scope.
-	 Report it.  */
-      VEC_free (varobj_p, result);
-      return NOT_IN_SCOPE;
+      /* Restore selected frame.  */
+      fi = frame_find_by_id (old_fid);
+      if (fi)
+	select_frame (fi);
+      
+      /* If this is a "use_selected_frame" varobj, and its type has changed,
+	 them note that it's changed.  */
+      if (type_changed)
+	VEC_safe_push (varobj_p, result, *varp);
+      
+        if (install_new_value ((*varp), new, type_changed))
+	  {
+	    /* If type_changed is 1, install_new_value will never return
+	       non-zero, so we'll never report the same variable twice.  */
+	    gdb_assert (!type_changed);
+	    VEC_safe_push (varobj_p, result, *varp);
+	  }
+
+      if (new == NULL)
+	{
+	  /* This means the varobj itself is out of scope.
+	     Report it.  */
+	  VEC_free (varobj_p, result);
+	  return NOT_IN_SCOPE;
+	}
     }
 
   VEC_safe_push (varobj_p, stack, *varp);
@@ -1111,13 +1182,13 @@ varobj_update (struct varobj **varp, str
 	{
 	  varobj_p c = VEC_index (varobj_p, v->children, i);
 	  /* Child may be NULL if explicitly deleted by -var-delete.  */
-	  if (c != NULL)
+	  if (c != NULL && !c->frozen)
 	    VEC_safe_push (varobj_p, stack, c);
 	}
-
+      
       /* Update this variable, unless it's a root, which is already
 	 updated.  */
-      if (v != *varp)
+      if (v->root->rootvar != v)
 	{	  
 	  new = value_of_child (v->parent, v->index);
 	  if (install_new_value (v, new, 0 /* type not changed */))
@@ -1399,6 +1470,8 @@ new_variable (void)
   var->root = NULL;
   var->updated = 0;
   var->print_value = NULL;
+  var->frozen = 0;
+  var->not_fetched = 0;
 
   return var;
 }
@@ -2112,6 +2185,12 @@ c_value_of_variable (struct varobj *var)
 	  }
 	else
 	  {
+	    if (var->not_fetched && value_lazy (var->value))
+	      /* Frozen variable and no value yet.  We don't
+		 implicitly fetch the value.  MI response will
+		 use empty string for the value, which is OK.  */
+	      return NULL;
+
 	    gdb_assert (varobj_value_is_changeable_p (var));
 	    gdb_assert (!value_lazy (var->value));
 	    return value_get_print_value (var->value, var->format);
@@ -2306,7 +2385,7 @@ cplus_describe_child (struct varobj *par
 
 	  if (cvalue && value)
 	    {
-	      *cvalue = value_cast (TYPE_FIELD_TYPE (type, index), value);
+              *cvalue = value_cast (TYPE_FIELD_TYPE (type, index), value);
 	    }
 
 	  if (ctype)
--- gdb/varobj.h	(/mirrors/gdb_mainline)	(revision 3540)
+++ gdb/varobj.h	(/patches/gdb/frozen/gdb_mainline)	(revision 3540)
@@ -86,6 +86,10 @@ extern enum varobj_display_formats varob
 extern enum varobj_display_formats varobj_get_display_format (
 							struct varobj *var);
 
+extern void varobj_set_frozen (struct varobj *var, int frozen);
+
+extern int varobj_get_frozen (struct varobj *var);
+
 extern int varobj_get_num_children (struct varobj *var);
 
 extern int varobj_list_children (struct varobj *var,
@@ -105,7 +109,8 @@ extern int varobj_set_value (struct varo
 
 extern int varobj_list (struct varobj ***rootlist);
 
-extern int varobj_update (struct varobj **varp, struct varobj ***changelist);
+extern int varobj_update (struct varobj **varp, struct varobj ***changelist,
+			  int explicit);
 
 extern void varobj_invalidate (void);
 

Property changes on: 
___________________________________________________________________
Name: csl:base
 +/all/mirrors/gdb_mainline
Name: svk:merge
 +d48a11ec-ee1c-0410-b3f5-c20844f99675:/patches/gdb/mi_continue_to/gdb_mainline:2736
 +d48a11ec-ee1c-0410-b3f5-c20844f99675:/patches/gdb/mi_inline_tests/gdb_mainline:3051
 +d48a11ec-ee1c-0410-b3f5-c20844f99675:/patches/gdb/varobj_doc/gdb_mainline:3074
 +e7755896-6108-0410-9592-8049d3e74e28:/mirrors/gdb/trunk:166548