Add options to skip unavailable locals

This is the patch to add new option '--skip-unavailable' to MI
commands '-stack-list-{locals, arguments, variables}'.  This patch
extends list_args_or_locals to add a new parameter 'skip_unavailable',
and don't list locals or arguments if values are unavailable and
'skip_unavailable' is true.

This is inspecting a trace frame (tfind mode), where only a few
locals have been collected.

-stack-list-locals, no switch vs new switch:

 -stack-list-locals --simple-values
 ^done,locals=[{name="array",type="unsigned char [2]"},{name="i",type="int",value="<unavailable>"}]
 -stack-list-locals --skip-unavailable --simple-values
 ^done,locals=[{name="array",type="unsigned char [2]"}]

-stack-list-arguments, no switch vs new switch:

 -stack-list-arguments --simple-values
 ^done,stack-args=[frame={level="0",args=[{name="j",type="int",value="4"},{name="s",type="char *",value="<unavailable>"}]},frame={level="1",args=[]}]
 -stack-list-arguments --skip-unavailable --simple-values
 ^done,stack-args=[frame={level="0",args=[{name="j",type="int",value="4"}]},frame={level="1",args=[]}]

-stack-list-variables, no switch vs new switch:

 -stack-list-variables --simple-values
 ^done,variables=[{name="j",arg="1",type="int",value="4"},{name="s",arg="1",type="char *",value="<unavailable>"},{name="array",type="unsigned char [2]"},{name="i",type="int",value="<unavailable>"}]
 -stack-list-variables --skip-unavailable --simple-values
 ^done,variables=[{name="j",arg="1",type="int",value="4"},{name="array",type="unsigned char [2]"}]

tests are added to test these new options.

gdb:

2013-08-27  Pedro Alves  <pedro@codesourcery.com>
	    Yao Qi  <yao@codesourcery.com>

	* mi/mi-cmd-stack.c (list_args_or_locals): Adjust prototype.
	(parse_no_frames_option): Remove.
	(mi_cmd_stack_list_locals): Handle --skip-unavailable.
	(mi_cmd_stack_list_args): Adjust.
	(mi_cmd_stack_list_variables): Handle --skip-unavailable.
	(list_arg_or_local): Add new parameter 'skip_unavailable'.  Return
	early if SKIP_UNAVAILABLE is true and ARG->val is unavailable.
	Caller update.
	(list_args_or_locals): New parameter 'skip_unavailable'.
	Handle it.
	* valprint.c (scalar_type_p): Rename to ...
	(val_print_scalar_type_p): ... this.  Make extern.
	(val_print, value_check_printable): Adjust.
	* valprint.h (val_print_scalar_type_p): Declare.
	* value.c (value_entirely_unavailable): New function.
	* value.h (value_entirely_unavailable): Declare.

	* NEWS: Mention the new option "--skip-unavailable" to MI
	commands '-stack-list-locals', '-stack-list-arguments' and
	'-stack-list-variables'.

gdb/doc:

2013-08-27  Pedro Alves  <pedro@codesourcery.com>
	    Yao Qi  <yao@codesourcery.com>

	* gdb.texinfo (GDB/MI Stack Manipulation) <-stack-list-locals>:
	Document new --skip-unavailable option.
	<-stack-list-variables>: Document new --skip-unavailable option.

gdb/testsuite:

2013-08-27  Yao Qi  <yao@codesourcery.com>

	* gdb.trace/entry-values.exp: Test unavailable entry value is
	not shown when option '--skip-unavailable' is specified.
	* gdb.trace/mi-trace-unavailable.exp (test_trace_unavailable):
	Add tests for new option '--skip-unavailable'.

gdb/ChangeLog

@@ -1,3 +1,27 @@
+2013-08-27  Pedro Alves  <pedro@codesourcery.com>
+	    Yao Qi  <yao@codesourcery.com>
+
+	* mi/mi-cmd-stack.c (list_args_or_locals): Adjust prototype.
+	(parse_no_frames_option): Remove.
+	(mi_cmd_stack_list_locals): Handle --skip-unavailable.
+	(mi_cmd_stack_list_args): Adjust.
+	(mi_cmd_stack_list_variables): Handle --skip-unavailable.
+	(list_arg_or_local): Add new parameter 'skip_unavailable'.  Return
+	early if SKIP_UNAVAILABLE is true and ARG->val is unavailable.
+	Caller update.
+	(list_args_or_locals): New parameter 'skip_unavailable'.
+	Handle it.
+	* valprint.c (scalar_type_p): Rename to ...
+	(val_print_scalar_type_p): ... this.  Make extern.
+	(val_print, value_check_printable): Adjust.
+	* valprint.h (val_print_scalar_type_p): Declare.
+	* value.c (value_entirely_unavailable): New function.
+	* value.h (value_entirely_unavailable): Declare.
+
+	* NEWS: Mention the new option "--skip-unavailable" to MI
+	commands '-stack-list-locals', '-stack-list-arguments' and
+	'-stack-list-variables'.
+
 2013-08-27  Yao Qi  <yao@codesourcery.com>
 
 	* mi/mi-cmd-stack.c (parse_no_frames_option): Remove.

gdb/NEWS

@@ -93,6 +93,10 @@ show range-stepping
   ** The new command -trace-frame-collected dumps collected variables,
      computed expressions, tvars, memory and registers in a traceframe.
 
+  ** The commands -stack-list-locals, -stack-list-arguments and
+     -stack-list-variables now accept an option "--skip-unavailable".
+     When used, only the available locals or arguments are displayed.
+
 * New system-wide configuration scripts
   A GDB installation now provides scripts suitable for use as system-wide
   configuration scripts for the following systems:

gdb/doc/ChangeLog

@@ -1,3 +1,10 @@
+2013-08-27  Pedro Alves  <pedro@codesourcery.com>
+	    Yao Qi  <yao@codesourcery.com>
+
+	* gdb.texinfo (GDB/MI Stack Manipulation) <-stack-list-locals>:
+	Document new --skip-unavailable option.
+	<-stack-list-variables>: Document new --skip-unavailable option.
+
 2013-08-26  Doug Evans  <dje@google.com>
 
 	* gdb.texinfo (Maintenance Commands): "maint print objfiles" now takes

gdb/doc/gdb.texinfo

@@ -31249,7 +31249,7 @@ For a stack with frame levels 0 through 11:
 @subsubheading Synopsis
 
 @smallexample
- -stack-list-arguments [ --no-frame-filters ] @var{print-values}
+ -stack-list-arguments [ --no-frame-filters ] [ --skip-unavailable ] @var{print-values}
     [ @var{low-frame} @var{high-frame} ]
 @end smallexample
 
@@ -31269,6 +31269,9 @@ type and value for simple data types, and the name and type for arrays,
 structures and unions.  If the option @code{--no-frame-filters} is
 supplied, then Python frame filters will not be executed.
 
+If the @code{--skip-unavailable} option is specified, arguments that
+are not available are not listed.  Partially available arguments
+are still displayed, however.
 
 Use of this command to obtain arguments in a single frame is
 deprecated in favor of the @samp{-stack-list-variables} command.
@@ -31453,7 +31456,7 @@ Show a single frame:
 @subsubheading Synopsis
 
 @smallexample
- -stack-list-locals [ --no-frame-filters ] @var{print-values}
+ -stack-list-locals [ --no-frame-filters ] [ --skip-unavailable ] @var{print-values}
 @end smallexample
 
 Display the local variable names for the selected frame.  If
@@ -31467,6 +31470,10 @@ other data types when the user wishes to explore their values in
 more detail.  If the option @code{--no-frame-filters} is supplied, then
 Python frame filters will not be executed.
 
+If the @code{--skip-unavailable} option is specified, local variables
+that are not available are not listed.  Partially available local
+variables are still displayed, however.
+
 This command is deprecated in favor of the
 @samp{-stack-list-variables} command.
 
@@ -31497,7 +31504,7 @@ This command is deprecated in favor of the
 @subsubheading Synopsis
 
 @smallexample
- -stack-list-variables [ --no-frame-filters ] @var{print-values}
+ -stack-list-variables [ --no-frame-filters ] [ --skip-unavailable ] @var{print-values}
 @end smallexample
 
 Display the names of local variables and function arguments for the selected frame.  If
@@ -31508,6 +31515,10 @@ type and value for simple data types, and the name and type for arrays,
 structures and unions.  If the option @code{--no-frame-filters} is
 supplied, then Python frame filters will not be executed.
 
+If the @code{--skip-unavailable} option is specified, local variables
+and arguments that are not available are not listed.  Partially
+available arguments and local variables are still displayed, however.
+
 @subsubheading Example
 
 @smallexample

gdb/mi/mi-cmd-stack.c

@@ -41,7 +41,8 @@ enum what_to_list { locals, arguments, all };
 
 static void list_args_or_locals (enum what_to_list what,
 				 enum print_values values,
-				 struct frame_info *fi);
+				 struct frame_info *fi,
+				 int skip_unavailable);
 
 /* True if we want to allow Python-based frame filters.  */
 static int frame_filters = 0;
@@ -202,17 +203,21 @@ mi_cmd_stack_list_locals (char *command, char **argv, int argc)
   enum py_bt_status result = PY_BT_ERROR;
   int print_value;
   int oind = 0;
+  int skip_unavailable = 0;
+  int i;
 
   if (argc > 1)
     {
       int i;
       enum opt
       {
-	NO_FRAME_FILTERS
+	NO_FRAME_FILTERS,
+	SKIP_UNAVAILABLE,
       };
       static const struct mi_opt opts[] =
 	{
 	  {"-no-frame-filters", NO_FRAME_FILTERS, 0},
+	  {"-skip-unavailable", SKIP_UNAVAILABLE, 0},
 	  { 0, 0, 0 }
 	};
 
@@ -229,6 +234,8 @@ mi_cmd_stack_list_locals (char *command, char **argv, int argc)
 	    {
 	    case NO_FRAME_FILTERS:
 	      raw_arg = oind;
+	    case SKIP_UNAVAILABLE:
+	      skip_unavailable = 1;
 	      break;
 	    }
 	}
@@ -237,7 +244,8 @@ mi_cmd_stack_list_locals (char *command, char **argv, int argc)
   /* After the last option is parsed, there should be only
      'print-values'.  */
   if (argc - oind != 1)
-    error (_("-stack-list-locals: Usage: [--no-frame-filters] PRINT_VALUES"));
+    error (_("-stack-list-locals: Usage: [--no-frame-filters] "
+	     "[--skip-unavailable] PRINT_VALUES"));
 
   frame = get_selected_frame (NULL);
   print_value = mi_parse_print_values (argv[oind]);
@@ -254,7 +262,8 @@ mi_cmd_stack_list_locals (char *command, char **argv, int argc)
       if "--no-frame-filters" has been specified from the command.  */
    if (! frame_filters || raw_arg  || result == PY_BT_NO_FILTERS)
      {
-       list_args_or_locals (locals, print_value, frame);
+       list_args_or_locals (locals, print_value, frame,
+			    skip_unavailable);
      }
 }
 
@@ -274,14 +283,17 @@ mi_cmd_stack_list_args (char *command, char **argv, int argc)
   struct ui_out *uiout = current_uiout;
   int raw_arg = 0;
   int oind = 0;
+  int skip_unavailable = 0;
   enum py_bt_status result = PY_BT_ERROR;
   enum opt
   {
     NO_FRAME_FILTERS,
+    SKIP_UNAVAILABLE,
   };
   static const struct mi_opt opts[] =
     {
       {"-no-frame-filters", NO_FRAME_FILTERS, 0},
+      {"-skip-unavailable", SKIP_UNAVAILABLE, 0},
       { 0, 0, 0 }
     };
 
@@ -298,12 +310,16 @@ mi_cmd_stack_list_args (char *command, char **argv, int argc)
 	case NO_FRAME_FILTERS:
 	  raw_arg = oind;
 	  break;
+	case SKIP_UNAVAILABLE:
+	  skip_unavailable = 1;
+	  break;
 	}
     }
 
   if (argc - oind != 1 && argc - oind != 3)
     error (_("-stack-list-arguments: Usage: "	\
-	     "[--no-frame-filters] PRINT_VALUES [FRAME_LOW FRAME_HIGH]"));
+	     "[--no-frame-filters] [--skip-unavailable] "
+	     "PRINT_VALUES [FRAME_LOW FRAME_HIGH]"));
 
   if (argc - oind == 3)
     {
@@ -364,7 +380,7 @@ mi_cmd_stack_list_args (char *command, char **argv, int argc)
 	  QUIT;
 	  cleanup_frame = make_cleanup_ui_out_tuple_begin_end (uiout, "frame");
 	  ui_out_field_int (uiout, "level", i);
-	  list_args_or_locals (arguments, print_values, fi);
+	  list_args_or_locals (arguments, print_values, fi, skip_unavailable);
 	  do_cleanups (cleanup_frame);
 	}
     }
@@ -384,17 +400,20 @@ mi_cmd_stack_list_variables (char *command, char **argv, int argc)
   enum py_bt_status result = PY_BT_ERROR;
   int print_value;
   int oind = 0;
+  int skip_unavailable = 0;
 
   if (argc > 1)
     {
       int i;
       enum opt
       {
-	NO_FRAME_FILTERS
+	NO_FRAME_FILTERS,
+	SKIP_UNAVAILABLE,
       };
       static const struct mi_opt opts[] =
 	{
 	  {"-no-frame-filters", NO_FRAME_FILTERS, 0},
+	  {"-skip-unavailable", SKIP_UNAVAILABLE, 0},
 	  { 0, 0, 0 }
 	};
 
@@ -411,6 +430,9 @@ mi_cmd_stack_list_variables (char *command, char **argv, int argc)
 	    case NO_FRAME_FILTERS:
 	      raw_arg = oind;
 	      break;
+	    case SKIP_UNAVAILABLE:
+	      skip_unavailable = 1;
+	      break;
 	    }
 	}
     }
@@ -418,8 +440,8 @@ mi_cmd_stack_list_variables (char *command, char **argv, int argc)
   /* After the last option is parsed, there should be only
      'print-values'.  */
   if (argc - oind != 1)
-    error (_("-stack-list-variables: Usage: " \
+    error (_("-stack-list-variables: Usage: [--no-frame-filters] " \
-	     "[--no-frame-filters] PRINT_VALUES"));
+	     "[--skip-unavailable] PRINT_VALUES"));
 
    frame = get_selected_frame (NULL);
    print_value = mi_parse_print_values (argv[oind]);
@@ -436,7 +458,8 @@ mi_cmd_stack_list_variables (char *command, char **argv, int argc)
       if "--no-frame-filters" has been specified from the command.  */
    if (! frame_filters || raw_arg  || result == PY_BT_NO_FILTERS)
      {
-       list_args_or_locals (all, print_value, frame);
+       list_args_or_locals (all, print_value, frame,
+			    skip_unavailable);
      }
 }
 
@@ -444,19 +467,17 @@ mi_cmd_stack_list_variables (char *command, char **argv, int argc)
    WHAT and VALUES see list_args_or_locals.
 
    Errors are printed as if they would be the parameter value.  Use
-   zeroed ARG iff it should not be printed according to VALUES.  */
+   zeroed ARG iff it should not be printed according to VALUES.  If
+   SKIP_UNAVAILABLE is true, only print ARG if it is available.  */
 
 static void
 list_arg_or_local (const struct frame_arg *arg, enum what_to_list what,
-		   enum print_values values)
+		   enum print_values values, int skip_unavailable)
 {
   struct cleanup *old_chain;
   struct ui_out *uiout = current_uiout;
   struct ui_file *stb;
 
-  stb = mem_fileopen ();
-  old_chain = make_cleanup_ui_file_delete (stb);
-
   gdb_assert (!arg->val || !arg->error);
   gdb_assert ((values == PRINT_NO_VALUES && arg->val == NULL
 	       && arg->error == NULL)
@@ -467,6 +488,20 @@ list_arg_or_local (const struct frame_arg *arg, enum what_to_list what,
 	      || (arg->entry_kind == print_entry_values_only
 	          && (arg->val || arg->error)));
 
+  if (skip_unavailable && arg->val != NULL
+      && (value_entirely_unavailable (arg->val)
+	  /* A scalar object that does not have all bits available is
+	     also considered unavailable, because all bits contribute
+	     to its representation.  */
+	  || (val_print_scalar_type_p (value_type (arg->val))
+	      && !value_bytes_available (arg->val,
+					 value_embedded_offset (arg->val),
+					 TYPE_LENGTH (value_type (arg->val))))))
+    return;
+
+  stb = mem_fileopen ();
+  old_chain = make_cleanup_ui_file_delete (stb);
+
   if (values != PRINT_NO_VALUES || what == all)
     make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
 
@@ -516,11 +551,13 @@ list_arg_or_local (const struct frame_arg *arg, enum what_to_list what,
 
 /* Print a list of the objects for the frame FI in a certain form,
    which is determined by VALUES.  The objects can be locals,
-   arguments or both, which is determined by WHAT.  */
+   arguments or both, which is determined by WHAT.  If SKIP_UNAVAILABLE
+   is true, only print the arguments or local variables whose values
+   are available.  */
 
 static void
 list_args_or_locals (enum what_to_list what, enum print_values values,
-		     struct frame_info *fi)
+		     struct frame_info *fi, int skip_unavailable)
 {
   struct block *block;
   struct symbol *sym;
@@ -623,9 +660,9 @@ list_args_or_locals (enum what_to_list what, enum print_values values,
 		}
 
 	      if (arg.entry_kind != print_entry_values_only)
-		list_arg_or_local (&arg, what, values);
+		list_arg_or_local (&arg, what, values, skip_unavailable);
 	      if (entryarg.entry_kind != print_entry_values_no)
-		list_arg_or_local (&entryarg, what, values);
+		list_arg_or_local (&entryarg, what, values, skip_unavailable);
 	      xfree (arg.error);
 	      xfree (entryarg.error);
 	    }

gdb/testsuite/ChangeLog

@@ -1,3 +1,10 @@
+2013-08-27  Yao Qi  <yao@codesourcery.com>
+
+	* gdb.trace/entry-values.exp: Test unavailable entry value is
+	not shown when option '--skip-unavailable' is specified.
+	* gdb.trace/mi-trace-unavailable.exp (test_trace_unavailable):
+	Add tests for new option '--skip-unavailable'.
+
 2013-08-27  Yao Qi  <yao@codesourcery.com>
 
 	* lib/gdb.exp (gdb_remote_download): Don't pass $tofile to

gdb/testsuite/gdb.trace/entry-values.exp

@@ -276,4 +276,9 @@ gdb_test "tfind" "Found trace frame 0, .*" "tfind start"
 # Since 'global2' is not collected, j@entry is expected to be 'unavailable'.
 gdb_test "bt 1" "#0 .* foo \\(i=\[-\]?$decimal, i@entry=2, j=\[-\]?$decimal, j@entry=<unavailable>\\).*"
 
+# Test that unavailable "j@entry" is not shown when command option
+# --skip-unavailable is used.
+gdb_test "interpreter-exec mi \"-stack-list-arguments --skip-unavailable --simple-values\"" \
+    "\r\n\\^done,stack-args=\\\[frame={level=\"0\",args=\\\[{name=\"i\",type=\"int\",value=\".*\"},{name=\"i@entry\",type=\"int\",value=\"2\"},{name=\"j\",type=\"int\",value=\".*\"}\\\]},frame=.*\\\].*"
+
 gdb_test "tfind" "Target failed to find requested trace frame\..*"

gdb/testsuite/gdb.trace/mi-trace-unavailable.exp

@@ -106,16 +106,25 @@ proc test_trace_unavailable { data_source } {
 	mi_gdb_test "-stack-list-locals --simple-values" \
 	    ".*\\^done,locals=\\\[\{name=\"array\",type=\"unsigned char \\\[2\\\]\"\},\{name=\"i\",type=\"int\",value=\"<unavailable>\"\}\\\]" \
 	    "-stack-list-locals --simple-values"
+	mi_gdb_test "-stack-list-locals --skip-unavailable --simple-values" \
+	    ".*\\^done,locals=\\\[\{name=\"array\",type=\"unsigned char \\\[2\\\]\"\}\\\]" \
+	    "-stack-list-locals --skip-unavailable --simple-values"
 
 	# Test MI command '-stack-list-arguments'.
 	mi_gdb_test "-stack-list-arguments --simple-values" \
 	    ".*\\^done,stack-args=\\\[frame=\{level=\"0\",args=\\\[\{name=\"j\",type=\"int\",value=\"4\"\},\{name=\"s\",type=\"char \\\*\",value=\"<unavailable>\"\}\\\]\},.*\}.*" \
 	    "-stack-list-arguments --simple-values"
+	mi_gdb_test "-stack-list-arguments --skip-unavailable --simple-values" \
+	    ".*\\^done,stack-args=\\\[frame=\{level=\"0\",args=\\\[\{name=\"j\",type=\"int\",value=\"4\"\}\\\]\},.*\}.*" \
+	    "-stack-list-arguments --skip-unavailable --simple-values"
 
 	# Test MI command '-stack-list-variables'.
 	mi_gdb_test "-stack-list-variables --simple-values" \
 	    ".*\\^done,variables=\\\[\{name=\"j\",arg=\"1\",type=\"int\",value=\"4\"\},\{name=\"s\",arg=\"1\",type=\"char \\\*\",value=\"<unavailable>\"\},\{name=\"array\",type=\"unsigned char \\\[2\\\]\"\},\{name=\"i\",type=\"int\",value=\"<unavailable>\"\}\\\]" \
 	    "-stack-list-variables --simple-values"
+	mi_gdb_test "-stack-list-variables --skip-unavailable --simple-values" \
+	    ".*\\^done,variables=\\\[\{name=\"j\",arg=\"1\",type=\"int\",value=\"4\"\},\{name=\"array\",type=\"unsigned char \\\[2\\\]\"\}\\\]" \
+	    "-stack-list-variables --skip-unavailable --simple-values"
 
 	mi_gdb_test "-trace-find frame-number 1" \
 	    ".*\\^done,found=\"1\",tracepoint=\"${decimal}\",traceframe=\"1\",frame=\{.*" \

gdb/valprint.c

@@ -275,8 +275,8 @@ show_symbol_print (struct ui_file *file, int from_tty,
    we want to print scalar arguments, but not aggregate arguments.
    This function distinguishes between the two.  */
 
-static int
+int
-scalar_type_p (struct type *type)
+val_print_scalar_type_p (struct type *type)
 {
   CHECK_TYPEDEF (type);
   while (TYPE_CODE (type) == TYPE_CODE_REF)
@@ -770,7 +770,7 @@ val_print (struct type *type, const gdb_byte *valaddr, int embedded_offset,
 
   /* Handle summary mode.  If the value is a scalar, print it;
      otherwise, print an ellipsis.  */
-  if (options->summary && !scalar_type_p (type))
+  if (options->summary && !val_print_scalar_type_p (type))
     {
       fprintf_filtered (stream, "...");
       return;
@@ -802,7 +802,7 @@ value_check_printable (struct value *val, struct ui_file *stream,
 
   if (value_entirely_optimized_out (val))
     {
-      if (options->summary && !scalar_type_p (value_type (val)))
+      if (options->summary && !val_print_scalar_type_p (value_type (val)))
 	fprintf_filtered (stream, "...");
       else
 	val_print_optimized_out (stream);

gdb/valprint.h

@@ -211,4 +211,6 @@ extern void generic_printstr (struct ui_file *stream, struct type *type,
 
 extern void output_command_const (const char *args, int from_tty);
 
+extern int val_print_scalar_type_p (struct type *type);
+
 #endif

gdb/value.c

@@ -353,6 +353,26 @@ value_entirely_available (struct value *value)
   return 0;
 }
 
+int
+value_entirely_unavailable (struct value *value)
+{
+  /* We can only tell whether the whole value is available when we try
+     to read it.  */
+  if (value->lazy)
+    value_fetch_lazy (value);
+
+  if (VEC_length (range_s, value->unavailable) == 1)
+    {
+      struct range *t = VEC_index (range_s, value->unavailable, 0);
+
+      if (t->offset == 0
+	  && t->length == TYPE_LENGTH (value_enclosing_type (value)))
+	return 1;
+    }
+
+  return 0;
+}
+
 void
 mark_value_bytes_unavailable (struct value *value, int offset, int length)
 {

gdb/value.h

@@ -435,6 +435,10 @@ extern int value_bytes_available (const struct value *value,
    whole object is unavailable.  */
 extern int value_entirely_available (struct value *value);
 
+/* Like value_entirely_available, but return false if any byte in the
+   whole object is available.  */
+extern int value_entirely_unavailable (struct value *value);
+
 /* Mark VALUE's content bytes starting at OFFSET and extending for
    LENGTH bytes as unavailable.  */