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'.

2 files changed, 21 insertions, 3 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 61a6f41..67d3320 100644
--- a/gdb/doc/ChangeLog
+++ b/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
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index c88ee65..21250fe 100644
--- a/gdb/doc/gdb.texinfo
+++ b/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