Add switch to control compact/verbose printing of capabilities

Add a new option set/show "print compact-capabilities" that default to "on".

This makes GDB default to printing capabilities in compact format, the CHERI
format.

gdb/ChangeLog:

2020-12-30  Luis Machado  <luis.machado@arm.com>

	* valprint.c (user_print_options): Initialize compact_capabilities.
	(show_print_compact_capabilities): New function.
	(generic_value_print_capability): Use compact_capabilities option.
	(value_print_option_defs): New compact_capabilities option.
	* valprint.h (value_print_options) <compact_capabilities>: New member
	variable.

gdb/ChangeLog

@@ -1,3 +1,12 @@
+2020-12-30  Luis Machado  <luis.machado@arm.com>
+
+	* valprint.c (user_print_options): Initialize compact_capabilities.
+	(show_print_compact_capabilities): New function.
+	(generic_value_print_capability): Use compact_capabilities option.
+	(value_print_option_defs): New compact_capabilities option.
+	* valprint.h (value_print_options) <compact_capabilities>: New member
+	variable.
+
 2020-11-11  Luis Machado  <luis.machado@arm.com>
 
 	* aarch64-tdep.c (aarch64_dwarf_reg_to_regnum): Don't return LR

gdb/valprint.c

@@ -114,6 +114,7 @@ struct value_print_options user_print_options =
   0,				/* format */
   0,				/* stop_print_at_null */
   0,				/* print_array_indexes */
+  1,				/* compact_capabilities */
   0,				/* deref_ref */
   1,				/* static_field_print */
   1,				/* pascal_static_field_print */
@@ -193,6 +194,18 @@ show_print_array_indexes (struct ui_file *file, int from_tty,
   fprintf_filtered (file, _("Printing of array indexes is %s.\n"), value);
 }
 
+/* By default we print capabilities in compact form.  This may be changed to
+   print them in a more verbose format.  */
+
+static void
+show_print_compact_capabilities (struct ui_file *file, int from_tty,
+				 struct cmd_list_element *c,
+				 const char *value)
+{
+  fprintf_filtered (file, _("Printing of compact capabilities is %s.\n"),
+			    value);
+}
+
 /* Print repeat counts if there are more than this many repetitions of an
    element in an array.  Referenced by the low level language dependent
    print routines.  */
@@ -513,7 +526,8 @@ generic_value_print_capability (struct value *val, struct ui_file *stream,
       uint128_t dummy_cap;
       memcpy (&dummy_cap, contents, length);
       capability cap (dummy_cap, tag);
-      fprintf_filtered (stream, "%s ", cap.to_str (true).c_str ());
+      fprintf_filtered (stream, "%s ",
+			cap.to_str (options->compact_capabilities).c_str ());
     }
 
   return;
@@ -3053,6 +3067,15 @@ static const gdb::option::option_def value_print_option_defs[] = {
     NULL, /* help_doc */
   },
 
+  boolean_option_def {
+    "compact-capabilities",
+    [] (value_print_options *opt) { return &opt->compact_capabilities; },
+    show_print_compact_capabilities, /* show_cmd_cb */
+    N_("Set compact printing of capabilities."),
+    N_("Show compact printing of capabilities."),
+    NULL, /* help_doc */
+  },
+
   uinteger_option_def {
     "elements",
     [] (value_print_options *opt) { return &opt->print_max; },

gdb/valprint.h

@@ -72,6 +72,9 @@ struct value_print_options
      an array.  */
   bool print_array_indexes;
 
+  /* True if capabilities should be displayed in a compact form.  */
+  bool compact_capabilities;
+
   /* If true, then dereference references, otherwise just print
      them like pointers.  */
   bool deref_ref;