Introduce metadata style

This introduces a new "metadata" style and changes many places in gdb
to use it.  The idea here is to let the user distinguish gdb output
from output that (conceptually at least) comes directly from the
inferior.  The newly-styled category includes text that gdb
traditionally surrounds in "<...>", like "<unavailable>".

I only added a single test for this.  In many cases this output is
difficult to test.  Also, while developing this errors in the
implementation of the new printf formats showed up as regressions.

gdb/ChangeLog
2019-10-01  Tom Tromey  <tom@tromey.com>

	* p-lang.c (pascal_printstr): Use metadata style.
	* value.c (show_convenience): Use metadata style.
	* valprint.c (valprint_check_validity, val_print_optimized_out)
	(val_print_not_saved, val_print_unavailable)
	(val_print_invalid_address, generic_val_print, val_print)
	(value_check_printable, val_print_array_elements): Use metadata
	style.
	* ui-out.h (class ui_out) <field_fmt>: New overload.
	<do_field_fmt>: Add style parameter.
	* ui-out.c (ui_out::field_fmt): New overload.
	* typeprint.c (type_print_unknown_return_type)
	(val_print_not_allocated, val_print_not_associated): Use metadata
	style.
	* tui/tui-out.h (class tui_ui_out) <do_field_fmt>: Add style
	parameter.
	* tui/tui-out.c (tui_ui_out::do_field_fmt): Update.
	* tracepoint.c (tvariables_info_1): Use metadata style.
	* stack.c (print_frame_arg, print_frame_info, print_frame)
	(info_frame_command_core): Use metadata style.
	* skip.c (info_skip_command): Use metadata style.
	* rust-lang.c (rust_print_enum): Use metadata style.
	* python/py-prettyprint.c (print_stack_unless_memory_error): Use
	metadata style.
	* python/py-framefilter.c (py_print_single_arg): Use metadata
	style.
	* printcmd.c (do_one_display, print_variable_and_value): Use
	metadata style.
	* p-valprint.c (pascal_val_print)
	(pascal_object_print_value_fields): Use metadata style.
	* p-typeprint.c (pascal_type_print_base): Use metadata style.
	* mi/mi-out.h (class mi_ui_out) <do_field_fmt>: Add style
	parameter.
	* mi/mi-out.c (mi_ui_out::do_field_fmt): Update.
	* m2-valprint.c (m2_print_long_set): Use metadata style.
	* m2-typeprint.c (m2_print_type): Use metadata style.
	* infcmd.c (print_return_value_1): Use metadata style.
	* gnu-v3-abi.c (print_one_vtable): Use metadata style.
	* f-valprint.c (info_common_command_for_block): Use metadata
	style.
	* f-typeprint.c (f_type_print_base): Use metadata style.
	* expprint.c (print_subexp_standard): Use metadata style.
	* cp-valprint.c (cp_print_value_fields): Use metadata style.
	* cli/cli-style.h (class cli_style_option): Add constructor.
	(metadata_style): Declare.
	* cli/cli-style.c (metadata_style): New global.
	(_initialize_cli_style): Register metadata style.
	* cli-out.h (class cli_ui_out) <do_field_fmt>: Add style
	parameter.
	* cli-out.c (cli_ui_out::do_field_fmt): Update.
	* c-typeprint.c (c_type_print_base_struct_union)
	(c_type_print_base_1): Use metadata style.
	* breakpoint.c (watchpoint_value_print)
	(print_one_breakpoint_location): Use metadata style.
	* break-catch-syscall.c (print_one_catch_syscall): Use metadata
	style.
	* break-catch-sig.c (signal_catchpoint_print_one): Use metadata
	style.
	* ada-valprint.c (val_print_packed_array_elements, printstr)
	(print_field_values, ada_val_print_ref, ada_val_print): Use
	metadata style.
	* ada-typeprint.c (print_array_type, ada_print_type): Use metadata
	style.
	* ada-tasks.c (print_ada_task_info, info_task): Use metadata
	style.
	* ada-lang.c (user_select_syms): Use metadata style.

gdb/testsuite/ChangeLog
2019-10-01  Tom Tromey  <tom@tromey.com>

	* lib/gdb-utils.exp (style): Handle "metadata" argument.
	* gdb.base/style.exp: Add metadata style test.

2 files changed, 16 insertions, 0 deletions

diff --git a/gdb/cli/cli-style.c b/gdb/cli/cli-style.c
index ea30177..a0c5c0a 100644
--- a/gdb/cli/cli-style.c
+++ b/gdb/cli/cli-style.c
@@ -85,6 +85,10 @@ cli_style_option title_style ("title", ui_file_style::BOLD);
 
 /* See cli-style.h.  */
 
+cli_style_option metadata_style ("metadata", ui_file_style::DIM);
+
+/* See cli-style.h.  */
+
 cli_style_option::cli_style_option (const char *name,
 				    ui_file_style::basic_color fg)
   : m_name (name),
@@ -372,4 +376,11 @@ Highlight display styling.\n\
 Configure highlight colors and display intensity\n\
 Some commands use the highlight style to draw the attention to a part\n\
 of their output."));
+
+  STYLE_ADD_SETSHOW_COMMANDS (metadata_style,
+			      _("\
+Metadata display styling\n\
+Configure metadata colors and display intensity\n\
+The \"metadata\" style is used when GDB displays information about\n\
+your data, for example \"<unavailable>\""));
 }
diff --git a/gdb/cli/cli-style.h b/gdb/cli/cli-style.h
index 826162f..6716471 100644
--- a/gdb/cli/cli-style.h
+++ b/gdb/cli/cli-style.h
@@ -34,6 +34,9 @@ public:
   /* Construct a CLI style option with an intensity.  */
   cli_style_option (const char *name, ui_file_style::intensity i);
 
+  /* Construct a CLI style option with an intensity.  */
+  cli_style_option (ui_file_style::intensity val);
+
   /* Return a ui_file_style corresponding to the settings in this CLI
      style.  */
   ui_file_style style () const;
@@ -108,6 +111,8 @@ extern cli_style_option highlight_style;
 /* The title style.  */
 extern cli_style_option title_style;
 
+/* The metadata style.  */
+extern cli_style_option metadata_style;
 
 /* True if source styling is enabled.  */
 extern bool source_styling;