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, 5 insertions, 4 deletions

diff --git a/gdb/mi/mi-out.c b/gdb/mi/mi-out.c
index 71af4865e97..ad4252f7122 100644
--- a/gdb/mi/mi-out.c
+++ b/gdb/mi/mi-out.c
@@ -141,8 +141,8 @@ mi_ui_out::do_field_string (int fldno, int width, ui_align align,
 
 void
 mi_ui_out::do_field_fmt (int fldno, int width, ui_align align,
-			 const char *fldname, const char *format,
-			 va_list args)
+			 const char *fldname, const ui_file_style &style,
+			 const char *format, va_list args)
 {
   ui_file *stream = m_streams.back ();
   field_separator ();
diff --git a/gdb/mi/mi-out.h b/gdb/mi/mi-out.h
index 9393809b5f2..c8b42c295ee 100644
--- a/gdb/mi/mi-out.h
+++ b/gdb/mi/mi-out.h
@@ -68,8 +68,9 @@ protected:
 				const char *fldname, const char *string,
 				const ui_file_style &style) override;
   virtual void do_field_fmt (int fldno, int width, ui_align align,
-			  const char *fldname, const char *format, va_list args)
-    override ATTRIBUTE_PRINTF (6,0);
+			     const char *fldname, const ui_file_style &style,
+			     const char *format, va_list args)
+    override ATTRIBUTE_PRINTF (7,0);
   virtual void do_spaces (int numspaces) override;
   virtual void do_text (const char *string) override;
   virtual void do_message (const ui_file_style &style,