Introduce gdb-specific %p format suffixes

This introduces a few gdb-specific %p format suffixes.  This is useful
for emitting gdb-specific output in an ergonomic way.  It also yields
code that is more i18n-friendly.

The comment before ui_out::message explains the details.

Note that the tests had to change a little.  When using one of the gdb
printf functions with styling, there can be spurious style changes
emitted to the output.  This did not seem worthwhile to fix, as the
low-level output functions are rather spaghetti-ish already, and I
didn't want to make them even worse.

This change also necessitated adding support for "*" as precision and
width in format_pieces.  These are used in various spots in gdb, and
it seemed better to me to implement them than to remove the uses.

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

	* unittests/format_pieces-selftests.c: Add gdb_format parameter.
	(test_gdb_formats): New function.
	(run_tests): Call it.
	(test_format_specifier): Update.
	* utils.h (fputs_filtered): Update comment.
	(vfprintf_styled, vfprintf_styled_no_gdbfmt)
	(fputs_styled_unfiltered): Declare.
	* utils.c (fputs_styled_unfiltered): New function.
	(vfprintf_maybe_filtered): Add gdbfmt parameter.
	(vfprintf_filtered): Update.
	(vfprintf_unfiltered, vprintf_filtered): Update.
	(vfprintf_styled, vfprintf_styled_no_gdbfmt): New functions.
	* ui-out.h (enum ui_out_flag) <unfiltered_output,
	disallow_ui_out_field>: New constants.
	(enum class field_kind): New.
	(struct base_field_s, struct signed_field_s): New.
	(signed_field): New function.
	(struct string_field_s): New.
	(string_field): New function.
	(struct styled_string_s): New.
	(styled_string): New function.
	(class ui_out) <message>: Add comment.
	<vmessage, call_do_message>: New methods.
	<do_message>: Add style parameter.
	* ui-out.c (ui_out::call_do_message, ui_out::vmessage): New
	methods.
	(ui_out::message): Rewrite.
	* mi/mi-out.h (class mi_ui_out) <do_message>: Add style
	parameter.
	* mi/mi-out.c (mi_ui_out::do_message): Add style parameter.
	* gdbsupport/format.h (class format_pieces) <format_pieces>: Add
	gdb_extensions parameter.
	(class format_piece): Add parameter to constructor.
	(n_int_args): New field.
	* gdbsupport/format.c (format_pieces::format_pieces): Add
	gdb_extensions parameter.  Handle '*'.
	* cli-out.h (class cli_ui_out) <do_message>: Add style parameter.
	* cli-out.c (cli_ui_out::do_message): Add style parameter.  Call
	vfprintf_styled_no_gdbfmt.
	(cli_ui_out::do_field_string, cli_ui_out::do_spaces)
	(cli_ui_out::do_text, cli_ui_out::field_separator): Allow
	unfiltered output.
	* ui-style.h (struct ui_file_style) <ptr>: New method.

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

	* gdb.base/style.exp: Update tests.

1 files changed, 140 insertions, 2 deletions

diff --git a/gdb/ui-out.h b/gdb/ui-out.h
index 6732f04..0bba128 100644
--- a/gdb/ui-out.h
+++ b/gdb/ui-out.h
@@ -53,6 +53,12 @@ enum ui_out_flag
 {
   ui_source_list = (1 << 0),
   fix_multi_location_breakpoint_output = (1 << 1),
+  /* For CLI output, this flag is set if unfiltered output is desired.
+     This should only be used by low-level formatting functions.  */
+  unfiltered_output = (1 << 2),
+  /* This indicates that %pF should be disallowed in a printf format
+     string.  */
+  disallow_ui_out_field = (1 << 3)
 };
 
 DEF_ENUM_FLAGS_TYPE (ui_out_flag, ui_out_flags);
@@ -68,6 +74,87 @@ enum ui_out_type
     ui_out_type_list
   };
 
+/* The possible kinds of fields.  */
+enum class field_kind
+  {
+    SIGNED,
+    STRING,
+  };
+
+/* The base type of all fields that can be emitted using %pF.  */
+
+struct base_field_s
+{
+  const char *name;
+  field_kind kind;
+};
+
+/* A signed integer field, to be passed to %pF in format strings.  */
+
+struct signed_field_s : base_field_s
+{
+  LONGEST val;
+};
+
+/* Construct a temporary signed_field_s on the caller's stack and
+   return a pointer to the constructed object.  We use this because
+   it's not possible to pass a reference via va_args.  */
+
+static inline signed_field_s *
+signed_field (const char *name, LONGEST val,
+	      signed_field_s &&tmp = {})
+{
+  tmp.name = name;
+  tmp.kind = field_kind::SIGNED;
+  tmp.val = val;
+  return &tmp;
+}
+
+/* A string field, to be passed to %pF in format strings.  */
+
+struct string_field_s : base_field_s
+{
+  const char *str;
+};
+
+/* Construct a temporary string_field_s on the caller's stack and
+   return a pointer to the constructed object.  We use this because
+   it's not possible to pass a reference via va_args.  */
+
+static inline string_field_s *
+string_field (const char *name, const char *str,
+	      string_field_s &&tmp = {})
+{
+  tmp.name = name;
+  tmp.kind = field_kind::STRING;
+  tmp.str = str;
+  return &tmp;
+}
+
+/* A styled string.  */
+
+struct styled_string_s
+{
+  /* The style.  */
+  ui_file_style style;
+
+  /* The string.  */
+  const char *str;
+};
+
+/* Construct a temporary styled_string_s on the caller's stack and
+   return a pointer to the constructed object.  We use this because
+   it's not possible to pass a reference via va_args.  */
+
+static inline styled_string_s *
+styled_string (const ui_file_style &style, const char *str,
+	       styled_string_s &&tmp = {})
+{
+  tmp.style = style;
+  tmp.str = str;
+  return &tmp;
+}
+
 class ui_out
 {
  public:
@@ -110,7 +197,55 @@ class ui_out
 
   void spaces (int numspaces);
   void text (const char *string);
+
+  /* Output a printf-style formatted string.  In addition to the usual
+     printf format specs, this supports a few GDB-specific
+     formatters:
+
+     - '%pF' - output a field.
+
+       The argument is a field, wrapped in any of the base_field_s
+       subclasses.  signed_field for integer fields, string_field for
+       string fields.  This is preferred over separate
+       uiout->field_signed(), uiout_>field_string() etc. calls when
+       the formatted message is translatable.  E.g.:
+
+         uiout->message (_("\nWatchpoint %pF deleted because the program has "
+                         "left the block in\n"
+                         "which its expression is valid.\n"),
+                         signed_field ("wpnum", b->number));
+
+     - '%p[' - output the following text in a specified style.
+       '%p]' - output the following text in the default style.
+
+       The argument to '%p[' is a ui_file_style pointer.  The argument
+       to '%p]' must be nullptr.
+
+       This is useful when you want to output some portion of a string
+       literal in some style.  E.g.:
+
+	 uiout->message (_(" %p[<repeats %u times>%p]"),
+			 metadata_style.style ().ptr (),
+			 reps, repeats, nullptr);
+
+     - '%ps' - output a styled string.
+
+       The argument is the result of a call to styled_string.  This is
+       useful when you want to output some runtime-generated string in
+       some style.  E.g.:
+
+	 uiout->message (_("this is a target address %ps.\n"),
+			 styled_string (address_style.style (),
+					paddress (gdbarch, pc)));
+
+     Note that these all "abuse" the %p printf format spec, in order
+     to be compatible with GCC's printf format checking.  This is OK
+     because code in GDB that wants to print a host address should use
+     host_address_to_string instead of %p.  */
   void message (const char *format, ...) ATTRIBUTE_PRINTF (2, 3);
+  void vmessage (const ui_file_style &in_style,
+		 const char *format, va_list args) ATTRIBUTE_PRINTF (3, 0);
+
   void wrap_hint (const char *identstring);
 
   void flush ();
@@ -161,8 +296,9 @@ class ui_out
     ATTRIBUTE_PRINTF (6,0) = 0;
   virtual void do_spaces (int numspaces) = 0;
   virtual void do_text (const char *string) = 0;
-  virtual void do_message (const char *format, va_list args)
-    ATTRIBUTE_PRINTF (2,0) = 0;
+  virtual void do_message (const ui_file_style &style,
+			   const char *format, va_list args)
+    ATTRIBUTE_PRINTF (3,0) = 0;
   virtual void do_wrap_hint (const char *identstring) = 0;
   virtual void do_flush () = 0;
   virtual void do_redirect (struct ui_file *outstream) = 0;
@@ -174,6 +310,8 @@ class ui_out
   { return false; }
 
  private:
+  void call_do_message (const ui_file_style &style, const char *format,
+			...);
 
   ui_out_flags m_flags;