[PATCH 2/2] gdb: add new version style

[Andrew Burgess <andrew.burgess@embecosm.com>]

This commit adds a new 'version' style, which replaces the hard coded
styling currently used for GDB's version string.  GDB's version number
is displayed:

  1. In the output of 'show version', and

  2. When GDB starts up (without the --quiet option).

This new style can only ever affect the first of these two cases as
the second case is printed before GDB has processed any initialization
files, or processed any GDB commands passed on the command line.

However, because the first case exists I think this commit makes
sense, it means the style is no longer hard coded into GDB, and we can
add some tests that the style can be enabled/disabled correctly.

This commit is an alternative to a patch Tom posted here:

  https://sourceware.org/pipermail/gdb-patches/2020-June/169820.html

I've used the style name 'version' instead of 'startup' to reflect
what the style is actually used for.  If other parts of the startup
text end up being highlighted I imagine they would get their own
styles based on what is being highlighted.  I feel this is more inline
with the other style names that are already in use within GDB.

I also decoupled adding this style from the idea of startup options,
and the possibility of auto-saving startup options.  Those ideas can
be explored in later patches.

gdb/ChangeLog:

	* cli/cli-style.c: Add 'cli/cli-setshow.h' include.
	(version_style): Define.
	(cli_style_option::cli_style_option): Add intensity parameter, and
	use as appropriate.
	(_initialize_cli_style): Register version style set/show commands.
	* cli/cli-style.h (cli_style_option): Add intensity parameter.
	(version_style): Declare.
	* top.c (print_gdb_version): Use version_stype, and styled_string
	to print the GDB version string.

gdb/doc/ChangeLog:

	* gdb.texinfo (Output Styling): Document version style.

gdb/testsuite/ChangeLog:

	* gdb.base/style.exp (run_style_tests): Add version string test.
	(test_startup_version_string): Use version style name.
	* lib/gdb-utils.exp (style): Handle version style name.
---
 gdb/ChangeLog                    | 12 ++++++++++++
 gdb/NEWS                         |  5 +++++
 gdb/cli/cli-style.c              | 17 +++++++++++++++--
 gdb/cli/cli-style.h              |  6 +++++-
 gdb/doc/ChangeLog                |  4 ++++
 gdb/doc/gdb.texinfo              | 12 ++++++++++++
 gdb/testsuite/ChangeLog          |  6 ++++++
 gdb/testsuite/gdb.base/style.exp |  8 +++++++-
 gdb/testsuite/lib/gdb-utils.exp  |  1 +
 gdb/top.c                        | 11 +++--------
 10 files changed, 70 insertions(+), 12 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index 66702862efb..0ba0c0b5ea2 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -171,6 +171,11 @@ show exec-file-mismatch -- Show exec-file-mismatch handling (ask|warn|off).
   executable file; if 'warn', just display a warning; if 'off', don't
   attempt to detect a mismatch.
 
+set style version foreground COLOR
+set style version background COLOR
+set style version intensity VALUE
+  Control the styling of GDB's version number text.
+
 tui new-layout NAME WINDOW WEIGHT [WINDOW WEIGHT]...
   Define a new TUI layout, specifying its name and the windows that
   will be displayed.
diff --git a/gdb/cli/cli-style.c b/gdb/cli/cli-style.c
index cbedd30ea74..8b4b6b24cda 100644
--- a/gdb/cli/cli-style.c
+++ b/gdb/cli/cli-style.c
@@ -19,6 +19,7 @@
 
 #include "defs.h"
 #include "cli/cli-cmds.h"
+#include "cli/cli-setshow.h"
 #include "cli/cli-style.h"
 #include "source-cache.h"
 #include "observable.h"
@@ -98,13 +99,19 @@ cli_style_option metadata_style ("metadata", ui_file_style::DIM);
 
 /* See cli-style.h.  */
 
+cli_style_option version_style ("version", ui_file_style::MAGENTA,
+				ui_file_style::BOLD);
+
+/* See cli-style.h.  */
+
 cli_style_option::cli_style_option (const char *name,
-				    ui_file_style::basic_color fg)
+				    ui_file_style::basic_color fg,
+				    ui_file_style::intensity intensity)
   : changed (name),
     m_name (name),
     m_foreground (cli_colors[fg - ui_file_style::NONE]),
     m_background (cli_colors[0]),
-    m_intensity (cli_intensities[ui_file_style::NORMAL])
+    m_intensity (cli_intensities[intensity])
 {
 }
 
@@ -382,4 +389,10 @@ TUI window that does have the focus."),
 						&style_set_list,
 						&style_show_list,
 						true);
+
+  version_style.add_setshow_commands (no_class, _("\
+Version string display styling.\n\
+Configure colors used to display the GDB version string."),
+				      &style_set_list, &style_show_list,
+				      false);
 }
diff --git a/gdb/cli/cli-style.h b/gdb/cli/cli-style.h
index cd51bf4aa94..187e1d07ce7 100644
--- a/gdb/cli/cli-style.h
+++ b/gdb/cli/cli-style.h
@@ -30,7 +30,8 @@ class cli_style_option
 public:
 
   /* Construct a CLI style option with a foreground color.  */
-  cli_style_option (const char *name, ui_file_style::basic_color fg);
+  cli_style_option (const char *name, ui_file_style::basic_color fg,
+		    ui_file_style::intensity = ui_file_style::NORMAL);
 
   /* Construct a CLI style option with an intensity.  */
   cli_style_option (const char *name, ui_file_style::intensity i);
@@ -124,6 +125,9 @@ extern cli_style_option tui_border_style;
 /* The border style of a TUI window that does have the focus.  */
 extern cli_style_option tui_active_border_style;
 
+/* The style to use for the GDB version string.  */
+extern cli_style_option version_style;
+
 /* True if source styling is enabled.  */
 extern bool source_styling;
 
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 69fa6b709bf..37f97bfb2b2 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -25872,6 +25872,18 @@
 @code{set style address} family of commands.  By default, this style's
 foreground color is blue.
 
+@item version
+Control the styling of @value{GDBN}'s version number text.  By
+default, this style's foreground color is magenta and it has bold
+intensity.  The version number is displayed in two placed, the output
+of @command{show version}, and when @value{GDBN} starts up.
+
+Currently the version string displayed at startup is printed before
+@value{GDBN} has parsed any command line options, or parsed any
+command files, so there is currently no way to control the styling of
+this string.  However, @value{GDBN}'s @code{--quiet} command line option
+can be used to disable printing of the version string on startup.
+
 @item title
 Control the styling of titles.  These are managed with the
 @code{set style title} family of commands.  By default, this style's
diff --git a/gdb/testsuite/gdb.base/style.exp b/gdb/testsuite/gdb.base/style.exp
index 58c8da0a10e..dfbadd6c1af 100644
--- a/gdb/testsuite/gdb.base/style.exp
+++ b/gdb/testsuite/gdb.base/style.exp
@@ -264,6 +264,12 @@ proc run_style_tests { } {
 	gdb_test "p 5" \
 	    "Warning: '[style p title]', an alias for the command '[style print title]', is deprecated.*Use '[style new_p title]'.*" \
 	    "p deprecated warning, with replacement"
+
+	# Check that the version string is styled in the output of 'show
+	# version', and that this styling can be disabled.
+	set vers [style "GNU gdb.*" version]
+	gdb_test "show version" "${vers}.*" \
+	    "version is styled in 'show version'"
     }
 }
 
@@ -274,7 +280,7 @@ proc test_startup_version_string { } {
     gdb_exit
     gdb_spawn
 
-    set vers [style "GNU gdb.*" "35;1"]
+    set vers [style "GNU gdb.*" version]
     gdb_test "" "${vers}.*" "version is styled at startup"
 }
 
diff --git a/gdb/testsuite/lib/gdb-utils.exp b/gdb/testsuite/lib/gdb-utils.exp
index 000e3800cd9..ad7d2884aae 100644
--- a/gdb/testsuite/lib/gdb-utils.exp
+++ b/gdb/testsuite/lib/gdb-utils.exp
@@ -55,6 +55,7 @@ proc style {str style} {
 	variable { set style 36 }
 	address { set style 34 }
 	metadata { set style 2 }
+	version { set style "35;1" }
     }
     return "\033\\\[${style}m${str}\033\\\[m"
 }
diff --git a/gdb/top.c b/gdb/top.c
index 2c13864e120..92090bccbf4 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1395,14 +1395,9 @@ print_gdb_version (struct ui_file *stream, bool interactive)
      program to parse, and is just canonical program name and version
      number, which starts after last space.  */
 
-  ui_file_style style;
-  if (interactive)
-    {
-      ui_file_style nstyle = { ui_file_style::MAGENTA, ui_file_style::NONE,
-			       ui_file_style::BOLD };
-      style = nstyle;
-    }
-  fprintf_styled (stream, style, "GNU gdb %s%s\n", PKGVERSION, version);
+  std::string v_str = string_printf ("GNU gdb %s%s", PKGVERSION, version);
+  fprintf_filtered (stream, "%ps\n",
+		    styled_string (version_style.style (), v_str.c_str ()));
 
   /* Second line is a copyright notice.  */
 
-- 
2.25.4