[PATCH v2] Align natural-format register values to the same column

[Ruslan Kabatsayev <b7.10110111@gmail.com>]

Currently, commands such as "info reg", "info all-reg", as well as register
window in the TUI print badly aligned columns, like here:

eax            0x1      1
ecx            0xffffd3e0       -11296
edx            0xffffd404       -11260
ebx            0xf7fa5ff4       -134586380
esp            0xffffd390       0xffffd390
ebp            0xffffd3c8       0xffffd3c8
esi            0x0      0
edi            0x0      0
eip            0x8048b60        0x8048b60 <main+16>
eflags         0x286    [ PF SF IF ]
cs             0x23     35
ss             0x2b     43
ds             0x2b     43
es             0x2b     43
fs             0x0      0
gs             0x63     99

After this patch, these commands print the third column values consistently
aligned one under another, provided the second column is not too long.
Originally, the third column was (attempted to be) aligned using a simple tab
character. Lots of tests in the test suite check for it, so this patch retains
the tab in the output after the second column. This allows these tests to
continue working unchanged. What is different is that now the tab may be
followed by several spaces, which complete the task of aligning the third
column when the sole tab doesn't work well.

gdb/ChangeLog:

	* infcmd.c (default_print_one_register_info): Align natural-
	format column value consistently one after another.
---
 gdb/infcmd.c |   35 ++++++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index defa7b0..56cdee2 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -2270,6 +2270,15 @@ path_command (char *dirname, int from_tty)
 }
 \f
 
+static void
+pad_to_column_prepending_tab (string_file& stream, int col)
+{
+  const int size_with_tab = stream.size () / 8 * 8 + 8;
+  stream.putc ('\t');
+  if (size_with_tab < col)
+      stream.puts (n_spaces (col - size_with_tab));
+}
+
 /* Print out the register NAME with value VAL, to FILE, in the default
    fashion.  */
 
@@ -2280,9 +2289,15 @@ default_print_one_register_info (struct ui_file *file,
 {
   struct type *regtype = value_type (val);
   int print_raw_format;
+  string_file format_stream;
+  enum tab_stops
+    {
+	value_column_1=15,
+	value_column_2=32,
+    };
 
-  fputs_filtered (name, file);
-  print_spaces_filtered (15 - strlen (name), file);
+  format_stream.puts (name);
+  format_stream.puts (n_spaces (value_column_1 - strlen (name)));
 
   print_raw_format = (value_entirely_available (val)
 		      && !value_optimized_out (val));
@@ -2301,14 +2316,15 @@ default_print_one_register_info (struct ui_file *file,
 
       val_print (regtype,
 		 value_embedded_offset (val), 0,
-		 file, 0, val, &opts, current_language);
+		 &format_stream, 0, val, &opts, current_language);
 
       if (print_raw_format)
 	{
-	  fprintf_filtered (file, "\t(raw ");
-	  print_hex_chars (file, valaddr, TYPE_LENGTH (regtype), byte_order,
+	  pad_to_column_prepending_tab (format_stream, value_column_2);
+	  format_stream.puts ("(raw ");
+	  print_hex_chars (&format_stream, valaddr, TYPE_LENGTH (regtype), byte_order,
 			   true);
-	  fprintf_filtered (file, ")");
+	  format_stream.puts (")");
 	}
     }
   else
@@ -2320,20 +2336,21 @@ default_print_one_register_info (struct ui_file *file,
       opts.deref_ref = 1;
       val_print (regtype,
 		 value_embedded_offset (val), 0,
-		 file, 0, val, &opts, current_language);
+		 &format_stream, 0, val, &opts, current_language);
       /* If not a vector register, print it also according to its
 	 natural format.  */
       if (print_raw_format && TYPE_VECTOR (regtype) == 0)
 	{
+	  pad_to_column_prepending_tab (format_stream, value_column_2);
 	  get_user_print_options (&opts);
 	  opts.deref_ref = 1;
-	  fprintf_filtered (file, "\t");
 	  val_print (regtype,
 		     value_embedded_offset (val), 0,
-		     file, 0, val, &opts, current_language);
+		     &format_stream, 0, val, &opts, current_language);
 	}
     }
 
+  fputs_filtered (format_stream.c_str (), file);
   fprintf_filtered (file, "\n");
 }
 
-- 
1.7.10.2