[PATCH] Limit register display len to preserve multiple TUI columns

[Bogdan Harjoc <harjoc at gmail dot com>]

When TUI layout is regs+asm+cmd, if a register value can be resolved
to a symbol with a long name, the register window becomes
single-column. That makes it hard to look at registers since you have
to scroll down in the regs window.

I couldn't figure out how to make use of gdb print settings to limit
the display length, so I wrote a patch to get the max-reg-len from the
environment (attached). I could change it to make the max-len a gdb
setting, or guess it somehow if someone suggests how.

Regards,
Bogdan

diff --git a/gdb/tui/tui-regs.c b/gdb/tui/tui-regs.c
index 7059b02..bf2c998 100644
--- a/gdb/tui/tui-regs.c
+++ b/gdb/tui/tui-regs.c
@@ -311,9 +311,13 @@ tui_display_registers_from (int start_element_no)
     {
       int i = start_element_no;
       int j, item_win_width, cur_y;
+      int len_env = 0;
+      const char *env = getenv("GDB_MAX_REG_LEN");
+
+      if (env) len_env = atoi(env);
 
       int max_len = 0;
-      for (i = 0; i < display_info->regs_content_count; i++)
+      for (; i < display_info->regs_content_count; i++)
         {
           struct tui_data_element *data;
           struct tui_gen_win_info *data_item_win;
@@ -326,17 +330,26 @@ tui_display_registers_from (int start_element_no)
           len = 0;
           p = data->content;
           if (p != 0)
-            while (*p)
-              {
-                if (*p++ == '\t')
-                  len = 8 * ((len / 8) + 1);
-                else
-                  len++;
-              }
+	    {
+	      while (*p)
+		{
+		  if (*p++ == '\t')
+		    len = 8 * ((len / 8) + 1);
+		  else
+		    len++;
+		}
+
+	      if (len_env && len > len_env)
+	      {
+		len = len_env;
+		data->content[len] = 0;
+	      }
+	    }
 
           if (len > max_len)
             max_len = len;
         }
+
       item_win_width = max_len + 1;
       i = start_element_no;