[PATCH 4/4] Don't throw an error in 'info registers' for unavailable MIPS GP registers.

[John Baldwin <jhb@FreeBSD.org>]

'info registers' for MIPS throws an error and when it first encounters
an unavailable register.  This does not match other architectures
which annotate unavailable registers and continue to print out the
values of subsequent registers.  Replace the error by displaying an
aligned "<unavailable>".  This string is truncated when displaying a
32-bit register.

gdb/ChangeLog:

	* mips-tdep.c (print_gp_register_row): Don't error for unavailable
	registers.
---
 gdb/ChangeLog   |  5 +++++
 gdb/mips-tdep.c | 10 ++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f1ac925fec..96a187667d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2017-04-11  John Baldwin  <jhb@FreeBSD.org>
 
+	* mips-tdep.c (print_gp_register_row): Don't error for unavailable
+	registers.
+
+2017-04-11  John Baldwin  <jhb@FreeBSD.org>
+
 	* mips-tdep.c (print_gp_register_row): Replace printf_filtered
 	with fprintf_filtered.
 
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index 674b5098b0..4ec0c31341 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -6533,8 +6533,14 @@ print_gp_register_row (struct ui_file *file, struct frame_info *frame,
 
       /* OK: get the data in raw format.  */
       if (!deprecated_frame_register_read (frame, regnum, raw_buffer))
-	error (_("can't read register %d (%s)"),
-	       regnum, gdbarch_register_name (gdbarch, regnum));
+	{
+	  fprintf_filtered (file, "%*.*s ",
+			    (int) mips_abi_regsize (gdbarch) * 2,
+			    (int) mips_abi_regsize (gdbarch) * 2,
+			    "<unavailable>");
+	  col++;
+	  continue;
+	}
       /* pad small registers */
       for (byte = 0;
 	   byte < (mips_abi_regsize (gdbarch)
-- 
2.11.0