[PATCH v2 4/4] Don't throw an error in 'info registers' for unavailable MIPS GP registers.

[John Baldwin]

'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 fcf0637245..02ab2181a6 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2017-04-25  John Baldwin  <jhb@FreeBSD.org>
 
+	* mips-tdep.c (print_gp_register_row): Don't error for unavailable
+	registers.
+
+2017-04-25  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 2364c2efdc..4b8c89de23 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,
+			    mips_abi_regsize (gdbarch) == 4 ? "<absent>"
+			    : "<unavailable>");
+	  col++;
+	  continue;
+	}
       /* pad small registers */
       for (byte = 0;
 	   byte < (mips_abi_regsize (gdbarch)
-- 
2.11.0