[PATCH] gdb: Fix riscv ARI issues

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

Fixes some ARI issues in recently added riscv code, the ARI email is:

  https://sourceware.org/ml/gdb-patches/2018-03/msg00156.html

gdb/ChangeLog:

	* riscv-tdep.c (riscv_register_name): Use xsnprintf instead of
	sprintf.
	(riscv_insn::fetch_instruction): Use gdb_assert instead of
	internal_error.
	(riscv_print_arg_location): Use gdb_assert_not_reached instead of
	error.
	(riscv_push_dummy_call): Likewise.
---
 gdb/ChangeLog    | 10 ++++++++++
 gdb/riscv-tdep.c | 14 ++++++--------
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/gdb/riscv-tdep.c b/gdb/riscv-tdep.c
index 11b12279321..d84e7aba76a 100644
--- a/gdb/riscv-tdep.c
+++ b/gdb/riscv-tdep.c
@@ -481,7 +481,7 @@ riscv_register_name (struct gdbarch *gdbarch, int regnum)
     {
       static char buf[20];
 
-      sprintf (buf, "csr%d", regnum - RISCV_FIRST_CSR_REGNUM);
+      xsnprintf (buf, 20, "csr%d", regnum - RISCV_FIRST_CSR_REGNUM);
       return buf;
     }
 
@@ -1049,12 +1049,10 @@ riscv_insn::fetch_instruction (struct gdbarch *gdbarch,
 
   /* If we need more, grab it now.  */
   instlen = riscv_insn_length (buf[0]);
+  gdb_assert (instlen <= sizeof (buf));
   *len = instlen;
-  if (instlen > sizeof (buf))
-    internal_error (__FILE__, __LINE__,
-		    _("%s: riscv_insn_length returned %i"),
-		    __func__, instlen);
-  else if (instlen > 2)
+
+  if (instlen > 2)
     {
       status = target_read_memory (addr + 2, buf + 2, instlen - 2);
       if (status)
@@ -2009,7 +2007,7 @@ riscv_print_arg_location (ui_file *stream, struct gdbarch *gdbarch,
       break;
 
     default:
-      error ("unknown argument location type");
+      gdb_assert_not_reached ("unknown argument location type");
     }
 }
 
@@ -2149,7 +2147,7 @@ riscv_push_dummy_call (struct gdbarch *gdbarch,
 	  break;
 
 	default:
-	  error ("unknown argument location type");
+	  gdb_assert_not_reached ("unknown argument location type");
 	}
 
       if (second_arg_length > 0)
-- 
2.14.3