[PATCH v3 1/2] Record ARM THUMB2 PLD/PLI cache instructions

[Trent Piepho <tpiepho@impinj.com>]

These weren't decoded correctly and trigger an unknown instruction error
when recording.  The ARM format was handled, but not the 32-bit THUMB2
format.

Since they are only hints that may affect cache state, there is nothing
to record.

gdb/ChangeLog
2018-09-28  Trent Piepho  <tpiepho@impinj.com>

        PR gdb/23725
        * gdb/arm-tdep.c (thumb2_record_ld_mem_hints): Decode thumb2 PLD/PLI
---
 gdb/arm-tdep.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index c3280ee211..90936ada8e 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -12683,6 +12683,14 @@ thumb2_record_ld_mem_hints (insn_decode_record *thumb2_insn_r)
                 record_buf);
       return ARM_RECORD_SUCCESS;
     }
+  else
+    {
+      if (bits (thumb2_insn_r->arm_insn, 20, 22) == 0x1)
+	{
+	  /* Handle PLD, PLI affect only caches, so nothing to record */
+	  return ARM_RECORD_SUCCESS;
+	}
+    }
 
   return ARM_RECORD_FAILURE;
 }
-- 
2.14.4