[binutils-gdb] Fix unintialized memory in aarch64 opcodes.

[Tamar Christina]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b3ac5c6c286c5b5c1909628e85754edfb403cf1a

commit b3ac5c6c286c5b5c1909628e85754edfb403cf1a
Author: Tamar Christina <tamar.christina@arm.com>
Date:   Tue May 1 17:11:11 2018 +0100

    Fix unintialized memory in aarch64 opcodes.
    
    This patch fixes an issue where the memory for the opcode structure is not zero'd before
    the first exit branch. So there is one failure mode for which uninitialized memory
    is returned.
    
    This causes weird failures when the return code is not checked before inst is used.
    
    opcodes/
    
    	* aarch64-dis.c (aarch64_opcode_decode): Moved memory clear code.

Diff:
---
 opcodes/ChangeLog     | 4 ++++
 opcodes/aarch64-dis.c | 6 +++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index e0834bf..3c2cf16 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,7 @@
+2018-05-01  Tamar Christina  <tamar.christina@arm.com>
+
+	* aarch64-dis.c (aarch64_opcode_decode): Moved memory clear code.
+
 2018-04-30  Francois H. Theron <francois.theron@netronome.com>
 
 	Makefile.am: Added nfp-dis.c.
diff --git a/opcodes/aarch64-dis.c b/opcodes/aarch64-dis.c
index c63f595..e7bece9 100644
--- a/opcodes/aarch64-dis.c
+++ b/opcodes/aarch64-dis.c
@@ -2733,6 +2733,9 @@ aarch64_opcode_decode (const aarch64_opcode *opcode, const aarch64_insn code,
 
   assert (opcode && inst);
 
+  /* Clear inst.  */
+  memset (inst, '\0', sizeof (aarch64_inst));
+
   /* Check the base opcode.  */
   if ((code & opcode->mask) != (opcode->opcode & opcode->mask))
     {
@@ -2740,9 +2743,6 @@ aarch64_opcode_decode (const aarch64_opcode *opcode, const aarch64_insn code,
       goto decode_fail;
     }
 
-  /* Clear inst.  */
-  memset (inst, '\0', sizeof (aarch64_inst));
-
   inst->opcode = opcode;
   inst->value = code;