ART: optimizing compiler: initial support for ARM64.

The ARM64 port uses VIXL for code generation, to which it defers work
like label binding and branch resolving, register type coherency
checking, and immediate values handling.

Change-Id: I0a44508c0c991f472a63e67b3469cdd878fe1a68
Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com>
Signed-off-by: Alexandre Rames <alexandre.rames@arm.com>
diff --git a/compiler/utils/assembler.h b/compiler/utils/assembler.h
index 91b8d8ab..2b0c94c 100644
--- a/compiler/utils/assembler.h
+++ b/compiler/utils/assembler.h
@@ -118,6 +118,7 @@
   friend class arm::ArmAssembler;
   friend class arm::Arm32Assembler;
   friend class arm::Thumb2Assembler;
+  friend class arm64::Arm64Assembler;
   friend class mips::MipsAssembler;
   friend class x86::X86Assembler;
   friend class x86_64::X86_64Assembler;